Refurbishment of an Au-coated toroidal mirror by capacitively coupled RF plasma discharge
Deposition of synchrotron-radiation-induced carbon contamination on beamline optics causes their performance to deteriorate, especially near the carbon K edge. The photon flux losses due to carbon contamination have spurred researchers to search for a suitable decontamination technique to restore the optical surface and retain its performance. Several in situ and ex situ refurbishing strategies for beamline optics are still under development to solve this serious issue. In this work, the carbon contamination is removed from a large (340   mm × 60   mm) Au-coated toroidal mirror surface using a capacitively couple...
Source: Journal of Synchrotron Radiation - May 16, 2019 Category: Physics Authors: Yadav, P.K. Kumar, M. Gupta, R.K. Sinha, M. Chakera, J.A. Modi, M.H. Tags: synchrotron optics carbon contamination RF plasma soft X-ray reflectivity research papers Source Type: research

A beamline-compatible STED microscope for combined visible-light and X-ray studies of biological matter
A dedicated stimulated emission depletion (STED) microscope had been designed and implemented into the G ö ttingen Instrument for Nano-Imaging with X-rays (GINIX) at the synchrotron beamline P10 of the PETRA   III storage ring (DESY, Hamburg). The microscope was installed on the same optical table used for X-ray holography and scanning small-angle X-ray scattering (SAXS). Scanning SAXS was implemented with the Kirkpatrick – Baez (KB) nano-focusing optics of GINIX, while X-ray holography used a combined KB and X-ray waveguide optical system for full-field projection recordings at a defocus position of the objec...
Source: Journal of Synchrotron Radiation - May 16, 2019 Category: Physics Authors: Bernhardt, M. Nicolas, J.-D. Osterhoff, M. Mittelst ä dt, H. Reuss, M. Harke, B. Wittmeier, A. Sprung, M. K ö ster, S. Salditt, T. Tags: STED microscope X-ray holography scanning SAXS correlative microscopy X-ray microscopy in situ STED microscopy research papers Source Type: research

Commissioning of a photoelectron spectrometer for soft X-ray photon diagnostics at the European XFEL
The objective with the instrument is to provide the users and operators with reliable pulse-resolved information regarding photon energy and polarization that opens up a variety of applications for novel experiments but also hardware optimization. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - May 14, 2019 Category: Physics Authors: Laksman, J. Buck, J. Glaser, L. Planas, M. Dietrich, F. Liu, J. Maltezopoulos, T. Scholz, F. Seltmann, J. Hartmann, G. Ilchen, M. Freund, W. Kujala, N. Viefhaus, J. Gr ü nert, J. Tags: photon diagnostics photoelectron spectrometer polarimeter EuXFEL research papers Source Type: research

Multimodal X-ray imaging of grain-level properties and performance in a polycrystalline solar cell
The factors limiting the performance of alternative polycrystalline solar cells as compared with their single-crystal counterparts are not fully understood, but are thought to originate from structural and chemical heterogeneities at various length scales. Here, it is demonstrated that multimodal focused nanobeam X-ray microscopy can be used to reveal multiple aspects of the problem in a single measurement by mapping chemical makeup, lattice structure and charge collection efficiency simultaneously in a working solar cell. This approach was applied to micrometre-sized individual grains in a Cu(In,Ga)Se2 polycrystalline fil...
Source: Journal of Synchrotron Radiation - May 13, 2019 Category: Physics Authors: Ulvestad, A. Hruszkewycz, S.O. Holt, M.V. Hill, M.O. Calvo-Almaz á n, I. Maddali, S. Huang, X. Yan, H. Nazaretski, E. Chu, Y.S. Lauhon, L.J. Rodkey, N. Bertoni, M.I. Stuckelberger, M.E. Tags: solar cell materials scanning nanodiffraction X-ray-beam-induced current multimodal characterization research papers Source Type: research

Probing disorder in high-pressure cubic tin (IV) oxide: a combined X-ray diffraction and absorption study
The transparent conducting oxide, SnO2, is a promising optoelectronic material with predicted tailorable properties via pressure-mediated band gap opening. While such electronic properties are typically modeled assuming perfect crystallinity, disordering of the O sublattice under pressure is qualitatively known. Here a quantitative approach is thus employed, combining extended X-ray absorption fine-structure (EXAFS) spectroscopy with X-ray diffraction, to probe the extent of Sn — O bond anharmonicities in the high-pressure cubic (Pa\bar{3}) SnO2 – formed as a single phase and annealed by CO2 laser heating to 26...
Source: Journal of Synchrotron Radiation - May 13, 2019 Category: Physics Authors: Sneed, D. Kearney, J.S.C. Smith, D. Smith, J.S. Park, C. Salamat, A. Tags: extreme conditions EXAFS XRD laser heating SnO2 diamond anvil cell high pressure research papers Source Type: research

Hard and soft X-ray imaging to resolve human ovarian cortical structures
This study reports the first imaging of human ovarian tissue where the samples consisted of surgically obtained millimetre fragments, properly fixed, stained with osmium tetroxide and included in epoxydic resin. Samples were imaged by the use of propagation phase contrast synchrotron radiation micro-computed tomography (microCT), obtained at the SYRMEP beamline of Elettra light source (Trieste, Italy), and X-ray absorption microCT at the Theoretical Biology MicroCT Imaging Laboratory in Vienna, Austria. The reconstructed microCT images were compared with the soft X-ray absorption and phase contrast images acquired at the T...
Source: Journal of Synchrotron Radiation - May 13, 2019 Category: Physics Authors: Pascolo, L. Sena, G. Gianoncelli, A. Cernogoraz, A. Kourousias, G. Metscher, B.D. Romano, F. Zito, G. Pacil è , S. Barroso, R. Tromba, G. Zweyer, M. Ricci, G. Tags: microtomography phase contrast tomography STXM ovary research papers Source Type: research

