Study of Gas Pressure Dependence in the Multi-wire Proportional Counter on the Absolute Measurement for Alpha and Beta Sources Surface Emission Rates
LI Yu-qi1,2,WANG Ren-sheng3,ZHANG Ming1,ZHANG Jun-wei4,YANG Zhi-jie1,5,LIANG Jun-cheng1
1. National Institute of Metrology, Beijing 100029, China
2. East China University of Technology, Nanchang, Jiangxi 330013 China
3. Medical College of Soochow University, Suzhou, Jiangsu 215006, China
4. Institute of Modern Physics, Chinese Academy of Science, Lanzhou, Gansu 730000, China
5. China University of Geosciences, Beijing 100083, China
Abstract In order to the investigation of the absolute measurements for α and β surface emission rates due to the working gas pressure variations in China NIM by using α and β multi-wire proportional counter. The surface emission rates measurement of plane sources 241Am、204Tl and 90Sr/90Y is measured respectively by changing working gas pressure in multi-wire proportional counter. The counting rate loss of small pules is corrected by the threshold extrapolation method. The results show that by taking in to account the counting loss of small pules, there is no significant difference observed and all of the measured emission rates are consistent in the range of the evaluated uncertainty within the range of 50 kPa to 180 kPa atmosphere. Monte Carlo simulations based on Geant4 code were also carried out to support our results. The results obtained by the Monte Carlo method are in agreement with the experimental results.
LI Yu-qi,WANG Ren-sheng,ZHANG Ming, et al. Study of Gas Pressure Dependence in the Multi-wire Proportional Counter on the Absolute Measurement for Alpha and Beta Sources Surface Emission Rates[J]. Acta Metrologica Sinica, 2019, 40(1): 153-158.
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2019, Vol. 40 
