What is Neutron resonance spin echo?

Neutron resonance spin echo is a quasielastic neutron scattering technique developed by Gähler and Golub. In its classic form it is used analogously to conventional neutron spin echo spectrometry for quasielastic scattering where tiny energy changes from the sample to the neutron have to be resolved. In contrast to NSE, the large magnetic solenoids are replaced by two resonant flippers respectively. This allows for variants in combination with triple axes spectrometers to resolve narrow linewidth of excitations or MIEZE for depolarizing conditions and incoherent scattering which are not possible with conventional NSE.

Neutron spin echo techniques achieve very high energy resolution in combination with very high neutron intensity by means of a decoupling of the energy resolution of the instrument from the wavelength spread of the neutrons. The energy transfer of the neutrons is encoded in their polarization and not in the change of the wavelength of the scattered neutrons. The final neutron polarization provides the intermediate scattering function S, providing direct information on relaxation processes, activation energies, and the amplitudes of dynamic processes in the samples under investigation.