A Multiobjective Optimization Design Tool for Traveling-Wave Tubes’ Electron Optics System

The nondominated sorting genetic algorithm II and the electron optics simulator were combined to form a multiobjective optimization design tool for electron optics systems of traveling-wave tubes. After determining the objective functions that vary with the macroscopic electrical parameters that need to optimize the electron optics system, the optimization tool is capable of obtaining the optimal solution set automatically. Then, the microscopic electron trajectories of the individuals in the optimal solution set are analyzed to get the final scheme. In the collector optimization, the maximum collector efficiency and the minimum back-streaming current are used as optimization goals. While for the demonstrated electron gun, the maximum waist position is set to be the optimization goal, together with constraints of emitting current and beam waist radius. After analyzing the energy density distribution on the collector inner surface or the laminar flow of the electron gun, the final scheme is determined from the optimal solution set.