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

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

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

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

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

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

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

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

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

Current events
(Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - October 30, 2017 Category: Physics Authors: , Tags: current events Source Type: research

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

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

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

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

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

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