http://journals.iucr.org/s/issues/2008/06/00/isscontsbdy.html Synchrotron radiation sources and their associated technologies have expanded at an extremely rapid rate during the past 20 years. Through the 1990s, many new synchrotron radiation sources have been constructed and exploited worldwide. The Journal of Synchrotron Radiation aims to provide a focus in this rapidly expanding area. The topics covered by the journal include source technology, instrumentation and techniques over all the spectral ranges relevant to synchrotron radiation research. It thus draws together the full breadth of interests and skills of the synchrotron radiation community. Contributions are invited within the general areas of instrumentation, methods and novel applications. The instrumentation topics include: synchrotron radiation sources and beamlines; optics; detectors; electronics and data acquisition; sample chambers and environment. The methods and applications topics are grouped within the following categories; diffraction; spectroscopy, imaging. en Copyright (c) 2008 International Union of Crystallography 2008-11-01 International Union of Crystallography International Union of Crystallography http://journals.iucr.org urn:issn:0909-0495 Synchrotron radiation sources and their associated technologies have expanded at an extremely rapid rate during the past 20 years. Through the 1990s, many new synchrotron radiation sources have been constructed and exploited worldwide. The Journal of Synchrotron Radiation aims to provide a focus in this rapidly expanding area. The topics covered by the journal include source technology, instrumentation and techniques over all the spectral ranges relevant to synchrotron radiation research. It thus draws together the full breadth of interests and skills of the synchrotron radiation community. Contributions are invited within the general areas of instrumentation, methods and novel applications. The instrumentation topics include: synchrotron radiation sources and beamlines; optics; detectors; electronics and data acquisition; sample chambers and environment. The methods and applications topics are grouped within the following categories; diffraction; spectroscopy, imaging. text/html Journal of Synchrotron Radiation, Volume 15, Part 6, 2008 text yearly 6 2002-01-01T00:00+00:00 6 15 2008-11-01 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation 543 urn:issn:0909-0495 med@iucr.org November 2008 2008-11-01 http://journals.iucr.org/logos/rss10s.gif http://journals.iucr.org/s/issues/2008/06/00/isscontsbdy.html Still image http://scripts.iucr.org/cgi-bin/paper?kv5051 Rocking curves of micro-channel (MC) water-cooled monochromators are broadened by stresses introduced during fabrication and under X-ray thermal load. This is a problem which will be even more serious with the rise of the fourth-generation synchrotron sources, i.e. the free-electron lasers. The X-ray optics group at the Institute of Physics at the ASCR v.v.i. in Prague is designing, testing and, with company Polovodiče a.s., fabricating novel internally water-cooled Si monochromators. Here three new micro-channel geometries are introduced which reduce rocking-curve enlargement owing to the fabrication to less than 2.5 µrad (∼0.5 arcsec). All three MC designs show less rocking-curve enlargement and smoother topographic images. The designs also show better cooling efficiencies than the classical MC design in finite-element analysis calculations. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Oberta, P. Áč, V. Hrdý, J. Lukáš, B. 2008-10-19 doi:10.1107/S0909049508027374 International Union of Crystallography Novel internally water-cooled Si monochromators are described which reduce rocking-curve enlargement owing to fabrication to less than 2.5 µrad. en monochromator internal cooling heat load Rocking curves of micro-channel (MC) water-cooled monochromators are broadened by stresses introduced during fabrication and under X-ray thermal load. This is a problem which will be even more serious with the rise of the fourth-generation synchrotron sources, i.e. the free-electron lasers. The X-ray optics group at the Institute of Physics at the ASCR v.v.i. in Prague is designing, testing and, with company Polovodiče a.s., fabricating novel internally water-cooled Si monochromators. Here three new micro-channel geometries are introduced which reduce rocking-curve enlargement owing to the fabrication to less than 2.5 µrad (∼0.5 arcsec). All three MC designs show less rocking-curve enlargement and smoother topographic images. The designs also show better cooling efficiencies than the classical MC design in finite-element analysis calculations. text/html Study of micro-channel geometries for internally cooled Si monochromators text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?kt5014 A new scattering technique in grazing-incidence X-ray diffraction geometry is described which enables three-dimensional mapping of reciprocal space by a single rocking scan of the sample. This is achieved by using a two-dimensional detector. The new set-up is discussed in terms of angular resolution and dynamic range of scattered intensity. As an example the diffuse scattering from a strained multilayer of self-assembled (In,Ga)As quantum dots grown on GaAs substrate is presented. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Schmidbauer, M. Schäfer, P. Besedin, S. Grigoriev, D. Köhler, R. Hanke, M. 2008-09-25 doi:10.1107/S0909049508023856 International Union of Crystallography A new scattering technique in grazing-incidence X-ray diffraction geometry is described which enables three-dimensional mapping of reciprocal space by a single rocking scan of the sample. en grazing-incidence X-ray diffraction three-dimensional reciprocal-space mapping multi-detection InGaAs quantum dots A new scattering technique in grazing-incidence X-ray diffraction geometry is described which enables three-dimensional mapping of reciprocal space by a single rocking scan of the sample. This is achieved by using a two-dimensional detector. The new set-up is discussed in terms of angular resolution and dynamic range of scattered intensity. As an example the diffuse scattering from a strained multilayer of self-assembled (In,Ga)As quantum dots grown on GaAs substrate is presented. text/html A novel multi-detection technique for three-dimensional reciprocal-space mapping in grazing-incidence X-ray diffraction text 6 15 2008-09-25 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?ie5022 The contrast mechanism for imaging molecular-scale features on solid surfaces is described for X-ray reflection interface microscopy (XRIM) through comparison of experimental images with model calculations and simulated measurements. Images of elementary steps show that image contrast is controlled by changes in the incident angle of the X-ray beam with respect to the sample surface. Systematic changes in the magnitude and sign of image contrast are asymmetric for angular deviations of the sample from the specular reflection condition. No changes in image contrast are observed when defocusing the condenser or objective lenses. These data are explained with model structure-factor calculations that reproduce all of the qualitative features observed in the experimental data. These results provide new insights into the image contrast mechanism, including contrast reversal as a function of incident angle, the sensitivity of image contrast to step direction (i.e. up versus down), and the ability to maximize image contrast at almost any scattering condition defined by the vertical momentum transfer, Qz. The full surface topography can then, in principle, be recovered by a series of images as a function of incident angle at fixed momentum transfer. Inclusion of relevant experimental details shows that the image contrast magnitude is controlled by the intersection of the reciprocal-space resolution function (i.e. controlled by numerical aperture of the condenser and objective lenses) and the spatially resolved interfacial structure factor of the object being imaged. Together these factors reduce the nominal contrast for a step near the specular reflection condition to a value similar to that observed experimentally. This formalism demonstrates that the XRIM images derive from limited aperture contrast, and explains how non-zero image contrast can be obtained when imaging a pure phase object corresponding to the interfacial topography. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Fenter, P. Park, C. Kohli, V. Zhang, Z. 2008-10-19 doi:10.1107/S0909049508023935 International Union of Crystallography The mechanism of image contrast in imaging molecular-scale features on solid surfaces is described for X-ray reflection interface microscopy through comparison of experimental images with model calculations and simulated measurements. en X-ray microscopy X-ray reflectivity interfacial X-ray scattering phase contrast full-field imaging surface topography structure factor pure phase object The contrast mechanism for imaging molecular-scale features on solid surfaces is described for X-ray reflection interface microscopy (XRIM) through comparison of experimental images with model calculations and simulated measurements. Images of elementary steps show that image contrast is controlled by changes in the incident angle of the X-ray beam with respect to the sample surface. Systematic changes in the magnitude and sign of image contrast are asymmetric for angular deviations of the sample from the specular reflection condition. No changes in image contrast are observed when defocusing the condenser or objective lenses. These data are explained with model structure-factor calculations that reproduce all of the qualitative features observed in the experimental data. These results provide new insights into the image contrast mechanism, including contrast reversal as a function of incident angle, the sensitivity of image contrast to step direction (i.e. up versus down), and the ability to maximize image contrast at almost any scattering condition defined by the vertical momentum transfer, Qz. The full surface topography can then, in principle, be recovered by a series of images as a function of incident angle at fixed momentum transfer. Inclusion of relevant experimental details shows that the image contrast magnitude is controlled by the intersection of the reciprocal-space resolution function (i.e. controlled by numerical aperture of the condenser and objective lenses) and the spatially resolved interfacial structure factor of the object being imaged. Together these factors reduce the nominal contrast for a step near the specular reflection condition to a value similar to that observed experimentally. This formalism demonstrates that the XRIM images derive from limited aperture contrast, and explains how non-zero image contrast can be obtained when imaging a pure phase object corresponding to the interfacial topography. text/html Image contrast in X-ray reflection interface microscopy: comparison of data with model calculations and simulations text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?hi5588 Micro X-ray absorption near-edge spectroscopy at the Mg K-edge is a useful technique for acquiring information about the environment of Mg2+ in biogenic calcite. These analyses can be applied to shell powders or intact shell structures. The advantage of the latter is that the XANES analyses can be applied to specific areas, at high (e.g. micrometre) spatial resolution, to determine the environment of Mg2+ in a biomineral context. Such in situ synchrotron analysis has to take into account the potential effect of crystallographic orientation given the anisotropy of calcite crystals and the polarized nature of X-rays. Brachiopod shells of species with different crystallographic orientations are used to assess this crystallographic effect on in situ synchrotron measurements at the Mg K-edge. Results show that, owing to the anisotropy of calcite, in situ X-ray absorption spectra (XAS) are influenced by the crystallographic orientation of calcite crystals with a subsequent potentially erroneous interpretation of Mg2+ data. Thus, this study demonstrates the importance of crystallography for XAS analyses and, therefore, the necessity to obtain crystallographic information at high spatial resolution prior to spectroscopic analysis. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Pérez-Huerta, A. Cusack, M. Janousch, M. Finch, A.A. 2008-10-19 doi:10.1107/S0909049508026484 International Union of Crystallography PLEASE SUPPLY A SHORT ONE- OR TWO-SENTENCE SYNOPSIS FOR THE TABLE OF CONTENTS en brachiopods calcite XAS crystal lattice c-axis Micro X-ray absorption near-edge spectroscopy at the Mg K-edge is a useful technique for acquiring information about the environment of Mg2+ in biogenic calcite. These analyses can be applied to shell powders or intact shell structures. The advantage of the latter is that the XANES analyses can be applied to specific areas, at high (e.g. micrometre) spatial resolution, to determine the environment of Mg2+ in a biomineral context. Such in situ synchrotron analysis has to take into account the potential effect of crystallographic orientation given the anisotropy of calcite crystals and the polarized nature of X-rays. Brachiopod shells of species with different crystallographic orientations are used to assess this crystallographic effect on in situ synchrotron measurements at the Mg K-edge. Results show that, owing to the anisotropy of calcite, in situ X-ray absorption spectra (XAS) are influenced by the crystallographic orientation of calcite crystals with a subsequent potentially erroneous interpretation of Mg2+ data. Thus, this study demonstrates the importance of crystallography for XAS analyses and, therefore, the necessity to obtain crystallographic information at high spatial resolution prior to spectroscopic analysis. text/html Influence of crystallographic orientation of biogenic calcite on in situ Mg XANES analyses text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?hi5589 The technique of coherent X-ray diffraction imaging (CXDI) has recently shown great promise for the study of inorganic nanocrystals. In this work the CXDI method has been applied to the study of micrometer-size protein crystals. Finely sampled diffraction patterns of single crystals were measured and iterative phase-retrieval algorithms were used to reconstruct the two-dimensional shape of the crystal. The density maps have limited reproducibility because of radiation damage, but show clear evidence for crystal facets. Qualitative analysis of a number of single-crystal diffraction peaks indicates the presence of inward surface contraction on 2 µm size crystals. A survey of several hundred diffraction patterns yielded a number of examples with dramatic single-sided streaks, for which a plausible model is constructed. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Boutet, S. Robinson, I.K. 2008-10-19 doi:10.1107/S0909049508029439 International Union of Crystallography Single crystals of the protein ferritin are imaged using coherent X-ray diffraction imaging and the results show the presence of inward surface strain. en coherent X-ray diffractive imaging protein crystals ferritin phase retrieval surface contraction The technique of coherent X-ray diffraction imaging (CXDI) has recently shown great promise for the study of inorganic nanocrystals. In this work the CXDI method has been applied to the study of micrometer-size protein crystals. Finely sampled diffraction patterns of single crystals were measured and iterative phase-retrieval algorithms were used to reconstruct the two-dimensional shape of the crystal. The density maps have limited reproducibility because of radiation damage, but show clear evidence for crystal facets. Qualitative analysis of a number of single-crystal diffraction peaks indicates the presence of inward surface contraction on 2 µm size crystals. A survey of several hundred diffraction patterns yielded a number of examples with dramatic single-sided streaks, for which a plausible model is constructed. text/html Coherent X-ray diffractive imaging of protein crystals text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?kt5015 Finite-element analysis is frequently used by engineers at synchrotron beamlines to calculate the elastic deformation of a single crystal undergoing mechanical bending or thermal load. ANSYS® Workbench™ software is widely used for such simulations. However, although ANSYS® Workbench™ software provides useful information on the displacements, strains and stresses within the crystal, it does not yield the local reciprocal lattice vectors that would be required for X-ray diffraction calculations. To bridge this gap, a method based on the shape functions and interpolation procedures of the software itself has been developed. An application to the double-crystal bent Laue monochromator being designed for the I12 (JEEP) wiggler beamline at the Diamond Light Source is presented. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Sutter, J.P. Connolley, T. Hill, T.P. Huang, H. Sharp, D.W. Drakopoulos, M. 2008-10-19 doi:10.1107/S090904950802801X International Union of Crystallography This report presents a simple procedure for extracting local reciprocal lattice vectors from the displacements calculated within a crystal under bending or thermal load by the widely used ANSYS® Workbench™ finite-element software. en finite element X-ray diffraction lattice Finite-element analysis is frequently used by engineers at synchrotron beamlines to calculate the elastic deformation of a single crystal undergoing mechanical bending or thermal load. ANSYS® Workbench™ software is widely used for such simulations. However, although ANSYS® Workbench™ software provides useful information on the displacements, strains and stresses within the crystal, it does not yield the local reciprocal lattice vectors that would be required for X-ray diffraction calculations. To bridge this gap, a method based on the shape functions and interpolation procedures of the software itself has been developed. An application to the double-crystal bent Laue monochromator being designed for the I12 (JEEP) wiggler beamline at the Diamond Light Source is presented. text/html Obtaining local reciprocal lattice vectors from finite-element analysis text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?pm5024 Atomic-resolution structures from small proteins have recently been determined from high-quality powder diffraction patterns using a combination of stereochemical restraints and Rietveld refinement [Von Dreele (2007), J. Appl. Cryst. 