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Hydrogen plasma induced photoelectron emission from metal surfaces

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Research report / Department of Physics, University of Jyväskylä
Authors
Laulainen, Janne
Date
2018
Discipline
Fysiikka

 
Low temperature hydrogen plasmas are strong sources of vacuum ultraviolet radiation. The properties of laboratory plasmas can be influenced by surface processes induced by photons with their energies exceeding the surface work function of the wall material. In this work, the plasma induced photoelectron emission has been studied with different ion sources. The emission depends on the mechanical design of the plasma device, plasma heating method and the discharge power (density). Parametric studies include the quantifying of the emission from different metal surfaces, commonly used as plasma facing materials in ion sources, as well as alkali metal covered surfaces. Experimental studies suggest that low temperature hydrogen plasma induced photoelectron emission from metal surfaces can reach an order of magnitude of 1 A per kW of plasma heating power. Furthermore, the emission can increase 2–3.5 times when the metal surface is coated with a thin layer of alkali metal reducing the work function. The free electrons produced by the photoelectron emission can influence various plasma processes and especially the plasma sheath structure, which has been studied using a one-dimensional analytical model. ...
Publisher
University of Jyväskylä
ISBN
978-951-39-7328-5
ISSN Search the Publication Forum
0075-465X
Keywords
valosähköinen ilmiö ionilähteet low temperature hydrogen plasma photoelectron emission ion source plasmafysiikka plasma (kaasu)
URI

http://urn.fi/URN:ISBN:978-951-39-7328-5

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  • Väitöskirjat [3040]

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