2023/02/01 更新

写真a

アカイケ ヨウスイ
赤池 陽水
Scopus 論文情報  
論文数: 0  Citation: 0  h-index: 13

Citation Countは当該年に発表した論文の被引用数

所属
理工学術院 理工学術院総合研究所
職名
主任研究員(研究院准教授)
 

研究分野

  • 素粒子、原子核、宇宙線、宇宙物理にする実験

論文

  • Cosmic-ray Boron Flux Measured from 8.4 GeV/n to 3.8 TeV/n with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, G. A. de Nolfo, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Physical Review Letters   129 ( 25 )  2022年12月  [査読有り]

    DOI

  • SuperTIGER instrument abundances of galactic cosmic rays for the charge interval 41 < Z < 56

    Nathan Elliot Walsh, Yosui Akaike, Walter Robert Binns, Richard G. Bose, Terri J. Brandt, Dana L. Braun, Nicholas W. Cannady, Paul F. Dowkontt, Thomas Hams, Martin H. Israel, John F. Krizmanic, Allan W. Labrador, Richard A. Mewaldt, John W. Mitchell, Ryan P. Murphy, Georgia A. de Nolfo, Scott Nutter, Martin A. Olevitch, Brian F. Rauch, Kenichi Sakai, Makoto Sasaki, Garry E. Simburger, Ed C. Stone, Teresa Tatoli, John Ennis Ward, Mark E. Wiedenbeck, Wolfgang Zober

    ADVANCES IN SPACE RESEARCH   70 ( 9 ) 2666 - 2673  2022年11月

     概要を見る

    We report preliminary elemental abundance results from the 55-day long-duration-balloon flight of SuperTIGER (Super Trans-Iron Galactic Element Recorder) during the 2012-2013 austral summer. SuperTIGER measured the relative abundances of Galactic cosmic -ray (GCR) nuclei with high statistical precision and well resolved individual element peaks from 10Ne to 40Zr. SuperTIGER also made exploratory measurements of the relative abundances up to 56Ba. Although the statistics are low for elements heavier than 40Zr, we pre-sent, for the first time, relative abundance measurements of charges Z = 41 -56 with individual element resolution. GCR measurements up to 40Zr support a source acceleration model where supernovae in OB associations preferentially accelerate refractory elements that are more readily embedded in interstellar dust grains than volatiles. In addition, injection into the GCR for both refractory and volatile ele-ments appears to follow a charge dependence consistent with their grain sputtering cross sections. By extending the GCR measurement range past 40Zr, we can begin to further constrain these models. (c) 2022 COSPAR. Published by Elsevier B.V. All rights reserved.

    DOI

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  • Observation of Spectral Structures in the Flux of Cosmic-Ray Protons from 50 GeV to 60 TeV with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. de Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Physical Review Letters   129 ( 10 )  2022年09月

    DOI

  • CALET Search for Electromagnetic Counterparts of Gravitational Waves during the LIGO/Virgo O3 Run

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. de Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    The Astrophysical Journal   933 ( 1 ) 85 - 85  2022年07月

     概要を見る

    Abstract

    The CALorimetric Electron Telescope (CALET) on the International Space Station consists of a high-energy cosmic-ray CALorimeter (CAL) and a lower-energy CALET Gamma-ray Burst Monitor (CGBM). CAL is sensitive to electrons up to 20 TeV, cosmic-ray nuclei from Z = 1 through Z ∼ 40, and gamma rays over the range 1 GeV–10 TeV. CGBM observes gamma rays from 7 keV to 20 MeV. The combined CAL-CGBM instrument has conducted a search for gamma-ray bursts (GRBs) since 2015 October. We report here on the results of a search for X-ray/gamma-ray counterparts to gravitational-wave events reported during the LIGO/Virgo observing run O3. No events have been detected that pass all acceptance criteria. We describe the components, performance, and triggering algorithms of the CGBM—the two Hard X-ray Monitors consisting of LaBr3(Ce) scintillators sensitive to 7 keV–1 MeV gamma rays and a Soft Gamma-ray Monitor BGO scintillator sensitive to 40 keV–20 MeV—and the high-energy CAL consisting of a charge detection module, imaging calorimeter, and the fully active total absorption calorimeter. The analysis procedure is described and upper limits to the time-averaged fluxes are presented.

    DOI

    Scopus

  • CALET on the International Space Station: a precise measurement of the iron spectrum

    O. Adriani, Yosui Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, Caterina Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. de Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, Francesco Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Proceedings of Science   398  2022年05月

     概要を見る

    The Calorimetric Electron Telescope (CALET) was launched on the International Space Station in 2015 and since then has collected a large sample of cosmic-ray charged particles over a wide energy. Thanks to a couple of layers of segmented plastic scintillators placed on top of the detector, the instrument is able to identify the charge of individual elements from proton to iron (and above). The imaging tungsten scintillating fiber calorimeter provides accurate particle tracking and the lead tungstate homogeneous calorimeter can measured the energy with a wide dynamic range. One of the CALET scientific objectives is to measure the energy spectra of cosmic rays to shed light on their acceleration and propagation in the Galaxy. By the observation in first five years, a precise measurement of the iron spectrum is now available in the range of kinetic energy per nucleon from 10 GeV/n to 2 TeV/n. The CALET's result with a description of the analysis and details on systematic uncertainties will be illustrated. Also, a comparison with previous experiments' results is given.

  • Direct Measurement of the Nickel Spectrum in Cosmic Rays in the Energy Range from 8.8 GeV/ n to 240 GeV/ n with CALET on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, W. V. Zober

    Physical Review Letters   128 ( 13 )  2022年04月

     概要を見る

    The relative abundance of cosmic ray nickel nuclei with respect to iron is by far larger than for all other transiron elements; therefore it provides a favorable opportunity for a low background measurement of its spectrum. Since nickel, as well as iron, is one of the most stable nuclei, the nickel energy spectrum and its relative abundance with respect to iron provide important information to estimate the abundances at the cosmic ray source and to model the Galactic propagation of heavy nuclei. However, only a few direct measurements of cosmic-ray nickel at energy larger than ∼3 GeV/n are available at present in the literature, and they are affected by strong limitations in both energy reach and statistics. In this Letter, we present a measurement of the differential energy spectrum of nickel in the energy range from 8.8 to 240 GeV/n, carried out with unprecedented precision by the Calorimetric Electron Telescope (CALET) in operation on the International Space Station since 2015. The CALET instrument can identify individual nuclear species via a measurement of their electric charge with a dynamic range extending far beyond iron (up to atomic number Z=40). The particle's energy is measured by a homogeneous calorimeter (1.2 proton interaction lengths, 27 radiation lengths) preceded by a thin imaging section (3 radiation lengths) providing tracking and energy sampling. This Letter follows our previous measurement of the iron spectrum [1O. Adriani (CALET Collaboration), Phys. Rev. Lett. 126, 241101 (2021).PRLTAO0031-900710.1103/PhysRevLett.126.241101], and it extends our investigation on the energy dependence of the spectral index of heavy elements. It reports the analysis of nickel data collected from November 2015 to May 2021 and a detailed assessment of the systematic uncertainties. In the region from 20 to 240 GeV/n our present data are compatible within the errors with a single power law with spectral index -2.51±0.07.

    DOI PubMed

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  • Monte Carlo Study of Electron and Positron Cosmic-Ray Propagation with the CALET Spectrum

    Katsuaki Asano, Yoichi Asaoka, Yosui Akaike, Norita Kawanaka, Kazunori Kohri, Holger M. Motz, Toshio Terasawa

    ASTROPHYSICAL JOURNAL   926 ( 1 ) 5 - 5  2022年02月  [査読有り]

     概要を見る

    <title>Abstract</title>
    Focusing on the electron and positron spectrum measured with the Calorimetric Electron Telescope (CALET), which shows characteristic structures, we calculate the flux contributions of cosmic rays that have escaped from randomly appearing supernova remnants. We adopt a Monte Carlo method to take into account the stochastic nature of the appearance of nearby sources. We find that without a complicated energy dependence of the diffusion coefficient, simple power-law diffusion coefficients can produce spectra similar to the CALET spectrum, even with a dispersion in the injection index. The positron component measured with AMS-02 is consistent with a bump-like structure around 300 GeV in the CALET spectrum. One to three nearby supernovae can contribute up to a few tens of percent of the CALET flux at 2–4 TeV, while ten or more unknown and distant (≳500 pc) supernovae account for the remaining several tens of percent of the flux. The CALET spectrum, showing a sharp drop at ∼1 TeV, allows for a contribution of cosmic rays from an extraordinary event that occurred ∼400 kyr ago. This type of event releases electrons/positrons with a total energy more than 10 times the average energy for usual supernovae, and its occurrence rate is lower than one three-hundredth of the usual supernova rate.

