N.N.Smirnov, V.I.Goriletsky, S.K.Bondarenko
Received October 30, 1999
For automated pulling of large scintillation NaI(Tl)
and CsI(Tl) crystals from melt on a seed a method of melt
replenishment by raw material is used [1]. 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.