Geant4 Simulations of Interaction and Energy Losses for TIGERISS

The Trans-Iron Galactic Element Recorder for the International Space Station (TIGERISS) is an ultra-heavy galactic cosmic ray (UHGCR) detector that is planned to be installed on the International Space Station (ISS) in 2027. TIGERISS is an evolution of the TIGER and SuperTIGER balloon-borne projects that have the goal of understanding the models of GCR origins. TIGERISS will improve on previous instruments using silicon strip detectors (SSDs) and silicon photomultipliers (SiPMs) to achieve greater charge resolution and detector linearity over an expanded dynamic range to measure GCRs from 5B to 82Pb. Using Geant4, we model the new TIGERISS instrument and simulate UHGCR interactions to generate corrections for each element as a function of incidence angle for TIGERISS. We derive corrections for nuclear interactions to generate top-of-instrument (TOI) abundances by tracking secondary particle production. The simulations determine TOI energies needed to trigger the instrument by depositing enough energy in the bottom detector to be above threshold in the acrylic and silica aerogel Cherenkov detectors.