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ANSTO User Meeting 2019

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Muse

Muse

18 Wally Way
Hannah Wells (Massey University)
Description

 

In 2019, ANSTO will host a User Meeting at the MUSE
- Macquarie University NSW campus to showcase the
achievements of scientists who have accessed ANSTO’s
landmark infrastructure and capabilities in the last year.


The event will coincide with the combined annual meetings
of the Australian Neutron Beam Users Group (ANBUG) and
the Australian Synchrotron Users Advisory Committee (UAC).


Several hundred participants are expected to attend the
event, in which instrument users have the opportunity to
showcase their recent research accomplishments.


It is also an opportunity for prospective users to hear about
the unique capabilities of ANSTO’s scientific infrastructure,
which comprises a suite of neutron beam instruments in
Sydney and synchrotron beamline in Melbourne. ANSTO
also offers a range of other capabilities for scientific
investigations including radiation measurements, use of
natural and radioactive isotopes, radiochemistry, materials
characterisation, accelerator mass spectrometry and ion
beam analysis among others.
The

AUM2019 - Draft Program.pdf
Organising Committee
  • Monday, 2 December
    • 08:00 → 09:00
      Registration
    • 09:00 → 09:15
      Session 0: Opening and Opening Address
      Conveners: Hannah Wells (Massey University), Tracy Rushmer (Macquarie University)
    • 09:15 → 10:00
      Organisational Update
    • 10:00 → 10:30
      Plenary: Plenary 1
      • 10:00
        Impact of Pancratistatin on model mitochondrial membranes 30m

        Pancratistatin (PST) is a natural compound found in the spider lily, native to the Amaryllidaceae plant family. PST has been shown to selectively eliminate human cancer cells with minimal/no toxic consequences on normal cells. Unfortunately, PST lacks appearances in clinical trials due to its low natural abundance. Recently, PST analogues have been synthesized and have demonstrated anticancer activity on various types of cancer cells. Studies have strongly suggested that PST interacts with the lipids in the mitochondria membrane of cancer cells, causing cell death. However, a precise mechanism of how PST impacts the mitochondria, ultimately eliminating cancer cells, remains unknown. We combine Neutron Spin-Echo (NSE) and small angle scattering techniques to determine PST’s influence on the structure and membrane bending dynamics of mitochondrial model membranes. The goal of this research is to understand how PST interacts with the mitochondria by uncovering structural and dynamic information of how PST influences the mitochondrial membranes of cancer cells

        Speaker: Dr Drew Marquardt (Drew Marquardt)
    • 10:30 → 11:00
      Morning Tea 30m
    • 11:00 → 12:50
      Session 1: Advanced Materials - T1
      • 11:00
        Architectural and Structural Designs of Mo-CeO2-x Heterostructures To Achieve High Theoretical Capacitance 20m

        Tailoring the nanostructure of a supercapacitor with desired functionality necessitates both architectural and structural designs. Ultrathin two-dimensional architecture has emerged as one of the most promising candidates owing to the advantage of short diffusion pathways. Moreover, structural modifications through creation of exposed defects at the electrolyte intersection would maximise the charge storage performance. In this work, architecturally and structurally designed free-standing 2D CeO2-x, with ultrahigh surface area of 270 m2/g with volumetric oxygen vacancy was fabricated on nickel foam using chronoamperometric electrodeposition. The novel 2D CeO2-x were assessed for pseudocapacitive performance revealing an extremely high value of 582 F/g (scan rate 1 mV/s) that exceeds the theoretical capacitance of CeO2 (562 F/g). Further structural optimisation was conducted by implantation of molybdenum (Mo) at different fluences on the CeO2-x resulting in Mo-CeO2-x hybrid nanostructure. This unique nanostructure exhibited enhanced gravimetric capacitance of 746 F/g with high charge/discharge stability of 98% after 2500 cycles. In addition, ab-initio DFT and ex-situ XPS results revealed the role of oxygen vacancies in enhancing the capacitance of CeO2-x, thereby revealing a new mechanism route for dual-valence metal oxides.

        Speaker: Dr Pramod Koshy (School of Materials Science and Engineering UNSW)
      • 11:20
        In-situ X-ray powder diffraction for Li-ion batteries: The effects of Ni on inhibiting the separation of Cu during the lithiation and delithiation of Cu6Sn5 anodes 15m

        Lithium-ion batteries have found numerous applications in modern technologies, especially in portable devices, and increasingly in electric vehicles and renewable energy storage applications. Sn-based lithium-ion battery anodes have a higher theoretical storage capacity of 993 mAh g-1 vs. 372 mAh g-1 compared to commercial carbon-based anodes. Their better safety profile due to a lower risk of lithium dendrite formation is also desirable. However, Sn-based anodes suffer from inferior cycling performance due to the enormous stresses during the lithiation and delithiation process. Alloying Sn with Cu can reduce the reaction stresses in the anode, as Cu does not react with Li, and acts as a stress buffer. Cu6Sn5 is therefore a promising candidate material to replace carbon-based anodes. However, the separation of Cu during the second stage of the lithiation reaction limits the kinetics and degrades the cyclability of the anodes. This study proposes an effective method of inhibiting the separation of Cu via the addition of Ni. Ni occupies the Cu positions in the Cu6Sn5 crystal structures to form (Cu, Ni)6Sn5, and therefore alters the crystal structure of the anode, leading to the formation of superstructures that were identified using the Australian Synchrotron PD beamline. As a result, Ni partially blocks the diffusion pathways of Li and therefore inhibits the Cu separation reaction, while the superstructure provides additional Li storage sites to increase the capacity of the anodes.

        Speaker: Xin Fu Tan (University of Queensland)
      • 11:35
        The Electronic and Vibrational Structure Of Lanthanide Zirconates 15m

        The lanthanide zirconates are of interest for their use in inert matrix fuels and as nuclear wasteform containment material. For use in these applications, the material's structure must be as resistant as possible to radiation damage, and, therefore, at a basic level, present an electronic and vibrational structure with thermodynamic and mechanical properties that are favourable to long term structural stability under harsh radiation environments. The rare earth zirconates are interesting model systems to explore such problems. This study finds that in these materials the f-electrons play a localized-valence decisive role in determining their thermo-mechanical properties making them an intriguing model for the interplay between the localised and delocalised valence nature of such oxide materials, the full understanding of which may also lead to novel material development. The f-electronic structure has, however, historically proved rather difficult to model. The full series of lanthanide zirconates was synthesised using solid state techniques and a variety of neutron and synchrotron experiments performed to study the electronic and vibrational structure of this series. In conjunction with a density functional theory (DFT) model, the electronic and vibrational structure is determined and the role of the 4 f electrons to the stability of these interesting materials studied. Unlike the lanthanide titanate series, the interplay between electronic and vibrational character plays the decisive role in determining the fate of the materials stability.

        Speaker: Anton Stampfl (Australian Nuclear Science and Technology Organisation)
      • 11:50
        Radiation Damage Characterisation of Organic Semiconductors 15m

        The radiation damage of a fullerene-composite bulk heterojunction organic photodetector was characterised for samples that have been exposed to ionising radiation in increments of 10kGy up to a total accumulated irradiation dose of 40kGy. Irradiation was achieved by a cobalt-60 gamma source (dose rate = 1.2kGy/h) at the Australian Nuclear Science and Technology Organisation. Between each irradiation the Charge Collection Efficiency of the photodetector was measured using an LED (520nm) in a dark environment. Normalised to the Charge Collection Efficiency prior to irradiation, the response after exposure to 40kGy decreased by 40%. The mobility of a photodetector exposed to 40kGy was compared to an un-irradiated sample via the Time-of-Flight method. A picosecond pulsed laser incident upon the sample was used to inject photo-generated charge carriers within the bulk. The measurement of the carrier transient was used to obtain the carrier drift time of the organic photodetector. The drift time at 20V bias was determined to be (2.727 ± 0.002)μs and (1.525 ± 0.002)μs for the photodetectors exposed to 0 and 40kGy, respectively. The decrease in drift time due to the accumulated radiation damage is associated with a lower charge collection efficiency. Calculation of the drift mobility shows an increase in carrier mobility as a function of radiation damage. This result combined with the drift time measurements suggests that the effective thickness of the device varies as a function of total ionising dose. This effect can be explained by hypothesising a high recombination rate of the irradiated devices and their capability to collect charge carriers only from regions close to the electrodes. A shorter lifetime of the charge carriers in the highly irradiated device is suggested to explain the faster rise and fall time of the transient time. The Charge Collection Efficiency and Time-of-Flight method have provided valuable insight into the effects of radiation damage upon the charge transport characteristics of organic compounds.

        Speaker: Jessie Posar
      • 12:05
        Investigation of the stability range of the skyrmion phase in doped Cu$_2$OSeO$_3$ 15m

        A skyrmion is a topological stable particle-like object comparable to spin vortex at the nanometre scale. It consists of an about 50 nm large spin rotation which order in a 2 dimensional, typically hexagonal superstructure perpendicular to an applied external magnetic field. Its dynamics has links to flux line vortices as in high temperature superconductors. Cu$_2$OSeO$_3$ is a unique case of a multiferroic materials where the skyrmion dynamics could be controlled through the application of an external electric field. The direct control of the skyrmion dynamics through a non-dissipative method would offer technological benefits and unique possibilities for testing fundamental theories also related to the Higgs Boson whose theoretical description has similarities to skyrmions. Important for technological applications would be a stability range of the skyrmion phase up to room temperature. While room temperature skyrmion materials exist, Cu$_2$OSeO$_3$ orders magnetically below 60 K. Our combined small angle neutron scattering, SQUID magnetization measurements, and electron microscopy investigations did provide direct evidence that the stability range of the skyrmion phase can be extended in Te-doped Cu$_2$OSeO$_3$. This did provide valuable information on the formation mechanism of the skyrmions and their scaling behavior.

        Speaker: Clemens Ulrich (The University of New South Wales)
      • 12:20
        Shedding light on the subtle differences in Li-S cell operation when using safer ionic liquid based electrolytes 15m

        Lithium-sulfur (Li-S) batteries have the potential to replace lithium-ion batteries due to their high theoretical energy density and potentially reduced environmental impact. However, they still face many challenges in terms of operation and safety to become more attractive in a commercial-standpoint. Of particular interest is the use of safer, less-flammable electrolyte compositions involving ionic-liquids (ILs). Despite an increase in capacity retention as well as enhanced safety when using IL-based electrolytes, there is still a lack of understanding on the inherent electrochemistry involved when using these electrolyte compositions in Li-S cells, in particular whether there is a difference in SEI composition relative to using conventional organic solvent based electrolytes.

        Herein synchrotron-based techniques namely in-situ X-ray powder diffraction and ex situ X-ray Absorption Near Edge Structure (XANES) spectroscopy, both performed at the Australian Synchrotron, are used to clarify the subtle differences between using IL-based and more conventionally used organic solvent-based electrolytes in Li-S cells. Our in-situ X-ray powder diffraction studies revealed the formation of the generally less-stable β-S8 phase upon multiple charge-discharge cycles when using the C4mpyr-TFSI based electrolyte. The data also showed a more distinct formation of solid Li2S when using the C4mpyr-TFSI based electrolyte versus using DOL/DME-based electrolyte, suggesting that C4mpyr-TFSI based electrolytes facilitate for complete reduction of S8 to Li2S. Whilst the use of LiTFSI and LiNO3 salts is generally known to stabilize the SEI in Li-S cells, XANES spectroscopy of electrochemically treated Li-S cells revealed subtle differences in the SEI composition when using C4mpyr-TFSI-based vs DOL/DME-based electrolytes. A larger buildup of TFSI-anion was observed on the Li-anode when using the C4mpyr-TFSI electrolyte relative to the DOL/DME composition, which could account for the cell’s improved performance when using the C4mpyr-TFSI-based electrolyte.

        Speaker: Lisa Djuandhi (UNSW)
    • 11:00 → 12:50
      Session 2: Technique Development - T11
      • 11:00
        X-ray ghost imaging: Line scans, radiography and tomography 20m

        Ghost imaging is a new field of optics. Emerging from the field of quantum optics and initially believed to be underpinned by quantum-mechanical “spooky action at a distance”, the field has rapidly achieved prominence in studies using classical visible light [1].

        In ghost imaging, photons from a source pass through a speckle-making mask, leading to a spatially random pattern “A” being measured over the surface of a position-sensitive detector. A beam-splitter then removes a very small fraction of the photons, which pass through an object and are then recorded by a single-pixel “bucket” detector that merely records the total number “B” of photons falling upon it. This process is repeated for a number of different mask positions. While no photon that ever passes through the object is ever registered by a position-sensitive detector, and no photons measured by the position sensitive detector ever pass through the object, the correlation between A and B can be used to reconstruct the object [1].

        Ghost imaging using x-rays was only very recently achieved, with the first proofs of concept for one-dimensional x-ray ghost imaging being published by Yu et al. [2] and Pelliccia et al. [3] in 2016. This was soon extended to x-ray ghost imaging of two-dimensional objects, by Zhang et al. [4] and Pelliccia et al. [5]. Finally, based on the theory and computer modelling of Kingston et al. [6], the first experimental realisation of ghost tomography (using potentially any form of radiation, not just x-rays) was reported by Kingston et al. [7] with x rays. The experimental setup uses the process as described above, but with the additional feature that the sample was rotated to a number of different angular orientations.

        We discuss the origins of ghost imaging, explain the key principles underpinning the method, review the current state of art in x-ray ghost imaging in 1D (line scans), 2D (radiography) and 3D (tomography), consider some key drivers such as the quest for ever-reduced dose, and speculate regarding future developments. We attempt to reduce the counter-intuitive nature of the method to a retrospectively obvious simplicity, and address the obvious question of: “Why would one want to perform tomographic imaging in this peculiar manner?”

        [1] O. Katz, Y. Bromberg & Y. Silberberg. Applied Physics Letters, 95, 131110, 2009.
        [2] H. Yu, R. Lu, S. Han, H. Xie, G. Du, T. Xiao & D. Zhu. Physical Review Letters, 117, 113901, 2016.
        [3] D. Pelliccia, A. Rack, M. Scheel, V. Cantelli & D.M. Paganin. Physical Review Letters, 117, 113902, 2016.
        [4] A.-X. Zhang, Y.-H. He, L.-A. Wu, L.-M. Chen & B.-B. Wang. Optica, 5, 374-377, 2018.
        [5] D. Pelliccia, M.P. Olbinado, A. Rack, A.M. Kingston, G.R. Myers & D.M. Paganin. IUCrJ, 5, 428-438, 2018.
        [6] A.M. Kingston, G.R. Myers, D. Pelliccia, I.D. Svalbe & D.M. Paganin. IEEE Transactions on Computational Imaging, 5, 136-149, 2019.
        [7] A.M. Kingston, D. Pelliccia, A. Rack, M.P. Olbinado, Y. Cheng, G.R. Myers & D.M. Paganin. Optica, 5, 1516-1520, 2018.

        Speaker: Prof. David Paganin (Monash University)
      • 11:20
        Small Angle Neutron Scattering Capability at the Australian Nuclear Science and Technology Organisation 15m

        Small angle scattering is a technique that provides information about the size and overall shape of structures on the nanoscale. Although not a ‘real space’ technique such as microscopy, small angle scattering presents certain advantages over microscopy such as the ability to study molecules and their self-assembly in solution. Samples can then readily be studied under a range of conditions such as temperature, pH, pressure, application of shear etc…
        Three world-class small angle neutron scattering (SANS) instruments are now located at the ANSTO Lucas Heights campus south of Sydney, covering space-scales from 1 nm to 10 microm [1-3]. A complementary bench top small angle X-ray instrument is also available [4]. All four instruments are accessible to the community via our user programme. We here outline the advantages and limitations of using SANS to study the nano to microstructure of materials, taking examples from recently published work.

        [1] K. Wood, J. P. Mata, C. J. Garvey, C. M. Wu, ... and E. P. Gilbert, QUOKKA, the pinhole small-angle neutron scattering instrument at the OPAL Research Reactor, Australia: design, performance, operation and scientific highlights, J Appl Crystallogr, 2018, 51, 294-314.
        [2] Rehm, C.; Campo, L. d.; Brûlé, A.; Darmann, F.; Bartsch, F.; Berry, A., Design and performance of the variable-wavelength Bonse–Hart ultra-small-angle neutron scattering diffractometer KOOKABURRA at ANSTO. J Appl Crystallogr, 2018, 51 (1), 1-8.
        [3] A. Sokolova, A. E. Whitten, L. de Campo, J. Christoforidis, A. Eltobaji, J. Barnes, F. Darmann and A. Berry, Performance and characteristics of the BILBY time-of-flight small-angle neutron scattering instrument, J Appl Crystallogr, 2019, 52, 1-12.
        [4] https://archive.ansto.gov.au/ResearchHub/OurInfrastructure/ACNS/Facilities/Instruments/SAXS/BrukerSAXS/

        Speaker: Kathleen Wood (Australian Nuclear Science and Technology Organisation)
      • 11:35
        Synchrotron Radiotherapy of Pet Cadavers at the Imaging and Medical Beamline in Anticipation of Live Veterinary Animal Trials 15m

        Introduction

        Hutch 3B at the Australian Synchrotron’s Imaging and Medical Beamline (IMBL) offers the unique opportunity to deliver Synchrotron Radiotherapy (SR) to pet animals and human patients with much larger field sizes than is possible in Hutch 2B. Hutch 3B, located 140m away from the Synchrotron X-ray source, allows for a minimally-divergent beam and clinically comparable field-sizes, while maintaining dose rates of 100’s Gy/s in water.

        Veterinary interest in performing radiotherapy on domestic pets has facilitated recent preliminary studies into the applicability of using the Large Animal Position System (LAPS) robot in Hutch 3B to delivery mock radiotherapy fields to animal cadavers. All stages of the treatment delivery were investigated including CT simulation, treatment planning, patient positioning, dose delivery, and dose verification.

        Method

        2 Dog cadavers and 1 lamb cadaver, each provided by an Australian Synchrotron on-site veterinarian, were CT scanned at the Monash Biomedical Imaging facility. Care was taken to ensure that the animals were scanned in the position they would be in during treatment. A carbon fibre CT imaging board with fiducial markers was used for coarse alignment. For 1 of the 2 dog cadaver trials, air-vacuum bags were used to position the cadaver with the assistance of a veterinarian and a trained clinical radiation therapist.

        The CT scans of the cadaver animals were imported into the Eclipse Treatment Planning System (TPS) were SR fields were planned for treatment. A Hybrid Monte Carlo dose algorithm was used to calculate the dose distributions through the patient CTs. Reference dosimetry plans were also produced in order to calculate Monitor Units (the exposure time required to deliver the prescribed dose).

        For treatment, the animal cadavers were re-positioned onto the LAPS, and an Australian Synchrotron in-house developed software (SMRT) was used to align the cadaver. Radiochromic film was used to verify the treatment delivery. Doses calculated in the Quality Assurance (QA) plans where verified using ionisation chamber measurements in liquid water and Solid Water phantoms.

        Results

        We irradiated the cadaver animals using the LAPS in Hutch 3B under image guidance, with successful patient alignment and treatment planning. Larger fields were delivered via a 'step-and-shoot' method and Radiochromic film was used to verify the delivery of the treatment field to the target.

        Ionisation chamber measurements in liquid water and Solid Water showed good agreement (within 5%) with the QA plans.

        Dynamic scanning of the animal cadaver is not currently feasible due to technical limitations of the LAPS, and so 'step-and-shoot' remains the only viable method for delivering clinically relevant treatment field sizes.

        Conclusion

        Synchrotron Radiotherapy for live animal trials is achievable with our current software implementations, including image guidance and treatment planning. Larger fields can be delivered adequately using step-and-shoot for Synchrotron Broadbeam Radiotherapy, with good dosimetric agreement.

        Microbeam Radiotherapy veterinary trials for client-owned pets will require the animal to be dynamically scanned through the beam. Future work will therefore focus on implementing a combination of software and hardware improvements to the LAPS in order to facilitate dynamic Synchrotron Radiotherapy in Hutch 3B.

        Speaker: Liam Day (Royal Melbourne Institute of Technology)
      • 11:50
        Australian Synchrotron MX beamlines - The Impact of Dectris Eiger Detectors 15m

        The Australian Synchrotron MX beamlines support a user community that includes both Structural Biology (PX) and Chemical Crystallography (CX). Addressing the needs of both communities leads to a number of compromises regarding the design and implementation of the beamline infrastructure; however it also leads to unique opportunities.
        Both MX Beamlines have recently had detector upgrades; MX2 received a Dectris Eiger 16M with the assistance of the Australian Cancer Research Foundation in Jan 2017 and MX1 commissioned a Dectris Eiger 2 9M in May 2019. These single photon counting detectors replace the previous CCD Area detectors, with the improvement in technology allowing an increase in frame rates from one second a frame to >0.01 seconds a frame.
        These new detectors have had significant impact on not only the throughput of the data collection but impacted the strategy taken to collect good data for the diverse PX and CX user communities. This changes the way the beamlines have been used, and presents some new unique opportunities.

        Speaker: Daniel Eriksson (Australian Synchrotron)
      • 12:05
        Microscopy capabilities at the Australian Synchrotron 15m

        Microscopy capabilities at the Australian Synchrotron include Infrared Microscopy (IRM) and X-ray fluorescence microscopy (XFM) [1].

        Infrared Microscopy or Fourier Transform Infrared (FTIR) spectroscopy can provide spatially resolved spectroscopic information on organic and inorganic compounds. High brilliance synchrotron IR enables high signal-to-noise ratios at spatial resolutions between 3–8 μm, making IRM ideally suited to the analysis of microscopic samples, single cells and complex biological systems. IRM can employ Attenuated Total Reflection (ATR) to enable analysis of more difficult samples, e.g. samples that cannot be microtomed or do not adequately reflect. ATR offers enhanced spatial resolution below the diffraction limit.

        XFM can provide elemental and chemical microanalysis across millimeter to nanometer length scales. XFM is ideally suited to quantitatively map trace elements within whole and sectioned plant, biological specimens and environmental samples. High elemental sensitivity coupled with deep penetration allows investigation of diverse samples in situ or under environmental conditions. Elemental maps can be acquired rapidly which enables higher-dimensional studies including fluorescence tomography [2], X-ray absorption near edge structure (XANES) imaging, and XANES tomography. The speed and efficiency of the technique ensures the lowest possible dose and can avoid radiation damage.

        Transmission FTIR spectroscopy was used to examine single live cells in aqueous media [3,4]. Bone disease was studied by examining bone quality after drug treatment using reflectance IRM [5,6]. Insights into lipid composition of brain neurons in brain tissue without the need for staining have been provided by macro ATR-FTIR [7].

        X-ray fluorescence XANES imaging investigated in vivo coordination environments of metals in biological specimens [8]. Copper coordination chemistry within Drosophila melanogaster was visualised with fluorescence XANES tomography [9]. XANES imaging can be applied to fresh and hydrated plants, e.g., selenium speciation imaging in wheat and rice roots and leaves [10].

        High-resolution coherent imaging at XFM brings together X-ray ptychography, spectroscopy and X-ray fluorescence to reveal morphology and speciation at nanometer resolution [11].

        Increasingly, researchers use the combined capabilities of IRM and XFM to provide powerful correlative analysis, e.g. to provide understanding of the chemical and elemental composition of latent fingermarks. [12].

        Future microscopy capabilities include the BRIGHT Nanoprobe beamline providing versatile X-ray microscopy with sub-70 nm spatial resolution.

        References

        [1] D. Paterson et al., AIP Conference Proceedings 1365 (2011) 219.
        [2] M. D. de Jonge et al., Optics Express 25 (2017) 23424.
        [3] M. J. Tobin et al., Vibrational Spectroscopy 53 (2010) 34.
        [4] K. Petrou et al., Frontiers in Marine Science 5 (2018) 110.
        [5] C. Vrahnas et al., Bone 93 (2016), 146.
        [6] C. Vrahnas et al., Calcified Tissue International 103 (2018) 625.
        [7] J. Vongsvivut et al., Analyst 144 (2019) 3226.
        [8] S. A. James et al., Scientific Reports 6 (2016) 20350.
        [9] S. A. James et al., Chemical Communications 52 (2016) 11834.
        [10] P. Wang et al., Journal of Experimental Botany 66 (2015) 4795.
        [11] M. W. M. Jones et al., Chemical Communications 55 (2019) 1052.
        [12] R. E. Boseley et al., Analytical Chemistry 9 (2019) 10622.

        Speaker: Dr David Paterson (Australian Synchrotron)
      • 12:20
        What Sample Environment Can Do For You 15m

        Sample environment at ACNS comprises a varied suite of instrumentation and equipment. In the last 12 months this has expanded with two new cryostats and a new helium dilution refrigerator being commissioned. We will talk about our capabilities, how to get the best out of our equipment and some recent unique and interesting sample environment set ups. These include a sample changer on our 5T magnet for use on the SANS instruments, line of sight cryostat sample probes to allow illumination and optical spectroscopy in-situ, combined electric and magnetic field studies of skrymions phases using SANS, and carbon fibre sample probes for fast cooling and quicker changes.
        There have been considerable changes the sample environment team at ACNS in the last two years. We have not only had significant changes in our team, we have also weathered a period of low resources in the first half of 2019. At this meeting we have a refreshed team and a positive future ahead of us supporting experiments and providing innovative sample environments
        Most importantly we want to hear from you during this presentation. We want to know what you want to achieve in your experiments; what is important for your samples and what combinations of sample conditions you want to try out during your neutron beam instruments. We want you to help us provide what you need in the coming years.

        Speakers: Norman Booth (ANSTO), Rachel White (ANSTO)
      • 12:35
        Iterative energy self-calibration of Fe XANES spectra 15m

        Determining the oxidation state of Fe through parameterisation of XANES spectral features is highly dependent on accurate and repeatable energy calibration between spectra. Small errors in energy calibration can lead to vastly different interpretations. While a simultaneous measurement of a reference foil is often undertaken on X-ray spectroscopy beamlines, other beamlines measure XANES spectra without a reference foil and therefore lack a method for correcting energy drift. Here we propose a method that combines two measures of Fe oxidation state taken from different parts of the spectrum to iteratively correct for an unknown energy offset between spectra. We show that the method is applicable even when the two spectra have been collected at different times and different beamlines, potentially eliminating the need to collect standard reference spectra during every beamtime.

        Speaker: Michael Jones (QUT)
    • 11:00 → 12:50
      Session 3: Chemistry and crystallography - T3
      • 11:00
        Microsecond-resolved look at the very early stages of quantum dot formation 20m

        To access the very early stages of nucleation and growth of nanoparticles in liquid media, we have developed a novel setup, where the reactants pushed by high power syringe pumps through a Y-shaped micromixer are immediately liberated as a free jet. With synchrotron X-ray scattering, this provides access to chemical reaction times as short as 10 µs. Diffraction data with CdS as a prototype example for quantum dot formation show a three-step pathway. Between 10 and 2500 µs, the CdS quantum dot formation starts with a rapid formation of primary clusters driven by the fast diffusion of cadmium and sulphur ions. Further particle growth is by cluster attachment. At this early stage, the particles are not yet crystalline. This reaction pathway is supported by ab initio theoretical calculations.

        Speaker: Prof. Andreas Magerl (University Erlangen-Nürnberg)
      • 11:20
        Magnetic order induced symmetry-breaking in the coupled honeycomb system Fe4(Nb,Ta)2O9 15m

        Magnetoelectric (ME) multiferroics are compounds which exhibit simultaneous magnetic ordering (MO) and electric polarization (EP) which are coupled. This coupling is utilized in applications such as MRAMs, sensors and capacitors. The ME effect is significant, if the emerging EP is of spin origin and the coupling is strong. However the emergence of EP and the coupling mechanism between these two orders are not completely understood and subject to extensive ongoing research. Three types of materials fulfill this requirement: (i) Type II multiferroics such as orthorhombic RMnO3 (R=rare earth), where spontaneous EP is induced by the MO, (ii) Polar magnets such as M2Mo3O8 (M=Fe and Mn), which also exhibit MO induced EP, but has a polar paramagnetic phase and (iii) Magnetoelectric materials such as Cr2O3, where EP is induced by an external magnetic field below MO [1-6]. M4A2O9 (M=Fe, Co, Mn and A=Nb,Ta) are a family of materials where depending on M, either (i) or (iii) emerge below MO. The unit cell contains two crystallographically distinct magnetic sites M, which form edge-shared coplanar and corner-shared buckled honeycombs which are connected along c. The interaction between the honeycombs enables a competition between the interlayer and the intralayer exchange interactions and anisotropies which results in ground states with various spin orderings [7-8]. Recently Fe4Ta2O9, in contrast to the magnetoelectric Co and Mn counterparts, was reported to exhibit symmetry-breaking and EP below MO from dielectric property measurements [9-10]. Elucidation of the emergence of EP in Fe4Ta2O9 necessitates a comprehension of its crystal, magnetic and electronic structure. In this work, we combined neutron powder diffraction, inelastic neutron scattering, bulk property measurements and theoretical methods to determine the crystal/magnetic structures, magnetic excitations and electronic structure of Fe4Ta2O9 and compared it with the related compound Fe4Nb2O9. Fe4Ta2O9 exhibits the unique feature of the emergence of both the symmetry-breaking multiferroic and magnetoelectric phases below MO, whereas Fe4Nb2O9 only exhibits magnetoelectric phases below MO. This enables Fe4(Nb,Ta)2O9 to be an ideal system to investigate the transition between the multiferroic and magnetoelectric phases. We elucidate these unique phenomena utilizing symmetry arguments in terms of spin and orbital degrees of freedom. 