Direct measurement of X-ray-induced heating of   microcrystals
Temperature control is a key aspect of macromolecular crystallography, with the technique of cryocooling routinely being used to mitigate X-ray-induced damage. Beam-induced heating could cause the temperature of crystals to rise above the glass transition temperature, greatly increasing the rate of damage. X-ray-induced heating of ruby crystals of 20 – 40   µ m in size has been quantified non-invasively by monitoring the emission wavelengths of X-ray-induced fluorescence during exposure to the X-ray beam. For the beam sizes and dose rates typically used in macromolecular crystallography, the temperature rises...
Source: Journal of Synchrotron Radiation - May 13, 2019 Category: Physics Authors: Warren, A.J. Axford, D. Owen, R.L. Tags: X-ray-induced beam heating fluorescence cryocooling research papers Source Type: research

SwissFEL Aramis beamline photon diagnostics. Erratum
The list of authors in the paper by Jurani ć et al. (2018) [J. Synchrotron Rad. 25, 1238 – 1248] is corrected. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 29, 2019 Category: Physics Authors: Jurani ć , P. Rehanek, J. Arrell, C.A. Pradervand, C. Cassar, A. Calvi, M. Ischebeck, R. Erny, C. Heimgartner, P. Gorgisyan, I. Thominet, V. Tiedtke, K. Sorokin, A. Follath, R. Makita, M. Seniutinas, G. David, C. Milne, C.J. Lemke, H. Radovic, M. Hauri, Tags: FEL physics photon diagnostics instrumentation hard X-rays addenda and errata Source Type: research

Wavefront-propagation simulations supporting the design of a time-delay compensating monochromator beamline at FLASH2
Wavefront-propagation simulations have been performed to complete the design of a monochromator beamline for FLASH2, the variable-gap undulator line at the soft X-ray free-electron laser in Hamburg (FLASH). Prior to propagation through the beamline optical elements, the parameters of the photon source were generated using the GENESIS code which includes the free-electron laser experimental data. Threshold tolerances for the misalignment of mirror angles are calculated and, since diffraction effects were included in the simulations, the minimum quality with respect to the slope errors required for the optics is determined. ...
Source: Journal of Synchrotron Radiation - April 25, 2019 Category: Physics Authors: Ruiz-Lopez, M. Samoylova, L. Brenner, G. Mehrjoo, M. Faatz, B. Kuhlmann, M. Poletto, L. Pl ö njes, E. Tags: wavefront propagation monochromators diffraction gratings ultrafast optics wavefront simulations free-electron lasers beamlines Source Type: research

Photon diagnostics at the FLASH THz beamline
The THz beamline at FLASH, DESY, provides both tunable (1 – 300   THz) narrow-bandwidth ( ∼ 10%) and broad-bandwidth intense (up to 150 uJ) THz pulses delivered in 1   MHz bursts and naturally synchronized with free-electron laser X-ray pulses. Combination of these pulses, along with the auxiliary NIR and VIS ultrashort lasers, supports a plethora of dynamic investigations in physics, material science and biology. The unique features of the FLASH THz pulses and the accelerator source, however, bring along a set of challenges in the diagnostics of their key parameters: pulse energy, spectral, temporal and spat...
Source: Journal of Synchrotron Radiation - April 25, 2019 Category: Physics Authors: Pan, R. Zapolnova, E. Golz, T. Krmpot, A.J. Rabasovic, M.D. Petrovic, J. Asgekar, V. Faatz, B. Tavella, F. Perucchi, A. Kovalev, S. Green, B. Geloni, G. Tanikawa, T. Yurkov, M. Schneidmiller, E. Gensch, M. Stojanovic, N. Tags: FLASH intense THz THz diagnostic electro-optic FTIR research papers Source Type: research

Pump – probe experimental methodology at the Linac Coherent Light Source
Experimental methods that use free-electron laser (FEL) sources that can deliver short X-ray pulses below a 10   fs pulse duration and traditional optical lasers are ideal tools for pump – probe experiments. However, these new methods also come with a unique set of challenges, such as how to accurately determine temporal overlap between two sources at the femtosecond scale and how to correct for the pulse-to-pulse beam property fluctuations of the FEL light derived from the self-amplified spontaneous emission process. Over the past several years of performing pump – probe experiments at the Linac Coherent Lig...
Source: Journal of Synchrotron Radiation - April 25, 2019 Category: Physics Authors: Glownia, J.M. Gumerlock, K. Lemke, H.T. Sato, T. Zhu, D. Chollet, M. Tags: XFELs X-ray free-electron lasers ultrafast lasers pump – probe experiments research papers Source Type: research

Nature of cobalt species during the in situ sulfurization of Co(Ni)Mo/Al2O3 hydrodesulfurization catalysts
The evolution in local structure and electronic properties of cobalt was investigated during in situ sulfurization. Using a combination of 1s X-ray absorption (XAS) and 1s3p resonant inelastic X-ray scattering (RIXS), the valence, coordination and symmetry of cobalt ions were tracked in two cobalt-promoted molybdenum oxide precursors of the hydrodesulfurization catalyst system, namely Co – Mo/Al2O3 and Co – Ni – Mo/Al2O3. Extended X-ray absorption fine structure shows that the Co — O bonds were replaced with Co — S bonds as a function of reaction temperature. The cobalt K pre-edge intensity sh...
Source: Journal of Synchrotron Radiation - April 25, 2019 Category: Physics Authors: al Samarai, M. van Oversteeg, C.H.M. Delgado-Jaime, M.U. Weng, T.- Sokaras, D. Liu, B. van der Linden, M. van der Eerden, A.M.J. Vogt, E.T.C. Weckhuysen, B.M. de Groot, F.M.F. Tags: heterogeneous catalysis hydrodesulfurization (HDS) catalyst systems CoMoS structure hydrotreating catalysts X-ray absorption spectroscopy resonant inelastic X-ray scattering (RIXS) research papers Source Type: research

