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VA: Vakuumphysik und Vakuumtechnik

VA 4: Große Vakuumsysteme und Beschleuniger

VA 4.2: Vortrag

Montag, 26. März 2001, 15:30–15:50, R221

The Electron-Induced Desorption of Copper After Various Cleaning Treatment — •G. Vorlaufer, N. Hilleret und H. Störi — CERN, /LHC Division, GENEVA Switzerland

The desorption of gases from vacuum chambers submitted to the impact of photons and/or ions/electrons is the main source of outgassing in high-energy particle accelerators. Well-established cleaning methods like vacuum bake-out or glow discharge treatment have been successfully applied in the past to reduce this phenomenon. Currently a new approach for the in situ cleaning of vacuum chambers by free radicals (i.e. dissociated molecules) is being investigated in the CERN Vacuum Group. These radicals are produced by a microwave plasma source and pumped through a vacuum chamber where they react with the surface producing a change in composition. To investigate these modifications, the electron-induced desorption yield of treated samples has been measured in situ. The set-up will be described as well as the first results obtained, showing the influence of various radicals on the desorption of copper.