Nanofocusing with aberration-corrected rotationally   parabolic refractive X-ray lenses
Wavefront errors of rotationally parabolic refractive X-ray lenses made of beryllium (Be CRLs) have been recovered for various lens sets and X-ray beam configurations. Due to manufacturing via an embossing process, aberrations of individual lenses within the investigated ensemble are very similar. By deriving a mean single-lens deformation for the ensemble, aberrations of any arbitrary lens stack can be predicted from the ensemble with \bar{\sigma} = 0.034 λ . Using these findings the expected focusing performance of current Be CRLs are modeled for relevant X-ray energies and bandwidths and it is shown that a correc...
Source: Journal of Synchrotron Radiation - December 7, 2017 Category: Physics Authors: Seiboth, F. Wittwer, F. Scholz, M. Kahnt, M. Seyrich, M. Schropp, A. Wagner, U. Rau, C. Garrevoet, J. Falkenberg, G. Schroer, C.G. Tags: refractive X-ray optics aberration correction ptychography phase plate research papers Source Type: research

Efficient high-order suppression system for a metrology beamline
High-quality metrology with synchrotron radiation requires in particular a very high spectral purity of the incident beam. This is usually achieved by a set of transmission filters with suitable absorption edges to suppress high-order radiation of the monochromator. The at-wavelength metrology station at a BESSY-II bending-magnet collimated plane-grating monochromator (c-PGM) beamline has recently commissioned a high-order suppression system (HiOS) based on four reflections from mirrors which can be inserted into the beam path. Two pairs of mirrors are aligned parallel so as not to disturb the original beam path and are ro...
Source: Journal of Synchrotron Radiation - December 7, 2017 Category: Physics Authors: Sokolov, A. Sertsu, M.G. Gaupp, A. L ü ttecke, M. Sch ä fers, F. Tags: reflectometer higher orders PGM beamline at-wavelength metrology XUV optical elements diffraction gratings research papers Source Type: research

Non-invasive online wavelength measurements at   FLASH2 and present benchmark
At FLASH2, the free-electron laser radiation wavelength is routinely measured by an online spectrometer based on photoionization of gas targets. Photoelectrons are detected with time-of-flight spectrometers and the wavelength is determined by means of well known binding energies of the target species. The wavelength measurement is non-invasive and transparent with respect to running user experiments due to the low gas pressure applied. Sophisticated controls for setting the OPIS operation parameters have been created and integrated into the distributed object-oriented control system at FLASH2. Raw and processed data can be...
Source: Journal of Synchrotron Radiation - December 7, 2017 Category: Physics Authors: Braune, M. Buck, J. Kuhlmann, M. Grunewald, S. D ü sterer, S. Viefhaus, J. Tiedtke, K. Tags: free-electron laser soft X-ray wavelength photoionization rare gases research papers Source Type: research

Performance of a hard X-ray split-and-delay optical system with a wavefront division
The performance of a hard X-ray split-and-delay optical (SDO) system with a wavefront division scheme was investigated at the hard X-ray free-electron laser facility SACLA. For the wavefront division, beam splitters made of edge-polished perfect Si(220) crystals were employed. We characterized the beam properties of the SDO system, and investigated its capabilities for beam manipulation and diagnostics. First, it was confirmed that shot-to-shot non-invasive diagnostics of pulse energies for both branches in the SDO system was feasible. Second, nearly ideal and identical focal profiles for both branches were obtained with a...
Source: Journal of Synchrotron Radiation - December 6, 2017 Category: Physics Authors: Hirano, T. Osaka, T. Morioka, Y. Sano, Y. Inubushi, Y. Togashi, T. Inoue, I. Matsuyama, S. Tono, K. Robert, A. Hastings, J.B. Yamauchi, K. Yabashi, M. Tags: hard X-ray free-electron laser split-and-delay optics multi-crystal optics X-ray photon correlation spectroscopy research papers Source Type: research

Diffraction gratings metrology and ray-tracing results for an XUV Raman spectrometer at FLASH
The extreme-ultraviolet double-stage imaging Raman spectrometer is a permanent experimental endstation at the plane-grating monochromator beamline branch PG1 at FLASH at DESY in Hamburg, Germany. This unique instrument covers the photon energy range from 20 to 200   eV with high energy resolution of about 2 to 20   meV (design values) featuring an efficient elastic line suppression as well as effective stray light rejection. Such a design enables studies of low-energy excitations like, for example, phonons in solids close to the vicinity of the elastic line. The Raman spectrometer effectively operates with four reflect...
Source: Journal of Synchrotron Radiation - December 6, 2017 Category: Physics Authors: Dziarzhytski, S. Siewert, F. Sokolov, A. Gwalt, G. Seliger, T. R ü bhausen, M. Weigelt, H. Brenner, G. Tags: X-ray optics XUV Raman spectrometer metrology for synchrotron optics NOM reflectometry ray tracing research papers Source Type: research

X-ray beam-shaping via deformable mirrors: surface profile and point spread function computation for Gaussian beams using physical optics
X-ray mirrors with high focusing performances are commonly used in different sectors of science, such as X-ray astronomy, medical imaging and synchrotron/free-electron laser beamlines. While deformations of the mirror profile may cause degradation of the focus sharpness, a deliberate deformation of the mirror can be made to endow the focus with a desired size and distribution, via piezo actuators. The resulting profile can be characterized with suitable metrology tools and correlated with the expected optical quality via a wavefront propagation code or, sometimes, predicted using geometric optics. In the latter case and fo...
Source: Journal of Synchrotron Radiation - December 6, 2017 Category: Physics Authors: Spiga, D. Tags: X-ray mirrors active optics beam-shaping physical optics research papers Source Type: research

