STUDY ON THE SCINTILLATING PROPERTIES OF IONS DOPED LEAD TUNGSTATE SCINTILLATION CRYSTALS

PbWO4 and BaF2; PbWO4 were grown by multi-crucible temperature gradient system. The transmittance spectra and x-ray excited luminescence spectra of as-grown PbWO4, annealed PbWO4 and annealed BaF2 : PbWO4 were studied. The results reveal that these properties are related to the composition and growth arts of the crystals. The facts are complicated for the crystals annealing. In the wavelength range above 360nm, the transmittance for the annealed crystal is better than that of the as-grown crystal, while it is a little weaker than that of the as-grown crystal in the wavelength range of 320 similar to 360nm. For the x-ray excited luminescence spectra, the spectrum intensity of the annealed crystal is higher than that of as-grown crystal in the wavelength range above 380nm, while it is a little weaker than that of as-grown crystal in the wavelength range of 320 similar to 380nm. The doping ions improve the transmittance and the x-ray excited luminescence spectrum intensity. These phenomena are explained based on the relations of the defect, crystal growth arts and the optical Properties of these crystals. For the BaF2 : PbWO4 crystal, it's peak shape and intensity of x-ray excited luminescence spectrum are evidently changed than PbWO4 crystal. The phenomenon may relate to the fact that [WO4](2-) tetrahedron of the crystal is degenerated when it is doped with F- ions, and the degeneration will induce a new luminescent center.