Mainz 2012 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 31: Nukleare Astrophysik

HK 31.6: Vortrag

Mittwoch, 21. März 2012, 18:15–18:30, RW 2

⁵⁹Fe(n,γ)⁶⁰Fe constrained by Coulomb Dissociation — •Tanja Heftrich — Goethe Universität Frankfurt a. M., Germany

One of the fundamental signatures for active nucleosynthesis in our galaxy is the observation of long-lived radioactive elements using γ-ray observatories such as INTEGRAL. Of particular importance are the two long-lived radioactive isotopes ²⁶Al and ⁶⁰Fe. The production of ⁶⁰Fe is associated with the Helium shell burning phase in AGB stars or with the hot carbon/oxygen shell burning phase in massive pre-supernova stars. Very little is known about the reactions associated with the nucleosynthesis of ⁶⁰Fe. The production rate ⁵⁹Fe(n,γ)⁶⁰Fe is very difficult to measure directly because of the short half-life of ⁵⁹Fe (t_1/2=44.5 d). Coulomb dissociation measurements of ⁵⁹Fe and ⁶⁰Fe were performed at the R³B/LAND setup at GSI. The unstable iron isotopes were produced by fragmentation of a 660 AMeV primary beam of ⁶⁴Ni on a 4 g/cm² Be target. The dissociation cross section ⁶⁰Fe(γ, n)⁵⁹Fe allows to constrain the theoretical estimates of the inverse neutron capture reaction ⁵⁹Fe(n,γ)⁶⁰Fe via detailed balance. In order to prove this method, ⁵⁹Fe(γ, n)⁵⁸Fe was studied in addition to compare with the already directly measured ⁵⁸Fe(n,γ)⁵⁹Fe cross section. The astrophysical motivation, an overview of the experimental setup and the status of the analysis will be presented. This project is supported by the HGF Young Investigator Project VH-NG-327.