          References:

        [1] I. E. Dzyaloshinskii, JETP 10, 628 (1959).
        [2] D. N. Astrov, JETP 11, 708 (1960).
        [3] S.-W. Cheong et al., Nat. Mater. 6, 13 (2007).
        [4] M. Kenzelmann et al., PRL 95, 087206 (2005).
        [5] T. Kurumaji et al., PRB 95, 045142 (2017).
        [6] T. Kurumaji et al., PRX 5, 031034 (2015).
        [7] N.Narayanan et al., PRB 98, 134438 (2018).
        [8] N. D. Khanh et al., PRB 93, 075117 (2016).
        [9]A. Maignan et al., PRM 2, 091401(R) (2018).
        [10] S. N. Panja et al., PRB 98, 024410 (2018).

        Speaker: Narendirakumar Narayanan (Postdoc)
      • 11:35
        Structural and electronic modification of KLaTiO4 hydrogen evolution catalyst 15m

        KLaTiO4 is a n=1 Ruddlesden-Popper type layered perovskite. KLaTiO4 can be used as a Hydrogen Evolution Catalyst (HEC), producing 9.540 μmol of H2 gas per hour from 20 mg of catalyst, when using methanol as sacrificial electron donor and platinum co-catalyst. The main disadvantage of KLaTiO4 is its high bandgap of 4.09 eV, above the visible light region, and therefore a poor choice for a HEC that attempts to use solar energy. To reduce the bandgap of sample to 3.10 eV (400 nm) both cationic and anionic doping of the sample is attempted. The crystal structures, and sample purity, was determined using X-ray powder diffraction. The structures have been refined by the Rietveld method using synchrotron and lab X-ray diffraction data. Hydrogen evolution was tested by illuminating a suspension of powder sample in water. Evolved gases were identified and quantified using gas chromatography.
        Cationic doping of KLaTiO4 was done by replacing lanthanum with praseodymium and ytterbium, yielding two solid solution series: KLaxPr1-xTiO4 and KLaxYb1-xTiO4 (x = 0.005, 0.01 and 0.03). While none of the samples from KLaxPr1-xTiO4¬ series produced hydrogen, all KLaxYb1-xTiO4 were able to produce H2 when illuminated by a Hg lamp with 305 nm filter. In comparison to KLaTiO4, ytterbium doped samples have a reduced catalytic activity compared to the undoped sample, as well as decrease in activity between 20 – 40 minutes, before increasing in rate of production again after 40 – minute mark.
        Anionic doping of KLaTiO4 was attempted by nitrogenation, by mixing KLaTiO4 urea and under N2 flow. PXRD pattern of initial samples shows loss in crystallinity of KLaTiO4 after the annealing process. Further attempts are underway, using PXRD to probe degree of sample degradation, in what is the optimal annealing condition that will achieve nitrogen doping without sacrificing complete loss in crystallinity.

        Speaker: Junwei Li (the University of Sydney, school of Chemistry)
      • 11:50
        Tailoring liquid crystal phase transitions by addition of silica nanoparticles 15m

        Liquid crystals (LCs) are materials with properties typically associated with both solids and melts. These systems possess both the structural order of crystals and the flow properties of liquids. One family of LC is the lyotropic LCs, which are formed by mixing otherwise immiscible solvents, usually with some molecularly anisotropic substance, such as a surfactant. Such systems can form a wide variety of shapes, including hexagonal lattices of cylindrical micelles or repeating sheet-like lamellar structures, and each possesses unique properties. Transitions between these phases can be controlled by various parameters, such as altering the concentration of any substituents, by changing the temperature, or by applying a shear strain.

        This study was conducted to determine the effect that adding silica nanoparticles (NPs) can have on the phase transition between different lyotropic LC phases. This work has implications for the application of LC systems as protein crystallisation media, as cellular models, and templates for synthesis. Structures were analysed using polarising light microscopy (PLM), and small-angle x-ray and neutron scattering (SAXS/SANS), with both rheological (rheoSANS) and thermal control.

        The results revealed that silica NPs can modulate LC mesophases by altering the thermal and rheological conditions required for phase transition. In one instance, they specifically prevent the formation of a hexagonal LC phase, while in other circumstances they can promote hexagonal phase formation after shear is stopped. This suggests that caution is required when designing LCs to be used as solvents, as any doped particles may affect the resulting phase behaviour. It also suggests the potential application of silica NPs as cryoprotectants, as well as the ability of NPs to customise the shear-response of different LC systems.

        Speaker: Joshua Marlow (Monash University)
      • 12:05
        Exotic Physics in Neutron Laue Diffraction 15m

        Laue diffraction at steady-state neutron sources has been reborn thanks largely to the success of X-ray Laue diffraction for protein crystallography at synchrotrons and to the development of efficient large-area neutron-sensitive image-plate detectors. The Laue technique with thermal neutrons is especially successful for crystallography on single crystals with volume typically 0.1 mm3 [1], and is opening neutron diffraction to fields of structural chemistry previously deemed impossible [2].

        The high-resolution volumetric view of reciprocal space is particularly advantageous in the detection of phase changes, incommensurability, and twinning, but does come at a price though: all scattering from the sample, inelastic as well as elastic, contributes to the observed Laue patterns. This can however reveal valuable physical information about the sample beyond the crystal structure, but careful analysis is required to extract the details in the two-dimensional projection intrinsic to Laue patterns.

        Examples of exotic physics in neutron Laue diffraction experiments on KOALA on the OPAL reactor, and presented here, include:
        • Observation of phonon scattering and determination of sound velocities
        • Separation of Bragg and thermal-diffuse scattering in perfect crystals
        • Observation of magnon scattering
        • Double diffraction and multiple scattering in experiments with diamond-anvil cells [3]
        • New phases in an aperiodic composite [4]

        References
        [1] G.J. McIntyre et al., Physica B 385-386 (2006) 1055-1058
        [2] A.J. Edwards, Aust. J. Chem. 64 (2011) 869-872
        [3] J. Binns et al., IUCrJ 3 (2018) 168-179
        [4] S. Zerdane et al., Acta Cryst. B 71 (2015) 293-299

        Speaker: Garry McIntyre (Australian Nuclear Science and Technology Organisation)
      • 12:20
        Structure determination of a zinc hydroxide chloride from powder diffraction 15m

        Zinc-air battery with near-neutral aqueous chloride electrolytes has received increasing attentions in high power applications recently. Unwanted precipitation of zinc hydroxide chloride products reduces the battery capacity and lifetime. One of these precipitation phases has unknown crystal structure. The diffraction pattern of a synthesised phase was collected on the Australia Synchrotron Powder Diffraction beamline, and its crystal structure was determined using simulated annealing method with the assistance of rigid body in DIFFRAC.TOPAS v6 software. The refined structure in P21/c space group shows similar layered construction to that in simonkolleite but more water molecule in the interlayer and larger layer spacing. The on-going work of crystal structure determination of this phase will support the study of precipitation mechanism in Zinc-Air batteries.

        Speaker: Tony WANG (Queensland University of Technology)
      • 12:35
        Phase and structural evolution of positive electrodes in lithium- and sodium-ion batteries 15m

        Lithium-ion batteries have revolutionized our lives and they, in conjunction with alternative battery chemistries such as sodium-ion batteries, are going to shape our lives in the near-future. Electrodes account for a significant proportion of battery function, where atomic-scale perturbations or changes in the crystal structure during an electrochemical process permit the reversible insertion/extraction of charge carriers. Therefore, determining the interplay between crystallography and electrochemistry is essential to understand and rationalize in order to deliver better materials and batteries.
        A large fraction of our work investigates the structure-electrochemistry relationship in-situ or operando using both neutron and synchrotron X-ray diffraction. In other words, exploring electrode structure evolution while a battery is operating. This presentation will showcase operando and in situ neutron powder diffraction studies on commercial lithium-ion batteries and operando and in situ X-ray powder diffraction studies on ambient temperature rechargeable sodium-ion batteries. With the information from these experiments one can directly relate electrochemical properties such as capacity, battery lifetime, applied rates and differences in charge/discharge to the content and distribution of sodium in the electrode crystal structures or the lattice parameter evolution.

        Speaker: Neeraj Sharma (UNSW)
    • 12:50 → 14:00
      Lunch 1h 10m
    • 14:00 → 15:00
      Session 4: Engineering, industry and innovation - T2
      • 14:00
        Materials development for Aerospace applications 20m

        This talk will focus on a synchrotron experimental programme developed for aerospace materials design and testing. The unique properties of the beamlines available at the Australian synchrotron facility have been applied in various modalities. A brief overview of current and future work is presented based on case studies developed on two beamlines,
        1. A dedicated synchrotron Small Angle Scattering (SAXS), Wide Angle Scattering (WAXS) fibre testing capability (Serial fibre X-ray scattering). The experimental design has been optimised for measurement of weakly scattering monofilament fibres with short acquisition times. Based on a scanning fibre-by-fibre measurement protocol, the structural parameters, density and relative distribution along the length of a fibre can be mapped for the first time. This technique is used to identify the “weakest link” microstructures and serves as an optimisation tool for fibre processing.

        1. The Imaging and Medical beamline for polychromatic/monochromatic diffraction measurements. High energy diffraction measurements are used to assess the build microstructure of 3D printed (Laser Engineered Net Shaping (LENS) deposition) Ti5553 metals. Application of spatially resolving measurements has been used to study the bi-modal grain size distribution introduced by the AM build process.
        Speaker: Dr Peter Lynch (Deakin University)
      • 14:20
        Study of the microstructure of carbon fiber monofilaments at the Australian Synchrotron SAXS/WAXS beamline 15m

        A new SAXS-WAXS methodology has been developed at the Australian Synchrotron for the structural analysis of carbon fibres. The new technique –referred to as serial SAXS-WAXS fibre scattering is used to map the microstructural properties of single carbon fibres, ranging in diameter from 5 to 8 µm. The new SAXS/WAXS beamline end station upgrade has made feasible to measure single carbon fibre monofilaments thanks to the high incident flux and extremely low background provided by a new high-vacuum sample environment. Based on an automated scanning protocol, a single carbon fibre is aligned relative to the incident X-ray beam (beam size H: 250 µm × V: 25 µm). The fibre is mounted in vacuum while points on each monofilament are acquired. This scanning protocol ensures that the fibre scattering cross-section in known precisely. The size of the detector allows both a SAXS and WAXS signal to be recorded in a single image. Furthermore, it is now possible to increase the sample-to-detector distance automatically, making low q-SAXS practical on these samples for the first time, and without having to remount or interfere with sample condition. The technique allows both the size and alignment of the microstructural features from fibre-to fibre to be quantified. Importantly, the graphitic alignment, spacing and apparent crystallite size can be directly related to macroscopic mechanical properties. While quantitative analysis of the SAXS scattering signal from pores trapped within the fibre provides an indication of macroscopic strength. Results are presented for carbon fibres prepared on the Carbon Nexus facility at Deakin University.

        Speaker: Pablo Mota-Santiago (Deakin University, Australian Synchrotron)
      • 14:35
        Solving industry problems using neutrons - 5 years of the Industrial Liaison Office at the Australian Centre for Neutron Scattering 15m

        The OPAL research reactor at ANSTO has several instruments available for materials science and engineering applications. The instruments have a unique non-destructive ability to assist academia and industry in solving industry relevant problems. The role of the Industrial Liaison Office (ILO) at the Australian Centre for Neutron Scattering (ACNS) focuses on connecting and advocating ACNS innovation and expertise with external collaborators and clients. The goal of ILO ACNS is to support Australian and global industry through building long-term collaborations and partnerships with universities, other research organisations, and businesses. Our portfolio includes developing commercial and scientific research programs that utilize neutron technology to support Australian and global industry.
        Those neutron measurements can be carried out on real engineering components, or test samples with minimal preparation. This information provides direct impact into optimization of modern manufacturing processes, improved product reliability, enhanced design performance, reduced production cost, and extended life of significant engineering assets (e.g. power-station utilities, gas pipelines, aircrafts, trains, etc.).
        This presentation will celebrate achievements an of the ACNS team over the last five years of operation and show case how you can use neutron instrument to solve material and engineering problems to assist industry in solving modern challenges.

        Speaker: Anna Paradowska (ANSTO)
    • 14:00 → 14:30
      Session 5: Technique Development - T11 (Part 2)
      • 14:00
        Australian Centre for Neutron Scattering Update 15m

        The Australian Centre for Neutron Scattering (ACNS) utilises neutrons from Australia’s multi-purpose research reactor, OPAL, to solve complex research and industrial problems for Australian and international users via merit-based access and user-pays programs. Neutron scattering techniques provide the research community and industry with unique tools to study the structure, dynamics and properties of a range of materials, helping scientists understand why materials have the properties they do, and helping tailor new materials.

        An update will be given on the OPAL reactor and its neutron beam facilities, the status of the neutron beam instruments and supporting capabilities, user program, and future plans.

        Speaker: Jamie Schulz (ANSTO)
      • 14:15
        BioSAXS: the new solution scattering beamline at the Australian Synchrotron 15m

        The BioSAXS beamline is one of the new beamlines to be constructed at the Australian Synchrotron within the BRIGHT program. BioSAXS will be dedicated to perform solution small angle scattering (SAXS) experiments, offering access to a variety of researchers from Australia and New Zealand. Solution SAXS experiments continue to be a growing area of the current Australian Synchrotron SAXS/WAXS operations, particularly in regard to protein and DNA/RNA structure, polymer solutions, nanoparticles and liquid crystal phases. In addition, the structural biology and soft matter work comprise some of the most productive areas of research in the Australian Synchrotron scattering community. The BioSAXS beamline will allow highly radiation sensitive samples to be studied using unprecedented levels of flux, using the CoFlow sample environment, a pioneering development of the Australian Synchrotron. The BioSAXS beamline aims to accommodate most solution SAXS experiments for a wide range of particle sizes by offering a q-range of ~ 0.001 – 3 Å-1, with low instrument background and an optical design optimized for high flux (>1014 ph/s) x-rays and a focused beam size of 0.3 mm (H) x 0.03 mm (V). The implementation of BioSAXS beamline, in conjunction with the existing SAXS/WAXS beamline, will ensure that the SAXS offering at the Australian Synchrotron is at the forefront of world leading SAXS measurements.

        Speaker: Christina Kamma-Lorger (Lead Scientist BioSAXS)
    • 14:00 → 14:30
      Session 6: Chemistry and crystallography - T3 (Part 2)
      • 14:00
        Unexpected Phase Transitions in AMO4 scheelites. 15m

        The vast majority of solid state oxides contain transition metals in an octahedral, or a distorted variant thereof, environment and the interconnectivity and distortions of the MO6 units drive their interesting and occasionally technologically important physical properties. Oxides where the transition metal has a tetrahedral geometry are less well studied. The Scheelite structure is one such example and this presentation will describe some of our recent studies on two classes of scheelites; the 3:5 oxides Ln3+Nb5+O4 and the 1:7 oxides A1+M7+O4 (A = Ka, Rb, Cs, Tl; M = Tc, Ru, Re and Os).
        The synthesis, structures and magnetic properties of the Ru and Os salts AMO4 (A = K, Rb and Os) are described. Both K salts adopt the ideal tetragonal Scheelite structure and contain isolated MO4 tetrahedra. Both show AFM ordering along [001] described by k = 000 at low temperature and neutron diffraction measurements reveal a reduced moment ~ 0.5 μβ due to a combination of covalency and spin-orbit coupling. RbOsO4 displays the same tetragonal structure and is an antiferromagnet with TN ~ 20K. RbOsO4 has an orthorhombic structure in Pnma as a consequence of rotations of the OsO4 and this transforms to the tetragonal structure upon heating above 400 K; both Rb salts are AFM. At room temperature the two Cs salts are both orthorhombic and both undergo additional transitions upon cooling.
        Temperature dependent structural studies of ATcO4 (A = Ag, Tl, Rb and Cs) from 90K to their melting points reveal unexpected phase transitions in RbTcO4 that displays a I41/a to I41/amd transition and in TlTcO4 where the orthorhombic (Pnma) to tetragonal (I41/a) transformation proceeds via an intermediate orthorhombic phase. Like the Ru and Os oxides CsTcO4 undergoes a first order orthorhombic (Pnma) to tetragonal (I41/a) transition upon heating.

        Speaker: Brendan Kennedy (The University of Sydney)
      • 14:15
        Chemical Crystallography with neutrons at OPAL - KOALA fulfils a promise 15m

        A strong case for the inclusion of a single-crystal diffractometer was made in the scoping of the initial suite of instruments to be built at the OPAL Reactor facility. The choice of a Laue instrument appeared to offer significant opportunities for a broad community of potential users. In particular the potential to undertake single-crystal chemical crystallography experiments on crystals of sizes less than a cubic millimetre was a particular attraction of using Laue diffraction. The instrument procured was largely based on the VIVALDI instrument which was being implemented at the Institut Laue Langevin in Grenoble, France.

        By the time our instrument, KOALA was available for users, the world-wide output of single-crystal chemical crystallography studies (as included in the Cambridge Data Base) from the various neutron sources had, for a range of reasons, slowed to a trickle. This was despite the availability of several instruments which had promised a significant increase in the availability of such studies for application in areas of chemistry where definitive characterization of materials could only properly be achieved by this means.

        The implementation of KOALA at ANSTO is compatible with applications to many fields of science, those in the physics applications had been strongly developed at the various neutron facilities across decades, whilst the applications in chemistry still had considerable scope to develop. Two critical developments at ANSTO have been the implementation of Oxford Cryosystems COBRA™ cryostream technology (developed for X-ray Crystallography). This has facilitated the examination of crystals under conditions compatible with their chemical and physical properties.

        The most important development has been the creation of the LAUEG suite by Dr Ross Piltz which facilitates straightforward extraction of a data file in a format which chemical crystallographers are accustomed to use for routine crystals, and a suite of tools to manage the processing in non-routine cases.

        I the first ten years of operation, it has been possible to build a strong chemical crystallography single-crystal neutron diffraction activity with KOALA. From the outset publications results from KOALA have appeared in the primary reports of the chemistry in high impact journals. More recently, as the capabilities of the instrument have become more widely known, access to KOALA has been sought to undertake key studies which underpin publication in journals of the highest standing.

        Many of our users have little prior experience of neutron scattering, and at times, their exposure to crystallography has also been of limited extent. Four student theses have relied heavily on data collected at KOALA and all these students have proceeded to careers in which their well developed critical and analytical skills are required

        This talk will highlight the important papers and findings which have reached the literature to date from KOALA with emphasis on what the single-crystal neutron diffraction experiment added to the chemistry under study.

        Speaker: Alison Edwards (ACNS, ANSTO)
    • 14:30 → 15:05
      Session 7: Structural biology and biological systems - T5
      • 14:30
        Synchrotron techniques in environmental and agricultural science: the advantages of higher throughput and enhanced sensitivity 20m

        A number of synchrotron-based techniques are increasingly being used to investigate nutrients and contaminant metals in a variety of environmental and biological samples. The advantages of these techniques are well known: minimal sample preparation (e.g. reduce risk of artefacts), high lateral and spatial resolution, ability to probe the speciation of elements in situ. However, until recently, synchrotron techniques have been considered generally ‘slow’ and not particularly sensitive in comparison with other methods providing very detailed information on a few samples at reasonably high concentrations. This has changed. The advent of fast and sensitive detector technologies has completely transformed the way we approach synchrotron experiments and the information we can obtain. For instance, traditionally, X-ray Fluorescence (XRF) elemental mapping has been used to gain an understanding of metal distribution while X-ray Absorption Spectroscopy (XAS) has been employed to investigate metal speciation. This latter approach has been performed at both the ‘bulk’ and microscale; these two approaches being complementary and providing different information. However, in the last few years, the development of a new generation of fast fluorescence detectors providing unprecedented rates of data acquisitions is blurring the divide between imaging and speciation techniques due to the developments of methods such as XANES-imaging (X-Ray Absorption Near Edge-imaging). Furthermore, fast detectors have allowed us to probe not just larger samples and more samples, they have also decreased the risk of beam damage, and, in-vivo time series experiments are now possible. At the same time, the development of ever more sensitive detectors and higher fluxes have enabled the analyses of trace element distribution and speciation at concentrations that are environmentally relevant. In this presentation we will discuss how new technologies have changed the information we can obtain from synchrotron experiments and how their design has changed over time. In particular, we will explore how the advances in a number of synchrotron techniques and their integration will provide new information not only in environmental science but also in agriculture. In the latter case, the ability to gain detailed information on large samples will provide a powerful avenue to add value to experiments conducted not only at laboratory scale but also at field scale.

        Speaker: Enzo Lombi (University of South Australia)
      • 14:50
        Molecular Deuteration at the National Deuteration Facility: Diversity of Molecules and Application 15m

        The National Deuteration Facility (NDF) at the Australian Nuclear Science and Technology Organisation (ANSTO) provides deuteration for a diversity of molecules and applications. Molecular deuteration of organic compounds and biomolecules significantly increases the options in complex structure function investigations using neutron scattering and reflectometry, nuclear magnetic resonance (NMR), mass spectrometry (MS) and other techniques. Deuterium (2H or D) is a naturally occurring stable isotope of hydrogen (1H or H). Deuteration can provide contrast and improved resolution to assist investigations into the relationship between molecular structure and function of molecules of both biological and synthetic origin.

        The NDF at ANSTO is the only facility of its type in the Southern Hemisphere, having the specialised expertise and infrastructure for both biological and chemical molecular deuteration. Access is available via a merit-based user program. Since the open access user program began in 2010 we have delivered over 280 different labelled molecules to collaborators.

        The NDF has developed a suite of capabilities in both in vivo deuteration of biomolecules and chemical deuteration of small organic molecules providing access to a broad range of deuterated molecules for research and industry. Variably deuterated proteins can be produced via simple defined yet robust NDF-developed methods of high-yield recombinant expression in Escherichia coli. Multiply-labelled (2H, 13C, 15N) proteins are also produced via these protocols for NMR applications. The development of chemical deuteration protocols for a broader range of molecular classes unavailable commercially and a tailoring of deuteration approach has increased the range of systems that can be investigated using deuterated molecules. Lipids, phospholipids (including head or tail or head/tail deuterated mono-unsaturated lipids such as POPC and DOPC), heterocyclics, aromatics, surfactants, ionic liquids, sugars and match-out detergents have been deuterated. Common neutron applications include partially deuterated proteins for SANS experiments investigating multi-protein systems, neutron crystallography of perdeuterated proteins, neutron reflectometry of lipid bilayers systems and SANS using saturated lipid vesicles, or detergents amongst others. Microbial systems have also been recently utilised to produce deuterated cellulose and cholesterol, expanding the range of biosynthesised molecules available.

        Recent advancements and the impact of deuteration on the research outcomes achieved by using deuterated molecules produced by the NDF will be presented through case studies [1-3] highlighting the diverse applications that benefit from availability of custom deuterated molecules.

        [1]. Disulfide isomerase activity of the dynamic, trimeric Proteus mirabilis ScsC protein is primed by the tandem immunoglobulin-fold domain of ScsB. Furlong, E. J., Choudhury, H. G., Kurth, F., Duff, A. P., Whitten, A. E. & Martin, J. L. Journal of Biological Chemistry, 293, 5793-5805. (2018)
        [2]. Transient antibody-antigen interactions mediate the strain-specific recognition of a conserved malaria epitope. Krishnarjuna, B., Sugiki, T., Morales, R. A. V., Seow, J., Fujiwara, T., Wilde, K. L., Norton, R. S. & MacRaild, C. A. Communications Biology, 1, 58. (2018)
        [3]. Controlled deuterium labelling of imidazolium ionic liquids to probe the fine structure of the electrical double layer using neutron reflectometry. Akutsu-Suyama, K., Cagnes, M., Tamura, K., Kanaya, T. & Darwish, T. A. Physical Chemistry Chemical Physics, 21, 17512-17516. (2019)

        Speaker: Karyn Wilde (ANSTO)
    • 14:30 → 15:00
      Session 8: Earth, interstellar and extreme environments - T8
      • 14:30
        In situ XAS measurement of silicate liquids using the high pressure and temperature D-DIA facility at the Australian Synchrotron 15m

        Geochemical variation in the Earth, such as the chemical differences between the core, mantle and crust, are fundamentally explained through understanding of how elements
        are partitioned amongst metals, minerals and melts over a wide range of pressures, temperatures, and redox conditions. The dominant framework for considering trace element behaviour in mineral/silicate-melt systems is the lattice strain model that considers
        substitution of size and charge mismatched elements into crystals in terms of distributing excess elastic and electrostatic energy throughout the crystal lattice. However, the lattice strain model disregards changes in melt structure. Abundant experimental evidence demonstrates that cations in silicate liquids begin increasing average coordination numbers at pressures as low as ~ 3 GPa. Changes in silicate liquid structure with pressure (polyamorphism) is a possible cause. Speciation (coordination and valence state) of metal cations in silicate liquids is not always faithfully preserved in glasses upon quenching.
        There are few extant in situ studies of element coordination as a function of pressure in liquids or glasses, and even fewer applying XAS. Without high quality in situ measurements, it is difficult to determine the utility of speciation data collected from quenched glasses, or glasses annealed at high pressure. Here we present experimental results aimed at understanding the speciation of key trace cations in geologically relevant silicate melts, in situ, at high pressure and temperature.
        In-situ studies are critical as we can directly investigate chemical behaviour in melts, not glasses, which likely do not fully preserve the liquid structure upon quenching.

        Speaker: Tracy Rushmer (Macquarie University)
      • 14:45
        In-situ synchrotron X-ray tomographic study of stress-dependent porosity and permeability behaviour of fractured coal 15m

        Coal seams are characterised as fractured reservoirs, consisting of natural fractures/cleats running through the coal matrix. The porosity and permeability of fractured coal are highly stress-sensitive. A bundled matchstick model is widely used to describe the cleat system. Based on this model, the well-known cubic law can describe the permeability change in response to fracture porosity/aperture change. However, this correlation is problematic, since the matchstick model assumes that fractures can be adequately represented as parallel plates with a constant aperture. In fact, fractures appear in all sizes with their apertures being rough and variable. In addition, although fracture properties, such as aperture distribution, tortuosity and connectivity, are affected by changes in stresses, the effect of stresses on the fracture properties and thus permeability has not yet been well studied. In this study, in-situ synchrotron X-ray tomography was conducted on a fractured anthracite coal at a resolution of 18.1 μm using a novel X-ray transparent tri-axial cell. We provided a detailed characterization of the fracture network and permeability change due to increased effective stress from 0.5 to 11.0 MPa. Results show that the permeability decreased by one order of magnitude following an exponential function. Large fractures were quickly compressed and isolated to smaller fractures and the fracture contact areas increased in response to increased stresses. Preliminary studies on the correlation between permeability and CT-resolved porosity/aperture is not consistent with the cubic law. This may indicate that fractures cannot be adequately represented as smooth parallel plates. A mixture of tube and plate model is proposed to better describe fracture geometry considering its rough nature.

