中文摘要：

基于AB-5型便携式测222Rn仪,本研究开发了一种快速测量220Rn浓度的新方法。采样前排空闪烁室内空气并测量其本底计数,采样后即刻测量1 min,利用采样前后的每分钟计数和理论探测效率,进而计算出220Rn浓度。理论计算结果表明,在纯220Rn的环境条件,该方法的测量下限可达约65 Bq.m-3（置信度70%）;比对实验结果表明,不论是在纯220Rn或222Rn/220Rn混合的环境中,该方法的测量结果与RAD-7型电子测氡仪的测量值偏差均在±10%之内。AB-5型便携式测氡仪也可用于220Rn浓度的定量测量,该测量方法快速且操作简便,有一定的应用价值。

英文摘要：

Based on the portable radon measurement device AB- 5, we developed a new method for measuring the concentration of thoron. First pump out the air in Lucas scintillation cell, then measure the background count for 10 min, after that measure for 1 min immediately after sampling, using the counts before and after sampling and also the theoretical detection efficiency, thus calculate the thoron concentration. Theoretical calculation results show that in pure thoron condition, the lower detection limit of Thoron is about 65 Bq·m^-3 （confidence level 70% ）; The comparison results show that both in a pure Thoron or Radon/Thoron mixed condition, the deviations between this measuring method results and the RAD - 7＇ s （ a static-electronic measuring device） measurement results were less than ＋ 10%. AB-5 can also be used for quantitative measurement of Thoren concentration because of its fast and simple.