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Sample records for x-ray absorption fine

  1. Speciation of Lead in a Mixed Soil Component System Using X-ray Absorption Fine Structure Spectroscopy

    E-Print Network [OSTI]

    Sparks, Donald L.

    Speciation of Lead in a Mixed Soil Component System Using X-ray Absorption Fine Structure (XAFS). Lead concentrations of 6000, 18000, and 29000 µg Pb/g solid were reacted with soil components

  2. Temperature dependence of the Pd [ital K]-edge extended x-ray-absorption fine structure of PdC[sub [ital x

    SciTech Connect (OSTI)

    McCaulley, J.A. (Hoechst Celanese Research Division, Robert L. Mitchell Technical Center, 86 Morris Avenue, Summit, New Jersey 07901 (United States))

    1993-03-01

    Pd [ital K]-edge extended x-ray-absorption fine-structure (EXAFS) and x-ray-absorption near-edge-structure (XANES) measurements were performed on a Pd carbide phase, PdC[sub [ital x

  3. Near-Edge X-Ray Absorption Fine Structure Spectroscopy of Diamondoid Thiol Monolayers on Gold

    SciTech Connect (OSTI)

    Willey, T.M.; Fabbri, J.D.; Lee, J.R.I.; Schreiner, P.R.; Fokin, A.A.; Tkachenko, B.A.; Fokina, N.A.; Dahl, J.E.P.; Carlson, R.M.K.; Vance, A.L.; Yang, W.; Terminello, L.J.; Buuren, T.van; Melosh, N.A.

    2009-05-26

    Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibilities for surface modification, for high-efficiency field emitters in molecular electronics, as seed crystals for diamond growth, or as robust mechanical coatings. The properties of self-assembled monolayers (SAMs) of diamondoids are thus of fundamental interest for a variety of emerging applications. This paper presents the effects of thiol substitution position and polymantane order on diamondoid SAMs on gold using near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and X-ray photoelectron spectroscopy (XPS). A framework to determine both molecular tilt and twist through NEXAFS is presented and reveals highly ordered diamondoid SAMs, with the molecular orientation controlled by the thiol location. C 1s and S 2p binding energies are lower in adamantane thiol than alkane thiols on gold by 0.67 {+-} 0.05 and 0.16 {+-} 0.04 eV, respectively. These binding energies vary with diamondoid monolayer structure and thiol substitution position, consistent with different degrees of steric strain and electronic interaction with the substrate. This work demonstrates control over the assembly, in particular the orientational and electronic structure, providing a flexible design of surface properties with this exciting new class of diamond nanoparticles.

  4. Near-Edge X-ray Absorption Fine Structure Spectroscopy of Diamondoid Thiol Monolayers on Gold

    SciTech Connect (OSTI)

    Willey, T M; Fabbri, J; Lee, J I; Schreiner, P; Fokin, A A; Tkachenko, B A; Fokina, N A; Dahl, J; Carlson, B; Vance, A L; Yang, W; Terminello, L J; van Buuren, T; Melosh, N

    2007-11-27

    Diamondoids, hydrocarbon molecules with cubic-diamond-cage structures, have unique properties with potential value for nanotechnology. The availability and ability to selectively functionalize this special class of nanodiamond materials opens new possibilities for surface-modification, for high-efficiency field emitters in molecular electronics, as seed crystals for diamond growth, or as robust mechanical coatings. The properties of self-assembled monolayers (SAMs) of diamondoids are thus of fundamental interest for a variety of emerging applications. This paper presents the effects of thiol substitution position and polymantane order on diamondoid SAMs on gold using near-edge X-ray absorption fine structure spectroscopy (NEXAFS) and X-ray photoelectron spectroscopy (XPS). A framework to determine both molecular tilt and twist through NEXAFS is presented and reveals highly ordered diamondoid SAMs, with the molecular orientation controlled by the thiol location. C 1s and S 2p binding energies are lower in adamantane thiol than alkane thiols on gold by 0.67 {+-} 0.05 eV and 0.16 {+-} 0.04 eV respectively. These binding energies vary with diamondoid monolayer structure and thiol substitution position, consistent with different amounts of steric strain and electronic interaction with the substrate. This work demonstrates control over the assembly, in particular the orientational and electronic structure, providing a flexible design of surface properties with this exciting new class of diamond clusters.

  5. X-ray absorption fine structure spectroscopic study of uranium nitrides

    SciTech Connect (OSTI)

    Poineau, Frederic [University of Nevada, Las Vegas; Yeamans, Charles B. [University of California, Berkeley; Cerefice, Gary S. [University of Nevada, Las Vegas; Sattelberger, Alfred P [Argonne National Laboratory (ANL); Czerwinski, Ken R. [University of Nevada, Las Vegas

    2012-01-01

    Uranium mononitride (UN), sesquinitride (U2N3) and dinitride (UN2) were characterized by extended X-Ray absorption fine structure spectroscopy. Analysis on UN indicate the presence of three uranium shells at distances of 3.46(3), 4.89(5) and 6.01(6) A and a nitrogen shell at a distance of 2.46(2) A . For U2N3, two absorbing uranium atoms at different crystallographic positions are present in the structure. One of the uranium atoms is surrounded by nitrogen atoms at 2.28(2) A and by uranium atoms at 3.66(4) and 3.95(4) A . The second type of uranium atom is surrounded by nitrogen atoms at 2.33(2) and 2.64(3) A and by uranium atoms at 3.66(4), 3.95(4) and 5.31(5) A . Results on UN2 indicate two uranium shells at 3.71(4) and 5.32(5) A and two nitrogen shells at 2.28(2).

  6. Vibronic fine structure in high-resolution x-ray absorption spectra from ion-bombarded boron nitride nanotubes

    SciTech Connect (OSTI)

    Petravic, Mladen; Peter, Robert; Varasanec, Marijana; Li Luhua; Chen Ying; Cowie, Bruce C. C.

    2013-05-15

    The authors have applied high-resolution near-edge x-ray absorption fine structure measurements around the nitrogen K-edge to study the effects of ion-bombardment on near-surface properties of boron nitride nanotubes. A notable difference has been observed between surface sensitive partial electron yield (PEY) and bulk sensitive total electron yield (TEY) fine-structure measurements. The authors assign the PEY fine structure to the coupling of excited molecular vibrational modes to electronic transitions in NO molecules trapped just below the surface. Oxidation resistance of the boron nitride nanotubes is significantly reduced by low energy ion bombardment, as broken B-N bonds are replaced by N-O bonds involving oxygen present in the surface region. In contrast to the PEY spectra, the bulk sensitive TEY measurements on as-grown samples do not exhibit any fine structure while the ion-bombarded samples show a clear vibronic signature of molecular nitrogen.

  7. X-ray absorption fine structure spectroscopic determination of plutonium speciation at the Rocky Flats environmental technology

    SciTech Connect (OSTI)

    Lezama-pacheco, Juan S; Conradson, Steven D; Clark, David L

    2008-01-01

    X-ray Absorption Fine Structure spectroscopy was used to probe the speciation of the ppm level Pu in thirteen soil and concrete samples from the Rocky Flats Environmental Technology Site in support of the site remediation effort that has been successfully completed since these measurements. In addition to X-ray Absorption Near Edge Spectra, two of the samples yielded Extended X-ray Absorption Fine Structure spectra that could be analyzed by curve-fits. Most of these spectra exhibited features consistent with PU(IV), and more specificaJly, PuO{sub 2+x}-type speciation. Two were ambiguous, possibly indicating that Pu that was originally present in a different form was transforming into PuO{sub 2+x}, and one was interpreted as demonstrating the presence of an unusual Pu(VI) compound, consistent with its source being spills from a PUREX purification line onto a concrete floor and the resultant extreme conditions. These experimental results therefore validated models that predicted that insoluble PuO{sub 2+x} would be the most stable form of Pu in equilibrium with air and water even when the source terms were most likely Pu metal with organic compounds or a Pu fire. A corollary of these models' predictions and other in situ observations is therefore that the minimal transport of Pu that occurred on the site was via the resuspension and mobilization of colloidal particles. Under these conditions, the small amounts of diffusely distributed Pu that were left on the site after its remediation pose only a negligible hazard.

  8. X-ray absorption fine structure (XAFS) analyses of Ni species trapped in graphene sheet of carbon nanofibers

    SciTech Connect (OSTI)

    Ushiro, Mayuko; Uno, Kanae; Fujikawa, Takashi; Sato, Yoshinori; Tohji, Kazuyuki; Watari, Fumio; Chun, W.-J.; Koike, Yuichiro; Asakura, Kiyotaka

    2006-04-01

    Metal impurities in the carbon nanotubes and carbon nanofibers play an important role in understanding their physical and chemical properties. We apply the Ni K-edge x-ray absorption fine structure analyses to the local electronic and geometric structures around embedded Ni impurities used as catalysts in a carbon nanofiber in combination with multiple scattering analyses. We find almost Ni catalysts as metal particles are removed by the purification treatment. Even after the purification, residual 100 ppm Ni species are still absorbed; most of them are in monomer structure with Ni-C bond length 1.83 A, and each of them is substituted for a carbon atom in a graphene sheet.

  9. Determining Orientational Structure of Diamondoid Thiols Attached to Silver Using Near Edge X-ray Absorption Fine Structure Spectroscopy

    SciTech Connect (OSTI)

    Willey, T M; Lee, J I; Fabbri, J D; Wang, D; Nielsen, M; Randel, J C; Schreiner, P R; Fokin, A A; Tkachenko, B A; Fokina, N A; Dahl, J P; Carlson, R K; Terminello, L J; Melosh, N A; van Buuren, T

    2008-10-07

    Near-edge x-ray absorption fine structure spectroscopy (NEXAFS) is a powerful tool for determination of molecular orientation in self-assembled monolayers and other surface-attached molecules. A general framework for using NEXAFS to simultaneously determine molecular tilt and twist of rigid molecules attached to surfaces is presented. This framework is applied to self-assembled monolayers of higher diamondoid, hydrocarbon molecules with cubic-diamond-cage structures. Diamondoid monolayers chemisorbed on metal substrates are known to exhibit interesting electronic and surface properties. This work compares molecular orientation in monolayers prepared on silver substrates using two different thiol positional isomers of [121]tetramantane, and thiols derived from two different pentamantane structural isomers, [1212]pentamantane and [1(2,3)4]pentamantane. The observed differences in monolayer structure demonstrate the utility and limitations of NEXAFS spectroscopy and the framework. The results also demonstrate the ability to control diamondoid assembly, in particular the molecular orientational structure, providing a flexible platform for the modification of surface properties with this exciting new class of nanodiamond materials.

  10. Studies of vibrational properties in Ga stabilized delta-Pu by extended X-ray absorption fine structure

    SciTech Connect (OSTI)

    Allen, P.G.; Henderson, A.L.; Sylwester, E.R.; Turchi, P.E.A.; Shen, T.H.; Gallegos, G.F.; Booth, C.H.

    2002-02-14

    Temperature dependent extended x-ray absorption fine structure (EXAFS) spectra were measured for a 3.3 at. % Ga stabilized Pu alloy over the range T= 20 - 300 K. EXAFS data were acquired at both the Ga K-edge and the Pu L{sub III} edge. Curve-fits were performed to the first shell interactions to obtain pair-distance distribution widths, {sigma}, as a function of temperature. The temperature dependence of {sigma}(T) was accurately modeled using a correlated-Debye model for the lattice vibrational properties, suggesting Debye-like behavior in this material. Using this formalism, we obtain pair-specific correlated-Debye temperatures, {Theta}{sub cD}, of 110.7 {+-} 1.7 K and 202.6 {+-} 3.7 K, for the Pu-Pu and Ga-Pu pairs, respectively. The result for the Pu-{Theta}{sub cD} value compares well with previous vibrational studies on {delta}-Pu. In addition, our results represent the first unambiguous determination of Ga-specific vibrational properties in Pu-Ga alloys, i.e, {Theta}{sub cD} for the Ga-Pu pair. Because the Debye temperature can be related to a measure of the lattice stiffness, these results indicate the Ga-Pu bonds are significantly stronger than the Pu-Pu bonds. This effect has important implications for lattice stabilization mechanisms in these alloys.

  11. Near-edge X-ray absorption fine-structure spectroscopy of naphthalene diimide-thiophene co-polymers

    SciTech Connect (OSTI)

    Gann, Eliot; McNeill, Christopher R., E-mail: christopher.mcneill@monash.edu [Department of Materials Engineering, Monash University, Wellington Road, Clayton, Victoria 3800 (Australia); Szumilo, Monika; Sirringhaus, Henning [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)] [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Sommer, Michael [Institute of Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, 79104 Freiburg (Germany)] [Institute of Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, 79104 Freiburg (Germany); Maniam, Subashani; Langford, Steven J. [School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800 (Australia)] [School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800 (Australia); Thomsen, Lars [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)] [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)

    2014-04-28

    Near-edge X-ray absorption fine-structure (NEXAFS) spectroscopy is an important tool for probing the structure of conjugated polymer films used in organic electronic devices. High-performance conjugated polymers are often donor-acceptor co-polymers which feature a repeat unit with multiple functional groups. To facilitate better application of NEXAFS spectroscopy to the study of such materials, improved understanding of the observed NEXAFS spectral features is required. In order to examine how the NEXAFS spectrum of a donor-acceptor co-polymer relates to the properties of the sub-units, a series of naphthalene diimide-thiophene-based co-polymers have been studied where the nature and length of the donor co-monomer has been systematically varied. The spectra of these materials are compared with that of a thiophene homopolymer and naphthalene diimide monomer enabling peak assignment and the influence of inter-unit electronic coupling to be assessed. We find that while it is possible to attribute peaks within the ?* manifold as arising primarily due to the naphthalene diimide or thiophene sub-units, very similar dichroism of these peaks is observed indicating that it may not be possible to separately probe the molecular orientation of the separate sub-units with carbon K-edge NEXAFS spectroscopy.

  12. An X-ray Absorption Fine Structure study of Au adsorbed onto the non-metabolizing cells of two soil bacterial species

    SciTech Connect (OSTI)

    Song, Zhen; Kenney, Janice P.L.; Fein, Jeremy B.; Bunker, Bruce A.

    2015-02-09

    Gram-positive and Gram-negative bacterial cells can remove Au from Au(III)-chloride solutions, and the extent of removal is strongly pH dependent. In order to determine the removal mechanisms, X-ray Absorption Fine Structure (XAFS) spectroscopy experiments were conducted on non-metabolizing biomass of Bacillus subtilis and Pseudomonas putida with fixed Au(III) concentrations over a range of bacterial concentrations and pH values. X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) data on both bacterial species indicate that more than 90% of the Au atoms on the bacterial cell walls were reduced to Au(I). In contrast to what has been observed for Au(III) interaction with metabolizing bacterial cells, no Au(0) or Au-Au nearest neighbors were observed in our experimental systems. All of the removed Au was present as adsorbed bacterial surface complexes. For both species, the XAFS data suggest that although Au-chloride-hydroxide aqueous complexes dominate the speciation of Au in solution, Au on the bacterial cell wall is characterized predominantly by binding of Au atoms to sulfhydryl functional groups and amine and/or carboxyl functional groups, and the relative importance of the sulfhydryl groups increases with increasing pH and with decreasing Au loading. The XAFS data for both microorganism species suggest that adsorption is the first step in the formation of Au nanoparticles by bacteria, and the results enhance our ability to account for the behavior of Au in bacteria-bearing geologic systems.

  13. Versatile plug flow catalytic cell for in situ transmission/fluorescence x-ray absorption fine structure measurements

    SciTech Connect (OSTI)

    Centomo, P.; Zecca, M. [Dipartimento di Scienze Chimiche, via Marzolo 1, Universita degli Studi di Padova, 35131 Padova (Italy); Meneghini, C. [Dipartimento di Scienze, via della Vasca Navale 84, Universita di Roma TRE, 00146 Roma (Italy)

    2013-05-15

    A novel flow-through catalytic cell has been developed for in situ x-ray absorption spectroscopy (XAS) experiments on heterogeneous catalysts under working conditions and in the presence of a liquid and a gas phase. The apparatus allows to carry out XAS measurements in both the transmission and fluorescence modes, at moderate temperature (from RT to 50-80 Degree-Sign C) and low-medium gas pressure (up to 7-8 bars). The materials employed are compatible with several chemicals such as those involved in the direct synthesis of hydrogen peroxide (O{sub 2}, H{sub 2}, H{sub 2}O{sub 2}, methanol). The versatile design of the cell allows to fit it to different experimental setups in synchrotron radiation beamlines. It was used successfully for the first time to test nanostructured Pd catalysts during the direct synthesis of hydrogen peroxide (H{sub 2}O{sub 2}) in methanol solution from dihydrogen and dioxygen.

  14. Interrogation of Surface, Skin, and Core Orientation in Thermotropic Liquid-Crystalline Copolyester Moldings by Near-Edge X-ray Absorption Fine Structure and Wide-Angle X-ray Scattering

    SciTech Connect (OSTI)

    Rendon,S.; Bubeck, R.; Thomas, L.; Burghardt, W.; Hexemer, A.; Fischer, D.

    2007-01-01

    Injection molding thermotropic liquid-crystalline polymers (TLCPs) usually results in the fabrication of molded articles that possess complex states of orientation that vary greatly as a function of thickness. 'Skin-core' morphologies are often observed in TLCP moldings. Given that both 'core' and 'skin' orientation states may often differ both in magnitude and direction, deconvolution of these complex orientation states requires a method to separately characterize molecular orientation in the surface region. A combination of two-dimensional wide-angle X-ray scattering (WAXS) in transmission and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is used to probe the molecular orientation in injection molded plaques fabricated from a 4,4'-dihydroxy-{alpha}-methylstilbene (DH{alpha}MS)-based thermotropic liquid crystalline copolyester. Partial electron yield (PEY) mode NEXAFS is a noninvasive ex situ characterization tool with exquisite surface sensitivity that samples to a depth of 2 nm. The effects of plaque geometry and injection molding processing conditions on surface orientation in the regions on- and off- axis to the centerline of injection molded plaques are presented and discussed. Quantitative comparisons are made between orientation parameters obtained by NEXAFS and those from 2D WAXS in transmission, which are dominated by the microstructure in the skin and core regions. Some qualitative comparisons are also made with 2D WAXS results from the literature.

  15. Effect of Residence Time on Ni-Sorption Mechanisms on Clay and Oxide Minerals: An X-ray Absorption Fine Structure (XAFS) Study

    E-Print Network [OSTI]

    Sparks, Donald L.

