The Study And Design Of Magnetic Field In Transition Area For Traveling-wave Tubes

Designing the magnetic field is a focus of the traveling wave tube design. There is a slowly varying magnetic field transition region between the electron gun and the interaction region. The process of electron beam through the transition zone is the electron gun parameters to match the interaction parameters. It shows that the quality of this match has a great influence on the quality of the interaction of the electron beam in the region, However, due to the transition zone is more complex, theoretical analysis and experimental measurements are more difficult, There is no complete theoretical formula can be used, the need to manually adjust a little bit, slow design. In the interaction region to gather design then focus area between the polar regions is a major difficulty, Although there are some theories to follow, but a different state of the electron beam traveling wave tube different, Drift region of the magnetic field needed is very different, Ideally through the electronic high-frequency field effect after the classification were collected by speed, so that kinetic energy of electrons hit the low-potential electrode, When the kinetic energy of the electrons hit the small high potential electrode, so that electrons reach the respective electrode surface speed close to zero. This collector is almost no energy. Good design for these two magnetic transition zone focus and energy to collect the electron beam of great significance Design and research of this paper the use of microwave tube simulation software packages MTSS transition zone of the magnetic field. This paper includes the following aspects:1. Simply introduces the basic theory of the electron optical system.Including the basic theory of the electron gun and collector, and then follow the theory to guide the design of the electron gun and paper collector, Finally, introducing the existing theory and the importance of transition zone between the electron gun magnetic field region and the interaction region and the refocusing interaction region.2. Using simulation software suite MTSS design electron gun with laminar flow, using MFS module generates a magnetic field, the magnetic field of a constant peak studies, might affect the peak magnetic transition region, the magnetic field of the magnetic structure size and period of the electron beam focus, etc.3. By analyzing the electron beam generated by the interaction region information, and then add the appropriate focus area field, and then optimize the collector, to maximize efficiency. The main impact of the cycle and the peak of the magnetic field on the electron beam performance, the difficulty is how to produce better electron injection and how to produce different peak magnetic field.Finally, the choice of the magnetic field and the peak period is given a certain range, which is designed to reduce the magnetic field cycle has a certain significance.