Updated on 2022/11/28

写真a

 
WASHIO, Masakazu
 
Scopus Paper Info  
Paper Count: 0  Citation Count: 0  h-index: 12

Citation count denotes the number of citations in papers published for a particular year.

Affiliation
Faculty of Science and Engineering, School of Advanced Science and Engineering
Job title
Professor

Concurrent Post

  • Faculty of Science and Engineering   Graduate School of Advanced Science and Engineering

  • Affiliated organization   Global Education Center

Research Institute

  • 2020
    -
    2022

    理工学術院総合研究所   兼任研究員

Education

  •  
    -
    1976

    The University of Tokyo   Faculty of Engineering  

Degree

  • 東京大学   工学博士

  • Doctor of Engineering

  • 工学博士 (東京大学)

Professional Memberships

  •  
     
     

    RadTech Japan

  •  
     
     

    原子力学会

  •  
     
     

    高分子学会

  •  
     
     

    日本化学会

  •  
     
     

    Physical Society of Japan

  •  
     
     

    Japanese Society of Radiation Chemistry

▼display all

 

Research Areas

  • Nuclear engineering

  • Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

  • Fundamental physical chemistry

Research Interests

  • Electron Accelerator, High Brightness X ray, Pulse Radiolysis,Elementary Particles Physics,Nuclear Physics & Cosmic Ray Physics,Accelerator Physics

Papers

  • Trapped radical behavior of electron beam irradiated polytetrafluoroethylene fine powder at various temperatures

    Akihiro Oshima, Hiroto Horiuchi, Atsushi Nakamura, Shun Kobayashi, Ayana Terui, Ayano Mino, Ryoya Shimura, Masakazu Washio

    Scientific Reports   11 ( 1 )  2021.12

     View Summary

    Polytetrafluoroethylene (PTFE) fine powder with 93% crystallinity was irradiated by an electron beam (EB) at various temperatures under a nitrogen atmosphere. Trapped free radicals in PTFE were studied using electron spin resonance (ESR) spectroscopy. The observed spectra of the samples exposed to air after irradiation at various temperatures showed asymmetrical signals, which are middle-chain type peroxide macroradicals derived from fluoroalkyl radicals. The radical yields at each irradiation temperature increased with increasing absorbed dose, and eventually saturated. The higher irradiation temperature resulted in higher radical yields when compared at the same exposed dose. Furthermore, the G-value of the radicals (G(R·)) increases with increasing irradiation temperatures corresponding to each relaxation and transition temperature. It is concluded that the chain reaction by the fluorine extraction from the main chain due to the end-chain radical generated via β-scission after dissociative electron attachment (DEA) is enhanced by the synergistic effect of heat and radiation.

    DOI PubMed

    Scopus

    3
    Citation
    (Scopus)
  • Independent contribution of optical attenuation length in ultrafast laser-induced structural change

    Tatsunori Shibuya, Kazuyuki Sakaue, Hiroshi Ogawa, Daisuke Satoh, Thanh-Hung Dinh, Masahiko Ishino, Masahito Tanaka, Masakazu Washio, Takeshi Higashiguchi, Masaharu Nishikino, Akira Kon, Yuya Kubota, Yuichi Inubushi, Shigeki Owada, Yohei Kobayashi, Ryunosuke Kuroda

    Optics Express   29 ( 21 ) 33121 - 33121  2021.10

    DOI

  • Ablation threshold and crater morphology of amorphous and crystalline SiO2 glass for extreme ultraviolet femtosecond pulses

    T. Shibuya, K. Sakaue, H. Ogawa, T.-H. Dinh, D. Satoh, E. Terasawa, M. Washio, M. Tanaka, T. Higashiguchi, M. Ishino, Y. Kubota, Y. Inubushi, S. Owada, M. Nishikino, Y. Kobayashi, R. Kuroda

    Japanese Journal of Applied Physics   59 ( 12 ) 122004 - 122004  2020.12

    DOI

    Scopus

  • Fabrication of thermo-responsive cell-culture membranes with Poly(N-isopropylacrylamide) by electron-beam graft polymerization

    Ryoya Shimura, Yoshitaka Suematsu, Hiroto Horiuchi, Shinji Takeoka, Akihiro Oshima, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   171  2020.06  [Refereed]

     View Summary

    Cell-sheet engineering aims to generate tissues and organs through lamination and transplantation of acquired cell sheets. The technique has become used in the field of regenerative medicine, and the development of cell-culture plates equipped with a switching function for cell adhesion/cell-sheet detachment has been in progress. Our research group has produced thermo-responsive cell-culture membranes by grafting poly(N-isopropylacrylamide) (PNIPAAm) onto an ethylene-tetrafluoroethylene copolymer (ETFE). Grafting is achieved via electron beam (EB) pre-irradiation grafting methods. The high biocompatibility of ETFE is well known, and high yields of trapped radicals can be obtained through the use of ionizing radiation. Increased thermo-responsivity of the cell-culture membranes can be achieved by increasing the amount of grafted PNIPAAm. In the present study, we fabricated grafted membranes with different grafting yields (GY), and evaluated the thermo-responsivity and cell-adhesion/cell-sheet-detachment abilities. First, C2C12 cells were cultured at 37 degrees C for 2 days on the grafted samples, then the cell sheet was detached by reducing the temperature to 20 degrees C after cell proliferation. In the fabricated samples with the GY of 14.9% +/- 1.0%, cells reached confluence in 2 days, and the resulting cell sheet was detached within 15 min without any damage.

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Pulse duration dependence of ablation threshold for fused silica in the visible femtosecond regime

    E. Terasawa, T. Shibuya, D. Satoh, Y. Moriai, H. Ogawa, M. Tanaka, R. Kuroda, Y. Kobayashi, K. Sakaue, M. Washio

    Applied Physics A   126 ( 6 )  2020.06  [Refereed]

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • Soft x-ray laser beamline for surface processing and damage studies.

    Masahiko Ishino, Thanh-Hung Dinh, Yuji Hosaka, Noboru Hasegawa, Kimio Yoshimura, Hiroki Yamamoto, Tadashi Hatano, Takeshi Higashiguchi, Kazuyuki Sakaue, Satoshi Ichimaru, Masatoshi Hatayama, Akira Sasaki, Masakazu Washio, Masaharu Nishikino, Yasunari Maekawa

    Applied optics   59 ( 12 ) 3692 - 3698  2020.04  [International journal]

     View Summary

    We have developed a soft x-ray laser (SXRL) beamline equipped with an intensity monitor dedicated to ablation study such as surface processing and damage formation. The SXRL beam having a wavelength of 13.9 nm, pulse width of 7 ps, and pulse energy of around 200 nJ is generated from Ag plasma mediums using an oscillator-amplifier configuration. The SXRL beam is focused onto the sample surface by the Mo/Si multilayer coated spherical mirror. To get the correct irradiation energy/fluence, an intensity monitor composed of a Mo/Si multilayer beam splitter and an x-ray charge-coupled device camera has been installed in the beamline. The Mo/Si multilayer beam splitter has a large polarization dependence in the reflectivity around the incident angle of 45°. However, by evaluating the relationship between reflectivity and transmittance of the beam splitter appropriately, the irradiation energy onto the sample surface can be derived from the energy acquired by the intensity monitor. This SXRL beamline is available to not only the ablation phenomena but also the performance evaluation of soft x-ray optics and resists.

    DOI PubMed

    Scopus

    1
    Citation
    (Scopus)
  • Quasi-monochromatic THz pulse generation using Cherenkov radiation from a spatially modulated electron beam

    Tadenuma, Y., Murakami, T., Brameld, M., Washio, M., Sakaue, K., Kuroda, R., Taira, Y.

    Journal of Instrumentation    2020

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Development of self-resonating enhancement cavity operating in single-longitudinal-mode

    Yuuki Uesugi, Alexander S. Aryshev, Masafumi Fukuda, Tsunehiko Omori, Nobuhiro Terunuma, Junji Urakawa, Tohru Takahashi, Yuya Koshiba, Seiya Otsuka, Masakazu Washio, Yuji Hosaka, Shunichi Sato

    Conference on Lasers and Electro-Optics    2020

    DOI

  • Mode-locked pulse oscillation of a self-resonating enhancement optical cavity

    Y.Hosaka, Y. Honda, T. Omori, J. Urakawa, A. Kosuge, K. Sakaue, T. Takahashi, Y. Uesugi, M. Washio

    Journal of Physics: Conference Series   1350   1 - 6  2019.12  [Refereed]

  • Controlled strong excitation of silicon as a step towards processing materials at sub-nanometer precision

    Thanh-Hung Dinh, Nikita Medvedev, Masahiko Ishino, Toshiyuki Kitamura, Noboru Hasegawa, Tomohito Otobe, Takeshi Higashiguchi, Kazuyuki Sakaue, Masakazu Washio, Tadashi Hatano, Akira Kon, Yuya Kubota, Yuichi Inubushi, Shigeki Owada, Tatsunori Shibuya, Beata Ziaja, Masaharu Nishikino

    COMMUNICATIONS PHYSICS   2  2019.11

     View Summary

    Interaction of a solid material with focused, intense pulses of high-energy photons or other particles (such as electrons and ions) creates a strong electronic excitation state within an ultra-short time and on ultra-small spatial scales. This offers the possibility to control the response of a material on a spatial scale less than a nanometer-crucial for the next generation of nano-devices. Here we create craters on the surface of a silicon substrate by focusing single femtosecond extreme ultraviolet pulse from the SACLA free-electron laser. We investigate the resulting surface modification in the vicinity of damage thresholds, establishing a connection to microscopic theoretical approaches, and, with their help, illustrating physical mechanisms for damage creation. The cooling during ablation by means of rapid electron and energy transport can suppress undesired hydrodynamical motions, allowing the silicon material to be directly processed with a precision reaching the observable limitation of an atomic force microscope.

    DOI

    Scopus

    15
    Citation
    (Scopus)
  • Study on a long-life photocathode with an CsBr protective layer for an rf electron gun

    Ono Hiroya, Miyamatsu Junya, Tamba Tomoaki, Sakaue Kazuyuki, Washio Masakazu, Iijima Hokuto, Zen Heishun

    JAPANESE JOURNAL OF APPLIED PHYSICS   58 ( 6 )  2019.06  [Refereed]

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Stabilization of burst laser pulse storage in an optical enhancement cavity using a counter propagating mode

    Kazuyuki Sakaue, Masakazu Washio, Sakae Araki, Masafumi Fukuda, Yosuke Honda, Nobuhiro Terunuma, Junji Urakawa

    Review of Scientific Instruments   89 ( 2 )  2018.02

     View Summary

    We describe the stabilization technique of an optical enhancement cavity using a counter propagating mode. The burst amplification of the injection laser in the main path induces a drastic change in the laser intensity and disturbs the stabilization of the enhancement cavity. We have used a counter propagating mode to achieve a 4% intensity jitter and 0.6 mJ pulse storage inside the cavity at the maximum of the burst region. Our results indicate that the counter propagating mode has the same resonant condition as the main mode and thus becomes useful for stabilizing the enhancement cavity. We also determined that the burst amplification brought about no decrease in the enhancement factor in the cavity due to the degradation of laser quality.

    DOI PubMed

    Scopus

    4
    Citation
    (Scopus)
  • Study on Electron-beam-induced Reactions of Methyl alpha-Allyloxymethyl Acrylic Polymer

    Hosaka Yuji, Kondoh Takafumi, Oyama Tomoko Gowa, Uchida Tomoya, Taguchi Mitsumasa, Yoshida Yoichi, Washio Masakazu

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   31 ( 1 ) 85 - 90  2018  [Refereed]

    DOI

    Scopus

  • Fabrication of thermo-responsive PNIPAAm-g-ETFE for cell culture dishes by pre-irradiation grafting

    Yumi Yamahara, Naotsugu Nagasawa, Mitsumasa Taguchi, Akihiro Oshima, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   142   88 - 93  2018.01  [Refereed]

     View Summary

    Thermo-responsive templates for the cell cultivation based on Poly(tetrafluoroethylene-co-ethylene) (ETFE) were fabricated by pre-irradiation grafting of N-isoproplyacrylamide (NIPAAm) monomer by electron beam (EB) irradiation under nitrogen gas atmosphere at room temperature, and their characteristic properties were studied. The detachment of cultured HeLa cells from fabricated thermo-responsive templates were attempted. Furthermore, the reaction mechanism is proposed using ESR spectroscopy and FT-IR spectroscopy.It is confirmed that the cultured HeLa cells were detached from fabricated thermo-responsive templates at 20 degrees C. Water contact angle analysis indicated that obtained templates had thermo-response around 30 degrees C. It is suggested that the grafted polymer chains would mainly react with peroxy radicals (-CF2-CF(OO center dot)-) on tetrafluoroethylene unit in ETFE.

    DOI

    Scopus

    4
    Citation
    (Scopus)
  • Development of optical resonant cavities for laser-Compton scattering

    T. Akagi, S. Araki, Y. Honda, A. Kosuge, T. Omori, H. Shimizu, N. Terunuma, J. Urakawa, T. Takahashi, R. Tanaka, Y. Uesugi, H. Yoshitama, Y. Hosaka, K. Sakaue, M. Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   402   370 - 372  2017.07  [Refereed]

     View Summary

    We have been developing optical resonant cavities for laser-Compton scattering experiment at the Accelerator Test Facility in KEN. The main subject of the R&D is to increase laser pulse energy by coherently accumulating the pulses in an optical resonant cavity. We report previous results, current status and future prospects, including a new idea of an optical resonant cavity. (C) 2017 Elsevier B.V. All rights reserved.

    DOI

    Scopus

  • Improvement of X-ray Generation by Using Laser Compton Scattering in Laser Undulator Compact X-ray Source (LUCX)

    Masafumi Fukuda, Sakae Araki, Yosuke Honda, Kazuyuki Sakaue, Yoske Sumitomo, Nobuhiro Terunuma, Junji Urakawa, Masakazu Washio

    NA-PAC2016 THPOA51    2017.01

     View Summary

    We have been developing a compact X-ray source based on the laser Compton scattering(LCS) at Laser Undulator Compact X-ray source(LUCX) accelerator in KEK. We have started to take X-ray images such as refraction contrast images and phase contrast imaging with Talbot interferometer. In this accelerator, 6-10keV X-rays are generated by LCS. An electron beam is produced by a 3.6cell RF-gun and accelerated to 18-24MeV by a 12cell accelerating tube. A laser pulse is stored in a 4-mirror planar optical cavity to enhance the power. To increase the flux of LCS X-rays, we perform an optimization of the beam-loading compensation, improvement of the intensity of an electron beam and a laser light at the collision point. We report the result of the X-ray generation in this accelerator.

    DOI

  • Contribution of material's surface layer on charge state distribution in laser ablation plasma

    Masafumi Kumaki, Dannie Steski, Shunsuke Ikeda, Takeshi Kanesue, Masahiro Okamura, Masakazu Washio

    REVIEW OF SCIENTIFIC INSTRUMENTS   87 ( 2 )  2016.02  [Refereed]

     View Summary

    To generate laser ablation plasma, a pulse laser is focused onto a solid target making a crater on the surface. However, not all the evaporated material is efficiently converted to hot plasma. Some portion of the evaporated material could be turned to low temperature plasma or just vapor. To investigate the mechanism, we prepared an aluminum target coated by thin carbon layers. Then, we measured the ablation plasma properties with different carbon thicknesses on the aluminum plate. The results showed that C6+ ions were generated only from the surface layer. The deep layers (over 250 nm from the surface) did not provide high charge state ions. On the other hand, low charge state ions were mainly produced by the deeper layers of the target. Atoms deeper than 1000 nm did not contribute to the ablation plasma formation. (C) 2016 AIP Publishing LLC.

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • 22aAP-3 Development of Compact X-ray Source with a Pulsed Laser Cavity in LUCX (18)

    Fukuda M, Araki S, Sakaue K, Terunuma N, Urakawa J, Washio M, Honda Y

    Meeting Abstracts of the Physical Society of Japan   71 ( 0 ) 601 - 601  2016

    DOI CiNii

  • 22aAP-8 Development of an EO sampling method for THz pulse detection

    Toida T, Suzuki R, Yanagisawa R, Sakaue K, Washio M

    Meeting Abstracts of the Physical Society of Japan   71 ( 0 ) 606 - 606  2016

    DOI CiNii

  • 20pAF-7 Study on bialkali photocathode for the RF electron gun at Waseda University

    Ono H, Matsuzaki S, Washio M, Sakaue K, Iijima H

    Meeting Abstracts of the Physical Society of Japan   71 ( 0 ) 575 - 575  2016

    DOI CiNii

  • 22aAP-7 Study on THz imaging by using coherent Cherenkov radiation

    Nishida M, Mizugaki M, Washio M, Sakaue K, Kuroda R, Taira Y

    Meeting Abstracts of the Physical Society of Japan   71 ( 0 ) 605 - 605  2016

    DOI CiNii

  • 22aAP-8 Development of an EO sampling method for THz pulse detection

    Toida T, Suzuki R, Yanagisawa R, Sakaue K, Washio M

    Meeting Abstracts of the Physical Society of Japan   71 ( 0 ) 606 - 606  2016

    DOI CiNii

  • 20pAF-7 Study on bialkali photocathode for the RF electron gun at Waseda University

    Ono H, Matsuzaki S, Washio M, Sakaue K, Iijima H

    Meeting Abstracts of the Physical Society of Japan   71 ( 0 ) 575 - 575  2016

    DOI CiNii

  • 19aAQ-9 Development of pulse radiolysis system by introducing femtosecond fiber laser

    Soeta Y, Saito Y, Ito Y, Hosaka Y, Sakaue K, Washio M

    Meeting Abstracts of the Physical Society of Japan   71 ( 0 ) 561 - 561  2016

    DOI CiNii

  • 22aAP-7 Study on THz imaging by using coherent Cherenkov radiation

    Nishida M, Mizugaki M, Washio M, Sakaue K, Kuroda R, Taira Y

    Meeting Abstracts of the Physical Society of Japan   71 ( 0 ) 605 - 605  2016

    DOI CiNii

  • 22aAP-3 Development of Compact X-ray Source with a Pulsed Laser Cavity in LUCX (18)

    Fukuda M, Araki S, Sakaue K, Terunuma N, Urakawa J, Washio M, Honda Y

    Meeting Abstracts of the Physical Society of Japan   71 ( 0 ) 601 - 601  2016

    DOI CiNii

  • 19aAQ-9 Development of pulse radiolysis system by introducing femtosecond fiber laser

    Soeta Y, Saito Y, Ito Y, Hosaka Y, Sakaue K, Washio M

    Meeting Abstracts of the Physical Society of Japan   71 ( 0 ) 561 - 561  2016

    DOI CiNii

  • Generation of low-flux X-ray micro-planar beams and their biological effect on a murine subcutaneous tumor model.

    Hong Z, Zenkoh J, Le B, Gerelchuluun A, Suzuki K, Moritake T, Washio M, Urakawa J, Tsuboi K

    Journal of radiation research   56 ( 5 ) 768 - 776  2015.09  [Refereed]  [International journal]

     View Summary

    We generated low-flux X-ray micro-planar beams (MPBs) using a laboratory-scale industrial X-ray generator (60 kV/20 mA) with custom-made collimators with three different peak/pitch widths (50/200 μm, 100/400 μm, 50/400 μm). To evaluate normal skin reactions, the thighs of C3H/HeN mice were exposed to 100 and 200 Gy MPBs in comparison with broad beams (20, 30, 40, 50, 60 Gy). Antitumor effects of MPBs were evaluated in C3H/HeN mice with subcutaneous tumors (SCCVII). After the tumors were irradiated with 100 and 200 Gy MPBs and 20 and 30 Gy broad beams, the tumor sizes were measured and survival analyses were performed. In addition, the tumors were excised and immunohistochemically examined to detect γ-H2AX, ki67 and CD34. It was shown that antitumor effects of 200 Gy MPBs at 50/200 μm and 100/400 μm were significantly greater than those of 20 Gy broad beams, and were comparable with 30 Gy broad beams. γ-H2AX-positive cells demonstrated clear stripe-patterns after MPB irradiation; the pattern gradually faded and intermixed over 24 h. The chronological changes in ki67 positivity did not differ between MPBs and broad beams, whereas the CD34-positive area decreased significantly more in MPBs than in broad beams. In addition, it was shown that skin injury after MPB irradiation was significantly milder when compared with broad-beam irradiation at equivalent doses for achieving the same tumor control effect. Bystander effect and tumor vessel injury may be the mechanism contributing to the efficacy of MPBs.

    DOI PubMed

    Scopus

    2
    Citation
    (Scopus)
  • Generation of low-flux X-ray micro-planar beams and their biological effect on a murine subcutaneous tumor model

    Zhengshan Hong, Junko Zenkoh, Biao Le, Ariungerel Gerelchuluun, Kenshi Suzuki, Takashi Moritake, Masakazu Washio, Junji Urakawa, Koji Tsuboi

    Journal of Radiation Research   56 ( 5 ) 768 - 776  2015.09

     View Summary

    We generated low-flux X-ray micro-planar beams (MPBs) using a laboratory-scale industrial X-ray generator (60 kV/20 mA) with custom-made collimators with three different peak/pitch widths (50/200 μm, 100/400 μm, 50/400 μm). To evaluate normal skin reactions, the thighs of C3H/HeN mice were exposed to 100 and 200 Gy MPBs in comparison with broad beams (20, 30, 40, 50, 60 Gy). Antitumor effects of MPBs were evaluated in C3H/HeN mice with subcutaneous tumors (SCCVII). After the tumors were irradiated with 100 and 200 Gy MPBs and 20 and 30 Gy broad beams, the tumor sizes were measured and survival analyses were performed. In addition, the tumors were excised and immunohistochemically examined to detect γ-H2AX, ki67 and CD34. It was shown that antitumor effects of 200 Gy MPBs at 50/200 μm and 100/400 μm were significantly greater than those of 20 Gy broad beams, and were comparable with 30 Gy broad beams. γ-H2AX-positive cells demonstrated clear stripe-patterns after MPB irradiation
    the pattern gradually faded and intermixed over 24 h. The chronological changes in ki67 positivity did not differ between MPBs and broad beams, whereas the CD34-positive area decreased significantly more in MPBs than in broad beams. In addition, it was shown that skin injury after MPB irradiation was significantly milder when compared with broad-beam irradiation at equivalent doses for achieving the same tumor control effect. Bystander effect and tumor vessel injury may be the mechanism contributing to the efficacy of MPBs.

    DOI PubMed

    Scopus

    2
    Citation
    (Scopus)
  • Generation of radially polarized high energy mid-infrared optical vortex by use of a passive axially symmetric ZnSe waveplate

    Toshitaka Wakayama, Hiroki Oikawa, Atsushi Sasanuma, Goki Arai, Yusuke Fujii, Thanh-Hung Dinh, Takeshi Higashiguchi, Kazuyuki Sakaue, Masakazu Washio, Taisuke Miura, Akihiko Takahashi, Daisuke Nakamura, Tatsuo Okada, Motoki Yonemura, Yukitoshi Otani

    APPLIED PHYSICS LETTERS   107 ( 8 )  2015.08  [Refereed]

     View Summary

    We demonstrated the generation of the intense radially polarized mid-infrared optical vortex at a wavelength of 10.6 mu m by use of a passive axially symmetric zinc selenide (ZnSe) waveplate with high energy pulse throughput. The phase of the radially polarized optical vortex with the degree of polarization of 0.95 was spirally distributed in regard to the angle. The converted laser beam energy of about 2.6 mJ per pulse was obtained at the input pulse energy of 4.9 mJ, corresponding to the energy conversion efficiency of 56%. (C) 2015 AIP Publishing LLC.

    DOI

    Scopus

    6
    Citation
    (Scopus)
  • Space Charges Remaining in Polymers after Electron Beam Irradiation and the Role of Conductivity in Their Decay Profiles

    Naoto Tomite, Yukitaka Arai, Yoshimichi Ohki, Toru Hinata, Masakazu Washio

    IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING   10 ( 3 ) 237 - 241  2015.05  [Refereed]

     View Summary

    Five typical insulating polymers and a carbon-loaded polyethylene were irradiated with 200-keV electrons, and the space charge distributions remaining in the polymers were measured. When the polymer film is short-circuited after irradiation, the amount of space charge gradually decreases monotonically. By analyzing such decay profiles, it becomes clear that the decay of the charges remaining after the irradiation is governed by the conductivity of the polymer. (c) 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Determination of the polarization states of an arbitrary polarized terahertz beam: Vectorial vortex analysis

    Toshitaka Wakayama, Takeshi Higashiguchi, Hiroki Oikawa, Kazuyuki Sakaue, Masakazu Washio, Motoki Yonemura, Toru Yoshizawa, J. Scott Tyo, Yukitoshi Otani

    SCIENTIFIC REPORTS   5  2015.03  [Refereed]

     View Summary

    Vectorial vortex analysis is used to determine the polarization states of an arbitrarily polarized terahertz (0.1-1.6 THz) beam using THz achromatic axially symmetric wave (TAS) plates, which have a phase retardance of Delta = 163 degrees and are made of polytetrafluorethylene. Polarized THz beams are converted into THz vectorial vortex beams with no spatial or wavelength dispersion, and the unknown polarization states of the incident THz beams are reconstructed. The polarization determination is also demonstrated at frequencies of 0.16 and 0.36 THz. The results obtained by solving the inverse source problem agree with the values used in the experiments. This vectorial vortex analysis enables a determination of the polarization states of the incident THz beam from the THz image. The polarization states of the beams are estimated after they pass through the TAS plates. The results validate this new approach to polarization detection for intense THz sources. It could find application in such cutting edge areas of physics as nonlinear THz photonics and plasmon excitation, because TAS plates not only instantaneously elucidate the polarization of an enclosed THz beam but can also passively control THz vectorial vortex beams.

    DOI PubMed

    Scopus

    22
    Citation
    (Scopus)
  • Determination of the polarization states of an arbitrary polarized terahertz beam: Vectorial vortex analysis

    Toshitaka Wakayama, Takeshi Higashiguchi, Hiroki Oikawa, Kazuyuki Sakaue, Masakazu Washio, Motoki Yonemura, Toru Yoshizawa, J. Scott Tyo, Yukitoshi Otani

    SCIENTIFIC REPORTS   5  2015.03  [Refereed]

     View Summary

    Vectorial vortex analysis is used to determine the polarization states of an arbitrarily polarized terahertz (0.1-1.6 THz) beam using THz achromatic axially symmetric wave (TAS) plates, which have a phase retardance of Delta = 163 degrees and are made of polytetrafluorethylene. Polarized THz beams are converted into THz vectorial vortex beams with no spatial or wavelength dispersion, and the unknown polarization states of the incident THz beams are reconstructed. The polarization determination is also demonstrated at frequencies of 0.16 and 0.36 THz. The results obtained by solving the inverse source problem agree with the values used in the experiments. This vectorial vortex analysis enables a determination of the polarization states of the incident THz beam from the THz image. The polarization states of the beams are estimated after they pass through the TAS plates. The results validate this new approach to polarization detection for intense THz sources. It could find application in such cutting edge areas of physics as nonlinear THz photonics and plasmon excitation, because TAS plates not only instantaneously elucidate the polarization of an enclosed THz beam but can also passively control THz vectorial vortex beams.

    DOI

    Scopus

    22
    Citation
    (Scopus)
  • Temporal profile measurement of an electron bunch with the two-cell rf deflecting cavity at Waseda University

    Kazuyuki Sakaue, Yuichi Nishimura, Masahiro Nishiyama, Takenoshin Takahashi, Masakazu Washio, Toshikazu Takatomi, Junji Urakawa

    JAPANESE JOURNAL OF APPLIED PHYSICS   54 ( 2 )  2015.02  [Refereed]

     View Summary

    Our group at Waseda University developed an rf deflector system for measuring longitudinal. In this study we evaluated the temporal resolution of an S-band two-cell rf deflector cavity built into the system and performed a series of longitudinal profile measurements of electron bunch from an rf photocathode gun. The if deflector system achieved a temporal resolution of 147.6 fs (rms), the value gave in close agreement with the design specification. We present our experimental results and discussion how the temporal profile was influenced by the if electric field and space charge effect in the electron bunch from the if photo cathode gun. Our results agreed with the results of a beam tracking simulation. The successful results of longitudinal profile measurements in this study confirm that our deflector system will be quite useful for improving an rf electron gun cavities. (C) 2015 The Japan Society of Applied Physics

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • Temporal profile measurement of an electron bunch with the two-cell rf deflecting cavity at Waseda University

    Sakaue Kazuyuki, Nishimura Yuichi, Nishiyama Masahiro, Takahashi Takenoshin, Washio Masakazu, Takatomi Toshikazu, Urakawa Junji

    Jpn. J. Appl. Phys.   54 ( 2 )  2015.01

     View Summary

    Our group at Waseda University developed an rf deflector system for measuring longitudinal. In this study we evaluated the temporal resolution of an S-band two-cell rf deflector cavity built into the system and performed a series of longitudinal profile measurements of electron bunch from an rf photocathode gun. The rf deflector system achieved a temporal resolution of 147.6 fs (rms), the value gave in close agreement with the design specification. We present our experimental results and discussion how the temporal profile was influenced by the rf electric field and space charge effect in the electron bunch from the rf photo cathode gun. Our results agreed with the results of a beam tracking simulation. The successful results of longitudinal profile measurements in this study confirm that our deflector system will be quite useful for improving an rf electron gun cavities.

    CiNii

  • Terahertz polarization determination by passive control of vectorial vortex beam

    T. Wakayama, M. Yonemura, T. Higashiguchi, H. Oikawa, K. Sakaue, M. Washio, T. Yoshizavva, J. S. Tyo, Y. Otani

    2015 PHOTONICS CONFERENCE (IPC)     228 - 229  2015  [Refereed]

     View Summary

    We demonstrate Terahertz polarization determination by the passive control of THz vectorial vortex (TVV) beams which is achieved from a THz achromatic-axially symmetric waveplate (TAS) based on total internal reflection in the 0.1-1.6 THz region. The polarization determination is demonstrated by analyzing the spatial intensity distribution in a THz image, and is applied two different THz sourees at 0.16 and 0.36 THz, experimentally. Consider the inverse problem of linear system, it is also possible to determine the angularly variant polarization of TVV beam after passing through TAS plate.

    DOI

    Scopus

  • Positive-negative dual-tone sensitivities of ZEP resist

    Tomoko Gowa Oyama, Hirotaka Nakamura, Akihiro Oshima, Masakazu Washio, Seiichi Tagawa

    APPLIED PHYSICS EXPRESS   7 ( 3 )  2014.03  [Refereed]

     View Summary

    A chlorinated resist named ZEP changes from positive- to negative-tone with a high dose of electron beam irradiation. The sensitivities to a 100-kV electron beam as a dual positive- and negative-tone resist are evaluated with various developers. Although the positive-tone sensitivity varies with different developers owing to different solvation strengths, the threshold dose for the positive negative (P-N) inversion is independent of the developer. According to an analysis using X-ray photoelectron spectroscopy and NMR spectroscopy, the amount of chlorine atoms and terminal double bonds generated by chain scission determines the scission/crosslinking probabilities, i.e., the threshold of the P-N inversion. (C) 2014 The Japan Society of Applied Physics

    DOI

    Scopus

    4
    Citation
    (Scopus)
  • 27aTM-8 Development of a direct profile measurement technique of high power laser focal spot by a high quality electron beam

    Sato Ryo, Yoshida Yasushi, Nonomura Kou, Sakaue Kazuyuki, Endo Akira, Washio Masakazu

    Meeting abstracts of the Physical Society of Japan   69 ( 1 ) 138 - 138  2014.03

    CiNii

  • Analyses of the plasma generated by laser irradiation on sputtered target for determination of the thickness used for plasma generation

    Masafumi Kumaki, Shunsuke Ikeda, Yasuhiro Fuwa, David Cinquegrani, Megumi Sekine, Naoya Munemoto, Takeshi Kanesue, Masahiro Okamura, Masakazu Washio

    Review of Scientific Instruments   85 ( 2 )  2014.02

     View Summary

    In Brookhaven National Laboratory, laser ion source has been developed to provide heavy ion beams by using plasma generation with 1064 nm Nd:YAG laser irradiation onto solid targets. The laser energy is transferred to the target material and creates a crater on the surface. However, only the partial material can be turned into plasma state and the other portion is considered to be just vaporized. Since heat propagation in the target material requires more than typical laser irradiation period, which is typically several ns, only the certain depth of the layers may contribute to form the plasma. As a result, the depth is more than 500 nm because the base material Al ions were detected. On the other hand, the result of comparing each carbon thickness case suggests that the surface carbon layer is not contributed to generate plasma. © 2014 AIP Publishing LLC.

    DOI

    Scopus

    6
    Citation
    (Scopus)
  • Analyses of the plasma generated by laser irradiation on sputtered target for determination of the thickness used for plasma generation

    Masafumi Kumaki, Shunsuke Ikeda, Yasuhiro Fuwa, David Cinquegrani, Megumi Sekine, Naoya Munemoto, Takeshi Kanesue, Masahiro Okamura, Masakazu Washio

    REVIEW OF SCIENTIFIC INSTRUMENTS   85 ( 2 )  2014.02  [Refereed]

     View Summary

    In Brookhaven National Laboratory, laser ion source has been developed to provide heavy ion beams by using plasma generation with 1064 nm Nd:YAG laser irradiation onto solid targets. The laser energy is transferred to the target material and creates a crater on the surface. However, only the partial material can be turned into plasma state and the other portion is considered to be just vaporized. Since heat propagation in the target material requires more than typical laser irradiation period, which is typically several ns, only the certain depth of the layers may contribute to form the plasma. As a result, the depth is more than 500 nm because the base material Al ions were detected. On the other hand, the result of comparing each carbon thickness case suggests that the surface carbon layer is not contributed to generate plasma. (C) 2014 AIP Publishing LLC.

    DOI

    Scopus

    6
    Citation
    (Scopus)
  • Optimization of X-ray microplanar beam radiation therapy for deep-seated tumors by a simulation study.

    Shinohara Kunio, Kondoh Takeshi, Nariyama Nobuteru, Fujita Hajime, Washio Masakazu, Aoki Yukimasa

    Optimization of X-ray microplanar beam radiation therapy for deep-seated tumors by a simulation study.   22 ( 3 )  2014

     View Summary

    :A Monte Carlo simulation was applied to study the energy dependence on the transverse dose distribution of microplanar beam radiation therapy (MRT) for deep-seated tumors. The distribution was found to be the peak (in-beam) dose and the decay from the edge of the beam down to the valley. The area below the same valley dose level (valley region) was decreased with the increase in the energy of X-rays at the same beam separation. To optimize the MRT, we made the following two assumptions: the therapeutic gain may be attributed to the efficient recovery of normal tissue caused by the beam separation; and a key factor for the efficient recovery of normal tissue depends on the area size of the valley region. Based on these assumptions and the results of the simulated dose distribution, we concluded that the optimum X-ray energy was in the range of 100-300 keV depending on the effective peak dose to the target tumors and/or tolerable surface dose. In addition, we proposed parameters to be studied for the optimization of MRT to deep-seated tumors.

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • Optimization of X-ray microplanar beam radiation therapy for deep-seated tumors by a simulation study

    Kunio Shinohara, Takeshi Kondoh, Nobuteru Nariyama, Hajime Fujita, Masakazu Washio, Yukimasa Aoki

    JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY   22 ( 3 ) 395 - 406  2014  [Refereed]

     View Summary

    A Monte Carlo simulation was applied to study the energy dependence on the transverse dose distribution of microplanar beam radiation therapy (MRT) for deep-seated tumors. The distribution was found to be the peak (in-beam) dose and the decay from the edge of the beam down to the valley. The area below the same valley dose level (valley region) was decreased with the increase in the energy of X-rays at the same beam separation. To optimize the MRT, we made the following two assumptions: the therapeutic gain may be attributed to the efficient recovery of normal tissue caused by the beam separation; and a key factor for the efficient recovery of normal tissue depends on the area size of the valley region. Based on these assumptions and the results of the simulated dose distribution, we concluded that the optimum X-ray energy was in the range of 100-300 keV depending on the effective peak dose to the target tumors and/or tolerable surface dose. In addition, we proposed parameters to be studied for the optimization of MRT to deep-seated tumors.

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • Study on direct etching of poly(tetrafluoroethylene) by high-energy heavy ion beams

    Hidehiro Tsubokura, Akihiro Oshima, Tomoko G. Oyama, Yuya Takasawa, Naoyuki Fukutake, Satoshi Okubo, Taeko Yoshikawa, Toshitaka Oka, Takeshi Murakami, Yoshimasa Hama, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   92   37 - 42  2013.11  [Refereed]

     View Summary

    Micro-fabrication of poly(tetrafluoroethylene) (PTFE) was carried out using a high-energy heavy ion beam in the MeV region. PTFE was irradiated with various ions (6 MeV/u) under vacuum (< 1.0 x 10(-4) Pa) at room temperature (298 K). The surface of the irradiated PTFE was observed by laser microscopy and a scanning electron microscope (SEM). Micro-scale fabrications of PTFE were successfully performed by direct ion beam etching. Under our experimental conditions the etching proceeded more effectively by heavy ion beams (larger than N7+), compared with lower-energy ion beams (key region). A larger atomic number (Z) of the irradiating ion induced higher etching rates in PTFE; the etching rate for Ne10+ and Xe54+ changed from 6.5 x 10(-13) to 2.0 x 10(-11) mu m/(ion cm(-2)), respectively. As a result we suggest that due to their high electronic stopping powers, etching could be efficiently achieved using high-energy ion beams. (C) 2013 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • Micro/nanofabrication of poly((L)-lactic acid) using focused ion beam direct etching

    Tomoko Gowa Oyama, Toru Hinata, Naotsugu Nagasawa, Akihiro Oshima, Masakazu Washio, Seiichi Tagawa, Mitsumasa Taguchi

    APPLIED PHYSICS LETTERS   103 ( 16 )  2013.10

     View Summary

    Micro/nanofabrication of biocompatible and biodegradable poly(L-lactic acid) (PLLA) using focused Ga ion beam direct etching was evaluated for future bio-device applications. The fabrication performance was determined with different ion fluences and fluxes (beam currents), and it was found that the etching speed and fabrication accuracy were affected by irradiation-induced heat. Focused ion beam (FIB)-irradiated surfaces were analyzed using micro-area X-ray photoelectron spectroscopy. Owing to reactions such as the physical sputtering of atoms and radiation-induced decomposition, PLLA was gradually carbonized with increasing C = C bonds. Controlled micro/nanostructures of PLLA were fabricated with C = C bond-rich surfaces expected to have good cell attachment properties. (C) 2013 AIP Publishing LLC.

    DOI

    Scopus

    12
    Citation
    (Scopus)
  • Fabrication of function-graded proton exchange membranes by electron beam irradiation for polymer electrolyte fuel cells under nonhumidified condition

    Ryota Tsuchida, Atsushi Tsukamoto, Satoshi Hiraiwa, Akihiro Oshima, Masakazu Washio

    JOURNAL OF POWER SOURCES   240   351 - 358  2013.10  [Refereed]

     View Summary

    Function-graded proton exchange membranes (G-PEMs) for polymer electrolyte fuel cells (PEFCs) are fabricated by electron beam (EB) grafting using a heterogeneous energy deposition technique. The fabricated G-PEMs have a water uptake gradient in the direction of the thickness originating from the sulfonic acid group gradient. Normal PEMs (N-PEMs), which have almost no gradient ionic groups in the membrane, are also fabricated to compare with G-PEMs. PEFC operations for comparing the fabricated G-PEMs, normal PEMs (N-PEMs), and Nafion (R) 212 are carried out at 30 degrees C and 60 degrees C with dry H-2/O-2 gases. It is expected that the advantages of using dry fuel gases are lower cost and a smaller size system than that is possible with a humid fuel. The fabricated G-PEMs show a higher power density than Nafion (R) 212 and N-PEMs at 30 degrees C, and the deterioration of the performance of fabricated G-PEMs is lower than that of Nafion (R) 212. These results are thought to be caused by the difference in proton transfer kinetics between the fabricated G-PEMs and those of Nafion (R) 212. It is therefore considered that G-PEMs not only exhibit higher performance at low temperature under nonhumidified conditions but also cost less than Nafion (R) 212. (c) 2013 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • Method of predicting resist sensitivity for 6.x nm extreme ultraviolet lithography

    Tomoko Gowa Oyama, Akihiro Oshima, Masakazu Washio, Seiichi Tagawa

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B   31 ( 4 )  2013.07  [Refereed]

     View Summary

    Potential extension of 13.5 nm extreme ultraviolet lithography (EUVL) to the soft x-ray region in the 6.x nm range (6.6-6.8 nm) has been discussed recently in academia and the semiconductor industry in terms of the light source, optics, and resist performance. In this study, the authors investigated the precise sensitivities of several resists (both nonchemically amplified and chemically amplified resists) using highly monochromatized soft x rays from synchrotron radiation with accurate dosimetry. The selected wavelengths included 6.7 nm, which is one of the candidates for 6.x nm EUVL. Each obtained "dose/sensitivity, E (mJ cm(-2))" was converted into the " absorbed dose, D (absorbed energy per unit mass, Gray; Gy = J kg(-1))" in terms of radiation and nuclear science. Although the absorbed dose in a resist film depends on the distance from the top surface of the resist, the required absorbed doses (D-0 or D-50) corresponding to the dose/sensitivities (E-0 or E-50) were almost constant for each resist, regardless of the exposure wavelength from 3.1 to 6.7 nm. This would be applicable in the EUV/soft x-ray region, where nearly the same chemical reactions are induced. According to the obtained results, the resist sensitivities for any exposure wavelength in the EUV/soft x-ray region can be predicted easily by using the sensitivity that is measured at a certain wavelength, the resist's thickness, and the linear absorption coefficients that can be calculated using the chemical composition and density of a resist. The resist sensitivity at 6.x nm can be predicted by evaluating the sensitivity using a conventional 13.5 nm EUV exposure tool. Moreover, this prediction method can be used for dose calibration of a simplified EUV exposure tool by utilizing a resist sensitivity that is obtained for a calibrated exposure source. (C) 2013 American Vacuum Society.

    DOI

    Scopus

    8
    Citation
    (Scopus)
  • Construction of nanosecond and picosecond pulse radiolysis system with supercontinuum probe

    Yuji Hosaka, Ryosuke Betto, Kazuyuki Sakaue, Ryunosuke Kuroda, Shigeru Kashiwagi, Kiminori Ushida, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   84   10 - 13  2013.03  [Refereed]

     View Summary

    Supercontinuum (SC) with photonic crystal fiber (PCF) is a new technique of pulsed white light generation. The pump beam and the white probe light are necessary for pump-probe pulse radiolysis. The improvement of pulse radiolysis system can be expected by using PCF based SC as probe light. The source size of white light that depends on core size of PCF will be improved. Nanosecond time resolution pulse radiolysis with SC probe was successfully conducted about pure water sample. The absorption decay and spectrum of hydrated electron was obtained. As SC is a short pulse, it would be applicable for picosecond time resolution pulse radiolysis based on the stroboscopic method. (c) 2012 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    15
    Citation
    (Scopus)
  • 放射線の有用性の啓発へ向けて

    鷲尾 方一

    Isotope news   ( 706 )  2013.02

    CiNii

  • Method of predicting resist sensitivity for 6.x nm extreme ultraviolet lithography

    Oyama, Tomoko Gowa, Oshima, Akihiro, Washio, Masakazu, Tagawa, Seiichi

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B   31 ( 4 )  2013

    DOI

    Scopus

    8
    Citation
    (Scopus)
  • Pulse Radiolysis Study on a Highly Sensitive Chlorinated Resist ZEP520A

    Yuji Hosaka, Tomoko Gowa Oyama, Akihiro Oshima, Satoshi Enomoto, Masakazu Washio, Seiichi Tagawa

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   26 ( 6 ) 745 - 750  2013  [Refereed]

     View Summary

    ZEP520A is one of the most popular positive electron beam (EB) resists used in research and photomask fabrication owing to its good spatial resolution, high sensitivity, and high dry etching resistance. Herein, EB-induced early reactions of ZEP520A were investigated via pulse radiolysis. Dissociative electron attachment and formation of a charge transfer complex were definitive contributing factors to the efficient degradation of ZEP520A. Furthermore, products induced by direct ionization of ZEP520A were observed in a highly concentrated ZEP520A solution in tetrahydrofuran, suggesting that early reactions in the ZEP520A solid film that were induced only by direct ionization could be simulated during pulse radiolysis in specific solutions.

    DOI

    Scopus

    11
    Citation
    (Scopus)
  • Thermal and radiation process for nano-/micro-fabrication of crosslinked PTFE

    Akinobu Kobayashi, Akihiro Oshima, Satoshi Okubo, Hidehiro Tsubokura, Tomohiro Takahashi, Tomoko Gowa Oyama, Seiichi Tagawa, Masakazu Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   295   76 - 80  2013.01  [Refereed]

     View Summary

    Nano-/micro-fabrication process of crosslinked poly(tetrafluoroethylene) (RX-PTFE) is proposed as a novel method using combined process which is thermal and radiation process for fabrication of RX-PTFE (TRaf process). Nano- and micro-scale patterns of silicon wafers fabricated by EB lithography were used as the molds for TRaf process. Poly(tetrafluoroethylene) (PTFE) dispersion was dropped on the fabricated molds, and then PTFE was crosslinked with doses from 105 kGy to 1500 kGy in its molten state at 340 degrees C in nitrogen atmosphere. The obtained nano- and micro-structures by TRaf process were compared with those by the conventional thermal fabrication process. Average surface roughness (R-a) of obtained structures was evaluated with atomic force microscope (AFM) and scanning electron microscope (SEM). R-a of obtained structures with the crosslinking dose of 600 kGy showed less than 1.2 nm. The fine nano-/micro-structures of crosslinked PTFE were successfully obtained by TRaf process. (C) 2012 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    4
    Citation
    (Scopus)
  • Fabrication of nanobeads from nanocups by controlling scission/crosslinking in organic polymer materials

    Tomoko Gowa Oyama, Akihiro Oshima, Masakazu Washio, Seiichi Tagawa

    NANOTECHNOLOGY   23 ( 49 )  2012.12  [Refereed]

     View Summary

    The development of several kinds of micro/nanofabrication techniques has resulted in many innovations in the micro/nanodevices that support today's science and technology. With feature miniaturization, the fabrication tools have shifted from light to ionizing radiation. Here, we propose a simple micro/nanofabrication technique for organic materials using a scanning beam (SB) of ionizing radiation. By controlling the scission/crosslinking of the material via three-dimensional energy-deposition distribution of the SB, appropriate solvents can easily peel off only the crosslinked region from the bulk material. The technique was demonstrated using a focused ion beam and a chlorinated organic polymer. The polymer underwent main-chain scission upon irradiation, but it crosslinked after high-dose irradiation. Appropriate solvents could easily peel off only the crosslinked region from the bulk material. The technique, 'nanobead from nanocup', enabled the production of desired structures such as nanowires and nanomembranes. It can be also applied to the micro/nanofabrication of functional materials.

    DOI

    Scopus

    6
    Citation
    (Scopus)
  • ESR study for ion beam induced phenomena in poly (tetrafluoroethylene-co-hexafluoropropylene) (FEP)

    Taeko Yoshikawa, Akihiro Oshima, Takeshi Murakami, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   81 ( 12 ) 1904 - 1909  2012.12  [Refereed]

     View Summary

    Trapped radicals induced in poly (tetrafluoroethylene-co-hexafiuoropropylene) (FEP) were observed by X-band electron spin resonance (ESR) spectroscopy at room temperature (RT) under atmospheric field after an irradiation with various kinds of high energy ion beams (6 MeV/u). The irradiation was carried out to a stacked FEP films under vacuum (< 4E-4 Pa) at RT with various fluences from 1.0 x 10(9) to 1.0 x 10(11) ions/cm(2). All ESR spectra indicated an existence of peroxy radicals in each of the FEP films without any relation to a kind of ion and a penetration depth. Obtained depth profiles of radical concentrations induced with each ion beam almost correspond to those of stopping power. The trapped radical concentrations were strongly dependent on stopping power. It was found that G-value of trapped radicals by ion beam irradiation was decreased with increasing a stopping power, and was less than the case of gamma-rays irradiation. (C) 2012 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • Nano- and micro-fabrications of polystyrene having atactic and syndiotactic structures using focused ion beams lithography

    Akihiro Oshima, Satoshi Okubo, Tomoko Gowa Oyama, Masakazu Washio, Seiichi Tagawa

    RADIATION PHYSICS AND CHEMISTRY   81 ( 5 ) 584 - 588  2012.05  [Refereed]

     View Summary

    Micro- and nano-fabrications of polystyrene (PS) having the atactic and syndiotactic structures were carried out with direct maskless etching using focused ion beam (FIB). Micro- and nano-scale structures were obtained with selective beam and material conditions avoiding the beam-heating and charge-up effects. The etching rates were different between atactic and syndiotactic PS. The rate of fabrication for syndiotactic PS shows higher than that of atactic one. Moreover, the direct etching was influenced by the molecular weight. The etching rate for the lower molecular weight became the faster. The FIB direct etching proceeds through the two steps (decomposition and desorption (outgas)). Both decomposition and desorption are influenced by both conformation (morphology) and configuration (stereoregularity). Furthermore, the beam profiles and fluence play the important roles to perform the nano-fabrication of PS. (C) 2011 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • Design of high brightness laser-Compton source for extreme ultraviolet and soft x-ray wavelengths

    Kazuyuki Sakaue, Akira Endo, Masakazu Washio

    JOURNAL OF MICRO-NANOLITHOGRAPHY MEMS AND MOEMS   11 ( 2 )  2012.04  [Refereed]

     View Summary

    Design of a clean, high-brightness light source is presented for extreme ultraviolet/ soft x-ray (EUV/SXR) lithography research and mask inspection. Basic characteristics of classical laser-Compton scattering are reviewed, and the laser and electron beam parameters at relatively low energy (EUV to SXR) photon generation are optimized. Recent achievements in each component technology are evaluated on a continuous wave (CW)-operated electron linac and energy recovery linac system, based on superconducting technologies at a 1.3 GHz operation frequency, 10 kW average power, short pulse CO2 laser, and optical super cavity with a 600-enhancement- factor at 10.6 mu m wavelength. Combining both the CW electron beam and short pulse CO2 laser with super-cavity enhancement, 1 mW/2% b.w. flux and 30 kW/mm(2)/sr/2% b.w. brightness laser-Compton source is designed at 6.7-nm wavelength. The technological gap in the present component technologies are discussed, as well as any further required developments. (c) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JMM.11.2.021124]

    DOI

  • Electron-Beam-Induced Decomposition Mechanisms of High-Sensitivity Chlorinated Resist ZEP520A

    Tomoko Gowa Oyama, Kazuyuki Enomoto, Yuji Hosaka, Akihiro Oshima, Masakazu Washio, Seiichi Tagawa

    APPLIED PHYSICS EXPRESS   5 ( 3 )  2012.03  [Refereed]

     View Summary

    ZEP520A (1:1 copolymer of alpha-chloromethacrylate and alpha-methylstyrene, ZEON) is a main-chain scission-type positive-tone resist used for electron beam (EB) lithography and is known for its high sensitivity and high resolution. In this study, ZEP520A was irradiated using a 100 kV EB, and the decomposition mechanisms were analyzed by gel permeation chromatography, Fourier transform IR spectroscopy, NMR spectroscopy, and pulse radiolysis. Chlorines were confirmed to easily dissociate as Cl- ions (dissociative electron attachment, DEA) and ZEP520A underwent beta-scission. Multiple channels could be considered for the main-chain scission, including DEA and the charge transfer complex between phenyl radical cations and Cl- ions. (C) 2012 The Japan Society of Applied Physics

    DOI

    Scopus

    19
    Citation
    (Scopus)
  • Micro-/Nanofabrication of Cross-linked Poly(L-lactic acid) Using Electron Beam Nanoimprint Lithography

    Satoshi Okubo, Naotsugu Nagasawa, Akinobu Kobayashi, Tomoko Gowa Oyama, Mitsumasa Taguchi, Akihiro Oshima, Seiichi Tagawa, Masakazu Washio

    APPLIED PHYSICS EXPRESS   5 ( 2 )  2012.02  [Refereed]

     View Summary

    Electron beam nanoimprint lithography was proposed for fabricating the micro-/nanostructures of cross-linked poly(L-lactic acid) (RX-PLLA). PLLA with triallyl isocyanurate (TAIC) solutions were dropped on the Si-molds fabricated by the conventional EB lithography technique. PLLA/TAIC on Si-molds were imprinted and cross-linked with doses from 10 to 500 kGy at room temperature under vacuum. The micro-/nanostructures of RX-PLLA were successfully obtained with high accuracy. Hence, it was found that the imprinted structures of RX-PLLA (100 kGy irradiation) show low line edge roughness and high thermal durability at 120 degrees C. (C) 2012 The Japan Society of Applied Physics

    DOI

    Scopus

    4
    Citation
    (Scopus)
  • Improvement of the Durability of Crosslinked PTFE Molds for UV-/EB-Nanoimprint Lithography

    Tomohiro Takahashi, Akinobu Kobayashi, Satoshi Okubo, Tomoko Gowa Oyama, Takaharu Miura, Akihiro Oshima, Seiichi Tagawa, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   25 ( 2 ) 249 - 253  2012  [Refereed]

     View Summary

    It has been reported that the nano- /micro- fabricated crosslinked polytetrafluoroethylene (RX-PTFE) by focused ion beam (FIB) direct etching technique could be used as the polymeric molds for the ultraviolet nanoimprint lithography (UV-NIL) and electron beam NIL (EB-NIL). In this study, to evaluate the durability of RX-PTFE molds for repeating printing cycles, the RX-PTFE was spin-coated on two kinds of substrates; none-metal treated silicon wafer and 50 nm thick Al-layer deposited one. Then, RX-PTFE molds were obtained by FIB irradiation. 450 x 450 nm and 950 x 950 nm squares and phi 1000 nm circle were fabricated in 40 x 40 mu m areas. Intervals of the squares and circle were 450 nm, 950 nm and 1000 nm, respectively. In the case of none-treated substrate, the 3rd imprinted pattern was distorted. On the other hand, the 10th imprinted patterns with UV-NIL were successfully obtained with the Al-layer deposited substrate. Though it is concerned about the mechanical strength of RX-PTFE degrading due to EB irradiation, EB-NIL was similarly succeeded with Al-layer deposited substrate. It is considered that the mold durability for printing would be improved due to high adhesion between Al-layer and RX-PTFE, because the fluorination of Al was caused by crosslinking treatment at high temperatures. Thus, it is suggested that the durability of RX-PTFE mold with Al-layer deposited substrate would be retained after 10 times UV- /EB-NIL processes.

    DOI

    Scopus

  • Transparent Cross linked PTFE Mold Fabrication and Nano/Micro-Pattern Transfer to Photo-Curable Resin

    Akinobu Kobayashi, Tomoko Gowa Oyama, Akihiro Oshima, Seiichi Tagawa, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   25 ( 2 ) 217 - 221  2012  [Refereed]

     View Summary

    Nano-/micro-scale structures of transparent crosslinked polytetrafluoroethylene (RX-PTFE) mold have been fabricated by combined process which is thermal and radiation process for fabrication of RX-PTFE (TRaf process). The nano-/micro-fabricated RX-PTFE were attempted to be applied for the transparent polymer molds of UV nanoimprint lithography (NIL). The ability of the RX-PTFE mold for UV-NIL was evaluated by the imprinted patterns. The RX-PTFE molds and the imprinted structures obtained by UV-NIL were observed by a field emission scanning electron microscope (FE-SEM). As a result, imprinted structures of photo-curable resin (Trimethylolpropane-triacrylate: TMPTA) by UV-NIL using RX-PTFE mold were successfully obtained. The nano-scale L&S patterns, square (410 nm X 410 nm) and hole (phi 170 nm) array patterns were clearly obtained.

    DOI

    Scopus

  • Evaluation of resist sensitivity in extreme ultraviolet/soft x-ray region for next-generation lithography

    Tomoko Gowa Oyama, Akihiro Oshima, Masakazu Washio, Seiichi Tagawa

    AIP ADVANCES   1 ( 4 )  2011.12  [Refereed]

     View Summary

    At and below the 11 nm node, shortening the exposure wavelength to >10 nm (extreme ultraviolet (EUV)/soft x-ray region), especially at 6.6-6.8 nm, has been discussed as next-generation EUV lithography. In this study, dose/sensitivities of typical resists were obtained at several wavelengths down to 3.1 nm and were found to depend on the wavelength. However, it was confirmed that the absorbed dose, calculated from the dose/sensitivity and the respective linear absorption coefficient, was almost independent of the wavelength and constant for each resist. Thus, the resist sensitivity for next-generation lithography was predicted at wavelengths <10 nm. Copyright 2011 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. [doi:10.1063/1.3665672]

    DOI

    Scopus

    17
    Citation
    (Scopus)
  • Cs-Te photocathode RF electron gun for applied research at the Waseda University

    Kazuyuki Sakaue, Hitoshi Hayano, Shigeru Kashiwagi, Ryunosuke Kuroda, Akihiko Masuda, Tatsuya Suzuki, Toshikazu Takatomi, Nobuhiro Terunuma, Junji Urakawa, Masakazu Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   269 ( 24 ) 2928 - 2931  2011.12  [Refereed]

     View Summary

    A compact electron accelerator based on photo-cathode RF electron gun is under development for applied research at the Waseda University. Higher charge and higher energy are key issues for applications such as pulse radiolysis experiment and laser-Compton X-ray generation. The new RF-gun cavity with cesium telluride (Cs-Te) photo-cathode which has higher quantum efficiency (Q.E.) compared with metal cathodes has been installed. The evaluation of Q.E. of the photo-cathode has been performed and the value obtained is more than 5% at the preparation stage. For understanding the Cs-Te cathode properties and the higher Q.E. operation, fundamental studies by single bunch beam operation have been performed resulting in more than 6 nC bunch charge with a high Q.E. of 2.9%. Additionally, the new RF-gun cavity was improved for obtaining a higher Q value. Higher beam energy, i.e. shunt impedance compared with old type cavity, was observed. The shunt impedance increased by about 20%. These successful results will considerably contribute to the applied research. (C) 2011 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • Development of function-graded proton exchange membrane for PEFC using heavy ion beam irradiation

    Fumiya Shiraki, Taeko Yoshikawa, Akihiro Oshima, Yuji Oshima, Yuya Takasawa, Naoyuki Fukutake, Tomoko Gowa Oyama, Tatsuya Urakawa, Hajime Fujita, Tomohiro Takahashi, Toshitaka Oka, Hisaaki Kudo, Takeshi Murakami, Yoshimasa Hama, Masakazu Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   269 ( 15 ) 1777 - 1781  2011.08  [Refereed]

     View Summary

    The graded energy deposition of heavy ion beam irradiation to polymeric materials was utilized to synthesize a novel proton exchange membrane (PEM) with the graded density of sulfonic acid groups toward the thickness direction. Stacked Poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) films were irradiated by Xe54+ ion beam with the energy of 6 MeV/u under a vacuum condition. The induced trapped radicals by the irradiation were measured by electron spin resonance (ESR) spectroscopy. Irradiated films were grafted with styrene monomer and then sulfonated. X-ray photo-electron spectroscopy (XPS) spectra showed that the densities of sulfonic acid groups were controlled for injection "Surface" and transmit "Back" sides of the fabricated PEM. The membrane electrode assembly (MEA) fabricated by the function-graded PEM showed improved fuel cell performance in terms of voltage stability. It was expected that the function-graded PEM could control the graded concentration of sulfonic acid groups in PEM. (C) 2011 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • Study on Positive-Negative Inversion of Chlorinated Resist Materials

    Tomoko Gowa Oyama, Akihiro Oshima, Hiroki Yamamoto, Seiichi Tagawa, Masakazu Washio

    APPLIED PHYSICS EXPRESS   4 ( 7 )  2011.07  [Refereed]

     View Summary

    The chlorinated resist materials ZEP520A and ZEP7000 (ZEON Co) are changed from positive-tone to negative-tone by high dose electron beam (EB) and ion beam irradiation. Here, the reaction mechanisms of the positive-negative inversion induced by EB were attempted to be clarified with ultraviolet-visible (UV-vis) spectroscopy and X-ray photoelectron spectroscopy. The results indicated that dissociative electron attachment would be induced in response to the irradiation dose. For high dose irradiation (> 5 mC cm(-2)), it was suggested that crosslinking would become Predominant because of the structural changes in the resists and the lower scission ratio due to the decrease of the chlorine. (C) 2011 The Japan Society of Applied Physics

    DOI

    Scopus

    18
    Citation
    (Scopus)
  • 放射線によるさまざまな現象について : 福島第一原子力発電所における事故に鑑みて

    鷲尾 方一

    化学と教育   59 ( 7 ) 332 - 336  2011.07

     View Summary

    今回の東日本大震災においては地震及び津波によって極めて甚大な被害が報告されている。特に福島第一原子力発電所において,日本国内では初めての動力炉での過酷事故が引き起こされた。この原因究明等については時間を待つ必要があるが,現在分っている範囲で事故の経緯と放射線の問題について解説を行う。特に放射線による健康被害等については風評被害も報告されるなど,冷静さを逸脱した多くの報道がなされている。ここでは放射線応用の専門家の立場で,放射線の真実とも言うべきさまざまな現象について説明しておきたい。

    DOI CiNii

  • Experimental results of an rf gun and the generation of a multibunch beam

    Abhay Deshpande, Sakae Araki, Masafumi Fukuda, Kazuyuki Sakaue, Nobuhiro Terunuma, Junji Urakawa, Masakazu Washio

    PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS   14 ( 6 )  2011.06  [Refereed]

     View Summary

    At the laser undulator compact x-ray source at KEK, our group has designed and built a new rf gun with a larger mode separation of 8.6 MHz and higher Q value than earlier guns. This paper presents details on the design and fabrication, low-power measurements, and tuning procedures followed in the fabrication of the gun cavity. We also give a detailed account of experiments performed with this gun and present measurement results. We have successfully generated 100 bunches per train with a 50 nC charge at 41 MeV and 300 bunches per train with a 160 nC charge at 5 MeV, with low peak-to-peak energy difference. In the future, we plan to go up to a 0.5 nC charge per bunch in an 8000-bunch train at low energy and a 2 nC charge per bunch in a 100-bunch train at high energy. This will make it possible to have higher charge available for laser-beam collisions, thus enabling the generation of high flux soft x rays using the low-energy electron beam and approximately 30 keV x rays using the high-energy electron beam.

