Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements

ORAL

Abstract

Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like $N_2$-$O_2$ (4:1) admixtures. A maximum in the O-atom concentration of 9.1 10$^{20}$ m$^{-3}$ was found at admixtures of 0.35 vol\%, while the N-atom concentration exhibits a maximum of 5.7 10$^{19}$ m$^{-3}$ at 0.1 vol\%.

*The authors acknowledge support by the UK EPSRC through the grants EP/H003797/1 and EP/K018388/1

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Authors

  • Timo Gans

    • York Plasma Institute, University of York, UK
    • York Plasma Institute, Department of Physics, University of York, York, YO10 5DD, UK
    • University of York
    • York Plasma Institute, University of York, Heslington York, UK

  • D. O'Connell

    • York Plasma Institute, University of York, UK

  • N. de Oliveira

    • Synchrotron Soleil, France

  • D. Joyeux

    • Synchrotron Soleil, France

  • L. Nahon

    • Synchrotron Soleil, France

  • J.P. Booth

    • Laboratoire de Physique des Plasmas-CNRS, Ecole Polytechnique, France

  • Timo Gans

    • York Plasma Institute, University of York, UK
    • York Plasma Institute, Department of Physics, University of York, York, YO10 5DD, UK
    • University of York
    • York Plasma Institute, University of York, Heslington York, UK