Abstract: The measurement of secondary electron emission coefficient is very important for the development of vacuum electronic devices. To measure the secondary electron emission coefficient of materials with low electrical conductivity, it is necessary to design a high performance electron gun with adjustable energy, beam spot diameter, deflection and pulse. According to the performance index of the electron gun, its electron emission, electron optical system and potential relationship are preliminarily designed. The pulse emission of electron beam was realized by applying pulse voltage to the control pole. The CST software was used to model and simulate the electron gun, the influence of focusing pole voltage on the beam spot size was obtained, and the effect of the deflector electrode was simulated. The results show that when the cathode voltage is -1000V, the control electrode voltage is -1005V, and the first anode voltage is -880V, as the focusing voltage increases from -400V to 1000V, the beam spot diameter increases from 0.2mm to 10mm, the relationship between them is almost directly proportional. The quadrupole electrostatic deflector is more suitable for use in the same space by comparing two deflection components. When the working distance is 30mm and the deflection voltage is 200V, the deflection sensitivity can reach 34mm/kV and the corresponding deflection angle is 12.8°. The design of the electron gun is reasonable and meets the requirements of the index, it can be used to measure the secondary electron launcher.

Key words: electron gun, electron optical system, CST simulation, secondary electron