        Speaker: Mr Guanglei Zhang (Monash University )
    • 15:05 → 15:30
      Afternoon Tea 25m
    • 15:30 → 16:45
      Session 10: Structural biology and biological systems - T5 (Part 2)
      • 15:30
        Using Neutron Reflectometry to Understand Antibiotic Resistance in Gram-negative Bacteria at the Outer Membrane 15m

        With bacteria increasingly becoming resistant to common antibiotics, we are currently heading for a post-antibiotic world, where treatable common aliments are suddenly untreatable. This means that there is now considerable research effort in understanding how antibiotic resistance arises, and in creating a new generation antibiotics. The outer membrane is the first line of defence against antibiotics for Gram-negative bacteria. Being able to penetrate the outer membrane is essential to designing effective antibiotics and antimicrobial peptides. The outer membrane is an asymmetric bilayer consisting of phospholipids on its lower leaflet and lipopolysaccharides on its environment-facing outer leaflet. This work will present on creating model outer membranes from Pseudomonas aeruginosa, a bacterium that is normally harmless, but infections from which can prove to be problematic for those that are immunocompromised. Worryingly, P. aeruginosa is showing increasing signs of becoming resistant to Polymixin B, an antibiotic of last resort. Certain biochemical modifications to lipid A (a component of lipopolysaccharides) can confer resistance to Polymixin B in P. aeruginosa strains. Model P. aeruginosa outer membranes using lipid A with different modifications were created on silica surfaces using Langmuir-Blodgett and Langmuir-Schaefer deposition techniques. Model outer membranes created this way are ideal tools for studying the binding antimicrobial peptides because: a) they reflect the lipid composition of the membrane, b) reflect the fluidity of the membrane, and c) maintain the asymmetric nature of the outer membrane. The nanoscale structures of the membranes were determined using neutron reflectometry and it was observed that Polymixin B was unable to penetrate into bilayers that consist of de-acylated lipid A. New drug targets Octapeptin A3 [1], and modified Polymixins FADDI-019 and FADDI-020 [2] were tested and found to disrupt membranes composed of modified lipid A which confer resistance to Polymixin B.

        [1] M.-L. Han et al., ACS Infect. Dis. 3, 606 (2017)
        [2] M.-L. Han et al., ACS Chem. Biol. 13, 121 (2018)

        Speaker: Anton Le Brun (ANSTO)
      • 15:45
        Understanding MLKL’s molecular switch mechanism using two novel MLKL pseudokinase orthologue structures 15m

        Necroptosis is a form of programmed cell death characterized by lack of caspase activity and a loss of plasma membrane integrity. Morphologically similar to necrosis, during necroptosis, the plasma membrane is disrupted, causing release of cellular components to the extracellular fluid and an ensuing inflammatory response. Necroptosis proceeds via a regulated kinase cascade involving Receptor Interacting Protein Kinases RIPK1 and RIPK3. Mixed Lineage Kinase domain-Like protein (MLKL), a pseudokinase, is the final known obligate effector of necroptosis. The MLKL pseudokinase domain is incapable of catalysing phosphotransfer reactions, and is the site of RIPK3 phosphorylation. This phosphorylation event is thought to flip a molecular switch regulated by the pseudokinase domain, resulting in activation of MLKL. Upon activation, MLKL oligomerises, translocates to the plasma membrane, and destabilises it. Details of MLKL’s molecular mechanism of action, including activation, oligomerisation and how it interacts with the plasma membrane, remain unknown.

        To interrogate MLKL’s molecular switch mechanism, we solved the structure of the pseudokinase domain of two MLKL orthologues; horse and rat, using X-ray crystallography at the Australian Synchrotron. By comparing the structure and sequence of the orthologues with previously published structures of mouse and human MLKL, we found that the novel conformations adopted in our structures may represent different stages of the molecular switch mechanism, with different conformations favoured for each orthologue due to sequence variation. We paired these findings with death assays in cells, to understand the commonalties between orthologue necroptotic signalling pathways and undertook mutational analysis to understand the significance of the conformations found in our structures.

        Speaker: Katherine Davies (The Walter and Eliza Hall Institute of Medical Research)
      • 16:00
        Elucidating the mechanisms of small molecule cryoprotection using Neutron Membrane Diffraction 15m

        The interaction between membranes and small molecules is a key factor in determining survival of organisms or cells during dehydration and/or freezing. Cryoprotective molecules fall into two categories: those important in desiccation and freezing tolerance in nature (such as sugars), which cannot pass through membranes; and penetrating molecules, such as DMSO, which are used in laboratory cryopreservation. Both types of molecules affect membrane structure, but the interactions, and therefore cryoprotective mechanisms, are different.

        To understand these mechanisms we have previously studied the structure of synthetic membranes in the presence of small sugars using SAXS and SANS [eg 1-2]. More recently we have used membrane diffraction, which yields higher order diffraction peaks, allowing Fourier reconstruction of the bilayer structure [3-4]. These experiments are conducted on stacked multilamellar membranes (with and without the relevant molecules) under partially dehydrated conditions (relevant to desiccation and freezing). By deuterating one or more components, and adjusting the neutron contrast of the water by changing the D2O/H2O ratio, it is possible to isolate the locations of the molecules in the bilayer region with high precision.

        Using the cold triple axis spectrometer MIRA [5] (MLZ, Garching, Germany) we have optimised these measurements for the number of higher order diffraction peaks under conditions of contrast variation. Each subsequent peak, and Fourier term, provides improved spatial resolution and diminishes the effects of truncation artefacts in Fourier series.

        We have recently extended these measurements to systems containing DMSO. In this talk we will present these results, and use them to contrast the different modes of action of the two classes of cryoprotective molecules. The implications for our understanding of cryopreservation will be discussed.

        [1] C.J. Garvey, T. Lenné, K.L. Koster, B. Kent, G. Bryant Int. J. Molecular Sciences 14, 8148 (2013).
        [2] B. Kent, C.J. Garvey, T. Lenné, L. Porcar, V.M. Garamus, G. Bryant Soft Matter 6, 1197 (2010).
        [3] B. Kent, T. Hunt, T.A. Darwish, T. Hauß, C.J. Garvey, G. Bryant J. Royal Soc. Interf. 11, 20140069 (2014).
        [4] B. Kent, T. Hauß, B. Demé, V. Cristiglio, T. Darwish, T. Hunt, G. Bryant, C.J. Garvey Langmuir 31, 9134 (2015).
        [5] R. Georgii, T. Weber, G. Brandl, M. Skoulatos, M. Janoschek, S. Mühlbauer, C. Pfleiderer and P. Böni, Nucl. Instr. Meth. Phys. Res. A 881, 60-64 (2018).

        Speaker: Gary Bryant (Centre for Molecular and Nanoscale Physics, School of Applied Sciences, RMIT University)
      • 16:15
        Flexibility of Lipid Bilayer Membranes in Ionic Liquids 15m

        Ionic liquids (ILs) are a novel class of solvents with ultra-low vapour pressure and tunable liquid properties. Among them, protic ionic liquids (PILs) are particularly effective solvents for self-assembly of surfactants and lipids into micelles, vesicles, liquid crystals and microemulsions.[1-4] This is exemplified by alkylammonium PILs, which are also cheap, easily-prepared and can be readily deuterated. Over the past decade, much is learnt about the static structure of many ethylammonium PILs,[5] however, virtually nothing is known about their dynamics or of how the underlying nanostructure of the IL solvent affects the dynamic of amphiphile aggregates. In this work, we aim to reveal the effect of solvent nanostructure on flexibility of lipid bilayers. We employed neutron spin echo spectroscopy (IN15, ILL) to probe the mesoscopic undulation of Egg-PC membranes (1 wt% as vesicle dispersions) in ethylammonium formate (EAF) and water. For the first time, IN15 is configured to perform dynamic measurements up to 1000 ns, which is essential due to the much slower motion we observed in PILs. Through the comparison between EAF and water, we are able to elucidate the dominant factor that affects membrane stiffness and stability in ILs, and how EAF nanostructure contribute to the dynamics of large amphiphile aggregates.

        1. M.U. Araos, G.G. Warr, J. Phys. Chem. B. 2005, 109, 14275-14277
        2. M.U. Araos, G.G. Warr, Langmuir 2008, 24, 9354-9360.
        3. R. Atkin and G.G. Warr, J. Phys. Chem. B. 2007, 111, 9309-9316.
        4. S.J. Bryant, K. Wood, R. Atkin, G.G. Warr Soft Matter 2017, 13, 1364-1370
        5. R. Hayes, G.G. Warr, R. Atkin Chem. Rev. 2015, 115, 6357-6426.
        Speaker: Shurui Miao (The University of Sydney)
      • 16:30
        TheStructure of the Murine CD94/NKG2A Complex Reveals Convergence With the Human Homologue 15m

        Natural Killer cells are immune effectors that clear viruses and malignancies through the gain of recognition of “altered self (stress)” molecules or through the loss of recognition of “healthy self” molecules on the target. The heterodimeric CD94-NKG2A receptor is an inhibitory receptor that monitors global MHC class I expression levels through binding to MHC class Ia-derived leader sequence peptides presented by HLA-E (in humans) or Qa-1b (in mice). In so doing, CD-NKG2A monitors for “healthy self”. Viruses and malignancies that down-regulate MHC-Ia expression to evade recognition by the T-cell arm of the adaptive immune system are thus vulnerable to natural killer cell clearance through “dis-inhibition” of CD94/NKG2A. This system of “immune cross-checking” has made the CD94/NKG2A system a promising target for therapeutic intervention with a number of check-point inhibitor antibodies that target CD94/NKG2A currently in clinical development. In this study we determined the high-resolution crystal structure of murine CD94-NKG2A in complex with Qa-1b presenting the Qa-1 determinant modifier (Qdm) peptide, and thus provide the mode of binding in mouse. Through comparison with the human homologue we show that despite an overall similar binding mode, recognition of Qa-1b by murine CD94-NKG2A occurred via altered electrostatic complementarity. These data show how human and murine CD94-NKG2A have co-evolved with HLA-E and Qa-1b which exhibit cross-species heterogeneity yet exhibit highly similar function. This has important implications for understanding differences in the model murine system compared to the human for the clinical progression of disease.

        Speaker: Dr Julian Vivian (Monash Uni.)
    • 15:30 → 16:30
      Session 11: Earth, interstellar and extreme environments - T8 (Part 2)
      • 15:30
        How long was the LGM in East Antarctica? Insights from in-situ 14C dating of bedrock surfaces 15m

        The duration of ice advance and retreat in Antarctica provides insight into its overall sensitivity to environmental thresholds, the response time of the ice sheet to climate and sea level perturbations. While measuring the timing of ice retreat has become relatively routine through the advent of Be-10 exposure dating, determining the onset and the duration of glaciation remains difficult due to the challenges of obtaining pre-glacial sediments.

        The measurement of in-situ C-14 in bedrock surfaces provides a low-resolution temporal approach that enables an understanding of whether LGM ice cover was brief or extended across several tens of thousands of years. Here, we present new observations from Princess Elizabeth Land in East Antarctica that demonstrates differing responses of the inland and coastal portions of the ice sheet. Inland at Mt Brown, C-14 inventories in bedrock are consistent with a ‘long duration’ LGM, with the ice sheet remaining at the maximum limit for at least 15,000 years before thinning in the early Holocene. In contrast, ice advance in coastal regions at Rauer Group was brief, and the areal limit of the ice sheet was similar to or smaller than today for most of the past 40,000 years.

        This new evidence contributes to our understanding of the ‘relative sea level paradox’ recorded sediments around Prydz Bay, which indicate both an increased ice load, but aerially restricted ice extent during much of the last 40,000 years. However, it in turn points to a radically different behaviour of the ice sheet in response to climate and sea level forcing than had been previously understood.

        Speaker: Dr Duanne White (University of Canberra)
      • 15:45
        Multimodal, multiscale chemical and structural imaging of vein-formation processes 15m

        Veins are opening-mode fractures in rocks filled with minerals crystallised from a fluid injected during the cracking process. They occur throughout the entire lithosphere of our planet and constitute important fast fluid pathways in otherwise dense, impermeable rock1. In addition, veins trap precious ores such as gold and are routinely targeted by the resource industry2,3. Moreover, microstructure and mineral texture of vein-forming minerals serve as invaluable recorders of the tectonic history of rock evolution, the state of stress and temperature during emplacement as well as fluid chemistry and fluid-rock interaction1,4-6. Hence, micro- and nano-analytical methods hold the key to understanding the physics and chemistry of vein-formation processes.

        Here, we show how selected applications of Synchrotron XFM, ptychography, and SAXS/WAXS unveil quantitative micro- and nano-textures of calcite veins, which are invisible to conventional imaging techniques. The Synchrotron's unique ability to map trace chemistry and structures over more than four orders of magnitude in length scale inspires unprecedented insights into the multi-scale physics of coupled chemical, mechanical, hydraulic and thermal processes in rocks and other reactive, porous solids. This multi-physics, multi-scale coupling constitutes one of the principal research challenges in the Earth and Material Sciences7,8.

        1 Bons, P. D., Elburg, M. A. & Gomez-Rivas, E. A review of the formation of tectonic veins and their microstructures. Journal of Structural Geology 43, 33-62 (2012).
        2 Cox, S. F. & Ruming, K. The St Ives mesothermal gold system, Western Australia—a case of golden aftershocks? Journal of Structural Geology 26, 1109-1125 (2004).
        3 Tomkins, A. G. On the source of orogenic gold. Geology 41, 1255-1256 (2013).
        4 Blenkinsop, T. G. Relationships between faults, extension fractures and veins, and stress. Journal of Structural Geology 30, 622-632 (2008).
        5 Haertel, M., Herwegh, M. & Pettke, T. Titanium-in-quartz thermometry on synkinematic quartz veins in a retrograde crustal-scale normal fault zone. Tectonophysics 608, 468-481, doi:10.1016/j.tecto.2013.08.042 (2013).
        6 Putnis, A. Mineral Replacement Reactions. Reviews in Mineralogy and Geochemistry 70, 87-124 (2009).
        7 Regenauer-Lieb, K. et al. Multiscale coupling and multiphysics approaches in earth sciences: Theory. Journal of Coupled Systems and Multiscale Dynamics 1, 49-73 (2013).
        8 Regenauer-Lieb, K. et al. Multiscale coupling and multiphysics approaches in earth sciences: Applications. Journal of Coupled Systems and Multiscale Dynamics 1, 281-323 (2014).

        Speaker: Michael Jones (QUT)
      • 16:00
        Two birds with one stone: leaching of alkaline mineral wastes enhances CO2 sequestration and concentrates trace metals 15m

        The mineral wastes produced by ultramafic mines (i.e. Cu–Ni–PGE, podiform chromite, diamondiferous kimberlite and historical chrysotile) are ideal materials for sequestering CO2 via mineral carbonation. This natural process traps atmospheric CO2 in mineral form via weathering of Mg or Ca-rich silicate and hydroxide minerals to form Mg-carbonate. Due to a higher surface area, mineral carbonation of mine tailings typically occurs at rates 2-3 orders of magnitude above background rock weathering rates, and at the Mt Keith Ni Mine, WA, offsets 11% of the mine’s annual CO2 emissions.(1) If geochemical treatments were applied to these materials, reaction rates could be further accelerated such that a mine could potentially achieve carbon neutrality. In order to encourage uptake of mineral carbonation technology at mine sites, treatments will ideally make use of relatively conventional technology and expertise within the minerals industry. As such, in situ heap leaching is proposed as a potential strategy to accelerate mineral carbonation. Here, we simulate this process in column experiments, by leaching ultramafic tailings from Woodsreef Chrysotile Mine (NSW, Australia) with dilute sulphuric acid (pH ≈ 1). An alkaline leachate rich in Mg is produced with the potential to sequester 21.4 kg CO2 m-2 of treated tailings per year, which is approximately 1-2 orders of magnitude higher than estimates of passive carbonation that has occurred within these tailings over the past three decades.(2)
        Importantly, synchrotron X-ray fluorescence microscopy shows concentration of Ni, Co and Cr within Fe-(oxy)hydroxides at the neutralisation horizon, and geochemical modelling indicates that with continued acid leaching this horizon would become enriched in transition metals over time, concentrating metals of potential economic benefit in distinct zones within the vertical profile.
        Acid heap-leaching technology could therefore not only be useful for accelerated mineral carbonation but also for ore processing and recovery of base metals from tailings, waste rock, or low-grade ores.

        REFERENCES
        1) Wilson S.A. et. al. (2014) International Journal of Greenhouse Gas Control 25, 121-140.
        2) Turvey C.C. et. al. (2018) International Journal of Greenhouse Gas Control 79, 38-60.

        Speaker: Dr Jessica Hamilton (Australian Synchrotron (ANSTO))
    • 15:30 → 16:45
      Session 9: Food, pharmaceuticals and radiotherapy - T6
      • 15:30
        Lipid Self-assembly in Digesting Milk-like Emulsions 15m

        Milk is nature’s emulsion for delivering fats and fat-soluble nutrients to infants and remains a mainstay of the adult diet thereafter for many. The milk fat globules that deliver these nutrients comprise 98% triglycerides with 400 unique acyl chains esterified onto the glycerol backbones, resulting in thousands of possible unique triglycerides.[1] Digestion of triglycerides into monoglycerides and fatty acids by endogenous lipases breaks down the milk fat globules and allows the absorption of fat-soluble nutrients in the intestines. Small angle X-ray scattering (SAXS) with in situ lipolysis has revealed that the amphiphilic milk fat digestion products spontaneously assemble into a progression of liquid crystalline structures during in vitro lipolysis, with milk from different species yielding different self-assembled structures that are robust to standard processing techniques for milk storage.[2-4] SAXS has also shown that lipolysis can enhance the solubility of crystalline lipophilic drugs in digesting milk and infant formula preparations, which commonly limits their bioavailability.[5-7] We hypothesise that the liquid crystalline structures that form are advantageous for nutrient absorption by each individual species and that controlling liquid crystalline structure formation during digestion is key to nutrient delivery. A key issue in testing this hypothesis is the chemical complexity of the milk fats themselves, making the analysis of chemical-structure-function relationships challenging. This presentation will discuss the lipid liquid crystalline structures formed in a variety of milks and milk-like emulsions during digestion and how they can be mimicked with simplified triglyceride emulsions that provide representative digestive colloid structures through which to analyse the impact of lipid digestion on bioactive delivery. Lipid self-assembly in digesting mammalian milks and milk-like emulsions measured using SAXS will be discussed in the context of their lipid compositions.

        References
        [1] Fox, P. F.; McSweeney, P. L. H., Advanced Dairy Chemistry Volume 2: Lipids. 3rd ed.; Springer US: New York, USA, 2006.
        [2] Salentinig, S. et al. Formation of Highly Organized Nanostructures during the Digestion of Milk. ACS Nano 2013, 7 (12), 10904-10911.
        [3] Salentinig, S. et al. Self-Assembly Structure Formation during the Digestion of Human Breast Milk. Angew. Chem. Int. Ed. 2015, 54 (5), 1600-1603.
        [4] Clulow, A. J. et al. A closer look at the behaviour of milk lipids during digestion. Chem. Phys. Lipids 2018, 211, 107-116.
        [5] Boyd, B. J. et al. The impact of digestion is essential to the understanding of milk as a drug delivery system for poorly water soluble drugs. J. Controlled Release 2018, 292, 13-17.
        [6] Salim, M. et al. Application of Low-Frequency Raman Scattering Spectroscopy to Probe in Situ Drug Solubilization in Milk during Digestion. J. Phys. Chem. Lett. 2019, 2258-2263.
        [7] Binte Abu Bakar, S. Y. et al. Revisiting dispersible milk-drug tablets as a solid lipid formulation in the context of digestion. Int. J. Pharm. 2019, 554, 179-189.

        Speaker: Andrew Clulow (Monash University)
      • 15:45
        Using nuclear techniques to investigate the plant absorption and mobility of foliar applied zinc 15m

        In this agricultural focused study, we accessed ANSTO’s Open Pool Australian Lightwater (OPAL) reactor and Australian Synchrotron (AS) to investigate the efficacy of new fertiliser products. As well as accessing these facilities, we also used multiple ANSTO Research Capabilities (Sydney) to investigate the behaviour of these fertilisers in live plants; specifically, the Vivarium; Radiobiology and Bioimaging; Isotope Tracing; Nuclear Stewardship; and, Nuclear Materials Development and Characterisation. All fertilisers tested in this study were applied to plants to provide zinc (Zn). Zinc is an essential plant micronutrient, and in Australia it is often applied to broadacre crops as Australian agricultural soils are some of the most Zn deficient globally. To supplement soil applications of Zn fertiliser, Zn can also be applied directly to the foliage of crops; it is this application method that was the focus of our study. The development of more efficient foliar Zn fertilisers is beneficial not only to growers, who will have a reduced outlay for Zn fertiliser, but also for the environment as some chelated Zn formulations may pose a risk to aquatic and terrestrial systems.
        The objective of our study was to investigate the efficacy of novel Zn foliar fertilisers when applied to wheat plants. Conventional analytical techniques were found to be unsuitable for this study because the applied Zn could not be distinguished from background Zn in the plant. Therefore, by using Zn foliar fertilisers radiolabelled with 65Zn we were able to quantify and visualise the plant absorption and translocation of foliar applied Zn. Two newly developed Zn fertilisers; a nanoparticle formulation and a microparticle formulation were compared to two conventional formulations (soluble Zn and chelated Zn). Fertilisers were neutron activated at ANSTO’s OPAL reactor to produce 65Zn labelled foliar fertilisers. We then used a novel time-resolved in vivo autoradiography imaging technique to visualise 65Zn in live plants. The images were supplemented by gamma-spectroscopy analysis for quantification. The distribution of applied 65Zn in wheat grain was then compared to that of unlabelled Zn using X-ray fluorescence (XRF) elemental mapping. The results of this study describe a new method for investigating the mobility and translocation of foliar applied Zn, and potentially other nutrients, in plants.

        Speaker: Casey Doolette (University of South Australia)
      • 16:00
        Nuclear techniques for combating food fraud and authenticating quality 15m

        According to World Health Organisation of the United Nations, approximately 600 million people are affected by food contamination, which leads to around 420,000 deaths per year. Human health has been placed at risk by the presence of pathogens and other chemical substances found in food. Australia is one of the leading importers and exporters in the Australasian region. However, importing and exporting food can lead to food fraud. This is when fraudulent businesses substitute produce, along the supply chains, with ones of lower value and quality in order to increase profit margins. This type of food fraud is estimated to cost the global food industry between $30 to $40 billion USD per annum. Consequently, food safety and traceability are increasingly important to regulatory bodies, the industry and consumers. While several methods are available to combat this widespread issue, there are no comprehensive techniques which can accurately determine both the production methods and geographic origins of food.

        To combat food fraud and authenticate quality, the Australian Nuclear Science and Technology Organisation (ANSTO) is leading a food provenance research project in partnership with universities, industry and government agencies in order to develop a tool that will determine the source and origin of produce and authenticate quality. ANSTO is in a unique position where its multi-platform capability can play a vital role in food safety and traceability. Nuclear techniques such as stable isotope analysis, x-ray fluorescence through Itrax, neutron activation analysis and ion beam analysis can provide greater precision than conventional methods when determining the provenance of food. The specific isotopic and elemental fingerprints of a product can be linked to the location where it was produced. The initial testing of the technology on seafood produce and bushfood found that it could authenticate provenance with greater than 80% accuracy overall.

        The collaborating organisations are now working to improve the efficiency of their methods in conjunction with cutting edge food quality analyses through the support of the National Measurement Institute. This research will help regulatory bodies to scientifically-validate the source of origin of food and assess its quality. Furthermore, this method can serve as a marketing and brand protection tool. A large amount of Australian produce is exported overseas and sold as high-quality produce, where it can be subject to fraud. This method will help Australian industries in protecting their unique brand. Authenticating the origin and production methods of food will also allow consumers to make informed decisions and help them support their local industries.

        Speaker: Prof. Neil Saintilan (Macquarie University)
      • 16:15
        Gamma irradiated vaccines: concepts and applications 15m

        Gamma irradiation has widely been used to inactivate highly dangerous pathogens such as the Ebola virus and anthrax spores from Bacillus anthracis. It has also been used as an inactivation method to create whole “killed” bacterial or viral vaccines that induce broader spectrum immunity compared to vaccines inactivated by either chemical or other physical means. We have previously reported the cross-protective immunity induced by gamma-irradiated influenza vaccine (γ-FLU) and pneumococcal vaccine (γ-PN) (1-3). Importantly, in 2015 the US Department of Defense reported inadequate inactivation of anthrax spores following exposure to γ-irradiation. This created the need for a much better understanding of the conditions and parameters required to achieve sterility of infectious materials for vaccine purposes. Supported by the Australian Institute of Nuclear Science and Engineering (AINSE), we investigated different factors affecting the sterility of γ-irradiated preparations. We generated inactivation curves for multiple pathogens (including Influenza A virus, Zika virus, Semliki Forest virus, and rotavirus) and our data illustrated variations in inactivation curves directly related to the nature of genetic materials and irradiation conditions. These variations in killing curves reveal an important gap in current mathematical formulae to determine sterilising doses for different pathogens. In addition, we investigated the structural integrity and immunogenicity of different vaccine preparations. This study is expected to enable further development of sterile highly effective gamma irradiated vaccines.

        1. David SC, Norton T, Tyllis T, Wilson JJ, Singleton EV, Laan Z, Davies J, Hirst TR, Comerford I, McColl SR, Paton JC, Alsharifi M. Direct interaction of whole-inactivated influenza A and pneumococcal vaccines enhances influenza-specific immunity. Nature Microbiology. 2019 Aug;4(8):1316-1327
        2. Babb R, Chen A, Hirst TR, Kara EE, McColl SR, Ogunniyi AD, Paton JC, Alsharifi M. Intranasal vaccination with γ-irradiated Streptococcus pneumoniae whole-cell vaccine provides serotype-independent protection mediated by B-cells and innate IL-17 responses. Clinical Science (Lond). 2016;130(9):697-710.
        3. Alsharifi M, Furuya Y, Bowden TR, Lobigs M, Koskinen A, Regner M, Trinidad L, Boyle BB, Müllbacher A. Intranasal flu vaccine protective against seasonal and H5N1 avian influenza infections. PLoS ONE. 2009; 4(4):e5336.
        Speaker: Mohammed Alsharifi (The University of Adelaide)
    • 16:30 → 16:45
      Session 12: T7 - Surface Science & Thin Films
      • 16:30
        Dye – TiO2 Interfacial Structure in Dye-Sensitized Solar Cells 15m

        Solar cells are a widespread, clean and renewable source of energy for humanity's growing power needs. An emerging type of solar cell based on natural dyes to harvest sunlight has been the subject of growing interest. Dye-sensitized solar cells (DSCs) are transparent, flexible, and made from low cost, readily available materials. Compared to traditional silicon-based solar cells, DSCs have higher efficiencies in ambient or dim light. DSCs can be harnessed in areas such as solar windows to generate electricity and offset power costs in buildings.
        The dye molecules used in this study are organic, and are structured as donor – linker – acceptor molecules. A range of different donor, linker and acceptor functional groups have been synthesized, including the addition of bulky hydrophobic alkyl chains.
        At the interface between dye molecules and titanium dioxide (TiO2) semiconductor, the adsorbed dye molecules harvest energy from light and enters an excited state. The photoelectron is injected into the TiO2 conduction band, where the electrical circuit begins. The dye – TiO2 interface is vital to the efficiency and performance of DSCs, but is poorly understood. This study investigates dye adsorption and packing arrangements at the TiO2 interface using X-ray reflectometry (XRR) and atomic force microscopy (AFM) instruments at ANSTO, Australia for organic dye structures with different donor and linker groups. Neutron reflectometry (NR) will examine the dye – TiO2 interfacial structure in the presence of solvent and electrolyte to probe the extent of dye – solvent and dye – electrolyte interactions in situ.
        By changing the dye chemical structure, linker groups and donor groups, a range of structures are observed at the surface. While XRR measurements reveal an adsorbed monolayer at the local scale (area ~ 1 cm2), AFM measurements detect small dye aggregates at the surface (area ~ 225 $\mu$m2) for all dyes except for the largest and sterically bulky dye studied. This study demonstrates the importance of dye structure on interfacial properties in DSCs, and may be used to design dyes to optimise properties and solar cell efficiencies, in turn developing DSCs towards full-scale commercialisation.

