IN-SITU MEASUREMENT OF INTERFACE SUPERCOOLING DURING GROWTH OF BI4GE3O12 SINGLE-CRYSTALS FROM MELT

The experimental technique and equipment for measuring the interface s upercooling during growth of dielectric single crystals from a melt ar e described. The supercooling is measured by a pyrometer from the inte nsity of thermal radiation of the interface that is recorded through t he growing crystal. Bismuth germanate (Bi4Ge3O12) is chosen as an obje ct of investigation. Its properties are such that a signal recorded by a pyrometer is proportional to the interface temperature. The tests a nd method have shown that, for the selected experimental conditions, t he radiation from the single-crystal bulk and the reflection from samp le boundaries have no effect on the measured signal.