Behaviors of metal-oxide impurities in CaF2 and BaF2 single-crystals grown with PbF2 scavenger by Stockbarger's method

The concentrations and distribution of trace amounts of metal impurities in CaF2 and BaF2 single-crystals grown from high purity CaF2 and BaF2 raw powders and 14 kinds of trace amounts of metal-oxide impurity additives (metal elements = Li, Na, Mg, Ca, Sr, Ba, Al, Cr, Fe, Ni, Cu, Y, La and Cc) under the addition of 3wt% PbF2 scavenger by the Stockbarger method were examined. In both CaF2 and BaF2 single-crystals, Li, Na, Cu and Pb were hardly detected. Transition metals of Cr, Fe and Ni hardly remained in the CaF2 single-crystals, while these metals slightly remained in BaF2 single-crystals. Elements of Mg, Ca, Sr, Ba and Al almost remained and, at the same time, Mg and Ba segregated in the CaF2 crystals and Mg, Ca, Sr and Al segregated in the BaF2 crystals. Rare earth metal elements of Y, La and Ce almost remained in both CaF2 and BaF2 crystals in spite of the addition of PbF2 scavenger. (C) 2003 Elsevier B.V. All rights reserved.