Neutron Experiments

The great majority of the neutron scattering experiments performed by the L&SM group took advantage of the large scale facility including the high-flux reactor of the Institute Laue-Langevin (ILL) in Grenoble, France.

Past experiments largely employed an instrument for Neutron Brillouin Scattering constructed at the ILL by the Italian scientific community in collaboration with Germany. BRISP (BRIllouin SPectrometer) was designed to access low ranges of wavevector transfer Q (approximately between 3 and 16 nm-1) with rather high (80 meV) energy neutrons. Such a condition was achieved by detecting the scattered neutrons at very low scattering angles around the direct beam by means of a two-dimensional 3He-based gas Position Sensitive Detector. The probed dynamical range is the most interesting in studies of the collective dynamics ("pseudo-phonons") of liquids, to which the use of BRISP gave a considerable contribution.

Samples such as liquid metals, hydrogen-bonded liquids, and quantum liquids have been successfully investigated over the years. The kinematic range (Q,E) accessed by various techniques can be analysed in the figure aside, where the extended blue zone is the one covered by specific neutron techniques. The one probed by BRISP is indicated in red.

BRISP @ ILL