Novosad S.S.,Ivan Franko National University of Lviv |
Kostyk L.V.,Ivan Franko National University of Lviv |
Novosad I.S.,Ivan Franko National University of Lviv |
Solskii I.M.,CARAT Scientific Research Company
Journal of Applied Spectroscopy | Year: 2010
We have studied thermally and photostimulated recombination processes in PbWO4 crystals in the temperature interval 90-295 K. We have shown that after x-ray excitation of the crystal at 90 K, the thermally stimulated luminescence curve shows a relatively intense peak at 110 K and weak peaks at about 173, 191, and 232 K. Exposure of the PbWO4 crystal to IR radiation after excitation by x-ray photons leads to the appearance of photostimulated flash luminescence, a significant decrease in the intensity of the 110 K peak, and a shift of that peak to the 116 K region. But long-wavelength illumination has less of an effect on the intensity and position of the higher temperature peaks. It is assumed that F- centers are formed in the PbWO4 crystal at 90 K during x-ray exposure. The thermal light sum released by IR illumination in the temperature region 90-150 K has a maximum at ≈108 K. The nature of this maximum is connected with the complex centers [Pb3+ + (WO3-F-)]. Optical and thermal degradation of these centers leads to the appearance of emission in the green region of the localized exciton spectrum. © 2010 Springer Science+Business Media, Inc.