为发展场致发射冷阴极毫米波电真空辐射源器件, 对利用大面积碳纳米管冷阴极产生大电流、高电流密度电子注的电子光学系统进行了研究.通过在Pierce电子枪阴极表面引入栅网结构, 解决了碳纳米管冷阴极场致发射所需的强电场和电子聚束问题.在碳纳米管冷阴极实验测试数据的基础上, 采用粒子模拟软件对上述电子光学系统进行了仿真.研究了栅网对注电流、注腰半径和电子注散射的影响, 分析了阳极电压和外加轴向磁场对电子注的聚束作用.优化后的仿真结果表明在阴极发射面为3.03 cm2时, 该电子光学系统能够产生210 mA、60 kV, 电流密度为6.7 A/cm2, 最大注半径为1mm的电子注.

In order to develop millimeter wave electric vacuum radiation source devices with field emission cold cathodes, the electron-optical system using a large area carbon nanotube cold cathode (CNCC) was investigated, which can generate an electron beam with large current and high current density. By adding a mesh grid on the cathode surface of a Pierce electron gun, problems of the electron bunching and high electric field applied to the CNCC surface have been solved. Based on the experimental results of a CNCC, the field emission model was built, by using PIC simulation software, to simulate the Pierce electron-optical system. The effect of the mesh grid on the electron beam has been analyzed. And the influence of the anode voltage and the axial magnetic field for the electron beam radius has been researched. The simulation results of the electron-optical system showed that when the area of cathode is 3.03 cm2, an electron beam with 210 mA at 60 kV can be produced. The current density is 6.7 A/cm2 and the maximum radius of the electron beam is 1 mm.