Hamburg 2009 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 4: AMS-Applications
MS 4.1: Hauptvortrag
Dienstag, 3. März 2009, 10:30–11:00, VMP 8 R05
Nuclear Astrophysics and AMS — •Anton Wallner — VERA Labor, Fakultät für Physik, Univ. Wien, Währinger Strasse 17, 1090 Wien, Austria
Nuclear astrophysics aims at describing nuclear processes relevant to nucleosynthesis. Except for the very light elements, the abundance pattern of our solar system is the product of nucleosynthesis within many generations of stars. Isotopic abundances can be studied in the laboratory via nuclear cross-section measurements at the relevant energy regimes. In cases of longer-lived nuclides or nuclides with an unfavorable decay scheme, counting atoms directly via Accelerator Mass Spectrometry (AMS) rather than their decay rates, is the far more sensitive method.
The general isotopic pattern for elements heavier than Fe can be understood as the result of a few distinct processes, like s-, r- or p-process. Interestingly, recent observations of very old, so-called ultra-metal-poor (UMP) stars indicate that our knowledge of nucleosynthesis is still limited. New precise AMS measurements will help to clarify this recently found discrepancy in UMP stars. In addition, the search for certain supernova-produced, long-lived radionuclides on Earth, like 60Fe, 182Hf, 244Pu and possibly super-heavy elements, will give an improved insight into explosive nucleosynthesis scenarios.
An overview on recent activities of the AMS technique in nuclear astrophysics will be given, including measurements relevant for Big-Bang nucleosynthesis and the search for SN-produced radionuclides on Earth.