    Effect of Residence Time on Ni-Sorption Mechanisms on Clay and Oxide Minerals: An X-ray Absorption minerals is typically fast initially, then the rates gradually diminish. In the literature the decline

  16. PRELIMINARY IN-SITU X-RAY ABSORPTION FINE STRUCTURE EXAMINATION OF PT/C AND PTCO/C CATHODE CATALYSTS IN AN OPERATIONAL POLYMER ELECTROLYTE FUEL CELL

    SciTech Connect (OSTI)

    Phelan, B.T.; Myers, D.J.; Smith, M.C.

    2009-01-01

    State-of-the-art polymer electrolyte fuel cells require a conditioning period to reach optimized cell performance. There is insuffi cient understanding about the behavior of catalysts during this period, especially with regard to the changing environment of the cathode electrocatalyst, which is typically Pt nanoparticles supported on high surface area Vulcan XC-72 carbon (Pt/C). The purpose of this research was to record preliminary observations of the changing environment during the conditioning phase using X-Ray Absorption Fine Structure (XAFS) spectroscopy. XAFS was recorded for a Pt/C cathode at the Pt L3-edge and a PtCo/C cathode at both the Pt L3-edge and Co K-edge. Using precision machined graphite cell-blocks, both transmission and fl uorescence data were recorded at Sector 12-BM-B of Argonne National Laboratory’s Advanced Photon Source. The fl uorescence and transmission edge steps allow for a working description of the changing electrocatalyst environment, especially water concentration, at the anode and cathode as functions of operating parameters. These features are discussed in the context of how future analysis may correlate with potential, current and changing apparent thickness of the membrane electrode assembly through loss of catalyst materials (anode, cathode, carbon support). Such direct knowledge of the effect of the conditioning protocol on the electrocatalyst may lead to better catalyst design. In turn, this may lead to minimizing, or even eliminating, the conditioning period.

  17. Laser plasma x-ray source for ultrafast time-resolved x-ray absorption spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Miaja-Avila, L.; O'Neil, G. C.; Uhlig, J.; Cromer, C. L.; Dowell, M. L.; Jimenez, R.; Hoover, A. S.; Silverman, K. L.; Ullom, J. N.

    2015-03-02

    We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 ?m FWHM x-ray spot size, containing ~106 photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >107 laser pulses, we also presentmore »data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.« less

  18. Electronic structure of titania aerogels: Soft x-ray absorption...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Electronic structure of titania aerogels: Soft x-ray absorption study Citation Details In-Document Search Title: Electronic structure of titania aerogels: Soft...

  19. SMB, X-ray Absorption Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust, High-Throughput Analysis of Protein1-0845*RV 14800Small Angle X-Ray Scattering Home

  20. Femtosecond x-ray absorption spectroscopy with hard x-ray free electron laser

    SciTech Connect (OSTI)

    Katayama, Tetsuo; Togashi, Tadashi; Tono, Kensuke; Kameshima, Takashi; Inubushi, Yuichi; Sato, Takahiro; Hatsui, Takaki; Yabashi, Makina; Obara, Yuki; Misawa, Kazuhiko; Bhattacharya, Atanu; Kurahashi, Naoya; Ogi, Yoshihiro; Suzuki, Toshinori; Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198

    2013-09-23

    We have developed a method of dispersive x-ray absorption spectroscopy with a hard x-ray free electron laser (XFEL), generated by a self-amplified spontaneous emission (SASE) mechanism. A transmission grating was utilized for splitting SASE-XFEL light, which has a relatively large bandwidth (?E/E ? 5 × 10{sup ?3}), into several branches. Two primary split beams were introduced into a dispersive spectrometer for measuring signal and reference spectra simultaneously. After normalization, we obtained a Zn K-edge absorption spectrum with a photon-energy range of 210 eV, which is in excellent agreement with that measured by a conventional wavelength-scanning method. From the analysis of the difference spectra, the noise ratio was evaluated to be ?3 × 10{sup ?3}, which is sufficiently small to trace minute changes in transient spectra induced by an ultrafast optical laser. This scheme enables us to perform single-shot, high-accuracy x-ray absorption spectroscopy with femtosecond time resolution.

  1. A laboratory-based hard x-ray monochromator for high-resolution x-ray emission spectroscopy and x-ray absorption near edge structure measurements

    SciTech Connect (OSTI)

    Seidler, G. T. Mortensen, D. R.; Remesnik, A. J.; Pacold, J. I.; Ball, N. A.; Barry, N.; Styczinski, M.; Hoidn, O. R.

    2014-11-15

    We report the development of a laboratory-based Rowland-circle monochromator that incorporates a low power x-ray (bremsstrahlung) tube source, a spherically bent crystal analyzer, and an energy-resolving solid-state detector. This relatively inexpensive, introductory level instrument achieves 1-eV energy resolution for photon energies of ?5 keV to ?10 keV while also demonstrating a net efficiency previously seen only in laboratory monochromators having much coarser energy resolution. Despite the use of only a compact, air-cooled 10 W x-ray tube, we find count rates for nonresonant x-ray emission spectroscopy comparable to those achieved at monochromatized spectroscopy beamlines at synchrotron light sources. For x-ray absorption near edge structure, the monochromatized flux is small (due to the use of a low-powered x-ray generator) but still useful for routine transmission-mode studies of concentrated samples. These results indicate that upgrading to a standard commercial high-power line-focused x-ray tube or rotating anode x-ray generator would result in monochromatized fluxes of order 10{sup 6}–10{sup 7} photons/s with no loss in energy resolution. This work establishes core technical capabilities for a rejuvenation of laboratory-based hard x-ray spectroscopies that could have special relevance for contemporary research on catalytic or electrical energy storage systems using transition-metal, lanthanide, or noble-metal active species.

  2. Structural characterization of Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} as a function of temperature using neutron powder diffraction and extended X-ray absorption fine structure techniques

    SciTech Connect (OSTI)

    Mansour, A. N.; Wong-Ng, W.; Huang, Q.; Tang, W.; Thompson, A.; Sharp, J.

    2014-08-28

    The structure of Bi{sub 2}Te{sub 3} (Seebeck coefficient Standard Reference Material (SRM™ 3451)) and the related phase Sb{sub 2}Te{sub 3} have been characterized as a function of temperature using the neutron powder diffraction (NPD) and the extended X-ray absorption fine structure (EXAFS) techniques. The neutron structural studies were carried out from 20?K to 300?K for Bi{sub 2}Te{sub 3} and from 10?K to 298?K for Sb{sub 2}Te{sub 3}. The EXAFS technique for studying the local structure of the two compounds was conducted from 19?K to 298?K. Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} are isostructural, with a space group of R3{sup ¯}m. The structure consists of repeated quintuple layers of atoms, Te2-M-Te1-M-Te2 (where M?=?Bi or Sb) stacking along the c-axis of the unit cell. EXAFS was used to examine the bond distances and static and thermal disorders for the first three shells of Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} as a function of temperature. The temperature dependencies of thermal disorders were analyzed using the Debye and Einstein models for lattice vibrations. The Debye and Einstein temperatures for the first two shells of Bi{sub 2}Te{sub 3} are similar to those of Sb{sub 2}Te{sub 3} within the uncertainty in the data. However, the Debye and Einstein temperatures for the third shell of Bi-Bi are significantly lower than those of the third shell of Sb-Sb. The Einstein temperature for the third shell is consistent with a soft phonon mode in both Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3}. The lower Einstein temperature of Bi-Bi relative to Sb-Sb is consistent with the lower value of thermal conductivity of Bi{sub 2}Te{sub 3} relative to Sb{sub 2}Te{sub 3}.

  3. Effects of {pi}-stacking interactions on the near carbon K-edge x-ray absorption fine structure: A theoretical study of the ethylene pentamer and the phthalocyanine dimer

    SciTech Connect (OSTI)

    Linares, Mathieu; Stafstroem, Sven; Norman, Patrick [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden)

    2009-03-14

    X-ray absorption spectra have been determined for ethylene and free base phthalocyanine at the carbon K-edge with use of the complex polarization propagator method combined with Kohn-Sham density functional theory and the Coulomb attenuated method B3LYP exchange-correlation functional. Apart from isolated molecules, the study includes {pi}-stacked systems of the phthalocyanine dimer and the ethylene dimer, trimer, tetramer, and pentamer. For ethylene, {pi}-stacking involves a reduction in transition energy of the valence {pi}*-band by some 70 meV and large spectral changes (regarding also shape and intensity) of the Rydberg bands. For phthalocyanine, there are large spectral changes in the entire valence {pi}*-part of the spectrum.

  4. Metal binding in proteins: machine learning complements X-ray absorption spectroscopy

    E-Print Network [OSTI]

    Passerini, Andrea

    Metal binding in proteins: machine learning complements X-ray absorption spectroscopy Marco Lippi1 for the identification of metalloproteins and metal binding sites on a genome scale. An extensive evaluation conducted in combination with X- ray absorption spectroscopy shows the great potentiality of the approach. 1 Metal binding

  5. Combining X-ray Absorption and X-ray Diffraction Techniques for in Situ Studies of Chemical Transformations in Heterogeneous Catalysis: Advantages and Limitations

    SciTech Connect (OSTI)

    Frenkel, A.I.; Hanson, J.; Wang, Q.; Marinkovic, N.; Chen, J.G.; Barrio, L.; Si, R.; Lopez Camara, A.; Estrella, A.M.; Rodriguez, J.A.

    2011-08-05

    Recent advances in catalysis instrumentations include synchrotron-based facilities where time-resolved X-ray scattering and absorption techniques are combined in the same in situ or operando experiment to study catalysts at work. To evaluate the advances and limitations of this method, we performed a series of experiments at the new XAFS/XRD instrument in the National Synchrotron Light Source. Nearly simultaneous X-ray diffraction (XRD) and X-ray absorption fine-structure (XAFS) measurements of structure and kinetics of several catalysts under reducing or oxidizing conditions have been performed and carefully analyzed. For CuFe{sub 2}O{sub 4} under reducing conditions, the combined use of the two techniques allowed us to obtain accurate data on kinetics of nucleation and growth of metallic Cu. For the inverse catalyst CuO/CeO{sub 2} that underwent isothermal reduction (with CO) and oxidation (with O{sub 2}), the XAFS data measured in the same experiment with XRD revealed strongly disordered Cu species that went undetected by diffraction. These and other examples emphasize the unique sensitivity of these two complementary methods to follow catalytic processes in the broad ranges of length and time scales.

  6. Combining X-ray Absorption and X-ray Diffraction Techniques for in Situ Studies of Chemical Transformations in Heterogeneous Catalysis:Advantages and Limitations

    SciTech Connect (OSTI)

    A Frenkel; Q Wang; N Marinkovic; J Chen; L Barrio; R Si; A Lopez Camara; A Estella; J Rodriquez; J Hanson

    2011-12-31

    Recent advances in catalysis instrumentations include synchrotron-based facilities where time-resolved X-ray scattering and absorption techniques are combined in the same in situ or operando experiment to study catalysts at work. To evaluate the advances and limitations of this method, we performed a series of experiments at the new XAFS/XRD instrument in the National Synchrotron Light Source. Nearly simultaneous X-ray diffraction (XRD) and X-ray absorption fine-structure (XAFS) measurements of structure and kinetics of several catalysts under reducing or oxidizing conditions have been performed and carefully analyzed. For CuFe{sub 2}O{sub 4} under reducing conditions, the combined use of the two techniques allowed us to obtain accurate data on kinetics of nucleation and growth of metallic Cu. For the inverse catalyst CuO/CeO{sub 2} that underwent isothermal reduction (with CO) and oxidation (with O{sub 2}), the XAFS data measured in the same experiment with XRD revealed strongly disordered Cu species that went undetected by diffraction. These and other examples emphasize the unique sensitivity of these two complementary methods to follow catalytic processes in the broad ranges of length and time scales.

  7. X-ray-absorption study of CuBr at high pressure

    SciTech Connect (OSTI)

    Tranquada, J.M.; Ingalls, R.

    1986-09-15

    The x-ray-absorption spectrum of cuprous bromide has been measured as a function of pressure. The x-ray-absorption near-edge structure proved to be an excellent indicator of high-pressure phase transitions in this material. The normalized ''white-line'' peak heights at both the Cu and Br K-italic edges decreased on entering the tetragonal phase and increased in going to the NaCl structure. The zinc-blende to tetragonal phase transition took place over a very narrow pressure range centered at 46 +- 5 kbar. The transformation from the tetragonal to the NaCl structure, on the other hand, showed a broad mixed-phase region, suggesting a nucleation-and-growth mechanism for the transition. The mixed-phase region was centered at 75 +- 6 kbar. No evidence of a phase between the zinc-blende and tetragonal phases was observed, presumably because it does not exist. Analysis of the extended x-ray-absorption fine-structure (EXAFS) clearly showed that there is no change in coordination in going from the zinc-blende to the tetragonal phase although the nearest-neighbor distance increases slightly. A much larger increase in R-italic/sub 1/ occurs at the transition to the NaCl structure, where the coordination increases from 4 to 6. The mean-square deviation in the nearest-neighbor bond length, sigma/sub 1//sup 2/, appears to be a fairly smooth function of nearest-neighbor distance, decreasing (or increasing) as R-italic/sub 1/ decreases (or increases) more or less independent of structure. Evidence from the literature was presented to suggest that the zinc-blende to tetragonal transition in CuBr (and also CuCl) should occur by shear deformation.

  8. Americium characterization by X-ray fluorescence and absorption spectroscopy in plutonium uranium mixed oxide

    SciTech Connect (OSTI)

    Degueldre, Claude Cozzo, Cedric; Martin, Matthias; Grolimund, Daniel; Mieszczynski, Cyprian

    2013-06-01

    Plutonium uranium mixed oxide (MOX) fuels are currently used in nuclear reactors. The actinides in these fuels need to be analyzed after irradiation for assessing their behaviour with regard to their environment and the coolant. In this work the study of the atomic structure and next-neighbour environment of Am in the (Pu,U)O? lattice in an irradiated (60 MW d kg?¹) MOX sample was performed employing micro-X-ray fluorescence (µ-XRF) and micro-X-ray absorption fine structure (µ-XAFS) spectroscopy. The chemical bonds, valences and stoichiometry of Am (~0.66 wt%) are determined from the experimental data gained for the irradiated fuel material examined in its peripheral zone (rim) of the fuel. In the irradiated sample Am builds up as Am³? species within an [AmO?]¹³? coordination environment (e.g. >90%) and no (<10%) Am(IV) or (V) can be detected in the rim zone. The occurrence of americium dioxide is avoided by the redox buffering activity of the uranium dioxide matrix. - Graphical abstract: Americium LIII XAFS spectra recorded for the irradiated MOX sub-sample in the rim zone for a 300 ?m×300 ?m beam size area investigated over six scans of 4 h. The records remain constant during multi-scan. The analysis of the XAFS signal shows that Am is found as trivalent in the UO? matrix. This analytical work shall open the door of very challenging analysis (speciation of fission product and actinides) in irradiated nuclear fuels. - Highlights: • Americium was characterized by microX-ray absorption spectroscopy in irradiated MOX fuel. • The americium redox state as determined from XAS data of irradiated fuel material was Am(III). • In the sample, the Am³? face an AmO?¹³?coordination environment in the (Pu,U)O? matrix. • The americium dioxide is reduced by the uranium dioxide matrix.

  9. X-ray absorption spectroscopic studies of the active sites of nickel- and copper-containing metalloproteins

    SciTech Connect (OSTI)

    Tan, G.O.

    1993-06-01

    X-ray absorption spectroscopy (XAS) is a useful tool for obtaining structural and chemical information about the active sites of metalloproteins and metalloenzymes. Information may be obtained from both the edge region and the extended X-ray absorption fine structure (EXAFS) or post-edge region of the K-edge X-ray absorption spectrum of a metal center in a compound. The edge contains information about the valence electronic structure of the atom that absorbs the X-rays. It is possible in some systems to infer the redox state of the metal atom in question, as well as the geometry and nature of ligands connected to it, from the features in the edge in a straightforward manner. The EXAFS modulations, being produced by the backscattering of the ejected photoelectron from the atoms surrounding the metal atom, provide, when analyzed, information about the number and type of neighbouring atoms, and the distances at which they occur. In this thesis, analysis of both the edge and EXAFS regions has been used to gain information about the active sites of various metalloproteins. The metalloproteins studied were plastocyanin (Pc), laccase and nickel carbon monoxide dehydrogenase (Ni CODH). Studies of Cu(I)-imidazole compounds, related to the protein hemocyanin, are also reported here.

  10. Combined in Situ X-ray absorption and diffuse reflectance infraredspectroscopy: An attractive tool for catalytic investigations

    SciTech Connect (OSTI)

    Marinkovic, N.S.; Ehrlich, S.; Wang, Q.; Barrio, L.; Khalid, S.; et.al.

    2010-11-24

    Catalysis investigations are often followed in a range of spectroscopic techniques. While diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) can be done on a bench-top instrument, X-ray absorption spectroscopy (XAS) techniques, such as extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) require synchrotron light. In order to ensure the same conditions during in situ catalysis for each method, a combined XAS/DRIFTS has been developed at beamline X18A at the National Synchrotron Light Source, Brookhaven National Laboratory. A rapid-scan FTIR spectrometer capable of both mid- and far-infrared measurements is equipped with an arm to redirect the IR beam outside the spectrometer. An in situ reaction chamber, equipped with glassy carbon windows for X-ray light and a KBr window for IR light passage is installed firmly on the arm. The reaction cell can be heated to 600 C and allows passage of gases through the catalyst so that both XAS and DRIFTS techniques can be done simultaneously in controlled environment conditions. Together with a fast-moving monochromator for quick-EXAFS and mass-spectrometric residual gas analysis, this new tool is a powerful method for testing catalytic reactions in real time.

  11. Phase Effects on Mesoscale Object X-ray Absorption Images

    SciTech Connect (OSTI)

    Martz, Jr., H E; Aufderheide, M B; Barty, A; Lehman, S K; Kozioziemski, B J; Schneberk, D J

    2004-09-24

    At Lawrence Livermore National Laboratory particular emphasis is being placed on the nondestructive characterization (NDC) of 'mesoscale' objects.[Martz and Albrecht 2003] We define mesoscale objects as objects that have mm extent with {micro}m features. Here we confine our discussions to x-ray imaging methods applicable to mesoscale object characterization. The goal is object recovery algorithms including phase to enable emerging high-spatial resolution x-ray imaging methods to ''see'' inside or image mesoscale-size materials and objects. To be successful our imaging characterization effort must be able to recover the object function to one micrometer or better spatial resolution over a few millimeters field-of-view with very high contrast.

