This paper introduces a new software delayed coincidence counting technology,which requires less storage space. An experiment system was established for measurement of lowlevel220Rn. The methods were validated experimentally by intercomparison measurements. The results show that220Rn of decay rate of between 3dpm~20dpm can be measured by the experiment system with error of ±2%, when the background count rate is of 2dpm~4dpm. &cop...
