Prosessora Maria Luísa Carvalho - Ext.: 10171
Professora Ana Fonseca - Ext.: 10504
António M. dos Santos (Diffraction Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge Tennessee, USA
Titulo: State of the Art Techniques in Neutron Scattering: Research on Solid State Physics, Chemistry and Geophysics
Neutron scattering is a unique tool in the study of the chemical and physical properties of materials. The absence of electrical charge, the presence of spin and the possibility of isotope discrimination, allows insights on problems mostly inaccessible through other techniques. These include structural studies of compounds containing light elements, the magnetic structure of materials, the non-destructive inspection of engineering parts and the determination of lattice dynamics at the atomic length scale. However, unlike other sources of radiation readily available in the home laboratory, such as visible light or X-rays, neutrons can only be produced, in useful amounts for scientific research, in dedicated large-scale facilities, such as nuclear reactors or through spallation. The Oak Ridge National Laboratory is a unique user facility in that it houses both types of neutron sources, the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR), making it arguably the leading laboratory in the world for neutron scattering research. The SNS’s suit of instruments is now almost complete, with some instruments having already produced groundbreaking research. Here we will illustrate the novel possibilities of neutron scattering experiments, afforded by these new facilities, by presenting some recent scientific results of research performed at SNS, namely examples of compression mechanisms of amorphous solids, magnetic phase diagrams in lanthanides, phase competition in manganites and structural studies of clathrate hydrates. These examples will highlight how the use of the SNS capabilities is already resulting in an exciting science portfolio.