Effect of ^-Doping on the Temperature Dependence of : Photoluminescence

The temperature dependence of the photoluminescence properties of {\rm Gd}_{2}{\rm SiO}_{5}:{\rm Ce},{\rm Ca} crystals was found to be significantly affected by Ca codoping and shows that presence of additional energy levels in these crystals provides nonradiative energy transfer. The excitation and emission bands also broaden with codoping due to presence of these additional energy levels. Therefore Ca codoping in {\rm Gd}_{2}{\rm SiO}_{5} crystals decreases the scintillation decay very strongly and has a strong adverse affect on scintillation light yield, different from the effect in other members of the oxyorthosilicate family such as {\rm Lu}_{2}{\rm SiO}_{5} and {\rm Y}_{2}{\rm SiO}_{5} .