FLASH free-electron laser single-shot temporal diagnostic: terahertz-field-driven streaking
The commissioning of a terahertz-field-driven streak camera installed at the free-electron laser (FEL) FLASH at DESY in Hamburg, being able to deliver photon pulse duration as well as arrival time information with ∼ 10   fs resolution for each single XUV FEL pulse, is reported. Pulse durations between 300   fs and (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - December 6, 2017 Category: Physics Authors: Ivanov, R. Liu, J. Brenner, G. Brachmanski, M. D ü sterer, S. Tags: free-electron laser FLASH SASE photon pulse duration photon pulse arrival time terahertz streaking research papers Source Type: research

A compact and versatile tender X-ray single-shot spectrometer for online XFEL diagnostics
One of the remaining challenges for accurate photon diagnostics at X-ray free-electron lasers (FELs) is the shot-to-shot, non-destructive, high-resolution characterization of the FEL pulse spectrum at photon energies between 2   keV and 4   keV, the so-called tender X-ray range. Here, a spectrometer setup is reported, based on the von Hamos geometry and using elastic scattering as a fingerprint of the FEL-generated spectrum. It is capable of pulse-to-pulse measurement of the spectrum with an energy resolution ( Δ E/E) of 10 − 4, within a bandwidth of 2%. The Tender X-ray Single-Shot Spectrometer (TXS) will ...
Source: Journal of Synchrotron Radiation - December 6, 2017 Category: Physics Authors: Rehanek, J. Milne, C.J. Szlachetko, J. Czapla-Masztafiak, J. Schneider, J. Huthwelker, T. Borca, C.N. Wetter, R. Patthey, L. Jurani ć , P. Tags: free-electron laser tender X-ray spectroscopy single-shot measurement research papers Source Type: research

Current events
(Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - October 31, 2017 Category: Physics Authors: , Tags: current events Source Type: research

Scanning X-ray diffraction on cardiac tissue: automatized data analysis and processing
A scanning X-ray diffraction study of cardiac tissue has ben performed, covering the entire cross section of a mouse heart slice. To this end, moderate focusing by compound refractive lenses to micrometer spot size, continuous scanning, data acquisition by a fast single-photon-counting pixel detector, and fully automated analysis scripts have been combined. It was show that a surprising amount of structural data can be harvested from such a scan, evaluating the local scattering intensity, interfilament spacing of the muscle tissue, the filament orientation, and the degree of anisotropy. The workflow of data analysis is des...
Source: Journal of Synchrotron Radiation - October 23, 2017 Category: Physics Authors: Nicolas, J.-D. Bernhardt, M. Markus, A. Alves, F. Burghammer, M. Salditt, T. Tags: scanning SAXS cardiac muscle small-angle X-ray scattering micro-diffraction research papers Source Type: research

Characterization of a bent Laue double-crystal beam-expanding monochromator
A bent Laue double-crystal monochromator system has been designed for vertically expanding the X-ray beam at the Canadian Light Source's BioMedical Imaging and Therapy beamlines. Expansion by a factor of 12 has been achieved without deteriorating the transverse coherence of the beam, allowing phase-based imaging techniques to be performed with high flux and a large field of view. However, preliminary studies revealed a lack of uniformity in the beam, presumed to be caused by imperfect bending of the silicon crystal wafers used in the system. Results from finite-element analysis of the system predicted that the second cryst...
Source: Journal of Synchrotron Radiation - October 19, 2017 Category: Physics Authors: Martinson, M. Samadi, N. Shi, X. Liu, Z. Assoufid, L. Chapman, D. Tags: beam expander double bent Laue monochromator Lang topography Berg – Barrett topography finite-element analysis research papers Source Type: research

Early commissioning results for spectroscopic X-ray Nano-Imaging Beamline BL 7C sXNI at PLS-II
For spectral imaging of chemical distributions using X-ray absorption near-edge structure (XANES) spectra, a modified double-crystal monochromator, a focusing plane mirrors system and a newly developed fluorescence-type X-ray beam-position monitoring and feedback system have been implemented. This major hardware upgrade provides a sufficiently stable X-ray source during energy scanning of more than hundreds of eV for acquisition of reliable XANES spectra in two-dimensional and three-dimensional images. In recent pilot studies discussed in this paper, heavy-metal uptake by plant roots in vivo and iron's phase distribution i...
Source: Journal of Synchrotron Radiation - October 18, 2017 Category: Physics Authors: Lee, S. Kwon, I. Kim, J.-Y. Yang, S.-S. Kang, S. Lim, J. Tags: X-ray nano-imaging tomography XANES imaging battery beamlines Source Type: research

The slip-and-slide algorithm: a refinement protocol for detector geometry
Geometry correction is traditionally plagued by mis-fitting of correlated parameters, leading to local minima which prevent further improvements. Segmented detectors pose an enhanced risk of mis-fitting: even a minor confusion of detector distance and panel separation can prevent improvement in data quality. The slip-and-slide algorithm breaks down effects of the correlated parameters and their associated target functions in a fundamental shift in the approach to the problem. Parameters are never refined against the components of the data to which they are insensitive, providing a dramatic boost in the exploitation of info...
Source: Journal of Synchrotron Radiation - October 18, 2017 Category: Physics Authors: Ginn, H.M. Stuart, D.I. Tags: serial crystallography free-electron laser SFX stills XFEL detector geometry research papers Source Type: research