Characterizing transmissive diamond gratings as beam splitters for the hard X-ray single-shot spectrometer of the European XFEL
The European X-ray Free Electron Laser (EuXFEL) offers intense, coherent femtosecond pulses, resulting in characteristic peak brilliance values a billion times higher than that of conventional synchrotron facilities. Such pulses result in extreme peak radiation levels of the order of terawatts   cm − 2 for any optical component in the beam and can exceed the ablation threshold of many materials. Diamond is considered the optimal material for such applications due to its high thermal conductivity (2052   W   mK − 1 at 300   K) and low absorption for hard X-rays. Grating structures were fabricated on free...
Source: Journal of Synchrotron Radiation - April 25, 2019 Category: Physics Authors: Kujala, N. Makita, M. Liu, J. Zozulya, A. Sprung, M. David, C. Gr ü nert, J. Tags: CVD diamond free-standing diamond membrane X-ray free-electron laser photon diagnostics diffraction efficiency grating structures HIREX diagnostic spectrometer research papers Source Type: research

Probing the spatial coherence of wide X-ray beams with Fresnel mirrors at BL25SU of SPring-8
In this study, a Fresnel-mirror-based optical system was constructed at the soft X-ray beamline (BL25SU) of SPring-8.   The relationship between the coherence and size of the virtual source was quantitatively measured at 300   eV in both the vertical and horizontal directions using the beam. The results obtained indicate that this is a valuable method for the optimization of optical systems along beamlines. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 22, 2019 Category: Physics Authors: Takeo, Y. Motoyama, H. Senba, Y. Kishimoto, H. Ohashi, H. Mimura, H. Tags: spatial coherence Fresnel mirrors soft X-rays research papers Source Type: research

A convolutional neural network for fast upsampling of undersampled tomograms in X-ray CT time-series using a representative highly sampled tomogram
X-ray computed tomography and, specifically, time-resolved volumetric tomography data collections (4D datasets) routinely produce terabytes of data, which need to be effectively processed after capture. This is often complicated due to the high rate of data collection required to capture at sufficient time-resolution events of interest in a time-series, compelling the researchers to perform data collection with a low number of projections for each tomogram in order to achieve the desired `frame rate'. It is common practice to collect a representative tomogram with many projections, after or before the time-critical portion...
Source: Journal of Synchrotron Radiation - April 22, 2019 Category: Physics Authors: Bellos, D. Basham, M. Pridmore, T. French, A.P. Tags: convolutional neural networks projection upsampling sinogram upscaling time-resolved X-ray computed tomography research papers Source Type: research

The SASE1 X-ray beam transport system
SASE1 is the first beamline of the European XFEL that became operational in 2017. It consists of the SASE1 undulator system, the beam transport system, and the two scientific experiment stations: Single Particles, Clusters, and Biomolecules and Serial Femtosecond Crystallography (SPB/SFX), and Femtosecond X-ray Experiments (FXE). The beam transport system comprises mirrors to offset and guide the beam to the instruments and a set of X-ray optical components to align, manipulate and diagnose the beam. The SASE1 beam transport system is described here in its initial configuration, and results and experiences from the first y...
Source: Journal of Synchrotron Radiation - April 16, 2019 Category: Physics Authors: Sinn, H. Dommach, M. Dickert, B. Di Felice, M. Dong, X. Eidam, J. Finze, D. Freijo-Martin, I. Gerasimova, N. Kohlstrunk, N. La Civita, D. Meyn, F. Music, V. Neumann, M. Petrich, M. Rio, B. Samoylova, L. Schmidtchen, S. St ö rmer, M. Trapp, A. Vannoni, M. Tags: XFEL physics photon beamlines hard X-rays beam transport systems X-ray optical components research papers Source Type: research

A middle energy-bandwidth X-ray monochromator for high-flux synchrotron diffraction: revisiting asymmetrically cut silicon crystals
To supply the growing demand for high photon flux in synchrotron science including surface diffraction, a middle energy-bandwidth monochromator covering the 10 − 4 to 10 − 3 range has been adapted by applying an asymmetric diffraction geometry to a cryogenically cooled silicon 111 double-crystal monochromator used as a standard for the undulator source at SPring-8. The asymmetric geometry provides a great advantage with its ability to configure flux gains over a wide energy range by simply changing the asymmetry angle, while the angular divergence of the exit beam remains unchanged. A monolithic design with thr...
Source: Journal of Synchrotron Radiation - April 16, 2019 Category: Physics Authors: Tajiri, H. Yamazaki, H. Ohashi, H. Goto, S. Sakata, O. Ishikawa, T. Tags: X-ray monochromators double-crystal monochromators asymmetric geometry middle energy-bandwidth silicon crystals high-flux diffraction research papers Source Type: research

Laser systems for time-resolved experiments at the Pohang Accelerator Laboratory X-ray Free-Electron Laser beamlines
Optical laser systems for ultrafast X-ray sciences have been established at the Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) beamlines. Three Ti:sapphire regenerative amplifier systems are synchronized to the XFEL with femtosecond precision, and the low temporal jitter of the PAL-XFEL results in an experimental time resolution below 150   fs (full width at half-maximum). A fundamental wave and its harmonics are currently provided for all beamlines, and tunable sources from ultraviolet to near-infrared are available for one beamline. The position stability of the optical laser extracted from the inte...
Source: Journal of Synchrotron Radiation - April 14, 2019 Category: Physics Authors: Kim, M. Min, C.-K. Eom, I. Tags: XFELs time-resolved XFEL experiments optical lasers beamlines amplifier systems fundamental waves Source Type: research

