标题：The RICH detector of AMS-02: 5 years of operation in space
作者：Liu, Hu; Casaus, J.; Giovacchini, F.; Oliva, A.; Xia, X.
作者机构：[Liu, Hu; Casaus, J.; Giovacchini, F.; Oliva, A.] Ctr Invest Energet Medioambientales & Tecnol CIEM, E-28040 Madrid, Spain.; [Liu, Hu] Huazhong Univ 更多
会议名称：9th International Workshop on Ring Imaging Cherenkov Detectors (RICH)
会议日期：SEP 05-09, 2016
来源：NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
关键词：Cosmic Rays; CRs Isotopic Composition; CRs Helium Isotopes; RICH; AMS-02
摘要：AMS-02 is a high-energy particle physics magnetic spectrometer installed on the International Space Station since May 2011, and operating continuously since then. The AMS-02 Ring Imaging Cerenkov counter ( RICH) is a specialised sub-detector for the precise measurement of the particle velocity beta with a resolution of Delta beta/beta = 0.7(2.4) x 10(-3) for helium nuclei passing through the Aerogel (NaF) radiator. From the emitted photon counting the particle absolute charge magnitude vertical bar Z vertical bar can be estimated with an uncertainty of 0.3 charge units for helium nuclei. In 5 years of operations the optical properties of the RICH had no significant degradation and the performances of the detector have been stable in time.; By means of the simultaneous use of the Silicon Tracker and the RICH, AMS is able to investigate the isotopic composition of cosmic rays in the kinetic energy range from few GeV/n to similar to 10 GeV/n for elements with charge vertical bar Z vertical bar up to 4 with unprecedented statistics. The precise measurement of cosmic rays light nuclei isotopes ratio, such as He-3/He-4 and Be-10/Be-9, provide important constraints to the free parameters in the models for cosmic rays propagation in our Galaxy. In particular the mass distinction between He-3 and He-4 needed for the measurement of the He-3/He-4 flux ratio is obtained by statistical methods. The excellent simulation of the AMS detector provides the precise description needed for this analysis. Moreover, the use of the geomagnetic field for selecting control samples of CRs with enhanced abundances of heavy isotopes provides an independent tool for the study of the light nuclei isotopic composition with AMS.