Absolute Measurement of Radioactive Gas 85Kr Activity Concentration Using a Digitizer
TUO Fei1,LU Tianxiang2,ZHANG Ming3,ZHOU Qianqian3,GUO Guiyin4,WANG Shuo1
1.National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing 100088,China
2.National Center for Occupational Safety and Health, NHC, Beijing 102308,China
3.National Institute of Metrology, Beijing 100029, China
4.Suzhou Nuclear Power Research Institute Co., Ltd, Suzhou, Jiangsu 215004, China
Abstract：Based on the length compensation method absolute measurement system for gas-filled proportional counters established by the National Institute of Metrology, this study utilizes the DT5730 digital analyzer developed by CAEN to replace multiple traditional analog electronic modules. The digital analyzer is employed to collect, reconstruct, and analyze β signals offline to perform the absolute measurement of the activity concentration of 85Kr radioactive inert gas.The influence of various conditions is experimentally studied, and the absolute measurement results of 85Kr activity concentration are obtained by correcting the proportional counter end effect, the proportional counter wall effect, background, noise, dead time leakage counts, and sub-threshold counts.Under the same threshold, with a main magnification factor of 100 times, gas pressure of 50.5kPa, and operating voltages of 1675V and 1700V, the relative deviations of 85Kr radioactive activity concentration measurements between the digital analyzer and the electronic modules are 0.83% and 0.74%, respectively. The measurement results are consistent within the uncertainty range, proving that the digital analyzer can effectively replace traditional electronic modules for the absolute measurement of the 85Kr activity concentration.
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2024, Vol. 45 
