Adriani O, Akaike Y, Asano K, Asaoka Y, Berti E, Bigongiari G, Binns W R, Bongi M, Brogi P, Bruno A, Buckley J H, Cannady N, Castellini G, Checchia C, Cherry M L, Collazuol G, Ebisawa K, Fuke H, Gonzi S, Guzik T G, Hams T, Hibino K, Ichimura M, Ioka K, Ishizaki W, Israel M H, Kasahara K, Kataoka J, Kataoka R, Katayose Y, Kato C, Kawanaka N, Kawakubo Y, Kobayashi K, Kohri K, Krawczynski H S, Krizmanic J F, Link J, Maestro P, Marrocchesi P S, Messineo A M, Mitchell J W, Miyake S, Moiseev A A, Mori M, Mori N, Motz H M, Munakata K, Nakahira S, Nishimura J, de Nolfo G A, Okuno S, Ormes J F, Ospina N, Ozawa S, Pacini L, Papini P, Rauch B F, Ricciarini S B, Sakai K, Sakamoto T, Sasaki M, Shimizu Y, Shiomi A, Spillantini P, Stolzi F, Sugita S, Sulaj A, Takita M, Tamura T, Terasawa T, Torii S, Tsunesada Y, Uchihori Y, Vannuccini E, Wefel J P, Yamaoka K, Yanagita S, Yoshida A, Yoshida K
Department of Physics, University of Florence, Via Sansone, 1, 50019 Sesto, Fiorentino, Italy.
INFN Sezione di Florence, Via Sansone, 1, 50019 Sesto, Fiorentino, Italy.
Phys Rev Lett. 2021 Jun 18;126(24):241101. doi: 10.1103/PhysRevLett.126.241101.
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.
量热电子望远镜（CALET）自2015年起在国际空间站上运行，在很宽的能量区间内收集了大量宇宙射线铁样本。在本快报中，给出了每核子动能在10 GeV/n至2.0 TeV/n范围内的铁谱测量结果，从而得以将铁纳入由太空仪器以前所未有的精度进行研究的元素列表中。该测量基于2016年1月至2020年5月期间进行的观测。CALET仪器能够通过测量单个核素的电荷来识别它们，其动态范围远远超出铁（高达原子序数Z = 40）。能量由一个等效总厚度为1.2个质子相互作用长度的均匀量热计测量，量热计之前有一个薄的（3个辐射长度）成像部分，用于提供跟踪和能量采样。描述了数据的分析以及系统不确定性的详细评估，并将结果与先前实验的结果进行了比较。观测到的微分谱在误差范围内与先前实验一致。在50 GeV/n至2 TeV/n的区域内，我们目前的数据与谱指数为 -2.60±0.03的单一幂律相符。
