空气中人工核素的最大容许浓度一般都很低,而天然氧、钍射气子体不仅浓度高且变化大(一年四季不同,昼夜间最大可差一个数量级),对人工核素污染的监测带来一定困难。在所采用的方法中,“氡、钍子体α、β放射性浓度比值法”是比较简便易行的。我们对设备和测量方法稍加改进,测量装置由两套减为一套,鉴别灵敏度也有一定的提高。 一、方法 α/β比值法,是建立在“空气中天然氡、钍子体放射性平衡比基本不变”的原理上,只要每次采样时流量、采样总量固定,采样结束后到开始测量之间的时间间隔不变,计数 The maximum allowable concentration of artificial radionuclides in the air is generally low, while natural oxygen, thoron projectiles not only high concentration and great changes (different throughout the year, the largest difference between day and night an order of magnitude), artificial radionuclide pollution Monitoring brings some difficulties. In the method adopted, “radon, thorium α, β radioactive concentration ratio method” is relatively simple and easy. We have slightly improved the equipment and measurement methods, reduced the measuring device from two to one, and improved the discrimination sensitivity. First, the method α / β ratio method is based on the principle of “the natural radon in the air, thorium body radioactive balance substantially unchanged”, as long as the flow of each sampling, the total sample fixed, the sampling after the start of measurement The time interval between the constant count