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针对一款高时空分辨率飞秒条纹变像管的带极靴磁透镜结构,提出了更加符合实际磁场分布规律的“高斯型”磁场分析模型,并且研究了磁透镜内径比对条纹变像管时间、空间分辨特性的影响。利用Lorentz软件数值研究了条纹变像管中不同内径比的磁透镜所产生的磁场分布,并且采用Monte-Carlo方法对大量光电子初始参量进行抽样计算,通过跟踪行波偏转前置短磁聚焦条纹变像管中大量光电子的运行轨迹,统计分析了光电子在最佳像面上的位置分布,最后利用调制传递函数对条纹管时空分辨能力进行评价。结果表明:当磁透镜内径比r1/r2=0.83时,磁场对电子束进行有效聚焦,获得物理时间分辨率优于190 fs,且狭缝边缘(狭缝总长度为6 mm)空间分辨率达到100 lp/mm的结果。
Aiming at the structure of a pole piece magnetic lens with a femtosecond stripe tube with high space-time resolution, a “Gaussian” magnetic field analysis model that is more in line with the actual magnetic field distribution is proposed. Like tube time, spatial resolution of the impact. The Lorentz software was used to numerically study the magnetic field distribution of the magnetic lens with different inner-diameter ratios in a striped tube. Monte-Carlo method was used to calculate the initial parameters of a large number of photoelectrons. The tracking short- Like a large number of optoelectronic tube trajectory, the location of the photoelectron on the best image plane is statically analyzed. Finally, the modulation transfer function is used to evaluate the space-time resolution of the stripe tube. The results show that when the ratio of the inner diameter of the magnetic lens to r1 / r2 = 0.83, the magnetic field can effectively focus the electron beam to obtain a physical time resolution of better than 190 fs and the spatial resolution of the slit edge (total slit length of 6 mm) 100 lp / mm results.