闪烁室测氡不同时刻的刻度因子研究

Study on calibration factor of radon measurement in scintillation chamber at different times

为了快速标定闪烁室的氡浓度,本文提出一种无需通过实验就能得到闪烁室测氡不同时刻的刻度因子来标定氡浓度的方法.该方法首先利用Geant4模拟了ST-203闪烁室内氡及其子体不同能量α粒子的探测效率,再基于取样3 h平衡后其刻度因子与闪烁室内氡及其子体平均探测效率的关系,然后根据氡及其子体的衰变规律,建立了闪烁室不同时刻的刻度因子计算方法.基于上述方法,本文利用ST-203闪烁室开展不同时刻测氡的刻度因子实验研究,其理论值和实验值的偏差小于5%.由闪烁室结构直接确定不同时刻测氡刻度因子的方法,能够快速标定闪烁室的氡浓度.

In order to calibrate the concentration of radon in the scintillation chamber quickly,this paper proposes a method to calibrate the radon concentration by obtaining the calibration factor of measuring radon in scintillation chamber at different times without any experiments.Firstly,Geant4 was used to simulate the detection efficiency ofαparticles with different energies of radon and its daughters in ST-203 scintillation chamber,then based on the relationship between the calibration factor and the average detection efficiency of radon and its daughters in the scintillation chamber after 3 hours of sampling and equilibration,and according to the decay law of radon and its daughters,the calculation method of the calibration factor at different times in the scintillation chamber is established.Based on the method above,the calibration factor of radon measurement at different times were studied by using ST-203 scintillation chamber.The results show that the errors between the theoretical and experimental calibration factors of the scintillation chamber at different times are less than 5%.Therefore,the radon concentration in scintillation chamber can be quickly calibrated by directly determining the radon calibration factors at different times from the structure of scintillation chamber.