Bochum 2015 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 6: Poster Session - Diagnostics

P 6.12: Poster

Montag, 2. März 2015, 16:30–18:30, Foyer Audimax

Absolute densities of OH and O radicals in the effluent of a He/H₂O micro-scaled atmospheric pressure plasma jet — •Simon Schneider¹, Daniel Schröder¹, Gert Willems¹, Volker Schulz-von der Gathen¹, Andrea Pajdarova², Jaroslav Vlcek², and Jan Benedikt¹ — ¹Ruhr-Universität, Bochum, Deutschland — ²University of West Bohemia, Pilzen, Czech Republic

Cold atmospheric plasma (CAP) sources operated in helium with small admixtures of oxygen are known to be effective sources of reactive oxygen species (ROS), metastables, ions, or VUV and UV photons. It is well-known that microorganisms, like bacteria, can be inactivated by treatment of the effluent of these sources. The reaction chemistry and treatment of microorganisms are highly influenced by additional species resulting from common water impurities.

In this work, we present the measurement of hydroxyl radicals (OH) and atomic oxygen (O) in the effluent of a micro-scaled atmospheric pressure plasma jet (µ-APPJ) operated in helium with small admixtures of water vapor (< 6150 ppm). OH is measured by cavity ring-down spectroscopy (CRDS) and O is measured by two-photon absorption laser induced fluorescence spectroscopy (TALIF). The maximum OH density is 9×10¹³ cm⁻³ and the maximum O density is 1.3×10¹³ cm⁻³. Furthermore, a modified version of the µ-APPJ which is able to separate effects of particle and photon components in the effluent of the µ-APPJ, is introduced. Due to the separation, the influence of photons on the particle species and their reactions can be detected.