Study on influence factors of the measurement of radon exhalation rate by activated carbon-gamma spectrum method

In the experiment of activated carbon-gamma spectrum method to measure the radon exhalation rate, selection of sampling time significant affect the measurement, through the experiment we can found that radon in the carbon layer need some time to evenly distributed. When the radon distribution in the carbon layer is uniform, results are similar in different sampling time. Thus the measurement deviation can be minimized due to difference in sampling time, and the back-diffusion effect need not to be considered in this method. (authors)