Research on field emission theory and electronic transmission characteristics of miniaturized low voltage electron gun

Miniaturized and low-power particle detectors are wildly used in space exploration, and it is very important to develop miniaturized and low-energy electron source with micro-nano technology. In this study, based on the field emission theory and using carbon nanotubes as the cathode material of electron gun, the calculation method of the threshold value of open voltage on the surface of carbon nanotubes is proposed, and a model of electronic optical lens for four electrodes structure are constructed. By using multiple physics simulation software COMSOL, the structure parameters such as the distance between the deceleration lens and the anode, the thickness of the deceleration lens, the radius of the deceleration lens and the electrical parameters such as the voltage of the anode are simulated in this paper. According to the results, the divergence angle of the electron beam can vary from 18° to 33° by optimizing the structure parameters of the deceleration lens, and the energy of the electron beam is continuously adjustable in the range of 110 eV-135 eV. In addition, by adjusting the anode voltage, the divergence angle of electron beam can be further varied from 12° to 37° and the energy of electron beam can be continuously adjusted in the range of 95eV-145eV.