Measurements of cosmic-ray proton and helium spectra from the ISS-CREAM experiment

Choi, Gwangho; Seo, E. S.; Aggarwal, S.; Amare, Y.; Angelaszek, D.; Bagga, A.; Bowman, D. P.; Chen, Y. C.; Copley, M.; Derome, L.; Dorris, Z. M.; Eraud, L.; Han, J. H.; Haque, A.; Huh, H. G.; Jeong, S.; Kang, S. C.; Kim, H. J.; Kim, K. C.; Kim, M. H.; Lee, J.; Lee, M. H.; Lee, M. J.; Lundquist, J. P.; Lutz, L.; Maricic, S.; Menchaca-Rocha, A.; Ofoha, O.; Park, H.; Park, I. H.; Park, J. M.; Pandey, S.; Picot-Clemente, N.; Scrandis, R.; Weinmann, R. P.; Wu, H.; Wu, J.; Yoon, Y. S.; Zhang, H. G.

doi:10.22323/1.501.0028

Abstract

The Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) payload was developed to measure the elemental spectra for a charge range of Z = 1 to 26, with an energy range from ∼10^12 to ∼10^15eV. Launched in August 2017, the ISS-CREAM payload successfully collected data for 539 days until February 2019. The ISS-CREAM instrument consists of several particle detectors: a Silicon Charge Detector (SCD) for charge measurements and a calorimeter (CAL) with carbon targets for energy measurements. It also includes a top counting detector (TCD), a bottom counting detector (BCD), and a boronated scintillator detector (BSD) to help
separate electrons from protons. For this analysis, SCD and CAL were used for the charge and energy measurement, respectively, while TCD/BCD and CAL were used for the trigger. The ISS-CREAM proton spectrum has been reported in the energy range of 1.6 − 655 TeV. This
proton spectrum deviates from a single power-law, softening at ∼ 9 TeV. This study presents the preliminary helium spectrum from the ISS-CREAM experiment in the energy range of 6 TeV to ∼ 1.1 PeV.