Transmission measurement at the Bernina branch of the Aramis Beamline of SwissFEL
The transmission of the optical components of the Bernina branch of the Aramis beamline at SwissFEL has been measured with an X-ray gas monitor from DESY and compared with a PSI gas detector upstream of the optical components. The transmission efficiencies of the Mo, Si and SiC mirror coatings of the Aramis beamline and the various other in-beam components were evaluated and compared with theoretical calculations, showing an agreement of 6% or better in all cases. The experiment has also shown the efficacy of the high-harmonic rejection mirrors at the Bernina branch of the Aramis beamline at   SwissFEL, and characteri...
Source: Journal of Synchrotron Radiation - October 22, 2019 Category: Physics Authors: Juranic, P. Tiedtke, K. Owada, S. Tanaka, T. Jastrow, U. Sorokin, A. Patthey, L. Mankowsky, R. Degenhardt, M. Arbelo, Y. Arrell, C. Smedley, J. Bohon, J. Follath, R. Tags: instrumentation performance XFEL beamlines Source Type: research

Phase-space matching between bent Laue and flat Bragg crystals
Through phase-space analysis of Dumond diagrams for a flat Bragg crystal, a single bent Laue crystal and a monochromator consisting of double-bent Laue crystals, this work shows that it is possible to match the flat Bragg crystal to both the single-crystal and double-crystal Laue monochromators. The matched system has the advantage that the phase space of the bent crystal's output beam is much larger than that of the flat crystal, making the combined system stable. Here it is suggested that such a matched system can be used at synchrotron facilities to realize X-ray dark-field imaging, analyzer-based imaging and diffractio...
Source: Journal of Synchrotron Radiation - October 22, 2019 Category: Physics Authors: Zhong, Z. Hasnah, M. Broadbent, A. Dooryhee, E. Lucas, M. Tags: bent Laue crystals Dumond diagram phase-contrast imaging analyser-based imaging diffraction-enhanced imaging monochromator analyzers phase space high-energy X-rays research papers Source Type: research

Improved calibration of area detectors using multiple placements
Calibration of area detectors from powder diffraction standards is widely used at synchrotron beamlines. From a single diffraction image, it is not possible to determine both the sample-to-detector distance and the wavelength, but, with images taken from multiple positions along the beam direction and where the relative displacement is known, the sample-to-detector distance and wavelength can both be determined with good precision. An example calibration using the GSAS-II software package is presented. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - October 22, 2019 Category: Physics Authors: Horn, C. Ginell, K.M. Von Dreele, R.B. Yakovenko, A.A. Toby, B.H. Tags: calibration area detection powder diffraction research papers Source Type: research

Confined-walking mode for an elliptical polarized undulator and its application
Elliptical polarized undulators (EPUs) are broadly used in the soft X-ray energy range. They have the advantage of providing photons with both varied energy and polarization through adjustments to the value of the gap and/or shift magnet arrays in an undulator. Yet these adjustments may create e disturbance on the stability of the electron beam in a storage ring. To correct such a disturbance, it is necessary to establish a feed-forward table of key nodes in the gap-shift-defined two-dimensional parameter space. Such a table can only be scanned during machine-study time. For a free-walking mode, whereby an undulator is all...
Source: Journal of Synchrotron Radiation - October 22, 2019 Category: Physics Authors: Zou, Y. Zhang, Q. Zhang, J. Zhuo, J. Jiang, G. Liu, P. Jiang, B. Zheng, L. Zhou, Q. Yin, L. Wang, Y. Tai, R. Tags: elliptical polarized undulators magnet array gaps magnet array shifts reduced set of key nodes free-walking mode confined-walking mode research papers Source Type: research

Upgrade of laser pump time-resolved X-ray probes in Beijing synchrotron
The upgrade of the laser pump time-resolved X-ray probes, namely time-resolved X-ray absorption spectroscopy (TR-XAS) and X-ray diffraction (TR-XRD), implemented at the Beijing Synchrotron Radiation Facility, is described. The improvements include a superbunch fill, a high-efficiency fluorescence collection, an efficient spatial overlap protocol and a new data-acquisition scheme. After upgrade, the adequate TR-XAS signal is now obtained in a 0.3   mM solution, compared with a 6   mM solution in our previous report. Furthermore, to extend application in photophysics, the TR-XAS probe is applied on SrCoO2.5 thin film. An...
Source: Journal of Synchrotron Radiation - October 21, 2019 Category: Physics Authors: Yu, C. Zhang, Y. Lei, G. Wang, H. Wang, Y.- Zhang, B.-B. Sun, D.-R. Zhao, J.-L. Zhou, Y.-F. Li, Q.-J. Gao, Z.- Zhan, F. Tao, Y. Tags: laser pump/X-ray probe time-resolved X-ray absorption spectroscopy time-resolved X-ray diffraction thin films beamlines Source Type: research

Time-resolved X-ray absorption spectroelectrochemistry of redox active species in solution
We describe here the development and operation of a new spectroelectrochemical transmission cell for time-resolved X-ray absorption spectroscopy of solutions. X-ray absorption spectra were recorded on the ROCK beamline of SOLEIL under constant and scanning potentials. Spectra were recorded at a frequency of 2   Hz during a cyclic voltammetry experiment performed on a 20   mM solution of FeIIICl3 · 6H2O at 20   mV   s − 1 scanning speed. Spectra with good signal-to-noise ratios were obtained when averaging ten spectra over 5   s, corresponding to a 100   mV potential range. A 90% conversion rate fro...
Source: Journal of Synchrotron Radiation - October 21, 2019 Category: Physics Authors: Cheaib, K. Maurice, B. Mateo, T. Halime, Z. Lassalle-Kaiser, B. Tags: time-resolved X-ray absorption spectroscopy cyclic voltammetry redox reactions research papers Source Type: research