  12. A table-top femtosecond time-resolved soft x-ray transient absorption spectrometer

    SciTech Connect (OSTI)

    Leone, Stephen; Loh, Zhi-Heng; Khalil, Munira; Correa, Raoul E.; Leone, Stephen R.

    2008-05-21

    A laser-based, table-top instrument is constructed to perform femtosecond soft x-ray transient absorption spectroscopy. Ultrashort soft x-ray pulses produced via high-order harmonic generation of the amplified output of a femtosecond Ti:sapphire laser system are used to probe atomic core-level transient absorptions in atoms and molecules. The results provide chemically specific, time-resolved dynamics with sub-50-fs time resolution. In this setup, high-order harmonics generated in a Ne-filled capillary waveguide are refocused by a gold-coated toroidal mirror into the sample gas cell, where the soft x-ray light intersects with an optical pump pulse. The transmitted high-order harmonics are spectrally dispersed with a home-built soft x-ray spectrometer, which consists of a gold-coated toroidal mirror, a uniform-line spaced plane grating, and a soft x-ray CCD camera. The optical layout of the instrument, design of the soft x-ray spectrometer, and spatial and temporal characterization of the high-order harmonics are described. Examples of static and time-resolved photoabsorption spectra collected on this apparatus are presented.

  13. Magnetic circular dichroism in x-ray absorption and core-level photoemission

    SciTech Connect (OSTI)

    Tobin, J.G.; Waddill, G.D.; Gouder, T.H.; Colmenares, C.A.; Pappas, D.P.

    1993-03-17

    Here is reported observation of magnetic circular dichroism in both x-ray absorption and core-level photoemission of ultra thin magnetic films using circularly polarized x-rays. Iron films (1--4 ML) grown on a Cu(001) substrate at 150 K and magnetized perpendicular to the surface show dramatic changes in the L{sub 2,3} branching ratio for different x-ray polarizations. For linearly-polarized x-rays perpendicular to the magnetic axis of the sample the branching ratio was 0.75. For films {ge} 2 ML, this ratio varied from 0.64 to 0.85 for photon spin parallel and anti-parallel, respectively, to the magnetic axis. This effect was observed either by changing the x-ray helicity for a fixed magnetic axis, or by reversing the magnetic axis for a fixed x-ray helicity. Our observation can be analyzed within a simple one-electron picture, if the raw branching ratios are no so that the linear value becomes statistical Furthermore, warming the films to {approximately}300 K eliminated this effect, indicating a loss of magnetization in the film over a temperature range of {approximately}30 K. Finally, reversing the relative orientation of the photon spin and the magnetic axis from parallel to anti-parallel allowed measurement of the exchange splitting of the Fe 2p and 3p core levels which were found to be 0.3 eV and 0.2 eV. respectively. These results are consistent with earlier studies, but the use of off-plane circularly-polarized x-rays from a bending magnet monochromator offers {approximately}2 orders of magnitude greater intensity than typical spin-polarization measurements. Finally, we have performed preliminary x-ray absorption studies of UFe{sub 2}, demonstrating the feasibilty of MCD measurements in 5f as well as 3d materials.

  14. Size-dependent lattice structure of palladium studied by x-ray absorption spectroscopy Chih-Ming Lin,1,

    E-Print Network [OSTI]

    Chen, Yang-Yuan

    Size-dependent lattice structure of palladium studied by x-ray absorption spectroscopy Chih palladium particles, along with bulk material as reference. With decreasing particle size, the extended x and related properties in substrate-free palladium nanoparticles by x-ray absorption spectroscopy XAS mea

  15. Observing heme doming in myoglobin with femtosecond X-ray absorption spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Levantino, M.; Lemke, H. T.; Schirò, G.; Glownia, M.; Cupane, A.; Cammarata, M.

    2015-07-01

    We report time-resolved X-ray absorption measurements after photolysis of carbonmonoxy myoglobin performed at the LCLS X-ray free electron laser with nearly 100 fs (FWHM) time resolution. Data at the Fe K-edge reveal that the photoinduced structural changes at the heme occur in two steps, with a faster (~70 fs) relaxation preceding a slower (~400 fs) one. We tentatively attribute the first relaxation to a structural rearrangement induced by photolysis involving essentially only the heme chromophore and the second relaxation to a residual Fe motion out of the heme plane that is coupled to the displacement of myoglobin F-helix.

  16. Observing heme doming in myoglobin with femtosecond X-ray absorption spectroscopya)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Levantino, M.; Lemke, H. T.; Schirò, G.; Glownia, M.; Cupane, A.; Cammarata, M.

    2015-07-01

    We report time-resolved X-ray absorption measurements after photolysis of carbonmonoxy myoglobin performed at the LCLS X-ray free electron laser with nearly 100 fs (FWHM) time resolution. Data at the Fe K-edge reveal that the photoinduced structural changes at the heme occur in two steps, with a faster (~70 fs) relaxation preceding a slower (~400 fs) one. We tentatively attribute the first relaxation to a structural rearrangement induced by photolysis involving essentially only the heme chromophore and the second relaxation to a residual Fe motion out of the heme plane that is coupled to the displacement of myoglobin F-helix.

  17. ISMabs: A COMPREHENSIVE X-RAY ABSORPTION MODEL FOR THE INTERSTELLAR MEDIUM

    SciTech Connect (OSTI)

    Gatuzz, E.; Mendoza, C.; García, J.; Kallman, T. R.; Gorczyca, T. W. E-mail: claudio@ivic.gob.ve E-mail: timothy.r.kallman@nasa.gov

    2015-02-10

    We present an X-ray absorption model for the interstellar medium, to be referred to as ISMabs, that takes into account both neutral and ionized species of cosmically abundant elements, and includes the most accurate atomic data available. Using high-resolution spectra from eight X-ray binaries obtained with the Chandra High Energy Transmission Grating Spectrometer, we proceed to benchmark the atomic data in the model particularly in the neon K-edge region. Compared with previous photoabsorption models, which solely rely on neutral species, the inclusion of ions leads to improved spectral fits. Fit parameters comprise the column densities of abundant contributors that allow direct estimates of the ionization states. ISMabs is provided in the appropriate format to be implemented in widely used X-ray spectral fitting packages such as XSPEC, ISIS, and SHERPA.

  18. X-ray absorption study of the electronic structure of Mn-doped amorphous Si

    SciTech Connect (OSTI)

    Arenholz, Elke; Zeng, Li; Huegel, A.; Helgren, E.; Hellman, F.; Piamonteze, C.; Arenholz, E.

    2008-03-08

    The electronic structure of Mn in amorphous Si (a-Mn{sub x}Si{sub 1?x}) is studied by X-ray absorption spectroscopy at the Mn L{sub 3,2} edges for x = 0.005-0.18. Except the x = 0.005 sample, which shows a slight signature of Mn{sup 2+} atomic multiplets associated with a local Mn moment, all samples have broad and featureless L{sub 3,2} absorption peaks, corresponding to an itinerant state for all 3d electrons. The broad X-ray absorption spectra exclude the possibility of a localized 3d moment and explain the unexpectedly quenched Mn moment in this magnetically-doped amorphous semiconductor. Such a fully delocalized d state of Mn dopant in Si has not been previously suggested.

  19. Atomic structure of machined semiconducting chips: An x-ray absorption spectroscopy study

    SciTech Connect (OSTI)

    Paesler, M.; Sayers, D.

    1988-12-01

    X-ray absorption spectroscopy (XAS) has been used to examine the atomic structure of chips of germanium that were produced by single point diamond machining. It is demonstrated that although the local (nearest neighbor) atomic structure is experimentally quite similar to that of single crystal specimens information from more distant atoms indicates the presence of considerable stress. An outline of the technique is given and the strength of XAS in studying the machining process is demonstrated.

  20. Chandra X-ray Observations of NGC 4258: Iron Absorption Lines from the Nucleus

    E-Print Network [OSTI]

    A. J. Young; A. S. Wilson

    2003-10-20

    We report sub-arcsecond resolution X-ray imaging spectroscopy of the low luminosity active galactic nucleus of NGC 4258 and its immediate surroundings with the Chandra X-ray Observatory. NGC 4258 was observed four times, with the first two observations separated by one month, followed over a year later by two consecutive observations. The spectrum of the nucleus is well described by a heavily absorbed, hard X-ray power law of variable luminosity, plus a constant, thermal soft X-ray component. We do not detect an iron K alpha emission line with the upper limit to the equivalent width of a narrow, neutral iron line ranging between 94 and 887 eV (90% confidence) for the different observations. During the second observation on 2000-04-17, two narrow absorption features are seen with >99.5% confidence at ~6.4 keV and ~6.9 keV, which we identify as resonant absorption lines of Fe XVIII - Fe XIX K alpha and Fe XXVI K alpha, respectively. In addition, the 6.9 keV absorption line is probably variable on a timescale of ~6000 sec. The absorption lines are analyzed through a curve of growth analysis, which allows the relationship between ionic column and kinematic temperature or velocity dispersion to be obtained for the observed equivalent widths. We discuss the properties of the absorbing gas for both photo and collisionally ionized models. Given that the maser disk is viewed at an inclination i = 82 degrees, the gas responsible for the 6.9 keV absorption line may be in an inner disk, a disk-wind boundary layer or be thermal gas entrained at the base of the jet. The gas which gives rise to the photoelectric absorption may be the same as that which causes the 6.4 keV Fe K alpha absorption provided that the gas has a bulk velocity dispersion of a few thousand km/s. (Abstract abridged).

  1. Instrument for x-ray absorption spectroscopy with in situ electrical control characterizations

    SciTech Connect (OSTI)

    Huang, Chun-Chao; Chang, Shu-Jui; Yang, Chao-Yao; Tseng, Yuan-Chieh [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan (China)] [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan (China); Chou, Hsiung [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China)] [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China)

    2013-12-15

    We report a synchrotron-based setup capable of performing x-ray absorption spectroscopy and x-ray magnetic circular dichroism with simultaneous electrical control characterizations. The setup can enable research concerning electrical transport, element- and orbital-selective magnetization with an in situ fashion. It is a unique approach to the real-time change of spin-polarized electronic state of a material/device exhibiting magneto-electric responses. The performance of the setup was tested by probing the spin-polarized states of cobalt and oxygen of Zn{sub 1-x}Co{sub x}O dilute magnetic semiconductor under applied voltages, both at low (?20 K) and room temperatures, and signal variations upon the change of applied voltage were clearly detected.

  2. Deciphering Ni sequestration in soil ferromanganese nodules by combining x-ray fluorescence, absorption and diffraction at micrometer scales of resolution

    SciTech Connect (OSTI)

    Manceau, Alain; Tamura, Nobumichi; Marcus, Matthew A.; MacDowell, Alastair A.; Celestre, Richard S.; Sublett, Robert E.; Sposito, Garrison; Padmore, Howard A.

    2002-11-06

    X-ray microprobes are among the most important new analytical techniques to emerge from third generation synchrotron facilities. Here we show how X-ray fluorescence, diffraction, and absorption can be used in parallel to determine the structural form of trace elements in heterogeneous matrices at the micrometer-scale of resolution. Scanning X-ray microfluorescence (microSXRF) and microdiffraction (microSXRD) first are used to identify the host solid phase by mapping the distributions of elements and solid species, respectively. Micro-extended X-ray absorption fine structure (microEXAFS) spectroscopy is then used to determine the mechanism of trace element binding by the host phase at the molecular scale. To illustrate the complementary application of these three techniques, we studied how nickel is sequestered in soil ferromanganese nodules, an overwhelmingly complex natural matrix consisting of submicrometer to nanometer sized particles with varying structures and chemical composition s. We show that nickel substitutes for Mn3+ in the manganese layer of the MnO2-Al(OH)3 mixed-layer oxide lithiophorite. The affinity of Ni for lithiophorite was characteristic of micromodules sampled from soils across the U.S.A. and Europe. Since many natural and synthetic materials are heterogeneous at nanometer to micrometer scales, the synergistic use of microSXRF, microSXRD and microEXAFS is expected to have broad applications to earth and materials science.

  3. New Homogeneous Standards by Atomic Layer Deposition for Synchrotron X-ray Fluorescence and Absorption Spectroscopies.

    SciTech Connect (OSTI)

    Butterworth, A.L.; Becker, N.; Gainsforth, Z.; Lanzirotti, A.; Newville, M.; Proslier, T.; Stodolna, J.; Sutton, S.; Tyliszczak, T.; Westphal, A.J.; Zasadzinski, J. (UCB)

    2012-03-13

    Quantification of synchrotron XRF analyses is typically done through comparisons with measurements on the NIST SRM 1832/1833 thin film standards. Unfortunately, these standards are inhomogeneous on small scales at the tens of percent level. We are synthesizing new homogeneous multilayer standards using the Atomic Layer Deposition technique and characterizing them using multiple analytical methods, including ellipsometry, Rutherford Back Scattering at Evans Analytical, Synchrotron X-ray Fluorescence (SXRF) at Advanced Photon Source (APS) Beamline 13-ID, Synchrotron X-ray Absorption Spectroscopy (XAS) at Advanced Light Source (ALS) Beamlines 11.0.2 and 5.3.2.1 and by electron microscopy techniques. Our motivation for developing much-needed cross-calibration of synchrotron techniques is borne from coordinated analyses of particles captured in the aerogel of the NASA Stardust Interstellar Dust Collector (SIDC). The Stardust Interstellar Dust Preliminary Examination (ISPE) team have characterized three sub-nanogram, {approx}1{micro}m-sized fragments considered as candidates to be the first contemporary interstellar dust ever collected, based on their chemistries and trajectories. The candidates were analyzed in small wedges of aerogel in which they were extracted from the larger collector, using high sensitivity, high spatial resolution >3 keV synchrotron x-ray fluorescence spectroscopy (SXRF) and <2 keV synchrotron x-ray transmission microscopy (STXM) during Stardust ISPE. The ISPE synchrotron techniques have complementary capabilities. Hard X-ray SXRF is sensitive to sub-fg mass of elements Z {ge} 20 (calcium) and has a spatial resolution as low as 90nm. X-ray Diffraction data were collected simultaneously with SXRF data. Soft X-ray STXM at ALS beamline 11.0.2 can detect fg-mass of most elements, including cosmochemically important oxygen, magnesium, aluminum and silicon, which are invisible to SXRF in this application. ALS beamline 11.0.2 has spatial resolution better than 25 nm. Limiting factors for Stardust STXM analyses were self-imposed limits of photon dose due to radiation damage concerns, and significant attenuation of <1500 eV X-rays by {approx}80{micro}m thick, {approx}25 mg/cm{sup 3} density silica aerogel capture medium. In practice, the ISPE team characterized the major, light elements using STXM (O, Mg, Al, Si) and the heavier minor and trace elements using SXRF. The two data sets overlapped only with minor Fe and Ni ({approx}1% mass abundance), providing few quantitative cross-checks. New improved standards for cross calibration are essential for consortium-based analyses of Stardust interstellar and cometary particles, IDPs. Indeed, they have far reaching application across the whole synchrotron-based analytical community. We have synthesized three ALD multilayers simultaneously on silicon nitride membranes and silicon and characterized them using RBS (on Si), XRF (on Si{sub 3}N{sub 4}) and STXM/XAS (holey Si{sub 3}N{sub 4}). The systems we have started to work with are Al-Zn-Fe and Y-Mg-Er. We have found these ALD multi-layers to be uniform at {micro}m- to nm scales, and have found excellent consistency between four analytical techniques so far. The ALD films can also be used as a standard for e-beam instruments, eg., TEM EELS or EDX. After some early issues with the consistency of coatings to the back-side of the membrane windows, we are confident to be able to show multi-analytical agreement to within 10%. As the precision improves, we can use the new standards to verify or improve the tabulated cross-sections.

  4. Local structure of Fe in Fe-doped misfit-layered calcium cobaltite: An X-ray absorption spectroscopy study

    SciTech Connect (OSTI)

    Prasoetsopha, Natkrita; Pinitsoontorn, Supree; Bootchanont, Atipong; Kidkhunthod, Pinit; Srepusharawoot, Pornjuk; Kamwanna, Teerasak; Amornkitbamrung, Vittaya; Kurosaki, Ken; Yamanaka, Shinsuke

    2013-08-15

    Polycrystalline Ca{sub 3}Co{sub 4?x}Fe{sub x}O{sub 9+?} ceramics (x=0, 0.01, 0.03, 0.05) were fabricated using a simple thermal hydro-decomposition method and a spark plasma sintering technique. Thermoelectric property measurements showed that increasing Fe concentration resulted in a decrease in electrical resistivity, thermopower and thermal conductivity, leading to an improvement in the dimensionless figure-of-merit, >35% for x=0.05 at 1073 K. An X-ray absorption spectroscopy technique was used to investigate the local structure of Fe ions in the Ca{sub 3}Co{sub 4?x}Fe{sub x}O{sub 9+?} structure for the first time. By fitting data from the extended X-ray absorption fine structure (EXAFS) spectra and analyzing the X-ray absorption near-edge structure (XANES) spectra incorporated with first principle simulation, it was shown that Fe was substituted for Co in the the Ca{sub 2}CoO{sub 3} (rocksalt, RS) layer rather than in the CoO{sub 2} layer. Variation in the thermoelectric properties as a function of Fe concentration was attributed to charge transfer between the CoO{sub 2} and the RS layers. The origin of the preferential Fe substitution site was investigated considering the ionic radii of Co and Fe and the total energy of the system. - Graphical abstract: The Fe K-edge XANES spectra of: (a) experimental result in comparison to the simulated spectra when Fe atoms were substituted in the RS layer; (b) with magnetic moment; (c) without magnetic moment, and in the CoO{sub 2} layer; (d) with magnetic moment and (e) without magnetic moment. Highlights: • Synthesis, structural studies, and thermoelectric properties of Ca{sub 3}Co{sub 4?x}Fe{sub x}O{sub 9+?}. • Direct evidence for the local structure of the Fe ions in the Ca{sub 3}Co{sub 4?x}Fe{sub x}O{sub 9+?} using XAS analysis. • EXAFS and XANES analysis showed that Fe was likely to be situated in the RS layer structure. • Changes in TE property with Fe content was due to charge transfer between the CoO{sub 2} and the RS layers. • Total energy calculation showed energetically favorable Fe substitution in the RS layer.

