Photon-in photon-out hard X-ray spectroscopy at the Linac Coherent Light Source
X-ray free-electron lasers (FELs) have opened unprecedented possibilities to study the structure and dynamics of matter at an atomic level and ultra-fast timescale. Many of the techniques routinely used at storage ring facilities are being adapted for experiments conducted at FELs. In order to take full advantage of these new sources several challenges have to be overcome. They are related to the very different source characteristics and its resulting impact on sample delivery, X-ray optics, X-ray detection and data acquisition. Here it is described how photon-in photon-out hard X-ray spectroscopy techniques can be applied...
Source: Journal of Synchrotron Radiation - April 15, 2015 Category: Physics Authors: Alonso-Mori, R.Sokaras, D.Zhu, D.Kroll, T.Chollet, M.Feng, Y.Glownia, J.M.Kern, J.Lemke, H.T.Nordlund, D.Robert, A.Sikorski, M.Song, S.Weng, T.-C.Bergmann, U. Tags: FEL hard X-ray emission spectroscopy XES XRS research papers Source Type: research

Nanofocusing of X-ray free-electron lasers by grazing-incidence reflective optics
Total-reflection mirror devices for X-ray free-electron laser focusing are discussed in terms of optical design, mirror-fabrication technology, a wavefront diagnosis method and radiation-damage testing, as a review of the present status of the focusing optics at the SPring-8 angstrom compact free-electron laser (SACLA). Designed beam sizes of 1 µm and 50 nm, and spot sizes almost matching prediction have been achieved and used to explore topics at the forefront of natural science. The feasibility of these devices is determined to be sufficient for long-term and stable operation at SACLA by investigating the radia...
Source: Journal of Synchrotron Radiation - April 15, 2015 Category: Physics Authors: Yamauchi, K.Yabashi, M.Ohashi, H.Koyama, T.Ishikawa, T. Tags: nanofocusing X-ray free-electron laser KB mirror phase diagnosis research papers Source Type: research

Beamline P02.1 at PETRA III for high-resolution and high-energy powder diffraction
Powder X-ray diffraction techniques largely benefit from the superior beam quality provided by high-brilliance synchrotron light sources in terms of photon flux and angular resolution. The High Resolution Powder Diffraction Beamline P02.1 at the storage ring PETRA III (DESY, Hamburg, Germany) combines these strengths with the power of high-energy X-rays for materials research. The beamline is operated at a fixed photon energy of 60 keV (0.207 Å wavelength). A high-resolution monochromator generates the highly collimated X-ray beam of narrow energy bandwidth. Classic crystal structure determination in reciprocal s...
Source: Journal of Synchrotron Radiation - April 14, 2015 Category: Physics Authors: Dippel, A.-C.Liermann, H.-P.Delitz, J.T.Walter, P.Schulte-Schrepping, H.Seeck, O.H.Franz, H. Tags: synchrotron powder diffraction high-energy X-rays high angular resolution time-resolved experiments X-ray total scattering research papers Source Type: research

Soft X-ray angle-resolved photoemission with micro-positioning techniques for metallic V2O3
Soft X-ray angle-resolved photoemission has been performed for metallic V2O3. By combining a microfocus beam (40 µm × 65 µm) and micro-positioning techniques with a long-working-distance microscope, it has been possible to observe band dispersions from tiny cleavage surfaces with a typical size of several tens of µm. The photoemission spectra show a clear position dependence, reflecting the morphology of the cleaved sample surface. By selecting high-quality flat regions on the sample surface, it has been possible to perform band mapping using both photon-energy and polar-angle dependences, openi...
Source: Journal of Synchrotron Radiation - April 14, 2015 Category: Physics Authors: Fujiwara, H.Kiss, T.Wakabayashi, Y.K.Nishitani, Y.Mori, T.Nakata, Y.Kitayama, S.Fukushima, K.Ikeda, S.Fuchimoto, H.Minowa, Y.Mo, S.-K.Denlinger, J.D.Allen, J.W.Metcalf, P.Imai, M.Yoshimura, K.Suga, S.Muro, T.Sekiyama, A. Tags: angle-resolved photoemission spectroscopy (ARPES) soft X-ray micro-positioning strongly correlated oxide research papers Source Type: research

Pulse energy measurement at the SXR instrument
A gas monitor detector was implemented and characterized at the Soft X-ray Research (SXR) instrument to measure the average, absolute and pulse-resolved photon flux of the LCLS beam in the energy range between 280 and 2000 eV. The detector is placed after the monochromator and addresses the need to provide reliable absolute pulse energy as well as pulse-resolved measurements for the various experiments at this instrument. This detector provides a reliable non-invasive measurement for determining flux levels on the samples in the downstream experimental chamber and for optimizing signal levels of secondary detectors and f...
Source: Journal of Synchrotron Radiation - April 14, 2015 Category: Physics Authors: Moeller, S.Brown, G.Dakovski, G.Hill, B.Holmes, M.Loos, J.Maida, R.Paiser, E.Schlotter, W.Turner, J.J.Wallace, A.Jastrow, U.Kreis, S.Sorokin, A.A.Tiedtke, K. Tags: FEL diagnostics pulse energy detector research papers Source Type: research

Focus characterization at an X-ray free-electron laser by coherent scattering and speckle analysis
X-ray focus optimization and characterization based on coherent scattering and quantitative speckle size measurements was demonstrated at the Linac Coherent Light Source. Its performance as a single-pulse free-electron laser beam diagnostic was tested for two typical focusing configurations. The results derived from the speckle size/shape analysis show the effectiveness of this technique in finding the focus' location, size and shape. In addition, its single-pulse compatibility enables users to capture pulse-to-pulse fluctuations in focus properties compared with other techniques that require scanning and averaging. (Sourc...
Source: Journal of Synchrotron Radiation - April 14, 2015 Category: Physics Authors: Sikorski, M.Song, S.Schropp, A.Seiboth, F.Feng, Y.Alonso-Mori, R.Chollet, M.Lemke, H.T.Sokaras, D.Weng, T.-C.Zhang, W.Robert, A.Zhu, D. Tags: X-ray FEL speckle focusing research papers Source Type: research

