Microscopic and conventional optical model analysis of fast neutron scattering fromFe54,56

Differential cross sections for elastic scattering of neutrons from ${}_{}{}^{54,56}{}_{}{}^{}\mathrm{Fe}$ have been measured at several energies in the 20-26 MeV region. The data have been analyzed both in terms of the standard phenomenological optical model, and in the framework of two different microscopic models based upon nuclear matter calculations using realistic nucleon-nucleon interactions and a local density approximation. Isospin consistency of the microscopic-model calculations was also tested by analyzing proton elastic differential cross section data in the same energy region, as well as both proton and neutron elastic analyzing power data. The microscopic calculations yield quite reasonable agreement with the data, even though they contain no free geometrical parameters. The quality of the results for the analyzing power data is particularly impressive, indicating that the very simple, density- and energy-independent spin-orbit force used in the calculations is sufficient. The differences between the various models are clarified by examining the momentum-space representations of the potentials.