Light source based on a 100   mm-long monolithic undulator magnet with a very short 4   mm-period length
A novel method to fabricate undulator magnets of a-few-millimetre-period length is being explored. Plate-type magnets, 100   mm-long with 4   mm-period length, have been successfully fabricated. They produce an undulator field of approximately 3   kG at a gap of 1.6   mm. Prototype undulators based on this technology have been constructed. Field measurements and characterization show that the quality of the undulator field of these plate magnets is sufficient for an undulator light source, and the calculated spectrum shows that the fundamental radiation emitted from this field is quite satisfactory. Test experiment...
Source: Journal of Synchrotron Radiation - October 21, 2019 Category: Physics Authors: Yamamoto, S. Kashiwagi, S. Masuda, S. Nakanii, N. Hosokai, T. Kando, M. Muto, T. Nanbu, K. Hinode, F. Hama, H. Tags: synchrotron light source undulator very short period length research papers Source Type: research

Multi-element effects on arsenate accumulation in a geochemical matrix determined using µ -XRF, µ -XANES and spatial statistics
The objective of this work was to develop approaches for assessing effects of co-localized geochemical matrix elements on the accumulation and chemical speciation of arsenate applied to a soil matrix. Synchrotron X-ray fluorescence microprobe ( µ -XRF) images collected across 100   µ m × 100   µ m and 10   µ m × 10   µ m regions of a naturally weathered soil sand-grain coating before and after treatment with As(V) solution showed strong positive partial correlations (r ′ = 0.77 and 0.64, respectively) between accumulated As and soil Fe, with weaker partial correlation...
Source: Journal of Synchrotron Radiation - October 21, 2019 Category: Physics Authors: Sharma, A. Muyskens, A. Guinness, J. Polizzotto, M. Fuentes, M. Tappero, R. Chen-Wiegart, Y.- Thieme, J. Williams, G. Acerbo, A. Hesterberg, D. Tags: reactive microsites multi-component complexity arsenic partial correlation spatial regression research papers Source Type: research

The TES beamline (8-BM) at NSLS-II: tender-energy spatially resolved X-ray absorption spectroscopy and X-ray fluorescence imaging
The tender-energy X-ray spectroscopy (TES) beamline at the National Synchrotron Light Source II (NSLS-II) is now operational for general users. Its scientific mission includes static and in situ X-ray fluorescence imaging and spatially resolved X-ray absorption spectroscopy for characterization of complex heterogeneous, structured and dynamic natural or engineered materials and systems. TES is optimized for the tender-energy range, offering routine operations from 2.0 to 5.5   keV, with capabilities to reach down to 1.2 or up to 8   keV with configuration change. TES is designed as an extended X-ray absorption fine-str...
Source: Journal of Synchrotron Radiation - October 17, 2019 Category: Physics Authors: Northrup, P. Tags: tender energy microbeam XAS in situ XAS XRF microprobes XANES EXAFS NSLS-II beamlines Source Type: research

Micro-focused MHz pink beam for time-resolved X-ray emission spectroscopy
The full radiation from the first harmonic of a synchrotron undulator (between 5 and 12   keV) at the Advanced Photon Source is microfocused using a stack of beryllium compound refractive lenses onto a fast-moving liquid jet and overlapped with a high-repetition-rate optical laser. This micro-focused geometry is used to perform efficient nonresonant X-ray emission spectroscopy on transient species using a dispersive spectrometer geometry. The overall usable flux achieved on target is above 1015   photons   s − 1 at 8   keV, enabling photoexcited systems in the liquid phase to be tracked with time resolutions ...
Source: Journal of Synchrotron Radiation - October 17, 2019 Category: Physics Authors: Tu, M.-F. Doumy, G. Al Haddad, A. March, A.M. Southworth, S.H. Assoufid, L. Kumagai, Y. Walko, D.A. DiChiara, A.D. Liu, Z. Shi, B. Young, L. Bostedt, C. Tags: X-ray emission spectroscopy time-resolved pump/probe synchrotron beryllium lenses solution dynamics MHz repetition rate research papers Source Type: research

A hierarchical approach for modeling X-ray beamlines: application to a coherent beamline
Different approaches to simulate a modern X-ray beamline are considered. Several methodologies with increasing complexity are applied to discuss the relevant parameters that quantify the beamline performance. Parameters such as flux, dimensions and intensity distribution of the focused beam, and coherence properties are obtained from simple analytical calculations to sophisticated computer simulations using ray-tracing and wave optics techniques. A latest-generation X-ray nanofocusing beamline for coherent applications (ID16A at the ESRF) has been chosen to study in detail the issues related to highly demagnifying synchrot...
Source: Journal of Synchrotron Radiation - October 17, 2019 Category: Physics Authors: Sanchez del Rio, M. Celestre, R. Glass, M. Pirro, G. Herrera, J.R. Barrett, R. da Silva, J.C. Cloetens, P. Shi, X. Rebuffi, L. Tags: beamline simulations research papers Source Type: research

Local atomic structure analysis of GaN surfaces via X-ray absorption spectroscopy by detecting Auger electrons with low energies
GaN is a promising material for power semiconductor devices used in next-generation vehicles. Its electrical properties such as carrier mobility and threshold voltage are affected by the interface between the oxide and the semiconductor, and identifying the interface states is important to improve these properties. A surface-sensitive measurement of Ga K-edge extended X-ray absorption fine structure (EXAFS) by detecting Ga LMM Auger electrons that originate from Ga K-shell absorption is proposed for GaN. LMM Auger electrons with low energies were detected and the EXAFS oscillation was confirmed, providing information on th...
Source: Journal of Synchrotron Radiation - October 15, 2019 Category: Physics Authors: Isomura, N. Kikuta, D. Takahashi, N. Kosaka, S. Kataoka, K. Tags: extended X-ray absorption fine structure Auger electron yields surface sensitivity gallium nitride K-shell absorption research papers Source Type: research

