Neutrons are subatomic particles released in nuclear fission. They have no electrical charge and penetrate materials more effectively than X-rays. This ability makes neutrons an especially useful tool in industrial materials analysis.
Neutron scattering is a technique used to find answers to fundamental questions about the structure and composition of materials used in medicine, mining, transportation, building, engineering, food processing and scientific research.
Neutrons penetrate most materials to depths of several centimetres. In comparison, X-rays and electrons probe only near the surface.
X-rays and electrons are scattered by atomic electrons whereas neutrons are scattered by atomic nuclei. This results in a number of differences, perhaps the most important being in the scattering from light elements. Whereas one electron on a hydrogen atom can be hard to find by X-ray or electron diffraction, the hydrogen nucleus scatters neutrons strongly and is easily found in a neutron diffraction experiment.
Neutrons, though electrically neutral, act as small magnets, and are uniquely powerful in the atomic scale study of magnetism.
Neutrons are also uniquely suited to the study of the dynamic processes (e.g. thermal vibrations) in solids.