Why use neutrons?
Neutrons scatter from materials by interacting with the nucleus of an atom rather than the electron cloud. This fact confers specific properties that make of neutron beams an extremely versatile and unique analytical probe.
Electrically Neutral. Neutrons are non-destructive and can penetrate deep into matter. This makes them an ideal probe for biological materials and samples under extreme conditions of pressure, temperature, magnetic field or within chemical reaction vessels.
Microscopically Magnetic. They possess a magnetic dipole moment which makes them sensitive to magnetic fields generated by unpaired electrons in materials. In addition, the scattering power of a neutron off an atomic nucleus depends on the orientation of the neutron and the spin of the atomic nuclei in a sample. This makes the neutron a unique tool for determining the magnetic order.
Randomly sensitive. The variation in scattering power from one nucleus to another varies in a quasi-random manner. This means that lighter atoms are visible despite the presence of heavier atoms, and neighbouring atoms may be distinguished from each other. In addition, contrast can be varied in certain samples using isotopic substitution (for example D for H, or one nickel isotope for another); specific structural features can thus be highlighted.
Energies of millielectronvolts. Their energies are of the same magnitude as the diffusive motion in solids and liquids, the coherent waves in single crystals (phonons and magnons), and the vibrational modes in molecules.
Sites of interest
These pages are maintained by the Commission Last updated: 15 Oct 2021