A Simulation Method to Determine the Assembly Distance between Cathode and Heater of Electron Gun

The assembly distance between cathode and heater has significant influence on the performance of electron gun of traveling wave tubes. This paper presents a simulation method to accurately determine this assembly distance. The simulation method uses ANSYS to simulate the working state of electron gun, and transfers the thermally deformed cathode and heater models into CST through the ANSYS geometry processing module SpaceClaim. Use the contact judgment function of CST to gradually move the heater to contact the cathode to measure the distance between cathode and heater. Adjust the model on the basis of measuring results and continue simulation process until the assembly distance which satisfies the assembly tolerance rate is obtained. This method can accurately measure the distance between cathode and heater after deformation, avoid damage of electron gun under working condition and effectively guide the assembly process of electron gun.