    DOI

    Scopus

    20
    Citation
    (Scopus)
  • Development of a laser pulse storage technique in an optical super-cavity for a compact X-ray source based on laser-Compton scattering

    Kazuyuki Sakaue, Sakae Araki, Masafumi Fukuda, Yasuo Higashi, Yosuke Honda, Noboru Sasao, Hirotaka Shimizu, Takashi Taniguchi, Junji Urakawa, Masakazu Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   637   S107 - S111  2011.05  [Refereed]

     View Summary

    With the ongoing progress of pulse laser storage technology, a compact X-ray source based on laser-Compton scattering, with sufficient photon flux for practical use, is soon to be realized. The super-cavity is one of the most feasible sources for the production of both high-average-power and high-peak-power laser pulses. Our group has been developing a continuous pulse storage and quasi-continuous interaction scheme with a multi-bunch electron linac. We have demonstrated a burst storage technique that enhances the laser pulse energy synchronized with the electron bunch train by using a quasi-continuous-wave laser amplifier. This laser pulse storage technique has achieved an average power of 2.45 kW and a pulse energy of 112 RI at the interaction timing in a super-cavity. In this paper, we describe the principle and recent progress of laser pulse storage in an optical super-cavity. (C) 2010 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    19
    Citation
    (Scopus)
  • S-band linac-based X-ray source with pi/2-mode electron linac

    Abhay Deshpande, Sakae Araki, Tanuja Dixit, Masafumi Fukuda, R. Krishnan, Sanjay Pethe, Kazuyuki Sakaue, Nobuhiro Terunuma, Junji Urakawa, Masakazu Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   637   S62 - S66  2011.05  [Refereed]

     View Summary

    The activities with the compact X-ray source are attracting more attention, particularly for the applications of the source in medical fields. We propose the fabrication of a compact X-ray source using the SAMEER electron linear accelerator and the KEK laser undulator X-ray source (LUCX) technologies. The linac developed at SAMEER is a standing wave side-coupled S-band linac operating in the pi/2 mode. In the proposed system, a photocathode RF gun will inject bunches of electrons in the linac to accelerate and achieve a high-energy, low-emittance beam. This beam will then interact with the laser in the laser cavity to produce X-rays of a type well suited for various applications. The side-coupled structure will make the system more compact, and the pi/2 mode of operation will enable a high repetition rate operation, which will help to increase the X-ray yield. (C) 2010 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    4
    Citation
    (Scopus)
  • Progress of high average power, short-pulse laser technology for the Compton X-ray source

    Akira Endo, Kazuyuki Sakaue, Masakazu Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   637   S33 - S36  2011.05  [Refereed]

     View Summary

    Recent progress is reported in the development of high average power, short-pulse laser technology, which is relevant toward achieving a high X-ray flux in a Compton X-ray source for use in various applications. The Yb-based laser material is suitable for high-pulse energy in a picosecond pulse length. The thin disc amplifier technology is now close to operating continuously with 1 J, 2 ps, at a 100 Hz repetition rate with a multi-pass amplification scheme. The average power is 100 W at a 1030 nm wavelength. The laser beam quality is fine enough to focus on the bunched electron beam from a photocathode/S-band linac single-pass accelerator and to generate an X-ray flux of 10(9) photons/s at 100 Hz. The short-pulse carbon dioxide (CO2) laser has an advantage for a Compton X-ray source in high X-ray flux applications. The short-pulse amplification of the CO2 laser pulse has been demonstrated, at a power level of more than 10 kW at a 100 kHz repetition rate in a single laser beam, for application in the plasma generation for an extreme ultraviolet light source, using a commercially available RF-pumped laser module. The pulse length is now limited to around 1 ns because of the bandwidth of the low-pressure gain medium. The additional pulse compression scheme makes a high average power, pulsed CO2 laser ideal for various applications of the Compton X-ray source. (C) 2010 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Study on depth profile of heavy ion irradiation effects in poly(tetrafluoroethylene-co-ethylene)

    Tomoko Gowa, Tomoyuki Shiotsu, Tatsuya Urakawa, Toshitaka Oka, Takeshi Murakami, Akihiro Oshima, Yoshimasa Hama, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   80 ( 2 ) 264 - 267  2011.02  [Refereed]

     View Summary

    High linear energy transfer (LET) heavy ion beams were used to irradiate poly(tetrafluoroethylene-co-ethylene) (ETFE) under vacuum and in air. The irradiation effects in ETFE as a function of the depth were precisely evaluated by analyzing each of the films of the irradiated samples, which were made of stacked ETFE films. It was indicated that conjugated double bonds were generated by heavy ion beam irradiation, and their amounts showed the Bragg-curve-like distributions. Also, it was suggested that higher LET beams would induce radical formation in high density and longer conjugated C=C double bonds could be generated by the second-order reactions. Moreover, for samples irradiated in air, C=O was produced correlating to the yield of oxygen molecules diffusing from the sample surface. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    8
    Citation
    (Scopus)
  • Change in surface morphology of polytetrafluoroethylene by reactive ion etching

    Tomohiro Takahashi, Yuki Hirano, Yuya Takasawa, Tomoko Gowa, Naoyuki Fukutake, Akihiro Oshima, Seiichi Tagawa, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   80 ( 2 ) 253 - 256  2011.02  [Refereed]

     View Summary

    Polytetrafluoroethylene (PTFE) was exposed to Ar, CF4, N-2 and O-2 plasmas using a reactive ion etching facility. After the exposure, the change in the surface morphology of PTFE was examined and characterization studies were performed for the etching rate, surface roughness, radical yields, chemical structures, water repellency and so on. The etching rates of Ar, CF4, N-2 and O-2 plasmas were 0.58, 7.2, 4.4 and 17 mu m/h, respectively. It was observed that needle-like nano-fiber structures on the surface were irregularly fabricated by the CF4 plasma. In addition, when the water repellency of exposed samples was evaluated by contact angle, they showed super-hydrophobic properties: contact angle over 150 degrees. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    20
    Citation
    (Scopus)
  • Study on resist sensitivities for nano-scale imaging using water window X-ray microscopy

    Tomoko Gowa, Tomohiro Takahashi, Akihiro Oshima, Seiichi Tagawa, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   80 ( 2 ) 248 - 252  2011.02  [Refereed]

     View Summary

    The sensitivities of deep-UV resist TDUR-P722 (Tokyo Ohka Kogyo Co., Ltd.) and two types of electron beam (EB) resists ZEP520A and ZEP7000 (ZEON Co.) to soft X-rays in the water window region (284-532 eV) were investigated for the nano-scale imaging of the contact X-ray microscopy. At the periphery of the water window, there are absorption edges of main constituent elements of the resist materials, namely carbon and oxygen. It was found that the sensitivities varied widely along the range of X-ray energies used, which correlated with the X-ray absorption of the resists. Moreover for the first time, it was confirmed that K- and L-edge absorptions have a strong influence on the resist sensitivity. Among these resists, ZEP7000 had the highest sensitivity. It was suggested that water window X-ray imaging with nano-scale resolution would be possible with about 1/500 of the fluence, which has the same units (mJ/cm(2) or J/cm(2)) as that of so-called dose/sensitivity in the field of resist research, compared with the previously reported method of using polymethylmethacrylate (PMMA). The details of the reaction mechanisms of the resists will be published elsewhere. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    6
    Citation
    (Scopus)
  • Nano- and micro-fabrication of perfluorinated polymers using quantum beam technology

    Nozomi Miyoshi, Akihiro Oshima, Tatsuya Urakawa, Naoyuki Fukutake, Hiroyuki Nagai, Tomoko Gowa, Yuya Takasawa, Tomohiro Takahashi, Yukari Numata, Takanori Katoh, Etsuko Katoh, Seiichi Tagawa, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   80 ( 2 ) 230 - 235  2011.02  [Refereed]

     View Summary

    Micro- and nano-fabrication researches of various perfluorinated polymers carried out recently both by synchrotron radiation (SR) direct photo-etching and by focused ion beam (FIB) direct mask less etching are reviewed. After the irradiation, the etching depth of the fabricated samples has been evaluated by optical microscope and scanning electron microscope. SR-induced surface modifications were studied by solid-state F-19 nuclear magnetic resonance (NMR) spectroscopy and differential scanning calorimeter (DSC) analysis. It was found that the etching rate of FEP at 140 degrees C was highest and that of PTFE and PFA at 140 degrees C was lower in the SR etching. It was found that crosslinking reactions were induced by SR irradiation at the region within about 50 mu m from the irradiated surface. FIB mask less etching showed very attractive features for nano-scale fabrications. The aspect ratio for crosslinked PTFE (RX-PTFE) reached 390. In addition, the nano-scale controlled structures with high aspect and quality of RX-PTFE were obtained without solid debris. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    12
    Citation
    (Scopus)
  • Surface modification of polymeric materials using ultra low energy electron beam irradiation

    Akihiro Oshima, Fumiya Shiraki, Hajime Fujita, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   80 ( 2 ) 196 - 200  2011.02  [Refereed]

     View Summary

    An ultra low energy electron beam (UL-EB) was used to irradiate various polymeric materials such as fluorinated polymers and a polyimide under an oxygen-free atmosphere. After the irradiation of the polyimide, the change in the thermal properties was measured by DSC and TGA. The surface modification of fluorinated polymers was demonstrated by use of styrene grafting by the preirradiation grafting method. By the use of UL-EB irradiation it was possible to facilitate styrene monomer grafting onto the surface of fluorinated polymers without losing their material characteristics. Moreover, in the case of the polyimide (Kapton (TM)), which has excellent radiation resistance, the glass transition temperature was improved by about 20 degrees C by irradiation up to 40 MGy within 1 h. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    12
    Citation
    (Scopus)
  • Fabrication of PEFC membrane based on perfluorinated polymer using quantum beam induced grafting technique

    Akihiro Oshima, Yukiko Sato, Fumiya Shiraki, Naohiro Mitani, Kazuki Fujii, Yuji Oshima, Hajime Fujita, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   80 ( 2 ) 164 - 168  2011.02  [Refereed]

     View Summary

    The performance of a polymer electrolyte fuel cell (PEFC) is affected by the interfacial property between the proton exchange membrane (PEM) and the electrodes. Thus, development of well-laminated membrane electrode assemblies (MEAs) has been carried out. The hybrid PEM, consisting of perfluorosulfonic acid (PFSA) ionomer and sulfonated polystyrene grafted tetrafluoroethylene-co-hexafluorpropylene (sulfonated PS-g-FEP) synthesized by the soft electron beam (soft-EB) induced grafting method, was fabricated by mixing sulfonated PS-g-FEP with PFSA ionomer, which is coated on the interface of the PEM and the electrodes. The obtained hybrid PEM was characterized in terms of water uptake, ion exchange capacity, polarization performance and electrochemical impedance. The ion exchange capacity (IEC) of the hybrid PEM was 1.0-1.2 meq/g. The polarization curve and electrochemical impedance of the hybrid PEM was analyzed. As a result, the ionic conductivity was 0.16 S/cm and is the highest in the tested PEMs. The maximum power density is about 1.0 W/cm(2) with low humidity (relative humidity RH: 16%), which is 1.5 times higher than that of commercially available Nafion (R) 112. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • Nanofabrication of Sulfonated Polystyrene-g-FEP with Silver Ion (Ag+) using Ion Beam Direct Etching and Reduction

    Hidehiro Tsubokura, Akihiro Oshima, Tomoko Gowa Oyama, Hiroki Yamamoto, Takeshi Murakami, Seiichi Tagawa, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   24 ( 5 ) 513 - 516  2011

     View Summary

    Functionalized poly(tetrafluoroethylene-co-hexafluoropropylene (FEP)) was fabricated by electron beam (EB) induced grafting technique and chemical sulfonation treatment. The functionalized FEP (s-FEP) films were immersed in the silver nitrate (AgNO3) solution under ambient condition, to exchange on ionic sites from proton ion-form to Ag+ ion-form, and then the Ag-formed s-FEP polymers were obtained. Ag-formed s-FEP was irradiated with 30 keV Ga+ focused ion beam (FIB) and 6 MeV/u dispersed Ne10+ ion beam (DIB). The irradiated areas were evaluated by a scanning electron microscopy (SEM) with an energy dispersive X-ray spectroscopy (EDX). In both cases of FIB and DIB irradiations, the nano-scale particles were appeared on the surface of irradiated areas. From the results of EDX analysis for the particles, the peaks which were assigned to silver atoms were clearly detected, and peak intensities were higher than un-irradiated one. It is suggested that the Ag+ ions would be reduced by ion beam irradiation and appeared as silver nano-scale particles with pure silver metal and its oxidative chemical compounds.

    DOI

    Scopus

  • Direct fabrication of photomobile polymer materials with an adhesive-free bilayer structure by electron-beam irradiation

    Yumiko Naka, Jun-ichi Mamiya, Atsushi Shishido, Masakazu Washio, Tomiki Ikeda

    JOURNAL OF MATERIALS CHEMISTRY   21 ( 6 ) 1681 - 1683  2011  [Refereed]

     View Summary

    Azobenzene liquid-crystalline (LC) polymers coated on a flexible polymer substrate were directly crosslinked by electron beams (EBs). We demonstrated that EB-crosslinked azobenzene LC polymers could successfully work as photomobile polymer materials with an adhesive-free bilayer structure.

    DOI

    Scopus

    34
    Citation
    (Scopus)
  • Micro- and Nano-Scale Fabrication of Fluorinated Polymers by Direct Etching Using Focused Ion Beam

    Naoyuki Fukutake, Nozomi Miyoshi, Yuya Takasawa, Tatsuya Urakawa, Tomoko Gowa, Kazumasa Okamoto, Akihiro Oshima, Seiichi Tagawa, Masakazu Washio

    JAPANESE JOURNAL OF APPLIED PHYSICS   49 ( 6 )  2010.06  [Refereed]

     View Summary

    Micro- and nano-scale fabrications of various fluorinated polymers were demonstrated by direct maskless etching using a focused ion beam (FIB). The etching rates of perfluorinated polymers, such as poly(tetrafluoroethylene) (PTFE), poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP), poly(tetrafluoroethylene-co-perfluoroalkoxyvinylether) (PFA), were about 500-1000 times higher than those of partially fluorinated polymers, such as poly(tetrafluoroethylene-co-ethylene) (ETFE) and poly(vinilydene-fluoride) (PVdF). Controlled high quality and high aspect-ratio nanostructures of spin-coated cross-linked PTFE were obtained without solid debris. The height and diameter of the fibers were about 1.5 mu m and 90 nm, respectively. Their aspect ratio was about 17. (C) 2010 The Japan Society of Applied Physics

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • Preparation of Crosslinked Liquid-Crystalline Polymers by Electron-Beam Irradiation and Their Photoinduced Bending Behavior

    Yumiko Naka, Jun-ichi Mamiya, Atsushi Shishido, Masakazu Washio, Tomiki Ikeda

    MOLECULAR CRYSTALS AND LIQUID CRYSTALS   529   71 - 79  2010  [Refereed]

     View Summary

    We proposed a new approach to fabricate bilayer films with a crosslinked azobenzene liquid-crystalline (LC) polymer. The polyethylene (PE) substrates were coated with linear azobenzene LC polymers, and then the azobenzene layers were crosslinked by irradiation with electron beams (EBs). In the EB-irradiated films with ordered azobenzene moieties, exposure to UV light caused trans-cis isomerization and the change in alignment of azobenzene moieties. Bending of the bilayer films could be induced toward an actinic light source when they were irradiated from the side of the azobenzene layer, while they bent away from the actinic light source upon UV irradiation from the side of the PE layer. In both cases, the bent films reverted to the initial flat state by turning off the light, which could be repeated at room temperature.

    DOI

    Scopus

    1
    Citation
    (Scopus)
  • Ion Beam Irradiation Effects on Resist Materials

    Tomoko Gowa, Tomohiro Takahashi, Toshitaka Oka, Takeshi Murakami, Akihiro Oshima, Seiichi Tagawa, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   23 ( 3 ) 399 - 404  2010  [Refereed]

     View Summary

    6 MeV/u ion beams such as Si(14+), Ar(18+), Kr(36+) and Xe(54+) and 30 kV Ga(+) focused ion beam (FIB) were irradiated to a chemically amplified deep-UV resist TDUR-P722 (Tokyo Ohka Kogyo) and electron beam (EB) resists ZEP520A and ZEP7000 (ZEON). Clear patterns were obtained on all resists for high energy ion beams, and it was confirmed that resist sensitivities were correlated with the energy deposition. In contrast, high flux FIB irradiation induced crosslinking reactions of resist polymers, and positive-negative inversion took place.

  • Micro-fabrication of Biodegradable Polymers using Focused Ion Beam

    Satoshi Okubo, Tomohiro Takahashi, Yuya Takasawa, Tomoko Gowa, Takashi Sasaki, Naotsugu Nagasawa, Masao Tamada, Akihiro Oshima, Seiichi Tagawa, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   23 ( 3 ) 393 - 397  2010

     View Summary

    Microfabrication of biodegradable polymers such as poly(butylene succinate-co-adipate) (PBSA) and poly(epsilon-caprolactone) (PCL) were demonstrated using focused ion beam (FIB) with maskless direct etching. As the result, the micro structures of PBSA and PCL were obtained. The etching depth of both PBSA and PCL were increased with increasing FIB fluence, and the etching rates were estimated to be about 1.3 x 10(-18) mu m/(ions cm(-2)) and 1.2 x 10(-18) mu m/(ions cm(-2)), respectively. Moreover, very thin films of PBSA and PCL were made by spin-coating method. The thicknesses of the spin-coated samples were about 200 nm, and the surface roughness was less than 10 nm (RMS). The fine structures such as micro-gear of PBSA and PCL were obtained without solid debris. The line width of the fabricated structure was about 250 nm.

    DOI

    Scopus

    5
    Citation
    (Scopus)
  • Study on Functionally Gradient Proton Exchange Membrane fabricated by EB Irradiation with Heterogeneous Energy Deposition

    Hajime Fujita, Fumiya Shiraki, Taeko Yoshikawa, Akihiro Oshima, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   23 ( 3 ) 387 - 392  2010  [Refereed]

     View Summary

    The revolutionary functionally gradient proton exchange membranes were fabricated by EB irradiation with heterogeneous energy deposition. These heterogeneous energy deposition profiles (Depth-Dose profiles) were simulated by Monte Carlo simulation code EGS5. In the process of EB-grafting method of styrene onto base fluorinated polymer, the energy depositions selected from the Depth-Dose profiles were used. The grafted membranes were sulfonated with chlorosulfonic acid in carbon tetrachloride. The DOGs in the direction of thickness showed that EB Depth-Dose profiles corresponded to the EB grafting reaction. The functionally gradient proton exchange membranes had a water uptake gradient in the direction of depth, and hence could be a promising solution to manage water behavior in Membrane Electrode Assembly (MEA) of Polymer Electrolyte Fuel Cell (PEFC).

    DOI

    Scopus

    6
    Citation
    (Scopus)
  • Study on UV/EB Nanoimprint Lithography Using Nano-/Micro-fabricated Crosslinked PTFE Mold

    Tomohiro Takahashi, Yuya Takasawa, Tomoko Gowa, Satoshi Okubo, Takashi Sasaki, Takaharu Miura, Akihiro Oshima, Seiichi Tagawa, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   23 ( 1 ) 69 - 74  2010  [Refereed]

     View Summary

    Nano-/ micro-scale structures of crosslinked polytetrafluoroethylene (RX-PTFE) have been directly fabricated by focused ion beam (FIB). In this study, the nano-/ micro-fabricated RX-PTFE were attempted to be applied for the polymeric molds of nanoimprint lithography (NIL). The ability of the RX-PTFE mold for electron beam NIL (EB-NIL) was evaluated by the imprinted patterns, and compared with ultraviolet NIL (UV-NIL) method. The RX-PTFE molds and the imprinted structures obtained by UV- / EB-NIL were observed by a field emission scanning electron microscope (FE-SEM) and a scanning electron microscope (SEM). The height of imprinted structures was 860 nm, and the thinnest line width achieved in the experiments showed 180 nm with EB-NIL process. The estimated aspect ratio was 4.8.

    DOI

    Scopus

    7
    Citation
    (Scopus)
  • Study on Synchrotron Radiation Induced Photo Etching of Perfluorinated Polymers by K-edge Absorption of F-atom

    Akihiro Oshima, Hiroyuki Nagai, Toshiyuki Hyuga, Nozomi Miyoshi, Tatsuya Urakawa, Katsuyoshi Murata, Takanori Katoh, Etshuko Katoh, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   23 ( 3 ) 381 - 386  2010  [Refereed]

     View Summary

    Micro-fabrications of various perfluorinated polymers were carried out by the synchrotron radiation (SR) direct photo etching, and the SR-induced surface modifications were studied by DSC and F-19 solid-state NMR spectroscopy. The etching depth measurements of perfluorinated polymers were carried out by optical microscope. Although ETFE could be hardly etched, it was confirmed that the microstructures of PFA and FEP could be fabricated by SR direct photo etching. It was found that the etching rate of FEP at 140 degrees C was highest and those of PTFE and PFA at 140 degrees C were lower. It was found that crosslinking reactions were induced by the SR-irradiation at the region within 50 mu m from the irradiated surface.

  • Recent Progress of a Soft X-ray Generation System Based on Inverse Compton Scattering at Waseda University

    Kazuyuki Sakaue, Tomoko Gowa, Hitoshi Hayano, Yoshio Kamiya, Shigeru Kashiwagi, Ryunosuke Kuroda, Akihiko Masuda, Ryo Moriyama, Junji Urakawa, Kiminori Ushida, Xijie Wang, Masakazu Washio

    Radiation Physics and Chemistry   77 ( 10-12 ) 1136 - 1141  2008.10  [Refereed]

     View Summary

    At Waseda University, we are developing a table-top size soft X-ray source based on inverse Compton scattering between a high quality electron beam and a high power laser. Using 1047 nm laser beam (Nd:YLF) and 4.6 MeV electron beam generated from a photo-cathode rf-gun, we had already succeeded in generating inverse Compton X-rays. The energies are within the "water window" region (250-500 eV) which can be applied to biological studies. For good signal to noise ratio (SIN) and a larger number of photons, we remodeled our collision chamber and laser amplifier system. SIN is defined by the X-ray photon signal over all other noises and backgrounds such as a bremsstrahlung X-rays from a lost electron beam and an electric noises caused by a radiation and rf power source. With these modifications, the X-ray photons detected by a micro channel plate (MCP) have increased 10-fold to reach 312 ph/pulse. Total generated photons were estimated to be 3.3 X 10(4). Further, we succeeded in generating stable soft X-rays for more than 12 h. Good SIN ratio, stable X-rays have made it possible to observe the beam-laser interaction very precisely. By using this technique, we have measured the electron beam size at the collision point as 251 pm (a,) x 56 pm, (ay). (c) 2008 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    32
    Citation
    (Scopus)
  • Chemical and Radiation Cross-Linking of Polytetrafluoroethylene by Containing Fluorinated Compound

    Akihiro Oshima, Masakazu Washio

    POLYMER DURABILITY AND RADIATION EFFECTS   978   204 - 217  2008  [Refereed]

     View Summary

    The thermo-chemical-induced crosslinking of polytetrafluoroethylene (PTFE) has been demonstrated by using fluorinated-compound without any other catalyst materials. The heat-treatment for PTFE containing the various amount of fluorinated-compound was carried out at 350 degrees C +/- 5 degrees C for 30 minutes. After treatment, the various measurements and analysis were performed. By the solid-state F-19-NMR spectroscopy, the new signal appeared at -188 ppm, which is assigned to the fluorine signal of &gt;CF- group (Y-type crosslinking site). The obtained materials showed good mechanical properties and lower crystallinity, which were confirmed by tensile and flexural tests, and DSC analysis, compared with PTFE. Hence, the obtained material is confirmed to be crosslinked through thermal chemical reaction with decomposion of fluorinated-compound. The chemical-radiation synergetic crosslinking of PTFE (SX-PTFE) was carried out. By F-19-NMR spectroscopy, several new peaks were appeared at -85 ppm, - 89 ppm, - 110 ppm, - 114 ppm and - 188 ppm, respectively. The peaks at - 83 ppm and - 89 ppm correspond to -CF3 were assigned to the fluorine signals of chain end group in amorphous and branching chain end group, respectively. The peaks at -110 ppm and - 114 ppm were assigned to the fluorine signals of Y-type crosslinking site and hexafluoropropylene, respectively. The signal at -188 ppm is assigned to the fluorine signal of &gt;CF- group. The peak intensity was higher than chemical-crosslinking and radiation-crosslinking. The mechanical properties of the SX-PTFE composite were much improved. The wettability of the obtained materials was the same as that of PTFE. That is, wettability of obtained materials hold the original property.

  • Synthesis and characterization of PEFC membranes based on fluorinated-polymer-alloy using pre-soft-EB grafting method

    Fumihiro Muto, Akihiro Oshima, Tomoyuki Kakigi, Naohiro Mitani, Akio Matsuura, Kazuki Fujii, Yukiko Sato, Jingye Li, Masakazu Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   265 ( 1 ) 162 - 167  2007.12  [Refereed]

     View Summary

    Polymer electrolyte fuel cell (PEFC) membranes based on thin film of crosslinked perfluorinated polymer-alloys (RX-FA) have been fabricated by soft electron beam (soft-EB) grafting with styrene monomers using soft-EB irradiation under nitrogen atmosphere at room temperature (RT). The characteristic properties of styrene-grafted materials (GRX-FA) and sulfonated materials (SRX-FA) have been measured by differential scanning calorimetry (DSC) and FT-IR spectroscopy, ionic conductivity and so on. The glass transition temperatures (dry state) of all obtained SRX-FA were about 105 +/- 1 degrees C, which are higher than Nation (R). The ion exchange capacities of SRX-FA have been achieved about 3.3 meq/g (dry). The ionic conductivity of obtained SRX-FA has showed about 0.17 S/cm at 60 degrees C with relative humidity (RH) of similar to 95%. The ionic conductivities of the obtained SRX-FA were higher than that of conventional perfluoro-sulfonic acid membranes (PFSA). Fabricated membrane electrode assemblies (MEAs) based on the obtained SRX-FA have shown encouraging performance in the PEFC, compared with the conventional PFSA. The power density of obtained MEAs based on the SRX-FA was about 330-340 mW/cm(2) under 500 mA/cm(2) at 60 degrees C operation. Moreover, the maximum power densities of obtained MEAs based on the SRX-FA shows about 630mW/cm(2) at 60 degrees C. On the other hand, the power density at 500 mA/cm(2) and maximum power density of MEA based on Nafion (R) 112 were about 320 and 590 mW/cm(2) at 60 degrees C. Thus, the power density of the obtained SRX-FA was higher than that of conventional PFSA. (C) 2007 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    11
    Citation
    (Scopus)
  • Study on chemical structures of poly (tetrafluoroethylene-co-perfluoroalkylvinylether) by soft-EB irradiation in solid and molten state

    Tomoyuki Kakigi, Akihiro Oshima, Nozomi Miyoshi, Katsuyoshi Murata, Kazuki Fujii, Naohiro Mitani, Tatsuya Urakawa, Yukiko Sato, Akio Matsuura, Jingye Li, Takaharu Miura, Etsuko Katoh, Masakazu Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   265 ( 1 ) 118 - 124  2007.12  [Refereed]

     View Summary

    Poly (tetrafluoroethylene-co-perfluoroalkylvinylether) (PFA) was irradiated by soft electron beam (soft-EB) under nitrogen gas atmosphere in solid-state and its molten state, respectively. The changes of thermal property and chemical structures of irradiated PFA in solid-state and molten state were studied by differential scanning calorimetric analysis (DSC) and solid-state F-19 magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. By DSC analysis, the melting temperature shifted to lower temperatures, and crystallinity decreased with increasing soft-EB dose. By solid-state 19F MAS NMR spectroscopy, the new signals was observed and the detected new signals in irradiated PFA at 315 degrees C and at 30 degrees C were due to the tertiary carbon group with branching site (Y-type crosslinking site), perfluoro-propylene site and chain end methylene groups, respectively.
    Moreover, the molar ratio of perfluoroalkylvinylether (FAVE) structure to -CF2- units decreased with increasing dose. (C) 2007 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    3
    Citation
    (Scopus)
  • Efficient propagation of polarization from laser photons to positrons through compton scattering and electron-positron pair creation

    T Omori, M Fukuda, T Hirose, Y Kurihara, R Kuroda, M Nomura, A Ohashi, T Okugi, K Sakaue, T Saito, J Urakawa, M Washio, Yamazaki, I

    PHYSICAL REVIEW LETTERS   96 ( 11 ) 1 - 4  2006.03  [Refereed]

     View Summary

    We have demonstrated for the first time the production of highly polarized short-pulse positrons with a finite energy spread in accordance with a new scheme that consists of two-quantum processes, such as inverse Compton scattering and electron-positron pair creation. Using a circularly polarized laser beam of 532 nm scattered off a high-quality, 1.28 GeV electron beam, we have obtained polarized positrons with an intensity of 2x10(4) e(+)/bunch. The magnitude of positron polarization has been determined to be 73 +/- 15(stat)+/- 19(syst)% by means of a newly designed positron polarimeter.

    DOI

    Scopus

    96
    Citation
    (Scopus)
  • レーザーフォトカソードRFガン

    鷲尾方一

    The Review of Laser Engineering   34 ( 2 ) 148 - 153  2006.02

  • Compact soft x-ray source using Thomson scattering

    S Kashiwagi, R Kuroda, T Oshima, F Nagasawa, T Kobuki, D Ueyama, Y Hama, M Washio, K Ushida, H Hayano, J Urakawa

    JOURNAL OF APPLIED PHYSICS   98 ( 12 ) 123302 1 - 6  2005.12  [Refereed]

     View Summary

    A compact soft x-ray source using Thomson scattering, enabled by the combination of a picosecond laser and an electron rf gun, was developed aiming at biological studies such as those using an x-ray microscope. The x-ray source included both a photoinjector system and a picosecond laser system with a tabletop size of 2x2 m(2). An infrared laser beam (lambda(0)=1047 nm) was obtained from an all-solid-state mode-locked Nd:YLF laser system and injected into the photocathode of an accelerator system. A 4.2 MeV electron beam was generated from a laser-driven photocathode rf gun system. The residual laser beam was amplified up to about 4.2 mJ/pulse using a flash-lamp-pumped laser amplifier. Upon collision of the electron beam with the amplified laser beam, 300 eV soft x rays were generated by Thomson backscattering. The stable interaction between the two beams was achieved using the same seed laser pulse for irradiating the photocathode and the scattering process with laser photons. (c) 2005 American Institute of Physics.

    DOI

    Scopus

    30
    Citation
    (Scopus)
  • Synthesis of per-fluorinated polymer-alloy based on PTFE by high temperature EB-irradiation

    A Oshima, F Mutou, T Hyuga, S Asano, S Ichizuri, JY Li, T Miura, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   236   172 - 178  2005.07  [Refereed]

     View Summary

    In this study, synthesis of per-fluorinated polymer-alloy based on polytetrafluoroethylene (PTFE) has been demonstrated by high temperature irradiation techniques. The per-fluorinated polymer-blend thin films originated from polymer dispersion (PTFE, PTFE/PFA polymer-blend: FA and PTFE/FEP polymer-blend: FE) have been fabricated by the wire-bar coating equipment. The obtained films (thickness: 5-15 mu m) were irradiated by EB at 335 degrees C +/- 5 degrees C in nitrogen gas atmosphere.
    Characterization of irradiated polymer-blends has been performed by F-19 solid-state NMR spectroscopy, thermal analysis and so on. By DSC analysis, the heat of crystallization (Delta H-c of both irradiated polymer-blends were decreased with increase in absorbed dose. Moreover, the melting and crystallization temperatures of both materials shift to lower temperatures, compared with crosslinked PTFE. The obtained materials showed the lower crystallinity. By 19F solid-state NMR spectroscopy, the new signals appeared at around - 160 ppm and at - 188 ppm. The signals are assigned to the fluorine signals of CF groups, which represent crosslinking sites with Y-type (&gt; CF-) and Y'-type (&gt; C=CF-) in the polymer-blend chains. Thus, it is confirmed that the polymer-alloys with good performance based on PTFE are synthesized through the radiation crosslinking reaction between PTFE and PFA or FEP molecules. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    16
    Citation
    (Scopus)
  • Proton exchange membranes prepared by grafting of styrene/divinylbenzene into crosslinked PTFE membranes

    JY Li, S Ichizuri, S Asano, F Mutou, S Ikeda, M Iida, T Miura, A Oshima, Y Tabata, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   236   333 - 337  2005.07  [Refereed]

     View Summary

    Thin PTFE membranes were prepared by coating the PTFE dispersion onto the aluminum films. Thus the thin crosslinked PTFE (RX-PTFE) membranes were obtained by means of electron beam irradiation above the melting temperature of PTFE under oxygen-free atmosphere. The RX-PTFE membranes were pre-irradiated and grafted by styrene with or without divinylbenzene (DVB) in liquid phase. The existence of DVB accelerated the initial grafting rate. The styrene grafted RX-PTFE membranes are white colored, on the other hand, the styrene/DVB grafted RX-PTFE membranes are colorless. The proton exchange membranes (PEMs) were obtained by sulfonating the grafted membranes using chlorosulfonic acid. The ion exchange capacity (IEC) values of the PEMs ranging from 1.5 to 2.8 meq/g were obtained. The PEMs made from the styrene/DVB grafted membranes showed higher chemical stability than those of the styrene grafted membranes under oxidative circumstance. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    21
    Citation
    (Scopus)
  • Fabrication of PEFC membrane based on PTFE/FEP polymer-alloy using radiation-grafting

    S Asano, F Mutou, S Ichizuri, JY Li, T Miura, A Oshima, Y Katsumura, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   236   437 - 442  2005.07  [Refereed]

     View Summary

    Polymer electrolyte fuel cells (PEFC) membranes based on very thin film of network polytetrafluoroethylene (PTFE)/tetrafluoroethylene-co-hexafluoropropylene (FEP) polymer-alloy (PTFE/FEP polymer-alloy: FE), have been fabricated by radiation-grafting with reactive styrene monomers using electron beam irradiation (EB) under nitrogen atmosphere at room temperature. The characteristic properties of obtained materials have been measured by ion exchange capacity (IEC), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and so on. The grafting yields showed the initial rapid increase, and then tended to saturate above 5-8 h. The grafting yields of all FE with various network densities have been achieved 80-100%. The styrene-grafted materials were sulfonated by chlorosulfonic acid. The IECs of sulfonated materials based on FE polymer-alloy have been achieved 3.0 meq/g. This suggests that IEC value is independent on network density and PTFE/FEP blend ratio. The IEC values of obtained materials are about three times higher than those of commercial perfluoro-sulfonic acid (PFSA) membranes.
    By small angle X-ray scattering (SAXS), it is found that the higher network densities would give the smaller cluster sizes in sulfonated materials. Thus, the higher amount of FEP will give the smaller cluster formation of sulfonated materials. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    26
    Citation
    (Scopus)
  • Surface analysis of the proton exchange membranes prepared by pre-irradiation induced grafting of styrene/divinylbenzene into crosslinked thin PTFE membranes

    JY Li, S Ichizuri, S Asano, F Mutou, S Ikeda, M Iida, T Miura, A Oshima, Y Tabata, M Washio

    APPLIED SURFACE SCIENCE   245 ( 1-4 ) 260 - 272  2005.05  [Refereed]

     View Summary

    The proton exchange membranes were obtained by pre-irradiation induced grafting of styrene with or without divinylbenzene (DVB) into thin crosslinked polytetrafluoroethylene (RX-PTFE) membranes with the thickness around 10 &mu; m and successive sulfonation. The surface chemical structure and morphology of the non-grafted, the grafted, and the grafted and sulfonated RX-PTFE membranes were studied by means of X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analysis. From the F/C atom ratio result, it was known that there are mainly polystyrene grafts on the surfaces of the styrene grafted RX-PTFE membranes, while there are mainly PTFE chains on the surfaces of the RX-PTFE membranes grafted by styrene together with DVB. "Wave" shape morphology on the surfaces of the grafted RX-PTFE membranes was observed. The F/C atom ratios on the surfaces of the grafted and sulfortated membranes are little lower than the corresponding grafted membranes before sulfonation. On the surface of the sulfonated membranes, the "wave" shape morphology was also observed. The distributions of the polystyrene grafts in the RX-PTFE membranes matrixes were strongly affected by the concentration of the crosslinking co-monomer, DVB, used in the graft polymerization, and the sulfonation will not change the distribution of the grafts obviously. &COPY; 2004 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    27
    Citation
    (Scopus)
  • Pre-irradiation induced grafting of styrene into crosslinked and non-crosslinked polytetrafluoroethylene films for polymer electrolyte fuel cell applications. II: Characterization of the styrene grafted films

    J Li, K Sato, S Ichizuri, S Asano, S Ikeda, M Iida, A Oshima, Y Tabata, M Washio

    EUROPEAN POLYMER JOURNAL   41 ( 3 ) 547 - 555  2005.03  [Refereed]

     View Summary

    Crosslinked and non-crosslinked polytetrafluoroethylene films (RX-PTFE and V-PTFE films, respectively) were irradiated by gamma-ray and then grafted with styrene in liquid phase. Microscope FT-IR spectroscopy, TGA, solid state (13)C CP/MAS and high resolution HS/MAS NMR spectroscopy, wide-angle X-ray diffraction (WAXD) study were used to get the structural information of the styrene grafted RX-PTFE and V-PTFE films. From microscope FT-IR spectra of the grafted RX-PTFE films, the "grafting front mechanism" was proved. TGA analysis showed that the grafted films have a small degradation step and two main degradation steps. In the 13C CP/MAS NMR spectra of the non-grafted films, there are no signal due to the absence of the hydrogen atom. While in the spectra of the grafted films, there are signals attributed to the polystyrene grafts. In the 13 C HS/MAS NMR spectra of the grafted films, the relative intensity of the peaks attributed to the polystyrene grafts increased while the relative intensity of the peak attributed to PTFE matrix decreased with the increase in the DOG. From WAXD patterns, the intensity of the crystalline peak decrease with the increase in the DOG. The grafted films were sulfonated by chlorosulfonic acid and the results of highest IEC value exceeded 3.0. Those results will be reported in the near future. (C) 2004 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    35
    Citation
    (Scopus)
  • Technical development of profile measurement for the soft X-ray via Compton backward scattering

    Saito T, Oshima A, Ueyama D, Hidume K, Minamiguchi S, Hama Y, Washio M, Kuroda R, Kashiwagi S, Urakawa J, Hayano H, IEEE

    2005 Ieee Particle Accelerator Conference (Pac), Vols 1-4   2005   1677 - 1679  2005  [Refereed]

    DOI

  • Fabrication of a poly-electrolyte membrane based on cross-linked PTFE thin film by EB irradiation grafting

    A Oshima, T Miura, S Asano, S Ichizuri, JY Li, S Ikeda, M Iida, C Matsuura, Y Tabata, Y Katsumura, M Washio

    RESEARCH ON CHEMICAL INTERMEDIATES   31 ( 7-8 ) 585 - 593  2005  [Refereed]

     View Summary

    Polymer electrolyte fuel cell (PEFC) membranes based on cross-linked polytetrafluoroethylene (RX-PTFE) very thin film have been fabricated by radiation grafting with reactive styrene monomers using electron beam irradiation under nitrogen atmosphere at room temperature. The characteristic properties of obtained materials have been measured by differential scanning calorimetry, thermogravimetric analysis, FT-IR spectroscopy, etc. The glass transition temperatures and thermal decomposition temperatures of grafted materials strongly depend on the yields of styrene grafting onto base materials. The higher yields of grafting give lower thermal stability. The ion-exchange capacity of sulfonated materials is 3.0 mEquiv/g. The other properties of obtained membranes, such as chemical structure and rates of hydrogen gas transmission, are discussed.

  • Bunch length monitor using two-frequency analysis for RF gun system

    R Kuroda, S Kashiwagi, K Sakaue, M Washio, H Hayano, J Urakawa

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   43 ( 11A ) 7747 - 7752  2004.11  [Refereed]

     View Summary

    An rms (root mean square) bunch length monitor for a laser-driven photocathode rf gun system based on a two-frequency analysis technique has been developed. Typically, the photoelectron beam generated from the rf gun system has an energy of 3-5 MeV and an rms bunch length smaller. than 20 ps down to 3-4 ps. This monitor is suitable for such electron beam measurement. The rms bunch length as a function of rf phase was experimentally measured using both the rms bunch length monitor and streak camera technique using a 50 MeV electron beam at the KEK accelerator test facility (KEK-ATF) injector section which has an rf gun system and a 3-m-long accelerator structure. A numerical simulation study was also performed using the PARMELA code. The availability of this monitor was clearly verified by comparing the results. Consequently, this monitor was installed in the rf gun system at Waseda University and the rms bunch length measurement for a 3.5 MeV electron beam was precisely performed using the monitor.

    DOI

    Scopus

    11
    Citation
    (Scopus)
  • Pre-irradiation induced grafting of styrene into crosslinked and non-crosslinked polytetrafluoroethylene films for polymer electrolyte fuel cell applications. I: Influence of styrene grafting conditions

    JY Li, K Sato, S Ichiduri, S Asano, S Ikeda, M Iida, A Oshima, Y Tabata, M Washio

    EUROPEAN POLYMER JOURNAL   40 ( 4 ) 775 - 783  2004.04  [Refereed]

     View Summary

    Crosslinked and non-crosslinked polytetrafluoroethylene (PTFE) films [RX-PTFE and V-PTFE films, respectively], were irradiated in air at room temperature using gamma-rays from a (60)Co source. The irradiated films were grafted with styrene in liquid phase. The grafting of styrene into PTFE films was proved by FT-IR spectroscopy. The influence of the reaction temperature and pre-irradiation doses on the resulted degree of grafting was discussed. The grafting speed and the degree of grafting were determined by the reaction temperature and pre-irradiation doses. The apparent activation eneraies were calculated as 39.7 kJ/mol for RX-PTFE films and 59.5 kJ/mol for V-PTFE films. The dependence index on absorbed doses at pre-irradiation for RX-PTFE films is 0.66, and for V-PTFE films it is 1.57. The geometric size changes of the grafted films were measured and discussed. Interestingly, the thickness of the grafted films was strongly influenced by the reaction temperature. The tensile strength and the elongation at break of the non-grafted and grafted RX-PTFE and V-PTFE films were measured. The grafted films then are sulfonated by chlorosulfonic acid for polymer electrolyte fuel cell (PEFC) applications and the highest IEC value gained is over 3. The analysis of the sulforiated films are now in progress. (C) 2003 Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    57
    Citation
    (Scopus)
  • Application of Electron Beams for the Treatment of VOC Streams

    Koichi Hirota, Hiroki Sakai, Masakazu Washio, Takuji Kojima

    Ind. Eng. Chem. Res.   43   1185 - 1191  2004.01

  • Extreme expansion of proximity gap by double exposures using enlarged pattern masks for line and space pattern formation in x-ray lithography (evolution of exposure method to symmetric illumination)

    E Toyota, M Washio, H Watanabe, H Sumitani

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B   21 ( 6 ) 2821 - 2825  2003.11  [Refereed]

     View Summary

    The extendibility of x-ray lithography is limited by the usable proximity gap. The gap is considered to be larger than 10 mum. Practically, a line and space (L/S) pattern of 70 nm linewidth and 140 nm pitch can be formed at a 10 Am gap using a 1:1 exposure mask (1X mask). If a double-pitch mask (2 X mask), whose LIS pitch is twice as large as desired what to be printed on the wafer, is used while applying double exposures, the gap can be expanded greatly. A simulation result showed that using a 2X mask, a gap of more than 1000 mum can be used to form a L/S pattern of 200 nm pitch. An exposure test at a gap of 160 mum using the 2X mask proved sufficient to form the L/S pattern of 200 nm pitch. The principle of symmetric illumination explains this result well. The principle is also applicable to two-dimensional pattern formation, for which we propose a concept of mask design, i.e., the symmetric-illumination mask (SIM). Multidot images formed by the SIMs can produce mega- or giga-unit patterns of less than 25 nm linewidth by applying continuous writing. (C) 2003 American Vacuum Society.

    DOI

    Scopus

  • Study on poly-electrolyte membrane of crosslinked PTFE by radiation-grafting

    K Sato, S Ikeda, M Iida, A Oshima, Y Tabata, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   208   424 - 428  2003.08  [Refereed]

     View Summary

    Polymer electrolyte fuel cell membrane based on crosslinked polytetrafluoroethylene (PTFE) [RX-PTFE] has been processed by radiation-grafting with reactive styrene monomers by gamma-rays under atmospheric circumstances, and the characteristic properties of the obtained membranes have been studied. The grafting yields of styrene monomer onto RX-PTFE, which have various crosslinking densities, were in the range of 5-100%. At the reaction period of 24 h, the grafting yields for RX-PTFE with low crosslinking density, which was reacted at 60 degreesC, achieved 94%. As a tendency, the lower grafting temperature gives higher grafting ratio of styrene onto RX-PTFE. Moreover, the yields of subsequent sulfonation for all samples were close to 100%. Mechanical properties were decreased with increasing grafting yields; especially the membrane with higher grafting yields was brittle. Ion exchange capacity of sulfonated RX-PTFE reached 1.1 meq/g while maintaining the mechanical properties. (C) 2003 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    66
    Citation
    (Scopus)
  • Radiation-induced phenomena in ethylene-co-tetrafluoroethylene polymer temperature and LET effects

    A Oshima, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   208   380 - 384  2003.08  [Refereed]

     View Summary

    Irradiation temperature and linear energy transfer (LET) dependency on radiation-induced reactions of ethylene-co-tetrafluoroethylene polymer (ETFE) were investigated precisely by using low and high LET beams, and in a wide range of irradiation temperatures from 77 to 573 K including its melting temperature, respectively.
    At various temperatures irradiation by low LET beam such as gamma-rays or electron beams, significant changes were observed in the photo-absorption spectra in the wavelength region between 200 and 500 nm. The general tendency is that the absorption band shifts to longer wavelengths with higher irradiation temperatures. The enhancement of the photo-absorption at 200-500 nm is due to the formation of conjugated double bonds in ETFE by irradiation.
    By high LET beam irradiation at room temperature such as ion beams, the photo-absorption spectra was different from those of low LET beams, i.e. the new absorption bands around 250-450 nm was appeared. It could be suggested that the high LET beams induced the production of intermediate species in a localized area such as track structure. As a result, reaction kinetics are different from low LET beams. (C) 2003 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • Surface modification of polytetrafluoroethylene by synchrotron radiation

    Y Sato, D Yamaguchi, T Katoh, S Ikeda, Y Aoki, A Oshima, Y Tabata, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   208   231 - 235  2003.08  [Refereed]

     View Summary

    Surface modification of polytetrafluoroethylene (PTFE) films by the irradiation using synchrotron radiation (SR) below the melting temperature was studied. The changes in chemical structures, surface compositions and thermal properties of the SR-irradiated PTFE were examined by solid-state F-19 NMR, X-ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC), respectively. In order to investigate the degree of modification as a function of depth from the irradiated surface, some PTFE thin films were stacked in layers under vacuum and then they were irradiated with SR. It was found that crosslinking reaction was induced by SR-irradiation in the solid-state within 50 mum from the exposed surface and chain scission was dominant at deeper layers. (C) 2003 Elsevier B,V. All rights reserved.

    DOI

    Scopus

    15
    Citation
    (Scopus)
  • Extendibility of proximity x-ray lithography to 25 nm and below

    E Toyota, M Washio

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B   20 ( 6 ) 2979 - 2983  2002.11  [Refereed]

     View Summary

    Extendibility of proximity x-ray lithography (PXL) relates to three technical issues. They are the minimum proximity gap usable for steppers, the maximum allowable gap by exposure methods, and overall blur effect. The minimum usable gap g(s) (mum) for steppers is presumed to be g(s)=W-1/2, where W (nm) is the design rule (half pitch). The maximum allowable gap, g is expressed as g = alphaW(2)/lambda, where lambda is the average wavelength and a is a coefficient, which depends on the exposure methods using 1X masks or 2X masks. In the article, we have verified the equation (g = alphaW(2)/lambda) by simulation for one- and two-dimensional patterns, and determined the a values for each exposure method. For the blur effect, we evaluated the sigma values using a simple model. As a result, we concluded that PXL can be used by 25 nm and most probably by 18 nm design rule by changing the exposure methods corresponding to the progress of the design rule generations. (C) 2002 American Vacuum Society.

    DOI

    Scopus

    13
    Citation
    (Scopus)
  • Image formation by dynamic exposure with multispot beam in X-ray nanolithography

    E Toyota, M Washio

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   41 ( 6B ) 4404 - 4409  2002.06  [Refereed]

     View Summary

    We propose here a new method in X-ray nanolithography. Using this method. two-dimensional patterns kith a linewidth of 25nm can be formed. A conventional proximity X-ray lithography system is applicable to the method with a practical gap of approximately 81 m. A 2X mask is used in the method instead of a 1X mask, changing the mask-wafer position (not gap) during exposure. The mask forms multispot images on the wafer: thus the traces of the relative change of the mask-wafer position during exposure ('dynamic exposure') produce a periodic pattern, The image formability and operational productivity for three kinds of 2X masks proposed for application to this method are described.

    DOI

  • Micromachining of crosslinked PTFE by direct photo-etching using synchrotron radiation

    D Yamaguchi, T Katoh, Y Sato, S Ikeda, M Hirose, Y Aoki, M Iida, A Oshima, Y Tabata, M Washio

    MACROMOLECULAR SYMPOSIA   181   201 - 211  2002.05

     View Summary

    Micromachining of crosslinked PTFE (polytetrafluoroethylene) using synchrotron radiation direct photo-etching method has been demonstrated. High aspect-ratio microfabrication was carried out. The etching rate of crosslinked PTFE was higher than that of non-crosslinked PTFE. Through the etching rate measurements of various samples, it was found that synchrotron radiation etching rate of crosslinked PTFE only depends on the degree of crosslinking, neither molecular weight nor crystallinity. The effect of molecular motion on etching process was discussed from temperature dependence data on etching rate. Further-more, the surface region of synchrotron radiation irradiated sample was investigated by Fourier transform infrared spectroscopy and the experimental result showed that the modification induced by synchrotron radiation proceeded before desorption.

  • The local transformation of the chemical structures induced in polymers by heavy ion-beam irradiation: the characterization of ions in the interaction with materials

    Y Hama, T Oka, K Inoue, M Kitoh, M Washio, H Kudoh, M Sugimoto, T Seguchi

    RESEARCH ON CHEMICAL INTERMEDIATES   27 ( 4-5 ) 469 - 473  2001  [Refereed]

     View Summary

    The local transformations of the chemical structure induced in low density polyethylene (LDPE) by irradiation with various ions of different characteristics are investigated by using micro-FT-IR system. On irradiation with heavier ions than H+, the remarkable LET effect is found in the transformation of the trans-vinylene and the end-vinyl groups. This can not be found on irradiation with H+ or gamma -rays. Moreover, it is suggested that in calculation of the stopping power it is important to consider not only the energy of the injected ion, but also the charge.

  • Precisely synchronized two mode-locked lasers with optical phase-locked loop

    H Nagaoka, T Miura, F Kannari, K Takasago, K Torizuka, M Washio

    ADVANCED SOLID-STATE LASERS, PROCEEDINGS   50   429 - 434  2001  [Refereed]

     View Summary

    Two mode-locked Ti:sapphire lasers were synchronized with different kinds of phase-locked loops. Conventional phase-locked loop (EPLL) systems employ an electrical device known as a double balanced mixer for phase comparison. However, a novel phase-locked loop in our system employs an optical up-converted signal (OPLL). When two lasers were synchronized with the EPLL, the up-converted signal of two lasers was measured and the relative timing jitter for 1 ms was estimated to be longer than 430 fs. When two lasers were synchronized with the OPLL, the cross-correlation of two lasers could be measured for the small relative timing jitter. The timing jitter of two lasers for 1.8 s was 28 fs. The holding time of the OPLL was 60 minutes.

  • Development of high-brightness laser synchrotron source at BNL ATF

    Pogorelsky IV, Ben-Zvi I, Hirose T, Kashiwagi S, Kusche K, Kumita T, Omori T, Yakimenko V, Yokoya K, Urakawa J, Washio M

    ADVANCED ACCELERATOR CONCEPTS   569   571 - 582  2001  [Refereed]

  • High quality electron beam science at Waseda University

    S Kashiwagi, Y Hama, S Hara, H Ishikawa, R Kuroda, T Kobuki, T Oshima, K Sato, M Washio, A Yada, J Urakawa, H Hayano

    INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS   14 ( 1-4 ) 157 - 162  2001  [Refereed]

     View Summary

    At Waseda University, we have started a new research project named "High-Tech Research Center Project" which is supported by the Ministry of Education, Culture, Sports, Science and Technology. In this project, a laser photo-cathode rf-gun with 1.6 acceleration cells has been installed for production of low emittance and short bunched electron beam. The high quality electron beam is very powerful tool for the study on radiation physics, radiation chemistry, material science etc. Development of pulsed X-ray generation by the inverse Compton scattering between high quality electron beam and laser pulse obtained from an all-solid-state Nd:YLF laser system will be started in 2001 fiscal year. The system will be applied to the pulse radiolysis experiments for the studies on radiation physics and chemistry. In this paper, we will describe the X-ray generation experiment at Waseda University.

  • High-quality beam generation using an RF gun and a 150 MeV microtron

    R Kuroda, M Washio, S Kashiwagi, T Kobuki, Ben-Zvi, I, XJ Wang, T Hori, F Sakai, A Tsunemi, J Urakawa, ST Hirose

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   455 ( 1 ) 222 - 227  2000.11  [Refereed]

     View Summary

    Low-emittance sub-picosecond electron pulses are expected to be used in a wide field, such as free electron laser, laser acceleration, femtosecond X-ray generation by Inverse Compton scattering, pulse radiolysis, etc. In order to produce the low-emittance sub-picosecond electron pulse, we are developing a compact Racetrack Microtron (RTM) with a new 5 MeV injection system adopting a laser photo cathode RF gun (Washio et al., Seventh China-Japan Bilateral Symposium on Radiation Chemistry, October 28, Cengdu, China, 1996). The operation of RTM has been kept under a steady state of beam loading for long pulse mode so far (Washio et al., J. Surf Sci. Sec. Jpn. 19 (2) (1998) 23). In earlier work (Washio et al., PAC99, March 31, New York, USA, 1999), we have succeeded in the numerical simulation for the case of single short pulse acceleration. Finally, the modified RTM was demonstrated as a useful accelerator for a picosecond electron pulse generation under a transient state of beam loading. In the simulation, a picosecond electron pulse was accelerated to 149.6 MeV in RTM for the injection of 5 MeV electron bunch with a pulse length of 10 ps (FWHM), a charge of 1 nC per pulse, and an emittance of 3 pi mm mrad. (C) 2000 Elsevier Science B.V. All rights reserved.

  • Observation of high-intensity X-rays in inverse Compton scattering experiment

    S Kashiwagi, M Washio, T Kobuki, R Kuroda, Ben-Zvi, I, Pogorelsky, I, K Kusche, J Skaritka, Yakimenko, V, XJ Wang, T Hirose, K Dobashi, T Muto, J Urakawa, T Omori, T Okugi, A Tsunemi, Y Liu, P He, D Cline, Z Segalov

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   455 ( 1 ) 36 - 40  2000.11  [Refereed]

     View Summary

    We report the first results of high-intensity X-ray generation using Inverse Laser Compton scattering, This experiment was carried out by a US-Japan collaboration at the Brookhaven National Laboratory (BNL) Accelerator Test Facility (ATF) in September 1999. The 3.5 ps X-ray pulse at 6.5 keV, containing 3 x 10(6) X-ray photons was generated by the interaction of 60 MeV, 0.5 nC electron bunches and CO2 laser pulses of 600 MW peak power. (C) 2000 Elsevier Science B.V. All rights reserved.

  • JLC偏極陽電子ビームの研究Ⅴ.BNLにおける高輝度X線発生

    日本物理学会(2000年春の分科会)   30pSJ-10  2000.03

  • JLC偏極陽電子ビームの研究Ⅳ.エアロジェルカウンターの開発

    日本物理学会(2000年春の分科会)   30pSJ-9  2000.03

  • JLC偏極陽電子ビームの研究Ⅲ.偏極測定装置

    日本物理学会(2000年春の分科会)   30pSJ-8  2000.03

  • JLC偏極陽電子ビームの研究Ⅱ.レーザーと光学系

    日本物理学会(2000年春の分科会)   30pSJ-7  2000.03

  • JLC偏極陽電子ビームの研究Ⅰ.ATFにおけるコンプトン散乱実験

    日本物理学会(2000年春の分科会)   30pSJ-6  2000.03

  • フォトカソードRF電子銃による高品質電子ビームの生成

    日本物理学会誌   Vol.55,No.3,pp.196-201  2000.03

  • Project outline of High Quality Beam Generation at Waseda University

    Abstract of TSRP 2000   pp.280-283  2000.01

  • 低エネルギー電子線照射の応用技術

    エレクトロニクス材料・技術シリーズ/シーエムシー    2000.01

  • 早稲田大学における高品質ビーム発生計画

    第42回放射線化学討論会   pp.207-208  1999.11

  • Photo-electron Beam's Longitudinal Phase Space Tomography Studies at the BNL-ATF

    LCLS Fast Instrumentation Miniworkshop    1999.10

  • ジッター低減した2台のモード同期レーザーにおける時間同期精度の評価

    第47回応用日本物理学関係連合講演会   28a-ZD-5  1999.10

  • 位相変調マスクのみによる増幅されたフェムト秒パルスの波形整形

    第47回応用日本物理学関係連合講演会   29a-ZD-6  1999.10

  • 重イオン照射高密度PEの経時構造変化

    第42回放射線化学討論会   pp.123-124  1999.10

  • Iso-octaneとTetrahydrofuranの混合溶媒系における量子ビート振幅の減少

    第42回放射線化学討論会   pp.203-204  1999.10

  • イオン照射ポリエチレンの局所反応—エネルギー付与と線量の評価—

    第42回放射線化学討論会   pp.41-42  1999.10

  • 電子線照射の産業応用の現状と展望

    日本原子力学会   1-(10)  1999.09

  • 逆コンプトン散乱による高輝度X線発生

    第24回リニアック技術研究会   pp.308-310  1999.07

  • 計算機シミュレーションによる高品質電子ビーム発生

    第24回リニアック技術研究会   pp.182-184  1999.07

  • Evaluation of femtosecond X-rays produced by Thomson scattering under linear and nonlinear interactions between a low-emittance electron beam and an intense polarized laser light

    J Yang, M Washio, A Endo, T Hori

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   428 ( 2-3 ) 556 - 569  1999.06  [Refereed]

     View Summary

    The mechanisms of Thomson scattering under linear and nonlinear interactions are discussed theoretically and used to evaluate characters of femtosecond (fs) X-rays produced by collision between a low-emittance electron beam and an intense polarized laser light. In the evaluation, we start from the differential cross section of the Thomson scattering under the linear interaction, and calculate the effects of the interaction angle and the laser light polarization on the production of the fs X-rays. The energy and emission angular distributions of the produced fs X-rays are calculated under linear and nonlinear interactions between the electron beam and polarized laser light. A 214 keV (5.8 x 10(-3) nm) X-ray beam with a pulse length of 228 fs and an intensity of 3 x 10(7) photons/pulse is numerically obtained by using the listed parameters of a 100 fs pulse laser and a low-emittance electron beam. The pulse length of the X-rays is expected to be in the duration of 100 fs by developing a 50 fs pulse laser (wavelength of 1 mu m) and focusing the beam size down to 20 mu m for both electron beam and laser light. (C) 1999 Elsevier Science B.V. All rights reserved.

  • RFガンによる超低エミッタンスビームの発生機構

    日本物理学会 第54回年会 要旨集   28pYH11  1999.03

  • A High-duty 1.6 Cell s-Band RF Gun Driven by A psec Nd:YAF Laser

    Proc. Pac '99   WEA57  1999.03

  • Ultra-bright X-ray Generation Using Inverse Compton Scattering of Picosecond CO2 Laser Pulses

    Proc. of Pac '99   WEP132  1999.03

  • Simulation of Racetrack*Microtron for Acceleration of Picosecond Electron Pulses

    Proc.of PAC ‘ 99   WEP18  1999.03

  • 高性能加速器の現状と将来展望

    第62回 ラドテック研究会 講演会要旨集   pp7-23  1999.02

  • Evaluation of femtosecond X-rays produced by Thomson scattering under linear and nonlinear interactions between a low-emittance electron beam and an intense polarized laser light

    J. Yang, M. Washio, A. Endo, T. Hori

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   428 ( 2 ) 556 - 569  1999

     View Summary

    The mechanisms of Thomson scattering under linear and nonlinear interactions are discussed theoretically and used to evaluate characters of femtosecond (fs) X-rays produced by collision between a low-emittance electron beam and an intense polarized laser light. In the evaluation, we start from the differential cross section of the Thomson scattering under the linear interaction, and calculate the effects of the interaction angle and the laser light polarization on the production of the fs X-rays. The energy and emission angular distributions of the produced fs X-rays are calculated under linear and nonlinear interactions between the electron beam and polarized laser light. A 214 keV (5.8 × 10-3 nm) X-ray beam with a pulse length of 228 fs and an intensity of 3 × 107 photons/pulse is numerically obtained by using the listed parameters of a 100 fs pulse laser and a low-emittance electron beam. The pulse length of the X-ray is expected to be in the duration of 100 fs by developing a 50 fs pulse laser (wavelength of 1 μm) and focusing the beam size down to 20 μm for both electron beam and laser light.

    DOI

    Scopus

    58
    Citation
    (Scopus)
  • 量子ビート観測とODESR法による混合溶媒系におけるイオン対再結合過程の研究

    第41回 放射線化学討論会 要旨集   pp145-146  1998.10

  • 放射線照射高分子固体における化学構造変化と微視的表面解析

    第41回 放射線化学討論会 要旨集   pp115-116  1998.10

  • 被照射高分子中に生成したラジカル種の線種依存性

    第41回 放射線化学討論会 要旨集   pp107-108  1998.10

  • イオン照射LDPEの構造変化の粒子依存性

    第41回 放射線化学討論会 要旨集   pp9-10  1998.10

  • パルスラジオリシス用のあたらしい電子源の可能性

    第41回 放射線化学討論会 要旨集 /日本放射線化学会   pp89-90  1998.10

  • 電子線による紙・高分子素材の表面加工%機能化

    第7回放射線利用技術セミナー 講演資料/放射線利用振興協会   pp31-44  1998.10

  • 放射線化学研究のための新しい線源技術

    日本放射線化学会誌   66,pp40-41  1998.09

  • 電子線加工技術 -その基礎、応用、展望—

    フォトポリマー講習会講演資料   ppⅨ.1-19  1998.08

  • Simulations of Ultra Short Single Bunch*Operation on 150 MeV Microtron

    Proc. of EPAC ’98   pp517-519  1998.06

  • Evaluation of Femtosecond X-rays Produced by Inverse Compton Scattering Under Linear and Nonlinear Interactions Between A Low Emittance Electron Beam and An*Intense Polarized*Light

    Proc. of EPAC ’98   pp1082-1084  1998.06

  • Evaluation of Femtosecond X-ray produced by Inverse Compton Scattering under Linear and nonlinear Interaction between a Low Emittance Electron Beamand an Intense Polarized Laser

    5th International Workshop on Femtosecond Technology   p108  1998.02

  • Development of RF Electron Gun System for X ray Generation by Inverse Compton Scattering

    5th International Workshop on Femtosecond Technology,   p107  1998.02

  • レーザーコンプトン散乱によるフェムト秒X線の発生

    Journal of The Surface Science Society of Japan   19;2,pp23-29  1998.02

  • Output beam characteristics of 150 MeV microtron

    T Hori, H Tsutsui, D Amano, M Washio, J Yang, K Tani

    PROCEEDINGS OF THE 1997 PARTICLE ACCELERATOR CONFERENCE, VOLS 1-3     1266 - 1268  1998  [Refereed]

     View Summary

    Sub-picosecond electron pulses are desirable for generating femtosecond X-ray pulses. By numerical simulation, it has become clear that racetrack microtron (RTM) has unique features to produce very short electron bunches by itself. In addition, it has proved experimentally that RTM has beneficial characteristics to accelerate only an excellent quality beam in both emittance and energy spread. The measured and calculated results of such distinctives are shown in this paper.

