A suite of seven neutron beam instruments is available, with a further six instruments in design or construction. A broad selection of sample-environment equipment is also available, including cryostats, furnaces, magnets, pressure cells, stress rigs, shear cells and electrochemical apparatus. We can also offer some help with modelling in order to understand neutron-scattering data. Molecular deuteration of samples for neutron-scattering studies is also available through the National Deuteration Facility.
The ANSTO User Office assists users with the various security and administrative processes required for our visitors.
Neutrons have many properties that make them useful for studying atomic and molecular structures ranging in size from one nanometre to several hundred nanometres. They can be considered as particles or waves, with wavelengths comparable to the interatomic distances found in solids and liquids. Their energies are of similar magnitude to those associated with molecular vibrations.
Cold (slow) neutrons have low energy and long wavelengths. Thermal neutrons have intermediate energy and wavelengths. Hot (fast) neutrons have high energy and short wavelengths.
Neutron techniques can use a single wavelength or a range of wavelengths. Neutrons have some advantages over X-rays as tools for determining the structure of both molecules and the arrangement of molecules within materials. For example, neutrons can be used to investigate and provide unique information about semiconductors and magnetic materials used in computers.
Unlike electrons and protons, neutrons have no electric charge. This means that they can reveal the position of the nucleus itself, which makes up a tiny fraction of the volume of an atom. In contrast, X-rays are scattered by electrons and reveal the position of the electron clouds. Heavy atoms scatter X-rays more effectively than light atoms. Neutron scattering varies from nucleus to nucleus.
X-rays cannot be used to determine the positions of hydrogen atoms or of light atoms in close proximity to heavy atoms but neutrons can. Isotopes (atoms of the same element with different numbers of neutrons) such as hydrogen and deuterium can readily be distinguished by neutron scattering but not by X-rays. Scientists can therefore substitute deuterium for hydrogen in polymers and biologically important molecules to highlight particular features by neutron scattering.
As neutrons scatter from nuclei and not electrons, they are highly penetrating. This makes it possible to study samples deep inside large pieces of equipment (such as aircraft engines), and inside vessels that have different conditions of pressure, temperature and environment.
Neutrons behave to some extent like tiny bar magnets and can therefore be used to investigate the magnetic properties of materials such as superconductors and computer memories.
When a neutron beam hits a sample, 80 to 90 per cent of the neutrons pass through the sample, some 'scatter' and a very small number are absorbed. The angle at which the neutron beam hits the sample affects the 'scattering' and, hence, the type of information that can be gained.
Most neutron scattering techniques are based on elastic scattering, in which the energy of the scattered neutrons does not change. Inelastic scattering, in which the energy of the scattered neutrons changes as a result of interaction with the sample, is used to investigate molecular vibrations and magnetic properties.