Tran - Interactions of X-rays with matter, optical coherence and X-ray imaging
Our research covers both fundamental and applied fields in X-ray science. Together with our collaborators from the University of Melbourne, the Australian Synchrotron, Photon Factory Japan, and Advanced Photon Source and Stanford University in the United States, we have developed the X-ray Extended Range Technique to quantify the interaction cross-sections (photo-absorption, scattering, and fluorescence) between X-rays and a range of important elements and compounds. The results have been used as benchmarks to critically investigate alternative theoretical calculations of atomic processes. We are now developing the technique for X-ray Absorption Fine Structure studies.
Our group has also played the leading role in an international collaboration determining the complete coherence property of synchrotron X-ray beams, which is important for the development of advanced light sources for frontier scientific research around the world. We have extensive experience in various forms of propagation-based X-ray imaging, and are developing quantitative full field imaging techniques using polychromatic X-ray sources. The techniques promise great opportunities for critical X-ray-based research to be conducted using table-top laboratory X-ray sources.
Research areas
Elemental contrast full-field imaging using polychromatic X-ray sources
The spatial distribution of individual elements in compound samples has been the subject of extensive interest in many important fields including materials science and engineering, mineral sciences, nanotechnology, medical imaging, archaeology, and so on. However, attempts at quantitative imaging using polychromatic X-ray beams produced from sources available in most small to medium research institutions have been limited.
We are developing an elemental contrast imaging technique using polychromatic X-rays. The technique will be applied to achieve three dimensional elemental contrast imaging of defects in alloys and implants. We will investigate methods in which the techniques developed in the project can be implemented using the broad spectrum X-ray sources.
Investigation of dynamic systems using X-ray coherence
Extracting the maximum possible information conveyed in optical fields is important. Partially incoherent fields contain far greater information capacity compared to fully coherent fields, such as lasers. A fundamental limitation of current imaging techniques is the lack of a technique that is capable of extracting the enormous amount of information carried in partially optical wavefields. Our research aims to develop state-of-the-art X-ray imaging technique in which dynamic information about an object encoded in a partially incoherent wavefield can be decoded or reconstructed.
Interactions of X-rays with matter
This research involves critical study of atom-photon interactions by accurate determination of the complex atomic form factors. Photon-atom interaction cross-sections are important in many fields of fundamental and applied physics. As many uncritical applications are well established, researchers and users outside the field have assumed that experiment and theory have converged with no further critical goals in this area. This assumption is seriously flawed for all elements in many energy regions.
We have developed a novel experimental technique called the X-ray Extended Range Technique (XERT) for accurately determining these cross-sections. The project will apply XERT in the investigation of the angular dependence of X-ray scattering and fluorescence using polychromatic sources.
Group leader