NEUTRONS AT THE BOUNDARY OF MAGNETIC MEDIA

The behavior of a neutron as a quantum-mechanical top at the boundary of two magnetically noncollinear media is analyzed. Attention is paid to such phenomena as splitting of reflected and refracted beams, total reflection 'forwards', cross interference, polarization and depolariz ation effects. The exact formulae are obtained for the reflectivity an d transmittance of neutrons with the spin precessing in the guide fiel d. In a weak guide field approximation, they are simplified and genera lized for a stratified, collinearly magnetized, medium and for oscilla ting 'guide' fields. It is pointed out that reflection of neutrons can be used to study the spin super-position and to carry out the Wigner experiment on the result of a quantum mechanic measurement. Neutron sp in turners including flippers can be made with mirrors on the basis of magnetically anisotropic thin films.