  • Positron Accumlator Ring for Linear Collider and R&amp;D Plan

    KEK Preprint   97;216A  1997.11

  • Development of High Duty Operation RF Photoinjector

    The 11th symposium on Accelerator Science. &amp; Technology   pp473-475  1997.10

  • SEARCH FOR A CORRELATION BETWEEN POSITRONIUM FORMATION AND FLUORESCENCE INHIBITION BY SOLUTES IN AQUEOUS-SOLUTIONS

    JC ABBE, G DUPLATRE, Y TABATA, Y ITO, S TAGAWA, M WASHIO

    JOURNAL DE CHIMIE PHYSIQUE ET DE PHYSICO-CHIMIE BIOLOGIQUE   85 ( 1 ) 29 - 30  1988.01  [Refereed]

  • PARALLEL STUDY BETWEEN POSITRONIUM YIELD AND EMISSION-SPECTRA IN PERFLUOROBENZENE AND CYCLOHEXANE MIXTURES - INFLUENCE OF EXCITED-STATES ON POSITRONIUM YIELD

    ZC ZHANG, Y ITO, M WASHIO, H KOBAYASHI, S TAGAWA, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   28 ( 1 ) 65 - 68  1986  [Refereed]

  • THE FORMATION OF SOLUTE EXCITED TRIPLET-STATES VIA GEMINATE ION RECOMBINATION IN CYCLOHEXANE SOLUTIONS OF BIPHENYL AND PYRENE ON SUB-NANOSECOND AND NANOSECOND TIMESCALES

    S TAGAWA, Y TABATA, H KOBAYASHI, M WASHIO

    RADIATION PHYSICS AND CHEMISTRY   19 ( 3 ) 193 - 196  1982  [Refereed]

▼display all

Misc

  • The mechanism of optical attenuation length in ultrafast laser induced structural changes

    澁谷達則, 坂上和之, 小川博嗣, 佐藤大輔, DINH Thanh-Hung, 石野雅彦, 田中真人, 鷲尾方一, 東口武史, 錦野将元, 小林洋平, 黒田隆之助

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   82nd  2021

    J-GLOBAL

  • Time-resolved measurement of processing phenomena induced ultrashort laser pulse in quartz glass by transmission pump-probe imaging equipment

    寺澤英知, 寺澤英知, 佐藤大輔, 佐藤大輔, 澁谷達則, 盛合靖章, 小川博嗣, 小川博嗣, 田中真人, 田中真人, 黒田隆之助, 黒田隆之助, 小林洋平, 小林洋平, 坂上和之, 坂上和之, 鷲尾方一

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   68th  2021

    J-GLOBAL

  • CURRENT STATUS OF A SELF-RESONATING OPTICAL CAVITY FOR LASER-COMPTON SCATTERING SOURCES

    大塚誠也, 小柴裕也, 鷲尾方一, ARYSHEV Alexander, 浦川順治, 大森恒彦, 照沼信浩, 福田将史, 本田洋介, 上杉祐貴, 菅原直人, 坂上和之, 高橋徹, 保坂勇志

    日本加速器学会年会(Web)   17th  2020

    J-GLOBAL

  • Time Resolved Pump-Probe Imaging of Ablation Phenomena in Quartz Glass by the visible femtosecond laser

    寺澤英知, 寺澤英知, 佐藤大輔, 澁谷達則, 盛合靖章, 小川博嗣, 田中真人, 黒田隆之助, 坂上和之, 坂上和之, 鷲尾方一

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   67th  2020

    J-GLOBAL

  • Formation of Nano Periodic Structure on polyetheretherketone by Irradiating Femtosecond Pulsed Laser

    牛窪大樹, 牛窪大樹, 澁谷達則, 佐藤大輔, 佐藤大輔, 盛合靖章, 小川博嗣, 小川博嗣, 田中真人, 田中真人, 黒田隆之助, 黒田隆之助, 坂上和之, 坂上和之, 鷲尾方一

    放射線化学討論会講演要旨集   63rd  2020

    J-GLOBAL

  • Pump-probe imaging of processing phenomena by ultrashort laser pulse in quartz glass

    寺澤英知, 寺澤英知, 佐藤大輔, 佐藤大輔, 澁谷達則, 盛合靖章, 小川博嗣, 小川博嗣, 田中真人, 田中真人, 黒田隆之助, 黒田隆之助, 坂上和之, 坂上和之, 鷲尾方一

    放射線化学討論会講演要旨集   63rd  2020

    J-GLOBAL

  • 第17回放射線プロセスシンポジウム―その目的と技術の発展―

    鷲尾方一

    放射線と産業   ( 146 ) 4‐7  2019.06

    J-GLOBAL

  • 【粒子ビームサイエンスの進歩と展望-HIMACの成果を中心に-】(3章)【放射線化学】放射線化学におけるHIMAC施設 重粒子照射による高分子材料の空間制御 機能性材料開発を中心に

    鷲尾 方一, 大島 明博, 長澤 尚胤, 村上 健

    Radioisotopes   68 ( 4 ) 259 - 265  2019.04

     View Summary

    本稿では、早稲田大学を中心としたグループでこれまで行ってきた高エネルギー重粒子線による高分子材料への照射効果とその応用に関して記述する。重粒子線照射による放射線化学反応の微小空間における局所性に関して研究を行ってきた。得られた知見を元に、微小空間での重粒子線のエネルギー付与量を制御し、空間的に制御された分布を持ったラジカルを誘起し、グラフト反応させることを通じ、空間制御型の機能性材料(PEFC:Polymer Electrolyte Fuel Cell)の創製を行ってきた。(著者抄録)

  • 紫外線のフェムト秒レーザーによる合成石英のアブレーション閾値のパルス幅依存性の研究

    寺澤英知, 寺澤英知, 佐藤大輔, 澁谷達則, 盛合靖章, 黒田隆之助, 坂上和之, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   74 ( 1 ) ROMBUNNO.15pG107‐7  2019.03

    J-GLOBAL

  • 電子ビームの傾き制御を用いたコヒーレントTHz放射の高度化に関する研究

    蓼沼優一, BRAMELD M, SHEN Y, 村上達希, 坂上和之, 坂上和之, 鷲尾方一, 黒田隆之助, 平義隆

    日本物理学会講演概要集(CD-ROM)   74 ( 1 ) ROMBUNNO.17aG107‐4  2019.03

    J-GLOBAL

  • 高周波電子銃用Cs‐Teフォトカソードの同時蒸着法に関する研究

    丹羽智朗, 宮松順也, 坂上和之, 鷲尾方一, 飯島北斗

    日本物理学会講演概要集(CD-ROM)   74 ( 1 ) ROMBUNNO.14aG107‐3  2019.03

    J-GLOBAL

  • パルスラジオリシスに向けたErファイバーレーザーを用いたスーパーコンティニウム光作製システムの開発

    内田朋哉, 花井周太郎, 坂上和之, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   74 ( 1 ) ROMBUNNO.15pG107‐6  2019.03

    J-GLOBAL

  • レーザーコンプトン散乱のクラブ衝突化

    小柴裕也, 太田昇吾, 森田遼介, 鷲尾方一, 坂上和之, 東口武史, 浦川順治

    日本物理学会講演概要集(CD-ROM)   74 ( 1 ) ROMBUNNO.17aG107‐5  2019.03

    J-GLOBAL

  • クラブ衝突レーザーコンプトン散乱のためのYb系レーザーシステム開発

    森田遼介, 小柴裕也, 太田昇吾, 坂上和之, 坂上和之, 鷲尾方一, 東口武史, 浦川順治

    日本物理学会講演概要集(CD-ROM)   74 ( 1 ) ROMBUNNO.17aG107‐6  2019.03

    J-GLOBAL

  • 位相空間回転によるリニアコライダーのための高ルミノシティ扁平ビームの直接生成

    田村遼平, 西村武, 栗木雅夫, POWER John, 早野仁司, JIN Xiuguang, 許斐太郎, 清宮裕史, 山本尚人, PIOT Philippe, 柏木茂, 坂上和幸, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   74 ( 1 ) ROMBUNNO.14aG107‐4  2019.03

    J-GLOBAL

  • 短波長フェムト秒レーザーによる合成石英のアブレーション閾値のパルス幅依存性

    寺澤英知, 寺澤英知, 佐藤大輔, 澁谷達則, 盛合靖章, 黒田隆之助, 田中真人, 坂上和之, 鷲尾方一

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   66th   ROMBUNNO.9a‐W631‐7  2019.02

    J-GLOBAL

  • 極端紫外線フェムト秒パルスによる誘電体のレーザー加工

    澁谷達則, 坂上和之, DINH Thanh‐Hung, 高橋孝, 高橋孝, 石野雅彦, 東口武史, 鷲尾方一, 田中真人, 小川博嗣, 錦野将元, 小林洋平, 黒田隆之助

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   66th   ROMBUNNO.9p‐W631‐3  2019.02

    J-GLOBAL

  • Development of soft x-ray laser irradiation beamline for ablation and damage study

    Masahiko Ishino, Thanh Hung Dinh, Noboru Hasegawa, Kazuyuki Sakaue, Takeshi Higashiguchi, Satoshi Ichimaru, Masatoshi Hatayama, Masakazu Washio, Masaharu Nishikino

    Proceedings of SPIE - The International Society for Optical Engineering   10905  2019.01

     View Summary

    © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. The interactions of short pulse lasers with matter are interesting subjects not only in applications such as surface fabrication but also in physical phenomena for study. Optical short pulse lasers have abilities to occur the ablation phenomena accompanying the creation of high temperature, high pressure, and excited states of electrons. The picosecond soft x-ray laser (SXRL) pulse also has ability to occur the ablation. The SXRL having the wavelength of 13.9 nm and duration of 7 ps is one of attractive x-ray source for ablation study, because the ablation threshold obtained with the focused SXRL pulse is much smaller than those obtained with other lasers having longer durations and/or longer wavelengths. The low ablation threshold of a material for the SXRL beam has a possibility of efficient nanometer scale surface machining by an ablation. The ablation study will lead to the physical research and the direct surface machining. In addition, the wavelength of the SXRL is very close to the wavelength of the extreme ultraviolet (EUV) lithography system (λ = 13.5 nm). In the presentation, we report on development of the soft x-ray laser irradiation system. The irradiation system has an intensity monitor based on the Mo/Si multilayer beam splitter. This intensity monitor provides the irradiation energy onto sample surface. The SXRL has an ability to confirm the ablation threshold and to examine the damage property of EUV optical elements, which have the same specifications of those in the EUV lithography. And more, it is possible to evaluate the doses for sensitivity of resists.

    DOI

  • Demonstration of a terahertz pure vector beam by tailoring geometric phase

    Toshitaka Wakayama, Takeshi Higashiguchi, Kazuyuki Sakaue, Masakazu Washio, Yukitoshi Otani

    Scientific Reports   8 ( 1 )  2018.12

     View Summary

    We demonstrate the creation of a vector beam by tailoring geometric phase of left- and right- circularly polarized beams. Such a vector beam with a uniform phase has not been demonstrated before because a vortex phase remains in the beam. We focus on vortex phase cancellation to generate vector beams in terahertz regions, and measure the geometric phase of the beam and its spatial distribution of polarization. We conduct proof-of-principle experiments for producing a vector beam with radial polarization and uniform phase at 0.36 THz. We determine the vortex phase of the vector beam to be below 4%, thus highlighting the extendibility and availability of the proposed concept to the super broadband spectral region from ultraviolet to terahertz. The extended range of our proposed techniques could lead to breakthroughs in the fields of microscopy, chiral nano-materials, and quantum information science.

    DOI PubMed

  • Deep-hole drilling of amorphous silica glass by extreme ultraviolet femtosecond pulses

    Tatsunori Shibuya, Takashi Takahashi, Kazuyuki Sakaue, Thanh Hung Dinh, Hiroyuki Hara, Takeshi Higashiguchi, Masahiko Ishino, Yuya Koshiba, Masaharu Nishikino, Hiroshi Ogawa, Masahito Tanaka, Masakazu Washio, Yohei Kobayashi, Ryunosuke Kuroda

    Applied Physics Letters   113  2018.10

     View Summary

    © 2018 Author(s). A free-electron laser (FEL) is a robust tool for studying the interaction of intense X-rays with matter. In this study, we investigate the damage threshold and morphology of fused silica irradiated by extreme ultraviolet femtosecond pulses of a FEL. The experimental results indicate the superiority of the FEL processing. The FEL-damage threshold of fused silica at a wavelength of 13.5 nm is 0.17 J/cm 2 , which is 20 times lower than that of a near infrared (NIR) femtosecond laser. The relationship between the crater depth and laser fluence reveals that the effective absorption length is α eff-1 = 58 nm. The damage threshold and the absorption length are the key values for smooth crater formation. In addition, the formation of rim structures and microcracks, which are usually the critical issues in NIR laser processing, cannot be found in the interaction region. The hole diameter is maintained below the beam size at the exit.

    DOI

  • DDS構築へ向けた電子線グラフト重合によるpH応答膜の作製

    三上翔平, 山本裕貴, 志村亮弥, 大島明博, 鷲尾方一

    放射線化学討論会講演要旨集   61st   167‐168  2018.09

    J-GLOBAL

  • 電子線グラフト重合法による温度応答性細胞培養膜の作製

    志村亮弥, 末松良隆, 山本裕貴, 三上翔平, 武岡真司, 大島明博, 鷲尾方一

    放射線化学討論会講演要旨集   61st   169‐170  2018.09

    J-GLOBAL

  • レーザーアブレーション閾値のフルエンス・パルス幅依存性精密測定

    高橋孝, 高橋孝, 谷峻太郎, 黒田隆之助, 坂上和之, 鷲尾方一, 小林洋平, 小林洋平

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   79th   ROMBUNNO.18p‐136‐1  2018.09

    J-GLOBAL

  • 幾何学的位相によるTHzベクトルビームの実証

    若山俊隆, 坂上和之, 鷲尾方一, 大谷幸利, 大谷幸利, 東口武史, 東口武史

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   79th   ROMBUNNO.18a‐231C‐6  2018.09

    J-GLOBAL

  • 重イオンビームによる機能高分子材料の創製―核種・LETを高度に応用したエネルギー付与特性による新材料創製―

    鷲尾方一, 坂上和之, 長澤尚胤, 岡壽崇, 村上健

    量子科学技術研究開発機構研究報告書(Web)   ( 8 ) 141‐142 (WEB ONLY)  2018.09

    J-GLOBAL

  • クラブ衝突レーザーコンプトン散乱のためのYb系レーザーシステム開発

    森田遼介, 小柴裕也, 太田昇吾, 坂上和之, 鷲尾方一, 東口武史, 浦川順治

    アイソトープ・放射線研究発表会要旨集   55th   40  2018.06

    J-GLOBAL

  • パルスラジオリシスによるポリαメチルスチレンの照射効果の研究

    内田朋哉, 鷲尾方一, 坂上和之, 齋藤悠太郎

    アイソトープ・放射線研究発表会要旨集   55th   30  2018.06

    J-GLOBAL

  • 電子線グラフト重合法による温度応答性細胞培養膜の作製

    志村亮弥, 山本裕貴, 三上翔平, 山原有未, 大島明博, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   55th   31  2018.06

    J-GLOBAL

  • 電子ビームの傾き制御を用いたコヒーレントTHz放射の高強度化に関する研究

    蓼沼優一, 柳沢稜, BRAMELD Mari, 坂上和之, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   55th   41  2018.06

    J-GLOBAL

  • 電子ビーム傾き制御によるコヒーレントテラヘルツ光生成と高強度化に向けたターゲット媒質特性評価

    BRAMELD M, 柳沢稜, 蓼沼優一, 鷲尾方一, 坂上和之, 黒田隆之助, 平義隆

    日本物理学会講演概要集(CD-ROM)   73 ( 1 ) ROMBUNNO.22pK606‐1  2018.03

    J-GLOBAL

  • クラブ衝突によるレーザーコンプトンX線の高強度化

    小柴裕也, 太田昇吾, 森田遼介, 坂上和之, 鷲尾方一, 東口武史, 浦川順治

    日本物理学会講演概要集(CD-ROM)   73 ( 1 ) ROMBUNNO.25aK606‐1  2018.03

    J-GLOBAL

  • エミッタンス交換によるリニアコライダーのための高アスペクト比電子ビームの直接生成

    栗木雅夫, 柏木茂, 早野仁司, 清宮裕史, 山本尚人, 坂上和之, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   73 ( 1 ) ROMBUNNO.25aK607‐1  2018.03

    J-GLOBAL

  • 光蓄積共振器の開発状況とその展望

    坂上和之, 小柴裕也, 鷲尾方一, 浦川順治, 照沼信浩, 東口武史

    日本物理学会講演概要集(CD-ROM)   73 ( 1 ) ROMBUNNO.25aK606‐3  2018.03

    J-GLOBAL

  • 高周波電子銃用Cs‐Teフォトカソードの高耐久化に関する研究

    宮松順也, 小野央也, 坂上和之, 鷲尾方一, 飯島北斗, ZEN H

    日本物理学会講演概要集(CD-ROM)   73 ( 1 ) ROMBUNNO.25aK607‐3  2018.03

    J-GLOBAL

  • KEK小型電子加速器におけるレーザーコンプトン散乱を用いたX線源の開発

    福田将史, 荒木栄, ARYSHEV Alexander, 浦川順治, 坂上和之, 照沼信浩, 本田洋介, 森川裕, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   73 ( 1 ) ROMBUNNO.25aK606‐2  2018.03

    J-GLOBAL

  • 材料加工応用に向けたコヒーレント軟X線レーザーによる表面アブレーション

    錦野将元, 石野雅彦, DINH T‐H, 長谷川登, FAENOV A, PIKUZ T, 市丸智, 木下博雄, 坂上和之, 東口武史, 犬伏雄一, 今亮, 大和田成起, 羽多野忠, 鷲尾方一, 末元徹, 河内哲哉

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   65th   ROMBUNNO.18p‐A404‐3  2018.03

    J-GLOBAL

  • レーザーアブレーション閾値のフルエンス・パルス幅依存性

    高橋孝, 高橋孝, 谷峻太郎, 黒田隆之助, 坂上和之, 鷲尾方一, 小林洋平, 小林洋平

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   65th   ROMBUNNO.19p‐A404‐13  2018.03

    J-GLOBAL

  • 自発共鳴型レーザーパルス蓄積共振器の開発

    上杉祐貴, 浦川順治, 大森恒彦, 小菅淳, 坂上和之, 高橋徹, 保坂勇志, 本田洋介, 鷲尾方一

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   65th   ROMBUNNO.19p‐B203‐12  2018.03

    J-GLOBAL

  • 放射線プロセスの特徴とこれからの展望

    鷲尾方一

    放射線プロセスシンポジウム講演要旨・ポスター発表要旨集   17th   35‐36  2018

    J-GLOBAL

  • DDS構築へ向けた電子線グラフト重合によるpH応答膜の作製

    三上翔平, 山本裕貴, 志村亮弥, 鷲尾方一, 大島明博

    放射線プロセスシンポジウム講演要旨・ポスター発表要旨集   17th   80  2018

    J-GLOBAL

  • 電子線グラフト重合法による温度応答性細胞培養膜の作製

    志村亮弥, 山本裕貴, 三上翔平, 鷲尾方一, 末松良隆, 武岡真司, 大島明博

    放射線プロセスシンポジウム講演要旨・ポスター発表要旨集   17th   76  2018

    J-GLOBAL

  • 電子線グラフト重合法による直接グルコース形燃料電池用電解質膜の評価

    山本裕貴, 三上翔平, 志村亮弥, 鷲尾方一, 大島明博

    放射線プロセスシンポジウム講演要旨・ポスター発表要旨集   17th   81  2018

    J-GLOBAL

  • 小型加速器を用いた高強度コヒーレントTHz光の生成及び応用に関する研究

    ブラメルド真理, 蓼沼優一, 沈奕い, 村上達希, 佐々木智則, 鷲尾方一, 坂上和之, 黒田隆之助, 平義隆

    放射線プロセスシンポジウム講演要旨・ポスター発表要旨集   17th   60  2018

    J-GLOBAL

  • KEK小型電子加速器におけるレーザーコンプトン散乱を利用したX線生成強度の改善

    福田将史, 荒木栄, ARYSHEV Alexander, 浦川順治, 坂上和之, 照沼信浩, 本田洋介, 森川祐, 鷲尾方一

    日本加速器学会年会(Web)   15th   ROMBUNNO.WEP023 (WEB ONLY)  2018

    J-GLOBAL

  • 電子ビームの傾き制御を用いたコヒーレントTHz放射の高度化に関する研究

    蓼沼優一, BRAMELD Mari, SHEN Yiwei, 村上達希, 坂上和之, 鷲尾方一

    日本加速器学会年会(Web)   15th   ROMBUNNO.THP128 (WEB ONLY)  2018

    J-GLOBAL

  • レーザーコンプトン散乱のクラブ衝突化

    小柴裕也, 太田昇吾, 森田遼介, 坂上和之, 鷲尾方一, 東口武史, 浦川順治

    日本加速器学会年会(Web)   15th   ROMBUNNO.WEP109 (WEB ONLY)  2018

    J-GLOBAL

  • クラブ衝突レーザーコンプトン散乱のためのYb系レーザーシステム開発

    森田遼介, 小柴裕也, 太田昇吾, 坂上和之, 鷲尾方一, 東口武史, 浦川順治

    日本加速器学会年会(Web)   15th   ROMBUNNO.THP109 (WEB ONLY)  2018

    J-GLOBAL

  • 電子線パルスラジオリシス法によるポリαメチルスチレンの照射効果の研究

    内田朋哉, 花井周太郎, 坂上和之, 鷲尾方一

    日本加速器学会年会(Web)   15th   ROMBUNNO.THP130 (WEB ONLY)  2018

    J-GLOBAL

  • レーザーフォトカソード高周波電子銃から生成される電子ビームの3次元分布計測

    坂上和之, 小柴裕也, 佐々木智則, 大塚誠也, 鷲尾方一, 高富俊和, 浦川順治

    日本加速器学会年会(Web)   15th   ROMBUNNO.WEP041 (WEB ONLY)  2018

    J-GLOBAL

  • 高強度極端紫外線パルスによる誘電体の非熱的レーザー加工

    澁谷達則, 高橋孝, 坂上和之, DINH Thanh‐hung, 原広行, 東口武史, 石野雅彦, 小柴裕也, 錦野将元, 小川博嗣, 田中真人, 鷲尾方一, 小林洋平, 黒田隆之助

    日本加速器学会年会(Web)   15th   ROMBUNNO.THOL05 (WEB ONLY)  2018

    J-GLOBAL

  • Enhancement of laser-Compton X-ray by Crab crossing

    Yuya Koshiba, Shogo Ota, Ryosuke Morita, Kazuyuki Sakaue, Masakazu Washio, Takeshi Higashiguchi, Junji Urakawa

    Optics InfoBase Conference Papers   2018  2018

     View Summary

    Crab crossing of electron beam and laser pulse enables head-on collision in laser- Compton scattering. We will report prospects of crab crossing laser-Compton scattering and a suitable laser system based on a thin-disk regenerative amplifier.

    DOI

  • 電子線グラフト重合法とゾルゲル法による有機無機ハイブリッド電解質膜の研究

    西留武宏, 川中一平, 山本裕貴, 田倉貴史, 大島明博, 鷲尾方一

    放射線化学討論会講演要旨集   60th   35‐36  2017.09

    J-GLOBAL

  • DMFC用有機/無機ハイブリッド電解質膜の開発

    川中一平, 西留武宏, 山本裕貴, 田倉貴史, 大島明博, 鷲尾方一

    放射線化学討論会講演要旨集   60th   33‐34  2017.09

    J-GLOBAL

  • RF‐Deflectorを用いた電子ビームの3次元分布計測

    佐々木智則, 中里佑介, 坂上和之, 鷲尾方一

    放射線化学討論会講演要旨集   60th   144‐145  2017.09

    J-GLOBAL

  • パルスラジオリシスを用いたポリαアリルオキシメチルアクリル酸メチルの放射線化学反応初期過程の研究

    齊藤悠太郎, 内田朋哉, 保坂勇志, 近藤孝文, 吉田陽一, 鷲尾方一

    放射線化学討論会講演要旨集   60th   148‐149  2017.09

    J-GLOBAL

  • 重イオンビームによる機能高分子材料の創製―核種・LETを高度に応用したエネルギー付与特性による新材料創製―

    鷲尾方一, 長澤尚胤, 岡壽崇, 保坂勇志, 村上健

    量子科学技術研究開発機構研究報告書(Web)   ( 6 ) 167‐168 (WEB ONLY)  2017.09

    J-GLOBAL

  • レーザー加工の学理解明に向けたパルス幅可変レーザーシステムの開発

    高橋孝, 高橋孝, 中村卓磨, 谷峻太郎, 黒田隆之助, 坂上和之, 鷲尾方一, 小林洋平, 小林洋平

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   78th   ROMBUNNO.8a‐A410‐6  2017.08

    J-GLOBAL

  • ラジアル偏光内の渦成分の低減

    若山俊隆, 東口武史, 東口武史, 坂上和之, 鷲尾方一, 大谷幸利, 大谷幸利

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   78th   ROMBUNNO.8a‐S44‐2  2017.08

    J-GLOBAL

  • フェムト秒極端紫外レーザー光による有機薄膜のアブレーションに関する研究

    坂上和之, 石野雅彦, 井谷俊郎, 犬伏雄一, 市丸智, 大和田成起, 小倉拓人, 木下博雄, 小柴裕也, 今亮, SANTILLAN Julius Joseph, 篠崎夏美, 高橋孝, 田村賢紀, HUNG Dinh Thanh, 錦野将元, 西留武宏, 羽多野忠, 原広行, 東口武史, 山内駿, 鷲尾方一

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   78th   ROMBUNNO.5a‐S44‐6  2017.08

    J-GLOBAL

  • フェムト秒極端紫外レーザー光照射によるEUV多層膜のアブレーション

    市丸智, 錦野将元, 石野雅彦, 木下博雄, 犬伏雄一, 東口武史, 鷲尾方一, 坂上和之, 大和田成起, 羽多野忠, 畑山雅俊, 大知渉之, HUNG Dinh Thanh, 今亮, 原広行, 山内駿, 小倉拓人, 篠崎夏美, 小柴裕也, 高橋孝, 西留武宏, 奥哲

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   78th   ROMBUNNO.5a‐S44‐7  2017.08

    J-GLOBAL

  • ベクトルビームの偏光分布のシングルショット決定

    若山俊隆, 東口武史, 東口武史, 坂上和之, 鷲尾方一, 大谷幸利, 大谷幸利

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   78th   ROMBUNNO.8a‐S44‐3  2017.08

    J-GLOBAL

  • 超短パルス軟X線レーザー照射によるアブレーション

    石野雅彦, HUNG Dinh Thanh, FAENOV Anatory, 犬伏雄一, 市丸智, 大和田成起, 河内哲哉, 木下博雄, 今亮, 坂上和之, 末元徹, PIKUZ Tatiana, 保智己, 錦野将元, 長谷川登, 羽多野忠, 東口武史, 鷲尾方一

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   78th   ROMBUNNO.5a‐S44‐8  2017.08

    J-GLOBAL

  • 渦成分を低減したラジアル偏光ビームの実証

    若山俊隆, 東口武史, 東口武史, 坂上和之, 鷲尾方一, 大谷幸利, 大谷幸利

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   78th   ROMBUNNO.8a‐S44‐4  2017.08

    J-GLOBAL

  • 放射線グラフト重合法による直接グルコース形燃料電池用に向けた電解質膜の作製と評価

    山本裕貴, 川中一平, 西留武宏, 漆畑諒, 三上翔平, 大島明博, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   54th   37  2017.06

    J-GLOBAL

  • DDS構築へ向けた電子線グラフト重合によるpH応答膜の作製

    三上翔平, 西留武宏, 横田龍輝, 川中一平, 山原有未, 山本裕貴, 大島明博, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   54th   35  2017.06

    J-GLOBAL

  • RF‐Deflectorを用いた電子ビームの3次元分布計測

    佐々木智則, 中里佑介, 坂上和之, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   54th   9  2017.06

    J-GLOBAL

  • RF電子銃を用いたコヒーレントテラヘルツ光の生成と評価

    BRAMELD Mari, 西田万里子, 鷲尾方一, 坂上和之, 黒田隆之, 平義隆

    アイソトープ・放射線研究発表会要旨集   54th   10  2017.06

    J-GLOBAL

  • パルスラジオリシスシステム高度化に向けたフェムト秒ファイバーレーザーの開発

    齊藤悠太郎, 保坂勇志, 坂上和之, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   54th   11  2017.06

    J-GLOBAL

  • レーザーコンプトン散乱におけるクラブ衝突実現に向けた衝突用レーザーの開発

    高橋孝, 小柴裕也, 五十嵐大裕, 太田昇吾, 坂上和之, 鷲尾方一, 浦川順治

    日本物理学会講演概要集(CD-ROM)   72 ( 1 ) ROMBUNNO.17aK42‐5  2017.03

    J-GLOBAL

  • レーザーコンプトン光源応用を目指した自発共鳴型光蓄積共振器の開発研究

    保坂勇志, 上杉祐貴, 浦川順治, 大森恒彦, 小菅淳, 坂上和之, 高橋徹, 本田洋介, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   72 ( 1 ) ROMBUNNO.19pK42‐12  2017.03

    J-GLOBAL

  • 時間領域分光法を用いたコヒーレントテラヘルツパルス計測法の開発

    柳沢稜, 筧田知慶, 坂上和之, 鷲尾方一, 菅晃一

    日本物理学会講演概要集(CD-ROM)   72 ( 1 ) ROMBUNNO.19pK42‐7  2017.03

    J-GLOBAL

  • 高周波電子銃用CsKSbフォトカソードの開発

    小野央也, 宮松順也, 坂上和之, 鷲尾方一, 飯島北斗

    日本物理学会講演概要集(CD-ROM)   72 ( 1 ) ROMBUNNO.17aK42‐9  2017.03

    J-GLOBAL

  • KEK小型電子加速器でのレーザーコンプトンX線源開発におけるマルチバンチ電子ビーム生成の最適化

    福田将史, 荒木栄, 浦川順治, 坂上和之, 住友洋介, 照沼信浩, 本田洋介, 森川裕, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   72 ( 1 ) ROMBUNNO.19pK42‐10  2017.03

    J-GLOBAL

  • レーザーコンプトン散乱X線源用パルスレーザー蓄積共振器の開発

    坂上和之, 荒木栄, 浦川順治, 照沼信浩, 福田将史, 本田洋介, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   72 ( 1 ) ROMBUNNO.19pK42‐13  2017.03

    J-GLOBAL

  • パルスラジオリシスシステム高度化のためのErファイバーレーザーの開発

    齊藤悠太郎, 添田雄史, 保坂勇志, 坂上和之, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   72 ( 1 ) ROMBUNNO.20aS‐PS‐38  2017.03

    J-GLOBAL

  • RF deflectorを用いたRF gunにおける電子ビームの傾き角及び3次元分布計測

    中里佑介, 佐々木智則, 小柴裕也, 坂上和之, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   72 ( 1 ) ROMBUNNO.19pK42‐11  2017.03

    J-GLOBAL

  • クラブ衝突によるレーザーコンプトン散乱のルミノシティ増大

    小柴裕也, 五十嵐大裕, 高橋孝, 太田昇吾, 坂上和之, 鷲尾方一, 浦川順治

    日本物理学会講演概要集(CD-ROM)   72 ( 1 ) ROMBUNNO.17aK42‐4  2017.03

    J-GLOBAL

  • 自立安定性を備えた光蓄積共振器の開発

    上杉祐貴, 保坂勇志, 浦川順治, 大森恒彦, 大森恒彦, 小菅淳, 坂上和之, 高橋徹, 本田洋介, 本田洋介, 鷲尾方一

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   64th   ROMBUNNO.15p‐312‐8  2017.03

    J-GLOBAL

  • 1 Radiation Chemistry-Interaction and Reaction in the Materials by Ionizing Radiation-

    鷲尾方一

    Radioisotopes (Web)   66 ( 10 ) 385‐393(J‐STAGE)  2017

    DOI J-GLOBAL

  • クラブ衝突によるレーザーコンプトン散乱のルミノシティ増大

    小柴裕也, 高橋孝, 太田昇吾, 鷲尾方一, 坂上和之, 東口武史, 浦川順治

    日本加速器学会年会(Web)   14th   ROMBUNNO.WEP119 (WEB ONLY)  2017

    J-GLOBAL

  • Ybファイバレーザーを用いたテラヘルツパルスの時間領域分光

    坂上和之, BRAMELD Mari, 柳沢稜, 蓼沼優一, 鷲尾方一, 東口武史, 平義隆, 黒田隆之助, 浦川順治

    日本加速器学会年会(Web)   14th   ROMBUNNO.TUP114 (WEB ONLY)  2017

    J-GLOBAL

  • 電子ビームの傾き角制御によるコヒーレントテラヘルツ光の生成と性質の評価

    BRAMELD Mari, 柳沢稜, 蓼沼優一, 鷲尾方一, 坂上和之, 黒田隆之助, 平義隆

    日本加速器学会年会(Web)   14th   ROMBUNNO.TUP129 (WEB ONLY)  2017

    J-GLOBAL

  • RF電子銃用高耐久フォトカソードの開発

    宮松順也, 小野央也, 坂上和之, 鷲尾方一, 飯島北斗, 全炳俊

    日本加速器学会年会(Web)   14th   ROMBUNNO.WEP107 (WEB ONLY)  2017

    J-GLOBAL

  • RF‐Deflectorを用いた電子ビームの3次元分布計測

    佐々木智則, 中里佑介, 坂上和之, 鷲尾方一

    日本加速器学会年会(Web)   14th   ROMBUNNO.TUP085 (WEB ONLY)  2017

    J-GLOBAL

  • クラブ衝突レーザーコンプトン散乱のためのレーザーシステム開発

    太田昇吾, 小柴裕也, 高橋孝, 鷲尾方一, 坂上和之, 東口武史, 浦川順治

    日本加速器学会年会(Web)   14th   ROMBUNNO.WEP118 (WEB ONLY)  2017

    J-GLOBAL

  • DMFC用有機/無機ハイブリッド電解質膜の開発

    川中一平, 漆畑諒, 西留武宏, 田倉貴史, 大島明博, 鷲尾方一

    電池討論会講演要旨集   57th   336  2016.11

    J-GLOBAL

  • PEFC用微細加工電解質膜の有機無機ハイブリッド化

    西留武宏, 田倉貴史, 漆畑諒, 川中一平, 村上健, 大島明博, 鷲尾方一

    電池討論会講演要旨集   57th   334  2016.11

    J-GLOBAL

  • 電子ビームを用いたPEFC用微細加工型電解質膜の作製

    漆畑諒, 川中一平, 西留武宏, 大島明博, 鷲尾方一

    電池討論会講演要旨集   57th   335  2016.11

    J-GLOBAL

  • Mode-locked pulse oscillation of a self-resonating enhancement optical cavity

    Yuji Hosaka, Yosuke Honda, Atsushi Kosuge, Tsunehiko Omori, Kazuyuki Sakaue, Tohru Takahashi, Yuuki Uesugi, Junji Urakawa, Masakazu Washio

    arXiv   1610.03141  2016.10

    Internal/External technical report, pre-print, etc.  

     View Summary

    A power enhancement optical cavity is a compelling means of realizing a<br />
    pulsed laser with a high peak power and a high repetition frequency, which is<br />
    not feasible by using a simple amplifier scheme. However, a precise feedback<br />
    system is necessary for maintaining the narrow resonance condition of the<br />
    optical cavity, and has become a major technical issue in developing such<br />
    cavities. We developed a new approach that does not require any active feedback<br />
    system, by placing the cavity in the outer loop of a laser amplifier. We report<br />
    on the first demonstration of a mode-locked pulse oscillation using the new<br />
    system.

  • 電子ビームを用いたPEFC用微細加工型電解質膜の作製

    漆畑諒, 川中一平, 西留武宏, 大島明博, 鷲尾方一

    放射線化学討論会講演要旨集   59th   27‐28  2016.09

    J-GLOBAL

  • 医療デバイス応用に向けた温度応答性膜の放射線滅菌適性評価

    山原有未, 日名田暢, 長澤尚胤, 田口光正, 大島明博, 鷲尾方一

    放射線化学討論会講演要旨集   59th   9‐10  2016.09

    J-GLOBAL

  • 陽電子消滅法を用いたフッ素系燃料電池膜の自由体積空孔評価

    岡壽崇, 岡壽崇, 大島明博, 小野寺花梨, 鷲尾方一, 木野康志, 関根勉, 関根勉

    放射線化学討論会講演要旨集   59th   95‐96  2016.09

    J-GLOBAL

  • パルスラジオリシス法を用いた高粘度溶液中のレジスト材料の放射線化学初期過程の研究

    齊藤悠太郎, 保坂勇志, 添田雄史, 近藤孝文, 吉田陽一, 鷲尾方一

    放射線化学討論会講演要旨集   59th   103‐104  2016.09

    J-GLOBAL

  • 重イオンビームのエネルギー付与特性を利用したナノ空間制御材料の創製

    鷲尾方一, 坂上和之, 長澤尚胤, 岡壽崇, 村上健

    NIRS-M (National Inst. of Radiological Sciences)   ( 289 ) 188‐189  2016.09

    J-GLOBAL

  • RF‐Deflectorを用いたRF‐Gunにおける電子ビームの傾き角計測

    中里佑介, 西山将大, 坂上和之, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   53rd   20  2016.06

    J-GLOBAL

  • DMFC用有機/無機ハイブリッド電解質膜の開発

    川中一平, 漆畑諒, 西留武宏, 田倉貴史, 大島明博, 大島明博, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   53rd   4  2016.06

    J-GLOBAL

  • 放射線グラフト重合法を利用した高分子アクチュエータの開発

    横田龍輝, 山原有未, 日名田暢, 大島明博, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   53rd   3  2016.06

    J-GLOBAL

  • 高周波電子銃用CsKSbフォトカソードの開発

    小野央也, 鷲尾方一, 坂上和之, 飯島北斗

    アイソトープ・放射線研究発表会要旨集   53rd   18  2016.06

    J-GLOBAL

  • 電子線グラフト重合法による燃料電池用電解質膜に向けたアクリル酸電解質膜の作製

    西留武宏, 漆畑諒, 川中一平, 田倉貴史, 大島明博, 大島明博, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   53rd   9  2016.06

    J-GLOBAL

  • Feedback-free optical cavity with self-resonating mechanism

    Y. Uesugi, Y. Hosaka, Y. Honda, A. Kosuge, K. Sakaue, T. Omori, T. Takahashi, J. Urakawa, M. Washio

    APL Photonics   1  2016.05

     View Summary

    © 2016 Author(s). We demonstrated the operation of a high finesse optical cavity without utilizing an active feedback system to stabilize the resonance. The effective finesse, which is a finesse including the overall system performance, of the cavity was measured to be 394 000 ± 10 000, and the laser power stored in the cavity was 2.52 ± 0.13 kW, which is approximately 187 000 times greater than the incident power to the cavity. The stored power was stabilized with a fluctuation of 1.7%, and we confirmed continuous cavity operation for more than two hours. This result has the potential to trigger an innovative evolution for applications that use optical resonant cavities such as compact photon sources with laser-Compton scattering or cavity enhanced absorption spectroscopy.

    DOI

  • レーザーコンプトン光源のための自発共鳴型光蓄積共振器の開発

    保坂勇志, 上杉祐貴, 浦川順治, 大森恒彦, 小菅淳, 坂上和之, 高橋徹, 本田洋介, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   71 ( 1 ) ROMBUNNO.22AAP‐4  2016.03

    J-GLOBAL

  • 収束電子ビームを用いた高強度レーザーのプロファイル測定

    五十嵐大裕, 高橋孝, 坂上和之, 遠藤彰, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   71 ( 1 ) ROMBUNNO.19AAQ‐8  2016.03

    J-GLOBAL

  • KEK小型電子加速器におけるレーザー蓄積装置を用いた小型X線源(LUCX)の開発(18)

    福田将史, 荒木栄, 浦川順治, 坂上和之, 照沼信浩, 本田洋介, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   71 ( 1 ) ROMBUNNO.22AAP‐3  2016.03

    J-GLOBAL

  • コヒーレントチェレンコフ放射を用いたテラヘルツイメージング

    西田万里子, 水柿将貴, 鷲尾方一, 坂上和之, 黒田隆之助, 平義隆

    日本物理学会講演概要集(CD-ROM)   71 ( 1 ) ROMBUNNO.22AAP‐7  2016.03

    J-GLOBAL

  • フェムト秒ファイバレーザを用いたパルスラジオリシスシステムの開発

    添田雄史, 齊藤悠太郎, 伊藤孔明, 保坂勇志, 坂上和之, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   71 ( 1 ) ROMBUNNO.19AAQ‐9  2016.03

    J-GLOBAL

  • EOサンプリング法を用いたテラヘルツパルス検出試験

    筧田知慶, 鈴木里佳, 柳沢稜, 坂上和之, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   71 ( 1 ) ROMBUNNO.22AAP‐8  2016.03

    J-GLOBAL

  • 早稲田大学におけるマルチアルカリフォトカソードのRF電子銃導入に向けた研究

    小野央也, 松崎脩理, 鷲尾方一, 坂上和之, 飯島北斗

    日本物理学会講演概要集(CD-ROM)   71 ( 1 ) ROMBUNNO.20PAF‐7  2016.03

    J-GLOBAL

  • Picosecond, kW thin disc laser technology for LPP and FEL EUV sources

    A. Endo, M. Smrz, O. Novak, H. Turcicova, J. Muzik, J. Huynh, T. Mocek, K. Sakaue, M. Washio

    Optics InfoBase Conference Papers    2016.03

     View Summary

    © OSA 2016. Picosecond, high average power laser is critical in the HVM EUV source technology. 100kHz, mJ, laser is realized by thin disc laser architecture for LPP, and &gt; MHz laser is discussed for 10kW level EUV FEL.

  • クラブ衝突によるレーザーコンプトン散乱X線の高強度化

    小柴裕也, 五十嵐大裕, 高橋孝, 太田昇吾, 鷲尾方一, 坂上和之, 浦川順治

    放射線プロセスシンポジウム講演要旨・ポスター発表要旨集   16th   52  2016

    J-GLOBAL

  • 放射線グラフト重合法を利用した高分子アクチュエータの開発

    横田龍輝, 山原有未, 日名田暢, 鷲尾方一, 大島明博

    放射線プロセスシンポジウム講演要旨・ポスター発表要旨集   16th   72  2016

    J-GLOBAL

  • 高周波電子銃用CsKSbフォトカソードの開発

    小野央也, 宮松順也, 鷲尾方一, 坂上和之, 飯島北斗

    日本加速器学会年会(Web)   13th   ROMBUNNO.MOP045 (WEB ONLY)  2016

    J-GLOBAL

  • 収束電子線を用いた断面プロファイル計測システムの開発

    高橋孝, 五十嵐大裕, 太田昇吾, 坂上和之, 遠藤彰, 鷲尾方一

    日本加速器学会年会(Web)   13th   ROMBUNNO.TUP125 (WEB ONLY)  2016

    J-GLOBAL

  • 電子線傾き制御によるコヒーレントテラヘルツ放射の生成

    坂上和之, 西田万里子, 鷲尾方一, 平義隆, 黒田隆之助, 浦川順治

    日本加速器学会年会(Web)   13th   ROMBUNNO.MOP084 (WEB ONLY)  2016

    J-GLOBAL

  • RF‐Deflectorを用いたRF‐Gunにおける電子ビームの傾き角計測

    中里佑介, 西山将大, 佐々木智則, 坂上和之, 鷲尾方一

    日本加速器学会年会(Web)   13th   ROMBUNNO.MOP083 (WEB ONLY)  2016

    J-GLOBAL

  • レーザーコンプトン光源のための自発共鳴型光共振器のモードロックパルス発振

    保坂勇志, 上杉祐貴, 本田洋介, 小菅淳, 大森恒彦, 浦川順治, 高橋徹, 坂上和之, 鷲尾方一

    日本加速器学会年会(Web)   13th   ROMBUNNO.MOP053 (WEB ONLY)  2016

    J-GLOBAL

  • 収束電子線を用いた断面プロファイル計測システムの開発

    高橋孝, 五十嵐大裕, 太田昇吾, 遠藤彰, 鷲尾方一, 坂上和之

    放射線プロセスシンポジウム講演要旨・ポスター発表要旨集   16th   74  2016

    J-GLOBAL

  • レーザーコンプトン散乱におけるルミノシティ増大のためのクラブ衝突

    小柴裕也, 五十嵐大裕, 高橋孝, 太田昇吾, 坂上和之, 鷲尾方一, 浦川順治

    日本加速器学会年会(Web)   13th   ROMBUNNO.MOP054 (WEB ONLY)  2016

    J-GLOBAL

  • KEK小型電子加速器におけるマルチバンチ電子ビーム生成の改善

    福田将史, 荒木栄, 浦川順治, 照沼信浩, 本田洋介, 坂上和之, 鷲尾方一

    日本加速器学会年会(Web)   13th   ROMBUNNO.TUP065 (WEB ONLY)  2016

    J-GLOBAL

  • パルスラジオリシスシステム高度化のためのファイバーレーザーの開発

    齊藤悠太郎, 添田雄史, 保坂勇志, 坂上和之, 鷲尾方一

    日本加速器学会年会(Web)   13th   ROMBUNNO.TUP124 (WEB ONLY)  2016

    J-GLOBAL

  • Development of an EO sampling method for thz pulse detection

    T. Toida, R. Yanagisawa, M. Washio, K. Sakaue

    IPAC 2016 - Proceedings of the 7th International Particle Accelerator Conference     155 - 157  2016.01

     View Summary

    Copyright © 2016 CC-BY-3.0 and by the respective authors. We have been studying an S-band Cs-Te photo-cathode rf gun at Waseda University. The high quality electron beam produced by the rf gun is used to generate a high-power coherent terahertz pulse via Cherenkov radiation. This terahertz pulse can be applied to imaging and material analysis. As a preliminary step towards material analysis, we conducted experiments on terahertz time domain spectroscopy by EO sampling method to reveal major parameters of the terahertz pulse such as the pulse form and the spectrum. EO sampling method has high frequency response and suitable for high peak power terahertz pulses. In terahertz time domain spectroscopy, the duration of the probe light needs to be much faster than that of the terahertz pulse. Therefore, we developed a mode locked Yb fiber laser based on nonlinear polarization rotation as a reliable and cost-effective ultra-fast probe light source. The laser generates 3.59 ps chirped pulses which are compressed to 209 fs with a grating pair. In this conference, we will report the performance of the Yb fiber laser and results of EO sampling experiments.

  • Generation of a coherent Cherenkov radiation by using electron bunch tilting

    K. Sakaue, M. Nishida, M. Washio, R. Kuroda, Y. Taira, J. Urakawa

    IPAC 2016 - Proceedings of the 7th International Particle Accelerator Conference     1870 - 1872  2016.01

     View Summary

    Copyright © 2016 CC-BY-3.0 and by the respective authors. We have been developing a compact accelerator based on a laser photocathode rf electron gun at Waseda University. Low emittance and short bunched electron beam can be generated from the gun. Also, the rf transverse deflecting cavity was developed for the bunch length measurement. We performed an experiment for generating a coherent Cherenkov radiation using bunch tilting. The rf transverse deflector can give a tilt for the electron bunch, and the tilt angle was set to the Cherenkov radiating angle which determined by the target refractive index. We successfully demonstrated a coherent Cherenkov radiation and the characterization of the radiation. The principle of coherent Cherenkov radiation generation, the experimental results and future prospective will be presented at the conference.

  • Development and upgrade plan of an X-ray source based on laser Compton scattering in Laser Undulator Compact X-ray Source(LUCX)

    M. Fukuda, S. Araki, Y. Honda, N. Terunuma, J. Urakawa, K. Sakaue, M. Washio, A. Momose, M. Olbinado, Y. Wu, M. Kageyama, M. Kuribayashi

    IPAC 2016 - Proceedings of the 7th International Particle Accelerator Conference     1867 - 1869  2016.01

     View Summary

    Copyright © 2016 CC-BY-3.0 and by the respective authors. We have been developing a compact X-ray source based on Laser Compton scattering(LCS) at Laser Undulator Compact X-ray source(LUCX) accelerator in KEK. Our aim is to take a phase contrast image with Talbot interferometer within a few minutes at present. Owing to this, we need the flux of X-ray is 1.7×107 photons/pulse with 10% bandwidth. In the accelerator, an electron beam with the energy of 18-24MeV is generated by an S-band normal conducting accelerator. An electron beam collided with a laser pulse stacked in a 4-mirror planar optical cavity and then 6-10 keV X-rays are generated by LCS. Recently, X-ray imaging experiments such as refraction contrast imaging and phase contrast imaging with Talbot interferometer has been conducted. The flux of 9keV X-rays was 3×106 photons/sec with total band. Further improvements to realize the design X-ray flux are continued.

  • Direct high power laser diagnostic technique on focused electron bunch

    D. Igarashi, T. Takahashi, A. Endo, M. Washio, K. Sakaue

    IPAC 2016 - Proceedings of the 7th International Particle Accelerator Conference     4073 - 4075  2016.01

     View Summary

    Copyright © 2016 CC-BY-3.0 and by the respective authors. In laser produced plasma (LPP) EUV source, high intensity pulse CO2 laser is essential for plasma generation. To achieve high conversion efficiency and stable EUV power, we would like to measure a laser profile in the interaction point. However, there is no way to measure directly the laser profile of such a high intensity laser at the focus point. Therefore, we have been developing the direct high power laser diagnostic technique based on laser Compton scattering (LCS). LCS signal by using focused electron beam shows 1D laser profile. 2D laser profile can be reconstructed by one-dimensional laser profiles from various angles using computer tomography (CT). This method is suitable for high intensity laser, but very small spot size of electron beam is required. To obtain small spot size, we used S-band Cs-Te photocathode RF-Gun and specially designed solenoid lens at Waseda University. We already succeeded in observing minimum beam size of about 20μm rms and this is adequate to scan the CO2 laser. In this conference, we will report the result of the laser Compton scattering with pulse CO2 laser, the preparatory experiment in measuring a metal wire cross section and the present progresses.

  • 重イオンビームのエネルギー付与特性を利用したナノ空間制御材料の創製

    鷲尾方一, 大島明博, 濱義昌, 坂上和之, 岡壽崇, 村上健

    NIRS-M (National Inst. of Radiological Sciences)   ( 285 ) 182‐183  2015.12

    J-GLOBAL

  • 電子ビームを用いた微細加工型PEFC用高分子電解質膜に関する研究

    漆畑諒, 田倉貴史, 吉田智輝, 大島明博, 鷲尾方一

    電池討論会講演要旨集   56th   173  2015.11

    J-GLOBAL

  • レーザーコンプトン光源のためのパルス型自発共鳴型光蓄積共振器の開発

    保坂勇志, 赤木智哉, 上杉祐貴, 浦川順治, 大森恒彦, 小菅淳, 坂上和之, 高橋徹, 本田洋介, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   70 ( 2 ) ROMBUNNO.28ASN-7  2015.09

    J-GLOBAL

  • レーザーコンプトン光源のための高フィネス自発共鳴型光蓄積共振器の開発

    上杉祐貴, 赤木智哉, 浦川順治, 大森恒彦, 小菅淳, 坂上和之, 高橋徹, 保坂勇志, 本田洋介, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   70 ( 2 ) ROMBUNNO.28ASN-6  2015.09

    J-GLOBAL

  • 高強度中赤外ラジアル偏光渦の発生

    若山俊隆, 及川大基, 笹沼淳史, 荒居剛己, 藤井雄介, DINH T.‐H, 東口武史, 東口武史, 坂上和之, 鷲尾方一, 三浦泰祐, 高橋昭彦, 中村大輔, 岡田龍雄, 米村元喜, 大谷幸利

    応用物理学会秋季学術講演会講演予稿集(CD-ROM)   76th   ROMBUNNO.13P-2E-3  2015.08

    J-GLOBAL

  • 高エネルギー重粒子線による高分子材料への照射効果とその応用

    鷲尾方一

    NIRS-M (National Inst. of Radiological Sciences)   ( 277 ) 89 - 94  2015.08

    J-GLOBAL

  • ベクトルビーム制御によるスナップショットTHz偏光検出

    若山俊隆, 東口武史, 東口武史, 及川大基, 坂上和之, 鷲尾方一, 米村元喜, 吉澤徹, SCOTT Tyo, 大谷幸利

    光学シンポジウム講演予稿集   40th   49 - 50  2015.06

    J-GLOBAL

  • 電子線を用いた微細加工電解質膜に関する研究

    漆畑諒, 田倉貴史, 吉田智輝, 大島明博, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   52nd   15  2015.06

    J-GLOBAL

  • 収束電子ビームを用いた高強度レーザーのプロファイル計測に関する研究

    五十嵐大裕, 佐藤令, 野々村洸, 坂上和之, 遠藤彰, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   52nd   21  2015.06

    J-GLOBAL

  • パルスラジオリシスシステム高度化のためのCPAレーザー増幅システムの開発

    添田雄史, 伊藤孔明, WANG Chucheng, 保坂勇志, 坂上和之, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   52nd   19  2015.06

    J-GLOBAL

  • DDSナノデバイス開発に向けた温度応答性膜の作製―電子線グラフト重合法を利用したフッ素系高分子に対する温度応答性高分子の付与に関する研究―

    山原有未, 高橋篤史, 大島明博, 鷲尾方一, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   52nd   13  2015.06

    J-GLOBAL

  • Demonstration of the stabilization technique for nonplanar optical resonant cavities utilizing polarization

    T. Akagi, S. Araki, Y. Funahashi, Y. Honda, S. Miyoshi, T. Okugi, T. Omori, H. Shimizu, K. Sakaue, T. Takahashi, R. Tanaka, N. Terunuma, Y. Uesugi, J. Urakawa, M. Washio, H. Yoshitama

    REVIEW OF SCIENTIFIC INSTRUMENTS   86 ( 4 )  2015.04

     View Summary

    Based on our previously developed scheme to stabilize nonplanar optical resonant cavities utilizing polarization caused by a geometric phase in electromagnetic waves traveling along a twisted path, we report an application of the technique for a cavity installed in the Accelerator Test Facility, a 1.3-GeV electron beam accelerator at KEK, in which photons are generated by laser-Compton scattering. We successfully achieved a power enhancement of 1200 with 1.4% fluctuation, which means that the optical path length of the cavity has been controlled with a precision of 14 pm under an accelerator environment. In addition, polarization switching utilizing a geometric phase of the nonplanar cavity was demonstrated. (C) 2015 AIP Publishing LLC.

    DOI

  • 電子バンチ傾き制御によるコヒーレントチェレンコフ放射に関する研究

    坂上和之, 浦川順治, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   70 ( 1 ) ROMBUNNO.22PDE-6  2015.03

    J-GLOBAL

  • 光共振器を用いたパルスレーザーの繰り返し逓倍化に関する研究

    小林岳周, 鈴木里佳, 坂上和之, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   70 ( 1 ) ROMBUNNO.22ADE-6  2015.03

    J-GLOBAL

  • 早稲田大学におけるスーパーコンティニウム光を用いたパルスラジオリシスシステム開発

    伊藤孔明, 添田雄史, 保坂勇志, 坂上和之, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   70 ( 1 ) ROMBUNNO.22PDE-5  2015.03

    J-GLOBAL

  • Cs‐Teフォトカソードの高度化に関する研究

    松崎脩理, 西田万里子, 坂上和之, 飯島北斗, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   70 ( 1 ) ROMBUNNO.22ADE-8  2015.03

    J-GLOBAL

  • KEK小型電子加速器におけるレーザー蓄積装置を用いた小型X線源(LUCX)の開発(16)

    福田将史, 荒木栄, ARYAHEV Alexander, 浦川順治, 坂上和之, 照沼信浩, 本田洋介, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   70 ( 1 ) ROMBUNNO.24PDE-6  2015.03

    J-GLOBAL

  • レーザーコンプトン光源のための自発共鳴型光蓄積空洞の開発

    上杉祐貴, 赤木智哉, 荒木栄, 浦川順治, 大森恒彦, 奥木敏行, 小菅淳, 坂上和之, 高橋徹, 田中龍太, 照沼信浩, 保坂勇志, 本田洋介, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   70 ( 1 ) ROMBUNNO.24PDE-2  2015.03

    J-GLOBAL

  • RF‐Defiectorを用いたフォトカソードRF‐GunにおけるBunching factorの計測

    筧田知慶, 高橋猛之進, 西山将大, 野々村洸, 坂上和之, 鷲尾方一, 高富俊和, 浦川順治

    日本物理学会講演概要集(CD-ROM)   70 ( 1 ) ROMBUNNO.22PDE-2  2015.03

    J-GLOBAL

  • モード同期Ybファイバーレーザーを用いたカソード照射用レーザーシステムの開発

    鈴木里佳, 坂上和之, 遠藤彰, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   70 ( 1 ) ROMBUNNO.22ADE-7  2015.03

    J-GLOBAL

  • 収束電子ビームを用いた金属ワイヤの2次元CTプロファイル計測原理実証

    五十嵐大裕, 佐藤令, 野々村洸, 坂上和之, 遠藤彰, 鷲尾方一

    日本物理学会講演概要集(CD-ROM)   70 ( 1 ) ROMBUNNO.24PDE-7  2015.03

    J-GLOBAL

  • 高分子中での電子線グラフト重合における空間的な反応の広がりに関する研究

    漆畑諒, 田倉貴史, 塚本淳志, 酒井祐輔, 大島明博, 鷲尾方一

    日本化学会講演予稿集   95th ( 2 ) 482  2015.03

    J-GLOBAL

  • PEFC用の低・無加湿下発電における薄膜化された有機無機ハイブリッド電加湿膜の開発

    田倉貴史, 塚本淳志, 酒井祐輔, 花崎祐, 吉田智輝, 大島明博, 鷲尾方一

    日本化学会講演予稿集   95th ( 2 ) 482  2015.03

    J-GLOBAL

  • DDSナノデバイス開発に向けた電子線グラフト重合法による温度応答性膜の作製

    山原有未, 高橋篤史, 大島明博, 鷲尾方一

    日本化学会講演予稿集   95th ( 2 ) 482  2015.03

    J-GLOBAL

  • テラヘルツビームの偏光検出:ベクトル渦解析 III

    若山俊隆, 東口武史, 及川大基, 坂上和之, 鷲尾方一, 米村元喜, 吉澤徹, SCOTT Tyo, 大谷幸利

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   62nd   ROMBUNNO.14A-A12-5  2015.02

    J-GLOBAL

  • テラヘルツベクトルビームの制御 II

    若山俊隆, 東口武史, 及川大基, 坂上和之, 鷲尾方一, 米村元喜, 吉澤徹, SCOTT Tyo, 大谷幸利

    応用物理学会春季学術講演会講演予稿集(CD-ROM)   62nd   ROMBUNNO.14A-A12-4  2015.02

    J-GLOBAL

  • レーザーコンプトン光源のためのパルス型自発共鳴型光蓄積共振器の開発

    保坂勇志, 赤木智哉, 浦川順治, 大森恒彦, 小菅淳, 本田洋介, 上杉祐貴, 高橋徹, 坂上和之, 鷲尾方一

    日本加速器学会年会(Web)   12th   THP111 (WEB ONLY)  2015

    J-GLOBAL

  • KEK小型電子加速器(LUCX)の現状報告(8)

    福田将史, 荒木栄, 浦川順治, 坂上和之, 照沼信浩, 本田洋介, 鷲尾方一

    日本加速器学会年会(Web)   12th   WEP131 (WEB ONLY)  2015

    J-GLOBAL

  • 傾き制御電子バンチによるコヒーレントテラヘルツ光発生

    坂上和之, 西田万里子, 水柿将貴, 鷲尾方一, 浦川順治, 黒田隆之助, 平義隆

    日本加速器学会年会(Web)   12th   WEP097 (WEB ONLY)  2015

    J-GLOBAL

  • パルスラジオリシスシステム改善のためのフェムト秒ファイバレーザの開発

    添田雄史, 伊藤孔明, 斎藤悠太郎, 保坂勇志, 坂上和之, 鷲尾方一

    日本加速器学会年会(Web)   12th   THP112 (WEB ONLY)  2015

    J-GLOBAL

  • 22pDE-2 Measurement of bunching factor in a photocathode RF-gun using RF-deflector

    Toida T, Takahashi T, Nishiyama M, Nonomura K, Sakaue K, Washio M, Takatomi T, Urakawa J

    Meeting Abstracts of the Physical Society of Japan   70 ( 0 ) 532 - 532  2015

    DOI CiNii

  • Demonstration of an optical enhancement cavity with 10 micron wavelength

    K. Sakaue, M. Washio, A. Endo

    HIGH-POWER, HIGH-ENERGY, AND HIGH-INTENSITY LASER TECHNOLOGY II   9513  2015

     View Summary

    We have been developing a pulsed-laser optical enhancement cavity for laser-Compton scattering (LCS). LCS can produce high brightness X-ray through the collision between relativistic electrons generated from the accelerator and high power laser photons with a compact facility. In order to increase the number of collisions/sec, high repetition rate accelerator and laser are required. For the laser system, an optical enhancement cavity is the most powerful tool for LCS, thus we have been developing the cavity for storing 1 micron laser pulse. On the other hand, the resulting X-ray energy can be changed by the collision laser wavelength. If we have another optical cavity with different wavelength, the multicolor, quasi-monochromatic, high brightness and compact X-ray source can be realized. Therefore, we started to develop an optical cavity at 10 micron wavelength with CO2 laser. At this wavelength region, the absorption loss is dominant compared with scattering loss. Thus we carefully chose the optical mirrors for enhancement cavity. We demonstrated a more than 200 enhancement factor with 795 finesse optical cavity at 10 micron CO2 laser. Moreover, 2.3 kW storage in the optical cavity was successfully demonstrated. The design of optical cavity, first experimental results and future prospects will be presented at the conference.

    DOI

  • Development of a mode-locked fiber laser system for a high finesse enhancement cavity

    R. Suzuki, T. Kobayashi, K. Sakaue, M. Washio, A. Endo

    HIGH-POWER, HIGH-ENERGY, AND HIGH-INTENSITY LASER TECHNOLOGY II   9513  2015

     View Summary

    We have been studying a high finesse enhancement cavity for photon target of Laser Compton Scattering X-ray generation. It is very important to develop an extremely stable external optical cavity for laser Compton scattering. At the same time, a stable seed laser oscillator for an incident laser of an optical cavity is also very important tissue. Thus, we have been developing a stabil mode-locked Yb-doped fiber laser based on Non-Linear Polarization Rotation. We have generated laser pulses which have 102.9mW average power at repetition rate of 119MHz. Furthermore, we started accumulating lasers in the optical cavity, and we have already confirmed that our oscillator is able to accumulate in the cavity.

    DOI

  • Laser-Compton scattering X-ray source based on normal conducting linac and optical enhancement cavity

    K. Sakaue, M. Washio, S. Araki, M. Fukuda, Y. Honda, N. Terunuma, J. Urakawa

    6th International Particle Accelerator Conference, IPAC 2015     1635 - 1637  2015.01

     View Summary

    Copyright © 2015 CC-BY-3.0 and by the respective authors. We have been developing a compact X-ray source via laser-Compton scattering (LCS) at KEK-LUCX (Laser Undulator Compact X-ray source) facility. The LUCX system is based on S-band normal conducting linac with an energy of 30 MeV and optical enhancement cavity for photon target. As a photon target, we invented a burst mode laser pulse storage technique for a normal conducting linac, which enables to store the high power laser pulses at the timing of electron bunches. The peak storage power exceeds to more than 250 kW with 357 MHz repetition. Electron linac is under operation with multi-bunch mode, 1000 bunches/train with 600 pC charge in each bunches. We have succeeded to produce 1000 pulse/train LCS X-ray train. Combining high repetition rate electron linac and burst mode optical enhancement cavity, more than 109 ph./sec/10% b.w. flux would be possible. In this conference, the introduction of our test facility LUCX, recent experimental results, and future prospective including normal conducting LCS X-ray source will be presented.

  • Study on frequency multiplier of a pulsed laser repetition using an optical cavity

    T. Kobayashi, R. Suzuki, K. Sakaue, M. Washio

    6th International Particle Accelerator Conference, IPAC 2015     1629 - 1631  2015.01

     View Summary

    Copyright © 2015 CC-BY-3.0 and by the respective authors. We have been studying a compact electron accelerator based on an S-band Cs-Te photo-cathode rf gun at Waseda University. The system is using S-band rf of 2856MHz. When a repetition of the electron bunch is integral multiple of rf, it enables a lot of electron bunch acceleration for the rf gun. The repetition of the electron bunch generated by a photo-cathode rf gun depends on the oscillating frequency of the pulsed mode-locked laser. We have been developing a mode-locked Yb-doped fiber laser based on Non-Linear Polarization Rotation (NLPR). However, its repetition is limited by the fiber length to produce NLPR. So we have started to develop the external optical cavity which is multiplier of a pulsed laser repetition. It would enable the rf gun to generate high-dose electron beam in a very short time. In this conference, we will report design of the external optical cavity to multiply the pulsed laser repetition, the experimental results of the frequency multiplying of a mode-locked Yb-doped fiber laser, and the future prospects.

  • Generation of multi-bunch beam with beam loading compensation by using RF amplitude modulation in Laser Undulator Compact X-ray (LUCX)

    M. Fukuda, S. Araki, Y. Honda, N. Terunuma, J. Urakawa, K. Sakaue, M. Washio

    6th International Particle Accelerator Conference, IPAC 2015     1576 - 1578  2015.01

     View Summary

    Copyright © 2015 CC-BY-3.0 and by the respective authors. We have been developing a compact X-ray source based on inverse Compton scattering (ICS) between an electron beam and a laser pulse stacked in an optical cavity at Laser Undulator Compact X-ray (LUCX) accelerator in KEK. The accelerator consists of a 3.6-cell photo-cathode rf-gun, a 12-cell standing wave accelerating structure and a 4-mirror planar optical cavity. Our aim is to obtain a clear X-ray image in a shorter period of times and the target flux of X-ray is 1.7×107photons/pulse with 10% bandwidth at present. To achieve this target, it is necessary to increase the intensity of an electron beam to 500 nC/pulse with 1000 bunches at 30 MeV. Presently, we have achieved the generation of 24 MeV beam with total charge of 600 nC in 1000 bunches with the bunch-by-bunch energy difference is within 1.3% peak to peak. The beam-loading has been compensated by injecting the beam before rf power has been filled (ΔT method) and by modulating the amplitude of the rf pulse. We report the results of the multi-bunch beam generation and acceleration in the LUCX accelerator.

  • Development of a pulse radiolysis system by ultra-fast super continuum probe light at Waseda University

    Y. Ito, Y. Soeta, Y. Hosaka, K. Sakaue, M. Washio

    6th International Particle Accelerator Conference, IPAC 2015     2265 - 2267  2015.01

     View Summary

    Copyright © 2015 CC-BY-3.0 and by the respective authors. We have been studying the pulse radiolysis using photo-cathode rf gun at Waseda Univ. Pulse radiolysis is one of the powerful methods to trace early chemical reactions by ionizing radiation. In pulse radiolysis, the probe light absorption, which produced by active species formed by electron beam of rf gun, is measured at each wavelength and made possible to trace reactions. Therefore, we have used the super continuum (SC) light for the probe light. The SC light has a broad spectrum and is generated by nonlinear optical effect caused by injecting picosecond laser to photonic crystal fiber (PCF). However, the resulting SC light was unstable because its peak intensity was not enough. We need to use a femtosecond pulsed laser which is expected to be stronger peak intensity than a picosecond laser. We have developed a mode-locked Yb-doped fiber laser based on Non-Linear Polarization Rotation as a femtosecond pulsed laser and the chirped pulse amplification system which will be able to amplify the femtosecond pulse. In this conference, we will report the performance of the SC light using this fiber laser system, recent results of pulse radiolysis experiments and the future plans.

  • Study of Cs-Te photocathode for rf electron gun

    Shuri Matsuzaki, Mariko Nishida, Kazuyuki Sakaue, Masakazu Washio, Hokuto Iijima

    6th International Particle Accelerator Conference, IPAC 2015     1632 - 1634  2015.01

     View Summary

    Copyright © 2015 CC-BY-3.0 and by the respective authors. At Waseda University, we have been studying high quality electron beam with an rf electron gun. In recent accelerator study and application researches, high quality electron beam are strongly required. Photocathode is a key component to generate higher quality electron beam, thus we started to develop a Cs-Te photocathode as an electron source since 2007. Cs-Te photocathode shows high quantum efficiency (Q.E.) (∼10 %) and has long life time (∼several months). From 2013, we built a photocathode evaporation chamber and started photocathode study. In this study, our purpose is to clarify their property and to establish an ideal evaporation recipe. We succeeded in producing high quality Cs-Te photocathode, and electron beam generated by our Cs-Te photocathode shows high charge (4.6 nC/bunch) and high Q.E. (1.74 %) in our rf electron gun. Furthermore, we found a Q.E recovery after Cs deposition process and it causes higher Q.E. than usual due to, we believe, Cs deposition quantity or Cs deposition speed. Thus we are now surveying the optimum Cs evaporation parameters. In this conference, we will report a detail of our photocathode development system, the latest progress of optimization study of Cs-Te photocathode and future plans.

