Synthesis of a Bismuth Germanium Oxide Source Material for Bi_4Ge_3O_(12) Crystal Growth

摘要

A technique has been developed for the preparation of a modified source material for the crystal growth of bismuth orthogermanate, Bi_4Ge_3O_(12) (BGO). It includes dispersion of molten bismuth through mixing with germanium oxide (GeO_2) powder in a rotating reactor, followed by oxidation with oxygen. The source material thus prepared contains, in addition to bismuth and germanium oxides, considerable proportions of germanates (Bi_2GeO_5, Bi_4Ge_3O_(12), and Bi_(12)GeO_(20)), which improve the reactivity of the components of the source material during homogenization before the crystal growth process. After sintering at 880℃, the density of the modified source material (3.9 g/cm~3) is a factor of 1.5 higher than that of a source material prepared from Bi_2O_3 and GeO_2 powders. BGO crystals grown using the synthesized source material possess good scintillation characteristics.