ORCID Profile
0000-0002-6240-7143
Current Organisation
La Trobe University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Condensed Matter Physics | Nanotechnology | Nanomanufacturing | Materials Engineering not elsewhere classified | Surfaces and Structural Properties of Condensed Matter | Nanometrology | Nanophotonics | Biochemistry and Cell Biology not elsewhere classified | Condensed Matter Imaging | Condensed Matter Characterisation Technique Development | Nanoelectronics | Nanofabrication, Growth and Self Assembly
ANZSRC Socio-Economic Objective (SEO)
Integrated Circuits and Devices | Manufacturing not elsewhere classified | Expanding Knowledge in Technology | Expanding Knowledge in the Physical Sciences | Industrial Chemicals and Related Products not elsewhere classified | Scientific Instruments | Expanding Knowledge in the Biological Sciences | Fabricated Metal Products not elsewhere classified |
Related Links
Publications
Polychromatic X-ray tomography: direct quantitative phase reconstruction
Publisher: The Optical Society
Date: 26-09-2012
DOI: 10.1364/OE.20.023361
Diffraction imaging: The limits of partial coherence
Publisher: American Physical Society (APS)
Date: 03-12-2012
Characterization of the Magnesium Alloy AZ31 Surface in the Ionic Liquid Trihexyl(tetradecyl)phosphonium Bis(trifluoromethanesulfonyl)amide
Publisher: The Electrochemical Society
Date: 2010
DOI: 10.1149/1.3486119
Dynamic coherent diffractive imaging using unsupervised identification of spatiotemporal constraints
Publisher: Optica Publishing Group
Date: 19-11-2020
DOI: 10.1364/OE.408530
Abstract: Dynamic coherent diffractive imaging (CDI) reveals the fine details of structural, chemical, and biological processes occurring at the nanoscale but imposes strict constraints on the object distribution and illumination. Ptychographic CDI relaxes these constraints by exploiting redundant information in data obtained from overlapping regions of an object, but its time resolution is inherently limited. We have extended ptychographic redundancy into the spatiotemporal domain in dynamic CDI, automatically identifying redundant information in time-series coherent diffraction data obtained from dynamic systems. Simulated synchrotron experiments show that high spatiotemporal resolution is achieved without a priori knowledge of the object or its dynamics.
Simultaneous X-ray fluorescence and scanning X-ray diffraction microscopy at the Australian Synchrotron XFM beamline
Publisher: International Union of Crystallography (IUCr)
Date: 11-08-2016
DOI: 10.1107/S1600577516011917
Abstract: Owing to its extreme sensitivity, quantitative mapping of elemental distributions via X-ray fluorescence microscopy (XFM) has become a key microanalytical technique. The recent realisation of scanning X-ray diffraction microscopy (SXDM) meanwhile provides an avenue for quantitative super-resolved ultra-structural visualization. The similarity of their experimental geometries indicates excellent prospects for simultaneous acquisition. Here, in both step- and fly-scanning modes, robust, simultaneous XFM-SXDM is demonstrated.
An in-vacuum x-ray diffraction microscope for use in the 0.7-2.9 keV range
Publisher: AIP Publishing
Date: 03-2012
DOI: 10.1063/1.3688655
Abstract: A dedicated in-vacuum coherent x-ray diffraction microscope was installed at the 2-ID-B beamline of the Advanced Photon Source for use with 0.7–2.9 keV x-rays. The instrument can accommodate three common implementations of diffractive imaging plane wave illumination defocused-probe (Fresnel diffractive imaging) and scanning (ptychography) using either a pinhole, focused or defocused probe. The microscope design includes active feedback to limit motion of the optics with respect to the s le. Upper bounds on the relative optics-to-s le displacement have been measured to be 5.8 nm(v) and 4.4 nm(h) rms/h using capacitance micrometry and 27 nm/h using x-ray point projection imaging. The stability of the measurement platform and in-vacuum operation allows for long exposure times, high signal-to-noise and large dynamic range two-dimensional intensity measurements to be acquired. Finally, we illustrate the microscope's stability with a recent experimental result.
