This PDF file contains the front matter associated with SPIE Proceedings Volume 9592 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

The hard X-ray nanoprobe at Taiwan Photon Source (TPS) makes use of the large numerical aperture obtained by nested Montel mirrors. To fully uptake the focusing power and flux, these mirrors requires the surface slope error no less than 0.05 μrad and are symmetrically placed with a 45 degrees cut for perfect surface matching. The beamline optics is designed to take the advantage of the symmetry of mirrors such that a round focal spot is accomplished. The final size of the focus spot are simulated below 40 nm at 9-15 keV. The whole facility including the beamline and the stations will be operated under vacuum to preserve photon coherence as well as to prevent the system from unnecessary environmental interference. The station equips with multimodal x-ray probes, including XRF, XAS, XEOL, projection microscope, CDI, etc. A SEM in close cooperation with laser interferometers is equipped to precisely locate the position of the sample. The beamline and the station are scheduled to be in commissioning phase in 2016.

Advanced Kirkpatrick-Baez mirror optics using two monolithic imaging mirrors was developed to realize an achromatic, high-resolution, and a high-stability full-field X-ray microscope. The mirror consists of an elliptical section and a hyperbolic section on a quartz glass substrate, in which the geometry follows the Wolter (type I) optics rules. A preliminary test was performed at SPring-8 using X-rays monochromatized to 9.881 keV. A 100-nm feature on a Siemens star chart could be clearly observed.

The Full-field X-ray Imaging (FXI) beamline at the NSLS-II is designed for optimum performance of a transmission x-ray microscope (TXM). When complete, FXI will enable the TXM to obtain individual 2D projection images at 30 nm spatial resolution and up to 40 microns field of view (FOV) with exposure times of < 50 ms per image. A complete 3D nanotomography data set should take less than 1 minute. This will open opportunities for many real-time in-operando studies.

Ptychography combines elements of scanning probe microscopy with coherent diffractive imaging and provides a robust high-resolution imaging technique. The extension of X-ray ptychography to 3D provides nanoscale maps with quantitative contrast of the sample complex-valued refractive index. We present here progress in reconstruction and post-processing algorithms for ptychographic nanotomography, as well as outline advances in the implementation and development of dedicated instrumentation for fast and precise 3D scanning at the Swiss Light Source. Compared to the first demonstration in 2010, such developments have allowed a dramatic improvement in resolution and measurement speed, with direct impact in the application of the technique for biology and materials science. We showcase the technique by detailing the measurement and reconstruction of a fossilized dispersed spore.

Ptychography is an emerging high resolution coherent imaging technique which can improve the resolution of current scanning transmission X-ray microscopy systems by over ten-fold. Development of this capability is underway at Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, to establish sub-5 nm resolution ptychographic imaging with spatially resolved near-edge X-ray absorption fine structure spectroscopy. This is being achieved via an upgrade of the current soft X-ray scanning transmission X-ray microscope at beamline 13-1, involving the installation of an area detector and an interferometer system for high precision sample motor control. The undulator source on beamline 13-1 provides the spatially and temporally coherent X-ray beam required for ptychographic imaging in the energy range 500 – 1200 eV. This energy range allows access to the oxygen chemistry and the valence states of 3d transition metals found in energy storage materials, making soft x-ray ptychography a particularly powerful tool to study the chemical states and structure of battery materials at relevant length scales. The implementation of ptychographic imaging can therefore provide a wealth of additional information on battery operation and failure. Here we describe the development of this ptychography capability, along with its application to the study of energy storage materials.

The core-shell nanowires have the promise to become the future building blocks of light emitting diodes, solar cells and quantum computers. The high surface to volume ratio allows efficient elastic strain relaxation, making it possible to combine a wider range of materials into the heterostructures as compared to the traditional, planar geometry. As a result, the strain fields appear in both the core and the shell of the nanowires, which can affect the device properties. The hard x-ray nanoprobe is a tool that enables a nondestructive mapping of the strain and tilt distributions where other techniques cannot be applied. By measuring the positions of the Bragg peaks for each point on the sample we can evaluate the values of local tilt and strain. In this paper we demonstrate the detailed strain mapping of the strained InGaN/GaN core-shell nanowire. We observe an asymmetric strain distribution in the GaN core caused by an uneven shell relaxation. Additionally, we analyzed the local micro-tilt distribution, which shows the edge effects at the top and bottom of the nanowire. The measurements were compared to the finite element modelling and show a good agreement.

Hard x-ray focusing and imaging on the few nano metre scale has gained a lot of attraction in the last couple of years. Thanks to new developments in fabrication and inspection of high-N.A. optics, focusing of hard x-rays has caught up with the focusing performance for soft x-rays. Here we review the latest imaging experiments of the Göttinger Multilayer zone plate collaboration, summarising our route from 1D to 2D lenses for different hard x-ray energies, and recapitulate recent progress on a journey from focusing to imaging.

