Simulation and experiment on relativistic Klystron Amplifier driven by strong input power

This paper presents proposes a method of improving the input power to inhibit parasitic oscillations. Particle-in-cell simulation results indicate that the relativistic klystron amplifier driven by strong input power is a potential device to attain high stability, high efficiency, wide bandwidth, and frequency and phase locking. An electron beam of 200 keV, 1k A is used in simulation. Under the condition of 5 MW external power feeding, about 0.9 kA modulation current is obtained with only one cavity. The output microwave power is 70 MW, with 5% bandwidth and 40% efficiency. The experiment is carried out at SPG200 accelerator, the typical diode voltage and current of which are 200kV and 1 kA, respectively. An S band klystron with peak power about 4 MW is used as inputs.