Experimental station Bernina at SwissFEL: condensed matter physics on femtosecond time scales investigated by X-ray diffraction and spectroscopic methods
The Bernina instrument at the SwissFEL Aramis hard X-ray free-electron laser is designed for studying ultrafast phenomena in condensed matter and material science. Ultrashort pulses from an optical laser system covering a large wavelength range can be used to generate specific non-equilibrium states, whose subsequent temporal evolution can be probed by selective X-ray scattering techniques in the range 2 – 12   keV. For that purpose, the X-ray beamline is equipped with optical elements which tailor the X-ray beam size and energy, as well as with pulse-to-pulse diagnostics that monitor the X-ray pulse intensity, pos...
Source: Journal of Synchrotron Radiation - April 14, 2019 Category: Physics Authors: Ingold, G. Abela, R. Arrell, C. Beaud, P. B ö hler, P. Cammarata, M. Deng, Y. Erny, C. Esposito, V. Flechsig, U. Follath, R. Hauri, C. Johnson, S. Juranic, P. Mancini, G.F. Mankowsky, R. Mozzanica, A. Oggenfuss, R.A. Patterson, B.D. Patthey, L. Pedrini, Tags: FEL X-ray pump – probe time-resolved beamlines Source Type: research

Synchrotron radiation micro-tomography for high-resolution neurovascular network morphology investigation
There has been increasing interest in using high-resolution micro-tomography to investigate the morphology of neurovascular networks in the central nervous system, which remain difficult to characterize due to their microscopic size as well as their delicate and complex 3D structure. Synchrotron radiation X-ray imaging, which has emerged as a cutting-edge imaging technology with a high spatial resolution, provides a novel platform for the non-destructive imaging of microvasculature networks at a sub-micrometre scale. When coupled with computed tomography, this technique allows the characterization of the 3D morphology of v...
Source: Journal of Synchrotron Radiation - April 14, 2019 Category: Physics Authors: Cao, Y. Zhang, M. Ding, H. Chen, Z. Tang, B. Wu, T. Xiao, B. Duan, C. Ni, S. Jiang, L. Luo, Z. Li, C. Zhao, J. Liao, S. Yin, X. Fu, Y. Xiao, T. Lu, H. Hu, J. Tags: high-resolution imaging neurovascular network 3D topical reviews Source Type: research

Time-resolved X-ray reflection phases of the nearly forbidden Si(222) reflection under laser excitation
The covalent electron density, which makes Si(222) measurable, is subject to laser excitation. The three-wave Si(222)/(13 {\overline 1}) diffraction at 7.82   keV is used for phase measurements. It is found that laser excitation causes a relative phase change of around 4 ° in Si(222) in the first 100   ps of excitation and this is gradually recovered over several nanoseconds. This phase change is due to laser excitation of covalent electrons around the silicon atoms in the unit cell and makes the electron density deviate further from the centrosymmetric distribution. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 11, 2019 Category: Physics Authors: Tsai, Y.-W. Chang, Y.-Y. Lee, J.-J. Liu, W.-C. Wu, Y.-H. Liu, W.-R. Liu, H.-Y. Lee, K.-Y. Weng, S.-C. Sheu, H.-S. Chiu, M.-S. Lee, Y.-Y. Hsu, C.-H. Chang, S.-L. Tags: pump – probe experiments X-ray reflection phases three-wave diffraction laser excitation covalent electron density research papers Source Type: research

Angular dispersion enhanced prebunch for seeding ultrashort and coherent EUV and soft X-ray free-electron laser in storage rings
Prebunching is an effective technique to reduce the radiation saturation length and to improve the longitudinal coherence and output stability in storage-ring-based free-electron lasers (FELs). A novel technique is proposed which uses angular dispersion to enhance the high-harmonic bunching with very small laser-induced energy spread. This technique can effectively reduce the radiation saturation length without significantly reducing the peak power of the FEL. Numerical simulations demonstrate that this technique can be used for the generation of 100   MW scale level, fully temporal coherent femtosecond extreme-ultraviol...
Source: Journal of Synchrotron Radiation - April 11, 2019 Category: Physics Authors: Wang, X. Feng, C. Liu, T. Zhang, Z. Tsai, C.-Y. Wu, J. Yang, C. Zhao, Z. Tags: angular dispersion storage rings free-electron lasers extreme-ultraviolet (EUV) ultrashort prebunching high-harmonic bunching radiation saturation length research papers Source Type: research

The Single Particles, Clusters and Biomolecules and Serial Femtosecond Crystallography instrument of the European XFEL: initial installation
The European X-ray Free-Electron Laser (FEL) became the first operational high-repetition-rate hard X-ray FEL with first lasing in May 2017. Biological structure determination has already benefitted from the unique properties and capabilities of X-ray FELs, predominantly through the development and application of serial crystallography. The possibility of now performing such experiments at data rates more than an order of magnitude greater than previous X-ray FELs enables not only a higher rate of discovery but also new classes of experiments previously not feasible at lower data rates. One example is time-resolved experim...
Source: Journal of Synchrotron Radiation - April 11, 2019 Category: Physics Authors: Mancuso, A.P. Aquila, A. Batchelor, L. Bean, R.J. Bielecki, J. Borchers, G. Doerner, K. Giewekemeyer, K. Graceffa, R. Kelsey, O.D. Kim, Y. Kirkwood, H.J. Legrand, A. Letrun, R. Manning, B. Lopez Morillo, L. Messerschmidt, M. Mills, G. Raabe, S. Reimers, N Tags: XFEL serial crystallography instrumentation research papers Source Type: research

Compact undulator line for a high-brilliance soft-X-ray free-electron laser at MAX IV
This study focuses on FEL operation with a shorter undulator period and higher undulator strength made available through recent developments in in-vacuum, cryogenic and superconducting undulators. Progress on short-period undulator technologies is surveyed and FEL output characteristics versus undulator parameters are computed. The study is performed on a case of the planned soft-X-ray FEL at the MAX IV Laboratory in Sweden. An extension of the SASE mode into the harmonic lasing self-seeded mode is also analysed. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 10, 2019 Category: Physics Authors: Mak, A. Sal é n, P. Goryashko, V. Tags: undulator technologies X-ray free-electron lasers high brilliance self-amplified spontaneous emission harmonic lasing self-seeding beamlines Source Type: research

