Convective instabilities in liquid crystals observed by neutron scattering

Eventually conventional neutron spectroscopy has to fail when the neutron passage time over a correlation range becomes shorter than the characteristic time that we are trying to measure. We shall discuss below the merits of a complementary method, a real-time method, which in principle works when the conventional method fails. It seems worthwhile to seriously consider this method as much of the scientific interest moves to mesoscopic and to nonequilibrium systems. We have used this method for some years in the study of convection instabilities in nematic liquid crystals. Probably we have discovered more problems than we have solved, but perhaps a presentation of them is justified at a workshop where we are discussing the problems of tomorrow