    DOI

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  • CALET Observations during the First 5 Years on the ISS

    P. S. Marrocchesi, O. Adriani, Y. Akaike, Y. Asaoka, E. Berti, G. Bigongiari, M. Bongi, P. Brogi, A. Bruno, N. Cannady, C. Checchia, M. L. Cherry, G. Collazuol, A. W. Ficklin, T. G. Guzik, M. Ichimura, M. H. Israel, K. Kasahara, Y. Kawakubo, J. F. Krizmanic, A. M. Messineo, J. W. Mitchell, S. Miyake, M. Mori, N. Mori, H. M. Motz, K. Munakata, L. Pacini, F. Palma, P. Papini, B. F. Rauch, S. B. Ricciarini, T. Sakamoto, M. Sasaki, F. Stolzi, A. Sulaj, T. Tamura, S. Torii, J. P. Wefel, K. Yoshida, W. V. Zober

    Physics of Atomic Nuclei   84 ( 6 ) 985 - 994  2021年11月

     概要を見る

    The CALorimetric Electron Telescope CALET is collecting science data on the International Space Station since October 2015 with excellent and continuous performance. Energy is measured with a deep homogeneous calorimeter (1.2 nuclear interaction lengths, 27 radiation lengths) preceded by an imaging pre-shower (3 radiation lengths, 1mm granularity) providing tracking and 10-5 electron/proton discrimination. Two independent sub-systems identify the charge Z of the incident particle from proton to iron and above (Z<40). CALET measures the cosmic-ray electron + positron flux up to 20 TeV, gamma rays up to 10 TeV, and nuclei up to the PeV scale. In this paper, we report the on-orbit performance of the instrument and summarize the main results obtained during the first 5 years of operation, including the electron + positron energy spectrum and the individual spectra of protons, heavier nuclei and iron. Solar modulation and gamma-ray observations are also concisely reported, as well as transient phenomena and the search for gravitational wave counterparts.

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  • Measurement of the Iron Spectrum in Cosmic Rays from 10 GeV/n to 2.0 TeV/n with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, J. Link, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Physical Review Letters   126 ( 24 )  2021年06月

     概要を見る

    The Calorimetric Electron Telescope (CALET), in operation on the International Space Station since 2015, collected a large sample of cosmic-ray iron over a wide energy interval. In this Letter a measurement of the iron spectrum is presented in the range of kinetic energy per nucleon from 10 GeV/n to 2.0 TeV/n allowing the inclusion of iron in the list of elements studied with unprecedented precision by space-borne instruments. The measurement is based on observations carried out from January 2016 to May 2020. The CALET instrument can identify individual nuclear species via a measurement of their electric charge with a dynamic range extending far beyond iron (up to atomic number Z=40). The energy is measured by a homogeneous calorimeter with a total equivalent thickness of 1.2 proton interaction lengths preceded by a thin (3 radiation lengths) imaging section providing tracking and energy sampling. The analysis of the data and the detailed assessment of systematic uncertainties are described and results are compared with the findings of previous experiments. The observed differential spectrum is consistent within the errors with previous experiments. In the region from 50 GeV/n to 2 TeV/n our present data are compatible with a single power law with spectral index -2.60±0.03.

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  • Direct Measurement of the Cosmic-Ray Carbon and Oxygen Spectra from 10 GeV/ n to 2.2 TeV/ n with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, J. Link, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, F. Palma, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, S. Sugita, J. E. Suh, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Physical Review Letters   125 ( 25 )  2020年12月

     概要を見る

    In this paper, we present the measurement of the energy spectra of carbon and oxygen in cosmic rays based on observations with the Calorimetric Electron Telescope on the International Space Station from October 2015 to October 2019. Analysis, including the detailed assessment of systematic uncertainties, and results are reported. The energy spectra are measured in kinetic energy per nucleon from 10 GeV/n to 2.2 TeV/n with an all-calorimetric instrument with a total thickness corresponding to 1.3 nuclear interaction length. The observed carbon and oxygen fluxes show a spectral index change of ∼0.15 around 200 GeV/n established with a significance >3σ. They have the same energy dependence with a constant C/O flux ratio 0.911±0.006 above 25 GeV/n. The spectral hardening is consistent with that measured by AMS-02, but the absolute normalization of the flux is about 27% lower, though in agreement with observations from previous experiments including the PAMELA spectrometer and the calorimetric balloon-borne experiment CREAM.

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  • CALET on the International Space Station: The first three years of observations

    P. Brogi, P. Brogi, O. Adriani, O. Adriani, Y. Akaike, Y. Akaike, K. Asano, Y. Asaoka, Y. Asaoka, M. G. Bagliesi, M. G. Bagliesi, E. Berti, E. Berti, G. Bigongiari, G. Bigongiari, W. R. Binns, S. Bonechi, S. Bonechi, M. Bongi, M. Bongi, A. Bruno, J. H. Buckley, N. Cannady, N. Cannady, G. Castellini, C. Checchia, C. Checchia, M. L. Cherry, G. Collazuol, G. Collazuol, V. Di Felice, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, J. F. Krizmanic, J. Link, J. Link, P. Maestro, P. Maestro, P. S. Marrocchesi, P. S. Marrocchesi, A. M. Messineo, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, F. Palma, F. Palma, P. Papini, B. F. Rauch, S. B. Ricciarini, S. B. Ricciarini, K. Sakai, K. Sakai, T. Sakamoto, M. Sasaki, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, F. Stolzi, S. Sugita, J. E. Suh, J. E. Suh, A. Sulaj

    Physica Scripta   95 ( 7 )  2020年07月

     概要を見る

    The CALorimetric Electron Telescope CALET is a space instrument designed to carry out precision measurements of high energy cosmic-rays on the JEM-EF external platform on the International Space Station, where it has been collecting science data continuously since mid October 2015. In addition to its primary goal of identifying nearby sources of high-energy electrons and possible signatures of dark matter in the electron spectrum, CALET is carrying out extensive measurements of the energy spectra, relative abundances and secondary-to-primary ratios of elements from proton to iron, and even above (up to Z = 40), studying the details of galactic particle propagation and acceleration. An overview of CALET based on the data taken during the first three years of observations is presented, including a direct measurement of the electron+positron energy spectrum from 11 GeV to 4.8 TeV. The proton spectrum has been measured from 50 GeV to 10 TeV covering, for the first time with a single space-borne instrument, the whole energy interval previously investigated in separate sub-ranges by magnetic spectrometers and calorimetric instruments. Preliminary spectra of cosmic-ray nuclei are also presented, together with gamma-ray observations and searches for an e.m. counterpart of LIGO/Virgo GW events.

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  • CALET results after three years on the International Space Station

    Y. Asaoka, O. Adriani, Y. Akaike, K. Asano, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, J. Link, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, N. Opsina, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, V. Pal'Shin, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, S. Sugita, J. E. Suh, A. Sulaj, I. Takahashi, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Journal of Physics: Conference Series   1468 ( 1 )  2020年03月

     概要を見る

    The CALET (CALorimetric Electron Telescope) space experiment, which is currently conducting direct cosmic-ray observations onboard the International Space Station (ISS), is an all-calorimetric instrument optimized for cosmic-ray electron measurements with capability to measure hadrons and gamma-rays. Since the start of observation in October 2015, smooth and continuous operations have taken place. In this paper, we will give a brief summary of the CALET observations ranging from charged cosmic rays, gamma-rays, to space weather, while focusing on the energy spectra of electrons and protons.

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  • CALET Results after Three Years on Orbit on the International Space Station

    P. Maestro, O. Adriani, Y. Akaike, Y. Asaoka, E. Berti, G. Bigongiari, M. Bongi, P. Brogi, A. Bruno, N. Cannady, C. Checchia, M. L. Cherry, G. Collazuol, T. G. Guzik, M. Ichimura, M. H. Israel, K. Kasahara, Y. Kawakubo, J. F. Krizmanic, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, M. Mori, N. Mori, H. M. Motz, K. Munakata, L. Pacini, F. Palma, P. Papini, B. F. Rauch, S. B. Ricciarini, T. Sakamoto, M. Sasaki, F. Stolzi, A. Sulaj, T. Tamura, S. Torii, J. P. Wefel, K. Yoshida

    Physics of Atomic Nuclei   82 ( 6 ) 766 - 772  2019年11月

    DOI

  • Direct Measurement of the Cosmic-Ray Proton Spectrum from 50 GeV to 10 TeV with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, J. E. Suh, A. Sulaj, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Physical Review Letters   122 ( 18 )  2019年05月  [査読有り]

     概要を見る

    © 2019 authors. In this paper, we present the analysis and results of a direct measurement of the cosmic-ray proton spectrum with the CALET instrument onboard the International Space Station, including the detailed assessment of systematic uncertainties. The observation period used in this analysis is from October 13, 2015 to August 31, 2018 (1054 days). We have achieved the very wide energy range necessary to carry out measurements of the spectrum from 50 GeV to 10 TeV covering, for the first time in space, with a single instrument the whole energy interval previously investigated in most cases in separate subranges by magnetic spectrometers (BESS-TeV, PAMELA, and AMS-02) and calorimetric instruments (ATIC, CREAM, and NUCLEON). The observed spectrum is consistent with AMS-02 but extends to nearly an order of magnitude higher energy, showing a very smooth transition of the power-law spectral index from-2.81±0.03 (50-500 GeV) neglecting solar modulation effects (or-2.87±0.06 including solar modulation effects in the lower energy region) to-2.56±0.04 (1-10 TeV), thereby confirming the existence of spectral hardening and providing evidence of a deviation from a single power law by more than 3σ.

