Charge-exchange neutral hydrogen measurements in TFTR using Pd-MOS microsensors

R. Bastasz, S. J. Kilpatrick, D. N. Ruzic

Research output: Contribution to journalArticlepeer-review


An array of Pd-metal-oxide semiconductor (Pd-MOS) diodes has been used to monitor the fluence and energy of charge-exchange neutral hydrogen isotopes striking the wall of the Tokamak Fusion Test Reactor (TFTR). The array was positioned 4 cm behind the graphite-tiled wall at the toroidal midplane and exposed to several hundred plasma discharges. Hydrogen isotopes striking the Pd-MOS diodes were detected by measuring the leakage current, which is affected by the presence of these species at the Pd/SiO2 interface. It was found that the midplane flux strongly increased for neutral-beam heated plasmas and correlated with co-injected neutral beam power. The majority of the neutral flux was < 50 eV in energy but its energy distribution extended to above 500 eV.

Original languageEnglish (US)
Pages (from-to)1038-1043
Number of pages6
JournalJournal of Nuclear Materials
Issue numberC
StatePublished - Dec 3 1990

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • General Materials Science
  • Nuclear Energy and Engineering


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