        Speaker: Samila McDonald (ACNS, ANSTO and Cambridge University, UK)
    • 16:45 → 17:15
      Plenary: UAC Winner
    • 17:15 → 17:45
      Plenary: ANBUG Winner
    • 18:00 → 21:00
      Welcome Function: Poster Slam & Function
      • 18:00
        EMU cold-neutron backscattering spectrometer at ACNS 1m

        EMU is the high-resolution neutron spectrometer installed at the OPAL reactor, ANSTO, which delivers 1 µeV FWHM energy transfer resolution for an accessible ±31 µeV energy transfer range. The spectral resolution is achieved by neutron backscattering from Si (111) on the primary and secondary flight paths, allowing up to 1.95 Å^-1 momentum transfer range. The spectrometer is well for suited quasi-elastic and inelastic neutron scattering studies, notably in the field of soft-condensed mater including biophysics and polymer science, chemistry and materials science, and geosciences.
        Most experiments since the start of operation late 2015 were carried out with standard cryo-furnaces (2 to 800 K temperature range). Spectrometer beam-time access is merit-based, thus welcoming as well experiments in other materials research areas, and including experiments that may require e.g. other ancillary equipment such as existing controlled-gas delivery, and potentially pressure, applied field set-ups, etc.
        Examples of the spectrometer capabilities are shown through select case studies.

        Speaker: Nicolas de Souza (ANSTO - Australian Centre for Neutron Scattering)
      • 18:01
        Elemental imaging of iron-bioengineered wheat grain using synchrotron X-ray fluorescence microscopy. 1m

        Over the past decades, efforts have been made to increase the nutrition value of staple food crops including wheat grain. Recently, we were able to produce a metabolic engineered wheat variety capable to increase the accumulation of iron (Fe) in grain (Beasley et al., 2019). In order to determine the distribution of elevated Fe levels and other elements in this grain, we performed elemental imaging studies at the Australian Synchrotron X-ray fluorescence microscopy (XFM) beamline. XFM imaging was conducted on transverse cross-sections of representative mature grains from two null segregant (NS) and two genetically modified (GM) wheat (Triticum aestivum) using two synchrotron-based XFM imaging systems: a 384 Maia detector and a Vortex-EM detector. Grain samples (80 µm in thickness) were analysed in continuous mode in the horizontal direction by a sampling interval of 4 µm and a step size of 4 µm in the vertical direction with a transit analysis time of 5.2 ms. The XRF signal was used to generate the elemental maps of Fe, zinc (Zn), copper (Cu), manganese (Mn) and phosphorous (P). Elemental maps were generated and analysed using GeoPIXE software. The results indicated a difference in Fe distribution between NS and GM grains. The increase of Fe accumulation in GM grain occurred in the endosperm, crease and aleurone regions relative to NS grain. The results provide a unique insight into the mechanisms of Fe distribution in iron-bioengineered wheat grain and highlights the significance of using synchrotron-based XFM imaging in the study of metal distribution in plants.

        Beasley, J.T., Bonneau, J.P., Sanchez-Palacios, J.T., Moreno-Moyano, L.T., Callahan, D.L., Tako, E., Glahn, R.P., Lombi, E. and Johnson, A.A.T. (2019) Metabolic engineering of bread wheat improves grain iron concentration and bioav;ailability. Plant Biotechnol. J., https://doi.org/10.1111/pbi.13074

        Speakers: Dr Jose Tonatiuh Sanchez-Palacios (Institute for Applied Ecology, University of Canberra), Prof. Lombi Enzo (Future Industries Institute, University of South Australia)
      • 18:02
        A solid-state microdosimeter for dose and radiation quality monitoring for astronauts in space 1m

        Space exploration is currently aiming to reach further destinations, increasing astronauts’ exposure to hazardous radiation. Although at the altitude of the International Space Station, the main radiation source is protons, heavy ions (e.g. C, O, Si, Fe) cover a wide energy range up to hundreds of GeV/n. Their high LET makes them strong contributors for radiobiological effects on humans, also because the incur in fragmentation.
        Microdosimetry is a powerful approach for evaluating the quality factor Q of a mixed radiation field typical of space radiation, without knowing the energy or type of particles.
        The Centre for Medical Radiation Physics, University of Wollongong in collaboration with SINTEF, and ANSTO, has been active in the development of SOI microdosimeters, for radiation protection purposes. Compared to conventional TEPCs, SOI microdosimeters are portable, don't require a high voltage power and have an easy readout system. SOI consist of a matrix of 400 silicon sensitive volumes (SVs) with dimensions comparable to cell nucleus.
        In this abstract, we present results obtained at the Heavy Ions Medical Accelerator in Chiba (HIMAC), Japan, where the novel SOI “Mushroom” was tested with Oxygen, Neon, Silicon and Iron ions, in a energy range of 400÷500MeV/u.

        The “Mushroom” was preliminary tested using the ion beam induced charge collection technique with 5.5 MeV He2+ at ANSTO. Results confirm excellent SV definition and uniform charge collection without cross talk between the adjacent SVs.
        At HIMAC, we studied the spacecraft’s wall effect for shielding energetic heavy ions, in terms of Q and dose equivalent Hp(10). A realistic multi-layers sample of spacecraft wall was reproduced and placed in front of the detector. Different wall's configurations were used to study the shielding effect of each layer. Secondly, we measure the Hp and Q at different depths in a water phantom, mimicking different positions in the human body.

        An example of results obtained from irradiations carried out with 500MeV/u Fe56 ions shows that the microdosimetric spectra when we considered only aluminium layers of the wall is broader due to the presence of fragments produced by primary beam interacting with the wall, compared to the sharp peak of primary particles when no wall is used. Because of the change of the radiation field’s composition, the value of Q changes as well.
        Results from the water phantom irradiation show how Q and Hp varies deeper in an astronaut’s body. When the wall is considered (scenario of an astronaut inside the spacecraft), the Bragg Peak shifted at a shallower depth in the body causing an exposure to different organs, followed by higher Q values.

        To conclude, for wide energy ranges of GCR ions, the wall does not always reduce the radiation hazard inside the spacecraft, but can produce secondary particles. Particularly, the Q and Hp can increase at shallow depth in the body of an astronaut. This study confirms that the portable SOI “Mushroom” microdosimeter is suitable for qualifying the radiation field in space and evaluating the efficiency of shielding materials, in terms of Q and H.

        Speaker: Ms Stefania Peracchi (University of Wollongong)
      • 18:03
        KOALA - A single-crystal neutron diffractometer 1m

        A postre setting out the parameters around the KOALA instrument will be displayed. The instrument scientists will be available to discuss any aspects of the instrument or the science it can be applied to .

        Speaker: Alison Edwards (ACNS, ANSTO)
      • 18:04
        Using light to remote control metal-coordination 1m

        The ability to precisely control molecules with external stimuli is an important tool for various chemical systems such as catalysts, bio-active probes and host-guest systems. 1, An attractive approach to preparing materials that can be systematically controlled is the integration of tuneable “switches” into compounds, thus allowing the reversible conversion between two or more stable states. Various functions that can be regulated by stimuli-responsive switches include intramolecular energy transfer processes and valencetautomerism involving changes to magnetic properties. 2, External stimuli typically used in such materials include electrical and magnetic fields, 2 thermal treatment, 3 solvent composition changes, chemical addition and light exposure. 4 Despite the rich optical, magnetic and redox properties available to metal complexes, switchable systems that result in changes in the coordination environment of metal ions remain rare. Switchable complexes of this nature could act as efficient 'smart metal complexes’ if the properties of the metal ion could be controlled using easily applied and highly selective external stimuli. Light is a particularly attractive stimulus for switching materials due to its non-intrusive and cost-effective nature. Optimisation and control of the switching function of photoactive metal complexes will require a comprehensive understanding of structure on the molecular scale, which can be efficiently achieved with the rapidly developing technique of photocrystallography – that is, the determination of a single crystal X-ray structure while simultaneously photo-irradiating the sample. 5

        The aim of this work is to design, synthesise and characterise organometallic systems which incorporate a photochromic moiety where the coordination geometry of the metal-centre can be systematically regulated with light. To understand how these molecules function and the structural changes that occur upon photo-irradiation, precise atomic-scale information will be required for the materials both before and after switching. The MX1 and MX2 beamlines of the Australian Synchrotron will use to obtain this information.

        References

        1. Raymo, F. M.; Tomasulo, M. Chem. Soc. Rev. 2005, 34 (4), 327-336.
        2. Hoque, J.; Sangaj, N.; Varghese, S. Macromolecular Bioscience 2019, 19 (1), 1800259.
        3. Sato, O.; Tao, J.; Zhang, Y.-Z. Angew. Chem. Int. Ed. 2007, 46 (13), 2152-2187.
        4. Berryman, O. B.; Sather, A. C.; Lledó, A.; Rebek Jr., J. Angew. Chem. Int. Ed. 2011, 50 (40), 9400-9403.
        5. P. Coppens, Struct. Dyn.,2017, 4, 032102 , Coppens, P. and Fournier, B., J. Synchrotron Radiat., 2015, 22, 280– 287
        Speaker: Kasun Athukorala Arachchige (Uq postdoctoral fellow)
      • 18:05
        Kookaburra, the ultra-small-angle neutron scattering instrument at ANSTO: design and recent applications 1m

        The double-crystal ultra-small-angle neutron scattering (USANS) diffractometer KOOKABURRA at ANSTO was made available for user experiments in 2014. KOOKABURRA allows the characterization of microstructures covering length scales in the range of 0.1–10 µm. Use of the first- and second-order reflections coming off a doubly curved highly oriented mosaic pyrolytic graphite pre-monochromator at a fixed Bragg angle, in conjunction with two interchangeable pairs of Si(111) and Si(311) quintuple-reflection channel-cut crystals, permits operation of the instrument at two individual wavelengths, 4.74 and 2.37 Å (see more at https://www.ansto.gov.au/user-access/instruments/neutron-scattering-instruments/kookaburra-ultra-small-angle-neutron). This unique feature among reactor-based USANS instruments allows optimal accommodation of a broad range of samples, both weakly and strongly scattering, in one sample setup [1,2]. The versatility and capabilities of KOOKABURRA have already resulted in a number of research papers, including studies on hard matter systems like rocks and coal [3,4], as well as soft matter systems like hydrogels or milk [5,6]. This clearly demonstrates that this instrument has a major impact in the field of large-scale structure determination. Some of the recent examples will be presented here.

        References
        [1] Rehm, C. et al, J. Appl. Cryst., 2013, 46 1699-1704.
        [2] Rehm, C. et al, J. Appl. Cryst., 2018, 51, 1-8.
        [3] Blach, T. et al, Journal of Coal Geology, 2018, 186, 135-144.
        [4] Sakurovs, R.et al, Energy & Fuels, 2017, 31(1), 231-238.
        [5] Whittaker, J. et al, Int. J. Biol. Macromol., 2018, 114, 998-1007.
        [6] Li, Z. et al, Food Hydrocolloid, 2018, 79, 170-178.

        Speaker: Jitendra Mata (ANSTO)
      • 18:06
        Effect of solution conditions on the recovery of uranyl ions using a metal-binding protein on silica nanoparticles 1m

        Many methodologies have been developed to separate metal ions from water for the purpose of mining or decontamination. Most of these approaches are based on amidoxime-based polymers, hydrogels, microspheres, fibres and metal-organic frameworks [1-3]. However, such approaches are typically inefficient with low selectivity. Recently Zhou et al. [4] have reported a super uranyl binding protein (SUP) with a femtomolar affinity and a high selectivity for uranyl. Following this exciting result, SUP has been combined with different recyclable systems for the separation of uranyl ions from seawater and other sources [1, 3, 5]. Nevertheless, most of them still rely on the polymer or hydrogel-based systems which are either expensive or need complicated devices for uranyl capture. Thus, there is an unmet need to develop an efficient and yet simple system to use SUP for recovery of uranyl.

        It is attractive to use low-cost matrix such as silica particles for recycling SUP. However, such matrix systems often require chemical modifications of surface; it does not only increase the cost but also decrease protein activities. In this work, we utilized a simple method to immobilize SUP on silica particles without chemical functionalization of silica surface. The binding of SUP on silica is facilitated by a high affinity silica binding peptide. In order to achieve optimal immobilization, we have included a peptide linker that connects SUP with silica binding peptide (CotB[6]). The engineered bi-functional proteins enable silica surface and uranyl ion binding at the same time. These proteins have been successfully expressed and purified, and their performance have been evaluated by determining their silica and uranyl binding abilities as well as their stability, and oligomeric state by multiple techniques that range from colorimetric assays to small angle scattering using different concentrations of sodium chloride. Results suggest that sodium chloride plays an important role for the optimal binding of uranyl ions by SUP.

        References:
        1. Kou, S., Z. Yang, and F. Sun, Protein hydrogel microbeads for selective uranium mining from seawater. ACS Applied Materials and Interfaces, 2017. 9(3): p. 2035-2039.
        2. Liu, C., et al., A half-wave rectified alternating current electrochemical method for uranium extraction from seawater. Nature Energy, 2017. 2(4).
        3. Zhang, X.J., et al., A Versatile and Robust Approach to Stimuli-Responsive Protein Multilayers with Biologically Enabled Unique Functions. Biomacromolecules, 2018. 19(3): p. 1065-1073.
        4. Zhou, L., et al., A protein engineered to bind uranyl selectively and with femtomolar affinity. Nature Chemistry, 2014. 6(3): p. 236-241.
        5. Kou, S., et al., Entirely recombinant protein-based hydrogels for selective heavy metal sequestration. Polymer Chemistry, 2017. 8(39): p. 6158-6164.
        6. Abdelhamid, M.A.A., et al., Affinity purification of recombinant proteins using a novel silica-binding peptide as a fusion tag. Applied Microbiology and Biotechnology, 2014. 98(12): p. 5677-5684.

        Speaker: Gina Pacheco (Monash University)
      • 18:07
        Porosity evolution in nickel-iron sulphide minerals during hydrothermal reactions 1m

        Mineral porosity contributes to rock permeability and hence influences the movement of hydrothermal fluids in the crust and the formation of mineral deposits. Porosity is an important factor for in-situ recovery of base metals from ore deposit without traditional mining. Mineral porosity can be generated during fluid-mineral reactions yet the evolution of such reaction-induced porosity is still poorly understood. In this work, we studied porosity evolution during the hydrothermal mineral replacement of nonporous pentlandite ((Fe,Ni)9S8) by porous violarite ((Fe,Ni)2S4), the important reaction responsible for the alteration of pentlandite in natural supergene environments. Using ultra small angle neutron scattering (USANS) [1] and small angle neutron scattering (SANS) [2], we obtained total porosity, pore size distribution, and open-total pore ratio data before and after complete replacement. The majority of these reaction-induced pores are open pores, while the pores below ~10 nm in diameter are mainly closed pores. The evolution of pores in violarite is significant during the replacement process but very slow after the complete replacement. This quantitative examination of reaction-induced porosity in violarite has increased our understanding of porosity evolution and how it contributes to the mineralisation in and around nickel deposits. In addition, it has increased our understanding of the reactivity, during hydrometallurgical processing, of nickel iron sulphide minerals.

        [1] C. Rehm, L.d. Campo, A. Brûlé, F. Darmann, F. Bartsch, A. Berry, Design and performance of the variable-wavelength Bonse–Hart ultra-small-angle neutron scattering diffractometer KOOKABURRA at ANSTO, Journal of Applied Crystallography, 51 (2018) 1-8.
        [2] A. Sokolova, A.E. Whitten, L. de Campo, J. Christoforidis, A. Eltobaji, J. Barnes, F. Darmann, A. Berry, Performance and characteristics of the BILBY time-of-flight small-angle neutron scattering instrument, Journal of Applied Crystallography, 52 (2019).

        Speaker: Muhammet Kartal (Murdoch University)
      • 18:08
        Small-angle X-ray scattering as a quantitative screening tool: initial benchmarks across synchrotron beamlines 1m

        The process of ligand recognition can significantly alter the physical morphology of macromolecules, as a part of their in-vivo function. These changes can be quantified via solution small-angle X-ray scattering (SAXS), a technique that provides structural information as a distribution of distances between all solute atoms. Measurements can be sufficiently precise to detect small yet global conformational changes. In the context of drug discovery, this not only enables differentiation between agonists and antagonists, but also to derive effective binding affinities by extracting the population of bound and unbound receptors from the mixed scattering intensities. However, the current lack of extensive screening benchmarks render it difficult to predict how informative this technique will be for an arbitrary system.

        To help push things forward, we selected the 26 kDa bacterial periplasmic protein HisBP as an initial benchmark, and titrated its interactions with four ligands with KD values spanning 40 nM ~ 200 μM at multiple synchrotron beam-lines. These small-scale screening trials are found to be reproducible and transferable across the 96-well plate automated setups available on-site. Our current titration protocols allow structural differentiation between the native histidine-bound versus decoy arginine-bound HisBP, and quantitative KD predictions at receptor concentrations as low as 0.5 mg/ml (20 μM). The practical KD sensitivity range is bounded by receptor concentration and total measurement time, which translates into effective limits on expected throughput within available beamtime. We hope to encourage broader testing so as to eventually establish a general protocol for SAXS-based screening.

        Speaker: Dr Po-chia Chen (EMBL Heidelberg)
      • 18:09
        Recent and future upgrades to the Kowari instrument 1m

        This poster will highlight some of the recent upgrades to the Kowari detector shroud and detail potential future upgrades to increase the accuracy and speed of sample positioning on the instrument.

        Speaker: Dr Mark Reid (ANSTO)
      • 18:10
        Microbial factories to complement chemical synthesis of deuterated molecules. 1m

        Deuterated cholesterol is a classic example of nature providing an elegant alternative to chemical synthesis. The humble yeast used in bread and beer making has been engineered to produce pure cholesterol, which can be deuterated to varying degrees by growth on the appropriate substrates. This complements our existing capability to synthesise a specific tail-deuterated form of cholesterol for use in membrane structure and behaviour research.
        The expanding range of molecules available from the National Deuteration Facility provide the contrast required for neutron, IR and NMR characterisation of complex systems. Microbial cellulose has been studied in conjunction with ionic liquids, both of which can be produced in deuterated form.
        Complementing or utilising synthetically deuterated molecules, yeast and algae are recent additions to our toolbox for producing deuterated fatty acids, sterols, polysaccharides and other biopolymers.

        Speaker: Rob Russell (ANSTO)
      • 18:11
        Charge Density Studies of Photo-redox Metal Complexes: An Experimental Comparison of the Ground and Lowest Excited States. 1m

        The photo-induced transfer of electrons (PET) forms the basis for biological and environmental processes fundamental to life, including photosynthesis and atmospheric ozone generation.[1] It also underpins a range of vital technologies[2] such as photocatalysis,[3] which has key applications in environmentally sustainable chemical manufacturing, and a global market expected to reach AU $ 6.64 billion by 2025.[4] A thorough understanding of PET and the species involved will be of great benefit to the Australian chemicals industry.

        Owing to their rich physical and chemical properties, metal complexes are widely applicable for PET processes, and accordingly account for the vast majority of available photocatalysts. As their functions arise through their ability to accept or donate electrons upon absorption of light, knowledge of the distribution of electronic charge over their structures in both the ground and in excited states is critical for understanding their behaviour.

        While significant theoretical efforts have been made to model their electronic structures,[5] experimental data is rare. The collection of experimental data that reveals the distribution of electronic charge on photo-redox metal complexes is of paramount importance for the development of a more complete understanding of their PET behaviour.

        Charge-density X-ray experiments combined with in situ photo-excitation provide a method of obtaining this experimental data in both ground and excited states. High-quality single crystal neutron diffraction studies, such as those possible using the KOALA beamline at the Australian Centre for Neutron Scattering, are required for these measurements to establish the nuclear coordinates, particularly the position of hydrogen atoms.

        Our current interest in this research is focused on elucidating the charge density structures of well-known photocatalysts such as tris-2,2'-bipyridineruthenium(II) ([Ru(bpy)3]2+)[6] and tris[2-phenylpyridinato-C2,N]iridium(III) ([Ir(ppy)3]).[5a] Experiment design and preliminary data in this avenue of research will be presented.

        1. B. Eliasson, M. Hirth, et al., J. Phys. D: Appl. Phys., 1987, 20, 1421-1437.
        2. (a)T. D. Ashton, K. A. Jolliffe, et al., Chem. Soc. Rev., 2015, 44, 4547-4595; (b)A. Listorti, B. O’Regan, et al., Chem. Mater., 2011, 23, 3381-3399; (c)A. Periasamy, Fluorescence resonance energy transfer microscopy: a mini review, SPIE, 2001.
        3. K. L. Skubi, T. R. Blum, et al., Chem. Rev., 2016, 116, 10035-10074.
        4. Grand View Research, 2017.
        5. (a)B. J. Powell, Coord. Chem. Rev., 2015, 295, 46-79; (b)I. N. Mills, J. A. Porras, S. Bernhard, Acc. Chem. Res., 2018, 51(2), 352-364.
        6. (a)P. S. Braterman, A. Harriman, G. A. Heath and L. J. Yellowlees, J. Chem. Soc., Dalton Trans., 1983, 1801-1803; (b)G. A. Heath, L. J. Yellowlees and P. S. Braterman, J. Chem. Soc., Chem. Commun., 1981, 287-289
        Speaker: Michael Pfrunder (University of Queensland)
      • 18:12
        The BILBY small-angle neutron scattering instrument 1m

        BILBY [1] is a time-of-flight (ToF) small-angle neutron scattering (SANS) instrument operated by the Australian Centre for Neutron Scattering (ACNS) at the Australian Nuclear Science and Technology Organsation (ANSTO). It entered the user program in 2016 and complements the established SANS capability at the ACNS - the monochromatic pin-hole SANS instrument QUOKKA [2] and the USANS instrument KOOKABURRA [3].

        Utilising an array of position sensitive detectors and ToF, BILBY can measure a large q-range in a single measurement (~0.001 - 1.8Å-1). This characteristic makes BILBY well suited to the study of materials over time. Additionally, the choppers can be used to tune the wavelength resolution (Δλ/λ) to values between approximately 3 - 30%. The high wavelength resolutions are well suited to the study of liquid crystals, while the lower wavelength resolutions are well suited to measurements where neutron flux is important, such as a kinetic experiments.

        Over 30 peer reviewed articles that have utilised the BILBY SANS instrument are now published. Here, we will present details regarding the instrument, together with some scientific highlights from the first few years of operation

        [1] A. Sokolova et al, J. Appl. Crystallogr. 52, 1-12 (2019)
        [2] K.Wood et al, J. Appl. Crystallogr. 51, 294-341 (2018)
        [3] C. Rehm et al, J. Appl. Crystallogr. 51, 1-8 (2018)

        Speaker: Dr Andrew Whitten (Australian Nuclear Science and Technology Organisation)
      • 18:13
        In situ synchrotron PXRD study of the replacement of bornite under anoxic conditions 1m

        Bornite (Cu5FeS4) is the second most abundant Cu-bearing ore mineral, and is found in a wide range of ore deposits. It is often altered in hydrothermal fluids by mineral replacement reactions, forming complex intergrowth textures with chalcopyrite (CuFeS2), digenite (Cu1.8S), covellite (CuS), and chalcocite (Cu2S). Yet, the mechanism and kinetics of the chemical reactions responsible for the alteration of bornite are still poorly understood. In this work, the hydrothermal mineral replacement of bornite was monitored by synchrotron-based in situ powder X-ray diffraction (PXRD) under anoxic conditions, at the powder diffraction beamline at the Australian Synchrotron. By collecting time-resolved PXRD patterns during the reactions, direct information about the phase evolution was obtained and the fate of transient reaction intermediates was observed. This presentation reports the effects of temperature, solution chemistry, and reaction time on the mechanism and kinetics of bornite alteration. The results suggest that the reaction is faster in chloride-rich fluids, and is generally promoted by increasing temperature and time. The outcomes of this study provide some insights into the mineralization in and around copper deposits.

        Speaker: Mr Idowu Abiodun Adegoke (Murdoch University)
      • 18:14
        SOI Thin Microdosimeter Detectors for Low Energy Ions and Radiation Damage Studies 1m

        The aim of this work was to study the applicability of silicon microdosimeters for high LET ion measurements. The response and radiation damage of two silicon on insulator (SOI) 3D microdosimeters developed by the Centre for Medical Radiation Physics (CMRP) were investigated with a range of different low energy ions, with high linear energy transfer (LET). The two microdosimeters n-SOI and p-SOI were irradiated with a number of different ions including $^{7}$Li, $^{12}$C, $^{16}$O and $^{48}$Ti with ranges below 350 µm in silicon.

        The two detectors used in this work are called the Bridge and the Mushroom. The Bridge microdosimeter is based on an array of planar 30 x 30 x 10 µm cubic SVs fabricated on a high resistivity of 3 kΩ.cm n-SOI active layer of thickness 10 µm and low resistivity supporting wafer [1]. The Mushroom microdosimeter structure used in this work is called a trenched 3D and it consists of 3D cylindrical SVs with a core columnar n+ region and each SV is surrounded with p+ trench to form a p-n junction. The Mushroom microdosimeter has a thickness of 9.1 um and diameter of 30 µm fabricated on high resistivity p-type silicon (> 10 kΩ.cm).

        Using a specially generated low intensity beam (beam fluence of approximately 1200 particles/s), irradiations were conducted at The Heavy Ion Accelerator Facility (HIAF) at the Australian National University using both the Bridge and Mushroom 3D microdosimeters. Radiation damage of the Bridge and Mushroom microdosimeters was studied using the ion beam induced charge collection technique (IBIC) at the 6 MV accelerator SIRIUS, located at the Centre for Accelerator Science (CAS) facility at ANSTO. This system includes a Confocal Heavy Ion Micro-Probe (CHIMP) which is capable of delivering Carbon, Helium and Hydrogen ions with energies of 24 MeV, 5.5 MeV and 8 MeV, respectively.

        Results presented will show that no plasma effects were seen in the SOI microdosimeters when irradiated with the high LET ions. A Monte Carlo simulation using Geant4 was compared to the experimental measurements, whereby some discrepancies were observed for heavier ions at lower energies. This discrepancy can be partly attributed to uncertainties in the thickness of the energy degraders and overlayers of the devices. The radiation hardness of the two devices was studied using the Ion Beam Induced Charge Collection technique (IBIC). Charge buildup was seen outside of the SV in the SiO$_2$ layer after irradiation, however both types of microdosimeters when biased had no essential changes in charge collection efficiency (CCE) in the SV after irradiation with low energy ions. IBIC results for both detector types will be presented in full

        References:
        [1] L. T. Tran, L. Chartier, D. Bolst, et al., “3D silicon microdosimetry and rbe study using $^{12}$C ion of different energies,” IEEE Trans Nucl Sci, vol. 62, no. 6, pp. 3027–3033, Dec 2015.

        Speaker: Benjamin James (UOW - CMRP)
      • 18:15
        Characterisation of Rhodium and Iridium Hybrid Catalysts by X-ray Absorption Spectroscopy 1m

        Transition-metal catalysis is ubiquitous in synthetic chemistry and among the most important processes in the chemical industry. Surface immobilised transition metal catalysts, known as hybrid catalysts, combine the efficiency of heterogeneous- and the selectivity of homogenous catalysts. Advantages of hybrid catalysts over traditional homogeneous analogues are stability and simplified removal of the catalyst from the reaction mixture, which provides access to urgently needed more efficient and greener processes.$^1$ Here, we present a series of new hybrid rhodium- and iridium based pyrazole-triazole (PyT) complexes attached to carbon black (CB) with varying tether lengths. The synthesis of the long alkyl chain ligands was accomplished through tin mediated acylation of aromatic systems$^2$ and Click-chemistry, giving the PyT-group. This was followed by metal coordination, affording the Rh- and Ir-complexes. The catalysts are anchored to the surface via a phenyl group, which is connected to an alkyl linker of varying lengths bearing the catalytically active metal complex as head group. We immobilised the catalysts on CB using radical methodology. Initially, we optimised grafting conditions to gain control over the metal loading on the surface. Furthermore, we attached both rhodium- and iridium catalysts simultaneously to obtain heterobimetallic mixed layers.$^3$ The developed hybrid catalysts were analysed using a number of techniques, including SEM/EDX, XPS.
        The hybrid catalysts were all found to be efficient catalysts that were robust and recyclable. In particular, they promote the hydrosilylation of phenylacetylene, generating a mixture of the $\beta$(E),-$\beta$(Z) and $\alpha$ and isomers of the respective silylated alkenes. Interestingly, the homogeneous Rh complexes give a mixture of all isomers, while the same Rh complexes immobilised on CB are selective for the $\alpha$-isomer. In contrast, both the homogeneous and hybrid Ir complexes give the $\beta$(Z)-isomer. XAS measurements were performed at the Australian Synchrotron to probe possible surface effects influencing the catalytic activity of the hybrid catalysts. We recorded EXAFS spectra of the monometallic and heterobimetallic hybrid complexes at the Rh K- and Ir L3-edges, respectively, providing an additional tool for probing surface effects in catalysis.

