Berlin 2005 – wissenschaftliches Programm
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MS: Massenspektrometrie
MS 5: Beschleuniger-Massenspektrometrie 1
MS 5.1: Hauptvortrag
Samstag, 5. März 2005, 10:30–11:00, HU 3088
Latest developments in low energy AMS — •Hans-Arno Synal1, Michal Grajcar2, Max Döbeli1, Mark Stalder2, Martin Stocker1, Martin Suter2, and Lukas Wacker1 — 1PSI c/o ETH Hönggerberg — 2ETH Hönggerberg
In recent years, low energy radiocarbon dating systems using accelerators with terminal voltages of less than 1 MV have demonstrated their ability to produce high quality radiocarbon dates. In addition, it has been demonstrated that this type of facilities have also a potential for the detection of other radioisotopes, but the background measured was in general higher compared to the larger accelerators. We focus on improvements of detectors for low energetic heavy particles and on modifications in the ion optics of low energy AMS spectrometers leading to conditions, which provide now competitive results for most relevant radioisotopes studied by AMS. Experiments at our laboratory showed that radiocarbon detection remains feasible at terminal voltages of 200 kV. Based on our results we have built a novel tabletop sized radiocarbon detection system with overall dimensions of 2 m x 3 m only for which the terminal voltage can be provided by a commercial power supply with a maximum voltage of 200 kV. The system is now operational and first test have demonstrated its capability of high performance radiocarbon isotopic ratio measurements. The physical processes behind the method will be discussed and an overview on the technical concept of the prototype of this new generation of AMS spectrometers will be given.