@article{38dc835c1c3b47dd9bfdc98f4f1df344,
title = "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",
abstract = "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.",
author = "{(CALET Collaboration)} and O. Adriani and Y. Akaike and K. Asano and Y. Asaoka and E. Berti and G. Bigongiari and Binns, {W. R.} and M. Bongi and P. Brogi and A. Bruno and Buckley, {J. H.} and N. Cannady and G. Castellini and C. Checchia and Cherry, {M. L.} and G. Collazuol and K. Ebisawa and H. Fuke and S. Gonzi and Guzik, {T. G.} and T. Hams and K. Hibino and M. Ichimura and K. Ioka and W. Ishizaki and Israel, {M. H.} and K. Kasahara and J. Kataoka and R. Kataoka and Y. Katayose and C. Kato and N. Kawanaka and Y. Kawakubo and K. Kobayashi and K. Kohri and Krawczynski, {H. S.} and Krizmanic, {J. F.} and J. Link and P. Maestro and Marrocchesi, {P. S.} and Messineo, {A. M.} and Mitchell, {J. W.} and S. Miyake and Moiseev, {A. A.} and M. Mori and N. Mori and Motz, {H. M.} and K. Munakata and S. Nakahira and K. Yoshida",
note = "Funding Information: We gratefully acknowledge JAXA{\textquoteright}s contributions to the development of CALET and to the operations aboard the JEM-EF on the International Space Station. We also wish to express our sincere gratitude to Agenzia Spaziale Italiana (ASI) and NASA for their support of the CALET project. This work was supported in part by JSPS Grant-in-Aid for Scientific Research (S) No. 26220708 and No. 19H05608, JSPS Grant-in-Aid for Scientific Research (B) No. 17H02901, JSPS Grant-in-Aid for Research Activity Start-up No. 20K22352 and by the Ministry of Education, Culture, Sports, Science and Technology-Supported Program for the Strategic Research Foundation at Private Universities (No. S1101021) at Waseda University. The CALET effort in Italy is supported by ASI under Agreement No. 2013-018-R.0 and its amendments. The CALET effort in the United States is supported by NASA through Grants No. NNX16AB99G, No. NNX16AC02G, and No. NNH14ZDA001N-APRA-0075. We thank Professor G. Morlino for theoretical discussions on the iron spectral shape. Publisher Copyright: {\textcopyright} 2021 authors. Published by the American Physical Society.",
year = "2021",
month = jun,
day = "18",
doi = "10.1103/PhysRevLett.126.241101",
language = "English",
volume = "126",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "24",
}