An iterative method for robust in-line phase contrast imaging
Publisher: IOP Publishing
Date: 04-04-2016
Effects of Plasma Treatment of Wool on the Uptake of Sulfonated Dyes with Different Hydrophobic Properties
Publisher: SAGE Publications
Date: 15-07-2010
Abstract: A wool fabric has been subjected to an atmospheric-pressure treatment with a helium plasma for 30 seconds. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry confirmed removal of the covalently-bound fatty acid layer (F-layer) from the surface of the wool fibers, resulting in exposure of the underlying, hydrophilic protein material. Dye uptake experiments were carried out at 50°C to evaluate the effects of plasma on the rate of dye uptake by the fiber surface, as well as give an indication of the adsorption characteristics in the early stages of a typical dyeing cycle. The dyes used were typical, sulfonated wool dyes with a range of hydrophobic characteristics, as determined by their partitioning behavior between water and n-butanol. No significant effects of plasma on the rate of dye adsorption were observed with relatively hydrophobic dyes. In contrast, the relatively hydrophilic dyes were adsorbed more rapidly (and uniformly) by the plasma-treated fabric. It was concluded that adsorption of hydrophobic dyes on plasma-treated wool was influenced by hydrophobic interactions, whereas electrostatic effects predominated for dyes of more hydrophilic character. On heating the dyebath to 90°C in order to achieve fiber penetration, no significant effect of the plasma treatment on the extent of uptake or levelness of a relatively hydrophilic dye was observed as equilibrium conditions were approached.
Micro-scale dissolution seams mobilise carbon in deep-sea limestones
Publisher: Springer Science and Business Media LLC
Date: 27-08-2021
DOI: 10.1038/S43247-021-00257-W
Abstract: Measuring the amount of carbon captured in deep-sea limestones is fundamental to understanding the long-term carbon cycle because pelagic limestones represent Earth’s largest carbon sink since the mid-Mesozoic. However, their contribution to the long-term carbon cycle is poorly quantified. Here, we use X-ray fluorescence and scanning X-ray diffraction microscopy for high-resolution chemical and structural analysis of pelagic limestone from the Paleocene Kaiwhata Formation in New Zealand. We identify densely packed diagenetic micro-dissolution seams that are invisible to light and electron-beam microscopes in most cases. Mass-balance calculations indicate that in idual seams remove ~50% of the calcite mud matrix while their bulk-s le carbon loss adds up to ~10%. The liberated carbon is trapped in situ as calcite cement or returned to the ocean during physical compaction or soft-sediment deformation. We suggest micro-dissolution structures may play an important role in the long-term carbon cycle by modulating carbon exchange between the geosphere and hydrosphere.
Shedding light on electrodeposition dynamics tracked in situ via soft X-ray coherent diffraction imaging
Publisher: Springer Science and Business Media LLC
Date: 14-05-2016
A universal measure for coherence requirements in diffractive imaging
Publisher: SPIE
Date: 26-09-2013
DOI: 10.1117/12.2027269
Rapid, low dose X-ray diffractive imaging of the malaria parasite Plasmodium falciparum
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.ULTRAMIC.2013.09.003
Abstract: Phase- erse X-ray coherent diffractive imaging (CDI) provides a route to high sensitivity and spatial resolution with moderate radiation dose. It also provides a robust solution to the well-known phase-problem, making on-line image reconstruction feasible. Here we apply phase- erse CDI to a cellular s le, obtaining images of an erythrocyte infected by the sexual stage of the malaria parasite, Plasmodium falciparum, with a radiation dose significantly lower than the lowest dose previously reported for cellular imaging using CDI. The high sensitivity and resolution allow key biological features to be identified within intact cells, providing complementary information to optical and electron microscopy. This high throughput method could be used for fast tomographic imaging, or to generate multiple replicates in two-dimensions of hydrated biological systems without freezing or fixing. This work demonstrates that phase- erse CDI is a valuable complementary imaging method for the biological sciences and ready for immediate application.
