Preparing TIGERISS for the ISS: A Mission to Explore Cosmic Ray Origins and Heavy Element Nucleosynthesis

The Trans-Iron Galactic Element Recorder for the International Space Station (TIGERISS) is set to redefine our understanding of galactic cosmic rays through an ISS mission planned for launch in 2027. Building on the successes of the TIGER and SuperTIGER experiments, TIGERISS utilizes silicon detectors to significantly enhance measurement precision and expand the dynamic range, overcoming the limitations of traditional scintillator systems. Over a year-long mission, TIGERISS will measure cosmic ray abundances from boron (Z=5) to lead (Z=82), shedding light on the origins and acceleration mechanisms of high-energy particles. The instrument features crossed silicon strip detectors for trajectory and energy determination, along with Cherenkov light collection systems using silica aerogel and acrylic radiators. This combination is designed to achieve precise charge resolution (σZ < 0.25), ensuring accurate charge assignments across a wide range of elements. By exploring the composition of cosmic rays and their link to nucleosynthesis processes, TIGERISS will offer new insights into the roles of supernovae and neutron star mergers in r-process nucleosynthesis. The mission promises to enhance our understanding of cosmic ray phenomena and contribute valuable data to the growing field of multi-messenger astronomy, connecting astrophysics and nuclear physics.