Multifarious injection chamber for molecular structure study (MICOSS) system: development and application for serial femtosecond crystallography at Pohang Accelerator Laboratory X-ray Free-Electron Laser
The multifarious injection chamber for molecular structure study (MICOSS) experimental system has been developed at the Pohang Accelerator Laboratory X-ray Free-Electron Laser for conducting serial femtosecond crystallography. This system comprises several instruments such as a dedicated sample chamber, sample injectors, sample environment diagnostic system and detector stage for convenient distance manipulation. Serial femtosecond crystallography experiments of lysozyme crystals have been conducted successfully. The diffraction peaks have reached to ∼ 1.8   Å resolution at the photon energy of 9.785   keV. (...
Source: Journal of Synchrotron Radiation - February 19, 2018 Category: Physics Authors: Park, J. Kim, S. Kim, S. Nam, K.H. Tags: serial femtosecond crystallography PAL-XFEL lysozyme NCI sample injector MICOSS research papers Source Type: research

X-ray reflectivity from curved liquid interfaces
X-ray reflectivity studies of the structure of liquid – vapour and liquid – liquid interfaces at modern sources, such as free-electron lasers, are currently impeded by the lack of dedicated liquid surface diffractometers. It is shown that this obstacle can be overcome by an alternative experimental approach that uses the natural curvature of a liquid drop for variation of the angle of incidence. Two modes of operation are shown: (i) sequential reflectivity measurements by a nanometre beam and (ii) parallel acquisition of large ranges of a reflectivity curve by micrometre beams. The feasibility of the two method...
Source: Journal of Synchrotron Radiation - February 16, 2018 Category: Physics Authors: Festersen, S. Hrkac, S.B. Koops, C.T. Runge, B. Dane, T. Murphy, B.M. Magnussen, O.M. Tags: X-ray reflectivity liquid interfaces methods free-elecron laser synchrotron research papers Source Type: research

Small-angle scattering of polychromatic X-rays: effects of bandwidth, spectral shape and high harmonics
Polychromatic X-ray sources can be useful for photon-starved small-angle X-ray scattering given their high spectral fluxes. Their bandwidths, however, are 10 – 100 times larger than those using monochromators. To explore the feasibility, ideal scattering curves of homogeneous spherical particles for polychromatic X-rays are calculated and analyzed using the Guinier approach, maximum entropy and regularization methods. Monodisperse and polydisperse systems are explored. The influence of bandwidth and asymmetric spectra shape are explored via Gaussian and half-Gaussian spectra. Synchrotron undulator spectra represented...
Source: Journal of Synchrotron Radiation - February 16, 2018 Category: Physics Authors: Chen, S. Luo, S.-N. Tags: SAXS polychromatic size distribution undulator light source research papers Source Type: research

Energy-dependent dead-time correction in digital pulse processors applied to silicon drift detector's X-ray spectra
Dead-time effects in X-ray spectra taken with a digital pulse processor and a silicon drift detector were investigated when the number of events at the low-energy end of the spectrum was more than half of the total, at counting rates up to 56   kHz. It was found that dead-time losses in the spectra are energy dependent and an analytical correction for this effect, which takes into account pulse pile-up, is proposed. This and the usual models have been applied to experimental measurements, evaluating the dead-time fraction either from the calculations or using the value given by the detector acquisition system. The energy...
Source: Journal of Synchrotron Radiation - February 15, 2018 Category: Physics Authors: Barros, S.F. Vanin, V.R, Malafronte, A.A. Maidana, N.L. Martins, M.N. Tags: dead-time correction Si drift detector pile up research papers Source Type: research

Transmission of an X-ray beam through a two-dimensional photonic crystal and the Talbot effect
Results of computer simulations of the transmission of an X-ray beam through a two-dimensional photonic crystal as well as the propagation of an X-ray beam in free space behind the photonic crystal are reported. The photonic crystal consists of a square lattice of silicon cylinders of diameter 0.5   µ m. The amount of matter in the path of the X-ray beam rapidly decreases at the sides of the cylinder projections. Therefore the transmission is localized near the boundaries, and appears like a channeling effect. The iterative method of computer simulations is applied. This method is similar to the multi-slice method ...
Source: Journal of Synchrotron Radiation - February 15, 2018 Category: Physics Authors: Kohn, V.G. Tags: X-ray transmission two-dimensional photonic crystal Talbot effect computer simulations iterative algorithm research papers Source Type: research

High-energy-resolution diced spherical quartz analyzers for resonant inelastic X-ray scattering
A novel diced spherical quartz analyzer for use in resonant inelastic X-ray scattering (RIXS) is introduced, achieving an unprecedented energy resolution of 10.53   meV at the Ir L3 absorption edge (11.215   keV). In this work the fabrication process and the characterization of the analyzer are presented, and an example of a RIXS spectrum of magnetic excitations in a Sr3Ir2O7 sample is   shown. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 15, 2018 Category: Physics Authors: Said, A.H. Gog, T. Wieczorek, M. Huang, X. Casa, D. Kasman, E. Divan, R. Kim, J.H. Tags: RIXS high resolution analyzer inelastic X-ray quartz research papers Source Type: research

