An X-band gigawatt amplifier

In an X-band Cerenkov amplifier driven by a 0.8-MeV 6-kA electron beam, a gigawatt-level of power radiated in a Gaussian pattern in a 70-ns pulse duration has been demonstrated. The coherence of the output radiation is provided by dividing the oversized interaction space into separate sections with different azimuthal symmetry that couples only with the electron beam. A large gain of 47 dB and an efficiency of 23% are obtained using a regenerative amplification of a backward-wave amplifier (BWA) that produce a modulation of the electron beam. The efficiency of this device is 27% when the BWA-modulator operates in the regime of auto oscillations.