A Gridded High-Compression-Ratio Carbon Nanotube Cold Cathode Electron Gun

In order to develop field emission cold cathode radiation source devices, a gridded carbon nanotube (CNT) cold cathode electron gun is theoretically and experimentally investigated in this letter. The planar grid and annular CNT cold cathode are used and optimal parameters of a high-compression-ratio electron gun are obtained by particle in cell simulation software. A 4-mA/10-kV annular electron beam with an average radius of 1.75 mm is achieved based on a permanent magnet in the experiment. The area compression ratio of electron beam is ~10.