Multiple small-angle neutron scattering for an arbitrary value of the born parameter

Abstract

Computer calculations are made of the intensity of multiple small-angle neutron scattering using the general Moliere formula [8] over a wide range of variation of the Born parameter, embracing the diffraction and refraction regimes, and a transition region between diffraction and reflection. A comparison is made with approximate formulas obtained earlier by Maleev et al. [9, 10] in the limiting cases of the Born parameter α ≪ 1 and α ≫ 1 for the diffraction and refraction regimes, respectively. It is shown that over a wide range of values of α the results of the calculations using the approximate and general formulas are the same. The theoretical conclusions were checked experimentally using data from measurements of small-angle neutron scattering for the domain structure of ferromagnets. Measurements were made of the neutron beam broadening for samples of different thickness and these were used to determine the effective domain sizes in pure iron and nickel exposed to thermal treatment and plastic deformation, and also in the Invar alloys Fe65Ni35and Fe3Pt. An analysis is made of the angular dependence of magnetic small-angle neutron scattering at the asymptote.