Brian Rauch - Topic: Cosmic ray detections with the TIGER family of instruments

The Trans-Iron Galactic Element Recorder (TIGER) family of instruments are designed to make the best single-element resolution measurements of the Ultra-Heavy Galactic Cosmic Rays (UHGCRs) to probe their origins and sources of nucleosynthesis. The TIGER and SuperTIGER stratospheric balloon-borne detectors have each had two successful flights from Antarctica, with TIGER making preliminary cosmic-ray (CR) abundance measurements through ₄₀Zr and SuperTIGER through ₅₆Ba. The successor to these instruments will be the TIGER for the International Space Station (TIGERISS), in development under the NASA Astrophysics Pioneers program with a planned 2027 launch, which will measure the abundances of individual CR elements from ₅B to ₈₂Pb with unprecedented charge resolution and detector linearity. TIGERISS will improve on the predecessor TIGER and SuperTIGER long-duration-balloon instruments by using silicon strip detectors (SSDs) in place of scintillator detectors for ionization energy measurements and using silicon photomultipliers (SiPMs) instead of photomultiplier tubes (PMTs) to read out the acrylic and silica aerogel Cherenkov-light-radiator detectors. The superior resolution of the SSDs over the scintillator detectors has been demonstrated in component accelerator tests at CERN, allowing TIGERISS to identify UHGCR nuclei with charge resolution σ_Z < 0.25. UHGCR observations cover those synthesized in stellar fusion and in s-process and r-process neutron capture nucleosynthesis, which will add to the multi-messenger effort to answer the question of the degree that r-process elements are synthesized in supernovae (SN) or Neutron Star Merger (NSM) events.