EPJ Web of Conferences 208, 13001 (2019)
https://doi.org/10.1051/epjconf/201920813001

The CALorimetric Electron Telescope (CALET) on the International Space Station: Results from the First Two Years of Operation

¹ Waseda Research Institute for Science and Engineering, Waseda University, Japan
² JEM Utilization Center, Human Spaceflight Technology Directorate, Japan Aerospace Exploration Agency, Japan
³ Department of Physics, University of Florence, Italy
⁴ INFN Sezione di Florence, Italy
⁵ Department of Physics, University of Maryland, USA
⁶ Astroparticle Physics Laboratory, NASA/GSFC, USA
⁷ Institute for Cosmic Ray Research, The University of Tokyo, Japan
⁸ Department of Physical Sciences, Earth and Environment, University of Siena, Italy
⁹ INFN Sezione di Pisa, Italy
¹⁰ Department of Physics, Washington University, USA
¹¹ Heliospheric Physics Laboratory, NASA/GSFC, USA
¹² Department of Physics and Astronomy, Louisiana State University, USA
¹³ Institute of Applied Physics (IFAC), National Research Council (CNR), Italy
¹⁴ Department of Physics and Astronomy, University of Padova, Italy
¹⁵ INFN Sezione di Padova, Italy
¹⁶ University of Rome “Tor Vergata”, Italy
¹⁷ INFN Sezione di Rome “Tor Vergata”, Italy
¹⁸ Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Japan
¹⁹ CRESST and Astroparticle Physics Laboratory NASA/GSFC, USA
²⁰ Kanagawa University, Japan
²¹ Faculty of Science and Technology, Graduate School of Science and Technology, Hirosaki University, Japan
²² Yukawa Institute for Theoretical Physics, Kyoto University, Japan
²³ National Institute of Polar Research, Japan
²⁴ Faculty of Engineering, Division of Intelligent Systems Engineering, Yokohama National University, Japan
²⁵ Faculty of Science, Shinshu University, Japan
²⁶ Hakubi Center, Kyoto University, Japan
²⁷ Department of Astronomy, Graduate School of Science, Kyoto University, Japan
²⁸ College of Science and Engineering, Department of Physics and Mathematics, Aoyama Gakuin University, Japan
²⁹ Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization, Japan
³⁰ University of Pisa, Italy
³¹ Department of Electrical and Electronic Systems Engineering, National Institute of Technology, Ibaraki College, Japan
³² Department of Astronomy, University of Maryland, USA
³³ Department of Physical Sciences, College of Science and Engineering, Ritsumeikan University, Japan
³⁴ Global Center for Science and Engineering, Faculty of Science and Engineering, Waseda University, Japan
³⁵ RIKEN, Japan
³⁶ Department of Physics and Astronomy, University of Denver, USA
³⁷ ASI Science Data Center (ASDC), Italy
³⁸ College of Industrial Technology, Nihon University, Japan
³⁹ Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo, Japan
⁴⁰ Institute for Cosmic Ray Research, Japan
⁴¹ School of Advanced Science and Engineering, Waseda University, Japan
⁴² Division of Mathematics and Physics, Graduate School of Science, Osaka City University, Japan
⁴³ National Institutes for Quantum and Radiation Science and Technology, JAPAN
⁴⁴ Nagoya University, Japan
⁴⁵ College of Science, Ibaraki University, Japan
⁴⁶ Department of Electronic Information Systems, Shibaura Institute of Technology, Japan

^* e-mail: yoichi.asaoka@aoni.waseda.jp

Published online: 10 May 2019

Abstract

The CALorimetric Electron Telescope (CALET) space experiment, which has been developed by Japan in collaboration with Italy and the United States, is a high-energy astroparticle physics mission on the International Space Station (ISS). The primary goals of the CALET mission include investigation of possible nearby sources of high-energy electrons, detailed study of galactic cosmic-ray acceleration and propagation, and search for dark matter signatures. With a long-term observation onboard the ISS, the CALET experiment measures the flux of cosmic-ray electrons (including positrons) up to 20 TeV, gamma-rays to 10 TeV, and nuclei up to 1,000 TeV based on its charge separation capability from Z = 1 to 40. Since the start of science operation in mid-October, 2015, a continuous observation has been maintained without any major interruptions. The number of triggered events over 10 GeV is nearly 20 million per month. By using the data obtained during the first two-years, here we present a summary of the CALET observations: 1) Electron+positron energy spectrum, 2) Nuclei analysis, 3) Gamma-ray observation with a characterization of the on-orbit performance. The search results for the electromagnetic counterparts of LIGO/Virgo gravitational wave events are also discussed.