Cryogenic Heat-Light Detection System for 1-cm³ Scintillating Crystals

We have developed a cryogenic heat and light detection system to investigate phonon and scintillation properties of scintillating crystals for rare event search experiments. The detector setup is designed to utilize a 1 × 1× 1 cm³ scintillating crystal as a target material. A 1.5× 1.5× 0.05 cm³ Ge wafer is used as the absorber of the light detection. Metallic magnetic calorimeters are employed to measure heat and scintillation-light signals of the scintillating crystal, simultaneously, at millikelvin temperatures. This measurement setup is motivated to characterize various types of scintillation crystals in a standard coupon size for a final selection of the crystal compounds to be used for a rare event search experiment. We present the first measurement for a calcium molybdate crystal doped with niobium in the test setup of heat-light detection. Clear particle identification was obtained in comparison of relative amplitude ratios of the phonon and scintillation signals. Moreover, alpha- and electron-induced events showed difference in their pulse shapes of phonon and scintillation signals. We discuss the usage of this setup for the AMoRE 0ν β β search experiment.