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MS: Fachverband Massenspektrometrie

MS 4: Beschleunigermassenspektrometrie und Anwendungen I

MS 4.8: Vortrag

Mittwoch, 10. März 2010, 12:30–12:45, F 428

¹⁴C AMS measurement and sample preparation methods of µg-sized carbon samples — •Jakob Liebl¹, Simon Fahrni², Robin Golser¹, Walter Kutschera¹, Klaus Mair¹, Alfred Priller¹, Peter Steier¹, Iris Vonderhaid¹, Lukas Wacker³, and Eva Maria Wild¹ — ¹Vienna Environmental Research Accelerator (VERA), Faculty of Physics - Isotope Research, University of Vienna, Austria — ²Department of Chemistry and Biochemistry, University of Bern, Switzerland — ³Ion Beam Physics, Physics Department, ETH Zurich, Switzerland

¹⁴C AMS measurement and sample preparation methods for µg-sized samples have been developed at VERA. Overall measurement uncertainties do not primarily originate from the uncertainty of the AMS measurement itself, but are strongly affected by carbon contamination introduced during sample preparation. In contrast to contamination levels at graphitization, contamination introduced at earlier steps of sample preparation is sparsely investigated. At VERA, procedures with no detectable (<0.2 µg C) carbon contamination during graphitization, and contamination below 0.4 µg C during sample combustion and pretreatment were developed. Sample preparation procedures and graphitization protocols currently applied for small samples are presented. We will also discuss results of comparative AMS measurements of CO₂ samples (10 µg C), either graphitized and measured at VERA or introduced as CO₂ into a gas ion source installed at a MICADAS facility of the ETH Zurich. With both methods, we have reached a precision level of about 1% for ¹⁴C measurements of 10 µg C samples.