Phase contrast imaging of preclinical portal vein   embolization with CO2 microbubbles
In this study, the feasibility of using phase contrast imaging (PCI) to show PVE using homemade CO2 microbubbles in living rats has been investigated. CO2 gas was first formed from the reaction between citric acid and sodium bicarbonate. The CO2 gas was then encapsulated by egg white to fabricate CO2 microbubbles. ACI and PCI of CO2 microbubbles were performed and compared in vitro. An additional increase in contrast was detected in PCI. PCI showed that CO2 microbubbles gradually dissolved over time, and the remaining CO2 microbubbles became larger. By PCI, the CO2 microbubbles were found to have certain stability, suggest...
Source: Journal of Synchrotron Radiation - October 17, 2017 Category: Physics Authors: Tang, R. Yan, F. Yang, G.-Y. Chen, K.-M. Tags: phase contrast imaging portal vein embolization CO2 microbubbles research papers Source Type: research

GigaFRoST: the gigabit fast readout system for tomography
Owing to recent developments in CMOS technology, it is now possible to exploit tomographic microscopy at third-generation synchrotron facilities with unprecedented speeds. Despite this rapid technical progress, one crucial limitation for the investigation of realistic dynamic systems has remained: a generally short total acquisition time at high frame rates due to the limited internal memory of available detectors. To address and solve this shortcoming, a new detection and readout system, coined GigaFRoST, has been developed based on a commercial CMOS sensor, acquiring and streaming data continuously at 7.7   GB   s &m...
Source: Journal of Synchrotron Radiation - October 17, 2017 Category: Physics Authors: Mokso, R. Schlep ü tz, C.M. Theidel, G. Billich, H. Schmid, E. Celcer, T. Mikuljan, G. Sala, L. Marone, F. Schlumpf, N. Stampanoni, M. Tags: X-ray tomographic microscopy 4D   imaging high-speed camera fast readout system evolution of dynamic systems research papers Source Type: research

Surface plasmon band tailoring of plasmonic nanostructure under the effect of water radiolysis by synchrotron radiation
Plasmonic metal nanostructures have a significant impact on a diverse domain of fields, including photocatalysis, antibacterial, drug vector, biosensors, photovoltaic cell, optical and electronic devices. Metal nanoparticles (MNps) are the simplest nanostructure promising ultrahigh stability, ease of manufacturing and tunable optical response. Silver nanoparticles (AgNp) dominate in the class of MNps because of their relatively high abundance, chemical activity and unique physical properties. Although MNps offer the desired physical properties, most of the synthesis and fabrication methods lag at the electronic grade due t...
Source: Journal of Synchrotron Radiation - October 17, 2017 Category: Physics Authors: Bharti, A. Agrawal, A.K. Singh, B. Gautam, S. Goyal, N. Tags: plasmonic nanostructure silver nanoparticles X-rays Mie theory water radiolysis research papers Source Type: research

Post-sample aperture for low background diffraction experiments at X-ray free-electron lasers
The success of diffraction experiments from weakly scattering samples strongly depends on achieving an optimal signal-to-noise ratio. This is particularly important in single-particle imaging experiments where diffraction signals are typically very weak and the experiments are often accompanied by significant background scattering. A simple way to tremendously reduce background scattering by placing an aperture downstream of the sample has been developed and its application in a single-particle X-ray imaging experiment at FLASH is demonstrated. Using the concept of a post-sample aperture it was possible to reduce the backg...
Source: Journal of Synchrotron Radiation - October 16, 2017 Category: Physics Authors: Wiedorn, M.O. Awel, S. Morgan, A.J. Barthelmess, M. Bean, R. Beyerlein, K.R. Chavas, L.M.G. Eckerskorn, N. Fleckenstein, H. Heymann, M. Horke, D.A. Kno š ka, J. Mariani, V. Oberth ü r, D. Roth, N. Yefanov, O. Barty, A. Bajt, S. K ü pper, J. Rode, A.V. Tags: X-ray diffraction single-particle imaging coherent diffractive imaging aperture background scattering signal-to-noise ratio laboratory notes Source Type: research

Enhancement of radiosensitivity of oral carcinoma cells by iodinated chlorin p6 copper complex in combination with synchrotron X-ray radiation
In this study the anticancer cytotoxic efficacy of a new chlorophyll derivative, iodinated chlorin p6 copper complex (ICp6-Cu), combined with synchrotron X-ray radiation (8 – 10   keV) in two human oral cancer cell lines is explored. Pre-treatment of cells with 20   µ M and 30   µ M ICp6-Cu for 3   h was found to enhance the X-ray-induced cytotoxicity with sensitization enhancement ratios of 1.8 and 2.8, respectively. ICp6-Cu localized in cytoplasm, mainly in lysosomes and endoplasmic reticulum, and did not cause any cytotoxicity alone. The radiosensitization effect of ICp6-Cu accompanied a signif...
Source: Journal of Synchrotron Radiation - October 16, 2017 Category: Physics Authors: Sarbadhikary, P. Dube, A. Tags: chlorophyll derivative DNA damage radiosensitization reactive oxygen species synchrotron photon activation therapy research papers Source Type: research