The X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source
The X-ray Correlation Spectroscopy instrument is dedicated to the study of dynamics in condensed matter systems using the unique coherence properties of free-electron lasers. It covers a photon energy range of 4–25 keV. The intrinsic temporal characteristics of the Linac Coherent Light Source, in particular the 120 Hz repetition rate, allow for the investigation of slow dynamics (milliseconds) by means of X-ray photon correlation spectroscopy. Double-pulse schemes could probe dynamics on the picosecond timescale. A description of the instrument capabilities and recent achievements is presented. (Source: Journal o...
Source: Journal of Synchrotron Radiation - April 14, 2015 Category: Physics Authors: Alonso-Mori, R.Caronna, C.Chollet, M.Curtis, R.Damiani, D.S.Defever, J.Feng, Y.Flath, D.L.Glownia, J.M.Lee, S.Lemke, H.T.Nelson, S.Bong, E.Sikorski, M.Song, S.Srinivasan, V.Stefanescu, D.Zhu, D.Robert, A. Tags: FEL hard X-ray XPCS coherent scattering research papers Source Type: research

UV-CD12: synchrotron radiation circular dichroism beamline at ANKA
Synchrotron radiation circular dichroism (SRCD) is a rapidly growing technique for structure analysis of proteins and other chiral biomaterials. UV-CD12 is a high-flux SRCD beamline installed at the ANKA synchrotron, to which it had been transferred after the closure of the SRS Daresbury. The beamline covers an extended vacuum-UV to near-UV spectral range and has been open for users since October 2011. The current end-station allows for temperature-controlled steady-state SRCD spectroscopy, including routine automated thermal scans of microlitre volumes of water-soluble proteins down to 170 nm. It offers an excellent sig...
Source: Journal of Synchrotron Radiation - April 11, 2015 Category: Physics Authors: Bürck, J.Roth, S.Windisch, D.Wadhwani, P.Moss, D.Ulrich, A.S. Tags: synchrotron radiation circular dichroism (SRCD) vacuum-UV secondary structure proteins alignment of membrane-active peptides oriented CD (OCD) of anisotropic samples beamlines Source Type: research

Characterization and use of the spent beam for serial operation of LCLS
X-ray free-electron laser sources such as the Linac Coherent Light Source offer very exciting possibilities for unique research. However, beam time at such facilities is very limited and in high demand. This has led to significant efforts towards beam multiplexing of various forms. One such effort involves re-using the so-called spent beam that passes through the hole in an area detector after a weak interaction with a primary sample. This beam can be refocused into a secondary interaction region and used for a second, independent experiment operating in series. The beam profile of this refocused beam was characterized for...
Source: Journal of Synchrotron Radiation - April 11, 2015 Category: Physics Authors: Boutet, S.Foucar, L.Barends, T.R.M.Botha, S.Doak, R.B.Koglin, J.E.Messerschmidt, M.Nass, K.Schlichting, I.Seibert, M.M.Shoeman, R.L.Williams, G.J. Tags: FEL multiplexing X-ray serial femtosecond crystallography SFX nanocrystallography research papers Source Type: research

Combining THz laser excitation with resonant soft X-ray scattering at the Linac Coherent Light Source
This paper describes the development of new instrumentation at the Linac Coherent Light Source for conducting THz excitation experiments in an ultra high vacuum environment probed by soft X-ray diffraction. This consists of a cantilevered, fully motorized mirror system which can provide 600 kV cm−1 electric field strengths across the sample and an X-ray detector that can span the full Ewald sphere with in-vacuum motion. The scientific applications motivated by this development, the details of the instrument, and spectra demonstrating the field strengths achieved using this newly developed system are discussed. (S...
Source: Journal of Synchrotron Radiation - April 11, 2015 Category: Physics Authors: Turner, J.J.Dakovski, G.L.Hoffmann, M.C.Hwang, H.Y.Zarem, A.Schlotter, W.F.Moeller, S.Minitti, M.P.Staub, U.Johnson, S.Mitra, A.Swiggers, M.Noonan, P.Curiel, G.I.Holmes, M. Tags: FEL X-ray diffraction THz instrumentation research papers Source Type: research

Nuclear resonant inelastic X-ray scattering at high pressure and low temperature
In this report, a pnictide sample, EuFe2As2, is used as an example to demonstrate this new capability at beamline 3-ID of the Advanced Photon Source, Argonne National Laboratory. A detailed description of the technical development is given. The Fe-specific phonon density of states and magnetism from the Fe sublattice in Eu57Fe2As2 at high pressure and low temperature were derived by using this new capability. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 10, 2015 Category: Physics Authors: Bi, W.Zhao, J.Lin, J.-F.Jia, Q.Hu, M.Y.Jin, C.Ferry, R.Yang, W.Struzhkin, V.Alp, E.E. Tags: nuclear resonant scattering phonon density of states high pressure low temperature iron-pnictides research papers Source Type: research

Concept of a multichannel spin-resolving electron analyzer based on Mott scattering
The concept of a multichannel electron spin detector based on optical imaging principles and Mott scattering (iMott) is presented. A multichannel electron image produced by a standard angle-resolving (photo) electron analyzer or microscope is re-imaged by an electrostatic lens at an accelerating voltage of 40 kV onto the Au target. Quasi-elastic electrons bearing spin asymmetry of the Mott scattering are imaged by magnetic lenses onto position-sensitive electron CCDs whose differential signals yield the multichannel spin asymmetry image. Fundamental advantages of this concept include acceptance of inherently divergent el...
Source: Journal of Synchrotron Radiation - April 10, 2015 Category: Physics Authors: Strocov, V.N.Petrov, V.N.Dil, J.H. Tags: electron spin Mott scattering electron optics angle-resolved photoelectron spectroscopy and microscopy X-ray free-electron lasers research papers Source Type: research

