Hannover 2016 – wissenschaftliches Programm

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MS: Fachverband Massenspektrometrie

MS 9: Accelerator Mass Spectrometry and Applications II

MS 9.1: Hauptvortrag

Donnerstag, 3. März 2016, 14:30–15:00, f128

Multi-actinide analysis with AMS for ultra-trace determination and small sample sizes: advantages and drawbacks — •Francesca Quinto¹, Markus Lagos¹, Markus Plaschke¹, Thorsten Schäfer¹, Peter Steier², Robin Golser², and Horst Geckeis¹ — ¹Institute for Nuclear Waste Disposal, Karlsruhe Institute of Technology, Germany — ²VERA Laboratory, Faculty of Physics, University of Vienna, Austria

With the abundance sensitivities of AMS for U-236, Np-237 and Pu-239 relative to U-238 at levels lower than 1E-15, a simultaneous determination of several actinides without previous chemical separation from each other is possible. The actinides are extracted from the matrix elements via an iron hydroxide co-precipitation and the nuclides sequentially measured from the same sputter target. This simplified method allows for the use of non-isotopic tracers and consequently the determination of Np-237 and Am-243 for which isotopic tracers with the degree of purity required by ultra-trace mass-spectrometric analysis are not available. With detection limits of circa 1E+4 atoms in a sample, 1E+8 atoms are determined with circa 1 % relative uncertainty due to counting statistics. This allows for an unprecedented reduction of the sample size down to 100 ml of natural water. However, the use of non-isotopic tracers introduces a dominating uncertainty of up to 30 % related to the reproducibility of the results. The advantages and drawbacks of the novel method will be presented with the aid of recent results from the CFM Project at the Grimsel Test Site and from the investigation of global fallout in environmental samples.