Hannover 2010 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 4: Beschleunigermassenspektrometrie und Anwendungen I
MS 4.7: Vortrag
Mittwoch, 10. März 2010, 12:15–12:30, F 428
Improved measurements of gaseous 14C samples at Micadas — •Simon Fahrni1,2,3, Lukas Wacker4, Matthias Ruff1,2,4, Sönke Szidat1,3, and Hans-Arno Synal4 — 1Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland — 2Laboratory for Radiochemistry and Environmental Chemistry, Paul Scherrer Institute, Villigen, Switzerland — 3Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland — 4Ion Beam Physics, ETH Hönggerberg, Zurich, Switzerland
Samples of 1 to 40 µg carbon are measured as CO2 in the gas ion source of the small AMS facility MICADAS at ETH Zurich. This measurement technique offers a simple and fast way of 14C measurements without the need of sample graphitization. Low negative ion currents, however, are a drawback of gaseous measurements as they result in a reduced precision. To overcome this problem, we optimized several parameters of the new ion source at MICADAS. The performance now achieved allows to measure samples faster, more efficiently and with a higher precision. Therefore, the gas ion source at MICADAS even becomes feasible for dating in the 5 per mil range. A report on the state of our gas ion source is presented.