Demonstration of simultaneous experiments using thin crystal multiplexing at the Linac Coherent Light Source
In this report, the structure determination of a prototypical protein was performed using serial femtosecond crystallography simultaneously with a femtosecond time-resolved XANES studies of photoexcited spin transition dynamics in an iron spin-crossover system. The results of both experiments using the multiplexed beams are similar to those obtained separately, using a dedicated beam, with no significant differences in quality. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 10, 2015 Category: Physics Authors: Feng, Y.Alonso-Mori, R.Barends, T.R.M.Blank, V.D.Botha, S.Chollet, M.Damiani, D.S.Doak, R.B.Glownia, J.M.Koglin, J.M.Lemke, H.T.Messerschmidt, M.Nass, K.Nelson, S.Schlichting, I.Shoeman, R.L.Shvyd'ko, Y.V.Sikorski, M.Song, S.Stoupin, S.Terentyev, S.Willia Tags: FEL X-ray multiplexing diamond thin-crystal research papers Source Type: research

XAFCA: a new XAFS beamline for catalysis research
A new X-ray absorption fine-structure (XAFS) spectroscopy beamline for fundamental and applied catalysis research, called XAFCA, has been built by the Institute of Chemical and Engineering Sciences, and the Singapore Synchrotron Light Source. XAFCA covers the photon energy range from 1.2 to 12.8 keV, making use of two sets of monochromator crystals, an Si (111) crystal for the range from 2.1 to 12.8 keV and a KTiOPO4 crystal [KTP (011)] for the range between 1.2 and 2.8 keV. Experiments can be carried out in the temperature range from 4.2 to 1000 K and pressures up to 30 bar for catalysis research. A safety syste...
Source: Journal of Synchrotron Radiation - April 9, 2015 Category: Physics Authors: Du, Y.Zhu, Y.Xi, S.Yang, P.Moser, H.O.Breese, M.B.H.Borgna, A. Tags: XAFS beamline catalysis research beamlines Source Type: research

Highly porous nanoberyllium for X-ray beam speckle suppression
This paper reports a special device called a `speckle suppressor', which contains a highly porous nanoberyllium plate squeezed between two beryllium windows. The insertion of the speckle suppressor in an X-ray beam allows manipulation of the spatial coherence length, thus changing the effective source size and removing the undesirable speckle structure in X-ray imaging experiments almost without beam attenuation. The absorption of the nanoberyllium plate is below 1% for 1 mm thickness at 12 keV. The speckle suppressor was tested on the ID06 ESRF beamline with X-rays in the energy range from 9 to 15 keV. It was applie...
Source: Journal of Synchrotron Radiation - April 9, 2015 Category: Physics Authors: Goikhman, A.Lyatun, I.Ershov, P.Snigireva, I.Wojda, P.Gorlevsky, V.Semenov, A.Sheverdyaev, M.Koletskiy, V.Snigirev, A. Tags: porous nanoberyllium X-ray speckle X-ray imaging X-ray microscopy research papers Source Type: research

The In situ growth of Nanostructures on Surfaces (INS) endstation of the ESRF BM32 beamline: a combined UHV–CVD and MBE reactor for in situ X-ray scattering investigations of growing nanoparticles and semiconductor nanowires
This paper presents the upgraded `In situ growth of Nanoscructures on Surfaces' (INS) endstation of the InterFace beamline IF-BM32 at the European Synchrotron Radiation Facility (ESRF). This instrument, originally designed to investigate the structure of clean surfaces/interfaces/thin-films by surface X-ray diffraction, has been further developed to investigate the formation and evolution of nanostructures by combining small- and wide-angle X-ray scattering methodologies, i.e. grazing-incidence small-angle X-ray scattering (GISAXS) and grazing-incidence X-ray diffraction (GIXD). It consists of a UHV chamber mounted on a z-...
Source: Journal of Synchrotron Radiation - April 9, 2015 Category: Physics Authors: Cantelli, V.Geaymond, O.Ulrich, O.Zhou, T.Blanc, N.Renaud, G. Tags: in situ nanowires UHV – CVD IF-BM32 GIRD GISAXS research papers Source Type: research

Bunch mode specific rate corrections for PILATUS3 detectors
This article reports on the characterization of the new PILATUS3 detector generation at high count rates. As for all counting detectors, the measured intensities have to be corrected for the dead-time of the counting mechanism at high photon fluxes. The large number of different bunch modes at these synchrotrons as well as the wide range of detector settings presents a challenge for providing accurate corrections. To avoid the intricate measurement of the count rate behaviour for every bunch mode, a Monte Carlo simulation of the counting mechanism has been implemented, which is able to predict the corrections for arbitrary...
Source: Journal of Synchrotron Radiation - April 9, 2015 Category: Physics Authors: Trueb, P.Dejoie, C.Kobas, M.Pattison, P.Peake, D.J.Radicci, V.Sobott, B.A.Walko, D.A.Broennimann, C. Tags: PILATUS detectors photon counting count rate correction Monte Carlo simulation research papers Source Type: research