  5. X-RAY ABSORPTION ANALYSIS OF NGC 3516: APPEARANCE OF FAST COMPONENTS WITH INCREASED SOURCE FLUX

    SciTech Connect (OSTI)

    Holczer, Tomer; Behar, Ehud, E-mail: tomer@physics.technion.ac.il, E-mail: behar@physics.technion.ac.il [Department of Physics, Technion, Haifa 32000 (Israel)

    2012-03-01

    By analyzing the X-ray spectra of NGC 3516 from 2001 and 2006 obtained with the HETGS spectrometer on board the Chandra X-ray Observatory, we find that the kinematic structure of the outflow can be well represented by four outflow components intrinsic to NGC 3516: -350 {+-} 100 km s{sup -1}, -1500 {+-} 150 km s{sup -1}, -2600 {+-} 200 km s{sup -1}, and -4000 {+-} 400 km s{sup -1}. A local component at z = 0 could be confused in the spectrum with intrinsic component 3. Components 1 and 2 have a broad range of ionization manifested by absorption from 23 different charge states of Fe. Components 3 and 4 are more highly ionized and show absorption from only nine different charge states of Fe. However, we were able to reconstruct the absorption measure distribution for all four. The total column density of each component is N{sub H} = (1.8 {+-} 0.5) Multiplication-Sign 10{sup 22} cm{sup -2}, (2.5 {+-} 0.3) Multiplication-Sign 10{sup 22} cm{sup -2}, (6.9 {+-} 4.3) Multiplication-Sign 10{sup 22} cm{sup -2}, and (5.4 {+-} 1.2) Multiplication-Sign 10{sup 22} cm{sup -2}, respectively. The fast components 3 and 4 appear only in the high state of 2006 and not in 2001, while the slower components persist during both epochs. On the other hand, there is no significant absorption variability within days during 2001 or 2006. We find that the covering factor plays a minor role for the line absorption.

  6. Three-dimensional mapping of nickel oxidation states using full field x-ray absorption near edge structure nanotomography

    SciTech Connect (OSTI)

    Nelson, George J.; Harris, William M.; Izzo, John R. Jr.; Grew, Kyle N.; Chiu, Wilson K. S. [HeteroFoaM Center, a DOE Energy Frontier Research Center, Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Rd., Storrs, Connecticut 06269-3139 (United States); Chu, Yong S. [National Synchrotron Light Source II, Brookhaven National Laboratory, Bldg. 703 Upton, New York 11973-5000 (United States); Yi, Jaemock [Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., Bldg. 438-B007 Argonne, Illinois 60439 (United States); Andrews, Joy C.; Liu Yijin; Pianetta, Piero [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., MS 69 Menlo Park, California 94025 (United States)

    2011-04-25

    The reduction-oxidation cycling of the nickel-based oxides in composite solid oxide fuel cells and battery electrodes is directly related to cell performance. A greater understanding of nickel redox mechanisms at the microstructural level can be achieved in part using transmission x-ray microscopy (TXM) to explore material oxidation states. X-ray nanotomography combined with x-ray absorption near edge structure (XANES) spectroscopy has been applied to study samples containing distinct regions of nickel and nickel oxide (NiO) compositions. Digitally processed images obtained using TXM demonstrate the three-dimensional chemical mapping and microstructural distribution capabilities of full-field XANES nanotomography.

  7. Millisecond Kinetics of Nanocrystal Cation Exchange UsingMicrofluidic X-ray Absorption Spectroscopy

    SciTech Connect (OSTI)

    Chan, Emory M.; Marcus, Matthew A.; Fakra, Sirine; Elnaggar,Mariam S.; Mathies, Richard A.; Alivisatos, A. Paul

    2007-05-07

    We describe the use of a flow-focusing microfluidic reactorto measure the kinetics of theCdSe-to-Ag2Se nanocrystal cation exchangereaction using micro-X-ray absorption spectroscopy (mu XAS). The smallmicroreactor dimensions facilitate the millisecond mixing of CdSenanocrystal and Ag+ reactant solutions, and the transposition of thereaction time onto spatial coordinates enables the in situ observation ofthe millisecond reaction with mu XAS. XAS spectra show the progression ofCdSe nanocrystals to Ag2Se over the course of 100 ms without the presenceof long-lived intermediates. These results, along with supporting stoppedflow absorption experiments, suggest that this nanocrystal cationexchange reaction is highly efficient and provide insight into how thereaction progresses in individual particles. This experiment illustratesthe value and potential of in situ microfluidic X-ray synchrotrontechniques for detailed studies of the millisecond structuraltransformations of nanoparticles and other solution-phase reactions inwhich diffusive mixing initiates changes in local bond structures oroxidation states.

  8. Absorption lines from magnetically-driven winds in X-ray binaries

    E-Print Network [OSTI]

    Chakravorty, S; Ferreira, J; Henri, G; Belmont, R; Clavel, M; Corbel, S; Rodriguez, J; Coriat, M; Drappeau, S; Malzac, J

    2016-01-01

    High resolution X-ray spectra of black hole X-ray binaries (BHBs) show blueshifted absorption lines from disk winds which seem to be equatorial. Winds occur in the Softer (disk-dominated) states of the outburst and are less prominent or absent in the Harder (power-law dominated) states. We use self-similar magneto-hydrodynamic (MHD) accretion-ejection models to explain the disk winds in BHBs. In our models, the density at the base of the outflow from the accretion disk is not a free parameter, but is determined by solving the full set of dynamical MHD equations. Thus the physical properties of the outflow are controlled by the global structure of the disk. We studied different MHD solutions characterized by different values of (a) the disk aspect ratio ($\\varepsilon$) and (b) the ejection efficiency ($p$). We use two kinds of MHD solutions depending on the absence (cold solution) or presence (warm solution) of heating at the disk surface. Such heating could be from e.g. dissipation of energy due to MHD turbul...

  9. Characterization of the Electronic Structure of Silicon Nanoparticles Using X-ray Absorption and Emission

    SciTech Connect (OSTI)

    Vaverka, A M

    2008-07-15

    Resolving open questions regarding transport in nanostructures can have a huge impact on a broad range of future technologies such as light harvesting for energy. Silicon has potential to be used in many of these applications. Understanding how the band edges of nanostructures move as a function of size, surface termination and assembly is of fundamental importance in understanding the transport properties of these materials. In this thesis work I have investigated the change in the electronic structure of silicon nanoparticle assemblies as the surface termination is changed. Nanoparticles are synthesized using a thermal evaporation technique and sizes are determined using atomic force microscopy (AFM). By passivating the particles with molecules containing alcohol groups we are able to modify the size dependent band edge shifts. Both the valence and conduction bands are measured using synchrotron based x-ray absorption spectroscopy (XAS) and soft x-ray fluorescence (SXF) techniques. Particles synthesized via recrystallization of amorphous silicon/SiO{sub 2} multilayers of thicknesses below 10 nm are also investigated using the synchrotron techniques. These samples also show quantum confinement effects but the electronic structure is different from those synthesized via evaporation methods. The total bandgap is determined for all samples measured. The origins of these differences in the electronic structures are discussed.

  10. A doubly curved elliptical crystal spectrometer for the study of localized x-ray absorption in hot plasmas

    SciTech Connect (OSTI)

    Cahill, Adam D. Hoyt, Cad L.; Pikuz, Sergei A.; Shelkovenko, Tania; Hammer, David A.

    2014-10-15

    X-ray absorption spectroscopy is a powerful tool for the diagnosis of plasmas over a wide range of both temperature and density. However, such a measurement is often limited to probing plasmas with temperatures well below that of the x-ray source in order to avoid object plasma emission lines from obscuring important features of the absorption spectrum. This has excluded many plasmas from being investigated by this technique. We have developed an x-ray spectrometer that provides the ability to record absorption spectra from higher temperature plasmas than the usual approach allows without the risk of data contamination by line radiation emitted by the plasma under study. This is accomplished using a doubly curved mica crystal which is bent both elliptically and cylindrically. We present here the foundational work in the design and development of this spectrometer along with initial results obtained with an aluminum x-pinch as the object plasma.

  11. X-ray Absorption Spectroscopy Beamline at the Siam Photon Laboratory

    SciTech Connect (OSTI)

    Klysubun, Wantana; Tarawarakarn, Pongjakr; Sombunchoo, Panidtha; Klinkhieo, Supat; Chaiprapa, Jitrin; Songsiriritthigul, Prayoon

    2007-01-19

    A bending magnet beamline has been constructed and commissioned for x-ray absorption spectroscopy (XAS) at the Siam Photon Laboratory. The photon energy is tunable from 1830 eV to 8000 eV using a Lemmonier-type, fixed-exit double crystal monochromator equipped with InSb(111), Si(111), Ge(220) crystals. Elemental K-edges are then accessible from silicon to iron. A series of low conductance vacuum tubes has been designed and installed between the pumping chambers in the front end to obtain the proper pressure difference between the upstream and the downstream of the front end. Thus lower-energy photons, around K-edges of silicon, phosphorous, and sulfur, can be delivered to the experimental XAS station without being absorbed by a window. In this report, the design of the beamline is described. The commissioning results including the measured photon flux at sample and experimental XAS spectra are presented.

  12. In Situ Diffuse Reflectance IR Spectroscopy and X-ray Absorption Spectroscopy for Fast Catalytic Processes

    SciTech Connect (OSTI)

    N Marinkovic; Q Wang; A Frenkel

    2011-12-31

    A new instrument for synchronous in situ investigations of catalytic materials by IR and X-ray absorption spectroscopies was designed and built at the X18A beamline of the National Synchrotron Light Source of Brookhaven National Laboratory. It provides analytical tools for solving structural, electronic and kinetic problems in catalysis science by two complementary methods. Among the features attractive for catalysis research are the broad range of catalytically active elements that can be investigated (starting with Ni and beyond), the wide range of reaction conditions (temperatures up to 873 K, various reactive gases) and time scales (starting from tens of seconds). The results of several representative experiments that illustrate the attractive capabilities of the new set-up are discussed.

  13. HELIUM IN NATAL H II REGIONS: THE ORIGIN OF THE X-RAY ABSORPTION IN GAMMA-RAY BURST AFTERGLOWS

    SciTech Connect (OSTI)

    Watson, Darach; Andersen, Anja C.; Fynbo, Johan P. U.; Hjorth, Jens; Kruehler, Thomas; Laursen, Peter; Leloudas, Giorgos; Malesani, Daniele [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Zafar, Tayyaba [Laboratoire d'Astrophysique de Marseille - LAM, Universite Aix-Marseille and CNRS, UMR 7326, 38 rue F. Joliot-Curie, F-13388, Marseille Cedex 13 (France); Gorosabel, Javier [Instituto de Astrofisica de Andalucia (IAA-CSIC), Glorieta de la Astronomia s/n, E-18008, Granada (Spain); Jakobsson, Pall, E-mail: darach@dark-cosmology.dk [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland)

    2013-05-01

    Soft X-ray absorption in excess of Galactic is observed in the afterglows of most gamma-ray bursts (GRBs), but the correct solution to its origin has not been arrived at after more than a decade of work, preventing its use as a powerful diagnostic tool. We resolve this long-standing problem and find that absorption by He in the GRB's host H II region is responsible for most of the absorption. We show that the X-ray absorbing column density (N{sub H{sub X}}) is correlated with both the neutral gas column density and with the optical afterglow's dust extinction (A{sub V} ). This correlation explains the connection between dark bursts and bursts with high N{sub H{sub X}} values. From these correlations, we exclude an origin of the X-ray absorption which is not related to the host galaxy, i.e., the intergalactic medium or intervening absorbers are not responsible. We find that the correlation with the dust column has a strong redshift evolution, whereas the correlation with the neutral gas does not. From this, we conclude that the column density of the X-ray absorption is correlated with the total gas column density in the host galaxy rather than the metal column density, in spite of the fact that X-ray absorption is typically dominated by metals. The strong redshift evolution of N{sub H{sub X}}/A{sub V} is thus a reflection of the cosmic metallicity evolution of star-forming galaxies and we find it to be consistent with measurements of the redshift evolution of metallicities for GRB host galaxies. We conclude that the absorption of X-rays in GRB afterglows is caused by He in the H II region hosting the GRB. While dust is destroyed and metals are stripped of all of their electrons by the GRB to great distances, the abundance of He saturates the He-ionizing UV continuum much closer to the GRB, allowing it to remain in the neutral or singly-ionized state. Helium X-ray absorption explains the correlation with total gas, the lack of strong evolution with redshift, as well as the absence of dust, metal or hydrogen absorption features in the optical-UV spectra.

  14. LONG-TERM X-RAY STABILITY AND ULTRAVIOLET VARIABILITY OF THE IONIZED ABSORPTION IN NGC 3783

    SciTech Connect (OSTI)

    Scott, A. E.; Brandt, W. N. [Department of Astronomy and Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802 (United States); Behar, E.; Kaspi, S. [Department of Physics, Technion, Haifa 32000 (Israel); Crenshaw, D. M. [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 605, Atlanta, GA 30303 (United States); Gabel, J. R. [Physics Department, Creighton University, Omaha, NE 68178 (United States); Gibson, R. R. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Kraemer, S. B. [Institute for Astrophysics and Computational Sciences, Department of Physics, The Catholic University of America, Washington, DC 20064 (United States); Turner, T. J., E-mail: amyscott@psu.edu [Department of Physics, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States)

    2014-12-20

    We present the results of recent Chandra High-Energy Transmission Grating Spectrometer and Hubble Space Telescope Cosmic Origins Spectrograph observations of the nearby Seyfert 1 galaxy NGC 3783, which show a strong, nonvarying X-ray warm absorber and physically related and kinematically varying UV absorption. We compare our new observations to high-resolution, high signal-to-noise archival data from 2001, allowing a unique investigation into the long-term variations of the absorption over a 12 yr period. We find no statistically significant changes in the physical properties of the X-ray absorber, but there is a significant drop of ?40% in the UV and X-ray flux and a significant flattening of the underlying X-ray power-law slope. Large kinematic changes are seen in the UV absorbers, possibly due to radial deceleration of the material. Similar behavior is not observed in the X-ray data, likely due to its lower-velocity resolution, which shows an outflow velocity of v {sub out} ? –655 km s{sup –1} in both epochs. The narrow iron K? emission line at 6.4 keV shows no variation between epochs, and its measured width places the material producing the line at a radial distance of ?0.03 pc from the central black hole.

  15. The INTEGRAL/IBIS AGN catalogue I: X-ray absorption properties versus optical classification

    E-Print Network [OSTI]

    Malizia, A; Bazzano, A; Bird, A J; Masetti, N; Panessa, F; Stephen, J B; Ubertini, P

    2012-01-01

    In this work we present the most comprehensive INTEGRAL AGN sample which lists 272 objects. Here we mainly use this sample to study the absorption properties of active galaxies, to probe new AGN classes and to test the AGN unification scheme. We find that half (48%) of the sample is absorbed while the fraction of Compton thick AGN is small (~7%). In line with our previous analysis, we have however shown that when the bias towards heavily absorbed objects which are lost if weak and at large distance is removed, as it is possible in the local Universe, the above fractions increase to become 80% and 17%. We also find that absorption is a function of source luminosity, which implies some evolution in the obscuration properties of AGN. Few peculiar classes, so far poorly studied in the hard X-ray band, have been detected and studied for the first time such as 5 XBONG, 5 type 2 QSOs and 11 LINERs. In terms of optical classification, our sample contains 57% of type 1 and 43% of type 2 AGN; this subdivision is simila...

  16. Finite temperature effects on the X-ray absorption spectra of lithium compounds: First-principles interpretation of X-ray Raman measurements

    SciTech Connect (OSTI)

    Pascal, Tod A.; Prendergast, David, E-mail: dgprendergast@lbl.gov [The Molecular Foundry, Materials Science Division, Lawrence Berkeley National Laboratory (LBNL), Berkeley, California 94720 (United States)] [The Molecular Foundry, Materials Science Division, Lawrence Berkeley National Laboratory (LBNL), Berkeley, California 94720 (United States); Boesenberg, Ulrike; Kostecki, Robert; Richardson, Thomas J. [Environmental Energy Technologies Division, LBNL, Berkeley, California 94720 (United States)] [Environmental Energy Technologies Division, LBNL, Berkeley, California 94720 (United States); Weng, Tsu-Chien; Sokaras, Dimosthenis; Nordlund, Dennis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford, California 94720 (United States)] [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford, California 94720 (United States); McDermott, Eamon; Moewes, Alexander [University of Saskatchewan, Department of Physics and Engineering Physics, Saskatoon, Saskatchewan S7N 5E2 (Canada)] [University of Saskatchewan, Department of Physics and Engineering Physics, Saskatoon, Saskatchewan S7N 5E2 (Canada); Cabana, Jordi [Environmental Energy Technologies Division, LBNL, Berkeley, California 94720 (United States) [Environmental Energy Technologies Division, LBNL, Berkeley, California 94720 (United States); Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60605 (United States)

    2014-01-21

    We elucidate the role of room-temperature-induced instantaneous structural distortions in the Li K-edge X-ray absorption spectra (XAS) of crystalline LiF, Li{sub 2}SO{sub 4}, Li{sub 2}O, Li{sub 3}N, and Li{sub 2}CO{sub 3} using high resolution X-ray Raman spectroscopy (XRS) measurements and first-principles density functional theory calculations within the eXcited electron and Core Hole approach. Based on thermodynamic sampling via ab initio molecular dynamics simulations, we find calculated XAS in much better agreement with experiment than those computed using the rigid crystal structure alone. We show that local instantaneous distortion of the atomic lattice perturbs the symmetry of the Li 1s core-excited-state electronic structure, broadening spectral line-shapes and, in some cases, producing additional spectral features. The excellent agreement with high-resolution XRS measurements validates the accuracy of our first-principles approach to simulating XAS, and provides both accurate benchmarks for model compounds and a predictive theoretical capability for identification and characterization of multi-component systems, such as lithium-ion batteries, under working conditions.

  17. Towards simultaneous measurements of electronic and structural properties in ultra-fast x-ray free electron laser absorption spectroscopy experiments

    SciTech Connect (OSTI)

    Gaudin, J.; Fourment, C.; Cho, B. I.; Engelhorn, K.; Galtier, E.; Harmand, M.; Leguay, P. M.; Lee, H. J.; Nagler, B.; Nakatsutsumi, M.; Ozkan, C.; Störmer, M.; Toleikis, S.; Tschentscher, Th.; Heimann, P. A.; Dorchies, F.