40, 133–143; Margiolaki et al. (2007), J. Am. Chem. Soc. 129, 11865–11871]. While powder diffraction data have been obtained from batch samples of small crystal-suspensions, which are exposed to X-rays for long periods of time and undergo significant radiation damage, the proof-of-concept that protein powder diffraction data from nanocrystals of a membrane protein can be obtained using a continuous microjet is shown. This flow-focusing aerojet has been developed to deliver a solution of hydrated protein nanocrystals to an X-ray beam for diffraction analysis. This method requires neither the crushing of larger polycrystalline samples nor any techniques to avoid radiation damage such as cryocooling. Apparatus to record protein powder diffraction in this manner has been commissioned, and in this paper the first powder diffraction patterns from a membrane protein, photosystem I, with crystallite sizes of less than 500 nm are presented. These preliminary patterns show the lowest-order reflections, which agree quantitatively with theoretical calculations of the powder profile. The results also serve to test our aerojet injector system, with future application to femtosecond diffraction in free-electron X-ray laser schemes, and for serial crystallography using a single-file beam of aligned hydrated molecules. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Shapiro, D.A. Chapman, H.N. DePonte, D. Doak, R.B. Fromme, P. Hembree, G. Hunter, M. Marchesini, S. Schmidt, K. Spence, J. Starodub, D. Weierstall, U. 2008-10-19 doi:10.1107/S0909049508024151 International Union of Crystallography Protein powder diffraction data can be obtained from submicrometer crystals of the membrane protein photosystem 1 using a flow-focusing liquid microjet for sample delivery. en serial crystallography membrane proteins protein structure radiation damage nanocrystals Atomic-resolution structures from small proteins have recently been determined from high-quality powder diffraction patterns using a combination of stereochemical restraints and Rietveld refinement [Von Dreele (2007), J. Appl. Cryst. 40, 133–143; Margiolaki et al. (2007), J. Am. Chem. Soc. 129, 11865–11871]. While powder diffraction data have been obtained from batch samples of small crystal-suspensions, which are exposed to X-rays for long periods of time and undergo significant radiation damage, the proof-of-concept that protein powder diffraction data from nanocrystals of a membrane protein can be obtained using a continuous microjet is shown. This flow-focusing aerojet has been developed to deliver a solution of hydrated protein nanocrystals to an X-ray beam for diffraction analysis. This method requires neither the crushing of larger polycrystalline samples nor any techniques to avoid radiation damage such as cryocooling. Apparatus to record protein powder diffraction in this manner has been commissioned, and in this paper the first powder diffraction patterns from a membrane protein, photosystem I, with crystallite sizes of less than 500 nm are presented. These preliminary patterns show the lowest-order reflections, which agree quantitatively with theoretical calculations of the powder profile. The results also serve to test our aerojet injector system, with future application to femtosecond diffraction in free-electron X-ray laser schemes, and for serial crystallography using a single-file beam of aligned hydrated molecules. text/html Powder diffraction from a continuous microjet of submicrometer protein crystals text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?bf5014 An X-ray reflectivity set-up to study buried interfaces at beamline BL9 of the electron storage ring DELTA is presented. The structure of solid–gas and solid–liquid interfaces can be investigated using X-rays with incident energies of about 27 keV. A detailed description of the set-up is given and its performance is demonstrated by a discussion of selected applications, i.e. protein adsorption at the solid–liquid interface and gas adsorption at the solid–gas interface at elevated pressures. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Paulus, M. Lietz, D. Sternemann, C. Shokuie, K. Evers, F. Tolan, M. Czeslik, C. Winter, R. 2008-10-19 doi:10.1107/S0909049508026745 International Union of Crystallography The high-energy X-ray reflectivity set-up of BL9 at DELTA is presented together with measurements which show the capabilities of the set-up. en X-ray reflectivity solid–liquid interfaces beamline An X-ray reflectivity set-up to study buried interfaces at beamline BL9 of the electron storage ring DELTA is presented. The structure of solid–gas and solid–liquid interfaces can be investigated using X-rays with incident energies of about 27 keV. A detailed description of the set-up is given and its performance is demonstrated by a discussion of selected applications, i.e. protein adsorption at the solid–liquid interface and gas adsorption at the solid–gas interface at elevated pressures. text/html An access to buried interfaces: the X-ray reflectivity set-up of BL9 at DELTA text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?pm5025 When small triangular prisms are arranged in arrays which have an overall appearance like an hourglass (in Italian: clessidra) they can