Complex spin-orbit potential forPb208(n, n)Pb208at 10 MeV

Abstract

The analyzing power ${A}_{y}(\ensuremath{\theta})$ and differential cross section $\ensuremath{\sigma}(\ensuremath{\theta})$ have been measured for elastic scattering of 10-MeV neutrons from $^{208}\mathrm{Pb}$. These data were analyzed with a spherical optical model which has a real spin-orbit potential with either a three-parameter conventional form or a one-parameter semimicroscopic form. The predictions with both spin-orbit potentials reproduce the data equally well, suggesting that fewer free parameters can be used in spherical optical model calculations. Including an imaginary spin-orbit term ${W}_{\mathrm{SO}}(r)$ in the optical potential greatly improves the fits to the ${A}_{y}(\ensuremath{\theta})$ measurements and establishes the need for ${W}_{\mathrm{SO}}(r)\ensuremath{\ne}0$ in the n + $^{208}\mathrm{Pb}$ potential.NUCLEAR REACTIONS $^{208}\mathrm{Pb}$(n, n); $E=10$ MeV; measured $\ensuremath{\sigma}(\ensuremath{\theta})$, ${A}_{y}(\ensuremath{\theta})$; deduced complex spin-orbit potential; spherical optical model calculations.