  • Characterization of THz radiation generated by ultra-short bunch from energy chirping cell attached RF electron gun

    Y. Koshiba, K. Sakaue, M. Mizugaki, M. Washio, R. Kuroda, T. Takatomi, J. Urakawa

    VIBRATIONAL SPECTROSCOPY   75   184 - 189  2014.11

     View Summary

    The coherent radiation spectrum extends into the far-infrared/THz region when the electron bunch is shorter than 1 Ps (0.3 mm). Such ultra-short electron bunches can be produced using a variety of bunching schemes in electron accelerators. We have designed a photocathode RF electron gun, named ECC RF gun, specifically for ultra-short bunch generation. ECC stands for energy chirping cell. This paper describes the brief principle of the ECC RF gun, CTR (coherent transition radiation) observation using Schottky barrier diodes (SBD) and spectrum measurement using interferometry with SBDs. We have successfully confirmed the generation of 0.05-0.3 THz high peak power pulsed CTR. (C) 2014 Elsevier B.V. All rights reserved.

    DOI

  • Design of a two-cell rf-deflector cavity for ultra-short electron bunch measurement

    Y. Nishimura, K. Sakaue, M. Nishiyama, T. Takahashi, M. Washio, T. Takatomi, J. Urakawa

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   764   291 - 298  2014.11

     View Summary

    For a longitudinal characterization of an ultra-short electron bunch, an rf-deflector cavity is the best resolution technique that can directly convert longitudinal distribution to transverse. This paper describes the principle of longitudinal diagnostics using an rf-deflector cavity, the design details of an rf-deflector cavity and the results of rf-characteristics for a manufactured cavity. The cavity is based on a rectangular two-cell structure operating on standing wave pi-mode, dipole (TM120) mode at 2856 MHz. We have confirmed using HFSS simulation that this cavity can produce a deflecting voltage of 1.63 MV with an input rf-power of 750 kW. The results of low power rf-measurement of the manufactured cavity show an effective deflecting voltage of 1.00 MV which corresponds to a temporal resolution of 58 fs (rms) (250 fs/mm on the profile monitor) with 750 kW input rf-power, drift length L of 1 m and initial size sigma(off) of 230 mu m. These results indicate that we have successfully achieved our target: temporal resolution of less than 100 fs with an electron bunch with energy of 4.5 MeV and charge of 100 pC. (C) 2014 Elsevier B.V. All rights reserved.

    DOI

  • Fabrication of nano space controlled materials using high‐energy heavy ion irradiation

    鷲尾方一, 大島明博, 濱義昌, 坂上和之, 岡壽崇, 村上健

    NIRS-M (National Inst. of Radiological Sciences)   ( 273 ) 188 - 189  2014.10

    J-GLOBAL

  • 早稲田大学におけるパルスラジオリシスシステム開発

    伊藤孔明, WANG Chuchng, 坂本瑞樹, 保坂勇志, 坂上和之, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   51st   33  2014.06

    J-GLOBAL

  • RF偏向空洞を用いた電子ビームの時間方向分布計測

    西山将大, 西村祐一, 高橋猛之進, 坂上和之, 鷲尾方一, 高富俊和, 浦川順治

    アイソトープ・放射線研究発表会要旨集   51st   96  2014.06

    J-GLOBAL

  • Fabrication of Function-Graded Proton Exchange Membranes for Direct Methanol Fuel Cells Using Electron Beam-Grafting

    R. Tsuchida, S. Hiraiwa, A. Tsukamoto, M. Washio, A. Oshima

    FUEL CELLS   14 ( 2 ) 284 - 290  2014.04

     View Summary

    Function-graded proton exchange membranes (G-PEMs) based on poly(tetrafluoroethylene-co-hexafluoropropylene) were fabricated for direct methanol fuel cells (DMFCs) via electron beam-grafting using the heterogeneous energy deposition technique. The G-PEMs had a water uptake gradient in the proton transfer direction, originating from the sulfonic acid group gradient. The distribution of sulfonic acid groups in the various G-PEMs was evaluated using X-ray photoelectron spectroscopy. Four types of PEMs (flat-type, strong-gradient, meso-gradient, and weak-gradient types) were fabricated. By varying the direction of the G-PEMs, the methanol permeation test and DMFC operation were performed with two orientations of the sulfonic acid group gradient, decreasing from the methanol injection (anode) side (decrease-type) or the other (cathode) side (increase-type). The methanol permeability of the strong-gradient, meso-gradient, and weak-gradient G-PEMs was lower than that of Nafion (R) 117 and the flat-type PEM. The increase-type orientation of the strong-gradient G-PEM resulted in the lowest methanol permeability. The DMFC performance of the G-PEMs was influenced by the thickness direction, such as decrease-type and increase-type. The performance of the decrease-type assembly was higher than that of the increase-type. The decrease-type assembly with P-200 k (weak-gradient G-PEM) exhibited the highest performance of the fabricated PEMs, comparable to that of Nafion (R) 117.

    DOI

  • レーザーコンプトン散乱による小型高輝度光子ビーム源の開発

    上杉祐貴, 赤木智哉, 荒木栄, 浦川順治, 大森恒彦, 奥木敏行, 栗木雅夫, 坂上和之, 清水洋孝, 高橋徹, 田中龍太, 照沼信浩, 舟橋義聖, 本田洋介, 吉玉仁, 鷲尾方一

    日本物理学会講演概要集   69 ( 1 ) 26  2014.03

    J-GLOBAL

  • Ultrashort electron bunch generation by an energy chirping cell attached rf gun

    K. Sakaue, Y. Koshiba, M. Mizugaki, M. Washio, T. Takatomi, J. Urakawa, R. Kuroda

    PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS   17 ( 2 )  2014.02

     View Summary

    We present a new design for a rf electron gun to be used in ultrashort (similar to 1 ps) electron bunch generation. Using both simulation and measurement we evaluated the principle of this new type rf gun and were able to confirm an ultrashort bunch generation. During simulation, a bunch length of less than 100 fs(rms) with a 100 pC/bunch charge was confirmed at the optimum operating condition. The principle is to produce a linearly distributed longitudinal phase space by using an attached output cell specially designed for energy chirping. Such phase space distribution can be rotated by the velocity difference in the bunch. We already fabricated an energy chirping cell attached rf gun and successfully observed 0.2 THz coherent synchrotron radiation, which corresponds to less than 500 fs bunch. Such an electron gun can be used as a compact THz light source and a new electron injector with an ultrashort bunch.

    DOI

  • NLPR法を用いたモード同期Ybファイバーレーザーの開発

    鈴木里佳, 坂本瑞樹, 坂上和之, 鷲尾方一

    日本加速器学会年会(Web)   11th   SUP112 (WEB ONLY)  2014

    J-GLOBAL

  • 2‐Cell RF Deflectorを用いた電子ビームの時間構造計測

    西山将大, 西村祐一, 高橋猛之進, 筧田知慶, 坂上和之, 鷲尾方一, 高富俊和, 浦川順治

    日本加速器学会年会(Web)   11th   SUP082 (WEB ONLY)  2014

    J-GLOBAL

  • 収束電子ビームを用いた高強度レーザーの直接プロファイル計測法の開発

    佐藤令, 野々村洸, 五十嵐大祐, 坂上和之, 遠藤彰, 鷲尾方一

    日本加速器学会年会(Web)   11th   SAP115 (WEB ONLY)  2014

    J-GLOBAL

  • KEK小型電子加速器(LUCX)の現状報告(7)

    福田将史, 荒木栄, ARYSHEV Alexander, 浦川順治, 坂上和之, 照沼信浩, 本田洋介, 鷲尾方一

    日本加速器学会年会(Web)   11th   SUP122 (WEB ONLY)  2014

    J-GLOBAL

  • 早稲田大学におけるCs‐Teフォトカソードの開発

    松崎脩理, 坂本瑞樹, 西田万里子, 坂上和之, 鷲尾方一, 浦川順治

    日本加速器学会年会(Web)   11th   SUP032 (WEB ONLY)  2014

    J-GLOBAL

  • エネルギー変調セル付属型高周波電子銃の開発と利用展開

    坂上和之, 立花充章, 水柿将貴, 鷲尾方一, 浦川順治, 黒田隆之助

    日本加速器学会年会(Web)   11th   SUP044 (WEB ONLY)  2014

    J-GLOBAL

  • 27aTM-7 Development of a 2 Cell RF-Deflector for longitudinal electron beam profile measurement

    Nishiyama Masahiro, Nishimura Yuichi, Takahashi Takenoshin, Sakaue Kazuyuki, Washio Masakazu, Takatomi Toshikazu, Urakawa Junji

    Meeting Abstracts of the Physical Society of Japan   69 ( 0 ) 138 - 138  2014

    CiNii

  • 27pTJ-8 Development of high brightness photon source by using laser Compton scattering

    Uesugi Y, Takahashi T, Tanaka R, Terunuma N, Funahashi Y, Honda Y, Yoshitama H, Washio M, Akagi T, Araki S, Urakawa J, Omori T, Okugi T, Kuriki M, Sakaue K, Shimizu H

    Meeting Abstracts of the Physical Society of Japan   69 ( 0 ) 26 - 26  2014

    CiNii

  • 27aTM-3 Development of Compact X-ray Source with a Pulsed Laser Cavity in LUCX(14)

    Fukuda Masafumi, Akagi Tomoya, Araki Sakae, Aryshev Alexander, Urakawa Junji, Sakaue Kazuyuki, Terunuma Nobuhiro, Honda Yosuke, Washio Masakazu

    Meeting Abstracts of the Physical Society of Japan   69 ( 0 ) 137 - 137  2014

    CiNii

  • 27aTM-4 Development of a compact X-ray source using an optical enhancement cavity at KEK-LUCX

    Sakaue Kazuyuki, Araki Sakae, Aryshev Alexander, Urakawa Junji, Terunuma Nobuhiro, Fukuda Masafumi, Honda Yosuke, Washio Masakazu

    Meeting Abstracts of the Physical Society of Japan   69 ( 0 ) 137 - 137  2014

    CiNii

  • 18aSH-6 Efforts to high Finesse of laser cavity for polarized positron source

    Tanaka R, Takahashi T, Terunuma N, Funahashi Y, Honda Y, Washio M, Akagi T, Araki S, Uesugi Y, Urakawa J, Omori T, Okugi T, Sakaue K, Shimizu H

    Meeting Abstracts of the Physical Society of Japan   69 ( 0 ) 17 - 17  2014

    CiNii

  • Evaluation of vacancies in positive-tone non-chemically and chemically amplified EUV/EB resists Relationship between free-volume and LER

    Akihiro Oshima, Toru Hinata, Hirotaka Nakamura, Toshitaka Oka, Nagayasu Oshima, Brian E. O'Rourke, Ryoichi Suzuki, Masakazu Washio, Seiichi Tagawa

    ADVANCES IN PATTERNING MATERIALS AND PROCESSES XXXI   9051  2014

     View Summary

    EUV, X-ray and EB mainly induce ionization in resist materials and its energy deposition process is different from ArF exposure. Linear energy transfer (LET) effect for resist sensitivity is very important issue from the viewpoint of radiation induced chemical reactions for high-volume nanofabrication. Therefore the knowledgebase of radiation chemistry is required for understanding the resist performances for EUV lithography. In order to acquire the knowledge of resist materials for EUV / EB lithography from a viewpoint of the free-volume, the positron annihilation lifetime spectroscopy was carried out using positron probe microanalyzer (PPMA) installed at AIST. The size of free-volume can be evaluated from the lifetime of ortho-Positronium (o-Ps). The lifetime and intensity of o-Ps in EB-exposed positive-tone non-chemically amplified (non-CA, ZEP) and CA (UV-III) EUV / EB resists were observed. Moreover, to evaluate the relationship between line edge roughness (LER) and free-volume, EB lithography was carried out, and then sensitivities (E-0 and E-size) and LER were measured. For both non-CA and CA resist materials, the changes of free-volume due to evaporation of outgas, polarity change or chain scission would hardly influence on their LER and resolution.

    DOI

  • Cryogenically cooled 1J, PS YB:YAG Slab laser for high-brightness laser-compton X-ray source

    Akira Endo, Pawel Sikocinski, Michal Chyla, Taisuke Miura, Tomas Mocek, Kazuyuki Sakaue, Masakazu Washio

    IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference     2056 - 2058  2014.01

     View Summary

    Copyright © 2014 CC-BY-3.0 and by the respective authors. A prototype solid state picosecond laser is reported for single shot laser-Compton bio-imaging applications. The target specification is 1J, 1ps at 120Hz with good beam quality for precise pointing to 10 μm focused 43MeV electron beam with 1nC charge. 0.1J stretched pulse is obtained from a thin disc Yb:YAG laser, and amplified through a cryogenically cooled Slab Yb: YAG module in a multipass configuration. Temperature dependent gain characteristics is analysed and concluded as the designed optimization is sufficient for long time stable operation for the laser-Compton imaging.

  • Bunch length measurement with 2-cell rf-deflector at Waseda University

    T. Takahashi, Y. Nishimura, M. Nishiyama, K. Sakaue, M. Washio, T. Takatomi, J. Urakawa

    IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference     3556 - 3558  2014.01

     View Summary

    Copyright © 2014 CC-BY-3.0 and by the respective authors. We have been studying on a system to measure the length of electron bunch generated by a photocathode rf electron gun at Waseda University. We adopted the rf-deflector system which can convert the longitudinal distribution to transverse by sweeping the electron bunch. By using HFSS, we optimized the design of the 2 cell rf-deflector which is operating on π-mode, dipole (TM210) mode at 2856 MHz. The fabrication and the tuning of the rf deflector have successfully processed. We have installed the rf-deflector in the accelerator system of Waseda University, and performed the measurement of the bunch length. It is confirmed that this rf-deflector has the temporal resolution of 167fs with 700kW supply when the beam energy is 4.8MeV. This means that our rf-deflector system has possibility to measure the ultra-short bunch length. In this conference, the rf-deflector system in Waseda University, the result of the bunch length measurement, the performance of the rf-deflector and the future plan will be reported.

  • Direct high power laser diagnostic technique based on focused electron bunch

    R. Sato, Y. Yoshida, K. Nonomura, K. Sakaue, A. Endo, M. Washio

    IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference     2242 - 2244  2014.01

     View Summary

    Copyright © 2014 CC-BY-3.0 and by the respective authors. In laser produced plasma EUV source, high intensity pulse CO&lt;inf&gt;2&lt;/inf&gt; laser is essential for plasma generation. To achieve high conversion efficiency and stable EUV power, we desire to measure laser profile at the collision point. However, focused laser profile has not been observed directory by existing techniques. We have been developing laser profiler based on laser Compton scattering. Laser profile can be measured by scanning focused electron beam while measuring Compton scattering signal. This method is suitable for a high intensity laser, but very small spot size of electron beam is required. To achieve small spot size, we use S-band photocathode rf gun and specially designed solenoid lens. The beam size was simulated by General particle tracer (GPT) and directory measured by Gafchromic film HD-810. We have succeeded in observing minimum beam size of about 20μm rms. We are preparing beam scanning system, pulse CO&lt;inf&gt;2&lt;/inf&gt; laser and a detector for Compton signal. In this conference, we will report the results of focused electron beam measurement and future prospect.

  • Ultra-short electron bunch generation using energy-chirping cell attached RF electron gun

    K. Sakaue, Y. Koshiba, M. Mizugaki, M. Washio, T. Takatomi, J. Urakawa, R. Kuroda

    IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference     685 - 687  2014.01

     View Summary

    Copyright © 2014 CC-BY-3.0 and by the respective authors. We have been developing an Energy-Chirping-Cell attached RF electron gun (ECC-rf gun) for generating ultrashort electron bunches. ECC-rf gun has extra cell at the end of gun cavity in order to chirp the bunch energy. Such a bunch can be compressed by the velocity difference though the drift space. We have already installed it to our accelerator system and successfully observed a coherent synchrotron/transition radiation at 0.3 THz. It is clear that the bunch length was short enough to generate 0.3 THz, which corresponds to less than 500 fs bunch length was achieved if we assume the gaussian shape. In this conference, the principle of ECC-rf gun, the recent results of bunch length measurement and future prospective will be presented.

  • Longitudinal diagnostics of RF electron gun using a 2-cell RF deflector

    M. Nishiyama, T. Takahashi, T. Toida, K. Sakaue, M. Washio, T. Takatomi, J. Urakawa

    Proceedings of the 36th International Free Electron Laser Conference, FEL 2014     929 - 932  2014.01

     View Summary

    Copyright © 2014 CC-BY-3.0 and by the respective authors. We have been studying a compact electron accelerator based on an S-band Cs-Te photocathode rf electron gun at Waseda University. We are using this high quality electron bunch for many application researches. It is necessary to measure the bunch length and temporal distribution for evaluating application researches and for improving an rf gun itself. Thus, we adopted the rf deflector system. It kicks the electron bunch with resonated rf electromagnetic field. Using this technique, the longitudinal distribution is mapped into the transverse space. The rf deflector has a 2-cell standing wave π-mode structure, operating in TM210 dipole mode at 2856 MHz. It provides a maximum vertical kick of 1.00MV with 750 kW input rf-power which is equivalent to the temporal resolution of around 58 fs bunch length. In this conference, we report the details of our rf deflector, the latest progress of longitudinal phase space diagnostics and future prospective.

  • Optimization of high average power FEL beam for EUV lithography application

    A. Endo, K. Sakaue, M. Washio, H. Mizoguchi

    Proceedings of the 36th International Free Electron Laser Conference, FEL 2014     990 - 992  2014.01

     View Summary

    Copyright © 2014 CC-BY-3.0 and by the respective authors. EUV source community is interested in evaluating an alternative method based on high repetition rate FEL, to avoid a risk of the potential source power limit by the plasma based technology. Present SASE FEL pulse (typically 0.1mJ, 100fs, 1 mm diameter) has higher beam fluence than the resist ablation threshold, and high spatial coherence which results in speckle and interference patterns, and random longitudinal mode spikes of high peak power micro pulses, which is not favourable to resist chemistry. This paper discusses on the required technological assessment and lowest risk approach to construct a prototype, based on superconducting linac and cryogenic undulator, to demonstrate a MHz repetition rate, high average power 13.5nm FEL equipped with specified optical components, for best optimization in EUVL application, including a scaling to 6.7nm wavelength region.

  • Ultra-short electron bunch generation by an ECC rf gun

    Y. Koshiba, T. Aoki, M. Mizugaki, K. Sakaue, M. Washio, T. Takatomi, J. Urakawa

    IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference     330 - 332  2013.12

     View Summary

    Energy Chirping Cell attached rf gun (ECC rf gun) is a photocathode rf gun specialized for ultra-short bunch generation. This ECC rf gun has been made with the collaboration of High Energy Accelerator Research Organization (KEK) [1] [2]. Although the bunch length could be controlled by the laser pulse width, the bunch length ends up to be more than 1 ps due to space charge effect when using a femto-second laser and a normal 1.6 cell cavity. Concerning this phenomenon, ECC is attached right after the 1.6 cell so that the electron bunch would be compressed after the electron bunch is accelerated around 5 MeV. The roll of ECC is to chirp the energy with the linear part of the rf electric field. The electron bunch would be compressed by velocity difference as it drifts. Simulation results from PARMELA and GPT show that the ECC rf gun can accelerate an 100 pC bunch with the bunch length less than 100 fs. We already manufactured this ECC rf gun and installed in our system. We demonstrated the ultra-short bunch by measuring the coherent THz light by synchrotron radiation and transition radiation. In this conference, we will report the results of ultra-short bunch generation experiments, and future plans. Copyright © 2013 by JACoW.

  • Direct diagnostic technique of high-intensity laser profile based on laser-compton scattering

    Y. Yoshida, R. Sato, K. Sakaue, A. Endo, M. Washio

    IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference     3657 - 3659  2013.12

     View Summary

    A high-intensity laser is essential for plasma generation for EUV (Extreme Ultraviolet) lithography, which is studied as the next generation of ultra-fine semiconductor lithography. Nevertheless, there is no way to directly measure profile of high-intensity laser at the present day. Therefore, we have been developing a method for measuring high-intensity laser profile based on the laser- Compton scattering using Cs-Te photo cathode RF-Gun at Waseda University. Specifically, laser profile is obtained by scanning the electron beam which is focused to about 10 μm by solenoid lens. We have simulated beam size focused by solenoid lens using tracking code GPT (General Particle Tracer) and optimized the beam parameter to obtain beam size of 10 μm. Then, we have installed solenoid lens and generated focused beam. We measured beam size using radiochromic film called GAFCHROMIC dosimetry film type HD-810. In this conference, we will report the result of GPT simulations, beam size measurements, the present progress and future prospects.

  • Development of laser-compton x-ray source using optical storage cavity

    K. Sakaue, M. Washio, M. Fukuda, Y. Honda, N. Terunuma, J. Urakawa

    IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference     2165 - 2167  2013.12

     View Summary

    We have been developing a pulsed-laser storage technique in a super-cavity for a compact x-ray sources. The pulsed-laser super-cavity enables to make high peak power and small waist laser at the collision point with the electron beam. We already obtained a pulse-train x-rays through the laser-Compton scattering between a multi-bunch electron beam and an optical super-cavity. And also, we performed a X-ray imaging via laser-Compton X-ray. On these successful results, we decided to upgrade our system for increasing X-ray flux by 3-order of magnitudes for practical use. For an optical cavity, we designed 4-mirrors bowtie cavity in order to increase the power. On the other hand, electron accelerator was also upgraded to increase the bunch number in the train. We use 3.6cells rf-gun and 12cell standing wave booster linac. As a result, 2-order increase of X-ray flux was achieved. Design of upgraded our laser-Compton X-ray source, the results of X-ray experiments and future prospective will be presented at the conference. Copyright © 2013 by JACoW- cc Creative Commons Attribution 3.0 (CC-BY-3.0).

  • Development of CO<inf>2</inf>laser optical enhancement cavity for a laser-Compton X-ray source

    K. Ando, N. Takeichi, K. Sakaue, A. Endo, M. Washio

    IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference     2974 - 2976  2013.12

     View Summary

    We have been developing a laser-Compton X-ray source using an optical enhancement cavity. We have studied 1um pulse laser storage in optical cavity and use for the experiments. Usage of 10 um laser for optical enhancement cavity will increase the X-ray energy region of one laser-Compton X-ray source, so that we decided to develop the optical cavity for CO2laser. We have designed external optical cavity for CO2laser commercially available optics and verified the enhancement of CO2laser in external enhancement optical cavity, and measured fundamental parameters such as finesse, matching efficiency, and enhancement factor. We have already achieved 475 of finesse, 43 of enhancement, and tested non-planer cavity, which storages two circular polarization separately. In this conference, we will report the design and experimental results of CO2laser storage cavity and also some future prospects. Copyright © 2013 by JACoW- cc Creative Commons Attribution 3.0 (CC-BY-3.0).

  • 加速器をベースとしたBeyond EUV光源の検討

    坂上和之, 鷲尾方一, 遠藤彰

    レーザー学会研究会報告   450th   13 - 17  2013.10

    J-GLOBAL

  • Shorter Wavelength Light Sources by Plasmas and Quantum Beams

    HIGASHIGUCHI Takeshi, OTSUKA Takamitsu, UGOMORI Teruyuki, FUJIOKA Shinsuke, NISHIMURA Hiroaki, SUZUKI Chihiro, SAKAUE Kazuyuki, WASHIO Masakazu, ENDO Akira

    プラズマ・核融合学会誌   89 ( 10 ) 669 - 676  2013.10

     View Summary

    最近になって,ポストEUVリソグラフィ露光光源波長として,6.x nmの波長が注目され始めている.ハーフピッチが16nm以下になると,これまで開発されてきた13.5nmの光源では開口数や多層膜鏡,マスクまで設計から製造まで高度に改善することが求められるからである.そこで,解像度を上げるために,更なる短波長光源が必要になってくる可能性があるというわけである.ここでは,ポストEUV光源としての波長6.x nm光源の進展について紹介することにする.

    CiNii

  • パルスラジオリシス法によるポジ型塩素系電子線レジストの反応機構の研究

    保坂勇志, 坂本瑞樹, 大山智子, 榎本智至, 大島明博, 鷲尾方一, 田川精一

    放射線化学討論会講演要旨集   56th   31 - 32  2013.09

    J-GLOBAL

  • 極短バンチ生成用RF‐Gunの現状

    小柴裕也, 水柿将貴, 坂上和之, 鷲尾方一, 黒田隆之助, 高富俊和, 浦川順治

    放射線化学討論会講演要旨集   56th   25 - 26  2013.09

    J-GLOBAL

  • 早稲田大学パルスラジオリシスシステムの現状及び評価

    坂本瑞樹, 保坂勇志, 川内洋平, 坂上和之, 鷲尾方一

    放射線化学討論会講演要旨集   56th   143 - 144  2013.09

    J-GLOBAL

  • Fabrication of nano space controlled materials using high‐energy heavy ion irradiation

    鷲尾方一, 濱義昌, 坂上和之, 工藤久明, 岡壽崇, 大島明博, 村上健

    NIRS-M (National Inst. of Radiological Sciences)   ( 260 ) 214 - 215  2013.08

    J-GLOBAL

  • 極短バンチ生成用高周波電子銃の開発

    小柴裕也, 水柿将貴, 坂上和之, 鷲尾方一, 黒田隆之助, 高富俊和, 浦川順治

    アイソトープ・放射線研究発表会要旨集   50th   75  2013.06

    J-GLOBAL

  • KEK‐LUCXにおけるレーザーコンプトン散乱小型X線源の開発

    坂上和之, ARYSHEV Alexander, 荒木栄, 浦川順治, 武田彩希, 照沼信浩, 福田将史, 三好敏喜, 鷲尾方一

    加速器   10 ( 1 ) 32 - 42  2013.04

    J-GLOBAL

  • 偏極陽電子源の為のレーザーコンプトン散乱によるガンマ線生成実験

    田中龍太, 赤木智哉, 荒木栄, 浦川順治, 大森恒彦, 奥木敏行, 栗木雅夫, 坂上和之, 清水洋孝, 高橋徹, 照沼信浩, 舟橋義聖, 本田洋介, 吉玉仁, 鷲尾方一

    日本物理学会講演概要集   68 ( 1 ) 39  2013.03

    J-GLOBAL

  • 極短バンチ生成用高周波電子銃の開発

    水柿将貴, 小柴裕也, 坂上和之, 高富俊和, 黒田隆之助, 浦川順治, 鷲尾方一

    日本物理学会講演概要集   68 ( 1 ) 141  2013.03

    J-GLOBAL

  • 内部フレネル反射を用いたテラヘルツ・ベクトルビームの発生とその偏光解析

    若山俊隆, 坂上和之, 東口武史, 大谷幸利, 鷲尾方一, 米村元喜, 吉澤徹

    Optics &amp; Photonics Japan講演予稿集(CD-ROM)   2013   ROMBUNNO.12AE8  2013

    J-GLOBAL

  • フォトカソード高周波電子銃による極短バンチ生成実験

    水柿将貴, 小柴裕也, 坂上和之, 鷲尾方一, 高富俊和, 浦川順治, 黒田隆之助

    日本加速器学会年会(Web)   10th   SUP008 (WEB ONLY)  2013

    J-GLOBAL

  • レーザーコンプトン散乱を用いた高強度レーザーの直接プロファイル計測

    吉田靖史, 佐藤令, 野々村洸, 坂上和之, 遠藤彰, 鷲尾方一

    日本加速器学会年会(Web)   10th   SAP109 (WEB ONLY)  2013

    J-GLOBAL

  • 光蓄積共振器を用いたレーザーコンプトン散乱X線源の開発

    坂上和之, 鷲尾方一, 荒木栄, ALEXANDER Aryshev, 浦川順治, 照沼信浩, 福田将史, 三好敏喜

    日本加速器学会年会(Web)   10th   MOOT05 (WEB ONLY)  2013

    J-GLOBAL

  • 極短バンチ計測用2Cell型RF‐Deflectorに関する研究

    高橋猛之進, 西村祐一, 西山将大, 坂上和之, 鷲尾方一, 高富俊和, 浦川順治

    日本加速器学会年会(Web)   10th   SAP082 (WEB ONLY)  2013

    J-GLOBAL

  • マイケルソン干渉計と検波器を用いたコヒーレント遷移放射光FT‐THz分光法の開発

    立花充章, 熊木雅史, 坂上和之, 鷲尾方一, 黒田隆之助, 平義隆, 豊川弘之, 山田家和勝

    日本加速器学会年会(Web)   10th   SUP025 (WEB ONLY)  2013

    J-GLOBAL

  • KEK小型電子加速器(LUCX)の現状報告(6)

    福田将史, 荒木栄, ARYSHEV Alexander, 浦川順治, 坂上和之, 照沼信浩, 本田洋介, 鷲尾方一

    日本加速器学会年会(Web)   10th   SAP114 (WEB ONLY)  2013

    J-GLOBAL

  • 27aBC-5 Development of a CO_2 laser storing cavity for a laser-Compton X-ray source

    Ando Kohei, Takeichi Naoto, Sakaue Kazuyuki, Endo Akira, Washio Masakazu

    Meeting Abstracts of the Physical Society of Japan   68 ( 0 ) 157 - 157  2013

    CiNii

  • 26aBA-7 Study on 2 cell RF-deflector cavity for ultra-short electron bunch measurement

    西村 祐一, 高橋 猛之進, 坂上 和之, 鷲尾 方一, 高富 俊和, 浦川 順治

    Meeting Abstracts of the Physical Society of Japan   68 ( 0 ) 141 - 141  2013

    CiNii

  • 29aRC-3 Gamma ray generation by laser Compton scattering for polarized positron source

    Tanaka R, Takahashi T, Terunuma N, Funahashi Y, Honda Y, Yoshitama H, Washio M, Akagi T, Araki S, Urakawa J, Omori T, Okugi T, Kuriki M, Sakaue K, Shimizu H

    Meeting Abstracts of the Physical Society of Japan   68 ( 0 ) 39 - 39  2013

    CiNii

  • 29aRC-4 Instalation of the digital control system in the photon beam generating experiment using by laser-Compton scattering

    Yoshitama Hitoshi, Takahashi Tohru, Tanaka Ryuta, Terunuma Nobuhiro, Funahashi Yoshisato, Honda Yosuke, Washio Masakazu, Akagi Tomoya, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki, Shimizu Hirotaka

    Meeting Abstracts of the Physical Society of Japan   68 ( 0 ) 39 - 39  2013

    CiNii

  • 27aBC-2 Development of Compact X-ray Source with a Pulsed Laser Cavity in LUCX (12)

    Fukuda Masafumi, Araki Sakae, Aryshev Alexander, Urakawa Junji, Sakaue Kazuyuki, Terunuma Nobuhiro, Honda Yosuke, Washio Masakazu

    Meeting Abstracts of the Physical Society of Japan   68 ( 0 ) 156 - 156  2013

    CiNii

  • 27aBC-3 Development of Compact X-ray Source with a Pulsed Laser Cavity in LUCX (13)

    Sakaue Kazuyuki, Araki Sakae, Aryshev Alexander, Urakawa Junji, Terunuma Nobuhiro, Fukuda Masafumi, Honda Yosuke, Washio Masakazu

    Meeting Abstracts of the Physical Society of Japan   68 ( 0 ) 156 - 156  2013

    CiNii

  • Study on two-cell rf-deflector cavity for ultra-short electron bunch measurement

    Y. Nishimura, T. Takahashi, K. Sakaue, M. Washio, T. Takatomi, J. Urakawa

    IEEE Nuclear Science Symposium Conference Record    2013

     View Summary

    We have been developing an S-band Cs-Te photocathode rf electron gun system for various application researches such as pulse radiolysis experiments and laser Compton scattering experiments at Waseda University. These researches demande for high quality and well controlled electron beam. In order to measure the ultra-short electron bunch, we decided to use rf-deflector cavity, which can convert the longitudinal distribution to the transverse. With this technique, the longitudinal bunch profile can be obtained as the transverse profile on the screen monitor. We used the 3D electromagnetic field simulation codes HFSS for designing rf-deflector cavity and GPT for beam tracking. The cavity has two-cell structures operating on π-mode, standing wave, dipole(TM120)mode at 2856 MHz. We have confirmed on HFSS that two-cell rf-deflector cavity can produce 660 G magnetic field per cell on beam line with 750 kW input rf-power. This field strength is equivalent with our target, which is 100 fs bunch length measurement at 4.3 MeV. In this paper, we will present the cavity structure design, and the measurement results of manufactured cavity. © 2013 IEEE.

    DOI

  • Evaluation of sensitivity for positive tone non-chemically and chemically amplified resists using ionized radiation: EUV, X-ray, electron and ion induced reactions

    Akihiro Oshima, Tomoko Gowa Oyama, Masakazu Washio, Seiichi Tagawa

    ADVANCES IN RESIST MATERIALS AND PROCESSING TECHNOLOGY XXX   8682  2013

     View Summary

    The different exposure sources induce a different energy deposition in resist materials. Linear energy transfer (LET) effect for resist sensitivity is very important issue from the viewpoint of radiation induced chemical reactions for high-volume nanofabrication. The sensitivities of positive tone non-chemically (non-CA, ZEP) and chemically amplified (CA, UV-3) resist materials are evaluated using various ionized radiation such as EUV, soft X-rays, EB and various ion beams. Since the notations of sensitivity of resist vary with exposure sources, in order to evaluate systematically, the resist sensitivity were estimated in terms of absorbed dose in resist materials. Highly-monochromated EUV and soft X-rays (6.7 nm - 3.1 nm) from the BL27SU of the SPring-8, high energy ion beams (C6+, Ne10+, Mg12+, Si14+, Ar18+, Kr36+ and Xe54+) with 6 MeV/u from MEXP of HIMAC, EB from low energy EB accelerator (Hamamatsu Photonics, EB-engine(R), 100 kV) and EB lithography system (30 keV and 75keV) were used for the exposure. For non-CA and CA resist materials, it was found that LET effects for sensitivity would be hardly observed except for heavier ion beams. Especially, in the case of the high energy ion beam less than Si14+ with 6 MeV/u, it is suggested that the radiation induced chemical reaction would be equivalent to EUV, soft X-ray and EB exposure. Hence, it indicates that the resist sensitivity could be systematically evaluated by absorbed dose in resist materials.

    DOI

  • Prediction of Resist Sensitivity for 13.5 nm EUV and 6.x nm EUV extension from Sensitivity for EBL

    Tomoko G. Oyama, Akihiro Oshima, Dang Tuan Nguyen, Satoshi Enomoto, Masakazu Washio, Seiichi Tagawa

    EXTREME ULTRAVIOLET (EUV) LITHOGRAPHY IV   8679  2013

     View Summary

    Extreme ultraviolet lithography (EUVL) at 13.5 nm will soon be applied in high-volume manufacturing of semiconductors, as a replacement to the ArF excimer laser immersion lithography. Recently, the potential application of exposure wavelengths of 6.x nm (particularly 6.6-6.8 nm) has been discussed as EUVL extension. The 6.x nm exposure source is currently under development, therefore screening of resists with conventional exposure tools will accelerate the selection or novel development of high sensitivity resists for 6.x nm EUVL. In the present study, the sensitivities of a chemically amplified (CA) resist (OEBR-CAP112) and non-CA resists (ZEP520A and poly(methyl methacrylate)) were evaluated with 30 keV and 75 keV electron beam lithography (EBL) tools. In terms of radiation chemistry, the obtained dose/sensitivities (mu C cm(-2)) were converted into the absorbed doses (Gray; Gy = J kg(-1)). If EB-and EUV-induced chemical reactions are the same, the required absorbed doses for EB and EUV would be similar values. The sensitivities for EUV/soft X-rays including 6.x nm were predicted assuming the required absorbed doses in a resist would show similar values for both EB and EUV. We investigated precise sensitivities of the resists for EUV/soft X-rays including 6.7 nm using highly-monochromated synchrotron radiation. For both CA and non-CA resists, the predicted and experimentally obtained sensitivities agreed well with each other. These results suggested that almost the same chemical reactions are induced in resists for both EUVL and EBL. Hence, it was found that we can predict the resist sensitivities for EUV/soft X-rays at any exposure wavelength from the exposure results for EBL.

    DOI

  • Development of a three dimensional four mirror optical cavity for laser-Compton scattering

    T. Akagi, S. Araki, Y. Funahashi, Y. Honda, H. Kataoka, T. Kon, S. Miyoshi, T. Okugi, T. Omori, K. Sakaue, H. Shimizu, T. Takahashi, R. Tanaka, N. Terunuma, J. Urakawa, M. Washio, H. Yoshitama

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   724   63 - 71  2013

     View Summary

    This paper describes a design and performance of a three-dimensional 4-mirror optical cavity for development of intense photon sources by laser-Compton scattering. We achieved the finesse of 4000 and average power of 2.6 kW in the cavity with the vertical laser beam spot size of 13±1μm in σ at the laser-electron interaction point. As a result, we observed 124±1 photons with average energy of 24 MeV per beam crossing, which corresponds to the generation of 2.7×108 photons per second. © 2013 Elsevier B.V.

    DOI

  • Space charges induced in polymers by electron beam irradiation and their decay profiles

    Naoto Tomite, Yukitaka Arai, Yoshimichi Ohki, Hirotaka Nakmura, Toru Hinata, Masakazu Washio

    Proceedings of IEEE International Conference on Solid Dielectrics, ICSD     736 - 739  2013

     View Summary

    Electrons were irradiated to low-density polyethylene (LDPE), polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and syndiotactic polystyrene (SPS). Many electrons were back scattered and large numbers of electrons and holes were generated in the film by ionization. Since the amount of negative charge observed under short-circuit after the irradiation is significantly smaller than the electron fluence, most electrons and holes generated by the irradiation were either recombined or transported to the electrodes. The amount of negative charge gradually decreases monotonically, showing the order of the decay speed, PI &gt
    LDPE &gt
    PET &gt
    SPS &gt
    PEN. The conductivity also shows the same order. When a dc voltage is applied to the sample, in which electrons and holes were generated abundantly by ionization, the electric field is enhanced significantly at the two electrodes due to the presence of positive charge near the cathode and negative charge near the anode. © 2013 IEEE.

    DOI

  • Study on Two-Cell RF-Deflector Cavity for Ultra-Short Electron Bunch Measurement

    Y. Nishimura, T. Takahashi, K. Sakaue, M. Washio, T. Takatomi, J. Urakawa

    2013 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (NSS/MIC)     2753 - 2755  2013

     View Summary

    We have been developing an S-band Cs-Te photocathode rf electron gun system for various application researches such as pulse radiolysis experiments and laser Compton scattering experiments at Waseda University. These researches demande for high quality and well controlled electron beam. In order to measure the ultra-short electron bunch, we decided to use rf-deflector cavity, which can convert the longitudinal distribution to the transverse. With this technique, the longitudinal bunch profile can be obtained as the transverse profile on the screen monitor. We used the 3D electromagnetic field simulation codes HFSS for designing rf-deflector cavity and GPT for beam tracking. The cavity has two-cell structures operating on pi-mode, standing wave, dipole(TM120)mode at 2856 MHz. We have confirmed on HFSS that two-cell rf-deflector cavity can produce 660 G magnetic field per cell on beam line with 750 kW input rf-power. This field strength is equivalent with our target, which is 100 fs bunch length measurement at 4.3 MeV. In this paper, we will present the cavity structure design, and the measurement results of manufactured cavity.

  • Space Charge Distributions in Polymers Induced by Electron Beam Irradiation and Their Determining Factor

    ARAI Yukitaka, TOMITE Naoto, NAKAMURA Hirotaka, HINATA Toru, WASHIO Masakazu, OHKI Yoshimichi

      2012 ( 93 ) 1 - 6  2012.12

    CiNii

  • Study on electron microbeam generation for MRT based on photo-cathode rf-gun

    Y. Yoshida, K. Sakaue, M. Washio

    IPAC 2012 - International Particle Accelerator Conference 2012     4086 - 4088  2012.12

     View Summary

    We have been developing an MRT (Microbeam Radition Therapy) based on Cs-Te photo-cathode RF-Gun at Waseda University. MRT is proposed to treat tumors by using array of several micro-meter parallel beams. In this therapy, irradiated normal tissue repairs itself, by contrast, even a non-irradiated tumor tissue dies. In the other words, the microbeam enhances the radiation sensitivity difference between normal and tumor issues. Therefore, MRT is considered one of the most useful tumor therapies in the future. We have generated electron microbeam by tungsten collimator slit and analyzed their dose distribution in air and in the PMMA phantom. We have used radiochromic film called GAFCHROMIC dosimetry film type HD-810 to measure them. We have compared these experimental results with Monte Carlo simulation of the dose distribution using the EGS5 code. In this conference, we would like to report the electron microbeam procedure, optimization of irradiation condition and evaluation of microbeam specifications. Coyright © 2012 by IEEE.

  • Development of a high-power coherent THz sources and THz-TDs system on the basis of a compact electron linac

    M. Kumaki, K. Sakaue, M. Washio, R. Kuroda, H. Toyokawa, K. Yamada

    IPAC 2012 - International Particle Accelerator Conference 2012     37 - 39  2012.12

     View Summary

    The high-power terahertz time-domain spectroscopy (THz-TDS) has been developed on the basis of a compact S-band electron linac at AIST, Japan. It is strongly expected for inspection of dangerous materials in the homeland security field. THz radiations are generated in two methods with the ultra-short bunch. One is THz coherent synchrotron radiation (THz-CSR). The other is THz coherent transition radiation (THz-CTR). In the preliminary experiment to obtain the characteristics of THz-CTR, it was observed that the focused THz-CTR had the donut profile in the transverse field due to its initial radial polarization. It was considered to be z-polarization at the focus point. In case of the THz-TDS experiment, THz-CTR was controlled to be linearly polarized with the polarizer and focused to an electro optical (EO) crystal to obtain a THz temporal waveform using EO sampling method. It leads to THz spectrum with Fourier transform. In this paper, we will describe details of our linac and results of the THz-CTR-TDS experiment. Copyright © 2012 by IEEE.

  • RFQ linac commissioning and carbon4+ acceleration for Ag15+ acceleration via directplasma injection scheme

    T. Yamamoto, K. Kondo, M. Sekine, M. Okamura, M. Washio

    IPAC 2012 - International Particle Accelerator Conference 2012     1458 - 1460  2012.12

     View Summary

    Various species of high intensity highly charged state heavy ion beams with smallemittance are required in many fields including particle physics, medical uses, inertialfusion, and simulator of space radiations. Direct Plasma Injection Scheme (DPIS), we havedeveloped for several years, is a unique scheme to provide heavy ion beams to meet theabove requirements. A high-density plasma created by a laser ablation with an initial driftvelocity flies to entrance of a Radio Frequency Quadrupole (RFQ) LINAC; ions will beseparated from plasma via high voltage at the inside of the RFQ LINAC. Then ions arecaptured by the RF buckets and are accelerated remaining high current over 10mA. In thepast, we had accelerated carbon4+, carbon5+, and carbon6+ using a RFQ with partiallymodulated vanes. Due to the un-modulated section of the electrodes, accelerated beams werenot bunched. In 2011, we replaced the vanes with a newly designed one. The designed chargeto mass ratio (q/A) is 1/6 and the output energy is 270 keV/u. The beam commissioning withcarbon 4+ was successfully carried out. In the next step we&#039;ll try to accelerate carbon 2+(q/A=1/6), which is to demonstrate the feasibility of the Ag+15 ion acceleration. Copyright© 2012 by IEEE.

  • Development of an rf electron gun for ultra-short bunch generation

    Y. Koshiba, T. Aoki, K. Sakaue, M. Washio, T. Takatomi, J. Urakawa

    IPAC 2012 - International Particle Accelerator Conference 2012     1536 - 1538  2012.12

     View Summary

    At Waseda University, various researches are done using a photocathode rf electron gunwith a 1.6 cell cavity. Now we are developing a new rf cavity specialized for producing anultra-short electron bunch, with the collaboration of High Energy Accelerator ResearchOrganization (KEK) [1]. We have used SUPERFISH for designing the new rf cavity and PARMELAfor beam tracking. The new rf cavity has an extra cell following the 1.6 cell. The extracell can chirp the energy of electron bunch so we call it ECC (Energy Chirping Cell). ECCchirp the energy because we shortened the length of iris just before the ECC and also thelength of ECC itself. Moreover, electric field in ECC is made to be stronger than others.We have confirmed on PARMELA that ECC-rf-gun can generate an 100pC electron bunch less than100fsec with the energy of 4.5MeV at about 2.5m away from the cathode. Such an ultra-shortelectron bunch enables us to generate a coherent terahertz light using ultra-short electronbunch by synchrotron radiation or transition radiation. In this report, we would like tointroduce the detail of the design of this new ECC-rf-gun, the present progresses andfuture prospects. Copyright © 2012 by IEEE.

  • Gamma-rays generationwith 3d 4-mirror cavity for ilc polarized positron source

    T. Akagi, M. Kuriki, S. Miyoshi, T. Takahashi, R. Tanaka, H. Yoshitama, S. Araki, Y. Funahashi, Y. Honda, T. Okugi, T. Omori, H. Shimizu, N. Terunuma, J. Urakawa, K. Sakaue, M. Washio, H. Kataoka, T. Kon

    IPAC 2012 - International Particle Accelerator Conference 2012     2645 - 2647  2012.12

     View Summary

    We are developing a ILC polarized positron source based on the laser-Comptonscattering. We have already performed a photon generation experiment at the KEK-ATF using aFabry-Perot type 2-mirror laser pulse stacking cavity [1]. The laser pulses are accumulatedand their power was enhanced in the Fabry-Perot cavity. In order further improveperformance of the laser power enhancement, a new three dimensional 4-mirror cavity isdesigned. In this article, we report status of the photon generation experiment. Copyright© 2012 by IEEE.

  • Refraction contrast imaging via laser-compton X-ray using optical storage cavity

    K. Sakaue, T. Aoki, M. Washio, M. Fukuda, Y. Honda, N. Terunuma, J. Urakawa

    IPAC 2012 - International Particle Accelerator Conference 2012     2146 - 2148  2012.12

     View Summary

    We have been developing a pulsed-laser storage technique in a super-cavity for acompact x-ray sources. The pulsed-laser super-cavity enables to make high peak power andsmall waist laser at the collision point with the electron beam. Recently, using 357 MHzmode-locked Nd:VAN laser pulses which stacked in a super-cavity scattered off a multi-bunchelectron beam, we obtained a multi-pulse xrays through the laser-Compton scattering. Then,we performed a X-ray imaging via laser-Compton X-ray. The images have edge enhancement byrefraction contrast because the X-ray source spot size was small enough. This is one of theevidences that laser-Compton X-ray is high quality. Our laser-Compton experimental setup,the results of Xray imaging and future prospective will be presented at the conference.Copyright © 2012 by IEEE.

  • KEKにおけるレーザーコンプトン散乱を用いた小型X線源の開発の現状とアップグレード計画

    福田将史, ARYSHEV Alexander, 荒木栄, 本田洋介, 坂上和之, 照沼信浩, 浦川順治, 鷲尾方一

    加速器   9 ( 3 ) 156 - 164  2012.10

    J-GLOBAL

  • 塩素系電子線レジストの初期過程の解明に関するパルスラジオリシス

    坂本瑞樹, 保坂勇志, 川内洋平, 坂上和之, 大島明博, 大山(五輪)智子, 田川精一, 鷲尾方一

    放射線化学討論会講演要旨集   55th   83 - 84  2012.09

    J-GLOBAL

  • Fabrication of nano space controlled materials using high‐energy heavy ion irradiation

    鷲尾方一, 濱義昌, 坂上和之, 工藤久明, 岡壽崇, 大島明博, 村上健

    NIRS-M (National Inst. of Radiological Sciences)   ( 251 ) 205 - 206  2012.08

    J-GLOBAL

  • フォトカソードRF‐Gunを用いた電子線Microbeam生成

    吉田靖史, 坂上和之, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   49th   108  2012.06

    J-GLOBAL

  • PCFを用いたSC光をプローブとするパルスラジオリシスシステムの最適化

    坂本瑞樹, 保坂勇志, 川内洋平, 坂上和之, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   49th   9  2012.06

    J-GLOBAL

  • 極短バンチ生成用高周波電子銃の開発

    小柴裕也, 青木達朗, 坂上和之, 高富俊和, 浦川順治, 鷲尾方一

    日本物理学会講演概要集   67 ( 1 ) 157  2012.03

    J-GLOBAL

  • 27pGB-7 Development of High-Power THz-Wave Generation and a Spectroscopy System on the Basis of S-band Linac

    Kumaki Masafumi, Kuroda Ryunosuke, Yamaguchi Eriko, Toyokawa Hiroyuki, Sakaue Kazuyuki, Kawauchi Yohei, Yamada Kawakatsu, Washio Masakazu

    Meeting Abstracts of the Physical Society of Japan   67 ( 0 ) 162 - 162  2012

    CiNii

  • 27aGB-10 Study on electron microbeam generation by photocathode RF-Gun for MRT

    Yoshida Yasufumi, Sakaue Kazuyuki, Washio Masakazu

    Meeting Abstracts of the Physical Society of Japan   67 ( 0 ) 157 - 157  2012

    CiNii

  • 27aGB-11 Development of a pulse radiolysis system with a supercontinuum light at Waseda University

    Kawauchi Yohei, Washio Masakazu, Hosaka Yuji, Betto Ryosuke, Ogata Koichi, Sakamoto Mizuki, Sakaue Kazuyuki, Kuroda Ryunosuke, Kashiwagi Shigeru, Ushida Kiminori

    Meeting Abstracts of the Physical Society of Japan   67 ( 0 ) 157 - 157  2012

    CiNii

  • 26pFA-12 Development of the 4-mirror cavity for ILC polarized positron source : Design and installation

    Akagi Tomoya, Shimizu Hirotaka, Takahashi Tohru, Tanaka Ryuta, Terunuma Nobuhiro, Funahashi Yoshisato, Honda Yosuke, Yoshitama Hitoshi, Washio Masakazu, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kataoka Hiromi, Kuriki Masao, Kon Tadashi, Sakaue Kazuyuki

    Meeting Abstracts of the Physical Society of Japan   67 ( 0 )  2012

    CiNii

  • 26pFA-13 Development of the 4-mirror cavity for ILC polarized positron source : Control technique of keeping cavity resonance

    Tanaka R, Sakaue K, Shimizu H, Takahashi T, Terunuma N, Funahashi Y, Honda Y, Yoshitama H, Washio M, Akagi T, Araki S, Urakawa J, Omori T, Okugi T, Kataoka H, Kuriki M, Kon T

    Meeting Abstracts of the Physical Society of Japan   67 ( 0 ) 34 - 34  2012

    CiNii

  • 26pFA-14 Development of the 4-mirror cavity for ILC polarized positron source : Multi-bunch gamma-ray detection

    Kataoka Hiromi, Shimizu Hirotaka, Takahashi Tohru, Tanaka Ryuta, Terunuma Nobuhiro, Funahashi Yoshisato, Honda Yosuke, Yoshitama Hitoshi, Washio Masakazu, Akagi Tomoya, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Kon Tadashi, Sakaue Kazuyuki

    Meeting Abstracts of the Physical Society of Japan   67 ( 0 ) 35 - 35  2012

    CiNii

  • 25aGB-5 Development of a Compact X-ray Source with a Pulsed1 Laser Super-Cavity in LUCX (11)

    Sakaue K, Aoki T, Araki S, Urakawa J, Sasao N, Terunuma N, Fukuda M, Honda Y, Washio M

    Meeting Abstracts of the Physical Society of Japan   67 ( 0 ) 148 - 148  2012

    CiNii

  • 14pSH-5 Development of the optical resonant cavity for ILC polarized positron source

    Tanaka.R, Takahashi T, Terunuma N, Funahashi Y, Honda Y, Yoshitama H, Washio M, Akagi.T, Araki S, Urakawa J, Omori T, Okugi T, Kuriki M, Sakaue K, Shimizu H

    Meeting Abstracts of the Physical Society of Japan   67 ( 0 ) 28 - 28  2012

    CiNii

  • 14pSH-6 Development of digital feedback system for next-generation small-size high-intensity photon beam source

    Yoshitama Hitoshi, Takahashi Tohru, Tanaka Ryuta, Terunuma Nobuhiro, Funahashi Yoshisato, Honda Yosuke, Washio Masakazu, Akagi Tomoya, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki, Shimizu Hirotaka

    Meeting Abstracts of the Physical Society of Japan   67 ( 0 ) 28 - 28  2012

    CiNii

  • Evaluation of PEFC Membrane based on Cross-linked PTFE by EB Grafting: Effect of Thickness for FC Performance

    S. Hiraiwa, T. Yoshikawa, A. Oshima, M. Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   25 ( 4 ) 481 - 485  2012

     View Summary

    The performance of a polymer electrolyte fuel cell (PEFC) was affected by the thickness of the thin proton exchange membrane (PEM). The PEMs with the different thickness were prepared by radiation induced grafting of styrene into the radiation-cross-linked polytetrafluoroethylene (RX-PTFE) membrane prepared from PTFE dispersion, and then sulfonated. The wet thicknesses of the obtained thin PEMs were lower than 25 mu m. A PEM based on a 50 mu m PTFE film, with the wet thickness of 73 mu m, was also prepared under the same procedure for the comparison. The obtained PEMs were characterized in term of gas cross-over. The surface of platinum / carbon electrodes was coated with Nafion (R) dispersion, and then membrane electrode assembles (MEAs) were prepared by the hot-pressing. The polarization curves and electrochemical impedances of the thin PEMs in a single fuel cell were analyzed. As a result, the cell performance of the MEA based on thinner PEM tended to give higher power density and current density. On the other hand, the performance of the thinnest PEM (13 mu m) decreased, and the MEA based on the thinner PEM gave the lower open circuit voltage (OCV) due to the higher gas cross-over. Thus, the thin PEM based on RX-PTFE had shown a high performance at the suitable thickness.

    DOI

  • First Refraction Contrast Imaging via Laser-Compton Scattering X-ray at KEK

    Kazuyuki Sakaue, Tatsuro Aoki, Masakazu Washio, Sakae Araki, Masafumi Fukuda, Nobuhiro Terunuma, Junji Urakawa

    INTERNATIONAL WORKSHOP ON X-RAY AND NEUTRON PHASE IMAGING WITH GRATINGS   1466   272 - 277  2012

     View Summary

    Laser-Compton Scattering (LCS) is one of the most feasible techniques for high quality, high brightness, and compact X-ray source. High energy electron beam produced by accelerators scatters off the laser photon at a small spot. As a laser target, we have been developing a pulsed-laser storage cavity for increasing an X-ray flux. The X-ray flux was still inadequate that was 2.1x10(5)/sec, however, we performed first refraction contrast imaging in order to evaluate the quality of LCS X-ray. Edge enhanced contrast imaging was achieved by changing the distance from sample to detector. The edge enhancement indicates that the LCS X-ray has small source size, i.e. high brightness. We believe that the result has demonstrated good feasibility of linac-based high brightness X-ray sources via laser-electron Compton scatterings.

    DOI

  • Design of a chirping cell attached rf gun for ultra-short electron bunch generation

    K. Sakaue, K. Tamai, M. Washio, J. Urakawa

    IPAC 2011 - 2nd International Particle Accelerator Conference     1129 - 1131  2011.12

     View Summary

    We have been developing an S-band photocathode rf electron gun at Waseda university. Our rf-gun cavity was firstly designed by BNL and then, modified by our group. In this paper, we will introduce a newly designed rf-gun cavity with energy chirping cell. To generate an energy chirped electron bunch, we attached extra-cell for 1.6cell rf-gun cavity. Cavity design was done by Superfish and particle tracking by PARMELA. By optimizing the chirping cell, we observed linear chirped electron bunch. The front electron have lower energy than rear. Then transporting about 2m, the bunch can be compressed down to 200fsec electron bunch with the charge of 160pC. This ultra-short bunch will be able to use for generating CSR THz radiation, pumping some material to be studied by pulse radiolysis method, and so on. In this conference, the design of chirping cell attached rf-gun, the results of tracking simulation and plan of manufacturing will be presented. Copyright © 2011 by IPAC&#039;11/EPS-AG.

  • Study on energy compensation by rf amplitude modulation for high intense electron beam generated by a photocathode rf-gun

    Y. Yokoyama, T. Aoki, K. Sakaue, T. Suzuki, T. Yamamoto, M. Washio, J. Urakawa, N. Terunuma, H. Hayano, S. Kashiwagi, R. Kuroda

    IPAC 2011 - 2nd International Particle Accelerator Conference     1132 - 1134  2011.12

     View Summary

    At Waseda University, we have been studying a high quality electron beam generation and its application experiments with a Cs-Te photocathode RF-Gun. To generate more intense and stable electron beam, we have been developing the cathode irradiating UV laser which consists of optical fiber amplifier and LD pumped amplifier. As the result, more than 100 multi-bunch electron beam with 1nC each bunch charge was obtained. However, it has to be considered that the accelerating voltage will decrease because of the beam loading effect. So we have studied the RF amplitude modulation technique to compensate the beam energy difference. The energy difference will caused by transient accelerating voltage in RF-Gun cavity and beam loading effect. As the result of this compensation method, the energy difference has been compensated to 1%p-p, while 5%p-p without compensation. Copyright © 2011 by IPAC&#039;11/EPS-AG.

  • Development of the pulse radiolysis system with a supercontinuum radiation using photonic crystal fiber

    K. Ogata, Y. Kawauchi, K. Sakaue, T. Suzuki, Y. Hosaka, R. Betto, M. Washio, S. Kashiwagi, R. Kuroda

    IPAC 2011 - 2nd International Particle Accelerator Conference     3645 - 3647  2011.12

     View Summary

    In usage of radiation, it is important to study the process of chemical effects of ionizing radiation in a material. Pulse radiolysis is a method to trace these rapid initial chemical reactions by ionizing radiation. As a pump beam, we are using about 4 MeV electron beam. In nanosecond timescale pulse radiolysis, it is required the stable probe light of a broad spectra. And especially in picosecond timescale pulse radiolysis, probe light should have short pulse width to use stroboscopic method. Therefore, in order to develop a unified timescale experimental system, we developed Supercontinuum (SC) light as a probe light, which is generated by nonlinear optical process of short pulse IR laser in photonic crystal fiber (PCF). To apply SC light as a probe light of pulse radiolysis, we measured its properties. We tried to measure the absorption spectra of hydrated electron by SC light. Then we successfully observed good signal-noise ratio data both in nanosecond and in picosecond experiment with the same system. In a further attempt, we succeeded to improve stability of SC light. Copyright © 2011 by IPAC&#039;11/EPS-AG.

  • Development of an S-band multi-cell accelerating cavity for rf gun and booster linac

    T. Aoki, K. Sakaue, M. Washio, A. Deshpande, J. Urakawa, M. Fukuda, N. Kudo, N. Terunuma, T. Takatomi

    IPAC 2011 - 2nd International Particle Accelerator Conference     110 - 112  2011.12

     View Summary

    We have been developing a photocathode rf gun. The rf gun with multi cell can produce a high energy electron beam, so it may be used for numerous applications such as medicine and industry. At the Laser Undulator Compact X-ray source facility, called LUCX, we have developed a compact X-ray source based on inverse Compton scattering [1]. An S-band 3.5 cell rf electron gun which is 20 cm long can produce a high quality electron beam with energy of 8.7 MeV. According to the simulation, the emittance of 3.5 cell rf gun is as low as that of 1.6 cell rf gun. The electromagnetic design has been performed by the code SUPERFISH, and the particle tracing by PARMELA. The new rf gun is already installed and produced a high quality electron beam with energy of 8.7 MeV. As a consequence of the substantial efforts of developing rf cavity, we decide to make a compact RF accelerating structure with more cell for achieving a smaller system. The measurement results of using the 3.5 cell rf gun, the design of 12 cell booster cavity, and current status of 12 cell cavity manufacturing will be presented at the conference. Copyright © 2011 by IPAC&#039;11/EPS-AG.

  • Generation of long bunch train using RF gun

    Abhay Deshpande, Sakae Araki, Masafumi Fukuda, Kazuyuki Sakaue, Nobuhiro Terunuma, Junji Urakawa, Masakazu Washio

    Proceedings - 25th Linear Accelerator Conference, LINAC 2010     992 - 994  2011.12

     View Summary

    At Laser Undulator Compact X-ray Source (LUCX) facility at KEK, we have developed a RF gun with increased mode separation. Using this RF gun we have successfully generated a bunch train of 300 bunches per train with 160 nC total charge and with peak to peak energy difference less than 0.85% at 5.2 MeV. We plan to generate and accelerate 8000 bunches per train with 0.5 nC per bunch. These bunches will then collide in the collision chamber with laser pulses to produce soft x-ray. After successful results from above work, we take next step and are now designing and fabricating a new 3.5 cell RF gun and a high gradient standing wave linac to achieve 50 MeV beam with 8000-bunches per train. This compact source will be used for future research. This paper details achieved results with existing gun for generation of long bunch train and lists out proposed activity.

