Description
CUPID is a proposed next-generation experiment that will search for neutrinoless double-β (0νββ) decay using light-emitting (scintillation or Cherenkov) crystals operated as low-temperature calorimeters close to ∼10mK. It will leverage the crystal's energy loss mechanism to tag particle type by simultaneously measuring thermal and light signals. We will use an auxiliary low-temperature calorimeter to detect light with high photon collection efficiency. The light detectors must have a low energy threshold (~100eV) and good timing resolution to tag α background and 2νββ pile-up events in the region of interest. The light detectors are crucial to reach the CUPID background goal of <1E-4 counts/(keV.kg.yr) for its baseline design. This work will discuss the baseline design of the CUPID light detectors and the R&D status of a future upgrade with transition-edge sensor (TES) based light detectors which may further help suppress the pile-up background.