The Ag M5N45N45 Auger photoelectron coincidence spectra of disordered Ag0.5Pd0.5 alloy
Publisher: Elsevier BV
Date: 07-2003
Monitoring dynamic electrochemical processes with in situ ptychography
Publisher: Springer Science and Business Media LLC
Date: 12-03-2018
Investigation and optimization of reactive ion etching of Si3N4 and polyphthalaldehyde for two-step gray scale fabrication of diffractive optics
Publisher: American Vacuum Society
Date: 11-2019
DOI: 10.1116/1.5121760
Abstract: Nanofabrication of x-ray diffractive optics using electron beam lithography requires a complex process of electron exposure optimization and resist development. Thermal scanning probe lithography (TSPL) offers a high resolution, maskless, gray scale patterning method with reduced complexity. Thin diffractive optics with high efficiency for the extreme ultraviolet (EUV) and soft x-ray (SXR) photon range could be fabricated by combining TSPL with a single etching step if the TSPL resist, polyphthalaldehyde (PPA), can be used as an etch mask to direct-etch the pattern into a substrate using reactive ion etching. This condition critically depends on high etch selectivity between the substrate and the PPA, because TSPL resolution deteriorates as the PPA patterning depth increases beyond tens of nanometers. In this work, the authors have evaluated the etch selectivity for PPA and Si3N4 using SF6/C4F8 gases and the influence of process parameters, including gas flow rate, vacuum pressure, radio frequency bias power, and inductively coupled plasma power. The experimental results indicate that an etch selectivity of 7 (Si3N4:PPA) is achievable, and the authors demonstrate that diffractive optics for EUV/SXR can be fabricated in only two steps.
An iterative method for near-field Fresnel region polychromatic phase contrast imaging
Publisher: IOP Publishing
Date: 13-06-2017
Dynamic and spectral coherent diffractive imaging
Publisher: AIP Publishing
Date: 2023
DOI: 10.1063/5.0168513
Probing the effect of metal to ligand charge transfer on the oxygen evolution reaction in Au incorporated Co(OH)2 thin film electrocatalysts
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3TA03923D
Towards kilohertz synchrotron coherent diffractive imaging
Publisher: International Union of Crystallography (IUCr)
Date: 08-05-2022
DOI: 10.1107/S1600576722003466
Abstract: X-ray coherent diffractive imaging (CDI) techniques have been applied with widespread impact to study nanoscale material properties. New fast framing detectors may reveal dynamics that occur at millisecond timescales. This work demonstrates by simulation that kilohertz synchrotron CDI is possible, by making use of redundant information from static parts of the image field. Reconstruction ambiguities are strongly suppressed by applying a spatiotemporal constraint, obviating the need for slower methods of introducing ersity such as ptychography. The relationship between image fidelity and time resolution is investigated and shows that dynamics an order of magnitude faster can be reconstructed, compared with conventional CDI.
Correlated positron-electron emission from LiF (100)
Publisher: IOP Publishing
Date: 09-2009
Molar concentration from sequential 2-D water-window X-ray ptychography and X-ray fluorescence in hydrated cells
Publisher: Springer Science and Business Media LLC
Date: 12-04-2016
DOI: 10.1038/SREP24280
Abstract: Recent developments in biological X-ray microscopy have allowed structural information and elemental distribution to be simultaneously obtained by combining X-ray ptychography and X-ray fluorescence microscopy. Experimentally, these methods can be performed simultaneously however, the optimal conditions for each measurement may not be compatible. Here, we combine two distinct measurements of ultrastructure and elemental distribution, with each measurement performed under optimised conditions. By combining optimised ptychography and fluorescence information we are able to determine molar concentrations from two-dimensional images, allowing an investigation into the interactions between the environment sensing filopodia in fibroblasts and extracellular calcium. Furthermore, the biological ptychography results we present illustrate a point of maturity where the technique can be applied to solve significant problems in structural biology.
