Cyclotron resonance maser experiments in a bifilar helical waveguide

Oscillator and amplifier cyclotron-resonance-maser (CRM) experiments in a spiral bifilar waveguide are presented in this paper. The slow-wave CRM device employs a low-energy low-current electron beam (2-12 keV, approximately 0.5 A). The pitch angle of the helical waveguide is relatively small; hence, the phase velocity in this waveguide, V(ph) congruent with0.8c (where c is the speed of light), is much faster than the axial velocity of the electrons, V(ez)2%). The wide tunable range of this CRM device due to the nondispersive bifilar helix is discussed.