Magnetic substances and fields in the neutron interferometer

Known results are presented which describe the spinor part of a neutron wave function under the influence of (a) a magnetic field with varying strength but constant direction and (b) a magnetic field of constant strength with the direction rotating around an axis and they are then applied to the case of a neutron interferometer. Formulae are given for the intensities and polarizations respectively for cases (a) and (b) both without and with a nuclear phase shifter. Several special cases in which the relevant equations can be considerably simplified by appropriate assumptions are listed. (UK)