载能α粒子在空气中诱发氮气荧光产额的蒙卡模拟研究

Monte Carlo Simulation of Nitrogen Fluorescence Yield Induced by Alpha Particles in Air

基于氮气荧光原理的远程α成像探测技术是一种极具应用前景的大范围核探测手段,其中对于载能α粒子在空气中诱发氮气荧光产额研究是探测成像技术的关键。利用Geant4建立荧光物理模型,结合收集整理文献报道的实验数据,模拟载能α粒子在空气中电离、诱发荧光和荧光光子猝熄的整个过程,并将模拟结果与文献中实测成像结果进行了比较分析。结果表明,荧光物理模型能很好地模拟再现成像结果。该模型的建立对后续工程技术中成像信噪比、成像时间、可测活度下限、面源尺寸分辨等关键性指标设计提供了技术支撑。

The long-range imaging and detection technology for alpha rays based on the nitrogen fluorescence induced by alpha particles is a promising large-scale nuclear detection method.However,the precisely known fluorescence yield is the ssue.Geant4 toolkit is used to establish a fluorescence physical model,combined with the experimental data reported in the literature,to simulate the whole process of ionization,fluorescence producing and fluorescence quenching.The simulation results have been compare with the experiment results in the literature,and it show that the physical model can reproduce the imaging results well.The establishment of this model provides technical support about the key indicators such as imaging signal-to-noise ratio,imaging time,lower limit of measurable activity,and surface source size resolution in subsequent engineering technologies.