Experiments Exploiting Central Facilities
The centre makes considerable use of beams of radiation produced at national facilities such as ISIS and Diamond. ISIS generates beams of neutrons and muons, and Diamond is a synchrotron that produces high-intensity beams of electromagnetic radiation of x-ray wavelengths and larger.
4 January 2016
Neutron beams used in materials research have wavelengths and energies that are characteristic of the length and energy scales of the intertomic distances and atomic vibrations of crystalline and disordered materials. Thus they have a long tradition in applications for the study of structure of the structure and dynamics of materials. The centre is a significant user of neutron beams for materials research, including diffraction for the study of crystal structures, total scattering for the study of local structure, and inelastic scattering for the study of lattice dynamics. We were principle investigators on the project to build the Merlin spectrometer, and have co-led the work to develop methods for analysis of total scattering from disordered crystalline materials.
ISIS also produces beams of muons, which are used in materials research because the muon is a sensitive probe of local magnetic structure.
Synchrotron beams provide complementary information to neutrons. In diffraction, the coupling of individual atoms to X-rays and neutrons is very different, often allowing diffraction studies to yield different information from the same material. One technique that is unique to x-rays is absorption spectroscopy, where the Fourier transform of the fine structure in absorption profiles can yield direct information about local structure. The important advantage in this technique is that it is element-specific; conventional total scattering experiments that provide information about local structure obtain a sum over all atoms rather than separating the local structure associated with different types of atoms, but on the other hand have the advantage of extending to larger interatomic distances.