Neutron Scattering Cross Section as a Function of Energy

The study of scattering of neutrons of energy range from 0.02 to 80 volts from Fe, Ni, and Pb has been completed by measuring the activation of Ag, Rh, and CH${\mathrm{I}}_3$ detectors. The scattering of $C$ neutrons was determined indirectly by two methods, and the results agreed closely. The scattering cross section for Ni fell off slowly with neutron velocity, that for Pb increased slightly, while that for Fe remained constant over the range from 0.02 to 80 volts. The directional distribution of neutrons emerging from the top of a paraffin cylinder containing a Ra-Be neutron source was investigated by placing detectors at various distances above the top of the paraffin. The results agreed well with those calculated for a cosine distribution law.