Lu_2SiO_5∶Ce晶体生长中存在的主要问题  

MAIN PROBLEMS IN THE GROWTH OF Lu_2SiO_5∶Ce SCINTILLATION CRYSTALS

作　　者：秦来顺[1] 任国浩[1] 李焕英[1] 陆晟[1] 裴钰[1] 

机构地区：[1]中国科学院上海硅酸盐研究所,上海201800

出　　处：《硅酸盐学报》2004年第11期1361-1366,共6页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(50272072)资助项目。

摘　　要：用提拉法生长了40mm×60mm的Lu2SiO5∶Ce(LSO∶Ce)晶体,讨论了晶体生长中存在的3个主要问题:(1)偏组分;(2)铱金坩埚的被熔蚀和挥发;(3)LSO晶体中的包裹体。生长LSO晶体过程中SiO2容易挥发,在籽晶夹和炉膛内结晶成方石英相,造成组分偏析;在高温下铱金坩埚会被熔蚀,铱则会直接挥发,熔体中出现铱金碎片,严重影响接种、缩颈工艺等,所生长晶体表面也会粘附很多铱金颗粒,采用双抽双充气的办法减弱了铱金的挥发,基本上克服了铱金的干扰;LSO晶体中出现的包裹物主要是Lu2O3,也有极少量的气孔,Lu2O3主要是由于固相反应不彻底和SiO2挥发引起的。LSO:Ce crystals with a dimension of φ40 mm × 60 mm were grown by Czochralski method. Three main problems during growth, such as component segregation, corrosion and volatilization of the iridium crucible and inclusions in LSO:Ce crystal, were discussed. During the growth of LSO crystals, the component of SiO2 was volatilized easily and then crystallized as cristobalite on seed clamp and wall of furnace. Iridium crucible was easy to be corroded and volatile at the high temperature, so that there were many pieces of iridium in the melt. This would have a heavy impact on inoculation, necking, etc. Accordingly the grown crystal was coated with lots of iridium particles. By use of double extraction and filling of gas the problem was basically overcome and there was nearly no iridium particle in the melt and on the surface of crystals. The dominant inclusion appearing in LSO crystal is Lu2O3, and there is also a little void. The inclusion of Lu2O3 may be caused by uncompleted solid state reaction and volatilization of SiO2.

关 键 词：硅酸镥晶体 闪烁晶体 提拉法 组分偏析 铱坩埚 

分 类 号：O782.5[理学—晶体学]