低水平α、β放射性测量仪器计量性能的测试分析

Testing and analysis of low-level alpha and beta radioactivity measuring instruments’ metering performance

低水平α、β放射性测量仪器通常采用闪烁体探测器和流气正比计数器探测器。参照JJG1100-2014流气正比计数器总α、总β测量仪检定规程和JJG 853-2013低本底α、β测量仪检定规程,实验测量了流气正比计数器和闪烁体型共15个型号的低水平α、β放射性测量仪器的本底、探测效率、串道比等主要性能参数,结果显示流气正比计数器总α、总β测量仪的本底较低、β探测效率较高,低本底α、β测量仪的α对β串道比较低,表明前者对β放射性的测量下限更低,后者较适用于α、β放射性混合样品的测量。

Scintillation detectors and gas-flow proportional counter detectors are the two types of instruments used in low-level alpha and beta radioactivity measurement. Refer to JJG 1100-2014 regulation of verification for Gas-Flow Proportional Counter Gross Alpha and Gross Beta Measuring Instruments and JJG 853-2013 Low Background Alpha/Beta Measuring Instruments, the key performance parameters such as instrumental background, detection efficiency and interfere ratio of low-level alpha and beta radioactivity measuring instruments with 15 types of gas-flow proportional counter and scintillation were measured experimentally. The results showed that, the background was lower, and the detection efficiency of beta is higher with regard to the gas-flow proportional counter gross alpha and gross beta measuring instrument, while the alpha-to-beta interfere ratio was lower with regard to the low background alpha/beta measuring instrument. The above results indicated that the former type of instrument owned better lower limit of beta radioactivity detection, while the latter performed better in alpha and beta radioactivity discrimination.