Luminescence and scintillation characterization of PbMoO ₄ crystal for neutrinoless double beta decay search

A PbMoO ₄ single crystal with optically good quality and crack free, bulk crystal is grown by the low thermal gradient Czochralski method. The luminescence and scintillation properties of the grown crystal are measured under the excitations by 4.4 eV UV, 662 keV γ, 5.5 MeV α, and β in the temperature range of 10–300 K. The light yield under UV and β excitations are found to enhance down to 10 K, however quenched below 50 K under γ and α excitations. The major luminescence and scintillation decay time constants are found to be 20 μs, 18 μs, and 28 μs, respectively, with 4.4 eV, 662 keV γ, and 5.5 MeV α excitations at 10 K. The thermally stimulated luminescence (TSL) glow curve measured after X-ray irradiation at 10 K, shows three overlapping peaks in the temperature range of 10–70 K. The TSL kinetic parameters such as trap depth (E) and frequency factor (s) are determined by using general order kinetics and found to be, 41.5 K (peak-1), 35 meV, 3.95 × 10 ² s ⁻¹ , 51.1 K (peak-2), 121 meV, 4.31 × 10 ¹⁰ s ⁻¹ , and 56.8 K (peak-3), 123 meV, 3.32 × 10 ⁹ s ⁻¹ . The quenching of scintillation light yield under α and γ excitations at lower temperature is due to the self-trapping of electrons at (MoO ₄ ) ^2- molecular complex.