低能量电子枪的仿真与优化

Simulation and Optimization of Low Energy Electron Gun

利用计算机模拟软件CST对电子枪结构进行建模,得到电子枪聚焦极不同的结构尺寸参数对电子束电流密度和束斑尺寸的影响结果。仿真结果表明:当聚焦极与控制极的距离Da和聚焦极厚度Db增大时,样品中心处电流密度减小但均匀性好,束斑半径增大;当聚焦极的半径r增大时,样品中心处电流密度增大但均匀性差,束斑半径减小。考虑中和效率、部件之间的放电和实际装配可行性,选取的优化参数分别为D_(a)=5 mm,D_(b)=0.8 mm,r=3 mm。对优化后的结构进行测试,电子束束流值提高约36%,电子束束斑调节范围增大。证明了利用CST仿真进行优化的可行性,同时达到了优化电子枪性能的目的。

Low energy electron gun is used to neutralize insulating or semiconductor materials in photoelectron spectrum.The energy can be adjusted from 50 to 500eV.It has the advantages of simple structure and easy operation.The computer simulation software CST is used to model the structure of the electron gun,and the effects of different structural size parameters of the electron gun focusing on the electron beam current density and beam spot size are obtained.The simulation results show that when the distance between the focusing electrode and the control electrode D_(a)and the thickness of the focusing electrode D_(b)are increased,the current density at the center of the sample is decreased with good uniformity and increased beam spot radius.When the radius r of the focusing electrode is increased,the current density at the center of the sample is increased with poor uniformity and decreased beam spot radius.Considering the neutralization efficiency,discharge between components and the feasibility of actual assembly,the selected optimization parameters are D_(a)=5 mm,D_(b)=0.8 mm and r=3 mm respectively.The optimized structure is tested,and the electron beam current value is increased by about 36%,and the adjustment range of electron beam spot is increased.The feasibility of optimization by CST simulation is proved,and the purpose of optimizing the performance of electron gun is achieved.