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P: Fachverband Plasmaphysik
P 19: Poster II
P 19.33: Poster
Thursday, March 31, 2022, 16:00–17:30, P
Ion-induced secondary electron emission of metal surfaces analysed in an ion beam experiment — •Rahel Buschhaus and Achim von Keudell — Experimentalphysik II, Ruhr-Universität Bochum, Deutschland
Electron emission of surfaces upon ion impact is one of the most fundamental plasma-surface-interaction. Many experimental and theoretical approaches address secondary electron emission coefficient determination (SEEC; amount of released electrons per incident ion) in literature. This determination may remain rather indirect though, because the process of ion-induced electron emission occurs often not isolated from all other plasma-surface-interactions. Using beam experiments avoids this complication and allows a precise electron yield determination. Target conditions in plasmas strongly affect electron emission of the target and thus have an impact on the discharge itself. However, data of oxidized and nitrided targets, as they would appear in any reactive plasma discharge, are very sparse and may even contain significant systematic errors, because they were often measured based on global modeling of the complex behavior of plasma discharges. SEECs of different metal foils such as Cu or Ni with various surface conditions are investigated in a beam experiment. Foils are exposed to beams of Ar+ with Eion=500 eV - 2 keV and electron yields are determined precisely. A model for the electron emission is presented to explain the data.