Performance of nearly fixed offset asymmetric channel-cut crystals for X-ray monochromators
X-ray double-crystal monochromators face a shift of the exit beam when the Bragg angle and thus the transmitted photon energy changes. This can be compensated for by moving one or both crystals accordingly. In the case of monolithic channel-cut crystals, which exhibit utmost stability, the shift of the monochromated beam is inevitable. Here we report performance tests of novel, asymmetrically cut, channel-cut crystals which reduce the beam movements by more than a factor of 20 relative to the symmetric case over the typical energy range of an EXAFS spectrum at the Cu K-edge. In addition, the presented formulas for the beam...
Source: Journal of Synchrotron Radiation - October 15, 2019 Category: Physics Authors: Frahm, R. Diao, Q. Murzin, V. Bornmann, B. L ü tzenkirchen-Hecht, D. Hong, Z. Li, T. Tags: X-ray monochromator double-crystal monochromators asymmetric geometry silicon crystals QEXAFS time-resolved spectroscopy synchrotron instrumentation X-ray absorption spectroscopy research papers Source Type: research

An enlightening procedure to explain the extreme power of synchrotron radiation
A simple approach exploits quantum properties to justify the dependence on γ 4 of the total synchrotron emitted power. It also clarifies some apparent puzzles and brings to light the underlying, multiple relativistic phenomena. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - October 9, 2019 Category: Physics Authors: Margaritondo, G. Tags: Doppler relativity photon Einstein synchrotron radiation X-rays teaching and education Source Type: research

X-ray mirror figure correction by differential deposition and off-line metrology
The surface figure error of a hard X-ray mirror was improved by combining differential deposition and off-line metrology tools. Thin Cr layers were deposited on flat substrates by DC magnetron sputtering. The substrates were moved in front of a beam-defining aperture. The required velocity profile was calculated using a deconvolution algorithm. The Cr thickness profiles were measured directly using hard X-ray reflectivity data. The surface figure was characterized using conventional visible-light metrology instrumentation (long trace profiler) before and after the deposition. The method converges quickly, and after two ite...
Source: Journal of Synchrotron Radiation - October 9, 2019 Category: Physics Authors: Morawe, C. Labour é , S. Peffen, J.-C. Perrin, F. Vivo, A. Barrett, R. Tags: X-ray optics figure corrections differential depositions off-line metrology magnetron sputtering research papers Source Type: research

Investigation of (micro-)meteoritic materials at the new hard X-ray imaging PUMA beamline for heritage sciences
At the French synchrotron facility SOLEIL, a new X-ray imaging facility PUMA (Photons Utilis é s pour les Mat é riaux Anciens) has been made available to scientific communities studying materials from cultural heritage. This new instrument aims to achieve 2D and 3D imaging with microscopic resolution, applying different analytical techniques including X-ray fluorescence spectroscopy (XRF), X-ray absorption spectroscopy (XAS), X-ray diffraction and phase-contrast imaging. In order to discover its capabilities a detailed analytical characterization of this beamline as an analytical and imaging tool is deemed ne...
Source: Journal of Synchrotron Radiation - October 9, 2019 Category: Physics Authors: Tack, P. Bazi, B. Vekemans, B. Okbinoglu, T. Van Maldeghem, F. Goderis, S. Sch ö der, S. Vincze, L. Tags: PUMA confocal XRF XANES differential imaging cultural heritage micrometeorite pallasite research papers Source Type: research

Determination of X-ray pulse duration via intensity correlation measurements of X-ray fluorescence
A simple method using X-ray fluorescence is proposed to diagnose the duration of an X-ray free-electron laser (XFEL) pulse. This work shows that the degree of intensity correlation of the X-ray fluorescence generated by irradiating an XFEL pulse on metal foil reflects the magnitude relation between the XFEL duration and the coherence time of the fluorescence. Through intensity correlation measurements of copper K α fluorescence, the duration of 12   keV XFEL pulses from SACLA was evaluated to be ∼ 10   fs. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - September 22, 2019 Category: Physics Authors: Inoue, I. Tamasaku, K. Osaka, T. Inubushi, Y. Yabashi, M. Tags: X-ray free-electron lasers intensity correlation X-ray fluorescence short communications Source Type: research

Gold nano-mesh synthesis by continuous-flow X-ray irradiation
X-ray irradiation has been extensively used in recent years as a fabrication step for nanoparticles and nanoparticle systems. A variant of this technique, continuous-flow X-ray irradiation, has recently been developed, and offers three important advantages: precise control of the irradiation dose, elimination of convection effects in the precursor solution, and suitability for large-scale production. Here, the use of this method to fabricate Au nano-meshes of interest as transparent and flexible electrodes for optoelectronics is reported. The study includes extensive characterization of the synthesis parameters and of the ...
Source: Journal of Synchrotron Radiation - September 22, 2019 Category: Physics Authors: Li, M.-T. Lai, S.-F. Yang, S.-M. Chen, Y.-S. Chen, Y.-J. Tok, E.S. Margaritondo, G. Hwu, Y. Tags: nanoparticle synthesis X-ray irradiation gold nano-mesh transparent conductive electrodes optoelectronics research papers Source Type: research

Controllability of cupric particle synthesis by linear alcohol chain number as additive and pH control in cupric acetate solution using X-ray radiolysis
This study may open a door to understanding and investigating a novel photochemical reaction route induced under X-ray irradiation. The development of the X-ray radiolysis process enables us to achieve the rapid and easy process of synthesis and immobilization of higher-order nano/microstructure consisting of various materials. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - September 11, 2019 Category: Physics Authors: Yamaguchi, A. Okada, I. Sakurai, I. Izumi, H. Ishihara, M. Fukuoka, T. Suzuki, S. Elphick, K. Jackson, E. Hirohata, A. Utsumi, Y. Tags: X-ray radiolysis cupric particle alkyl alcohol pH control three-dimensional additive manufacturing research papers Source Type: research

