Larmor labelling, polarization analysis and its applications

Polarized neutron provides exceptional possibilities for neutron scattering. Neutron polarimetry allows for measurements of vector properties of neutron polarization and provides a unique way of recovering significant directional and phase information lost when only neutron intensities are measured. On the other hand, the Larmor precession of neutron spin in magnetic field allows us to attach a “Larmor clock” to every neutron. Such a Larmor labelling opens the unique possibility for the development of “unusual” neutron scattering techniques, where the energy (momentum) resolution is decoupled monochromatization (collimation) of incident and scattered neutron beams. In this article we are reviewing some latest developments both in methods of three-dimensional neutron polarimetry and instrumentation based upon the Larmor labelling.