ScholarWorks@성균관대학교

초록

The Cosmic Ray Energetics and Mass for the International Space Station (ISS-CREAM) was developed to carry out direct measurements of the energy spectra of high-energy cosmic rays, ranging from protons to iron nuclei. The experiment targeted cosmic rays in the energy range of ∼1012 to 1015 eV, with the goal of probing the origin, propagation and acceleration mechanisms of cosmic rays. The instrument consists of a tungsten scintillating-fiber Calorimeter for energy measurements and tracking, four layers of finely segmented Silicon Charge Detectors for charge measurements, and two additional detectors for electron/hadron separation. The Calorimeter also provides the main high energy physics trigger, while the Top and Bottom scintillator-based counting detectors provide an additional low energy trigger. For consistency with the balloon-borne CREAM experiment analyses, the GEANT3 package with the FLUKA hadronic model was used for the simulations. Simulations were also conducted using updated Geant4 and Geant4 multithreading models, and results of the three simulation versions are compared. The presented analysis focuses on isotropically generated helium nuclei events incident from the upper hemisphere onto the detector geometry. The Monte Carlo data analysis and its results, such as the detector efficiency, calorimeter energy response, position and charge resolutions, for the ISS-CREAM instrument and comparisons between software versions are presented.