Berlin 2005 – scientific programme

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P: Plasmaphysik

P 14: Poster: Niedertemperaturplasmen / Plasmatechnologie 6, Diagnostik 4

P 14.17: Poster

Saturday, March 5, 2005, 14:45–16:45, Poster HU

Absolute Atomic Oxygen Density Measurements in an RF Excited Atmospheric Pressure Plasma Jet (APPJ) by Two-Photon Laser-Induced Fluorescence Spectroscopy (TALIF) — •K. Niemi, S. Reuter, V. Schulz-von der Gathen, and H. F. Döbele — Universität Duisburg-Essen, Fachbereich Physik, Universitätsstr. 5, 45117 Essen

The APPJ operated with a high helium flux and small molecular admixtures such as oxygen, fluorine or hydrogen contains a homogeneous plasma generated between concentric electrodes by capacitively coupled RF power at 13.56 MHz [Selwyn et al. 1998 IEEE Trans. Plasma Sci. 26 1685]. The jet effluent leaving the discharge through a ring-shaped nozzle contains high concentrations of radicals at a low temperature – the key-property for a variety of applications like etching, coating, sterilization and decontamination of temperature sensitive surfaces and possibly in-situ medical treatment. We report on quantitative atomic oxygen density measurements in the effluent of an APPJ by TALIF using a novel calibration scheme with xenon. Near the nozzle atomic oxygen densities up to 3×10¹⁵ cm⁻³ and a temperature of 80 ^∘C were measured at a helium flux of 2 m³/h, an oxygen admixture of 0.5% and an RF-power of 150 W. The atomic density decreases by two orders of magnitude along a distance of ∼10 cm from the nozzle while remaining concentrated on axis.

This work was supported by the ’Ministerium für Wissenschaft und Forschung des Landes Nordrhein-Westfalen’.