According to the performance parameters and structure position of the design target

the initial value of the gun is obtained by the comprehensive iteration method. Moreover

the performance of tungsten and LaB6 cathode materials was compared

the appropriate cathode materials were selected

and the 60 kV space electron gun was simulated by using the SOURCES related procedures

and the simulation results such as coefficient of chromatic aberration and beam spot diameter were obtained. According to the focal length formula

the focal length of the first-order focusing system is obtained and the simulation results of the focusing system

such as focal length

beam spot and optical path diagram

are obtained. By analyzing the shortcomings of the first stage focusing system

the second stage focusing system is redesigned

and the performance parameters such as pole shoe hole diameter

coil excitation and the distribution map of the electromagnetic lens axis are obtained by simulation. Finally

the parameters of electron gun and electron optics are obtained according to the simulation results of two-stage focusing system.