RKA electron beam collection controlled by guiding magnetic field

An electron beam collection method in relativistic klystron amplifier(RKA) controlled by magnetic field is proposed. The influence of collection position on beam-wave conversion efficiency and stability of RKA is also analyzed. When the electron beam is collected at a proper position, the interaction between beam and microwave can be enhanced, and the space charge potential of electron beam and the number of reflected electrons can be reduced. An RKA has been improved with electron beam collection at the frequency of 2.85 GHz. When the electron beam voltage and current are 510 keV, 8.1 kA, the input power is 500 kW, and the guiding magnetic field is 1.5 T, an output power of 1.4 GW is obtained, and the corresponding efficiency and gain are 33.7% and 33.8 dB, respectively. When the beam col