The differential cross section and polarization for the elastic scattering of 2.9 MeV neutrons by Fe, Cu, I, Hg and Pb

Abstract

Simultaneous measurements are presented of the angular dependence of polarization due to elastic scattering and of the elastic differential cross section for 2.9 MeV neutrons. The angular range covered is 20° to 160° for samples of Fe, Cu, I. Hg and Pb. The measurements are compared with the results of combining optical model and Hauser-Feshbach calculations. The optical model calculations were performed using “global fit” parameters as well as with parameters suggested previously for the particular nuclei. The Hauser-Feshbach calculations were performed both with and without the level width fluctuation correction. It is clear that the calculations made without the level width fluctuation correction provide a better fit to the data for Fe, Cu, I and Hg and only for Pb does inclusion of the level width fluctuation correction provide a better fit. These optical model parameter sets are shown not to be very successful in fitting both differential cross-section and polarization data. The results of searches for the parameters which give the best fit for the data are presented. These parameter sets are compared with one another and with the results of 8 and 11 MeV neutron scattering studies for trends in the variation of the parameters.