医疗场所空气中碘-131在线探测系统模拟设计  

Simulation Design of Iodine-131 Online Detection System in the Air of Medical Place

作　　者：李浩炫 徐彬[2] 冯朋磊 向乙鑫 卢位 王磊[1] 王艳[2] 唐辉 LI Haoxuan;XU Bin;FENG Penglei;XIANG Yixin;LU Wei;WANG Lei;WANG Yan;TANG Hui(Chengdu University of Technology,Chengdu 610059,China;Sichuan management and monitoring center station of radioactive environment,Chengdu 611139,China)

机构地区：[1]成都理工大学,成都610059 [2]四川省辐射环境管理监测中心站,成都611139

出　　处：《核电子学与探测技术》2024年第1期69-76,共8页Nuclear Electronics & Detection Technology

基　　金：国家自然科学基金资助项目(41874121);四川省科技计划项目(2021JDRC0068);四川省科技计划项目(2021JDRC0107)。

摘　　要：为了实现无富集条件下对碘-131的快速精准测量,提出了针对医疗场所空气中碘-131的γ、β联合测量方法。通过Geant4建立探测系统模型,模拟研究探测系统对碘-131释放的β粒子和γ射线进行探测,其中NaI探测器和塑料闪烁体探测器分别实现对γ射线和β射线的测量。模拟计算表明,探测系统获取的γ全能峰计数、β计数与碘-131浓度之间存在线性关系。系统可首先通过获取γ能谱分析碘-131特征峰实现碘-131识别,利用γ射线全能峰计数与β射线计数之间的线性关系确定β射线贡献是否仅来自于碘-131,然后利用β射线的高探测效率进行快速测量。模拟计算探测系统测量1 h,其双3英寸NaI探测器的探测效率为1.7%,其MDC可达到19.59 Bq/m^(3),其塑闪探测器的探测效率为36%,MDC为7.93 Bq/m^(3),均显著低于38.50 Bq/m^(3)。基于γ全能峰计数和β计数的联合计算公式计算的碘-131的浓度,相对误差≤0.6%。提出的探测系统充分利用了β射线探测效率高和γ能谱能量识别能力强的优点,通过γ能谱全能峰计数和β计数测量可实现碘-131浓度的快速准确测量。In order to achieve rapid and accurate measurement of Iodine-131 without enrichment,a combined method of andβfor lodine-131 in the air of medical facilities was proposed.Geant4 was used to establish a detection system model to simulate the detection system to detect beta particles and gamma rays released by Iodine-131.Nal detector and plastic scintillation detector could measure gamma rays and beta rays respectively.The simulation results show that there is a linear relationship between the omnipotent peak count andβcount obtained by the detection system and Iodine-131 concentration.The system can first recognize lodine-131 by obtaining spectrum and analyzing Iodine-131 characteristic peaks.The linear relationship between ray universal peak count and beta ray count is used to determine whether the contribution of beta ray is only from Iodine-131.Then,the high detection efficiency of beta ray is used for rapid measurement.The detection efficiency of dual 3-inch Nal detector is 1.7%,its MDC can reach 19.59 Bq/m°,its plastic flash detector is 36%,and its MDC is 7.93 Bq/m^(3),both of which are significantly lower than 38.50 Bq/m^(3).The relative error of Iodine-131 concentration is less than 0.6%based on the combined formula of omnipotent peak count andβcount.The proposed detection system makes full use of the advantages of highβ-ray detection efficiency and strong recognition ability of-spectrum energy.The rapid and accurate measurement of Iodine-131 concentration can be achieved by means of-spectrum omnipotent peak counting andβ-counting measurement.

关 键 词：蒙特卡罗模拟 碘-131 全能峰计数 β测量 最小可探测活度 

分 类 号：R144[医药卫生—公共卫生与预防医学]