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HK: Fachverband Physik der Hadronen und Kerne
HK 61: Nukleare Astrophysik
HK 61.1: Group Report
Friday, March 21, 2014, 14:00–14:30, HZ 4
Triaxiality as essential feature for electromagnetic strength, level density and neutron capture cross sections in heavy nuclei — •Eckart Grosse2, Arnd R. Junghans1, and Ralph Massarczyk1,2 — 1Institut für Strahlenphysik, Helmholtz Zentrum DD-Rossendorf, 01328 Dresden — 2Institut für Kern- und Teilchenphysik, TU Dresden, 01069 Dresden
Reliable predictions for compound nuclear processes leading to nuclides outside the valley of stability are of importance for nuclear astrophysics as well as for the transmutation of nuclear waste. Assuming triaxiality in nearly all nuclei with A>70 a combined parameterization is presented for level density and photon strength. For the strength functions a fit to IVGDR shapes by the sum of three Lorentzians adding up to the TRK sum rule is used. Only two global fit-parameters are needed and a third one suffices to also describe level densities sufficiently well, if the significant collective enhancement due to the loss of axial symmetry is accounted for. Predicted level distances for the small spins reached by capture at the neutron threshold agree well to observations for more than 100 spin-0 target nuclei. Simultaneously derived neutron capture cross sections in the range of unresolved resonances are in accord to experimental findings as well as to Maxwellian averages (kT=30 keV) of neutron capture cross sections compiled recently for simulations of nuclear reactions in AGB-stars.