XAS and XMCD studies of magnetic properties modifications of Pt/Co/Au and Pt/Co/Pt trilayers induced by Ga+ ions irradiation
Magnetic and magneto-optical properties of Pt/Co/Au and Pt/Co/Pt trilayers subjected to 30 keV Ga+ ion irradiation are compared. In two-dimensional maps of these properties as a function of cobalt thickness and ion fluence, two branches with perpendicular magnetic anisotropy (PMA) for Pt/Co/Pt trilayers are well distinguished. The replacement of the Pt capping layer with Au results in the two branches still being visible but the in-plane anisotropy for the low-fluence branch is suppressed whereas the high-fluence branch displays PMA. The X-ray absorption spectra and X-ray magnetic circular dichroism (XMCD) spectra are di...
Source: Journal of Synchrotron Radiation - April 9, 2015 Category: Physics Authors: Mazalski, P.Sveklo, I.Kurant, Z.Ollefs, K.Rogalev, A.Wilhelm, F.Fassbender, J.Baczewski, L.T.Wawro, A.Maziewski, A. Tags: magnetic and magneto-optical properties trilayer X-ray magnetic circular dichroism (XMCD) spectra perpendicular magnetic anisotropy research papers Source Type: research

The ALBA spectroscopic LEEM-PEEM experimental station: layout and performance
The spectroscopic LEEM-PEEM experimental station at the CIRCE helical undulator beamline, which started user operation at the ALBA Synchrotron Light Facility in 2012, is presented. This station, based on an Elmitec LEEM III microscope with electron imaging energy analyzer, permits surfaces to be imaged with chemical, structural and magnetic sensitivity down to a lateral spatial resolution better than 20 nm with X-ray excited photoelectrons and 10 nm in LEEM and UV-PEEM modes. Rotation around the surface normal and application of electric and (weak) magnetic fields are possible in the microscope chamber. In situ surface...
Source: Journal of Synchrotron Radiation - April 9, 2015 Category: Physics Authors: Aballe, L.Foerster, M.Pellegrin, E.Nicolas, J.Ferrer, S. Tags: spectromicroscopy X-ray absorption photoemission LEEM PEEM X-ray magnetic dichroism research papers Source Type: research

I12: the Joint Engineering, Environment and Processing (JEEP) beamline at Diamond Light Source
I12 is the Joint Engineering, Environmental and Processing (JEEP) beamline, constructed during Phase II of the Diamond Light Source. I12 is located on a short (5 m) straight section of the Diamond storage ring and uses a 4.2 T superconducting wiggler to provide polychromatic and monochromatic X-rays in the energy range 50–150 keV. The beam energy enables good penetration through large or dense samples, combined with a large beam size (1 mrad horizontally × 0.3 mrad vertically). The beam characteristics permit the study of materials and processes inside environmental chambers without unacceptable atten...
Source: Journal of Synchrotron Radiation - April 8, 2015 Category: Physics Authors: Drakopoulos, M.Connolley, T.Reinhard, C.Atwood, R.Magdysyuk, O.Vo, N.Hart, M.Connor, L.Humphreys, B.Howell, G.Davies, S.Hill, T.Wilkin, G.Pedersen, U.Foster, A.De Maio, N.Basham, M.Yuan, F.Wanelik, K. Tags: high-energy X-rays tomography diffraction SAXS time-resolved studies beamlines Source Type: research

A dispenser–reactor apparatus applied for in situ XAS monitoring of Pt nanoparticle formation
In situ time-resolved X-ray absorption spectroscopy (XAS) measurements collected at the Pt L3-edge during the synthesis of Pt nanoparticles (NPs) in aqueous solution are reported. A specially designed dispenser–reactor apparatus allowed for monitoring changes in the XAS spectra from the earliest moments of Pt ions in solution until the formation of metallic nanoparticles with a mean diameter of 4.9 ± 1.1 nm. By monitoring the changes in the local chemical environment of the Pt atoms in real time, it was possible to observe that the NPs formation kinetics involved two stages: a reduction-nucleation burst foll...
Source: Journal of Synchrotron Radiation - April 8, 2015 Category: Physics Authors: Boita, J.Vinicius Castegnaro, M.Martins Alves, M.C.Morais, J. Tags: instrumentation in situ XAS DXAS platinum nanoparticles synthesis research papers Source Type: research

A novel crystal-analyzer phase retrieval algorithm and its noise property
A description of the rocking curve in diffraction enhanced imaging (DEI) is presented in terms of the angular signal response function and a simple multi-information retrieval algorithm based on the cosine function fitting. A comprehensive analysis of noise properties of DEI is also given considering the noise transfer characteristic of the X-ray source. The validation has been performed with synchrotron radiation experimental data and Monte Carlo simulations based on the Geant4 toolkit combined with the refractive process of X-rays, which show good agreement with each other. Moreover, results indicate that the signal-to-n...
Source: Journal of Synchrotron Radiation - April 8, 2015 Category: Physics Authors: Bao, Y.Wang, Y.Li, P.Wu, Z.Shao, Q.Gao, K.Wang, Z.Ju, Z.Zhang, K.Yuan, Q.Huang, W.Zhu, P.Wu, Z. Tags: diffraction enhanced imaging phase retrieval noise in imaging systems research papers Source Type: research

Performance optimization of a bendable parabolic cylinder collimating X-ray mirror for the ALS micro-XAS beamline 10.3.2
The Advanced Light Source (ALS) beamline (BL) 10.3.2 is an apparatus for X-ray microprobe spectroscopy and diffraction experiments, operating in the energy range 2.4–17 keV. The performance of the beamline, namely the spatial and energy resolutions of the measurements, depends significantly on the collimation quality of light incident on the monochromator. In the BL 10.3.2 end-station, the synchrotron source is imaged 1:1 onto a set of roll slits which form a virtual source. The light from this source is collimated in the vertical direction by a bendable parabolic cylinder mirror. Details are presented of the mirro...
Source: Journal of Synchrotron Radiation - April 8, 2015 Category: Physics Authors: Yashchuk, V.V.Morrison, G.Y.Marcus, M.A.Domning, E.E.Merthe, D.J.Salmassi, F.Smith, B.V. Tags: X-ray mirrors bendable mirrors at-wavelength metrology optimal surface shaping research papers Source Type: research

