Gamma-radiation-induced absorption in doubly doped PbWO4:Mo,Y crystals

The set of Mo and (Mo,Y) doped PbWO4 scintillating crystals was irradiated 30 min by a homogeneous gamma-radiation field, produced in the irradiation of tungsten target by 21 MeV electron beam from the microtrone accelerator. The induced absorption spectra were measured on-line, i.e. during the irradiation and after switching-off the machine with a sampling rate of 10 s for the dose rates of about 0.17 Gy/min. The results show a clear effect of the doped ions in PWO crystals on the spectra and kinetics of both colour centres formation and recovery processes. The induced absorption build-up and recovery time dependences at fixed wavelength are approximated by a simple model and quantitative parameters are extracted and discussed.