Research On The Electron-Optical System Of High Peak Power Multi-Beam Klystron

High peak power multi-beam klystron is a new type of microwave electron tube, which is developed on the basis of single-beam klystron and basic-mode multi-beam klystron. It works on higher-order mode of cylindrical cavity or basic mode or higher-order mode of ring cavity. The electric field of working mode determines that the electron beams should be distributed on a circle with big-radius, thus the power-level of the tube increases. But on the other hand, the influence of the transverse field on electron beams increases too. To decrease transverse field and further to obtain good focusing electron beams, the focusing field must be symmetric with each beam's main axis, but it is not easy.Since the study of electron-optical system of high peak power multi-beam klystron is a 3D problem, the 3D electron-optical simulation software is absolutely necessary. But it is not economical to simulate the system with 3D software barely. Therefore, an effective and precise CAD method must be developed.With the goal of solving the problems above and designing an eligible electron-optical system, plenty of simulations and analyses are carried out about the electron-optical system of an S-band 50-MW multi-beam klystron. A method transiting the system from 2D rotational-symmetry condition to 3D non-rotational-symmetry condition is used in the design. Single gun for the multi-beam gun is designed firstly with scaling method, and then the focusing system is designed approximately. The electron trajectories are simulated with 2D electron-optical software EGUN on condition that the single gun is located at the main axis of focusing system. After simulating and optimizing the system until the...