EIS: the scattering beamline at FERMI
The Elastic and Inelastic Scattering (EIS) beamline at the free-electron laser FERMI is presented. It consists of two separate end-stations: EIS-TIMEX, dedicated to ultrafast time-resolved studies of matter under extreme and metastable conditions, and EIS-TIMER, dedicated to time-resolved spectroscopy of mesoscopic dynamics in condensed matter. The scientific objectives are discussed and the instrument layout illustrated, together with the results from first exemplifying experiments. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 8, 2015 Category: Physics Authors: Masciovecchio, C.Battistoni, A.Giangrisostomi, E.Bencivenga, F.Principi, E.Mincigrucci, R.Cucini, R.Gessini, A.D'Amico, F.Borghes, R.Prica, M.Chenda, V.Scarcia, M.Gaio, G.Kurdi, G.Demidovich, A.Danailov, M.B.Di Cicco, A.Filipponi, A.Gunnella, R.Hatada, K. Tags: ultrafast dynamics warm dense matter four-wave mixing beamlines Source Type: research

Synchrotron radiation Mössbauer spectra of a rotating absorber with implications for testing velocity and acceleration time dilation
Many Mössbauer spectroscopy (MS) experiments have used a rotating absorber in order to measure the second-order transverse Doppler (TD) shift, and to test the validity of the Einstein time dilation theory. From these experiments, one may also test the clock hypothesis (CH) and the time dilation caused by acceleration. In such experiments the absorption curves must be obtained, since it cannot be assumed that there is no broadening of the curve during the rotation. For technical reasons, it is very complicated to keep the balance of a fast rotating disk if there are moving parts on it. Thus, the Mössbauer source o...
Source: Journal of Synchrotron Radiation - April 3, 2015 Category: Physics Authors: Friedman, Y.Yudkin, E.Nowik, I.Felner, I.Wille, H.-C.Röhlsberger, R.Haber, J.Wortmann, G.Arogeti, S.Friedman, M.Brand, Z.Levi, N.Shafir, I.Efrati, O.Frumson, T.Finkelstein, A.Chumakov, A.I.Kantor, I.Rüffer, R. Tags: M ö ssbauer effect time dilation research papers Source Type: research

Characterization of a Pt mirror to be used to deflect synchrotron radiation beam onto Langmuir monolayers
A homemade mirror for X-rays has been built to prepare a diffraction beamline for liquid surface diffraction and scattering measurements. This simple approach is in operation at the XRD2 bending-magnet beamline at the Brazilian Synchrotron Light Laboratory. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 2, 2015 Category: Physics Authors: Vieira, C.E.P.Gasperini, A.A.M.Freitas, P.P.S.Oliveira, R.G.Cavalcanti, L.P. Tags: Langmuir monolayer diffraction grazing incidence deflector mirror laboratory notes Source Type: research

Data Analysis WorkbeNch (DAWN)
Synchrotron light source facilities worldwide generate terabytes of data in numerous incompatible data formats from a wide range of experiment types. The Data Analysis WorkbeNch (DAWN) was developed to address the challenge of providing a single visualization and analysis platform for data from any synchrotron experiment (including single-crystal and powder diffraction, tomography and spectroscopy), whilst also being sufficiently extensible for new specific use case analysis environments to be incorporated (e.g. ARPES, PEEM). In this work, the history and current state of DAWN are presented, with two case studies to demons...
Source: Journal of Synchrotron Radiation - April 2, 2015 Category: Physics Authors: Basham, M.Filik, J.Wharmby, M.T.Chang, P.C.Y.El Kassaby, B.Gerring, M.Aishima, J.Levik, K.Pulford, B.C.A.Sikharulidze, I.Sneddon, D.Webber, M.Dhesi, S.S.Maccherozzi, F.Svensson, O.Brockhauser, S.Náray, G.Ashton, A.W. Tags: software DAWN visualisation analysis computer programs Source Type: research

Direct-write X-ray lithography using a hard X-ray Fresnel zone plate
Results are reported of direct-write X-ray lithography using a hard X-ray beam focused by a Fresnel zone plate with an outermost zone width of 40 nm. An X-ray beam at 7.5 keV focused to a nano-spot was employed to write arbitrary patterns on a photoresist thin film with a resolution better than 25 nm. The resulting pattern dimension depended significantly on the kind of underlying substrate, which was attributed to the lateral spread of electrons generated during X-ray irradiation. The proximity effect originated from the diffuse scattering near the focus and electron blur was also observed, which led to an increase ...
Source: Journal of Synchrotron Radiation - April 2, 2015 Category: Physics Authors: Lee, S.Y.Noh, D.Y.Lee, H.C.Yu, C.-J.Hwu, Y.Kang, H.C. Tags: direct-write X-ray lithography X-ray writer Fresnel zone plate proximity effect backscattered electrons research papers Source Type: research

X-rays only when you want them: optimized pump–probe experiments using pseudo-single-bunch operation
Laser pump–X-ray probe experiments require control over the X-ray pulse pattern and timing. Here, the first use of pseudo-single-bunch mode at the Advanced Light Source in picosecond time-resolved X-ray absorption experiments on solutions and solids is reported. In this mode the X-ray repetition rate is fully adjustable from single shot to 500 kHz, allowing it to be matched to typical laser excitation pulse rates. Suppressing undesired X-ray pulses considerably reduces detector noise and improves signal to noise in time-resolved experiments. In addition, dose-induced sample damage is considerably reduced, easing ex...
Source: Journal of Synchrotron Radiation - April 2, 2015 Category: Physics Authors: Hertlein, M.P.Scholl, A.Cordones, A.A.Lee, J.H.Engelhorn, K.Glover, T.E.Barbrel, B.Sun, C.Steier, C.Portmann, G.Robin, D.S. Tags: pump – probe spectroscopy bunch kicking pseudo single bunch X-ray pulse picking time-resolved X-ray spectroscopy sample damage laser/X-ray measurements X-ray streak camera research papers Source Type: research