Refraction and ultra-small-angle scattering of X-rays in a single-crystal diamond compound refractive lens
In this work a double-crystal setup is employed to study compound refractive lenses made of single-crystal diamond. The point spread function of the lens is calculated taking into account the lens transmission, the wavefront aberrations, and the ultra-small-angle broadening of the X-ray beam. It is shown that, similarly to the wavefront aberrations, the ultra-small-angle scattering effects can significantly reduce the intensity gain and increase the focal spot size. The suggested approach can be particularly useful for the characterization of refractive X-ray lenses composed of many tens of unit lenses. (Source: Journal of...
Source: Journal of Synchrotron Radiation - October 13, 2017 Category: Physics Authors: Gasilov, S. Mittone, A. Santos Rolo, T. dos Polyakov, S. Zholudev, S. Terentyev, S. Blank, V. Bravin, A. Baumbach, T. Tags: compound refractive lens single-crystal diamond aberrations ultra-small angle X-ray scattering rocking-curve imaging research papers Source Type: research

The emerging role of 4D synchrotron X-ray micro-tomography for climate and fossil energy studies: five experiments showing the present capabilities at   beamline 8.3.2 at the Advanced Light Source
Continuous improvements at X-ray imaging beamlines at synchrotron light sources have made dynamic synchrotron X-ray micro-computed tomography (SXR- µ CT) experiments more routinely available to users, with a rapid increase in demand given its tremendous potential in very diverse areas. In this work a survey of five different four-dimensional SXR- µ CT experiments is presented, examining five different parameters linked to the evolution of the investigated system, and tackling problems in different areas in earth sciences. SXR- µ CT is used to monitor the microstructural evolution of the investigated sampl...
Source: Journal of Synchrotron Radiation - October 13, 2017 Category: Physics Authors: Voltolini, M. Haboub, A. Dou, S. Kwon, T.-H. MacDowell, A.A. Parkinson, D.Y. Ajo-Franklin, J. Tags: X-ray microCT in situ imaging earth and energy sciences research papers Source Type: research

Characterization of a sCMOS-based high-resolution imaging system
The detection system is a key part of any imaging station. Here the performance of the novel sCMOS-based detection system installed at the ID17 biomedical beamline of the European Synchrotron Radiation Facility and dedicated to high-resolution computed-tomography imaging is analysed. The system consists of an X-ray – visible-light converter, a visible-light optics and a PCO.Edge5.5 sCMOS detector. Measurements of the optical characteristics, the linearity of the system, the detection lag, the modulation transfer function, the normalized power spectrum, the detective quantum efficiency and the photon transfer curve ar...
Source: Journal of Synchrotron Radiation - October 13, 2017 Category: Physics Authors: Mittone, A. Manakov, I. Broche, L. Jarnias, C. Coan, P. Bravin, A. Tags: image detector X-ray imaging image quality research papers Source Type: research

syris: a flexible and efficient framework for X-ray imaging experiments simulation
An open-source framework for conducting a broad range of virtual X-ray imaging experiments, syris, is presented. The simulated wavefield created by a source propagates through an arbitrary number of objects until it reaches a detector. The objects in the light path and the source are time-dependent, which enables simulations of dynamic experiments, e.g. four-dimensional time-resolved tomography and laminography. The high-level interface of syris is written in Python and its modularity makes the framework very flexible. The computationally demanding parts behind this interface are implemented in OpenCL, which enables fast c...
Source: Journal of Synchrotron Radiation - October 9, 2017 Category: Physics Authors: Farag ó , T. Mikul í k, P. Ershov, A. Vogelgesang, M. H ä nschke, D. Baumbach, T. Tags: simulation high-speed imaging parallelization free-space propagation coherence X-ray imaging synchrotron radiation computer programs Source Type: research

Characterization of X-ray gas attenuator plasmas by   optical emission and tunable laser absorption spectroscopies
The objective of this work is to demonstrate experimentally the generation of plasma by the X-ray beam and to investigate its spatial distribution by measuring some of its parameters, simultaneously with the X-ray power absorption. The gases used in this study were argon and krypton between 13 and 530   mbar. The distribution of the 2p excited states of both gases was measured using optical emission spectroscopy, and the density of argon metastable atoms in the 1s5 state was deduced using tunable laser absorption spectroscopy. The amount of power absorbed was measured using calorimetry and X-ray transmission. The results...
Source: Journal of Synchrotron Radiation - October 6, 2017 Category: Physics Authors: Mart í n Ortega, Á . Lacoste, A. B é chu, S. B è s, A. Sadeghi, N. Tags: gas attenuator power absorption optical emission spectroscopy tunable laser absorption spectroscopy plasma research papers Source Type: research

Aberration-free aspherical lens shape for shortening the focal distance of an already convergent beam
The shapes of single lens surfaces capable of focusing divergent and collimated beams without aberration have already been calculated. However, nanofocusing compound refractive lenses (CRLs) require many consecutive lens surfaces. Here a theoretical example of an X-ray nanofocusing CRL with 48 consecutive surfaces is studied. The surfaces on the downstream end of this CRL accept X-rays that are already converging toward a focus, and refract them toward a new focal point that is closer to the surface. This case, so far missing from the literature, is treated here. The ideal surface for aberration-free focusing of a converge...
Source: Journal of Synchrotron Radiation - October 6, 2017 Category: Physics Authors: Sutter, J.P. Alianelli, L. Tags: X-ray lens oval nanofocusing aberration research papers Source Type: research

Simulations of Co-GISAXS during kinetic roughening of growth surfaces
The recent development of surface growth studies using X-ray photon correlation spectroscopy in a grazing-incidence small-angle X-ray scattering (Co-GISAXS) geometry enables the investigation of dynamical processes during kinetic roughening in greater detail than was previously possible. In order to investigate the Co-GISAXS behavior expected from existing growth models, calculations and (2+1)-dimension simulations of linear Kuramoto – Sivashinsky and non-linear Kardar – Parisi – Zhang surface growth equations are presented which analyze the temporal correlation functions of the height – height stru...
Source: Journal of Synchrotron Radiation - October 5, 2017 Category: Physics Authors: Mokhtarzadeh, M. Ludwig, K.F.Jr Tags: XPCS Co-GISAXS KPZ simulations surface growth correlation functions research papers Source Type: research