        References

        1. Wong, C. M.; Walker, D. B.; Soeriyadi, A. H.; Gooding, J. J.; Messerle, B. A. Chem. Sci. 2016, 7 (3), 1996-2004.
        2. Chen, X.; Roemer, M.; Yuan, L.; Du, W.; Thompson, D.; del Barco, E.; Nijhuis, C. A. Nat. Nanotechnol. 2017, 12 (8), 797-803.
        3. Binding, S. C.; Pernik, I.; Gonçales, V. R.; Wong, C. M.; Webster, R. F.; Cheong, S.; Tilley, R. D.; Garcia-Bennett, A. E.; Gooding, J. J.; Messerle, B. A. Organometallics 2019, 38 (4), 780-787.
        Speaker: Max Roemer (Macquarie University)
      • 18:16
        Recent Progress on the Toroidal ARPES Detector at the Australian Synchrotron 1m

        Angle Resolved Photoelectron Spectroscopy (ARPES) is the “complete” photoemission experiment. It simultaneously measures a photoelectron’s kinetic energy, emission angle and sometimes spin, relative to the crystallographic axes, constructing a direct image of the electronic bandstructure. This makes ARPES the most powerful contemporary technique for determining the electronic structure of novel materials. ARPES has been instrumental in the discovery and understanding of new electronic phases of matter. For example, important aspects of the electronic structure of high-Tc superconductors, such as the pseudogap were discovered using ARPES, as was the experimental discovery of three dimensional topological insulators Bi1-xSbx and Bi2(Se,Te)3. Over the years, a dramatic improvement in the energy and momentum resolution possible with ARPES has occurred as a result of advances in photoelectron analysers and 2D detectors, allowing a range of new physics to be probed.

        Despite the popularity of ARPES overseas, within Australia it has until now remained as a niche technique due to a small (albeit dedicated) user community. However, the continually growing local interest in studying novel materials with exotic electronic properties has led to the demand for our own synchrotron – based ARPES instrument. The ARPES detector, a toroidal geometry analyser, is now installed at the Soft X-ray beamline with commissioning completed and first experiments conducted. An overview of the latest developmens on the instrument is presented. A substantial upgrade to the system's capabilities has been comppleted via the recent installation of (i) an intense microwave-based, monochromated, helium discharge VUV source and (ii) a scanning tunnelling microscope (Fermi SPM, Scienta Omicron GmbH).

        Speaker: Anton Tadich
      • 18:17
        Quantification of thermal neutron fluence in high-energy LINAC radiotherapy for quality assurance dose enhancement 1m

        Radiotherapy based treatment involving a linear accelerator (LINAC) is one of the most widely used treatment modalities for cancer patients. LINACs utilize a high energy photon beam to penetrate the body and deliver a pre-determined dose to the tumour. However when LINAC energies greater than 10MV are used during treatment, photo neutrons are produced through nuclear interactions within the LINAC and its components. These neutrons are capable of delivering large amounts of damage through indirect methods to undesirable regions of the body. This effect increases the risk for induction of a secondary cancer due to unwanted exposure.

        While photo neutrons produced by a LINAC are inevitable, their high damaging capabilities are of high interest. An investigation is carried out within this study towards determining whether Boron Neutron Capture Therapy (BNCT) techniques can be implemented in addition to a radiotherapy treatment. This technique can aid in administering additional dose to a tumour thus increasing the probability of a successful treatment. This work presents a new direction towards experiments evaluating the possible damage that can be caused due to BNCT during a radiotherapy treatment.

        This study examines the effectiveness of a silicon on insulator (SOI) microdosimeter developed by the Centre of Medical and Radiation Physics (CMRP) known as the Bridge, in determining microdosimetric quantities such as the dose equivalent (H) and relative biological effectiveness (RBE) in a mixed photon-neutron radiation field. Cell uptake of a {10}^B compound is modelled through the use of a {10}^B_{4}C thin film converter. The radiobiological properties neutrons possess outside the treatment field are determined in this work. Implementing microdosimetric techniques, it was found that for a distance of 50cm from isocenter, the dose equivalent is approximately 0.14mSv/photon-Gy with an RBE10 value of 1.6 for cells with a modelled {10}^B uptake. For a patient undergoing a head and neck treatment procedure, this can correspond to an integral dose of 9.8mSv to just the abdominal region during a 70Gy radiotherapy treatment.

        This work also explores a newly developed SOI device designed by CMRP that will further aid in investigating the effect BNC techniques may have within the body. The “mushroom” microdosimeter is a 3D device with free standing sensitive volumes (SVs) called “mushrooms”. Utilizing 3D micro-electro-mechanical systems (MEMS) technology at SINTEF, Norway, as well as deep reactive ion etching (DRIE), these 3D sensitive volumes possess outstanding energy resolution. Each SV is 2µm in thickness allowing for an accurate determination of the lineal energy in a mixed radiation field, such as the one present in a high energy LINAC. These devices have been characterized in terms of their charge collection efficiency (CCE) utilizing an ion beam induced charge (IBIC) collection technique with 1.78MeV and 5.5MeV He^{2+} ions at the 6MV SIRIUS accelerator located at ANSTO. The reduced SV thickness of the mushroom microdosimeter when compared to the 10µm thick Bridge microdosimeter used in this work, will aid in addressing some of the issues that arose during this study.

        Speaker: Vladimir Pan (University of Wollongong)
      • 18:18
        The capabilities of the cold-neutron triple-axis spectrometer SIKA at ANSTO 1m

        SIKA, the new cold-neutron triple-axis spectrometer was built on the CG4 beam port at the OPAL reactor, ANSTO. We report the capabilities and current status of SIKA in this users meeting. A versatile instrument, SIKA provides sample environments with temperature capacities from dilution temperatures below 50 mK up to 750 K, and magnetic fields of up to 12 T, using the well-developed control and analysis software based on SPICE. Several scientific examples demonstrating the proficiency of SIKA are reported such as;observation of higher harmonics of the helical magnetic phase of MnP as an example of elastic magneticscattering; measurement of the phonon-dispersion in Al with the estimated slope of the transverse acoustic phonon at 32.4meV; the spin-wave dispersion in MnF$_2$ along the c-axis enabling determination of exchange parameters J$_1$ = 0.0305 meV, J$_2$ = -0.1534meV and, D = 0.1427 meV; and observation of one of the crystal field excitations from Pr$^{3+}$ in PrFeO$^3$ powder. These results can help you to estimate beam time of experiments for your proposals.
        Finally, we discuss recent development of SIKA. A $^{3}$He polarization analysis system will be ready for SIKA to perform polarized neutron scattering experiments in 2020. SIKA will also be able to accommodate a RITA-type multiple-analyzer system to perform experiments more efficiently by 2020.

        Speaker: Shinichiro Yano (NSRRC)
      • 18:19
        Wombat – the high intensity diffractometer at OPAL 1m

        Wombat is a high intensity neutron diffractometer located in the OPAL Neutron Guide Hall. It is primarily used as a high-speed powder diffractometer, but has also expanded into texture characterisation and single-crystal measurement, particularly diffuse scattering. The high performance comes from the combination of the best area detector ever constructed for neutron diffraction with the largest beam guide yet put into any research reactor and a correspondingly large crystal monochromator, all combine with the centre’s polarisation capability to provide an instrument which is unique within the Southern hemisphere.

        Wombat has been used to explore a broad range of materials, including: novel hydrogen-storage materials, negative-thermal-expansion materials, methane-ice clathrates, piezoelectrics, high performance battery anodes and cathodes, high strength alloys, multiferroics, superconductors and novel magnetic materials. Our poster will highlight both the capacity of the instrument, and some recent results.

        Speaker: Helen Maynard-Casely (Australian Nuclear Science and Technology Organisation)
      • 18:20
        Crystallisation of Lipids at the Oil/Water Interface 1m

        Crystallisation of lipids at the oil/water interface plays a significant role in the stability of emulsion systems [1, 2]. This is regardless of whether the emulsion is composed of lipids in the continuous or dispersed phase. Interfacial crystallisation is of particular interest for dairy products, as emulsified lipids undergo crystallisation upon cooling during production and storage. Lipid crystals also play an important role in the structure and texture of dairy products. Despite the influence of crystals at the oil/water interface on emulsions systems, factors influencing crystal interfacial activity are not well understood.

        The work to be presented has the aim of understanding the effect of thermal cycling, ionic strength, and the type of surface active molecules on interfacial activity and structure of lipid crystals at the oil/water interface. The oil and aqueous phases were chosen in order to mimic a model dairy system. Profile analysis tensiometry (PAT) has been used, as the technique allows for the monitoring of the kinetics of interfacial tension in response to temperature changes. The temperature at which interfacially active lipid crystals are formed has been determined from those experiments. It can be concluded that both the addition of surfactant and the surfactant type alter the interfacial tension profiles for heating and cooling cycles compared to the pure system. Synchrotron small angle X-ray scattering was conducted on emulsion systems to study the formation, growth and structure of lipid crystals, following a temperature cycling regime similar to that conducted with PAT.

        References
        1. Douaire, M., et al., Fat crystallisation at oil–water interfaces. Advances in colloid and interface science, 2014. 203: p. 1-10.
        2. Rousseau, D., Fat crystals and emulsion stability—a review. Food Research International, 2000. 33(1): p. 3-14.

        Speaker: Ms Stephanie V. MacWilliams (University of South Australia)
      • 18:21
        Trace element speciation and incorporation in iron oxides within mineral processing residues 1m

        Iron oxides make up a large proportion of mineral processing residues and play an important role in hosting trace elements through either surface adsorption or isomorphous substitution. Mineral processing residues can contain elevated concentrations of trace metals such as As, Cr, Mo, V and Zn, most likely associated with iron oxides, and which pose challenges to successful remediation. Therefore, understanding the fundamental mechanisms of incorporation of these trace metals within iron oxides is of importance for understanding their speciation and mobility in residues throughout the remediation process. The present study investigated the incorporation of single and multiple metals (Al, As, Cr, Mo, V and Zn) into synthetic goethites and hematites. Element concentrations were quantified by a mixed acid digest followed by Inductively Coupled Plasma Optical Emission Spectroscopy. Structures were characterised by synchrotron X-ray diffraction, and changes in unit-cell dimensions upon substitution of trace metals were quantified using the Rietveld method in TOPAS. The speciation of redox-sensitive substituents was characterised by X-ray Absorption Near Edge Spectroscopy. Preferential incorporation of trace elements was observed, and the incorporation of metals was shown to alter unit cell dimensions of the synthetic iron oxides. The presence of metals also influenced crystal morphology, surface properties and chemical stability of the iron oxides. Results from this work are expected to provide insights into the structure, behaviour, and properties of iron oxides within mineral processing residues and the broader environment.

        Speaker: Grace Scullett-Dean (University of Western Australia)
      • 18:22
        QUOKKA, THE PINHOLE SMALL-ANGLE NEUTRON SCATTERING INSTRUMENT AT THE OPAL RESEARCH REACTOR, AUSTRALIA: DESIGN, PERFORMANCE AND OPERATION. 1m

        QUOKKA was the first SANS instrument to be in operation at the Australian research reactor, OPAL [1]. It is a 40 m pinhole instrument operating with a neutron velocity selector, an adjustable collimation system providing source-sample distances of up to 20 m and a two dimensional 1 m2 position-sensitive detector, capable of measuring neutrons scattered from the sample over a secondary flight path of up to 20 m. Also offering incident beam polarization and analysis capability as well as lens focusing optics, QUOKKA has been designed as a general purpose SANS instrument with a large sample area, capable of accommodating a variety of sample environments. Some of these sample environments are, a Rapid Heat Quench Cell enabling a sample to be studied in situ following a thermal shock (-120°C to 220°C); The neutron Rapid Visco Analyser (nRVA) which enables SANS to be measured simultaneously with viscosity via an RVA – an instrument widely used within the food industry; In-situ Differential Scanning Calorimetry (DSC); A stopped flow cell, and RheoSANS.
        Here we describe QUOKKA’s design characteristics, performance and operation, including a high count rate detector, installed in 2018.

        [1] K. Wood et al, J. Appl. Cryst. 51 (2018) 294.

        Speaker: Dr Deborah Wakeham (ANSTO)
      • 18:23
        Structure-property relationship and structural dynamics of layered transition metal oxides for sodium-ion battery applications 1m

        In recent years, the family of layered sodium-containing transition metal oxides, NaxMO2, where M=Ti, V, Cr, Mn, Fe, Co, Ni (or mixture of 2-3 of these elements), have attracted a great deal of attention due to their fascinating electronic, chemical and mechanical properties.[1, 2] Notably, NaxMn1-yMyO2, where M=Fe, Ni, Mg, Ti, are amongst the leading cathode materials for sodium-ion batteries (SIBs).[3] SIBs are particularly interesting, as they represent a low cost alternative to the ubiquitous lithium-ion batteries, owing to the larger abundance of sodium in the earth’s crust. At ambient conditions, the NaxMO2 compounds adopt various structural polymorphs (i.e. the so called O2-, O3-, P2- and P3-type structures) depending on the constituent transition metal(s), M, and the Na content.[4] Interestingly, the P2-type materials typically exhibit a higher capacity and cycle life, while the O2-type delivers a higher operating voltage.[5, 6] Recent determinations of the Na diffusion coefficient in these materials yield differences of up to five orders of magnitude depending on phase, composition and experimental technique.[7] It has been proposed that the electrochemical differences may be related to a higher Na-ion mobility in the P2-type structure, due to the presence of a more energetically favorable migration pathway.[8] In the present work, the structure, structural dynamics and electrochemical properties of P2-type Na0.67Mn0.8M0.2O2, M=Mg2+, Fe3+, Ti4+, are proposed to be investigated. In particular, the effect of the imposed change in Mn oxidation state as a result of the different valences of the substituted transition metals, M, and the associated variation in Jahn-Teller distortions from the Mn3+ ions in the structure is examined. In addition, the ability of crystal water to alter the Na diffusion rates by tuning the interlayer distances in the structure in hydrated versions of the compounds, Na0.67Mn0.8M0.2O2·yH2O, will be studied.

        [1] J. W. Fergus, J. Eur. Ceram. Soc., 2012, 32, 525-540.
        [2] K. Takada, H. Sakurai, E. Takayama-Muromachi, F. Izumi, R. A. Dilanian and T. Sasaki, Nature, 2003, 422, 53-55.
        [3] R. J. Clement, P. G. Bruce and C. P. Grey, J. Electrochem. Soc., 2015, 162, A2589-A2604.
        [4] M. H. Han, E. Gonzalo, G. Singh and T. Rojo, Energy Environ. Sci., 2015, 8, 81-102.
        [5] J. Billaud, G. Singh, A. R. Armstrong, E. Gonzalo, V. Roddatis, M. Armand, T. Rojob and P. G. Bruce, Energy Environ. Sci., 2014, 7, 1387-1391.
        [6] N. Yabuuchi, R. Hara, M. Kajiyama, K. Kubota, T. Ishigaki, A. Hoshikawa and S. Komaba, Adv. Energy Mater., 2014, 4, 1301453.
        [7] N. A. Katcho, J. Carrasco, D. Saurel, E. Gonzalo, M. Han, F. Aguesse and T. Rojo, Adv. Energy Mater., 2017, 7, 1601477.
        [8] N. Yabuuchi, K. Kubota, M. Dahbi and S. Komaba, Chem. Rev., 2014, 114, 11636-11682.

        Speaker: Dr Henrik Lyder Andersen (University of New South Wales)
      • 18:24
        Soft materials in food: Ultrasound induced modification of β-lactoglobulin into mesoscopic amyloid structures 1m

        β-lactoglobulin, a globular protein, is a major constituent of whey obtained from milk. It has been used as one of the model proteins for the synthesis and study of amyloid structures [1]. Proteins undergo structural modifications and aggregate into amyloid configurations that are rich in β-sheet elements in the secondary structure composition. Controlled synthesis has helped in study and characterization of amyloid fibrils. There have been attempts to study these structures in context of soft materials to be used in food systems and β-lactoglobulin being a milk protein, makes ideal choice for such work [2,3]. The past few decades have experienced abundant research on the fundamental aspects of ultrasonics and have been witness to sonochemistry developing into a complete discipline. Consequently, application based research has become the current focus in the field. Ultrasound being viewed among the potential green technologies of the future, multiple fields are attempting to adopt the technology and assimilate it. Ultrasonics find widespread use across multiple industries but is of particular interest for application in the food industry [4]. The application of ultrasound produces desirable results in food modification which have been found to be superior and more efficient as compared to those achieved by other processing technologies. Acoustic cavitation, produced during sonication, is the key to such improved outcomes, as in effect, it results in enhanced mass transfer, high local shear, confined zones of extreme heat and pressure at the minuscule level. With improved efficiencies demonstrated in operation, ultrasound is used in industrial processes such as extraction, emulsification, membrane-filtration, sonocrystallisation etc [4,5]. The present study is focused on β-lactoglobulin, to establish the characteristics of mesoscopic amyloid structures formed when the protein is treated with low-frequency ultrasound (20 kHz). This work is a step forward in that direction, as it elaborates on the relatively rapid and controlled synthesis of these amyloid structures. SANS (QUOKKA) is being used to study such synthesis to document the modifications taking place during amyloid formation with an ultrasonic stimulus, and to elaborate on the chemistry of such structural modifications in proteins. The ability to rapidly synthesise these structures with ultrasound, in their given state is important as it opens gateways for practical application of these structures in food systems, corresponding to theoretical propositions offered so far.

        References
        [1] C.C. van den Akker, M. Schleeger, M. Bonn, G.H. Koenderink, Structural Basis for the Polymorphism of β-Lactoglobulin Amyloid-Like Fibrils, in: Bio-nanoimaging, Elsevier, 2014, pp. 333-343.
        [2] R. Mezzenga, P. Schurtenberger, A. Burbidge, M. Michel, Understanding foods as soft materials, Nature materials, 4 (2005) 729.
        [3] Y. Cao, R. Mezzenga, Food protein amyloid fibrils: Origin, structure, formation, characterization, applications and health implications, Advances in colloid and interface science, (2019).
        [4] F. Chemat, M.K. Khan, Applications of ultrasound in food technology: processing, preservation and extraction, Ultrasonics sonochemistry, 18 (2011) 813-835.
        [5] M. Ashokkumar, Applications of ultrasound in food and bioprocessing, Ultrasonics sonochemistry, 25 (2015) 17-23.

        Speaker: Rachana Pathak (The University of Melbourne, ARC Dairy Innovation Hub Australia)
      • 18:25
        Self-Assembly of Long-Chain Betaine Surfactants: Effect of Tailgroup Structure on Wormlike Micelle Formation 1m

        Amidopropyl betaines are zwitterionic surfactants that exhibit viscoelastic properties, due to their ability to self-assemble into wormlike micelles and other extended micellar geometries. A range of amidopropyl betaine surfactant molecules containing C18 hydrocarbon tails, with differing levels of unsaturation and branching, were synthesised and analysed. The fatty acids used as targets for surfactant tail groups were stearic, oleic, isostearic, linoleic and linolenic acids. Small-angle neutron scattering (SANS), ultra-small angle neutron scattering (USANS) and rheology coupled to small angled neutron scattering (rheo-SANS) were employed to determine self-assembly in solution, micellar geometries and alignment of wormlike micelles under shear. Optimum wormlike micelle formation was achieved for the oleyl tailed surfactant. The more highly unsaturated molecules formed rodlike micelles, whereas the stearic-tailed molecule showed a pronounced Krafft point, and the isostearic-chained surfactant was entirely water-insoluble. These properties indicate that the oleyl-tailed betaine has the most potential to be exploited in applications, particularly where fluid control is imperative. This research has offered new insight into the micellar processes associated with amidopropyl betaines. It is evident that a subtle change in the tail group of amidopropyl betaines can modify the behaviour and solubility of these surfactants.

        Speaker: Veena Kelleppan (Monash University)
      • 18:26
        Critical measurement of the phase fine structures across the copper K-edge 1m

        Current applications of X-ray Absorption Fine Structure to low absorbing samples such as ultra-thin films in semiconductor and nano-devices have been limited. This is not the case for the phase component of the fine structure as it is generally orders of magnitude larger than the absorption component in the x-ray regime. We will present a technical methodology to retrieve the phase and absorption components of a copper thin film simultaneously at the XFM beamline (Australian Synchrotron) by applying the HERALDO technique across the copper K-edge. The results provide critical experimental benchmark for further theoretical development and has potential to delve into the phase equivalent of the XAFS technique.

        Speaker: Tony Kirk (La Trobe University)
      • 18:27
        Neutron and X-ray absorption spectroscopy studies of cobalt ion beam implanted TiO2 thin films 1m

        Transition-metal-doped oxides offer a potential route towards magnetic semiconductors which would pave the way for spintronic applications. Although much of the research work has been conducted on Co-doped TiO2, the room temperature magnetic properties of the system are still not well understood [1]. In this study, titanium dioxide (TiO2) thin films were deposited on a silicon substrate and doped with Co ions using ion beam implantation at multiple beam energies to create a uniform dopant layer. Neutron reflectometry and X-ray absorption spectroscopy were conducted at ANSTO to study the magnetic and electronic properties of TiO2 thin films.

        References:
        1. Cortie, D.L., et al., Enhanced Magnetization of Cobalt Defect Clusters Embedded in TiO2−δ Films. ACS Applied Materials & Interfaces, 2017. 9(10): p. 8783-8795.

        Speaker: Mr Abdulhakim Bake (Institute for Superconducting and Electronic Materials, University of Wollongong)
      • 18:28
        Disorder By Design: Energy, Pyrochlores and the Art of 'Stuffing' 1m

        In accordance with the Paris Climate Agreement, Australia will reduce its carbon emissions to 28% of its 2005 levels by 2030, with 24% of Australia’s electricity production to come from renewable sources. Two technologies being developed in Australia to assist with this transition include next-generation oxygen ion conductors and long-term storage for radioactive waste. The former is an attractive candidate, as it does not generate carbon dioxide in hydrogen gas fuel cells, and the latter is particularly important in closing the nuclear fuel cycle as Australia is a major exporter of uranium. However, significant technical issues have arisen in the development of these technologies, such as their lack of efficiency and short equipment lifespans.

        Pyrochlores of the structure A$_{2}$B$_{2}$O$_{7}$ have found immense applications in each of the above areas: oxygen ion conductors and for radioactive waste storage. However, this appears to be an apparent contradiction in requirements, with one requiring flexibility and movement in its anionic sublattice and the latter needing a robust lattice from which ions cannot escape. It is believed that the oxygen vacancies present in the pyrochlore structure allows for short-range disorder, whilst keeping the long-range order consistent.

        In this work, we are concerned with looking at the oxygen-vacancy disorder, and 'tailoring’ it to improve the applications of pyrochlores. We have done this by looking at ‘stuffed’ pyrochlores of the form A$_{2}$(A$_{0.67-x}$B$_{1.33+x}$)O$_{6.67+x/2}$. Increasing the amount of the larger A-type cation that normally occupies the eight-coordinate sites results in some of them occupying the six-coordinate B-site, in a process known as stuffing. It is envisaged that this increase in disorder in the cation sublattice will allow the possibility of engineering these for specific applications.

        The poster will focus on two parts: the synthesis and characterisation of the stuffed pyrochlores, and their physical applications.

        Two series of eleven stuffed pyrochlores, namely Yb$_{2}$(Yb$_{0.67-x}$Ti$_{1.33+x}$)O$_{6.67+x/2}$ and Tm$_{2}$(Tm$_{0.67-x}$Ti$_{1.33+x}$)O$_{6.67+x/2}$ with x = 0-0.67 have been synthesised using conventional solid-state methods and their long-range average structure characterised by Rietveld Refinement of conventional X-ray diffraction. The local short-range order has been characterised by Raman and infra-red spectroscopy.

        Further characterisation was undertaken using soft x-rays and x-ray powder diffraction at the Australian Synchrotron. It is also planned to determine the displacement of oxygen ions using the ECHIDNA Diffractometer at ANSTO. Since synthesising the two series of stuffed pyrochlores, various measurements have also been undertaken regarding their photocatalytic, associated band gaps, ionic conductivity and magnetic properties, yielding promising results.

        These results will be presented, along with a judgement as to whether inducing certain types of disorder within the pyrochlore structure can lead to them being purposely-built for their applications.

        Speaker: Bryce Mullens (University of Sydney)
      • 18:29
        Scientific Highlights from Quokka, the 40m Pinhole Small Angle Neutron Scattering Instrument 1m

        Quokka is the 40m pinhole Small Angle Neutron Scattering instrument (SANS) located at the OPAL research reactor at ANSTO, serving the needs of both domestic and international users [1]. Calibrated absolute scattering intensity measurements in a standard setup may be made over a range of wavelengths between 4 x 10-3 Å-1 and 0.7 Å-1.
        Outputs from Quokka have been published in diverse fields such as magnetism, metallurgy, mineralogy, structural biology, polymers, food science and soft matter. We present here a selection of recent scientific highlights.

        [1] K. Wood, J. P. Mata, C. J. Garvey, C. M. Wu, ... and E. P. Gilbert, J Appl Crystallogr, 2018, 51, 294-314.

        Speaker: Kathleen Wood (Australian Nuclear Science and Technology Organisation)
      • 18:30
        In Situ Synchrotron FTIR Microspectroscopy in Hydration Studies 1m

        Presented work was focused on odd-even effects in polysaccharide polyelectrolyte multilayers, that may influence their hydration content and the chemical environment of the water within them. Experiments were performed using polysaccharide polyelectrolyte multilayers (PEMs) composed of pharmaceutical grade fucoidan and chitosan. PEMs were studied under confinement using synchrotron FTIR microspectroscopy at increasing pressure, in order to isolate and measure infrared spectra of water within the PEM, without interference from bulk water. Complementary studies of the PEMs were carried out using lab-based in situ attenuated total reflectance Fourier transform spectroscopy (ATR FTIR) and quartz crystal microbalance with dissipation monitoring (QCM-D), as well as zeta potential measurements, to determine the quantity of adsorbed polymer, hydration content, film thickness, viscoelastic properties and surface charge during layer-by-layer deposition.
        Results revealed that the hydration of the PEM followed a saw-tooth profile, known as the odd-even effect, where the film increased hydration with fucoidan adsorption and dehydrated/densified with chitosan adsorption. The water structure within the film showed a lower degree of hydrogen bonding than water in the bulk electrolyte. However, the water structure/environment was independent of the terminating layer of the PEM, in spite of the alteration in percentage hydration water, indicating only a partial proof of the initial hypothesis for this multilayer system (hydration amount changes, hydration water environment does not).

        Speaker: Mr Piotr Pawliszak (University of South Australia)
      • 18:31
        Magnetism and Magnetic Materials Studied Using the Pelican Time-of-Flight Spectrometer 1m

        The study of magnetic materials using inelastic neutron scattering (INS) has a long history, dating back to some of the first INS experiments. The Pelican spectrometer is well suited to magnetic studies as the high flux, low background and non-magnetic construction provide ideal conditions for such experiments. Further the instrument is designed for polarisation analysis, a key technique in advanced magnetic characterisation studies. As part of the Pelican user programme, a diverse selection of magnetic properties and materials has been investigated. These include but are not limited to low dimensional quantum magnetism [1], excitations in lanthanoid single molecule magnets [2], frustrated magnetism [3]. In this contribution we will give an overview of some of these successful experiments and showcase future capabilities with the addition of a 7T magnet to the Pelican sample environment suite.

