Measurements of Light Emissions in TeO₂ Crystals

CUPID (CUORE Upgrade with Particle ID) is a next-generation bolometric experiment that will search for 0νββ decay with enhanced sensitivity through the ability to distinguish between 0νββ events and α backgrounds by detecting light emissions. To achieve this, it is important to characterize the amount of Cherenkov radiation that we can expect to detect, as well as any other luminescence that particles may cause in the detector material. The CHErenkov/Scintillation Separation setup (CHESS) is suitable for targets with small expected light yields, has the ability to detect light with high time resolution, and is sensitive to the directionality of light escaping the target material. We use this setup to measure and quantify the amount of Cherenkov and scintillation-like light emitted in TeO₂ crystals, one of the primary candidate materials for the detector mass of CUPID.