Crystallization processes control on growing large dimension crystals out of the melt

摘要

For automated pulling of large scintillation Nal(Tl) and Csl(Tl) crystals from melt on a seed a method of melt replenishment by raw material is used. Melt replenishment allows simplifying significantly the algorithm of controlling the crystallization process and quality of the grown crystals since it presumes a possibility of heat- and mass transfer stabilization at the crystallization front. However, in this case also it is impossible to avoid completely the destabilizing manifestations of mass transfer processes one of which is the mass transfer of a volatile impurity component from the melt to the vapor phase. At a corresponding approach these factors can be not only taken into account but also used for the control of impurity composition of the obtained crystals and crystallization process as a whole.