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
李浩炫 1徐彬 2冯朋磊 1向乙鑫 1卢位 1王磊 1王艳 2唐辉2
作者信息
- 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
- 折叠
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 1h,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/m3,其塑闪探测器的探测效率为 36%,MDC为 7.93 Bq/m3,均显著低于 38.50 Bq/m3.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.
Abstract
In order to achieve rapid and accurate measurement of Iodine-131 without enrichment,a combined method of γ and β for Iodine-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.NaI 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 γ omnipotent peak count and β count obtained by the detection system and Iodine-131 concentration.The system can first recognize Iodine-131 by obtaining γ spectrum and analyzing Iodine-131 characteristic peaks.The linear relationship between γ 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 NaI detector is 1.7%,its MDC can reach 19.59 Bq/m3,its plastic flash detector is 36%,and its MDC is 7.93 Bq/m3,both of which are significantly lower than 38.50 Bq/m3.The relative error of Iodine-131 concentration is less than 0.6%based on the combined formula of γ omnipotent peak count and β count.The proposed detection system makes full use of the advantages of high β-ray detection efficiency and strong recognition ability of γ-spectrum energy.The rapid and accurate measurement of Iodine-131 concentration can be achieved by means of γ-spectrum omnipotent peak counting and β-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Key words
Monte Carlo simulation/Iodine-131/full-energy peak count/beta measurement/minimum detectable concentration引用本文复制引用
基金项目
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)
出版年
2024
NETL
NSTL
万方数据