Preparation of anhydrous lanthanum bromide for scintillation crystal growth

This paper reported an efficient and economical method for preparation of anhydrous LaBr3 for scintillation crystal growth. High purity anhydrous LaBr3 powders in large quantities were successfully obtained by stepped dehydration of LaBr3·7H2O using NH4Br as additive. Experiments revealed that adding proper amount of NH4Br could effectively restrain the hydrolysis of LaBr3 during dehydration and thus decreased the yield of deleterious impurity of LaOBr. Optimum preparation conditions, including the amount of NH4Br in use, the dehydration temperature and atmosphere, were investigated by DTA/TG and water/oxygen analysis. The Raman characterization of the as-prepared anhydrous LaBr3 was also presented.