Simulation study on a gridded micro-focus X-ray electron gun based on carbon nanotube cathode

A gridded micro-focus X-ray electron gun based on carbon nanotube cathode has the advantages of small volume, clear imaging and high temporal resolution compared with the conventional X-ray source. An array of CNT bundle is simulated to reduce the electric field screening effects for achieving stable large current density. The gridded electron gun based on carbon nanotube cathode is simulated by three-dimensional particle in cell simulation software in order to develop micro-focus X-ray tube in this paper. A structure of triode is adopted to obtain high compression ratio of electron beam spot. Simulation results show that 80kV/2mA electron beam with a beam spot radius of 0.1mm is obtained when the cathode radius is 0.4mm, and compression ratio is 16.