Grazing-angle reflectivity setup for the low-temperature infrared spectroscopy of two-dimensional systems
A new optical setup is described that allows the reflectivity at grazing incidence to be measured, including ultrathin films and two-dimensional electron systems (2DES) down to liquid-helium temperatures, by exploiting the Berreman effect and the high brilliance of infrared synchrotron radiation. This apparatus is well adapted to detect the absorption of a 2DES of nanometric thickness, namely that which forms spontaneously at the interface between a thin film of LaAlO3 and its SrTiO3 substrate, and to determine its Drude parameters. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - September 10, 2019 Category: Physics Authors: Verseils, M. Voute, A. Langerome, B. Deutsch, M. Brubach, J.-B. Kalaboukhov, A. Nucara, A. Calvani, P. Roy, P. Tags: infrared grazing-angle reflectivity low-temperature two-dimensional systems research papers Source Type: research

Optimization of a phase-space beam position and size monitor for low-emittance light sources
The recently developed vertical phase-space beam position and size monitor (ps-BPM) system has proven to be able to measure the electron-source position, angle, size and divergence simultaneously in the vertical plane at a single location of a beamline. The optimization of the ps-BPM system is performed by ray-tracing simulation to maximize the instrument sensitivity and resolution. The contribution of each element is studied, including the monochromator, the K-edge filter, the detector and the source-to-detector distance. An optimized system is proposed for diffraction-limited storage rings, such as the Advanced Photon So...
Source: Journal of Synchrotron Radiation - September 10, 2019 Category: Physics Authors: Samadi, N. Shi, X. Chapman, D. Tags: beam position and size monitor phase space diagnostics and feedback ray-tracing simulation diffraction-limited storage rings research papers Source Type: research

Comparison of high-resolution synchrotron-radiation-based phase-contrast imaging and absorption-contrast imaging for evaluating microstructure of vascular networks in rat brain: from 2D to 3D views
In conclusion, SR-based phase-contrast imaging holds great promise for visualizing microstructure of microvascular networks in two- and three-dimensional perspectives during the development of neurovascular diseases. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - September 10, 2019 Category: Physics Authors: Li, H. Ding, H. Yin, X. Chen, Z. Tang, B. Sun, J. Hu, X. Lv, X. Kang, S. Fan, Y. Wu, T. Zhao, S. Xiao, B. Zhang, M. Tags: 2D 3D brain microtomography synchrotron radiation vascular network research papers Source Type: research

Comparative analysis of sample preparation protocols of soft biological tissues for morphometric studies using synchrotron-based X-ray microtomography
The spread of microtomography as a tool for visualization of soft tissues has had a significant impact on a better understanding of complex biological systems. This technique allows a detailed three-dimensional quantitative view of the specimen to be obtained, correlating its morphological organization with its function, providing valuable insights on the functionality of the tissue. Regularly overlooked, but of great importance, proper sample mounting and preparation are fundamental for achieving the highest possible image quality even for the high-resolution imaging systems currently under development. Here, a quantitati...
Source: Journal of Synchrotron Radiation - September 9, 2019 Category: Physics Authors: Dias, C.S.B. Neto, D.P.A. Baraldi, G.L. Fonseca, M.C. Tags: microtomography soft tissues mounting synchrotron radiation research papers Source Type: research

In situ depth-resolved synchrotron radiation X-ray spectroscopy study of radiation-induced Au deposition
To illustrate the process of synchrotron radiation induced reduction of tetrachloroauric solutions, a confocal synchrotron radiation X-ray spectroscopy experiments system has been introduced to monitor the depth-resolved elemental Au distribution and chemical species during the Au reduction reaction. Combining the results from confocal X-ray spectroscopy with that from X-ray contrast imaging, the mechanism of synchrotron radiation induced Au reduction, along with the process of Au deposition, were proposed. These demonstrations provide novel avenues to spatially resolved analysis of in situ solution radiolysis. (Source: Jo...
Source: Journal of Synchrotron Radiation - September 9, 2019 Category: Physics Authors: Chen, G. Du, Y. An, P. Zheng, L. Chu, S. Zhang, J. Tags: radiation-induced reduction confocal optic systems micro-X-ray fluorescence XANES deposition processes research papers Source Type: research

Thickness of carbon coatings on silicon materials determined by hard X-ray photoelectron spectroscopy at multiple photon energies
Hard X-ray photoelectron spectroscopy at multiple photon energies is used to investigate the surface structure of carbon coatings on silicon materials destined for use as negative electrodes in lithium-ion batteries. The photoelectron intensity from the carbon coatings decreases with an increase in the kinetic energy of the photoelectron. By fitting the photoelectron intensity versus energy to numerically derived curves, the thickness and coverage of the carbon coatings can be obtained. The results are in agreement with the values suggested by the cross-sectional secondary-electron microscopy images of the carbon coatings,...
Source: Journal of Synchrotron Radiation - September 9, 2019 Category: Physics Authors: Isomura, N. Takahashi, N. Kosaka, S. Kawaura, H. Tags: hard X-ray photoelectron spectroscopy (HAXPES) lithium-ion battery (LIB) silicon negative electrodes layered polysilane carbon coating research papers Source Type: research