Nuclear resonance reflectivity from a [57Fe/Cr]30 multilayer with the Synchrotron M ö ssbauer Source
M ö ssbauer reflectivity spectra and nuclear resonance reflectivity (NRR) curves have been measured using the Synchrotron M ö ssbauer Source (SMS) for a [57Fe/Cr]30 periodic multilayer, characterized by the antiferromagnetic interlayer coupling between adjacent 57Fe layers. Specific features of the M ö ssbauer reflectivity spectra measured with π -polarized radiation of the SMS near the critical angle and at the `magnetic' maximum on the NRR curve are analyzed. The variation of the ratio of lines in the M ö ssbauer reflectivity spectra and the change of the intensity of the `magnetic' maximum under a...
Source: Journal of Synchrotron Radiation - February 15, 2018 Category: Physics Authors: Andreeva, M.A. Baulin, R.A. Chumakov, A.I. R ü ffer, R. Smirnov, G.V. Babanov, Y.A. Devyaterikov, D.I. Milyaev, M.A. Ponomarev, D.A. Romashev, L.N. Ustinov, V.V. Tags: magnetic multilayers antiferromagnetic interlayer coupling ö ssbauer spectroscopy nuclear resonance reflectivity Synchrotron M ssbauer Source research papers Source Type: research

FemtoMAX – an X-ray beamline for structural dynamics at the short-pulse facility of MAX IV
The FemtoMAX beamline facilitates studies of the structural dynamics of materials. Such studies are of fundamental importance for key scientific problems related to programming materials using light, enabling new storage media and new manufacturing techniques, obtaining sustainable energy by mimicking photosynthesis, and gleaning insights into chemical and biological functional dynamics. The FemtoMAX beamline utilizes the MAX IV linear accelerator as an electron source. The photon bursts have a pulse length of 100   fs, which is on the timescale of molecular vibrations, and have wavelengths matching interatomic distances...
Source: Journal of Synchrotron Radiation - February 14, 2018 Category: Physics Authors: Enquist, H. Jurgilaitis, A. Jarnac, A. Bengtsson, Å .U.J. Burza, M. Curbis, F. Disch, C. Ekstr ö m, J.C. Harb, M. Isaksson, L. Kotur, M. Kroon, D. Lindau, F. Mansten, E. Nygaard, J. Persson, A.I.H. Pham, V.T. Rissi, M. Thorin, S. Tu, C.-M. Wall é n, E. Tags: structural dynamics pump – probe laser beamline ultrafast beamlines Source Type: research

Microbubbles containing gadolinium as contrast agents for both phase contrast and magnetic resonance imaging
In this study, the feasibility of using microbubbles containing gadolinium (MCG) as contrast agents for both phase contrast imaging (PCI) and magnetic resonance imaging (MRI) are investigated. MCG were made by encapsulating sulfur hexafluoride (SF6) gas with gadolinium and lyophilized powder. Absorption contrast imaging (ACI) and PCI of MCG were performed and compared in vitro. MCG were injected into the main portal trunk of living rats. PCI and MRI were performed at 2   min and 10   min after MCG injection, respectively. PCI exploited the differences in the refractive index and visibly showed the MCG, which were not d...
Source: Journal of Synchrotron Radiation - February 14, 2018 Category: Physics Authors: Tang, R. Yan, F. Yang, G.-Y. Chen, K.-M. Tags: phase contrast imaging microbubble gadolinium research papers Source Type: research

Quantum regime of a plasma-wave-pumped free-electron laser in the presence of an axial magnetic field
The quantum regime of a plasma-whistler-wave-pumped free-electron laser (FEL) in the presence of an axial-guide magnetic field is presented. By quantizing both the plasma whistler field and axial magnetic field, an N-particle three-dimensional Hamiltonian of quantum-FEL (QFEL) has been derived. Employing Heisenberg evolution equations and introducing a new collective operator which controls the vertical motion of electrons, a quantum dispersion relation of the plasma whistler wiggler has been obtained analytically. Numerical results indicate that, by increasing the intrinsic quantum momentum spread and/or increasing the ax...
Source: Journal of Synchrotron Radiation - February 14, 2018 Category: Physics Authors: Shirvani, H. Jafari, S. Tags: quantum-FEL plasma whistler wave Heisenberg evolution equations axial magnetic field strength research papers Source Type: research

Efficiency and coherence preservation studies of Be refractive lenses for XFELO application
Performance tests of parabolic beryllium refractive lenses, considered as X-ray focusing elements in the future X-ray free-electron laser oscillator (XFELO), are reported. Single and double refractive lenses were subject to X-ray tests, which included: surface profile, transmissivity measurements, imaging capabilities and wavefront distortion with grating interferometry. Optical metrology revealed that surface profiles were close to the design specification in terms of the figure and roughness. The transmissivity of the lenses is>94% at 8   keV and>98% at 14.4   and 18   keV. These values are close to the theor...
Source: Journal of Synchrotron Radiation - February 14, 2018 Category: Physics Authors: Kolodziej, T. Stoupin, S. Grizolli, W. Krzywinski, J. Shi, X. Kim, K.-J. Qian, J. Assoufid, L. Shvyd'ko, Yu. Tags: X-rays X-ray focusing X-ray optics refractive lenses research papers Source Type: research

Synchrotron Radiation and Free-Electron Lasers. Principles of Coherent X-ray Generation. By Kwang-Je Kim, Artur Braun and Zhirong Huang. Cambridge University Press, 2017. Pp. 298. Price GBP 89.99, hardback, ISBN 978-1107162617.
(Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 13, 2018 Category: Physics Authors: Helliwell, J.R. Tags: book review synchrotron radiation FEL radiation book reviews Source Type: research

Multi-channel in situ dynamic light scattering instrumentation enhancing biological small-angle X-ray scattering experiments at the PETRA III beamline P12
This study also shows and confirms that the newly designed sample compartment with attached DLS instrumentation does not disturb SAXS measurements. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 13, 2018 Category: Physics Authors: Falke, S. Dierks, K. Blanchet, C. Graewert, M. Cipriani, F. Meijers, R. Svergun, D. Betzel, C. Tags: in situ DLS multi-channel radius determination BioSAXS sample compartment sample quality assessment research papers Source Type: research

