γ detectors for deep inelastic neutron scattering in the 1-100 eV energy region

The Resonant Detector Technique (RDT) is a very promising technique for neutron spectroscopy in the epithermal energy region above 1 eV at spallation neutron sources. In this technique, using the (n, γ) reactions, the energy of the scattered neutrons is assigned by revealing the prompt γ ray cascade from the absorbing foil through a γ detector. The advantages of this technique, as compared to the Single Difference Technique (SDT) currently used on eVS spectrometer at ISIS, are presented. Different choices of converter foils and γ detectors will be compared and discussed, especially in terms of their efficiency and background insensitivity.