Background: Filter membrane is an important part of the balloon emanometer. The membrane of high filtration efficiency but little self-absorption can not only improve the sampling rate

but also reduce the measurement error effectively. Purpose: The experiment aims to compare the performance of three different filter membrane materials. Methods: Based on the radon and its progeny collecting physical processes on the membrane

we deduced the collection of radon in filters and its decay variation with time. Through the experiment

the filtration efficiency and self-absorption factor of the three different membranes have been tested. Results: When the thickness is almost the same

the filtration efficiency of Polytetrafluoroethylene (PTFE) filter and nylon filter is higher than that of commonly used glass fiber filter and its self-absorption is better than that of glass fiber membrane. The air resistance of PTFE filter is the best. It can effectively improve the performance by increasing thickness of the glass fiber filter membrane. Conclusion: This is not only a good reference for the selection of filter membrane in radon measurement with balloon method

but also applicable to radon-measuring devices with other methods. Abstract