Expanding Infrastructure at Monash
New Source of Bright Ideas for Materials Science
Australia’s newest major national science facility, the world-class Australian Synchrotron, is open for business in Melbourne opposite the Clayton campus of Monash University.
Synchrotron director Prof. Robert Lamb says the facility offers a wide range of analytical and imaging techniques that are well suited to materials science applications.
The synchrotron’s individual ‘beamlines’ filter and direct selected wavelengths into customised experimental facilities, enabling an impressive array of non-destructive, high-resolution, rapid, in-situ, real-time imaging and analysis techniques. These can generate elemental, structural and chemical information from diverse sample types ranging from biological to industrial materials and minerals. The unique properties of synchrotron light mean that experimental results are far superior in accuracy, clarity, specificity and timeliness to those obtained using conventional laboratory equipment.
Operational beamlines include protein x-ray crystallography (PX), infra-red spectroscopy, powder diffraction, soft x-ray spectroscopy and x-ray absorption spectroscopy. The PX beamline is already in high demand for molecular biology research, rational drug design and structural genomics, and a second PX beamline is under construction. Along with the second PX line, the remaining three of the initial suite of nine beamlines will be up and running by the end of 2008. These are the SAXS WAXS (small angle and wide angle x-ray scattering), microspectroscopy, and imaging and medical therapy beamlines.
The synchrotron’s infrared beamline enables users to locate and analyse individual components in samples just a few micrometres across. Uses include microanalysis of composite materials, characterisation of surface contaminants, studies of minerals at very high pressure, forensic investigations, and band-gap studies of semiconductor materials and non-linear optical materials. A separate branch of the IR beamline can be used to characterise gas phase samples.
The powder diffraction beamline provides high-resolution x-ray data from polycrystalline materials such as pharmaceuticals, zeolites, mineral processing products, solid metal oxides, and short-range ordered materials such as those that exhibit negative thermal expansion. It can also measure strain, phase and texture for engineering-related research. Powder diffraction is ideal for structural investigations where large single crystals are not available and for studying rapidly-changing processes.
The powder diffraction beamline provides high-resolution x-ray data from polycrystalline materials such as pharmaceuticals, zeolites, mineral processing products, solid metal oxides, and short-range ordered materials such as those that exhibit negative thermal expansion. It can also measure strain, phase and texture for engineering-related research. Powder diffraction is ideal for structural investigations where large single crystals are not available and for studying rapidly-changing processes.
Soft x-rays are well-suited to characterising surfaces, thin films and near-surface interfacial layers. The soft x-ray beamline is used for research ranging from fundamental studies in solid state physics and nanotechnology to applied chemistry problems in catalysis and coal combustion. Full polarisation control of x-rays makes it possible to study magnetic materials through magnetic linear and circular dichroism.
X-ray absorption spectroscopy (XAS) is widely used in the biological, chemical, earth, environmental, materials and physical sciences and engineering. Applications include studies of metal complexes and mechanisms associated with the formation of ore metal deposits, characterisation of ion-implantation-induced disorder in semiconductor substrates, and investigation of novel properties exhibited by materials at the nanometre scale (including semiconducting and metallic nanoparticles). XAS techniques are only available at synchrotrons.
SAXS WAXS (small angle and wide angle x-ray scattering) techniques are used in the life and physical sciences to study a variety of samples and systems, including muscle and membrane structures, chemical reactions and catalysts, advanced materials and food components. SAXS and WAXS complement nuclear magnetic resonance, electron microscopy, light scattering and small angle neutron scattering (SANS) techniques. The synchrotron beamline can collect SAXS and WAXS data separately or simultaneously. Materials science applications include analysis of solid surfaces, thin films and liquid surfaces, as well as in situ measurement of dynamic processes such as polymer processing, mineral processing and crystallisation.
Synchrotron microspectroscopy uses x-ray absorption and fluorescence emission spectroscopy to obtain elemental, structural and chemical information from a very diverse range of samples at submicron resolution. Microprobe materials science applications include studies of surface corrosion and wear mechanisms, photovoltaic materials, fuel cell electrodes, polymer seeding and crystallisation, and the impact of impurities and contaminants on recycling processes. Physical science applications include studies of advanced materials, ceramics, nanomaterials, composites, chemical reactions and catalysts, as well as forensic investigations and mineral exploration and beneficiation work.
The imaging and medical therapy beamline will have numerous biomedical, materials science and industrial applications. A major focus will be the development of microbeam radiation therapy techniques based on the observation that an array of very thin x-ray beams can destroy a tumour Materials science applications include the study of membranes for use in advanced fuel cells, investigation by micro-CT (computer tomography) of micro- and nano-structured devices for use in automotive applications, and examination of advanced materials during and after exposure to mechanical and environmental stresses
As a national facility, the synchrotron is independently operated by the Australian Synchrotron Company Ltd. Construction was financed by the Victorian Government and the facility’s operations are jointly funded by the Victorian and Commonwealth governments. The New Zealand Government, the state governments of Western Australia and Queensland, leading Australian universities, the Association of Australian Medical Research Institutes, CSIRO and ANSTO have provided funding for the development of beamlines.