EIGER2 hybrid-photon-counting X-ray detectors for advanced synchrotron diffraction experiments
Publisher: International Union of Crystallography (IUCr)
Date: 21-06-2023
DOI: 10.1107/S160057752300454X
Abstract: The ability to utilize a hybrid-photon-counting detector to its full potential can significantly influence data quality, data collection speed, as well as development of elaborate data acquisition schemes. This paper facilitates the optimal use of EIGER2 detectors by providing theory and practical advice on (i) the relation between detector design, technical specifications and operating modes, (ii) the use of corrections and calibrations, and (iii) new acquisition features: a double-gating mode, 8-bit readout mode for increasing temporal resolution, and lines region-of-interest readout mode for frame rates up to 98 kHz. Ex les of the implementation and application of EIGER2 at several synchrotron sources (ESRF, PETRA III/DESY, ELETTRA, AS/ANSTO) are presented: high accuracy of high-throughput data in serial crystallography using hard X-rays suppressing higher harmonics of undulator radiation, improving peak shapes, increasing data collection speed in powder X-ray diffraction faster ptychography scans and cleaner and faster pump-and-probe experiments.
Phase-diverse Fresnel coherent diffractive imaging of malaria parasite-infected red blood cells in the water window
Publisher: The Optical Society
Date: 18-12-2013
DOI: 10.1364/OE.21.032151
Low-Noise Diamond-Based D.C. Nano-SQUIDs
Publisher: American Chemical Society (ACS)
Date: 20-04-2022
Broadband X-ray ptychography
Publisher: AIP Publishing LLC
Date: 2016
DOI: 10.1063/1.4937542
Hole-lifetime width: A comparison between theory and experiment
Publisher: Elsevier BV
Date: 2003
The influence of noise on image quality in phase-diverse coherent diffraction imaging
Publisher: IOP Publishing
Date: 21-12-2015
Mapping biological composition through quantitative phase and absorption X-ray ptychography
Publisher: Springer Science and Business Media LLC
Date: 28-10-2014
DOI: 10.1038/SREP06796
Nanoscale Fresnel Coherent diffraction imaging tomography using ptychography
Publisher: The Optical Society
Date: 12-10-2012
DOI: 10.1364/OE.20.024678
Partial coherence: A route to performing faster coherent diffraction imaging
Publisher: IOP Publishing
Date: 25-10-2013
Soft X-ray ptychography as a tool for in operando morphochemical studies of electrodeposition processes with nanometric lateral resolution
Publisher: Elsevier BV
Date: 10-2017
Auger-photoelectron coincidence spectroscopy of SiO2
Publisher: Elsevier BV
Date: 10-2007
Corrosion mechanism of SS316L exposed to NaCl/Na2CO3 molten salt in air and argon environments
Publisher: Elsevier BV
Date: 02-2022
Modal approach for partially coherent diffractive imaging with simultaneous sample and coherence recovery
Publisher: The Optical Society
Date: 02-05-2017
DOI: 10.1364/OE.25.010757
The M5 photoelectron line of Ag metal measured in coincidence with the M5 -N45 N45 Auger-electron spectral line
Publisher: Elsevier BV
Date: 04-2005
Correlated positron–electron emission from surfaces
Publisher: IOP Publishing
Date: 12-09-2008
Polycrystalline materials analysis using the Maia pixelated energy-dispersive X-ray area detector
Publisher: Cambridge University Press (CUP)
Date: 26-09-2017
DOI: 10.1017/S0885715617000768
Abstract: Elemental, chemical, and structural analysis of polycrystalline materials at the micron scale is frequently carried out using microfocused synchrotron X-ray beams, sometimes on multiple instruments. The Maia pixelated energy-dispersive X-ray area detector enables the simultaneous collection of X-ray fluorescence (XRF) and diffraction because of the relatively large solid angle and number of pixels when compared with other systems. The large solid angle also permits extraction of surface topography because of changes in self-absorption. This work demonstrates the capability of the Maia detector for simultaneous measurement of XRF and diffraction for mapping the short- and long-range order across the grain structure in a Ni polycrystalline foil.
