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Journal of Synchrotron Radiation

Justyna Aleksandra Wojdyla, Jakub W Kaminski, Ezequiel Panepucci, Simon Ebner, Xiaoqiang Wang, Jose Gabadinho, Meitian Wang
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...
January 1, 2018: Journal of Synchrotron Radiation
Jangwoo Kim, Hyo Yun Kim, Jaehyun Park, Sangsoo Kim, Sunam Kim, Seungyu Rah, Jun Lim, Ki Hyun Nam
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 Kirkpatrick-Baez (KB) mirror system that includes an ultra-precision manipulator has been developed...
January 1, 2018: Journal of Synchrotron Radiation
Shigeki Owada, Kazuaki Togawa, Takahiro Inagaki, Toru Hara, Takashi Tanaka, Yasumasa Joti, Takahisa Koyama, Kyo Nakajima, Haruhiko Ohashi, Yasunori Senba, Tadashi Togashi, Kensuke Tono, Mitsuhiro Yamaga, Hirokatsu Yumoto, Makina Yabashi, Hitoshi Tanaka, Tetsuya Ishikawa
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 µJ at a wavelength of 12...
January 1, 2018: Journal of Synchrotron Radiation
Clément Jailin, Martin Poncelet, Stéphane Roux
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...
January 1, 2018: Journal of Synchrotron Radiation
Leonardo Abbene, Fabio Principato, Gaetano Gerardi, Manuele Bettelli, Paul Seller, Matthew C Veale, Nicola Zambelli, Giacomo Benassi, Andrea Zappettini
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 µm, 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-time and reasonable energy resolution at both low and high fluxes...
January 1, 2018: Journal of Synchrotron Radiation
Camila de Lima, Elias Salomão Helou
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...
January 1, 2018: Journal of Synchrotron Radiation
Minas Balyan, Levon Haroutunyan
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...
January 1, 2018: Journal of Synchrotron Radiation
Elena Filatova, Andrey Sokolov
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 2θc. Within angles that are less than the critical angle, both the reflection and refraction strongly distort the shape of the TEY spectrum...
January 1, 2018: Journal of Synchrotron Radiation
Alexey P Oreshko, Elena N Ovchinnikova, Andrei Rogalev, Fabrice Wilhelm, Boris V Mill, Vladimir E Dmitrienko
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...
January 1, 2018: Journal of Synchrotron Radiation
Sytle M Antao, Inayat Dhaliwal
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...
January 1, 2018: Journal of Synchrotron Radiation
Cristian Mocuta, Stefan Stanescu, Manon Gallard, Antoine Barbier, Arkadiusz Dawiec, Bouzid Kedjar, Nicolas Leclercq, Dominique Thiaudiere
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...
January 1, 2018: Journal of Synchrotron Radiation
Andreas Germanos Karydas, Mateusz Czyzycki, Juan José Leani, Alessandro Migliori, Janos Osan, Mladen Bogovac, Pawel Wrobel, Nikita Vakula, Roman Padilla-Alvarez, Ralf Hendrik Menk, Maryam Ghahremani Gol, Matias Antonelli, Manoj K Tiwari, Claudia Caliri, Katarina Vogel-Mikuš, Iain Darby, Ralf Bernd Kaiser
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...
January 1, 2018: Journal of Synchrotron Radiation
Thomas Roth, Wolfgang Freund, Ulrike Boesenberg, Gabriella Carini, Sanghoon Song, Gwenaëlle Lefeuvre, Alexander Goikhman, Martin Fischer, Matthias Schreck, Jan Grünert, Anders Madsen
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 pulse...
January 1, 2018: Journal of Synchrotron Radiation
Bo Yang, Songwei Wang, Juhao Wu
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...
January 1, 2018: Journal of Synchrotron Radiation
Tibebu Alemu, Fu Ming Wang
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 battery performance, as well as for further optimizing the material synthesis routes for advanced battery materials...
January 1, 2018: Journal of Synchrotron Radiation
Y Feng, D W Schafer, S Song, Y Sun, D Zhu, J Krzywinski, A Robert, J Wu, F J Decker
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 was about 17% ± 6% higher than that of the first pulse, revealing lower effective attenuation of the gas cell due to heating by the first pulse and subsequent gas density reduction in the beam path...
January 1, 2018: Journal of Synchrotron Radiation
Siarhei Dziarzhytski, Frank Siewert, Andrey Sokolov, Grzegorz Gwalt, Tino Seliger, Michael Rübhausen, Holger Weigelt, Günter Brenner
The extreme-ultraviolet double-stage imaging Raman spectrometer is a permanent experimental endstation at the plane-grating monochromator beamline branch PG1 at FLASH at DESY in Hamburg, Germany. This unique instrument covers the photon energy range from 20 to 200 eV with high energy resolution of about 2 to 20 meV (design values) featuring an efficient elastic line suppression as well as effective stray light rejection. Such a design enables studies of low-energy excitations like, for example, phonons in solids close to the vicinity of the elastic line...
January 1, 2018: Journal of Synchrotron Radiation
Luca Poletto, Fabio Frassetto, Günter Brenner, Marion Kuhlmann, Elke Plönjes
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 grating...
January 1, 2018: Journal of Synchrotron Radiation
D Spiga
X-ray mirrors with high focusing performances are commonly used in different sectors of science, such as X-ray astronomy, medical imaging and synchrotron/free-electron laser beamlines. While deformations of the mirror profile may cause degradation of the focus sharpness, a deliberate deformation of the mirror can be made to endow the focus with a desired size and distribution, via piezo actuators. The resulting profile can be characterized with suitable metrology tools and correlated with the expected optical quality via a wavefront propagation code or, sometimes, predicted using geometric optics...
January 1, 2018: Journal of Synchrotron Radiation
Michael Störmer, Frank Siewert, Christian Horstmann, Jana Buchheim, Grzegorz Gwalt
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...
January 1, 2018: Journal of Synchrotron Radiation
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