基于数值积分法的无源效率刻度方案研究  

Study on Sourceless Efficiency Calibration Scheme Based on Numerical Integral Method

作　　者：熊超 袁新宇 王欣 吴和喜[1] XIONG Chao;YUAN Xinyu;WANG Xin;WU Hexi(Engineering Research Center of Nuclear Technology Application(East China Institute of Technology),Ministry of Education,Nanchang 330013,China;Radiation Environment Supervision State of Jiangxi Province,Nanchang 330077,China)

机构地区：[1]东华理工大学核技术应用教育部工程研究中心,南昌330013 [2]江西省辐射环境监督站,南昌330077

出　　处：《核电子学与探测技术》2024年第1期146-152,共7页Nuclear Electronics & Detection Technology

基　　金：国家自然科学基金资助项目(No.12265003&12205044);江西省自然科学基金资助项目(No.20212BAB201005);核技术应用教育部工程研究中心开放基金项目(HJSYJB2021-13)。

摘　　要：无源效率刻度技术一直是核分析领域研究的热点,但现行无源效率刻度技术需依据指定探测器进行订制。基于伽马射线指数衰减规律推导了圆柱体探测器周边任意位置点源探测效率的数值积分公式。依据探测器与待测物几何结构的轴对称性和伽马场叠加原理,构建了实验室常用几何结构体源的探测效率计算方案。在笔记本电脑(CPU:i5-8250U@1.60 GHz;RAM:8.0 GB)上应用上述方法计算HPGe圆柱体探测器对马林杯水体和NaI圆柱体探测器对圆柱体土壤内多种能量特征伽马射线的探测效率,发现探测效率计算值与实验值之间相对偏差为-4.9%~3.9%,且计算时长最大为35.78秒,证实本方法能准确、快速地实现圆柱体探测器的无源效率刻度。且本文推荐方法在探测器尺寸变化的情况下仅需修改相应参数,具有很强的通用性。Sourceless efficiency calibration method(SECM)is a hotspot for researchers in the field of nuclide analysis.Massive data within existing SECM need to be recalculated while the detector changes.In this paper,numerical integral formula of detection efficiency,for a point source at anywhere outside a cylinder detector,is derived based on exponential decay law of gamma ray.According to gamma field linear superposition principle,the calculation scheme of detection efficiency,for a frequently used volume source in the lab,is analyzed in detail.However,the computation is simplified based on the axial symmetry of cylinder detector and volume source.When gamma rays with different energies are emitted from a water-flled Marinelli beaker to a HPGe detector or from a soil-filled cylinder to a Nal detector,calculation scheme is compiled into code on a notebook computer to calculate detection efficiencies.And central processing unit and random-access memory of the notebook computer is i5-8250U@1.60 GHz and 8.0 GB.Through experiments and calculations,it is found that the relative deviation between their two efficiency values at many energies is from-4.9%to 3.9%.And the maximal computing time for all energies gamma ray is 35.78 seconds.The above experiment sufficiently demonstrated that the proposal method in this paper can calculate accurately and quickly the efficiency value for a cylinder detector.Meanwhile,this method has strong universality only because it only needs to modify the corresponding parameters when the detector size changes.

关 键 词：无源效率刻度 圆柱体探测器 数值积分法 

分 类 号：TL817.2[核科学技术—核技术及应用]