Gamma 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, gamma) reactions, the energy of the scattered neutrons is assigned by revealing the prompt gamma ray cascade from the absorbing foil through a gamma 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 gamma detectors will be compared and discussed, especially in terms of their efficiency and background insensitivity.