But man's innate curiosity has made it necessary to invent instruments that let us see with even greater clarity. Telescopes allow us to see deep into outer space and microscopes allow us to see the very small. To see yet smaller objects, such as the arrangements of atoms and molecules that make up the very substance of our world, we have to be much more inventive. We must make use of invisible radiation, such as x-rays and neutrons, devising methods of shining such radiation onto materials, and of interpreting and understanding the complicated patterns of radiation that is scattered back.

Alone among such invisible radiation, the neutron is a particularly gentle probe of materials. A sub-atomic particle that behaves as both a particle and a wave, the neutron penetrates deep into materials revealing, at the very same time, a complete and precise picture of where the atoms are and how the atoms are moving and vibrating. And this is crucially important. On the one hand it enables us to understand the material from which our world is made; why glass breaks, why rubber bounces, why iron is magnetic and why drugs work. On the other hand it provides us with the information we need to modify and optimise existing materials and to invent and develop new materials to help meet the ever-growing demands of our increasingly technological society. (more information to be found in the section "The main advantages of neutrons").

When neutrons impact upon a metal sample, they are scattered by the atoms inside that metal. Detectors behind the sample measure the neutrons' deflection angle. From these data, researchers calculate a scattering pattern. Here weak scattering is shown in blue, while red and white denote strong neutron scattering intensity. Atoms are located at the white and red "dots."


Read other interesting explanations:
Why Neutrons?
(Geesthacht Neutron Facility - GeNF)

Neutrons, a universal toy for physicis - FRM II, Germany

Why use neutrons? - ILL, France