γ能谱法分析放射性核素时对γ射线全能峰干扰的修正  

The discussion on gamma-rays characteristic peak interference correction method when analyzing radionuclide activity with gamma spectrometry

作　　者：杨秀玉 孟纪群 李庆光 韦应靖[2] YANG Xiuyu;MENG Jiqun;LI Qingguang;WEI Yingjing(404 Company Limited,CNNC,Lanzhou 732850;China Institute for Radiation Protection,Taiyuan 030006)

机构地区：[1]中核四○四有限公司,兰州732850 [2]中国辐射防护研究院,太原030006

出　　处：《辐射防护》2021年第5期415-421,共7页Radiation Protection

摘　　要：针对在中核集团公司核电厂和“两厂两院”环境监测实验室比对中γ能谱分析存在的γ射线全能峰干扰问题,开展土壤中铀、钍、镭、钾、铯等γ核素测量实验。天然土壤标准源对谱仪进行效率刻度时,分析γ射线特征峰是否受到其它射线干扰,对受到干扰的γ射线通过修正代入效率计算的核素活度值以实现效率的拟合。由谱仪分析软件分析样品核素活度时,当利用不同特征γ射线计算的核素活度相差较大时,应进行活度修正。分析用于核素活度计算的γ特征峰(如^(235)U 185.7 keV,^(238)U 92.6 keV)受到的干扰峰,计算干扰峰对测量能谱峰(重峰)活度贡献,扣除干扰峰活度,即为γ特征峰贡献,由此给出样品核素活度值。这种方法在中核集团土壤样品比对中报出的^(238)U、^(226)Ra、^(232)Th、^(40)K和^(137)Cs数据全部合格。Aiming at the problem of gamma-ray characteristic peak interference correction in gamma spectrometry during a CNNC Environmental monitoring labs comparison,this paper conducts measurement experiment of uranium,thorium,radium and potassium in soil.When calibrating the efficiency of the spectrometer with natural soil standard source,it is necessary to analyze whether the gamma-ray characteristic peaks are interfered by other rays,and correct the efficiency by modifying the Nuclide activity value when calculating efficiency.When analyzing the nuclide activity of the samples by Gamma-Vision software,the activity correction should be carried out if the nuclide activity calculated by different characteristic rays is quite different.The characteristic peaks(such as ^(235)U 185.7 keV,^(238)U 92.6 keV)used in the calculation of nuclide activity are analyzed,the contribution of the interference peak to the measured energy spectrum(Overlapping Peak)activity is deducted.This method gives qualified ^(238)U,^(226)Ra,^(232)Th,^(40)K and ^(137)Cs data in CNNC soil sample comparison.

关 键 词：Γ能谱法 特征峰干扰校正 软件分析法 

分 类 号：TL751[核科学技术—辐射防护及环境保护]