Results From The Calorimetric Electron Telescope On The International Space Station


Charge distributions from the combined charge measurement of the two CHD layers in the elemental region between Ca and Ge. Events are selected with 100 < ETASC < 125 GeV. Flight data (black dots) are compared with Monte Carlo samples comprising chromium, manganese, iron, cobalt and nickel. Titanium and vanadium are not included in the MC because their contamination to iron data is negligible. In Fig. S1 of the SM [51] an enlarged version of this figure is shown, as well as the distribution for the bin 501 < ETASC < 631 GeV

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.

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

Comments: main text: 7 pages, 4 figures; supplemental material: 10 pages, 12 figures, 1 table. arXiv admin note: text overlap with arXiv:2012.10319
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Journal reference: Phys. Rev. Lett. 126, 241101 - Published 14 June 2021
DOI: 10.1103/PhysRevLett.126.241101
Cite as: arXiv:2106.08036 [astro-ph.HE] (or arXiv:2106.08036v1 [astro-ph.HE] for this version)
Submission history
From: Caterina Checchia Dr.
[v1] Tue, 15 Jun 2021 10:44:49 UTC (126 KB)
https://arxiv.org/abs/2106.08036

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