Anisotropy enhanced X-ray scattering from solvated transition metal complexes
Time-resolved X-ray scattering patterns from photoexcited molecules in solution are in many cases anisotropic at the ultrafast time scales accessible at X-ray free-electron lasers (XFELs). This anisotropy arises from the interaction of a linearly polarized UV – Vis pump laser pulse with the sample, which induces anisotropic structural changes that can be captured by femtosecond X-ray pulses. In this work, a method for quantitative analysis of the anisotropic scattering signal arising from an ensemble of molecules is described, and it is demonstrated how its use can enhance the structural sensitivity of the time-resol...
Source: Journal of Synchrotron Radiation - February 13, 2018 Category: Physics Authors: Biasin, E. van Driel, T.B. Levi, G. Laursen, M.G. Dohn, A.O. Moltke, A. Vester, P. Hansen, F.B.K. Kjaer, K.S. Harlang, T. Hartsock, R. Christensen, M. Gaffney, K.J. Henriksen, N.E. M ø ller, K.B. Haldrup, K. Nielsen, M.M. Tags: time-resolved anisotropic scattering orientational selection XFEL ultrafast molecular structure research papers Source Type: research

Enhancement of measurement accuracy of X-ray PIV in comparison with the micro-PIV technique
In this study, a new two-dimensional velocity field extraction technique is proposed to overcome technological limitations. To resolve the problem of finding a correction coefficient, the velocity field information obtained by X-ray PIV and micro-PIV techniques for disturbed flow in a concentric stenosis with 50% severity was quantitatively compared. Micro-PIV experiments were conducted for single-plane and summation images, which provide similar positional information of particles as X-ray images. The correction coefficient was obtained by establishing the relationship between velocity data obtained from summation images ...
Source: Journal of Synchrotron Radiation - February 13, 2018 Category: Physics Authors: Park, H. Jung, S.Y. Park, J.H. Kim, J.H. Lee, S.J. Tags: X-ray PIV micro-PIV stenosis biofluid flow correction coefficient research papers Source Type: research

Software for the data analysis of the arrival-timing monitor at SACLA
X-ray free-electron laser (XFEL) pulses from SPring-8 Å ngstrom Compact free-electron LAser (SACLA) with a temporal duration of (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 7, 2018 Category: Physics Authors: Nakajima, K. Joti, Y. Katayama, T. Owada, S. Togashi, T. Abe, T. Kameshima, T. Okada, K. Sugimoto, T. Yamaga, M. Hatsui, T. Yabashi, M. Tags: X-ray free-electron laser arrival-timing monitor data analysis software SACLA computer programs Source Type: research

X-ray position-sensitive duo-lateral diamond detectors at SOLEIL
The performance of a diamond X-ray beam position monitor is reported. This detector consists of an ionization solid-state chamber based on a thin single-crystal chemical-vapour-deposition diamond with position-sensitive resistive electrodes in a duo-lateral configuration. The detector's linearity, homogeneity and responsivity were studied on beamlines at Synchrotron SOLEIL with various beam sizes, intensities and energies. These measurements demonstrate the large and homogeneous (absorption variation of less than 0.7% over 500   µ m × 500   µ m) active area of the detector, with linear responses indep...
Source: Journal of Synchrotron Radiation - February 7, 2018 Category: Physics Authors: Desjardins, K. Bordessoule, M. Pomorski, M. Tags: X-ray beam position monitor XBPM PSD diamond detector noise analysis research papers Source Type: research

GAPD: a GPU-accelerated atom-based polychromatic diffraction simulation code
GAPD, a graphics-processing-unit (GPU)-accelerated atom-based polychromatic diffraction simulation code for direct, kinematics-based, simulations of X-ray/electron diffraction of large-scale atomic systems with mono-/polychromatic beams and arbitrary plane detector geometries, is presented. This code implements GPU parallel computation via both real- and reciprocal-space decompositions. With GAPD, direct simulations are performed of the reciprocal lattice node of ultralarge systems ( ∼ 5 billion atoms) and diffraction patterns of single-crystal and polycrystalline configurations with mono- and polychromatic X-ray beams...
Source: Journal of Synchrotron Radiation - February 6, 2018 Category: Physics Authors: E, J. C. Wang, L. Chen, S. Zhang, Y. Y. Luo, S. N. Tags: diffraction simulation reciprocal space mapping polychromatic beam parallel computing computer programs Source Type: research

M Ö NCH detector enables fast and low-dose free-propagation phase-contrast computed tomography of in situ mouse lungs
Due to the complexity of the underlying pathomechanism, in vivo mouse lung-disease models continue to be of great importance in preclinical respiratory research. Longitudinal studies following the cause of a disease or evaluating treatment efficacy are of particular interest but challenging due to the small size of the mouse lung and the fast breathing rate. Synchrotron-based in-line phase-contrast computed tomography imaging has been successfully applied in lung research in various applications, but mostly at dose levels that forbid longitudinal in vivo studies. Here, the novel charge-integrating hybrid detector M Ö ...
Source: Journal of Synchrotron Radiation - February 6, 2018 Category: Physics Authors: Dullin, C. Albers, J. Tromba, G. Andr ä , M. Ramilli, M. Bergamaschi, A. Tags: mouse-lung imaging low dose phase-contrast computed tomography charge-integration detector short communications Source Type: research

