Intrinsic and radiation-induced colour centers in PbWO4 crystal
钨酸铅晶体的本征色心和辐照诱导色心

Based on the defect chemistry and crystal structures of PbWO 4 (PWO) crystal,the microstructure of PWO crystal after high-temperature annealing was studied by optical absorption spectra,extended X-ray absorption fine structure (EXAFS) and refined X-ray diffraction (XRD) technigues.The variation of defect concentration before and after annealing has been observed.Accordingly,we proposed that the origin of the intrinsic 350nm absorption band in as-grown crystals was ascribed to the V - F hole centers.The intensity of the absorption band of colour centers in the ultraviolet region was found to be dependent on the concentration difference of the Pb and O vacancies:V Pb]-V O].Also,we suggested that the 420nm absorption band originates from the V 0 F dihole centers,based on the experimental results of formation of radiation-induced colour centers and their polarized absorption spectra.The feasibility of the proposed model of colour centers was also discussed.