Kiel 2004 – scientific programme
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P: Plasmaphysik
P 16: Niedertemperaturplasmen Plasmatechnologie III
P 16.2: Fachvortrag
Wednesday, March 10, 2004, 15:45–16:05, H\"orsaal H
Non-thermal plasmas as sterilisation- and coating technique — •Christian Schrader and Karl-Heinz Gericke — Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer Strasse 10, D-38106 Braunschweig
Non-thermal plasma processing at atmospheric pressure has received growing interest. Recently, micro-structured electrode (MSE) arrays were introduced as alternative atmospheric pressure plasma sources. They consist of planar and parallel electrodes with geometric characteristics in the µm-range manufactured by means of modern micro machining and galvanic techniques. Our experimental setup consists of a MSE array coupled to a RF-generator unit with a special probe in order to measure voltage, current and phase angle of the system. A planar electrode at a distance of 2 mm is biased with different acceleration potentials in order to bridge the gap between plasma source and substrate. As an example the usage of the plasma source to sterilise UV- or thermo resistant spores placed on food-packaging materials is demonstrated. Motion of the particles is drift controlled, because amplitudes of electrons as well as ions exceed d/2 of the electrode gap d (70 µm). To describe the behaviour of the charged particles in the RF field (frequency ω) we use the DC Townsend breakdown theory. The ion amplitudes z0 were calculated by:
z0=eE0/mω √ω2+νc2
This equation gives the extreme values derived from the solution of the equation of motion including the pressure dependent Lorentz collisional term νc in order to account for friction.