        1. M. Fujihala, T. Sugimoto, T. Tohyama, S. Mitsuda, R. A. Mole, D. H. Yu, S. Yano, Y. Inagaki, H. Morodomi, T. Kawae, H. Sagayama, R. Kumai, Y. Murakami, K. Tomiyasu, A. Matsuo, and K. Kindo Phys. Rev. Lett. 120 077201 (2018)
        2. M. Vonci, M.J. Giansiracusa, W. Van den Heuvel, R.W. Gable, B. Moubaraki, K.S. Murray, D. Yu, R.A. Mole, A. Soncini and C. Boskovic Inorg. Chem. 56 378 (2017)
        3. T. Haku, K. Kimura, Y. Matsumoto, M. Soda, M. Sera, D. Yu, R. A. Mole, T. Takeuchi, S. Nakatsuji, Y. Kono, T. Sakakibara, L.-J. Chang, and T. Masuda Phys. Rev. B 93 220407(R) (2016)
        Speaker: Richard Mole (ANSTO)
      • 18:32
        Update on the SPATZ Time-of-Flight Neutron Reflectometer at the OPAL Research Reactor 1m

        Neutron reflectometry is a powerful technique for studying the structure of surfaces and interfaces at the nanometer. The useful properties of neutrons allows for isotopic contrast variation in multi-component systems and being able to investigate phenomena under a wide variety of sample environments. At the OPAL Research Reactor there is currently one operating neutron reflectometer – PLATYPUS, however demand is sufficient that a second is needed. In September 2015, an agreement was signed between HZB and ANSTO to transfer the V18 ‘BioRef’ time-of-flight neutron reflectometer [1, 2], previously situated at the 10 MW BER-II Research Reactor, to the OPAL Research Reactor. During 2016, a joint team of ANSTO and HZB personnel carefully disassembled BioRef and packed it into shipping containers for transport to ANSTO. BioRef arrived at ANSTO in early 2017 and is now known as SPATZ (German for Sparrow) and is the 15th neutron-scattering instrument at OPAL.
        SPATZ has a vertical sample geometry, which complements PLATYPUS with its horizontal sample geometry. The vertical sample geometry will allow for use of sample environments which cannot be currently used on PLATYPUS due to geometry constraints and allows for wide-angle diffraction from multilayers and lamellar stacks. SPATZ will also be equipped for simultaneous infra-red spectroscopy and reflectometry experiments.
        The instrument views the OPAL cold neutron source (CNS) by taking the end position of the CG2B guide, which has recently been installed.
        SPATZ started hot commissioning in November 2018 and intends to start user experiments by the end of 2019. This presentation will provide an overview of the project, its current status, and future direction.
        [1] M. Strobl et al., Rev. Sci. Instrum. 82, 055101 (2011)
        [2] M. Trapp et al., Rev Sci. Instrum. 87, 105112 (2016)

        Speaker: Anton Le Brun (ANSTO)
      • 18:33
        Comparison between Hamamatsu C10900D and Xineos 3030HR detectors at IMBL for phase-contrast computed tomography of full mastectomy samples 1m

        We are developing phase-contrast computed tomography (PCT) using synchrotron sources that will be applied for medical breast imaging in the near future. This study is conducted in hutch 3B of the Imaging and Medical beamline (IMBL) of the Australian synchrotron. Currently, we are using two large-area flat-panel imaging detectors. The first detector is Hamamatsu CMOS Flat Panel Sensor C10900D, with CsI scintillator deposited directly on 2D photodiode array, with 1216 × 1232 pixels of 100 µm size in "fine mode" and maximum detected signal counts of 4000 (12 bit). The detector was used with minimum exposure time of 59 ms and frame rate of 17 fps. The second detector is Xineos CMOS flat panel detector, with medical-grade columnar CsI scintillator, with 2994x2997 pixels of 99μm pixel size and maximum counts of 16000 (14bit). The detector was used in Mag1 (70%) mode to achieve exposure time 25 ms and frame rate of 40 fps. Both detectors have high quantum efficiency and very low noise level, which is important for this type of application. Certain important parameters such as the X-ray energy, effect of the propagation distance, mean glandular dose were explored in this study using both detectors. Fresh full mastectomy samples with different types and grades of breast cancer lesions, as well as cancer-free samples, were used to approximate the real conditions of human breast imaging. The phase retrieval step that is added to the CT reconstruction process allows us to work with noisier images, offering a lower radiation dose delivered to the patients. The unique properties of synchrotron X-ray sources such as high coherence, energy tunability and high brightness are very important for producing low-dose PCT scans within short scanning times. These source characteristics needs to be complemented with a highly efficient detector having high frame rate, high resolution, large area and low noise level in order to maximize the outcomes for breast cancer imaging.

        Speaker: Seyedamir Taba (University of Sydney)
      • 18:34
        Recent highlights from the PELICAN spectrometer 1m

        The PELCIAN instrument is a cold-neutron time-of-flight spectrometer located at the Australian Centre for Neutron Scattering. The spectrometer has been in continuous user operation for the past five years. The instrument capabilities range from the study of quasi-elastic neutron scattering with a best resolution of 65 µeV, to the rapid measurement of phonon density of states. The instrument is well equipped for sample environment with our standard cryofurnace capable of measuring from 1.5 K to 800 K. While more complex sample environments such as gas sorption, light irradiation, electric fields and dilution temperatures have been commissioned and are in frequent use. In this contribution we shall give an overview of recent scientific highlights from PELICAN.

        Speaker: Richard Mole (ANSTO)
      • 18:35
        Nuclear techniques for Cultural Heritage at ANSTO 1m

        A strategic scientific research project Cultural Heritage has been initiated at the Australian Nuclear Science and Technology Organisation (ANSTO). The project aims to promote the access to the suite of nuclear methods available across the organisation, and the use of a non-invasive analytical approach in the field of cultural-heritage, archaeology, and conservation science. The latest scientific analytical tools, which are available under the operation of ANSTO, including neutron-, synchrotron- and accelerator-based techniques, have been increasingly demanded for a wide range of applications to heritage materials.

        Neutron Imaging (NI), in particular, has become a valuable means for research in these fields. The fundamental properties of the neutron — no electric charge, deep penetration power into matter, and interaction with the nucleus of an atom rather than with the diffuse electron cloud —make this sub-atomic particle the ideal probe to survey the bulk of a variety of heritage materials, such as metals, pottery, paintings, etc.

        In collaboration with Australian museum institutions and universities, and international experts, a series of forensic studies involving the neutron imaging beamline DINGO1 at the Australian Centre for Neutron Scattering (ACNS) will be showcased. NI was successfully used to characterise the structure, morphology and composition of cultural heritage objects without the need for sampling or invasive procedures. When integrated by complementary methods, NI data were able to shed light on the most advanced manufacturing processes developed by different cultures over time, determine the authenticity of work of art or provide information on the conservation status.

        Speaker: Filomena Salvemini (ANSTO)
      • 18:36
        Speckle Interferometry at IMBL - First Results 1m

        At IMBL inline phase-contrast imaging is typically used for imaging and tomography. This utilises Paganin's phase-retrival algorithm (Paganin et al. 2002) for boosting the signal to noise of the resultant images. However, this single-image algorithm does not permit the independent extraction of absorption and phase shift arising from a sample, nor can the dark-field signal be obtained.

        A number of alternative imaging methods such as grating-based phase-contrast, edge-illumination and speckle interferometry enable the independent extraction absorption, phase and dark-field signals (Mayo & Endrizzi 2018). Grating-based methods and edge-illumination require careful alignment and relative movement of two sets of gratings, or of a grating and detector, with images acquired at a succession of positions to obtain high quality data. Speckle interferometry and related tracking methods are experimentally less demanding, requiring only a mask and the ability to move it repeatably to different positions.

        The speckle mask creates a fine scale random pattern in the imaging plane and images are acquired with and without the sample in place. The local differences in intensity, position and contrast of the mask image with and without the sample are used to extract the different signals. For high-resolution speckle interferometry multiple image-pairs are acquired with the mask in different positions (Zdora et al. 2018). However, useful results at lower resolution can be achieved even with a single image pair (Berujon et al 2012).

        Here we present preliminary results from our first attempts to implement speckle interferometry at IMBL, including testing of single-image and multi-image methods including tomography.

        References

        Paganin D, Mayo SC, Gureyev TE, Miller PR, Wilkins SW (2002) Simultaneous phase and amplitude extraction from a single defocused image of a homogeneous object. Journal of Microscopy-Oxford 206:33-40

        Mayo S., Endrizzi M. (2018) X-Ray Phase Contrast Methods. In: Ida N., Meyendorf N. (eds) Handbook of Advanced Non-Destructive Evaluation. Springer, Cham

        Zdora MC, Thibault P, Deyhle H, Vila-Comamala J, Rau C, Zanette I (2018) Tunable x-ray speckle-based phase-contrast and dark-field imaging using the unified modulated pattern analysis approach. J Instrum 13

        Berujon S, Wang H, Sawhney K (2012) X-ray multimodal imaging using a random-phase object. Physical Review A 86:063813

        Speaker: Dr Sheridan Mayo (CSIRO Manufacturing,)
      • 18:37
        Australia’s contribution to an International Project to Generate a Consensus Standard Set of SAS Data to Benchmark Methods for SAS profile Prediction 1m

        The small-angle scattering (SAS) facilities and personnel at ANSTO’s Centre for Neutron Scattering and Synchrotron are part of an international project aimed at generating a set of SAS data sets from well-characterized biomolecules that can be used to benchmark different approaches to predicting SAS profiles from atomic coordinates (project description can be found at https://sas.wwpdb.org/?q=node/25). This project emerged from the deliberations of the International Union of Crystallography Commission (IUCr) on Small Angle Scattering (CSAS) and the Small-Angle Scattering validation task force (SASvtf) of the world-wide Protein Data Bank (wwPDB) that led to the 2017 publication guidelines for structural modelling of small-angle scattering data from biomolecules in solution (https://scripts.iucr.org/cgi-bin/paper?jc5010). The current project involves the efforts of 37 researchers with participants from 11 X-ray and 3 neutron scattering centres across Asia, Europe and North America.

        The specific objectives of the project are to measure SAS data at each of the participating facilities for 5 standard proteins with known structures using a common batch for each protein and appropriate standard buffer(s). The data sets are to be compared for consistency and then an agreed set will be made available to the research community. The data, measurement protocols and sources of material will be made available via a publicly accessible Website(s). A “Multi-SAXS Hub” web site is under development (Emre Brookes, University of Texas Health Science Center at San Antonio) to provide a single point from which different methods for scattering profile prediction can be accessed.

        Data have been acquired for the 5 selected proteins (RNase A, Lysozyme, Xylanase, Urate Oxidase, Glucose Isomerase) at a number of the participating facilities. We will present here the results obtained from the Australia Center for Neutron Scattering and Synchrotron, highlighting what is learned by having X-ray and neutron scattering data on each protein, as well as lessons learned to date from participating in this international project.

        Speakers: Anthony Duff (ANSTO), Andrew Whitten (ANSTO)
      • 18:38
        Residual Stresses, Metallurgical and Mechanical Properties of Laser Cladded Rail 1m

        Australia is home to the world’s seventh longest railway network, over 40,000km in length, which is depended upon for passenger and freight transport. Whilst the continued surge in rail infrastructure development brings economic growth, it also results in rapid rail degradation due to the direct wheel-rail head contact under high axial loads resulting in wear and rolling contact fatigue (RCF).

        Laser cladding is a promising maintenance strategy to regenerate the rail surface by using a high energy laser to metallurgically bond a metallic powder to the substrate surface, forming high-quality, hard facing layer. However, the highly localised heat input and repeated cycles solidification, thermal expansion coefficient mismatch and phase transformations all contribute to a high residual stress state which is detrimental to the rail fatigue resistance when combined with the rail-wheel contact stresses.

        The aim of this project is to develop a novel cladding alloy, SS415, that has the combined advantages of excellent abrasion resistance, hardness and improved toughness which will increase the service life of hypereutectoid rails. A low residual stress state in the clad rails is imperative for rail performance and accurate evaluation of residual stresses using non-destructive neutron scattering techniques is critical in the prediction of fatigue life.

        Our first residual stress measurements on a SS415 clad rail were taken on Kowari strain scanner at ANSTO. The preliminary results will be discussed and correlated with the metallurgical and mechanical properties of the laser repaired rail.

        Speaker: Olivia Kendall
      • 18:39
        Pattern Formation in the Membranes of Bicontinuous Cubic Phases Based on Star-Polyphiles 1m

        Bicontinuous cubic phases are of widespread interest as they are thought to play an important role in nature, and have found a large variety of applications in fields including drug delivery, contrast agents, food science, biosensors, and nanomedicine.
        Here we present bicontinuous cubic phases in which the hydrophobic membrane is locally de-mixed into hydrocarbon and fluorocarbon domains [1], whereby the hydrocarbon fluorocarbon patterns can be tuned based on composition.
        The cubic phase is self-assembled from a mixture of double chain surfactants and star-polyphiles [2]. The latter are small molecules consisting of 3 mutually immiscible chains attached to a common center; a hydrocarbon, fluorocarbon and a water soluble oligo-ethylene glycol chain [3,4].
        The focus of this presentation will be on detailed SANS contrast variation data in comparison to scattering simulations.

        [1] de Campo, L.; Castle, T.; Hyde, S. T., Interface focus, 7 (4), 20160130 (2017)
        [2] Hyde S.T., de Campo L., Oguey Ch., Soft Matter, 5, 2782-2794 (2009)
        [3] de Campo, L.; Moghaddam, M. J.; Varslot, T.; Kirby, N.; Mittelbach, R.; Sawkins, T.; Hyde, S. T., Chem. Mat, 27 (3), 857-866 (2015)
        [4] de Campo L., Varslot T., Moghaddam M., Kirkensgaard J., Mortensen K., Hyde S.T., PCCP, 13(8), 3139-3152 (2011)

        Speaker: Dr Liliana de Campo (Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organization (ANSTO))
      • 18:40
        The National Deuteration Facility, and support of neutron scattering for structural biology 1m

        The National Deuteration Facility (NDF) at the Australian Nuclear Science and Technology Organisation (ANSTO) provides deuteration for a diversity of molecules and applications, including the deuteration of proteins for solvent contrast variation of multi-subunit biological assemblies.

        Many of the macromolecular functions of life and disease involve dynamic protein interactions. Observing, and mapping, large scale domain movements is a strength of method of solution scattering. Small angle x-ray scattering can quickly provide macromolecular envelope information. Extending on this is the method of small angle neutron scattering (SANS) using solvent contrast variation, and subunit-specific labelling by deuteration, which enables identification and mapping of relative dispositions of the subunits within the macromolecular envelope.

        Recent illustrative examples of structural characterisations using deuteration and SANS include: [1] the trimeric Proteus mirabilis ScsC protein bound to ScsB; [2] the BAMLET complex of alpha-lactalbumin and oleic acid; and [3] multiple complexes of syntaxin and munc18.

        [1] Disulfide isomerase activity of the dynamic, trimeric Proteus mirabilis ScsC protein is primed by the tandem immunoglobulin-fold domain of ScsB.
        Furlong, E. J., Choudhury, H. G., Kurth, F., Duff, A. P., Whitten, A. E. & Martin, J. L.
        Journal of Biological Chemistry, 293, 5793-5805. (2018) http://dx.doi.org/10.1074/jbc.RA118.001860

        [2] Neutron scattering shows a droplet of oleic acid at the center of the BAMLET complex.
        Rath, E. M., Duff, A. P., Gilbert, E. P., Doherty, G., Knott, R. B. & Church, W. B.
        Proteins, 85, 1371-1378. (2017) http://dx.doi.org/10.1002/prot.25298

        [3] Studying Munc18:syntaxin interactions using small-angle scattering.
        Whitten, A. E., Jarrott, R. J., Hu, S. H., Duff, A. P., King, G. J., Martin, J. L. & Christie, M. P.
        Methods in Molecular Biology, 1860, 115-144. (2019). http://dx.doi.org/10.1007/978-1-4939-8760-3_7

        Speaker: Anthony Duff (ANSTO)
      • 18:41
        KOWARI Residual Stress Scanner at ANSTO 1m

        The OPAL research reactor at ANSTO has several instruments available for materials science and engineering applications. The KOWARI instrument has a unique non-destructive ability to measure stresses locked-in due to manufacturing processes in various materials such as metals, ceramics, and composites. Often residual stresses can be greater than stresses generated by applied load, therefore from a design and structural integrity point of view they need to be understood and quantified in the same way as external stresses. Diffraction base techniques provide vital non-destructive measurements of residual stresses on the surface and deep within the interior of components, in small test volumes, in thin and thick specimens.
        Those measurements can be carried out on real engineering components, or test samples with minimal preparation. This information provides direct impact into the optimization of modern manufacturing processes, improved product reliability, enhanced design performance, reduced production cost, and extended life of significant engineering assets (e.g. power-station utilities, gas pipelines, aircrafts, trains, etc.). The results show case how you can use the KOWARI instrument to solve material and engineering problems on large and small scales.

        Speaker: Anna Paradowska (ANSTO)
      • 18:42
        EFFECT OF Mo + Cr CODOPING LEVELS ON THE PHOTOCATALYTIC PERFORMANCE OF SOL-GEL DERIVED AND ION IMPLANTED TIO2 THIN FILMS 1m

        Titania (TiO2) is one of the most widely used photocatalysts with applications in water splitting, air purification and dye sensitised solar cells. However, its wide band gap (3.0–3.2 eV) makes it inefficient under visible light. There is potential to lower the band gap and improve photocatalytic efficiency through codoping and ion implantation by transition metal ions.

        In present work, uniformly codoped TiO2 thin films of varying Mo and Cr concentrations (0–1.00 mol% for each dopant) were fabricated using spin coating and deposited on fused silica substrates. All films were annealed at 450°C for 2 h to recrystallise the TiO2. The undoped samples were subjected to ion implantation by Mo, Cr, and both Mo + Cr at 1 x 1014 atoms/cm2 and annealed again at 450°C for 2 h. The films were characterised to determine their mineralogical and surface properties using X-ray diffraction, Raman spectroscopy, atomic force microscopy, secondary ion mass spectroscopy, and X-ray photoelectron spectroscopy. Photocatalytic activity was examined by testing the absorbance of methylene blue solution (UV-vis spectroscopy) after irradiation by UV light for different time periods.

        In the uniformly codoped films, the crystallinity of the films increased when the codopant level was below the solubility limit of the dopants. However, above the solubility limit, dopant precipitation at grain boundaries resulted in grain pinning and amorphisation, decreasing the crystallinity of the films. Overall, it was found that photocatalytic performance decreased with increase in codopant content owing to lattice strain. Ion implantation of undoped thin films with Mo and Mo + Cr improved the photocatalytic performance of the film. It is thought that Cr increased the formation of oxygen vacancies which lowered the band gap and improved photocatalytic efficiency.

        Speaker: Ms Amanda Chen (UNSW Sydney)
      • 18:43
        Linking microstructure to rheology for wormlike micelles 1m

        Wormlike micelles (WLMs) are elongated, thread--like surfactant aggregates that form thermodynamically under certain conditions. At sufficiently high concentrations, WLMs overlap and entangle with each other and this change in microstructure causes a rapid increase in viscoelasticity and zero--shear viscosity. Moreover, it provides significant shear--thinning character, a type of `non--Newtonian' flow behaviour. These properties are very useful in a variety of industries and products, including as personal care products, drag reducing agents and fracturing fluids for oil and gas field stimulation. Despite their ubiquity, very few studies have investigated mild, non--toxic WLMs (like those found in personal care products) at concentrations relevant to industry formulations. Moreover, no model exists that is able to incorporate and link the known microstructural features of WLMs to the bulk rheological properties to which they give rise.

        Here, we are seeking to investigate and link the microstrucutre and bulk rheology of WLMs formed by cocamidopropyl betaine (CAPB) and sodium laureth sulfate (SLES) surfactants. To do so, we have conducted small--angle neutron scattering (SANS) measurements on CAPB/SLES WLM samples whilst at an applied shear rate, a technique known as rheo--SANS. From this study we have been able to observe shear--induced alignment of WLMs via anisotropy in the 2D scattering pattern and, for the first time, we are attempting to fit full 2D scattering patterns. This will allow us to quantitatively determine the degree of alignment of WLMs with the direction of shear, as well as other physical parameters within the SANS range including cross--sectional radius and persistence length. By way of analysis and comparison of these data with bulk rheology data, we aim to establish structure--function relationships for predictive and self--consistent modelling of WLM rheology.

        Speaker: Mr Joshua King (Monash University)
      • 18:44
        In-Situ Solar Simulation for Organic Photovoltaics 1m

        Accurate simulation of the solar spectrum is a prerequisite for research into photovoltaic stability and efficiency. Organic photovoltaics (OPV) have gained popularity in recent years due to their low cost of production, physical flexibility, high tunability and light weight. As interest in OPV continues to grow, the need arises for solar simulation to be employed in increasingly diverse environments and in conjunction with techniques such as UV/Vis spectroscopy, mass spectrometry and Small-Angle Neutron Scattering (SANS). In this work, a solar simulator is designed which can illuminate up to three samples in parallel in the BILBY beamline. The solar simulator is of a modular design and based around a tungsten halogen light source used to replicate the solar spectrum. This light source can also be interchanged with sources of different wavelengths for use in applications such as photochemistry and the biomolecular sciences. We aim to show results for a typical OPV system in-situ with SANS on BILBY.

        Speaker: Neil Anderson (ANSTO)
      • 18:45
        Exploring diffusion mechanisms in oxide-ionic conductive single crystals 1m

        The development of efficient and cost-effective solid oxide fuel cells (SOFCs) will allow hydrogen or other low-carbon fuels to replace hydrocarbon fuels in commercial energy-generation applications. A wide variety of oxide structure classes are being explored in an effort to discover SOFC electrolyte and electrode materials with competitive ionic conductivity in the “intermediate” temperature range (450-600 °C). In order to rationally design and tune these materials for better performance, a clear understanding of the causes and mechanisms of ionic conductivity in the most promising materials is essential.

        Our work utilises a combination of experimental and theoretical methods to investigate the structural and dynamic origins of oxide ion mobility in diverse solid oxide materials. We have used the optical floating-zone furnace facility recently installed at Durham University to grow single crystals of conductive scheelites ($\mathrm{CeNb}_{1-x}M_{x}\mathrm{O}_{4+\delta}$ and $\mathrm{LaNb}_{1-x}M_{x}\mathrm{O}_{4+\delta}$, M = V, Mo, W), apatites ($\mathrm{(La,Bi)}_{9.33+x}\mathrm{Si}_{6}\mathrm{O}_{26\pm\delta}$) and “hybrid” hexagonal perovskites ($\mathrm{Ba}_{3}\mathrm{Nb}M\mathrm{O}_{8.5}$, M = Mo, W), in many cases for the first time. These crystals have enabled a variety of experiments to be performed, including single-crystal x-ray and neutron diffraction, directional quasielastic neutron scattering, and oriented $^{18}$O tracer diffusion measurements. Our poster will present new insights obtained from these studies concerning the roles of ionic order and disorder, interstitial site behaviour, low-energy diffusion pathways, and cation coordination environments on efficient ionic conductivity in some of the mentioned materials.

        Speaker: Josie Auckett (Durham University)
      • 18:46
        Corrosion at the Metal-Glass Interface in HIPed Nuclear Wasteforms 1m

        A common approach to the immobilisation of nuclear wastes produced in the nuclear fuel cycle is to incorporate them in a borosilicate glass and dispose this “wasteform” within a geological repository. These glass-based wasteforms are known to corrode in groundwater in the repository over thousands of years and thus research has focused on investigating the mechanisms of glass dissolution and corrosion to understand and predict the stability of the radionuclides in the glass structure. ANSTO has developed hot isostatic pressing (HIP) to consolidate nuclear waste into an appropriately designed wasteform to significantly reduce storage volumes and to minimise the formation of secondary waste streams and this technology can be applied to glass. In this process, the liquid waste and glass forming additives are mixed and then dried to produce a powder that is melted at high temperatures in a specially designed metal canister which is compacted using high pressure argon gas. However, corrosion may occur at the contact zone between the glass and the stainless-steel HIPing container and this may impact the stability of the waste form structure in the long term within the repository. Therefore, further understanding of the effects of temperature and pressure during the HIPing process on the corrosion of the glass in the contact zone with the stainless-steel container is required. This is of particular importance since this interface is potentially the first exposure point to groundwater in a geological repository.

        This collaborative project between ANSTO and UNSW investigated the corrosion and stability of the glass-stainless steel interface of three HIPed nuclear waste glass compositions. The compositions that were used include International Simple Glass (ISG) which is a benchmark for glass corrosion experiments, UK Mixture Windscale Glass (MW), and French R7T7 Glass (SON68) which are used internationally. The glass frits were prepared by mixing, drying, and calcining of the appropriate precursor powders, and subsequently converted to simulant wasteforms by both melting in a furnace and HIPing. The glass compositions and the resultant interface with the HIP container was characterised using scanning electron microscopy (SEM) to determine the microstructural characteristics and homogeneity and energy dispersive spectroscopy (EDS) to determine the elemental distribution. Corrosion experiments were performed on sections of the HIPed samples by placement in water at 90°C over time periods ranging from 7 to 60 days to accelerate the corrosion. Similar microstructural analyses of the interfacial regions were conducted on the corroded samples and then compared with the un-corroded control samples. The outcomes from the research will provide critical data on stability of different glass compositions after HIPing in steel containers which can help to assess the safety of HIPed nuclear waste glass storage underground for long time periods >1000 years.

        Speaker: Keenan Burrough (UNSW/ANSTO)
      • 18:47
        Theoretical study of manganese melilites and related structures 1m

        Manganese melilites and related compositions1-8 with chemical formula of A2MnC'2O7 (A1+: Na, K, Rb, Cs; C’5+: As, V, P and A2+: Ca, Sr, Ba; C’4+: Si, Ge) were studied theoretically using ab initio density function theory. The relative stability of different phases was approximated by comparing relaxed crystal structure energies. Further calculations of the magnetic structure and super-super exchange parameters of selected melilite structures were also performed. The calculated results mostly agree with the limited set of experimentally measured magnetic and crystal structures5, 8-10 and suggest interesting pathways for further research.

        1 M. Sale, M. Avdeev, Z. Mohamed, C. D. Ling, P. Barpanda, Dalton Trans., 46, 6409-6416 (2017)
        2 A. C. Keates, Q. Wang, M. T. Weller, J. Solid State Chem., 210, 10-14 (2014)
        3 M. Gabelica-Robert, Comptes Rendus Série II, 293, 497-499 (1981)
        4 P. Barpanda, M. Avdeev, C. D. Ling, J. Lu, A. Yamada, Inorg. Chem., 52, 395-401 (2013)
        5 A. El Maadi, A. Boukhari, E. M. Holt, S. Flandrois, Comptes Rendus Série II, 318, 765-770 (1994)
        6 A. El Maadi, A. Boukhari, E. Holt, J. Chem. Crystallogr., 25, 531-536 (1995)
        7 F. Erragh, A. Boukhari, B. Elouadi, E. M. Holt, J. Cryst. Spect. Res, 21, 321-326 (1991)
        8 Q. Huang, S.-J. Hwu, Inorg. Chem., 37, 5869-5874 (1998)
        9 P. Barpanda, T. Ye, M. Avdeev, S.-C. Chung, A. Yamada, J. Mater. Chem. A, 1, 4194-4197 (2013)
        10 B. Yahia Hamdi, E. Gaudin, J. Darriet, Z. Naturforsch. B Chem. Sci., 62, 873 (2007)

        Speaker: Matthew Sale (University of Sydney)
      • 18:48
        Optimization of Ion Implantation Parameters for Photocatalytic Coatings on Conducting and Insulating Substrates 1m

        Titanium dioxide (TiO2) is the most commonly used photocatalyst which is activated by UV irradiation to generate electron-hole pairs that can contribute to the destruction of inorganic compounds to water and CO2. The photoeffciency of TiO2 is limited in visible light due to its wide band gap and high photo-induced charge recombination rates. A potential solution to this issue is to dope TiO2 with transition metals via low energy ion implantation (LEII) technique available at the ANSTO Centre for Accelerator Science. Previous LEII work has shown that the as-implanted dose can be significantly different from the intended nominal value when implanting insulating substrates. This can impact on the accuracy of the dosage, particularly for designing advanced materials for photocatalytic applications. Thus there is a need to investigate the effects of implanting different metals in a photocatalytic coating deposited on insulating and conducting substrates in order to determine the effect of implantation parameters on the accuracy of the implantation dosage.