A novel method for resonant inelastic soft X-ray scattering via photoelectron spectroscopy detection
A method for measuring resonant inelastic X-ray scattering based on the conversion of X-ray photons into photoelectrons is presented. The setup is compact, relies on commercially available detectors, and offers significant flexibility. This method is demonstrated at the Linac Coherent Light Source with ∼ 0.5   eV resolution at the cobalt L3-edge, with signal rates comparable with traditional grating spectrometers. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - October 5, 2017 Category: Physics Authors: Dakovski, G.L. Lin, M.-F. Damiani, D.S. Schlotter, W.F. Turner, J.J. Nordlund, D. Ogasawara, H. Tags: RIXS soft X-ray spectroscopy FEL research papers Source Type: research

The effect of self-consistent potentials on EXAFS analysis
A theory program intended for use with extended X-ray-absorption fine structure (EXAFS) spectroscopy and based on the popular FEFF8 is presented. It provides an application programming interface designed to make it easy to integrate high-quality theory into EXAFS analysis software. This new code is then used to examine the impact of self-consistent scattering potentials on EXAFS data analysis by methodical testing of theoretical fitting standards against a curated suite of measured EXAFS data. For each data set, the results of a fit are compared using a well characterized structural model and theoretical fitting standards ...
Source: Journal of Synchrotron Radiation - October 4, 2017 Category: Physics Authors: Ravel, B. Newville, M. Kas, J.J. Rehr, J.J. Tags: EXAFS real-space multiple scattering data analysis research papers Source Type: research

Design and performance of an X-ray scanning microscope at the Hard X-ray Nanoprobe beamline of NSLS-II
A hard X-ray scanning microscope installed at the Hard X-ray Nanoprobe beamline of the National Synchrotron Light Source II has been designed, constructed and commissioned. The microscope relies on a compact, high stiffness, low heat dissipation approach and utilizes two types of nanofocusing optics. It is capable of imaging with ∼ 15   nm × 15   nm spatial resolution using multilayer Laue lenses and 25   nm × 26   nm resolution using zone plates. Fluorescence, diffraction, absorption, differential phase contrast, ptychography and tomography are available as experimental techniques. The microscope i...
Source: Journal of Synchrotron Radiation - October 4, 2017 Category: Physics Authors: Nazaretski, E. Yan, H. Lauer, K. Bouet, N. Huang, X. Xu, W. Zhou, J. Shu, D. Hwu, Y. Chu, Y.S. Tags: X-ray microscopy multilayer Laue lenses nanoprobes research papers Source Type: research

The 3D characteristics of post-traumatic syringomyelia in a rat model: a propagation-based synchrotron radiation microtomography study
This study demonstrated that high-resolution PB-SR µ CT could be used for the 3D visualization of trauma-induced spinal cord cavities and provides valuable quantitative data for cavity characterization. PB-SR µ CT could be used as a reliable imaging technique and offers a novel platform for tracking cavity formation and morphological changes in an experimental animal model of PTS. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - October 4, 2017 Category: Physics Authors: Liao, S. Ni, S. Cao, Y. Yin, X. Wu, T. Lu, H. Hu, J. Wu, H. Lang, Y. Tags: post-traumatic syringomyelia three-dimensional propagation-based synchrotron radiation microtomography spinal cord injury phase-contrast tomography research papers Source Type: research

In situ beamline analysis and correction of active   optics. Erratum
A correction to one of the equations in the paper by Sutter et al. (2012). [J.   Synchrotron Rad. 19, 960 – 968] is made. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - August 31, 2017 Category: Physics Authors: Sutter, J. Alcock, S. Sawhney, K. Tags: in situ correction X-ray mirror. addenda and errata Source Type: research

Seventy years of publications
(Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - August 31, 2017 Category: Physics Authors: Hasnain, S.S. Tags: editorial IUCr Journals Source Type: research

Insight into 3D micro-CT data: exploring segmentation algorithms through performance metrics
Three-dimensional (3D) micro-tomography ( µ -CT) has proven to be an important imaging modality in industry and scientific domains. Understanding the properties of material structure and behavior has produced many scientific advances. An important component of the 3D µ -CT pipeline is image partitioning (or image segmentation), a step that is used to separate various phases or components in an image. Image partitioning schemes require specific rules for different scientific fields, but a common strategy consists of devising metrics to quantify performance and accuracy. The present article proposes a set of prot...
Source: Journal of Synchrotron Radiation - August 23, 2017 Category: Physics Authors: Perciano, T. Ushizima, D. Krishnan, H. Parkinson, D. Larson, N. Pelt, D.M.. Bethel, W. Zok, F. Sethian, J. Tags: unsupervised segmentation micro-tomography ceramic matrix composites image analysis research papers Source Type: research

