Experimental CARM operation at 150 Hz PRF

Summary form only given, as follows. Successful operation of the Cyclotron Autoresonance Maser experiment at Strathclyde University has been achieved, at a pulse repetition frequency (PRF) of 150 Hz. Microwave pulse measurements are presented demonstrating second harmonic operation in a TE/sub 21/ cylindrical mode, in agreement with numerical predictions. Measurements of the power and oscillation frequency at 14.2 GHz, and of the radial and azimuthal far-field mode patterns are described. A stacked Blumlein pulsed voltage source provided repetitive 300 kV, 100 ns electron pulses from a velvet cathode. CARM oscillation was achieved in a cavity magnetic field of 0.21 Tesla, with a Doppler frequency upshift of 6.8 GHz from the 2nd harmonic of the cyclotron frequency. A self-consistent numerical model of electron beam trajectories, developed at Strathclyde, was used to predict device parameters in the design of the axial-beam electron source, helical-beam kicker and Bragg interaction cavity. Numerical calculations of electron beam parameters are presented, showing close agreement with electron beam and microwave diagnostic measurements.