Multithreaded Monte Carlo Simulations of the ISS-CREAM Instrument

The Cosmic Ray Energetics And Mass experiment for the International Space Station (ISS-CREAM) is designed to directly measure the cosmic ray energy spectra from Z = 1–26 at high energies ranging from ~10¹² to ~10¹⁵ eV. Described from top to bottom, the ISS-CREAM instrument comprises four layers of a finely-segmented silicon charge detector (SCD), two dense carbon targets (C-Targets), a tungsten scintillating-fiber calorimeter (CAL), top and bottom counting detectors (TCD/BCD), and a boronated scintillator detector (BSD). The SCD measures the charge of incident cosmic rays, the C-Targets induce hadronic interactions, the CAL collects energy deposit data and provides a high-energy trigger, the TCD/BCD provide a low-energy trigger, and the BSD distinguishes electrons from other nuclei. Cosmic ray interactions in the ISS-CREAM instrument are simulated with the Geant4 Monte Carlo simulation toolkit. For this presentation, multithreaded (MT) data generation was newly implemented in the ISS-CREAM simulation to simulate isotropic proton, helium, and carbon nuclei at incident energies from 1 TeV to 1 PeV. The calorimeter response, selection efficiency, position resolution, and charge distribution will be presented.