Multiple Scattering in Neutron Polarization Analysis

Abstract

An analytical method of correcting measured neutron polarization analysis spectra for .multiple scattering effects is presented. The multiple scattering corrections are applicable to any general instrumental and specimen geometries, and have been evaluated within the elastic quasi-isotropic scattering approximation. The results are appropriate for specimens where the total attenuation of the incident neutron beam is smalland where the multiple scattering is no more than about 20% of the total scattered intensity. Specific results have been calculated for the geometry of the LONGPOL polarization analysis instrument at the AAEC Research Establishment, and the theoretical predictions have been tested by examination of the neutron spin-dependent cross sections of a vanadium standard specimen measured using LONGPOL. Finally, the use of the analytical multiple scattering corrections is illustrated by reference to some recent measurements of spin-dependent cros-s sections-of anMnCu alloy obtained on LONGPOL