PASOTRON amplifier experiments

Summary form only given. Experimental studies on a single-stage microwave amplifier based on Hughes´ plasma assisted, slow-wave oscillator technology (PASOTRON) are reported. The high-energy microwave amplifier employed in these studies utilizes a plasma-cathode electron-gun, and a plasma-filled slow-wave structure (SWS), to produce and propagate > 100-/spl mu/sec-long, 50-to-100 kV, 80-to-120-A electron-beam pulses without the use of any applied axial magnetic fields. The long-electron-beam pulses are coupled with a 120-/spl mu/sec-long, 10.1-GHz RF-drive signal provided by a 3-kW klystron. As the beam and the drive signal propagate through the SWS, amplification of the input-RF-drive signal is achieved. Amplified power levels of 3-to-7 kW have been achieved to date at maximum efficiencies of only 0.11%. However, measurements of the amplifier gain reveals signal level increases of 17 dB. Preliminary analysis of these results suggests that a frequency-dependent insertion loss of the present SWS when operated near the TM/sub 01/ mode´s upper cut-off frequency may be responsible for the amplifier´s low measured output power and efficiency, but high system gain.