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P: Fachverband Plasmaphysik
P 2: Magnetic Confinement, Plasma-Wall Interaction & Helmholtz Graduate School I
P 2.4: Vortrag
Montag, 30. August 2021, 12:10–12:25, H6
Ion-induced secondary electron emission of metal surfaces analysed in an ion beam experiment — •Rahel Buschhaus, Marina Prenzel, and Achim von Keudell — Experimentalphysik II, Ruhr-Universität Bochum
Electron emission from surfaces during ion impact is one of the most fundamental plasma-surface-interaction. The surface conditions in plasmas strongly affect this electron emission and thus have an impact on the discharge itself. However, data of oxidized targets for instance, as they would appear in any reactive plasma discharge, are very spare and may even contain significant systematic errors, because they were often measured by modeling the complex behavior of plasma discharges. Many experimental and theoretical approaches address secondary electron emission coefficient determination (SEEC; amount of released electrons per incident ion) in literature [1,2]. However, this determination may remain rather indirect, because the process of ion-induced electron emission overlaps with other plasma-surface-interactions. Using beam experiments avoids this complication and allows a precise electron yield determination. SEECs of clean, untreated (air-exposed) and intentionally oxidized Cu and Ni foils are investigated in a beam experiment. Here, metal foils and oxidized foils are exposed to beams of Ar+ with Eion=200 eV - 10 keV and electron yields are determined precisely. A model for the electron emission is presented to explain the data. Surface conditions were analyzed by ex-situ XPS measurements. [1] D. Depla et al. J.Phys.D:Appl.Phys.,2008 [2] M. Daksha et al. J.Phys.D:Appl.Phys., 2016