Kotrappa P, Jester W A
Rad Elec Inc., Frederick, MD 21701.
Health Phys. 1993 Apr;64(4):397-405. doi: 10.1097/00004032-199304000-00007.
This paper describes a simple and relatively inexpensive method of determining the concentration of dissolved 222Rn in water. The method involves a recently developed electret-passive environmental radon monitor, which uses an electret ion chamber. The procedure consists of sealing a known volume of a carefully collected water sample with one of these monitors in an exposure container and determining the average equilibrium 222Rn gas concentration in the air phase during the exposure time period. This average concentration can then be used to calculate the 222Rn concentration in the original water sample. Identical samples were analyzed both by this new method and by a standard liquid scintillation method, and the results were compared over a wide range of 222Rn concentrations. There was good agreement except that the electret ion chamber method gave results that were consistently lower by about 15%. This bias in the results was attributed to both 222Rn losses during sample handling and possibly to some errors in the assumptions made in the theoretical model. A correction factor is recommended to bring the results of this technique into agreement with the standard method. The procedures are simple and economical and can be easily employed by many primary 222Rn-measuring laboratories currently using these monitors for measuring indoor 222Rn.
本文介绍了一种测定水中溶解的222Rn浓度的简单且相对廉价的方法。该方法涉及一种最近开发的驻极体被动式环境氡监测仪，它使用一个驻极体电离室。该程序包括将已知体积的精心采集的水样与其中一个监测仪密封在一个暴露容器中，并测定暴露时间段内气相中的平均平衡222Rn气体浓度。然后，这个平均浓度可用于计算原始水样中的222Rn浓度。用这种新方法和标准液体闪烁法对相同的样品进行了分析，并在很宽的222Rn浓度范围内比较了结果。除了驻极体电离室法给出的结果始终低约15%外，两者吻合良好。结果中的这种偏差既归因于样品处理过程中的222Rn损失，也可能归因于理论模型中所作假设的一些误差。建议采用一个校正因子，使该技术的结果与标准方法一致。这些程序简单且经济，许多目前使用这些监测仪测量室内222Rn的主要222Rn测量实验室都可轻松采用。