    DOI PubMed

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  • Measurements of Heavy Cosmic-Ray Nuclei Spectra with CALET on the ISS

    Yosui Akaike

    26TH EXTENDED EUROPEAN COSMIC RAY SYMPOSIUM   1181  2019年

     概要を見る

    CALorimetric Electron Telescope (CALET) has been accumulating data of high-energy cosmic rays on the International Space Station since August 2015. In addition to the primary observation of the all-electron spectra, CALET also measures the spectra of nuclei, their relative abundances and secondary-to-primary ratios to the highest energy region ever directly observed in order to investigate details of their origin and propagation in the galaxy. The CALET instrument consists of two layers of segmented plastic scintillators to identify the individual elements from Z = 1 to 40, a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter to obtain complementary charge and tracking information, and a 27 radiation length thick segmented PWO calorimeter to measure the energy. In this paper, the capability of CALET to perform nuclei measurements and preliminary energy spectra of heavy nuclei components using 962 days of data is presented.

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  • Solar modulation of galactic cosmic-ray electrons measured with CALET

    Shoko Miyake, Yotaro Migita, Yoichi Asaoka, Yosui Akaike, Shoji Torii, Toshio Terasawa, Ryuho Kataoka, Kenichi Sakai

    Proceedings of Science   358  2019年

     概要を見る

    The CALorimetric Electron Telescope (CALET) installed on the International Space Station has multiple event trigger modes for measuring high-energy particles and gamma rays. The observations of the low-energy cosmic-ray (CR) electrons (electrons + positrons) in an energy region from 1 GeV to 10 GeV have been successfully performed by a low-energy shower trigger mode working in the geomagnetic polar regions. The continuous measurements of the low-energy CR electrons may provide a crucial key to the understanding of the solar modulation of the galactic cosmic rays. Here we have analyzed the low-energy CR electrons measured by CALET over the past three years to investigate the solar modulation of the CR electrons. We have obtained the continuous variation of the low-energy electron flux increasing as time passes, which have been expected from a recent weakening solar cycle. We have also confirmed that there are additional small fluctuations in the flux, that has a potential to be explained by the effects of the interplanetary coronal mass ejections or the co-rotating interaction region of the solar wind.

  • Characteristics and Performance of the CALorimetric Electron Telescope (CALET) Calorimeter for Gamma-Ray Observations

    N. Cannady, Y. Asaoka, F. Satoh, M. Tanaka, S. Torii, M. L. Cherry, M. Mori, O. Adriani, Y. Akaike, K. Asano, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, G. Castellini, C. Checchia, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, K. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A.De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, J. E. Suh, A. Sulaj, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Astrophysical Journal, Supplement Series   238 ( 1 )  2018年09月

     概要を見る

    The CALorimetric Electron Telescope primary detector (CALET-CAL) is a 30 radiation-length-deep hybrid calorimeter designed for the accurate measurement of high-energy cosmic rays. It is capable of triggering on and giving near complete containment of electromagnetic showers from primary electrons and gamma rays from 1 GeV to over 10 TeV. The first 24 months of on-orbit scientific data (2015 November 01-2017 October 31) provide valuable characterization of the performance of the calorimeter based on analyses of the gamma-ray data set in general and bright point sources in particular. We describe the gamma-ray analysis, the expected performance of the calorimeter based on Monte Carlo simulations, the agreement of the flight data with the simulated results, and the outlook for long-term gamma-ray observations with the CAL.

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  • Search for GeV Gamma-Ray Counterparts of Gravitational Wave Events by CALET

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, H. S. Krawczynski, J. F. Krizmanic, K. Kohri, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, J. E. Suh, A. Sulaj, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Astrophysical Journal   863 ( 2 )  2018年08月  [査読有り]

     概要を見る

    © 2018. The American Astronomical Society. All rights reserved. We present the results of searches for gamma-ray counterparts of the LIGO/Virgo gravitational wave events using CALorimetric Electron Telescope (CALET) observations. The main instrument of CALET, CALorimeter (CAL), observes gamma-rays from ∼1 GeV up to 10 TeV with a field of view (FOV) of nearly 2 sr. In addition, the CALET gamma-ray burst monitor views ∼3 sr and ∼2π sr of the sky in the 7 keV-1 MeV and the 40 keV-20 MeV bands, respectively, by using two different crystal scintillators. The CALET observations on the International Space Station started in 2015 October, and here we report analyses of events associated with the following gravitational wave events: GW151226, GW170104, GW170608, GW170814, and GW170817. Although only upper limits on gamma-ray emission are obtained, they correspond to a luminosity of 1049 ∼ 1053 erg s-1 in the GeV energy band depending on the distance and the assumed time duration of each event, which is approximately on the order of luminosity of typical short gamma-ray bursts. This implies that there will be a favorable opportunity to detect high-energy gamma-ray emission in further observations if additional gravitational wave events with favorable geometry will occur within our FOV. We also show the sensitivity of CALET for gamma-ray transient events, which is on the order of 10-7 erg cm-2 s-1 for an observation of 100 s in duration.

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  • On-orbit operations and offline data processing of CALET onboard the ISS

    Y. Asaoka, S. Ozawa, S. Torii, O. Adriani, Y. Akaike, K. Asano, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, A. Javaid, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, H. S. Krawczynski, J. F. Krizmanic, S. Kuramata, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. de Nolfo, S. Okuno, J. F. Ormes, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Astroparticle Physics   100   29 - 37  2018年07月  [査読有り]

     概要を見る

    © 2018 Elsevier B.V. The CALorimetric Electron Telescope (CALET), launched for installation on the International Space Station (ISS) in August, 2015, has been accumulating scientific data since October, 2015. CALET is intended to perform long-duration observations of high-energy cosmic rays onboard the ISS. CALET directly measures the cosmic-ray electron spectrum in the energy range of 1 GeV to 20 TeV with a 2% energy resolution above 30 GeV. In addition, the instrument can measure the spectrum of gamma rays well into the TeV range, and the spectra of protons and nuclei up to a PeV. In order to operate the CALET onboard ISS, JAXA Ground Support Equipment (JAXA-GSE) and the Waseda CALET Operations Center (WCOC) have been established at JAXA and Waseda University, respectively. Scientific operations using CALET are planned at WCOC, taking into account orbital variations of geomagnetic rigidity cutoff. Scheduled command sequences are used to control the CALET observation modes on orbit. Calibration data acquisition by, for example, recording pedestal and penetrating particle events, a low-energy electron trigger mode operating at high geomagnetic latitude, a low-energy gamma-ray trigger mode operating at low geomagnetic latitude, and an ultra heavy trigger mode, are scheduled around the ISS orbit while maintaining maximum exposure to high-energy electrons and other high-energy shower events by always having the high-energy trigger mode active. The WCOC also prepares and distributes CALET flight data to collaborators in Italy and the United States. As of August 31, 2017, the total observation time is 689 days with a live time fraction of the total time of ∼ 84%. Nearly 450 million events are collected with a high-energy (E > 10 GeV) trigger. In addition, calibration data acquisition and low-energy trigger modes, as well as an ultra-heavy trigger mode, are consistently scheduled around the ISS orbit. By combining all operation modes with the excellent-quality on-orbit data collected thus far, it is expected that a five-year observation period will provide a wealth of new and interesting results.

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  • Extended Measurement of the Cosmic-Ray Electron and Positron Spectrum from 11 GeV to 4.8 TeV with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, J. E. Suh, A. Sulaj, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Physical Review Letters   120 ( 26 )  2018年06月  [査読有り]

     概要を見る

    © 2018 American Physical Society. Extended results on the cosmic-ray electron + positron spectrum from 11 GeV to 4.8 TeV are presented based on observations with the Calorimetric Electron Telescope (CALET) on the International Space Station utilizing the data up to November 2017. The analysis uses the full detector acceptance at high energies, approximately doubling the statistics compared to the previous result. CALET is an all-calorimetric instrument with a total thickness of 30 X0 at normal incidence and fine imaging capability, designed to achieve large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum in the region below 1 TeV shows good agreement with Alpha Magnetic Spectrometer (AMS-02) data. In the energy region below ∼300 GeV, CALET's spectral index is found to be consistent with the AMS-02, Fermi Large Area Telescope (Fermi-LAT), and Dark Matter Particle Explorer (DAMPE), while from 300 to 600 GeV the spectrum is significantly softer than the spectra from the latter two experiments. The absolute flux of CALET is consistent with other experiments at around a few tens of GeV. However, it is lower than those of DAMPE and Fermi-LAT with the difference increasing up to several hundred GeV. The observed energy spectrum above ∼1 TeV suggests a flux suppression consistent within the errors with the results of DAMPE, while CALET does not observe any significant evidence for a narrow spectral feature in the energy region around 1.4 TeV. Our measured all-electron flux, including statistical errors and a detailed breakdown of the systematic errors, is tabulated in the Supplemental Material in order to allow more refined spectral analyses based on our data.

    DOI PubMed

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  • Energy Spectrum of Cosmic-Ray Electron and Positron from 10 GeV to 3 TeV Observed with the Calorimetric Electron Telescope on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, A. Javaid, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, H. S. Krawczynski, J. F. Krizmanic, S. Kuramata, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Physical Review Letters   119 ( 18 )  2017年11月  [査読有り]

     概要を見る

    © 2017 Published by the American Physical Society. First results of a cosmic-ray electron and positron spectrum from 10 GeV to 3 TeV is presented based upon observations with the CALET instrument on the International Space Station starting in October, 2015. Nearly a half million electron and positron events are included in the analysis. CALET is an all-calorimetric instrument with total vertical thickness of 30 X0 and a fine imaging capability designed to achieve a large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum over 30 GeV can be fit with a single power law with a spectral index of -3.152±0.016 (stat+syst). Possible structure observed above 100 GeV requires further investigation with increased statistics and refined data analysis.

