关键词: 溴化铈, 闪烁晶体, Sr²⁺掺杂, 坩埚下降法, 晶体生长, 闪烁性能, 能量分辨率

Abstract: 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 ϕ25.4 mm×25.4 mm is obtained and the energy resolution is 3.92%@662 keV.

Key words: cerium bromide, scintillation crystal, Sr²⁺ doping, vertical Bridgman method, crystal growth, scintillation property, energy resolution