  • Fabrication of nano space controlled materials using high‐energy heavy ion irradiation

    鷲尾方一, 濱義昌, 坂上和之, 工藤久明, 岡壽崇, 大島明博, 村上健

    NIRS-M (National Inst. of Radiological Sciences)   ( 244 ) 195 - 196  2011.11

    J-GLOBAL

  • 早稲田大学におけるフォトカソードRF電子銃を用いた大強度電子ビーム源の開発

    横山悠久, 浦川順冶, 柏木茂, 川内洋平, 黒田隆之助, 坂上和之, 鈴木達也, 照沼信浩, 早野仁司, 山本隆之, 鷲尾方一

    放射線化学討論会講演要旨集   54th   113 - 114  2011.09

    J-GLOBAL

  • パルスラジオリシス法による塩素系電子線レジストの反応機構の研究

    保坂勇志, 別當良介, 小方宏一, 大山(五輪)智子, 坂上和之, 榎本一之, 大島明博, 鷲尾方一, 田川精一

    放射線化学討論会講演要旨集   54th   115 - 116  2011.09

    J-GLOBAL

  • 早稲田大学におけるナノ秒・ピコ秒分解能パルスラジオリシスシステムの現状と評価

    別當良介, 保坂勇志, 川内洋平, 小方宏一, 坂上和之, 鷲尾方一, 黒田隆之助, 柏木茂, 丑田公規

    放射線化学討論会講演要旨集   54th   117 - 118  2011.09

    J-GLOBAL

  • スーパーコンティニウム光をプローブとするパルスラジオリシスに関する研究

    川内洋平, 保坂勇志, 別當良介, 小方宏一, 坂上和之, 鷲尾方一, 黒田隆之助, 柏木茂, 丑田公規

    アイソトープ・放射線研究発表会要旨集   48th   97  2011.06

    J-GLOBAL

  • S‐band Linacを用いた高強度コヒーレントTHz波による接着剤の分光測定

    熊木雅史, 坂上和之, 川内洋平, 鷲尾方一, 黒田隆之助, 山口映理子, 豊川弘之, 山田家和勝

    アイソトープ・放射線研究発表会要旨集   48th   30  2011.06

    J-GLOBAL

  • フォトカソードRF電子銃のMRTへの利用の検討

    山本隆之, 鈴木達也, 坂上和之, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   48th   29  2011.06

    J-GLOBAL

  • Changes to the chemical structure of isotactic-polypropylene induced by ion-beam irradiation

    T. Oka, A. Oshima, R. Motohashi, N. Seto, Y. Watanabe, R. Kobayashi, K. Saito, H. Kudo, T. Murakami, M. Washio, Y. Hama

    RADIATION PHYSICS AND CHEMISTRY   80 ( 2 ) 278 - 280  2011.02

     View Summary

    The chemical structures of various ion-beam irradiated isotactic-polypropylene samples were studied. Results of micro-Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy suggest not only the linear energy transfer, but also the fluence is effective in local transformation of the isotactic-polypropylene. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI

  • The effect of water uptake gradient in membrane electrode assembly on fuel cell performance

    H. Fujita, F. Shiraki, Y. Oshima, T. Tatsumi, T. Yoshikawa, T. Sasaki, A. Oshima, M. Washio

    RADIATION PHYSICS AND CHEMISTRY   80 ( 2 ) 201 - 206  2011.02

     View Summary

    Novel proton exchange membranes (PEMs) with functionally gradient ionic sites were fabricated utilizing low energy electron beam (EB) irradiations. The low energy electron beam irradiation to polymer membranes possessed the property of gradient energy deposition in the membrane thickness direction. In the process of EB grafting of styrene onto base films, selective ranges of the gradient energy deposition were used. Micro FT-IR spectra showed that the simulated energy deposition of EB irradiation to base polymer membranes in the thickness direction corresponded to the amount of styrene grafted onto EB-irradiated films. After sulfonation, a functionally gradient ionic site PEM (gradient-PEM) was prepared, corresponding to EB depth-dose profile. The functionally gradients of ionic sites in the gradient-PEM and flat-PEM were evaluated with XPS and SEM-EDX. The results of XPS and SEM-EDX suggest that the prepared gradient-PEM had a gradient sulfonated acid groups. In addition, the polarization performance of MEA based on gradient-PEM was improved in high current density. It was thought that water uptake gradient could have a function to prevent flooding in the MEA during FC operation. Thus, the functionally gradient-PEMs could be a promising solution to manage the water behavior in MEA. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI

  • 25aGAB-11 Development of Pulseradiolysis System with a Supercontinuum Radiation Using a Photocathode RF Electron Gun

    Ogata Koichi, Kawauchi Yohei, Sakaue Kazuyuki, Suzuki Tatsuya, Hosaka Yuji, Betto Ryosuke, Washio Masakazu, Kashiwagi Shigeru, Kuroda Ryunosuke

    Meeting Abstracts of the Physical Society of Japan   66 ( 0 ) 130 - 130  2011

    CiNii

  • 25aGAB-9 Development of a 3.5 cell S-band photocathode RF electron gun

    Aoki Tatsuro, Washio Masakazu, Deshpande Abhay, Urakawa Junji, Kudo Noboru, Sakaue Kazuyuki, Suzuki Tatsuya, Takatomi Toshikazu, Terunuma Nobuhiro, Fukuda Masafumi

    Meeting Abstracts of the Physical Society of Japan   66 ( 0 ) 130 - 130  2011

    CiNii

  • 25aGAB-10 Study of the Multi-bunch Electron Beam Acceleration by Photocathode RF-Gun

    Yokoyama Yukihisa, Yamamoto Takayuki, Washio Masakazu, Aoki Tatsuro, Urakawa Junji, Kashiwagi Shigeru, Kuroda Ryunosuke, Sakaue Kazuyuki, Suzuki Tatsuya, Terunuma Nobuhiro, Hayano Hitoshi

    Meeting Abstracts of the Physical Society of Japan   66 ( 0 ) 130 - 130  2011

    CiNii

  • 28aGF-4 Gamma-rays generation experiment with optical resonant cavity for ILC polarized positron source at the KEK-ATF

    Miyoshi Shuhei, Takahashi Tohru, Terunuma Nobuhiro, Funahashi Yoshisato, Honda Yosuke, Washio Masakazu, Akagi Tomoya, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki, Shimizu Hirotaka

    Meeting Abstracts of the Physical Society of Japan   66 ( 0 ) 32 - 32  2011

    CiNii

  • 28aGF-5 Development of 4-mirror optical cavity for high intensity polarized photons

    Akagi Tomoya, Shimizu Hirotaka, Shirota Chisayo, Takahashi Tohru, Tanaka Ryuta, Terunuma Nobuhiro, Funahashi Yoshisato, Honda Yosuke, Misyoshi Shuhei, Yoshitama Hitoshi, Washio Masakazu, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kataoka Hiromi, Kuriki Masao, Kon Tadashi, Sakaue Kazuyuki

    Meeting Abstracts of the Physical Society of Japan   66 ( 0 ) 32 - 32  2011

    CiNii

  • 25pGAB-12 Development of Compact X-ray Source with a Pulsed Laser Cavity in LUCX (9)

    Fukuda Masafumi, Aryshev Alexander, Araki Sakae, Urakawa Junji, Sakaue Kazuyuki, Sasao Noboru, takano Mikio, Terunuma Nobuhiro, Honda Yosuke, Washio Masakazu

    Meeting Abstracts of the Physical Society of Japan   66 ( 0 ) 138 - 138  2011

    CiNii

  • 25pGAB-13 Development of a Compact X-ray Source with a Pulsed-Laser Super-Cavity in LUCX (10)

    Sakaue K, Araki S, Urakawa J, Sasao N, Terunuma N, Fukuda M, Honda Y, Washio M

    Meeting Abstracts of the Physical Society of Japan   66 ( 0 )  2011

    CiNii

  • 18aSD-6 Gamma-rays generation experiment with 3D 4-mirror cavity for ILC

    Akagi Tomoya, Shimizu Hirotaka, Takahashi Tohru, Tanaka Ryuta, Terunuma Nobuhiro, Funahashi Yoshisato, Honda Yosuke, Miyoshi Shuhei, Yoshitama Hitoshi, Washio Masakazu, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kataoka Hiromi, Kuriki Masao, Kon Tadashi, Sakaue Kazuyuki

    Meeting Abstracts of the Physical Society of Japan   66 ( 0 ) 23 - 23  2011

    CiNii

  • 18aSD-7 Realization of feedback using characteristics of circularly-polarized accumulation in 3-dimensional 4 mirrors optical resonant cavity

    Tanaka R, Sakaue K, Shimizu H, Takahashi T, Terunuma N, Funahashi Y, Honda Y, Yoshitama H, Washio M, Akagi T, Araki S, Urakawa J, Omori T, Okugi T, Kataoka H, Kuriki M, Kon T

    Meeting Abstracts of the Physical Society of Japan   66 ( 0 ) 23 - 23  2011

    CiNii

  • Extendibility of EUV resists in the exposure wavelength from 13.5 down to 3.1 nm for next-generation lithography

    Tomoko G. Oyama, Tomohiro Takahashi, Akihiro Oshima, Masakazu Washio, Seiichi Tagawa

    ADVANCES IN RESIST MATERIALS AND PROCESSING TECHNOLOGY XXVIII   7972  2011

     View Summary

    The increasing density of semiconductor devices has required the development of high resolution exposure techniques. The miniaturization of feature sizes has been achieved mainly by shortening the exposure wavelength. Extreme ultraviolet (EUV) lithography at 13.5 nm exposure wavelength will be introduced into pilot lines in 2011, and high volume manufacturing is expected to be started in 2013/2014. Furthermore, the possibility of extending EUV lithography down to sub 5 nm has been proposed as next-generation lithography, by reducing the exposure wavelength to 6.x nm. ASML has estimated the throughput of exposure system for 6.x nm EUV lithography is comparable with 13.5 nm lithography, based on the experiments such as reflective multilayer optics. However, the estimation has not included the sensitivities of resist materials, which is one of the most important criteria for the practical lithography systems. Here, the sensitivities of several kinds of typical resists in EUV/soft X-ray wavelength down to 3.1 nm were actually evaluated by experiments. The sensitivities of resist materials were roughly proportional to the absorbed dose calculated by line absorption coefficients of resists. The dependence of the exposure wavelength on EUV resist sensitivity could be theoretically predicted for the next-generation lithography, if sensitivity at a certain EUV wavelength like 13.5 nm is experimentally obtained.

    DOI

  • Nanofabrication of Sulfonated Polystyrene-g-FEP with Silver Ion (Ag+) using Ion Beam Direct Etching and Reduction

    Hidehiro Tsubokura, Akihiro Oshima, Tomoko Gowa Oyama, Hiroki Yamamoto, Takeshi Murakami, Seiichi Tagawa, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   24 ( 5 ) 513 - 516  2011

     View Summary

    Functionalized poly(tetrafluoroethylene-co-hexafluoropropylene (FEP)) was fabricated by electron beam (EB) induced grafting technique and chemical sulfonation treatment. The functionalized FEP (s-FEP) films were immersed in the silver nitrate (AgNO3) solution under ambient condition, to exchange on ionic sites from proton ion-form to Ag+ ion-form, and then the Ag-formed s-FEP polymers were obtained. Ag-formed s-FEP was irradiated with 30 keV Ga+ focused ion beam (FIB) and 6 MeV/u dispersed Ne10+ ion beam (DIB). The irradiated areas were evaluated by a scanning electron microscopy (SEM) with an energy dispersive X-ray spectroscopy (EDX). In both cases of FIB and DIB irradiations, the nano-scale particles were appeared on the surface of irradiated areas. From the results of EDX analysis for the particles, the peaks which were assigned to silver atoms were clearly detected, and peak intensities were higher than un-irradiated one. It is suggested that the Ag+ ions would be reduced by ion beam irradiation and appeared as silver nano-scale particles with pure silver metal and its oxidative chemical compounds.

    DOI

  • Pulse radiolysis with supercontinuum probe generated by PCF

    Y. Hosaka, R. Betto, A. Fujita, K. Sakaue, M. Washio, R. Kuroda, S. Kashiwagi, K. Ushida

    IPAC 2010 - 1st International Particle Accelerator Conference     145 - 147  2010.12

     View Summary

    We have been studying a pump-probe pulse radiolysis as an application of the S-band photo cathode RF-Gun. Pump-probe spectroscopy is well-known method of pulse radiolysis measurement. We had used 5MeV electron beam obtained from the photo cathode RF-Gun as a pump beam, and used the white light emitted from Xe flash lamp or generated by self-phase modulation in the water cell as a probe light. However, the white probe light with high intensity, good stability and broad spectrum is a key issue for pump-probe pulse radiolysis. Supercontinuum light with photonic crystal fiber (PCF) is a new technique of white light generation. Short pulse laser through PCF spreads its spectrum by nonlinear optical effect. Supercontinuum light has very continuous spectrum, and it is studied for various applications recently. For applying supercontinuum light as a probe of pulse radiolysis experiment, we have generated a supercontinuum radiation with 7 picoseconds pulse width IR (1064nm) laser and PCF, and measured its properties. The experimental results of supercontinuum generation and design of a supercontinuum based pulse radiolysis system will be presented.

  • Experimental results of RF gun and generation of multi bunch beam

    Abhay Deshpande, Sakae Araki, Masafumi Fukuda, Nobuhiro Terunuma, Junji Urakawa, Kazuyuki Sakaue, Masakazu Washio

    IPAC 2010 - 1st International Particle Accelerator Conference     4104 - 4106  2010.12

     View Summary

    At Laser Undulator Compact Source (LUCX) at KEK, we designed and made a new RF Gun with high mode separation of 8.6 MHz and high Q value as compared to earlier guns. This paper presents fabrication details, low power measurements and tuning procedures followed in making the gun cavity. We also discuss in detail, experimentation done using this gun and show the measurement results. Currently we produce 100 bunch per train but we plan to go for 300 or more bunch per train operation. This will make possible to have higher charge available for laser-beam collisions to generate high flux soft X-rays by Inverse Compton Scattering at our setup.

  • Status and future plan of the accelerator for laser undulator compact X-ray source (LUCX)

    M. Fukuda, S. Araki, A. Aryshev, Y. Honda, N. Terunuma, J. Urakawa, A. Deshpande, K. Sakaue, M. Washio, N. Sasao

    IPAC 2010 - 1st International Particle Accelerator Conference     2111 - 2113  2010.12

     View Summary

    We have developed a compact X-ray source via inverse Compton scattering between an electron beam and a laser pulse stacked in an optical super-cavity at Laser Undulator Compact X-ray (LUCX) accelerator in KEK. The accelerator consists of a photo-cathode RF-gun and an S-band accelerating tube and now produces the multi-bunch electron beam with 100 bunches, 0.5nC bunch charge and 40MeV beam energy. It is planned to upgrade the RF-gun and the RF system of the accelerator and the super-cavity in order to increase the X-ray yield. The new RF-gun with high mode separation and high Q value and a new klystron for the gun will be installed to provide good compensation with a high-intensity multi-bunch electron beam. A new optical super-cavity consisting of 4 mirrors is also being developed to enhance the stacking power in the cavity and to reduce the laser size at the focal point. The first targets are to produce a multi-bunch electron beam with 3000 bunches, 0.5nC bunch charge and 5MeV beam energy in low energy mode and with 100 bunches, 2nC and 40 MeV in high energy mode to generate X-rays by inverse Compton scattering. In this paper, the status and future plan of the accelerator will be reported.

  • Design of high brightness light source based on laser-compton undulator for EUV lithography mask inspection

    K. Sakaue, M. Washio, A. Endo

    IPAC 2010 - 1st International Particle Accelerator Conference     148 - 150  2010.12

     View Summary

    We will present a design of high brightness light source for EUV lithography mask inspection. The required system parameters are minimum brightness of 2500W/mm2/Sr at 13.5nm/2% bandwidth. Our design consists of superconducting DC RF-gun as a radiator and 10.74nm CO2laser stacked in an optical cavity as a laser undulator. Recent achievements of each component technologies, which is 1.3GHz SC-RF-gun, 10kW average power short pulse CO2laser, and laser storage optical super-cavity, indicate the feasibility of producing required brightness based on laser Compton undulator. Design parameters of high brightness EUV source, the technological gap of the present component technologies and required further developments will be resented at the conference.

  • Multi-bunch electron beam generation based on CS-TE photocathode RF-Gun at Waseda University

    Y. Yokoyama, T. Aoki, K. Sakaue, T. Suzuki, J. Yokose, M. Washio, J. Urakawa, N. Terunuma, H. Hayano, S. Kashiwagi, R. Kuroda

    IPAC 2010 - 1st International Particle Accelerator Conference     4119 - 4121  2010.12

     View Summary

    At Waseda University, we have been studying a high quality electron beam generation and its application experiments with Cs-Te photocathode RF-Gun. We have already succeeded in generating a stable high-charged single-bunch electron beam. To generate more intense electron beam, we designed a multi-bunch electron linac and developed the multi-pulse UV laser which irradiates to the cathode. The target values of the number of electron bunch and bunch charges are 100 bunches/train and 800pC/bunch, respectively. In addition, we adopted the method of the amplitude modulation of the incident RF pulse to the S-band klystron in order to compensate the energy difference in each bunch because of the slow rise time of acceleration voltage in cavity and beam loading effect in the accelerating structure.

  • Photon generation by laser-Compton scattering at the KEK-ATF

    S. Miyoshi, T. Akagi, S. Araki, Y. Funahashi, T. Hirose, Y. Honda, M. Kuriki, X. Li, T. Okugi, T. Omori, G. Pei, K. Sakaue, H. Shimizu, T. Takahashi, N. Terunuma, J. Urakawa, Y. Ushio, M. Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   623 ( 1 ) 576 - 578  2010.11

     View Summary

    We performed a photon generation experiment by laser-Compton scattering at the KEK-ATF,aiming to develop a Compton based polarized positron source for linear colliders. In the experiment, laser pulses with a 357 MHz repetition rate were accumulated and their power was enhanced by up to 250 times in the Fabry-Perot optical resonant cavity. We succeeded in synchronizing the laser pulses and colliding them with the 1.3 GeV electron beam in the ATF ring while maintaining the laser pulse accumulation in the cavity. As a result, we observed 26.0 +/- 0.1 photons per electron-laser pulse crossing, which corresponds to a yield of 10(8) photons in a second. (C) 2010 Elsevier B.V. All rights reserved.

    DOI

  • 重イオン照射による傾斜機能材料の創製

    大島明博, 白木文也, 高澤侑也, 藤田創, 吉川妙子, 巽貴浩, 坪倉英裕, 高橋朋宏, 大山(五輪)智子, 坂上和之, 岡壽崇, 工藤久明, 村上健, 鷲尾方一, 濱義昌

    放射線化学討論会講演要旨集   53rd   9 - 10  2010.09

    J-GLOBAL

  • 早稲田大学加速器システムにおける高品質電子ビーム生成の現状

    青木達朗, 坂上和之, 鈴木達也, 保坂勇志, 別當良介, 横山悠久, 黒田隆之助, 柏木茂, 鷲尾方一

    放射線化学討論会講演要旨集   53rd   143 - 144  2010.09

    J-GLOBAL

  • ピコ秒パルスラジオリシスへの導入に向けたスーパーコンティニウム光生成に関する研究

    別當良介, 保坂勇志, 鈴木達也, 坂上和之, 小方宏一, 川内洋平, 鷲尾方一, 黒田隆之助, 柏木茂, 丑田公規

    放射線化学討論会講演要旨集   53rd   145 - 146  2010.09

    J-GLOBAL

  • フォトカソードRF‐Gunを用いた制動放射線生成試験

    青木達朗, 坂上和之, 鈴木達也, 黒田隆之助, 柏木茂, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   47th   107  2010.06

    J-GLOBAL

  • パルスラジオリシスのためのスーパーコンティニウム光生成に関する研究

    別當良介, 坂上和之, 鈴木達也, 藤田晃弘, 保坂勇志, 鷲尾方一, 柏木茂, 黒田隆之介, 丑田公規

    アイソトープ・放射線研究発表会要旨集   47th   5  2010.06

    J-GLOBAL

  • High‐energy heavy ion irradiation effects on polymer materials―Localization of chemical reaction by different chemical structures―

    鷲尾方一, 濱義昌, 坂上和之, 工藤久明, 岡壽崇, 大島明博, 村上健

    NIRS-M (National Inst. of Radiological Sciences)   ( 234 ) 203 - 204  2010.06

    J-GLOBAL

  • 21pBF-9 Development of multi bunch electron beam accelerator based on Cs-Te photocathode RF-Gun

    Yokose Junichiro, Yokoyama Yukihisa, Washio Masakazu, Aoki Tatsuro, Urakawa Junji, Kashiwagi Shigeru, Kuroda Ryunosuke, Sakaue Kazuyuki, Suzuki Tatsuya, Terunuma Nobuhiro, Hayano Hitoshi

    Meeting Abstracts of the Physical Society of Japan   65 ( 0 ) 140 - 140  2010

    CiNii

  • 21pBF-10 Study of the Energy Compensation of Multi-bunch Electron Beam produced by Photocathode RF-Gun using the ΔA RF Modulation Method

    Yokoyama Yukihisa, Washio Masakazu, Urakawa Junji, Kashiwagi Shigeru, Kuroda Ryunosuke, Sakaue Kazuyuki, Suzuki Tatsuya, Terunuma Nobuhiro, Hayano Hitoshi, Yokose Junichiro

    Meeting Abstracts of the Physical Society of Japan   65 ( 0 ) 140 - 140  2010

    CiNii

  • 22pBE-1 Gamma-rays generation experiment with optical resonant cavity for ILC polarized positron source at the KEK-ATF

    Miyoshi Shuhei, Takahashi Tohru, Terunuma Nobuhiro, Nagata Shuji, Hirose Tachishige, Funahashi Yoshisato, Pei Guoxi, Honda Yosuke, Washio Masakazu, Akagi Tomoya, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki, Shimizu Hirotaka

    Meeting Abstracts of the Physical Society of Japan   65 ( 0 ) 27 - 27  2010

    CiNii

  • 22pBE-2 Development of 4-mirror optical cavity for high intensity polarized photons

    Akagi Tomoya, Terunuma Nobuhiro, Nagata Shuji, Nakamura Shunsuke, Hirose Tachishige, Funahashi Yoshisato, Pei Guoxi, Honda Yosuke, Miyoshi Shuhei, Washio Masakazu, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki, Shimizu Hirotaka, Takahashi Tohru

    Meeting Abstracts of the Physical Society of Japan   65 ( 0 ) 27 - 27  2010

    CiNii

  • 14aSK-9 Gamma-rays generation experiment with optical resonant cavity for ILC polarized positron source at the KEK-ATF

    Miyoshi Shuhei, Takahashi Tohru, Terunuma Nobuhiro, Nagata Shuji, Hirose Tachishige, Funahashi Yoshisato, Honda Yosuke, Washio Masakazu, Akagi Tomoya, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki, Shimizu Hirotaka

    Meeting Abstracts of the Physical Society of Japan   65 ( 0 ) 21 - 21  2010

    CiNii

  • 14aSK-10 Development of 4-mirror optical cavity for high intensity polarized photons

    Akagi Tomoya, Terunuma Nobuhiro, Nagata Shuji, Nakamura Shunsuke, Hirose Tachishige, Funahashi Yoshisato, Honda Yosuke, Miyoshi Shuhei, Washio Masakazu, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki, Shimizu Hirotaka, Takahashi Tohru

    Meeting Abstracts of the Physical Society of Japan   65 ( 0 ) 21 - 21  2010

    CiNii

  • Improvement of an S-band RF gun with a Cs2Te photocathode for the KEK-ATF

    N. Terunuma, A. Murata, M. Fukuda, K. Hirano, Y. Kamiya, T. Kii, M. Kuriki, R. Kuroda, H. Ohgaki, K. Sakaue, M. Takano, T. Takatomi, J. Urakawa, M. Washio, Y. Yamazaki, J. Yang

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   613 ( 1 ) 1 - 8  2010.01

     View Summary

    A laser-driven RF gun with a Cs2Te photocathode, a device modeled after the BNL-IV RF gun, has been in development at KEK since 2002. This gun has been operated as an electron source for the Accelerator Test Facility (ATF) and generates a beam with an operational intensity of up to 3.2 nC per bunch. Based on successful results at the ATF, this gun has been applied several times for new research at universities. From 2002 onwards, successive improvements have been incorporated into newer models of the RF gun. Most recently, in 2008, a new gun incorporating all of the earlier modifications was produced for the ATE Tests have confirmed a significant improvement of the Q-value of the latest model. A typical transverse emittance of 1.3 pi mm mrad has been obtained under the following conditions: solenoid field of 0.18 T, beam intensity of 1.6 nC per bunch, and RF power of 9 MW. This RF gun equipped with the Cs2Te photocathode is being used for the advanced research programs at the ATF. A survey of its performance has recently been completed. (C) 2009 Elsevier B.V. All rights reserved.

    DOI

  • Ion-beam irradiation effects on polyimide-UV-vis and infrared spectroscopic study

    H. Kudo, S. Sudo, T. Oka, Y. Hama, A. Oshima, M. Washio, T. Murakami

    RADIATION PHYSICS AND CHEMISTRY   78 ( 12 ) 1067 - 1070  2009.12

     View Summary

    Ion-beam irradiation effects on polyimide, Kapton (TM), were studied with respect to optical and electronic properties. Stack films of Kapton (TM) (12.5 mu m thick) were irradiated to various ion beams in air or vacuo at room temperature and subjected to ultraviolet-visible (UV-vis) spectroscopy, and change in absorbance and energy gap is discussed. The UV-vis absorption spectrum, which is assigned to the transition of electrons in benzene rings from pi to pi* orbital, upon He(2+) (6MeV/u) irradiation in air, shifted towards longer wavelength direction for all cases, and the shift was more obvious for higher linear energy transfer (LET) ion beams. The energy gap of the transition was estimated, and the H(+) and He(2+) ion beams caused little change in the transition energy gap Eg, while the heavier ions such as C(6+) and Si(14+) caused more significant decrease. This decrease is assumed to the structural changes around benzene rings, and the infrared spectroscopy revealed breakage in imide groups next to benzene ring in the repeating unit of polyimide. (C) 2009 Elsevier Ltd. All rights reserved.

    DOI

  • Development of compact coherent EUV source based on laser Compton scattering

    S. Kashiwagi, R. Kato, G. Isoyama, K. Sakaue, A. Masuda, T. Nomoto, T. Gowa, M. Washio, R. Kuroda, J. Urakawa

    RADIATION PHYSICS AND CHEMISTRY   78 ( 12 ) 1112 - 1115  2009.12

     View Summary

    High-power extreme ultra-violet (EUV) sources are required for next generation semiconductor lithography. We start to develop a compact EUV source in the spectral range 13-14 nm, which is based on a laser Compton scattering between a 7 MeV micro-bucnhed electron beam and a high-intensity CO laser pulse. The electron beam extracted from a DC photocathode gun is micro-bunched using a laser modulation techinque with the Compton wavelength at a harmonic of the seeding laser before the main laser Compton scattering for EUV generation. A considerating scheme for the compact EUV source based on the laser Compton scattering with micro-bunched electron beam and the analytical study of micro-bunch generation are described in this paper. (C) 2009 Elsevier Ltd. All rights reserved.

    DOI

  • APSRC-2008 "The Second Asia-Pacific Symposium on Radiation Chemistry", August 29-September 1, 2008 Preface

    Yosuke Katsumura, Akihiro Oshima, Masakazu Washio

    RADIATION PHYSICS AND CHEMISTRY   78 ( 12 ) 1019 - 1020  2009.12

    Other  

    DOI

  • Observation of pulsed x-ray trains produced by laser-electron Compton scatterings

    Kazuyuki Sakaue, Masakazu Washio, Sakae Araki, Masafumi Fukuda, Yasuo Higashi, Yosuke Honda, Tsunehiko Omori, Takashi Taniguchi, Nobuhiro Terunuma, Junji Urakawa, Noboru Sasao

    REVIEW OF SCIENTIFIC INSTRUMENTS   80 ( 12 )  2009.12

     View Summary

    X-ray generation based on laser-electron Compton scattering is one attractive method to achieve a compact laboratory-sized high-brightness x-ray source. We have designed, built, and tested such a source; it combines a 50 MeV multibunch electron linac with a mode-locked 1064 nm laser stored and amplified in a Fabry-Perot optical cavity. We directly observed trains of pulsed x rays using a microchannel plate detector; the resultant yield was found to be 1.2 x 10(5) Hz in good agreement with prediction. We believe that the result has demonstrated good feasibility of linac-based compact x-ray sources via laser-electron Compton scatterings. (C) 2009 American Institute of Physics. [doi:10.1063/1.3272789]

    DOI

  • Femto-second profile moniitor using pulsed laser storage in an optical cavity

    K. Sakaue, M. Washio, S. Araki, M. Fukuda, Y. Higashi, Y. Honda, T. Taniguchi, N. Terunuma, J. Urakawa, N. Sasao

    FEL 2009 - 31st International Free Electron Laser Conference     297 - 300  2009.12

     View Summary

    We have been developing a pulsed-laser storage technique in a super-cavity for a compact x-ray sources. The pulsed-laser super-cavity enables to make high peak power and small waist laser at the collision point with the electron beam. Recently, using 357MHz mode-locked Nd:VAN laser pulses which stacked in a super-cavity scattered off a multi-bunch electron beam, we obtained a multi-pulse x-rays through the laser-Compton scattering. Detecting an x-ray pulse-by-pulse using high-speed detector makes it possible to measure the 3-dimensional beam size with bunch-by-bunch scanning the laserwire target position and pulse timing. This technique has a feasibility of measuring femto-second bunch length by stacking femto-second pulse in an optical cavity. Design study of femto-second laser-wire monitor and the experimental demonstration using pico-second pulse storage and multi-bunch electron beam will be presented at the conference.

  • Development of a Cs-Te cathode RF gun at waseda university

    Y. Kato, K. Sakaue, T. Suzuki, A. Murata, C. Igarashi, A. Masuda, T. Nomoto, A. Fujita, T. Hirose, Y. Hama, M. Washio, J. Urakawa, T. Takatomi, N. Terunuma, H. Hayano, S. Kashiwagi, R. Kuroda, Y. Kamiya, M. Kuriki

    Proceedings of the 24th Linear Accelerator Conference, LINAC 2008     624 - 626  2009.12

     View Summary

    A photo-cathode RF-Gun is one of the good alternatives for the electron source, because of its high gradient on the electron emitter causing small beam emittance, and tenability of initial beam profile especially for electron bunch length. Therefore, we are operating as a high brigh-tness short pulse electron source. In last year, we have been developing a high quality electron source based on photo-cathode RF-gun which is newly designed RF cavity and has a Cs-Te cathode with high quantum efficiency [1] [2]. Improved RF-Gun cavity has four compact tuners on each half cell and full cell, which can be tuned the resonance frequency to deform the cavity wall. Also removing the Helicoflex seal and tuning holes, reduction of the dark current is expected. According to these improvements, the Q value and shunt impedance of the new RF-Gun cavity increased 20% compared with the previous RF cavity. In addition, the dark current of cavity was reduced and the good electron beam parameters could be achieved compared with pre-vious RF-Gun with a Cu cathode.

  • Demonstration of multi-pulse x-ray generation via laser-compton scattering using pulsed-laser super-cavity

    K. Sakaue, M. Washio, S. Araki, M. Fukuda, Y. Higashi, Y. Honda, T. Taniguchi, T. Terunuma, J. Urakawa, N. Sasao

    Proceedings of the 24th Linear Accelerator Conference, LINAC 2008     545 - 547  2009.12

     View Summary

    A compact and high quality x-ray source is required for various field, such as medical diagnosis, drug manifacturing and biological sciences. Laser-Compton based x-ray source that consist of a compact electron storage ring and a pulsed-laser super-cavity is one of the solutions of a compact x-ray source. Pulsed-laser super-cavity has been developed at Waseda university for a compact high brightness x-ray source. The pulsed-laser super-cavity enables to make high peak power and small waist laser at the collision point with the electron beam. 357MHz mode-locked Nd:VAN laser pulses can be stacked stably in a 420mm long Fabry-Perot cavity with &quot;burst mode&quot;, which means stacking of electron beam synchronized amplified pulses in our R&amp; D. In view of this successful result, we have started an X-ray generation experiment using a super-cavity and a multi-bunch electron beam at KEK-LUCX. Recently, the demonstration experiment between the burst mode pulsedlaser super-cavity and the 100 bunch multi-bunch electron beam is successfully performed. Development of the supercavity and the experimental results of X-ray generationwill be presented at the conference.

  • 早稲田大学におけるフォトカソードRF‐Gunを用いたパルスラジオリシスシステムの進展と今後の計画

    保坂勇志, 坂上和之, 藤田晃宏, 別當良介, 鷲尾方一, 柏木茂, 黒田隆之助, 丑田公規

    放射線化学討論会講演要旨集   52nd   123 - 124  2009.09

    J-GLOBAL

  • 高輝度偏極光源の為の新型レーザー蓄積共振器の開発 I

    三好修平, 赤木智哉, 荒木栄, 浦川順治, 大森恒彦, 奥木敏行, 栗木雅夫, 坂上和之, 清水洋孝, 高橋徹, 照沼信浩, 永田修司, 広瀬立成, 舟橋義聖, PEI Guoxi, 本田洋介, LI XiaoPing, 鷲尾方一

    日本物理学会講演概要集   64 ( 2 ) 19  2009.08

    J-GLOBAL

  • Photon Generation by Laser-Compton Scattering Using an Optical Resonant Cavity at the KEK-ATF Electron Ring

    Hirotaka Shimizu, Sakae Araki, Yoshisato Funahashi, Yosuke Honda, Toshiyuki Okugi, Tsunehiko Omori, Nobuhiro Terunuma, Junji Urakawa, Masao Kuriki, Shuhei Miyoshi, Tohru Takahashi, Yasuaki Ushio, Tachishige Hirose, Kazuyuki Sakaue, Masakazu Washio, Pei Guoxi, Li XiaoPing

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   78 ( 7 )  2009.07

     View Summary

    We studied gamma-ray generation by the laser-Compton scattering using a Fabry-Perot optical resonant cavity at the KEK-ATF electron storage ring. The laser power was enhanced up to 388 W in the optical resonant cavity with an injection power of 7 W in the ATF operation environments. The yield of photons for a crossing of a laser pulse and an electron bunch was 3.3 +/- 0.6, which was consistent with a numerical estimate. In this paper, we report construction, installation and future prospect toward the polarized positron generation for the International Linear Collider.

    DOI

  • 早稲田大学におけるナノ秒パルスラジオリシスシステムの構築と評価

    保坂勇志, 坂上和之, 野本知章, 藤田晃宏, 鷲尾方一, 柏木茂, 黒田隆之助, 丑田公規

    アイソトープ・放射線研究発表会要旨集   46th   20  2009.06

    J-GLOBAL

  • KEK‐ATFにおけるILC偏極陽電子源の為のレーザー共振器を用いた高輝度ガンマ線生成実験 I

    三好修平, 赤木智哉, 荒木栄, 牛尾恭章, 浦川順治, 大森恒彦, 奥木敏行, 栗木雅夫, 坂上和之, 清水洋孝, 高橋徹, 照沼信浩, 広瀬立成, 舟橋義聖, PEI Guoxi, 本田洋介, LI XiaoPing, 鷲尾方一

    日本物理学会講演概要集   64 ( 1 ) 23  2009.03

    J-GLOBAL

  • Design of a mode separated RF photo cathode gun

    Abhay Deshpande, Sakae Araki, Masafumi Fukuda, Kazuyuki Sakaue, Nobuhiro Terunuma, Junji Urakawa, Noboru Sasao, Masakazu Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   600 ( 2 ) 361 - 366  2009.03

     View Summary

    Our group at the Laser Undulator Compact X-ray source facility (LUCX), KEK (High Energy Accelerator Research Organization) is performing experiments to generate X-rays by inverse Compton scattering. The system, to generate the X-rays requires a high intensity beam with low emittance. In this research we propose modifications to the existing system to achieve an acceleration of 200 nC in 100 bunches. Specifically, we seek to demonstrate that a new RF gun with high mode separation and high Q value will achieve a beam of good quality. A new RF power system with a modified power delivery scheme provides a good beam loading compensation with a high-intensity multi-bunch electron beam. The acceleration of 200 nC in 100 bunches with low emittance will help increase the intensity of X-rays by inverse Compton scattering. (C) 2008 Elsevier B.V. All rights reserved.

    DOI

  • 28pZB-9 Present Status of Developing Soft X-ray Source via Multi-pulse Inverse Compton Scattering at Waseda University

    Masuda Akihiko, Shinohara Kunio, Suzuki Tatsuya, Hayano Hitoshi, Fujino Tatsuki, Mitsuda Naoya, Murata Aki, Washio Masakazu, Igarashi Chiaki, Ushida Kiminori, Urakawa Junji, Kashiwagi Shigeru, Kato Yuta, Kuroda Ryunosuke, Gowa Tomoko, Sakaue Kazuyuki

    Meeting Abstracts of the Physical Society of Japan   64 ( 0 )  2009

    CiNii

  • 30aXE-1 Development of a nano-second pulse radiolysis system at Waseda University

    Fujita Akihiro, Sakaue Kazuyuki, Nomoto Tomoaki, Hama Yoshimasa, Hosaka Yuji, Washio Masakazu, Kuroda Ryunosuke, Kashiwagi Shigeru, Ushida Kiminori

    Meeting Abstracts of the Physical Society of Japan   64 ( 0 ) 117 - 117  2009

    CiNii

  • 27aSB-2 Gamma-rays generation experiment with optical cavity For ILC polarized positron source at KEK-ATF

    Akagi Tomoya, Takahashi Tohru, Terunuma Nobuhiro, Hirose Tachishige, Funahashi Yoshisato, Pei Guoxi, Honda Yosuke, Li XiaoPing, Miyoshi Shuhei, Washio Masakazu, Araki Sakae, Ushio Yasuaki, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki, Shimizu Hirotaka

    Meeting Abstracts of the Physical Society of Japan   64 ( 0 ) 24 - 24  2009

    CiNii

  • 27aZB-7 The Study of Beam Physics with Photo Cathode RF-Gun at Waseda University

    Suzuki Tatsuya, Fujino Tatsuki, Murata Aki, Washio Masakazu, Urakawa Junji, Kasiwagi Shigeru, Kato Yuta, Kuroda Ryunosuke, Sakaue Kazuyuki, Takatomi Toshikazu, Terunuma Nobuhiro, Hayano Hitoshi

    Meeting Abstracts of the Physical Society of Japan   64 ( 0 ) 105 - 105  2009

    CiNii

  • 28pZB-4 Development of a Compact X-ray Source with a Pulsed-Laser Super-Cavity in LUCX (7)

    Sakaue K, Muto T, Washio M, Araki S, Urakawa J, Sasao N, Taniguchi T, Terunuma N, Higashi Y, Fukuda M, Honda Y

    Meeting Abstracts of the Physical Society of Japan   64 ( 0 ) 110 - 110  2009

    CiNii

  • 10aSF-2 Development of new type optical resonant cavity for high intensity polarized photons

    Nagata Shuji, Shimizu Hirotaka, Takahashi Tohru, Terunuma Nobuhiro, Hirose Tachishige, Funahashi Yoshisato, Pei Guoxi, Honda Yosuke, Li XiaoPing, Washio Masakazu, Miyoshi Shuhei, Akagi Tomoya, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki

    Meeting Abstracts of the Physical Society of Japan   64 ( 0 ) 20 - 20  2009

    CiNii

  • Development of a Compact X-ray Source and Super-sensitization of Photo Resists for Soft X-ray Imaging

    Tomoko Gowa, Naoyuki Fukutake, Yoshimasa Hama, Kentaro Hizume, Takashi Kashino, Shigeru Kashiwagi, Ryunosuke Kuroda, Akihiko Masuda, Akihiro Oshima, Taku Saito, Kazuyuki Sakaue, Kunio Shinohara, Tomohiro Takahashi, Tatsuya Urakawa, Kiminori Ushida, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   22 ( 3 ) 273 - 278  2009

     View Summary

    A compact soft X-ray source via inverse Compton scattering has been developed at Waseda University. The energies of the generated X-rays are within "water window" region (250 - 500 eV) and development of a soft X-ray microscope is expected which can get the elemental mapping of carbon and/or nitrogen without dehydration. We have studied to develop a high resolution soft X-ray imaging system with photo resists for nanoscale observation. However, the yield of generated X-rays had been too small for the practical use of the soft X-ray microscopy. To enhance the X-ray yield, we have upgraded the generation system and succeeded in increasing the detected photons 10-fold. Total generated photons were estimated to be over 1.5E+5 photons/s. Also, super-sensitization of photo resists has been attempted to reduce the required X-ray amount. By irradiating quasi-monochromatic X-rays in the water window region from synchrotron radiation at BL12 of the SAGA-LS, the sensitivity of a deep-UV photo resist, TDUR-P722 (Tokyo Ohka Kogyo Co., Ltd) was evaluated. After UV light (including 254 nm) exposure up to the sensitivity threshold and baking as PEB process, it was found that the resist becomes more sensitive. This UV "pre-exposure" method reduced the required 400 eV X-ray amount by over 65%.

    DOI

  • Nano-fabrication and Functionalization of Crosslinked PTFE Using Focused Ion Beam

    Yuya Takasawa, Naoyuki Fukutake, Kazumasa Okamoto, Akihiro Oshima, Seiichi Tagawa, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   22 ( 3 ) 341 - 345  2009

     View Summary

    It was demonstrated that the nano / microfabrication and functionalization for crosslinked Polytetrafluoroethylene (RX-PTFE) were carried out using focused ion beam (FIB). The fine pattern of the regularly nano-scale square array holes with 300 nm square size were fabricated by FIB direct etching. The fabricated samples were functionalized by post grafting reaction using trapped free radicals induced by FIB irradiation, and the samples were successively sulfonated. The obtained samples were treated by the mixture solution of KOH/KCI to make potassium form, and observed by FE-SEM with EDX spectroscopy. The signals correspond to potassium atom were detected at the holes in fabricated area of RX-PTFE. On the other hand, the signals of potassium formed sulfonic group were hardly detected at the distance of 10 mu m from the hole's center in the fabricated area.

    DOI

  • Adhesion Improvement of Perfluoro-sulfonic Acid Membrane by UV irradiation for PEFC Performance

    Fumiya Shiraki, Yuji Oshima, Akihiro Oshima, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   22 ( 3 ) 335 - 340  2009

     View Summary

    Perfluoro-sulfonic acid (PFSA) membranes were exposed to UV for the improvement of surface adhesion property. The photochemical effect of PFSA was evaluated by UV-visible spectroscopy. The changes of the chemical structure of UV-exposed PFSA were studied by electron spin resonance (ESR) and Fourier transform infrared (FTIR) spectroscopies. ESR spectra revealed the presence of peroxy radicals. Moreover, the results of FTIR would be indicating the decomposition of side chains of PFSA. To evaluate the adhesion properties after UV exposure, the shearing stresses of laminations were measured. The lamination of UV-exposed PFSA showed higher adhesion property than that of unexposed PFSA. A membrane electrode assembly (MEA) consisting of UV-exposed PFSA was fabricated by a hot-press method for the fuel cell operations. The obtained MEA showed higher cell performance than that of the MEA of unexposed PFSA.

    DOI

  • 早稲田大学におけるフォトカソードRF電子銃を用いたパルスラジオリシスシステムの現状

    藤田晃宏, 坂上和之, 野本知章, 濱義昌, 保坂勇志, 鷲尾方一, 柏木茂, 黒田隆之助, 丑田公規

    放射線化学討論会講演要旨集   51st   179 - 180  2008.10

    J-GLOBAL

  • 軟X線顕微鏡の開発に向けたフォトレジストの評価と感光法の検討

    五輪智子, 樫野多加志, 大島明博, 裏川達也, 五十嵐千明, 増田明彦, 坂上和之, 濱義昌, 鷲尾方一, 黒田隆之助, 柏木茂, 丑田公規

    放射線化学討論会講演要旨集   51st   139 - 140  2008.10

    J-GLOBAL

  • 早稲田大学におけるフォトカソードRF電子銃を用いたパルスラジオリシスシステムの現状

    藤田晃宏, 小宮圭太, 坂上和之, 野本知章, 濱義昌, 鷲尾方一, 柏木茂, 勝村庸介, 室屋裕佐, 黒田隆之助, 丑田公規

    アイソトープ・放射線研究発表会要旨集   45th   80  2008.06

    J-GLOBAL

  • 早稲田大学におけるCs‐TeフォトカソードRF電子銃の現状

    鈴木達也, 五十嵐千明, 浦川順治, 樫野多加志, 柏木茂, 加藤雄太, 神谷好郎, 栗木雅夫, 黒田隆之助, 小宮圭太, 五輪智子, 坂上和之, 高富俊和, 照沼信浩, 野本知章, 濱義昌, 早野仁司, 広瀬立成, 藤田晃宏, 増田明彦, 村田亜希, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   45th   75  2008.06

    J-GLOBAL

  • 早稲田大学における逆コンプトン散乱X線源のマルチパルス化計画と進捗状況

    五十嵐千明, 大島明博, 五輪智子, 坂上和之, 濱義昌, 増田明彦, 鷲尾方一, 丑田公規, 浦川順治, 早野仁司, 柏木茂, 黒田隆之助

    アイソトープ・放射線研究発表会要旨集   45th   76  2008.06

    J-GLOBAL

  • パルスレーザー共振器の装置開発

    荒木栄, 浦川順治, 大森恒彦, 奥木敏行, 栗木雅夫, 坂上和之, 清水洋孝, 高橋徹, 照沼信浩, 広瀬立成, 舟橋義聖, 本田洋介, 李小平, 鷲尾方一

    Research Report. NIFS-MEMO Series   ( 55 ) 277 - 280  2008.03

    J-GLOBAL

  • 架橋PTFEの集束イオンビームによる微細加工とその高機能化に関する研究

    高澤侑也, 福武直之, 裏川達也, 大島明博, 鷲尾方一, 岡本一将, 田川精一

    日本化学会講演予稿集   88th ( 1 )  2008

    J-GLOBAL

  • 架橋PTFEの集束イオンビームによる微細加工とその高機能化に関する研究

    高澤侑也, 福武直之, 裏川達也, 大島明博, 鷲尾方一, 岡本一将, 田川精一

    アイソトープ・放射線研究発表会要旨集   45th  2008

    J-GLOBAL

  • 集束イオンビームによる架橋PTFEのナノスケール微細パターンの作成

    福武直之, 裏川達也, 高澤侑也, 三好のぞみ, 大島明博, 鷲尾方一, 岡本一将, 松井良憲, 関修平, 田川精一

    高分子学会予稿集(CD-ROM)   57 ( 1 Disk1 )  2008

    J-GLOBAL

  • 集束イオンビームを用いたフッ素系高分子のナノ加工

    福武直之, 高澤侑也, 五輪智子, 裏川達也, 鷲尾方一, 大島明博, 岡本一将, 田川精一

    放射線化学討論会講演要旨集   51st  2008

    J-GLOBAL

  • 26aZL-14 Development of a Soft X-ray Source based on Inverse Compton Scattering at Waseda University

    Gowa Tomoko, Kashiwagi Shigeru, Ushida Kiminori, Igarashi Chiaki, Kashino Takashi, Sakaue Kazuyuki, Masuda Akihiko, Washio Masakazu, Urakawa Junji, Hayano Hitoshi, Kuroda Ryunosuke

    Meeting Abstracts of the Physical Society of Japan   63 ( 0 ) 130 - 130  2008

    CiNii

  • 26aZL-13 The development of the compact pico-second pulse radiolysis system at Waseda University

    Nomoto Tomoaki, Komiya Keita, Sakaue Kazuyuki, Fujita Akihiro, Washio Masakazu, Kuroda Ryunosuke, Kashiwagi Shigeru, Ushida Kiminori

    Meeting Abstracts of the Physical Society of Japan   63 ( 0 ) 130 - 130  2008

    CiNii

  • Development of Multi-bunch Photo-Cathode RF Gun in Kyoto University

    KII TOSHITERU, URAKAWA JUNJI, SAKAUE KAZUYUKI, MURATA AKI, WASHIO MASAKAZU, OHGAKI HIDEAKI, MASUDA KAI, ZEN HEISYUN, SASAKI SATOSHI, SIIYAMA TAKUMI, KURODA RYUNOSUKE, KURIKI MASAO, TERUNUMA NOBUHIRO

    Proceedings of Annual / Fall Meetings of Atomic Energy Society of Japan   2008 ( 0 ) 123 - 123  2008

     View Summary

    京都大学光陰極高周波電子銃開発の現状と、京都大学自由電子レーザー施設へ導入した際の性能予測について報告する。

    DOI CiNii

  • 23aSM-7 Result and development of gamma-rays generation experiment with optical cavity for ILC polarized positron source at KEK-ATF

    Ushio Yasuaki, Terunuma Nobuhiro, Hirose Tachishige, Funahashi Yoshisato, Pei Guoxi, Honda Yosuke, Miyoshi Shuhei, Li XiaoPing, Washio Masakazu, Araki Sakae, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki, Shimizu Hirotaka, Takahashi Tohru

    Meeting Abstracts of the Physical Society of Japan   63 ( 0 ) 23 - 23  2008

    CiNii

  • 26aZL-12 Development of a Compact X-ray Source with a Pulsed-Laser Super-Cavity in LUCX (5)

    Sakaue K, Honda Y, Muto T, Yokoyama H, Washio M, Araki S, Urakawa J, Sasao N, Takano M, Taniguchi T, Terunuma N, Higashi Y, Fukuda M

    Meeting Abstracts of the Physical Society of Japan   63 ( 0 ) 130 - 130  2008

    CiNii

  • 24aZL-1 Gamma-rays generation experiment with optical cavity for ILC polarized positron source at KEK-ATF

    Araki Sakae, Hirose Tachishige, Funahashi Yoshisato, Pei Guoxi, Honda Yosuke, Miyoshi Shuhei, Li Xiao Ping, Washio Masakazu, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kuriki Masao, Sakaue Kazuyuki, Shimizu Hirotaka, Takahashi Tohru, Terunuma Nobuhiro

    Meeting Abstracts of the Physical Society of Japan   63 ( 0 ) 121 - 121  2008

    CiNii

  • 23aZL-9 Development of a Cs-Te photocathode RF-Gun system and Beam diagnostics at Waseda University

    Murata Aki, Hama Yoshimasa, Hirose Tachishige, Fujita Akihiro, Masuda Akihiko, Washio Masakazu, Urakawa Junji, Takatomi Toshikazu, Terunuma Nobuhiro, Hayano Hitoshi, Kashiwagi Shigeru, igarashi Chiaki, Kamiya Yoshio, Kuriki Masao, Kuroda Ryunosuke, Kashino Takashi, Kato Yuta, Komiya Keita, Gowa Tomoko, Sakaue Kazuyuki, Suzuki Tatuya, Nomoto Tomoaki

    Meeting Abstracts of the Physical Society of Japan   63 ( 0 ) 118 - 118  2008

    CiNii

  • Improvement of an S-band RF-Gun cavity with a CS-TE photo-cathode

    A. Murata, Y. Kato, K. Sakaue, T. Suzuki, Y. Hama, T. Hirose, M. Washio, J. Urakawa, T. Takatomi, N. Terunuma, H. Hayano, S. Kashiwagi, Y. Kamiya, R. Kuroda, M. Kuriki

    EPAC 2008 - Contributions to the Proceedings     721 - 723  2008.01

     View Summary

    A 1.6 cell S-band photo-cathode RF-Gun is one of the good alternatives of the short pulse electron source. Therefore, we are operating as a high brightness short pulse electron source for studying a reaction of radiation chemistry [1], an inverse Compton scattering at Waseda University [2] and as an injector at KEK-ATF. To improve an electron beam quality and reduce a dark current, our group decided to improve the RF-Gun cavity. The resonance frequency tuning of the half cell of existing RF-Gun was performed by the torque control of Helicoflex seal on the cathode plate and two moving rod type tuners with a tuning hole were installed on the full cell. Newly designed RF-Gun cavity has four compact tuners on each cell, which can be tune the frequency to deform the cavity wall, to remove the Helicoflex seal and tuning holes that were considered to be the major cause of electric discharge and/or dark current source [3]. According to these improvements, the Q-value and shunt impedance of the cavity is 20% larger than that of existing guns. As the result, the reduction of dark current is demonstarated and the beam energy is reached up to 5.5MeV at 10MW RF input.

  • Development of a compact X-ray source based on laser-compton scattering with a pulsed-laser super-cavity

    K. Sakaue, M. Washio, S. Araki, M. Fukuda, Y. Higashi, Y. Honda, T. Taniguchi, T. Terunuma, J. Urakawa, N. Sasao

    EPAC 2008 - Contributions to the Proceedings     1872 - 1874  2008.01

     View Summary

    A compact and high quality x-ray source is required for various field, such as medical diagnosis, drug manufacturing and biological sciences. Laser-Compton based x-ray source that consist of a compact electron storage ring and a pulsed-laser super-cavity is one of the solutions of a compact x-ray source. Pulsed-laser super-cavity has been developed at KEK-ATF for a compact high brightness x-ray source. The pulsed-laser super-cavity enables to make high peak power and small waist laser at the collision point with the electron beam. Recently, 357MHz mode-locked Nd:VAN laser pulses can be stacked stably in a 420mm long Fabry-Perot cavity with 2.5kW average power in our R&amp;D. On the other hand, we have succeeded to stack the pulsed amplified laser in the super-cavity. This indicates that the number of X-ray is multiplied due to the gain in the amplification system to synchronize the pulsed pump to the beam. In view of this successful result, we have started an X-ray generation experiment using a super-cavity and a multi-bunch electron beam at KEK-LUCX. Development of the super-cavity and the results of X-ray generation experiment will be presented at the conference.

  • Development of laser system for compact laser compton scattering x-ray source

    R. Kuroda, H. Toyokawa, M. Koike, K. Yamada, T. Gowa, A. Masuda, K. Sakaue, M. Washio, S. Kashiwagi, T. Nakajyo, F. Sakai

    EPAC 2008 - Contributions to the Proceedings     1878 - 1880  2008.01

     View Summary

    A compact X-ray source via laser Compton scattering is required for biological, medical and industrial science because it has many benefits about generated X-rays such as short pulse, quasi-monochromatic, energy tunability and good directivity. Our X-ray source is conventionally the single collision system between an electron pulse and a laser pulse. To increase X-ray yield, we have developed a multi-collision system with a multi-bunch electron beam and a laser optical cavity. The multi-bunch electron beam has been successfully generated from a Cs2Te photocathode rf gun using a multi-pulse UV laser system. The laser optical cavity will be built like the regenerative amplification including the collision point between the electron pulse and the laser pulse to enhance the laser peak power per 1 collision on laser Compton scattering (LCS).

  • Design of linac based compact x-ray source via inverse Compton scattering at Waseda University

    A. Masuda, T. Gowa, C. Igarashi, T. Kashino, N. Mitsuda, K. Sakaue, M. Washio, R. Kuroda, S. Kashiwagi, H. Hayano, J. Urakawa, K. Ushida

    EPAC 2008 - Contributions to the Proceedings     166 - 168  2008.01

     View Summary

    A table-top size soft X-ray source based on inverse Compton scattering has been developed at Waseda University. We have already succeeded in generating X-rays via inverse Compton scattering between 4.6 MeV electron beam generated from a photocathode RF-gun and 1047 nm Nd:YLF laser. The energy of the X-ray is within the !Hwater window !Iegion which can be applied to the soft X-ray microscope for biological observation. In 2007, new RF-gun cavity with Cs-Te photocathode in place of copper has been installed. The energy of electron beam has become up to 5.5 MeV due to the increase of Q-value of the gun cavity. With this achievement, generated X-ray energies will cover overall the !Hwater window !Iregion. We have been planning a multi-pulse inverse Compton scattering X-ray generation system in order to enhance a luminous intensity of the X-rays. For this purpose, we are considering a multi-pulse UV laser system for generating a multi-bunch electron beam, the method for beam loading compensation, and the multi-pulse IR laser system for the Compton collisions.

  • Compact EUV source based on laser compton scattering between micro-bunch electron beam and CO<inf>2</inf>laser pulse

    S. Kashiwagi, R. Kato, G. Isoyama, R. Kuroda, J. Urakawa, K. Sakaue, A. Masuda, T. Nomoto, T. Gowa, M. Washio

    EPAC 2008 - Contributions to the Proceedings     1869 - 1871  2008.01

     View Summary

    High-power extreme ultra-violet (EUV) sources are required for next generation semiconductor lithography. We start developing a compact EUV source in the spectral range of 13-14 nm, which is based on laser Compton scattering between a 7 MeV micro-bucnhed electron beam and a high intensity CO2laser pulse. The electron beam extracted from a DC photocathode gun is micro-bunched using laser modulation techinque with the Compton wavelength at a harmonic of the seeding laser [1] before the main laser Compton scattering for EUV radiation. A considerating scheme for the compact EUV source based on laser Compton scattering with micro-bunched electron beam and the anaritical study of micro-bunch generation are described in this papar. A plan of test experiment generating micro-bunched electron beam will be also introduced in this conference.

  • Development of sulfonated FEP-Nafion hybrid proton exchange membranes for PEFC

    Y. Sato, K. Fujii, N. Mitani, A. Matsuura, T. Kakigi, F. Muto, J. Li, A. Oshima, M. Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   265 ( 1 ) 213 - 216  2007.12

     View Summary

    The performance of polymer electrolyte fuel cell (PEFC) is affected by an interfacial property between a proton exchange membrane (PEM) and electrodes. Thus, to develop a well-laminated membrane electrode assembly (MEA), a hybrid PEM (FN) was fabricated by mixing a radiation grafted membrane (sulfonated FEP) with ionomer (Nation (R) dispersion) which is applied to coat the interface of the PENI and electrodes.
    The obtained FN, sulfonated FEP and Naflon (R) 112 were characterized in terms of water uptake, ion exchange capacity (IEC), polarization performance and electrochemical impedance. FN showed high IEC and water uptake, which would induce the highest ionic conductivity (IC) among tested PEW In terms of FN, the interface between the PEM and electrodes should have been inaproved because FN showed the lowest charge transfer resistance than other tested PEMs. The high IC and improved interface between the PEM and electrodes resulted in the best cell performance of FN in tested PEMs. (C) 2007 Elsevier B.V. All rights reserved.

    DOI

  • Improvements in time resolution and signal-to-noise ratio in a compact pico-second pulse radiolysis system

    Hiroyuki Nagai, Masaaki Kawaguchi, Kazuyuki Sakaue, Keita Komiya, Tomoaki Nomoto, Yoshio Kamiya, Yoshimasa Hama, Masakazu Washio, Kiminori Ushida, Shigeru Kashiwagi, Ryunosuke Kuroda

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   265 ( 1 ) 82 - 86  2007.12

     View Summary

    A compact pico-second pulse radiolysis system has been developing at Waseda University for studying primary processes in radiation chemistry. The system is composed of a photo-injector system and a pico-second all-solid-state laser system. An infrared (IR) and an ultraviolet (UV) laser pulses are obtained from mode-locked Nd:YLF laser system and used for generation of the white light continuum as a probe light and the irradiation to the Cu cathode of a photo-cathode RF-gun, respectively. To improve signal-to-noise (S/N) ratio and time resolution of this pulse radiolysis system, we optimized both probe light and pump electron beam. As a result, our pico-second pulse radiolysis system has been enough to study the primary processes of radiation chemistry. The experimental results and the improvements of our system are described in this paper. (C) 2007 Elsevier B.V. All rights reserved.

    DOI

  • Numerical evaluation of oscillator fel with multi-bunch photo-cathode RF-gun in Kyoto university

    Hideaki Ohgaki, Toshiteru Kii, Kai Masuda, Satoshi Sasaki, Takumi Shiiyama, Heishun Zen, Ryunosuke Kuroda, Masao Kuriki, Nobuhiro Terunuma, Junji Urakawa, Yoshio Kamiya, Masakazu Washio

    29th International Free Electron Laser Conference, FEL 2007     390 - 393  2007.12

     View Summary

    Numerical evaluations have been performed to install a photo-cathode RF-gun into an oscillator FEL system which has been developed in Kyoto University. The original FEL system was consisted of a 4.5-cell thermionic RF gun with S-band accelerator tube of 3-m to oscillate the mid-infrared FEL. The electron beam properties have been evaluated from an RF-gun to an FEL by using PARMELA and ELEGANT. On the other hand, the FEL parameters have been calculated with GENESIS which takes the optical cavity into account. The evaluated peak current of the electron beam was 10-50 times as high as those with the thermionic RF-gun. Since the oscillator FEL requires a multi-bunch electron beam, evaluation of the round-trip development of the FEL has been also performed by a 100 bunch train beam. The results showed that the FEL gain saturation was achieved within 3 round-trips.

  • 早稲田大学加速器システムにおける高品質電子ビーム生成の現状~Cs‐TeカソードRF‐Gunの現状報告と今後の展望~

    村田亜希, 五十嵐千明, 樫野多加志, 加藤雄太, 小宮圭太, 五輪智子, 坂上和之, 鈴木達也, 野本知章, 濱義昌, 広瀬立成, 藤田晃宏, 増田明彦, 鷲尾方一, 浦川順治, 栗木雅夫, 高富俊和, 照沼信浩, 早野仁司, 柏木茂, 神谷好郎, 黒田隆之助

    放射線化学討論会講演要旨集   50th   189 - 190  2007.10

    J-GLOBAL

  • 早稲田大学におけるパルスラジオリシスシステムの現状と今後の展望

    小宮圭太, 坂上和之, 野本知章, 濱義昌, 藤田晃宏, 鷲尾方一, 丑田公規, 柏木茂, 黒田隆之助

    放射線化学討論会講演要旨集   50th   191 - 192  2007.10

    J-GLOBAL

  • 軟X線顕微鏡の開発に向けた化学増幅型フォトレジストの評価

    五輪智子, 五十嵐千明, 丑田公規, 大島明博, 樫野多加志, 柏木茂, 黒田隆之助, 坂上和之, 濱義昌, 増田明彦, 鷲尾方一

    放射線化学討論会講演要旨集   50th   127 - 128  2007.10

    J-GLOBAL

  • 早稲田大学におけるCs‐TeカソードRF電子銃の開発

    加藤雄太, 五十嵐千明, 樫野多加志, 小宮圭太, 五輪智子, 坂上和之, 鈴木達也, 野本知章, 濱義昌, 広瀬立成, 藤田晃宏, 増田明彦, 村田亜希, 鷲尾方一, 浦川順治, 栗木雅夫, 高富俊和, 照沼信浩, 早野仁司, 黒田隆之助, 柏木茂, 神谷好郎

    日本物理学会講演概要集   62 ( 2 ) 118  2007.08

    J-GLOBAL

  • 早稲田大学におけるRF電子銃を用いたコンパクトなピコ秒パルスラジオリシスシステムの改良と評価

    野本知章, 永井宏幸, 小宮圭太, 坂上和之, 神谷好郎, 濱義昌, 鷲尾方一, 丑田公規, 柏木茂, 黒田隆之助

    アイソトープ・放射線研究発表会要旨集   44th   70  2007.06

    J-GLOBAL

  • He2+イオン照射ポリテトラフルオロエチレンの構造変化に関する研究

    大島明博, 三好のぞみ, 松浦章雄, 村田勝義, 岡壽崇, 工藤久明, 村上健, 加藤悦子, 鷲尾方一, 濱義昌

    高分子学会予稿集(CD-ROM)   56 ( 1 Disk1 ) 3PA057  2007.05

    J-GLOBAL

  • Polarized positron generation based on laser Compton scheme and its polarization measurements

    Kazuyuki Sakau, Taku Saito, Issei Yamazaki, Ryunosuke Kuroda, Masakazu Washio, Tachishige Hirose, Tsunehiko Omori, Toshiyuki Okuci, Yoshimasa Kurihara, Junji Urakawa, Masafumi Fukuda, Masahiro Nomura, Ayumu Ohashi

    INTERNATIONAL JOURNAL OF MODERN PHYSICS B   21 ( 3-4 ) 519 - 526  2007.02

     View Summary

    We have proposed a new scheme for polarized positron production, consisting of two quantum processes i.e. inverse Compton scatterings of circularly polarized laser light on high-quality electron beams and successive electron-positron pair creations. Using a circularly polarized laser beam of 532 nm scattered off a high-quality electron beam with the energy of 1.28 GeV, we have demonstrated for the first time productions of highly polarized positrons positrons with an intensity of 2x10(4) e(+)/bunch and an average energy of 36 MeV. Hence an average polarization of positrons was determined as 73 +/- 15(stat)+/- 19(syst)% by means of a newly designed positron polarimeter.

  • 芳香族系高分子の照射温度依存性~広域帯誘電特性と熱物性~

    大島明博, 中西真大, 野嵜龍介, 丑田公規, 鷲尾方一

    放射線化学討論会講演要旨集   50th  2007

    J-GLOBAL

  • Suppression of the long-term degradation of polymer by SiO2 coating

    Toshitaka Oka, Mitsuaki Kondo, Akihiro Oshima, Masakazu Washio, Minoru Iwata, Hisaaki Kudo, Yosuke Katsumura, Kenji Ito, Yoshinori Kobayashi, Takeshi Murakami, Yoshimasa Hama

    ACS Symposium Series 978     131 - 139  2007

    DOI

  • Heavy ion beam induced phenomena in polytetrafluoroethylene

    Akihiro Oshima, Katsuyoshi Murata, Toshitaka Oka, Nozomi Miyoshi, Akio Matsuura, Hisaaki Kudo, Takeshi Murakami, Etsuko Katoh, Masakazu Washio, Yoshimasa Hama

    Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms   265   314 - 319  2007

    DOI

  • 28pSH-6 Soft X-ray Generation based on Inverse Compton Scattering at Waseda University

    Masuda Akihiko, Moriyama Ryo, Washio Masakazu, Ushida Kiminori, Urakawa Junji, Kashiwagi Shigeru, Kamiya Yoshio, Kuroda Ryunosuke, Gowa Tomoko, Sakaue Kazuyuki, Hayano Hitoshi

    Meeting Abstracts of the Physical Society of Japan   62 ( 0 ) 24 - 24  2007

    CiNii

  • 21pZG-10 Development of a Soft X-ray Source based on Inverse Compton Scattering at Waseda University

    Masuda Akihiko, Sakaue Kazuyuki, Hayano Hitoshi, Moriyama Ryo, Washio Masakazu, Igarashi Chiaki, Ushida Kiminori, Urakawa Junji, Kashino Takashi, Kashiwagi Shigeru, Kamiya Yoshio, Kuroda Ryunosuke, Gowa Tomoko

    Meeting Abstracts of the Physical Society of Japan   62 ( 0 ) 123 - 123  2007

    CiNii

  • Sバンド光陰極高周波電子銃の製作

    T Kii, H Ohgaki, K Masuda, H Zen, S Sasaki, T Shiiyama, R Kuroda, J Urakawa, N Terunuma, T Takatomi, N Kudoh, M Kuriki, A Murata, K Sakaue, M Washio, Y Kamiya

    第5回高周波電子銃研究会,早稲田大学,2007.12.4    2007  [Refereed]

  • 21pZG-9 Development of a Compact X-ray Source Using Pulsed-Laser Super-Cavity in LUCX (3)

    Sakaue Kazuyuki, Liu shengguang, Sasao Noboru, Yokoyama Hirokazu, Muto Toshiya, Takano Mikio, Washio Masakazu, Araki Sakae, Urakawa Junji, Terunuma Nobuhiro, Taniguchi Takashi, Higashi Yasuo, Fukuda Masafumi, Honda Yosuke

    Meeting Abstracts of the Physical Society of Japan   62 ( 0 ) 123 - 123  2007

    CiNii

  • Study on PEFC membrane based on crosslinked FEP using EB-grafting

    Akio Matsuura, Tomoyuki Kakigi, Yukiko Sato, Kazuki Fujii, Naohiro Mitani, Jingye Li, Akihiro Oshima, Masakazu Washio

    MACROMOLECULAR SYMPOSIA   249   221 - 227  2007

     View Summary

    Polymer electrolyte fuel cell (PEFC) membranes based on crosslinked tetrafluoroethylene-co-hexafluoropropylene (FEP) have been fabricated by preirradiation grafting method. The chemical structures of crosslinked materials have been analyzed by Differential Scanning Calorimeter (DSC) and F-19 solid-state Nuclear Magnetic Resonance (NMR) spectroscopy. The radical yields of irradiated samples were measued by Electron Spin Resonance (ESR), and the mechanism of grafting reaction has been discussed. The styrene grafted materials were sulfonated by chlorosulfonic acid. The ion exchange capacity of the obtained sulfonated crosslinked FEP (S-FEP-X) showed 2.0 to 2.4 meq/g, which were 2.2 to 2.7 times higher than that of Nafion((R))112. Glass transition temperatures (T-g) of S-FEP-X were almost independent on crosslinking dose of FEP, and show about 96 OC, which are slightly higher than that of Nafion((R)). The electrochemical properties of the membranes have been measured, and cell performances of them have been evaluated. Ionic conductivities (ICs) of S-FEP-X are 1.2 to 1.6 times higher than that of Nafion((R)). The higher network densities gave the higher open circuit voltage (OCV). The power density of S-FEP-6ookGy was about 10% higher than that of Nafion((R)) at 500mA/cm(2). Thus, the obtained sulfonated membranes can be expected to apply for high efficiency PEFC.