Nanosecond pump – probe device for time-resolved serial femtosecond crystallography developed at SACLA
X-ray free-electron lasers (XFELs) have opened new opportunities for time-resolved X-ray crystallography. Here a nanosecond optical-pump XFEL-probe device developed for time-resolved serial femtosecond crystallography (TR-SFX) studies of photo-induced reactions in proteins at the SPring-8 Angstrom Compact free-electron LAser (SACLA) is reported. The optical-fiber-based system is a good choice for a quick setup in a limited beam time and allows pump illumination from two directions to achieve high excitation efficiency of protein microcrystals. Two types of injectors are used: one for extruding highly viscous samples such a...
Source: Journal of Synchrotron Radiation - August 22, 2017 Category: Physics Authors: Kubo, M. Nango, E. Tono, K. Kimura, T. Owada, S. Song, C. Mafun é , F. Miyajima, K. Takeda, Y. Kohno, J. Miyauchi, N. Nakane, T. Tanaka, T. Nomura, T. Davidsson, J. Tanaka, R. Murata, M. Kameshima, T. Hatsui, T. Joti, Y. Neutze, R. Yabashi, M. Iwata, S. Tags: XFEL serial femtosecond crystallography time-resolved X-ray crystallography pump and probe short communications Source Type: research

Artifact reduction in the CSPAD detectors used for LCLS experiments
The existence of noise and column-wise artifacts in the CSPAD-140K detector and in a module of the CSPAD-2.3M large camera, respectively, is reported for the L730 and L867 experiments performed at the CXI Instrument at the Linac Coherent Light Source (LCLS), in low-flux and low signal-to-noise ratio regime. Possible remedies are discussed and an additional step in the preprocessing of data is introduced, which consists of performing a median subtraction along the columns of the detector modules. Thus, we reduce the overall variation in the photon count distribution, lowering the mean false-positive photon detection rate by...
Source: Journal of Synchrotron Radiation - August 22, 2017 Category: Physics Authors: Pietrini, A. Nettelblad, C. Tags: CSPAD detector artifact LCLS CXI short communications Source Type: research

Investigation of nanoparticulate silicon as printed layers using scanning electron microscopy, transmission electron microscopy, X-ray absorption spectroscopy and X-ray photoelectron spectroscopy
The presence of native oxide on the surface of silicon nanoparticles is known to inhibit charge transport on the surfaces. Scanning electron microscopy (SEM) studies reveal that the particles in the printed silicon network have a wide range of sizes and shapes. High-resolution transmission electron microscopy reveals that the particle surfaces have mainly the (111)- and (100)-oriented planes which stabilizes against further oxidation of the particles. X-ray absorption spectroscopy (XANES) and X-ray photoelectron spectroscopy (XPS) measurements at the O 1s-edge have been utilized to study the oxidation and local atomic stru...
Source: Journal of Synchrotron Radiation - August 21, 2017 Category: Physics Authors: Unuigbe, D.M. Harting, M. Jonah, E.O. Britton, D.T. Nordlund, D. Tags: native oxide charge transport sub-oxide states XANES XPS SEM network structures printed layers research papers Source Type: research

Local structure around In atoms in coherently grown m-plane InGaN film
The local structure around In atoms in an m-plane In0.06Ga0.94N film coherently grown on a freestanding m-plane GaN substrate was investigated by polarization-dependent X-ray absorption fine-structure. A step-by-step fitting procedure was proposed for the m-plane wurtzite structure. The interatomic distance for the first nearest neighbour In — N atomic pairs was almost isotropic. For the second nearest In — Ga pairs, the interatomic distances along the m- and a-axes were longer and shorter, respectively, than that in strain-free virtual crystals as expected for the m-plane compressive strain. In contrast, the I...
Source: Journal of Synchrotron Radiation - August 21, 2017 Category: Physics Authors: Miyanaga, T. Azuhata, T. Nitta, K. Chichibu, S.F. Tags: m-plane InGaN XAFS local structure step-by-step fitting procedure research papers Source Type: research

Mutual optical intensity propagation through non-ideal mirrors
The mutual optical intensity (MOI) model is extended to include the propagation of partially coherent radiation through non-ideal mirrors. The propagation of the MOI from the incident to the exit plane of the mirror is realised by local ray tracing. The effects of figure errors can be expressed as phase shifts obtained by either the phase projection approach or the direct path length method. Using the MOI model, the effects of figure errors are studied for diffraction-limited cases using elliptical cylinder mirrors. Figure errors with low spatial frequencies can vary the intensity distribution, redistribute the local coher...
Source: Journal of Synchrotron Radiation - August 18, 2017 Category: Physics Authors: Meng, X. Shi, X. Wang, Y. Reininger, R. Assoufid, L. Tai, R. Tags: partially coherent radiation mutual optical intensity non-ideal mirrors beamline design mirror figure errors research papers Source Type: research

Characterization of enamel caries lesions in rat molars using synchrotron X-ray microtomography
Dental caries is a ubiquitous infectious disease with a nearly 100% lifetime prevalence. Rodent caries models are widely used to investigate the etiology, progression and potential prevention or treatment of the disease. To explore the suitability of these models for deeper investigations of intact surface zones during enamel caries, the structures of early-stage carious lesions in rats were characterized and compared with previous reports on white spot enamel lesions in humans. Synchrotron X-ray microcomputed tomography non-destructively mapped demineralization in carious rat molar specimens across a range of caries sever...
Source: Journal of Synchrotron Radiation - August 18, 2017 Category: Physics Authors: Free, R.D. DeRocher, K. Stock, S.R. Keane, D. Scott-Anne, K. Bowen, W.H. Joester, D. Tags: X-ray microtomography white spot enamel lesions surface zones caries research papers Source Type: research

