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A facility for performing serial crystallography measurements has been developed at the Australian synchrotron. This facility incorporates a purpose built high viscous injector, Lipidico, as part of the macromolecular crystallography (MX2) beamline to measure large numbers of small crystals at room temperature. The goal of this technique is to enable crystals to be grown/transferred to glass syringes to be used directly in the injector for serial crystallography data collection. The advantages of this injector include the ability to respond rapidly to changes in the flow rate without interruption of the stream. Several limitations for this high viscosity injector (HVI) exist which include a restriction on the allowed sample viscosities to >10 Pa.s. Stream stability can also potentially be an issue depending on the specific properties of the sample. A detailed protocol for how to set up samples and operate the injector for serial crystallography measurements at the Australian synchrotron is presented here. The method demonstrates preparation of the sample, including the transfer of lysozyme crystals into a high viscous media (silicone grease), and the operation of the injector for data collection at MX2.

The Imaging and Medical Beamline (IMBL) is a superconducting multipole wiggler-based beamline at the 3 GeV Australian Synchrotron operated by the Australian Nuclear Science and Technology Organisation (ANSTO). The beamline delivers hard X-rays in the 25–120 keV energy range and offers the potential for a range of biomedical X-ray applications, including radiotherapy and medical imaging experiments. One of the imaging modalities available at IMBL is propagation-based X-ray phase-contrast computed tomography (PCT). PCT produces superior results when imaging low-density materials such as soft tissue (e.g., breast mastectomies) and has the potential to be developed into a valuable medical imaging tool. We anticipate that PCT will be utilized for medical breast imaging in the near future with the advantage that it could provide better contrast than conventional X-ray absorption imaging. The unique properties of synchrotron X-ray sources such as high coherence, energy tunability, and high brightness are particularly well-suited for generating PCT data using very short exposure times on the order of less than 1 min. The coherence of synchrotron radiation allows for phase-contrast imaging with superior sensitivity to small differences in soft-tissue density. Here we also compare the results of PCT using two different detectors, as these unique source characteristics need to be complemented with a highly efficient detector. Moreover, the application of phase retrieval for PCT image reconstruction enables the use of noisier images, potentially significantly reducing the total dose received by patients during acquisition. This work is part of ongoing research into innovative tomographic methods aimed at the introduction of 3D X-ray medical imaging at the IMBL to improve the detection and diagnosis of breast cancer. Major progress in this area at the IMBL includes the characterization of a large number of mastectomy samples, both normal and cancerous, which have been scanned at clinically acceptable radiation dose levels and evaluated by expert radiologists with respect to both image quality and cancer diagnosis. [ABSTRACT FROM AUTHOR]

NiO/Ni thin film bilayers have been grown on Si (100) substrates using low temperature dc reactive magnetron sputtering. The samples were grown under identical process conditions but with different amounts of NiO deposited in order to determine film quality as a function of thickness. In order to investigate the structural properties of the NiO overlayers a synchrotron detector has been developed to make energy-resolved electron yield x-ray absorption spectroscopy measurements at ambient pressure. From these studies we have been able to construct a complete depth profile of the NiO/Ni bilayers and, by modeling of the electron multiplication/propagation processes within the films, extract quantitative information about them. In combination with atomic force microscopy measurements we have determined that there exists a clear variation in the structural and morphological properties of the NiO thin films as a function of thickness. The densest overlayers with the most conformal surface are observed for film thicknesses <20 nm and >100 nm. We rationalize these results in terms of the underlying morphology of the Ni film and the effects of misfit strain between the layers. [ABSTRACT FROM AUTHOR]

The recent development of serial crystallography at synchrotron and X-ray free-electron laser (XFEL) sources is producing crystallographic datasets of ever increasing volume. The size of these datasets is such that fast and efficient analysis presents a range of challenges that have to be overcome to enable real-time data analysis, which is essential for the effective management of XFEL experiments. Among the blocks which constitute the analysis pipeline, one major bottleneck is `peak finding', whose goal is to identify the Bragg peaks within (often) noisy diffraction patterns. Development of faster and more reliable peak-finding algorithms will allow for efficient processing and storage of the incoming data, as well as the optimal use of diffraction data for structure determination. This paper addresses the problem of peak finding and, by extension, `hit finding' in crystallographic XFEL datasets, by exploiting recent developments in robust statistical analysis. The approach described here involves two basic steps: (1) the identification of pixels which contain potential peaks and (2) modeling of the local background in the vicinity of these potential peaks. The presented framework can be generalized to include both complex background models and alternative models for the Bragg peaks. [ABSTRACT FROM AUTHOR]

