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本文描述了一种低浓度氡的测量方法。氡衰变的子体用静电场收集到圆柱形收集室(φ156×210mm)的收集极上,收集时间为3小时,使氡与其子体平衡;用 ZnS(Ag)屏闪烁计数器测量氡子体的α放射性,以确定氡浓度。测量了氡子体在收集电极上的分布,研究了收集电压和含氡空气湿度对收集效率的影响。在收集电压为-3000V 和含氡空气为干燥空气的条件下,得到的平均收集效率约73%,测员装置对 RaA、RaC′,α粒子的2π探测效率约为95%,本底在0.3—1 cmp之间。当氡和它的子体达到平衡时,灵敏度约为6 cpm/[pCi/l(氡)]。
This article describes a method for measuring low concentrations of radon. The progeny of radon decay were collected on a collector of a cylindrical collecting chamber (φ156 × 210 mm) with an electrostatic field for a period of 3 hours to equilibrate radon with its daughter; the radionuclide was measured using a ZnS (Ag) scintillation counter Alpha radioactivity to determine radon concentration. The distribution of radon progeny on the collecting electrode was measured. The effect of collecting voltage and air humidity with radon on the collecting efficiency was studied. The average collection efficiency of about 73% was obtained when the voltage was -3000 V and the air containing radon was dry air. The detection efficiency of 2π for RaA, RaC ’and α particles was about 95% and the background was 0.3 -1 cmp between. Sensitivity is about 6 cpm / [pCi / l (radon)] when radon and its daughter balance.