Separators of radon and thoron daughter aerosol

To improve the detectable limit of radioactive aerosol monitors, it is very important to eliminate the interference of the natural background, i.e. radon and thoron daughter aerosol. A particle size selective separator is used as artificial radioactive aerosol sampler. This separator may keep artificial aerosol from the natural radon and thoron daughter aerosol base on their different particle sizes. With the aid of the separator, most of natural background aerosol can be rejected in sampling radioactive aerosols, which is very helpful to improving sensitivity of the radioactive aerosol monitors. The separation principle and calibration method of the separator are presented, test results are given, and some problems one must pay attention to are discussed in the paper