Calculations of neutron reflectivity in the eV energy range from mirrors made of heavy nuclei with neutron-nucleus resonances

Abstract

We evaluate the reflectivity of neutron mirrors composed of certain heavy nuclei which possess strong neutron-nucleus resonances in the eV energy range. We consider possible corrections to the usual formulas of neutron optics for this case and find that dispersion and multiple scattering effects are negligible but one must take Doppler broadening into account. Effects from surface roughness and phonon scattering are small compared to the Doppler corrections and are either the same as or smaller than those for mirror reflection with meV neutrons. We show that the reflectivity of such a mirror for some nuclei can in principle be high enough near energies corresponding to compound neutron-nucleus resonances to be of interest for certain scientific applications in nondestructive evaluation of subsurface material composition.