Native mass spectrometry provides sufficient ion flux for XFEL single-particle imaging
The SPB/SFX instrument at the European XFEL provides unique conditions for single-particle imaging (SPI) experiments due to its high brilliance, nano-focus and unique pulse structure. Promising initial results provided by the international LCLS (Linac Coherent Light Source) SPI initiative highlight the potential of SPI. Current available injection methods generally have high sample consumption and do not provide any options for pulsing, selection or orientation of particles, which poses a problem for data evaluation. Aerosol-injector-based sample delivery is the current method of choice for SPI experiments, although, to a ...
Source: Journal of Synchrotron Radiation - April 10, 2019 Category: Physics Authors: Uetrecht, C. Lorenzen, K. Kitel, M. Heidemann, J. Spencer, J.H. Schl ü ter, H. Schulz, J. Tags: SPI electrospray Ionization X-ray free-electron lasers native MS structural biology research papers Source Type: research

Dynamical effects on superradiant THz emission from an undulator
Superradiant emission occurs when ultra-relativistic electron bunches are compressed to a duration shorter than the wavelength of the light emitted by them. In this case the different electron contributions to the emitted field sum up in phase and the output intensity scales as the square of the number of electrons in the bunch. In this work the particular case of superradiant emission from an undulator in the THz frequency range is considered. An electron bunch at the entrance of a THz undulator setup has typically an energy chirp because of the necessity to compress it in magnetic chicanes. Then, the chirped electron bun...
Source: Journal of Synchrotron Radiation - April 10, 2019 Category: Physics Authors: Geloni, G. Tanikawa, T. Tomin, S. Tags: undulator radiation superradiant emission chirped electron bunch dispersion research papers Source Type: research

Reaction microscope endstation at FLASH2
A reaction microscope dedicated to multi-particle coincidence spectroscopy on gas-phase samples is installed at beamline FL26 of the free-electron laser FLASH2 in Hamburg. The main goals of the instrument are to follow the dynamics of atoms, molecules and small clusters on their natural time-scale and to study non-linear light – matter interaction with such systems. To this end, the reaction microscope is combined with an in-line extreme-ultraviolet (XUV) split-delay and focusing optics, which allows time-resolved XUV-XUV pump – probe spectroscopy to be performed. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 8, 2019 Category: Physics Authors: Schmid, G. Schnorr, K. Augustin, S. Meister, S. Lindenblatt, H. Trost, F. Liu, Y. Braune, M. Treusch, R. Schr ö ter, C.D. Pfeifer, T. Moshammer, R. Tags: time-resolved molecular dynamics non-linear light – matter interaction reaction microscope multi-particle coincidence spectroscopy free-electron laser XUV XUV pump probe spectroscopy beamlines Source Type: research

A flexible cell for in situ combined XAS – DRIFTS – MS experiments
A new cell for in situ combined X-ray absorption, diffuse reflectance IR Fourier transform and mass spectroscopies (XAS – DRIFTS – MS) is presented. The cell stands out among others for its achievements and flexibility. It is possible to perform XAS measurements in transmission or fluorescence modes, and the cell is compatible with external devices like UV-light and Raman probes. It includes different sample holders compatible with the different XAS detection modes, different sample forms (free powder or self-supporting pellet) and different sample loading/total absorption. Additionally, it has a small dead vol...
Source: Journal of Synchrotron Radiation - April 8, 2019 Category: Physics Authors: Meira, D.M. Monte, M. Fern á ndez-Garc í a, M. Meunier, F. Mathon, O. Pascarelli, S. Agostini, G. Tags: fluorescence mode multi-technique characterization in situ characterization coupled experiments XAS – DRIFTS MS research papers Source Type: research

A piezoelectric deformable X-ray mirror for phase compensation based on global optimization
As a strong tool for the study of nanoscience, the synchrotron hard X-ray nanoprobe technique enables researchers to investigate complex samples with many advantages, such as in   situ setup, high sensitivity and the integration of various experimental methods. In recent years, an important goal has been to push the focusing spot size to the diffraction limit of ∼ 10   nm. The multilayer-based Kirkpatrick – Baez (KB) mirror system is one of the most important methods used to achieve this goal. This method was chosen by the nanoprobe beamline of the Phase-II project at the Shanghai Synchrotron Radiation Facili...
Source: Journal of Synchrotron Radiation - April 8, 2019 Category: Physics Authors: Jiang, H. Tian, N. Liang, D. Du, G. Yan, S. Tags: piezoelectric deformable mirror phase compensation figure error speckle scanning metrology iterative global optimization research papers Source Type: research

A statistical approach to correct X-ray response non-uniformity in microstrip detectors for high-accuracy and high-resolution total-scattering measurements
An unbiased approach to correct X-ray response non-uniformity in microstrip detectors has been developed based on the statistical estimation that the scattering intensity at a fixed angle from an object is expected to be constant within the Poisson noise. Raw scattering data of SiO2 glass measured by a microstrip detector module was found to show an accuracy of 12 σ PN at an intensity of 106 photons, where σ PN is the standard deviation according to the Poisson noise. The conventional flat-field calibration has failed in correcting the data, whereas the alternative approach used in this article successfully imp...
Source: Journal of Synchrotron Radiation - April 4, 2019 Category: Physics Authors: Kato, K. Tanaka, Y. Yamauchi, M. Ohara, K. Hatsui, T. Tags: total scattering pair distribution functions microstrip detectors flat-field calibration Poisson noise research papers Source Type: research

Depth-resolved compositional analysis of W/B4C multilayers using resonant soft X-ray reflectivity
W/B4C multilayers (MLs) consisting of ten layer pairs with varying boron carbide layer thicknesses have been investigated. The ML structures were characterized using grazing-incidence hard X-ray reflectivity (GIXR), resonant soft X-ray reflectivity (RSXR), hard X-ray photoelectron spectroscopy (HAXPES) and X-ray absorption near-edge spectroscopy (XANES). Depth-resolved spectroscopic information on the boron carbide layer in W/B4C MLs was extracted with sub-nanometre resolution using reflectivity performed in the vicinity of the B K-edge. Interestingly, these results show that the composition of boron carbide films is stron...
Source: Journal of Synchrotron Radiation - April 4, 2019 Category: Physics Authors: Rao, P.N. Goutam, U.K. Kumar, P. Gupta, M. Ganguli, T. Rai, S.K. Tags: X-ray multilayers extreme ultraviolet lithography optical index composition boron carbide resonant reflectivity research papers Source Type: research

