Study of neutron scattering cross sections and measurements

Elastic and inelastic neutron scattering angular distributions for 23Na sample were measured at the University of Kentucky using the time-of-flight (ToF) technique, between 1 and 4 MeV incident neutron energies. Neutrons were detected using a deuterated benzene detector with a smaller NE213 liquid scintillator as a monitor. Normalization of yields into scattering cross sections was accomplished by comparison of Na yields to the yields obtained from hydrogen in polyethylene samples via the well-known n-p scattering cross-sections. The largest components in the uncertainty are related to the 3H(p,n) differential cross sections and the multiple scattering and attenuation corrections. The 3H(p,n) differential cross sections are used to determine the energy-dependent efficiency of the main detector. Because the efficiency of this detector appears as a ratio in the comparison of scattered yields from different samples, the absolute values of the 3H(p,n) cross sections are not critical, but their energy dependence is. In the near future we will complete another series of angular distributions on 23Na at higher neutron energies and continue to evaluate multiple-scattering and attenuation corrections, and normalization procedures. (author)