超大面积屏栅电离室的研制  

Development of Ultra-large Area Grid Ionization Chamber

作　　者：党云博[1] 丁有钱[1] 孙宏清[1] 马鹏[1] 黄昆 张生栋[1] DANG Yunbo;DING Youqian;SUN Hongqing;MA Peng;HUANG Kun;ZHANG Shengdong(.Department of Radiochemistry,China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院放射化学研究所,北京102413

出　　处：《原子能科学技术》2021年第5期945-953,共9页Atomic Energy Science and Technology

摘　　要：核设施退役过程中,需对超过1000 cm^(2)以上的大面积超铀核素平面板放射性进行准确定量,常用无损测量方法有效测量面积均较小,且探测限较高,不能满足快速分析大面积低活度样品的需求。屏栅电离室是一种用于低水平α放射性能谱测量的仪器,可满足以上分析需求,但受制于电极加工工艺,可测样品一般小于500 cm^(2)。为解决以上问题,研制了灵敏面积接近2000 cm^(2)的超大面积屏栅电离室,通过对工作气压和电压的调试优化,该电离室对~(241)Am电沉积源的能量分辨率为1.8%,最小可探测活度为10~(-2)Bq,对直径≤460 mm的平面样品2π角探测效率为97.7%。During the decommissioning of nuclear facility,it is necessary to accurately quantify the radioactivity of large-area transuranic nuclide planes over 1000 cm^(2).Common non-destructive measurement methods have small effective measurement area and high detection limit,which cannot meet the requirement of rapid analysis of large-area low-activity sample demand.The grid ionization chamber is an instrument used for low-level alpha radioactivity spectrum measurement,which can meet the analysis requirement of low-level sample.However,due to the electrode processing technology,the measurable sample is generally less than 500 cm^(2).To solve this problem,an ultra-large area grid ionization chamber with a sensitive area close to 2000 cm^(2)was developed.Through the adjustment and optimization of the pressure and voltage,the ultra-large area grid ionization chamber has a 1.8%energy resolution for the 241Am electrode position source,a minimum detectable activity of 10-2 Bq,and a 2πangle detection efficiency of 97.7%for a flat sample with a diameter less than 460 mm.

关 键 词：超铀核素 无损测量 屏栅电离室 

分 类 号：P204[天文地球—测绘科学与技术]