Pseudospark-based electron beam and Cherenkov maser experiments

Detailed experimental results from the first free-electron maser experiment to use a pseudospark-based electron beam are presented in this paper. These include the design and realization of a pseudospark-based electron beam source and Cherenkov maser experiment. A pulsed, 70-80 kV, 10 A electron beam was obtained from the hollow cathode discharge phase of an 8-gap pseudospark (PS) discharge. The beam was used to produce coherent microwave radiation via a Cherenkov interaction between the electron beam and the TM01 mode of a 60-cm long alumina-lined waveguide. A gain of 29+/-3 dB was measured and an output power of 2+/-0.2 kW in the frequency range 25.5-28.6 GHz. Results from numerical simulations of the Cherenkov amplification are also presented and found to be consistent with the experimental results.