A Study on PbMoO4 Phonon-Scintillation Detection with MMC Readouts for a Neutrinoless Double Beta Decay Search.

The advanced Mo-based rare process experiment (AMoRE) is an international project searching for the neutrinoless double beta ( 0 ν β β ) decay of 100 Mo using low-temperature calorimetric detection of heat and light signals based on magnetic microcalorimeter (MMC) readouts. Li 2 MoO 4 crystals have been considered as the main target crystals for the second phase of the AMoRE project, which aims to use 100 kg of 100 Mo. However, the hygroscopicity of Li 2 MoO 4 requires moistureless processes during surface treatment, storage, detector assembly, and installation. PbMoO 4 crystals are nonhygroscopic and exhibit high scintillation efficiency, often leading to high particle discrimination power in the phonon channel via pulse-shape analysis and light/heat ratio variation. A low-temperature detector setup with a 1 cm 3 cubic crystal of PbMoO 4 was prepared for simultaneous heat and light detection based on MMC readouts. After study of internal background control using archeological Pb, PbMoO 4 crystal can be a promising candidate crystal. We present a feasibility study of PbMoO 4 crystals for a 0 ν β β experiment. [ABSTRACT FROM AUTHOR]