Zuchtung von orientierten lithiumflourid-einkristallen aus der dampfphase
A high vacuum oven was constructed to grow LiF single crystals from the vapor phase by the vertical pulling method. Using a special crucible top it is possible to grow oriented single crystals of 23 mm diameter and 70 mm length. At a temperature of about 150 \xb0C above the melting point the maximum pulling rate was found to be 8 mm/h. The purification effect of the sublimation was investigated for Na+-, K+-, Ca++-ions and it was found that the concentration of these impurities is of the order of 10-6, except for sodium for which the purification is much less effective.