【摘要】 放射性气体氙是全面禁止核试验条约组织重点关注的监测对象,准确测量放射性氙的活度是其中的难点之一。本文详细介绍了β-γ符合效率外推法测量放射性核素活度的原理和方法,使用该方法绝对测量了¹³¹Xe^m活度,测量不确定度为0.3%（k=1）。根据外推法原理推导了参数法测量¹³¹Xe^m活度的计算公式,外推法与参数法活度结果相差2.0%。实验中同时用HPGeγ谱仪对¹³¹Xe^m进行了活度比对测量,其结果与符合外推法测量结果相差2.7%,二者结果在置信水平（k=1）区间范围内一致。以上结果表明,β-γ符合效率外推法显著提高了¹³¹Xe^m活度测量的准确度。更多还原

【Abstract】 Radioactive gas xenon is one of the important components for International Monitoring System（IMS）of Comprehensive Nuclear-Test-Ban Treaty（CTBT）.It is a difficult problem that the activity of radioactive xenon can be accurately measured.The principle ofβ-γcoincidence efficiency extrapolation method was described in detail in this paper.The activity of ¹³¹Xe^m was absolutely determined byβ-γcoincidence efficiency extrapolation method,and its standard uncertainty of measurement is 0.3%.According toβ-γcoincidence efficiency extrapolation method,parameter method formula of ¹³¹Xe^m activity was deduced.And ¹³¹Xe^m activity result difference of these two methods is2.0%.In addition,the activity of ¹³¹Xe^m was determined by HPGeγspectrometry,and the discrepancy of measurement results between coincidence efficiency extrapolation method and HPGeγspectrometry is 2.7%.The above results indicate that the meas-urement accuracy of ¹³¹Xe^mactivity is improved significantly byβ-γcoincidence efficiency extrapolation method.更多还原