Investigation on the Gamma-Rays Induced Radiation Damage Effect of LaBr₃:Ce and CeBr₃ Crystals

This work investigates gamma-rays induced radiation damage effect in LaBr3:Ce and CeBr3 crystals. Optical and scintillation properties of these crystals were characterized before and after irradiation up to $2\times 10^{6}$ rad. The recovery of radiation damage was observed in both crystals. After the crystals were irradiated at various dose rates, it was confirmed that the radiation damage saturation cannot be attributed to the dose rate dependent effect. After the irradiation up to $2\times 10^{6}$ rad, the loss of emission-weighted longitudinal transmittance (EWLT) values is approximately 4.7% for LaBr3:Ce and 6.0% for CeBr3. Meanwhile, the light yield (LY) loss of LaBr3:Ce and CeBr3 crystals is approximately 12.3% and 11.6%, respectively. The excellent correlation between EWLT loss and LY loss indicates that the LY degradation in both crystals can be mainly attributed to the loss of transmittance. The deterioration of energy resolution (ER) after 2-Mrad irradiation ranges from 5.1% to 6.7% for LaBr3:Ce and from 8.7% to 9.5% for CeBr3. The decay time is not affected by radiation damage. Compared with other scintillation crystals, LaBr3:Ce and CeBr3 crystals are radiation hard. These findings provide important insights into the behavior of these materials working in severe radiation environments, which is essential for their applications and production.