Access is by peer-reviewed application and is free if results are published in the open literature. Synchrotron services are also available on a confidential basis to fee-paying clients.
Director Rob Lamb says that by the end of 2009, the synchrotron will be the largest scientific user facility in the southern hemisphere. He encourages prospective users to contact synchrotron staff to discuss their research objectives.
For more information, visit www.synchrotron.org.au or phone +61 3 8540 4100.
| Kia Wallwork on the powder diffraction beamline |
Bruce Cowie on the soft x-ray beamline |
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The Monash Centre for Electron Microscopy
MCEM is a central university research facility which conducts research in electron microscopy and atom probe microscopy, and provides advanced instrumentation, expertise and training in electron microscopy and atom probe microscopy. MCEM has recently moved into its new, ultrastable building, abutting Materials Engineering and Physics on the Clayton campus which has been designed to optimise instrument performance by minimising mechanical, thermal, electromagnetic and acoustic interference.
Four new microscopes are under installation in the new building, in addition to MCEM’s five existing instruments. These include a “double-aberration-corrected field emission gun transmission electron microscope”, which is one of the highest resolution microscopes in the world with a spatial resolution of better than 0.1nm; a modern field emission gun scanning electron microscope, which is fitted with specialist detectors for looking at grain composition and orientation relationships; and a 3-D atom probe with superior mass resolution and vastly improved acquisition rate over Monash’s current atom probe.
MCEM supports a wide variety of disciplinary and interdisciplinary research projects, covering topics from corrosion to catalysis, optics to superconductivity, alloys to ceramics, polymers to biomaterials and microelectronics to nanotechnology.
Further information about MCEM is available at: www.mcem.monash.edu.au.
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FEI Quanta 3D FEG.
A major item of infrastructure for the materials research community at Monash is anticipated to arrive in September. The equipment, known as a Dual Beam Focused Ion Beam, is the result of a successful ARC bid led by Nick Birbilis, along with the support of the Monash Centre for Electron Microscopy (MCEM), Deakin University, and RMIT University.
Better known as the FEI Quanta 3D FEG, this instrument can be thought of as a conventional high resolution SEM (scanning electron microscope); however it also has an additional column that produces a Focused Ion Beam (hence the name, Dual Beam Focused Ion Beam).
The Ion beam allows for very localized (nanoscale) material milling and removal in-situ, allowing site-specific milling and conversely, site-specific material deposition. This will also permit for the preparation of site-specific TEM specimens, along with specimens for analysis via atom probe and even Synchrotron. We envisage all areas of active research in the Department will be enhanced by this new capability, including the Light Alloys team, to Surface Analysis, to Biomaterials, Ceramics, Corrosion and Nanomaterials.
The new instrument is complete with comprehensive specifications allowing it to be capable, at a minimum, of :
- High resolution SEM (Field emission source)
- High speed / high current FIB allowing most rapid material removal rates available
- State of the art EDXS analysis
- Ultra High speed Electron Backscattered Diffraction Analysis (EBSD)
- Environmental mode (i.e. so capable of working in High, Low, and Ultra Low vacuum at humilities up to 100%RH)
- Ion imaging
- In situ micro-manipulation
- Automation for Serial sectioning, AutoFIB (i.e. TEM sample prep), Slice and View, and the ability to allow for 3D characterization and reconstruction.
We look forward to sharing the good news of instrument commission in future newsletters, together with some highlights from active research utilizing this equipment.
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New addition to the Atom Probe Laboratory
A new 3-D atom probe, the latest Oxford nanoScience model, equipped with a modern detector (delay-line detector) that can encode multiple ions arriving at the same time at the detector, arrived in Monash in December 2007. This new atom probe has much higher mass resolution and faster data acquisition rate than the existing atom probe (Kindbrisk model, purchased in 2000), and the operation is more user-friendly. The high mass resolution makes it suitable for analysing complex alloys which may have some peaks close to each other on the mass spectrum. The frequency of the pulsing voltage on this new atom probe can run up to 20kHz, which allows us to collect about one million atoms in one hour. This is much faster than the existing atom probe which runs at 1.5kHz. The new atom probe has been successfully commissioned since January 2008.
The principle of the 3-D atom probe technique sounds very simple. When a high enough positive voltage is applied on a conductive material (metal or alloy), the atoms on the surface will be ionized and projected to the cathode, called field evaporation. By using a combination of time-of-flight mass-spectrometer and position-sensitive detector, the species and the position of the evaporated ion in the sample can be recorded and re-constructed in 3 dimensions using a computer.
This 3-D atom probe technique is very powerful in determining the composition distribution with atomic resolution. It is the only technique that can be used to analyse the compositions of nanometer scale phases in alloys. We use it to determine the compositions of the constituent phases in the high performance SmCo-based permanent magnets in which a platelet phase is just a few nanometers thick. Other projects, such as the clustering behaviour during ageing in light alloys (Al-based alloys etc.), the carbon clustering behaviour in ferritic steels and so on, are also relying on this unique technique for detailed analysis of the composition distributions. The timely addition of this new atom probe to our laboratory reinforces our capacity for characterizing the nanocrystalline structure and nanocomposite materials.
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