        This collaborative Honours thesis project between UNSW and ANSTO investigates the correlation of implantation accuracy with coating type, conductivity of substrates, and dopant type to optimise the ion implantation process. A semiconducting photocatalytic TiO2 thin film was deposited by spin coating of sol-gel precursor (titanium isopropoxide and isopropanol) on silicon and fluorine doped tin oxide (FTO) glass substrates followed by annealing at 450°C for 2 h. The TiO2 coated substrates were implanted with Mo and Cu ions at nominal doses of 1x1014 to 1x1016 atom/cm2. The implanted samples were characterized using both particle induced X-ray emission (PIXE) and Rutherford backscattering spectroscopy (RBS) at ANSTO to determine the actual concentration of implanted dopant. The microstructural and mineralogical characteristics of the implanted samples were characterized at UNSW using scanning electron microscopy (SEM) and X-ray diffraction (GAXRD), respectively. Atomic force microscopy (AMF), X-ray photoelectron spectroscopy (XPS) and laser Raman spectroscopy were employed to determine the surface roughness, grain size, surface composition and confirmation of mineralogy of TiO2 coated samples before and after implantation. Photocatalytic testing using dye degradation (methylene blue) under UV and solar irradiation were conducted to determine the effect of implantation on photocatalytic performance. The outcomes of this research will provide critical data which will allow for increased accuracy of ion implantation on substrates of varying conductivity and allow for optimization of implantation dosage for enhanced performance for different applications.

        Speaker: Ms Jialuo Ke
      • 18:49
        Structural Characterisation of a high Na-ion conductor 1m

        Rechargeable lithium ion batteries have been in commercial use for almost three decades now. They are ubiquitous in our society and we can hardly imagine a life without them. Given the challenges ahead, such batteries might help to slow down the rate at which our planet warms. Two large scale approaches that can help here are the storage of sustainably produced renewable energy and the use of batteries in electric cars (re-charged with sustainably produced electricity). Several widely publicised cases of exploding mobile phones (due to highly flammable organic electrolytes) have highlighted critical safety concerns for widespread use of such batteries in cars. To address these safety issues, the highly flammable organic liquid electrolytes can be replaced by solid electrolytes to form all-solid-state batteries (ASSBs). In this context, the development of solid electrolytes for sodium ion batteries is crucial.

        One of the systems that we are investigating, and the subject of this presentation, is the perovskite-type Na1/2-xLa1/2-xSr2xZrO3 system. The x=1/6 member of the system, i.e. Na1/3La1/3Sr1/3-ZrO3 (NLSZO) was recently published by Zhao et al. [1] They reported the structure to have a cubic crystal system with the space group P213, in agreement with the data for SrZrO3 (PDF No. 74-2231) as proposed in 1992 by Roosmalen et al. [2] However, it has been demonstrated by Kennedy et al. that the transition to the cubic phase for SrZrO3 is only possible at or above 1373 K with the space group Pm-3m [3]. Under ambient conditions SrZrO3 is reported to have an orthorhombic superstructure.

        Given the high ionic conductivity reported for the system, it is important to determine its structure reliably and with the best available data. The powder data we have collected for our sample indicate that the symmetry is indeed lowered to orthorhombic. The detailed structural characterisation based on those data will be reported.

        References:

        [1] Y. Zhao, Z. Liu, J. Xu, T. Zhang, F. Zhang, X. Zhang (2019). Synthesis and characterization of a new perovskite-type solid-state electrolyte of Na1/3La1/3Sr1/3ZrO3 for all-solid-state sodium-ion batteries. Journal of Alloys and Compounds 783, 219 - 225.

        [2] J. A. M. van Roosmalen, P. van Vlaanderen, E. H. P. Cordfunke (1992). On the structure of SrZrO3. Journal of Solid State Chemistry 101, 59 - 65.

        [3] B. J. Kennedy, C. J. Howard, B. C. Chakoumakos (1999). High-temperature phase transitions in SrZrO3. Physical Reviews B 59, 4023 - 4028.

        Speaker: Mr Frederick Tiger Yang (The University of Sydney)
      • 18:50
        Simultaneous SAXS and WAXS ion track recovery studies on metallic glasses and consequences on their magnetization properties 1m

        Amorphous metals, also called metallic glasses, are metallic alloys with a disordered non-crystalline atomic structure. There is a high level of interest in metallic glasses as consequence of their particular structure, lacking of medium and long range order leading to interesting physical properties such as high mechanical strength, great wear and corrosion resistance, and high elasticity [1]. Furthermore, such interesting mechanical properties combined with permanent magnetization (as in Fe- and Co-based alloys) have motivated an important emerging field through the recent development of nanocrystalline materials from metallic glasses for magnetic applications. Nanocrystalline Fe based alloys exhibit outstanding magnetic properties characterized by a very low coercivity and very high saturation magnetization.

        Ions at energies of some MeV per nucleon lose their energy predominantly to the electronic system when passing through matter. In this process, energy transfer from the electronic system to the atoms due to electron-phonon coupling may finally lead to the formation of long columnar defects along the ion trajectories, so called ion tracks [2,3].

        Simultaneous synchrotron based small and wide angle X-ray scattering (SAXS and WAXS) study is presented on swift heavy ion irradiated amorphous Fe –B based metallic glasses. Melt-spun ribbons with cylindrical ion tracks produced by irradiation with 2 GeV U and 2.2 GeV Au ions were annealed in situ with temperatures of up to 440°C. Ion track recovery followed by crystallization of the alloy is observed. While the ion track radius remained approximately constant during annealing, the SAXS scattering intensities of individual monodisperse ion tracks decreased until vanishing before the onset of crystallization. Subsequently SAXS/WAXS indicates the nucleation of $\alpha$-Fe and Fe$_{3}$B nanocrystals. The time evolution of the particle size distribution revealed a nucleation dominated crystallisation process. Through magnetic measurements of the metallic glasses irradiated to different doses, ion tracks induced microstructural changes in the material were found to reduce the magnetic coercivity of the nanocrystalline material.

        [1] A. Inoue and A. Takeuchi, Acta Materialia (2011), doi:10.1016/j.actamat.2010.11.027
        [2] P. Kluth et al., Phys. Rev. Lett. 101 (2008) 175503
        [3] M. D. Rodriguez et al., J. of Non-Cryst. Solids 358 (2012) 571

        Speaker: Dr Matias Rodriguez (Department of Electronic Materials Engineering, The Australian National University, Canberra, Australia / School of Science, University of New South Wales - Canberra, Australia )
      • 18:51
        Virtual recovery of text from an ancient inscribed lead scroll using neutron tomography 1m

        The artefact in study is an ancient lead scroll with an inscriptions inside, however, its purpose and origin are unknown. Many ancient cultures used metal tablets as a writing media for various purposes - prayers of protection, ballots, contracts, and curses for example. Once inscribed, these tablets were rolled or folded and placed in a variety of places determined by their purpose ie. cisterns and wells for curses, or burial sites for protection. Lead and tin were typically used for curses and ill-wishes, however there have been examples of official documents and private letters found on lead tablets also.
        These tablets are often found to be corroded and fragile as a result of their burial environments, which can make it difficult to determine the nature of their inscriptions. Physically unrolling these delicate ancient documents can result in fragmentation, crumbling, and overall permanent damage and loss of text. Thus using non-destructive techniques are the best way forward for the study of these fragile glimpses into the past.
        Synchrotron X-ray CT was unable to penetrate the ~2cm thick lead scroll, however, neutron tomography successfully imaged through the entirety of the scroll. The results were unprecedented, revealing four individual tablets rolled up in the scroll. Using VG Studio the length of each lead sheet and thickness of each lamellae can be measured. Additionally virtual unrolling of the sheets and extraction of text has begun, also using VG Studio.

        Speaker: Ms Carla Raymond (Macquarie University)
      • 18:52
        Integrated Nanoindentation and Modelling Approaches to Determine Ion Induced Hardening Behaviour in AA6061 and MA957 1m

        Materials used in nuclear applications are exposed to radiation which causes changes to their properties, most significantly with regard to the hardness and microstructure. The present work investigates the changes in hardness resulting from heavy ion irradiation damage in aluminium alloy AA6061-T6 after irradiation with 12 MeV Au ions and contrasts it with the changes in the hardness of ferritic alloy MA957 irradiated using He ions at various energies. The mechanical test data was obtained using the oblique cross section (OCS) nanoindentation method for AA6061-T6 while the top down method was used for MA957 allowing for good depth resolution and sharper peaks.

        A multiscale assessment framework was proposed through combinatorial modelling approaches including the Monte Carlo (SRIM) simulation of ion irradiation and continuum finite element modelling to account for damage saturation. The simulation results were compared and validated against the experimental data to elucidate the hardening effect resulting from ion irradiation and the resultant changes in the hardness profile. The work was able to determine the stress distribution beneath the indenter while revealing the stratified nature of damage in ion beam irradiation along with the occurrence of complex plastic deformation in the irradiated zones.

        Data from literature on neutron irradiation studies with regard to hardening rates, dpa dependence and flow stress for bulk polycrystalline specimens was used to analyse the stratified layers produced from ion irradiation at the micromechanical scale in the FE model. This methodology was used to predict the hardening response of ion irradiated materials that are thermodynamically stable and show hardening rates independent of irradiation dose.

        Speaker: Mr Benjamin Muffett (Student UNSW )
      • 18:53
        Correlative Dynamics of Filamentous Fungal Adhesion on Anti-Fungal Paint and Polyester Surfaces using Synchrotron Macro ATR-FTIR Microspectroscopy 15m

        Fungal colonisation of different indoor and outdoor substrata is one of the common issues that causes damage and degradation of metallic surfaces. It can be a source of infection for immunocompromised and/or sensitive individuals. In this study, we investigated the initial conidia attachment dynamics of three fungal strains, including Aspergillus niger ATCC 9642, Aureobasidium pullulans ATCC 9348 and Epicoccum nigrum ATCC 42773 on (i) polyester coated surfaces and (ii) polyethylene terephthalate-coated paints. The biochemical information of the initial conidia attachment, particularly saccharides, proteins and lipids, was characterised using synchrotron macro ATR-IR microspectroscopy and correlated with their physical appearance from SEM analysis. The results obtained indicated that during initial interactions with surfaces, the saccharide composition played a significant role in facilitating fungal colonisation on these surfaces. This study also demonstrated synchrotron macro ATR-FTIR as a powerful analytical tool for gaining a better understanding in the filamentous fungal adhesion on these specific surfaces.

        Speaker: Arturo Aburto Medina (RMIT University)
  • Tuesday, 3 December
    • 08:00 → 09:00
      Registration
    • 09:00 → 09:15
      Session 0: Opening Remarks - Day 2
    • 09:15 → 09:45
      Plenary: Silvia Frisia & Andrea Borsate
      • 09:15
        SR-micro XRF and Transmission Electron Microscopy: advances in the accuracy of past climate and environmental interpretation from carbonate crystals data. 30m

        Investigation by high resolution Synchrotron-Radiation based micro X-ray fluorescence (SR-μXRF) at the Australian Synchrotron coupled with Transmission Electron Microscopy (HR-TEM) and both terrestrial and marine carbonates imposes uncertainties on the boundary between stages of crystal nucleation and growth and diagenetic processes. This has profound implications on the correct (accurate) interpretation of chemical data that are proxies of climate parameters are interpreted. An accurate interpretation of climate proxies is necessary when such proxies are transformed into temperature or rainfall quantitative data that are used to validate climate models.
        In the last 20 years, speleothems (defined as cave secondary mineral deposits) consisting of calcium carbonate have proven to be exceptional archives of past climate and environmental changes that parallel ice cores for their accuracy. However, amongst many published speleothem-based records, there are uncertainties that lead to anecdotal evidence. This may generate skepticism in the quality of data, particularly by modelers who do not have knowledge about how proxy data are captured by speleothem (or ice) crystals. Such knowledge is grounded on a thorough nanoscale investigation of crystallization processes.
        HR-TEM investigation of in-situ products of in-situ crystallization experiments suggest that there are many pathways leading to speleothem carbonates formation, which capture chemical species differently. This translates into concentrations of elements that defy thermodynamic partitioning. When chemical concentration variabilities of trace elements are interpreted without knowledge about how these are incorporated in the final product of crystallization, interpretations are uncertainty-ridden.
        Most carbonates used to reconstruct past climates and environments grow via particle-mediated and/or formation of metastable phases. By contrast, the classical ion attachment to growth sites theory appears to be defied by free-energy barriers. The occurrence of diverse pathways and, consequently, the climatic significance of climate proxy data incorporated in speleothem crystals is detected through nano- and micro-scale techniques.
        Through HR-TEM observations of “instant” cave precipitates, we found that organic compounds and particulate influence the way hydrological markers, such as Sr, are incorporated in different crystal fabrics. SR-micro XRF mapping of stalagmites from the Indo-Pacific region show that Sr is an annual hydrologic marker and, commonly, an increase in its concentration occurs in compact (non-porous) calcite. This phenomenon is indicative of dry conditions. However, we also documented Sr concentration increase in layers consisting of porous fabric. This fabric is commonly formed during wet conditions. The discrepancy, which was highlighted by using SR-micro XRF mapping, was solved by documenting crystal growth from fast and slow drips at the nanoscale in the cave where speleothem show Sr increase in porous fabrics. Fast drips (representative of “wet” conditions) yielded calcite nanocrystals bridged by amorphous particulate rich is Si, K, and Al. This likely originated from silicate weathering and, thus, includes the excess Sr within the open fabric. The presence of particulate itself also inhibits coalescence of nanocrystals, leaving porosity in between the growth units.
        We will show examples of how SR-micro XRF mapping enhances the power of petrography and geochemistry as palaeo-climate tools and how High-Resolution Transmission Electron Microscopy is a necessary complementary technique. Our examples will briefly touch the origin of other carbonates whose formation through nanoscale attachment has revolutionized Earth’s history.

        Speakers: Prof. Silvia Frisia (University of Newcastle), Dr Andrea Borsato (University of Newcastle)
    • 09:45 → 10:15
      Plenary: AS - Stephen Wilkins Medal
    • 10:15 → 10:45
      Morning Tea 30m
    • 10:45 → 12:15
      Session 14: Structural biology and biological systems - T5 (Part 3)
      • 10:45
        Nano and Microstructure Investigation of Silk Fibroin-Based Hydrogels for Biomedical Applications: A Small Angle Scattering 15m

        Regenerated Bombyx mori silk fibroin (RSF) is a widely recognized protein for biomedical applications; however, its hierarchical gel structure is poorly understood. Here, the hierarchical structure of photocrosslinked RSF and RSF-based hybrid hydrogel systems: (i) RSF/Rec1-resilin and (ii) RSF/poly(N-vinylcaprolactam (PVCL) is reported for the first time using small-angle scattering (SAS) techniques [1]. The structure of RSF in dilute to concentrated solution to fabricated hydrogels were characterized using small angle X-ray scattering (SAXS), small angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) techniques. The RSF hydrogel exhibited three distinctive structural characteristics: (i) a Porod region in the length scale of 2 to 3nm due to hydrophobic domains (containing β-sheets) which exhibits sharp interfaces with the amorphous matrix of the hydrogel and the solvent, (ii) a Guinier region in the length scale of 4 to 20nm due to hydrophilic domains (containing turns and random coil), and (iii) a Porod-like region in the length scale of few micrometers due to water pores/channels exhibiting fractal-like characteristics. Addition of Rec1-resilin or PVCL to RSF and subsequent crosslinking systematically increased the nanoscale size of hydrophobic and hydrophilic domains, whereas decreased the homogeneity of pore size distribution in the microscale. The presented results have implications on the fundamental understanding of the structure–property relationship of RSF-based hydrogels [1].

        References
        [1] J. L.Whittaker et al, International Journal of Biological Macromolecules 114 (2018) 998–1007.

        Speaker: Jitendra Mata (ANSTO)
      • 11:00
        Structural basis for the recognition of nectin adhesion proteins by the Natural Killer cell receptors, TIGIT, CD96 and DNAM-1 15m

        TIGIT, CD96 and DNAM-1 constitute a family of immune receptors that regulate the activity of Natural Killer (NK) cells towards transformed targets. The capacity of these nectin receptors to mediate target cell adhesion, immune synapse formation and regulate effector function is dependent on their recognition of nectin and nectin-like (necl) adhesion molecules, which are over-expressed in a wide variety of cancers. Within this axis, DNAM-1 is a stimulatory receptor that activates NK cell-mediated cytotoxicity and is crirical for tumour immune surveillence, while TIGIT is an inhibitory receptor that counteracts DNAM-1 activity. Whether CD96 functions as an activating or inhibitory receptor is unclear. Here, we have determined the crystal structures of all of the human nectin receptors in complex with their cognate ligands, including TIGIT:nectin-2, CD96:necl-5 and DNAM-1:necl-5. In addition, we have performed a comprehensive binding and mutational analysis of these receptors to fully characterise their ligand binding affinity and specificity. Our findings indicate that TIGIT, CD96 and DNAM-1 recognise their ligands with similar (low-micromolar range) affinity using a conserved docking topology that is reminiscent of that observed for nectin-nectin homo/heterodimer assembly. Structural and mutational analysis highlighted the important role that the ‘lock and key’ motifs within the first extracellular immunoglobulin domain (D1) of each receptor play in ligand binding. Moreover, we demonstrated that the C-C’ loop of TIGIT dictates its ligand binding hierarchy, identified a novel motif in CD96, termed the ‘ancilliary key’, that is critical for necl-5 recognition, and interrogated the role of the second Ig domain of DNAM-1 in necl-5 binding. Altogether, these data significantly broaden our understanding of nectin-nectin receptor interactions and has implications for understanding the molecular basis for tumour recognition and escape.

        Speaker: Dr Richard Berry (Monash University)
      • 11:15
        Protein-Eye View of the in Meso Crystallization Mechanism 15m

        Understanding the behavior of the protein within the nanostructured lipid mesophase is crucial for evolving biological and biomedical applications of hybrid protein-lipid materials. After more than two decades since the invention of the in meso crystallization method for membrane proteins, a protein-eye view of its mechanism is still lacking. Structural studies have suggested that integral membrane proteins partition at localized flat points on the bilayer surface of the cubic phase and that crystal growth occurs from a local fluid lamellar phase conduit. However, studies to date have focused on structural transitions occurring in the lipid mesophase. Here, it was shown using small-angle neutron scattering that the lipid bilayer of monoolein (the most commonly used lipid for biological and biomedical applications) can be contrast-matched using deuteration, allowing isolation of scattering from encapsulated peptides during the crystal growth process for the first time. During in meso crystallization, a clear decrease in form factor scattering intensity of the peptides was observed and directly correlated with crystal growth. A transient fluid lamellar phase was observed, providing direct evidence for the proposed mechanism for this technique. This suggests that the peptide passes through a transition from the cubic phase, via a fluid lamellar phase to the lamellar crystalline phase with similar layered spacing. When high protein loading was possible, the lamellar crystalline phase of the peptide in the single crystals was observed. These findings show the mechanism of in meso crystallization for the first time from the perspective of integral membrane proteins. The used time-of-flight (BILBY) SANS method with contrast-matching opens up the possibility to study hybrid protein-lipid materials for pharmaceutical, food and biological applications.

        Reference: Leonie van 't Hag, Liliana de Campo, Nhiem Tran, Anna Sokolova, Raphael Trenker, Matthew E. Call, Melissa J. Call, Christopher J. Garvey, Anna E. Leung, Tamim A. Darwish, Anwen Krause-Heuer, Robert Knott, Thomas G. Meikle, Calum J. Drummond, Raffaele Mezzenga, and Charlotte E. Conn, Langmuir, 2019, 35(25), 8344-8356.

        Speaker: Leonie van 't Hag (Monash University)
      • 11:30
        Ionising Radiation and Cell Membranes 15m

        Living matter is exposed many forms of radiation from both natural and artificial sources. Broadly speaking these can be classified as either non-Ionising or Ionising, depending on whether the radiation is sufficiently energetic to induce an ionisation event in an atom or molecule. It is recognised that the interaction of ionising radiation (IR) with biological matter can be beneficial, for therapeutic or diagnostic applications, or potentially harmful from uncontrolled or unexpected exposure. IR generates reactive oxygen species via the ionization of water leading to the oxidation of macromolecules such as proteins, DNA and lipids damaging biological systems.1 Gamma radiation is an example of IR and materials can be dosed with high precision at GATRI (ANSTO). For instance, studies have been undertaken on Fibroblast cells irradiated at the GATRI facility (R. M. & G-J. L.) where radiation induced DNA damage and cell death pathways were assessed to determine radiosensitivity. However, to have a better understanding of how cells respond to radiation we would like to determine the impact of radiation on cellular components such as membranes.
        To reduce biological complexity, we have studied simplified systems, the lipids in isolation and membranes containing both lipid and cholesterol. These model cell membranes have been studied as planer films by Neutron Reflectometry and Electrical Impedance Spectroscopy (EIS) and in vesicle form by Small Angle Scattering. The neutron scattering experiments yield structural information while the EIS is an extremely sensitive probe of ion transport across the membrane. These experiments have demonstrated delayed damage onset, as seen in living cells.

        References.
        1. Betlazar, C. et al. Redox Biology 9 (2016): 144–156.

        Speaker: Stephen Holt (Australian Nuclear Science and Technology Organisation)
      • 11:45
        Cytoplasmic accumulation of the Alzheimer’s disease- and ALS-linked RNA-binding protein SFPQ by zinc-induced polymerisation 15m

        SFPQ is an abundant nuclear protein implicated in many aspects of RNA biogenesis. Importantly, nuclear depletion and cytoplasmic accumulation of SFPQ has been linked to neuropathological conditions such as Alzheimer’s disease (AD) and amyotrophic lateral sclerosis (ALS). Here we report the structural basis of cytoplasmic relocation of SFPQ induced by zinc. The crystal structure in complex with zinc reveals the intermolecular interactions of SFPQ mediated by zinc, resulting in infinite polymerisation of SFPQ. As anticipated, the application of zinc to neuronal cells induced cytoplasmic relocation and aggregation of SFPQ. Mutagenesis on the three histidine residues ligating zinc resulted in a significant reduction in zinc-binding affinity in vitro and the zinc-induced cytoplasmic aggregation of SFPQ in neuronal cells. Taken together, we propose that dysregulation of zinc in neuronal cells may represent one potential mechanism that leads to an imbalance in the nucleocytoplasmic distribution of SFPQ, which is emerging as a hallmark of neurodegenerative diseases including AD and ALS.

        Speaker: Dr Mihwa Lee (Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University)
      • 12:00
        Molecular Mechanisms governing αβ T-cell receptor autoreactivity towards CD1b 15m

        Central to both systems of innate and adaptive immunity is the mediation of T-cell recognition of antigen presenting molecules presenting antigens (Ag) by T-cell receptors (TCR). CD1 molecules are Major Histocompatibility Complex (MHC) class I like molecules involved in the presentation of foreign and self-lipid antigens. CD1b exhibits the largest hydrophobic antigen binding cleft, allowing it the capabilities of presenting self and foreign lipids with long carbon tail (up to 80 carbons). While the first molecular mechanism regulating T cell reactivity towards CD1b have been established in the context of mycobacterium tuberculosis infection, the mechanisms surrounding T- cell reactivity towards self-lipid antigens are recently being elucidated. The presentation of self-lipid antigens by CD1b has been established, and includes members of phospholipid, sphingolipid, and ganglioside lipid species. Using tetramer technology with CD1b loaded with targeted self-lipids, a broad repertoire of αβ TCRs have been elucidated, and exhibit discriminatory reactivity between phospholipids and sphingolipids. The crystal structures of CD1b in complex with an αβ TCR (PG90) exhibiting reactivity towards CD1b presenting rare phospholipid, phosphatidylglycerol (PG), and an αβ TCR (BC8B) against a broad repertoire of phospholipids, including phosphatidylcholine (PC), demonstrate differing mechanisms of self-ligand reactivity and recognition. Presentation of both PG and PC by CD1b have implicated roles in cellular stress, autoimmunity, bacterial infection, and anti-tumor properties. These diverse mechanisms of antigen selectivity provide a deeper understanding into their immune cell function in the context of autoimmunity and disease.

        Speaker: Adam Shahine (Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University)
    • 10:45 → 12:25
      Session 15: Nanomaterials and nanotechnology
      • 10:45
        Stiffness and structure in collagen materials 20m

        Collagen is an important component of biological and natural surgical materials. Flexibility and strength are important properties of these materials in use. Here we investigate some factors that control strength and affect flexibility in these materials and the nano-structural changes that affect these properties. The small angle scattering (SAXS/WAXS) beamline at the Australian Synchrotron is used to measure aspects of the structure of collagen in these solid materials including fibril orientation, D-banding (and fibril extension), intermolecular spacing and the change in the helical turn distance. These measurements make full use of the 2D detector. They are combined with mechanical tests for stiffness and strength. Strength is largely due to collagen fibril orientation in the plane of the material, with highly aligned material strongest. Stiffness is affected by changes in humidity or by infusion with 2-propanol or other alcohols. Bend modulus increases logarithmically with increasing 2-propanol concentration in water. Bend modulus decreases with increasing humidity. Intermolecular spacing decreases with 2-propanol and increases with water content and is strongly correlated with stiffness. The change in intermolecular spacing is due to changes in the hydrogen bond structure between tropocollagen molecules causing closer packing of the molecules within a fibril. These may represent general mechanisms for stiffness and strength in many collagen based materials and tissues.

        Speaker: Richard Haverkamp (Massey Univeristy)
      • 11:05
        Tuning the magnetic performance of hexaferrite magnets via nanostructuring 15m

        As modern-day functional materials become more and more complex, an increasingly detailed understanding of the structural features governing their physical properties is necessary in order to understand and improve their macroscopic performance. In the case of permanent magnets, the complex interplay between atomic-, nano- and micro-structural features such as composition, crystallite size, morphology, relative crystallite arrangement, density, etc., determines the magnet’s macroscopic performance. We have developed a bottom-up nanostructuring protocol for preparation of high-performance strontium hexaferrite permanent magnets.[1] Phase pure, highly crystalline SrFe12O19 nanoparticles of various sizes and morphologies have been produced by different synthesis methods and by variation of specific reaction parameters. The tailor-made nanopowders have subsequently been compacted to form highly dense magnets (>90% of the theoretical density) by spark plasma sintering (SPS). Meticulous structural analysis by combined Rietveld refinement of neutron and X-ray powder diffraction data reveal a clear correlation between crystallite size and long-range magnetic order, which, in turn, influences the magnetic properties of the nanocrystallites. Furthermore, the results obtained from Rietveld analysis of powder diffraction data, texture analysis via X-ray and neutron pole figures and magnetic property measurements, reveal a direct correlation between nanoparticle morphology, self-induced texture, crystallite growth during compaction and macroscopic magnetic performance of the consolidated magnets.[2,3] Consequently, magnetically aligned, highly dense magnets with record-high energy product for dry-processed ferrites are obtained by bottom-up nanostructuring means, without application of an external magnetic field before or during compaction.

        [1]. Saura-Múzquiz M., Granados-Miralles C., Stingaciu M., Bojesen E. D., Li Q., Song J., Dong M., Eikeland E. and Christensen M., Nanoscale, 2016, 8, 2857-2866.
        [2]. Eikeland A. Z., Stingaciu M., Mamakhel A. H., Saura-Múzquiz M. and Christensen M., Sci Rep, 2018, 8, 7325.
        [3]. Saura-Múzquiz M., Granados-Miralles C., Andersen H. L., Stingaciu M., Avdeev M. and Christensen M., ACS Appl Nano Mater, 2018, 1, 6938-6949.

        Speaker: Dr Matilde Saura-Múzquiz (University of Sydney)
      • 11:20
        SANS, USANS and rheo-SANS of novel surfactant self-assembly 15m

        SANS has become the standard technique for determination of micelle structure in dilute solutions, offering benefits of contrast variation to interrogate structures with high fidelity. However, the limits of accessible length-scale and dynamic resolution have limited application to some systems of interest, including wormlike micelles and highly concentrated systems. In this talk, we will highlight recent developments and measurements that explore the utility of SANS in combination with USANS and rheology (rheo-SANS) in highly concentrated systems. We primarily focus on the scattering of self-assembled surfactants with additives, from wormlike carbohydrate and betaine systems to highly concentrated lamellar liquid crystals loaded with 2D and 3D nanoparticles. In addition to presenting and discussing data in relation to the chemistry and soft matter physics of the systems explored, we will also discuss modelling developments and future directions required to analyse completely such complex systems.

