光电阴极光电子发射特性的蒙特卡罗方法研究

Photoelectron emission characteristics of photocathode by Monte Carlo method

光电阴极发射光电子的时间特性影响条纹相机和电子衍射系统等时间分析仪器的时间分辨率.使用蒙特卡罗方法研究了光电子的能量、角度分布模型的随机抽样方法,对能量的余弦、Maxwell分布给出了快速的乘抽样方法.计算了光电子的余弦、Maxwell、Beta、Rayleigh、Henke分布等7种能量模型的时间弥散值.验证了时间弥散计算公式的弥散系数为2.643 kg^(1/2).A^(-1)·s^(-1),其与加速电场场强的指数关系为-0.996.该方法和结果在飞秒光电子传播动力学、飞秒条纹相机、飞秒电子衍射仪等领域有广泛应用.

Temporal characteristics of photoelectrons emitted by photoelectric cathodes affect the temporal resolution of time analysis instruments such as streak cameras and electron diffraction systems. Energy,angle distribution model and stochastic sampling method of photoelectrons are investigated by Monte Carlo method. The fast multiplicative sampling method is given for the cosine and Maxwell distribution of energy.Time dispersion values of seven energy models of photoelectron, such as cosine, Maxwell, Beta, Rayleigh and Henke distribution, are calculated. The dispersion coefficient of time dispersion formula is verified to be2.643 kg1/2·A-1·s-1, and the exponential relationship with the accelerated electric field strength is-0.996.The method and results are useful in the fields such as dynamics of femtosecond photoelectron propagation,femtosecond streak cameras, femtosecond electron diffractometer.