掺Sr2+溴化铈晶体的生长与闪烁性能研究

采用坩埚下降法生长了直径为25.4 mm的纯溴化铈晶体和0.1%、0.2%和0.5%(摩尔分数)Sr²⁺掺杂的溴化铈晶体。将所生长晶体加工成直径25.4 mm、厚度10 mm的坯件,并进行紫外和X射线激发荧光光谱、¹³⁷Cs源激发多道能谱等测试。结果表明:Sr²⁺掺杂会导致晶体X射线激发下的发射光谱出现轻微红移,而随着Sr²⁺掺杂量的增加,晶体的能量分辨率依次提高,光输出依次降低;当Sr²⁺掺杂量为0.5%时,溴化铈晶体的能量分辨率最高,达3.83%@662 keV,但过高含量的Sr²⁺掺杂会造成晶体生长困难。综合考虑晶体性能和生长情况,Sr²⁺掺杂量为0.2%时较为适宜,所获得的?25.4 mm×25.4 mm CeBr₃∶0.2%Sr晶体封装件的能量分辨率为3.92%@662 keV。

Growth and Scintillation Properties of Sr2+ Doped CeBr3 Crystal

25.4 mm diameter crystals of CeBr₃ and three analogues doped with 0.1%, 0.2% and 0.5% of Sr²⁺in molar ratio were grown by the vertical Bridgman method. The grown crystals were processed into 25.4 mm diameter wafer with a thickness of 10 mm and characterized by fluorescence spectra excited by UV light and X-ray as well as multi-channel analysis with ¹³⁷Cs source. Results show that the emission bands of the crystals under X-ray excitation are slightly red-shifted by Sr²⁺ doping, and with the increase of Sr²⁺ doping content, the energy resolution of the crystals are successively improved, while the light yield are gradually reduced. The CeBr₃ crystal doped with 0.5%Sr²⁺ exhibits the best energy resolution of 3.83%@662 keV. However, high Sr²⁺doping also causes difficulty in crystal growth. A doping content of 0.2% is considered appropriate with regards to both scintillation property and crystal growth availability. An encapsulated CeBr₃∶0.2%Sr crystal with dimension of ?25.4 mm×25.4 mm is obtained and the energy resolution is 3.92%@662 keV.