A free neutron interacts with the atomic nuclei that make up matter. Depending on its momentum or wave vector, its energy and possibly its spin, different types of interactions can occur.
Different types of interactions
The neutron is captured by the nucleus of an atom.
The neutron is scattered without losing energy.
The neutron exchanges part of its energy with the material.
The neutron excites the motions or internal states of the material.
Measuring neutron interactions
Measuring variations in the neutron wave vector Q and/or neutron spin provides information about the properties of the studied material.
✔ The neutron wavelength is close to the dimensions of the structures present in the material.
✔ The neutron energy is comparable to the energies associated with atomic motions and material excitations.
Neutrons adapted for studying matter
Neutrons with wavelengths ranging from 1 Å to 15 Å, corresponding to energies between 0.4 meV and 80 meV, are particularly suitable for exploring matter at the atomic scale.
Neutron techniques
Reflectometer
Diffractometer
SANS
Spectrometer
Neutron imaging
Depending on the properties being investigated, different instruments are used to study crystal structures, nanostructures, excitations, interfaces and magnetic properties of materials.