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S. Haslinger, J. Hell, J. Laimer:
"Investigation of an atmospheric pressure radio-frequency capacitive plasma jet";
Poster: Junior Scientist Conference 2006, TU Wien; 19.04.2006 - 21.04.2006.

We have constructed a large area atmospheric pressure plasma jet (LAAPPJ) composed of two planar electrodes with an area 38cm² at a distance of 2.5 mm. The LAAPPJ was operated with helium and argon at a gasflowrate of 1.5 mmol/s. The electrical properties of the discharge were studied by measuring the voltage and the discharge current simultaneously. Pictures of the discharge were taken with a digital camera.
Usually plasma sources operated at atmospheric pressure are based on arc discharges and produce thermal plasmas with temperatures well above a few thousand K. The generated atmospheric pressure glow discharge operates at a gas-kinetic temperature near room temperature. However, large area glow discharges at atmospheric pressure were considered to be rather unstable. We found two stable discharge modes, namely the α- and the γ-mode. At rf input powers of 50-400 W an α -discharge can be sustained, at higher powers a transition to a γ-discharge takes place. Both modes are considered to be interesting, targeting diagnostics and application, especially sterilisation, etching, deposition, surface modification and decontamination. The properties of this plasma make this atmospheric pressure plasma source an attractive alternative to vacuum plasmas that have been used in material processing applications.

* S. Haslinger, graduand at the Institut für Allgemeine Physik, Vienna University of Technology, Wiedner Hauptstraße 8-10 A-1040 Wien, Austria

+ ao Univ. Prof. Dr. J. Laimer, part of the Surface and Plasma Technology Research Group at the Institut für Allgemeine Physik and faculty mentor of S. Haslinger