Periodic permanent-magnet focusing system capable of regulating magnetic field and klystron

Abstract

The invention provides a periodic permanent-magnet focusing system capable of regulating magnetic field and a klystron. The periodic permanent-magnet focusing system comprises an electromagnetic coil adjustment device and a periodic permanent-magnet focusing device, wherein the electromagnetic coil adjustment device comprises N coils and a support shell, the N coils are arranged in an accommodating cavity of the support shell, and an outer-side coil pole shoe of the electromagnetic coil adjustment device is fixedly connected with one end of the periodic permanent-magnet focusing device. The electromagnetic coil adjustment device is arranged on a transition region of the klystron, so that an incident angle of an electron beam is matched with a periodic permanent-magnet focusing magnetic field, and the defect that the magnetic field of a traditional permanent-magnet focusing system cannot be regulated or is not convenient to regulate is overcome; a current value of the coil can be independently adjusted, the magnetic field is more flexible in regulation, and the regulation accuracy is higher; the klystron is provided with the periodic permanent-magnet focusing system and is high in beam quality; and the electromagnetic coil adjustment device is further arranged at the rear end of the periodic permanent-magnet focusing device, the transmission state of the electron beam can be adjusted, and relatively high electron beam transmission passing rate can be acquired.

Description

technical field [0001] The invention relates to the technical field of vacuum electronic devices, in particular to a periodic permanent magnet focusing system and a klystron with an adjustable magnetic field. Background technique [0002] The klystron is a device that converts kinetic energy into high-frequency microwave energy through electron injection as a transduction medium. In the klystron, after the electron beam is emitted from the cathode, it is transmitted to the anode by the force of the electric field, and is compressed and shaped by the electric field formed by the focusing electrode, the cathode and the anode. When the electron beam diameter is compressed to a certain extent, due to the effect of space charge force, the electron beam will diverge radially. Therefore, it is necessary to take restraint measures for electronic injection. In the klystron, the function of the focusing system is to realize electron beam forming and electron beam shape retention, wh...

AI Technical Summary

Problems solved by technology

[0006] (1) After the periodic permanent magnet focusing system is formed, its magnetic field distribution is not easy to adjust. If the focusing electron injection effect is poor, the focusing system needs to be replaced;

[0007] (2) The magnetic field distribution in the transition area is related to the matching state of the electron beam and the focusing system. Generally, in the working state, a small magnetic block is pasted near the magnetic screen at the end of the electron gun to adjust the magnetic field in this area, which is difficult to adjust;

[0008] (3) Adjusting the magnetic field by pasting a magnetic sheet on the focusing system can only be used in klystrons working under low voltage. When the working voltage is too high, it cannot be adjusted in consideration of personal safety

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