硅酸镥闪烁晶体的生长与缺陷研究

Growth and Study on Defects of LSO:Ce Scintillation Crystal

本文采用提拉法生长出了硅酸镥闪烁晶体 ,讨论了晶体生长中遇到的问题 ,所生长的硅酸镥晶体有开裂、解理、多晶、回熔现象等宏观生长缺陷和包裹物、位错等微观缺陷。开裂是由热应力和晶体解理两种因素引起的 ,其中热应力是导致开裂的主要因素 ,优化生长工艺条件可完全避免开裂。晶体中存在两种包裹物 ,成份分别为氧化镥和坩埚材料铱 ,氧化镥很可能是未参加反应的原料 。

Li2SiO5:Ce(LSO) scintillation crystal grown by Czochralski method is reported and growing difficulties are discussed. Then macro-defects including crack, cleavage, polycrystal and remelting and micro-defects including inclusions and dislocation in LSO crystal were found, and the origin of defects was simply analyzed. The cracking of crystal is caused by both thermal stress and cleavage. The thermal stress is considered to be the main factor. By setting the preferred growth condition, LSO crystal free from cracks was successfully grown. There were two types of inclusions, whose components are respectively Lu2O3 and Ir. The inclusions of Ir come from the crucible and inclusions of Lu2O3 maybe come from the raw material Lu2O3 not reacting. It also probably resulted from SiO2.