Europium-doped barium halide scintillators for x-ray and γ-ray detections

Single crystals of Ce-activated BaCl2, BaBr2, and BaI2 were investigated under x-ray and γ-ray excitation. The Ce3+-related x-ray excited luminescence in BaBr2 shifts significantly to longer wavelengths upon increasing the doping level from 0.1% to 1%. In Ce-activated BaCl2 only a slight shift can be observed. BaI2 does not show any Ce3+-related emission. Scintillation decay time measurements show that the decay in BaBr2 is delayed due to migration processes. Additional K doping has a large influence on the scintillation decay time properties but not on the overall efficiency.