Study of High Compression Ratio Cold Cathode Electron Gun

As the traveling wave tube operating frequency moves toward terahertz, the electron injection channel shrinks dramatically, which puts higher demands on the electron gun. In this work, we designed a high compression ratio cold cathode electron gun to fulfill the requirements of terahertz traveling wave tubes. Through the implementation of curved cathode for electron, as well as curved prefocusing electron, curved gate and anode configuration, CST simulation results indicate the extraction of an emission current of 10 m
$A$
from a carbon nanotube cathode with a radius of 0.4 mm at an operating voltage of 14 kV. Subsequently, the electrons undergo compression electron beam with a radius of 0.056 mm, thereby achieving an area compression ratio of approximately 51.