基于数字多道NaI(Tl)探测器的死时间研究

在放射性测量中,有时候需要对计数率进行精确的测量,因此需要对探测器死时间效应进行修正处理。本文基于DMCA-iCore数字化多道模块,从理论出发分析了数字多道NaI(Tl)探测器产生死时间效应的原因,得出数字多道死时间也服从扩展型分布的结论;同时根据牛顿迭代法推导了死时间修正函数,在计数率较高、探测器死时间较大时该修正函数依然有较好的修正效果。基于双源法测试了系统的死时间,死时间t=20.6 μs,最后在¹³⁷Cs标准剂量场中对NaI(Tl)探测器进行了测试,进一步证明了修正方法的有效性。

Research on dead time of NaI(Tl) detector based on digital multichannel analyzer

There is dead time in the measurement of radiation by any detector. When the radiation intensity is too high and the current radiation has not been fully processed by the detector, the following radiation may not be processed, resulting in the loss of count. In practical measurement, it is necessary to accurately measure the count rate of the radiation and it is necessary to correct the dead time effect. In this paper, the dead time of the NaI(Tl) detector based on digital multichannel analyzer is analyzed theoretically and the correction method is studied. The dead time is measured by the dual source method and the effectiveness of the correction method is verified in ¹³⁷Cs radiation field.