Mainz 2017 – scientific programme

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MS: Fachverband Massenspektrometrie

MS 9: Accelerator Mass Spectrometry and Applications II

MS 9.1: Talk

Thursday, March 9, 2017, 14:30–14:45, RW 2

AMS measurements of ²⁶Al at ETH Zurich — •Christof Vockenhuber¹, Marcus Christl¹, Klaus-Ulrich Miltenberger¹, Arnold Müller¹, Kristina Hippe¹, and Naki Akçar² — ¹Laboratory of Ion Beam Physics, ETH Zurich, Switzerland — ²Institute of Geological Sciences, University of Bern, Switzerland

At ETH Zurich ²⁶Al has been measured for many decades at the 6 MV EN tandem accelerator. Compared to other cosmogenic rationuclides (e.g. ¹⁰Be), the number of samples was always smaller because of the limited precision that could be achieved. A key challenge is the low ionization efficiency of ²⁶Al⁻ (from an Al-oxide matrix) required to suppress the isobar ²⁶Mg. Recent developments at low energies at the 500 kV TANDY promised significant improvements in overall efficiency due to higher transmission through the accelerator. Alternatively, the ionization efficiency can be increased by using ²⁶AlO⁻ from the ion source; however, then, high ion energies and the gas-filled magnet (GFM) are necessary to remove the majority of interfering ²⁶Mg before the final detector. In this talk we will give a comparison of the measurement methods at ETH Zurich, present their performance under routine measurement conditions and finally discuss the advantages and limitations of each setup.