An electrochemical cell with sapphire windows for operando synchrotron X-ray powder diffraction and spectroscopy studies of high-power and high-voltage electrodes for metal-ion batteries
A new multi-purpose operando electrochemical cell was designed, constructed and tested on the Swiss – Norwegian Beamlines BM01 and BM31 at the European Synchrotron Radiation Facility. Single-crystal sapphire X-ray windows provide a good signal-to-noise ratio, excellent electrochemical contact because of the constant pressure between the electrodes, and perfect electrochemical stability at high potentials due to the inert and non-conductive nature of sapphire. Examination of the phase transformations in the Li1 – xFe0.5Mn0.5PO4 positive electrode (cathode) material at C/2 and 10C charge and discharge rates, and ...
Source: Journal of Synchrotron Radiation - February 6, 2018 Category: Physics Authors: Drozhzhin, O.A. Tereshchenko, I.V. Emerich, H. Antipov, E.V. Abakumov, A.M. Chernyshov, D. Tags: operando electrochemical cells metal-ion batteries X-ray diffraction X-ray absorption research papers Source Type: research

Polarization-independent absorption enhancement in a graphene square array with a cascaded grating structure
The polarization-independent enhanced absorption effect of graphene in the near-infrared range is investigated. This is achieved by placing a graphene square array on top of a dielectric square array backed by a two-dimensional multilayer grating. Total optical absorption in graphene can be attributed to critical coupling, which is achieved through the combined effect of guided-mode resonance with the dielectric square array and the photonic band gap with the two-dimensional multilayer grating. To reveal the physical origin of such a phenomenon, the electromagnetic field distributions for both polarizations are illustrated...
Source: Journal of Synchrotron Radiation - February 6, 2018 Category: Physics Authors: Wu, J. Tags: diffraction and gratings metamaterials graphene spectrum-selective absorption research papers Source Type: research

Experimental study of EUV mirror radiation damage resistance under long-term free-electron laser exposures below the single-shot damage threshold
The durability of grazing- and normal-incidence optical coatings has been experimentally assessed under free-electron laser irradiation at various numbers of pulses up to 16 million shots and various fluence levels below 10% of the single-shot damage threshold. The experiment was performed at FLASH, the Free-electron LASer in Hamburg, using 13.5   nm extreme UV (EUV) radiation with 100   fs pulse duration. Polycrystalline ruthenium and amorphous carbon 50   nm thin films on silicon substrates were tested at total external reflection angles of 20 ° and 10 ° grazing incidence, respectively. Mo/Si periodical mul...
Source: Journal of Synchrotron Radiation - December 21, 2017 Category: Physics Authors: Makhotkin, I.A. Sobierajski, R. Chalupsk ý , J. Tiedtke, K. de Vries, G. St ö rmer, M. Scholze, F. Siewert, F. van de Kruijs, R.W.E. Milov, I. Louis, E. Jacyna, I. Jurek, M. Klinger, D. Nittler, L. Syryanyy, Y. Juha, L. H á jkov á , V. Vozda, V. Buria Tags: free-electron laser induced damage EUV optics thin films FELs research papers Source Type: research

PhotonDiag2017 workshop: introductory overview
This issue of the Journal of Synchrotron Radiation is a special issue including papers from the PhotonDiag2017 workshop. Here, a brief introduction is given. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - December 21, 2017 Category: Physics Authors: Cocco, D. Moeller, S. Ploenjes, E. Zangrando, M. Tags: free-electron laser (FEL) PhotonDiag2017 workshop photon diagnostics beamline instrumentation beamline design editorial Source Type: research

An IAEA multi-technique X-ray spectrometry endstation at Elettra Sincrotrone Trieste: benchmarking results and interdisciplinary applications
The International Atomic Energy Agency (IAEA) jointly with the Elettra Sincrotrone Trieste (EST) operates a multipurpose X-ray spectrometry endstation at the X-ray Fluorescence beamline (10.1L). The facility has been available to external users since the beginning of 2015 through the peer-review process of EST. Using this collaboration framework, the IAEA supports and promotes synchrotron-radiation-based research and training activities for various research groups from the IAEA Member States, especially those who have limited previous experience and resources to access a synchrotron radiation facility. This paper aims to p...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Karydas, A.G. Czyzycki, M. Leani, J.J. Migliori, A. Osan, J. Bogovac, M. Wrobel, P. Vakula, N. Padilla-Alvarez, R. Menk, R.H. Gol, M.G. Antonelli, M. Tiwari, M.K. Caliri, C. Vogel-Miku š , K. Darby, I. Kaiser, R.B. Tags: X-ray fluorescence grazing incidence X-ray reflectometry X-ray absorption spectroscopy beamline endstation research papers Source Type: research

Separation of superimposed images with subpixel shift
The problem of the separation of superimposed images is considered in the particular case of a steady background and a foreground that is composed of different patterns separated in space, each with a compact support. Each pattern of the foreground may move in time independently. A single pair of these superimposed images is assumed to be available, and the displacement amplitude is typically smaller than the pixel size. Further, assuming that the background is smoothly varying in space, an original algorithm is proposed. To illustrate the performance of the method, a real test case of X-ray tomographic radiographs with mo...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Jailin, C. Poncelet, M. Roux, S. Tags: superimposed images image mixture image separation spatial shift subpixel motion research papers Source Type: research

