Analyzing power ofAl27(n→,n→0) at 14 and 17 MeV and the isospin dependence of the optical model potential

The analyzing powers of 14 and 17 MeV neutrons elastically scattered from ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ have been measured. Two spherical optical model analyses of these and previously published data have been performed. The first one, which concentrated only on neutron cross section data at 14 and 17 MeV and the new analyzing powers, led to a new set of spherical optical model parameters, including a spin-orbit strength and a diffuseness of about 5.6 MeV and 0.36 fm, respectively. The second incorporated cross section and analyzing power data for proton scattering at slightly higher energies, to compensate for Coulomb energy differences. The data were successfully described with a set of parameters which included isospin-dependent potentials with isospin parameters $V_{1R}$=22.4 MeV and $W_{1D}$=15.7 MeV.