Neutron beams - Trace analysis, imaging and medicine

It's no secret that, at the atomic scale, Nature's properties are astonishing and often baffling. A priori, the study or characterization of materials using elementary particles such as neutrons is not self-evident. However, the properties of neutrons - high penetration capacity, great sensitivity to magnetism, to light elements and to the dynamics of atoms and molecules - make them a tool of choice. By learning a few basic principles, you can quickly understand how to carry out experiments and interpret measurements. Of course, the help of a specialist is essential for success and for extracting the maximum possible information, but the technique is relatively easy to learn.

The main interest of thermal neutrons is to provide information on the arrangements of atoms and molecules and their movements within matter. The majority of experiments are no longer concerned with physics proper, but with chemistry and engineering sciences. And neutron scattering is increasingly used in biology, earth sciences and even archaeology.

In this series of dossiers, two are devoted to "neutronics" as the science of neutron production: "Bases de neutronique. Neutron migration" and "Bases de neutronique. Physics and reactor calculations". In addition, J.P. Cotton's "Diffraction et spectrométrie des neutrons" [P 1 095] provides a comprehensive overview of basic theoretical concepts. In the interests of complementarity, the present dossier gives examples of applications to encourage the reader to give it a try... However, the beginning of this text provides the necessary information to enable the reader to tackle the rest without having to refer frequently to J.P. Cotton's dossier (which contains a comprehensive bibliography).

Information can also be found on the websites of France's neutron sources, the Laboratoire Léon Brillouin in Saclay (LLB) and the Institut Laue-Langevin in Grenoble (ILL) http://www-llb.cea.fr/http://www.ill.fr/ . The LLB has created a site dedicated to industrial applications: http://www-llb.cea.fr/industrie/index.html .

For further information, you may wish to read a theoretical course: the proceedings of a School on "Neutron Scattering and Materials Science":