    2014-04-17

    The rapidly growing ultrafast science with X-ray lasers unveils atomic scale processes with unprecedented time resolution bringing the so called “molecular movie” within reach. X-ray absorption spectroscopy is one of the most powerful x-ray techniques providing both local atomic order and electronic structure when coupled with ad-hoc theory. Collecting absorption spectra within few x-ray pulses is possible only in a dispersive setup. We demonstrate ultrafast time-resolved measurements of the LIII-edge x-ray absorption near-edge spectra of irreversibly laser excited Molybdenum using an average of only few x-ray pulses with a signal to noise ratio limited only by the saturation level of the detector. The simplicity of the experimental set-up makes this technique versatile and applicable for a wide range of pump-probe experiments, particularly in the case of non-reversible processes.

  18. Towards simultaneous measurements of electronic and structural properties in ultra-fast x-ray free electron laser absorption spectroscopy experiments

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gaudin, J.; Fourment, C.; Cho, B. I.; Engelhorn, K.; Galtier, E.; Harmand, M.; Leguay, P. M.; Lee, H. J.; Nagler, B.; Nakatsutsumi, M.; et al

    2014-04-17

    The rapidly growing ultrafast science with X-ray lasers unveils atomic scale processes with unprecedented time resolution bringing the so called “molecular movie” within reach. X-ray absorption spectroscopy is one of the most powerful x-ray techniques providing both local atomic order and electronic structure when coupled with ad-hoc theory. Collecting absorption spectra within few x-ray pulses is possible only in a dispersive setup. We demonstrate ultrafast time-resolved measurements of the LIII-edge x-ray absorption near-edge spectra of irreversibly laser excited Molybdenum using an average of only few x-ray pulses with a signal to noise ratio limited only by the saturation level ofmore »the detector. The simplicity of the experimental set-up makes this technique versatile and applicable for a wide range of pump-probe experiments, particularly in the case of non-reversible processes.« less

  19. 3D Imaging of Nickel Oxidation States using Full Field X-ray Absorption Near Edge Structure Nanotomography

    SciTech Connect (OSTI)

    Nelson, George; Harris, William; Izzo, John; Grew, Kyle N.

    2012-01-20

    Reduction-oxidation (redox) cycling of the nickel electrocatalyst phase in the solid oxide fuel cell (SOFC) anode can lead to performance degradation and cell failure. A greater understanding of nickel redox mechanisms at the microstructural level is vital to future SOFC development. Transmission x-ray microscopy (TXM) provides several key techniques for exploring oxidation states within SOFC electrode microstructure. Specifically, x-ray nanotomography and x-ray absorption near edge structure (XANES) spectroscopy have been applied to study samples of varying nickel (Ni) and nickel oxide (NiO) compositions. The imaged samples are treated as mock SOFC anodes containing distinct regions of the materials in question. XANES spectra presented for the individual materials provide a basis for the further processing and analysis of mixed samples. Images of composite samples obtained are segmented, and the distinct nickel and nickel oxide phases are uniquely identified using full field XANES spectroscopy. Applications to SOFC analysis are discussed.

  20. Understanding Sulfur Poisoning and Regeneration of Nickel Biomass Conditioning Catalysts using X-Ray Absorption Spectroscopy

    SciTech Connect (OSTI)

    Yung, M. M.; Cheah, S.; Kuhn, J. N.

    2013-01-01

    The production of biofuels can proceed via a biomass gasification to produce syngas, which can then undergo catalytic conditioning and reforming reactions prior to being sent to a fuel synthesis reactor. Catalysts used for biomass conditioning are plagued by short lifetimes which are a result of, among other things, poisoning. Syngas produced from biomass gasification may contain between 30-300 ppm H2S, depending on the feedstock and gasification conditions, and H2S is a key catalyst poison. In order to overcome catalyst poisoning, either an H2S-tolerant catalyst or an efficient regeneration protocol should be employed. In this study, sulfur K-edge X-ray absorption near edge spectroscopy (XANES) was used to monitor sulfur species on spent catalyst samples and the transformation of these species from sulfides to sulfates during steam and air regeneration on a Ni/Mg/K/Al2O3 catalyst used to condition biomass-derived syngas. Additionally, nickel K-edge EXAFS and XANES are used to examine the state of nickel species on the catalysts. Post-reaction samples showed the presence of sulfides on the H2S-poisoned nickel catalyst and although some gaseous sulfur species were observed to leave the catalyst bed during regeneration, sulfur remained on the catalyst and a transformation from sulfides to sulfates was observed. The subsequent H2 reduction led to a partial reduction of sulfates back to sulfides. A proposed reaction sequence is presented and recommended regeneration strategies are discussed.

  1. Identification of lead chemical form in mine waste materials by X-ray absorption spectroscopy

    SciTech Connect (OSTI)

    Taga, Raijeli L.; Ng, Jack [University of Queensland, National Research Centre for Environmental Toxicology (EnTox), Brisbane, 4108 (Australia); Zheng Jiajia; Huynh, Trang; Noller, Barry [University of Queensland, Centre for Mined Land Rehabilitation, Brisbane, 4072 (Australia); Harris, Hugh H. [School of Chemistry and Physics, University of Adelaide, Adelaide, 5005 (Australia)

    2010-06-23

    X-ray absorption spectroscopy (XAS) provides a direct means for measuring lead chemical forms in complex samples. In this study, XAS was used to identify the presence of plumbojarosite (PbFe{sub 6}(SO{sub 4}){sub 4}(OH){sub 12}) by lead L{sub 3}-edge XANES spectra in mine waste from a small gold mining operation in Fiji. The presence of plumbojarosite in tailings was confirmed by XRD but XANES gave better resolution. The potential for human uptake of Pb from tailings was measured using a physiologically based extract test (PBET), an in-vitro bioaccessibility (BAc) method. The BAc of Pb was 55%. Particle size distribution of tailings indicated that 40% of PM{sub 10} particulates exist which could be a potential risk for respiratory effects via the inhalation route. Food items collected in the proximity of the mine site had lead concentrations which exceed food standard guidelines. Lead within the mining lease exceeded sediment guidelines. The results from this study are used to investigate exposure pathways via ingestion and inhalation for potential risk exposure pathways of Pb in that locality. The highest Pb concentration in soil and tailings was 25,839 mg/kg, exceeding the Australian National Environment Protection Measure (NEPM) soil health investigation levels.

  2. Masked-backlighter technique used to simultaneously image x-ray absorption and x-ray emission from an inertial confinement fusion plasma

    SciTech Connect (OSTI)

    Marshall, F. J., E-mail: fredm@lle.rochester.edu; Radha, P. B. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2014-11-15

    A method to simultaneously image both the absorption and the self-emission of an imploding inertial confinement fusion plasma has been demonstrated on the OMEGA Laser System. The technique involves the use of a high-Z backlighter, half of which is covered with a low-Z material, and a high-speed x-ray framing camera aligned to capture images backlit by this masked backlighter. Two strips of the four-strip framing camera record images backlit by the high-Z portion of the backlighter, while the other two strips record images aligned with the low-Z portion of the backlighter. The emission from the low-Z material is effectively eliminated by a high-Z filter positioned in front of the framing camera, limiting the detected backlighter emission to that of the principal emission line of the high-Z material. As a result, half of the images are of self-emission from the plasma and the other half are of self-emission plus the backlighter. The advantage of this technique is that the self-emission simultaneous with backlighter absorption is independently measured from a nearby direction. The absorption occurs only in the high-Z backlit frames and is either spatially separated from the emission or the self-emission is suppressed by filtering, or by using a backlighter much brighter than the self-emission, or by subtraction. The masked-backlighter technique has been used on the OMEGA Laser System to simultaneously measure the emission profiles and the absorption profiles of polar-driven implosions.

  3. First-Principles Calculation of Principal Hugoniot and K-Shell X-ray Absorption Spectra for Warm Dense KCl

    E-Print Network [OSTI]

    Zhao, Shijun; Kang, Wei; Li, Zi; Zhang, Ping; He, Xian-Tu

    2015-01-01

    Principal Hugoniot and K-shell X-ray absorption spectra of warm dense KCl are calculated using the first-principles molecular dynamics method. Evolution of electronic structures as well as the influence of the approximate description of ionization on pressure (caused by the underestimation of the energy gap between conduction bands and valence bands) in the first-principles method are illustrated by the calculation. Pressure ionization and thermal smearing are shown as the major factors to prevent the deviation of pressure from global accumulation along the Hugoniot. In addition, cancellation between electronic kinetic pressure and virial pressure further reduces the deviation. The calculation of X-ray absorption spectra shows that the band gap of KCl persists after the pressure ionization of the $3p$ electrons of Cl and K taking place at lower energy, which provides a detailed understanding to the evolution of electronic structures of warm dense matter.

  4. Operando X-ray absorption and EPR evidence for a single electron redox process in copper catalysis

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lu, Qingquan; Zhang, Jian; Peng, Pan; Zhang, Guanghui; Huang, Zhiliang; Yi, Hong; Miller, Jeffrey T.; Lei, Aiwen

    2015-05-26

    An unprecedented single electron redox process in copper catalysis is confirmed using operando X-ray absorption and EPR spectroscopies. The oxidation state of the copper species in the interaction between Cu(II) and a sulfinic acid at room temperature, and the accurate characterization of the formed Cu(I) are clearly shown using operando X-ray absorption and EPR evidence. Further investigation of anion effects on Cu(II) discloses that bromine ions can dramatically increase the rate of the redox process. Moreover, it is proven that the sulfinic acids are converted into sulfonyl radicals, which can be trapped by 2-arylacrylic acids and various valuable ?-keto sulfonesmore »are synthesized with good to excellent yields under mild conditions.« less

  5. Cadmium Chemical Form in Mine Waste Materials by X-ray Absorption Spectroscopy

    SciTech Connect (OSTI)

    Diacomanolis, V.; Ng, J. C. [University of Queensland, National Research Centre for Environmental Toxicology, Coopers Plains, QLD, 4008 (Australia); Sadler, R. [School of Public Health, Griffith University, Brisbane, QLD (Australia); Harris, H. H. [School of Chemistry and Physics, University of Adelaide, Adelaide, SA (Australia); Nomura, M. [Photon Factory, Institute of Material Structure Science, Tsukuba (Japan); Noller, B. N. [University of Queensland, Centre For Mined Land Rehabilitation, St Lucia 4072 QLD (Australia)

    2010-06-23

    This study examines the molecular form of cadmium (Cd) present in mine wastes by X-ray Absorption Spectroscopy (XAS; Cd>20 mg/kg) using the K-edge of Cd at the Photon Factory Advanced Ring (PF-AR), NW10A beam line at KEK-Tsukuba-Japan. Mine waste materials and zinc concentrate were analyzed for Cd by ICPMS prior to undertaking XAS (range 21-452 mg/kg). Model compounds (CdO, Cd(OH){sub 2}, CdCO{sub 3}, Cdacetate, CdS, Cdstearate, CdDEDTC) and samples were examined in solid form at 20 K. The XANES spectra showed similar E max values for both model compounds and samples. The EXAFS showed that Cd-S in CdS, gives a flatter spectrum in the extended region compared to Cd-O found with CdCO{sub 3}, CdO and Cd Stearate. Linear combination fitting with model Cd compounds did not give clear assignments of composition, indicating that more detailed EXAFS spectra is required as mineral forms containing Cd were present rather than simple Cd compounds such as CdCO{sub 3}. The Cd bond for a single shell model in mine waste sample matrices appears to be either Cd-O or Cd-S, or a combination of both. Comparison of molecular data from the XAS studies with bioaccessibility data giving a prediction of bioavailability for mine waste materials provides useful information about the significance of the cadmium form as a contaminant for health risk assessment purposes.

  6. X-Ray Absorption Studies of Vanadium-Containing Metal Oxide Nanocrystals

    SciTech Connect (OSTI)

    Hohn, Keith, L.

    2006-01-09

    Metal oxide nanocrystals offer significant potential for use as catalysts or catalyst supports due to their high surface areas and unique chemical properties that result from the high number of exposed corners and edges. However, little is known about the catalytic activity of these materials, especially as oxidation catalysts. This research focused on the preparation, characterization and use of vanadium-containing nanocrystals as selective oxidation catalysts. Three vanadium-containing nanocrystals were prepared using a modified sol-gel procedure: V/MgO, V/SiO2, and vanadium phosphate (VPO). These represent active oxidation catalysts for a number of industrially relevant reactions. The catalysts were characterized by x-ray diffraction and Raman, UV-VIS, infrared and x-ray absorption spectroscopies with the goal of determining the primary structural and chemical differences between nanocrystals and microcrystals. The catalytic activity of these catalysts was also studied in oxidative dehydrogenation of butane and methanol oxidation to formaldehyde. V/MgO nanocrystals were investigated for activity in oxidative dehydrogenation of butane and compared to conventional V/MgO catalysts. Characterization of V/MgO catalysts using Raman spectroscopy and x-ray absorption spectroscopy showed that both types of catalysts contained magnesium orthovanadate at vanadium loadings below 15 weight%, but above that loading, magnesium pyrovanadate may have been present. In general, MgO nanocrystals had roughly half the crystal size and double the surface area of the conventional MgO. In oxidative dehydrogenation of butane, nanocrystalline V/MgO gave higher selectivity to butene than conventional V/MgO at the same conversion. This difference was attributed to differences in vanadium domain size resulting from the higher surface areas of the nanocrystalline support, since characterization suggested that similar vanadium phases were present on both types of catalysts. Experiments in methanol oxidation were used to probe the chemical differences between sol-gel prepared and conventionally prepared metal oxides. Both V/MgO and V/SiO2 were studied. For both catalysts, similar product selectivities were noted for either preparation method, suggesting similar acid/base and redox properties for the catalysts. At lower weight loadings (<5%), activity was also similar, but at higher weight loadings the sol-gel prepared catalysts were more active. This was attributed to the greater dispersion of vanadium on sol-gel prepared catalysts, and it was suggested that small vanadium oxide domains were more active in methanol oxidation than polymeric and bulk domains. A novel sol-gel method was developed for preparation of VPO catalysts, which are used industrially in butane oxidation to maleic anhydride. In this method vanadium (V) triisopropoxide was reacted with orthophosphoric acid in THF to form a gel. Drying this gel under air resulted in an intercalated VOPO4 compound, where solvent molecules were trapped between layers of the vanadium phosphate compound. Higher surface areas could be achieved by drying this gel at high pressure in an autoclave. The amount of solvent (THF) placed in the autoclave was important in this process. Low amounts of solvent led to a lower surface area, as the solvent evaporated before reaching the critical point and collapsed the gel's pores. In addition, vanadium reduction occurred in the autoclave due to reaction of isopropanol with the vanadium phosphate. Higher amounts of THF reduced the concentration of isopropanol, leading to less reduction. Surfaces areas in excess of 100 m2/g were achieved with this method, and the product was confirmed through XPS and IR to be VOHPO4*0.5H2O, the common precursor for industrial VPO catalysts. Furthermore, this product displayed a platelet morphology, which is desirable for butane oxidation. Further work showed that this material could be transformed to (VO)2P2O7 (the industrial catalyst for butane oxidation to maleic anhydride) by heating under nitrogen without losing much surface are

  7. Background proportional enhancement of the extended fine structure in nonresonant inelastic x-ray scattering

    E-Print Network [OSTI]

    Seidler, Gerald T.

    Background proportional enhancement of the extended fine structure in nonresonant inelastic x is proportional to the strong q-dependent evolution in shape and magnitude of the atomic background. This en

  8. Speciation and Release Kinetics of Cadmium in Alkali and Acidic Paddy Soils: Application of X-Ray Absorption Spectroscopy Monday, November 2, 2009: 10:30 AM

    E-Print Network [OSTI]

    Sparks, Donald L.

    Speciation and Release Kinetics of Cadmium in Alkali and Acidic Paddy Soils: Application of X under alkali and acidic conditions. X-ray absorption spectroscopy (XAS) was used to investigate Cd

  9. Quantum chemistry studies of the O K-edge X-ray absorption in WO3 and AWO3

    E-Print Network [OSTI]

    Bocharov, Dmitry; Purans, Juris; Zhukovskii, Yuri; 10.1117/12.815297

    2010-01-01

    In this work we present an interpretation of experimental O K-edge x-ray absorption near edge structure (XANES) in perovskite-type WO3 and AWO3 compounds (A = H and Na) using three different first principles approaches: (i) full-multiple-scattering (FMS) formalism (the real-space FEFF code), (ii) hybrid density functional theory (DFT) method with partial incorporation of exact Hartree-Fock exchange using formalism of the linear combination of atomic orbitals (LCAO) as implemented in the CRYSTAL code; (iii) plane-wave DFT method using formalism of the projector-augmented waves (PAW) as implemented in the VASP code.

  10. High energy resolution five-crystal spectrometer for high quality fluorescence and absorption measurements on an x-ray absorption spectroscopy beamline

    SciTech Connect (OSTI)

    Llorens, Isabelle; Lahera, Eric; Delnet, William; Proux, Olivier; Dermigny, Quentin; Gelebart, Frederic; Morand, Marc; Shukla, Abhay; Bardou, Nathalie; Ulrich, Olivier; and others

    2012-06-15

    Fluorescence detection is classically achieved with a solid state detector (SSD) on x-ray absorption spectroscopy (XAS) beamlines. This kind of detection however presents some limitations related to the limited energy resolution and saturation. Crystal analyzer spectrometers (CAS) based on a Johann-type geometry have been developed to overcome these limitations. We have tested and installed such a system on the BM30B/CRG-FAME XAS beamline at the ESRF dedicated to the structural investigation of very dilute systems in environmental, material and biological sciences. The spectrometer has been designed to be a mobile device for easy integration in multi-purpose hard x-ray synchrotron beamlines or even with a laboratory x-ray source. The CAS allows to collect x-ray photons from a large solid angle with five spherically bent crystals. It will cover a large energy range allowing to probe fluorescence lines characteristic of all the elements from Ca (Z = 20) to U (Z = 92). It provides an energy resolution of 1-2 eV. XAS spectroscopy is the main application of this device even if other spectroscopic techniques (RIXS, XES, XRS, etc.) can be also achieved with it. The performances of the CAS are illustrated by two experiments that are difficult or impossible to perform with SSD and the complementarity of the CAS vs SSD detectors is discussed.