focus X-rays owing to a combined action of diffraction and refraction. From the optical point of view these objects can be regarded as a Fresnel variant of concave transmission lenses. Consequently they can provide larger apertures than purely refractive lenses. However, one has to recognize that clessidra lenses will strongly diffract as the lens structure is periodic in the direction perpendicular to the incident beam. In experiments the diffraction is reduced because it is difficult to illuminate the large apertures with a full spatially coherent wavefront. So the illumination is at best partially coherent. In order to interpret available experimental data for this condition, diffraction theory has been applied appropriately to the clessidra structure, taking into account the limited spatial coherence. The agreement between the theoretical simulations and experimental data is very good, keeping the lens properties at their projected values and allowing for only two free model parameters. The first is the lateral spatial coherence; the second is a lens defect, a rounding of all edges and tips in the structure. Both values obtained from the simulations have been found to be in agreement with expectations. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 De Caro, L. Jark, W. Menk, R.H. Matteucci, M. 2008-10-19 doi:10.1107/S0909049508029762 International Union of Crystallography Diffraction of partially coherent X-ray waves from clessidra (hourglass) lenses has been theoretically described. The good agreement between theory and experimental data leads to an insight into the operation of clessidra lenses. en X-ray optics kinoform lens refraction diffraction spatial coherence When small triangular prisms are arranged in arrays which have an overall appearance like an hourglass (in Italian: clessidra) they can focus X-rays owing to a combined action of diffraction and refraction. From the optical point of view these objects can be regarded as a Fresnel variant of concave transmission lenses. Consequently they can provide larger apertures than purely refractive lenses. However, one has to recognize that clessidra lenses will strongly diffract as the lens structure is periodic in the direction perpendicular to the incident beam. In experiments the diffraction is reduced because it is difficult to illuminate the large apertures with a full spatially coherent wavefront. So the illumination is at best partially coherent. In order to interpret available experimental data for this condition, diffraction theory has been applied appropriately to the clessidra structure, taking into account the limited spatial coherence. The agreement between the theoretical simulations and experimental data is very good, keeping the lens properties at their projected values and allowing for only two free model parameters. The first is the lateral spatial coherence; the second is a lens defect, a rounding of all edges and tips in the structure. Both values obtained from the simulations have been found to be in agreement with expectations. text/html Diffraction of partially coherent X-rays in clessidra prism arrays text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?fh5387 An experimental comparison of models for performing dead-time corrections of photon-counting detectors at synchrotron sources is presented. The performance of several detectors in the three operating modes of the Advanced Photon Source is systematically compared, with particular emphasis on asymmetric fill patterns. Several simple and well known correction formulas are evaluated. The results demonstrate the critical importance of detector speed and synchrotron fill pattern in selecting the proper dead-time correction. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Walko, D.A. Arms, D.A. Landahl, E.C. 2008-09-25 doi:10.1107/S0909049508022358 International Union of Crystallography Dead-time corrections are presented for different operating modes of a synchrotron. Detector speed and synchrotron fill pattern are critical for determining appropriate dead-time corrections. en dead-time photon detector synchrotron fill pattern data correction An experimental comparison of models for performing dead-time corrections of photon-counting detectors at synchrotron sources is presented. The performance of several detectors in the three operating modes of the Advanced Photon Source is systematically compared, with particular emphasis on asymmetric fill patterns. Several simple and well known correction formulas are evaluated. The results demonstrate the critical importance of detector speed and synchrotron fill pattern in selecting the proper dead-time correction. text/html Empirical dead-time corrections for synchrotron sources text 6 15 2008-09-25 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?kv5048 Inelastic X-ray scattering (IXS) measurements have been performed on an MgO single crystal in order to evaluate IXS as a methodology for accurate and precise determination of elastic constants and sound velocities. By performing the IXS experiment using a 12-analyzer array, the complete set of single-crystal elastic constants of MgO were determined to a precision better than 0.8% (sound velocities to better than 0.2%). The results are consistent with values in the literature. The precision and accuracy of this work, which is significantly better than other published work to date, demonstrates the potential of IXS in determining elastic properties. