GAGG∶Ce闪烁晶体的缺陷研究

Study on the Defects in GAGG:Ce Scintillation Crystal

通过提拉法生长了掺铈钆镓铝石榴子石结构闪烁晶体(简称GAGG∶Ce),采用扫描电镜、金相显微镜、能谱仪等手段观察和分析了晶体中容易出现的枝晶、位错、偏析、裂纹等缺陷。提出了产生缺陷的主要原因有引晶过程中的热冲击、籽晶位错的引入、提拉旋转速度以及降温工艺等因素产生的内应力。探讨了降低或控制GAGG∶Ce闪烁晶体中缺陷出现的方法。

GAGG:Ce single crystal was grown by Cz method.The dendrites,dislocations,segregation and crack defects in crystal have been observed and analyzed with SEM and metallurgical microscope and energy spectrometer and so on,which indicates that the defects are resulted from the thermal shock during the seeding process and the derivation andextension of seed dislocations and the stresses caused from the pulling speed and the cooling process.Finally,Based on these analyses,the measures to reduce or to control the generation of the defects in GAGG:Ce crystals were presented.