Whole-cell phase contrast imaging at the nanoscale using Fresnel Coherent Diffractive Imaging Tomography
Publisher: Springer Science and Business Media LLC
Date: 26-07-2013
DOI: 10.1038/SREP02288
Fresnel coherent diffractive imaging tomography of whole cells in capillaries
Publisher: IOP Publishing
Date: 05-09-2014
Multi-modal Nanoscale Imaging of Materials and Biology
Publisher: Oxford University Press (OUP)
Date: 08-2018
Spectroscopic ellipsometry of TaNx and VN films
Publisher: Elsevier BV
Date: 05-2004
X-ray Photoelectron Emission Microscopy and Time-of-Flight Secondary Ion Mass Spectrometry Analysis of Ultrathin Fluoropolymer Coatings for Stent Applications
Publisher: American Chemical Society (ACS)
Date: 11-07-2008
DOI: 10.1021/LA8002788
Abstract: Fluoropolymer plasma coatings have been investigated for application as stent coatings due to their chemical stability, conformability, and hydrophobic properties. The challenge resides in the capacity for these coatings to remain adherent, stable, and cohesive after the in vivo stent expansion, which can generate local plastic deformation of up to 25%. Plasma-coated s les have been prepared by a multistep process on 316L stainless steel substrates, and some coated s les were plastically deformed to mimic a stent expansion. Analyses were then performed by X-ray photoelectron spectroscopy (XPS), X-ray photoelectron emission microscopy (X-PEEM), and time-of-flight secondary ion mass spectrometry (TOF-SIMS) to determine the chemical and physical effects of such a deformation on both the coating and the interfacial region. While XPS analyses always showed a continuous coating with no significant effect of the deformation, TOF-SIMS and near-edge X-ray absorption fine structure (derived from X-PEEM) data indicated the presence of a certain density of porosity and pinholes in all coatings as well as sparse fissures and molecular fragmentation in the deformed ones. The smallness of the area fraction affected by the defects and the subtlety of the chemical changes could only be evidenced through the higher chemical sensitivity of these latter techniques.
A phenomenological model of the X-ray pulse statistics of a high-repetition-rate X-ray free-electron laser.
Publisher: International Union of Crystallography (IUCr)
Date: 03-10-2023
Tof-sims investigation of epoxy resin curing reaction at different resin to hardener ratios
Publisher: Wiley
Date: 26-08-2008
DOI: 10.1002/APP.28813
Propagation-based x-ray phase contrast imaging using an iterative phase diversity technique
Publisher: IOP Publishing
Date: 15-02-2018
Auger photoelectron coincidence spectroscopy: simplifying complexity
Publisher: Wiley
Date: 29-03-2006
DOI: 10.1002/SIA.2332
Shot-to-shot two-dimensional photon intensity diagnostics within megahertz pulse-trains at the European XFEL
Publisher: International Union of Crystallography (IUCr)
Date: 08-06-2022
DOI: 10.1107/S1600577522005720
Abstract: Characterizing the properties of X-ray free-electron laser (XFEL) sources is a critical step for optimization of performance and experiment planning. The recent availability of MHz XFELs has opened up a range of new opportunities for novel experiments but also highlighted the need for systematic measurements of the source properties. Here, MHz-enabled beam imaging diagnostics developed for the SPB/SFX instrument at the European XFEL are exploited to measure the shot-to-shot intensity statistics of X-ray pulses. The ability to record pulse-integrated two-dimensional transverse intensity measurements at multiple planes along an XFEL beamline at MHz rates yields an improved understanding of the shot-to-shot photon beam intensity variations. These variations can play a critical role, for ex le, in determining the outcome of single-particle imaging experiments and other experiments that are sensitive to the transverse profile of the incident beam. It is observed that shot-to-shot variations in the statistical properties of a recorded ensemble of radiant intensity distributions are sensitive to changes in electron beam current density. These changes typically occur during pulse-distribution to the instrument and are currently not accounted for by the existing suite of imaging diagnostics. Modulations of the electron beam orbit in the accelerator are observed to induce a time-dependence in the statistics of in idual pulses – this is demonstrated by applying radio-frequency trajectory tilts to electron bunch-trains delivered to the instrument. We discuss how these modifications of the beam trajectory might be used to modify the statistical properties of the source and potential future applications.
