基于Geant4的分辨型剂量盒中^(220)Rn的探测效率研究

Study on the Detection Efficiency of Thoron in Discriminating Dose Box Using the Geant4 Monte Carlo Simulation Code

为了得到用于^(220)Rn测量的分辨型剂量盒中包裹不同厚度铝膜的剂量片探测效率,利用蒙特卡洛计算程序Geant4建立了φ8.0 cmX3.2 cm分辨型剂量盒模型,模拟了该剂量盒中a射线与空气、铝膜和CR-39剂量片的相互作用过程,确定了用于^(220)Rn测量的铝膜厚度,得到了包裹不同厚度铝膜的剂量片对^(220)Rn的探测效率,并在标准氢室和钍室内开展了验证实验。研究结果表明:当铝膜厚度为41μm时,Geant4模拟计算得到的探测效率为53.2%,与实验数值分析结果相对偏差为-5.6%,验证了模拟结果的正确性。所建立的计算模型可用于深入开展^(222)Rn和^(220)Rn的分辨测量研究。

In the purpose of getting the detection efficiencies of Thoron in CR-39 dosimeter with different thickness aluminum foils in discriminating dose box,simulation model has been built and the transportation of alpha particles in air,aluminum foil and CR-39 dosimeter has been simula-ted.The optimized thickness of aluminium foil is 40 fim to separate thoron from radon.The simulation result of detection efficiency of thoron with aluminium foil of 41/nm thickness is 53.2%,which has the relative deviation of-5.6%with the experiment result.The results between simulations and experiments show the reliability of simulation mode,which can be used to study in a deep-going way how to detect thoron.