Precursors preparation for growth of low-background scintillation crystals

The precursors’ purity is one of the main factors when growing crystals with predetermined functional properties. Impurities composition greatly influence optical properties, radiation hardness and decay time of scintillation crystals and directly relates to crystal’s own radiation background. On an example of Bi4Ge3O12 (BGO) crystal growth dependence of optical and scintillating properties and radiation hardness from growth technique and the purity of initial bismuth oxide Bi2O3 was shown. In general the goal of obtaining crystals for rear events registration is an even more complex problem. At one hand one has to obtain crystals with the best scintillation properties, at another hand their own radiation background has to be extremely low, especially in a group of elements such as K. Besides that, due to a high cost of isotopically-enriched materials maximal utilization of compound during growth process and recuperation of residuals after growth and cutting with minimal material losses is strictly required.