General method for automatic on-line beamline optimization based on genetic algorithm
It is essential but inconvenient to perform high-quality on-line optimization for synchrotron radiation beamlines. Usually, synchrotron radiation beamlines are optimized manually, which is time-consuming and difficult to obtain global optimization for all optical elements of the beamline. In this contribution a general method based on the genetic algorithm for automatic beamline optimization is introduced. This method can optimize all optical components of any beamline simultaneously and efficiently. To test this method, a program developed using LabVIEW is examined at the XAFCA beamline of the Singapore Synchrotron Light ...
Source: Journal of Synchrotron Radiation - April 2, 2015 Category: Physics Authors: Xi, S.Borgna, L.S.Du, Y. Tags: beamline optimization genetic algorithm research papers Source Type: research

The Soft X-ray Research instrument at the Linac Coherent Light Source
The Soft X-ray Research instrument provides intense ultrashort X-ray pulses in the energy range 280–2000 eV. A diverse set of experimental stations may be installed to investigate a broad range of scientific topics such as ultrafast chemistry, highly correlated materials, magnetism, surface science, and matter under extreme conditions. A brief description of the main instrument components will be given, followed by some selected scientific highlights. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - April 2, 2015 Category: Physics Authors: Dakovski, G.L.Heimann, P.Holmes, M.Krupin, O.Minitti, M.P.Mitra, A.Moeller, S.Rowen, M.Schlotter, W.F.Turner, J.J. Tags: FEL X-ray ultrafast spectroscopy materials science beamlines Source Type: research

Radiation damage to macromolecules: kill or cure?
Radiation damage induced by X-ray beams during macromolecular diffraction experiments remains an issue of concern in structural biology. While advances in our understanding of this phenomenon, driven in part by a series of workshops in this area, undoubtedly have been and are still being made, there are still questions to be answered. Eight papers in this volume give a flavour of ongoing investigations, addressing various issues. These range over: a proposed new metric derived from atomic B-factors for identifying potentially damaged amino acid residues, a study of the relative damage susceptibility of protein and DNA in a...
Source: Journal of Synchrotron Radiation - March 1, 2015 Category: Physics Authors: Garman, E.F.Weik, M. Tags: X-ray radiation damage macromolecular crystallography FEL SAXS   damage induced phasing simulations research papers Source Type: research

Coherent imaging at the diffraction limit. Erratum
A correction to the article by Thibault et al. [J. Synchrotron Rad. (2014), 21, 1011–1018] is given. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 27, 2015 Category: Physics Authors: Thibault, P.Guizar-Sicairos, M.Menzel, A. Tags: addenda and errata Source Type: research

Current events
(Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 25, 2015 Category: Physics Authors: , Tags: current events Source Type: research

Identification of the iron oxidation state and coordination geometry in iron oxide- and zeolite-based catalysts using pre-edge XAS analysis
In conclusion, the variogram-based analysis of Fe K-edge spectra proves to be very useful in catalysis research. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 25, 2015 Category: Physics Authors: Boubnov, A.Lichtenberg, H.Mangold, S.Grunwaldt, J.-D. Tags: X-ray absorption spectroscopy pre-edge peak iron oxidation state iron coordination geometry heterogeneous iron catalysts data quality spectral resolution research papers Source Type: research

Simulations of radiation damage as a function of the temporal pulse profile in femtosecond X-ray protein crystallography
Serial femtosecond X-ray crystallography of protein nanocrystals using ultrashort and intense pulses from an X-ray free-electron laser has proved to be a successful method for structural determination. However, due to significant variations in diffraction pattern quality from pulse to pulse only a fraction of the collected frames can be used. Experimentally, the X-ray temporal pulse profile is not known and can vary with every shot. This simulation study describes how the pulse shape affects the damage dynamics, which ultimately affects the biological interpretation of electron density. The instantaneously detected signal ...
Source: Journal of Synchrotron Radiation - February 25, 2015 Category: Physics Authors: Jönsson, H.O.Tîmneanu, N.Östlin, C.Scott, H.A.Caleman, C. Tags: X-ray free-electron laser serial femtosecond crystallography radiation damage plasma simulations research papers Source Type: research

Strategies and limitations for fluorescence detection of XAFS at high flux beamlines
The issue of detecting the XAFS signal from dilute samples is discussed in detail with the aim of making best use of high flux beamlines that provide up to 1013 photons s−1. Various detection methods are compared, including filters with slits, solid state detectors, crystal analyzers and combinations of these. These comparisons rely on simulations that use experimentally determined parameters. It is found that inelastic scattering places a fundamental limit on detection, and that it is important to take proper account of the polarization dependence of the signals. The combination of a filter–slit system wit...
Source: Journal of Synchrotron Radiation - February 17, 2015 Category: Physics Authors: Heald, S.M. Tags: XAFS detectors fluorescence detection strategies research papers Source Type: research

