X-ray Science in Australia
By Keith Nugent
2007 is an exciting year for Australian science. It has seen the opening of two world-class facilities: the new OPAL research reactor in April 2007 and the Australian Synchrotron in July 2007. It is therefore timely to look at the science that will be done at these facilities and their potential impact on science in the region. Here we look at the state of Australian physical science using x-rays in 2007. We can be sure that the scope of this work will massively expand as the Australian Synchrotron progressively takes its place at the centre of Australian science.
X-ray science in Australia has a long history. Indeed the x-ray work of the elder Bragg began at the University of Adelaide under long-distance mentorship from that other famous antipodean, Ernest Rutherford. Australian physics has had a presence in x-ray physics since that time with a particular strength in x-ray crystallography.
The Australian x-ray science community has long been lobbying for access to synchrotron facilities. The lobbying by the scientific community began to have real effect in 1992 when Australia established a facility at the Photon Factory in Japan known as the Australian National Beamline Facility. This facility was a major success and demand for beam-time rapidly exceeded supply so that, in 1994 negotiations commenced for Australian participation in the Advanced Photon Source project at the Argonne National Laboratory. Funding for this project was approved in 1995 and the Australian Synchrotron Research Program (ASRP) was established. The ASRP provides extensive access to APS and Photon Factory facilities, and after 2002 soft x-ray facilities at the National Synchrotron Radiation Research Centre in Taiwan.
The ASRP sponsored growth led the Australian community to lobby for a local third-generation facility. After a period of debate, discussion and economic analysis, the Victorian government committed in 2001 to devote $A157M to the building of third-generation facility located in Clayton, a suburb of Melbourne, Australia’s second largest city. The research community, including universities from all states, the Commonwealth Scientific and Industrial Research Organisation (CSIRO), the Australian Nuclear Science & Technology Organisation (ANSTO) and the New Zealand government, all provided enthusiastic support as well as an additional $50M for the construction of beamline facilities. It has been claimed that the Australian Synchrotron has attracted more broad-based support from Australia’s scientists than any other research project in Australia’s history.
The design and construction of the Australian Synchrotron, with a circumference of 216m and a beam energy of 3GeV, commenced in 2003. An initial nine beamlines were planned and funded. Commissioning of the first five of the beamlines commenced in June, 2007. Open user operation will commence in late 2007. In May 2007 the Federal government announced $A50M of operating funding for the facility over the next five years and in June 2007 this sum was matched by the Victorian government. May 2007 also saw Professor Rob Lamb, an expert in surface science from the University of New South Wales, appointed as the inaugural Science Director for the facility. In June a strategic plan for the ongoing development of science with synchrotrons, Accelerating the Future, was launched. The pieces were now in place for the Australia Synchrotron to become a pivotal piece of scientific and technological infrastructure for Australia for the foreseeable future.
With the ASRP, Australian science has come to depend on access to a wide range of synchrotron facilities and it is simply not possible for a single facility to meet all of its needs. The Australian Synchrotron is designed to meet as much of the demand as possible and also particularly serve the protein crystallography community. As such, it is anticipated that the Australian Synchrotron will meet in excess of 90% of the Australian demand for synchrotron time, with the remainder being met by an ongoing access to selected overseas facilities including fourth-generation sources.
Australia has particular strengths in the development of imaging methods and in materials science. A significant amount of experimental and theoretical work on the fundamentals of propagation-based phase-contrast imaging and on the method of diffraction-enhanced phase-contrast imaging has been done by groups at CSIRO, led by Steve Wilkins, and at the University of Melbourne led by Keith Nugent and in collaboration with scientists at the Advanced Photon Source. Rob Lewis and collaborators at Monash University and at SPring-8 have been applying these methods to, among other things, the study of the aeration of the lungs of new-born wallabies. Andrei Nikulin, also of Monash University, has another very active collaboration with scientists at SPring-8 where he is developing diffraction and phase-recovery techniques for the examination of multilayer superstructures
The development of coherence based methods has been extended to the field of coherent diffractive imaging via funding from the Australian Research Council to establish Centre of Excellence for Coherent X-ray Science, directed by Keith Nugent. This centre includes physicists, chemists and biologists from four universities and CSIRO and will explore the application of coherent x-ray methods to problems in the biosciences. The project includes the development and application of high-harmonic-generation laser based soft x-ray sources and the development of a theoretical understanding of the interaction of intense coherent fields with molecules. The work of the centre will impact the goal of the international x-ray free-electron laser community of imaging a single biomolecule at atomic resolution using an ultrashort coherent x-ray pulse.
The role of materials physics and chemistry is particularly important given the almost simultaneous opening of the OPAL research reactor based at ANSTO in Sydney. Ian Gentle of the University of Queensland uses both x-ray and neutron reflectivity to probe the properties of interfaces. John White of the Australian National University works on the fabrication of molecular thin films and uses x-rays and neutrons for the subsequent material characterization and development of applications. Mark Ridgway of the Australian National University is exploring the processing and characterisation of semiconductor materials using x-ray and neutron small angle scattering and reflectivity experiments. Rob Lamb, now at the Australian Synchrotron and the University of Melbourne, studies the surfaces of thin films and materials using a range of surface sensitive analytical techniques including x-ray photoelectron spectroscopy, secondary ion mass spectroscopy, small angle scattering, synchrotron x-ray absorption spectroscopy and wettability. David Jamieson of the University of Melbourne and Chris Ryan of CSIRO are bringing their long experience in proton microprobe work to bear on the construction of a microprobe beamline at the Australian Synchrotron, and Chris Chantler of the University of Melbourne is developing extremely high precision measurement methods for the characterisation of the interaction of x-rays with matter. Andrea Gerson of the University of South Australia looks at interfacial and solid state structure and reaction mechanisms in relation to crystallization phenomena within the petrochemical, Bayer and pigment industries. Andrea is currently the Lead Australian Scientist for the Australian-Canadian synchrotron collaboration that focuses on the development of industrially useful synchrotron end-stations at both the Canadian Light Source and the Australian synchrotron. Pete Hammond of the University of Western Australia has been using UV radiation from Sincrotrone Trieste to explore atomic physics, and Robert Leckey, John Riley and colleagues at La Trobe University are continuing their exploration of Fermi surfaces through their long standing collaboration with BESSY in Germany, a collaboration that moved to BESSYII in 2003.
Australian x-ray science is at a dynamic stage, and there is a great deal of excitement surrounding the new facility. Australia’s national strengths will be reflected in the development of the Australian Synchrotron in the coming years, while we continue to nurture our extensive international collaborations and linkages.