Linear array detector for online diagnostics of spectral distributions at MHz repetition rates
Free-electron lasers (FELs) based on superconducting accelerator technology and storage ring facilities operate with bunch repetition rates in the MHz range, and the need arises for bunch-by-bunch electron and photon diagnostics. For photon-pulse-resolved measurements of spectral distributions, fast one-dimensional profile monitors are required. The linear array detector KALYPSO (KArlsruhe Linear arraY detector for MHz-rePetition rate SpectrOscopy) has been developed for electron bunch or photon pulse synchronous read-out with frame rates of up to 2.7   MHz. At the FLASH facility at DESY, a current version of KALYPSO wit...
Source: Journal of Synchrotron Radiation - August 31, 2019 Category: Physics Authors: Gerth, C. Brenner, G. Caselle, M. D ü sterer, S. Haack, D. Makowski, D. Mielczarek, A. Palutke, S. Rota, L. Rybnikov, V. Schmidt, C. Steffen, B. Tiedtke, K. Tags: linear array detector line scan camera high repetition rate diagnostics free-electron laser extreme ultraviolet radiation soft X-ray spectroscopy research papers Source Type: research

BioStruct-Africa: empowering Africa-based scientists through structural biology knowledge transfer and mentoring – recent advances and future perspectives
Being able to visualize biology at the molecular level is essential for our understanding of the world. A structural biology approach reveals the molecular basis of disease processes and can guide the design of new drugs as well as aid in the optimization of existing medicines. However, due to the lack of a synchrotron light source, adequate infrastructure, skilled persons and incentives for scientists in addition to limited financial support, the majority of countries across the African continent do not conduct structural biology research. Nevertheless, with technological advances such as robotic protein crystallization a...
Source: Journal of Synchrotron Radiation - August 27, 2019 Category: Physics Authors: Nji, E. Traore, D.A.K. Ndi, M. Joko, C.A. Doyle, D.A. Tags: BioStruct-Africa structural biology neglected tropical diseases capacity building synchrotron remote data collection African Light Source teaching and education Source Type: research

Coherent Bragg imaging of 60   nm Au nanoparticles under electrochemical control at the NanoMAX beamline
Nanoparticles are essential electrocatalysts in chemical production, water treatment and energy conversion, but engineering efficient and specific catalysts requires understanding complex structure – reactivity relations. Recent experiments have shown that Bragg coherent diffraction imaging might be a powerful tool in this regard. The technique provides three-dimensional lattice strain fields from which surface reactivity maps can be inferred. However, all experiments published so far have investigated particles an order of magnitude larger than those used in practical applications. Studying smaller particles quickly...
Source: Journal of Synchrotron Radiation - August 26, 2019 Category: Physics Authors: Bj ö rling, A. Carbone, D. Sarabia, F.J. Hammarberg, S. Feliu, J.M. Solla-Gull ó n, J. Tags: coherent diffraction imaging nanodiffraction electrocatalysis short communications Source Type: research

Laser-slicing at a low-emittance storage ring
Laser-slicing at a diffraction-limited storage ring light source in the soft X-ray region is investigated with theoretical and numerical modelling. It turns out that the slicing efficiency is favoured by the ultra-low beam emittance, and that slicing can be implemented without interference to the standard multi-bunch operation. Spatial and spectral separation of the sub-picosecond radiation pulse from a hundreds of picosecond-long background is achieved by virtue of 1:1 imaging of the radiation source. The spectral separation is enhanced when the radiator is a transverse gradient undulator. The proposed configuration appli...
Source: Journal of Synchrotron Radiation - August 26, 2019 Category: Physics Authors: Di Mitri, S. Barletta, W. Bianco, A. Cudin, I. Diviacco, B. Raimondi, L. Spampinati, S. Spezzani, C. Masciovecchio, C. Tags: storage ring diffraction limit laser slicing undulator radiation synchrotron light source radiation background research papers Source Type: research

A versatile nanoreactor for complementary in situ X-ray and electron microscopy studies in catalysis and materials science
Two in situ `nanoreactors' for high-resolution imaging of catalysts have been designed and applied at the hard X-ray nanoprobe endstation at beamline P06 of the PETRA III synchrotron radiation source. The reactors house samples supported on commercial MEMS chips, and were applied for complementary hard X-ray ptychography (23   nm spatial resolution) and transmission electron microscopy, with additional X-ray fluorescence measurements. The reactors allow pressures of 100   kPa and temperatures of up to 1573   K, offering a wide range of conditions relevant for catalysis. Ptychographic tomography was demonstrated at li...
Source: Journal of Synchrotron Radiation - August 26, 2019 Category: Physics Authors: Fam, Y. Sheppard, T.L. Becher, J. Scherhaufer, D. Lambach, H. Kulkarni, S. Keller, T.F. Wittstock, A. Wittwer, F. Seyrich, M. Brueckner, D. Kahnt, M. Yang, X. Schropp, A. Stierle, A. Schroer, C.G. Grunwaldt, J.-D. Tags: porous nanoreactors catalysis X-ray microscopy electron microscopy hard X-ray ptychography research papers Source Type: research

A micro channel-cut crystal X-ray monochromator for a self-seeded hard X-ray free-electron laser
A channel-cut Si(111) crystal with a channel width of 90   µ m was developed for achieving reflection self-seeding in hard X-ray free-electron lasers (XFELs). With the crystal a monochromatic seed pulse is produced from a broadband XFEL pulse generated in the first undulator section with an optical delay of 119   fs at 10   keV. The small optical delay allows a temporal overlap between the seed optical pulse and the electron bunch by using a small magnetic chicane for the electron beam placed between two undulator sections. Peak reflectivity reached 67%, which is reasonable compared with the theoretical value o...
Source: Journal of Synchrotron Radiation - August 26, 2019 Category: Physics Authors: Osaka, T. Inoue, I. Kinjo, R. Hirano, T. Morioka, Y. Sano, Y. Yamauchi, K. Yabashi, M. Tags: XFELs self-seeding channel-cut crystals research papers Source Type: research

