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HK: Fachverband Hadronen und Kerne
HK 16: Nuclear Structure and Dynamics II
HK 16.6: Talk
Monday, March 16, 2009, 18:00–18:15, H-ZO 60
Electron-capture delayed fission (ECDF) in the lead region — •Martin Venhart1, Andrei Andreyev1, Stanislav Antalic2, Jytte Elseviers1, Dieter Ackermann3, Fritz Peter Hessberger3, Sigurd Hofmann3,4, Mark Huyse1, Katshuhisa Nishio5, Piet van Duppen1, and Cyrillus Wagemans6 — 1IKS, KU Leuven, Belgium — 2Comenius University, Bratislava — 3GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany — 4Goethe-Universität, Frankfurt am Main, Germany — 5JAEA, Japan — 6University of Ghent, Belgium
Beta-delayed fission is a rare process in which the beta-decaying precursor populates relatively low-excited state in its decay daughter, which may then fission. This allows to study low-energy fission properties e.g. the isospin dependence of the fission barriers. It is currently believed that the beta-delayed fission process is crucial for understanding the r-process path and for the production of the heaviest elements.
In the presentation, the recent experiments performed at the velocity filter SHIP (GSI) and at the mass-separator ISOLDE (CERN) will be discussed. In these experiments, the ECDF decay was unambiguously observed in several very neutron-deficient nuclides in the Pb region (192,194At and 180Tl). ECDF probability and total kinetic energy were determined. Surprisingly, an asymmetric mass distribution of fission fragments was observed in ECDF of 180Tl. Preliminary analysis also shows that the cold fission (no neutron emission) might be the main decay channel in the ECDF decay of this nucleus.