Direct experimental observation of the gas density depression effect using a two-bunch X-ray FEL beam
The experimental observation of the depression effect in gas devices designed for X-ray free-electron lasers (FELs) is reported. The measurements were carried out at the Linac Coherent Light Source using a two-bunch FEL beam at 6.5   keV with 122.5   ns separation passing through an argon gas cell. The relative intensities of the two pulses of the two-bunch beam were measured, after and before the gas cell, from X-ray scattering off thin targets by using fast diodes with sufficient temporal resolution. At a cell pressure of 140   hPa, it was found that the after-to-before ratio of the intensities of the second pulse ...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Feng, Y. Schafer, D.W. Song, S. Sun, Y. Zhu, D. Krzywinski, J. Robert, A. Wu, J. Decker, F.-J. Tags: gas density depression X-ray FEL attenuation pump – probe research papers Source Type: research

Gratings for synchrotron and FEL beamlines: a   project for the manufacture of ultra-precise gratings at Helmholtz Zentrum Berlin
Blazed gratings are of dedicated interest for the monochromatization of synchrotron radiation when a high photon flux is required, such as, for example, in resonant inelastic X-ray scattering experiments or when the use of laminar gratings is excluded due to too high flux densities and expected damage, for example at free-electron laser beamlines. Their availability became a bottleneck since the decommissioning of the grating manufacture facility at Carl Zeiss in Oberkochen. To resolve this situation a new technological laboratory was established at the Helmholtz Zentrum Berlin, including instrumentation from Carl Zeiss. B...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Siewert, F. L ö chel, B. Buchheim, J. Eggenstein, F. Firsov, A. Gwalt, G. Kutz, O. Lemke, S. Nelles, B. Rudolph, I. Sch ä fers, F. Seliger, T. Senf, F. Sokolov, A. Waberski, C. Wolf, J. Zeschke, T. Zizak, I. Follath, R. Arnold, T. Frost, F. Pietag, F. E Tags: gratings soft X-ray optics diffractive optics metrology research papers Source Type: research

Focusing X-ray free-electron laser pulses using Kirkpatrick – Baez mirrors at the NCI hutch of the   PAL-XFEL
The Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) is a recently commissioned X-ray free-electron laser (XFEL) facility that provides intense ultrashort X-ray pulses based on the self-amplified spontaneous emission process. The nano-crystallography and coherent imaging (NCI) hutch with forward-scattering geometry is located at the hard X-ray beamline of the PAL-XFEL and provides opportunities to perform serial femtosecond crystallography and coherent X-ray diffraction imaging. To produce intense high-density XFEL pulses at the interaction positions between the X-rays and various samples, a microfocusing...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Kim, J. Kim, H.-Y. Park, J. Kim, S. Kim, S. Rah, S. Lim, J. Nam, K.H. Tags: microfocusing X-ray optics KB mirror X-ray free-electron laser PAL-XFEL NCI beamlines Source Type: research

Effect of reflection and refraction on NEXAFS spectra measured in TEY mode
The evolution of near-edge X-ray absorption fine structure in the vicinity of the K-absorption edge of oxygen for HfO2 over a wide range of incidence angles is analyzed by simultaneous implementation of the total-electron-yield (TEY) method and X-ray reflection spectroscopy. It is established that the effect of refraction on the TEY spectrum is greater than that of reflection and extends into the angular region up to angles 2 θ c. Within angles that are less than the critical angle, both the reflection and refraction strongly distort the shape of the TEY spectrum. Limitations of the technique for the calculation of o...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Filatova, E. Sokolov, A. Tags: NEXAFS total electron yield method X-ray reflection spectroscopy research papers Source Type: research

Fast X-ray reflectivity measurements using an X-ray pixel area detector at the DiffAbs beamline, Synchrotron SOLEIL
This paper describes a method for rapid measurements of the specular X-ray reflectivity signal using an area detector and a monochromatic, well collimated X-ray beam (divergence below 0.01 ° ), combined with a continuous data acquisition mode during the angular movements of the sample and detector. In addition to the total integrated (and background-corrected) reflectivity signal, this approach yields a three-dimensional mapping of the reciprocal space in the vicinity of its origin. Grazing-incidence small-angle scattering signals are recorded simultaneously. Measurements up to high momentum transfer values (close to 0...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Mocuta, C. Stanescu, S. Gallard, M. Barbier, A. Dawiec, A. Kedjar, B. Leclercq, N. Thiaudiere, D. Tags: X-ray reflectivity hybrid pixel area detector research papers Source Type: research

Electron and photon diagnostics for plasma acceleration-based FELs
It is now well established that laser plasma acceleration (LPA) is an innovative and good candidate in the beam acceleration field. Relativistic beams are indeed produced up to several GeV but their quality remains to be demonstrated in the highly demanding case of free-electron lasers (FELs). Several experiments have already shown the feasibility of synchrotron radiation delivery based on LPA but free-electron lasing has still to be achieved. Since the quality of the LPA beam inside the undulator is the critical issue, any LPA-based FEL experiment requires a refined characterization of the beam properties along the transp...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Labat, M. El Ajjouri, M. Hubert, N. Andre, T. Loulergue, A. Couprie, M.-E. Tags: diagnostics free-electron laser laser plasma accelerator research papers Source Type: research

Damage thresholds for blaze diffraction gratings and grazing incidence optics at an X-ray free-electron laser
The Linac Coherent Light Source is upgrading its machine to high repetition rate and to extended ranges. Novel coatings, with limited surface oxidation, which are able to work at the carbon edge, are required. In addition, high-resolution soft X-ray monochromators become necessary. One of the big challenges is to design the mirror geometry and the grating profile to have high reflectivity (or efficiency) and at the same time survive the high peak energy of the free-electron laser pulses. For these reasons the experimental damage threshold, at 900   eV, of two platinum-coated gratings with different blazed angles has been...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Krzywinski, J. Conley, R. Moeller, S. Gwalt, G. Siewert, F. Waberski, C. Zeschke, T. Cocco, D. Tags: free-electron laser optical damage diffraction gratings research papers Source Type: research

