The origin of centres responsible for green emission, their excited-state disintegration and the origin of defects created by UV radiation, were studied in crystals with various Mo6+ concentrations, as well as for Y3+ and Nb5+ co-doped PbWO4:Mo. Following selective UV irradiation, TSL appeared to be due to the recombination of defects formed after exciton and defect-related state disintegration. The TSL intensity versus irradiation energy (3.4-4.3eV) and irradiation temperature (80-180K) were measured. For exciton state disintegration, the activation energy was about 0.1eV while, for defect states, the disintegration activation energy was 0.03 to 0.36eV. At below 130K, temperature-independent defect creation was observed in some crystals. Defects with various origins existed in Mo-doped crystals, and different defects could coexist in the same sample. Free electron release into the conduction band, and charge-transfer processes, could contribute to photo-thermally stimulated defect creation.

Defects in UV-Irradiated PbWO4:Mo Crystals Monitored by TSL Measurements. P.Bohacek, P.Fabeni, A.Krasnikov, M.Nikl, G.P.Pazzi, C.Susini, S.Zazubovich: Physica Status Solidi C, 2005, 2[1], 547-50