Measurements of RE wave-electron interactions in a low frequency (150 MHz) crossed-field amplifier

Summary form only given. A low-frequency (100-200-MHz), low-power (<400-W-input) crossed-field amplifier (CFA) has been constructed in order to measure the interaction of electrons with an RF wave during amplification. The physically large device (40-cm long, 25-cm wide, 2-4-cm anode-to-cathode spacing) allows the insertion of RF probes to measure the local RF fields and an electron energy analyzer to measure the electron energy distribution. The magnetic field (up to 80 G) is provided by a set of 1-m-diameter Helmholtz coils. The slow-wave circuit consists of a serpentine copper line on a Teflon dielectric and copper ground plane. The slow-wave wavelength is 6 cm at 150 MHz. The electrons are provided by heated tungsten filaments, and the electrons are then injected into the interaction region. This device then operates with a beam injected source. The cathode voltage is typically -1.2 kV. Gains as high as 6 dB have been demonstrated for low input power (10 W). Lower gain (2-3 dB) was obtained for higher input powers (100 W). Power limitations are due to the limitations of the electron beam source