摘要
目的研发适用于便携式HPGeγ能谱仪的马林杯大体积样品盒,通过鲜样测量给出该样品盒不同测量时间的探测限,为应对核与辐射突发事件监测提供参考。方法根据GB/T 16145—2022探测限计算公式,利用无源效率刻度软件Angle,使用便携式HPGeγ能谱仪针对131I和137Cs的测量,优化出大体积样品盒;使用马林杯大体积样品盒鲜样装样测量马哈鱼样品,测量活时间分别为2、4、6、8、10、19、22、24 h,分析测量时间与探测限关系。结果在样品盒相同的15 cm半径和约10 L体积条件下,使用马林杯大体积样品盒比圆柱形大体积样品盒模拟探测效率能够提升将近30%~46%,探测限更低。应用其测量马哈鱼鲜样所得探测限随测量时间延长而降低,并给出了鲜样测量核污染水中核素的不同测量时间可达的探测限参考。结论结合探测限优化研发的马林杯大体积样品盒,对应急情况下现场γ核素监测提供了定量分析的几何形状,不同测量时间该样品盒鲜样测量结果表明,8~10 h的测量时间探测限的下降与测量时间代价分析最优。
Objective To develop a large-volume sample cassette in the shape of a formalin cup suitable for portable HPGeγspectrometer,to determine the detection limits of the cassette at different detection times through fresh sample measurements,and to provide a reference for responding to and monitoring of nuclear and radiation emergencies.Methods According to the formula for calculation of detection limit described in the GB/T 16145—2022,131I and 137Cs were measured using the sourceless efficiency calibration software Angle and the portable HPGeγspectrometer for the optimization of the large-volume sample cassette.Fresh salmon samples were measured using a formalin cup-shaped large-volume sample cassette.The detection times were 2,4,6,8,10,19,19,22,and 24 hours.The relationship between detection time and detection limit was assessed.Results Using sample cassettes with 15 cm radius and 10 L volume,the simulated detection efficiency of the formalin cup-shaped large-volume sample cassette was 30%-46%higher and the detection limit was lower as compared with the cake-shaped large-volume sample cassette.The detection limit obtained by measuring fresh salmon samples decreased with the extension of the detection time.These results provided a reference for the detection limits of measuring fresh samples for nuclides of concern in nuclear contaminated water with different detection times.Conclusion The formalin cup-shaped large-volume sample cassette developed by combining the optimization of detection limit provides a geometry for quantitative analysis in on-site monitoring ofγnuclides in the case of emergencies.Measurement of fresh samples using the cassette with different detection times showed that 8-10 hours of detection was optimal in balancing the detection limit and the detection time.
作者
孔令南
杨宝路
张京
周强
KONG Lingnan;YANG Baolu;ZHANG Jing;ZHOU Qiang(Key Laboratory of Radiological Protection and Nuclear Emergency,China CDC,National Institute for Radiological Protection,Chinese Center for Disease Control and Prevention,Beijing 100088 China)
出处
《中国辐射卫生》
2024年第4期358-363,369,共7页
Chinese Journal of Radiological Health
基金
首都卫生发展科研专项(首发2022-2G-3019)。
关键词
探测限
大体积样品盒
无源效率刻度
检测时间
Detection limit
Large-volume sample cassette
Sourceless efficiency calibration
Detection time
