Program - Brookhaven National Laboratory

A Regional Coupled-channel Dispersive Optical Potential for Fe Isotopes
Weili Sun, Institute of Applied Physics and Computational Mathematics, Beijing 100094, China. Rui Li,
Graduate School, China Academy of Engineering Physics, Beijing, 100088, China. E. Soukhovitskii,
Joint Institute for Power and Nuclear Research, 220109, Minsk, Belarus. J. M. Quesada, Universidad de
Sevilla, Apartado Postal 1065, E-41080 Sevilla, Spain. R. Capote, NAPC-Nuclear Data Section,
International Atomic Energy Agency, Vienna, A-1400, Austria.
A regional Lane-consistent dispersive coupled-channel nucleon optical potential for Iron is suggested. Realistic
saturated coupling for 54,56,58 Fe was built using soft-rotator nuclear wave functions with the nuclear
Hamiltonian parameters adjusted to reproduce low-lying collective levels of these isotopes. All experimental
optical data: neutron total, nucleon reaction cross sections and angular distributions for 54,56,58 Fe
are described with reasonable accuracy up to 200 MeV incident energies. The E2 and E3 γ-transition
probabilities between low-lying collective levels are also well reproduced. Moreover the potential described
well the quasielastic (p,n) reaction with excitation of IAS states, proving that isovector potential terms are
reliable to predict the right isotopic dependence of the potential. In general, good agreement between experimental
data and calculation is achieved for both collective levels and nucleon interaction data, showing
this suggested potential being self-consistent.
BC 2 11:00 AM
Coupled-channels Determination of Actinide Optical Potentials
Ian J. Thompson, Frank S. Dietrich and W. Erich Ormand
Lawrence Livermore National Laboratory, L-414, Livermore CA 94551
It has been discovered [1] that the convergence of coupled-channels calculations for neutrons on rotational
nuclei is not as good as previously thought. The convergence of the compound nucleus production (a.k.a
fusion) cross section is particularly slow as the number of coupled states is increased. This requires us
to reevaluate the fitting of optical potentials that reproduce existing neutron-nucleus scattering data,
especially in the energy range up to 5 MeV. We report on new work to determine a suitable potential that
should enter into coupled-channels calculations for neutron scattering on actinides, and which takes into
account the needed extension of the coupling scheme. Deformations were obtained from charged-particle
scattering data at higher energies on 232 Th and 238 U, and scaled for other nuclei according to B(E2)
data [2]. We show the fits obtained when comparing our neutron calculations to total cross sections, to
elastic and inelastic scattering, and also the neutron strength functions extracted from resonance data.
Below 1 MeV, the compound elastic contributions were obtained by Hauser-Feshbach calculations with the
Livermore code YAHFC. Our results are compared with those from previously proposed actinide optical
potentials. Prepared by LLNL under Contract DE-AC52-07NA27344.
[1] F.S. Dietrich, I.J. Thompson and T. Kawano, Phys.Rev.C 85, 044611 (2012) [2] S. Raman, C.W. Nestor
and P. Tikkanen, At. Dat. Nucl. Dat. Tables 78, 1 (2001)
BC 3 11:20 AM
Exclusive Multiple Emission Cross Sections in the Hybrid Monte Carlo Pre-Equilibrium
Model
B. V. Carlson, L. Brito, D. F. Mega
Instituto Tecnológico de Aeronáutica, São José dos Campos SP, Brazil
R. Capote
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