Timing methodologies and studies at the FERMI free-electron laser
Time-resolved investigations have begun a new era of chemistry and physics, enabling the monitoring in real time of the dynamics of chemical reactions and matter. Induced transient optical absorption is a basic ultrafast electronic effect, originated by a partial depletion of the valence band, that can be triggered by exposing insulators and semiconductors to sub-picosecond extreme-ultraviolet pulses. Besides its scientific and fundamental implications, this process is very important as it is routinely applied in free-electron laser (FEL) facilities to achieve the temporal superposition between FEL and optical laser pulses...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Mincigrucci, R. Bencivenga, F. Principi, E. Capotondi, F. Foglia, L. Naumenko, D. Simoncig, A. Dal Zilio, S. Gessini, A. Kurdi, G. Mahne, N. Manfredda, M. Matruglio, A. Nikolov, I. Pedersoli, E. Raimondi, L. Sergo, R. Zangrando, M. Masciovecchio, C. Tags: cross correlation timing FEL diagnostics pump – probe research papers Source Type: research

Single-shot arrival timing diagnostics for a soft X-ray free-electron laser beamline at SACLA
Arrival timing diagnostics performed at a soft X-ray free-electron laser (FEL) beamline of SACLA are described. Intense soft X-ray FEL pulses with one-dimensional focusing efficiently induce transient changes of optical reflectivity on the surface of GaAs. The arrival timing between soft X-ray FEL and optical laser pulses was successfully measured as a spatial position of the reflectivity change. The temporal resolution evaluated from the imaging system reaches ∼ 10   fs. This method requires only a small portion of the incident pulse energy, which enables the simultaneous operation of the arrival timing diagnostics ...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Owada, S. Nakajima, K. Togashi, T. Kayatama, T. Yabashi, M. Tags: X-ray free-electron laser soft X-rays arrival timing diagnostics research papers Source Type: research

Characterization of ultrafast free-electron laser pulses using extreme-ultraviolet transient gratings
The characterization of the time structure of ultrafast photon pulses in the extreme-ultraviolet (EUV) and soft X-ray spectral ranges is of high relevance for a number of scientific applications and photon diagnostics. Such measurements can be performed following different strategies and often require large setups and rather high pulse energies. Here, high-quality measurements carried out by exploiting the transient grating process, i.e. a third-order non-linear process sensitive to the time-overlap between two crossed EUV pulses, is reported. From such measurements it is possible to obtain information on both the second-o...
Source: Journal of Synchrotron Radiation - December 19, 2017 Category: Physics Authors: Capotondi, F. Foglia, L. Kiskinova, M. Masciovecchio, C. Mincigrucci, R. Naumenko, D. Pedersoli, E. Simoncig, A. Bencivenga, F. Tags: free-electron laser XUV pulse duration diagnostic transient grating spectroscopy research papers Source Type: research

Digital fast pulse shape and height analysis on cadmium – zinc – telluride arrays for high-flux energy-resolved X-ray imaging
Cadmium – zinc – telluride (CZT) arrays with photon-counting and energy-resolving capabilities are widely proposed for next-generation X-ray imaging systems. This work presents the performance of a 2   mm-thick CZT pixel detector, with pixel pitches of 500 and 250   µ m, dc coupled to a fast and low-noise ASIC (PIXIE ASIC), characterized only by the preamplifier stage. A custom 16-channel digital readout electronics was used, able to digitize and process continuously the signals from each output ASIC channel. The digital system performs on-line fast pulse shape and height analysis, with a low dead-tim...
Source: Journal of Synchrotron Radiation - December 14, 2017 Category: Physics Authors: Abbene, L. Principato, F. Gerardi, G. Bettelli, M. Seller, P. Veale, M.C. Zambelli, N. Benassi, G. Zappettini, A. Tags: digital pulse shape analysis X-ray and γ -ray detectors CdZnTe detectors high flux charge sharing energy-resolved photon counting detectors research papers Source Type: research

In situ electrochemical synchrotron radiation for Li-ion batteries
Observing the electronic structure, compositional change and morphological evolution of the surface and interface of a battery during operation provides essential information for developing new electrode materials for Li-ion batteries (LIBs); this is because such observations demonstrate the fundamental reactions occurring inside the electrode materials. Moreover, obtaining detailed data on chemical phase changes and distributions by analyzing an operating LIB is the most effective method for exploring the intercalation/de-intercalation process, kinetics and the relationship between phase change or phase distribution and b...
Source: Journal of Synchrotron Radiation - December 14, 2017 Category: Physics Authors: Alemu, T. Wang, F.-M. Tags: in situ synchrotron radiation Li-ion battery X-ray diffraction spectroscopy transmission X-ray microscopy X-ray absorption spectroscopy solid electrolyte interphase topical reviews Source Type: research

Double-grating monochromatic beamline with ultrafast response for FLASH2 at DESY
The preliminary design of a monochromatic beamline for FLASH2 at DESY is presented. The monochromator is tunable in the 50 – 1000   eV energy range with resolving power higher than 1000 and temporal response below 50   fs over the whole energy range. A time-delay-compensated configuration using the variable-line-spacing monochromator design with two gratings is adopted: the first grating disperses the radiation on its output plane, where the intermediate slit performs the spectral selection; the second grating compensates for the pulse-front tilt and for the spectral dispersion due to diffraction from the first g...
Source: Journal of Synchrotron Radiation - December 14, 2017 Category: Physics Authors: Poletto, L. Frassetto, F. Brenner, G. Kuhlmann, M. Pl ö njes, E. Tags: time-delay-compensated monochromator diffraction variable-line-spaced grating free-electron laser research papers Source Type: research

