The neutron spectrometer BRISP: a new approach to the study of excitations in condensed matter at low momentum transfer in the milli-eV energy region

The neutron Time-of-Flight BRIllouin SPectrometer BRISP for inelastic neutron scattering at small angles was developed and constructed at ILLs High Flux Reactor for investigating a host of open scientific problems in the low- momentum region with relatively high incoming neutron energies. With this dedicated instrument, the high-frequency dynamics of atomic nuclei and electron spins is studied in rather dierent materials. Originally planned for the investigation of disordered and magnetic systems, BRISP has immediately found a natural experimental extension to the study of those systems that have attracted in recent years a growing interest in the scientific community e.g. confined liquids, glasses, and biological macromolecules. A presentation of the instrument will be provided together with the illustration of some recent promising experiments.