Mainz 2022 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 4: Low Pressure Plasmas II / Laser Plasmas II
P 4.2: Vortrag
Montag, 28. März 2022, 16:15–16:30, P-H11
Toroidal electron beam source for electron-induced processes at atmospheric pressure — •Lars Dincklage1, Burkhard Zimmermann1, Gösta Mattausch1, and Ronny Brandenburg2,3 — 1Fraunhofer Institute for Org. Electr., EB and Plasma Technol. FEP, Dresden, Germany — 2Leibniz-Institute for Plasma Science and Technology, Greifswald, Germany — 3University of Rostock, Germany
Accelerated electrons can be utilized to induce chemical reactions in gases. A toroidal electron beam (EB) source has been developed for optimum treatment of fluids in tubes as well as to generate EB-sustained atmospheric plasmas for plasma-chemical conversion processes. Electrons are created at a cooled metal cathode by the impact of ions from a low pressure wire anode (WA) plasma, accelerated in the electric field of the cathode and then emitted through an electron exit window (EEW) into the reaction space at the center of the torus. The energy of the electrons (typically 120 keV) and the EB current density at the EEW (about 100 µA/cm2) are controlled by the cathode potential and the electric properties of the WA discharge. In order to identify stable operation parameter windows, the WA discharge characteristics as well as its effect on the EB properties were investigated for helium and hydrogen. In case of operation at low pressure and with insufficient plasma current, limiting factors such as the contraction of the plasma and a high ignition voltage were determined. Whereas the first issue was handled by pulsing the plasma, the second was met by applying an external magnetic field. Furthermore, the current efficiency of the source was determined for different states of the metal cathode.