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SYPS: Symposium Precision spectroscopy of highly ionized matter
SYPS 1: Precision spectroscopy of highly ionized matter I
SYPS 1.4: Hauptvortrag
Freitag, 12. März 2010, 12:30–13:00, A 001
Measurements of masses and beta-lifetimes of stored exotic highly charged ions — •Fritz Bosch — GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
The ion storage-cooler ring ESR at GSI-Darmstadt, coupled to a high-energy synchrotron and a fragment separator, allows addressing the ground state properties of stored and cooled, highly charged exotic ions, in particular their masses and beta-lifetimes. For direct mass measurements two techniques were developed and continuously improved, namely Schottky-Mass-Spectrometry (SMS) for long-lived (half-life > 1 s), and Isochronous-Mass-Spectrometry (IMS) for short-lived (half-life > 10 µs) nuclides. Both of these complementary methods provided an overwhelming harvest during the last few years. Masses of several hundreds of nuclides could be determined with relative accuracies of better than 5 × 10−7 (SMS) and 5 × 10−6 (IMS), respectively, and at the ultimate sensitivity of one single stored ion. Thus, even nuclei very far from stability can be reached providing bright perspectives, in particular for experiments at the FAIR storage rings to come. Furthermore, for the first time, two-body beta decay of highly charged ions could be investigated at the ESR, which has an obvious impact for nucleosynthesis in hot stellar plasmas. In this context the orbital electron capture decay of hydrogen-like and helium-like ions was addressed. The still puzzling results obtained by single-ion decay spectroscopy, a technique recently developed at the ESR, will be presented and tentatively interpreted.