Hirosaki University, Hirosaki, Japan.
Radiat Prot Dosimetry. 2022 Sep 9;198(13-15):904-908. doi: 10.1093/rpd/ncac004.
Researchers have used various methods to obtain the exhalation rates of radon and thoron from soil and building materials. One of the typical methods for radon exhalation rate is the circulation method using an accumulation container, an external or internal sampling pump and a continuous radon monitor. However, it is necessary to consider sampling flow rate if this method is applied to exhalation rate measurement for thoron due to its short half-life. Based on a calibration experiment, the measured thoron concentrations obtained by an electrostatic collection type radon and thoron monitor (RAD7) were found to be influenced strongly by the sampling flow rate. It was also found that the thoron exhalation rate from a soil sample depended on the pressure difference which was proportional to the increasing sampling flow rate. The thoron exhalation rate measured at the generally used sampling flow rate of the internal sampling pump of the RAD7 was overestimated compared with the value at 0 L min-1.
研究人员已经使用了各种方法从土壤和建筑材料中获得氡和钍射气的呼出率。其中一种典型的氡呼出率循环方法是使用积累容器、外部或内部采样泵和连续氡监测器。然而，如果将该方法应用于钍射气的呼出率测量，由于其半衰期较短，需要考虑采样流速。基于校准实验，发现静电收集型氡和钍监测器（RAD7）测量得到的钍射气浓度强烈受到采样流速的影响。还发现，土壤样品中的钍射气呼出率取决于压差，而压差与采样流速的增加成正比。与 RAD7 内部采样泵的 0 L min-1 采样流速相比，在通常使用的 RAD7 内部采样泵的采样流速下测量的钍射气呼出率被高估了。
