液闪法测量水中氚放射性活度的淬灭效应

采用液体闪烁计数法进行放射性同位素测量时存在淬灭效应,而且几乎每个样品的淬灭程度都不同,并影响测量精度。采用液体闪烁计数法测量水中氚的放射性活度,淬灭是难以避免的,因此要进行淬灭校正,才能使不同淬灭程度的样品的测量结果具有可比性。淬灭校正的方法有很多,外标准校正法是一种比较可靠的方法。文章采用氚外标准校正法进行实验,得出淬灭校正曲线即探测效率E与淬灭参数SQP(E)的关系式为E=0.001 3SQP(E)-0.707 6,经过样品验证,该曲线是可靠的。采用外标准校正法适合于大批样品的测量。

Quenching Effect of Tritium Radioactivity in Water Samples Analysis by Liquid Scintillation Counting Method

Quenching effect is always existed in the radioactivity measurements using liquid scintillation counting method and the quenching level is different for almost every samples, which influences the measurement accuracy and precision. Therefore quenching correction should be made in tritium radioactivity measurements for water samples when liquid scintillation method is used. In this paper, the tritium external standard calibration method was used for the correction of quenching effect. Through the experiments, the quenching calibration curve, namely the relationship between counting efficiency (E) and scintillation quenching parameter SQP, E=0.0013SQP(E)-0.7076, was established. The calibration method has been applied to the liquid scintillation measurements of tritium radioactivity in water samples with satisfactory results.