Grating configurations to compress free-electron laser pulses
The optical layout of soft X-ray grating compressors designed to provide both positive and negative group-delay dispersion (GDD) is discussed. They are tailored for chirped-pulse-amplification experiments with seeded free-electron laser sources. Designs with plane or concave gratings are discussed, depending on the sign of the GDD to be introduced. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - December 14, 2017 Category: Physics Authors: Poletto, L. Frassetto, F. Tags: ultrafast technology free-electron laser diffraction gratings chirped-pulse amplification research papers Source Type: research

A soft X-ray free-electron laser beamline at SACLA: the light source, photon beamline and experimental station
The design and performance of a soft X-ray free-electron laser (FEL) beamline of the SPring-8 Compact free-electron LAser (SACLA) are described. The SPring-8 Compact SASE Source test accelerator, a prototype machine of SACLA, was relocated to the SACLA undulator hall for dedicated use for the soft X-ray FEL beamline. Since the accelerator is operated independently of the SACLA main linac that drives the two hard X-ray beamlines, it is possible to produce both soft and hard X-ray FEL simultaneously. The FEL pulse energy reached 110   µ J at a wavelength of 12.4   nm (i.e. photon energy of 100   eV) with an elect...
Source: Journal of Synchrotron Radiation - December 13, 2017 Category: Physics Authors: Owada, S. Togawa, K. Inagaki, T. Hara, T. Tanaka, T. Joti, Y. Koyama, T. Nakajima, K. Ohashi, H. Senba, Y. Togashi, T. Tono, K. Yamaga, M. Yumoto, H. Yabashi, M. Tanaka, H. Ishikawa, T. Tags: free-electron laser soft X-ray beamline instrumentation beamlines Source Type: research

Fast projection/backprojection and incremental methods applied to synchrotron light tomographic reconstruction
Iterative methods for tomographic image reconstruction have the computational cost of each iteration dominated by the computation of the (back)projection operator, which take roughly O(N3) floating point operations (flops) for N × N pixels images. Furthermore, classical iterative algorithms may take too many iterations in order to achieve acceptable images, thereby making the use of these techniques unpractical for high-resolution images. Techniques have been developed in the literature in order to reduce the computational cost of the (back)projection operator to O(N2logN) flops. Also, incremental algorithms have bee...
Source: Journal of Synchrotron Radiation - December 13, 2017 Category: Physics Authors: Lima, C. Helou, E.S. Tags: tomographic reconstruction iterative methods statistical model fast computation of projection/backprojection research papers Source Type: research

X-ray natural circular dichroism in langasite crystal
Optical activity in the X-ray range stems from the electric-dipole – electric-quadrupole interference terms mixing multipoles of opposite parity, and can be observed exclusively in systems with broken inversion symmetry. The gyration tensor formalism is used to describe the X-ray optical activity in langasite La3Ga5SiO14 crystal with the P321 space group. An experimental study of the X-ray natural circular dichroism (XNCD) near the Ga K-edge in La3Ga5SiO14 single crystal was performed at ESRF beamline ID12, both along and perpendicular to the crystal optical axis. The combination of the quantum mechanical calculation...
Source: Journal of Synchrotron Radiation - December 13, 2017 Category: Physics Authors: Oreshko, A.P. Ovchinnikova, E.N. Rogalev, A. Wilhelm, F. Mill, B.V. Dmitrienko, V.E. Tags: optical activity circular dichroism X-ray absorption spectra research papers Source Type: research

THz pulse doubler at FLASH: double pulses for pump – probe experiments at X-ray FELs
FLASH, the X-ray free-electron laser in Hamburg, Germany, employs a narrowband high-field accelerator THz source for unique THz pump X-ray probe experiments. However, the large difference in optical paths of the THz and X-ray beamlines prevents utilization of the machine's full potential (e.g. extreme pulse energies in the soft X-ray range). To solve this issue, lasing of double electron bunches, separated by 28 periods of the driving radiofrequency (at 1.3   GHz), timed for the temporal overlap of THz and X-ray pulses at the experimental station has been employed. In order to optimize conditions for a typical THz pump X...
Source: Journal of Synchrotron Radiation - December 13, 2017 Category: Physics Authors: Zapolnova, E. Golz, T. Pan, R. Klose, K. Schreiber, S. Stojanovic, N. Tags: FLASH free-electron laser THz beamline pump – probe experiments double electron bunches X-rays research papers Source Type: research

X-ray Fourier transform holography by amplitude-division-type Fresnel zone plate interferometer
A two-block X-ray Fresnel zone plate system forms two-beams – a plane wave and a spherical wave – which interfere at the focal distance of the virtual source of the spherical wave. An object placed in the path of the plane wave forms an object wave and the spherical wave is the reference wave. The recorded intensity distribution is the Fourier transform hologram of the object. Analytical and numerical calculations show the possibilities of this scheme to record the hologram and reconstruct the object image. Examples of recording holograms of a one-dimensional cosine-like grating and a two-dimensional grid objec...
Source: Journal of Synchrotron Radiation - December 11, 2017 Category: Physics Authors: Balyan, M. Haroutunyan, L. Tags: Fresnel zone plate interferometer X-ray Fourier transform holography reconstruction research papers Source Type: research