Non-uniform nanosecond gate-delay of hybrid pixel   detectors
A simple experiment to characterize the gating properties of X-ray area detectors using pulsed X-ray sources is presented. For a number of time-resolved experiments the gating uniformity of area detectors is important. Relative gating delays between individual modules and readout chips of PILATUS2   series area X-ray detectors have been observed. For three modules of a PILATUS   300K-W unit the maximum gating offset between the modules is found to be as large as 30   ns. On average, the first photosensor module is found to be triggered 15   ns and 30   ns later than the second and the third modules, respective...
Source: Journal of Synchrotron Radiation - August 17, 2017 Category: Physics Authors: Shayduk, R. Pennicard, D. Krausert, K. Gaal, P. Volkov, S. Vonk, V. Hejral, U. Jankowski, M. Reinhardt, M. Leitenberger, W. Stierle, A. Tags: pump – probe X-ray diffraction hybrid pixel X-ray detector triggering timing jitter short communications Source Type: research

In operando quantitation of Li concentration for a commercial Li-ion rechargeable battery using high-energy X-ray Compton scattering
In this study, S-parameter analysis has been applied to a commercial coin cell Li-ion rechargeable battery and the variation of the S-parameters during the charge/discharge cycle at the positive and negative electrodes has been obtained. By using calibration curves for Li composition in the electrodes, the change in Li composition of the positive and negative electrodes has been determined using the S-parameters simultaneously. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - August 17, 2017 Category: Physics Authors: Suzuki, K. Suzuki, A. Ishikawa, T. Itou, M. Yamashige, H. Orikasa, Y. Uchimoto, Y. Sakurai, Y. Sakurai, H. Tags: Li-ion battery in operando measurement quantitation Compton profile research papers Source Type: research

Estimating the absolute flux distribution for a synchrotron X-ray beam using ionization-chamber measurements with various filters
It is shown that an extensive set of accurate ionization-chamber measurements with a primary polychromatic synchrotron X-ray beam transmitted through various filter combinations/thicknesses can be used to quite effectively estimate the absolute flux distribution. The basic technique is simple but the `inversion' of the raw data to extract the flux distribution is a fundamentally ill-posed problem. It is demonstrated, using data collected at the Imaging and Medical Beamline (IMBL) of the Australian Synchrotron, that the absolute flux can be quickly and reliably estimated if a suitable choice of filters is made. Results are ...
Source: Journal of Synchrotron Radiation - August 11, 2017 Category: Physics Authors: Stevenson, A.W. Di Lillo, F. Tags: ionization chambers filters X-ray beam quality harmonic contamination research papers Source Type: research

Confocal depth-resolved fluorescence micro-X-ray absorption spectroscopy for the study of cultural heritage materials: a new mobile endstation at the Beijing Synchrotron Radiation Facility
A confocal fluorescence endstation for depth-resolved micro-X-ray absorption spectroscopy is described. A polycapillary half-lens defines the incident beam path and a second polycapillary half-lens at 90 ° defines the probe sample volume. An automatic alignment program based on an evolutionary algorithm is employed to make the alignment procedure efficient. This depth-resolved system was examined on a general X-ray absorption spectroscopy (XAS) beamline at the Beijing Synchrotron Radiation Facility. Sacrificial red glaze (AD   1368 – 1644) china was studied to show the capability of the instrument. As a mobile ...
Source: Journal of Synchrotron Radiation - August 10, 2017 Category: Physics Authors: Chen, G. Chu, S. Sun, T. Sun, X. Zheng, L. An, P. Zhu, J. Wu, S. Du, Y. Zhang, J. Tags: confocal XAS mobile endstation sacrificial red glaze depth-dependent valence distribution research papers Source Type: research

Characterization of individual stacking faults in a   wurtzite GaAs nanowire by nanobeam X-ray diffraction
Coherent X-ray diffraction was used to measure the type, quantity and the relative distances between stacking faults along the growth direction of two individual wurtzite GaAs nanowires grown by metalorganic vapour epitaxy. The presented approach is based on the general property of the Patterson function, which is the autocorrelation of the electron density as well as the Fourier transformation of the diffracted intensity distribution of an object. Partial Patterson functions were extracted from the diffracted intensity measured along the [000\bar{1}] direction in the vicinity of the wurtzite 00\bar{1}\bar{5} Bragg peak. T...
Source: Journal of Synchrotron Radiation - August 9, 2017 Category: Physics Authors: Davtyan, A. Lehmann, S. Kriegner, D. Zamani, R.R. Dick, K.A. Bahrami, D. Al-Hassan, A. Leake, S.J. Pietsch, U. Hol ý , V. Tags: stacking faults Patterson function nanowire coherent nanobeam X-ray diffraction research papers Source Type: research

The EIGER detector for low-energy electron microscopy and photoemission electron microscopy
EIGER is a single-photon-counting hybrid pixel detector developed at the Paul Scherrer Institut, Switzerland. It is designed for applications at synchrotron light sources with photon energies above 5   keV. Features of EIGER include a small pixel size (75   µ m × 75   µ m), a high frame rate (up to 23   kHz), a small dead-time between frames (down to 3   µ s) and a dynamic range up to 32-bit. In this article, the use of EIGER as a detector for electrons in low-energy electron microscopy (LEEM) and photoemission electron microscopy (PEEM) is reported. It is demonstrated that, with only a mi...
Source: Journal of Synchrotron Radiation - August 9, 2017 Category: Physics Authors: Tinti, G. Marchetto, H. Vaz, C.A.F. Kleibert, A. Andr ä , M. Barten, R. Bergamaschi, A. Br ü ckner, M. Cartier, S. Dinapoli, R. Franz, T. Fr ö jdh, E. Greiffenberg, D. Lopez-Cuenca, C. Mezza, D. Mozzanica, A. Nolting, F. Ramilli, M. Redford, S. Ruat, M Tags: single-photon counters hybrid pixel detectors instrumentation for synchrotron radiation accelerators X-ray detectors PEEM LEEM research papers Source Type: research

