Cyclotron maser oscillator experiments in a periodically loaded waveguide

The periodic-waveguide cyclotron maser is a device in which orbiting, nonrelativistic electrons interact with traveling waves in a metallic, periodically loaded waveguide. In this paper, we describe a table-top oscillator experiment that operates in the microwave regime (9.4 GHz) with a low-energy (8 keV), low-current (0.2 A) electron beam pulse (1 ms pulse width). The frequency modulation (chirping) observed is used in the determination of cyclotron resonance condition for this interaction. The results show that the cyclotron interaction occurs with a backward-propagating wave in the periodically loaded waveguide. Microwave power of /spl ges/0.3 kW and efficiency of /spl ges/20% are measured by an external loading of the oscillator.<
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