Pulse-resolved intensity measurements at a hard X-ray FEL using semi-transparent diamond detectors
Solid-state ionization chambers are presented based on thin diamond crystals that allow pulse-resolved intensity measurements at a hard X-ray free-electron laser (FEL), up to the 4.5   MHz repetition rate that will become available at the European XFEL. Due to the small X-ray absorption of diamond the thin detectors are semi-transparent which eases their use as non-invasive monitoring devices in the beam. FELs are characterized by strong pulse-to-pulse intensity fluctuations due to the self-amplified spontaneous emission (SASE) process and in many experiments it is mandatory to monitor the intensity of each individual pu...
Source: Journal of Synchrotron Radiation - December 11, 2017 Category: Physics Authors: Roth, T. Freund, W. Boesenberg, U. Carini, G. Song, S. Lefeuvre, G. Goikhman, A. Fischer, M. Schreck, M. Gr ü nert, J. Madsen, A. Tags: XFEL diamond detector X-ray intensity measurement research papers Source Type: research

Transient thermal stress wave and vibrational analyses of a thin diamond crystal for X-ray free-electron lasers under high-repetition-rate operation
High-brightness X-ray free-electron lasers (FELs) are perceived as fourth-generation light sources providing unprecedented capabilities for frontier scientific researches in many fields. Thin crystals are important to generate coherent seeds in the self-seeding configuration, provide precise spectral measurements, and split X-ray FEL pulses, etc. In all of these applications a high-intensity X-ray FEL pulse impinges on the thin crystal and deposits a certain amount of heat load, potentially impairing the performance. In the present paper, transient thermal stress wave and vibrational analyses as well as transient thermal a...
Source: Journal of Synchrotron Radiation - December 11, 2017 Category: Physics Authors: Yang, B. Wang, S. Wu, J. Tags: diamond free electron laser stress waves thermal shock thin crystal monochromator thin crystal spectroscopy vibration X-ray research papers Source Type: research

Laser power meters as an X-ray power diagnostic for LCLS-II
For the LCLS-II X-ray instruments, laser power meters are being developed as compact X-ray power diagnostics to operate at soft and tender X-ray photon energies. These diagnostics can be installed at various locations along an X-ray free-electron laser (FEL) beamline in order to monitor the transmission of X-ray optics along the beam path. In addition, the power meters will be used to determine the absolute X-ray power at the endstations. Here, thermopile power meters, which measure average power, and have been chosen primarily for their compatibility with the high repetition rates at LCLS-II, are evaluated. A number of ch...
Source: Journal of Synchrotron Radiation - December 11, 2017 Category: Physics Authors: Heimann, P. Moeller, S. Carbajo, S. Song, S. Dakovski, G. Nordlund, D. Fritz, D. Tags: power meter diagnostics X-ray free electron laser research papers Source Type: research

DA+ data acquisition and analysis software at the Swiss Light Source macromolecular crystallography beamlines
Data acquisition software is an essential component of modern macromolecular crystallography (MX) beamlines, enabling efficient use of beam time at synchrotron facilities. Developed at the Paul Scherrer Institute, the DA+ data acquisition software is implemented at all three Swiss Light Source (SLS) MX beamlines. DA+ consists of distributed services and components written in Python and Java, which communicate via messaging and streaming technologies. The major components of DA+ are the user interface, acquisition engine, online processing and database. Immediate data quality feedback is achieved with distributed automatic ...
Source: Journal of Synchrotron Radiation - December 9, 2017 Category: Physics Authors: Wojdyla, J.A. Kaminski, J.W. Panepucci, E. Ebner, S. Wang, X. Gabadinho, J. Wang, M. Tags: protein crystallography data acquisition software online data analysis beamline automation graphical user interface computer programs Source Type: research

Lead apatites: structural variations among Pb5(BO4)3Cl with B = P (pyromorphite), As (mimetite) and V (vanadinite)
The crystal structure of four Pb apatite samples, Pb5(BO4)3Cl, was refined with synchrotron high-resolution powder X-ray diffraction data, Rietveld refinements, space group P63/m and Z = 2. For this isotypic series, B = P5+ is pyromorphite, B = As5+ is mimetite and B = V5+ is vanadinite. The ionic radius for As5+ (0.355   Å ) is similar to that of V5+ (0.335   Å ), and this is twice as large as that for P5+ (0.170   Å ). However, the c unit-cell parameter for mimetite is surprisingly different from that of vanadinite, although their unit-cell volumes, V, are almost equal to each other. No explanatio...
Source: Journal of Synchrotron Radiation - December 9, 2017 Category: Physics Authors: Antao, S.M. Dhaliwal, I. Tags: lead apatites pyromorphite mimetite vanadinite structure chemistry synchrotron high-resolution powder X-ray diffraction (HRPXRD) Rietveld refinement research papers Source Type: research

Coatings for FEL optics: preparation and characterization of B4C and Pt
Large X-ray mirrors are required for beam transport at both present-day and future free-electron lasers (FELs) and synchrotron sources worldwide. The demand for large mirrors with lengths up to 1   m single layers consisting of light or heavy elements has increased during the last few decades. Accordingly, surface finishing technology is now able to produce large substrate lengths with micro-roughness on the sub-nanometer scale. At the Helmholtz-Zentrum Geesthacht (HZG), a 4.5   m-long sputtering facility enables us to deposit a desired single-layer material some tens of nanometers thick. For the European XFEL project,...
Source: Journal of Synchrotron Radiation - December 7, 2017 Category: Physics Authors: St ö rmer, M. Siewert, F. Horstmann, C. Buchheim, J. Gwalt, G. Tags: FEL X-ray mirrors FEL optics coatings research papers Source Type: research