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  • Relativistic electron precipitation at International Space Station: Space weather monitoring by Calorimetric Electron Telescope

    Ryuho Kataoka, Yoichi Asaoka, Shoji Torii, Toshio Terasawa, Shunsuke Ozawa, Tadahisa Tamura, Yuki Shimizu, Yosui Akaike, Masaki Mori

    GEOPHYSICAL RESEARCH LETTERS   43 ( 9 ) 4119 - 4125  2016年05月  [査読有り]

     概要を見る

    The charge detector (CHD) of the Calorimetric Electron Telescope (CALET) on board the International Space Station (ISS) has a huge geometric factor for detecting MeV electrons and is sensitive to relativistic electron precipitation (REP) events. During the first 4 months, CALET CHD observed REP events mainly at the dusk to midnight sector near the plasmapause, where the trapped radiation belt electrons can be efficiently scattered by electromagnetic ion cyclotron (EMIC) waves. Here we show that interesting 5-20 s periodicity regularly exists during the REP events at ISS, which is useful to diagnose the wave-particle interactions associated with the nonlinear wave growth of EMIC-triggered emissions.

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    21
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  • 19aAZ-4 軌道上データを用いたCALET検出器のMIP較正

    小宮 優馬, 鳥居 祥二, 笠原 克晶, 赤池 陽水, 浅岡 陽一, 小澤 俊介, Motz Holger, 清水 雄輝, 田村 忠久, CALETチーム

    日本物理学会講演概要集   71   459 - 459  2016年

    DOI CiNii

  • 19aAZ-7 CALET観測における宇宙線到来方向の決定方法

    佐藤 郁也, 鳥居 祥二, 浅岡 陽一, 笠原 克昌, 赤池 陽水, 小澤 俊介, 竹本 翔一, 中平 聡, CALET チーム

    日本物理学会講演概要集   71   461 - 461  2016年

    DOI CiNii

  • The CALorimetric Electron Telescope (CALET) for high-energy astroparticle physics on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, J. H. Buckley, G. Castellini, M. L. Cherry, G. Collazuol, K. Ebisawa, V. Di Felice, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, M. H. Israel, A. Javaid, E. Kamioka, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, N. Kawanaka, H. Kitamura, T. Kotani, H. S. Krawczynski, J. F. Krizmanic, A. Kubota, S. Kuramata, T. Lomtadze, P. Maestro, L. Marcelli, P. S. Marrocchesi, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, Y. E. Nakagawa, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, F. Palma, P. Papini, B. F. Rauch, S. B. Ricciarini, T. Sakamoto, M. Sasaki, M. Shibata, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Journal of Physics: Conference Series   632 ( 1 )  2015年08月

     概要を見る

    The CALorimetric Electron Telescope (CALET) is a space experiment, currently under development by Japan in collaboration with Italy and the United States, which will measure the flux of cosmic-ray electrons (and positrons) up to 20 TeV energy, of gamma rays up to 10 TeV, of nuclei with Z from 1 to 40 up to 1 PeV energy, and will detect gamma-ray bursts in the 7 keV to 20 MeV energy range during a 5 year mission. These measurements are essential to investigate possible nearby astrophysical sources of high energy electrons, study the details of galactic particle propagation and search for dark matter signatures. The main detector of CALET, the Calorimeter, consists of a module to identify the particle charge, followed by a thin imaging calorimeter (3 radiation lengths) with tungsten plates interleaving scintillating fibre planes, and a thick energy measuring calorimeter (27 radiation lengths) composed of lead tungstate logs. The Calorimeter has the depth, imaging capabilities and energy resolution necessary for excellent separation between hadrons, electrons and gamma rays. The instrument is currently being prepared for launch (expected in 2015) to the International Space Station ISS, for installation on the Japanese Experiment Module - Exposure Facility (JEM-EF).

    DOI

    Scopus

    6
    被引用数
    (Scopus)
  • Energy calibration of Calorimetric Electron Telescope (CALET) in space

    Tae Niita, Shoji Torii, Yosui Akaike, Yoichi Asaoka, Katsuaki Kasahara, Shunsuke Ozawa, Tadahisa Tamura

    ADVANCES IN SPACE RESEARCH   55 ( 11 ) 2500 - 2508  2015年06月  [査読有り]

     概要を見る

    The Calorimetric Electron Telescope (CALET) is a space experiment, currently under development by Japan in collaboration with Italy and the United States. CALET will measure the flux of cosmic ray electrons (including positrons) up to 20 TeV, gamma-rays up to 10 TeV and nuclei from Z = 1 up to 40 up to 1000 TeV during a two-year mission on the International Space Station (ISS), extendable to five years. The unique feature of CALET is its thick, fully active calorimeter that allows measurements well into the TeV energy region with excellent energy resolution (&lt; 3%), coupled with a fine imaging upper calorimeter to accurately identify the starting point of electromagnetic showers. For continuous high performance of the detector, it is required to calibrate each detector component on orbit. We use the measured response to minimum ionizing particles for the energy calibration, taking data in a dedicated trigger mode and selecting useful events in off-line analysis. In this paper, we present on-orbit and off-line data handling methods for the energy calibration developed through beam tests at CERN-SPS and Monte Carlo simulations. (C) 2015 COSPAR. Published by Elsevier Ltd. All rights reserved.

    DOI

    Scopus

    20
    被引用数
    (Scopus)
  • The CALorimetric Electron Telescope (CALET) for high-energy astroparticle physics on the International Space Station

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, J. H. Buckley, G. Castellini, M. L. Cherry, G. Collazuol, K. Ebisawa, V. Di Felice, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, M. H. Israel, A. Javaid, E. Kamioka, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, N. Kawanaka, H. Kitamura, T. Kotani, H. S. Krawczynski, J. F. Krizmanic, A. Kubota, S. Kuramata, T. Lomtadze, P. Maestro, L. Marcelli, P. S. Marrocchesi, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, Y. E. Nakagawa, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, F. Palma, P. Papini, B. F. Rauch, S. B. Ricciarini, T. Sakamoto, M. Sasaki, M. Shibata, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    EPJ Web of Conferences   95  2015年05月

     概要を見る

    The CALorimetric Electron Telescope (CALET) is a space experiment, currently under development by Japan in collaboration with Italy and the United States, which will measure the flux of cosmic-ray electrons (and positrons) up to 20 TeV energy, of gamma rays up to 10 TeV, of nuclei with Z from 1 to 40 up to 1 PeV energy, and will detect gamma-ray bursts in the 7 keV to 20 MeV energy range during a 5 year mission. These measurements are essential to investigate possible nearby astrophysical sources of high energy electrons, study the details of galactic particle propagation and search for dark matter signatures. The main detector of CALET, the Calorimeter, consists of a module to identify the particle charge, followed by a thin imaging calorimeter (3 radiation lengths) with tungsten plates interleaving scintillating fibre planes, and a thick energy measuring calorimeter (27 radiation lengths) composed of lead tungstate logs. The Calorimeter has the depth, imaging capabilities and energy resolution necessary for excellent separation between hadrons, electrons and gamma rays. The instrument is currently being prepared for launch (expected in 2015) to the International Space Station ISS, for installation on the Japanese Experiment Module - Exposure Facility (JEM-EF).

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • 26pSJ-2 Waseda CALET Operations Center (WCOC)におけるミッション運用

    浅岡 陽一, 鳥居 祥二, 赤池 陽水, 小澤 俊介, 笠原 克昌, 神尾 泰樹, 竹本 翔一, 仁井田 多絵, 山口 優幸, 大和 啓一, Motz Holger, 清水 雄輝, 田村 忠久, 上野 史郎, 冨田 洋, CALETチーム

    日本物理学会講演概要集   70   365 - 365  2015年

    DOI CiNii

  • 21pDC-9 Expected Dark Matter Sensitivity of CALET in Relation to Present and Future AMS-02 Observation

    Motz Holger, Asaoka Yoichi, Torii Shoji, Bhattacharyya Saptashwa, Niita Tae, Okada Yuko, Akaike Yosui, CALET collaboration

    日本物理学会講演概要集   70   402 - 402  2015年

    DOI CiNii

  • 21pDC-8 CALETにおける原子核成分スペクトル観測性能

    佐藤 文佳, 鳥居 祥二, 斎藤 優, 仁井田 多絵, 浅岡 陽一, 笠原 克昌, 小澤 俊介, 赤池 陽水, CALETチーム

    日本物理学会講演概要集   70   401 - 401  2015年

    DOI CiNii

  • A balloon experiment using CALET prototype (bCALET-2)

    Tae Niita, Shoji Torii, Katsuaki Kasahara, Hiroyuki Murakami, Shunsuke Ozawa, Yoshitaka Ueyama, Yosui Akaike, Tadahisa Tamura, Kenji Yoshida, Yusaku Katayose, Yuki Shimizu, Hideyuki Fuke

    ADVANCES IN SPACE RESEARCH   55 ( 2 ) 753 - 760  2015年01月  [査読有り]

     概要を見る

    CALET (CALorimetric Electron Telescope) is a high energy cosmic-ray detector to be installed on International Space Station in 2015 to carry out accurate measurements of high energy electrons and gamma-rays. For verification of the detector performance, we carried out balloon experiments using CALET prototype detectors in May 2006 (bCALET-1) and in August 2009 (bCALET-2). In this paper we mainly report about the second experiment using bCALET-2. bCALET-2 is a calorimetric instrument composed of a 3.58 radiation length thick tungsten-scintillating fiber imaging calorimeter (IMC) and a 13.4 radiation length thick bismuth germanium-oxide calorimeter (TASC). The concept of the structure is similar to that of CALET, but the number of sensors and the thickness of materials were optimized for the balloon experiment. The observation was carried out at the Taiki Aerospace Research Field of JAXA in Hokkaido, and the detector was flown successfully for 2.5 h at a level altitude of 35 km. The observed events were analyzed by methods developed through Monte Carlo simulations, and the energy spectra of electrons and atmospheric gamma-rays in the energy range of 1-30 GeV were obtained and compared to the results of previous experiments. (C) 2014 COSPAR. Published by Elsevier Ltd. All rights reserved.

