Hannover 2010 – scientific programme

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MS: Fachverband Massenspektrometrie

MS 4: Beschleunigermassenspektrometrie und Anwendungen I

MS 4.7: Talk

Wednesday, March 10, 2010, 12:15–12:30, F 428

Improved measurements of gaseous ¹⁴C samples at Micadas — •Simon Fahrni^1,2,3, Lukas Wacker⁴, Matthias Ruff^1,2,4, Sönke Szidat^1,3, 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.