塑料闪烁光纤阵列探测器研制及验证  

Development and Verification of Plastic Scintillation Fiber Array Detector

作　　者：马鹏[1] 孙宏清[1] 党云博[1] 宋志君[1] 张生栋[1] 舒复君[1] MA Peng;SUN Hongqing;DANG Yunbo;SONG Zhijun;ZHANG Shengdong;SHU Fujun(China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《原子能科学技术》2022年第9期1952-1957,共6页Atomic Energy Science and Technology

摘　　要：为解决污染土壤中^(90)Sr的快速、直接测定难题,研制了塑料闪烁光纤阵列探测器,通过塑料闪烁光纤空间排布设计、多路信号分析逻辑设定,实现从β、γ及宇宙射线信号中甄别出^(90)Sr-^(90)Y衰变的β射线信号,完成了土壤中^(90)Sr的直接测量。探测器本底计数率为1.98 s^(-1),^(90)Sr探测效率为1.4%,最小可探测活度为0.18 Bq/g(5 min),测量净计数率与参考土壤^(90)Sr比活度呈线性关系,拟合优度为0.999。测量了极低放污染土壤,通过添加定量的^(90)Sr再次测量方式对结果进行验证,测量值与参考值符合较好。塑料闪烁光纤阵列探测器测量速度快、准确度高,可用于核设施退役、环境普查等大规模土壤样品^(90)Sr快速、直接测定。^(90)Sr is one of the main nuclides in environmental radioactive pollution monitoring,the^(90)Sr specific activity in soil is an important data for environmental monitoring,and especially it needs be accurately measured when the specific activity is above 1 Bq/g.Usually,the^(90)Sr in soil is determined by radiochemical methods.^(90)Sr or daughter-nucleus^(90)Y in the soil is separated by radiochemical methods and then theβray is measured to calculate^(90)Sr in the soil.Because of the complex chemical process,it is difficult to quickly analyze the^(90)Sr of a large number of soil samples during the decommissioning of nuclear facilities.Measuring the^(90)Sr-^(90)Yβ-ray emitted from the soil surface or the secondary rays produced by the interaction with the soil medium,can realize the direct measurement of^(90)Sr in the soil.In order to solve the problem of rapid and direct determination of^(90)Sr in contaminated soil,a laminated plastic scintillation fiber array detector was developed.Through the design of the scintillation optical fiber space layout and the logic setting of multi-channel signal analysis,theβ-ray signal from^(90)Sr-^(90)Y decay can be distinguished.The effective detection area of the detector is 100 mm×200 mm,and the radiation signal is obtained by NIM standard electronic plug-in.The detection sensitive part consists of the first,second and third layers of 1 mm square plastic scintillation fiber array,10 mm PMMA absorber and the fourth layer of 1 mm square plastic scintillation fiber array(the first layer facing the tested soil).At the same time,when the first three layers of scintillation fiber produce fluorescence and the fourth layer does not produce fluorescence,it is recorded as a^(90)Y decay event.γ-rays pass through the detector,and the probability of fluorescence in the three-layer scintillation fiber is very low,that is,the detector is not sensitive toγ-rays and can measure the^(90)Sr in the soil in a strongγ-radiation environment.The detector background count rate is 1.98 s^(-1),th

关 键 词：闪烁光纤 阵列探测器 ^(90)Sr 土壤 

分 类 号：TL812[核科学技术—核技术及应用]