    DOI

  • Direct photo-etching and surface modification of polytetrafluoroethylene by synchrotron radiation

    Toshiyuki Hyuga, Akihiro Oshima, Atsushi Mori, Hiroyuki Nagai, Nozonmi Miyoshi, Tatspya Urakawa, Naoyuki Fukutake, Takanori Katoh, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   20 ( 1 ) 107 - 112  2007

     View Summary

    Micromachining of various polytetrafluoroethylene (sintered PTFE, non-sintered PTFE and expand PTFE) using synchrotron radiation (SR) direct photo-etching has been carried out, and also the etched surface was studied by various analyses. The thin sintered (10 mu m) and expand (80 mu m) PTFE films were piled up, and the layered PTFE and non-sintered FIFE (1.2mm) irradiated by SR below the melting temperature, in order to clarify the degree of chemical and physical changes according to the depth from the etched surface. SR irradiated films were examined by F-19 solid-state magic-angle spinning (MAS) NMR spectroscopy and differential scanning calorimetric (DSC) analysis. The results showed that the modification by SR irradiation depended on the depth from the surface: within about 60 mu m from the surface, the network structure formation would be induced even in its solid state; in deeper regions, the chain scission would be dominant. Furthermore, SR was irradiated for non-sintered PTFE with different molecular conformation, compared with usual PTFE. It was found that non-sintered PTFE was also crosslinked in the surface region. Moreover, the sintered and non-sintered PTFE could be etched well. In the case of non-sintered PTFE, the distance of the non-etched remaining structures shrank by heat-treatment at 360 degrees C. The shrinking was about 20%.

    DOI

  • High-aspect-ratio micromachining of fluoropolymers using focused ion beam

    Yoshinori Matsui, Nozomi Miyoshi, Akihiro Oshima, Shu Seki, Masakazu Washio, Seiichi Tagawa

    ION-BEAM-BASED NANOFABRICATION   1020   61 - 66  2007

     View Summary

    Poly(tetrafluoroethylene) (PTFE) microstructure with high aspect ratio (&gt; 200) and without solid debris along the edge was fabricated with high etch rate using FIB. Evolution of PTFE by FIB is responsible for the high aspect ratio, the high etch rate, and the no solid debris. Roughness of etched surface of the PTFE increases with fluence, although edge of the etched area has good profiles. The etch mechanism seems to be complicated.

  • Development of compact EUV source based on laser compton scattering

    S. Kashiwagi, R. Kato, J. Yang, G. Isoyama, K. Sakaue, A. Masuda, T. Nomoto, T. Gowa, M. Washio, R. Kuroda, J. Urakawa

    2007 IEEE PARTICLE ACCELERATOR CONFERENCE, VOLS 1-11     2043 - +  2007

     View Summary

    High-power extreme ultra-violet (EUV) sources are required for next generation semiconductor lithography. We start developing a compact EUV source in the spectral range of 13-14 nm, which is based on laser Compton scattering between a 7 MeV electron beam and a high intensity CO2 laser pulse. Before the main laser Compton scattering for EUV radiation, the electron beam is pre-bunched by a high power seeding laser pulse with the Compton wavelength at a harmonic of the seeding laser [1]. In this paper, we describe the preliminary consideration for the EUV source development and a plan of experiment generating micro-bunched electron beam.

    DOI

  • Development of pulsed-laser super-cavity for compact X-ray source based on laser-Compton scattering

    K. Sakaue, M. Washio, S. Araki, M. Fukuda, Y. Higashi, Y. Honda, T. Taniguchi, N. Terunuma, J. Urakawa, N. Sasao, H. Yokoyama, M. Takano

    2007 IEEE PARTICLE ACCELERATOR CONFERENCE, VOLS 1-11     3233 - +  2007

     View Summary

    A compact and high quality x-ray source is required from various fields, such as medical diagnosis, drug manufacturing and biological sciences. Laser-Compton based x-ray source that consist of a compact electron storage ring and a pulsed-laser super-cavity is one of the solutions of compact x-ray source. Pulsed-laser super-cavity has been developed for a compact high brightness x-ray sources at KEK-ATF. The pulsed-laser super-cavity increases the laser power and stably makes small laser beam size at the collision point with the electron beam. Recently, 357MHz mode-locked Nd:VAN laser pulses can be stacked stably in a 420mm long Fabry-Perot cavity with 600 enhancement in our R&D. Therefore, we have planned a compact hard x-ray source using 40MeV multi-bunch electrons and a pulse stacking technology with 42cm Fabry-Perot cavity. (LUCX Project at KEK) The photon flux is multiplied with the number of bunches by using multi-bunch beam and supercavity. Development of the super-cavity and present result of LUCX will be presented at the conference.

    DOI

  • Development of an S-band Cs2Te-cathode RF gun with new RF tuners

    Y. Kamiya, Y. Kato, A. Murata, K. Sakaue, M. Washio, T. Takatomi, J. Urakawa, N. Terunuma, M. Kuriki, N. Kudoh, R. Kuroda

    2007 IEEE PARTICLE ACCELERATOR CONFERENCE, VOLS 1-11     2052 - +  2007

     View Summary

    A photo-cathode RF gun is one of the good alternatives for the electron injector, because of its high gradient on the electron emitter causing small beam emittance, and better operationality especially for electron bunch length. Therefore, several institutes which study FEL [1], early response of a radiochemical processes [2, 3], and/or advanced accelerator technologies specially for International Linear Collider (ILC) [4] adopted the photo-cathode RF gun as their injector.
    In this paper, we present a modified RF gun with new compact tuners and show results of a conditioning study using high power RF field. A starting point of this study is an design of the S-band CS2Te-cathode RF gun used in the Accelerator Test Facility of KEK (KEK-ATF).[4].

    DOI

  • Improvement of soft X-ray generation system based on laser Compton scattering

    T. Gowa, A. Masuda, R. Moriyama, K. Sakaue, Y. Kamiya, M. Washio, R. Kuroda, S. Kashiwagi, K. Ushida, H. Hayano, J. Urakawa

    2007 IEEE PARTICLE ACCELERATOR CONFERENCE, VOLS 1-11     3230 - +  2007

     View Summary

    A compact X-ray source is required in various fields such as biological science and material development. At Waseda University, a table-top size soft X-ray source based on laser Compton scattering has been developed. Using 1047 nm laser beam (Nd:YLF) and 4.6 MeV electron beam generated from a photo-cathode RF-gun, we had already succeeded in generating laser Compton X-rays [1]. The energies are within the "water window" region (250-500 eV) [2] which can be applied to biological studies. For good signal to noise (S/N) ratio and more photons, we remodeled our collision chamber and laser amplifier system. With these modifications, the X-ray photons detected by a micro channel plate (MCP) have increased tenfold to reach 312/pulse. All the generated photons was estimated to be 3.28 x 10(4). Moreover, we succeeded in generating soft Xrays stably for more than 10 hours. Good SIN ratio stable X-rays have made it possible to observe the beam-laser interaction precisely.

    DOI

  • Development of photocathode Rf gun and laser system for multi-collision laser Compton scattering

    R. Kurode, H. Toyokawa, M. Yasumoto, N. Sei, H. Ogawa, M. Koike, K. Yamada, T. Nakajyo, F. Sakai, T. Yanagida, T. Gowa, A. Masuda, R. Moriyama, Y. Kamiya, K. Sakaue, M. Washio, S. Kashiwagi

    2007 IEEE PARTICLE ACCELERATOR CONFERENCE, VOLS 1-11     3236 - +  2007

     View Summary

    The laser cavities of Ti:Sa and Nd: YLF laser have been designed for the multi-collision laser Compton scattering (Multi-LCS) in order to enhance the X-ray yields of the LCS hard and soft X-ray source. This cavity is like the regenerative amplification including a laser crystal and a collision point for LCS. The enhanced X-ray yield was estimated more than about I x 109 Is using the intra-cavity stored energy. In this conference, we will describe details of the laser cavity design for the Multi-LCS and future plans of the LCS X-ray sources.

    DOI

  • ILC positron source based on laser compton

    M. Kuriki, S. Araki, Y. Higashi, Y. Honda, Y. Kurihara, T. Okugi, T. Omori, T. Taniguchi, N. Terunuma, J. Urakawa, M. Fukuda, K. Hirano, M. Takano, T. Hirose, K. Sakaue, M. Washio, T. Takahashi, H. Shimizu, A. Tsunemi, F. Zimmermann, H. Braun, M. Korostelev, L. Rinolfi, D. Schulte, E. Bulyak, P. Gladkikh, K. Moenig, A. Variola, F. Zomer, X. Artru, R. Chehab, A. Chevallier, V. Strakhovenko, J. Gao, S. Guiducci, P. Raimondi, V. Soskov

    PSTP 2007   980   92 - +  2007

     View Summary

    Positron generation is one of the most difficult technical challenges among the ILC (International Linear Collider) subsystems. A positron source based on Laser Compton back scattering is an attractive and advanced option for the ILC positron source. Here, the positrons are generated, via the pair creation process, from high energy gamma rays which themselves are produced by Compton scattering of laser photons off a high-energy electron beam. Polarized positrons can be generated by employing a circularly polarized laser. The positron polarization is easily controlled and switched by changing the laser polarity. The electron beam can be unpolarized. The required electron energy is only a few GeV (in contrast, the "undulator scheme", another advanced option, requires at least 100 GeV or more) and the system can be prototyped and tested prior to the real construction. The laser Compton technology has many other applications like advanced X-ray sources and a good synergy is expected. In addition, this technology can be a powerful driving force for the ILC project attracting many researchers from outside the ILC community. The ILC positron source is a technical challenge and it will be realized only if the latest technologies are integrated seamlessly with the necessary R&D efforts for system specific issues. The latest technologies include high power lasers, high brightness electron beams, high finesse optical cavities for as laser-beam interaction point, etc. We present the design status and the related experimental efforts for the ILC positron source based on Laser Compton scattering. The respective advantages of various options for the electron beam (based on Linac, storage ring, and ERL) are also compared.

    DOI

  • Preparation of the crosslinked polyethersulfone films by high-temperature electron-beam irradiation

    Jingye Li, Akihiro Oshima, Takaharu Miura, Masakazu Washio

    POLYMER DEGRADATION AND STABILITY   91 ( 12 ) 2867 - 2873  2006.12

     View Summary

    The radiation-crosslinked polyethersulfone (RX-PES) films were prepared by means of electron-beam irradiation under nitrogen atmosphere at 230 degrees C, where the temperature is around the glass transition temperature of PES (222 degrees C). The gel formation of RX-PES films was observed when the absorbed doses exceeded 300 kGy, which indicated the crosslinking structure formation. The G(S) of 0.10 and G(X) of 0.23 were calculated according to the Y-crosslinking mechanism. The irradiation was also performed at ambient temperature for comparison. There was no gel formation of the irradiated films even for the absorbed doses as high as 2250 kGy. The thermal properties of the original and irradiated PES films were measured by means of DSC and TGA analyses. The chemical structure of the original and the irradiated films was analyzed by means of FT-IR ATR and UV-vis spectroscopies. (c) 2006 Elsevier Ltd. All rights reserved.

    DOI

  • Performance of membrane electrode assemblies based on proton exchange membranes prepared by pre-irradiation induced grafting

    Jingye Li, Akio Matsuura, Tomoyuki Kakigi, Takaharu Miura, Akihiro Oshima, Masakazu Washio

    JOURNAL OF POWER SOURCES   161 ( 1 ) 99 - 105  2006.10

     View Summary

    Proton exchange membranes (PEMs) were prepared by pre-irradiation induced grafting of styrene (S) or styrene/divinylbenzene (S/DVB) into the radiation-crosslinked polytetrafluoroethylene (RX-PTFE) films and then sulfonated. The thicknesses of the obtained PEMs were lower than 20 mu m and the ion exchange capacity (IEC) values were around 2 meq g(-1). The surfaces of the PEMs and carbon electrodes were coated with Nafion (R) dispersion, and then membrane electrode assembles (MEAs) were prepared by hot-pressing them together. A MEA based on a Nation (R) 112 membrane was also prepared under same procedure for comparison. The performances of the MEAs in a single cell were tested under different cell temperatures and humidifications. Electrochemical impedance spectra (EIS) were measured with ac frequencies which ranged from 100 kHz to 1 Hz at a dc density of 0.5 A cm(-2). The obtained impedance curves in Nyquist representation were semicircular. (c) 2006 Elsevier B.V. All rights reserved.

    DOI

  • Preparation of ion exchange membranes by preirradiation induced grafting of styrene/divinylbenzene into crosslinked PTFE films and successive sulfonation

    Jingye Li, Shogo Ichizuri, Saneto Asano, Fumihiro Mutou, Shigetoshi Ikeda, Minoru Iida, Takaharu Miura, Akihiro Oshima, Yoneho Tabata, Masakazu Washio

    JOURNAL OF APPLIED POLYMER SCIENCE   101 ( 6 ) 3587 - 3599  2006.09

     View Summary

    Ion exchange membranes (IEMs) were prepared by preirradiation induced grafting of styrene with or without divinylbenzene (DVB) into crosslinked polytetrafluoroethylene (RX-PTFE) films and successively sulfonated by chlorosulfonic acid. The effects of the DVB concentration and solvent on the kinetic of the graft polymerization were studied. The ion exchange capacity (IEC) values of the prepared membranes ranging from 1.5 to 2.8 mequiv/g were obtained. The degree of swelling increased with the increase in the degree of grafting, while higher crosslinking density of both the RX-PTFE matrices and the grafts suppressed the degree of swelling. The chemical stabilities of the IEMs were tested by recording the weight of the membranes being soaked in hot H2O2 solutions. The weight-time curves of the prepared membranes showed one-step quick decrease due to the decomposition of the poly(styrene-sulfonic acid) (PSSA) grafts. Higher crosslinking density in both the RX-PTFE matrices and the grafts improved the chemical stability of the IEMs. The ionic conductivity of the IEMs increases with the increase in the IEC values. The IEMs with IEC values higher than 2.2 mequiv/g hold the higher ionic conductivity than that of Nafion (R) 112 membrane. (c) 2006 Wiley Periodicals, Inc.

    DOI

  • 25pWA-9 Dielectric and thermal measurements of plastic materials

    Nozaki R., Nakanishi M., Ohshima A., Ushida K., Washio M.

    Meeting abstracts of the Physical Society of Japan   61 ( 2 ) 306 - 306  2006.08

    CiNii

  • 25pWA-10 The Dielectric Heating Analysis of Plastic Material : Coupled Simulation of Electromagnetic Wave and Heat Conduction

    Okamoto Y., Ushida K., Himeno R., Ahagon A., Nozaki R., Nakanisi M., Oshima A., Washio M.

    Meeting abstracts of the Physical Society of Japan   61 ( 2 ) 306 - 306  2006.08

    CiNii

  • 25pWA-8 Dechlorination from mixtures of plastic wastes using microwave dielectric heating and its physical background

    Ushida Kiminori, Ito Masayuki, Nakao Noboru, Kikuchi Naoki, Nozaki Ryusuke, Washio Masakazu

    Meeting abstracts of the Physical Society of Japan   61 ( 2 ) 306 - 306  2006.08

    CiNii

  • Dechlorination of poly(vinyl chloride) by microwave irradiation I: A simple examination using a commercial microwave oven

    M Ito, K Ushida, N Nakao, N Kikuchi, R Nozaki, K Asai, M Washio

    POLYMER DEGRADATION AND STABILITY   91 ( 8 ) 1694 - 1700  2006.08

     View Summary

    Poly(vinyl chloride) (PVC) was decomposed by microwave (MW) irradiation (2.45 GHz) using a commercial MW oven. The efficiency of dielectric absorption was evaluated quantitatively from the rate of temperature increase on MW irradiation. The efficiency of dielectric heating increased at temperatures above the glass transition temperature (T-g). The decomposition on MW irradiation, monitored using the weight, depended on the initial (preheating) temperature of the sample before irradiation. The degradation time profile with various initial temperatures was shifted along the time axis and was successfully superimposed on a single curve. A pure PVC film was subjected to heating at a constant temperature from 230 degrees C to 310 degrees C, and the rate of weight decrease on heating was measured. The apparent activation energy was 84.4 kJ/mol for a single monomer unit. (c) 2005 Elsevier Ltd. All rights reserved.

    DOI

  • 早稲田大学におけるピコ秒パルスラジオリシスシステムの構築と改善

    小宮圭太, 永井宏幸, 川口昌朗, 丑田公規, 坂上和之, 柏木茂, 黒田隆之助, 大島明博, 濱義昌, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   43rd   70  2006.06

    J-GLOBAL

  • Improving the properties of the proton exchange membranes by introducing alpha-methylstyrene in the pre-irradiation induced graft polymerization

    Jingye Li, Fumihiro Muto, Takaharu Miura, Akihiro Oshima, Masakazu Washio, Shigetoshi Ikeda, Minoru Iida, Yoneho Tabata, Chihiro Matsuura, Yousuke Katsumura

    EUROPEAN POLYMER JOURNAL   42 ( 6 ) 1222 - 1228  2006.06

     View Summary

    New proton exchange membranes (PEMs) were prepared by pre-irradiation induced grafting of ot-methyl styrene (AMS)/styrene (STY)/divinylbenzene (DVB) into the crosslinked polytetrafluoroethylene (RX-PTFE) films and successively sulfonated. The new PEMs showed the improved glass transition temperature and chemical stability as compared with the PEMs prepared by pre-irradiation induced grafting of STY/DVB. The balance of the cost, grafting kinetic, thermal properties and the properties of the resulted proton exchange membrane is the key point of this work. (c) 2005 Elsevier Ltd. All rights reserved.

    DOI

  • 27aRG-10 Development of Pulsed-Laser Super-Cavity for Compact High Flux Hard X-ray Sources

    Sakaue K., Washio M., Takano M., Fukuda M., Araki S., Urakawa J., Taniguchi T., Higashi Y., Honda Y., Sasao N.

    Meeting abstracts of the Physical Society of Japan   61 ( 1 ) 107 - 107  2006.03

    CiNii

  • 27aRG-12 Development of compact picosecond pulse radiolysis system using photo-cathode RF gun

    Nagai Hiroyuki, Kawaguchi Masaaki, Sakaue Kazuyuki, Komiya Keita, Washio Masakazu, Ushida Kiminori, Kashiwagi Shigeru, Kuroda Ryunosuke

    Meeting abstracts of the Physical Society of Japan   61 ( 1 ) 108 - 108  2006.03

    CiNii

  • 27aRG-11 Development of High Brightness Soft X-ray Source Based on Inverse Compton Scattering in Waseda Univ.

    Moriyama R, Hidume K, Saito T, Sakaue K., Washio M., Kuroda R, Kashiwagi S, Hayano H, Urakawa J., Ushida K

    Meeting abstracts of the Physical Society of Japan   61 ( 1 ) 108 - 108  2006.03

    CiNii

  • Efficient propagation of polarization from laser photons to positrons through compton scattering and electron-positron pair creation

    T Omori, M Fukuda, T Hirose, Y Kurihara, R Kuroda, M Nomura, A Ohashi, T Okugi, K Sakaue, T Saito, J Urakawa, M Washio, Yamazaki, I

    PHYSICAL REVIEW LETTERS   96 ( 11 )  2006.03

     View Summary

    We have demonstrated for the first time the production of highly polarized short-pulse positrons with a finite energy spread in accordance with a new scheme that consists of two-quantum processes, such as inverse Compton scattering and electron-positron pair creation. Using a circularly polarized laser beam of 532 nm scattered off a high-quality, 1.28 GeV electron beam, we have obtained polarized positrons with an intensity of 2x10(4) e(+)/bunch. The magnitude of positron polarization has been determined to be 73 +/- 15(stat)+/- 19(syst)% by means of a newly designed positron polarimeter.

    DOI

  • 早稲田大学におけるピコ秒パルスラジオリシスシステムの構築と改善

    小宮圭太, 永井宏幸, 野本知章, 丑田公規, 坂上和之, 神谷好郎, 柏木茂, 黒田隆之助, 濱義昌, 鷲尾方一

    放射線化学討論会講演要旨集   49th   133 - 134  2006

    J-GLOBAL

  • 高エネルギー重イオンビームによるフッ素系高分子材料への照射効果―2―

    大島明博, 三好のぞみ, 村田勝義, 三谷直弘, 松浦章雄, 坂上和之, 岡壽崇, 工藤久明, 加藤悦子, 村上健, 鷲尾方一, 濱義昌

    放射線化学討論会講演要旨集   49th   7 - 8  2006

    J-GLOBAL

  • Development of Pulse Laser Super-Cavity for compact high flux X-ray sources

    K. Sakaue, M. Washio, S. Araki, M. Fukuda, Y. Higashi, Y. Honda, M. Takano, T. Taniguchi, J. Urakawa, N. Sasao, H. Sakai

    EPAC 2006 - Contributions to the Proceedings     3155 - 3157  2006.01

     View Summary

    Pulsed Laser Super-Cavity has been developed for compact high brightness x-ray sources based on Laser Compton Scattering at KEK-ATF. The Pulse Laser Super-Cavity increases the laser power and stably makes small laser beam size at the collision point with the electron beam. Recent results of Super-Cavity and multi-bunch electron beam indicate the possibility of the application to K-edge digital subtraction angiography as the compact high flux X-ray source. Therefore, we have planned a compact hard xray source using 50MeV multi-bunch electrons and a pulse stacking technology with 42cm Fabry-Perot cavity. The photon flux is multiplied with the number of bunches by using multi-bunch beam and Super-Cavity. We have finished the constraction of 50MeV linac and started operation in spring 2006. Development of the Super-Cavity and plan of compact x-ray source will be presented at the conference.

  • Compact picosecond pulse radiolysis system using photo -cathode RF gun

    M. Washio, R. Moriyama, K. Sakaue, Y. Hama, Y. Kamiya, H. Nagai, M. Kawaguchi, H. Hayano, J. Urakawa, R. Kuroda, S. Kashiwagi, K. Ushida

    EPAC 2006 - Contributions to the Proceedings     2373 - 2375  2006.01

     View Summary

    High-tech research centre project, which was started in 1999, has been approved its second phase of research in 2004 from the government. In this project, we have installed high quality electron beam system based on the RF photo-cathode at Kikui-cho campus of Waseda University. In second phase of the project, improvement of beam quality and developments of applications using the system have been improved. Beam quality has been improved by modified injection of laser beam onto the photo-cathode and obtained about 3mmmrad with the beam charge of 100 pC. Using the system, we have performed picosecond pulse radiolysis experiments for the measurements of rise signal for hydrated electron at 720nm, which is the peak band of the species. Thus, we have obtained the time resolution of the experimental system to 16ps in FWHM.

  • Clic polarized positron source based on laser Compton scattering

    F. Zimmermann, H. Braun, M. Korostelev, L. Rinolfi, D. Schulte, E. Bulyak, P. Gladkikh, S. Araki, Y. Higashi, Y. Honda, Y. Kurihara, M. Kuriki, T. Okugi, T. Omori, T. Taniguchi, N. Terunuma, J. Urakawa, K. Moenig, A. Variola, F. Zomer, X. Artru, R. Chehab, M. Chevallier, V. Strakhovenko, J. Gao, S. Guiducci, P. Raimondi, V. Soskov, M. Fukuda, K. Hirano, M. Takano, T. Hirose, K. Sakaue, M. Washio, T. Takahashi, H. Sato, A. Tsunemi

    EPAC 2006 - Contributions to the Proceedings     2520 - 2522  2006.01

     View Summary

    We describe a possible layout and parameters of a polarized positron source for CLIC, where the positrons are produced from polarized gamma rays created by Compton scattering of a 1.3-GeV electron beam off a YAG laser. This scheme is very energy effective using high finesse laser cavities in conjunction with an electron storage ring. We point out the differences with respect to a similar system proposed for the ILC.

  • Development of high brightness soft x-ray source based on inverse Compton scattering

    R. Moriyama, K. Hidume, T. Saito, K. Sakaue, Y. Hama, A. Oshima, M. Washio, R. Kuroda, S. Kashiwagi, H. Hayano, J. Urakawa

    EPAC 2006 - Contributions to the Proceedings     166 - 168  2006

  • Development of a compact load lock system and a new tuning structurer for a Cs2Te cathode RF Gun

    Yoshio Kamiya, Y. Kamiya, M. Washio, Y. Hama, T. Hirose, K. Sakaue, A. Murata, J. Urakawa, T. Takatomi, N. Terunuma, M. Kuriki, N. Kudoh, R. Kuroda

    Annual Meeting of the Division of Particles and Fields of the American Physical Society, DPF 2006, and the Annual Fall Meeting of the Japan Particle Physics Community    2006.01

  • Beam diagnostics for high quality electron beam emitted from photocathode rf-gun

    Kazuyuki Sakaue, Norio Kudo, Ryo Moriyama, Masakazu Washio

    THIRD 21COE SYMPOSIUM: ASTROPHYSICS AS INTERDISCIPLINARY SCIENCE   31   229 - +  2006

     View Summary

    High quality electron beam generation using photocathode rf-gun system and beam diagnostic techniques have been developed at Waseda University. This system can generate up to 4.6 MeV low emittance and short bunch electron beam. For bunch length monitor, rf-kicker technique is able to streak the electron bunch directly, using transverse magnetic field on the beam orbit. This technique is able to observe the longitudinal profile of the bunch and to achieve higher resolution than streak camera method.

    DOI

  • High performance PI/PTFE layered films fabricated by EB irradiation

    Akihiro Oshima, Hiroyuki Nagai, Fumihiro Muto, Takaharu Miura, Masakazu Washio

    JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY   19 ( 1 ) 123 - 127  2006

     View Summary

    The fabrication of polytetrafluoroethylene (PTFE) and polyimide (PI) layered films has been demonstrated by high temperature soft electron beam (soft-EB) irradiation techniques. The PTFE dispersion has been coated by wire-bar coating, equipment oil PI thin film. The PI/PTFE layered films were irradiated by EB at 330 degrees C +/- 3 degrees C in nitrogen gas atmosphere. Characterization of soft-EB irradiated PI/PTFE films have been performed by X-ray photoelectron spectroscopy (XPS). thermal analysis (DSC and TGA). and so on. According to XPS analysis on PTFE coated side. the atom ratio of F/C, H/C and N/C were 2.44, 0.04 and 0.06, respectively. Thus, it was found the fluorine coated oil PI surface. that is. PTFE molecule has been reacted with PI polymer chains by high temperature soft-EB irradiation. Moreover the obtained hybrid films showed the good adhesive properties and lower crystallinity.

    DOI

  • Chemical crosslinking of polytetrafluoroethylene by fluorinated-pitch and its properties

    Akihiro Oshima, Masakazu Washio

    Polymer Preprints, Japan   55 ( 1 ) 188  2006

     View Summary

    Radiation-induced crosslinking of polytetrafluoroethylene [PIFE] has been established by the irradiation in its molten state under oxygen-free atmosphere. In this study, chemical crosslinking of PTFE has been demonstrated by using perfluoro-compound without any other catalyzed materials. Moreover, the characteristic properties of obtained materials have been measured by 19F NMR spectroscopy, DSC analysis and TGA. The obtained materials show the good mechanical properties and low crystallinty compared with PTFE. By DSC analysis, it is found that the obtained materials are crosslinked through thermal chemical reaction by radiacal formation through the decomposition of perfluoro-compound.

  • Development of PEM for PEFC consists of sulfonated FEP and Nafion® hybrid

    Yukiko Sato, Kazuki Fujii, Naohiro Mitani, Akio Matsuura, Tomoyuki Kakigi, Fumihiro Muto, Jingye Li, Akihiro Oshima, Masakazu Washio

    Polymer Preprints, Japan   55 ( 1 ) 1447  2006

     View Summary

    In this study, proton exchange membranes (PEMs) were fabricated by radiation-induced grafting of styrene onto FEP films and then sulfonated with chlorosulfonic acid. The hybrid PEMs were blended by Nafion and crushed sulfonated FEP fine powder. The properties of obtained PEMs were analyzed by thermal, electro-chemical measurements.

  • Direct etching process using focused ion beam for microfabrication of crosslinked PTFE

    Nozomi Miyoshi, Yoshinori Matsui, Akihiro Oshima, Shu Seki, Katsuyoshi Murata, Etsuko Kato, Seiichi Tagawa, Masakazu Washio

    Polymer Preprints, Japan   55 ( 2 ) 3314 - 3315  2006

     View Summary

    Micro structures of polytetrafluoroethylene (PTFE) and crosslinked PTFE (RX-PTFE), which has remarkable thermal stability, chemical stability and electrical insulation, have been processed by focused ion beam (FIB). Fine structures of radiation crosslinked PTFE (RX-PTFE),with the size of several tens of μm, have been fabricated by FIB maskless direct etching. PTFE and RX-PTFE with various crosslinking densities, which were controlled from 0.23 % to 1.2 %, were irradiated by 30 keV/ 2.9-12 nA Ga+ ion beam with the fluence of 0.3 × 1016 - 4.5 × 1016 ions/cm 2. It was found that the etching rate of PTFE and RX-PTFE was approximately 10-15 μm/(ion/cm2).

  • Beam diagnostics for laser undulator based on compton backward scattering

    R. Kuroda, K. Hidume, M. Kawaguchi, S. Minamiguchi, R. Moriyama, T. Saito, K. Sakaue, M. Washio, S. Kashiwagi, J. Urakawa, H. Hayano

    Proceedings of the 27th International Free Electron Laser Conference, FEL 2005     596 - 599  2005.12

     View Summary

    A low-emittance electron beam is required for the X-ray generation such as the synchrotron radiation and the laser undulator. The laser undulator based on Compton backward scattering has been developed as a compact soft X-ray source for the biological observation at Waseda University. To generate the soft X-ray pulse stably, beam diagnostics is very important. In case of the laser undulator, the energy of the electron beam can be lower than other X-ray source such as synchrotron radiation but it is difficult to measure the beam characteristics about the low energy electron beam like a 5 MeV due to the space charge effect. Consequently, the slit scan technique has been developed to measure the beam emittance precisely. In case of the photocathode rf gun, the beam emittance strongly depends on the laser injection method. To generate the low-emittance beam, the emittance comparison experiments have been performed among three deferent methods, the slanting injection (the standard injection), the slanting injection with profile shaping and the perpendicular injection using the slit scan technique. In this conference, we will report results of the experiments.

  • Design of a Polarised Positron Source Based on Laser Compton Scattering

    S. Araki, Y. Higashi, Y. Honda, Y. Kurihara, M. Kuriki, T. Okugi, T. Omori, T. Taniguchi, N. Terunuma, J. Urakawa, X. Artru, M. Chevallier, V. Strakhovenko, E. Bulyak, P. Gladkikh, K. Moenig, R. Chehab, A. Variola, F. Zomer, S. Guiducci, P. Raimondi, F. Zimmermann, K. Sakaue, T. Hirose, M. Washio, N. Sasao, H. Yokoyama, M. Fukuda, K. Hirano, M. Takano, T. Takahashi, H. Sato, A. Tsunemi, J. Gao, V. Soskov

       2005.09

    Internal/External technical report, pre-print, etc.  

     View Summary

    We describe a scheme for producing polarised positrons at the ILC from<br />
    polarised X-rays created by Compton scattering of a few-GeV electron beam off a<br />
    CO2 or YAG laser. This scheme is very energy effective using high finesse laser<br />
    cavities in conjunction with an electron storage ring.

  • Conceptual Design of a Polarised Positron Source Based on Laser Compton Scattering-A Proposal Submitted to Snowmass 2005-

    ARAKI Sakae, HIGASHI Yasuo, HONDA Yousuke, KURIHARA Yoshimasa, KURIKI Masao, OKUGI Toshiyuki, OMORI Tsunehiko, TANIGUCHI Takashi, TERUNUMA Nobuhiro, URAKAWA Junji, ARTRU X, CHEVALLIER M, STRAKHOVENKO V, BULYAK Eugene, GLADKIKH Peter, MOENIG Klaus, CHEHAB Robert, VARIOLA Alessandro, ZOMER Fabian, GUIDUCCI Susanna, RAIMONDI Pantaleo, ZIMMERMANN Frank, SAKAUE Kazuyuki, HIROSE Tachishige, WASHIO Masakazu, SASAO Noboru, YOKOYAMA Hirokazu, FUKUDA Masafumi, HIRANO Koichiro, TAKANO Mikio, TAKAHASHI Tohru, SATO Hiroki, TSUNEMI Akira, GAO Jie, SOSKOV Viktor

    KEK Prepr   ( 2005-60 ) 41P  2005.09

    J-GLOBAL

  • Fabrication of PEFC membrane based on PTFE/FEP polymer-alloy using radiation-grafting

    S Asano, F Mutou, S Ichizuri, JY Li, T Miura, A Oshima, Y Katsumura, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   236   437 - 442  2005.07

     View Summary

    Polymer electrolyte fuel cells (PEFC) membranes based on very thin film of network polytetrafluoroethylene (PTFE)/tetrafluoroethylene-co-hexafluoropropylene (FEP) polymer-alloy (PTFE/FEP polymer-alloy: FE), have been fabricated by radiation-grafting with reactive styrene monomers using electron beam irradiation (EB) under nitrogen atmosphere at room temperature. The characteristic properties of obtained materials have been measured by ion exchange capacity (IEC), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and so on. The grafting yields showed the initial rapid increase, and then tended to saturate above 5-8 h. The grafting yields of all FE with various network densities have been achieved 80-100%. The styrene-grafted materials were sulfonated by chlorosulfonic acid. The IECs of sulfonated materials based on FE polymer-alloy have been achieved 3.0 meq/g. This suggests that IEC value is independent on network density and PTFE/FEP blend ratio. The IEC values of obtained materials are about three times higher than those of commercial perfluoro-sulfonic acid (PFSA) membranes.
    By small angle X-ray scattering (SAXS), it is found that the higher network densities would give the smaller cluster sizes in sulfonated materials. Thus, the higher amount of FEP will give the smaller cluster formation of sulfonated materials. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

  • Development of compact picosecond pulse radiolysis system

    M Kawaguchi, K Ushida, S Kashiwagi, R Kuroda, T Kuribayashi, M Kobayashi, Y Hama, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   236   425 - 431  2005.07

     View Summary

    A pulse radiolysis technique is known as a powerful method to study the primary processes in radiation chemistry. However, a large-sized accelerator and a huge cost should be required for the construction and operation of pulse radiolysis system. Very recently, the new compact picosecond pulse radiolysis system composed of the small size accelerator and laser system has been developed at RISE, Waseda University. To evaluate the performance of the system, the absorption measurement of hydrated electrods was carried out as a preliminary experiment. As a result, the time resolution was estimated to be approximately 26 ps. It is analytically calculated to be approximately 30 ps (FWHM) with the convolution among the beam size, the bunch length of electron beam, the laser spot size, and the laser pulse length. The experimental value is in good agreement with the calculated one. The system has been developed to get better S/N ratio and will be applied for the study of primary processes in radiation chemistry of polymer system. (c) 2005 Elsevier B.V. All rights reserved.

    DOI

  • 早稲田大学フォトカソードRF電子銃ベースの電子源について

    森山亮, 坂上和之, 鷲尾方一, 黒田隆之助, 柏木茂, 早野仁司, 浦川順冶

    アイソトープ・放射線研究発表会要旨集   42nd   49  2005.06

    J-GLOBAL

  • イオン照射ポリエチレンの経時変化とその抑制

    岡壽崇, 本橋良太, 土谷忠義, 近藤光顕, 大島明博, 鷲尾方一, 岩田稔, 工藤久明, 勝村庸介, 伊藤賢志, 小林慶規, 村上健, 濱義昌

    放射線化学討論会講演要旨集   48th  2005

    J-GLOBAL

  • 24pXM-4 Soft X-ray generation via inverse Compton scattering and its application

    Minamiguchi Shuichi, Kashiwagi Shigeru, Ushida Kiminori, Hidume Kentaro, Saito Taku, Ueyama Daisuke, Kuroda Ryunosuke, Oshima Akihiro, Washio Masakazu, Urakawa Junji, Hayano Hitoshi

    Meeting Abstracts of the Physical Society of Japan   60 ( 0 ) 106 - 106  2005

    DOI CiNii

  • 早稲田大学におけるピコ秒パルスラジオリシスシステムの構築と改善

    川口昌朗, 丑田公規, 柏木茂, 黒田隆之助, 栗林剛彦, 鷲尾方一

    アイソトープ・放射線研究発表会要旨集   42nd  2005

    J-GLOBAL

  • 早稲田大学高品質電子ビーム発生装置の現状

    坂上和之, 樋爪健太郎, 斉藤卓, 川口昌朗, 森山亮, 南口修一, 永井宏幸, 鷲尾方一, 黒田隆之助, 柏木茂, 早野仁司, 浦川順治

    放射線化学討論会講演要旨集   48th   7 - 8  2005

    J-GLOBAL

  • 24aXM-3 Pulse Polarized Positron Generation at KEK ATF 1 : Development of inverse Compton scattering process for polarized positron generation

    Sakaue Kazuyuki, Fukuda Masafumi, Kuroda Ryunosuke, Saito Taku, Hirose Tachishige, Washio Masakazu, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kurihara Yoshimasa

    Meeting Abstracts of the Physical Society of Japan   60 ( 0 ) 104 - 104  2005

    CiNii

  • 24aXM-4 Pulse Polarized Positron Generation at KEK ATF 2 : Gamma Rays Generation for Pulse Polarized Positron Generation

    Saito Taku, Kuroda Ryunosuke, Sakaue Kazuyuki, Hirose Tachishige, Washio Masakazu, Urakawa Junji

    Meeting Abstracts of the Physical Society of Japan   60 ( 0 ) 104 - 104  2005

    CiNii

  • Detector concepts

    Gerald Aarons, Toshinori Abe, Jason Abernathy, Medina Ablikim, Halina Abramowicz, David Adey, Catherine Adloff, Chris Adolphsen, Konstantin Afanaciev, Ilya Agapov, Jung Keun Ahn, Hiroaki Aihara, Mitsuo Akemoto, Maria Del CarmenAlabau, Justin Albert, Hartwig Albrecht, Michael Albrecht, David Alesini, Gideon Alexander, Jim Alexander, Wade Allison, John Amann, Ramila Amirikas, Qi An, Shozo Anami, B. Ananthanarayan, Terry Anderson, Ladislav Andricek, Marc Anduze, Michael Anerella, Nikolai Anfimov, Deepa Angal-Kalinin, Sergei Antipov, Claire Antoine, Mayumi Aoki, Atsushi Aoza, Steve Aplin, Rob Appleby, Yasuo Arai, Sakae Araki, Tug Arkan, Ned Arnold, Ray Arnold, Richard Arnowitt, Xavier Artru, Kunal Arya, Alexander Aryshev, Eri Asakawa, Fred Asiri, David Asner, Muzaffer Atac, Grigor Atoian, David Attié, Jean Eudes Augustin, David B. Augustine, Bradley Ayres, Tariq Aziz, Derek Baars, Frederique Badaud, Nigel Baddams, Jonathan Bagger, Sha Bai, David Bailey, Ian R. Bailey, David Baker, Nikolai I. Balalykin, Juan Pablo Balbuena, Jean Luc Baldy, Markus Ball, Maurice Ball, Alessandro Ballestrero, Jamie Ballin, Charles Baltay, Philip Bambade, Syuichi Ban, Henry Band, Karl Bane, Bakul Banerjee, Serena Barbanotti, Daniele Barbareschi, Angela Barbaro-Galtieri, Desmond P. Barber, Mauricio Barbi, Dmitri Y. Bardin, Barry Barish, Timothy L. Barklow, Roger Barlow, Virgil E. Barnes, Maura Barone, Christoph Bartels, Valeria Bartsch, Rahul Basu, Marco Battaglia, Yuri Batygin, Jerome Baudot, Ulrich Baur, D. Elwyn Baynham, Carl Beard, Chris Bebek, Philip Bechtle

    LCWS 2005 - 2005 International Linear Collider Workshop    2005

  • Present status of photo-cathode RF gun system and its applications

    R Kuroda, Y Hama, K Hidume, M Kawaguchi, S Minamiguchi, R Moriyama, T Saito, K Sakaue, M Washio, S Kashiwagi, J Urakawa, H Hayano

    2005 IEEE PARTICLE ACCELERATOR CONFERENCE (PAC), VOLS 1-4   2005   53 - 55  2005

     View Summary

    High quality electron beam generation using photocathode rf gun system and its applications have been developed at Waseda University. This system can generate up to 4.6 MeV low emittance electron beam with bunch length of about 10 ps (FWHM). It is applied for soft Xray generation using laser Compton scattering and pulse radiolysis experiments based on the pump-probe technique. In the former, Compton scattering experiments between about 4.6 MeV electron beam and 1047 nm laser beam is performed at 20 degrees interaction angle, so that about 370 eV soft X-ray is generated. In the latter, the electron beam is used for the pump beam and the probe beam is generated as white light by concentrating laser beam on the water cell, so that the measurement with about 30 ps (FWHM) time resolution of the pulse radiolysis system is demonstrated for the absorption of hydrated electrons. In this conference, we will present the experimental results, status of this system and future applications.

    DOI

  • 固体NMR法による電子線照射メタロセン触媒ポリエチレン/ポリテトラフルオロエチレンポリマーブレンドの解析

    沼田ゆかり, 大島明博, 鷲尾方一, 加藤悦子

    高分子学会予稿集(CD-ROM)   53 ( 2 Disk1 ) 3PD064  2004.09

    J-GLOBAL

  • 28pSB-10 Simulation of Plasma Field Acceleration of 60MeV e-beam at BNL

    Ishimizu A, Kumita T, Kamiya Y, Hirose T, Washio M, Urakawa J, Omori T, Kurihara Y, Yokoya K, Ben-zvi I, Pogorelsky I V, Yakimenko V, Suk Hyyong, Lee Hae June, Zigler A

    Meeting abstracts of the Physical Society of Japan   59 ( 2 ) 15 - 15  2004.08

    CiNii

  • Toward the Bright Future of Japanese Society of Radiation Chemistry

    WASHIO Masakazu

      77   1 - 1  2004.03

    CiNii

  • X-Ray Generation Using Inverse Compton Scattering

    KURODA Ryunosuke, KASHIWAGI Shigeru, WASHIO Masakazu

      77   41 - 45  2004.03

    CiNii

  • 28aZS-7 Polarized positron generation by inverse compton Scattering 1 : Generate mechanism of polarized positron and measurement system

    Yamazaki Issei, Fukuda Masafumi, Hirose Tachishige, Kurihara Yoshimasa, Nomura Masahiro, Okugi Toshiyuki, Ohashi Ayumu, Omori Tsunehiko, Urakawa Junji, Washio Masakazu

    Meeting abstracts of the Physical Society of Japan   59 ( 1 ) 114 - 114  2004.03

    CiNii

  • 28aZS-8 Polarized positron genetation by inverse compton sattering 2 : measurement detector

    Ohashi Ayumu, Fukuda Masafumi, Hirose Tachishige, Kurihara Yoshimasa, Okugi Toshiyuki, Omori Tsunehiko, Urakawa Junji, Washio Masakazu, Nomura Masahiro, Yamazaki Issei

    Meeting abstracts of the Physical Society of Japan   59 ( 1 ) 115 - 115  2004.03

    CiNii

  • 28aZS-9 Polarized Positron Generation by Inverse Compton Scattering 3 : Results and Summary

    Fukuda Masafumi, Urakawa Junji, Ohashi Ayumu, Omori Tsunehiko, Okugi Toshiyuki, Kurihara Yoshimasa, Nomura Masahiro, Hirose Tachishige, Yamazaki Issei, Washio Masakazu

    Meeting abstracts of the Physical Society of Japan   59 ( 1 ) 115 - 115  2004.03

    CiNii

  • 28aZS-11 Simulation of electron-laser beam interactions in plasma channels

    Kumita T, Ishimizu A, Kamiya Y, Hirose T, Washio M, Urakawa J, Omori T, Kurihara Y, Yokoya K, Ben-zvi I, Pogorelsky I.V, Yakumenko V, Suk H.Y, Lee H.J, Zigler A

    Meeting abstracts of the Physical Society of Japan   59 ( 1 ) 115 - 115  2004.03

    CiNii

  • 28aZS-10 Nonlinear Compton Experiment at the BNL-ATF

    Kamiya Yoshio, Ishimizu Akio, Kumita Tetsuro, Hirose Tachishige, Washio Masakazu, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kurihara Yoshimasa, Yokoya Kaoru, Ben-Zvi I, Pogorelsky I.V., Siddons D.P., Yakimenko V.

    Meeting abstracts of the Physical Society of Japan   59 ( 1 ) 115 - 115  2004.03

    CiNii

  • Application of electron beams for the treatment of VOC streams

    K Hirota, H Sakai, M Washio, T Kojima

    INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH   43 ( 5 ) 1185 - 1191  2004.03

     View Summary

    Electron-beam technology is based on using radical reactions to destroy air pollutants. Twenty volatile organic compounds (VOCs) were irradiated with electron beams in a laboratory-scale apparatus to examine the influence of the chemical structures of the VOCs from an energetic point of view. The experiments showed that the electron-beam energy required for 90% treatment could be roughly estimated from their chemical structures. The unification of a self-shielding electron accelerator with a reactor could reduce capital costs for electron-beam systems. Electron-beam technology is a promising method for the treatment of VOCs.

    DOI

  • 28aZS-6 Development of Soft X-ray Source using Laser Compton Scattering

    Kuroda Ryunosuke, Kashiwagi Shigeru, Nagasawa Fumio, Ueyama Daisuke, Hidume Kentarou, Washio Masakazu, Ushida Kiminori, Hayano Hitoshi, Urakawa Junji

    Meeting Abstracts of the Physical Society of Japan   59 ( 0 ) 114 - 114  2004

    DOI CiNii

  • 早稲田大学におけるピコ秒パルスラジオリシスシステムの構築

    川口昌朗, 丑田公規, 柏木茂, 黒田隆之助, 小林雅貴, 栗林剛彦, 鷲尾方一

    理工学における同位元素・放射線研究発表会要旨集   41st  2004

    J-GLOBAL

  • 早大ピコ秒RF電子銃を用いたパルスラジオリシスのシステム開発(2)

    栗林剛彦, 丑田公規, 柏木茂, 黒田隆之助, 川口昌朗, 小林雅貴, 濱 義昌, 鷲尾 方一

    第47回放射線化学討論会,2004.10.9-11,北大    2004

  • 27aZR-4 Beam Diagnostics for RF-Gun System at Waseda University

    Sakaue Kazuyuki, Kuroda Ryunosuke, Kawai Hiraku, Kudo Norio, Washio Masakazu, Kashiwagi Shigeru, Hayano Hitoshi, Urakawa Junji

    Meeting Abstracts of the Physical Society of Japan   59 ( 0 ) 104 - 104  2004

    CiNii

  • X-ray spectrometer for observation of nonlinear Compton scattering

    Y Kamiya, T Kumita, DP Siddons, Ben-Zvi, I, C Liu, AT Macrander, T Hirose, M Washio, T Omori, J Urakawa, K Yokoya

    QUANTUM ASPECTS OF BEAM PHYSICS     103 - 110  2004

     View Summary

    An x-ray spectrometer, which consists of a multilayer device and a two-dimensional position sensitive detector, is designed for measurement of the x-ray energy spectrum and angular distribution from the nonlinear Compton scattering of 60 MeV electron and high power CO2 laser beams provided by a user facility at Brookhaven National Laboratory. A Prototype of the spectrometer has constructed and tested using isotropic 8 keV (Cu K alpha) x-rays from a seated x-ray tube.

    DOI

  • Production of a short-bunch polarized positron beam and design of a positron polarimeter

    M Fukuda, A Ohashi, T Hirose, M Washio, Yamazaki, I, Y Kurihara, M Nomura, T Okugi, T Omori, J Urakawa

    QUANTUM ASPECTS OF BEAM PHYSICS     95 - 102  2004

     View Summary

    We have been pursuing a basic study of a polarized positron source for a next generation linear collider, JLC based on two fundamental processes, i.e. inverse Compton scattering of circularly polarized laser-photons and pair-creation of a polarized gamma-ray. Polarized gamma-rays were produced at; collisions of circularly polarized laser-beams with a wave length of 532nm provided from a Nd:YAG with counter-propagating electron beams of 1.28 GeV. Since a time-duration of produced gamma-rays is extremely short, i.e. 30 ps, we have developed a transmission method in which a total flux of gamma-rays passing through magnetized iron is measured resulting in asymmetry determination. We will report technical details of a positron polarimetry, which will be soon employed to substantiate our proposed view concerning a JLC polarized positron source.

    DOI

  • Study of laser Compton scattering in a plasma channel

    T Kumita, Y Kamiya, Ben-Zvi, I, K Kusche, Pogorelsky, IV, Yakimenko, V, DP Siddons, T Hirose, S Kashiwagi, M Washio, D Cline, F Zhou, D Kaganovich, A Zigler

    QUANTUM ASPECTS OF BEAM PHYSICS     80 - 85  2004

     View Summary

    Compton scattering of laser and electron beams in a plasma channel can be utilized for high intensity X-ray source and polarized positron source for future linear colliders. Transportation of a CO2 laser beam by a 17mm plasma channel was observed. An X-ray generation experiment via laser Compton scattering in the plasma channel was attempted but the signal could not be separated from the background because of the electron beam modulation by the plasma.

    DOI

  • Extreme expansion of proximity gap by double exposures using enlarged pattern masks for line and space pattern formation in x-ray lithography (evolution of exposure method to symmetric illumination)

    E Toyota, M Washio, H Watanabe, H Sumitani

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B   21 ( 6 ) 2821 - 2825  2003.11

     View Summary

    The extendibility of x-ray lithography is limited by the usable proximity gap. The gap is considered to be larger than 10 mum. Practically, a line and space (L/S) pattern of 70 nm linewidth and 140 nm pitch can be formed at a 10 Am gap using a 1:1 exposure mask (1X mask). If a double-pitch mask (2 X mask), whose LIS pitch is twice as large as desired what to be printed on the wafer, is used while applying double exposures, the gap can be expanded greatly. A simulation result showed that using a 2X mask, a gap of more than 1000 mum can be used to form a L/S pattern of 200 nm pitch. An exposure test at a gap of 160 mum using the 2X mask proved sufficient to form the L/S pattern of 200 nm pitch. The principle of symmetric illumination explains this result well. The principle is also applicable to two-dimensional pattern formation, for which we propose a concept of mask design, i.e., the symmetric-illumination mask (SIM). Multidot images formed by the SIMs can produce mega- or giga-unit patterns of less than 25 nm linewidth by applying continuous writing. (C) 2003 American Vacuum Society.

    DOI

  • Polarimetry of short-pulse gamma rays produced through inverse compton scattering of circularly polarized laser beams

    M Fukuda, T Aoki, K Dobashi, T Hirose, T Iimura, Y Kurihara, T Okugi, T Omori, Sakai, I, J Urakawa, M Washio

    PHYSICAL REVIEW LETTERS   91 ( 16 )  2003.10

     View Summary

    We have developed a polarimetry of ultrashort pulse gamma rays based on the fact that gamma rays penetrating in the forward direction through a magnetized iron carry information on the helicity of the original gamma rays. Polarized, short-pulse gamma rays of (1.1+/-0.2)x10(6)/bunch with a time duration of 31 ps and a maximum energy of 55.9 MeV were produced via Compton scattering of a circularly polarized laser beam of 532 nm off an electron beam of 1.28 GeV. The first demonstration of asymmetry measurements of short-pulse gamma rays was conducted using longitudinally magnetized iron of 15 cm length. It is found that the gamma-ray intensity is in good agreement with the simulated value of 1.0x10(6). Varying the degree of laser polarization, the asymmetry for 100% laser polarization was derived to be (1.29+/-0.12)%, which is also consistent with the expected value of 1.3%.

    DOI

  • 早稲田大学における4MeV光電子ビームエミッタンス測定

    川合啓, 工藤経生, 黒田隆之助, 坂上和之, 浜義昌, 鷲尾方一, 柏木茂, 浦川順治, 早野仁司

    放射線化学討論会講演要旨集   46th   44 - 45  2003.09

    J-GLOBAL

  • Synchrotron Radiation Induced Direct Photo-Etching and Surface Modification of PTFE

    OSHIMA Akihiro, WASHIO Masakazu

      76   3 - 9  2003.09

    CiNii

  • Surface modification of polytetrafluoroethylene by synchrotron radiation

    Y Sato, D Yamaguchi, T Katoh, S Ikeda, Y Aoki, A Oshima, Y Tabata, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS   208   231 - 235  2003.08

     View Summary

    Surface modification of polytetrafluoroethylene (PTFE) films by the irradiation using synchrotron radiation (SR) below the melting temperature was studied. The changes in chemical structures, surface compositions and thermal properties of the SR-irradiated PTFE were examined by solid-state F-19 NMR, X-ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC), respectively. In order to investigate the degree of modification as a function of depth from the irradiated surface, some PTFE thin films were stacked in layers under vacuum and then they were irradiated with SR. It was found that crosslinking reaction was induced by SR-irradiation in the solid-state within 50 mum from the exposed surface and chain scission was dominant at deeper layers. (C) 2003 Elsevier B,V. All rights reserved.

    DOI

  • Erratum: Design of a polarized positron source for linear colliders (Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated PII: S016890020201985X)

    T. Omori, T. Aoki, K. Dobashi, T. Hirose, Y. Kurihara, T. Okugi, I. Sakai, A. Tsunemi, J. Urakawa, M. Washio, K. Yokoya

    Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   503 ( 3 ) 658  2003.05

    DOI

  • Emittance measurement of the 4MeV photo electron beam using slit-scan technique

    Kawai Hiraku, Kashiwagi Shigeru, Kuroda Ryunosuke, Kudo Norio, Hama Yoshimasa, Washio Masakazu, Urakawa Junji, Hayano Hitoshi

    Meeting abstracts of the Physical Society of Japan   58 ( 1 ) 124 - 124  2003.03

    CiNii

  • Polarized Positron Source for LC 2 : Development of a positron polarimeter

    Fukuda Masafumi, Hirose Tachishige, Kurihara Yoshimasa, Okugi Toshiyuki, Ohashi Ayumu, Omori Tsunehiko, Urakawa Junji, Washio Masakazu, Yamazaki Issei

    Meeting abstracts of the Physical Society of Japan   58 ( 1 ) 108 - 108  2003.03

    CiNii

  • Polarized Positron Source for LC 4 : Pressurized Cherenkov Counter

    Ohashi Ayumu, Fukuda Masafumi, Hirose Tachishige, Kurihara Yoshimasa, Okugi Toshiyuki, Omori Tsunehiko, Urakawa Junji, Washio Masakazu, Yamazaki Issei

    Meeting abstracts of the Physical Society of Japan   58 ( 1 ) 108 - 108  2003.03

    CiNii

  • Polarized Positron Source for LC 1 : Present status and future prospects

    Hirose Tachishige, Urakawa Junji, Ohashi Ayumu, Omori Tsunehiko, Okugi Toshiyuki, Kashiwagi Shigeru, Kamiya Yoshio, Kumita Tetsuro, Kurihara Yoshimasa, Fukuda Masafumi, Yamazaki Issei, Yokoya Kaoru, Washio Masakazu

    Meeting abstracts of the Physical Society of Japan   58 ( 1 ) 107 - 107  2003.03

    CiNii

  • Visible Radiation from a Photonic Crystal Induced by Electron Beams

    Ishimaru T., Adachi M., Saito N., Ogata A., Kozawa T., Yoshida Y., Tagawa S., Wasio M., Kashiwagi S., Kuroda R.

    Meeting abstracts of the Physical Society of Japan   58 ( 1 ) 110 - 110  2003.03

    CiNii

  • Polarized Positron Source for LC 6 : Nonlinear Thomson Scattering (experiment)

    Kamiya Yoshio, Kumita Tetsuro, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kurihara Yoshimasa, Yokoya Kaoru, Hirose Tachishige, Washio Masakazu, Ilan Ben Zvi, Kusche Karl, Pogorelsky Igor, Siddons Peter, Yakimenko Vitaly

    Meeting abstracts of the Physical Society of Japan   58 ( 1 ) 109 - 109  2003.03

    CiNii

  • Polarized Positron Source for LC 3 : Design of a electromagnet for polarization measurement

    Yamazaki Issei, Fukuda Masafumi, Hirose Tachishige, Kurihara Yoshimasa, Okugi Toshiyuki, Ohashi Ayumu, Omori Tsunehiko, Urakawa Junji, Washio Masakazu

    Meeting abstracts of the Physical Society of Japan   58 ( 1 ) 108 - 108  2003.03

    CiNii

  • Polarized Positron Source for LC 5 : Thomson Scattering in a Plasma Channel

    Kumita Tetsuro, Kamiya Yoshio, Urakawa Junji, Omori Tsunehiko, Okugi Toshiyuki, Kurihara Yoshimasa, Yokoya Kaoru, Hirose Tachishige, Washio Masakazu, Ilan Ben Zvi, Kusche Karl, Pogoreisky Igor, Siddons Peter, Yakimenko Vitaly

    Meeting abstracts of the Physical Society of Japan   58 ( 1 ) 108 - 108  2003.03

    CiNii

  • Design of a polarized positron source for linear colliders

    T Omori, T Aoki, K Dobashi, T Hirose, Y Kurihara, T Okugi, Sakai, I, A Tsunemi, J Urakawa, M Washio, K Yokoya

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   500 ( 1-3 ) 232 - 252  2003.03

     View Summary

    We propose a design of a polarized positron source for linear colliders. The design is based on electron-positron pair creation from polarized gamma-rays which are produced by Compton scattering of circularly polarized laser light off a high-energy electron beam. Polarized positrons are created from those gamma-rays incident on a thin conversion target. A future linear collider of the TeV-energy region requires an extraordinary large number of positrons (similar to 1 x 10(10) positrons/ bunch) in a multi-bunch time structure. To meet these requirements, our design employs a high-current, low-emittance electron beam of 5.8 GeV, 10 CO2 lasers, and 200 laser-electron collision-points. At each collision point, a pair of specially designed parabolic mirrors is installed to achieve efficient head-on collisions. This system allows us to produce high-intensity polarized gamma-rays, which effectively generate high-intensity polarized positrons with the magnitude of polarization greater than 50%. (C) 2003 Elsevier Science B.V. All rights reserved.

    DOI

  • 31pSH-1 レーザーコンプトン散乱を用いた『水の窓』領域軟 X 線源の開発

    黒田 隆之助, 丑田 公規, 長澤 章雄, 上山 大輔, 柏木 茂, 広瀬 立成, 鷲尾 方一, 濱 義昌, 浦川 順治, 早野 仁司

    日本物理学会講演概要集   58 ( 0 ) 126 - 126  2003

    DOI CiNii

  • 早大ピコ秒RF電子銃を用いたパルスラジオリシスシステムの開発

    小林雅貴, 丑田公規, 青木康, 栗林剛彦, 川口昌朗, 柏木茂, 黒田隆之助, 浜義昌, 鷲尾方一

    放射線化学討論会講演要旨集   46th  2003

    J-GLOBAL

  • フォトカソードRFガンを用いたパルスラジオリシスのシステム構築

    栗林剛彦, 丑田公規, 柏木茂, 黒田隆之助, 小林雅貴, 鷲尾方一

    理工学における同位元素・放射線研究発表会要旨集   40th  2003

    J-GLOBAL

  • レーザーコンプトン散乱を用いた小型軟X線源の開発

    長沢章雄, 上山大輔, 柏木茂, 黒田隆之助, 鷲尾方一, 丑田公規, 早野仁司, 浦川順治

    放射線化学討論会講演要旨集   46th  2003

    J-GLOBAL

  • High-aspect ratio microfabrication of crosslinked polytetrafluoroethylene using synchrotron radiation direct photo-etching

    T Katoh, Y Sato, D Yamaguchi, S Ikeda, Y Aoki, A Oshima, M Washio, Y Tabata

    MICROMACHINING AND MICROFABRICATION PROCESS TECHNOLOGY VIII   4979   493 - 500  2003

     View Summary

    High-aspect ratio micro-fabrication of crosslinked polytetrafluoroethylene (PTFE) has been carried out using synchrotron radiation (SR) direct photo-etching. The etching rates of crosslinked PTFE samples with various crosslinked densities were studied by changing photon fluence of SR at different sample temperatures. The maximum etching rate of 150 micron/min was achieved at SR beam current of 600 mA. The etching rate of the sample with higher crosslinking density resulted in a higher etching rate. This rate was about two times higher than that of non-crosslinked PTFE. The effects of molecular motion and fragmentation of the molecules on etching process were discussed from temperature dependence on etching rate. Furthermore, we have found that surface modification of non-crosslinked PTFE had been proceeding during irradiation of SR to the surfaces at 140 degreesC. The modified surfaces were examined on behavior of crystallites by differential scanning calorimetry, and on chemical structure by FTIR spectroscopy and solid-state F-19 NMR spectroscopy. The results showed that properties of modified layers have dependence on depth. Crosslinking reaction would be. induced by SR irradiation even in its solid state within about 50 mum from the surface.

    DOI

  • Thermal distortion of wavefront in high-intensity-laser system for inverse Compton X-ray generation

    H Ishikawa, SJ Ito, A Endo, T Yanagida, K Torizuka, F Sakai, M Washio

    LASER RESONATORS AND BEAM CONTROL VI   4969   50 - 57  2003

     View Summary

    We have developed a. stable 7 terawatt (TW) (168 mJ per pulse, 24 fs pulse duration) Ti: sapphire laser system operating at 50 Hz for a generation of femtosecond X-ray pulses by inverse Compton scattering. We corrected the wavefront distortion of these high intensity laser pulses with adaptive optics using a Shack-Hartmann type wavefront sensor and a deformable mirror. We have also started developing a compact all-solid-state Yb: Sr-5(PO4)(3)F (Yb: S-FAP) laser system to realize a practical, X-ray pulse generation system. We measured thermal lensing induced in Yb: S-FAP crystal for design of a high-energy regenerative amplifier. In addition, we measured wavefront of the amplified pulses in the Yb: S-FAP regenerative amplifier with the wavefront sensor.

    DOI

  • Production of high brightness γ rays through backscattering of laser photons on high-energy electrons

    I. Sakai, T. Aoki, K. Dobashi, M. Fukuda, A. Higurashi, T. Hirose, T. Iimura, Y. Kurihara, T. Okugi, T. Omori, J. Urakawa, M. Washio, K. Yokoya

    Physical Review Special Topics - Accelerators and Beams   6 ( 9 ) 12 - 25  2003

     View Summary

    Based on the requirements from a conceptual design of a polarized positron beam for future linear colliders, we constructed a special collision system with a short focal length of 150 mm of the laser beams so as to produce γ rays through inverse Compton scattering. In order to achieve efficient laser-electron collisions, we created a special optics to produce very small e --beam sizes of σ ex0 = 7.6 μm and σ ey0 = 5.4 μm in the horizontal and vertical directions at the collision point. Using laser light with a wavelength of 532 nm and an e - beam of 1.28 GeV provided from the ATF-damping ring at KEK, we generated 2 × 10 5 γ rays with a time duration of 26 ps in rms, leading to a peak brightness of 1.7 × 10 18/(mrad 2mm 20.1%bandwidth s) near to the maximum energy of 56 MeV. © 2003 The American Physical Society.

    DOI

  • 解説 逆コンプトン散乱X線源 (特集 X線源の新潮流とX線画像技術)

    柏木 茂, 鷲尾 方一

    日本写真学会誌   65 ( 7 ) 463 - 467  2002.12

    CiNii

  • Low-emittance electron-beam generation with laser pulse shaping in photocathode radio-frequency gun

    J Yang, F Sakai, T Yanagida, M Yorozu, Y Okada, K Takasago, A Endo, A Yada, M Washio

    JOURNAL OF APPLIED PHYSICS   92 ( 3 ) 1608 - 1612  2002.08

     View Summary

    A technique of laser-pulse shaping was developed for low-emittance electron-beam generation in a photocathode radio-frequency (rf) gun. The emittance growth due to space charge and rf effects in the rf gun was experimentally investigated with square and gaussian temporal pulse shapes. It was found that the square pulse shaping was a useful tool for both the reduction of nonlinear space-charge force and the correction of linear space charge. The normalized transverse rms emittance at 1 nC was obtained to be 1.20 pimm-mrad for the square pulse shape with pulse length of 9 ps full width at half maximum. The emittance was measured as a function of the electron bunch charge and the laser-pulse length. (C) 2002 American Institute of Physics.

    DOI

  • Active synchronization of two mode-locked lasers with optical cross correlation

    T Miura, H Nagaoka, K Takasago, K Kobayashi, A Endo, K Torizuka, M Washio, F Kannari

    APPLIED PHYSICS B-LASERS AND OPTICS   75 ( 1 ) 19 - 23  2002.07

     View Summary

    Two mode-locked Ti:sapphire lasers of different wavelengths were precisely synchronized by a simple feedback system employing sum-frequency generation (cross correlation). When the timing error exceeded the pulse duration, the periodic bunch of the sum-frequency pulse was used for rough timing adjustment. Using cross correlation with a stretched pulse, we struck a balance between wide locking range and sensitive timing detection. When the two lasers were well-synchronized, we obtained a continuous cross-correlation pulse train for 3 min. The holding time of the laser synchronization was extended to over one hour by adding a motorized stage to the PZT-mounted cavity mirror. We estimated the rms timing jitter between the two lasers by a scanning cross-correlation measurement. We confirmed that the rms timing jitter of the two lasers during 1.8 s was 28 fs.