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Fukui, H. Katsura, T. Kuribayashi, T. Matsuzaki, T. Yoneda, A. Ito, E. Kudoh, Y. Tsutsui, S. Baron, A.Q.R. 2008-09-25 doi:10.1107/S0909049508023248 International Union of Crystallography By performing inelastic X-ray scattering experiments using a 12-analyzer array, the complete set of single-crystal elastic constants of MgO were determined to a precision better than 0.8% (sound velocities to better than 0.2%). en inelastic X-ray scattering elastic constants sound velocity single crystal MgO the Christoffel equation Inelastic X-ray scattering (IXS) measurements have been performed on an MgO single crystal in order to evaluate IXS as a methodology for accurate and precise determination of elastic constants and sound velocities. By performing the IXS experiment using a 12-analyzer array, the complete set of single-crystal elastic constants of MgO were determined to a precision better than 0.8% (sound velocities to better than 0.2%). The results are consistent with values in the literature. The precision and accuracy of this work, which is significantly better than other published work to date, demonstrates the potential of IXS in determining elastic properties. text/html Precise determination of elastic constants by high-resolution inelastic X-ray scattering text 6 15 2008-09-25 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?tc5005 Inner-shell electronic structures, properties and ionization spectra of DNA/RNA bases are studied with respect to their parent pyrimidine and purine species. Density functional theory B3LYP/aug-cc-pVTZ has been employed to produce the geometries of the bases, whereas LB94/et-pVQZ//B3LYP/aug-cc-pVTZ is used to calculate site-related Hirshfeld charges and core (vertical) ionization energies, as well as inner-shell spectra of C1s, N1s and O1s for DNA/RNA bases and their parent pyrimidine and purine species. The site-dependent variations of properties indicate the changes and inheritance of chemical environment when pyrimidine and purine become substituted. In general, although the changes are site-dependent, they are also ring-dependent. Pyrimidine bases change less significantly with respect to their parent pyrimidine than the purine bases with respect to their parent purine. Pyrimidine bases such as uracil, thymine and cytosine inherit certain properties from their parent pyrimidine, such as the Hirshfeld charge distributions and the order of core ionization energy level etc. No particular sites in the pyrimidine derivatives are engaged with a dramatic chemical shift nor with energy crossings to other sites. For the core shell spectra, the purine bases inherit very little from their parent purine, and guanine exhibits the least similarities to the parent among all the DNA/RNA bases. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Wang, F. Zhu, Q. Ivanova, E. 2008-09-25 doi:10.1107/S090904950802387X International Union of Crystallography The main red shift of N1s and C1s core ionization spectra of the purine bases is found with respect to the unsubstituted purine, and is different from the dominated blue shift in the pyrimidine counterparts. The atomic-site-dependent energy-level crossings of the core ionization spectral peaks in adenine, guanine and unsubstituted purine are detailed. en pyrimidine bases purine bases inner-shell ionization spectra chemical shift property and spectral inheritance Inner-shell electronic structures, properties and ionization spectra of DNA/RNA bases are studied with respect to their parent pyrimidine and purine species. Density functional theory B3LYP/aug-cc-pVTZ has been employed to produce the geometries of the bases, whereas LB94/et-pVQZ//B3LYP/aug-cc-pVTZ is used to calculate site-related Hirshfeld charges and core (vertical) ionization energies, as well as inner-shell spectra of C1s, N1s and O1s for DNA/RNA bases and their parent pyrimidine and purine species. The site-dependent variations of properties indicate the changes and inheritance of chemical environment when pyrimidine and purine become substituted. In general, although the changes are site-dependent, they are also ring-dependent. Pyrimidine bases change less significantly with respect to their parent pyrimidine than the purine bases with respect to their parent purine. Pyrimidine bases such as uracil, thymine and cytosine inherit certain properties from their parent pyrimidine, such as the Hirshfeld charge distributions and the order of core ionization energy level etc. No particular sites in the pyrimidine derivatives are engaged with a dramatic chemical shift nor with energy crossings to other sites. For the core shell spectra, the purine bases inherit very little from their parent purine, and guanine exhibits the least similarities to the parent among all the DNA/RNA bases. text/html Inner-shell chemical shift of DNA/RNA bases and inheritance from their parent purine and pyrimidine text 6 15 2008-09-25 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?fh5379 It has previously been shown that there are many benefits to be obtained in combining several techniques in one in situ set-up to study chemical processes in action. Many of these combined set-ups make use of two techniques, but in some cases it is possible and useful to combine even more. A set-up has recently been developed that combines three X-ray-based techniques, small- and wide-angle X-ray scattering (SAXS/WAXS) and quick-scanning EXAFS (QEXAFS), for the study of dynamical chemical processes. The set-up is able to probe the same part of the sample during the synthesis process and is thus able to follow changes at the nanometre to micrometre scale during, for example, materials self-assembly, with a time resolution of the order of a few minutes. The practicality of this kind of experiment has been illustrated by studying zeotype crystallization processes and revealed important new insights into the interplay of the various stages of ZnAPO-34 formation. The flexibility of this set-up for studying other processes and for incorporating other additional non-X-ray-based experimental techniques has also been explored and demonstrated for studying the stability/activity of iron molybdate catalysts for the anaerobic decomposition of methanol. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Nikitenko, S. Beale, A.M. van der Eerden, A.M.J. Jacques, S.D.M. Leynaud, O. O'Brien, M.G. Detollenaere, D. Kaptein, R. Weckhuysen, B.M. Bras, W. 2008-09-25 doi:10.1107/S0909049508023327 International Union of Crystallography A set-up has recently been developed that combines three X-ray-based techniques, small- and wide-angle X-ray scattering (SAXS/WAXS) and quick-scanning EXAFS (QEXAFS), for the study of dynamical chemical processes. en XAFS SAXS WAXS It has previously been shown that there are many benefits to be obtained in combining several techniques in one in situ set-up to study chemical processes in action. Many of these combined set-ups make use of two techniques, but in some cases it is possible and useful to combine even more. A set-up has recently been developed that combines three X-ray-based techniques, small- and wide-angle X-ray scattering (SAXS/WAXS) and quick-scanning EXAFS (QEXAFS), for the study of dynamical chemical processes. The set-up is able to probe the same part of the sample during the synthesis process and is thus able to follow changes at the nanometre to micrometre scale during, for example, materials self-assembly, with a time resolution of the order of a few minutes. The practicality of this kind of experiment has been illustrated by studying zeotype crystallization processes and revealed important new insights into the interplay of the various stages of ZnAPO-34 formation. The flexibility of this set-up for studying other processes and for incorporating other additional non-X-ray-based experimental techniques has also been explored and demonstrated for studying the stability/activity of iron molybdate catalysts for the anaerobic decomposition of methanol. text/html Implementation of a combined SAXS/WAXS/QEXAFS set-up for time-resolved in situexperiments text 6 15 2008-09-25 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?gf5008 Radioactive 125I emits short-range Auger electrons and represents a human health risk when incorporated in thyroglobulin of the thyroid. Quantitative evaluation of this risk can only be realised if local atomic order about iodine in the thyroid is known. Here, extended X-ray absorption fine structure (EXAFS) has been used to probe the local structure about iodine in pure thyroid hormone, thyroxine. These data are consistent with a model where iodine is bound to a single iodinated carbon ring linked to an oxygen atom, similar to a previously published model for monoiodotyrosine, a major iodinated residue in thyroglobulin. Several structural models for the local environment of iodine from rat, human and sheep have been tested and these data are found to be compatible with a slightly modified environment with respect to that found for thyroxine. The best-fit models include the following three components: (i) iodine covalently bonded to a tyrosine ring, as found for thyroxine; (ii) iodine bonded quasi-covalently to a carbonyl ligand in partially filled (50%) sites; (iii) partially filled sites (50–40%) of carbonyl ligands, with oxygen at van der Waals distances from iodine. Advantages of using Fourier-filtered EXAFS for complex crystal structures are discussed. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Orton, B.R. Bilsborrow, R. 2008-10-19 doi:10.1107/S0909049508026435 International Union of Crystallography A satisfactory model was found for EXAFS from iodine in thyroxine; this model was augmented to include quasi-covalent bonding from iodine to carbonyl ligands for rat, human and sheep thyroids. These models will be helpful in estimates of radiation dose to thyroids from Auger electrons emitted by radioactive iodine. en EXAFS thyroxine thyroids Auger electrons radiation risk Radioactive 125I emits short-range Auger electrons and represents a human health risk when incorporated in thyroglobulin of the thyroid. Quantitative evaluation of this risk can only be realised if local atomic order about iodine in the thyroid is known. Here, extended X-ray absorption fine structure (EXAFS) has been used to probe the local structure about iodine in pure thyroid hormone, thyroxine. These data are consistent with a model where iodine is bound to a single iodinated carbon ring linked to an oxygen atom, similar to a previously published model for monoiodotyrosine, a major iodinated residue in thyroglobulin. Several structural models for the local environment of iodine from rat, human and sheep have been tested and these data are found to be compatible with a slightly modified environment with respect to that found for thyroxine. The best-fit models include the following three components: (i) iodine covalently bonded to a tyrosine ring, as found for thyroxine; (ii) iodine bonded quasi-covalently to a carbonyl ligand in partially filled (50%) sites; (iii) partially filled sites (50–40%) of carbonyl ligands, with oxygen at van der Waals distances from iodine. Advantages of using Fourier-filtered EXAFS for complex crystal structures are discussed. text/html EXAFS study of local atomic order about iodine in thyroxine, rat, human and sheep thyroids text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?ia5031 A micro test pattern prepared by focused ion beam milling was used to evaluate the three-dimensional resolution of a microtomograph at the BL20B2 beamline of SPring-8. The resolutions along the direction within the tomographic slice plane and perpendicular to it were determined from the modulation transfer functions. The through-plane resolution perpendicular to the tomographic slice was evaluated to be 8 µm, which corresponds to the spatial resolution of two-dimensional radiographs. In contrast, the in-plane resolution within the slice was evaluated to be 12 µm. Real-space interpolation was performed prior to the tomographic reconstruction, giving an improved in-plane resolution of 8.5 µm. However, the 8 µm pitch pattern was resolved in the interpolated slice image. To reflect this result, another resolution measure from the peak-to-valley difference plot was introduced. This resolution measure gave resolution limits of 7.4 µm for the in-plane direction and 6.1 µm for the through-plane direction. The three-dimensional test pattern along with the interpolated reconstruction enables the quantitative evaluation of the spatial resolution of microtomographs. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Mizutani, R. Takeuchi, A. Uesugi, K. Suzuki, Y. 2008-10-19 doi:10.1107/S0909049508025685 International Union of Crystallography The spatial resolution of a synchrotron radiation computed tomograph was examined using a micro-fabricated test pattern. en computed tomography micro-CT spatial resolution FIB MTF A micro test pattern prepared by focused ion beam milling was used to evaluate the three-dimensional resolution of a microtomograph at the BL20B2 beamline of SPring-8. The resolutions along the direction within the tomographic slice plane and perpendicular to it were determined from the modulation transfer functions. The through-plane resolution perpendicular to the tomographic slice was evaluated to be 8 µm, which corresponds to the spatial resolution of two-dimensional radiographs. In contrast, the in-plane resolution within the slice was evaluated to be 12 µm. Real-space interpolation was performed prior to the tomographic reconstruction, giving an improved in-plane resolution of 8.5 µm. However, the 8 µm pitch pattern was resolved in the interpolated slice image. To reflect this result, another resolution measure from the peak-to-valley difference plot was introduced. This resolution measure gave resolution limits of 7.4 µm for the in-plane direction and 6.1 µm for the through-plane direction. The three-dimensional test pattern along with the interpolated reconstruction enables the quantitative evaluation of the spatial resolution of microtomographs. text/html Evaluation of the improved three-dimensional resolution of a synchrotron radiation computed tomograph using a micro-fabricated test pattern text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?wr5009 IKNO (Innovation and KNOwledge) is a proposal for a multi-user facility based on an electron storage ring optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range, and of broadband incoherent synchrotron radiation ranging from the IR to the VUV. IKNO can be operated in an ultra-stable CSR mode with photon flux in the terahertz frequency region up to nine orders of magnitude higher than in existing third-generation light sources. Simultaneously to the CSR operation, broadband incoherent synchrotron radiation up to VUV frequencies is available at the beamline ports. The main characteristics of the IKNO storage and its performance in terms of CSR and incoherent synchrotron radiation are described in this paper. The proposed location for the infrastructure facility is Sardinia, Italy. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Sannibale, F. Marcelli, A. Innocenzi, P. 2008-09-25 doi:10.1107/S0909049508023959 International Union of Crystallography IKNO, a proposal for a multi-user synchrotron radiation source optimized for the generation of coherent synchrotron radiation in the terahertz frequency range, with many orders of magnitude higher photon flux than in existing sources, is presented. Additionally, the incoherent radiation spectrum of IKNO extends up to the VUV frequencies with flux comparable with that of a third-generation synchrotron light source. en synchrotron radiation source terahertz coherent synchrotron radiation UV IKNO (Innovation and KNOwledge) is a proposal for a multi-user facility based on an electron storage ring optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range, and of broadband incoherent synchrotron radiation ranging from the IR to the VUV. IKNO can be operated in an ultra-stable CSR mode with photon flux in the terahertz frequency region up to nine orders of magnitude higher than in existing third-generation light sources. Simultaneously to the CSR operation, broadband incoherent synchrotron radiation up to VUV frequencies is available at the beamline ports. The main characteristics of the IKNO storage and its performance in terms of CSR and incoherent synchrotron radiation are described in this paper. The proposed location for the infrastructure facility is Sardinia, Italy. text/html IKNO, a user facility for coherent terahertz and UV synchrotron radiation text 6 15 2008-09-25 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation research papers 0 0 http://scripts.iucr.org/cgi-bin/paper?wl5146 A quantitative application of microradiology with coherent X-rays to the real-time study of microbubble and microdroplet coalescence phenomena, with specific emphasis on the size relations in three-body events, is presented. The results illustrate the remarkable effectiveness of coherent X-ray imaging in delineating interfaces in multiphase systems, in accurately measuring their geometric properties and in monitoring their dynamics. Copyright (c) 2008 International Union of Crystallography urn:issn:0909-0495 Weon, B.M. Je, J.H. Hwu, Y. Margaritondo, G. 2008-10-19 doi:10.1107/S0909049508025363 International Union of Crystallography Microradiology with coherent X-rays is shown to be very effective in revealing interfaces in multiphase systems and in particular gas bubbles. Its use has been tested in the study of bubble colescence validating the results with a simple theoretical analysis based on mass conservation. en coherent synchrotron X-ray microradiology coalescence bubbles droplets A quantitative application of microradiology with coherent X-rays to the real-time study of microbubble and microdroplet coalescence phenomena, with specific emphasis on the size relations in three-body events, is presented. The results illustrate the remarkable effectiveness of coherent X-ray imaging in delineating interfaces in multiphase systems, in accurately measuring their geometric properties and in monitoring their dynamics. text/html A coherent synchrotron X-ray microradiology investigation of bubble and droplet coalescence text 6 15 2008-10-19 Copyright (c) 2008 International Union of Crystallography Journal of Synchrotron Radiation short communications 0 0