X-ray microscopy enables high spatial resolutions, high penetration depths and characterization of a broad range of materials. Calculations show that nanometer range resolution is achievable in the hard X-ray regime by using Fresnel zone plates (FZPs) if certain conditions are satisfied. However, this requires, among other things, aspect ratios of several thousands. The multilayer (ML) type FZPs, having virtually unlimited aspect ratios, are strong candidates to achieve single nanometer resolutions. Our research is focused on the fabrication of ML-FZPs which encompasses deposition of multilayers over a glass fiber via the atomic layer deposition (ALD), which is subsequently sliced in the optimum thickness for the X-ray energy by a focused ion beam (FIB). We recently achieved aberration free imaging by resolving 21 nm features with an efficiency of up to 12.5 %, the highest imaging resolution achieved by an ML-FZP. We also showed efficient focusing of 7.9 keV X-rays down to 30 nm focal spot size (FWHM). For resolutions below ~10 nm, efficiencies would decrease significantly due to wave coupling effects. To compensate this effect high efficiency, low stress materials have to be researched, as lower intrinsic stresses will allow fabrication of larger FZPs with higher number of zones, leading to high light intensity at the focus. As a first step we fabricated an ML-FZP with a diameter of 62 μm, an outermost zone width of 12 nm and 452 active zones. Further strategies for fabrication of high resolution high efficiency multilayer FZPs will also be discussed.

Zone plates are diffractive focusing optics capable of nanometer focusing but limited focusing efficiency at hard x-ray energy. A smaller focus spot is possible by reducing the outer zone width (OZW) while increasing the zone height will generally increase focusing efficiency. The combination of thick zones with small outer zone width, or high aspect ratio, for better performing zone plates is not feasible with state-of-the-art fabrication methods and requires other methods to achieve the aspect ratio desired. Near-field stacking involves two zone plates with the same dimensions and aligning them within the depth of focus in the beam direction and one third of the OZW in the transverse direction. Due to the depth of focus limitation, stacking more than 2 zone plates is extremely difficult, so a new method was proposed and developed to stack zone plates in the intermediate field. Multiple stacking apparatuses were assembled and tested. We will report on results from stacking 80-nm OZW zone plates from a near-field stacking experiment at 10 keV X-ray energy and intermediate field stacking 6 zone plates at 27 keV X-ray energy. We will also present findings on how to combine the stacking techniques.

Kinoform lenses are focusing optics with a 100 % theoretical focusing efficiency. Up to date, the actual continuous 3D surface relief profiles of X-ray kinoform lenses could only be approximately fabricated. Now, we have come up with an effective ion beam lithography fabrication strategy producing first-ever imaging-quality circularly symmetric kinoform lenses which demonstrated reasonably high focusing efficiencies. Here, we will discuss the potential of the fabrication method and the utility of kinoform lenses enabled by it. Special emphases will be placed on materials development including selection and design, efficiency considerations for various energies and possible applications.

Hard X-ray fluorescence (XRF) microscopy offers unparalleled sensitivity for quantitative analysis of most of the trace elements in biological samples, such as Fe, Cu, and Zn. These trace elements play critical roles in many biological processes. With the advanced nano-focusing optics, nowadays hard X-rays can be focused down to 30 nm or below and can probe trace elements within subcellular compartments. However, XRF imaging does not usually reveal much information on ultrastructure, because the main constituents of biomaterials, i.e. H, C, N, and O, have low fluorescence yield and little absorption contrast at multi-keV X-ray energies. An alternative technique for imaging ultrastructure is ptychography. One can record far-field diffraction patterns from a coherently illuminated sample, and then reconstruct the complex transmission function of the sample. In theory the spatial resolution of ptychography can reach the wavelength limit. In this manuscript, we will describe the implementation of ptychography at the Bionanoprobe (a recently developed hard XRF nanoprobe at the Advanced Photon Source) and demonstrate simultaneous ptychographic and XRF imaging of frozen-hydrated biological whole cells. This method allows locating trace elements within the subcellular structures of biological samples with high spatial resolution. Additionally, both ptychographic and XRF imaging are compatible with tomographic approach for 3D visualization.

In order to achieve high quality in situ spectroscopic X-ray microscopy of complex systems far from equilibrium, such as lithium ion batteries under standard electrochemical cycling, careful consideration of the total number of energy points is required. Enough energy points are need to accurately determine the per pixel chemical information; however, total radiation dose needs to be limited to avoid damaging the system which would produce misleading results. Here we consider the number of energy points need to accurately reproduce the state of charge maps of a LiFePO₂ electrode recorded during electrochemical cycling. We observe very good per pixel agreement using only 13 energy points. Additionally, we find the quality of the agreement is heavily dependent on the number of energy points used in the post edge fit during normalization of the spectra rather than the total number of energies used. Finally, we suggest a straightforward protocol for determining the minimum number of energy points needed prior to initiating any in situ spectroscopic X-ray microscopy experiment.