    DOI J-GLOBAL

    Scopus

    3
    被引用数
    (Scopus)
  • The CALET structure and thermal model used for beam test at CERN

    Ueyama Yoshitaka, Torii Shoji, Kasahara Katsuaki, Ozawa Shunsuke, Niita Tae, Nakamura Masanori, Kaneko Shogo, Katahira Ryo, Murata Akira, Tamura Tadahisa, Katayose Yusaku, Akaike Yosui, Shimizu Yuki

    Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013   2013-October  2013年

     概要を見る

    The Calorimetric Electron Telescope (CALET) is a new space experiment for astroparticle physics, which will carry out a five-year observation at the Japanese Experiment Module-Exposed Facility (JEM-EF) of the International Space Station (ISS). The experiment, currently under development by Japan in collaboration with Italy and the United States, will measure mainly the flux of cosmic-ray electrons (including positrons) to 20 TeV, gamma-rays to 10 TeV, and nuclei with Z=1 to 40 up to 1000 TeV. We have carried out a beam test of the CALET calorimeter at CERN-SPS by using the Beam-Test Model (BTM), which consisted of the Structure and Thermal Model (STM) and the Bread Board Model(BBM) of the front end circuits. The model consists of the same support structure as the CALET flight model and it includes the Imaging Calorimeter (IMC), the Total Absorption Calorimeter(TASC) and the Charge Detector(CHD). A part of the sensors; the scintillating fibers in the IMC, the PWO logs in the TASC, and the plastic scintillators paddles in the CHD, was adapted for the test. We will describe the model, and will report the basic performance obtained in the beam test.

  • Beam test performance of a scintillator-based detector for the charge identification of relativistic ions

    P. S. Marrocchesi, O. Adriani, Y. Akaike, M. G. Bagliesi, A. Basti, G. Bigongiari, S. Bonechi, M. Bongi, M. Y. Kim, T. Lomtadze, P. Maestro, T. Niita, S. Ozawa, Y. Shimizu, S. Torii

    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   659 ( 1 ) 477 - 483  2011年12月  [査読有り]

     概要を見る

    We report on the measurements performed with relativistic ions from Be to Fe, at the Fragment Separator (FRS) of the GSI Helmholtzzentrum fur Schwerionenforschung in Darmstadt, to test the performance of charge-sensitive detectors that were designed to separate - via multiple dE/dx measurements - fully stripped nuclei of cosmic origin in the experiment CALET. The latter is a space mission by the Japanese Space Agency (JAXA) scheduled to be launched to the International Space Station (ISS) in 2013. The CALET instrument is managed by an international collaboration and it is scheduled to take data for 5 years on the Exposure Facility (JEM-EF) of the Japanese module KIBO on the ISS.
    The aim of the test was to accurately measure the response of the scintillator to different nuclear species and parametrize the saturation of the scintillation light in order to assess the impact of this effect on the charge resolution of the instrument. (C) 2011 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    61
    被引用数
    (Scopus)
  • Performance of the CALET prototype: CERN beam test

    Mikihiko Karube, Shoji Torii, Katsuaki Kasahara, Shunsuke Ozawa, Yosui Akaike, Toshihide Aiba, Yoshitaka Ueyama, Masanori Nakamura, Keisuke Yoshida, Tadahisa Tamura, Shoji Okuno, Yusaku Katayose, Yuki Shimizu

    Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011   6   383 - 386  2011年

     概要を見る

    We are developing the CALET mission to observe high energy cosmic rays at the Japanese Experiment Module/Exposed Facility (JEM/EF) on the International Space Station. The instrument will be flown in 2013, and will be used for 5 years. The primary scientific purpose of CALET is to search for nearby cosmic ray sources and dark matter. We carried out an accelerator beam test with high energy particles with the CALET prototype at the CERN-SPS. The purpose of this test was to assess the detector performance as well as to study the accuracy of the Monte Carlo simulation method. The prototype detector consists of an imaging calorimeter with 256 scintillating fibers and a total absorption calorimeter consisting of 16 PWO logs. The longitudinal structure is similar with the CALET instrument. We used positron and proton beams in the energy region from 6 to 200 GeV, and from 30 to 150 GeV, respectively. Comparing the experimental data with the simulation results, we have measured the energy deposition in each component, the energy resolution, the lateral shower spread and the e/p separation capability.

    DOI

    Scopus

    2
    被引用数
    (Scopus)
  • The CALET CHD for determination of nuclear charge

    Yuki Shimizu, Oscar Adriani, Yosui Akaike, Carlo Avanzini, Maria Grazia Bagliesi, Andrea Basti, Gabriele Bigongiari, Massimo Bongi, Guido Castellini, Daijiro Ito, Mikihiko Karube, Katsuaki Kasahara, Me Young Kim, Keinosuke Kondo, Temuriaz Lomtadze, Masanori Nakamura, Paolo Maestro, Pier Simone Marrocchesi, Fabio Morsani, Tae Niita, Sergio Bruno Ricciarini, Shoji Torii, Yoshitaka Ueyama

    Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011   6   391 - 394  2011年  [査読有り]

     概要を見る

    Calorimetric Electron Telescope (CALET) will be a high energy cosmic ray observatory on the Japanese Experimental Module - Exposed Facility of the International Space Station. In addition to electrons and gamma-rays, CALET has an excellent detection capability of cosmic ray nuclei. In order to determine the atomic number of measured nuclei, the CHarge Detector (CHD) is placed on the top of the calorimeter. The CALET-CHD consists of two orthogonal layers of plastic scintillator charge-measuring modules. Each layer is segmented into 14 scintillator paddles (45 cm×3.2 cm×1 cm) for the reduction of back scattering effects. We evaluated the charge resolution of the plastic scintillators with heavy ion accelerators. In this presentation, we will report the design of the CALET-CHD and its nuclei identification capability as inferred from heavy ion beam tests.

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • The event trigger system for CALET

    Yoshitaka Ueyama, Shoji Torii, Katsuaki Kasahara, Hiroyuki Murakami, Shunsuke Ozawa, Yosui Akaike, Tae Niita, Masanori Nakamura, Keisuke Yoshida, Tadahisa Tamura, Shoji Okuno, Yusaku Katayose, Yuki Shimizu

    Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011   6   387 - 390  2011年  [査読有り]

     概要を見る

    The CALorimetric Electron Telescope, CALET, is a mission to study high energy phenomena in the universe by observing high energy cosmic rays (electrons, gamma rays, and nuclei) on the International Space Station. The instrument consists of a segmented plastic scintillator charge-measuring module, an imaging calorimeter consisting of 8 scintillating fiber planes interleaved with tungsten plates of 3 radiation length, and a total absorption calorimeter consisting of orthogonal PWO logs of 27 radiation length. It is necessary to eliminate the background events, mostly low energy protons that prevent efficient observation of high energy cosmic rays. Therefore, CALET has an on-board trigger system to select events which are 1) high energy showers, 2) low energy showers and 3) non-interacting protons or heavy nuclei. These triggers are generated by a combination of the signals from the charge detector, the imaging calorimeter, and the top layer of PWO in the total absorption calorimeter. A CERN-SPS beam test of the CALET prototype detector was carried out by using muons, electrons, and hadrons. We introduce the CALET trigger system and present its performance verified during the beam test.

    DOI

    Scopus

  • Measurements of cosmic-ray electron and gamma-ray flux with balloon-borne CALET prototype

    T. Niita, S. Torii, K. Kasahara, T. Tamura, K. Yoshida, Y. Katayose, H. Murakami, S. Ozawa, Y. Shimizu, Y. Akaike, Y. Ueyama, D. Ito, M. Karube, K. Kondo, M. Kyutan

    Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011   6   21 - 24  2011年  [査読有り]

     概要を見る

    We carried out the balloon experiments using CALET (CALorimetric Electron Telescope) prototype detectors in May 2006 (bCALET-1) and August 2009 (bCALET-2) for verification of both the detector performance and the capability of measuring the cosmic rays at higher atmosphere. The bCALET-2 instrument for observing the electrons and the gamma rays at energies in 1-100 GeV is composed of an imaging calorimeter consisting of 4096 scintillating fibers with a total of 3.6 radiation lengths of tungsten plates, and a total absorption calorimeter consisting of crossed 60 BGO logs with a total of 13.4 radiation lengths depth. The bCALET-2 was launched from the Taiki Aerospace Research Field, Japan Aerospace Exploration Agency, in Hokkaido, and flew successfully for 2.5 hours at a level altitude of 35 km. In this paper, we will present the spectra of electrons and gamma rays in the energy range of 1-100 GeV measured by bCALET-2, comparing with our previous observations, bCALET-1 and BETS. The detector performance is studied by comparing with the simulations, and the observed fluxes are found to be compatible with the expected.

