Hannover 2016 – scientific programme

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P: Fachverband Plasmaphysik

P 27: Low Temperature Plasmas III

P 27.4: Talk

Friday, March 4, 2016, 11:45–12:00, b305

Chemistry of neutral and charged species in the effluent of the micro atmospheric pressure plasma jet in water-helium admixture — •Gert Willems, Achim von Keudell, and Jan Benedikt — Experimental Physik II, Ruhr-Universität Bochum, Germany

A thorough understanding and good control of produced neutral and charged species by cold atmospheric plasmas is essential for potential environmental and/or bio-medical applications. In this respect, mass spectrometry of these plasmas can provide absolute number densities of stable and reactive species and relative trends of charged species. Thereby giving valuable insights into the reaction chemistry. In this study we use the COST reference micro plasma jet (µ-APPJ), a radio-frequency capacitively coupled plasma source with 1 mm electrode distance, which has been operated in helium-water vapour mixture and has been studied as a potential source of hydroxyl radicals and hydrogen peroxide molecules. The water vapour concentration was up to 1.2%. The measurements of hydrogen peroxide and hydroxyl radicals from atmospheric plasma, as measured using MB-MS, will be presented. Their dependency on water vapour concentration in the carrier gas as well as distance to target have been investigated. The measured density is between 5E-13 cm-3 (2.4ppm) and 1.5E-14 cm-3 (7.2ppm) for both hydrogen peroxide molecules and hydroxyl radicals. The achieved results are in good agreement with data from Cavity-Ringdown laser absorption spectroscopy.