激光暗荧光光谱电场测量微扰计算与实验

Calculation and experiment of tiny perturbations in electric field measurement for the laser-induced fluorescence-dip spectroscopy method

为了实现强流脉冲电子束对材料表面改性的工业化应用,需要对电子束的作用过程进行实时微扰监测。电场强度是反映电子束特性的关键参数之一,基于Stark效应的激光暗荧光光谱可实现对环境电场的微扰测量。因此,开展激光功率密度对环境电场的影响研究,对此类电场测量方法的参数设置和结果判断具有重要的理论和应用价值。通过理论分析和计算得出电场测量微扰状态下的激光功率密度与试验环境的关系模型。基于上述关系模型,搭建测试平台,验证激光功率密度对电场测量微扰的情况。实验结果表明:在示踪气体氙气压强为1.0×10^(-4)mbar、电场强度不大于2 kV/cm的条件下,对电场测量微扰的激光功率密度值为5 MW/cm^(2),与理论计算值基本一致。研究结果填补了激光暗荧光光谱诊断方法中激光功率密度对电场影响定量分析的空白,可应用于同类电场测量方法中,为激光功率密度与实验参数的设置提供依据和参照,有效支撑电场测量实验的开展,有效提升电场测量的准确性。

In order to realize the industrial application of high-current pulsed electron beam on material surface modification,it is necessary to monitor tiny perturbation in real-time.The electric field strength is a critical parameter understanding the characteristics of electron beams.The laser-induced fluorescence-dip spectroscopy method based on the Stark effect can realize the tiny perturbation measurement of electric fields.Therefore,Studying laser power density influence on the electric field has significant theoretical and application value for the parameter setting and result interpretation of similar electric field measurement methods.The theoretical analysis and calculation are used to obtain the relationship model between excitation laser power density and the test environment parameters in the tiny perturbation state of electric field measurement.Then,based on the above relationship model and theoretical calculation,the influence of excitation laser power density on electric field measurement is verified experimentally.The experimental results show that under the conditions that the tracer gas xenon pressure is 1.0×10−4 mbar and the electric field strength is 2 kV/cm or below,the excitation laser power density of tiny perturbations on the electric field measurement is 5 MW/cm2,which is consistent with the theoretical calculation value.The research results provide a quantitative analysis method for studying the influence of laser power density on the electric field in the laser-induced fluorescence-dip spectroscopy.They can be applied to similar electric field measurement methods,open the way for the setting of laser power density and experimental parameters,support the development of electric field measurement experiments,and effectively improve the accuracy of electric field measurement.