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Home / Publications / Journals / Nuclear Science and Engineering / Volume 159 / Number 2 / Pages 213-220

Modeling of High-Precision Neutron Nonelastic Cross Sections

F. S. Dietrich, J. D. Anderson, R. W. Bauer, S. M. Grimes, D. P. McNabb

Nuclear Science and Engineering / Volume 159 / Number 2 / June 2008 / Pages 213-220

Technical Paper

A new method has been applied to the determination of neutron nonelastic cross sections for iron 56Fe and lead 208Pb for energies between 5 and 26 MeV. These data have estimated errors of only a few percent and do not suffer from the ambiguities encountered in earlier nonelastic data. We attempt to fit these high-precision data using both a semiclassical single phase shift model (nuclear Ramsauer model) as well as a recent global optical model that well reproduces a wide body of neutron scattering observables. At the 5% uncertainty level, both models produce satisfactory fits. However, neither model gives satisfactory fits to these new precise data. We conclude that fitting precise data, i.e., data with errors of ~2% or less, may require a nuclear mass dependence of radii that reflects structure effects such as shell closures.

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