Dispersive optical-model and coupled-channels descriptions of neutron scattering from ²⁷Al and ⁵⁹Co up to 80 MeV

Differential cross sections σ(θ) and analyzing powers A y(θ) have been measured for neutron scattering from 27Al and 59Co at 15 MeV at the Triangle Universities Nuclear Laboratory using standard time-of-flight techniques. In addition, σ(θ) was measured for 59Co at 10, 12, 14, 17, and 19 MeV. Two large databases covering the energy range from 0.1 to 80 MeV were formed for these nuclei from this new data and previously published data, including that for the total cross section σ T. These sets of data were analyzed using spherical dispersive optical-model (DOM) potentials, as well as coupled-channels model (CCM) potentials. The 59Co DOM gives good agreement with the σ(θ) data, except in the region of the first minimum. It also gives a reasonable description of our A y(θ) measurement. The 27Al DOM gives good agreement with the data, except for σ(θ) at backward angles below 9.4 MeV and for σ T, for which there is up to 5% disagreement in the 10-50 MeV range. Compared to the DOM, the 59Co CCM calculations give improved agreement with the σ(θ) data, especially at the first minimum. The σ T calculations agree with the data to within about 3% above 1.0 MeV. The three-level CCM calculations for 27Al give excellent agreement with the entire database.

Duke Scholars

Author Calvin R. Howell Physics