Cold cathode electron gun based on single wall carbon nanotubes field emitters for THz traveling wave tube

A cold cathode electron gun for THz traveling wave tube (TWT) was designed. The single wall carbon nanotubes (SWCNTs) cold cathode was fabricated by screen printing with the radius of 0.1mm. The turn-on field of the SWCNTs cathode was 0.78V/um, and the field enhancement factor was 8500. The maximum emission current density exceeded 10A/cm
²
. Based on the field emission test, we designed a cold cathode electron gun with the beam waist radius of 0.03mm. And the area compression ratio of the electron gun is about 11. The emission current density and beam radius of the designed SWCNTs cold cathode electron gun have met the design requirements of THz TWT. field emission, cold cathode, electron gun, THz TWT