Indications of radiation damage in ferredoxin microcrystals using high-intensity X-FEL beams
Proteins that contain metal cofactors are expected to be highly radiation sensitive since the degree of X-ray absorption correlates with the presence of high-atomic-number elements and X-ray energy. To explore the effects of local damage in serial femtosecond crystallography (SFX), Clostridium ferredoxin was used as a model system. The protein contains two [4Fe–4S] clusters that serve as sensitive probes for radiation-induced electronic and structural changes. High-dose room-temperature SFX datasets were collected at the Linac Coherent Light Source of ferredoxin microcrystals. Difference electron density maps calcula...
Source: Journal of Synchrotron Radiation - February 17, 2015 Category: Physics Authors: Nass, K.Foucar, L.Barends, T.R.M.Hartmann, E.Botha, S.Shoeman, R.L.Doak, R.B.Alonso-Mori, R.Aquila, A.Bajt, S.Barty, A.Bean, R.Beyerlein, K.R.Bublitz, M.Drachmann, N.Gregersen, J.Jönsson, H.O.Kabsch, W.Kassemeyer, S.Koglin, J.E.Krumrey, M.Mattle, D.Messe Tags: free-electron laser SFX serial femtosecond crystallography radiation damage protein crystallography metalloprotein research papers Source Type: research

Validation of a Geant4 model of the X-ray fluorescence microprobe at the Australian Synchrotron
A Geant4 Monte Carlo simulation of the X-ray fluorescence microprobe (XFM) end-station at the Australian Synchrotron has been developed. The simulation is required for optimization of the scan configuration and reconstruction algorithms. As part of the simulation process, a Gaussian beam model was developed. Experimental validation of this simulation has tested the efficacy for use of the low-energy physics models in Geant4 for this synchrotron-based technique. The observed spectral distributions calculated in the 384 pixel Maia detector, positioned in the standard back-scatter configuration, were compared with those obtai...
Source: Journal of Synchrotron Radiation - February 14, 2015 Category: Physics Authors: Dimmock, M.R.de Jonge, M.D.Howard, D.L.James, S.A.Kirkham, R.Paganin, D.M.Paterson, D.J.Ruben, G.Ryan, C.G.Brown, J.M.C. Tags: X-ray fluorescence Gaussian beam Monte Carlo simulation Geant4 Maia research papers Source Type: research

57Fe polarization-dependent synchrotron Mössbauer spectroscopy using a diamond phase plate and an iron borate nuclear Bragg monochromator
Energy-domain 57Fe polarization-dependent synchrotron radiation Mössbauer spectroscopy was developed by using a diamond X-ray phase plate and an iron borate nuclear Bragg monochromator. The former controls the polarization of the incident synchrotron radiation X-rays and the latter filters the 57Fe-Mössbauer radiation with a narrow bandwidth of ∼3.4 Γ0 (Γ0 ≃ 4.7 neV: natural linewidth of the 57Fe nucleus) from the broadband synchrotron radiation. The developed nuclear diffraction optics allowed 57Fe-Mössbauer studies to be performed with various polarization states, i.e. linear polarizati...
Source: Journal of Synchrotron Radiation - February 14, 2015 Category: Physics Authors: Mitsui, T.Imai, Y.Masuda, R.Seto, M.Mibu, K. Tags: M ö ssbauer spectroscopy diamond phase plate nuclear Bragg reflection   monochromator polarization analysis circular dichroism grazing incidence research papers Source Type: research

Identifying and quantifying radiation damage at the atomic level
Radiation damage impedes macromolecular diffraction experiments. Alongside the well known effects of global radiation damage, site-specific radiation damage affects data quality and the veracity of biological conclusions on protein mechanism and function. Site-specific radiation damage follows a relatively predetermined pattern, in that different structural motifs are affected at different dose regimes: in metal-free proteins, disulfide bonds tend to break first followed by the decarboxylation of aspartic and glutamic acids. Even within these damage motifs the decay does not progress uniformly at equal rates. Within the sa...
Source: Journal of Synchrotron Radiation - February 14, 2015 Category: Physics Authors: Gerstel, M.Deane, C.M.Garman, E.F. Tags: radiation damage specific damage preferential damage atomic B factors atomic displacement parameters research papers Source Type: research

Comparative study of the X-ray reflectivity and in-depth profile of a-C, B4C and Ni coatings at 0.1–2 keV
The use of soft X-rays near the carbon edge of absorption (270–300 eV) greatly enhances studies in various branches of science. However, the choice of reflecting coatings for mirrors operating in free-electron and X-ray free-electron laser (FEL and XFEL) beamlines in this spectral range is not so evident and experimental justifications of the mirror efficiency are rather limited. In the present paper it is demonstrated experimentally that the reflectivity of B4C- and Ni-coated grazing-incidence mirrors is high enough for their operation in FEL or XFEL beamlines near the carbon K-edge of absorption. The minimal refl...
Source: Journal of Synchrotron Radiation - February 11, 2015 Category: Physics Authors: Kozhevnikov, I.V.Filatova, E.O.Sokolov, A.A.Konashuk, A.S.Siewert, F.Störmer, M.Gaudin, J.Keitel, B.Samoylova, L.Sinn, H. Tags: soft X-ray optics XFEL mirrors inverse problem in-depth profile research papers Source Type: research

On radiation damage in FIB-prepared softwood samples measured by scanning X-ray diffraction
The high flux density encountered in scanning X-ray nanodiffraction experiments can lead to severe radiation damage to biological samples. However, this technique is a suitable tool for investigating samples to high spatial resolution. The layered cell wall structure of softwood tracheids is an interesting system which has been extensively studied using this method. The tracheid cell has a complex geometry, which requires the sample to be prepared by cutting it perpendicularly to the cell wall axis. Focused ion beam (FIB) milling in combination with scanning electron microscopy allows precise alignment and cutting without ...
Source: Journal of Synchrotron Radiation - February 11, 2015 Category: Physics Authors: Storm, S.Ogurreck, M.Laipple, D.Krywka, C.Burghammer, M.Di Cola, E.Müller, M. Tags: FIB radiation damage scanning X-ray diffraction nanodiffraction research papers Source Type: research

