Diagnostics of an O₂–He RF Atmospheric Plasma Discharge by Spectral Emission

In this paper optical emission spectroscopy (OES) is used as a Diagnostic technique for the measurement of atomic and molecular spectral emissions generated using a helium rf industrial atmospheric plasma jet system. The OES of neutral atomic spectral lines and molecular bands are investigated over a range of plasma process parameters. Wavelength resolve optical emission profiles suggest that the emission of helium’s spectral lines shows that the high energy electrons have a larger influence than helium metastables on the overall spectral emission. Furthermore, the experimental data indicates that the use of high helium flow rates, in any confined open air plasma discharge, limits the significance of air impurities, e.g., nitrogen, for the creation and sustainability of plasma discharges in helium–oxygen gas chemistry.