Killing of bacterial spores contained in a paper envelope by a microwave plasma torch

Spencer P. Kuo, Olga Tarasenko, S. Popovic, Kalle Levon

Research output: Contribution to journalArticlepeer-review


The air plasma effluent of an arc-seed microwave torch is used to kill bacterial spores contained inside an envelope. The torch is operated at a 60-Hz periodic mode (with about 40% duty cycle) and runs stably at a low airflow rate (e.g., 0.393 l/s). The images of plasma torch plumes show that the arc loop of the discharge prolongs from the electrodes by nearly 3 cm and microwave energizes the charge particles along the arc loop considerably. The emission spectroscopy of the torch indicates that the plasma effluent contains an abundance of reactive atomic oxygen. Bacillus cereus is chosen for the biological agent in the decontamination experiment. The experiment and the decontamination efficacy of this torch are presented. The averaged temperature inside the envelope is measured to be less than 40 °C, thus ruling out the thermal decontamination mechanism.

Original languageEnglish (US)
Pages (from-to)1275-1280
Number of pages6
JournalIEEE Transactions on Plasma Science
Issue number4 II
StatePublished - Aug 2006


  • Biological warfare agents
  • Decontamination
  • Microwave plasma torch (MPT)
  • Oxidation
  • Spores

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Condensed Matter Physics


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