Influence of pressure increase on high-emission of Os-coated M-type cathode

Shengyi Yin, Zhen Peng, Yu Wang, Xinxin Wang

Research output: Contribution to journalArticlepeer-review


The influence of the pressure increase in a small multiple-beam klystron on the Os-coated M-type cathode, operating at a peak current density of 75 A/cm2, was experimentally studied. The relationship between the pressure and the emission current density was plotted. According to the plot, at 1.0×10-5 Pa, the current density was found to decrease by 1.96%; at 2.07×10-4 Pa, the current density dropped by 10%, and the cathode was found to be dying. The leakage-induced degradation possibly originated from two major factors: one is the oxidation of Ba+(a)into Ba2+ on the surface, inversely affecting the surface emission; the other is the de-activation of the emission sites by ion sputtering, resulted from the leaked-in gases, oxygen in particular. We concluded that the leakage accounts for the emission degradation.

Original languageEnglish (US)
Pages (from-to)224-227
Number of pages4
JournalZhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology
Issue number3
StatePublished - Mar 2013
Externally publishedYes


  • Electron emission
  • M-type cathode
  • Mechanism
  • Os film
  • Vacuum pressure

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry


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