| With the vigorous development of micro satellite technology in modern aerospace field,the electric propulsion device of micro satellite has become an important research hotspot in aerospace field all over the world,and its reliability and service life have been significantly improved.The neutralizer is an important part of the electric propulsion device,which is used to neutralize the ion plume pollution excluded by the electric propulsion.For microsatellites,the neutralizer electronic source should have good electron emission performance,light weight,low power consumption and good anti-pollution ability.This paper presents a design scheme of neutralizing electron source with simple structure,low power consumption and stable field emission performance.La B6-Si array cathode is used as the cathode material of electron source.The grid and anode are designed.The overall structure is simulated and designed by opera-3D simulation software,and the structural parameters are continuously adjusted to complete the design scheme.The neutralization electron source is processed and assembled,and its emission performance is tested.The main contents of this paper are as follows:（1）Simulation design of neutralization electron source.The physical model of La B6-Si composite array cathode consistent with the preparation process is established by using opera-3D simulation software.However,due to the large difference between the structural scale of grid and cathode array,it is difficult to realize the effective simulation of cathode emission surface.Therefore,the actually prepared La B6-Si FEA and emission cathode plane are treated equally,The simulation of the grid is emphatically analyzed,and the effects of different shapes and types of grid on the field emission performance are studied,as well as the effects of the structural parameters of the grid,including the cathode grid spacing,the inclination rate of the inner wall of the grid and the grid potential on the electron emission performance.Preliminary preparations are made for the subsequent structural assembly and testing of neutralization electron source.（2）Preparation and research of field emission cathode.Lanthanum hexaboride is an excellent cathode electron emission material.It has the advantages of good conductivity,low escape work（2.6 e V）,high melting point and good physicochemical stability.In this paper,La B6-Si composite array cathode is prepared by nanosphere lithography combined with semiconductor micro nano processing,which greatly improves the stability of cathode emission and the integration of the array.Nanosphere lithography is a low-cost preparation method of micro nano array structure that can realize mass production.The integration degree of cathode array used for preparation can reach 10~7units/cm~2.Compared with optical lithography and electron beam lithography,it reduces the cost of preparation process.（3）Emission performance test of neutralizing electron source.According to the simulation results,the part structure is designed and processed,and then the parts of the neutralization electron source are pretreated.The designed cathode and grid are assembled,and the test device and test circuit are built by Under 1×10-5 pa,the emission performance and stability are tested.The grid voltage is less than 500 V,the emission current of 0.8 m A can be obtained,the overall anode voltage can be less than 2000 V,and the component power consumption is less than 2 W,which meets the design requirements of neutralization electron source. |
