FLEXX provides the opportunity to combine triple axis spectroscopy and high resolution spin-echo spectroscopy. The neutron resonance spin echo method (NRSE) is based on the use of RF spin flippers. In contrast to conventional spin echo spectrometers the static precession fields are replaced by precisely synchronised pairs of RF flippers, with no magnetic field in between.
The NRSE option at FLEXX is particularly suited for spin echo focussing with tilt fields. By this method the line widths of dispersive elementary excitations can be measured with an energy resolution in the μeV range.