Author(s)

B.G. Zaslavsky, O.D. Kolotiy, LI. Kisyl, V.S. Suzdal, V.V. Lyakhov

Abstract

On some factors having an effect on heat exchange and stability of the process of automated pulling from melt of alkali halide crystals B.G.Zaslavsky, O.D.Kolotiy, LI.Kisyl, V.S.Suzdal, V.V.Lyakhov Institute for Single Crystals, Ukraine Abstract Isotherms in CsI(Tl) crystals were calculated for the case of automated pulling of the latter from melt in cylindrical and conical crucibles. For the conical crucible the crystallization isotherm has a more convex form towards the melt. This is explained by higher temperature gradients and intensive heat removal from the lower part of the growing crystal, this part being very close to the crystallization front. The conical crucible promotes increase of thermal stability of the pulling process. The calculation results were confirmed experimentally. Application of the conical crucible allowed to automate the stage of radial growth and to increase the pulling rate for large crystals to 5.5 mm/h even at a replenishment with fine cr

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