A simple instrument to find spatiotemporal overlap of optical/X-ray light at free-electron lasers
A compact and robust diagnostic to determine spatial and temporal overlap between X-ray free-electron laser and optical laser pulses was developed and evaluated using monochromatic X-rays from the Linac Coherent Light Source. It was used to determine temporal overlap with a resolution of ∼ 10   fs, despite the large pulse energy fluctuations of the monochromatic X-ray pulses, and covers a wide optical wavelength range from ultraviolet to near-infrared with a single configuration. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 4, 2019 Category: Physics Authors: Sato, T. Glownia, J.M. Ware, M.R. Chollet, M. Nelson, S. Zhu, D. Tags: X-ray free-electron lasers optical laser pulses pump-probe experiments spatial overlap temporal overlap research papers Source Type: research

A kinetic and mechanistic study into the transformation of calcium sulfate hemihydrate to dihydrate
The conversion of CaSO4 · 0.5H2O to CaSO4 · 2H2O is of great importance industrially, being the reaction behind plasterboard production and the setting of medical plasters. A detailed kinetic and mechanistic study of this process was conducted using time-resolved synchrotron X-ray diffraction in this work. The CaSO4 · 2H2O product is very similar regardless of whether the α - or β -form of CaSO4 · 0.5H2O is used as the starting material, but the reaction process is very different. The induction time is usually shorter for α -CaSO4 · 0.5H2O than β -CaSO4 · 0.5H...
Source: Journal of Synchrotron Radiation - April 4, 2019 Category: Physics Authors: Gurgul, S.J. Seng, G. Williams, G.R. Tags: gypsum calcium sulfate hemihydrate hydration conversion research papers Source Type: research

Very high brightness and power LCLS-II hard X-ray pulses
The feasibility of generating X-ray pulses in the 4 – 8   keV fundamental photon energy range with 0.65   TW peak power, 15   fs pulse duration and 9 × 10 − 5 bandwidth using the LCLS-II copper linac and hard X-ray (HXR) undulator is shown. In addition, third-harmonic pulses with 8 – 12   GW peak power and narrow bandwidth are also generated. High-power and small-bandwidth X-rays are obtained using two electron bunches separated by about 1   ns, one to generate a high-power seed signal, the other to amplify it through the process of the HXR undulator tapering. The bunch delay is compensate...
Source: Journal of Synchrotron Radiation - April 3, 2019 Category: Physics Authors: Halavanau, A. Decker, F.-J. Emma, C. Sheppard, J. Pellegrini, C. Tags: FEL fresh-bunch FEL terawatt FEL research papers Source Type: research

Fast three-dimensional phase retrieval in propagation-based X-ray tomography
The following article describes a method for 3D reconstruction of multi-material objects based on propagation-based X-ray phase-contrast tomography (PB-CT) with phase retrieval using the homogeneous form of the transport of intensity equation (TIE-Hom). Unlike conventional PB-CT algorithms that perform phase retrieval of individual projections, the described post-reconstruction phase-retrieval method is applied in 3D to a localized region of the CT-reconstructed volume. This work demonstrates, via numerical simulations, the accuracy and noise characteristics of the method under a variety of experimental conditions, compari...
Source: Journal of Synchrotron Radiation - April 1, 2019 Category: Physics Authors: Thompson, D.A. Nesterets, Y.I. Pavlov, K.M. Gureyev, T.E. Tags: phase contrast computed tomography reconstruction X-ray imaging research papers Source Type: research

A high-throughput energy-dispersive tender X-ray spectrometer for shot-to-shot sulfur measurements
An X-ray emission spectrometer that can detect the sulfur K α emission lines with large throughput and a high energy resolution is presented. The instrument is based on a large d-spacing perfect Bragg analyzer that diffracts the sulfur K α emission at close to backscattering angles. This facilitates the application of efficient concepts routinely employed in hard X-ray spectrometers towards the tender X-ray regime. The instrument described in this work is based on an energy-dispersive von Hamos geometry that is well suited for photon-in photon-out spectroscopy at X-ray free-electron laser and synchrotron source...
Source: Journal of Synchrotron Radiation - April 1, 2019 Category: Physics Authors: Abraham, B. Nowak, S. Weninger, C. Armenta, R. Defever, J. Day, D. Carini, G. Nakahara, K. Gallo, A. Nelson, S. Nordlund, D. Kroll, T. Hunter, M.S. van Driel, T. Zhu, D. Weng, T.-C. Alonso-Mori, R. Sokaras, D. Tags: X-ray emission spectroscopy tender X-rays X-ray absorption spectroscopy X-ray free-electron lasers photon-in photon-out spectroscopy methods research papers Source Type: research

Design and performance of a new setup for spatially resolved transmission X-ray photoelectron spectroscopy at the Swiss Light Source
The successful design, installation and operation of a high spatial resolution X-ray photoelectron spectrometer at the Swiss Light Source is presented. In this instrument, a Fresnel zone plate is used to focus an X-ray beam onto the sample and an electron analyzer positioned at 45 ° with respect to the incoming beam direction is used to collect photoelectrons from the backside of the sample. By raster scanning the sample, transmitted current, X-ray absorption and X-ray photoemission maps can be simultaneously acquired. This work demonstrates that chemical information can be extracted with micrometre resolution; the res...
Source: Journal of Synchrotron Radiation - April 1, 2019 Category: Physics Authors: Roy, K. Raabe, J. Schifferle, P. Finizio, S. Kleibert, A. van Bokhoven, J.A. Artiglia, L. Tags: X-ray spectromicroscopy spatial resolution X-ray photoelectron spectroscopy scanning transmission X-ray microscope research papers Source Type: research

