Small Angle Diffraction of Neutrons and Similar Wave Phenomena

Abstract

A study of the diffraction of waves under very small angles is presented; the diffraction objects are ideal microcrystals, crystallites, assemblies of polycrystals and amorphous bodies. The diffraction cross section was found to depend in a very sensitive way on the angle of scattering and on the nature and orientation of the scattering object. The most significant result found consisted in the observation that the integral cross section of the diffraction object is in general proportional not to the number $Z$ of atoms contained in the scatterer but to a higher power ($Z^{\frac{4}{3}} or Z^{\frac{7}{6}}$). The results are applied to the interpretation of a number of experiments on the small angle scattering of neutrons and of light waves; possible effects on the polarization of neutrons are also discussed.