  11. Local structure and polarization resistance of Ce doped SrMnO{sub 3} using extended x-ray fine structure analysis

    SciTech Connect (OSTI)

    Ryu, Jiseung; Lee, Heesoo, E-mail: heesoo@pusan.ac.kr [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

    2014-09-15

    Changes to the local structure of Sr and Mn atoms in Sr{sub 1?x}Ce{sub x}MnO{sub 3} (SCM) according to increasing Ce content and the effect of the structural change on the polarization resistance of SCM were investigated. The reduction of manganese was confirmed by the absorption edge shift of the Mn K-edge toward lower energies. The noise of oscillation in extended X-ray absorption fine structure k{sup 3}? data at Mn K-edge reveals the distortion of the local structure of Mn atoms, and the peak that indicates the bonding length of Mn-O, Sr/Ce, and -Mn decreased with the addition of Ce content in Fourier transformations of the Mn K-edge. The distortion of the local structure at Mn atoms was affected by the reduced manganese ions having larger ionic radii than Mn{sup 4+}. Meanwhile, few distortions of local atomic structures of Sr atoms occurred, and the average nearest neighboring distances of Sr-O and Sr-Mn are ?2.13?Å and ?2.95?Å, respectively. The average bonding lengths of the Ce-O and Ce-Mn increased because the ionic radius of substituted Ce ion with 12 coordination number is smaller than that of Sr ion, which leads the reduction of Mn ions and the distortion of local structure at the substituted A-site. Therefore, we reasoned that the distortion of the local atomic structure at Mn atoms in MnO{sub 6} and Ce atoms in A-site is one of the causes for interrupting oxygen ion transfers as a geometric factor, which results in an increase in the polarization resistance of SCM within the Ce composition range from 10?mol.?% to 30?mol.?%.

  12. Structure of epitaxial (Fe,N) codoped rutile TiO2 thin films by x-ray absorption

    SciTech Connect (OSTI)

    Kaspar, Tiffany C.; Ney, A.; Mangham, Andrew N.; Heald, Steve M.; Joly, Yves; Ney, V.; Wilhelm, F.; Rogalev, A.; Yakou, Flora; Chambers, Scott A.

    2012-07-23

    Homoepitaxial thin films of Fe:TiO2 and (Fe,N):TiO2 were deposited on rutile(110) by molecular beam epitaxy. X-ray absorption near edge spectroscopy (XANES) spectra were collected at the Ti L-edge, Fe L-edge, O K-edge, N K-edge, and Ti K-edge. No evidence of structural disorder associated with a high concentration of oxygen vacancies is observed. Substitution of Fe for Ti could not be confirmed, although secondary phase Fe2O3 and metallic Fe can be ruled out. The similarity of the N K-edge spectra to O, and the presence of a strong x-ray linear dichroism (XLD) signal for the N K-edge, indicates that N is substitutional for O in the rutile lattice, and is not present as a secondary phase such as TiN. Simulations of the XANES spectra qualitatively confirm substitution, although N appears to be present in more than one local environment. Neither Fe:TiO2 nor (Fe,N):TiO2 exhibit intrinsic room temperature ferromagnetism, despite the presence of mixed valence Fe(II)/Fe(III) in the reduced (Fe,N):TiO2 film.

  13. Electronic structure of lanthanum copper oxychalcogenides LaCuOCh (Ch=S, Se, Te) by X-ray photoelectron and absorption spectroscopy

    SciTech Connect (OSTI)

    Rudyk, Brent W.; Blanchard, Peter E.R.; Cavell, Ronald G. [Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada); Mar, Arthur, E-mail: arthur.mar@ualberta.ca [Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada)

    2011-07-15

    X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge spectroscopy (XANES) have been applied to examine the electronic structures of lanthanum copper oxychalcogenides LaCuOCh (Ch=S, Se, Te), whose structure has been conventionally viewed as consisting of nominally isolated [LaO] and [CuCh] layers. However, there is evidence for weak La-Ch interactions between these layers, as seen in small changes in the satellite intensity of the La 3d XPS spectra as the chalcogen is changed and as supported by band structure calculations. The O 1s and Cu 2p XPS spectra are insensitive to chalcogen substitution. Lineshapes in the Cu 2p XPS spectra and fine-structure in the Cu L- and M-edge XANES spectra support the presence of Cu{sup +} species. The Ch XPS spectra show negative BE shifts relative to the elemental chalcogen, indicative of anionic species; these shifts correlate well with greater difference in electronegativity between the Cu and Ch atoms, provided that an intermediate electronegativity is chosen for Se. - Graphical abstract: The presence of anionic chalcogen atoms in LaCuOCh is supported by the Ch binding energies, which undergo negative shifts proportional to the polarity of the Cu-Ch bonds. Highlights: > La 3d XPS confirms La-Ch interlayer interactions between [LaO] and [CuCh] layers. > O 1s and Cu 2p XPS are insensitive to chalcogen substitution. > Cu XANES spectra support the presence of Cu{sup +} species. > Negative shifts in Ch binding energies imply anionic chalcogen atoms.

  14. Nitrogen K-edge x-ray absorption near edge structure of pyrimidine-containing nucleotides in aqueous solution

    SciTech Connect (OSTI)

    Shimada, Hiroyuki Minami, Hirotake; Okuizumi, Naoto; Sakuma, Ichiro; Ukai, Masatoshi; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro; Saitoh, Yuji

    2015-05-07

    X-ray absorption near edge structure (XANES) was measured at energies around the N K-edge of the pyrimidine-containing nucleotides, cytidine 5?-monophosphate (CMP), 2?-deoxythymidine 5?-monophosphate (dTMP), and uridine 5?-monophosphate (UMP), in aqueous solutions and in dried films under various pH conditions. The features of resonant excitations below the N K-edge in the XANES spectra for CMP, dTMP, and UMP changed depending on the pH of the solutions. The spectral change thus observed is systematically explained by the chemical shift of the core-levels of N atoms in the nucleobase moieties caused by structural changes due to protonation or deprotonation at different proton concentrations. This interpretation is supported by the results of theoretical calculations using density functional theory for the corresponding nucleobases in the neutral and protonated or deprotonated forms.

  15. Revisiting the total ion yield x-ray absorption spectra of liquid water microjets

    E-Print Network [OSTI]

    Cappa, Chris D.

    2008-01-01

    the “free” –OH bond. The water molecule of interest is shownAbsorption Spectra of Liquid Water Microjets Christopher D.spectrum (XAS) of liquid water by Wilson et al. [J. Phys.

  16. MAGNETOHYDRODYNAMIC MODELING OF THE ACCRETION SHOCKS IN CLASSICAL T TAURI STARS: THE ROLE OF LOCAL ABSORPTION IN THE X-RAY EMISSION

    SciTech Connect (OSTI)

    Bonito, R.; Argiroffi, C.; Peres, G. [Dip. di Fisica e Chimica, Università di Palermo, P.zza del Parlamento 1, I-90134 Palermo (Italy); Orlando, S.; Miceli, M.; Ibgui, L. [INAF-Osservatorio Astronomico di Palermo, P.zza del Parlamento 1, I-90134 Palermo (Italy); Matsakos, T. [Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 (United States); Stehle, C., E-mail: sbonito@astropa.unipa.it [LERMA, Observatoire de Paris, Université Pierre et Marie Curie, Ecole Normale Superieure, Universite Cergy-Pontoise, CNRS, F-75014 Paris (France)

    2014-11-10

    We investigate the properties of X-ray emission from accretion shocks in classical T Tauri stars (CTTSs), generated where the infalling material impacts the stellar surface. Both observations and models of the accretion process reveal several aspects that are still unclear: the observed X-ray luminosity in accretion shocks is below the predicted value, and the density versus temperature structure of the shocked plasma, with increasing densities at higher temperature, deduced from the observations, is at odds with that proposed in the current picture of accretion shocks. To address these open issues, we investigate whether a correct treatment of the local absorption by the surrounding medium is crucial to explain the observations. To this end, we describe the impact of an accretion stream on a CTTS by considering a magnetohydrodynamic model. From the model results, we synthesize the X-ray emission from the accretion shock by producing maps and spectra. We perform density and temperature diagnostics on the synthetic spectra, and we directly compare the results with observations. Our model shows that the X-ray fluxes inferred from the emerging spectra are lower than expected because of the complex local absorption by the optically thick material of the chromosphere and of the unperturbed stream. Moreover, our model, including the effects of local absorption, explains in a natural way the apparently puzzling pattern of density versus temperature observed in the X-ray emission from accretion shocks.

  17. Direct speciation analysis of arsenic in sub-cellular compartments using micro-X-ray absorption spectroscopy

    SciTech Connect (OSTI)

    Bacquart, Thomas; Deves, Guillaume; Ortega, Richard

    2010-07-15

    Identification of arsenic chemical species at a sub-cellular level is a key to understanding the mechanisms involved in arsenic toxicology and antitumor pharmacology. When performed with a microbeam, X-ray absorption near-edge structure ({mu}-XANES) enables the direct speciation analysis of arsenic in sub-cellular compartments avoiding cell fractionation and other preparation steps that might modify the chemical species. This methodology couples tracking of cellular organelles in a single cell by confocal or epifluorescence microscopy with local analysis of chemical species by {mu}-XANES. Here we report the results obtained with a {mu}-XANES experimental setup based on Kirkpatrick-Baez X-ray focusing optics that maintains high flux of incoming radiation (>10{sup 11} ph/s) at micrometric spatial resolution (1.5x4.0 {mu}m{sup 2}). This original experimental setup enabled the direct speciation analysis of arsenic in sub-cellular organelles with a 10{sup -15} g detection limit. {mu}-XANES shows that inorganic arsenite, As(OH){sub 3}, is the main form of arsenic in the cytosol, nucleus, and mitochondrial network of cultured cancer cells exposed to As{sub 2}O{sub 3}. On the other hand, a predominance of As(III) species is observed in HepG2 cells exposed to As(OH){sub 3} with, in some cases, oxidation to a pentavalent form in nuclear structures of HepG2 cells. The observation of intra-nuclear mixed redox states suggests an inter-individual variability in a cell population that can only be evidenced with direct sub-cellular speciation analysis.

  18. THE STRUCTURAL CHEMISTRY OF MOLYBDENUM IN MODEL HIGH LEVEL NUCLEAR WASTE GLASSES, INVESTIGATED BY MO K-EDGE X-RAY ABSORPTION

    E-Print Network [OSTI]

    Sheffield, University of

    THE STRUCTURAL CHEMISTRY OF MOLYBDENUM IN MODEL HIGH LEVEL NUCLEAR WASTE GLASSES, INVESTIGATED of molybdenum in model UK high level nuclear waste glasses was investigated by X-ray Absorption Spectroscopy (XAS). Molybdenum K-edge XAS data were acquired from several inactive simulant high level nuclear waste

  19. X-ray absorption spectroscopy of LiBF 4 in propylene carbonate. A model lithium ion battery electrolyte

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Smith, Jacob W.; Lam, Royce K.; Sheardy, Alex T.; Shih, Orion; Rizzuto, Anthony M.; Borodin, Oleg; Harris, Stephen J.; Prendergast, David; Saykally, Richard J.

    2014-08-20

    Since their introduction into the commercial marketplace in 1991, lithium ion batteries have become increasingly ubiquitous in portable technology. Nevertheless, improvements to existing battery technology are necessary to expand their utility for larger-scale applications, such as electric vehicles. Advances may be realized from improvements to the liquid electrolyte; however, current understanding of the liquid structure and properties remains incomplete. X-ray absorption spectroscopy of solutions of LiBF4 in propylene carbonate (PC), interpreted using first-principles electronic structure calculations within the eXcited electron and Core Hole (XCH) approximation, yields new insight into the solvation structure of the Li+ ion in this model electrolyte.more »By generating linear combinations of the computed spectra of Li+-associating and free PC molecules and comparing to the experimental spectrum, we find a Li+–solvent interaction number of 4.5. This result suggests that computational models of lithium ion battery electrolytes should move beyond tetrahedral coordination structures.« less

  20. Particle size effect of hydride formation and surface hydrogen absorption of nanosized palladium catalysts : L{sub 3} edge vs K edge x-ray absorption spectroscopy.

    SciTech Connect (OSTI)

    Tew, M. W.; Miller, J. T.; van Bokhoven, J. A.

    2009-08-01

    The particle size effect on the formation of palladium hydride and on surface hydrogen adsorption was studied at room temperature using in situ X-ray absorption spectroscopy at the Pd K and L{sub 3} edges. Hydride formation was indirectly observed by lattice expansion in Pd K edge XANES spectra and by EXAFS analysis. Hydride formation was directly detected in the L{sub 3} edge spectra. A characteristic spectral feature caused by the formation of a Pd-H antibonding state showed strong particle size dependence. The L{sub 3} edge spectra were reproduced using full multiple scattering analysis and density of state calculations, and the contributions of bulk absorbed and surface hydrogen to the XANES spectra could be distinguished. The ratio of hydrogen on the surface versus that in the bulk increased with decreasing particle size, and smaller particles dissolved less hydrogen.

  1. Experimental and Theoretical Comparison of the O K-Edge Nonresonant Inelastic X-ray Scattering and X-ray Absorption Spectra of NaReO[subscript 4

    SciTech Connect (OSTI)

    Bradley, Joseph A.; Yang, Ping; Batista, Enrique R.; Boland, Kevin S.; Burns, Carol J.; Clark, David L.; Conradson, Steven D.; Kozimor, Stosh A.; Martin, Richard L.; Seidler, Gerald T.; Scott, Brian L.; Shuh, David K.; Tyliszczak, Tolek; Wilkerson, Marianne P.; Wolfsberg, Laura E. (PNNL); (UWASH); (LBNL); (LANL)

    2010-12-07

    Accurate X-ray absorption spectra (XAS) of first row atoms, e.g., O, are notoriously difficult to obtain due to the extreme sensitivity of the measurement to surface contamination, self-absorption, and saturation affects. Herein, we describe a comprehensive approach for determining reliable O K-edge XAS data for ReO{sub 4}{sup 1-} and provide methodology for obtaining trustworthy and quantitative data on nonconducting molecular systems, even in the presence of surface contamination. This involves comparing spectra measured by nonresonant inelastic X-ray scattering (NRIXS), a bulk-sensitive technique that is not prone to X-ray self-absorption and provides exact peak intensities, with XAS spectra obtained by three different detection modes, namely total electron yield (TEY), fluorescence yield (FY), and scanning transmission X-ray microscopy (STXM). For ReO{sub 4}{sup 1-}, TEY measurements were heavily influenced by surface contamination, while the FY and STXM data agree well with the bulk NRIXS analysis. These spectra all showed two intense pre-edge features indicative of the covalent interaction between the Re 5d and O 2p orbitals. Density functional theory calculations were used to assign these two peaks as O 1s excitations to the e and t{sub 2} molecular orbitals that result from Re 5d and O 2p covalent mixing in T{sub d} symmetry. Electronic structure calculations were used to determine the amount of O 2p character (%) in these molecular orbitals. Time dependent-density functional theory (TD-DFT) was also used to calculate the energies and intensities of the pre-edge transitions. Overall, under these experimental conditions, this analysis suggests that NRIXS, STXM, and FY operate cooperatively, providing a sound basis for validation of bulk-like excitation spectra and, in combination with electronic structure calculations, suggest that NaReO{sub 4} may serve as a well-defined O K-edge energy and intensity standard for future O K-edge XAS studies.

  2. Experimental and Theoretical Comparison of the O K-Edge Non-Resonant Inelastic X-ray Scattering and X-ray Absorption Spectra of NaReO4

    SciTech Connect (OSTI)

    Bradley, Joseph A.; Yang, Ping; Batista, Enrique R.; Boland, Kevin S.; Burns, Carol J.; Clark, David L.; Conradson, Steven D.; Kozimor, Stosh A.; Martin, Richard L.; Seidler, Gerald T.; Scott, Brian L.; Shuh, David K.; Tyliszczak, T.; Wilkerson, Marianne P.; Wolfsberg, Laura E.

    2010-09-14

    Accurate X-ray absorption spectra (XAS) of first row atoms, e.g. O, are notoriously difficult to obtain due to the extreme sensitivity of the measurement to surface contamination, self-absorption, and saturation effects. Herein, we describe a comprehensive approach for determining reliable O K-edge XAS data for ReO41- and provide methodology for obtaining trustworthy and quantitative data on non-conducting molecular systems, even in the presence of surface contamination. This involves comparing spectra measured by non-resonant inelastic X-ray scattering (NRIXS), a bulk-sensitive technique that is not prone to X-ray self-absorption and provides exact peak intensities, with XAS spectra obtained by three different detection modes, namely total electron yield (TEY), fluorescence yield (FY), and scanning transmission X-ray microscopy (STXM). For ReO41-, TEY measurements were heavily influenced by surface contamination, while the FY and STXM data agree well with the bulk NRIXS analysis. These spectra all showed two intense pre-edge features indicative of the covalent interaction between the Re 5d and O 2p orbitals. Time dependent density functional theory calculations were used to assign these two peaks as O 1s excitations to the e and t2 molecular orbitals that result from Re 5d and O 2p covalent mixing in Td symmetry. Electronic structure calculations were used to determine the amount of O 2p character (%) in these molecular orbitals. Time-dependent density functional theory (TD-DFT) was also used to calculate the energies and intensities of the pre-edge transitions. Overall, under these experimental conditions, this analysis suggests that NRIXS, STXM, and FY operate cooperatively, providing a sound basis for validation of bulk-like excitation spectra and, in combination with electronic structure calculations, suggest that NaReO4 may serve as a well-defined O K-edge energy and intensity standard for future O K edge XAS studies.

  3. In situ monitoring of the electrochemical absorption of deuterium into palladium by x-ray diffraction using synchrotron-wiggler radiation

    SciTech Connect (OSTI)

    Dominguez, D.D.; Hagans, P.L.; Skelton, E.F.; Qadri, S.B.; Nagel, D.J.

    1998-12-31

    With low energy x-rays, such as those from a Cu x-ray tube, only the outer few microns of a metallic sample can be probed. This low penetrating power prohibits structural studies from being carried out on the interior of an electrode in an electrochemical cell because of absorption by the cell material, electrodes and the electrolyte. The work described in this paper circumvents this problem by utilizing high energy, high brightness x-rays produced on the superconducting wiggler beam line, X-17C, at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The penetrating power of the higher energy x-rays allowed Pd diffraction spectra to be obtained in-situ on a 1 mm diameter Pd wire cathode during electrolysis of heavy water. Moreover, the beam (28 x 28 {micro}m in cross-section) allowed diffraction spectra to be acquired as a function of distance across the sample. Spectra were recorded in 50 {micro}m steps from the edge of the Pd wire to its core. This was done at 2 minute intervals as a function of electrolysis time. The {alpha}-{beta} phase transition induced in the Pd while deuterium was electrochemically absorbed was observed by monitoring the Pd-(422) diffraction peaks. Results allowed the diffusion rate and the diffusivity of deuterium atoms in the Pd wire to be determined. Other features of the structural changes associated with the absorption of deuterium into Pd are reported.

