Feasibility study of PbWO4 and PbMoO4 crystal scintillators for cryogenic rare events experiments

Scintillation properties of PbWO4 and PbMoO4 have been studied as potential cryogenic scintillators for rare event searches. The light output and decay kinetics of PbWO4 and PbMoO4 crystals for excitation with 241Am α particles were examined over the temperature range 7-300 K. The α/γ ratio was measured with a PbMoO4 crystal scintillator for 5.3 MeV α particles, and the ability to distinguish between signals induced by α particles and γ quanta by pulse shape discrimination was assessed for the PbMoO4 crystal scintillator at 77 K. The energy dependence of the quenching factor for oxygen, molybdenum, tungsten and lead ions at low energy was calculated using a semi-empirical approach with data from the α particle measurements. The study demonstrates the good potential of these scintillators for cryogenic dark matter search and double beta decay experiments.