    DOI

  • Time bunching of slow positrons for lifetime and time-of-flight measurements of ortho-positronium

    H Iijima, T Asonuma, T Hirose, M Irako, K Kadoya, T Kumita, B Matsumoto, K Wada, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   483 ( 3 ) 641 - 648  2002.05

     View Summary

    On the basis of velocity modulation, we have developed a positron-beam buncher for the measurement of ortho-positronium lifetimer tau(o)-p(s) and TOF. Since high permeability cores were used, the buncher was constructed compactly and was used to efficiently produce a bunched beam with a bunch width of 2.2 ns (FWHM) and a repetition period of 960 ns. We have measured the lifetime of ortho-positronium using the buncher and obtained tau(o)-p(s) = 127 ns. In this paper, we report on the technical details and performance of the buncher. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI

  • 24aYA-6 プラズマチャンネルを用いたCO^2レーザーのCompton散乱実験

    神谷 好郎, 広瀬 立成, 汲田 哲郎, 浦川 順治, 横谷 馨, 大森 恒彦, 柏木 茂, 鷲尾 方一, Igor Pogorelsky, Iian Ben-Zvi, Karl Kucshe, Vitaly Yakimenko

    日本物理学会講演概要集   57 ( 1 ) 89 - 89  2002.03

    CiNii

  • 25aYA-13 東大ライナック・Mg photocathode RF gunの開発と現状

    飯島 北斗, 上坂 充, 上田 徹, 浦川 順治, 熊谷 教孝, 栗木 雅夫, 土橋 克広, 深澤 篤, 室屋 裕佐, 吉井 康司, 鷲尾 方一

    日本物理学会講演概要集   57 ( 1 ) 90 - 90  2002.03

    CiNii

  • 早大ピコ秒RF電子銃を用いたパルスラジオリシスシステムの開発

    小林雅貴, 丑田公規, 青木康, 森雅和, 栗林剛彦, 柏木茂, 黒田隆之助, 浜義昌, 鷲尾方一

    放射線化学討論会講演要旨集   45th  2002

    J-GLOBAL

  • Production of picosecond square-shaped ultraviolet pulses for low-emittance electron bunch generation from an RF photocathode

    A Yada, K Takasago, SJ Ito, T Yanagida, JF Yang, M Washio, K Torizuka, A Endo

    LASER RESONATORS AND BEAM CONTROL V   4629   213 - 221  2002

     View Summary

    We demonstrated generation of square-shaped ultraviolet pulses and that they reduces the emittance of electron beams from laser-photocathode RF-gun. Some frequency components of femtosecond pulses from a Ti:sapphire oscillator are modulated with a pulse shaper that consists of a lens pair, gratings, and a liquid crystal spatial light modulator (LC-SLM) to generate square-shaped pulses. The shaped pulses were amplified up to 3 mJ through a regenerative amplifier, and were converted to ultraviolet region with two different nonlinear crystals. Energy of the shaped pulses was about 100 muJ which is sufficient to generate electron charge of 1 nC. In our experiment, emittance of electron beam was reduced to as low as almost the half of that with non-shaped pulses.

    DOI

  • Generation of amplified picosecond square shaped pulses in ultraviolet region for an RF photocathode

    Kazuya Takasago, Akira Endo, Akira Yada, Masakazu Washio, Kenji Torizuka

    Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest     339  2002.01

     View Summary

    The generation of amplified picosecond square shaped pulses in ultraviolet region for an RF photocathode was described. The spectral phase reconstructed from the experimental interferogram of the shaped pulse and the unshaped pulse was measured as a function of spatial solution. It was shown that the emittance of the electron beam by using square shaped pulse was two times lower than the value by using a gaussian shaped pulse.

  • Microfabrication of crosslinked polytetrafluoroethylene using synchrotron radiation direct photo-etching

    T Katoh, D Yamaguchi, Y Satoh, S Ikeda, Y Aoki, M Washio, Y Tabata

    APPLIED SURFACE SCIENCE   186 ( 1-4 ) 24 - 28  2002.01

     View Summary

    High aspect-ratio (more than 10) microfabrication of crosslinked polytetrafluoroethylene (PTFE) has been carried out using synchrotron radiation (SR) direct photo-etching, The etching rates of crosslinked PTFE samples with various crosslinked densities were studied by changing photon fluence of SR at different sample temperatures, The etching rate of the sample with W-her crosslinking density resulted in a higher etching rate. This rate was about two times higher than that of normal PTFE. The temperature dependence of the etching rates indicated that molecular motion of alpha-relaxation of samples and structures of smaller fragments (i.e., etched products) produced by irradiation of SR with high dose rate play an important role for SR direct photo-etching. Moreover, we have found that surface modification of PTFE had been proceeding during irradiation of SR to the PTFE at 140 degreesC. The results of differential scanning calorimeter measurements for the modified layers showed that the layers might have crosslinking character. (C) 2002 Elsevier Science B.V. All rights reserved.

    DOI

  • Micromachining of crosslinked PTFE by direct photo-etching using synchrotron radiation

    Daichi Yamaguchi, Takanori Katoh, Yasunori Sato, Shigetoshi Ikeda, Masaoki Hirose, Yasushi Aoki, Minoru Iida, Akihiro Oshima, Yoneho Tabata, Masakazu Washio

    Macromolecular Symposia   181   201 - 212  2002

     View Summary

    Micromachining of crosslinked PTFE (polytetrafluoroethylene) using synchrotron radiation direct photo-etching method has been demonstrated. High aspect-ratio microfabrication was carried out. The etching rate of crosslinked PTFE was higher than that of non-crosslinked PTFE. Through the etching rate measurements of various samples, it was found that synchrotron radiation etching rate of crosslinked PTFE only depends on the degree of crosslinking, neither molecular weight nor crystallinity. The effect of molecular motion on etching process was discussed from temperature dependence data on etching rate. Furthermore, the surface region of synchrotron radiation irradiated sample was investigated by Fourier transform infrared spectroscopy and the experimental result showed that the modification induced by synchrotron radiation proceeded before desorption.

    DOI

  • Measurement of beam characteristics for photo-electron beam at Waseda University

    R. Kuroda, M. Washio, S. Kashiwagi, T. Oshima, J. Urakawa, H. Hayano, X. J. Wang

    Proceedings of the IEEE Particle Accelerator Conference   3   2275 - 2277  2001.12

     View Summary

    The low emittance and short pulse electron beam is expected to be used in a wide field, such as X-ray generation by inverse Compton scattering, pulse radiolysis, etc. The laser driven photo cathode rf gun system is possible to produce the low emittance and short pulse electron beam. It is very important for generating the low emittance and short pulse electron beam to measure the beam characteristics such as the bunch length precisely. In this report, the measurement system of the bunch length using frequency analysis for the photoelectron beam generated by the rf gun and results of the preliminary experiment at KEK-ATF (Accelerator Test Facility) injector linac is described.

  • Present status of rf gun project at Waseda University

    M. Washio, S. Kashiwagi, R. Kuroda, T. Oshima, Y. Hama, J. Urakawa, X. J. Wang

    Proceedings of the IEEE Particle Accelerator Conference   3   2290 - 2292  2001.12

     View Summary

    We have conducted the research project named &quot;High-Tech Research Center Project&quot; at Waseda University, which is supported by the Ministry of Education, Culture, Sports, Science and Technology. In this project, a laser photo-cathode rf-gun with 1.6 acceleration cells with Mg cathode has been installed for production of low emittance and short bunched electron beam. Main parts of rf source for the rf-gun consists of 10 MW s-band klystron and a small pulse modulator. The pulse modulator has good stability and flatness of the output pulse. The amplitude jitter of klystron voltage was realized down to 0.38 % (p-p) for 20000 pulses and the pulse flatness down to 0.25 % (within &gt;1.5 μs pulse flat-top). High quality electron beam is very powerful tool for the study on radiation physics, radiation chemistry, material science, etc. Development of short X-ray pulse generation by the inverse Compton scattering between high quality electron beam and laser light, will be started in 2001 fiscal year. The system will be applied to the pulse radiolysis experiments for the studies on radiation physics and chemistry.

  • All-solid-state picosecond laser system for photo cathode rf-gun and X-ray generation at Waseda University

    T. Oshima, Y. Hama, H. Ishikawa, S. Kashiwagi, R. Kuroda, M. Washio, A. Yada, H. Hayano, J. Urakawa

    Proceedings of the IEEE Particle Accelerator Conference   3   2400 - 2402  2001.12

     View Summary

    An 1.6 cell rf-gun system has been installed at Waseda University for the generation of high charge, short pulse and low emittance electron beam. The gun is one of essential component for X-ray generation using inverse Compton scattering between photo electron bunch and laser pulse. An all-solid-state picosecond Nd:YLF laser system has been installed at Waseda University and will be used not only for photo electron generation in the rf-gun but also for collision with the photo electron bunch. The laser system has the frequency conversion section, which is operated to produce the UV (262 nm) using BBO crystals from the amplified fundamental (1047 nm). Extremely stable laser system is required for the generation of high quality electron beam, and the system is essential component for the generation of X-rays through the inverse Compton scattering. Timing and intensity stabilities of laser pulse have been measured using time domain demodulation technique. As the results, timing stability of 0.26 ps against to the local oscillator of rf and intensity stability of 0.11% have been achieved. We have carried out the numerical simulation to calculate the number of photons and the energies of X-rays by changing the crossing angles.

  • Generation of high intensity X-rays via Compton soattering between electron and laser beams

    Kamiya Yoshio, Hirose Tachishige, Kumita Tetsuro, Urakawa Junji, Yokoya Kaoru, Omori Tsunehiko, Kashiwagi Shigeru, Washio Masakazu, Pogorelsky Igor, Ben-Zvi Ilan, Kusche Karl, Yakimenko Vitaly

    Meeting abstracts of the Physical Society of Japan   56 ( 2 ) 16 - 16  2001.09

    CiNii

  • Radiation Physics and Chemistry: Preface

    M. Washio, Y. Katsumura, N. Getoff

    Radiation Physics and Chemistry   60   245 - 246  2001.04

    DOI

  • Inspection of non-linear effect in laser-beam scattering

    Kamiya Yoshio, Hirose Tachishige, Kumita Tetsuro, Urakawa Junji, Yokoya Kaoru, Omori Tsunehiko, Kashiwagi Shigeru, Washio Masakazu, Iorl Pogorelsky, Ilan Ben-Zvi, Karl Kusche, Vitaly Yakimenko

    Meeting abstracts of the Physical Society of Japan   56 ( 1 ) 144 - 144  2001.03

    CiNii

  • International Symposium on Prospects for Application of Radiation Towards the 21st Century - 13-17 March 2000, Tokyo, Japan - Preface

    M Washio, Y Katsumura, N Getoff

    RADIATION PHYSICS AND CHEMISTRY   60 ( 4-5 ) 245 - 246  2001.03

    Other  

  • Image formation by continuous writing with multi-beam in x-ray nanolithography

    E Toyota, M Washio

    MICROPROCESSES AND NANOTECHNOLOGY 2001, DIGEST OF PAPERS     140 - 141  2001

     View Summary

    © 2001 Japan Soc. Of Applied Physics. Summary form only given. Difficulties in X-ray lithography are now condensed into mask related matters. Since the exposure mode is basically 1:1, more strict accuracy is requested for mask fabrication than for the final images. Mask fabrication technology has made remarkable progress, and image formation of 70 nm line width was reported recently (Miyatake et al, 2001). Meanwhile, pattern reduction necessitates narrowing gaps between mask and wafer, since the gaps decrease in proportion to the square of the line width. If we want to form 25-35 nm two-dimensional patterns in future, mask-wafer gaps of 2-4 μm are needed; it is impractical. Therefore, around 50-70 nm image forming has been considered as the limits of X-ray lithography. Recently, three types of X-ray mask were proposed which enable 25-35 nm image formation while keeping a practical proximity gap &gt;8 μm. The first is enlarged pattern masks (EPMs), applying a line-narrowing effect by edge diffraction. The second is interference slit masks (ISMs), which form design images by interference effect from the slits of the mask. The third is focusing x-ray masks (FXMs), which form an array of concave lenses using the absorbing materials on the mask membrane. These masks, which reduce mask patterns partially (PRMs: partially reducing masks), relieve the limitation of the proximity gaps. In this article, we discuss the design of the masks, beamlines and procedures of writing for 25 nm image formations.

    DOI

  • Accurate pulse timing control between independent two mode-locked lasers with a novel phase-locked loop

    H Nagaoka, T Miura, K Takasago, F Kannari, K Torizuka, M Washio

    CLEO(R)/PACIFIC RIM 2001, VOL II, TECHNICAL DIGEST   2   190 - 191  2001

     View Summary

    A novel phase-locked loop was developed for synchronization between two mode-locked lasers. The up-converted signal was used to detect phase difference. The relative timing jitter was reduced to less than 500 fs for 30 minutes.

  • Evaluation of in-situ feedback control algorithms for a femtosecond pulse shaping

    A Yada, K Takasago, T Miura, A Endo, K Torizuka, F Kannari, M Washio

    CLEO(R)/PACIFIC RIM 2001, VOL II, TECHNICAL DIGEST   2   192 - 193  2001

     View Summary

    In-situ feedback controlled pulse shaping has demonstrated when a pulse shaping apparatus is placed before the amplifier. For the efficient and rapid control, we evaluated optimization algorithms and parameters.

  • Precise measurement of arbitrary shaped and amplified femtosecond pulses

    K Takasago, A Yada, T Miura, M Washio, F Kannari, K Torizuka, A Endo

    CLEO(R)/PACIFIC RIM 2001, VOL II, TECHNICAL DIGEST   2   732 - 733  2001

     View Summary

    We precisely measured submili-joule and arbitrarily shaped femtosecond pulses with phase-only filters by crosscorrelation and spectral interferogram scheme. The femtosecond pulse shaping apparatus was placed between air oscillator and a regenerative amplifier.

  • Generation of submili-joule picosecond square shaped pulses for low emittance electron generation in photocathode RF-GUN

    K Takasago, A Yada, T Miura, M Washio, F Kannari, K Torizuka, A Endo

    INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS   14 ( 1-4 ) 151 - 156  2001

     View Summary

    Arbitrary shaping of a sub-milli joule femtosecond pulses has been demonstrated by manipulation of optical frequency phase components on the Fourier plane. The shaped pulses were pulse trains and picosecond square pulses for low emittance electron generation in a RF photocathode. Since the pulse shaping apparatus was placed between an oscillator and a pulse stretcher in order to avoid damage to the liquid crystal spatial light modulator, phase-only modulation was used for shaping to avoid damage to optical elements in a regenerative amplifier. The phase modulation was designed by simulated annealing optimization method.

  • High brightness gamma-ray generation via laser-electron collision: Experiment and quantitative considerations

    K Dobashi, M Fukuda, T Hirose, Y Kamiya, Sakai, I, T Aoki, A Higurashi, T Oshima, M Washio, Y Kurihara, T Okugi, T Omori, J Urakawa

    INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS   14 ( 1-4 ) 227 - 231  2001

     View Summary

    We performed an experiment of high brightness gamma(gamma)-rays production through laser-electron(e(-)) collisions using an insertion device with a short focal length of laser optics. Number of generated gamma-rays with the bunch length of 26 psec (r.m.s) was 0.92 x 10(5)/bunch, thus leading to brightness 2.5 x 10(17)/(mm(2) . mrad(2) . 0.1% band-width . sec). Quantitative considerations on the basis of numerical model permitted to elucidate how characteristics of e(-) and laser beam influence collision mechanisms.

  • Demonstration of 8 × 1018 photons/second peaked at 1.8 Å in a relativistic Thomson scattering experiment

    I. V. Pogorelsky, I. Ben-Zvi, T. Hirose, S. Kashiwagi, V. Yakimenko, K. Kusche, P. Siddons, J. Skaritka, T. Kumita, A. Tsunemi, T. Omori, J. Urakawa, M. Washio, K. Yokoya, T. Okugi, Y. Liu, P. He, D. Cline

    Physical Review Special Topics - Accelerators and Beams   3   8 - 15  2000.12

     View Summary

    7.6 × 106 x-ray photons per 3.5 ps pulse are detected within a 1.8-2.3 Å spectral window during a proof-of-principle laser synchrotron source experiment. A 600 MW CO2 laser interacted in a head-on collision with a 60 MeV, 140 A, 3.5 ps electron beam. Both beams were focused to a σ = 32 μm spot. Our next plan is to demonstrate 10 10 x-ray photons per pulse using a CO2 laser of ∼1 TW peak power. © 2000 The American Physical Society.

  • Polarized positron source for the linear collider, JLC

    T Hirose, K Dobashi, Y Kurihara, T Muto, T Omori, T Okugi, Sakai, I, J Urakawa, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   455 ( 1 ) 15 - 24  2000.11

     View Summary

    A comprehensive description of a polarized positron project is presented in terms of physics motivations for utilizing a polarized positron in electron-positron collider experiments, a proof-of-principle experiment and a conceptual design of a polarized positron source for the future linear collider JLC, In order to verify a proposed method of creating highly polarized positron beams via successive two fundamental processes, i.e, Compton scattering and pair creation, we have been performing basic experiments both at KEE; and BNL. First observation of positrons was made at KEK using an electron beam of 1.26 GeV and a laser of 2.33 eV. High-intensity picosecond X-rays were also generated at BNL using a specially designed Compton chamber. In order to realize polarized positron beams of the JLC which have considerably high intensity, i.e, 0.7 x 10(10) e(+)/pulse and a complicated multi-bunch structure, we have achieved a possible scheme for the Compton scattering system and a positron capture section into an L-band linac. (C) 2000 Elsevier Science B.V. All rights reserved.

    DOI

  • Design of polarized-positron generation system

    K Dobashi, M Fukuda, A Higurashi, T Hirose, T Kumita, Y Kurihara, T Muto, T Okugi, T Omori, Sakai, I, J Urakawa, M Washio

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   455 ( 1 ) 32 - 35  2000.11

     View Summary

    We have proposed a new method of generating highly polarized positrons through Compton scattering of polarized laser lights off relativistic electron beams and successive pair creation. To realize high-luminosity laser-electron collisions, we constructed a specially designed chamber which equips off-axis parabolic mirrors with a through hole at the center, This mirror achieves strong focusing of laser lights as well as head-on collisions of laser lights with e(-) beams, so that the luminosity can be significantly increased. A polarimeter is designed for the measurement of positron polarization. (C) 2000 Elsevier Science B.V. All rights reserved.

    DOI

  • Arbitrary shaping of amplified femtosecond pulses with phase-only filters

    Kazuya Takasago, Akira Yada, Taisuke Miura, Masakazu Washio, Fumihiko Kannari, Zhigang Zhang, Kenji Torizuka, Akira Endo

    Conference on Lasers and Electro-Optics Europe - Technical Digest     138  2000.01

     View Summary

    Arbitrarily shaped femtosecond laser pulses can be obtained using amplitude-phase filters or a phase-only filter. The results with a phase-only filter, which does not cause damages in a process of the chirped pulse amplification, were presented. The system consisted of a mode-locked Ti:sapphire laser oscillator, a pulse shaping apparatus, a pulse stretcher, a regenerative amplifier and a pulse compressor. Phase-only filters were designed by simulated annealing optimization method for the targeted profiles.

  • Generation of amplified square shaped picosecond pulses with phase-only filters for an efficient electron generation in an RF-GUN

    K Takasago, A Yada, T Miura, M Washio, F Kannari, ZG Zhang, K Torizuka, A Endo

    LEOS 2000 - IEEE ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS. 1 & 2   1   300 - 301  2000

     View Summary

    Femtosecond pulses were shaped to square shaped picosecond pulses with a phase-only filter. The system used consists of a mode-locked Ti:sapphire laser oscillator, a pulse shaping apparatus, a pulse stretcher, a regenerative amplifier and a pulse compressor. Although the amplifier caused some phase distortion, the experimental results are in good agreement with numerical simulations. © 2000 IEEE.

  • High-duty 1.6 cell s-band RF gun driven by a psec Nd:YAG laser

    Y. Aoki, J. Yang, M. Yorozu, Y. Okada, A. Endo, T. Kozawa, Y. Yoshida, S. Tagawa, M. Washio, X. Wang, I. Ben-Zvi

    Proceedings of the IEEE Particle Accelerator Conference   3   2018 - 2020  1999.12

     View Summary

    The performance tests were done for a 1.6 cell s-band BNL-type photocathode RF electron gun, GUN-IV, under a condition of 1.5 MW RF power input and 266 nm Nd:YAG laser pulse irradiation. As a result, the maximum energy and the maximum charge/bunch were obtained as 1.6 MeV and 120 pC/bunch, respectively. In addition, a sinusoidal behavior of current with the polarization angle of laser light were measured. Furthermore, the change in current as a function of laser injection phase was measured and reasonably reproduced by a numerical calculation.

  • Simulations of racetrack microtron for acceleration of picosecond electron pulse

    M. Washio, R. Kuroda, J. Yang, T. Hori, F. Sakai

    Proceedings of the IEEE Particle Accelerator Conference   4   2298 - 2300  1999.12

     View Summary

    Low emittance sub-picosecond electron pulses are expected to be used in a wide field, such as free electron laser, laser acceleration, femtosecond X-ray generation by inverse Compton scattering, and pulse radiolysis, etc. In order to produce the low emittance sub-picosecond electron pulses, we are developing a compact racetrack microtron (RTM) with a new 5 MeV injection system adopting an laser photo cathode RF gun. The operation of RTM is kept under the steady state of beam loading for long pulse mode so far. We have investigated for the first time by numerical simulation in the case of short- and single-pulse acceleration. As the results, RTM is also useful to accelerate a picosecond electron pulse under a transient state of beam loading. In the simulation, a picosecond electron pulse is accelerated to 139 MeV in RTM for the injection of about 5 MeV pulse with pulse length of 3 picoseconds, charge of 1 nC per pulse, and emittance of 1.8 πmm mrad, which corresponds of output of the RF gun.

  • Ultra-bright X-ray generation using inverse Compton scattering of picosecond CO<inf>2</inf> laser pulses

    A. Tsunemi, A. Endo, I. Pogorelsky, I. Ben-Zvi, K. Kusche, J. Skaritka, V. Yakimenko, T. Hirose, J. Urakawa, T. Omori, M. Washio, Y. Liu, P. He, D. Cline

    Proceedings of the IEEE Particle Accelerator Conference   4   2552 - 2554  1999.12

     View Summary

    Laser-Compton scattering with picosecond CO2 laser pulses is proposed for generation of high-brightness x-rays. The interaction chamber has been developed and the experiment is scheduled for the generation of the x-rays of 4.7 keV, 107 photons in 10-ps pulse width using 50-MeV, 0.5-nC relativistic electron bunches and 6 GW CO2 laser.

  • Compton scattering of laser off electron beams to generate polarized positron beams for future linear colliders

    T Hirose, K Dobashi, T Kumita, Y Kurihara, T Omori, T Okugi, K Sugiyama, A Tsunemi, J Urakawa, M Washio

    INTERNATIONAL WORKSHOP ON NONDESTRUCTIVE TESTING AND COMPUTER SIMULATIONS IN SCIENCE AND ENGINEERING   3687   9 - 22  1999

     View Summary

    We observed positron (e(+)) production for the first time on the basis of the new idea that gamma-rays produded via Compton scattering of laser lights off electron (e(-)) beams of 1.26 GeV/c provided by the ATF damping ring can create pairs of e(+) and e(-). It is verified that the production rates of e(+/-) and gamma-rays are consistent with each other as well as in good agreement with theoretical predictions. We also attain a conceptual design of a polarized e(+) source for the future linear collide JLC which requires high intesity e(+) beams with a complicated time structure of multi-bunching.

  • Backward Compton scattering of picosecond CO2 laser pulses using relativistic electron beam for the bright X-ray generation

    Akira Tsunemi, Akira Endo, Igor Pogorelsky, Ilan Ben-Zvi, Tachishige Hirose, Tsunehiko Omori, Junji Urakawa, Masakazu Washio

    CLEO/Pacific Rim 1999 - Pacific Rim Conference on Lasers and Electro-Optics   3   926 - 927  1999

     View Summary

    Laser-Compton scattering can generate X-rays or y-rays with high brightness by applying highpeak- power laser pulses to relativistic electron bunches. We have proposed laser-Compton scattering to generate polarized y -rays which can induce pair-creation to produce polarized positrons for JLC (Japan Linear Collider) project[ 11. As a photon source of the Compton scattering, a picosecond CO2 laser system is going to be applied for our experiment because of the higher scattering cross section than near-infiared solid-state lasers, laser power scalability, the laser efficiency and the possibility of high-repetition rated operation. Not only for the JLC positrons source, Compton scattering with Ca-laser has a possibility to be a compact high intensity X-ray source as an alternative of synchrotron radiation source[2]. We have been developing a laser-Compton scattering chamber for a preliminary experiment, in which COz laser pulses and electron bunches propagate along the same axis in opposite direction and collide at the focal point. Fig. 1 is the sketch of the Compton chamber to be applied in the beamline of the Accelerator-Test-Facility in Brookhaven National Laboratory. Picosecond CO2 laser beams are introduced &amp
    om the side window and focused by an off-axis parabolic Cu mirror of 50 mm diameter with the focal length of 15 cm. Cu mirror has 5 mm diameter hole along the electron beam axis to have electrons pass through. An axicon telescope system made of ZnSe is placed on the CO2 beam axis just before the Compton chamber in order to modify spatial profiles as shown in Fig. 2-(a) to accommodate to the mirror with holes. Fig. 2-(b) represents a numerically calculated CO2 beam profile at the focal point. The estimated beam waist size is about 100 pm, which is almost same as the electron beam size at the colliding point. After the focal point, the diverging laser beams are paralleled by another Cu mirror and extracted fiom the chamber.

    DOI

  • Construction of high-quality polarized-positrons beam-line VII : Overview and pulsing system

    IIJIMA Hokuto, IGURA Yoshiyuki, IRAKO Mitsuhiro, OMORI Tsunehiko, KANEKO Junichi, KUMITA Tetsuro, KURIHARA Yoshimasa, CHIBA Masami, NAKAJYO Akinobu, HAMATSU Ryosuke, HIROSE Tachisige, HIROSE Masafumi, FUKUSHIMA Manabu, WASHIO Masakazu, MONDAL N.N.

    Meeting abstracts of the Physical Society of Japan   53 ( 1 ) 339 - 339  1998.03

    CiNii

  • Output beam characteristics of 150 MeV microtron

    T Hori, H Tsutsui, D Amano, M Washio, J Yang, K Tani

    PROCEEDINGS OF THE 1997 PARTICLE ACCELERATOR CONFERENCE, VOLS 1-3   1   1266 - 1268  1998

     View Summary

    Sub-picosecond electron pulses are desirable for generating femtosecond X-ray pulses. By numerical simulation, it has become clear that racetrack microtron (RTM) has unique features to produce very short electron bunches by itself. In addition, it has proved experimentally that RTM has beneficial characteristics to accelerate only an excellent quality beam in both emittance and energy spread. The measured and calculated results of such distinctives are shown in this paper.

  • 20p-G-4 LASER COOLING OF POSITRONIUM IV : Measurement of thermally desorbed positronium

    Mondal N.N., Iijima Hokuto, Igura Yoshiyuki, Irako Mituhiro, Kaneko Junichi, Kumita Tetsuro, Chiba Masami, Hamatsu Ryosuke, Hirose Tachishige, Endo Akira, Yorozu Masashi, Washio Masakazu, Oomori Tunehiko, Kurihara Yoshimasa, Kobayashi Katsuyuki

    Meeting abstracts of the Physical Society of Japan   52 ( 2 ) 18 - 18  1997.09

    CiNii

  • 20p-G-7 高品質偏極低速陽電子ビームラインの構築VI : ビームラインの性能評価

    福島 学, 飯島 北斗, 五十子 満大, 汲田 哲郎, 千葉 雅美, 中條 晃伸, 浜津 良輔, 広瀬 立成, 広瀬 雅文, 鷲尾 方一, Mazumdar N.C.

    日本物理学会講演概要集   52 ( 2 ) 18 - 18  1997.09

    CiNii

  • 20p-G-1 Laser cooling of positronium I : High-density positronum and short-time laser cooling

    Iijima Hokuto, Igura Yoshiyuki, Irako Mitsuhiro, Endo Akira, Omori Tsunehiko, Kaneko Junichi, Kumita Tetsuro, Kurihara Yoshimasa, Kobayashi Katsuyuki, Chiba Masami, Hamatsu Ryosuke, Hirose Tachisige, Hirose Masafumi, Yorozu Masashi, Washio Masakazu, Mondal N.N.

    Meeting abstracts of the Physical Society of Japan   52 ( 2 ) 17 - 17  1997.09

    CiNii

  • 20p-G-2 LASER COOLING OF POSITRONIUM II : 1s→2s Excitation of H atom and 1s→2p Excitation of positronium

    Igura Yoshiyuki, Iijima Hokuto, Irako Mituhiro, Kaneko Junichi, Kumita Tetsuro, Chiba Masami, Hamatsu Ryosuke, Hirose Tachishige, Mondal N.N., Endo Akira, Yorozu Masashi, Washio Masakazu, Omori Tunehiko, Kurihara Yoshimasa, Kobayashi katsuyuki

    Meeting abstracts of the Physical Society of Japan   52 ( 2 ) 17 - 17  1997.09

    CiNii

  • 20p-G-3 Laser cooling of positronium III : Development of Positron traping system

    Kaneko Jun'ichi, Iijima Hokuto, Igura Yoshiyuki, Irako Mitsuhiro, Endo Akira, Omori Tsunehiko, Kumita Tetsuro, Kurihara Yoshimasa, Kobayashi Katsuyuki, Chiba Masami, Hamatsu Ryosuke, Hirose Tachishige, Hirose Masafumi, Yorozu Masashi, Washio Masakazu, Mondal N.N.

    Meeting abstracts of the Physical Society of Japan   52 ( 2 ) 17 - 17  1997.09

    CiNii

  • Report on Symposium on Applied Radiation Chemistry

    WASHIO Masakazu

      63   42 - 44  1997.03

    CiNii

  • 29p-YS-2 Development of Polarized Positron Source(XI):-Measurement of Beam Polarization using Magnetic Quench of Positronium II-

    YANG Jinfeng, ISIYAMA Hitoshi, IRAKO Mitsuhiro, OMORI Tsunehiko, OKUGI Toshiyuki, KAWASAKI Noboru, KUMITA Tethuro, KURIHARA Yoshimasa, TAKEUCHI Yasunori, CHIBA Masami, NAKABUSHI Hiromitsu, HAMATSU Ryosuke, HIROSE Tachishige, HIROSE Masafumi, MAZUMDAR NiranjanChandra, MATSUMOTO Toshihiro, YOSHIOKA Masakazu, WASHIO Masakazu

    Meeting abstracts of the Physical Society of Japan   52 ( 1 ) 24 - 24  1997.03

    CiNii

  • 29p-YS-4 Construction of the high-quality polarized-Positron beam-line(III) : Design and prodction of Wienfilter

    Fukushima Manabu, Iijima Hokuto, Irako Mitsuhiro, Kumita Tetsurou, Chiba Masami, Hamatsu Ryousuke, Hirose Tachisige, Hirose Masafumi, Yang Jnfeng, Washio Masakazu, N.C Mazumdar

    Meeting abstracts of the Physical Society of Japan   52 ( 1 ) 25 - 25  1997.03

    CiNii

  • 29p-YS-5 Construction of high-quality polarized-positrons beam-line IV : Production of chopper and buncher

    Iijima Hokuto, Irako Mitsuhiro, Kumita Tetsuro, Chiba Masami, Hamatsu Ryosuke, Hirose Tachisige, Hirose Masafumi, Fukushima Manabu, Yang Jinfeng, Washio Masakazu, N.C. Mazumdar

    Meeting abstracts of the Physical Society of Japan   52 ( 1 ) 25 - 25  1997.03

    CiNii

  • 29p-YS-6 Construction of high-quality polarized positron beam line : Behaviour of polarized slow positrons in materials

    N.C. Mazumdar, Iijima Hokuto, Irako Mitsuhiro, Kumita Tetsuro, Chiba Masami, Hamatsu Ryosuke, Hirose Tachisige, Hirose Masafumi, Fukushima Manabu, Yang Jinfeng, Washio Masakazu

    Meeting abstracts of the Physical Society of Japan   52 ( 1 ) 25 - 25  1997.03

    CiNii

  • Pico second CO<inf>2</inf>laser system as a laser-Compton scattering source for high power and high repetition-rated γ-ray generation

    Akira Tsunemi, Akira Endo, Masakazu Washio, Tachishige Hirose, Yoshimasa Kurihara, Tsunehiko Oomori, Junji Urakawa

    Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest     14 - 15  1997.01

     View Summary

    A high power pico second CO2laser system is proposed for the generation of high power and high repetition-rated γ-ray beams by Compton scattering. The γ-ray is adopted for the production of positron beams in the Japan Linear Collider (JLC). One hundred independently operated p-sec CO2laser systems are placed around the Compton interaction point and triggered with the repetition rate of 150 Hz. A reflection mirror system composed of 100 flat mirrors corresponding to each laser unit is placed around the axis of the electron beams. Each p-sec CO2laser system is composed of a cw-CO2oscillator, an optical switching section, a pre-amplifier with a regenerative amplifier system and a multiple pass main amplifier.

  • A compact cyclotron based slow positron beam and a new positron pulsing system

    Masafumi Hirose, Terunobu Nakajyo, Masakazu Washio

    Applied Surface Science   116   63 - 67  1997

     View Summary

    A new positron pulsing system has been developed for the first time using an induction cavity. The slow positron beam is provided by using a compact cyclotron. In order to use the slow positron beam from the compact cyclotron for the analyses of material surfaces such as variable-energy positron lifetime spectroscopy, we have developed a new positron pulsing system. In the new system, slow positron beam bunching is performed by applying an induction cavity instead of a usual rf cavity. The induction cavity makes it possible to produce any kind of electric field change according to time. Hence the bunching efficiency of the induction cavity should be higher than that of rf cavity which can produce only sine curves electric field change according to time. In a preliminary slow positron beam bunching test using the induction cavity, a pulse width (FWHM) of about 1 ns has been achieved. A fine tuning for achieving a pulse width of 150 ps is in progress. Another new compact cyclotron and a new slow positron beam facility are also under construction next to the present ones. The design of the new facility will be also reported.

    DOI

  • Construction of polarized slow-positron beams using a compact cyclotron

    T. Kumita, M. Chiba, R. Hamatsu, M. Hirose, T. Hirose, H. Iijima, M. Irako, N. Kawasaki, Y. Kurihara, T. Matsumoto, H. Nakabushi, T. Omori, Y. Takeuchi, M. Washio, J. Yang

    Applied Surface Science   116   1 - 6  1997

     View Summary

    We have constructed a polarized positron beam using positrons provided from the β+ decay of 27Si with the half-life of 4.1 s and the maximum β+ energy of 3.85 MeV. This isotope is produced via the 27Al(p, n)27Si reaction caused by proton irradiation using a compact proton cyclotron. The intensity of this beam is measured to be 5 × 105 e+/s for protons with the energy of 18 MeV and the current of 30 μA. A pair of Monte Carlo simulation programs has been developed to calculate depolarization of positrons in our beam channel. One program simulates spin motion of the positron under electric and magnetic fields, while the other simulates depolarization due to multiple Coulomb scattering in matter. Using these simulators, we designed a special polarimeter by means of magnetic quenching of ortho-positronium and measured a quenched lifetime of ortho-positronium under the magnetic field of 0.4, 2.5 and 4.0 kG leading to the average polarization of 33.4 ± 5.3%, which is consistent with the estimation based on the Monte Carlo simulations.

    DOI

  • Depolarization of polarized slow positrons in solids

    J Yang, M Chiba, R Hamatsu, M Hirose, T Hirose, H Iijima, M Irako, T Kumita, N Mazumdar, H Nakabushi, M Washio

    POSITRON ANNIHILATION   255-2   632 - 634  1997

     View Summary

    We have investigated spin-precession mechanisms of polarized stow positrons in materials caused by multiple Coulomb scatterings, Bhabha scatterings and bremsstrahlungs. The depolarizations of polarized slow positrons in various materials have been estimated and found that the degree of depolarization is strongly dependent on the atomic number of materials. A Monte-Carlo simulation program, in which the theoretical formulations of spin precession due to the three processes mentioned above are incorporated, have been developed and applied successfully for designing the production system of polarized slow positrons.

  • Polarization measurement of a slow positron beam generated with a compact cyclotron

    T Kumita, M Chiba, R Hamatsu, M Hirose, T Hirose, H Iijima, M Irako, M Washio, J Yang

    POSITRON ANNIHILATION   255-2   656 - 658  1997

     View Summary

    We measured polarization of a slow positron beam produced in online-manner via the 27 Al(p,n) 27Si reaction caused by proton irradiation The intensity of this beam is measured to be 5105 e(+)/sec for protons with the energy of 18MeV and the current of 30mA. The polarization measurement makes use of the magnetic quenching of positronium due to Zeeman effect in a magnetic field of a several kG. The polarization of the beam is evaluated to be 38.44.0(statistical)5.8(systematic)%, which is consistent with the estimation based on our Monte Carlo simulations including depolarization processes in matter.

  • Construction of a bunched beam of polarized slow-positron

    M Irako, M Chiba, M Fukusima, R Hamatsu, M Hirose, T Hirose, H Iijima, T Kumita, NC Mazumdar, M Washio

    POSITRON ANNIHILATION   255-2   750 - 753  1997

     View Summary

    We have constructed a polarized slow-positron beam generator TOPPS based on the design principle that the beam is bunched and the spin direction is controllable. The positrons from the 150 mCi Na-22 are implanted on the tungsten moderator of 10 mu m. The TOPPS is optimized to suppress the depolarization of the positron beams by utilizing the programs which we developed to calculate the spin motion of charged particles in electric and magnetic fields as well as in materials.

  • A new positron pulsing system with a compact cyclotron based slow positron beam

    M Hirose, T Nakajyo, M Washio

    POSITRON ANNIHILATION   255-2   674 - 676  1997

     View Summary

    A new positron pulsing system has been developed for the first time using an induction cavity. The slow positron beam is provided by using a compact cyclotron. In order to use the slow positron beam from the compact cyclotron for the analyses of material surfaces such as variable-energy positron lifetime spectroscopy, we have developed a new position pulsing system, In the new system, slow positron beam bunching is performed by applying an induction cavity instead of a usual rf cavity. The induction cavity makes it possible to produce any kind of electric field change according to time. Hence the bunching efficiency of the induction cavity should be higher than that of rf cavity which can produce only sine curves electric field change according to time. In a preliminary slow positron beam bunching test using the induction cavity, a pulse width of about 300 ps has been achieved. A fine tuning for achieving a pulse width of 150 ps is in progress, Another new compact cyclotron and a new slow position beam facility have also been constructed next to the present ones. The design of the new facility will be also reported.

  • 6p-B-2 Constraction of a beam line for high quality polarized postrons II

    Fukusima Manabu, Iijima Hokuto, Irako Mitsuhiro, Kumita Tetsuro, Chiba Masami, Hamatsu Ryousuke, Hirose Tachisige, Hirose Masafumi, Yang Jinfeng, Washio Masakazu, Mazumdar N.C., Mondal N.N.

    Abstracts of the meeting of the Physical Society of Japan. Sectional meeting   1996 ( 1 ) 35 - 35  1996.09

    CiNii

  • 6p-B-1 Constraction of a beam line for high quality polarized postrons I

    Iijima Hokuto, Irako Mitsuhiro, Kumita Tetsuro, Chiba Masami, Hamatsu Ryousuke, Hirose Tachisige, Hirose Masafumi, Fukusima Manabu, Yang Jinfeng, Washio Masakazu, Mazumdar N.C., Mondal N.N.

    Abstracts of the meeting of the Physical Society of Japan. Sectional meeting   1996 ( 1 ) 34 - 34  1996.09

    CiNii

  • 大型陽電子源用炭酸ガスレ-ザシステムの概念設計

    遠藤 彰, 広瀬 雅文, 鷲尾 方一

    住友重機械技報   43 ( 129 ) 1 - 4  1995.12

    CiNii

  • 30a-SK-6 偏極陽電子源の開発VIII : Compton散乱を用いた偏極陽電子源の開発

    奥本 敏行, 石山 仁, 遠藤 彰, 大森 恒彦, 河崎 昇, 汲田 哲郎, 栗原 良将, 小林 克行, 竹内 康紀, 千葉 雅美, 伸伏 広光, 広瀬 立成, 広瀬 雅文, 浜津 良輔, 松本 利広, 楊 金峰, 吉岡 正和, 鷲尾 方一

    日本物理学会講演概要集. 秋の分科会   1995 ( 1 ) 48 - 48  1995.09

    CiNii

  • PRODUCTION OF AN INTENSE SLOW POSITRON BEAM USING A COMPACT CYCLOTRON

    M HIROSE, M WASHIO, K TAKAHASHI

    APPLIED SURFACE SCIENCE   85 ( 1-4 ) 111 - 117  1995.01

     View Summary

    An intense slow positron beam has been produced for the first time using a compact cyclotron. Used in an on-line mode, an intense positron source has been produced by making use of the Al-27(p,n)Si-27 reaction. A transmission type target system has been developed in order to avoid decreases in the slow positron beam intensity due to the damage induced in the moderator by proton irradiation. In the near future beam intensities of the order of 10(7)-10(9) slow e(+)/s are expected from this system.

    DOI

  • High aspect ratio micromachining Teflon by direct exposure to synchrotron radiation

    Y. Zhang, T. Katoh, M. Washio, H. Yamada, S. Hamada

    Applied Physics Letters   67   872  1995

     View Summary

    Micromachining Teflon was achieved by direct exposure to synchrotron radiation and the microstructures made had the smallest surface detail down to 20 μm with structural height of more than 200 μm, that is, aspect ratio on the order of 10. The quality of micromachining Teflon by this process was found to be critically dependent on photon flux of the synchrotron radiation. Analysis of the mass distribution of gaseous species formed upon this process suggested that photochemical processes rather than pyrolytic processes may still dominate.© 1995 American Institute of Physics.

    DOI

  • RATES FOR INTRAMOLECULAR EXCIMER FORMATION OF POLY(ALPHA-METHYLSTYRENE) MEASURED BY USING PICOSECOND PULSE-RADIOLYSIS

    H ITAGAKI, M WASHIO, S TAGAWA

    POLYMER BULLETIN   28 ( 2 ) 197 - 202  1992.04

     View Summary

    The rate constants for intramolecular excimer formation, k(DM), of poly(alpha-methylstyrene) with different molecular weight were determined by using picosecond pulse radiolysis. Values of k(DM) for poly(alpha-methylstyrene) are a little smaller than those for polystyrene with nearly same molecular weight. It appears to be mainly due to steric hindrance by methyl substituent of main chain.

    DOI

  • LOCAL MOLECULAR-MOTION OF POLYSTYRENE MODEL COMPOUNDS MEASURED BY PICOSECOND PULSE-RADIOLYSIS .3. DIASTEREOMERIC STYRENE DIMER, TRIMER, AND TETRAMER IN POLY(METHYL METHACRYLATE) SOLID-SOLUTION

    H ITAGAKI, K HORIE, MITA, I, M WASHIO, S TAGAWA, Y TABATA, H SATO, Y TANAKA

    MACROMOLECULES   23 ( 6 ) 1686 - 1690  1990.03

     View Summary

    The photophysical properties of diastereomeric oligostyrenes, meso (m) and racemic (r) 4,6- diphenylnonanes (PS2); mm-, mr-, and rr-4,6,8-triphenylundecanes (PS3); and mmm-, mmr-, mrm-, rrm-, and rrr-4,6,8,10-tetraphenyltridecanes (PS4), in poly(methyl methacrylate) (PMMA) were studied by photostationary and transient measurements. The fluorescence spectra of PS2, PS3, and PS4 with meso diads exhibited excimer fluorescence even in PMMA solid solution where conformational changes are restricted, suggesting that the population of tt, an excimer conformer, in the meso diad is noticeable even in low molecular weight compounds such as PS2, PS3, or PS4. Monomer fluorescence of oligostyrenes in PMMA decayed single exponentially with the same time constant as that of cumene. The observed monomer fluorescence is assumed to come from a molecule that has no excimer conformer while a molecule having excimer conformers does not exhibit monomer fluorescence. Fluorescence polarization measurements at 77 K and at room temperature demonstrated that the reorientational motion of phenyl groups was not perfectly restricted in PMMA solid solution. The efficiency of the energy migration among the phenyl rings in PS2, PS3, and PS4 was not so outstanding that it could induce the fluorescence depolarization. © 1990, American Chemical Society. All rights reserved.

    DOI

  • Pulse radiolyses of anthraquinone and anthraquinone-triethylamine in acetonitrile and toluene at room temperature

    Toshihiro Nakayama, Kiminori Ushida, Kumao Hamanoue, Masakazu Washio, Seiichi Tagawa, Yoneho Tabata

    Journal of the Chemical Society, Faraday Transactions   86 ( 1 ) 95 - 103  1990

     View Summary

    Nanosecond pulse radiolysis of anthraquinone (AQ) in several solvents has been performed at room temperature, and the following results are obtained: (1) In acetonitrile (CH3CN), the formation of triplet AQ and a free-radical anion (AQ.-) of AQ is observed. The former is produced by energy transfer from an excited neutral of CH3CN which may be produced via the geminate recombination of a radical cation and a radical anion of CH3CN in a spur, while the latter is produced by electron transfer from anionic species such as a solvated electron, a monomeric and/or a dimeric radical anion of CH3CN. In CH3CN-triethylamine (TEA), both free AQ.- and triplet AQ mentioned above are also produced
    however, the latter reacts with TEA, giving rise to the formation of free AQ.- (from the second triplet state of AQ) and an exciplex of the lowest triplet state of AQ with ground-state TEA. This exciplex decomposes to free AQ.- and the radical cation of TEA. (2) In toluene, only triplet AQ is produced by energy transfer from triplet toluene to AQ, and, in the presence of TEA, the formation of the triplet exciplex of AQ-TEA is observed. On a microsecond timescale, however, this exciplex changes to a contact ion pair followed by proton transfer, generating anthrasemiquinone radical and triethylamine radical in accordance with the result of photolysis.

    DOI

  • LOCAL MOLECULAR-MOTION OF POLYSTYRENE MODEL COMPOUNDS MEASURED BY PICOSECOND PULSE-RADIOLYSIS .2. MULTICOMPONENT FLUORESCENCE DECAY CURVES OF DIASTEREOMERIC STYRENE TRIMERS

    H ITAGAKI, K HORIE, MITA, I, M WASHIO, S TAGAWA, Y TABATA, H SATO, Y TANAKA

    MACROMOLECULES   22 ( 5 ) 2520 - 2525  1989.05

     View Summary

    The dynamics of intramolecular excimer formation in isotactic (mm), syndiotactic (rr), and heterotactic (mr) 4,6,8-triphenylundecanes (PS3), which are diastereomeric trimer model compounds of polystyrene, were investigated by picosecond pulse radiolysis. The monomeric fluorescence of rr PS3 decays single exponentially with a time constant of 7.4 ns, while those of mm PS3 and mr PS3 decay dual exponentially with time constants of ~0.5 and 4 ns. The multicomponent fluorescence decays are influenced by local molecular motion (conformational change). The results suggest that the phenyl groups do not rotate independently around the carbon-carbon bonds of the backbone but that their rotation involves a cooperative motion of backbone chain bonds. The existence of singlet energy migration is established by the fact that the monomeric fluorescence decay curve of mr PS3 does not have as long a decay constant as the curves of the racemic isomers r PS2 and rr PS3 have. © 1989, American Chemical Society. All rights reserved.

    DOI

  • STUDY OF RADIATION-INDUCED REACTION IN LIQUID CARBON-TETRACHLORIDE BY MEANS OF PICOSECOND PULSE-RADIOLYSIS

    M WASHIO, Y YOSHIDA, N HAYASHI, H KOBAYASHI, S TAGAWA, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   34 ( 1 ) 115 - 120  1989

     View Summary

    Pico- and nano-second pulse radiolysis was applied to the study of the radiolysis of carbon tetrachloride (CCl 4 ). In the u.v.-region, two different absorbing species were observed by using the twin linac pulse radiolysis technique. The component decays within 100 ps and the other component has a very long lifetime (about 100 ns). This long lifetime component has been reported in previous work. The absorption band of the very short lifetime component is broader than that of the long lifetime component in the u.v.-region. This very short lifetime component is considered to be CCl {plus sign, dot below}4 . In the visible region, growth of absorption and following first order decay were observed. The growth of the absorption was measured very precisely using the twin linac pluse radiolysis and the analysis was carried out using the analytical solution of the Smoluchowski equation. Exponential function (R(r, r 0 ) = (1/r 0 ) exp(-r/r 0 )) as the initial distribution function of the geminate ion pair gives a better fit than the gaussian. However using the reported G fi /G tot (0.02), even the exponential is still not fitted completely for the experimental results. A more complex initial distribution must be introduced. © 1989.

    DOI

  • INTRAMOLECULAR EXCIMER FORMATION OF DIASTEREOISOMERIC MODEL COMPOUNDS OF POLYSTYRENE IN FLUID SOLUTION - THEIR LOCAL MOLECULAR-MOTION AND PHOTOPHYSICAL PROPERTIES

    H ITAGAKI, K HORIE, MITA, I, M WASHIO, S TAGAWA, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   34 ( 4 ) 597 - 603  1989

     View Summary

    The dynamic process of intramolecular eximer formation in diastereoisomeric oligamers [dimers: meso (m)- and racemic (r)-4,6-diphenylnonane (PS2), trimers: mm-, mr- and rr-4, 6, 8-triphenylundecane (PS3), and tetramers: mmm-, mmr-, mrm-, rrm-, and rrr-4, 6, 8, 10-tetraphenyltridecane (PS4)], model compounds of polystyrene, was investigated by using a picosecond pulse radiolysis technique. Monomer fluorescence of all-racemic isomers (r PS2, rr PS3, rrr PS4) and rrm PS4 decays single-exponentially, while that of other isomers decays dual-exponentially. Multicomponent fluorescence decay curves are supposed to be mainly induced by conformational changes. The results suggest that the excimer in oligostyrenes (or polystyrene) is formed mainly in meso diad. It is definitely proved that there exists singlet energy migration in styrene trimer and tetramer systems. The conformational change in PS3 and PS4 is concluded to occur by way of cooperative motions in backbone chains bond such as a crankshaft transition, not by way of independent rotation around each carbon-carbon bond of the backbone chain. © 1989.

    DOI

  • Pulse radiolysis studies on the transient species of aromatic molecules in chlorinated hydrocarbon solutions

    Masakazu Washio, Seiichi Tagawa, Kazuo Furuya, Nariyuki Hayashi, Yoneho Tabata

    International Journal of Radiation Applications and Instrumentation. Part   34 ( 4 ) 533 - 537  1989

     View Summary

    Pulse radiolysis has been carried out to identify the transient species produced by the pulsed electron irradiation for the several kinds of combination of the solutions of aromatic hydrocarbons (benzene, naphthalene and pyrene) in chlorinated hydrocarbons (CCl4, CHCl3, and CH2Cl2). Charge-transfer complex between aromatic ring and Cl atom has been observed for benzene solutions in above three solvents. Naphthalene monomer and dimer cation radicals have been observed for the solutions in CHCl3 and CH2Cl2. Monomer cation radicals of pyrene has been observed for the solution of pyrene in CCl4, and monomer and dimer cation radicals of pyrene have been observed for the solutions in CHCl3 and CH2Cl2. © 1989.

    DOI

  • MUON SPIN-RESONANCE AND PULSE-RADIOLYSIS STUDIES OF LIQUID CS2

    T AZUMA, M WASHIO, Y TABATA, Y ITO, K NISHIYAMA, Y MIYAKE, K NAGAMINE

    RADIATION PHYSICS AND CHEMISTRY   34 ( 4 ) 659 - 667  1989

     View Summary

    An extensive study of positive muon chemistry has been performed in order to clarify the mechanism of the large loss of the muon spin polarization in CS2. The main technique used in the experiments was &quot;muon spin resonance&quot;. After a brief demonstration of the usefulness of the resonance method, its application to the study of both the diamagnetic muon and the muonium-substituted free radicals in CS2 are described. The results show an existence of muonium-substituted free radicals in CS2, but they were stable only in limited conditions. The diamagnetic muon fraction, which is only about 0.2 at first, was found to increase slowly with time. This kind of slow formation of the muon state has been found for the first time by the resonance method in CS2. From the combination of the obtained results, we infer that the loss of the muon spin polarization is due to reactions of the muonium-substituted free radicals, for which aggregation effect of the substance plays an important role. Results of nanosecond pulse radiolysis of CS2 are also presented compared with the results of the muon chemistry. © 1989.

    DOI

  • Pulse radiolysis studies on liquid alkanes and related polymers

    S. Tagawa, N. Hayashi, Y. Yoshida, M. Washio, Y. Tabata

    International Journal of Radiation Applications and Instrumentation. Part   34 ( 4 ) 503 - 511  1989

     View Summary

    Absorption spectra of alkane radical cations, alkane excited states, and alkyl radicals and electrons in irradiated neat liquid alkanes at room temperature were assigned on subnanosecond and nanosecond time scale after an electron pulse. Two broad visible and near-infrared absorption bands of alkane excited states and radical cations, and UV absorption band of alkyl radicals were observed in neat n-alkanes. In neat cyclohexane and trans-decalin, very broad visible absorption band mainly due to alkane excited states and UV absorption band of alkyl radicals were observed. In neat neopentane and isooctane, visible absorption bands were not observed, although UV absorption bands of alkyl radicals were observed. The wavelengths of absorptive peaks of alkane radical cations and excited states become longer with increasing the number of carbon atoms of n-alkanes. The lifetimes of alkane radical cations become shorter with decreasing the number of carbon atoms of n-alkanes and are shorter than those of electrons in neat alkanes. The main processes of the alkyl radical formation finish within the time resolution of our system (about 20 ps). The alkyl radicals are produced mainly from excited radicals cations and partly from higher excited states, the lowest excited states, radical cations, and thermal hydrogen atoms. In irradiated ethylene-propylene copolymers, broad absorption bands of excited states and tail parts of absorption bands of radical cations and electrons were observed in visible and near-infrared region, although UV absorption of alkyl radicals was not confirmed lack of transparency of polymer films. © 1989.

    DOI

  • PICOSECOND PULSE-RADIOLYSIS ON GEMINATE ION RECOMBINATION AND FORMATION OF SOLUTE EXCITED-STATE IN LIQUID CYCLOHEXANE

    Y YOSHIDA, S TAGAWA, M WASHIO, H KOBAYASHI, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   34 ( 4 ) 493 - 496  1989

     View Summary

    The geminate ion recombination and the formation process of solute excited states in solutions of biphenyl were studied in cyclohexane by means of picosecond pulse radiolysis with absorption and emission spectroscopies. The time-dependent behavior of the biphenyl anion was analyzed with the diffusion theory in the solute-solvent system. By applying this analysis to the time-dependent fluorescence from excited states of biphenyl, yields of the excited states through various formation processes were deduced. Also, yield of excited states of cyclohexane in the absence of solutes was estimated. © 1989.

    DOI

  • Intramolecular Excimer Formation of Diastereomeric Styrene Trimers Measued by Picosecond Pulse Radiolysis

    Hideyuki Itagaki, Kazuyuki Horie, Itaru Mita, Masakazu Washio, Seiichi Tagawa, Yoneho Tabata, Hisaya Sato, Yasuyuki Tanaka

    NIPPON KAGAKU KAISHI   1989 ( 8 ) 1299 - 1303  1989

    DOI

  • PICOSECOND ELECTRON-BEAM AND SYNCHROTRON RADIATION PULSE-RADIOLYSIS FOR STUDIES ON ELECTRON-BEAM AND X-RAY RESISTS

    Y YOSHIDA, H SHIBATA, S TAGAWA, M WASHIO, Y TABATA, N KOUCHI, A OGATA

    ADVANCES IN RESIST TECHNOLOGY AND PROCESSING VI   1086   274 - 281  1989

     View Summary

    Picosecond electron-beam and synchrotron radiation pulse radiolysis are powerful method to study the reaction mechanism in irradiated electron beam and X-ray resists. The primary processes can be detected spectroscopically by using both pulse radiolysis systems. The details of the pulse radiolysis systems and a typical exsample of pulse radiolysis studies on the resists are introduced. © 1989 SPIE.

    DOI

  • PICOSECOND PULSE-RADIOLYSIS ON GEMINATE ION RECOMBINATION AND FORMATION OF SOLUTE EXCITED-STATE IN LIQUID CYCLOHEXANE

    Y YOSHIDA, S TAGAWA, M WASHIO, H KOBAYASHI, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   34 ( 4 ) 493 - 496  1989

     View Summary

    The geminate ion recombination and the formation process of solute excited states in solutions of biphenyl were studied in cyclohexane by means of picosecond pulse radiolysis with absorption and emission spectroscopies. The time-dependent behavior of the biphenyl anion was analyzed using diffusion theory in the solute-solvent system. By applying this analysis to the time-dependent fluorescence from excited states of biphenyl, yields of the excited states through various formation processes were deduced. Also, yield of excited states of cyclohexane in the absence of solutes was estimated.

  • INTRAMOLECULAR EXCIMER FORMATION OF DIASTEREOISOMERIC MODEL COMPOUNDS OF POLYSTYRENE IN FLUID SOLUTION - THEIR LOCAL MOLECULAR-MOTION AND PHOTOPHYSICAL PROPERTIES

    H ITAGAKI, K HORIE, MITA, I, M WASHIO, S TAGAWA, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   34 ( 4 ) 597 - 603  1989

     View Summary

    The dynamic process of intramolecular excimer formation in diastereoisomeric oligomers [dimers: meso (m)- and racemic (r)-4,6-diphenylnonane (PS2), trimers: mm-, mr- and rr-4, 6,8-triphenylundecane (PS3), and tetramers: mmm-, mmr-, mrm-, rrm-, and rrr-4, 6,8, 10-tetraphenyltridecane (PS4)], model compounds of polystyrene, was investigated by using a picosecond pulse radiolysis technique. Monomer fluorescence of all-racemic isomers (r PS2, rr PS3, rrr PS4) and rrm PS4 decays single-exponentially, while that of other isomers decays dual-exponentially. Multicomponent fluorescence decay curves are supposed to be mainly induced by conformational changes. The results suggest that the excimer in oligostyrenes (or polystyrene) is formed mainly in meso diad. It is proved that there exists singlet energy migration in styrene trimer and tetramer systems. The conformational change in PS3 and PS4 is concluded to occur by cooperative motions in backbone chains bond such as a crankshaft transition, but not by way of independent rotation around each carbon-carbon bond of the backbone chain.

  • MUON SPIN-RESONANCE AND PULSE-RADIOLYSIS STUDIES OF LIQUID CS2

    T AZUMA, M WASHIO, Y TABATA, Y ITO, K NISHIYAMA, Y MIYAKE, K NAGAMINE

    RADIATION PHYSICS AND CHEMISTRY   34 ( 4 ) 659 - 667  1989

     View Summary

    An extensive study of positive muon chemistry has been performed in order to clarify the mechanism of the large loss of the muon spin polarization in CS2. The main technique used in the experiments was &#039;muon spin resonance&#039;. After a brief demonstration of the usefulness of the resonance method, its application to the study of both the diamagnetic muon and the muonium-substituted free radicals in CS2 are described. The results show an existence of muonium-substituted free radicals in CS2, but they were stable only in limited conditions. The diamagnetic muon fraction, which is only about 0.2 at first, was found to increase slowly with time. This kind of slow formation of muon state has been found for the first time by the resonance method in CS2. From the combination of the obtained results, we infer that the loss of the muon spin polarization is due to reactions of the muonium-substituted free radicals, for which aggregation effect of the substance plays an important role. Results of nanosecond pulse radiolysis of CS2 are also presented compared with the results of the muon chemistry.

  • STUDY OF RADIATION-INDUCED REACTION IN LIQUID CARBON-TETRACHLORIDE BY MEANS OF PICOSECOND PULSE-RADIOLYSIS

    M WASHIO, Y YOSHIDA, N HAYASHI, H KOBAYASHI, S TAGAWA, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   34 ( 1 ) 115 - 120  1989

     View Summary

    Pico- and nano-second pulse radiolysis was applied to the study of the radiolysis of carbon tetrachloride (CCl4). In the u.v.-region, two different absorbing species were observed by using the twin linac pulse radiolysis technique. The component decays within 100 ps and the other component has a very long lifetime (about 100 ns). This long lifetime component has been reported in previous work. The absorption band of the very short lifetime component is broader than that of the long lifetime component in the u.v.-region. The growth of the absorption was measured very precisely using the twin linac pulse radiolysis and the analysis was carried out using the analytical solution of the Smoluchowski equation. Exponential function (R(r, r0) = (1/r0) exp (-r/r0)) as the initial distribution function of the geminate ion pair gives a better fit than the gaussian.

  • PULSE-RADIOLYSIS STUDIES ON LIQUID ALKANES AND RELATED POLYMERS

    S TAGAWA, N HAYASHI, Y YOSHIDA, M WASHIO, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   34 ( 4 ) 503 - 511  1989

     View Summary

    Absorption spectra of alkane radical cations, alkane excited states, and alkyl radicals and electrons in irradiated neat liquid alkanes at room temperature were assigned on subnanosecond and nanosecond time scale after an electron pulse. Two broad visible and near-infrared absorption bands of alkane excited states and radical cations, and UV absorption band of alkyl radicals were observed in neat n-alkanes. In neat cyclohexane and trans-decalin, very broad visible absorption band mainly due to alkane excited states and UV absorption band of alkyl radicals were observed. In neat neopentane and isooctane, visible absorption bands were not observed, although UV absorption bands of alkyl radicals were observed. The wavelengths of absorptive peaks of alkane radical cations and excited states become longer with increasing the number of carbon atoms of n-alkanes. The lifetimes of alkane radical cations become shorter with decreasing number of carbon atoms of n-alkanes and are shorter than those of electrons in neat alkanes. In irradiated ethylene-propylene copolymers, broad absorption bands of excited states and tail parts of absorption bands of radical cations and electrons were observed in visible and near-infrared region.

  • PULSE-RADIOLYSIS STUDIES ON THE TRANSIENT SPECIES OF AROMATIC-MOLECULES IN CHLORINATED-HYDROCARBON SOLUTIONS

    M WASHIO, S TAGAWA, K FURUYA, N HAYASHI, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   34 ( 4 ) 533 - 537  1989

     View Summary

    Pulse radiolysis has been carried out to identify the transient species produced by the pulsed electron irradiation for the several kinds of combination of the solutions of aromatic hydrocarbons (benzene, naphthalene and pyrene) in chlorinated hydrocarbons (CCl4, CHCl3, and CH2Cl2). Charge-transfer complex between aromatic ring and Cl atom has been observed for benzene solutions in above three solvents. Naphthalene monomer and dimer cation radicals have been observed for the solutions in CHCl3 and CH2Cl2. Monomer cation radicals of pyrene has been observed for the solution of pyrene in CCl4, and monomer and dimer cation radicals of pyrene have been observed for the solutions in CHCl3 and CH2Cl2.

    DOI

  • Pulse-radiolysis study on the yield of hydrated electron at elevated temperatures

    H. Shiraishi, Y. Katsumura, D. Hiroishi, K. Ishigure, M. Washio

    Journal of Physical Chemistry   92 ( 10 ) 3011 - 3017  1988

     View Summary

    A pulse-radiolysis technique has been used to estimate G(eaq -) at elevated temperatures up to 250°C. Observation in pure water indicated that absorbance at λmax of eaq - increases significantly with temperature, by 1.4 times in going from 20 to 250°C, when compared at supposedly equivalent times by which most of spur decay probably finishes at each temperature. This temperature dependence was considered to arise primarily from variation in G(eaq -) itself. In another series of experiments Cd2+ was used as an eaq - scavenger. The estimated G(Cd+) in a dilute Cd2+ solution was 3.5 and 3.8 respectively at 200 and 250°C in accord with the above estimation on the temperature dependence of G(eaq -). © 1988 American Chemical Society.

    DOI

  • Cis and Trans Olefin Radicals: Equilibrium and Photoisomerization

    T. W. Ebbesen, R. Akaba, K. Tokumaru, M. Washio, S. Tagawa, Y. Tabata

    Journal of the American Chemical Society   110 ( 7 ) 2147 - 2151  1988

     View Summary

    Electrochemical reduction of 1,2-bis(l-methyl-4-pyridino)ethylene dication gives the same reduction potentials (-0.53 and -0.72 V vs SCE in CH3CN) for both cis and trans isomers. Only the absorbance spectrum of the trans radical (∊(max) 57 000 M-1 cm-1 at 517 nm) is observed. However, by using pulse radiolysis the radicals of both cis and trans isomers are observed in aqueous solution. Although their absorbance spectra are similar, the extinction coefficients are very different. The cis radical is intrinsically stable but undergoes rapid electron exchange with the trans dication isomer. Cis and trans radicals equilibrate through electron exchange, the limiting rate constants in both directions of the equilibrium being 2 X 109M-1 s-1(cis to trans) and 3 X 108M-1 s-1(trans to cis). The photoisomerization of the olefin radicals is essentially one-way: the quantum yield for the cis radical is 0.2, while that of the trans is less than 0.01. © 1988, American Chemical Society. All rights reserved.