  4. RAPID COMMUNICATION Near-Edge X-Ray Absorption Fine Structure (NEXAFS) Microscopy of a

    E-Print Network [OSTI]

    of a Polycarbonate/Poly(acrylonitrile/butadiene/styrene) Blend C. C. SLOOP,1 * H. ADE,2 R. E. FORNES,2 R. D. GILBERT; revised 11 December 2000; accepted 20 December 2000 Published online 00 Month 2001 Keywords: polycarbonate/acrylonitrile­butadiene called PC/acrylonitrile­butadiene­styrene (ABS) blends, are complex mixtures. The ABS component consists

  5. In Situ Grazing-Incidence Extended X-ray Absorption Fine Structure Study of

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journal Article)lasers(Journal Article)CurvesAnodic Materials inSciTech Connect

  6. An x-ray absorption spectroscopic study of the electronic structure and bonding of rare-earth orthoferrites

    SciTech Connect (OSTI)

    Hayes, J.R.; Grosvenor, A.P. (Saskatchewan)

    2011-11-07

    Rare-earth orthoferrites, REFeO{sub 3} (RE=rare earth; Y), are tremendously adaptable compounds that are being investigated for use in a wide variety of applications including gas sensors, vehicle catalytic converters, and solid-oxide fuel cells. They also exhibit interesting magnetic properties such as high-temperature antiferromagnetism, making them useful for data storage applications. The compounds adopt a distorted perovskite-type structure where the tilt angle of the octahedra increases (Fe-O-Fe bond angle decreases) as the size of the rare-earth atom decreases. Despite intensive study of the physical properties of these compounds, very few studies have investigated how the bonding and electronic structure of these systems change with substitution of the RE. X-ray absorption near-edge spectroscopy (XANES) is a technique well-suited for such a study, and, in view of this, Fe L-, Fe K- and O K-edge spectra from a series of REFeO{sub 3} compounds (RE=La, Pr, Nd, Sm, Eu, Gd, Ho, Yb, Y) have been collected, and are presented here. Fe L-edge spectra show that Fe is octahedrally coordinated and that the Fe-centered octahedra do not appear to distort with changes in the identity of the RE. The Fe K-edge spectra contain an intersite hybrid peak, which is an ill-studied feature that is attributed to non-local transitions of 1s electrons to 3d states on the next-nearest-neighbor atom that are hybridized with 4p states on the absorbing atom through O 2p states. In this study, it is shown that the intensity of this feature is strongly dependent on the Fe-O-Fe bond angle; the lower the Fe-O-Fe bond angle, the less intense the intersite hybrid peak is.

  7. High resolution absorption spectroscopy of exploding wire plasmas using an x-pinch x-ray source and spherically bent crystal

    SciTech Connect (OSTI)

    Knapp, P. F.; Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.; Hansen, S. B.

    2011-06-15

    We present here the use of absorption spectroscopy of the continuum radiation from x-pinch-produced point x-ray sources as a diagnostic to investigate the properties of aluminum plasmas created by pulsed power machines. This technique is being developed to determine the charge state, temperature, and density as a function of time and space under conditions that are inaccessible to x-ray emission spectroscopic diagnostics. The apparatus and its characterization are described, and the spectrometer dispersion, magnification, and resolution are calculated and compared with experimental results. Spectral resolution of about 5000 and spatial resolution of about 20 {mu}m are demonstrated. This spectral resolution is the highest available to date in an absorption experiment. The beneficial properties of the x-pinch x-ray source as the backlighter for this diagnostic are the small source size (<5 {mu}m), smooth continuum radiation, and short pulse duration (<0.1 ns). Results from a closely spaced (1 mm) exploding wire pair are shown and the general features are discussed.

  8. A facile gel-combustion route for fine particle synthesis of spinel ferrichromite: X-ray and Mössbauer study on effect of Mg and Ni content

    SciTech Connect (OSTI)

    Vader, V.T.; Achary, S.N.; Meena, S.S.

    2014-02-01

    Highlights: • A novel and facile synthesis route. • Transformation of system from random to inverse spinel. • Appearance of superparamagnetism phase. - Abstract: A novel nitrate–citrate gel combustion route was used to prepare fine particle of a series Mg{sub 1?x}Ni{sub x}FeCrO{sub 4} (0.0 ? x ? 1.0) and its structural properties were investigated. The in situ oxidizing environment provided by the nitrate ions in the gel increases the rate of oxidation and lowers the decomposition temperature of component. All the samples after sintering were characterized at room temperature by X-ray diffraction (XRD) method and Mössbauer spectroscopy techniques. The X-ray and Mössbauer studies confirmed the single phase cubic spinel structure with all Fe ions in 3+ charge state. XRD and Mössbauer studies revealed that the samples of x = 0.0, and 0.2 are random spinel and show rather broad lines, while x = 0.4–1.0 are inverse spinel.

  9. X-ray Absorption Measurements on Nickel Cathode of Sodium-beta Alumina batteries: Fe-Ni-CI Chemical Associations

    SciTech Connect (OSTI)

    Bowden, Mark E.; Alvine, Kyle J.; Fulton, John L.; Lemmon, John P.; Lu, Xiaochuan; Webb-Robertson, Bobbie-Jo M.; Heald, Steve M.; Balasubramanian, Mahalingam; Mortensen, Devon R.; Seidler, Gerald T.; Hess, Nancy J.

    2014-02-01

    Sections of Na-Al-NiCl2 cathodes from sodium-beta alumina ZEBRA batteries have been characterized with X-ray fluorescence mapping, and XANES measurements to probe the microstructure, elemental correlation, and chemical speciation after voltage cycling. Cycling was performed under identical load conditions at either 240 or 280 °C operating temperature and subsequently quenched in either the charged or discharged state. X-ray fluorescence mapping and XANES measurements were made adjacent to the current collector and ?"-Al2O3 solid electrolyte interfaces to detect possible gradients in chemical properties across the cathode. An FeS additive, introduced during battery synthesis, was found to be present as either Fe metal or an Fe(II) chloride in all cathode samples. X-ray fluorescence mapping reveals an operating temperature and charge-state dependent spatial correlation between Fe, Ni, and Cl concentration. XANES measurements indicate that both Ni and Fe are chemically reactive and shift between metallic and chloride phases in the charged and discharged states, respectively. However the percentage of chemically active Ni and Fe is significantly less in the cell operated at lower temperature. Additionally, the cathode appeared chemically homogeneous at the scale of our X-ray measurements.

  10. X-ray diffraction and EXAFS analysis of materials for lithium-based rechargeable batteries

    SciTech Connect (OSTI)

    Sharkov, M. D., E-mail: mischar@mail.ioffe.ru; Boiko, M. E.; Bobyl, A. V.; Ershenko, E. M.; Terukov, E. I. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Zubavichus, Y. V. [National Research Centre “Kurchatov Institute” (Russian Federation)

    2013-12-15

    Lithium iron phosphate LiFePO{sub 4} (triphylite) and lithium titanate Li{sub 4}Ti{sub 5}O{sub 12} are used as components of a number of active materials in modern rechargeable batteries. Samples of these materials are studied by X-ray diffraction and extended X-ray absorption fine structure (EXAFS) spectroscopy. Hypotheses about the phase composition of the analyzed samples are formulated.

  11. In situ soft X-ray absorption spectroscopy investigation of electrochemical corrosion of copper in aqueous NaHCO3 solution

    SciTech Connect (OSTI)

    Jiang, Peng; Chen, Jeng-Lung; Borondics, Ferenc; Glans, Per-Anders; West, Mark W.; Chang, Ching-Lin; Salmeron, Miquel; Guo, Jinghua

    2010-03-31

    A novel electrochemical setup has been developed for soft x-ray absorption studies of the electronic structure of electrode materials during electrochemical cycling. In this communication we illustrate the operation of the cell with a study of the corrosion behavior of copper in aqueous NaHCO3 solution via the electrochemically induced changes of its electronic structure. This development opens the way for in situ investigations of electrochemical processes, photovoltaics, batteries, fuel cells, water splitting, corrosion, electrodeposition, and a variety of important biological processes.

  12. Nitrogen K-edge X-ray absorption near edge structure (XANES) spectra of purine-containing nucleotides in aqueous solution

    SciTech Connect (OSTI)

    Shimada, Hiroyuki; Fukao, Taishi; Minami, Hirotake; Ukai, Masatoshi; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro; Saitoh, Yuji

    2014-08-07

    The N K-edge X-ray absorption near edge structure (XANES) spectra of the purine-containing nucleotide, guanosine 5{sup ?}-monophosphate (GMP), in aqueous solution are measured under various pH conditions. The spectra show characteristic peaks, which originate from resonant excitations of N 1s electrons to ?* orbitals inside the guanine moiety of GMP. The relative intensities of these peaks depend on the pH values of the solution. The pH dependence is explained by the core-level shift of N atoms at specific sites caused by protonation and deprotonation. The experimental spectra are compared with theoretical spectra calculated by using density functional theory for GMP and the other purine-containing nucleotides, adenosine 5{sup ?}-monophosphate, and adenosine 5{sup ?}-triphosphate. The N K-edge XANES spectra for all of these nucleotides are classified by the numbers of N atoms with particular chemical bonding characteristics in the purine moiety.

  13. Molecular orientation in soft matter thin films studied by resonant soft x-ray reflectivity

    SciTech Connect (OSTI)

    Mezger, Markus; Jerome, Blandine; Kortright, Jeffrey B; Valvidares, Manuel; Gullikson, Eric M; Giglia, Angelo; Mahne, Nicola; Nannarone, Stefano

    2011-04-05

    We present a technique to study depth profiles of molecular orientation in soft matter thin films with nanometer resolution. The method is based on dichroism in resonant soft x-ray reflectivity using linear s and p polarization. It combines the chemical sensitivity of near-edge x-ray absorption fine structure spectroscopy to specific molecular bonds and their orientation relative to the polarization of the incident beam with the precise depth profiling capability of x-ray reflectivity. We demonstrate these capabilities on side chain liquid crystalline polymer thin films with soft x-ray reflectivity data at the carbon K edge. Optical constants of the anisotropic refractive index ellipsoid were obtained from a quantitative analysis using the Berreman formalism. For films up to 50 nm thickness we find that the degree of orientation of the long axis exhibits no depth variation and is independent of the film thickness.

  14. Molecular orientation in soft matter thin films studied by resonant soft X-ray reflectivity

    SciTech Connect (OSTI)

    Mezger, Markus; Jerome, Blandine; Kortright, Jeffrey B.; Valvidares, Manuel; Gullikson, Eric; Giglia, Angelo; Mahne, Nicola; Nannarone, Stefano

    2011-01-12

    We present a technique to study depth profiles of molecular orientation in soft matter thin films with nanometer resolution. The method is based on dichroism in resonant soft X-ray reflectivity using linear s- and p-polarization. It combines the chemical sensitivity of Near-Edge X-ray Absorption Fine Structure spectroscopy to specific molecular bonds and their orientation relative to the polarization of the incident beam with the precise depth profiling capability of X-ray reflectivity. We demonstrate these capabilities on side chain liquid crystalline polymer thin films with soft X-ray reflectivity data at the carbon K edge. Optical constants of the anisotropic refractive index ellipsoid were obtained from a quantitative analysis using the Berreman formalism. For films up to 50 nm thickness we find that the degree of orientation of the long axis exhibits no depth variation and isindependent of the film thickness.

  15. Influence of structural disorder on soft x-ray optical behavior of NbC thin films

    SciTech Connect (OSTI)

    Singh, Amol E-mail: rrcat.amol@gmail.com; Modi, Mohammed H.; Sinha, A. K.; Lodha, G. S.; Rajput, Parasmani

    2015-05-07

    Structural and chemical properties of compound materials are modified, when thin films are formed from bulk materials. To understand these changes, a study was pursued on niobium carbide (NbC) thin films of different thicknesses deposited on Si (100) substrate using ion beam sputtering technique. Optical response of the film was measured in 4–36?nm wavelength region using Indus-1 reflectivity beamline. A discrepancy in soft x-ray performance of NbC film was observed which could not be explained with Henke's tabulated data (see http://henke.lbl.gov/optical{sub c}onstants/ ). In order to understand this, detailed structural and chemical investigations were carried out using x-ray reflectivity, grazing incidence x-ray diffraction, x-ray absorption near edge structure, extended x-ray absorption fine structure, and x-ray photoelectron spectroscopy techniques. It was found that the presence of unreacted carbon and Nb deficiency due to reduced Nb-Nb coordination are responsible for lower soft x-ray reflectivity performance. NbC is an important material for soft x-ray optical devices, hence the structural disorder need to be controlled to achieve the best performances.

  16. Covalency Trends in Group IV Metallocene Dichlorides. Chlorine K-Edge X-Ray Absorption Spectroscopy And Time Dependent-Density Functional Theory

    SciTech Connect (OSTI)

    Kozimor, S.A.; Yang, P.; Batista, E.R.; Boland, K.S.; Burns, C.J.; Christensen, C.N.; Clark, D.L.; Conradson, S.D.; Hay, P.J.; Lezama, J.S.; Martin, R.L.; Schwarz, D.E.; Wilkerson, M.P.; Wolfsberg, L.E.

    2009-05-20

    For 3-5d transition-metal ions, the (C{sub 5}R{sub 5}){sub 2}MCl{sub 2} (R = H, Me for M = Ti, Zr, Hf) bent metallocenes represent a series of compounds that have been central in the development of organometallic chemistry and homogeneous catalysis. Here, we evaluate how changes in the principal quantum number for the group IV (C{sub 5}H{sub 5}){sub 2}MCl{sub 2} (M = Ti, Zr, Hf; 1-3, respectively) complexes affects the covalency of M-Cl bonds through application of Cl K-edge X-ray Absorption Spectroscopy (XAS). Spectra were recorded on solid samples dispersed as a thin film and encapsulated in polystyrene matrices to reliably minimize problems associated with X-ray self-absorption. The data show that XAS pre-edge intensities can be quantitatively reproduced when analytes are encapsulated in polystyrene. Cl K-edge XAS data show that covalency in M-Cl bonding changes in the order Ti > Zr > Hf and demonstrates that covalency slightly decreases with increasing principal quantum number in 1-3. The percent Cl 3p character was experimentally determined to be 26, 23, and 18% per M-Cl bond in the thin-film samples for 1-3 respectively and was indistinguishable from the polystyrene samples, which analyzed as 25, 25, and 19% for 1-3, respectively. To aid in interpretation of Cl K-edge XAS, 1-3 were also analyzed by ground-state and time-dependent density functional theory (TD-DFT) calculations. The calculated spectra and percent chlorine character are in close agreement with the experimental observations, and show 20, 18, and 17% Cl 3p character per M-Cl bond for 1-3, respectively. Polystyrene matrix encapsulation affords a convenient method to safely contain radioactive samples to extend our studies to include actinide elements, where both 5f and 6d orbitals are expected to play a role in M-Cl bonding and where transition assignments must rely on accurate theoretical calculations.

  17. X-ray Observations of Mrk 231

    E-Print Network [OSTI]

    T. J. Turner

    1998-08-10

    This paper presents new X-ray observations of Mrk 231, an active galaxy of particular interest due to its large infrared luminosity and the presence of several blueshifted broad absorption line (BAL) systems, a phenomenon observed in a small fraction of QSOs. A ROSAT HRI image of Mrk 231 is presented, this shows an extended region of soft X-ray emission, covering several tens of kpc, consistent with the extent of the host galaxy. An ASCA observation of Mrk 231 is also presented. Hard X-rays are detected but the data show no significant variability in X-ray flux. The hard X-ray continuum is heavily attenuated and X-ray column estimates range from ~ 2 x 10^{22} - 10^{23} cm^{-2} depending on whether the material is assumed to be neutral or ionized, and on the model assumed for the extended X-ray component. These ASCA data provide only the second hard X-ray spectrum of a BAL AGN presented to date. The broad-band spectral-energy-distribution of the source is discussed. While Mrk 231 is X-ray weak compared to Seyfert 1 galaxies, it has an optical-to-X-ray spectrum typical of a QSO.

  18. Controlling X-rays With Light

    SciTech Connect (OSTI)

    Glover, Ernie; Hertlein, Marcus; Southworth, Steve; Allison, Tom; van Tilborg, Jeroen; Kanter, Elliot; Krassig, B.; Varma, H.; Rude, Bruce; Santra, Robin; Belkacem, Ali; Young, Linda

    2010-08-02

    Ultrafast x-ray science is an exciting frontier that promises the visualization of electronic, atomic and molecular dynamics on atomic time and length scales. A largelyunexplored area of ultrafast x-ray science is the use of light to control how x-rays interact with matter. In order to extend control concepts established for long wavelengthprobes to the x-ray regime, the optical control field must drive a coherent electronic response on a timescale comparable to femtosecond core-hole lifetimes. An intense field is required to achieve this rapid response. Here an intense optical control pulse isobserved to efficiently modulate photoelectric absorption for x-rays and to create an ultrafast transparency window. We demonstrate an application of x-ray transparencyrelevant to ultrafast x-ray sources: an all-photonic temporal cross-correlation measurement of a femtosecond x-ray pulse. The ability to control x-ray/matterinteractions with light will create new opportunities at current and next-generation x-ray light sources.

  19. Unveiling the X-ray/UV properties of disk winds in active galactic nuclei using broad and mini-broad absorption line quasars

    E-Print Network [OSTI]

    Giustini, Margherita

    2015-01-01

    We present the results of the uniform analysis of 46 XMM-Newton observations of six BAL and seven mini-BAL QSOs belonging to the Palomar-Green Quasar catalogue. Moderate-quality X-ray spectroscopy was performed with the EPIC-pn, and allowed to characterise the general source spectral shape to be complex, significantly deviating from a power law emission. A simple power law analysis in different energy bands strongly suggests absorption to be more significant than reflection in shaping the spectra. If allowing for the absorbing gas to be either partially covering the continuum emission source or to be ionised, large column densities of the order of $10^{22-24}$ cm$^{-2}$ are inferred. When the statistics was high enough, virtually every source was found to vary in spectral shape on various time scales, from years to hours. All in all these observational results are compatible with radiation driven accretion disk winds shaping the spectra of these intriguing cosmic sources.

  20. X-ray absorption spectroscopy of LiBF 4 in propylene carbonate. A model lithium ion battery electrolyte

    SciTech Connect (OSTI)

    Smith, Jacob W.; Lam, Royce K.; Sheardy, Alex T.; Shih, Orion; Rizzuto, Anthony M.; Borodin, Oleg; Harris, Stephen J.; Prendergast, David; Saykally, Richard J.

