Berlin 2001 – wissenschaftliches Programm

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MS: Massenspektrometrie

MS 5: Mass Spectrometry: Posters

MS 5.3: Poster

Dienstag, 3. April 2001, 12:30–15:00, AT2

Accumulation of Gold Ions on a Gold Coated Quartz Crystal — •Eckhard Finke, Dirk Ratschko, Dieter Knolle, and Michael Gläser — Physikalisch-Technische Bundesanstalt (PTB), Laboratory of Mass, Bundesallee 100, D-38116 Braunschweig, Germany

A new experiment has been started to determine the atomic mass of gold in the unit kilogram. For this purpose, gold ions have to be accumulated to a weighable mass and the ion current has to be measured and integrated over the accumulation time. In a first accumulation experiment gold ions have been accumulated on a gold coated quartz crystal. In order to analyse the effects of the gold ion beam on the surface of the quartz crystal (sputtering, refection, etc.) we have changed the mean ion energy in the range between 20eV and 320eV. The ratio of the change of mass and the time integral over the ion current have been determined as a function of the mean ion energy. The value of this function is proportional to the mass change per incident ion. The measurements have shown a reasonable agreement with the expected value of the mass of a gold atom in the unit kilogram for low ion energies.