Asymmetric total reflection of polarized neutrons and the neutron as a surface probe

Total reflection of neutrons which are polarized perpendicular to the plane of incidence is invariant to beam reversal in the usual formalism of the index of refraction for neutrons. A modified formalism which includes the spin-orbit interaction of the neutrons in the electric field present at the surface of the reflecting medium is developed in this paper. The asymmetry predicted is proportional to the surface dipole potential of the mirror and provides a method of direct measurement of the surface dipole.