High-resolution X-ray imaging techniques using optical elements such as zone plates are widely used for viewing the internal structure of samples in exquisite detail. The resolution attainable is ultimately limited by the manufacturing tolerances for the optics. Combining ideas from crystallography and holography, this limit may be surpassed by the method of coherent diffractive imaging (CDI). Although CDI shows particular promise in applications involving X-ray free-electron lasers, it is also emerging as an important new technique for imaging at third-generation synchrotrons. The limited coherent output of these sources, however, is a significant barrier to obtaining shorter exposure times. A fundamental assumption of coherent diffractive imaging is that the incident light is well-approximated by a single optical frequency. In this Letter, we demonstrate the first experimental realization of 'polyCDI', using a broadband source to achieve a factor of 60 reduction in the exposure time over quasi-monochromatic coherent diffractive imaging. [ABSTRACT FROM AUTHOR]

Laue diffraction, energy scanning and reciprocal space mapping are three micro-beam synchrotron X-ray diffraction techniques allowing the investigation of local misorientation induced by the dislocation substructure. In this paper a comparison between the three methods is presented, based on the mapping of a single 311 reflection from a grain within a Ni polycrystal specimen deformed to a tensile plastic strain of ~9%. Qualitatively it is observed that the maps obtained by different techniques all share the same features, although some deviations exist due to experimental limitations associated with each of the measurement techniques. [ABSTRACT FROM AUTHOR]

The availability of third-generation synchrotrons and ultimately X-ray free-electron lasers is driving the development of many new methods of microscopy. Among these techniques, coherent diffractive imaging (CDI) is one of the most promising, offering nanometre-scale imaging of non-crystallographic samples. Image reconstruction from a single diffraction pattern has hitherto been possible only for small, isolated samples, presenting a fundamental limitation on the CDI method. Here we report on a form of imaging we term ‘keyhole’ CDI, which can reconstruct objects of arbitrary size. We demonstrate the technique using visible light and X-rays, with the latter producing images of part of an extended object with a detector-limited resolution of better than 20 nm. Combining the improved resolution of modern X-ray optics with the wavelength-limited resolution of CDI, the method paves the way for detailed imaging of a single quantum dot or of a small virus within a complex host environment. [ABSTRACT FROM AUTHOR]

Serial Synchrotron Crystallography (SSX) is rapidly emerging as a promising technique for collecting data for time-resolved structural studies or for performing room temperature micro-crystallography measurements using micro-focused beamlines. SSX is often performed using high frame rate detectors in combination with continuous sample scanning or high-viscosity or liquid jet injectors. When performed using ultra-bright X-ray Free Electron Laser (XFEL) sources serial crystallography typically involves a process known as 'diffract-and-destroy' where each crystal is measured just once before it is destroyed by the intense XFEL pulse. In SSX, however, particularly when using high-viscosity injectors (HVIs) such as Lipidico, the crystal can be intercepted multiple times by the X-ray beam prior to exiting the interaction region. This has a number of important consequences for SSX including whether these multiple-hits can be incorporated into the data analysis or whether they need to be excluded due to the potential impact of radiation damage. Here, we investigate the occurrence and characteristics of multiple hits on single crystals using SSX with lipidico. SSX data are collected from crystals as they tumble within a high viscous stream of silicone grease flowing through a micro-focused X-ray beam. We confirmed that, using the Eiger 16M, we are able to collect up to 42 frames of data from the same single crystal prior to it leaving the X-ray interaction region. The frequency and occurrence of multiple hits may be controlled by varying the sample flow rate and X-ray beam size. Calculations of the absorbed dose confirm that these crystals are likely to undergo radiation damage but that nonetheless incorporating multiple hits into damage-free data should lead to a significant reduction in the number of crystals required for structural analysis when compared to just looking at a single diffraction pattern from each crystal. [ABSTRACT FROM AUTHOR]

Abstract: Better understanding of the distribution of elastic and plastic strains in deformed polycrystalline, multiphase materials is important for structural engineering. The deformation response depends upon the interaction of grains of different orientations, and the anisotropy associated with each phase. Strain partitioning and tensile-compressive hardening asymmetry arises due to mismatches in modulus and ductility between grains and phases in alloys such as Ti–6Al–4V that displays both strong anisotropy within one phase and significant differences of properties between phases. Simple four-point bent beam samples were studied using the newly available energy-dispersive X-ray diffraction setup at the high energy white-beam synchrotron beamline I12 (JEEP) at Diamond Light Source. Diffraction patterns from the bent polycrystalline Ti6Al4V samples were collected using the new 23-cell “horseshoe” detector and interpreted using Pawley refinement to extract unit cell parameters, thus allowing elastic strain to be determined. The tensile-compressive hardening asymmetry was quantified for the grains oriented with the basal plane perpendicular to the loading direction. Initial evaluation of the performance of the new instrument is reported. [Copyright &y& Elsevier]