High-pressure nuclear inelastic scattering with backscattering monochromatization
The capability to perform high-pressure low-temperature nuclear inelastic scattering on 125Te and 121Sb with a sapphire backscattering monochromator is presented. This technique was applied to measure nuclear inelastic scattering in TeO2 at pressures up to 10   GPa and temperatures down to 25   K. The evaluated partial Te densities of phonon states were compared with theoretical calculations and with Raman scattering measured under the same conditions. The high-pressure cell developed in this work can also be used for other techniques at pressures up to at least 100   GPa. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - August 22, 2019 Category: Physics Authors: Sergueev, I. Glazyrin, K. Herrmann, M.G. Alexeev, P. Wille, H.-C. Leupold, O. May, A.F. Pandey, T. Lindsay, L.R. Friese, K. Hermann, R.P. Tags: nuclear inelastic scattering high pressure backscattering nuclear resonance scattering density of phonon states research papers Source Type: research

On the advantages of operation in second-order diffraction of blazed gratings in soft X-ray monochromators
This study will thus address the feasibility of efficient diffraction of soft X-rays in the second order at reflection gratings when operated at grazing angles of incidence. The related systematic study could make profitable use of a recently introduced simple analytical equation for the prediction of the diffraction efficiency of blazed gratings with an ideal sawtooth profile. The predictions are then verified by use of rigorous calculations. The principle finding is that, by operation of gratings with lower groove densities, and thus with higher efficiencies, in higher order diffraction, one can extend the tuning in exis...
Source: Journal of Synchrotron Radiation - August 22, 2019 Category: Physics Authors: Jark, W. Tags: diffraction grating soft X-rays diffraction efficiency second-order diffraction soft X-ray monochromator research papers Source Type: research

High-efficiency fast X-ray imaging detector development at SSRF
Indirect X-ray imaging detectors consisting of scintillator screens, long-working-distance microscope lenses and scientific high-speed complementary metal-oxide semiconductor (CMOS) cameras are usually used to realize fast X-ray imaging with white-beam synchrotron radiation. However, the detector efficiency is limited by the coupling efficiency of the long-working-distance microscope lenses, which is only about 5%. A long-working-distance microscope lenses system with a large numerical aperture (NA) is designed to increase the coupling efficiency. It offers an NA of 0.5 at 8 × magnification. The Mitutoyo long-working...
Source: Journal of Synchrotron Radiation - August 22, 2019 Category: Physics Authors: Xie, H. Luo, H. Du, G. Zhao, C. Xu, W. Zhou, G. Chen, R. Xiao, T. Tags: scintillators indirect X-ray imaging detectors long-working-distance microscope lenses fast X-ray imaging fast X-ray microtomography CMOS cameras dynamic X-ray micro-CT synchrotron radiation research papers Source Type: research

Soldering of silicon to Invar for double-crystal monochromators
At the Brazilian Synchrotron Light Laboratory (LNLS), new double-crystal monochromators are under development for use at the new Brazilian fourth-generation synchrotron, Sirius. The soldering technique used for the double-crystal monochromators ensures the union of monocrystalline silicon with FeNi alloy, Invar36 (64Fe – 36Ni) from Grupo Metal and Invar39 (61Fe – 39Fe) from Scientific Alloys, through SnSb (92.8Sn – 7.2Sb), SnCu (Sn – 0.3Cu) and SnBiCu (Sn – 1.4Bi – 0.7Cu) alloys from Nihon Superior. Following soldering tests and quantitative analysis, the Invar39/SnBiCu/Si samples were s...
Source: Journal of Synchrotron Radiation - August 22, 2019 Category: Physics Authors: Auricchio, M.M.B. Mei, P.R. Bagnato, O.R. Tags: soldering silicon Invar interface alloy research papers Source Type: research

A novel method for measuring the focal point of a   sagittal-focusing Laue crystal monochromator
In order to overcome space limitations, a novel method is introduced to measure the focal point size of a sagittally bent Laue crystal monochromator by using a multi-hole array. Combined with ray-tracing measurements, the focal length and focused beam size were determined. Theoretical simulations and experiments were performed to demonstrate the feasibility of this method. The experimental results show that this method can provide a fast way of measuring the focusing characteristics of a sagittally bent Laue crystal monochromator. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - August 19, 2019 Category: Physics Authors: Yang, J. Sheng, W. Liu, X. Hu, L. Cai, Q. Tags: sagittally bent double-Laue monochromator focal point size multi-hole arrays ray-tracing measurements short communications Source Type: research

Microsecond time-resolved X-ray diffraction for the investigation of fatigue behavior during ultrasonic fatigue loading
A new method based on time-resolved X-ray diffraction is proposed in order to measure the elastic strain and stress during ultrasonic fatigue loading experiments. Pure Cu was chosen as an example material for the experiments using a 20   kHz ultrasonic fatigue machine mounted on the six-circle diffractometer available at the DiffAbs beamline on the SOLEIL synchrotron facility in France. A two-dimensional hybrid pixel X-ray detector (XPAD3.2) was triggered by the strain gage signal in a synchronous data acquisition scheme (pump – probe-like). The method enables studying loading cycles with a period of 50   µ...
Source: Journal of Synchrotron Radiation - August 19, 2019 Category: Physics Authors: Ors, T. Ranc, N. Pelerin, M. Michel, V. Favier, V. Castelnau, O. Mocuta, C. Thiaudi è re, D. Tags: ultrasonic fatigue tests very high cycle fatigue time-resolved stress measurement laser extensometry X-ray diffraction research papers Source Type: research