Towards RIP using free-electron laser SFX data
Here, it is shown that simulated native serial femtosecond crystallography (SFX) cathepsin B data can be phased by rapid ionization of sulfur atoms. Utilizing standard software adopted for radiation-damage-induced phasing (RIP), the effects on both substructure determination and phasing of the number of collected patterns and fluences are explored for experimental conditions already available at current free-electron laser facilities. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 5, 2015 Category: Physics Authors: Galli, L.Son, S.-K.White, T.A.Santra, R.Chapman, H.N.Nanao, M.H. Tags: X-ray FEL phasing radiation damage SFX research papers Source Type: research

A small and robust active beamstop for scattering experiments on high-brilliance undulator beamlines
A small active in-vacuum beamstop has been developed to monitor the flux of intense third-generation synchrotron X-ray beams protecting the downstream detector from the direct beam. Standard active beamstops, where a built-in diode directly absorbs the beam, have limitations in size and lifetime. In the present design, a silicon PIN diode detects the photons back-scattered from a cavity in the beamstop. This approach drastically reduces the radiation dose on the diode and thus increases its lifetime. The beamstop with a diameter of 2 mm has been fabricated to meet the requirements for the P12 bioSAXS beamline of EMBL Ham...
Source: Journal of Synchrotron Radiation - February 4, 2015 Category: Physics Authors: Blanchet, C.E.Hermes, C.Svergun, D.I.Fiedler, S. Tags: back-scattering radiation resistance SAXS small footprint silicon PIN diode short communications Source Type: research

Profile etching for prefiguring X-ray mirrors
A method to pre-shape mirror substrates through etching with a broad-beam ion source and a contoured mask is presented. A 100 mm-long elliptical cylinder substrate was obtained from a super-polished flat Si substrate with a 48 nm root-mean-square (r.m.s.) figure error and a 1.5 Å r.m.s. roughness after one profile-etching process at a beam voltage of 600 V without iteration. A follow-up profile coating can be used to achieve a final mirror. Profile etching and profile coating combined provide an economic way to make X-ray optics, such as nested Kirkpatrick–Baez mirrors. (Source: Journal of Synchrotron Radiation)
Source: Journal of Synchrotron Radiation - February 4, 2015 Category: Physics Authors: Liu, C.Qian, J.Assoufid, L. Tags: broad-beam ion figuring ion etching profile coating nested KB mirrors short communications Source Type: research

The influence of metallic brazing materials on the strain formation of internally water-cooled X-ray optics
A study of metallic brazing material for internally cooled optics is presented. The study shows the influence of the different material properties on the final quality of the bond in terms of diffracted wavefront distortion, i.e. enlargement of the rocking curve. By choosing the proper brazing material and applying the proper brazing conditions, the influence of the brazing material can be fully eliminated. Furthermore the degradation of some brazing material due to the extreme working conditions of the optics is presented. Measurement results from ESRF and KEK confirm the importance of the proper brazing material choice. ...
Source: Journal of Synchrotron Radiation - February 4, 2015 Category: Physics Authors: Oberta, P.Kittler, M.Áč, V.Hrdý, J.Iragashi, N.Scheinost, A.C.Uchida, Y. Tags: X-ray optics high heat load internal cooling crystal brazing research papers Source Type: research

Registration of the rotation axis in X-ray tomography
There is high demand for efficient, robust and automated routines for tomographic data reduction, particularly for synchrotron data. Registration of the rotation axis in data processing is a critical step affecting the quality of the reconstruction and is not easily implemented with automation. Existing methods for calculating the center of rotation have been reviewed and an improved algorithm to register the rotation axis in tomographic data is presented. The performance of the proposed method is evaluated using synchrotron-based microtomography data on geological samples with and without artificial reduction of the signa...
Source: Journal of Synchrotron Radiation - February 4, 2015 Category: Physics Authors: Yang, Y.Yang, F.Hingerl, F.F.Xiao, X.Liu, Y.Wu, Z.Benson, S.M.Toney, M.F.Andrews, J.C.Pianetta, P. Tags: X-ray tomography rotation axis research papers Source Type: research

Limiting radiation damage for high-brilliance biological solution scattering: practical experience at the EMBL P12 beamline PETRAIII
Radiation damage is the general curse of structural biologists who use synchrotron small-angle X-ray scattering (SAXS) to investigate biological macromolecules in solution. The EMBL-P12 biological SAXS beamline located at the PETRAIII storage ring (DESY, Hamburg, Germany) caters to an extensive user community who integrate SAXS into their diverse structural biology programs. The high brilliance of the beamline [5.1 × 1012 photons s−1, 10 keV, 500 (H) µm × 250 (V) µm beam size at the sample position], combined with automated sample handling and data acquisition protocols, enable the h...
Source: Journal of Synchrotron Radiation - February 4, 2015 Category: Physics Authors: Jeffries, C.M.Graewert, M.A.Svergun, D.I.Blanchet, C.E. Tags: protein radiation damage synchrotron small-angle scattering SAXS research papers Source Type: research

Planning, performing and analyzing X-ray Raman scattering experiments
A compilation of procedures for planning and performing X-ray Raman scattering (XRS) experiments and analyzing data obtained from them is presented. In particular, it is demonstrated how to predict the overall shape of the spectra, estimate detection limits for dilute samples, and how to normalize the recorded spectra to absolute units. In addition, methods for processing data from multiple-crystal XRS spectrometers with imaging capability are presented, including a super-resolution method that can be used for direct tomography using XRS spectra as the contrast. An open-source software package with these procedures impleme...
Source: Journal of Synchrotron Radiation - February 3, 2015 Category: Physics Authors: Sahle, Ch.J.Mirone, A.Niskanen, J.Inkinen, J.Krisch, M.Huotari, S. Tags: X-ray Raman scattering inelastic X-ray scattering spectroscopy direct   tomography research papers Source Type: research