Engineering topics which span a range of length and time scales present a unique challenge to researchers. Hydraulic fracturing (fracking) of oil shales is one of these challenges and provides an opportunity to use multiple research tools to thoroughly investigate a topic. Currently, the extraction efficiency from the shale is low but can be improved by carefully studying the processes at the micro- and nano-scale. Fracking fluid induces chemical changes in the shale which can have significant effects on the microstructure morphology, permeability, and chemical composition. These phenomena occur at different length and time scales which require different instrumentation to properly study. Using synchrotron-based techniques such as fluorescence tomography provide high sensitivity elemental mapping and an in situ micro-tomography system records morphological changes with time. In addition, the transmission X-ray microscope (TXM) at the Stanford Synchrotron Radiation Lightsource (SSRL) beamline 6-2 is utilized to collect a nano-scale three-dimensional representation of the sample morphology with elemental and chemical sensitivity. We present the study of a simplified model system, in which pyrite and quartz particles are mixed and exposed to oxidizing solution, to establish the basic understanding of the more complex geology-relevant oxidation reaction. The spatial distribution of the production of the oxidation reaction, ferrihydrite, is retrieved via full-field XANES tomography showing the reaction pathway. Further correlation between the high resolution TXM data and the high sensitivity micro-probe data provides insight into potential morphology changes which can decrease permeability and limit hydrocarbon recovery.

X-ray microscopy (XRM) has emerged as a powerful technique that reveals 3D images and quantitative information of interior structures. XRM executed both in the laboratory and at the synchrotron have demonstrated critical analysis and materials characterization on meso-, micro-, and nanoscales, with spatial resolution down to 50 nm in laboratory systems. The non-destructive nature of X-rays has made the technique widely appealing, with potential for “4D” characterization, delivering 3D micro- and nanostructural information on the same sample as a function of sequential processing or experimental conditions. Understanding volumetric and nanostructural changes, such as solid deformation, pore evolution, and crack propagation are fundamental to understanding how materials form, deform, and perform. We will present recent instrumentation developments in laboratory based XRM including a novel in situ nanomechanical testing stage. These developments bridge the gap between existing in situ stages for micro scale XRM, and SEM/TEM techniques that offer nanometer resolution but are limited to analysis of surfaces or extremely thin samples whose behavior is strongly influenced by surface effects. Several applications will be presented including 3D-characterization and in situ mechanical testing of polymers, metal alloys, composites and biomaterials. They span multiple length scales from the micro- to the nanoscale and different mechanical testing modes such as compression, indentation and tension.

X-ray Bragg ptychography (XBP) is an experimental technique for high-resolution strain mapping in a single nano- and mesoscopic crystalline structures. In this work we discuss the conditions that allow direct interpretation of the ptychographic reconstructions in terms of the strain distribution obtained from the two dimensional (2D) XBP. Simulations of the 2D XBP experiments under realistic experimental conditions are performed with a model of InGaN/GaN core-shell nanowire with low (1%) and high (30%) Indium concentrations in the shell.

X-ray fluorescence offers unparalleled sensitivity for imaging the nanoscale distribution of trace elements in micrometer thick samples, while x-ray ptychography offers an approach to image weakly fluorescing lighter elements at a resolution beyond that of the x-ray lens used. These methods can be used in combination, and in continuous scan mode for rapid data acquisition when using multiple probe mode reconstruction methods. We discuss here the opportunities and limitations of making use of additional information provided by ptychography to improve x-ray fluorescence images in two ways: by using position-error-correction algorithms to correct for scan distortions in fluorescence scans, and by considering the signal-to-noise limits on previously-demonstrated ptychographic probe deconvolution methods. This highlights the advantages of using a combined approach.

X-ray fluorescence tomography involves the acquisition of a series of 2D x-ray fluorescence datasets between which a specimen is rotated. At the Advanced Photon Source at Argonne National Laboratory, the workflow at beamlines 2-ID-E and 21-ID-D (the Bionanoprobe, a cryogenic microscope system) has included the use of the program MAPS for obtaining elemental concentrations from 2D images, and the program TomoPy which was developed to include several tomographic reconstruction methods for x-ray transmission data. In the past, fluorescence projection images from an individual chemical element were hand-assembled into a 3D dataset for reconstruction using interactive tools such as ImageJ. We describe here the program MAPSToTomoPy, which provides a graphical user interface (GUI) to control a workflow between MAPS and TomoPy, with tools for visualizing the sinograms of projection image sequences from particular elements and to use these to help correct misalignments of the rotation axis. The program also provides an integrated output of the 3D distribution of the detected elements for subsequent 3D visualization packages.

Combining sub-micron spatial resolution full-field-imaging with the penetration property of high-energy x-rays (> 50 keV) offers numerous applications, such as the ability to observe cracks and voids associated with the onset of failure in engineering materials, complementing x-ray diffraction microscopy probes. Progress in the development of adding such an imaging capability at the Advanced Photon Source high-energy x-ray undulator beamline 1-ID is reported. An initially tested, long baseline configuration had 18-21× x-ray image magnification with compound refractive lenses (as objective) placed 1.8 m after the specimen, and a two-dimensional detector located at a 32–37 m additional distance, in a different experimental station. Later, a more compact set-up of 3.5× magnification with a ≈6 m sample-to-detector separation, fitting within a single end-station, was tested. Both set-ups demonstrated 500 nm level spatial resolutions at energies within the 45–50 keV range. Phase contrast artifacts are present, and are discussed in view of the goal of achieving tomography capability, at even higher resolution, in such an instrument with high x-ray energies.