医用放射性废液取样容器尺寸的最优化研究  

Optimization study on the size of medical radioactive waste liquid sampling container

作　　者：陆小军[1] 刘佳煜 胡崇庆 韩刚 宋家斑 何林锋[1] 畅金学 LU Xiaojun;LIU Jiayu;HU Chongqing;HAN Gang;SONG Jiaban;HE Linfeng;CHANG Jinxue(Shanghai Institute of Measurement and Testing Technology,Shanghai 201203,China)

机构地区：[1]上海市计量测试技术研究院,上海201203

出　　处：《核技术》2024年第7期41-47,共7页Nuclear Techniques

基　　金：上海市公共卫生重点学科项目(No.GWⅥ-11.1-40);上海市放射性安全检测及污染控制专业技术服务平台研发专项(No.H00RK2319);上海市市场监督管理局科技项目(No.2022-07)资助。

摘　　要：医用放射性废液中核素放射性活度必须经监测满足相关标准后,该放射性废液方可排放,采用LaBr3(Ce)晶体探测医用放射性废液的核素活度,废液样品体积及其在探测器周围的分布情况直接影响探测效率,为此利用Geant4工具建立LaBr3(Ce)晶体探测模型,探索最优马林杯样品盒尺寸参数的变化规律,并在实验室利用?25.4 mm×25.4 mm的LaBr3(Ce)探测器和3D打印光敏树脂样品盒作验证实验。结果显示:单纯增加样品体积不能提高探测效率,随着样品体积增大,探测效率随样品盒环状部分深度方向的变化趋势趋于平缓。研究得到马林杯最优尺寸比例:环状部分深度(h2)和顶部半径(r)分别约为探测器晶体长度和空心腔直径的两倍,顶部半径(r)和样品盒高度(H)之比约为0.5。在最优化尺寸下,全能峰探测效率实验值与模拟结果一致,相对偏差优于2.5%。研究结果将为后续医用放射性废液监测装置在探测器选择、采样容器设计、加工及放射性废液监测量值溯源方法等方面提供重要的技术借鉴。[Background]With the development of nuclear medicine,the amount of medical radioactive waste increase rapidly.The radioactivity of nuclides in medical radioactive liquid waste must be monitored to meet the relevant standards before discharge of the radioactive liquid waste.The volume of the waste sample and its distribution around the detector have a direct impact on the detection efficiency.[Purpose]This study aims to explore the variation law of the size parameters of the optimal Marlin cup sample box and provide a basis for subsequent monitoring methods.[Methods]The LaBr3(Ce)crystal was applied to the detection of nuclide activity in medical radioactive waste liquid.Geant4 tool was employed to establish a LaBr3(Ce)crystal detection model.The changing rules of the optimal Marin cup sample box size parameters were explored using aØ25.4 mm×25.4 mm LaBr3(Ce)detector,and 3D printed photosensitive resin samples were used in the laboratory box for verification experiments.[Results]Experimental results show that simply increasing the sample volume cannot improve the detection efficiency,and the change trend of the detection efficiency in the depth direction of the annular part of the sample container tends to be flat with increase of the sample volume.The optimal size ratio of the Marinelli beaker is that the depth of the annular portion(h2)and the radius(r)are approximately two times the length of the detector crystal and the diameter of the hollow cavity,respectively,and the ratio of the radius(r)to the height of the sample container(H)is approximately 0.5.The experimental results of the full energy peak detection efficiency with optimized sample container size are consistent with the simulation results,and the relative deviation is better than 2.5%.[Conclusions]The results of the study provide an important technical reference for detector selection,sampling container design,and processing and traceability methods of medical radioactive liquid waste monitoring devices.

关 键 词：医用放射性废液 取样容器尺寸 最优化 Geant4模拟 LaBr3(Ce)探测器 

分 类 号：TL84[核科学技术—核技术及应用]