Cross section of inelastic polarized neutron scattering by superconducting rings

A general expression for the cross section of inelastic magnetic scattering of cold polarized neutrons by superconducting rings has been derived. In this scattering process, the metastable superconducting current changes via quantum jumps corresponding to a decrease in the number of fluxoids in the superconducting ring by one or several units and the change in the energy of the ring is transferred to the kinetic energy of the scattered neutron. For rings from type-II superconductors with a thickness smaller than the field penetration depth but larger than the electron mean free path, the cross sections of inelastic scattering with neutron spin flip have been obtained for the first time. The possibility of increasing the cross section of neutron scattering by a system of rings has been discussed.