Evaluation of neutron cross sections of the sd-shell nuclei 27Al and 28,29,30Si

On the basis of nuclear models we have evaluated neutron cross sections of 27Al and 28,29,30Si at energies from 10-5 eV to 20 MeV. The model parameters, i.e. the nuclear level density parameters in the Gilbert-Cameron formula and the optical potential parameters for neutron, proton and alpha particle, were determined independently of the previous work. The calculations were mainly performed in the framework of the Hauser-Feshbach theory. However, the strong excitation of collective states by neutron inelastic scattering was fully considered with a coupled-channel Born approximation. As a result, we found that the calculations are in good agreement with recent experimental values in the whole neutron energy region. (author)