Neutron scattering and other research
How is ANSTO neutron scattering work undertaken?
Adjacent to the OPAL reactor is the Bragg Institute, which has a worldwide reputation for excellence in neutron beam and X-ray science, and is one of ANSTO's most successful and fast growing institutes. The Bragg Institute's neutron beam instruments (see below) are used to solve complex research and industrial problems in physics, chemistry, materials science and engineering, life and Earth sciences.
The Bragg Institute is named after the 1915 Australian Nobel prize winners father and son William and Lawrence Bragg.
What are neutrons?
A neutron is one of the fundamental subatomic particles that makes up matter. They are only one-thousandth the size of the smallest atom, yet they can easily travel through centimetres of solid steel. This uncharged particle with a mass slightly greater than that of the proton found in the nucleus of every atom except ordinary hydrogen, neutrons are the links in the chain reaction in a nuclear reactor.
Neutron guides
Neutrons produced in a reactor can be used for research. The best way to use neutrons for any scientific investigation is to conduct them in a special tube or guide away from the root to instruments, on which you can do your neutron research.
Attached to OPAL is a neutron-beam transport system consisting mainly of supermirror guides. Neutron supermirrors are a device for transporting, bending, and focusing neutron beams. Neutrons are reflected off the surfaces of the inside of these guides, fabricated using nickel and titanium, and directed from the reactor building into the adjoining building where the instruments are located.
The use of neutron beams can reveal to scientists information about the structure of what it is they are sampling (via interactions with the nucleus of the samples atoms). Basically OPAL is a neutron factory and the technology of the thermal and cold beam lines ensures ANSTO's position at the forefront of the use of this cutting edge technology.
What is neutron scattering?
Neutrons can be used to look at for example; blood cells, plastic, paper, magnets, chocolate, aircraft components and many more. If it has an atomic structure, our understanding of it can be improved by scientists using neutrons. Neutrons generated in research reactors are scattered by atoms in the material being probed. The scattering pattern reveals the sample's molecular structure. This technique is called neutron scattering.
Particle accelerators
Accelerator Mass Spectrometry (AMS) is the only technique able to determine extremely low concentrations of long-lived radioisotopes in small (mg) environmental samples. The best known application is the AMS radiocarbon dating method. Other applications include climatology, nuclear safeguards and geological exposure dating.
ANSTO has three accelerators. The Australian National Tandem Accelerator (ANTARES) is the only accelerator anywhere in the world accredited by the IAEA for use in Nuclear Safeguards work. ANSTO is sent samples from various countries to test for the minute traces of radioactive releases that would indicate the presence of a clandestine nuclear weapons program.
The accelerators are also used in carbon dating of historical artefacts and objects from the natural world, as well as in such applications as authenticating wine vintages. ANSTO also uses radiocarbon dating to accurately determine the growing season of illicit drug samples. There are also applications in a wide range of environmental applications, such as dating ice cores to research climate change in the southern hemisphere. ANSTO's accelerator-based services and research and development are provided nationally to all universities and commercially to Australian industry, local councils, and other research organisations, and internationally through IAEA.
ANSTO’s neutron-beam instruments are:
Echidna – a high-resolution powder diffractometer that can accurately resolve complex atomic and magnetic structures of powders and is used, amongst other things, for research into batteries and creating better building products.
Koala – a laue diffractometer that can look at crystal structures. Koala’s capability to precisely locate individual hydrogen atoms plays an important role in the understanding and development of catalysts, pharmaceuticals and energy materials.
Kowari – a residual-stress diffractometer that looks at stresses in materials such as jet engines or gas pipes or investigating failures of wheels and rails.
Platypus – a reflectometer that can study surfaces and interfaces of thin films, membranes and surfaces that interact with air or liquid. It is not only useful for studying biological materials such as membranes or polymers, but also for studies of thin-film magnetic devices such as data-storage films in hard drives.
Quokka – a small-angle neutron scattering instrument that investigates the structure of materials on the nanoscale. Quokka is used for studying materials such as polymers, superconductors, porous materials, geological samples, alloys, ceramics and biological molecules such as proteins and membranes.
Taipan - a thermal triple-axis spectrometer used to measure neutron inelastic scattering, which is a key technique for the measurement of excitations in materials. These measurements provide information on the forces between atoms, or interactions between magnetic moments.
Wombat – one of the most powerful powder diffractometers in the world. It can detect millions of neutrons to produce data on the structure of material in a matter of milliseconds: we can watch chemical reactions as they happen. Its focus includes studying novel energy-storage materials and molecules for drug-delivery.
Sika (under construction) - a cold-neutron three-axis spectrometer suited to study problems in low-temperature physics, like understanding novel materials such as superconductors, magnets and strange metallic states.
Pelican (under construction) - a time-of-flight spectrometer and part of the inelastic neutron-scattering suite for the study of molecular dynamics and diffusions in hydrogen-bonding and storage systems, catalytic materials, cement, soils and rocks, looking at hydration process and ion diffusion.
There are plans to extend the instrument menagerie further over the next few years; for example an ultra-small-angle scattering instrument investigating structure on the microscale level, and a beryllium-filter instrument for the study of hydrogen’s behaviour in hydrogen-storage material.