Effect of AuBr3 additive on the scintillation properties of BaBr2:Eu and Cs2LiLaBr6:Ce

Abstract

Following the observation of large increases in light output of BaBrCl:Eu single crystals using AuBr₃ as an additive in the melt, the impact of this process on the scintillation properties of other Br-based scintillating materials is investigated in an attempt to assess its broader use. Results for Cs₂LiLaBr₆:Ce and BaBr₂:Eu single crystals with various Ce and Eu concentrations are presented. The results indicate that such an additive has very different effects in the two investigated materials. Although AuBr₃ is not incorporated in the two crystalline matrices, it increases remarkably, by up to a factor 2, the light yield of BaBr₂:Eu in a similar manner to that observed for BaBrCl:Eu, but is at best ineffective in the case of Cs₂LiLaBr₆:Ce. The improvements detected in the case of BaBr₂:Eu are related to a substantial reduction in the long lived scintillation decay tails as well as in the thermally stimulated luminescence amplitude with respect to the crystal grown without AuBr₃ in the melt. These improvements are, however, associated with a reduction in the energy resolution of these crystals related to a worse energy response non-proportionality. In the case of Cs₂LiLaBr₆:Ce, no clear improvements in either the light yield or the scintillation decay time are visible in the case of low Ce content, while a reduction of light yield upon AuBr₃ addition caused by luminescence quenching phenomena is observed for high Ce concentration.