Title

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

Authors

O. Adriani, Università degli Studi di Firenze
Y. Akaike, Waseda University
K. Asano, The University of Tokyo
Y. Asaoka, The University of Tokyo
M. G. Bagliesi, Università degli Studi di Siena
E. Berti, Università degli Studi di Firenze
G. Bigongiari, Università degli Studi di Siena
W. R. Binns, Washington University in St. Louis, McDonnell Center for the Space Sciences
M. Bongi, Università degli Studi di Firenze
P. Brogi, Università degli Studi di Siena
A. Bruno, NASA Goddard Space Flight Center
J. H. Buckley, Washington University in St. Louis, McDonnell Center for the Space Sciences
N. Cannady, University of Maryland, Baltimore (UMB)
G. Castellini, Consiglio Nazionale delle Ricerche
C. Checchia, Università degli Studi di Firenze
M. L. Cherry, Louisiana State University
G. Collazuol, Università degli Studi di Padova
K. Ebisawa, JAXA Institute of Space and Astronautical Science
H. Fuke, JAXA Institute of Space and Astronautical Science
S. Gonzi, Università degli Studi di Firenze
T. G. Guzik, Louisiana State University
T. Hams, University of Maryland, Baltimore (UMB)
K. Hibino, Kanagawa University
M. Ichimura, Hirosaki University
K. Ioka, Yukawa Institute for Theoretical Physics
W. Ishizaki, The University of Tokyo
M. H. Israel, Washington University in St. Louis, McDonnell Center for the Space Sciences
K. Kasahara, Shibaura Institute of Technology
J. Kataoka, Waseda University
R. Kataoka, National Institute of Polar Research
Y. Katayose, Yokohama National University
C. Kato, Shinshu University
N. Kawanaka, Kyoto University

Document Type

Article

Publication Date

12-18-2020

Abstract

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.

Publication Source (Journal or Book title)

Physical Review Letters

This document is currently not available here.

Share

COinS