Experimental operation of a gyro-travelling wave amplifier with a helically corrugated interaction region is presented. Two thermionic cathode electron guns in Pierce-type geometries were used to generate rectilinear electron beams of 1 μs pulse duration. One diode was operated at 185 keV energy with a current of 7.5 A and the other was operated with an applied potential of 115 kV producing a current of 18 A. Transverse velocity was imparted to the electron beam in a 'kicker'. The electron beam acquired a transverse velocity typically with a pitch factor of between 1 and 1.2. The resulting electron beam described a helical, axis-encircling trajectory. The coupling between the second harmonic cyclotron mode of the gyrating electron beam and the radiation field occurred in the region of near infinite phase velocity over a broad frequency band using a cylindrical waveguide with a helical corrugation on its internal surface. With a beam energy of 185 keV, the amplifier achieved a maximum output power of 220 kW, saturated gain of 24 dB, saturated bandwidth of 8.4 to 10.4 GHz (21% relative bandwidth) and an efficiency of 16%. With a beam energy of 115 keV, the amplifier achieved a maximum output power of 160 kW and an efficiency of 8%.
|Title of host publication||Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electionics|
|Place of Publication||New Jersey, USA|
|Number of pages||1|
|Publication status||Published - 2004|
- experimental operation
- gyro-travelling wave amplifier
- thermionic cathode electron guns
- electron beams
- pulse duration
Phelps, A. D. R., Ronald, K., He, W., Young, A. R., Rafferty, E. G., Cross, A. W., ... IEEE (2004). Results from thermionic cathode gyro-twa experiments. In Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electionics (pp. 273-274). New Jersey, USA: IEEE.