Production of a calcium fluoride single crystal comprises contacting a calcium fluoride charge with a seed crystal, heating to a temperature sufficient to form a melt, pulling a crystal through a temperature gradient zone, tempering

摘要

Production of orientated calcium fluoride single crystal comprises contacting calcium fluoride charge with seed crystal having specific crystallographic orientation, heating charge in first heating zone to form melt, pulling calcium fluoride crystal on seed crystal by gradually moving melt and seed crystal through temperature gradient zone, tempering pulled crystal in second temperature zone. Growth corresponds with seed orientation. Production of an orientated calcium fluoride single crystal comprises contacting a calcium fluoride charge with a seed crystal having a specific crystallographic orientation, heating the calcium fluoride charge in a first heating zone to a temperature which is sufficient to form a melt, pulling a calcium fluoride crystal on the seed crystal by gradually moving the melt and the seed crystal through a temperature gradient zone having an axial temperature gradient in the region of 2-8degreesC/cm, tempering the pulled crystal in a second temperature zone. The growing direction of the calcium fluoride crystal corresponds with the crystallographic orientation of the seed crystal. The first zone has a higher temperature than the second zone and the temperature gradient lies between the two zones. An Independent claim is also included for a calcium fluoride crystal produced by the above process.