PIPS-低本底α、β测量影响因素的研究

Research on Influencing Factors of PIPS-low Backgroundα,βMeasurement

PIPS(passivated ion-implanted planar silicon)探测器作为低本底α、β活度分析的发展方向,其影响因素有很多。为了探究PIPS探测器影响因素对低本底α、β测量仪性能的影响,采用PIPS-低本底α、β测量仪、^(239)Pu平面源和^(90)Sr平面源等试验器材,用改变探测器工作偏压、探测距离及真空度的试验方法,进行α、β和本底测量,分析测量结果,再根据本底计数率、探测效率和串道比的极差与仪器分级差值的比值研究了偏压、源距和真空度对测量的影响。结果表明:源距较偏压和真空度对PIPS-低本底α、β测量仪的影响更大,尤其体现在探测效率上,增大源距使α探测效率的极差与仪器分级差值的比值达到2.593,β探测效率的极差与仪器分级差值的比值为0.479。偏压和真空度对测量性能的影响都很小。

PIPS(passivated ion-implanted planar silicon)detector is the development direction of low backgroundαandβactivity analysis.In order to explore the influence of PIPS detector influencing factors on the performance of low backgroundα,βmeasuring instrument,PIPS-low backgroundα,βmeasuring instrument,^(239)Pu plane source and ^(90)Sr plane source and other test equipment are used to change the working bias of the detector,the distance between the detector and the radioactive source or the degree of vacuum,and it carries outα,βand background measurement,analyzes the measurement results,and then studies according to the ratio of the background count rate,detection efficiency and cross-channel ratio range to the instrument classification difference.The results show that the source distance has a greater impact on the PIPS-low backgroundαandβmeasuring instrument than bias voltage and the degree of vacuum,especially in the detection efficiency.Increasing the source distance makes the ratio of the range of detection efficiency and the difference value in instrument classification reached 2.593,and the ratio of the range of detection efficiency and the difference value in instrument classification was 0.479.Bias voltage and vacuum degree have little influence on the measurement.