High-speed free-run ptychography at the Australian Synchrotron
Publisher: International Union of Crystallography (IUCr)
Date: 17-01-2022
DOI: 10.1107/S1600577521012856
Abstract: Over the last decade ptychography has progressed rapidly from a specialist ultramicroscopy technique into a mature method accessible to non-expert users. However, to improve scientific value ptychography data must reconstruct reliably, with high image quality and at no cost to other correlative methods. Presented here is the implementation of high-speed ptychography used at the Australian Synchrotron on the XFM beamline, which includes a free-run data collection mode where dead time is eliminated and the scan time is optimized. It is shown that free-run data collection is viable for fast and high-quality ptychography by demonstrating extremely high data rate acquisition covering areas up to 352 000 µm 2 at up to 140 µm 2 s −1 , with 13× spatial resolution enhancement compared with the beam size. With these improvements, ptychography at velocities up to 250 µm s −1 is approaching speeds compatible with fast-scanning X-ray fluorescence microscopy. The combination of these methods provides morphological context for elemental and chemical information, enabling unique scientific outcomes.
Ptychographic fresnel coherent diffraction tomography at the nanoscale
Publisher: Walter de Gruyter GmbH
Date: 14-07-2014
DOI: 10.3139/146.111065
Abstract: The spatial resolution of diffractive imaging techniques depends upon the numerical aperture of the detected scatter rather than any image forming optics. Fresnel coherent diffractive imaging has been developed over the past decade as a means for examining regions of interest within continuous s les and for overcoming many of the stagnation issues traditionally associated with coherent diffractive imaging. Ptychography meanwhile has been developed independently as a method of reconstructing the transmission function of extended objects from diffraction data recorded using a sequence of multiple overlapping probes on the s le. The relatively recent combination of these two methods has been found to provide substantial benefits over either of the two techniques when applied separately. The experimental requirements and basic principles of ptychographic Fresnel diffraction tomography are reviewed in this paper.
Simultaneous X-ray diffraction, crystallography and fluorescence mapping using the Maia detector
Publisher: Elsevier BV
Date: 02-2018
Time-of-flight secondary ion mass spectrometry investigation of epoxy resin curing behavior in real Time
Publisher: Wiley
Date: 29-04-2009
DOI: 10.1002/APP.30136
Simultaneous nanostructure and chemical imaging of intact whole nematodes
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8CC09664C
Abstract: Accurately locating biologically relevant elements at high resolution: simultaneous ptychography and fluorescence imaging of large specimens comes of age.
Characterization of an indirect X-ray imaging detector by simulation and experiment
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.ULTRAMIC.2014.08.010
Abstract: We describe a comprehensive model of a commercial indirect X-ray imaging detector that accurately predicts the detector point spread function and its dependence on X-ray energy. The model was validated by measurements using monochromatic synchrotron radiation and extended to polychromatic X-ray sources. Our approach can be used to predict the performance of an imaging detector and can be used to optimize imaging experiments with broad-band X-ray sources.
A soft X-ray beamline for quantitative nanotomography using ptychography
Publisher: SPIE
Date: 26-09-2013
DOI: 10.1117/12.2027211
Two-particle emission from LiF(1 0 0) upon photon, electron and positron excitation
Publisher: IOP Publishing
Date: 11-2009
Application of a complex constraint for biological samples in coherent diffractive imaging
Publisher: The Optical Society
Date: 03-12-2013
DOI: 10.1364/OE.21.030275
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Linkage Infrastructure, Equipment And Facilities - Grant ID: LE130100192
Start Date: 10-2013
End Date: 12-2018
Amount: $150,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE160100124
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End Date: 12-2016
Amount: $300,000.00
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View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE120100028
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View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE200100174
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End Date: 12-2022
Amount: $425,000.00
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