γ-γ符合法测量正电子源活度实验教学研究

Teaching Experiment and Research of Measuring Activity of the Positron Source with the Method of γ-γ Coincidence

在核物理基础实验研究中,放射性活度是最直接、最重要的参数。符合法测量因其可以排除探测效率等因素对测量结果的影响,被广泛应用于放射源活度的精确测量。该文针对传统实验教学的不足,首次设计并实现了用于符合测量的探测器实验平台,搭建了一套利用符合法测量正电子源活度的实验系统。基于该系统,完成了γ-γ符合法测量^(22)Na的绝对活度。同时,指出了实验的重点和难点,为符合法测量正电子源活度实验教学提供了一个参考。

In the basic experimental research of nuclear physics,the radioactivity is the most direct and important parameter.The method of coincidence measuring is widely used in the precise measurement of radioactivity,because it can eliminate the influence of the detection efficiency and other factors on measuring results.Aiming at the shortcomings of traditional experimental teaching,a detector platform was proposed and designed for the coincidence measurements for the first time,and a set of experimental system for measuring the activity of the positron source with coincidence method was established.Based on this system,the absolute activity of22 Na was measured by theγ-γcoincidence method.At the same time,the emphasis and difficulty of the experiment were pointed out,which provides a reference for the teaching experiment of measuring the activity of positron source.