国产高Z闪烁晶体的辐照损伤研究

STUDY ON RADIATION DAMAGE OF CHINESE-MADE HIGH-Z SCINTILLATION CRYSTALS

在总强度为105~Ci的^(60)Co γ射线辐照装置上开展了国产高Z闪烁晶体的辐照损伤研究.在5×10~3-7.5×10~5rad剂量范围内测量了小尺寸BGO晶体样品的辐照损伤效应,观察到损伤随剂量增加逐渐趋于饱和的现象;辐照损伤的自然恢复过程可用三组时间常数表征的指数函数描述.在5×10~5rad剂量下,考察了BaF_2,CsI(Tl)以及ZnWO_4晶体小尺寸样品的辐照损伤效应.发现了BaF_2的严重损伤情况,初步分析原因可能是晶体中某些微量杂质的存在.

Radiation damage effects of several Chinese-made high-Z scintillation crystals have been studied on a ^(60)Co irradiation unit of 100 KCi. Results on small size BGO crystals irradiated by ^(60)Co γ rays with various doses from 5×10~3 to 7.5×10~5 rad are presented. The decrease in scintillation light output depends non-linearly on the dose applied and saturation effects above 5×10~4 rad have been observed. The spontaneous recovery of the light output can be described by the sum of at kast three exponential functions. The radiation damage effects of small size BaF_2, CsI(TI) and ZnWO_4 crystals at 5×10~5 rad were also investigated. Serious damage to BaF_2 has been found. Preliminary analyses indicate that this may be attributed to the inclusion of certain critical elements in the crystal. CsI(Tl) after irradiation does not exhibit strong afterglow or noticeable coloration as were reported in the literature.