    DOI

    Scopus

    2
    被引用数
    (Scopus)
  • Expected CALET telescope performance from monte carlo simulations

    Yosui Akaike, Katsuaki Kasahara, Shoji Torii, Shunsuke Ozawa, Yuki Shimizu, Mikihiko Karube, Keisuke Yoshida, Kenji Yoshida, Masakatsu Ichimura

    Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011   6   371 - 374  2011年  [査読有り]

     概要を見る

    The CALorimetric Electron Telescope, CALET, is a versatile detector for exploring the high energy universe, planned to be placed on the Japanese Experiment Module Facility of the International Space Station, ISS. CALET is designed to perform direct measurements of electrons from 1 GeV to 20 TeV, gamma-rays from 10 GeV to 10 TeV, and protons and nuclei from several 10 GeV to 1000 TeV. The main detector consists of a Charge Detector (CHD), an Imaging Calorimeter (IMC), and a Total Absorption Calorimeter (TASC). The total thickness of the calorimeter is 30 X0 for electromagnetic particles or 1.3 λ for protons. We have been carrying out Monte Carlo simulations with EPICS to study the CALET performance. With its imaging and deep calorimeter, CALET provides excellent proton rejection, ∼ 105, and a high energy resolution, ∼2%, over 100 GeV for electromagnetic particles, which make possible the observation of electrons and gamma-rays into the TeV region. In this paper, we will present the expected performance in observing the different particle species, including the geometric factor, the trigger efficiency, the energy resolution and the particle identification power.

    DOI

    Scopus

    14
    被引用数
    (Scopus)
  • The balloon-bone CALET prototype detector (bCALET)

    Shunsuke Ozawa, Shoji Torii, Katsuaki Kasahara, Hiroyuki Murakami, Yosui Akaike, Yoshitaka Ueyama, Daijiro Ito, Motohiko Karube, Keinosuke Kondo, Tae Niita, Tadahisa Tamura, Yusaku Katayose, Kenji Yoshida, Yoshitaka Saito, Hideyuki Fuke, Jiro Kawada

    Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011   6   71 - 74  2011年  [査読有り]

     概要を見る

    The CALET payload will be installed in the Japanese Experiment Module Exposed Facility (JEM-EF) of the International Space Station (ISS). We developed a balloon-borne payload to evaluate the performance of CALET by carrying out precursor flights for the electron and gamma-ray observations. The first flight of bCALET-1 (balloon-borne CALET prototype) was carried out in 2006, and the enhanced version, bCALET-2, was successfully flown in August 2009. The bCALET-2 is composed of IMaging Calorimeter (IMC) and Total AbSorption Calorimeter (TASC). The IMC has an area of 256 mm × 256 mm, and is consisted of 8 layers of scintillating fiber belts with a total 3.6 radiation lengths of tungsten plates interleaved within the fiber planes for imaging the pre-shower development. TASC is consisted of crossed BGO logs (25 mm × 25 mm × 300 mm in each) with a total of 13.4 radiation lengths depth, for measuring the total energy deposit of incoming shower particles. The geometry factor is nearly 320 cm2sr over 10 GeV. We succeeded the observation of the electron energy spectrum in 1 GeV ∼ several 10 GeV electron and the atmospheric gamma-rays in 1 GeV ∼ a few 10 GeV, which are consistent with previous observations by BETS. The results are compared with simulations for confirming the detector performance.

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Simulated performance of the calorimetric electron telescope (CALET) experiment(共著)

    AKAIKE Y, TAIRA K, KASAHARA K, TORII S, SHIMIZU Y, YOSHIDA K

    Adv. Space Res.   45 ( 5 ) 690 - 697  2010年03月  [査読有り]

    DOI

    Scopus

    8
    被引用数
    (Scopus)
  • Expected Performance of CALET by Monte Carlo Simulation(共著)

    Akaike, Y, Kasahara, K, Torii, S, Shimizij, Y, Taira, K, Yoshida, K, Watanabe, I

    J. Phys. Soc. Jpn. Suppl. A   78   169 - 172  2009年  [査読有り]

    DOI

    Scopus

    1
    被引用数
    (Scopus)
  • Balloon borne experiment with CALET prototype

    Y. Shimizu, S. Torii, K. Kasahara, Y. Akaike, Y. Fukuta, K. Hidaka, K. Taira, T. Tamura, K. Yoshida, Y. Katayose, H. Murakami

    Journal of the Physical Society of Japan   78 ( Suppl.A ) 165 - 168  2009年  [査読有り]

     概要を見る

    We carried out a balloon observation of cosmic rays with a prototype of the CALET (bCALET-1) at the Sanriku Balloon Center of the Japan Aerospace Exploration Agency. The main purpose of the experiment was verification of the CALET. The detector consists of 1024 scintillating fibers for precise imaging and 24 BGO scintillator for total absorption of showers. The observation was carried at an altitude between 35 and 37 km for about 3.5 hours. We measured electrons in the energy region between 1 to 10 GeV. The prototype system was verified in the balloon environment. We have obtained the electron flux which is useful to investigate solar modulation. In combination with the flux between 10 to 100GeV measured by BETS, rigidity cutoff effect was clearly observed. These results showed good agreement with that of our Monte-Carlo simulation and demonstrated the detection capability of the CALET in the enegy region below 10 GeV. Now we are planning a series of balloon experiments with larger-scale detectors and longer-duration flights, which include one-month observation by a super-pressure balloon. © 2009 The Physical Society of Japan.

    DOI

    Scopus

    4
    被引用数
    (Scopus)

▼全件表示

Misc

  • CALETの電子・陽子解析による太陽変調の観測

    高柚季乃, 加藤千尋, 宗像一起, 浅岡陽一, 鳥居祥二, 赤池陽水, 小林兼好, 片岡龍峰, 三宅晶子, 中平聡志, 笠原克昌

    日本物理学会講演概要集(CD-ROM)   75 ( 2 )  2020年

    J-GLOBAL

  • The CALorimetric Electron Telescope (CALET) on the international space station: Results from the first two years on orbit

    Y. Asaoka, O. Adriani, Y. Akaike, K. Asano, M. G. Bagliesi, E. Berti, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, A. Bruno, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, S. Nakahira, J. Nishimura, G. A. De Nolfo, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, V. Pal'Shin, P. Papini, A. V. Penacchioni, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, S. Sugita, J. E. Suh, A. Sulaj, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida

    Journal of Physics: Conference Series   1181 ( 1 )  2019年03月  [査読有り]

     概要を見る

    © Published under licence by IOP Publishing Ltd. The CALorimetric Electron Telescope (CALET) is a high-energy astroparticle physics space experiment installed on the International Space Station (ISS), developed and operated by Japan in collaboration with Italy and the United States. The CALET mission goals include the investigation of possible nearby sources of high-energy electrons, of the details of galactic particle acceleration and propagation, and of potential signatures of dark matter. CALET measures the cosmic-ray electron+positron flux up to 20 TeV, gamma-rays up to 10 TeV, and nuclei with Z=1 to 40 up to 1, 000 TeV for the more abundant elements during a long-term observation aboard the ISS. Starting science operation in mid-October 2015, CALET performed continuous observation without major interruption with close to 20 million triggered events over 10 GeV per month. Based on the data taken during the first two-years, we present an overview of CALET observations: 1) Electron+positron energy spectrum, 2) Nuclei analysis, 3) Gamma-ray observation including a characterization of on-orbit performance. Results of the electromagnetic counterpart search for LIGO/Virgo gravitational wave events are discussed as well.

    DOI

  • Energy calibration of CALET onboard the International Space Station

    Y. Asaoka, Y. Akaike, Y. Komiya, R. Miyata, S. Torii, O. Adriani, K. Asano, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, A. Javaid, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, H. Kitamura, H. S. Krawczynski, J. F. Krizmanic, S. Kuramata, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, Y. E. Nakagawa, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Astroparticle Physics   91   1 - 10  2017年05月

     概要を見る

    © 2017 The Authors In August 2015, the CALorimetric Electron Telescope (CALET), designed for long exposure observations of high energy cosmic rays, docked with the International Space Station (ISS) and shortly thereafter began to collect data. CALET will measure the cosmic ray electron spectrum over the energy range of 1 GeV to 20 TeV with a very high resolution of 2% above 100 GeV, based on a dedicated instrument incorporating an exceptionally thick 30 radiation-length calorimeter with both total absorption and imaging (TASC and IMC) units. Each TASC readout channel must be carefully calibrated over the extremely wide dynamic range of CALET that spans six orders of magnitude in order to obtain a degree of calibration accuracy matching the resolution of energy measurements. These calibrations consist of calculating the conversion factors between ADC units and energy deposits, ensuring linearity over each gain range, and providing a seamless transition between neighboring gain ranges. This paper describes these calibration methods in detail, along with the resulting data and associated accuracies. The results presented in this paper show that a sufficient accuracy was achieved for the calibrations of each channel in order to obtain a suitable resolution over the entire dynamic range of the electron spectrum measurement.

