High luminosity inverse geometry inelastic neutron scattering spectrometer at pulsed fast reactor

The project of a new inelastic neutron scattering (INS) spectrometer in inverse geometry at the IBR-2 pulsed fast reactor (JINR, Dubna, Russia) has been proposed as a replacement for the old NERA instrument. The major feature of the proposed spectrometer is the substantially increased area of the energy analyzer, made of highly oriented pyrolytic graphite (HOPG). We developed a new method of constructing the large area reflecting surface of the energy analyzer for the time-of-flight INS spectrometer in inverse geometry at the pulsed neutron source. According to our calculations, the total area of the HOPG analyzer would be as large as 3.14 m2 with a solid angle coverage of 5.8 sr. In comparison with the existing NERA spectrometer, this gives a factor of thirty in enhancement of the spectrometer's luminosity.