Arrival timing diagnostics at a soft X-ray free-electron laser beamline of SACLA BL1
An arrival timing monitor for the soft X-ray free-electron laser (XFEL) beamline of SACLA BL1 has been developed. A small portion of the soft XFEL pulse is branched using the wavefront-splitting method. The branched FEL pulse is one-dimensionally focused onto a GaAs wafer to induce a transient reflectivity change. The beam branching method enables the simultaneous operation of the arrival timing diagnostics and experiments. The temporal resolution evaluated from the imaging system is ∼ 22   fs in full width at half-maximum, which is sufficient considering the temporal durations of the soft XFEL and the optical laser ...
Source: Journal of Synchrotron Radiation - March 31, 2019 Category: Physics Authors: Owada, S. Nakajima, K. Togashi, T. Katayama, T. Yumoto, H. Ohashi, H. Yabashi, M. Tags: soft X-ray free-electron lasers arrival timing diagnostics beamlines Source Type: research

On-line monitoring of the spatial properties of hard X-ray free-electron lasers based on a grating splitter
X-ray free-electron lasers (XFELs) play an increasingly important role in addressing the new scientific challenges relating to their high brightness, high coherence and femtosecond time structure. As a result of pulse-by-pulse fluctuations, the pulses of an XFEL beam may demonstrate subtle differences in intensity, energy spectrum, coherence, wavefront, etc., and thus on-line monitoring and diagnosis of a single pulse are required for many XFEL experiments. Here a new method is presented, based on a grating splitter and bending-crystal analyser, for single-pulse on-line monitoring of the spatial characteristics including t...
Source: Journal of Synchrotron Radiation - March 31, 2019 Category: Physics Authors: Hua, W. Zhou, G. Hu, Z. Yang, S. Liao, K. Zhou, P. Dong, X. Wang, Y. Bian, F. Wang, J. Tags: XFEL X-ray optics grating diffraction research papers Source Type: research

Structure, stress and optical properties of Cr/C multilayers for the tender X-ray range
Cr/C multilayer optics are a suitable choice for the tender X-ray range (1 – 4   keV) that covers the K absorption edges of P, S, Cl and 3d transition metals as well as the L absorption edges of 4d transition metals. In particular, these optics are studied in order to optimize the optical properties of collimated plane-grating monochromators. In this paper, the structure, stress and optical properties of Cr/C multilayers (fabricated using direct-current magnetron sputtering) with bi-layer number of 20 and the same period (about 11.64   nm) but different Cr thickness ratio (0.20 – 0.80) are investigated. Fir...
Source: Journal of Synchrotron Radiation - March 31, 2019 Category: Physics Authors: Feng, J. Huang, Q. Wang, H. Yang, X. Giglia, A. Xie, C. Wang, Z. Tags: X-ray optics Cr/C multilayer structure stress high reflectivity research papers Source Type: research

Optical performance and radiation stability of polymer X-ray refractive nano-lenses
This article also discusses issues related to lens aberrations, astigmatism and radiation stability, and thus ways of improving the lens further are considered. Polymer nano-lenses are versatile and are promissing for nano-focusing and compact X-ray microscopy. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - March 31, 2019 Category: Physics Authors: Barannikov, A. Polikarpov, M Ershov, P Bessonov, V Abrashitova, K Snigireva, I Yunkin, V Bourenkov, G Schneider, T Fedyanin, A. A Snigirev, A Tags: full-field X-ray microscopy X-ray refractive lenses additive manufacturing research papers Source Type: research

Phenomenological and numerical analysis of power evolution and bunching in single-pass X-ray FELs. Erratum
A correction is made to the paper by Zhukovsky& Kalitenko (2019). [J. Synchrotron Rad. 26, 159 – 169]. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 27, 2019 Category: Physics Authors: Zhukovsky, K. Kalitenko, A. Tags: undulator radiation two-frequency undulator harmonic generation free-electron laser addenda and errata Source Type: research

A comparison of absorption and phase contrast for X-ray imaging of biological cells. Erratum
An error in the calculation for X-ray absorption imaging has been identified in the paper by Nave (2018) [J. Synchrotron Rad. 25, 1490 – 1504]. The required fluence and dose in the paper are a factor of ten too low for this mode of imaging. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 27, 2019 Category: Physics Authors: Nave, C. Tags: X-ray imaging biological cells dose and fluence requirements addenda and errata Source Type: research

Fluorescence intensity monitors as intensity and beam-position diagnostics for X-ray free-electron lasers
For LCLS-II, a fluorescence intensity monitor for the non-invasive, pulse-by-pulse normalization of experiments has been developed. A prototype diagnostic was constructed with a microchannel plate assembly and two photodiodes. The diagnostic was then installed in the LCLS SXR instrument Kirkpatrick – Baez mirror chamber with the detectors located above the vertically reflecting mirror. The linearity, noise and position sensitivity of the detectors have been characterized. The photodiode responsivity is suitable for high pulse energies. The microchannel plate detector shows sufficient responsivity over a wide range of...
Source: Journal of Synchrotron Radiation - February 22, 2019 Category: Physics Authors: Heimann, P. Reid, A. Feng, Y. Fritz, D. Tags: X-ray intensity monitor diagnostics X-ray free-electron laser research papers Source Type: research

Multiple-beamline operation of SACLA
The SPring-8 Å ngstrom Compact free-electron LAser (SACLA) began parallel operation of three beamlines (BL1 – 3) in autumn 2017 to increase the user beam time of the X-ray free-electron laser. The success of the multiple-beamline operation is based on two technological achievements: (i) the fast switching operation of the SACLA main linear accelerator, which provides BL2 and BL3 with pulse-by-pulse electron beams, and (ii) the relocation and upgrade of the SPring-8 Compact SASE Source for BL1, for the generation of a soft X-ray free-electron laser. Moreover, the photon beamlines and experimental stations were u...
Source: Journal of Synchrotron Radiation - February 22, 2019 Category: Physics Authors: Tono, K. Hara, T. Yabashi, M. Tanaka, H. Tags: X-ray free-electron laser SACLA multiple-beamline operation SCSS photon beamline beamlines Source Type: research

