可控聚焦型减速场能量分析器的设计分析

Design and analysis of retarding field energy analyzer with controllable focusing voltage

基于之前减速电场能量分析的设计与实验,针对实验中出现的绝缘性不好、能量分辨率不高等问题,对原结构进行了改进与仿真分析,以更好地实现行波管电子枪电子注及注波互作用后电子注参数的精确测量和分析,为行波管的设计、性能改进和研制提供参考。该可控聚焦型减速场能量分析器结构将高压圆筒与减速栅网进行电气绝缘隔离,并在二者之间设置一个可控的小电压,产生的第二个静电透镜对发散的电子注产生加速会聚的作用,以削弱在第一个透镜聚焦作用的薄弱区域空间电荷效应及电子注发射角等因素对注发散的影响,调整粒子轨迹倾斜度和分辨率。同时,整体结构在不影响测试精度的情况下向小型化和轻型化发展。应用CST粒子工作室对不同粒子界面处粒子分布及整体场结构进行模拟,然后用Matlab软件进行数据处理并导出关键参数。着重分析结构性能的优化和提升在分辨率及半峰值全宽度等参数上的体现。结果表明该能量分析器适用于几keV到10keV的强流电子注的测量。

In order to solve the problems of poor insulation, low resolution and sparking etc. , a retarding field energy analy zer is upgraded, simulated and analyzed to test and analyze the electron beam parameters accurately, which derive from the guns of traveling wave tubes and beams after beam wave interaction, providing a reference for the design, performance improvement and development of the traveling wave tubes. The retarding energy analyzer with a controllable focusing voltage insulates high voltage cylinder electrically from retarding mesh and applies a controllable small voltage between them. The second electrostatic lens accelerates and focuses the diverging beam near the area of the mesh, to weaken too much expansion in the region of the weak part that the first lens functions, due to space-particle effects and beam emittance, etc. and optimize the slope of the particle traj- ectory and resolution. Meanwhile, the whole structure tends to miniaturizition and lightweight. A computer code called CST is used to simulate the particle distribution in particle interfaces and the whole electric field distribution, and Matlab code helps data processing and exports the key parameters. Besides, the paper focuses on analyzing the optimization and improvement of the per formance reflected by the resolution and Full Width at Half Maximum, etc. The result shows that this energy analyzer is compe- tent to apply to the experiments of electron beams.