    DOI

  • CALET UPPER LIMITS on X-RAY and GAMMA-RAY COUNTERPARTS of GW151226

    O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, M. G. Bagliesi, G. Bigongiari, W. R. Binns, S. Bonechi, M. Bongi, P. Brogi, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, V. Di Felice, K. Ebisawa, H. Fuke, T. G. Guzik, T. Hams, M. Hareyama, N. Hasebe, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, A. Javaid, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, H. Kitamura, H. S. Krawczynski, J. F. Krizmanic, S. Kuramata, T. Lomtadze, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J. W. Mitchell, S. Miyake, K. Mizutani, A. A. Moiseev, K. Mori, M. Mori, N. Mori, H. M. Motz, K. Munakata, H. Murakami, Y. E. Nakagawa, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, L. Pacini, F. Palma, P. Papini, A. V. Penacchioni, B. F. Rauch, S. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, F. Stolzi, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tsunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Astrophysical Journal Letters   829 ( 1 )  2016年09月

     概要を見る

    © 2016. The American Astronomical Society. All rights reserved.. We present upper limits in the hard X-ray and gamma-ray bands at the time of the Laser Interferometer Gravitational-wave Observatory (LIGO) gravitational-wave event GW151226 derived from the CALorimetric Electron Telescope (CALET) observation. The main instrument of CALET, CALorimeter (CAL), observes gamma-rays from ∼1 GeV up to 10 TeV with a field of view of ∼2 sr. The CALET gamma-ray burst monitor (CGBM) views ∼3 sr and ∼2π sr of the sky in the 7 keV-1 MeV and the 40 keV-20 MeV bands, respectively, by using two different scintillator-based instruments. The CGBM covered 32.5% and 49.1% of the GW151226 sky localization probability in the 7 keV-1 MeV and 40 keV-20 MeV bands respectively. We place a 90% upper limit of 2 ×10-7 erg cm-2 s-1 in the 1-100 GeV band where CAL reaches 15% of the integrated LIGO probability (∼1.1 sr). The CGBM 7σ upper limits are 1.0 ×10-6 erg cm-2 s-1 (7-500 keV) and 1.8 ×10-6 erg cm-2 s-1 (50-1000 keV) for a 1 s exposure. Those upper limits correspond to the luminosity of 3-5 ×1049 erg s-1, which is significantly lower than typical short GRBs.

    DOI

  • Status and performance of the CALorimetric Electron Telescope (CALET) on the international space station

    O. Adriani, Y. Akaike, Y. Asaoka, K. Asano, M. G. Bagliesi, G. Bigongiari, W. R. Binns, M. Bongi, J. H. Buckley, A. Cassese, G. Castellini, M. L. Cherry, G. Collazuol, K. Ebisawa, V. di Felice, H. Fuke, T. G. Guzik, T. Hamsa, N. Hasebe, M. Hareyama, K. Hibino, M. Ichimura, K. Ioka, M. H. Israel, A. Javaid, E. Kamioka, K. Kasahara, Y. Katayose, J. Kataoka, R. Kataoka, N. Kawanaka, H. Kitamura, T. Kotani, H. S. Krawczynski, J. F. Krizmanic, A. Kubota, S. Kuramata, T. Lomtadze, P. Maestro, L. Marcelli, P. S. Marrocchesi, J. W. Mitchell, S. Miyake, K. Mizutani, H. M. Motz, A. A. Moiseev, K. Mori, M. Mori, N. Mori, K. Munakata, H. Murakami, Y. E. Nakagawa, S. Nakahira, J. Nishimura, S. Okuno, J. F. Ormes, S. Ozawa, F. Palma, P. Papini, B. F. Rauch, S. Ricciarini, T. Sakamoto, M. Sasaki, M. Shibata, Y. Shimizu, A. Shiomi, R. Sparvoli, P. Spillantini, I. Takahashi, M. Takayanagi, M. Takita, T. Tamura, N. Tateyama, T. Terasawa, H. Tomida, S. Torii, Y. Tunesada, Y. Uchihori, S. Ueno, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, T. Yuda

    Nuclear Physics B - Proceedings Supplements   256-257   225 - 232  2014年12月

     概要を見る

    © 2014 Elsevier B.V. The CALorimetric Electron Telescope (CALET) space experiment, currently under development by Japan in collaboration with Italy and the United States, will measure the flux of cosmic-ray electrons (including positrons) to 20 TeV, gamma rays to 10 TeV and nuclei with Z=1 to 40 up to 1,000 TeV during a two-year mission on the International Space Station (ISS), extendable to five years. These measurements are essential to search for dark matter signatures, investigate the mechanism of cosmic-ray acceleration and propagation in the Galaxy and discover possible astrophysical sources of high-energy electrons nearby the Earth. The instrument consists of two layers of segmented plastic scintillators for the cosmic-ray charge identification (CHD), a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter (IMC) and a 27 radiation length thick lead-tungstate calorimeter (TASC). CALET has sufficient depth, imaging capabilities and excellent energy resolution to allow for a clear separation between hadrons and electrons and between charged particles and gamma rays. The instrument will be launched to the ISS within 2014 Japanese Fiscal Year (by the end of March 2015) and installed on the Japanese Experiment Module-Exposed Facility (JEM-EF). In this paper, we will review the status and main science goals of the mission and describe the instrument configuration and performance.

    DOI

  • CALETの運用及びデータ解析・管理システムの概要(宇宙科学情報解析論文誌 第三号)

    赤池 陽水, 浅岡 陽一, 上野 史郎, 田村 忠久, 寺澤 敏夫, 冨田 洋, 鳥居 祥二, 中川 友進, 仁井田 多絵

    宇宙航空研究開発機構研究開発報告   13   99 - 107  2014年03月

     概要を見る

    CALorimetric Electron Telescope (CALET) は国際宇宙ステーションの「きぼう」に搭載予定の宇宙線観測装置で、 2014年から 5年間の観測を実施予定である。CALETの主検出器は、電子( 1 GeV . 20 TeV)、ガンマ線( 10 GeV. 10 TeV)の観測に最適化したカロリメータで、優れたエネルギー分解能と強力な粒子識別能を有し、宇宙線近傍加速源と暗黒物質候補の探索が主な目的である。観測性能については、これまでに気球実験や加速器実験で検証が行われており、シミュレーション計算や加速器実験結果から高い精度が確認されている。本論文では、これらの性能評価を基に CALETが取得するデータの解析手法について解説する。また運用中における CALETの地上システムや、データの取り扱いについてその概要を紹介する。

    CiNii

  • 気球搭載型CALET プロトタイプ(bCALET-2)による電子・ガンマ線観測(大気球研究報告)

    仁井田 多絵, 鳥居 祥二, 小澤 俊介, 笠原 克昌, 村上 浩之, 赤池 陽水, 植山 良貴, 伊藤 大二郎, 苅部 樹彦, 近藤 慧之輔, 九反 万里恵, 田村 忠久, 吉田 健二, 片寄 祐作, 清水 雄輝, 福家 英之

    宇宙航空研究開発機構研究開発報告   11   17 - 46  2012年03月

     概要を見る

    我々は,国際宇宙ステーション日本実験棟(きぼう)での高エネルギー宇宙線観測により,近傍加速源の発見や暗黒物質の探索を目指すCALorimetric Electron Telescope(CALET)の気球搭載型プロトタイプ観測装置(bCALET)を開発し,bCALET-1(2006 年)とbCALET-2(2009 年)の2 回にわたり観測実験を実施した.これらの観測は,CALET の先駆的観測として大気上層における電子・ガンマ線フラックスを求めることにより,観測装置の性能検証を行うことを目的としている.CALET の1/2 スケールモデルであるbCALET-2 は,入射粒子の飛跡を可視化するための解像型カロリメータ(IMaging Calorimeter : IMC)と,入射粒子のエネルギーを測定するための全吸収型カロリメータ(Total AbSorption Calorimeter : TASC)から構成され,1 - 100 GeV の領域で,電子・ガンマ線の識別とエネルギー測定が可能である.気球観測は2009 年8 月27 日,北海道のJAXA 大樹航空宇宙実験場で行われ,高度35 km における約2.5 時間の観測の結果,約12,000 例の宇宙線イベントを取得した.加速器実験やシミュレーション計算の結果を用いた,エネルギー較正,飛跡再構成,バックグラウンド除去などのデータ解析により,電子・ガンマ線それぞれについてエネルギースペクトルが求められている.この結果は,bCALET-1 やBETS(1998 年)などのこれまでの観測結果や計算に基づく予測値ともよく一致しており,今後のCALET の開発において大きな意義を持つ.

