Two-cavity wide-gap klystron amplifier driven by relativistic backward-wave oscillator

An inductively-loaded two-cavity wide-gap klystron amplifier (WKA) with high power injection driven by a relativistic backward wave oscillator (RBWO) is studied theoretically and experimentally for solving the problem of power insufficiency of existing seed sources. The electric power of the amplifier and oscillator is supplied by a single accelerator capable of producing dual electron beams. The main switch is electrically triggered to stabilize the diode voltage and the frequency of the RBWO. In the experiments, the frequency and phase of the WKA are locked by the RBWO. The relative phase difference of the applied microwave devices is locked within 16 in a single shot, and a phase jitter of 11 is obtained within a series of 4 shots with a duration of about 40 ns. Under a diode voltage of 530 kV and injection power of about 22 MW, an output power of 230 MW is achieved from the RBWO-WKA system with a conversion efficiency of approximately 11% and power gain of approximately 10 dB.