Cross Section for "Ultracold" Neutrons I. Theory of Magnetic Scattering

Abstract

Abstract Very cold neutrons (typical wavelengths are about 102 Å) are available by recently developed techniques 2. The features of the scattering of these “ultracold” neutrons are investigated in the present paper discussing a few examples of magnetic scattering. The diffraction of neutrons by the vortex lattice in superconductors is treated as an example of elastic scattering, while in most other cases the scattering is inelastic. We discuss the scattering by ferromagnetic magnons at low temperatures and the critical scattering from an isotropic ferromagnet above the critical tempera­ture. Simple models are used to derive the total cross sections. It is shown that relevant information about the inealsticity can be gained by the measurement of total cross sections in these cases.