摘要
溴化镧(LaBr3)闪烁体是一种新型的无机闪烁体材料,可用于便携式γ辐射探测器的制备,应用于辐射剂量测量、放射性核素识别以及235U富集度测量等.本文通过系统测试并对LaBr3探测器的性能参数进行验证,结果表明:LaBr3探测器的最佳工作电压为570 V.经3个点位刻度后,不同放射源能峰的偏差均小于0.69%.连续40 d的本底测量中,37.25 keV能峰中心道几乎没有漂移,1467.99 keV能峰中心道偏差小于1.78%.37.25 keV与1467.99 keV的计数率偏差分别小于11.89%和7.75%.连续4 d(15次)天然铀测量中,185.72 keV的道数漂移偏差小于0.47%,计数率偏差小于9.01%.当死时间小于3.98%时,可清晰辨别235U的4个特征能峰.因此,当测量235U 185.72 keV的能峰时,需控制死时间小于3.98%.单一放射源在0.10~30µSv/h剂量率下,核素识别时间在1~120 s之间.混合放射源(源距探头50 cm)识别时间因活度的不同而略有差异.500~650 V电压区间内经能量自刻度后,铀标准源185.715 keV峰能量最大偏差为3.20%.通过拟合得到探测效率函数为f(E)=-33.76+15.34lnE-2.61ln2 E+0.14ln3 E,模拟和实测探测效率误差大多在10%以内.该验证方法简便、通用,可为科研工作者在进行同类探测器的性能测试时提供参考,同时也为后续开展探测器的结构设计、优化等提供便利.
Lanthanum bromide(LaBr3)scintillation material is a novel inorganic scintillation material that can be used in portable gamma radiation detectors for radiation dose measurement,radionuclide identification,and 235U enrichment measurement.The performance parameters of the LaBr3 detector were systematically tested.The results indicated that the optimal operating voltage was determined to be 570 V.After three-point calibration of the detector,the energy peak deviation for different radiation sources was less than 0.69%.Continuous background measurements were conducted on the detector for 40 d,and there was almost no drift in the peak channel of the 37.25 keV peak,while a slight drift was observed in the peak channel of the 1467.99 keV peak,with a deviation of less than 1.78%.The counting rate deviations for 37.25 keV and 1467.99 keV were less than 11.89%and 7.75%,respectively.Consecutive measurements of natural uranium were performed 15 d,the peak channel drift deviation was less than 0.47%,and the peak counting rate deviation at 185.72 keV was less than 9.01%.When the dead time was less than 3.98%,four distinct energy peaks of 235U could be observed.Therefore,the dead time should be controlled below 3.98%when measuring the 185.72 keV energy peak of 235U.For a single radioactive source with a dose rate ranging from 0.1 to 30µSv/h,the nuclide identification time varied from 1~120 s.For mixed radioactive sources,the nuclide identification time of the LaBr3 detector varied slightly with activity when the source-probe distance was 50 cm.Energy self-calibration was performed at voltages ranging from 500 to 650 V,followed by measurements of a uranium standard source.The energy deviation of the 185.72 keV was recorded,with a maximum deviation of 3.20%.By measuring different radiation sources with the LaBr3 detector,a detection efficiency fitting curve was obtained,and the fitting function was determined as:f(E)=-33.76+15.34lnE-2.61ln2 E+0.14ln3 E.Detector characterization showed that the deviations between simulated and measured detection efficiencies were mostly within 10%.The method is simple and universal,which can provide a reference for researchers conducting performance tests of similar detectors,and also facilitate the subsequent structural design and optimization of detectors.
作者
李多宏
牛顺利
陈金铸
陈宇亭
刘崎
纪建臣
骆无瑕
蒋虹
黎春
LI Duohong;NIU Shunli;CHEN Jinzhu;CHEN Yuting;LIU Qi;JI Jianchen;LUO Wuxia;JIANG Hong;LI Chun(State Nuclear Security Technology Center,Beijing 102401,China;China Nuclear Security Technology Co.Ltd.,Beijing 102206,China;School of Nuclear Science and Engineering,North China Electric Power University,Beijing 102206,China)
出处
《分析测试技术与仪器》
2025年第6期370-378,共9页
Analysis and Testing Technology and Instruments
基金
国际原子能机构IAEA CRP项目“基于LaBr3143-1001 keV相对效率法确定铀富集度方法研究(编号:CRPJ02020)”[IAEA CRP J02020 on"Study on the Method for Determining Uranium Enrichment Based on LaBr3143-1001 keV Relative Efficiency Method"]。
关键词
溴化镧探测器
性能
探测效率
自刻度
表征
lanthanum bromide detector
performance
detection efficiency
self calibration
characterization
