Scattering and Polarization of Neutrons from Al, Si, Fe, and Co at 2 MeV

Abstract

Angular distributions of elastic scattering and polarization from $\ensuremath{\theta}=30 \mathrm{to} 120\ifmmode^\circ\else\textdegree\fi{}$, have been obtained for Al, Si, Fe, and Co at ${\mathrm{E}}_{n}=1.95\ifmmode\pm\else\textpm\fi{}0.09$ MeV, using polarized neutrons from the $\mathrm{T}(p, n){\mathrm{He}}^{3}$ reaction. Scattering and polarization from the 0.845---MeV level of ${\mathrm{Fe}}^{56}$ were also measured; an isotropic angular distribution and zero polarization were found for this level. The angular distributions of the elastic polarization for Si, Fe, and Co were negative at forward and backward angles with two zero cross-over points; the first zero of the polarization occurs approximately at the minimum of the elastic scattering for these three elements. In distinct contrast, the angular distribution of the polarization for Al is positive and constant at forward angles, becoming negative at backward angles. Absolute cross sections were obtained by scattering from polyethylene and an optical-model analysis of the experimental results was made.