    CiNii

  • 国際宇宙ステーション搭載用電子,ガンマ線観測装置(CALET)の基礎開発

    鳥居祥二, 小澤俊介, 清水雄輝, 田村忠久, 赤池陽水, 植山良貴

    東北大学電子光理学研究センター核理研研究報告   42/43  2011年

    J-GLOBAL

  • 宇宙線観測装置CALETのフロントエンド回路の耐放射線性能

    田村忠久, 日比野欣也, 奥野祥二, 鳥居祥二, 清水雄輝, 赤池陽水, 平晃一, 日高健, 福田康博, 吉田賢二, 片寄祐作, CHEN D., 内堀幸夫, 北村尚, 山岡和貴

    NIRS-M (National Inst. of Radiological Sciences)   ( 214 )  2008年

    J-GLOBAL

▼全件表示

共同研究・競争的資金等の研究課題

  • 宇宙線原子核の直接観測による銀河宇宙線の加速・伝播機構の研究

    日本学術振興会  科学研究費助成事業 基盤研究(C)

    研究期間:

    2021年04月
    -
    2024年03月
     

    赤池 陽水

     概要を見る

    国際宇宙ステーションに搭載した宇宙線観測機CALETは、2015年10月から観測を開始し、現在まで6年以上の安定的な観測を継続している。検出器は大きな不具合なく観測初期とほぼ変わらない状態を維持しており、効率的な運用の元で高精度なデータを蓄積を継続している。本研究の目的は、銀河宇宙線の起源や加速・伝播機構の解明のため、CALETの観測データを基に宇宙線中の陽子から鉄に至る主要な原子核成分を精確に測定することである。
    本年度は、重い原子核の主成分である鉄のエネルギースペクトルを、10 GeV/nから2.0 TeV/nの広いエネルギー領域でスペクトルを求め、ベキは-2.60で一定であることを測定した。さらに、ニッケル成分についても8.8 GeV/nから240 GeV/nの領域で観測を行い、鉄と同様にスペクトルのベキ-2.51で一定であることが分かった。いずれも単一の検出器として、これまでで最も高統計なデータであり、またバックグラウンド混入の少ない高精度なデータである。また、鉄とニッケルのフラックス比は、エネルギーと共に一定であり、これらが類似の加速・伝播機構を示唆しているものと考えられる。この結果は、陽子や炭素、酸素といったより軽い原子核のスペクトルに一般的に見られているスペクトルの硬化が存在しないことを示しており、銀河宇宙線の加速・伝播機構のモデル検証に重要な情報を提供するものである。これらの成果は、それぞれPhysical Review Letters誌に掲載された。

  • 高エネルギー銀河宇宙線の直接観測による宇宙線の加速・伝播機構の研究

    日本学術振興会  科学研究費助成事業 研究活動スタート支援

    研究期間:

    2020年09月
    -
    2022年03月
     

    赤池 陽水

     概要を見る

    本研究は、荷電粒子観測による初めての宇宙線加速源の同定と宇宙暗黒物質の間接探索を目的として、国際宇宙ステーションに搭載した宇宙線観測機CALETの観測データを基に10 TeV領域に至る精確な宇宙線電子のエネルギースペクトルの導出を目指すものである。CALETは2015年10月から観測を開始し、2021年末までに6年以上の安定的な長期間観測を継続している。宇宙線電子成分の精確な測定のためには、電子の1000倍以上存在する陽子との選別性能の向上と、仔細なエネルギー較正が不可欠である。本年度は、これまでに選別した3 TeV以上の電子候補の各イベントについて、シミュレーション計算を基にLikelihoodやBDTによる多変量解析から電子らしさを評価し、粒子選別性能の向上を図った。また6年間の観測量に基づく5 TeVまでのエネルギースペクトルを導出し、この成果を宇宙線国際会議にて発表した。
    並行して行なった原子核観測では重い原子核である鉄とニッケルのエネルギースペクトルを導出した。これらのエネルギースペクトルは、陽子や炭素、酸素などの軽原子核で見られる数100 GeV/n領域のスペクトル硬化の兆候は存在せず、単一のべきであることが分かった。また鉄のニッケルのスペクトル比は一定であり、類似した加速・伝播機構を示唆しているものと考えられる。これらは軽核のスペクトルと合わせて理論モデルの構築に重要な基礎データとなる。この成果はそれぞれPhysical Review Letters誌から発表した。

  • 宇宙線電子観測の高精度化による宇宙線起源の解明

    日本学術振興会  科学研究費助成事業 若手研究(B)

    研究期間:

    2015年04月
    -
    2016年03月
     

    赤池 陽水

     概要を見る

    国際宇宙ステーションにおける宇宙線観測実験CALETは、宇宙線の起源や加速・伝播機構の解明を目的に、GeVからTeVの高エネルギー領域における宇宙線観測を実施している。CALETの検出器は平成27年8月に宇宙ステーション補給機「こうのとり」によって国際宇宙ステーションに搭載され10月から観測を開始した。所期の目的であるTeV領域の電子観測に成功し、高統計のエネルギースペクトルの導出に向けて長期間の観測を行っている。
    本研究では、精確なエネルギースペクトルの導出に向けて、CALETの取得データの詳細な解析を実施した。打ち上げ前に地上で取得した宇宙線ミューオンやテストパルス、及び宇宙ステーション搭載後に機上で収集した宇宙線のデータを基に、検出器全チャンネルの応答が打上前後で変化せず正常な応答を示していることを確認した。また長期間の定常観測に向けて、軌道上の観測環境に応じた観測条件の最適化を実施した。軌道上で取得したデータを基に検出器のエネルギー較正を実施するとともに、取得イベントのエネルギーや粒子種の再構成を実施し、CALETがTeV領域の電子成分のイベントを取得していることを示した。さらに陽子から鉄までの原子核、及びガンマ線が検出されていることを示した。これらの成果を基に、CALET実験は正常に初期運用を終了し、定常運用への移行を達成している。今後高統計・高精度なエネルギースペクトルの導出に向け、長期間の観測を継続すると共にデータ解析の高精度化を図る予定である。

  • 高エネルギー宇宙電子・ガンマ線観測による近傍加速源・暗黒物質の研究

    日本学術振興会  科学研究費助成事業 特別研究員奨励費

    研究期間:

    2012年04月
    -
    2015年03月
     

    赤池 陽水

     概要を見る

    銀河宇宙線の起源や加速・伝播機構の解明に向けて、国際宇宙ステーションにおける宇宙線観測実験CALETの装置開発を進めている。本研究では、シミュレーション計算や加速器ビーム実験を通じて装置性能の検証を進めてきた。またフライトモデルの製作に伴い、地上における各種動作試験や較正実験を行った。
    (1) シミュレーション計算による観測性能評価と軌道上における検出器較正手法の開発 軌道上における検出器の出力較正のため、陽子やヘリウムを利用した較正手法を検討している。シミュレーション計算を基に、出力較正に利用可能な最小電離損失粒子の選別手法を開発し、またイベントレートを見積もることにより、軌道上において現実的な時間で較正可能であることを示した。
    (2) フライトモデルの地上較正試験 CALETのフライト品の完成に伴い、検出器の組上げ試験、システム試験、熱真空試験等を実施した。各過程において、テストパルスやペデスタルのノイズレベルの評価、宇宙線ミューオンを利用した動作確認等を行ってきた。最終的なエネルギー較正に必要となる信号応答の基礎データの取得についても、紫外線パルスレーザー光を利用して全チャンネルの較正試験を実施した。
    (3) CERN-SPSにおける重粒子ビーム実験 CALETのフライトモデルと同じ構造をもつ熱構造モデルを用いて、欧州原子核研究機構CERNのSPS加速器においてArの破砕核を利用した加速器実験を実施した。この実験では、初めてカロリメータによるシャワー粒子の出力応答を検証することができたため、後方散乱の影響を含む電荷測定性能、エネルギー測定性能の検証を行った。今後詳細な解析を進め、CALETに最適なハドロン相互作用モデルの検証も行う。

  • 宇宙における高エネルギー粒子の生成・加速機構の実験的研究

    日本学術振興会  科学研究費助成事業 特別研究員奨励費

    研究期間:

    2009年
    -
    2011年
     

    赤池 陽水

     概要を見る

    本研究の目的は、高エネルギー宇宙線電子成分の観測により、近傍加速源や暗黒物質の探索を行うことである。このために、電子観測に最適な検出器を開発し、国際宇宙ステーション(International Space Station:ISS)における本格的な宇宙線観測計画(CALorimetric Electron Telescope:CALET)を進めている。高精度な電子観測を実現するためには、検出器に優れたエネルギー測定性能とバックグラウンドとなる陽子との強力な粒子識別性能が要求される。CALIETはこれらを実現するために厚いカロリメータ型の検出器を採用しており、これまでにシミュレーション計算を通じて、潜在的に高い観測能力を持つことを示している。本年度はこれらを実証するために、欧州原子核機構(CERN)におけるSPS加速器を用いたビーム試験を実施した。電子10-290GeV、陽子30-350GeVのビームをCALETのプロトタイプとなる検出器に照射し、シャワーの粒子数分布やエネルギー分解能、粒子識別において重要なパラメータとなるシャワーの横拡がりや遷移曲線について、電子、陽子の各粒子、各エネルギーにおける実験データの解析を進めている。これらの実験データは、CALETにおける開発要素の技術実証やISSにおける観測性能の実証に加えて、シミュレーション計算で再現することにより、CALETの解析手法の検証やシミュレーション計算自体の精度向上の点で大きな成果が得られている。また今回のビーム試験では、高統計の陽子イベントを取得しており、今後さらに詳細に解析を進めることで、シミュレーション計算において最も不定性の大きいハドロン相互作用モデルについて、CALETに最も適したモデル選別の検証も実施する予定である。

学内研究費(特定課題)

  • 国際宇宙ステーションにおける宇宙線高精度観測による宇宙線電子起源の解明

    2015年  

     概要を見る

    本研究は、2015年8月に国際宇宙ステーションに搭載された宇宙線観測装置CALETによる観測データを基に、高エネルギー宇宙線の起源や加速・伝播機構の解明を目指している。本研究では打ち上げ前後の地上試験や初期運用時の収集データの解析を通じて、検出器が性能要求を満たす観測性能を有しており、打上げ前後で変わらない観測性能を示していることを確認した。また観測データの解析を実施し、所期の目的であるTeV領域の宇宙線電子成分の直接観測を達成した。本研究で得られた研究成果は、今後の詳細なデータ解析の基礎として重要であり、精緻なエネルギースペクトルの導出のため、高統計なデータ収集及びデータ解析を今後実施する予定である。