Mainz 2012 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 48: Poster – Nukleare Astrophysik
HK 48.10: Poster
Thursday, March 22, 2012, 14:00–16:00, P Foyer
Decay investigation of neutron-rich isotopes around the third r process peak — •Alexey Evdokimov1,2, Iris Dillmann1,2, and Michele Marta1,2 — 1GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany — 2II. Physikalisches Institut, Justus-Liebig Universität Giessen, Germany
The “rapid neutron capture” (r) process plays an important role in stellar nucleosynthesis and is responsible for about 50% of the solar abundances beyond iron. The solar r-abundance curve has three maxima at A∼80, 130 and 195, corresponding to neutron-rich precursors around N=50, 82, and 126. Up to now experiments close to the r process path were carried out only for A<150, leaving the region above as “terra incognita”. We have for the first time investigated neutron-rich Tl, Hg, Au, and Pt isotopes “south-east” of the N=126 shell closure for β-delayed neutron emission and their half-lives. The experiments were carried out with FRS at GSI with implantation set up consisting of a Si array surrounded by neutron detectors.
These heavy neutron-rich isotopes are also well-suited for a proposed proof-of-principle measurement of β-delayed neutron emitters in a storage ring. Since their half-lives are in the order of seconds, electron cooling can be applied, and the decay half-life and the neutron-emission probability could be deduced from the detection of decay daughters with a particle detector. This method is complementary to the standard method via detection of the neutron. The two experimental approaches are described and compared.