Frankfurt 2006 – wissenschaftliches Programm
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MS: Massenspektrometrie
MS 2: Beschleuniger-Massenspektrometrie 2
MS 2.8: Vortrag
Montag, 13. März 2006, 18:15–18:30, H1
AMS 36Cl measurements at low beam energies — •V. Alfimov1, M. Suter1, H.-A. Synal2, and L. Wacker1 — 1ETH, CH-8093 Zürich — 2PSI/ETH, CH-8093 Zürich
Recent advances of AMS have shown that measurements of long-lived radionuclides 14C, 10Be, 41Ca and 129I are possible at low energies available at small tandem accelerators ( 1 MV). Isobars of these radionuclides are suppressed by either the use of negative ions or chemical methods. However, in the case of a long-lived radionuclide 36Cl, its isobar 36S cannot be completely removed by available chemical procedures and has to be separated at the final detector. Up to the present day, the 36Cl/36S resolution required for natural samples can be achieved only at high energies (>40 MeV) and large tandem accelerators (>5 MV). This situation might be changed, because the higher-order phenomena of stopping and straggling occurring at low energies result in better detector resolution than expected from high energy experiments. These phenomena, together with new ultra-thin Si3N4 windows, lay the grounds for a new generation of gas ionization detectors, which might provide sufficient resolution for 36Cl AMS at low energies. In order to test low energy 36Cl AMS, we have constructed a gas-ionization detector with specially designed anode plates. The 36Cl measurements were conducted at 10 MeV ion kinetic energy expected to give an improved detector resolution. In this contribution we will present our results on low energy 36Cl measurements and discuss possibilities and limitations of the method.