Effects of Calcium Codoping on Charge Traps in LSO:Ce Crystals

Experimental studies of Lu₂SiO₅:Ce (LSO:Ce) crystals codoped with various concentrations of Ca (0, 0.1, 0.2, 0.3, and 0.4 at% in the melt) are presented. The scintillation and optical properties including photoluminescence decay, emission, excitation, absorption, afterglow and thermoluminescence properties are investigated as a function of Ca concentration. Experimental data show Ca codoping significantly reduces the trapped charge population in the crystal matrix. Hence, the scintillation decay time of LSO:Ce is shortened and the afterglow is suppressed. Thermoluminescence studies show a strong correlation between the integrated thermoluminescence intensity and the Ca concentration.