Düsseldorf 2007 – scientific programme

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MS: Fachverband Massenspektrometrie

MS 3: Neue Entwicklungen in der AMS

MS 3.2: Talk

Tuesday, March 20, 2007, 14:30–14:45, 5F

The new French 5 MV AMS facility: ASTERisques — •Didier Bourlès, Maurice Arnold, Georges Aumaître, Régis Braucher, Fredéric Chauvet, and Silke Merchel — CEREGE, CNRS-IRD-Université Aix-Marseille, F-13454 Aix-en-Provence, France

A new 5 MV accelerator mass spectrometry (AMS) system, developed by HVE, has been installed at CEREGE.

Ions are extracted from a hybrid ion source which can handle gaseous and solid samples. On the low-energy side the ions are separated by an energy-analyser, a 54° electrostatic deflector, and a mass-analyzer, a 90° magnet, equipped with a fast-bouncing system. The tandetron accelerator [1] contains a gas stripper and active stripper gas regulation. On the high-energy side, a 90° analysing magnet is followed by Faraday cups for stable isotope measurements. The rare isotopes are detected by a 4-anode gas ionization chamber after passing through an absorber foil, a 35° electrostatic deflector and a 30° vertical analysing magnet for further background reduction.

The system is fully dedicated to applied research. We will mainly measure long-lived (half-life > 100000 a) cosmogenic radionuclides isolated from geological and environmental samples. The determination of e.g. Be-10, Al-26, Cl-36 in bed rock, sediments and ice cores will help to reconstruct climatic changes, seismic activities, volcano eruptions and rock falls in the past [2]. Understanding past events will enable us to better predict such events in the future.

[1] A. Gottdang et al., NIMB 190 (2002) 177. [2] J.C. Gosse and F.M. Phillips, Quat. Sci. Rev. 20 (2001) 1475.