用于HPGe探测器效率标定的模拟气体刻度源的研制

Design of Simulation Gas Calibration Source for Calibrating Peak Efficiency of HPGe Detector

准确校准测量系统的探测效率是HPGe探测器γ能谱法测量放射性气体活度的关键,放射性气体的半衰期一般较短且样品制备过程复杂,这些客观因素给效率校准工作带来很多不便。本工作提出了模拟气体刻度源的制备方案并进行了实验研究,所制备的模拟刻度源最小基质密度为0.043g/cm3,自吸收的影响小于0.5%。通过与效率参考值的比较表明,模拟气体刻度源的制备方案简单可行,所制备的模拟气体刻度源可代替气体标准源实现气体活度测量中HPGe探测器的效率校准以及探测效率的日常监督。

Calibrating the detection efficiency accurately is the key work to the gas activity measurement by HPGe detector gamma spectrometer method.The gas samples operation is difficult because of their state and characters,especially when the half-lives of gases are short.It is not convenient to calibrate the detection efficiency by real gas calibration source.The paper introduces a new calibration source named simulation gas calibration source,it can replace gas standard source to calibrate detection efficiency of HPGe detector and to monitor the stability of the detection efficiency daily.The matrix density of the simulation gas calibration source is only 0.043 g/cm3 and the self-absorption of this source is less than 0.5%.The efficiency calibrated by this source is in coincidence with reference value well.