New spectrometers for diffuse scattering of neutrons

The study of defects in solids can be complemented in many cases by the diffuse scattering of X-rays, neutrons or electrons to draw information about size, symmetry and position of defects. Since defect concentrations are usually very low in order to avoid interactions, the intensity problem is of major concern as well as the distinction between the interesting signal and other sources of scattering. Two neutron spectrometers are described which were specially designed to tackle these problems, one of them operating in Juelich, the other one on the HFR in Grenoble. The second one, also offering the possibility of employing polarized neutrons, is specially suited to the study of diffuse magnetic scattering