Results from thermionic cathode gyro-twa experiments

A.D.R. Phelps, K. Ronald, W. He, A.R. Young, E.G. Rafferty, A.W. Cross, C.G. Whyte, Jamie Thomson, C.W. Robertson, IEEE

Research output: Chapter in Book/Report/Conference proceedingChapter

1 Citation (Scopus)


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%.
Original languageEnglish
Title of host publicationConference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electionics
Place of PublicationNew Jersey, USA
Number of pages1
ISBN (Print)0780384903
Publication statusPublished - 2004


  • experimental operation
  • gyro-travelling wave amplifier
  • thermionic cathode electron guns
  • electron beams
  • pulse duration
  • diode
  • energy


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