THEORY OF ELECTROSTATIC SCATTERING OF THERMAL NEUTRONS BY SOLIDS

The paper is concerned with the consequences of the electrostatic interaction involved in the scattering of thermal neutrons by both non-magnetic and magnetic crystals. The terms in the cross section and, also, in the polarization of an initially unpolarized beam, additional to those coming from just the nuclear and magnetic interactions are calculated. It is pointed out that the electrostatic interaction consists of two terms, first, the well known spin-orbit term considered by Schwinger and secondly, the so-called Foldy interaction which has been omitted in previous calculations for the scattering of thermal neutrons by crystals. The inclusion of the Foldy interaction is shown to modify significantly the previous results.