Development of a Pressurized Helium Scintillating Calorimeter for AntiMatter Identification.

The detection of low-energy antideuterons in Cosmic Rays (CRs) addresses crucial questions regarding the antimatter asymmetry in the Universe and the potential identification of annihilating Dark Matter particles in the galactic halo. The Pressurized Helium Scintillating Calorimeter for AntiMatter Identification (PHeSCAMI) project aims to explore a novel signature for identifying antideuterons and antiprotons in CRs through delayed annihilations within a helium target. We present the performance evaluation of a large-acceptance detector design for PHeSCAMI, including the development of a possible trigger logic and the estimation of the expected background rate using Monte Carlo simulations based on the Geant4 toolkit. Additionally, we investigate the performance of the FB118 Wavelength Shifter (WLS), manufactured by "Glass to Power", in a two-stage system designed to convert VUV (80 nm) scintillation light from the helium into visible light.