Investigation of the local structure of molten ThF4 – LiF and ThF4 – LiF – BeF2 mixtures by high-temperature X-ray absorption spectroscopy and molecular-dynamics simulation
The microscopic structures of ThF4 – LiF and ThF4 – LiF – BeF2 molten salts have been systematically investigated by in situ high-temperature X-ray absorption fine-structure (XAFS) spectroscopy combined with molecular-dynamics (MD) simulations. The results reveal that the local structure of thorium ions was much more disordered in the molten state of the ThF4 – LiF – BeF2 salt than that in ThF4 – LiF, implying that the Th and F ions were exchanged more frequently in the presence of Be ions. The structures of medium-range-ordered coordination shells (such as Th – F2nd and Th –...
Source: Journal of Synchrotron Radiation - August 19, 2019 Category: Physics Authors: Sun, J. Guo, X. Zhou, J. Dai, J. Song, S. Bao, H. Lin, J. Yu, H. He, S. Jiang, F. Long, D. Zhang, L. Wang, J.-Q. Tags: fluoride salts molecular dynamics simulations in situ XAFS medium-range-ordered structure transport properties research papers Source Type: research

Focal shift induced by source displacements and optical figure errors
In this work the longitudinal shifts of the focal plane of an ellipsoidal mirror induced by longitudinal shifts of the source and by the optical figure error of the mirror itself are investigated. The case of an ideal mirror illuminated by a Gaussian beam is considered first, deriving an analytical formula predicting the source-to-focus shift. Then the realistic case of a mirror affected by surface shape defects is examined, by taking into account metrological data and numerically solving the Huygens – Fresnel integral. The analytical and numerical solutions in the ideal and real cases are compared. Finally, it is sh...
Source: Journal of Synchrotron Radiation - August 19, 2019 Category: Physics Authors: Manfredda, M. Raimondi, L. Mahne, N. Zangrando, M. Tags: X-ray optics FEL free-electron lasers wavefront sensing Gaussian beams elliptical mirrors research papers Source Type: research

Operation of photon diagnostic imagers for beam commissioning at the European XFEL
X-ray photon beam diagnostic imagers are located at 24 positions in the European XFEL beam transport system to characterize the X-ray beam properties, and to give feedback for tuning and optimization of the electron acceleration and orbit, the undulators, and the X-ray optics. One year of commissioning allowed experience to be gained with these imagers, which will be reported here. The sensitive Spontaneous Radiation imager is useful for various investigations in spontaneous radiation mode: for undulator adjustments and for low-signal imaging applications. The   high-resolution Free-Electron Laser imager, 10   &micr...
Source: Journal of Synchrotron Radiation - August 18, 2019 Category: Physics Authors: Koch, A. Risch, J. Freund, W. Maltezopoulos, T. Planas, M. Gr ü nert, J. Tags: X-ray imaging beam diagnostics X-ray free-electron lasers beam transport systems scintillators research papers Source Type: research

Jitter correction for transmission X-ray microscopy via measurement of geometric moments
Transmission X-ray microscopes (TXMs) have become one of the most powerful tools for imaging 3D structures of nano-scale samples using the computed tomography (CT) principle. As a major error source, sample jitter caused by mechanical instability of the rotation stage produces shifted 2D projections, from which reconstructed images contain severe motion artifacts. In this paper, a jitter correction algorithm is proposed, that has high accuracy and computational efficiency for TXM experiments with or without nano-particle markers. Geometric moments (GMs) are measured on segmented projections for each angle and fitted to sin...
Source: Journal of Synchrotron Radiation - August 18, 2019 Category: Physics Authors: Wang, S. Liu, J. Li, Y. Chen, J. Guan, Y. Zhu, L. Tags: TXM jitter correction geometric moment motion artifact alignment research papers Source Type: research

Synchrotron in situ studies of mechanical activation treatment and γ -radiation impact on structural-phase transitions and high-temperature synthesis parameters during the formation of γ -(TiAl) compound
In situ synchrotron studies of structure and phase formation dynamics in mechanically activated (t = 7   min, power density 40   g) and mechanically activated with subsequent irradiation by γ -quanta 60Co powder mixture (Ti   64   wt% + Al) during high-temperature synthesis by the method of thermal explosion using induction heating are described. In situ high-temperature synthesis was carried out on the created experimental complex adapted for synchrotron X-ray diffraction methods. The sequence of formation and time – temperature interval of the metastable and main phases were determined. The impact ...
Source: Journal of Synchrotron Radiation - August 18, 2019 Category: Physics Authors: Loginova, M. Sobachkin, A. Sitnikov, A. Yakovlev, V. Filimonov, V. Myasnikov, A. Sharafutdinov, M. Tolochko, B. Gradoboev, A. Tags: mechanoactivation processing γ -irradiation powder materials titanium aluminides high-temperature synthesis experimental complex thermal explosion induction heating phase formation structure formation research papers Source Type: research

Reducing sample consumption for serial crystallography using acoustic drop ejection
Efficient sample delivery is an essential aspect of serial crystallography at both synchrotrons and X-ray free-electron lasers. Rastering fixed target chips through the X-ray beam is an efficient method for serial delivery from the perspectives of both sample consumption and beam time usage. Here, an approach for loading fixed targets using acoustic drop ejection is presented that does not compromise crystal quality, can reduce sample consumption by more than an order of magnitude and allows serial diffraction to be collected from a larger proportion of the crystals in the slurry. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - August 15, 2019 Category: Physics Authors: Davy, B. Axford, D. Beale, J. H. Butryn, A. Docker, P. Ebrahim, A. Leen, G. Orville, A.M. Owen, R.L. Aller, P. Tags: serial crystallography sample delivery fixed targets acoustic dispensing short communications Source Type: research

