Speaker
Description
DarkSide-20k is a next-generation liquid argon experiment designed for direct dark matter searches at the Gran Sasso National Laboratory. However, cosmogenic backgrounds impose strict requirements on veto performance, making the 650-ton Outer Veto subsystem essential for protecting the WIMP signal region. Reliable operation of the muon veto requires quantitative understanding of its optical response and material-dependent performance.
To address these requirements, we develop and apply a Geant4-based Monte Carlo optical simulation that quantifies detector-level response derived from simulated photosensor signals. We compare multiple candidate wavelength-shifting and reflective materials to study their impact on photon collection and subsystem uniformity. We calculate average light yield and channel-level response distributions to evaluate global efficiency of the veto system.
These results define the optical limits of the muon veto and provide quantitative input for future efficiency and background rejection studies, directly informing development of the Outer Veto subsystem.