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Wombat shows its grunt |
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Eight of ANSTO's neutron scattering instruments are named after Australian animals.
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Part of the team that brought Wombat on-line surround the instrument.
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When the Prime Minister opened the Australian Nuclear Science and Technology Organisation's (ANSTO) OPAL research reactor in April, like many visitors he was beguiled by the blue glow of Cerenkov radiation emanating from the reactor core.
But ANSTO's neutron scientists are more excited about the potential of the $400 million reactor's neutrons to solve problems and pursue opportunities in many areas of research and industry.
At the end of February, ANSTO's second neutron beam instrument - named Wombat because of its 'grunt' - went on-line for the first time. In honour of the new reactor, Dr Andrew Studer, the scientist in charge of the instrument, selected an opal gem as an early test material for the neutrons to penetrate.
The High Intensity Powder Diffractometer cost $5 million to build and boasts one of the world's finest neutron detectors. It has the power to detect a million neutrons a second and to produce data on the structure of materials in milliseconds. The detector is only the second of its kind in the world.
"Australia is exceptionally lucky to have this instrument," said Andrew. "Wombat is both fast and powerful. Fast because of the detector and powerful because of OPAL itself.
"There's an old saying in neutron diffraction," Andrew said. "You've got to have grunt at the front. There's no point in being able to count a million neutrons a second if they're not there in the first place.
"This is where the way OPAL was designed and built becomes so important," explained
Andrew. "OPAL has a series of guides - sort of like optical fibres for neutrons - that transport neutrons from the reactor core out to our instruments in the Neutron Guide Hall. This technology allows us to put tremendous neutron fluxes onto our samples.
"In our first real measurement on a standard sample we counted more than a hundred thousand counts a second of real diffraction data," he said. "The instruments at HIFAR (the old reactor) could get a useful pattern in a minimum of about a quarter hour. Now we get impatient if we have to wait more than about 15 seconds.
"Wombat will also let us run in-situ experiments in real time," explained Andrew. "For example, if you want to know at the atomic level how a metal will respond if rapidly heated to 900 degrees, or how a piezoelectric material changes structure when put in an electric field that varies with time, Wombat will show you."
Wombat is also very useful for doing measurements on small samples. For example, one of the test samples being measured is a material created in a high temperature pressure cell meant to simulate conditions in the earth's mantle (roughly 600 kilometres straight down).
Initial trials show that Wombat will have no trouble measuring the tiny 25 milligram sample.
In this case the sample was prepared 'off-line', but Wombat has the opportunity to lead the world in performing in-situ measurements under extreme conditions.
"One of the great opportunities we have is to measure materials under extremes of high or low temperature, pressure or magnetic field," said Andrew. "The challenge of the future is that, more and more, users want to do combinations of these, so they can see how materials act in the real world with numerous factors acting on the materials."
As well as measuring tiny samples, the penetrating power of neutrons makes them very useful for looking at large samples. For example, in environments which simulate industrial processes.
"This type of information is crucial for refining manufacturing processes or knowing how to better extract minerals from rock, because we can see what is happening atomically during the production process.
"The refining of some manufacturing processes tends to be a little hit or miss, as what happens to materials at the atomic level during manufacturing has not been accurately measured before. In Australia, this is about to change, thanks to this technology," said Andrew. |
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Wombat will also play a major role in the search for a material that can successfully hold significant quantities of hydrogen, which in turn could be used to provide clean power. For example, batteries in laptops use hydrogen-absorbing metal, known as a hydride, for power. These batteries are heavy and don't last long between recharges, so scientists want to develop a lighter material that can also hold more energy and last a long time. Wombat can play a major role in developing such a material |
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Wombat was a real team effort - jobs involved painstakingly aligning the guides, polishing the floors, designing and assembling the components, cabling everything up, writing the code and managing the project. |
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