Small-Angle Scattering of Neutrons by Heavy Nuclei

The differential cross sections and polarizations of neutrons elastically scattered by U, Th, Pb, Au, W, and Cd have been measured for scattering angles between 1.75° and 15°. The range of neutron energies covered is from 0.6 to 1.6 MeV. These data show no evidence for any anomalous long-range neutron-nucleus interaction. The data are used to evaluate an upper limit for the absolute value of the real part of the forward-scattering amplitude at each energy for each of the above scattering samples. The polarization of neutrons that emerge at 51° relative to the proton-beam direction in the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}(p, n){}_{}{}^7{}_{}{}^{}\mathrm{Be}$ reaction (the neutron-source reaction) is determined by use of these small-angle results for proton energies between 2.47 and 3.55 MeV. Some of the advantages of the use of small-angle neutron scattering as a polarization analyzer are discussed.