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采用剂量为 4Mrad的γ射线辐照Bridgman法生长的未掺杂和掺铋钨酸铅晶体 ,研究了辐照前后晶体的透射光谱、X射线激发发射光谱 (XSL)的变化 .利用正电子湮没寿命谱 (PAT)和X光电子能谱 (XPS)的实验手段 ,对钨酸铅晶体辐照前后的微观缺陷进行了研究 ,并对其抗辐照损伤性能及微观机理进行了初步探讨 .研究表明 ,铋掺杂使得晶体中的正电子捕获中心和低价氧浓度下降 ;辐照后 ,未掺杂晶体中正电子捕获中心浓度下降 ,低价氧浓度上升 ,掺铋晶体则出现了与之完全相反的情况 ,正电子捕获中心浓度上升 ,低价氧浓度下降 .提出掺铋钨酸铅晶体中铋的掺杂辐照前主要以Bi3+占据VPb的形式存在 ,辐照使变价元素铋发生Bi3+→Bi5+的变价行为 ,Bi5+可以替代W6+格位并使得晶体内部分 (WO4 ) 2 -根团形成 (BiO3+Vo) -.
The transmittance spectra and X-ray emission spectrum (XSL) of the crystals before and after irradiation were studied by irradiating Bridgman’s undoped and bismuth-doped lead tungstate crystals with a dose of 4Mrad. The positron annihilation lifetime (PAT) and X-ray photoelectron spectroscopy (XPS), the microscopic defects of lead tungstate crystals before and after irradiation were studied and their anti-radiation damage properties and microscopic mechanism were discussed. The bismuth doping led to the decrease of the positron capture center and the low oxygen concentration in the crystal. After irradiation, the concentration of the positron trapping center in the undoped crystal decreased and the oxygen concentration in the low-cost rose, while the bismuth-doped crystal appeared completely opposite , The concentration of positron capture center increased and the oxygen concentration of hypoxia decreased.It is proposed that before the doping of bismuth tungstate crystals, Bi3 + occupy VPb, and the bismuth is changed into Bi3 + → Bi5 + In the case of price change, Bi5 + can replace the W6 + lattice sites and cause the intramolecular (WO4) 2 - group to form (BiO3 + Vo) -.