    DOI

  • LOCAL MOLECULAR-MOTION OF POLYSTYRENE MODEL COMPOUNDS MEASURED BY USING PICOSECOND PULSE-RADIOLYSIS .1. DIASTEREOISOMERIC STYRENE DIMERS - MULTICOMPONENT FLUORESCENCE DECAY CURVES, CONCENTRATION-DEPENDENCE, AND ALKYL END-GROUP EFFECT ON EXCIMER FORMATION

    H ITAGAKI, K HORIE, MITA, I, M WASHIO, S TAGAWA, Y TABATA, H SATO, Y TANAKA

    MACROMOLECULES   20 ( 11 ) 2774 - 2782  1987.11

     View Summary

    The dynamic process of intramolecular excimer formation in meso and racemic 4,6-di-phenylnonanes (PS2(propyl», diastereoisomeric dimer models of polystyrene, was investigated by using a picosecond pulse radiolysis technique. In dilute cyclohexane solution, the monomeric fluorescence of racemic PS2(propyl) decays single exponentially with a time constant of 11 ns, while that of meso PS2(propyl) was found to decay dual exponentially with time constants of 6 and 0.5 ns. These multicomponent fluorescence decays were found to be explicable by the local motion of conformational change. In conclusion, each time required for the conformational change (g + t/tg - ) → tt, (g + t/tg - ) ₒ g + g - , and g + g - → (g + t/tg - ) in meso PS2(propyl) is estimated to be 0.7, 2.5 and 6 ns, respectively, at room temperature. The proposition that fluorescence decay of diastereoisomeric dimers is influenced by molecular motion (conformational change) is also valid for explaining the profile of the transient fluorescence spectra of racemic PS2(propyl). The present result is an indication that multicomponent fluorescence decay observed in some polymer systems may be mainly due to the conformational change motion in meso dyads. The concentration dependence of the time constants of meso and racemic PS2(propyl) was also measured. In addition, an alkyl end-group effect on intramolecular excimer formation in styrene dimers is found to exist by comparing time constants of styrene dimers with methyl ends, propyl ends, and pentyl ends. © 1987, American Chemical Society. All rights reserved.

    DOI

  • RADIATION-INDUCED REACTIONS OF NITROANTHRACENE DERIVATIVES STUDIED BY GAMMA-RADIOLYSIS AND PULSE-RADIOLYSIS

    T NAKAYAMA, M KIMOTO, K HAMANOUE, H TERANISHI, M WASHIO, S TAGAWA, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   29 ( 5 ) 387 - 392  1987

     View Summary

    Gamma-radiolysis of 9-cyano-10-nitroanthracene (CN-NO 2 -A) in ethanol at room temperature gave rise to the formation of 9-cyanoanthracene, 9-cyano-10-aminoanthracene and 10-cyano-9-anthrol. Addition of triethylamine (TEA) enhanced the formation of the aminocompound, and 10-cyano-9-anthrol decomposed completely into 9-cyano-10-anthryloxy anion. Similar reactions might also occur for 9-benzoyl-10-nitroanthracene based on the comparison of the absorption spectral change with that for CN-NO 2 -A. In the presence of TEA, the transient spectra observed by pulse radiolyses at room temperature and gamma-radiolyses at 77 K were assigned to the radical anions of nitroanthracenes. Thus the formation of the aminocompounds was interpreted in terms of the electron transfer from the trapped electrons to nitroanthracenes followed by the protonation. In the absence of TEA, the new absorption bands were observed at 440-470 nm. We tentatively assigned these new absorption bands to the complexes of the radical anions of nitroanthracenes with the solvent radicals: the complexes may probably give rise to the formation of the final products other than the aminocompounds. © 1987.

    DOI

  • MECHANISM OF POSITRONIUM FORMATION IN MIXTURES OF FLUORINATED BENZENES AND NORMAL-HEXANE

    ZC ZHANG, Y ITO, M WASHIO, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   30 ( 1 ) 47 - 50  1987

     View Summary

    Positrinium yield (I3) in binary mixturesof benzene derivatives(p-difluorobenzene 1,2,4,5-tetrafluorobenzene, pentafluorobenzene, perfluorobenzene and p-xylene) in n-hexane has been measured. As additives all of the aromatic compounds have been found to enhance Ps yield in n-hexane, but the effect was unexpectedly smaller for 1,2,4,5-C6H2F4. It is proposed that there are at least three processes which lead to the enhancement: anti-recombination by scavenging excess electrons, anti-recombination by scavenging positive holes, and electron abstraction from excited molecular states. Addition of a small amount of n-hexane in the fluorinated benzenes resultedin a decrease in the Ps yield to a different degree which strongly depended on the number of flourine atoms substituted. Discussion is made on the Ps formation mechanism taking into account possible role of excited molecular states. © 1987.

    DOI

  • MECHANISM OF POSITRONIUM FORMATION IN MIXTURES OF FLUORINATED BENZENES AND NORMAL-HEXANE

    ZC ZHANG, Y ITO, M WASHIO, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   30 ( 1 ) 47 - 50  1987

     View Summary

    Positronium yield (I//3) in binary mixtures of benzene derivatives (p-difluorobenzene, 1,2,4,5-tetrafluorobenzene, pentafluorobenzene, perfluorobenzene and p-xylene) in n-hexane has been measured. As additives all of the aromatic compounds have been found to enhance Ps yield in n-hexane, but the effect was unexpectedly smaller for 1,2,4,5-C//6H//2F//4. It is proposed that there are at least three processes which lead to the enhancement: anti-recombination by scavenging excess electrons, anti-recombination by scavenging positive holes, and electron abstraction from excited molecular states. Addition of a small amount of n-hexane in the fluorinated benzenes resulted in a decrease in the Ps yield to a different degree which strongly depended on the number of fluorine atoms substituted. Discussion is made on the Ps formation mechanism taking into account possible role of excited molecular states.

  • SOME RECENT RADIOLYSIS WORKS BY MEANS OF A NEW PICOSECOND PULSE-RADIOLYSIS SYSTEM TWIN LINAC SYSTEM

    Y TABATA, H KOBAYASHI, M WASHIO, Y YOSHIDA, N HAYASHI, S TAGAWA

    JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES   101 ( 2 ) 163 - 169  1986.10

     View Summary

    A new picosecond pulse radiolysis &quot;Twin LINAC System&quot; has been constructed recently at Nuclear Engineering Research Laboratory at the University of Tokyo. The time resolution of the system is 20 ps and the system has a versatile capability for pulse radiolysis study. The outline of the facility is introduced. Some research carried out using the facility is presented. The examples are radiolysis of CCl4 and n-C21H44. © 1986 Akadémiai Kiadó.

    DOI

  • DESIGN AND CONSTRUCTION OF 18 MeV ELECTRON LINAC FOR PICO- AND NANO-SECOND BEAM.

    Hitoshi Kobayashi, Toru Ueda, Toshiaki Kobayashi, Masakazu Washio, Yoneho Tabata

    Journal of the Faculty of Engineering, University of Tokyo, Series B   38   51 - 57  1986.03

     View Summary

    An electron linac which can accelerate pico- and nano-second beam with an energy of 18 MeV has been designed and constructed. The linac can accelerate picosecond beam with a pulse width of approximately 10 ps and with an output charge of approximately 1 nc. The linac can accelerate 10 ns beam with an output current of 2 amps. The original 35 MeV linac is used as Cerenkov light source in Twin Linac Pulse Radiolysis System. The 18 MeV linac is used as irradiation source.

  • A special solvent effect of acetonitrile on the electron transfer from triethylamine to triplet anthraquinone

    K. Hamanoue, T. Nakayama, K. Sugiura, H. Teranishi, M. Washio, S. Tagawa, Y. Tabata

    Chemical Physics Letters   120   332  1985.10

    DOI

  • PULSE-RADIOLYSIS WITH PICOSECOND TIME RESOLUTION

    Y TABATA, H KOBAYASHI, M WASHIO, S TAGAWA, Y YOSHIDA

    RADIATION PHYSICS AND CHEMISTRY   26 ( 5 ) 473 - 479  1985

     View Summary

    A new absorption spectroscopy system with a time resolution of 20 picoseconds (ps) is described. Two parallel linacs which can accelerate single bunched beams (picosecond single beams) are used in the system. One linac of the two is used as an irradiation source and the other is used as a Čerenkov light source. The time interval between the irradiation source and the Čerenkov light source is changed by delaying the source beam for the Čerenkov light. The new system was named &quot;Twin Linac Pulse Radiolysis System.&quot; This details of the twin-linac pulse-radiolysis system and some of the experimental results are described. © 1985.

    DOI

  • STUDY ON SENSITIZED DEGRADATION AND CROSSLINKING OF POLYMERS BY MEANS OF PICOSECOND PULSE-RADIOLYSIS

    Y TABATA, S TAGAWA, M WASHIO, N HAYASHI

    RADIATION PHYSICS AND CHEMISTRY   25 ( 1-3 ) 305 - 316  1985

     View Summary

    Polystyrene and poly-α-methylstyrene can be crosslinked very effectively by introducing some functional groups to the polymer or in the presence of certain kind of solvents. In contrast, those polymers can be also degraded very effectively in the presence of oxygen in halogenated solvents. Some examples will be introduced, and the mechanism will be elucidated based upon data obtained by means of picosecond pulse radiolysis. © 1985.

    DOI

  • PICOSECOND PULSE SOURCES BY CERENKOV LIGHT GENERATED FROM FUSED-SILICA AND WATER

    S WAKITA, M WASHIO, Y SUZUKI, M HIRAI

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   24 ( 4 ) 502 - 505  1985

     View Summary

    Characteristics of the picosecond Cerenkov light pulse generated from fused silica in a shape of cone and from water in a conical vessel have been investigated in the wavelength range from 230 nm to 500 nm. The pulse durations are estimated to be 27.01k4.0 ps for fused silica and 30.0k7.0 ps for water. It is shown that the present Cerenkov light pulse can be used for measuring the luminescent decay time in the picosecond range in conventional materials such as PPO and TI+ monomers in KI crystals at room temperature. © 1985 IOP Publishing Ltd.

    DOI

  • PULSE-RADIOLYSIS STUDIES ON RADIATION-RESISTANCE OF EPOXY-RESIN

    S TAGAWA, M WASHIO, N HAYASHI, Y TABATA

    JOURNAL OF NUCLEAR MATERIALS   133 ( AUG ) 785 - 787  1985

     View Summary

    The mechanisms of radiation damage in epoxy resin, especially the primary processes, have been studied by a time-resolved spectroscopic technique (pulse radiolysis). The difference between the radiation resistance of aromatic and aliphatic amine curing epoxy resin is explained by internal radiation protection effects due to energy and charge transfer on the basis of the time-resolved spectroscopic data of reactive intermediate (excited states and ions) in an irradiated epoxy resin.

  • PULSE-RADIOLYSIS STUDIES ON RADIATION-RESISTANCE OF EPOXY-RESIN

    S TAGAWA, M WASHIO, N HAYASHI, Y TABATA

    JOURNAL OF NUCLEAR MATERIALS   133 ( AUG ) 785 - 787  1985

     View Summary

    The mechanisms of radiation damage in epoxy resin, especially the primary processes, have been studied by a time-resolved spectroscopic technique (pulse radiolysis). The difference between the radiation resistance of aromatic and aliphatic amine curing epoxy resin is explained by internal radiation protection effects due to energy and charge transfer on the basis of the time-resolved spectroscopic data of reactive intermediate (excited states and ions) in an irradiated epoxy resin. © 1985.

    DOI

  • A SPECIAL SOLVENT EFFECT OF ACETONITRILE ON THE ELECTRON-TRANSFER FROM TRIETHYLAMINE TO TRIPLET ANTHRAQUINONE

    K HAMANOUE, T NAKAYAMA, K SUGIURA, H TERANISHI, M WASHIO, S TAGAWA, Y TABATA

    CHEMICAL PHYSICS LETTERS   118 ( 5 ) 503 - 506  1985

     View Summary

    The photoreduction of anthraquinone (AQ) by triethylamine in acetonitrile was found to originate from two independent processes: The free radical anion of AQ and the exciplex between triethylamine and AQ were produced via the second and the lowest triplet states of AQ, respectively. © 1985.

    DOI

  • RED FLUORESCENCE FROM THE MEROCYANINE FORM OF SPIROBENZOPYRAN

    K HORIE, K HIRAO, MITA, I, Y TAKUBO, T OKAMOTO, M WASHIO, S TAGAWA, Y TABATA

    CHEMICAL PHYSICS LETTERS   119 ( 6 ) 499 - 502  1985

     View Summary

    A brilliant red emission observed for the colored form of 1,3,3-trimethyl-6′-nitrospiro[indoline-2,2′-[2H]benzopyran] both in solution and in polymer films was ascertained to be a fluorescence from its merocyanine form. The fluorescence lifetimes were measured to be 1.8 to 3.6 ns in polycarbonate and other polymer films and 230 ps in ethanol solution by picosecond laser flash and pulse radiolysis spectroscopies. © 1985.

    DOI

  • MULTICOMPONENT FLUORESCENCE DECAY AND MOLECULAR-MOTION OF DIASTEREOISOMERIC STYRENE DIMERS ON PICO-SECOND AND NANO-SECOND TIMESCALES

    H ITAGAKI, K HORIE, MITA, I, M WASHIO, S TAGAWA, Y TABATA, H SATO, Y TANAKA

    CHEMICAL PHYSICS LETTERS   120 ( 6 ) 547 - 551  1985

     View Summary

    The dynamic process of intramolecular excimer formation in meso and racemic 6,8-diphenyltridecanes (PS2), diastereoisomeric dimer model systems for polystyrene, was investigated by using picosecond pulse radiolysis. Monomeric flourescence of meso PS2 was found to decay with time constants of 3.5 and 0.5 ns. © 1985.

    DOI

  • PULSE RADIOLYSIS STUDIES ON THE MECHANISM OF THE HIGH SENSITIVITY OF CHLOROMETHYLATED POLYSTYRENE AS AN ELECTRON NEGATIVE RESIST.

    Y. Tabata, S. Tagawa, M. Washio

    American Chemical Society, Polymer Preprints, Division of Polymer Chemistry   25   287 - 288  1984.04

  • MECHANISM OF RADIATION-INDUCED CROSSLINKING AND CHAIN SCISSION IN RESIST POLYMERS

    Y TABATA, S TAGAWA, M WASHIO, S HAYASHI

    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY   187 ( APR ) 95 - POLY  1984

    Research paper, summary (international conference)  

  • PULSE-RADIOLYSIS STUDIES ON THE MECHANISM OF THE HIGH-SENSITIVITY OF CHLOROMETHYLATED POLYSTYRENE AS AN ELECTRON NEGATIVE RESIST

    Y TABATA, S TAGAWA, M WASHIO

    ACS SYMPOSIUM SERIES   266   151 - 163  1984

    Book review, literature introduction, etc.  

     View Summary

    Recently, chloromethylated polystyrene (CMS), a highly sensitive, high resolution electron resist with excellent dry etching durability, was developed. Very recently reactive intermediates in irradiated polystyrene, which is a starting material of CMS, have been studied and the transient absorption spectra of excimer, triplet states, charge-transfer complexes, and radical cations of polystyrene have been measured. The present paper describes the cross-linking mechanism of the high sensitivity CMS resist and compares it to that of polystyrene on the basis of data on reactive intermediates of polystyrene and CMS.

  • PICOSECOND PULSE-RADIOLYSIS STUDIES ON GEMINATE ION RECOMBINATION IN SATURATED-HYDROCARBON

    S TAGAWA, M WASHIO, H KOBAYASHI, Y KATSUMURA, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   21 ( 1-2 ) 45 - 52  1983

     View Summary

    The geminate recombination kinetics of the excess electron and the electron hole are discussed, based on time-resolved data on picosecond and nanosecond time scales. The recombination times of the excess electron and the electron hole are evaluated to be 3 ps for cyclohexane on the basis of the comparison between the experimental and the calculated results. The spin correlation decay of the geminate ion pairs and the triplet state formation before the spin correlation loss have also been discussed. The rapidly decaying species with very broad absorption spectra, which are similar to the absorption spectra of the cation radicals of saturated hydrocarbons, have been observed in neat saturated hydrocarbons in the sub-nanosecond and a few nanosecond time regions. The identification of the rapidly decaying species were not definitely made but those species are tentatively assigned to the excited states and/or the tail of the geminate cation radicals of saturated hydrocarbons. © 1983.

    DOI

  • PICOSECOND SINGLE ELECTRON PULSE FOR PULSE-RADIOLYSIS STUDIES

    H KOBAYASHI, T UEDA, T KOBAYASHI, M WASHIO, Y TABATA, S TAGAWA

    RADIATION PHYSICS AND CHEMISTRY   21 ( 1-2 ) 13 - 19  1983

     View Summary

    The S-band linac which can produce a picosecond single electron beam, has been operated since 1977. Several improvements of the linac have increased the reproducibility of picosecond single beam operation, the stability of average current of the output beams and the intensity of picosecond single beams. The application of the linac has been also investigated. Emission and absorption spectroscopy systems with a response of sub-nanosecond have been developed. © 1983.

    DOI

  • PULSE-RADIOLYSIS OF POLYSTYRENE AND BENZENE IN CYCLOHEXANE, CHLOROFORM AND CARBON-TETRACHLORIDE

    M WASHIO, S TAGAWA, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   21 ( 1-2 ) 239 - 243  1983

     View Summary

    Pulse radiolysis studies on pure carbon tetrachloride, pure chloroform, and their solutions containing polystyrene and benzene, and on polystyrene in cyclohexane solutions were carried out by using the pico- and nanosecond pulse radiolysis system. First direct observation of geminate processes in non polar liquid systems such as pure carbon tetrachloride and pure chloroform were made. In the radiolysis of pure carbon tetrachloride, it was observed that a transient species at 480 nm in formed by the geminate ion recombination process. In the case of chloroform, two absorption bands were observed at 330 nm and around 550 nm. The 550 nm band has not been clearly identified, but it can be considered that the absorption may be cationic species and the decay is related to the geminate recombination process. Pulse radiolysis of the polystyrene solution in cyclohexane showed the excimer absorption with lifetime of 20 ns. In the pulse radiolysis of polystyrene and benzene solutions in both carbon tetrachloride and chloroform, the charge transfer complex between polystyrene (or benzene) and Cl was observed in both solutions. In the pulse radiolysis of benzene in their solutions, the charge transfer complex between benzene and Cl was observed in both solutions. The lifetime of the charge transfer complexes between polystyrene and Cl is shorter than that of the charge transfer complexes between benzene and Cl, in both solutions. This implies that the disappearance of these species is due to proton transfer process. © 1983.

    DOI

  • PULSE-RADIOLYSIS STUDIES ON SHORT-LIVED INTERMEDIATES IN RADIATION-INDUCED POLYMERIZATION OF BULK STYRENE AND METHANOL STYRENE SOLUTIONS

    J SILVERMAN, S TAGAWA, H KOBAYASHI, Y KATSUMURA, M WASHIO, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   22 ( 6 ) 1039 - 1042  1983

     View Summary

    Primary processes of radiation-induced polymerization of bulk styrene at room temperature and effects of methanol have been studied by means of pulse radiolysis. Cationic intermediates such as the bonded dimer cation radical, which is the initiating species of radiation and photo-induced cationic polymerization, have been directly observed for the first time in bulk styrene. The rate constant of the reaction of the bonded dimer cation radical with a styrene monomer (trimerization and the first step of the cationic polymerization) has been directly determined to be the order of 106M-1sec-1. Methanol reacts with cationic and anionic species and enhances the absorption of radical species at 310 nm. © 1983.

    DOI

  • INTRAMOLECULAR EXCIMER FORMATION OF OLIGOSTYRENES FROM DIMER TO TRIDECAMER - THE MEASUREMENTS OF RATE CONSTANTS FOR EXCIMER FORMATION, SINGLET ENERGY MIGRATION, AND RELAXATION OF INTERNAL-ROTATION

    H ITAGAKI, K HORIE, MITA, I, M WASHIO, S TAGAWA, Y TABATA

    JOURNAL OF CHEMICAL PHYSICS   79 ( 8 ) 3996 - 4005  1983

     View Summary

    The emission properties of styrene oligomers from dimer to tridecamer have been investigated by picosecond pulse radiolysis at room temperature. The oligomers are precisely fractionated and are considered to be models of atactic polystyrene. The rate constant for excimer formation kDM of the order of 108 s-1, increases with increasing number of monomer units n for 2 ≤ n ≤ 8, then levels off at the value for polystyrene. The rate constant for singlet energy migration between adjacent chromophores in polystyrene was determined to be 3×1010 s-1 (∼30 ps). An average time of 7.2 ns was found to be necessary for two adjacent chromophores to assume the excimer conformation (g-t or tg - in a racemo dyad; tt in a meso dyad) from their initial equilibrium distribution of conformations. The present result is an indication that one may investigate the dynamics of internal rotation by photophysical techniques. Moreover, from a comparison of the results of photostationary measurements with those of transient methods, it is found that there is a discrepancy between them. This discrepancy is assumed to be caused by a molecular weight dependence either of the rate constant for the radiative deactivation from the excited monomer singlet kFM or of intramolecular self-quenching. © 1983 American Institute of Physics.

    DOI

  • GEMINATE RECOMBINATION KINETICS OF SOLUTE RADICAL IONS - SINGLET EXCITED-STATE FORMATION IN CYCLOHEXANE SOLUTIONS OF BIPHENYL

    S TAGAWA, M WASHIO, Y TABATA, H KOBAYASHI

    RADIATION PHYSICS AND CHEMISTRY   19 ( 4 ) 277 - 282  1982

     View Summary

    Transient absorption spectra of the solute anion, cation and triplet state and the solute fluorescence in the pulse radiolysis of 0.1 mole 1-1 biphenyl in cyclohexane were observed on a nanosecond timescale longer than 1 ns after a 20 ps pulse. The formation of the solute excited singlet state is mainly due to the geminate ion recombination reaction even in the high concentrated solutions. The decay of the solute ions obeys the reciprocal square root dependence on time longer than 10 ns from the end of a 10 ps pulse. The slope of this reciprocal square root plots agrees with the literature value on a longer timescale obtained by microwave absorption. The yield of free ions obtained from the intercept of the slope agrees also with the literature values obtained by the field clearing method. Ratio of the formation rate of the solute excited triplet state to the decay rate of the solute anion changes in a time range between 5 and 20 ns. It is very well correlated with a theoretical calculation of spin correlation decay of the germinate ion pairs by Brocklehurst, although the formation of the solute triplet state was observed even on a timescale shorter than 5 ns from the end of a 20 ps pulse, where loss of spin correlation is negligibly small. © 1982.

    DOI

  • The formation of solute excited triplet states via geminate ion recombination in cyclohexane solutions of biphenyl and pyrene on subnanosecond and nanosecond timescales

    S. Tagawa, Y. Tabata, H. Kobayashi, M. Washio

    Radiation Physics and Chemistry   19 ( 3 ) 193 - 196  1982

     View Summary

    The formation of the solute excited triplet states via geminate ion recombination observed for both biphenyl and pyrene solutions in cyclohexane has been studied by using a picosecond pulse radiolysis system for absorption spectroscopy with the time resolution of 8o ps. The ratio of the formation rate of the solute excited triplet state of the decay rate of the solute anion changes in a time range between 5 and 20 ns. It is very well correlated with the spin correlation decay of geminate ion pairs, which are initially paired with each other in a singlet state. The formation of the solute triplet state was observed even on a timescale shorter than 5 ns, although loss of spin correlation is negligibly small. © 1982.

    DOI

  • PICOSECOND PULSE-RADIOLYSIS AND LASER FLASH-PHOTOLYSIS STUDIES ON POLYMER DEGRADATION OF POLYSTYRENE AND POLY-ALPHA-METHYLSTYRENE

    S TAGAWA, W SCHNABEL, M WASHIO, Y TABATA

    RADIATION PHYSICS AND CHEMISTRY   18 ( 5-6 ) 1087 - 1095  1981

     View Summary

    Recently early events in photolysis of polystyrene (PSt) solutions in chloroform and in 1,4-dioxane have been made clear by using a nanosecond laser flash photolysis system (Nd-YAG: 265 nm) at Hahn-Meitner-Institut [1]. Early events in radiolysis of PSt solution have also been studied by using a picosecond pulse radiolysis system at Univ. of Tokyo [2]. In the present paper, the difference and the similarity between photolysis and radiolysis of PSt and poly-α-methylstyrene (P-α-MeSt) are discussed. Important results are as follows; 1. (1) In both cases of radiolysis and photolysis, strong absorptions of intramolecular excimer have been observed for PSt (λmax = 530 nm) and P-α-MeSt (λmax = 520 nm) solutions in dioxane and cyclohexane, in addition to the monomer and excimer fluorescence of these polymers. In these solutions, those polymers are hardly decomposed. 2. (2) In both radiolysis and photolysis, charge-transfer complexes (PSt+δ, Cl-δ or P-α-MeSt+δ, Cl-δ) have been observed for PSt and P-α-MeSt solutions in chloroform (CHCl3) and in carbon tetrachloride (CCl4). In these solutions, polymers are effectively decomposed. The charge-transfer complexes are precursors of macroradicals. 3. (3) The charge-transfer complexes are mainly produced from ion pairs (PST+...Cl- or P-α-MeSt+...Cl-) in the case of radiolysis and from exciplexes of excited polymer molecules with solvent molecules in the case of photolysis. 4. (4) Since the presence of oxygen is prerequisite to main chain cleavage of PSt in CHCl3 and in CCl4, it is important to note that oxygen is not involved in initial stages of the main process of macroradical formation. © 1981.

    DOI

  • PULSE-RADIOLYSIS STUDIES ON POLY(N-VINYLCARBAZOLE) CATION

    M WASHIO, S TAGAWA, Y TABATA

    POLYMER JOURNAL   13 ( 10 ) 935 - 938  1981

     View Summary

    Formation processes of poly(N-vinylcarbazole) cation (PVCZ+) and its reactivity were studied by a pulse radiolysis technique. In the formation of PVCZ+, the charge transfer from a solvent or additive cation radical plays an important role. Once formed, the PVCZ+ is stabilized. This stabilization makes the ion recombination reaction rate smaller by a factor of about 5 compared with the monomer cation. The cation scavenging reaction is also affected by this stabilization, and PVCZ+ is only scavenged by certain compounds of appreciably low ionization potential (for example; N, N, N′, N′-tetramethylbenzidine). The rate constant for the scavenging reaction was estimated to be about 3×109 M−1 s−1. © 1981, The Society of Polymer Science, Japan. All rights reserved.

    DOI

  • DIRECT OBSERVATION OF THE KINETIC-BEHAVIOR OF A CHARGE-TRANSFER REACTION ON THE CATION-SCAVENGING REACTION FOR CATION RADICALS OF N-VINYLCARBAZOLE AND N-ETHYLCARBAZOLE BY USING A PULSE-RADIOLYSIS TECHNIQUE

    M WASHIO, S TAGAWA, Y TABATA

    JOURNAL OF PHYSICAL CHEMISTRY   84 ( 22 ) 2876 - 2879  1980

     View Summary

    The cation-scavenging reaction has been directly observed by using the pulse radiolysis method for cation radicals of both N-vinylcarbazole (VCZ+·; the initiating species of radiation-induced cationic polymerization of VCZ) and N-ethylcarbazole (EtCZ+·, nonpolymerizing model compound) in order to elucidate the role of inhibitors in radiation-induced cationic polymerization. The rate constants for the reactions of VCZ+· with triethylamine, diphenylamine, and dimethylaniline in nitrobenzene solution have been determined to be 1.3 × 109, 2.0 × 109, and 3.9 × 109 M-1 s-1, respectively, which are almost the same as those for EtCZ+· with these three scavengers. © 1980 American Chemical Society.

    DOI

  • Picosecond time-resolved fluorescence studies of poly(N-vinylcarbazole) using a pulse-radiolysis technique

    Seiichi Tagawa, Masakazu Washio, Yoneho Tabata

    Chemical Physics Letters   68   276 - 281  1979.12

     View Summary

    The formation processes of two distinct excimers of poly(N-vinylcarbazole)(PVCZ) have been directly observed by using a picosecond single-pulse radiolysis system with 10 ps time resolution. The primary processes of radiation-induced excitation in the polymer solutions have been studied. A so-called second excimer (λmax of fluorescence = 375 nm) of PVCZ is almost completely formed immediately after a 10 ps electron pulse. Most of the sandwich-type excimer (λmax of fluorescence = 420 nm) is formed in several nanoseconds. Most of the second excimer was confirmed to be formed directly in preexisting sites. Most of the sandwich-type excimer was confirmed to be formed through structural change of the excited carbazolyl and the ground-state carbazolyl chromophore to the sandwich conformation. Both the concentration of the preexisting trap sites and the efficiency of energy migration along the polymer chain before relaxation or solvation of the excited state are considered to be most important in the formation of the second excimer. Most of the primary excited states of PVCZ in irradiated toluene solutions of PVCZ are formed immediately after the 10 ps electron pulse. These very fast formation processes of excited states of solute molecules agree with the recent experimental results observed in irradiated hydrocarbon solutions of aromatic molecules in the picosecond time domain. © 1979.

    DOI

▼display all

Industrial Property Rights

  • 電解質膜、膜電極接合体、および燃料電池

    6137569

    土田 亮太, 巽 貴浩, 吉川 妙子, 坪倉 英裕, 平岩 郷志, 大島 明博, 鷲尾 方一

    Patent

  • 積層体およびその製造方法

    6030191

    鷲尾 方一

    Patent

  • 積層体およびその製造方法

    5770349

    鷲尾 方一

    Patent

  • 電解質膜、膜電極接合体、燃料電池、及び電解質膜の製造方法

    6068939

    鷲尾 方一, 大島 明博, 土田 亮太, 巽 貴浩, 吉川 妙子, 坪倉 英裕, 平岩 郷志

    Patent

  • 微細構造体及びその製造方法

    鷲尾 方一, 大山 智子, 大久保 聡, 高橋 朋宏, 小林 亜暢

    Patent

  • 積層体およびその製造方法

    5769942

    鷲尾 方一

    Patent

  • 光陰極高周波電子銃、および光陰極高周波電子銃を備えた電子線装置

    5544598

    坂上 和之, 鷲尾 方一

    Patent

  • 高分子材料の微細構造形成方法、微細構造体

    鷲尾 方一, 大久保 聡

    Patent

  • 膜電極接合体、電解質膜及びこれらを用いた燃料電池

    大島 明博, 白木 文也, 大島 雄二, 鷲尾 方一

    Patent

  • 木材の表面処理方法

    鷲尾 方一, 大島 明博, 三浦 喬晴

    Patent

  • 電場処理装置

    4932260

    鷲尾 方一, 大島 明博

    Patent

  • 廃プラスチックの脱塩素処理方法、該処理装置および該処理設備

    4253746

    鷲尾 方一, 伊藤 政幸

    Patent

  • 近接X線リソグラフィの描画方法

    鷲尾 方一, 豊田 英二郎

    Patent

  • フッ素含有ポリマーおよび摺動部材

    濱 義昌, 大島 明博, 鷲尾 方一, 森 有一

    Patent

  • 近接X線リソグラフィのパターン描画方法およびマスク

    藤田 愛, 豊田 英二郎, 鷲尾 方一

    Patent

  • 放射線測定用の照射材及び放射線測定装置並びに放射線測定方法

    4162079

    鷲尾 方一, 大島 明博

    Patent

  • 高分子電解質膜

    3817213

    鷲尾 方一, 大島 明博, 佐藤 康平

    Patent

  • パターン描画方法、マスクおよびマスク製造方法

    鷲尾 方一, 豊田 英二郎

    Patent

  • ガンマ線の飛来方向の二次元精密計測方法及び装置

    鷲尾 方一, 小寺 正俊

    Patent

▼display all

Research Projects

  • High Quality X-ray Generation with 10 MW Self-Resonating Enhancement Optical Cavity

    Project Year :

    2019.04
    -
    2024.03
     

  • Establishment of design principle and basic technology for next generation medical high temperature superconducting skeleton-cyclotron

    Project Year :

    2018.06
    -
    2023.03
     

  • 次世代医療用高温超伝導スケルトン・サイクロトロンの設計原理・開発基盤の確立

    Project Year :

    2018.04
    -
    2022.03
     

  • 小型高輝度X線源のためのレーザーコンプトン散乱クラブ衝突化の実現

    Project Year :

    2018.04
    -
    2021.03
     

     View Summary

    レーザー光と電子ビームを衝突させ、より高エネルギーのX線光子を発生するレーザーコンプトン散乱において、衝突角に開きがあるような状況下においても理想的な正面衝突に近づけるために電子ビームに傾きを付与した状態で衝突を行う。このような衝突方法をクラブ衝突と呼んでおりルミノシティの増大が期待できる。昨年度、衝突用レーザーシステムの一旦の完成を遂げたものの、メインアンプであるThin-disk再生増幅器のモードプロファイルの安定性に課題を残す結果となっていた。今年度においては共振器構造を見直し、光が往復するリニア型から光が周回するリング型への開発を行った。リング型にすることで増幅光のモードプロファイル改善だけでなく、戻り光が発生しなくなるというメリットもある。リニア型の開発では戻り光によってシード系の損傷を経験し、修復が必要になるという手戻りを幾度か経験した。リング型ではミラー枚数が増えたが最大11mJの出力を確認することに成功した。ビーム品質を表すM2は水平垂直の両方向においておよそ1.5という測定結果を得ることに成功し、Thin-diskの利点である高いビーム品質とミリジュール級の増幅を両立することに成功した。ルミノシティ及びクラブ衝突による増大率の双方を高めるために衝突点においてレーザーをできる限り集光することが求められるため、ビーム品質は極めて重要である。これらを70cm×130cmの小型で移動可能な光学台に構築できた。回折格子対によるパルス圧縮では、折り返しミラーを平面ミラーからコの字型のミラーに置き換えることで往復の光路長を同一にした。オートコリレータによるパルス幅計測で1.5ピコ秒まで圧縮することに成功した。加速器との同期においては基準信号を119MHzから714MHzにし、チラーを別室配置することで外乱を低減した。結果、数ピコ秒の同期精度を得ることに成功した。電子ビームの高品質化、レーザーの大出力化に成功している。特にレーザーの安定性確保が実現できたので、最終年度に大きな成果が見込める。加速器とレーザーの同期について、可能な限りジッターを最小化するための方策を予備的に試験実施しており、2020年度にはこのシステムを用いて原理実証を達成できると考えている

  • Study of gamma-ray generation by using self-resonating enhancement optical cavity

    Project Year :

    2013.04
    -
    2018.03
     

     View Summary

    A power enhancement optical cavity is a compelling means of realizing high laser power. However, a precise feedback system is necessary for maintaining the narrow resonance condition of the optical cavity; this has become a major technical issue in developing such cavities. We have developed a new approach that does not require any active feedback system, by placing the cavity in the outer loop of a laser amplifier. We demonstrated the CW operation of the new system. The effective finesse of the cavity was measured to be 394,000, and the laser power stored in the cavity was approximately 187,000 times greater than the incident power to the cavity. The stored power was stabilized with a fluctuation of 1.7%, and we confirmed continuous cavity operation. This result has the potential to trigger an innovative evolution for applications that use optical resonant cavities. We also performed the first demonstration of a mode-locked pulse oscillation using the new system

  • BEUV light generation via multi-bunch short electron pulse pre-irradiation

    Project Year :

    2013.04
    -
    2016.03
     

     View Summary

    We have achieved the major subjects for obtaining the basic data aiming the highly efficient system of laser produced plasma (LPP). In this study, we have performed the high quality electron beam production system by using a photo-cathode rf-gun installed in Waseda University, and then we have developed the laser system with laser enhanced cavity in CO2 laser scheme. Through the development, we have obtained the data for LPP light under the pre-irradiation of multi-bunch electron beam in combination with the CO2 laser illumination. In the study, we have realized the stabilization of electron beam generation even in the multi-bunch scheme. Further, we have succeeded the construction of CO2 laser with the high finesses laser enhanced cavity. Finally, we have demonstrated the enhancement of LPP light up to 150% by using ten bunch electron beams in combination with 700mJ CO2 laser pulse with the duration of 400ns

  • Ultra-Compact Short Pulse and Coherent Teraherts (THz) Light Source Using Super-radiance

    Project Year :

    2011.10
    -
    2016.03
     

     View Summary

    Laser pulse energy of third harmonic generation of 800nm became 2.7mJ from 1.0mJ with 90 femtosec at gun cathode and the pulse was within 1.0% in regard to pointing and energy stability. After 90 fs electron single bunch and 4 micro-bunch train were generated and accelerated upto 8MeV, the characteristics of broadband and quasi-monochromatic radiation due to transition and Smith-Purcell radiation were measured. By tuning the micro-bunch spacing to the THz wavelength, it is possible to generate a narrowband coherent THz wave. Depending on whether an ideal Comb beam can be formed in the RF gun by high gradient acceleration, super-radiance peak power from the small wiggler (30cm) with five period reaches about 10MW peak power at 1pC/micro-bunch and about 100MW peak power at 10pC/micro-bunch. We confirmed the Super-radiation experimentally. Innovative THz light source applications can be developed soon through international cooperative network

  • Basic Research on Coherent Inverse Compton Scattering for High Power Soft X-ray Genetation

    Project Year :

    2010.04
    -
    2014.03
     

     View Summary

    In the present study, we have been carrying out the development of overall experimental and simulation studies by using our own Laser photo-cathode RF gun which is one of the best accelerators for achieving the purpose. One of the developments, we have studied the RF deflector cavity as the candidate for the converter of electron beam structure from thin beam in space to time domain. We have succeeded the development of micro-slit by applying the FIB technology to obtain the high aspect ratio structures. Finally, we have obtained micro-slit devices with the aspect ratio of 15 with the slit size is around 100 nm.We have demonstrated the micro-spacing electron beam by using micro-slits. Further, we have operated the RF deflector cavity for the space to time conversion of electron beam, and we have succeeded the establishment of the basic technology by controlling the micro-bunched electron beam using the developed technology for the realization of coherent Compton scattering

  • Development of a three dimensional four mirror optical cavity for laser-Compton scattering

    Project Year :

    2009.04
    -
    2013.03
     

     View Summary

    We made the design, fabrication, and performance test of a three-dimensional 4-mirror optical cavity for development of intense photon sources by laser-Compton scattering. We achieved the finesse of 4000 and average power of 2.6 kW in the cavity with the vertical laser beam spot size of 13±1μm in RMS at the laser-electron interaction point. As a result, we observed 124±1 photons with average energy of 24 MeV per beam crossing, which corresponds to the generation of 2.7×108photons per second

  • 高品質ビームの発生とその物性・反応研究への応用

    文部科学省 

    Project Year :

    2004
    -
    2008
     

  • 高品質ビームの発生とその物性・反応研究への応用

    文部科学省 

    Project Year :

    1999
    -
    2003
     

  • Development of Advanced Techniques for the Generation of High Luminosity X-ray Pulse by the Inverse Compton Scattering

    Project Year :

    2000
    -
    2002
     

     View Summary

    High quality electron beam generation by using a laser photo-cathode RF gun system has been performed The emittance value for the electron beam was very low enough for the Inverse Compton Scattering experiments. On the other hand, laser system for the collision with the electron beam was investigated We have achieved the stabilization of laser beam output intensity and timing to the local oscillator. The output stability was evaluated by the PSD (Power Spectrum Density) method and the value was less than 0.03%. The timing jitter was also evaluated by the same method and the value was less than 0.26ps. The pulse length of the electron beam has been measured by the new nondestructive technique named frequency analysis. The results show that the method is applicable for the measurement of electron pulse with pico-second renge. The simulation of the Inverse Compton Scattering has been performed and the optimization of the system has been realized As the results of the simulation, soft X-ray can be generated with the energy of several hundreds of eV, that is called as water windows, by the combination of the RF gun and the Nd : YLF laser. We have carried out the scattering experiment between 4.2 MeV electron beam and Nd : YLF laser, and obtained the clear X-ray signal from the X-ray, which has the time duration or 7. 7 ps with the energy of 300 eV

  • 高輝度X線発生のための逆コンプトン散乱プロセスの高度化に関する研究

    Project Year :

    2000
    -
    2002
     

  • 原子力分野への応用を目的とした自由電子レーザー技術の基礎研究

     View Summary

    東大原子力工学研究施設35MeVライナックで、自由電子レーザー特性に大きな影響を与える電子ビームパラメータの測定を行った。パルス平均のエネルギ分散は約2%であったが、パルス内で時間とともにピーク強度が減少し低エネルギ側にサブピークが成長するなどのスペクトルゆらぎが見られた。ビームダイナミクスを評価するコードを開発して検討した結果、この原因はクライストロン出力の約1%の出力変動にあることが知られた。周期数10,周期4cmのウィグラ磁石をライナックに設置し、電子ビームから生ずる自由電子レーザー自発放射光のスペクトル測定及び写真撮影を行った。中心が黄で外側にゆくにつれ波長が長くなり赤へ変化するリング状の放射スペクトルが観測された。さらに外側では2倍高調波である青・緑のリングが見られた。スペクトル測定結果は中心波長490nm,半値幅112nmであった。これらの結果を自発放射光発生メカニズムに基づく一様拡がりに加えてエネルギ分散・エミッタンス・磁場精度等に起因する非一様拡がりを考慮して評価し、理論値と良く一致すること及び自由電子レーザー性能の評価において考慮する必要があることを確認した。粒子シミュレーションに基づく自由電子レーザー解析コードを開発した。これを用いて実際のビームパラメータをとり込んだ発振計算を行い、ビームパラメータの増幅率に与える効果及び立ち上がりから飽和に至る過渡過程の特性を検討した。エネルギ分散の効果は飽和までの時間の増加となってあらわれ、パルス内でレーザー発振させるためには増幅率等の設定にこの過渡過程を考慮する必要のあることが知られた。以上のとおり、各種の実験・測定及び開発した解析コードによる検討を行い、自由電子レーザーの原子力分野への応用に係る基礎特性とその可能性を明らかにした

  • Realization of polarized positron micro-beam for investigation of spin structure of material

     View Summary

    We have sepetated the study in two steps, namely fundamental development of each technical items and practical usage of these items to achieve the goal of the project. Since various technical matters are related with generation of polarized slow positron-beams, we consider that the best way to complete the micra-beams of the polarized positrons is to make first precise studies of each component of the positron generation system :1) Understanding of spin motion in electric and magnetic fields.2) Generation of high intensity polaraized positron beams.3) Completion of beam vunching system.4) Development of the Wien filter.5) Establishment of the mesuring method for the positron polarization.6) Establishment of the mesuring method for p6sitron beam profile.7) Construction of multi-gamma-ray spectrometer.8) Study of production mechanisms of positorons.If these items are well understood, we will be able to construct the micra-beams of the polarized positrons without difficulties. It may be concluded that we have attained good results for all these matters. In particular, we achieved fur better results than initially expected

  • Generation of high intensity, multi-bunch polarized positron beams

     View Summary

    Studies at BNLIn order to attain laser-electon interaction with high luminosity, we constructed a Compton chamber in which laser is strongly focused and makes head-on collisions with electron. In October, 2000, we achieved the highest peak intensity of back scattered X-rays, 7x10^8 photons/sec in the collision of CO_2 laser with 60 MeV electrons. We have also developed plasma channel in which Compton scattering takes place for the laser beam confined in the channel. Thus the interaction length is elongated, resulting in the increase of the back scattered X-rays. We have successfully fablicated the plasma channel of 2 cm in length and 300 μm in radius having low density(10^<17>/cm^3).Studies at KEKWe have been pursuing systematic studies on polarized positron productions through Compton scattering and pair creation processes. Gamma-rays of 2x10^5/pulse was created in Compton scattering of a 532 nm laser light off the 1.28 GeV electron. We also have made the conceptual design of the polarized positron beam for JLC which requires highly intensive positron beams with the intensity of 10^<10> e^+ /pulse and a complicated multibunch structure, i.e. 95 pulses with the time interval of 2.8 ns repeating 150 Hz. It is found that positrons 3x1^<10> /pulse can be generated using the electron beams of 5.8 GeV with the intensity of 5x10^<10> /bunch and 50 peices of CO_2 lasers

  • Radiation Generation and Particle Acceleration using Photonic Crystal

     View Summary

    Photonic band-gap crystals are regular array of materials with different diffractive indices. Their lattice constants can be on the order of laser wavelengths. Two experiments were performed which try to apply the crystals to accelerators.One is the Smith-Purcell radiation generation. It is expected that electron beams can generate this radiation if they run parallel to the lattice surface within the distance of the lattice constant. Experiments used a two-dimensional crystal manufactured in the university laboratory and the 35MeV linac of ISIR, Osaka University. We expected the radiation whose (k,ω) characteristics corresponding to the intersection of beam dispersion and band lines on the Brillouin diagram of the crystal. We, however, observed much more radiations than expected. We consider that this is mainly because the beam size, 〜5mm, was much larger than the crystal lattice, <1μm.Another experiment is the acceleration of electrons using longitudinal electric fields of lasers. Core of the photonic crystal fiber guides laser pulses, if their wavelength is in the band-gap of the crystal. The longitudinal fields are supported in the fiber core. A 700GW 800nm 50fs laser pulse experimentally produced up to 2MeV electrons from AIR-800 fiber, product of Crystal Fibre Inc.. The transparency of the fiber for the 800nm laser was 〜1/10 of the value on the catalog. The acceleration gradient was smaller than the calculation by the order of 3

  • Development of Soft X-ray Mcroscope though the Inverse Compton Scattering

     View Summary

    The research has been concentrated on the highly sophisticated generation system of the soft X-ray with the energy range of 200-500 eV through the inverse Compton scattering between high quality electron beam and highly stabilized Nd : YLF laser light. High quality electron beam has been obtained from laser photocathode RF gun with specially designed for this project. On the other hand, highly stabilized Nd :YLF laser system is used for the generation of electron beam ( by 4^<th> harmonics of ND : YLF fundamenta1)and collision (by fundamental of Nd :YLF) experiments. The quality of electron beam has been measured by double slit scan technique for relatively low energy electron beam. The emittance of the electron beam is achieved to 3mm mrad, which is one of the lowest records for RF accelerated electron. The stability of laser light against to the local oscillator has been achieved to 0.26 ps. The energy of laser light per pulse has been obtained around 30mJ. The development of collision chamber is also successfully carried out. As the results, very precise measurements of soft X-ray with very low level noise have been realized. By using the system, the electron beam size measurements at the collision point and the dependence of collision angel for generated X-ray photons are demonstrated. The X-ray focusing system with specially designed zone plate is also developed

  • Research for Hybrid System comprised Laser Super Cavity and Off-Axis Parabolic Reflective mirrors toward International Linear Collider

     View Summary

    We have developed two kind of optical cavities which consist of several high reflectivity mirrors. These optical cavities can accumulate nJ or uJ laser pulse and enhance the pulse energy by about 1000 in the cavity. Also, we can make several um waist or laser interference pattern (pitch~500nm) at the center of the cavity. Based on inverse Compton scattering between laser pulse and high energy electron beam, we are measuring micron beam size or sub-micron beam size at accelerator test facility (ATF). Compact optical cavity laser wire and high power pulse laser oscillator are under developing

  • Imaging Technology Development of Living Object by Means of Inverse Compton Scattering

     View Summary

    Multi-bunch electron beam has been realized using specially developed multi-pulse laser system with Nd:YLF 4^<th> harmonics. The multi-pulse collision laser for the generation of high luminosity X-rays via inverse Compton scattering has been succeeded and the multi-pulse X-ray was achieved. In the study, we have some preliminary results to obtain the X-ray images of organs.

  • A study on microplanar beam radiation therapy at high energy X rays(≧1MeV)

     View Summary

    A study on microplanar beam radiation therapy(MRT) has demonstrated the following points : for the animal study at SPring-8, alignment of a collimator is very important to obtain a symmetrical beam profile for irradiation ; hypoxic fraction of tumor cells after MRT treatment was increased, which may explain the selective killing of tumor cells by MRT ; as for a beam width, narrow beam was more effective than wider beam, which suggests that an appropriate beam width must be exist ; and for the X-ray energy, high energy such as 1 MeV was not applicable and the most effective energy will be in the range of 100-250 keV

  • 異種界面接合を基盤とする高分子光運動材料の構築

     View Summary

    本研究課題では,液晶の分子構造,相状態,分子配向や高分子の架橋密度など種々の項目を検討し最適化するとともに,電子線架橋,光架橋,精密重合などの手法を駆使し様々な基材フィルムとの強固な異種界面接合を形成することにより,高性能光運動材料の構築を目的としている。本年度は,高性能高分子光運動材料の構築において必要不可欠である駆動原理探求を目的として,種々の架橋液晶高分子を合成するとともに,分光法および力学物性評価法を用いて,分子レベルから巨視的レベルまでメカニズムを検討した。架橋液晶高分子におけるアゾベンゼンの影響を結合位置および濃度について詳細に調べたところ,架橋部位にアゾベンゼンを20%程度含む場合に最も高い発生応力を得られることが明らかとなった。光運動挙動は,分子構造,分子の初期配向,異性化挙動,温度,光強度,光照射時間などに大きく依存し,アゾベンゼンの光異性化を分子配向変化へ増幅するプロセスが極めて重要であることがわかった。材料形状の変化についても検討を行った。より自由度の高い光運動材料を目指して繊維状の架橋液晶高分子を作製し光照射を行ったところ,照射方向に応じて三次元的な光運動を誘起できた。一方,アゾベンゼン液晶高分子とPVAを交互にスピン塗布した膜を作製したところ,従来と異なる光屈伸挙動を観察できた。新たな基材の開発および異種界面接合の形成についても検討を進めた。塩化コバルトを有機アルミニウムで活性化した触媒系を用いて少量のホスフィン共存下ブタジエンの重合を行うことにより,結晶性のシンジオタクチック1,2-連鎖と非晶性のシス1,4-連鎖からなるマルチブロック共重合体の合成に成功した

  • Fabrication of Multi Nano-array Electrodes with High Aspect Ratio Using Quantum Beam Irradiation

     View Summary

    The precision nano/ micro-fabrication of perfluorinated polymers including crosslinked one was carried out using various ion beams. Then, the sample which functionalized by graft polymerization and supported the silver ion was prepared. The direct reduction in the solid phase was performed by the quantum beam irradiation, and the obtained materials were analyzed with SEM-EDX and XPS. As results, the pure silver nanoparticle has been detected. Moreover, the array electrode with 60. m square can produce. It is succeeded that 800nm-width structures would be fabricated by direct patterning

▼display all

Specific Research

  • ヨウ化銀固定グラフト繊維の過冷却防止能を利用する氷凍結に必要なエネルギーの最小化

    2019   斎藤恭一

     View Summary

     放射線グラフト(接ぎ木)重合法という高分子修飾手法を使って、ナイロン繊維を出発材料にして物質分離機能をもつ繊維を開発した。具体的には、放射線を照射してナイロン繊維上にラジカルをつくり、そこからエポキシ基をもつビニルモノマーをグラフト重合させた。 本研究では、過冷却現象を制御できる材料として、ヨウ化銀固定およびタンニン酸固定繊維を、放射線グラフト重合法を適用して作製し精製水の凍結挙動を調べ、特にヨウ化銀固定繊維において、顕著な凍結挙動の違いに関する知見を得た。

  • コヒーレントEUV光による高分子アブレーション過程の解明と微細構造形成

    2016   坂上和之, 東口武史

     View Summary

    本研究では、コヒーレンスを持つEUV光(波長13.5nm)を利用した照射試験を実施した。具体的にはパルス幅が7~10 psのEUVビームの照射試験を実施するにあたり、量子科学技術研究開発機構(量研機構:QST)関西光科学研究所のEUVビーム装置を用い,EUV光の強度を変化させるため、光ビームラインに適切な厚さのZrフィルターをセットし、アブレーションの閾値を求めた。その結果、single shotの実験においては、どちらの高分子についてもそのアブレーション閾値は3-4mJ/㎠と非常に低い値となった。

  • 逆電流・電圧耐性のある低加湿運転可能な高出力固体高分子形燃料電池の開発研究

    2010  

     View Summary

     固体高分子型燃料電池(PEFC)の長期発電のためには、発電性能を低下させる種々の要因について詳細に検討する必要がある。本研究では、アニオン交換基(-OH)によるヒドロキシラジカルの生成を抑制する事を目指して、ナフィオン分散液とアニオン交換樹脂の微粒子をブレンドした電解質膜(NA)を作製し、FENTON試薬を用いて当該電解質膜を劣化させた後、試料の特性を評価した。また更に、低加湿運転を目指した傾斜機能を持つ固体高分子型燃料電池システムをイオンビーム等のエネルギー付与の不均一性を利用して作製し、その特性を評価した。 まず、アニオン交換樹脂を導入した系については、種々の濃度のアニオン交換樹脂含量の試料を作製しフェントン試験後の重量減少及び溶出したイオンの種類と濃度を測定した。この系においては、アニオン交換樹脂のパウダーの粒子径がナフィオン分散液に比べ大きいため、膜の劣化に伴い、予想より多い重量減少を確認した。すなわち、アニオン交換樹脂が当初の役割を果たさず、母体であるナフィオンとの相溶性の悪さにより、膜の劣化とともに流失したと判断できた。このことより、アニオン交換樹脂の粒子径を少なくともナフィオン分散液と同等にすべきであるという示唆が得られた。一方低加湿運転を実施可能とするために、アノードからカソードにかけて傾斜機能を与えた電解質膜を合成し、プロトン伝導性について検討した。この場合には、FEP(テフロンとヘキサフルオロプロピレンの共重合体)にカチオン交換基をイオンビームのエネルギー付与の深さ方向への不均一性を利用して、適切な傾斜機能導入し、詳細な試験を行った。その結果、プロトンの移動メカニズムがビークル機構よりホッピング機構が大きく寄与している膜の合成に成功した。これにより、相対湿度0~16%の低加湿条件で、従来の性能を上回る電解質膜の合成に成功した。今後は、当初より検討しているヒドロキシラジカル抑制のためのアニオン交換基の導入方法について更に検討を加える事で真に実用可能な新規の高性能電解質膜が合成できるものと考えている。

  • 逆電流耐性を有する傾斜機能型ハイブリッド電解質膜の開発研究

    2009  

     View Summary

     これまで我々は、電子線グラフト重合法により固体高分子形燃料電池用のカチオン交換膜を開発してきた。さらに作製したカチオン交換膜を微粒子化し市販のNafion&reg; 分散液と混合してハイブリッド電解質膜を成形することで,発電性能の向上が得られることが分かった。しかしながら,得られたハイブリッド膜は耐酸化性に課題を残していた。そこで,本研究ではカチオン交換膜にアニオン交換樹脂を少量添加することによって,ヒドロキシラジカルによる酸化劣化の抑制を検討した。開発したカチオン/アニオン交換基を有するハイブリッド電解質膜の基礎物性と,アニオン交換樹脂を含有させたことによる発電性能への影響を評価した。 具体的には、アニオン交換樹脂アンバーライト(オルガノ株式会社製)を粉砕し,Nafion&reg;分散液に加えた混合液を用意した。得られた混合液を超音波振動処理することで充分に撹拌させたあと,溶液をシャーレに移し,室温乾燥および熱処理(120 ℃,10 min,真空)をすることでハイブリッド膜(NA)を作製した。添加粒子の重量割合が1, 5 wt%であるハイブリット膜をそれぞれNA-1%,NA-5% とし,Nafion&reg;分散液のみで作製したNafion-cast 膜を比較対象として用いた。作製したハイブリッド膜の基礎物性,および発電性能を測定した。発電のための膜・電極接合体(MEA)は,0.1 mlのNafion&reg; 分散液を塗布・乾燥させてバインダー層を形成させたPt担持カーボン電極に,電解質膜を挟み熱プレス(110 ℃,8 MPa, 3 min)することで作製した。作製したMEAをJARI標準燃料電池発電セルに組み込み,セル温度60 ℃で発電試験を行った。使用した水素および酸素ガスの流量は50 ml/minであり,水素ガスは室温加湿した(相対湿度: 16%)。リニアスイープボルタンメトリ法によりI-V特性を評価し,四極交流インピーダンス法により電池の内部抵抗を測定した。 その結果、従来のカチオン交換膜の性能と発電性能においてほぼ同等である膜が得られる事を確認した。またアニオン交換樹脂を5%添加した膜においてはOCVの工場も見られ、今後逆電流耐性のある膜の開発に向けた基礎的なデータを得る事ができた。

  • 燃料電池用部分フッ素化イオン交換膜の合成と機能評価

    2007  

     View Summary

    はじめにこれまで固体高分子型燃料電池用電解質膜として、放射線グラフト法により高性能で安価な部分フッ素化電解質膜の開発を行ってきた。開発された放射線グラフト膜は、電極-電解質膜界面にバインダーとして塗布するNafion&#61650;-dispersionとの物性が違うことで、電極-電解質界面の接着性が低下し、発電時に内部抵抗の要因となっていると懸念されている。そこで本研究では膜-電極界面の接着性改善を目的として、バインダーと放射線グラフト膜から成る新規ハイブリッド電解質膜の開発研究を行った。実験方法Teflon&#61650;FEP(フロン工業、膜厚25μm)に窒素気流中室温下において15kGyの電子線照射を行った。その後FEPにスチレンをグラフトさせ、反応後、クロロスルホン酸溶液を用いてスルホン化することでスルホン化FEPを得た。次に得られたスルホン化FEP (s-FEP)をミキサーミルで粉砕し、それを5%Nafion&#61650;-dispersionに分散させ熱処理を行うことによってハイブリッド電解質膜FNを得た。ここでFNにおいてs-FEP粒子の添加量を50wt%, 20wt%, 10wt%とし、それぞれFN50w%, FN20w%, FN10w%とする。また、s-FEP及びNafion&#61650;-dispersionのみで作製したNafion&#61650;-castと合わせて物性評価を行った。結果および考察得られた各PEMのイオン交換容量(IEC)と、AFMで測定した表面粗さRaを評価すると、IECの高いs-FEPをブレンドすることにより、その値はFN50w%(1.2meq/g), FN20w%(1.1meq/g), FN10w%(1.0meq/g), Nafion&#61650;-cast(0.9meq/g)の順になった。表面粗さRaはFN50w%(319nm), FN20w%(153nm), FN10w%(87nm)となった。これは、添加したs-FEPの粒径が22μmとNafion&#61650;粒子に比べて大きいために添加割合を増やすほど表面の凹凸が激しくなったためであると考えられる。それぞれの膜で作成した膜-電極接合体をセル温度60℃で発電させた結果、FNの系に関してはいずれもs-FEPよりも高い出力が得られ、その結果は高い順にFN10w%, FN20w%, FN50w%であった。特にFN10%の膜では、最高出力密度1W/cm2の高出力化に成功した。FNの系でs-FEPよりも高い発電性能が得られた理由は、バインダーと同じ成分を膜に添加したことにより膜-電極間の相溶性が高くなり、生成イオンが拡散しやすくなったためであると考えられる。しかしながら、s-FEP粒子の添加量を増やすと表面粗さが増大するため、添加量の少ないFN10w%の方がFN50w%よりも接着性が良好であり、FN10w%が最も高い発電性能を示したものと考えられる。

  • マルチバンチ・大出力レーザーフォトカソードRF電子銃の開発

    2002   濱 義昌, 柏木 茂

     View Summary

    フォトカソードRF-gunを用いた高品質電子ビーム生成とその応用について研究を行ってきた。陰極には、高量子効率のCs-Teを用いることにより、電子ビーム励起用レーザーの負荷を軽くし、低いエネルギーでシングルバンチからマルチバンチまで制御可能である。RF-gunにより生成した電子ビームのエネルギーは3~4 MeVで、その後、第一加速管(L0)において80MeVまで加速される。その際、電子ビームのエネルギー幅を1 %以下にすることができた。そのため、ビームロス0の状態で下流のLinacセクションでさらに1.28 GeVまで加速され、BT、DRを通過し、EXTセクションでビームを取り出すことができる。EXTセクションでは、これまで早稲田大学、KEK-ATF、都立大学の共同研究で進めてきているレーザーコンプトン散乱による円偏光ガンマー線及び偏極陽電子生成実証実験を行っており、14年度には、ガンマー線の偏極度を測定することに成功した。一方、喜久井町施設では、フォトカソードRF-gun単体の性能評価実験を行い、同時にこれまで確立してきたレーザーコンプトン散乱の技術を応用し、X線顕微鏡を目指した「水の窓」領域の軟X線生成を行った。RF-gun単体の性能評価実験では、スリットスキャン法によるエミッタンス測定の技術を確立した。軟X線生成実験では、フラッシュランプ励起によるレーザー増幅器を開発し、出力を増強した。その結果レーザー出力を10倍まで増幅することに成功した。そして、レーザーフォトカソードRF-gunによって生成した4 MeV程度の電子ビームと上記の増幅したNd;YLFレーザー光(波長1047 nm)を衝突させ、レーザーコンプトン散乱により、エネルギー約300eVの「水の窓」領域の軟X線を生成することに成功した。その際、RF-gunに照射している電子ビーム励起用のレーザーと衝突用のレーザーは、同じSeedレーザーから生成されており、同期をとる事が容易であり、全体のシステムが非常にコンパクトなものになっている。また、この軟X線のエネルギーは、窒素のK殻吸収端と炭素のK殻吸収端の間にあたり、さらに水に吸収されにくい性質を持つことから、軟X線顕微鏡への応用が期待されている。

  • 新規高輝度X線発生のための逆コンプトン散乱の高度化に関する研究

    2000   濱 義昌, 柏木 茂

     View Summary

     物質内部における超高速の物理化学反応の解明や、生体等のミクロなレベルで生きた状態での分析を行うためには、極めて特殊なX線が必要となる。即ち超高速の物理化学現象を直接観測するためには、超短パルスで高輝度なX線が、また生体の分析に関しては数100eVの領域における極めて質の良いX線が必要となる。 本研究ではこのような特殊なX線を極めて質の高い電子線パルスと高輝度レーザーとの間の逆コンプトン散乱によって発生させるシステムについての基礎的な検討を行ったものである。具体的には、現在開発を進めているレーザーフォトカソードRF電子銃から得られる電子線について系統的な研究を行い、達成可能な電子ビームの特性についての基礎データを得ることができた。また同時に衝突用のレーザー光についても単独運転時の出力及び時間安定性、更にRF場における安定性評価も実施し、本レーザー装置が我々の目的とするX線発生に利用できるかどうかの評価を行った。その結果、電子ビームについては、数nCの電荷量を持つパルス幅10psの電子パルスをエミッタンスを大きく損なうことなく、5MeVまで加速可能であることを確認した。またレーザー装置の出力安定度に関しては、±0.5以内の精度を得ることができ、更に時間ジッターについても0.29psという極めて安定な動作を確認した。その一方で大電力RF場においては、出力の不安定さが確認され、相応の電磁波シールドが必要となる事を確認した。 これらの装置を用いて発生できる短パルスX線について、計算機によるシミュレーションを実施し、以下のような性能を達成できる見込みを得た。即ち、1047nmの赤外レーザー光と5MeV電子の正面衝突により最大エネルギーとして480eV、衝突角度を変更する事で、窒素のk吸収端、及び炭素のk吸収端を挟むほぼ単色のX線を発生できる事を確認した。これにより、今後装置の実用化を通じ多岐にわたる物理現象の解明や生体反応の解明、更に超高速の動画撮影などへの応用が可能となり、物性及び物質科学、物理化学等の分野への大きな貢献が期待できる状況となった。

  • レーザー・RF間の高精度同期システムの基礎研究

    1998  

     View Summary

    超高速物理化学反応の解明は、新物質の創世や反応の制御、物質中での欠陥生成の総合的な理解等の面で非常に重要である。パルスラジオリシス法はこのような物理化学反応の基礎過程解明の有力な武器として知られているが、現状では反応の本質を議論するレベルにない。近年のパルスラジオリシスシステムでは、ポンプ源としてRF加速された電子、プローブとしてレーザーを用いている。基本的にレーザーー電子ビーム間の時間揺らぎは、レーザー光によって電子を発生させると同時に、電子発生に用いたレーザー光をプローブに利用することにより非常に小さくする事ができるはずである。しかし、過去の実験例では、この方式を用いても十分な精度が得られなかった。<BR>本研究では、このシステムのにおける同期及び時間分解能制御の基礎的な研究を実施し、以下に挙げるような成果を挙げた。 RF光電子銃から取り出される電子のバンチ長さ、エミッタンス、エネルギー分散はレーザー光のRF位相への入射タイミング及びレーザービームサイズにより大きく変化する。本研究成果からパルスラジオリシス実験を実施するための、詳細な条件を決定する事ができた。<BR>1.数ピコ秒程度の時間分解能を得る場合には、従来のシステムで実施可能であるが、レーザー光のパルス長を5ps程度とするとともに、RFへの入射位相を最大加速位相より20度程度を早いタイミングで入射する。このようにする事により、適切なバンチ長さの電子が得られ、しかも電子のエネルギーゲインも十分となり、精度の良い実験が可能となる。<BR>2.更に進めて1ピコ秒程度の時間分解能を得るためには、新しいシステムの導入が必要である事が分かった。この方式は、RF光電子銃の後段にエネルギー選別をしながら加速が可能なレーストラック型のマイクロトロンを設置するもので、このようにする事により、約1psの電子パルスを非常に狭いエネルギー分散で取り出す事ができる事を見出した。これにより、レーザー光と高度に同期した形で電子ビームを取り出す事が可能となる。なおこの方式の高度化により、加速電子とレーザー光の衝突による、フェムト秒X線パルスの発生も視野に入ってきており、更に進んだシステム開発の基礎を確立する事ができた。

▼display all

 

Syllabus

▼display all