闪烁晶体的生长与宏观缺陷研究

用提拉法生长了Lu2Si2O7：Ce晶体，讨论了晶体生长过程中的几个问题；（1）熔体挥发；（2）晶体开裂；（3）层状包裹．生长过程中LPS和SiO2均存在挥发，其中后者占主导；LPS挥发不会造成组分偏析，因此对生长过程没有负面的影响．接种温度偏低导致晶体出现多晶化和晶体中较大的热应力是促使开裂发生的主要原因．层状包裹现象的出现主要是由于该晶体的结晶温度范围狭窄，熔体容易出现组分过冷，以及生长设备的温控系统精度不高等造成的．

Growth and Macro-defects Study of Lu2Si2O7:Ce Scintillation Crystal

Cerium-doped lutetium pyrosilicate (LPS:Ce) crystal was grown by using the Czochralski method. A series of problems during growth, such as volatilization of the melt, crack and sandwich inclusions, were discussed. Results show that the components of LPS and SiO2 volatilize during growth, and the latter is dominant. As volatilization of LPS will not lead to components segregation, there is not a negative affection on the growth process. Poly-crystal caused by the lower seeding temperature and the biggish thermal stress in the crystal are the main reasons for crystal crack. Sandwich inclusions phenomenon is mainly related to three factors, the first is the narrow crystallization temperature of LPS:Ce crystal, the second is the constitutional supercooling appearing in the melt, and the third is the poor precision of the temperature-monitoring systems of the growth equipment.