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MS: Fachverband Massenspektrometrie

MS 5: Präzisionsmassenspektrometrie und Anwendungen I

MS 5.1: Hauptvortrag

Mittwoch, 10. März 2010, 14:00–14:30, F 428

Progress in Mass Spectrometry of Exotic Nuclei at the FRS-ESR Facility at GSI — •Wolfgang Plaß — GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt — Justus-Liebig-Universität Gießen

Storage ring mass spectrometry at the FRS-ESR facility at GSI offers unique capabilities for the research with exotic nuclei. Schottky Mass Spectrometry (SMS) allows for broadband mass measurements with mass accuracies on the level of 0.2 ppm, whereas Isochronous Mass Spectrometry (IMS) gives access to nuclei with lifetimes as short as a few tens of microseconds. Both methods are sensitive to single ions and can be used to investigate the decay and the lifetime of exotic nuclei.

Using SMS, mass measurements of uranium projectile fragments in the element range Pt to U have been performed. Five isotopes and six isomers have been observed for the first time, the masses of 35 nuclides have been measured for the first time, and the proton-neutron interaction strength at the doubly magic shell closure of lead has been determined. Methodical improvements have enabled a first broadband IMS experiment on uranium fission fragments, addressing nuclei in the vicinity of the r process path. The 4.6 MeV isomeric state in ¹³³Sb has been measured directly for the first time, whose neutral-atom lifetime is 17 µs only.

For storage ring mass spectrometry at the international accelerator facility FAIR a detection system for IMS is being developed, which offers significantly improved accuracy, detection efficiency and rate capability compared to the system available at GSI currently.