The Nanodiffraction beamline ID01/ESRF: a microscope for imaging strain and structure
The ID01 beamline has been built to combine Bragg diffraction with imaging techniques to produce a strain and mosaicity microscope for materials in their native or operando state. A scanning probe with nano-focused beams, objective-lens-based full-field microscopy and coherent diffraction imaging provide a suite of tools which deliver micrometre to few nanometre spatial resolution combined with 10 − 5 strain and 10 − 3 tilt sensitivity. A detailed description of the beamline from source to sample is provided and serves as a reference for the user community. The anticipated impact of the impending upgrade to the...
Source: Journal of Synchrotron Radiation - February 22, 2019 Category: Physics Authors: Leake, S.J. Chahine, G.A. Djazouli, H. Zhou, T. Richter, C. Hilhorst, J. Petit, L. Richard, M.-I. Morawe, C. Barrett, R. Zhang, L. Homs-Regojo, R.A. Favre-Nicolin, V. Boesecke, P. Sch ü lli, T.U. Tags: X-ray full-field microscopy scanning microscopy Bragg diffraction coherent diffraction imaging beamlines Source Type: research

An experimental platform using high-power, high-intensity optical lasers with the hard X-ray free-electron laser at SACLA
An experimental platform using X-ray free-electron laser (XFEL) pulses with high-intensity optical laser pulses is open for early users' experiments at the SACLA XFEL facility after completion of the commissioning. The combination of the hard XFEL and the high-intensity laser provides capabilities to open new frontiers of laser-based high-energy-density science. During the commissioning phase, characterization of the XFEL and the laser at the platform has been carried out for the combinative utilization as well as the development of instruments and basic diagnostics for user experiments. An overview of the commissioning an...
Source: Journal of Synchrotron Radiation - February 22, 2019 Category: Physics Authors: Yabuuchi, T. Kon, A. Inubushi, Y. Togahi, T. Sueda, K. Itoga, T. Nakajima, K. Habara, H. Kodama, R. Tomizawa, H. Yabashi, M. Tags: X-ray free-electron laser high-intensity optical laser high-energy density science SACLA beamlines Source Type: research

MXCuBE2: the dawn of MXCuBE Collaboration
MXCuBE2 is the second-generation evolution of the MXCuBE beamline control software, initially developed and used at ESRF – the European Synchrotron. MXCuBE2 extends, in an intuitive graphical user interface (GUI), the functionalities and data collection methods available to users while keeping all previously available features and allowing for the straightforward incorporation of ongoing and future developments. MXCuBE2 introduces an extended abstraction layer that allows easy interfacing of any kind of macromolecular crystallography (MX) hardware component, whether this is a diffractometer, sample changer, detector ...
Source: Journal of Synchrotron Radiation - February 22, 2019 Category: Physics Authors: Oscarsson, M. Beteva, A. Flot, D. Gordon, E. Guijarro, M. Leonard, G. McSweeney, S. Monaco, S. Mueller-Dieckmann, C. Nanao, M. Nurizzo, D. Popov, A. von Stetten, D. Svensson, O. Rey-Bakaikoa, V. Chado, I. Chavas, L. Gadea, L. Gourhant, P. Isabet, T. Legra Tags: macromolecular crystallography synchrotron beamline control software software collaboration graphical user interface MXCuBE research papers Source Type: research

The Macromolecular Femtosecond Crystallography Instrument at the Linac Coherent Light Source
The Macromolecular Femtosecond Crystallography (MFX) instrument at the Linac Coherent Light Source (LCLS) is the seventh and newest instrument at the world's first hard X-ray free-electron laser. It was designed with a primary focus on structural biology, employing the ultrafast pulses of X-rays from LCLS   at atmospheric conditions to overcome radiation damage limitations in biological measurements. It is also capable of performing various time-resolved measurements. The MFX design consists of a versatile base system capable of supporting multiple methods, techniques and experimental endstations. The primary techniqu...
Source: Journal of Synchrotron Radiation - February 22, 2019 Category: Physics Authors: Sierra, R.G. Batyuk, A. Sun, Z. Aquila, A. Hunter, M.S. Lane, T.J. Liang, M. Yoon, C.H. Alonso-Mori, R. Armenta, R. Castagna, J.-C. Hollenbeck, M. Osier, T.O. Hayes, M. Aldrich, J. Curtis, R. Koglin, J.E. Rendahl, T. Rodriguez, E. Carbajo, S. Guillet, S. Tags: X-ray free-electron laser serial femtosecond crystallography protein crystallography time-resolved crystallography room-temperature crystallography X-ray FEL research papers Source Type: research

A versatile liquid-jet setup for the European XFEL
The SPB/SFX instrument of the European XFEL provides unique possibilities for high-throughput serial femtosecond crystallography. This publication presents the liquid-jet sample delivery setup of this instrument. The setup is compatible with state-of-the-art gas dynamic virtual nozzle systems as well as high-viscosity extruders and provides space and flexibility for other liquid injection devices and future upgrades. The liquid jets are confined in a differentially pumped catcher assembly and can be replaced within a couple of minutes through a load-lock. A two-microscope imaging system allows visual control of the jets fr...
Source: Journal of Synchrotron Radiation - February 22, 2019 Category: Physics Authors: Schulz, J. Bielecki, J. Doak, R.B. D ö rner, K. Graceffa, R. Shoeman, R.L. Sikorski, M. Thute, P. Westphal, D. Mancuso, A.P. Tags: FEL physics instrumentation liquid jets sample delivery research papers Source Type: research