Strategies for high-throughput focused-beam ptychography
X-ray ptychography is being utilized for a wide range of imaging experiments with a resolution beyond the limit of the X-ray optics used. Introducing a parameter for the ptychographic resolution gain Gp (the ratio of the beam size over the achieved pixel size in the reconstructed image), strategies for data sampling and for increasing imaging throughput when the specimen is at the focus of an X-ray beam are considered. The tradeoffs between large and small illumination spots are examined. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - August 8, 2017 Category: Physics Authors: Jacobsen, C. Deng, J. Nashed, Y. Tags: ptychography ptychographic resolution gain high throughput short communications Source Type: research

Observation of an optical vortex beam from a helical undulator in the XUV region
The observation of an optical vortex beam at 60   nm wavelength, produced as the second-harmonic radiation from a helical undulator, is reported. The helical wavefront of the optical vortex beam was verified by measuring the interference pattern between the vortex beam from a helical undulator and a normal beam from another undulator. Although the interference patterns were slightly blurred owing to the relatively large electron beam emittance, it was possible to observe the interference features thanks to the helical wavefront of the vortex beam. The experimental results were well reproduced by simulation. (Source: Jour...
Source: Journal of Synchrotron Radiation - August 8, 2017 Category: Physics Authors: Kaneyasu, T. Hikosaka, Y. Fujimoto, M. Iwayama, H. Hosaka, M. Shigemasa, E. Katoh, M. Tags: XUV vortex helical undulator radiation interference research papers Source Type: research

Micro-beam Laue alignment of multi-reflection Bragg coherent diffraction imaging measurements
Multi-reflection Bragg coherent diffraction imaging has the potential to allow three-dimensional (3D) resolved measurements of the full lattice strain tensor in specific micro-crystals. Until now such measurements were hampered by the need for laborious, time-intensive alignment procedures. Here a different approach is demonstrated, using micro-beam Laue X-ray diffraction to first determine the lattice orientation of the micro-crystal. This information is then used to rapidly align coherent diffraction measurements of three or more reflections from the crystal. Based on these, 3D strain and stress fields in the crystal are...
Source: Journal of Synchrotron Radiation - August 8, 2017 Category: Physics Authors: Hofmann, F. Phillips, N.W. Harder, R.J. Liu, W. Clark, J.N. Robinson, I.K. Abbey, B. Tags: Bragg coherent diffraction imaging micro-beam Laue diffraction ion implantation strain tensor measurement research papers Source Type: research

Flyscan opportunities in medicine: the case of quantum rattle based on gold quantum dots
This study presents a complete set of data acquired after injection of gold-cluster-enriched mesoporous silica nanospheres, used as potential theranostic vectors, into rats. While classical X-ray fluorescence investigations (using step-by-step acquisitions) are based on a limited number of samples (approximately one per day at the DiffAbs beamline), the Flyscan mode has enabled gathering information on the interaction of nanometer-scale vectors in different organs such as liver, spleen and kidney at the micrometer scale, for five rats, in only a single five-day synchrotron shift. Moreover, numerous X-ray absorption near-ed...
Source: Journal of Synchrotron Radiation - August 7, 2017 Category: Physics Authors: Esteve, E. Reguer, S. Boissiere, C. Chaneac, C. Lugo, G. Jouanneau, C. Mocuta, C. Thiaudiere, D. Leclercq, N. Leyh, B. Greisch, J.-F. Berthault, J. Daudon, M. Ronco, P. Bazin, D. Tags: Flyscan method theranostic vectors gold-cluster-enriched mesoporous silica nanospheres X-ray fluorescence XANES research papers Source Type: research

Electron-bunch lengthening on higher-harmonic oscillations in storage-ring free-electron lasers
The influence of higher-harmonic free-electron laser (FEL) oscillations on an electron beam have been studied by measuring its bunch length at the NIJI-IV storage ring. The bunch length and the lifetime of the electron beam were measured, and were observed to have become longer owing to harmonic lasing, which is in accord with the increase of the FEL gain. It was demonstrated that the saturated FEL power could be described by the theory of bunch heating, even for the harmonic lasing. Cavity-length detuning curves were measured for the harmonic lasing, and it was found that the width of the detuning curve was proportional t...
Source: Journal of Synchrotron Radiation - August 7, 2017 Category: Physics Authors: Sei, N. Ogawa, H. Okuda, S. Tags: free-electron laser higher-harmonic oscillation bunch length detuning curve research papers Source Type: research

Analysis of the microvascular morphology and hemodynamics of breast cancer in mice using SPring-8 synchrotron radiation microangiography
In this study, mice bearing the human breast cancer cell lines MDAMB231 and NOTCH4 overexpression in MDAMB231 (MDAMB231NOTCH4+) and normal mice were assessed using SR microangiography. NOTCH is transmembrane protein that has crucial roles for vasculogenesis, angiogenesis and tumorigenesis, and NOTCH4 is considered to be a cause of high-flow arteriovenous shunting. A subgroup of mice received intravenous eribulin treatment, which is known to improve intratumor core circulation (MDAMB231_eribulin). Microvessel branches from approximately 200   µ m to less than 20   µ m in diameter were observed within the sam...
Source: Journal of Synchrotron Radiation - August 2, 2017 Category: Physics Authors: Torii, M. Fukui, T. Inoue, M. Kanao, S. Umetani, K. Shirai, M. Inagaki, T. Tsuchimochi, H. Pearson, J.T. Toi, M. Tags: tumor microvessels hemodynamics quantitative analysis SR microangiography research papers Source Type: research