Cathode and anode optimization in a virtual cathode oscillator

Y. Chen, J. Mankowski, J. Walter, M. Kristiansen, R. Gale

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


We are fabricating and testing several different types of cathodes for the same vircator driven by a single shot Marx generator and pulse forming line (300 kV, 60 ns, 30 Ω). The cathodes types, each with an emitting area of ∼32 cm2, include the original velvet with a new geometry, carbon fiber, pin-array, and an array of all metal cathodes. The metal cathodes are made from aluminum and oxygen free copper fashioned to similar geometries with either a chemical etch or a CNC machining process. The vircator is tested with all of these cathodes using both polarity configurations and evaluated for beam voltage, current density, microwave output, and single shot lifetime. In addition to the cathode testing, several stainless steel and tungsten anode meshes with varying transparencies (50% - 80%) are evaluated. The construction and testing of an anode fashioned from Tantalum (70% transparency) is also discussed. Electron beam uniformity of the metal cathodes is investigated with the emitted electron beam current-density distribution evaluated in both time and space. Optimization of output power using resonant effects is also examined.

Original languageEnglish
Pages (from-to)1037-1044
Number of pages8
JournalIEEE Transactions on Dielectrics and Electrical Insulation
Issue number4
StatePublished - Aug 2007


  • All metal cathode
  • Carbon fiber
  • Electron beam uniformity
  • HPM
  • Marx generator
  • Pin array
  • Resonant effects
  • Transparency
  • Virtual cathode oscillator


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