Accurate Simulation And Anslysis Of Traveling Wave Tube Electron Gun

Microwave tube has been rapid development and wide applicationg,since it came into force.Traveling wave tube accounted for more than half of all microwave tube sales after the first line of wave tube developed in 1943.Electron gun,as an important part of traveling wave tube,who plays a decisive role in the performance of the whole tube.There always is significantly inconsistent between the simulation results and the actual working conditions.Because many designers have always adopted default settings.So how to make the simulation results more better represent the actual working situation of tube,which is very crucial,which is also the focus of this paper.In this paper,the important electrical parameters of the electron gun,including the cathode material property,mesh size and virtual anode position,are mainly analyzed and studied.The parameters are simulated on axisymmetric electron gun model and gridded electron gun model.By analyzing large amounts of simulation data,it is conclude that,the work function and temperature have a great influence on the cathode current,the temperature is selected when the cathode emission current is in the steady state according to the actual measured work function value;the larger grid value is selected to improve the simulation efficience in the case of guaranteeing convergence;the virtual anode position seriously affects the emission current,which is selected when the cathode emission current is at the extreme point by comparing.To verify the rationality of method,it simulates other guns with different diversion coefficient.In this paper,the other important parameters,such as: finite element order,local symmetry calculation,adaptive calculation and solving dimension are also studied.The parameters are simulated on axisymmetric electron gun model and gridded electron gun model.It is concluded that by analyzing simulation data detailedly,select the finite element linear interpolation,1/4 local symmetry calculation,non-adaptive and three-dimensional calculation when simulating electron gun accurately.Through studying the parameters,the calculation results,calculating time and computer resources can be more better coordinated to improve simulation efficiency in case of ensuring the accuracy.This paper presents the parameter scheme.Through two gridded electron gun models and two axismmetric electron gun models,the difference between the exact value and the default value is displayed according to the proposed method,which indicates the importance of the proposed method.The proposed method provides a convenient and effective simulation process for the industry,reducing the optimization period of the electron gun and avoiding unnecessary waste of resources such as manpower and materials.