中文摘要：

基于最优化电离室设计的AlphaGUARD测氡仪是目前国内外最稳定准确的商用氡探测器,其作为氡测量标准传递装置广泛应用于国内外各个氡室中。在通常氡浓度水平下,该仪器基于脉冲电离室工作原理,只记录α粒子计数,不能甄别能谱,故只能使用于纯222Rn环境的测量。为研究该仪器对环境中有可能存在的钍射气的响应,本文从AlphaGUARD测氡仪两种工作模式下220Rn响应机理出发对Alpha-GUARD测氡仪的220Rn响应系数S进行了实验研究。研究结果表明：流气模式下,采样流速为1.0L.min-1时,220Rn的流速修正因子R为0.80;扩散模式下220Rn响应系数S不随220Rn浓度和222Rn/220Rn混合浓度比的变化而变化,为6.09%。

英文摘要：

Based on optimized-design ionization chamber,AlphaGUARD is the most stable commercial radon detector,which is widely used in various radon chambers worldwide as a standard device.Under ordinary radon concentration,it works according to the principle of pulse ionization chamber which only records the α-particle counting without the spectroscopy,so it is limited to pure 222Rn measurements.In this paper,the two working modes of response mechanisms of AlphaGUARD to 220Rn were studied.This study found that,under flow mode with sampling flow rate of 1.0 L·min-1,the flow correction factor for 220Rn is 0.80;under diffusion modes,the relative sensitivity coefficient of 220Rn is independent on the 220Rn concentration and mixed 222Rn/220Rn ratio is 6.09 %.