Soft X-ray varied-line-spacing gratings fabricated by   near-field holography using an electron beam lithography-written phase mask
A fabrication method comprising near-field holography (NFH) with an electron beam lithography (EBL)-written phase mask was developed to fabricate soft X-ray varied-line-spacing gratings (VLSGs). An EBL-written phase mask with an area of 52   mm × 30   mm and a central line density greater than 3000 lines   mm − 1 was used. The introduction of the EBL-written phase mask substantially simplified the NFH optics for pattern transfer. The characterization of the groove density distribution and diffraction efficiency of the fabricated VLSGs indicates that the EBL – NFH method is feasible and promising for...
Source: Journal of Synchrotron Radiation - August 15, 2019 Category: Physics Authors: Lin, D. Liu, Z. Dietrich, K. Sokolov, A. Sertsu, M.G. Zhou, H. Huo, T. Kroker, S. Chen, H. Qiu, K. Xu, X. Sch ä fers, F. Liu, Y. Kley, E.-B. Hong, Y. Tags: near-field holography electron beam lithography fabrication soft X-ray varied-line-spacing grating spectrometer research papers Source Type: research

Idea of thin-film beam splitters for two-colour beamlines
The idea to split soft X-ray and hard X-ray beams on the same axis into different directions is presented. A thin-film beam splitter can serve this purpose. Performances of thin-film beam splitters made of carbon and aluminium were examined. The idea of thin-film beam splitters expands possibilities in the design of two-colour beamlines. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - August 15, 2019 Category: Physics Authors: Abe, H. Tags: beam splitter soft and hard X-rays two-colour beamline research papers Source Type: research

Gamma-irradiation-induced micro-structural variations in flame-retardant polyurethane foam using synchrotron X-ray micro-tomography
In this study, in-house-developed flame-retardant rigid polyurethane foam samples were exposed to gamma irradiation doses in the 0 – 20   kGy range and synchrotron radiation X-ray micro-computed tomography (SR- µ CT) imaging was employed for the analysis of radiation-induced morphological variations in their cellular microstructure. Qualitative and quantitative analysis of SR- µ CT images has revealed significant variations in the average cell size, shape, wall thickness, orientations and spatial anisotropy of the cellular microstructure in polyurethane foam. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - August 15, 2019 Category: Physics Authors: Agrawal, A.K. Singh, B. Kashyap, Y.S. Shukla, M. Manjunath, B.S. Gadkari, S.C. Tags: X-ray imaging micro-tomography synchrotron imaging polyurethane foam gamma irradiation morphological image analysis cellular microstructure – property relation synchrotron X-ray micro-tomography research papers Source Type: research

Sample delivery using viscous media, a syringe and   a   syringe pump for serial crystallography
Sample delivery using injectors is widely used in serial crystallography (SX) and has significantly contributed to the determination of crystal structures at room temperature. However, sophisticated injector nozzle fabrication methods and sample delivery operations have made it difficult for ordinary users to access the SX research. Herein, a simple and easily accessible sample delivery method for SX experiments is introduced, that uses a viscous medium, commercially available syringe and syringe pump. The syringe containing the lysozyme crystals embedded in lipidic cubic phase (LCP) or polyacrylamide (PAM) delivery media ...
Source: Journal of Synchrotron Radiation - August 14, 2019 Category: Physics Authors: Park, S.-Y. Nam, K.H. Tags: serial crystallography sample delivery syringe pumps viscous media lipidic cubic phase polyacrylamide short communications Source Type: research

Effect of the third undulator field harmonic on spontaneous and stimulated undulator radiation
The effect of undulator field harmonics on spontaneous and stimulated undulator radiation, both on and off the undulator axis, is studied. Bessel factors for the undulators with field harmonics have been analytically calculated and numerically verified. The influence of the third undulator field harmonic on single-pass free-electron laser radiation is explored. Harmonic generation at the LCLS and SPring-8 free-electron lasers is modeled and analyzed. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - August 14, 2019 Category: Physics Authors: Zhukovsky, K.V. Tags: undulator radiation harmonics free-electron laser research papers Source Type: research

Simultaneous scanning near-field optical and X-ray diffraction microscopy for correlative nanoscale structure – property characterization
A multimodal imaging instrument has been developed that integrates scanning near-field optical microscopy with nanofocused synchrotron X-ray diffraction imaging. The instrument allows for the simultaneous nanoscale characterization of electronic/near-field optical properties of materials together with their crystallographic structure, facilitating the investigation of local structure – property relationships. The design, implementation and operating procedures of this instrument are reported. The scientific capabilities are demonstrated in a proof-of-principle study of the insulator – metal phase transition in ...
Source: Journal of Synchrotron Radiation - August 14, 2019 Category: Physics Authors: Li, Q. Marks, S.D. Bean, S. Fisher, M. Walko, D.A. DiChiara, A.D. Chen, X. Imura, K. Sato, N.K. Liu, M. Evans, P.G. Wen, H. Tags: multimodal imaging X-ray diffraction imaging scanning near-field optical microscopy structure – property correlations insulator metal transitions samarium sulfide scanning probe microscopy research papers Source Type: research

Resonant inelastic X-ray scattering of magnetic excitations under pressure
Resonant inelastic X-ray scattering (RIXS) is an extremely valuable tool for the study of elementary, including magnetic, excitations in matter. The latest developments of this technique have mostly been aimed at improving the energy resolution and performing polarization analysis of the scattered radiation, with a great impact on the interpretation and applicability of RIXS. Instead, this article focuses on the sample environment and presents a setup for high-pressure low-temperature RIXS measurements of low-energy excitations. The feasibility of these experiments is proved by probing the magnetic excitations of the bilay...
Source: Journal of Synchrotron Radiation - August 14, 2019 Category: Physics Authors: Rossi, M. Henriquet, C. Jacobs, J. Donnerer, C. Boseggia, S. Al-Zein, A. Fumagalli, R. Yao, Y. Vale, J.G. Hunter, E.C. Perry, R.S. Kantor, I. Garbarino, G. Crichton, W. Monaco, G. McMorrow, D.F. Krisch, M. Moretti   Sala, M. Tags: resonant inelastic X-ray scattering high pressure magnetic excitations correlated electron systems iridates research papers Source Type: research