Updates to Geant4 Simulations for TIGERISS

The Trans-Iron Galactic Element Recorder for the International Space Station (TIGERISS) is an ultra-heavy galactic cosmic ray (UHGCR) detector planned for installation at the Columbus SOX location of the International Space Station (ISS) in 2027. TIGERISS improves on previous instruments by using silicon strip detectors (SSDs) to achieve greater linearity in signal response over an expanded dynamic range from 5B to 82Pb

and silicon photomultipliers (SiPMs) for a more compact readout profile and to avoid the need for  high voltage. Geant4 is used to predict instrument performance, such as energy ranges and geometry factors. We present top-of-instrument energy thresholds for aerogel and acrylic Cherenkov detectors as a function of charge and angle. Previous simulations were for a 9x10 SSD geometry, while the current proposed detector has a 9x9 geometry, which requires new simulations to understand the geometry factor. Additional work focuses on creating a simulated data set to model expected results after launch.