        Speaker: Rico Tabor (Monash University)
      • 11:35
        Recent development of solid-state microdosimetry for RBE study of ion therapeutic beams and radiation protection of astronauts in space 20m

        Based on many years of experience in development of semiconductor radiation sensors, the Centre for Medical Radiation Physics (CMRP), University of Wollongong in collaboration with ANSTO and SINTEF, has successfully developed a MicroPlus probe for microdosimetry. The probe is based on a Silicon On Insulator (SOI) sensors with 3D micron sized sensitive volumes (SVs) mimicking dimensions of biological cells, known as the “Bridge” and “Mushroom” microdosimeters, Fig 1 shows the MicroPlus probe with the SOI Mushroom microdosimeter.
        The silicon microdosimeters provide extremely high spatial resolution and were used to measure the microdosimetry spectra in different heavy ions fields at Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan and in a proton pencil-beam scanning (PBS) and passive scattering system at different accelerator facilities. Measured microdosimetric parameters were used for derivation of RBE10 using Microdosimetric Kinetic Model (MKM). Derived RBE10 values in response to 290 MeV/u carbon-ions SOBP is presented in Fig. 2. The RBE10 values obtained with the SOI microdosimeters match very well with those obtained from the TEPC measurements. Due to the high spatial resolution of the microdosimeter, a more detailed RBE10 distribution was obtained at the end of the SOBP compared to the TEPC.
        Fig. 3 shows the comparison of the Geant4 simulated and microdosimetric measurement based RBE10 for the 400 MeV/u 16O beam in water. Due to submilimetre spatial resolution, it was possible to see that the peak of physical dose does not coincide with the maximum RBE10.
        The developed SOI microdosimeters can be very useful for dose equivalent measurements in Solar Particle Events (SPE) and Galactic Cosmic Rays (GCR) mixed radiation fields for radiation protection of astronauts and evaluation of radiation shielding. Recently an experiment with different thicknesses of Al alloy to mimic the ISS wall was carried out in 500 MeV/u Fe ions field at HIMAC to determine the quality factor, Q ̅ and the dose equivalent, Hp(10) per incident ion cm-2 at different depths in a phanotm downstream of the Al wall. Fig 4 shows the microdosimetric spectra and corresponding to them Q ̅ for different scenarios.

        This work presented an application of SOI microdosimeters for RBE evaluation in heavy ion therapy and for Q ̅ and H determination in mimicking GCR radiation environment that can be used for radiation shielding optimization and radiation protection in space.

        Speaker: Prof. Anatoly Rozenfeld (University of Wollongong)
    • 10:45 → 12:15
      Session 16: Spectroscopy
      • 10:45
        Adventures in Iron Biochemistry: X-ray Spectroscopy as a Tool for Studying Biological Iron Coordination Chemistry 15m

        Transition metals like iron (and copper) are catalytic biological cofactors of fundamental importance. The over abundance of potential ligands in biological fluids limits the fraction of solvated metal ions to vanishingly lower levels means coordination chemistry determines the reactivity and availability of biometals across cellular environments. Coordination chemistry is dynamic, responding to the pH, redox potential and concentration of ligands and metals. Traditionally, characterisation of specific metal-ligand species requires isolation of the complex, necessitating disruption of biological systems despite the attendant risk of mismetallation and loss of biochemical context. Despite the confounding potential of typical preparation methodologies, the tools available to study biological coordination chemistry in situ have remained limited. The synergy of synchrotron-based X-ray fluorescence microscopy (XFM) and X-ray absorption near edge structure (XANES) spectroscopy represents a powerful analytical approach for studying iron (and copper) biochemistry of individual cells within intact organisms. This permits quantitative mapping of metal distribution and profiling of the native coordination environment without the need for exogenous molecular probes.

        We demonstrate the development of non-destructive XANES imaging, to study copper and iron speciation within cultured cells and the simple multi-cellular model organism Caenorhabditis elegans respectively. Further we utilise this technique to explore the changes in iron metabolism that accompany ageing and models of human disease in C. elegans showing how and where iron homeostasis is lost. This work has demanded particularly careful monitoring of the imaging dose associated with the measurement to avoid photoreduction in conjunction with monitoring of the sample environment to ensure data are representative of the native metalloarchitecture. While work is ongoing, we will highlight the potential applications of XANES imaging in biology and propose some heuristics that can safeguard against the introduction of measurement artefacts.

        Speaker: Dr Simon James (ANSTO)
      • 11:00
        The Thermal Triple-Axis and Filter Spectrometers on TAIPAN 15m

        The thermal triple-axis spectrometer on TAIPAN has been running for over ten years and together with the filter spectrometer which has been running for three and half years have contributed to a variety of studies in solid-state physics and chemistry, materials science and engineering, geosciences, energy science, and the biosciences. In particular a strong focus has been elucidating the magnetism in highly ordered thin film multilayers, heterostuctures, and superlattices, as well as studying low lying excitations such as in high $T_{c}$ superconductor materials. The so-called Beryllium filter spectrometer, on the other hand, has been to date used predominately on powdered hydrogenous material. Hydrogen has a large isotropic incoherent scattering cross-section which allows for local molecular vibrations and structure to be directly probed. The mechanics of interaction between molecular units is studied through the analysis of the vibrational spectra which is achieved through a knowledge of the structure of each material, symmetry arguments that may be obtained via group theoretical analysis, and of course through calculation, such as force field arguments and calculations, and ab-initio approaches. Here the two spectrometers are briefly described giving an overview of their capabilities. Five pieces of current scientific work are also given as good examples showing the capability and type of work done on TAIPAN. These are magnetism in strained magnetic thin films, low energy excitations in strongly correlated materials, lanthanide zirconates as model nuclear containment materials, hydrogen in steels, and aminoboranes.

        Speaker: Anton Stampfl (Australian Nuclear Science and Technology Organisation)
      • 11:15
        Characterisation of Na+ dynamics in γ-Na3-2xMgxPO4 15m

        Solid-state ionic conductors have been increasingly investigated as an alternative to liquid electrolytes in solid state sodium ion batteries. Whilst much progress has been made in the design and development of promising candidate materials, their complex structures and difficulties in probing dynamics beyond the bulk picture has meant that understanding the mechanisms involved in Na+ diffusion remains a challenge. Quasi-elastic neutron spectroscopy (QENS) is one avenue which provides an opportunity to gain insight into these mechanisms at the atomic level.

        This work focuses on characterising sodium-ion self-diffusion using QENS in Mg2+ stabilised γ-Na3PO4. From a dynamics perspective, γ-Na3PO4 is of interest since its structure features multiple inequivalent sodium sites, forming non-Bravais sublattices.[1] Since it cannot be known a priori which site(s) are involved in the diffusion, the standard approach[2] which is used to model the QENS dynamic scattering function S(Q, ω) in similar systems does not generally describe the diffusion mechanisms at play. Consequently, we have modelled the S(Q, ω) through the construction of a matrix to account for all possible jumps within the material by solving the corresponding eigenvalue problem.[3,4] Here, we present the insight that this approach provides on details of the possible Na+ diffusion mechanisms, including diffusion paths and relaxation times.

        [1] D. Wilmer and J. Combet, Chemical Physics 292 (2), 143-152 (2003).
        [2] C. T. Chudley and R. J. Elliott, Proceedings of the Physical Society 77 (2), 353 (1961).
        [3] J. M. Rowe, K. Sköld, H. E. Flotow and J. J. Rush, Journal of Physics and Chemistry of Solids 32 (1), 41-54 (1971).
        [4] O. G. Randl, B. Sepiol, G. Vogl, R. Feldwisch and K. Schroeder, Physical Review B 49 (13), 8768-8773 (1994).

        Speaker: Emily Cheung (University of New South Wales)
      • 11:30
        Ultrahigh-resolution neutron spectroscopy of low-energy spin dynamics in UGe$_2$ 15m

        Studying the prototypical ferromagnetic superconductor UGe$_2$ we demonstrate the potential of the newly developed longitudinal modulated intensity by zero effort (MIEZE) technique for the study of quantum matter. MIEZE is a novel neutron spectroscopy method with ultrahigh energy resolution of at least 1$\mu$eV at the RESEDA beamline at the Heinz Maier-Leibnitz Zentrum in Garching, Germany. Unlike other spin echo techniques, MIEZE encodes the resolution via a modulation of the neutron beam intensity and is insensitive to depolarization at the sample position and can even be combined with magnetic fields. Further, by performing the experiment in small angle neutron scattering (SANS) geometry, this simultaneously allowed us to resolve momentum transfers down to 0.015 Å$^{-1}$. In the case of UGe$_2$, we reveal purely longitudinal spin fluctuations with a dual nature arising from 5$f$ electrons that are hybridized with the conduction electrons. Local spin fluctuations are perfectly described by the Ising universality class in three dimensions, whereas itinerant spin fluctuations occur over length scales comparable to the superconducting coherence length, showing that MIEZE is able to spectroscopically disentangle the complex low-energy behavior characteristic of quantum materials.
        [1] F. Haslbeck, et al., Phys. Rev. B 99 014429 (2019)

        Speaker: Mr Franz X. Haslbeck (Physics Department, Technical University of Munich, Germany; Institute for Advanced Study, Technical University of Munich, Germany)
    • 12:25 → 13:30
      Lunch 1h 5m
    • 13:30 → 14:30
      Session 19: Spectroscopy (Part 2)
      • 13:30
        Combining Far-IR from beneath and UV-Vis from above to follow de-oxygenation and re-oxygenation of haemoglobin in blood. 15m

        An Ocean Optics ISP-REF Integrating Sphere connected to USB4000 XRI spectrophotometer and Spectrasuite software was placed centrally above the diamond window of a GladiATR Single Reflection Attenuated Total Reflection (ATR) Accessory on the Far-IR/THz Bruker IFS125HR FTIR spectrometer with OPUS software. By placing a drop of blood on the out-of-vacuum ATR window then positioning the small Integrating Sphere, connected to a micro-spectrophotometer, the conversion of oxy-haemoglobin to deoxy-haemoglobin and reverse can be followed by observing both spectra. Oxy-haemoglobin has characteristic absorption peaks at 540 nm and 575 nm whereas, in deoxy-haemoglobin these are replaced by a single peak at 555 nm. By enclosing the combined spectrometers in a ‘tent’ of clear plastic that is sealed around the edge and connected to a gas flow inlet and an electric air-pump the atmosphere experienced by the blood can be altered. Initially, the Far-IR spectra is dominated by water in the blood, but when dry air is blown through the bag the water peaks decrease and the Far-IR spectrum of oxy-haemoglobin in blood is obtained. Pumping out the air in the tent aids the removal of water. Once a stable spectrum is obtained the tent can be filled with nitrogen and the transition of oxy-haemoglobin to deoxy-haemoglobin followed by the UV-Vis spectrometer. The Far-IR spectra is also observed to change. Once both spectra have stabilized the Far-IR and UV-Vis spectra can be recorded. To reverse the reaction the blood is wetted with water and air is readmitted into the tent and the conversion back to oxy-haemoglobin is followed by UV-Vis. In this way we can be sure that the spectrum we are measuring by Far-IR is in fact from deoxy-haemoglobin or oxy-haemoglobin or, in the transition stage, by a changing ratio of oxy and deoxy-haemoglobin. This process can be repeated for several cycles.
        The interconversion of oxy-haemoglobin and deoxy-haemoglobin is relevant to the state of blood in cadavers during autopsy. When a person died they stop getting oxygen to their blood and the oxy-haemoglobin can loose oxygen to become deoxy-haemoglobin. However, when chilled in a mortuary fridge the cold blood has a higher affinity for oxygen and the authors [1] have shown that oxygen can be absorbed through the skin after death - unless there is a barrier such as a plaster on the skin or the skin is encased in plastic or some other impermeable material. So the oxygenated state of the blood at autopsy is a consequence of the temperature and stage of reoxygenation.
        This innovation enabled the interconversion of these crucial blood components to be studied. Although this innovation has only been used for this specific investigation, that lends itself to coupling Far-IR with UV-Vis, it shows that other ranges of spectrometry could be undertaken in tandem on the ATR Far-IR at the Australian Synchrotron to investigate conversions.
        [1] Watchman, H.M., Walker, G.S., Randeberg, L.L., & Langlois, N.E., 2011. Re-oxygenation of post-mortem lividity by passive diffusion through the skin at low temperature”, Forensic Science, Medicine, and Pathology, 7(4), 333-335.

        Speaker: Dr Stewart Walker (School of Chemical and Physical Sciences, Flinders University)
      • 13:45
        Inelastic Neutron Scatterings Reveal Mechanism for Barocaloric Effects in Plastic Crystals 15m

        Refrigeration is of vital importance for modern society—for example, for food storage and air conditioning—and 25 to 30 per cent of the world’s electricity is consumed for refrigeration. Current refrigeration technology, mostly involving the conventional vapour compression cycle, is of growing environmental concern because of large amount of greenhouse gases released into atmosphere every year. As a promising alternative, refrigeration technologies based on solid-state caloric effects have been attracting attention for several decades. However, their application is restricted by the limited performance of current caloric materials, owing to small isothermal entropy changes and large external driving fields. Recently, it has been discovered that a class of disordered solids called plastic crystals can deliver colossal barocaloric effects (CBCEs) (large cooling effects induced by pressure). In this presentation, I will report how inelastic neutron scattering and quasi-elastic neutron scattering, performed on Pelican instrument, can help in understanding the mechanism responsible for the excellent cooling effects of the plastic crystals [1].

        [1] Bing Li, et al. Colossal barocaloric effects in plastic crystals, Nature, https://doi.org/10.1038/s41586-019-1042-5

        Speaker: Dehong Yu (Australian Nuclear Science and Technology Organisation)
      • 14:00
        Toward the phase analog of XAFS 15m

        XAFS in absorption and fluorescent modes has been one of the most commonly used techniques in a wide range of scientific research and applications. Current applications of XAFS to low absorbing samples such as ultra-thin films in semiconductors and nano-devices have been limited. As the real component of the complex refractive index (phase) is generally several orders of magnitude larger than the imaginary component (absorption) in the x-ray regime, X-ray phase fine structure is expected to be more sensitive in differentiating chemical states. In addition, X-ray phase fine structure provides extra information which is complementary to those obtained by conventional XAFS including coherent scattering processes undergoing within the sample. X-ray phase fine structure therefore opens great opportunities for extending XAFS research into a new dimension. We will present both phase and absorption fine structures of a copper sample obtained simultaneously at the XFM beamline (Australian Synchrotron) by applying the HERALDO imaging technique across the copper K-edge. The results provide a critical experimental benchmark for further theoretical development and has potential to delve into the phase equivalent of the XAFS technique.

        Speaker: Dr Chanh Tran (LIMS, School of Molecular Sciences, La Trobe University)
      • 14:15
        The MEX beamlines at the Australian Synchrotron 15m

        The Medium Energy X-Ray Absorption Spectroscopy Beamlines at ANSTO’s Australian Synchrotron will be a suit of beamlines particularly optimised to facilitate new scientific opportunities in human health and biology; food, agriculture, and plants; advanced materials, catalysis, and chemistry; and environment, Earth, and minerals. They will offer routine high quality X-ray Absorption Spectroscopy characterization of elements Si and upwards (1.7 – 13.6 keV), also with the latest developments in high energy resolution spectroscopies and providing spectroscopic quality data with a small spot (2 micron) for S to Se.

        The beamlines are well into the design and procurement stage, on track to begin construction in 2020 and user operations in 2021. A review of the design, status and scientific possibilities will be presented

        Speaker: Chris Glover (Australian Synchrotron)
    • 13:30 → 15:10
      Session 20: Imaging
      • 13:30
        Visible and hidden paintings: Bronzino’s Cosimo I de’Medici in armour 1540s. 20m

        The Art Gallery of NSW’s Portrait of Cosimo I de Medici, emerged from obscurity in 1971 and is considered to be a ¾ length version of an earlier ½ length composition in the Uffizi Gallery in Florence (Simon 1983). An X-ray image was published in 1987 (Simon) showing that another portrait of a man in a wide brimmed hat holding a book exists underneath the painting.

        Since the 1980s, many more works by Agnolo Bronzino have been studied with technical photography, infrared and X-rays and we now have a greater understanding of the artist’s extraordinary tendency to re-work and radically modify his paintings directly on the panels (Plazzotta & Keith 1999, Tucker 1985).

        Early this year the Sydney painting underwent X-ray fluorescence mapping at the Australian Synchrotron to enable detailed examination of its elemental composition and to enhance the imaging of the lower painting. The elemental mapping of the painting was done at a resolution of 120 microns enabling the construction of elemental distribution maps across the whole work which can be assigned to the artist’s use of different mineral pigments. The distribution and application of each type of pigment visualised in the maps demonstrate that the evolution of the painting in the artist’s studio was a complex sequence of alterations and adjustments of subject, size and composition.

        REFERENCES:
        Plazzotta, Carol & Larry Keith, ‘Bronzino’s ‘Allegory’: new evidence of the artist’s revisions’, The Burlington Magazine, vol.141, no. 1151, Feb 1999, pp. 89-99.
        Simon, Robert B. ‘Bronzino’s portrait of Cosimo I in armour’, The Burlington Magazine, vol. 125, no 966, Sep 1983, pp 527-39.
        Simon, Robert B. ‘’Blessed by the hand of Bronzino”: the portrait of Cosimo I in armour’, The Burlington Magazine, vol. 129, no 1011, Jun 1987, pp 387-88.
        Tucker, Mark S. ‘Discoveries made during the treatment of Bronzino’s Cosimo I de’Medici as Orpheus’, Philadelphia Museum of Art Bulletin, vol. 81, no. 348, Autumn 1985, pp. 28-32.

        Speaker: Dr Paula Dedge (Art Gallery NSW )
      • 13:50
        Dynamic transformations of drug delivery systems by proteins: when equilibrium studies are not enough. 20m

        Lipid-based drug delivery systems have great potential in biomedical applications. They comprise of the self-assembly of biocompatible lipids, where the structures they form dictates the rate of release of drug. However, their potential has been limited by an incomplete understanding of their fate in vivo. The presented research gives insight into the response of lipidic membranes to exposure to different proteins: liposomes with phospholipase C and cubosomes in physiologically mimetic media. What was observed in dynamic studies was not what was predicted by equilibrium experiments, highlighting the need to understand physiological processes in real time. Synchrotron SAXS was key to observing these interactions. Understanding the type and timing of phase transitions in these lipid based drug delivery systems will better direct their design for biomedical applications.

        Speaker: Dr Khay Fong (Newcastle University)
      • 14:10
        Neutron Micro-Computed Tomography: A Revolution in Non-Destructive Paleontology 15m

        The physical extraction of fossilised remains from rocks enables quantitative physiological investigation of bone-dimensions, volume, and porosity, however leads to the destruction of valuable contextual information and soft-tissue remains within the matrix.

        Conventional and synchrotron-based X-ray computed tomography (XCT) have been utilised for many years as critical tools in uncovering valuable 3-D internal and surface renderings of scientifically important fossils, however poor contrast and X-ray penetration often prevents thorough tomographic analysis. DINGO, Australia’s neutron micro-computed tomography (nCT) instrument, located at the OPAL nuclear research reactor, is being used to obtain unpreceded renderings of extraordinary fossilised anatomical features not visible with conventional imaging techniques. Drawing upon specimens scanned from across Australia, North America, New Zealand, and China, this presentation will demonstrate DINGO’s capabilities and the complementarity of nCT to classic XCT methods for certain geological formations and fossil localities.

        A selection of nCT case studies to be presented:

        • nCT studies conducted on a Jurassic cynodont, one of the earliest and
          most primitive ancestors to all living mammals, revealing exceptional
          conservation of internal bone structure of the cranium, teeth and
          internal tissues; features that are not visibly rendered by XCT, nor
          phase-propagation synchrotron XCT methods.
        • The illumination of “corrective procedures” in paleontological
          specimens
        • Uncovering the morphology and internal anatomy of fire-adapted
          mid-Cretaceous south polar conifers
        • Applicability of nCT to the Richards Spur locality,Oklahoma, USA.
        • Stomach contents of dinosaurs and early birds.
        Speaker: Joseph Bevitt (ANSTO)
      • 14:25
        Present and Future Neutron Imaging Applications on DINGO at OPAL 15m

        The neutron imaging instrument DINGO is operational since October 2014 to support research at ANSTO. DINGO had a high subscription rate from a broad national and international scientific user community and for routine quality control for defense, industrial, cultural heritage and archaeology applications. DINGO provides a useful tool to give a different insight into objects because of different contrast compared to X-rays and high sensitivity to light elements. In the field of industrial application it has shown promising results for studying cracking and defects in concrete or other structural material. A major part of applications from both sides of the community, research and industrial user, was demanding the high resolution setup on DINGO and asking for an upgrade to achieve resolution below 25µm pixel size.
        In the original design DINGO could provide a minimum pixel size of 27 µm. The neutron beam size can be adjusted to the sample size from 50 x 50 mm$^2$ to 200 x 200 mm$^2$ with a resulting pixel size from 27µm to ~100µm. Depending on the sample composition a full tomography has been taken in 24 – 36 hours with a 50 µm thin ZnS/6LiF-screnn and the CCD (Andor IKON-L) camera. In a two stage upgrade the background radiation has been reduce by an additional slit system adjusting the beam size more flexible and further down to 0.5 x 0.5 mm$^2$. The new system allows minimizing the beam according to the sample size. In combination with the Andor IKON SCMOS and Kenko distance rings, to increase the focal length of the existing 100mm lens the pixel size was reduced to 7µm. The scintillator was a 10 µm thick Gadox screen and for each projection we have taken 3 – 6 images for better white spot correction. We would like to present first radiography and tomography results using the new setup. A full tomography under these conditions can be taken in 2 -4 days depending on the nature on the sample.
        In addition we have now a slit system installed to adjust the beam size even further to each individual sample. This new slit system reduces noise in form of white spots in the high resolution setup with small pixel size from 5- 20 µm by up to 70%. An overall range of pixel size from 5µm to ~100µm can be achieved now. The whole instrument operates in two different positions, one for high resolution and one for high speed.
        We will show the performance of new the CMOS camera IRIS 15 with a 2960 x 5060 pixels chip and a physical pixel size of 4.5 µm. In combination with new scintillation screens like Gadox/LiF mixed screen it enables DINGO to run neutron tomography experiments with 5-10 µm resolution on large samples in a reasonable time of 24 -48 hours.

        Speaker: Dr Ulf Garbe (ANSTO)
      • 14:40
        Neutron Super Resolution Ghost Imaging 15m

        The concept of ghost imaging emerged from visible-light optics a little over two decades ago. Since then, its use has spread to x-ray, electron and atom optics. However, the method appears never to have been reported for neutron optics.

        In a nutshell, ghost imaging enables spatial resolution multiplexing of a detector by patterning the illumination beam. Typical ghost imaging protocols are used to achieve spatial resolution using a single pixel detector. More generally however, one can use ghost imaging to increase the resolution of a pixellated detector, i.e. achieving super-resolution imaging.

        In this work we present a proof of concept for a parallelised form of neutron ghost imaging that enables us to increase the resolution of a pixellated neutron-imaging detector.

        Our method for neutron super-resolution ghost imaging works as follows. A spatially random mask is used, that has an intensity transmission function that has been previously measured as a function of transverse coordinates, to a specified resolution. This specified resolution, to which the mask transmission function has been measured, is higher than the resolution of a given position-sensitive detector. The random mask and low resolution position-sensitive detector can then be employed in tandem, with each pixel of the low-resolution detector working as an independent bucket detector in the ghost-imaging sense of the term. We can then take a series of low-resolution neutron images of an unknown object, with the mask in a different known transverse position for the detection of each low-resolution image. From these data we then show how a parallel form of ghost imaging protocol -- similar to that which we previously developed in the x-ray domain -- may be employed to obtain a neutron-optical image with significantly higher resolution than each of the low-resolution images that were taken.

        Our proof-of-concept experiment, on neutron super-resolution ghost imaging, was performed using thermal neutrons at the DINGO instrument of the Australian Centre for Neutron Scattering. Our results show how the addition of single spatially random mask can turn a crude 4 x 4 pixel detector into a 128 x 128 pixel position-sensitive detector. This is both the first example of neutron ghost imaging, and a tangible example of the practical utility of ghost imaging in a neutron-optics context.

        Speaker: Andrew Kingston (Australian National University)
      • 14:55
        Ion beam microscopy in serve of material investigations 15m

        High-energy ion microscopes attached to an ion accelerator system are highly versatile research instruments for applications in high-resolution material investigations capable of precise tuning for a given sample or task. Their design and flexibility is usually closely related to properties of the accelerator system. We used a suite of ion nanobeams (proton, alpha, carbon and oxygen ions) with magnetic rigidity (ME/q2) value up to 40 MeV amu/e2 provided by the high-energy ion microscope of accelerator facility at ANSTO for here presented material investigation studies of micron-sized sample structures or micron-sized particles from very different origins. Examples include bio systems, health, electronics, manufacturing and cultural heritage.
        Keywords: material, structure, microscopy, ion nanobeam
        *Corresponding author: zkp@ansto.gov.au

        Speaker: Zeljko Pastuovic (Centre for Accelerator Science of ANSTO)
    • 14:30 → 15:00
      Session 21: Emergent Physics
      • 14:30
        FeMn$_3$Ge$_2$Sn$_7$O$_{16}$ : a Spin-liquid Candidate with a Perfectly Isotropic 2-D Kagomé Lattice 15m

        The compound Fe$_4$Si$_2$Sn$_7$O$_{16}$ has a hitherto unique crystal structure, consisting of ionic oxide layers based on edge-sharing FeO$_6$ and Sn$^{4+}$O$_6$ octahedra alternating with layers of intermetallic character based on FeSn$^{2+}_6$ octahedra, separated by covalent SiO$_4$ tetrahedra. The ionic layers contain kagomé lattices of magnetic Fe$^{2+}$ cations (octahedral crystal field, high-spin [HS] d$^6$, $S = 2$) with perfect trigonal symmetry; while the intermetallic layers are non-magnetic because the Fe$^{2+}$ is in the low-spin ($S = 0$) state. The formula is more correctly written as Fe$_4$Si$_2$Sn$_7$O$_{16}$ to differentiate the one LS-Fe$^{2+}$ per formula unit in the intermetallic layer from the three HS-Fe$^{2+}$ per formula unit in the kagomé oxide layer.

        Fe$_4$Si$_2$Sn$_7$O$_{16}$ also has a unique magnetic ground state below a Néel ordering temperature T$_N$ = 3.5 K, in which the spins on 2/3 of the Fe$^{2+}$ sites in the kagomé oxide layers order antiferromagnetically, while 1/3 remain disordered and fluctuating down to at least 0.1 K. The nature and origin of this unique “striped” partial spin-liquid state is unclear. The fact that it breaks trigonal symmetry, which the more conventional q = 0 or √3×√3 kagomé states would not, raises the possibility that the anisotropic distribution of the 6 unpaired spins on HS-Fe$^{2+}$ (t$_{2g}^4$e$_g^2$) plays a role. To test this possibility, we have now synthesised an isotropic analogue with a kagomé lattice of HS Mn$^{2+}$ (t$_{2g}^3$e$_g^2$), by co-substituting Ge$^{4+}$ for Si$^{4+}$ in the bridging/stannite layers to match the lattice dimensions between layers.

        We found that FeMn$_3$Ge$_2$Sn$_7$O$_{16}$ has the same "striped" magnetic ground state as Fe$_4$Si$_2$Sn$_7$O$_{16}$, in the same temperature range, ruling out this explanation. However, the zero-field striped structure is collinear for FeMn$_3$Ge$_2$Sn$_7$O$_{16}$ vs. non-collinear for Fe$_4$Si$_2$Sn$_7$O$_{16}$, which may indeed be a consequence of the change in anisotropy on the magnetic kagomé site, and suggests that FeMn3Ge2Sn7O16 is an even more ideal spin-liquid candidate than Fe$_4$Si$_2$Sn$_7$O$_{16}$. We also found that an external applied magnetic field lifts the degeneracy on the disordered site, giving rise to another ordered magnetic structure never before observed nor predicted on a kagomé lattice.

        Speaker: Chris Ling (University of Sydney)
      • 14:45
        Patterning topological insulators using ion beams 15m

        The surfaces of Sb2Te3 topological insulator crystals were implanted using a 40 keV chromium ion beam at the Centre for Accelerator Science, ANSTO. The resulting chemical structure was studied using atomic-resolution transmission electron microscopy and soft X-ray absorption spectroscopy. A thin magnetic crystalline region is formed near the surface. A uniform valence state of Cr3+ is detected, with no evidence of metallic clustering. Superparamagnetic behaviour was detected up to 300 K.

        Speakers: Dr Cortie David (University of Wollongong), Zeljko Pastuovic (Centre for Accelerator Science of ANSTO)
    • 15:10 → 15:30
      Afternoon Tea 20m
    • 15:30 → 16:00
      Closing Remarks
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