一种提高样品放射性活度测量准确度的新方法

A new method to improve the accuracy of radioactivity of sample

在使用高纯锗γ谱仪测量样品的放射性活度时,探测器对γ射线的探测效率是影响测量准确度的一个重要因素.目前使用的两种得到探测效率的方法——标准样品法和蒙特卡洛法,因为各自的局限性,都存在一定的系统误差.结合两种方法,提出并建立了一种能够消除前两种方法系统误差,获得更准确的探测效率的新方法,即用蒙特卡洛方法计算待测样和标准样的探测效率的比值,再乘以实验测量得到的标准样的探测效率,得到待测样品的探测效率.所建方法的正确性通过蒙特卡洛软件计算的模拟实验得到了验证,并证明了新方法能够完全消除标准样品法的系统误差,并且在绝大多数情况下消除了蒙特卡洛法的系统误差.

Detection efficiency of gamma rays is an important factor to affect the measurement accuracy of radioactivity.There are two methods to acquire detection efficiency currently,the standard sample method and Monte Carlo method.Both methods have their own problems which would result in system error of detection efficiency.A new method based on the above two methods is proposed.In this method,the detection efficiency ratio of the tested sample to the standard sample was calculated through Monte Carlo method,multiplied by the detection efficiency of the standard sample obtained from the experiment,then the detection efficiency of sample tested is acquired.The correctness of the new method was verified by Monte Carlo software and proved that this new method could avoid the system errors from the standard sample method entirely and Monte Carlo method in most cases.