Recombination Processes in $PbWO_{4}:Tb^{3+}$ Crystals

In the paper the results of investigations of X-ray excitation spectra, thermostimulated luminescence and the influence of light illumination on the thermoluminescence glow curves of pure and Tb-doped $PbWO_{4}$ crystals are presented. It is suggested that the $F^{-}$-centres are formed in $PbWO_{4}$ crystals at filling oxygen vacancies near $Pb^{3+}$ ions to three electrons under X-ray irradiation at 90 K. The nature of 108 K thermostimulated luminescence peak is connected with the $[(WO_{3} + F^{-})-Pb^{3+}]$ associations. It was established that thermal or optical destruction of this peak leads to appearance of the radiative transitions of excitons localized near the $[(WO_{3} + F)-Pb^{2+}]$ complex centres.