Scintillation efficiency of binary Li2O-2SiO2 glass doped with Ce3+ and Tb3+ ions

Photo- and radioluminescent properties of lithium silicate glasses doped with Ce3+and Tb3+ions were evaluated. Glasses doped with Ce3+ ions exhibit a shift of radioluminescence to photo-luminescence band. This effect was explained by a distribution of the crystal field strength in the activator sites, what results in the competition between different types of Ce3+ ions in absorbing excitation energy from the matrix and limits a light yield of the Ce3+ doped glass. We also investigated the possibility to use Tb3+ ion instead of Ce3+ as an alternative activator for a glass doping. Spin-orbit interaction plays a major role in the formation of electronic terms in Tb3+, where as an effect of the crystal field is small enough to form a distribution of emitting centers. Tb3+-doped samples demonstrate light yields up to 31000 ph/MeV with the concentration quenching starting at the levels of 10 at %. We also studied the effect of luminescence sensitization of Tb3+ ions by Ce3+ in the glasses co-doped with Ce3+ and Tb3+.