Gyro-BWO experiments using a helical interaction waveguide

W. He, K. Ronald, A.R. Young, A.W. Cross, A.D.R. Phelps, C.G. Whyte, E.G. Rafferty, J. Thomson, C.W. Robertson, David Speirs, S.V. Samsonov, V.L. Bratman, G.G. Denisov

Research output: Contribution to journalArticle

77 Citations (Scopus)

Abstract

A helically corrugated waveguide was used for a gyrotron backward-wave oscillator (gyro-BWO) experiment. A thermionic cathode was used to produce an electron beam of 90-215 keV in energy, 2-3 A in current, and pitch alpha of up to 1.6. The oscillator achieved high-efficiency frequency-tunable operation. At a fixed beam voltage of 185 kV and a current of 2 A, the output frequency was tuned by adjusting the magnetic field in the interaction cavity. A maximum power of 62 kW and a 3-dB frequency-tuning band of 8.0-9.5 GHz (17% relative tuning range) with a maximum electronic efficiency of 16.5% were measured. In addition, the interaction frequency could be tuned by varying the electron beam energy. At a fixed cavity magnetic field of 0.195 T, the output frequency and power from the gyro-BWO were measured as a function of tuning electron beam energy while the beam current was maintained at 2.5 A. A 3-dB relative frequency tuning range of 8% was measured when the electron beam voltage was changed from 215 to 110 kV.
Original languageEnglish
Pages (from-to)839-844
Number of pages5
JournalIEEE Transactions on Electron Devices
Volume52
Issue number5
DOIs
Publication statusPublished - May 2005

Keywords

  • backward wave oscillators
  • gyrotrons
  • helical waveguides
  • thermionic cathodes
  • plasma
  • cyclotron-resonance maser
  • high-power microwave devices

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