延迟符合法^(219)Rn测量研究  

Study of Measurement of ^(219)Rn via Delayed Coincidence Method

作　　者：黄德荣[1] 颜拥军[1] 周剑良[1] 丘寿康[1] 

机构地区：[1]南华大学核科学技术学院,湖南衡阳421001

出　　处：《南华大学学报（自然科学版）》2013年第1期16-21,共6页Journal of University of South China：Science and Technology

基　　金：国家自然科学基金资助项目(11175082)

摘　　要：介绍了延迟符合测量氡同位素的基本原理,并重新推导了关于219Rn的偶然符合修正公式.同时提出了通过实际测量比较的方法求存活因子和衰变因子的计算方案,避免了现有理论计算公式的误差.分别对222Rn、219Rn混合场和222Rn、220Rn、219Rn混合场下的219Rn源进行测量.实验结果显示,本底为7.5 cpm时,延迟符合实验系统能够分辨测量7～25 cpm的219Rn源,其测量结果与标准值偏差均在±8%以内.延迟符合法能够在氡混合场中分辨并测量出低水平219Rn.The principle of delayed coincidence counting technology to discriminate radon isotopes are introduced in this paper, and the calculation formulas of chance coincidence about ^219Rn also are derived. Meanwhile,for the ^220Rn flow regime is difficult to meet the condition of calculation formulas, a solution to solve the survival factor and decay factor is presented and the error coming from the use of theoretical calculation formula is avoided. Experiment system is established for measurement of 219^Rn in the 222^Rn,219^Rn mixed radon gas and 222^Rn,220^Rn,219^Rn mixed radon gas. The results show that 219^Rn of decay rate of 7 dpm ~ 25 dpm can he measured by the system with error of ＋ 8% ,when the background count rate is about 7.5 cpm. The study also demonstrates that low-level 219^ Rn can be discriminated and measured in the mixed radon gas via delayed coincidence method.

关 键 词：延迟符合法 氡混合场 偶然符合 存活因子 衰变因子 

分 类 号：TL822[核科学技术—核技术及应用]