    2014-08-20

    Since their introduction into the commercial marketplace in 1991, lithium ion batteries have become increasingly ubiquitous in portable technology. Nevertheless, improvements to existing battery technology are necessary to expand their utility for larger-scale applications, such as electric vehicles. Advances may be realized from improvements to the liquid electrolyte; however, current understanding of the liquid structure and properties remains incomplete. X-ray absorption spectroscopy of solutions of LiBF4 in propylene carbonate (PC), interpreted using first-principles electronic structure calculations within the eXcited electron and Core Hole (XCH) approximation, yields new insight into the solvation structure of the Li+ ion in this model electrolyte. By generating linear combinations of the computed spectra of Li+-associating and free PC molecules and comparing to the experimental spectrum, we find a Li+–solvent interaction number of 4.5. This result suggests that computational models of lithium ion battery electrolytes should move beyond tetrahedral coordination structures.

  1. In Situ X-Ray Probing Reveals Fingerprints of Surface Platinum Oxide

    SciTech Connect (OSTI)

    Friebel, Daniel

    2011-08-24

    In situ x-ray absorption spectroscopy (XAS) at the Pt L{sub 3} edge is a useful probe for Pt-O interactions at polymer electrolyte membrane fuel cell (PEMFC) cathodes. We show that XAS using the high energy resolution fluorescence detection (HERFD) mode, applied to a well-defined monolayer Pt/Rh(111) sample where the bulk penetrating hard x-rays probe only surface Pt atoms, provides a unique sensitivity to structure and chemical bonding at the Pt-electrolyte interface. Ab initio multiple-scattering calculations using the FEFF8 code and complementary extended x-ray absorption fine structure (EXAFS) results indicate that the commonly observed large increase of the white-line at high electrochemical potentials on PEMFC cathodes originates from platinum oxide formation, whereas previously proposed chemisorbed oxygen-containing species merely give rise to subtle spectral changes.

  2. High resolution x-ray fluorescence spectroscopy - a new technique for site- and spin-selectivity

    SciTech Connect (OSTI)

    Wang, Xin [Univ. of California, Davis, CA (United States). Dept. of Applied Science

    1996-12-01

    X-ray spectroscopy has long been used to elucidate electronic and structural information of molecules. One of the weaknesses of x-ray absorption is its sensitivity to all of the atoms of a particular element in a sample. Through out this thesis, a new technique for enhancing the site- and spin-selectivity of the x-ray absorption has been developed. By high resolution fluorescence detection, the chemical sensitivity of K emission spectra can be used to identify oxidation and spin states; it can also be used to facilitate site-selective X-ray Absorption Near Edge Structure (XANES) and site-selective Extended X-ray Absorption Fine Structure (EXAFS). The spin polarization in K fluorescence could be used to generate spin selective XANES or spin-polarized EXAFS, which provides a new measure of the spin density, or the nature of magnetic neighboring atoms. Finally, dramatic line-sharpening effects by the combination of absorption and emission processes allow observation of structure that is normally unobservable. All these unique characters can enormously simplify a complex x-ray spectrum. Applications of this novel technique have generated information from various transition-metal model compounds to metalloproteins. The absorption and emission spectra by high resolution fluorescence detection are interdependent. The ligand field multiplet model has been used for the analysis of K{alpha} and K{beta} emission spectra. First demonstration on different chemical states of Fe compounds has shown the applicability of site selectivity and spin polarization. Different interatomic distances of the same element in different chemical forms have been detected using site-selective EXAFS.

  3. On the importance of nuclear quantum motions in near edge x-ray absorption fine structure (NEXAFS) spectroscopy of molecules

    SciTech Connect (OSTI)

    Schwartz, Craig P.; Uejio, Janel S.; Saykally, Richard J.; Prendergast, David

    2009-02-26

    We report the effects of sampling nuclear quantum motion with path integral molecular dynamics (PIMD) on calculations of the nitrogen K-edge spectra of two isolated organic molecules. S-triazine, a prototypical aromatic molecule occupying primarily its vibrational ground state at room temperature, exhibits substantially improved spectral agreement when nuclear quantum effects are included via PIMD, as compared to the spectra obtained from either a single fixed-nuclei based calculation or from a series of configurations extracted from a classical molecular dynamics trajectory. Nuclear quantum dynamics can accurately explain the intrinsic broadening of certain features. Glycine, the simplest amino acid, is problematic due to large spectral variations associated with multiple energetically accessible conformations at the experimental temperature. This work highlights the sensitivity of NEXAFS to quantum nuclear motions in molecules, and the necessity of accurately sampling such quantum motion when simulating their NEXAFS spectra.

  4. Quick extended x-ray absorption fine structure instrument with millisecond time scale, optimized for in situ applications

    E-Print Network [OSTI]

    Sparks, Donald L.

    . Wang,4 A. I. Frenkel,4 N. Marinkovic,5 N. Hould,5 M. Ginder-Vogel,5 G. L. Landrot,5 D. L. Sparks,5

  5. X-ray absorption spectroscopy study of parent misfit-layered cobalt oxide [Sr?O?]q}CoO?

    SciTech Connect (OSTI)

    Chou, Ta-Lei [Laboratory of Inorganic Chemistry, Department of Chemistry, Aalto University, P.O. Box 16100, FI-00076 Aalto (Finland); Chan, Ting-Shan; Chen, Jin-Ming [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Yamauchi, Hisao [Laboratory of Inorganic Chemistry, Department of Chemistry, Aalto University, P.O. Box 16100, FI-00076 Aalto (Finland); Karppinen, Maarit, E-mail: maarit.karppinen@aalto.fi [Laboratory of Inorganic Chemistry, Department of Chemistry, Aalto University, P.O. Box 16100, FI-00076 Aalto (Finland)

    2013-06-01

    Here we present a comprehensive X-ray absorption spectroscopy study carried out at Co-L?,?, Co-K, O-K and Sr-K edges for the parent misfit-layered cobalt oxide phase [Sr?O?]?.??CoO?; comparison is made to another misfit-layered oxide [CoCa?O?]?.??CoO? and the perovskite oxide LaCoO?. A high-quality sample of [Sr?O?]?.??CoO? was obtained through ultra-high-pressure synthesis using Sr?Co?O? and Sr(OH)??8H?O as starting materials. Different dosages of KClO? were mixed with the raw materials as an oxygen source and tested, but it was found that the window for the redox control of [Sr?O?]?.??CoO? is rather narrow. From Co-K and Co-L?,? spectra a mixed III/IV valence state is revealed for cobalt in [Sr?O?]?.??}CoO?, but the average valence value is a little lower than in [CoCa?O?]?.??CoO?. Then, Sr-K spectrum indicates that the [Sr?O?] double-layer block in [Sr?O?]?.??CoO? clearly deviates from the cubic SrO rock-salt structure, suggesting a more complicated coordination environment for strontium. This together with a somewhat low Co-valence value and the fact that the phase formation of [Sr?O?]?.??CoO? required the presence of Sr(OH)??8H?O in the high-pressure synthesis suggest that the [Sr?O?] block contains ---OH groups, i.e. [Sr?(O,OH)?]?.??CoO?. - Graphical abstract: [Sr?O?]?.??CoO? obtained through high-pressure synthesis is a parent of misfit-layered cobalt oxides, such as [CoCa?O?]?.??CoO? or [MmA?O2+m]qCoO? in general. Our comprehensive X-ray absorption spectroscopy study shows that both [Sr?O?]?.??CoO? and [CoCa?O?]?.??CoO? possess mixed III/IV valence cobalt, but the average Co-valence is a little lower in the former. This is tentatively believed to be due to OH--- groups replacing part of O²? ions in the [Sr?O?] layer block. Highlights: • [Sr?O?]?.??CoO? is a parent of misfit-layered cobalt oxides. • It is obtained by ultra-high-pressure synthesis from Sr?Co?O?, Sr(OH)??6H?O and KClO?. • Co-K and Co---L XANES spectra reveal lower than expected Co-valence value. • Sr-K XANES spectrum indicates that the [Sr?O?] block is not of simple rock-salt structure. • This block most probably contains ---OH--- groups, i.e. [Sr?(O,OH)?]?.??CoO?.

  6. Simulating Ru L3-Edge X-ray Absorption Spectroscopy with Time-Dependent Density Functional Theory: Model Complexes and Electron Localization in Mixed-Valence Metal Dimers

    SciTech Connect (OSTI)

    Kuiken, Benjamin E. Van; Valiev, Marat; Daifuku, Stephanie L.; Bannan, Caitlin; Strader, Matthew L.; Cho, Hana; Huse, Nils; Schoenlein, Robert W.; Govind, Niranjan; Khalil, Munira

    2013-04-26

    Ruthenium L3-edge X-ray absorption (XA) spectroscopy probes unoccupied 4d orbitals of the metal atom and is increasingly being used to investigate the local electronic structure in ground and excited electronic states of Ru complexes. The simultaneous development of computational tools for simulating Ru L3-edge spectra is crucial for interpreting the spectral features at a molecular level. This study demonstrates that time-dependent density functional theory (TDDFT) is a viable and predictive tool for simulating ruthenium L3-edge XA spectroscopy. We systematically investigate the effects of exchange correlation functional and implicit and explicit solvent interactions on a series of RuII and RuIII complexes in their ground and electronic excited states. The TDDFT simulations reproduce all of the experimentally observed features in Ru L3-edge XA spectra within the experimental resolution (0.4 eV). Our simulations identify ligand-specific charge transfer features in complicated Ru L3-edge spectra of [Ru(CN)6]4- and RuII polypyridyl complexes illustrating the advantage of using TDDFT in complex systems. We conclude that the B3LYP functional most accurately predicts the transition energies of charge transfer features in these systems. We use our TDDFT approach to simulate experimental Ru L3-edge XA spectra of transition metal mixed-valence dimers of the form [(NC)5MII-CN-RuIII(NH3)5] (where M = Fe or Ru) dissolved in water. Our study determines the spectral signatures of electron delocalization in Ru L3-edge XA spectra. We find that the inclusion of explicit solvent molecules is necessary for reproducing the spectral features and the experimentally determined valencies in these mixed-valence complexes. This study validates the use of TDDFT for simulating Ru 2p excitations using popular quantum chemistry codes and providing a powerful interpretive tool for equilibrium and ultrafast Ru L3-edge XA spectroscopy.

  7. Tetrahalide Complexes of the [U(NR)(2)]2+ Ion: Synthesis, Theory, and Chlorine K-Edge X-ray Absorption Spectroscopy

    SciTech Connect (OSTI)

    Spencer, Liam P.; Yang, Ping; Minasian, Stefan G.; Jilek, Robert E.; Batista, Enrique R.; Boland, Kevin S.; Boncella, James M.; Conradson, S. D.; Clark, David L.; Hayton, Trevor W.; Kozimor, Stosh A.; Martin, Richard L.; MacInnes, Molly M.; Olson, Angela C.; Scott, Brian L.; Shuh, D. K.; Wilkerson, Marianne P.

    2013-02-13

    Synthetic routes to salts containing uranium bisimido tetrahalide anions [U(NR)(2)X-4](2-) (X = Cl-, Br-) and non-coordinating NEt4+ and PPh4+ countercations are reported. In general, these compounds can be prepared from U(NR)(2)I-2(THF)(x) (x = 2 and R = 'Bu, Ph; x = 3 and R = Me) upon addition of excess halide. In addition to providing stable coordination complexes with Cl-, the [U(NMe)(2)](2 +) cation also reacts with Br- to form stable [NEt4](2)[U(NMe)(2)Br-4] complexes. These materials were used as a platform to compare electronic structure and bonding in [U(NR)(2)](2+) with [UO2](2+). Specifically, Cl K-edge X-ray absorption spectroscopy (XAS) and both ground-state and time-dependent hybrid density functional theory (DFT and TDDFT) were used to probe U-Cl bonding interactions in [PPh4](2)[U((NBu)-Bu-t)(2)Cl-4] and [PPh4](2)[UO2Cl4]. The DFT and XAS results show the total amount of Cl 3p character mixed with the U 5f orbitals was roughly 7-10% per U-Cl bond for both compounds, which shows that moving from oxo to imido has little effect on orbital mixing between the U 5f and equatorial Cl 3p orbitals. The results are presented in the context of recent Cl K-edge XAS and DFT studies on other hexavalent uranium chloride systems with fewer oxo or imido ligands.

  8. Performance and characteristics of a high pressure, high temperature capillary cell with facile construction for operando x-ray absorption spectroscopy

    SciTech Connect (OSTI)

    Bansode, Atul; Urakawa, Atsushi, E-mail: aurakawa@iciq.es [Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans 16, 43007 Tarragona (Spain); Guilera, Gemma; Simonelli, Laura; Avila, Marta [ALBA Synchrotron Light Source, Crta. BP 1413, Km. 3.3, 08290 Cerdanyola del Vallès, Barcelona (Spain); Cuartero, Vera [ALBA Synchrotron Light Source, Crta. BP 1413, Km. 3.3, 08290 Cerdanyola del Vallès, Barcelona (Spain); European Synchrotron Radiation Facility (ESRF), CS40220, F-38043, Grenoble Cedex (France)

    2014-08-15

    We demonstrate the use of commercially available fused silica capillary and fittings to construct a cell for operando X-ray absorption spectroscopy (XAS) for the study of heterogeneously catalyzed reactions under high pressure (up to 200 bars) and high temperature (up to 280?°C) conditions. As the first demonstration, the cell was used for CO{sub 2} hydrogenation reaction to examine the state of copper in a conventional Cu/ZnO/Al{sub 2}O{sub 3} methanol synthesis catalyst. The active copper component of the catalyst was shown to remain in the metallic state under supercritical reaction conditions, at 200 bars and up to 260?°C. With the coiled heating system around the capillary, one can easily change the length of the capillary and control the amount of catalyst under investigation. With precise control of reactant(s) flow, the cell can mimic and serve as a conventional fixed-bed micro-reactor system to obtain reliable catalytic data. This high comparability of the reaction performance of the cell and laboratory reactors is crucial to gain insights into the nature of actual active sites under technologically relevant reaction conditions. The large length of the capillary can cause its bending upon heating when it is only fixed at both ends because of the thermal expansion. The degree of the bending can vary depending on the heating mode, and solutions to this problem are also presented. Furthermore, the cell is suitable for Raman studies, nowadays available at several beamlines for combined measurements. A concise study of CO{sub 2} phase behavior by Raman spectroscopy is presented to demonstrate a potential of the cell for combined XAS-Raman studies.

  9. Resonant Soft X-Ray Scattering - Combining Structural with Spectroscop...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    spectroscopy has become an important tool in understanding the electronic structure of materials. Resonant absorption edges in the soft x-ray regime are especially interesting...

  10. ALS X-Rays Shine a New Light on Catalysis

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    were able to directly observe redox processes in thin-film iron and cobalt perovskite oxide electrocatalysts using surface-sensitive, x-ray absorption spectroscopy while...

  11. Chest x-Rays

    Broader source: Energy.gov [DOE]

    The B-reading is a special reading of a standard chest x-ray film performed by a physician certified by the National Institute for Occupational Safety and Health (NIOSH). The reading looks for changes on the chest x-ray that may indicate exposure and disease caused by agents such as asbestos or silica.

  12. X-ray beamsplitter

    DOE Patents [OSTI]

    Ceglio, Natale M. (Livermore, CA); Stearns, Daniel S. (Mountain View, CA); Hawryluk, Andrew M. (Modesto, CA); Barbee, Jr., Troy W. (Palo Alto, CA)

    1989-01-01

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

  13. X-ray beamsplitter

    DOE Patents [OSTI]

    Ceglio, N.M.; Stearns, D.G.; Hawryluk, A.M.; Barbee, T.W. Jr.

    1987-08-07

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5--50 pairs of alternate Mo/Si layers with a period of 20--250 A. The support membrane is 10--200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window. 6 figs.

  14. X-ray laser

    DOE Patents [OSTI]

    Nilsen, Joseph (Livermore, CA)

    1991-01-01

    An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

  15. State-Dependent Electron Delocalization Dynamics at the Solute-Solvent Interface: Soft X-ray Absorption Spectroscopy and Ab Initio Calculations

    E-Print Network [OSTI]

    Bokarev, Sergey I; Suljoti, Edlira; Kühn, Oliver; Aziz, Emad F

    2013-01-01

    Non-radiative decay channels in the L-edge fluorescence spectra from transition metal-aqueous solutions give rise to spectral dips in X-ray transmission spectra. Their origin is unraveled here using partial and inverse partial fluorescence yields on the micro-jet combined with multi-reference ab initio electronic structure calculations. Comparing Fe2+, Fe3+, and Co2+ systems we demonstrate unequivocally that spectral dips are due to a state-dependent electron delocalization within the manifold of d-orbitals.

  16. X-ray microtomography

    SciTech Connect (OSTI)

    Landis, Eric N.; Keane, Denis T.

    2010-12-15

    In this tutorial, we describe X-ray microtomography as a technique to nondestructively characterize material microstructure in three dimensions at a micron level spatial resolution. While commercially available laboratory scale instrumentation is available, we focus our attention on synchrotron-based systems, where we can exploit a high flux, monochromatic X-ray beam to produce high fidelity three-dimensional images. A brief description of the physics and the mathematical analysis behind the technique is followed by example applications to specific materials characterization problems, with a particular focus on the utilization of three-dimensional image processing that can be used to extract a wide range of useful information.

  17. X-rayEmissionfromMassiveStars: UsingEmissionLineProfilestoConstrainWind

    E-Print Network [OSTI]

    Cohen, David

    X-rayEmissionfromMassiveStars: UsingEmissionLineProfilestoConstrainWind Kinematics? Pup:windX-rays,butlessabsorptionthanexpected OriandOri:similarsituation,verylittlewind absorption). Cyclicaland stochastic variabilityis seeninmost hotstars'winds #12

  18. HIGH-RESOLUTION X-RAY SPECTROSCOPY OF CRUCIS: A

    E-Print Network [OSTI]

    Cohen, David

    a corona; clear presence of UV driven wind at moderate temperatures; lack of wind X-ray absorption edges the years, consen- sus has thus instead favored an Intrinsic Wind Shock (IWS) model, in which the X-ray emission comes from shocks distributed throughout the wind, most likely arising from the strong, intrinsic

  19. X-ray magnetic circular dichroism at the U M{sub 4,5} absorption edges of UFe{sub 2}

    SciTech Connect (OSTI)

    Finazzi, M.; Sainctavit, P.; Dias, A.; Kappler, J.; Krill, G.; Sanchez, J.; Dalmas de Reotier, P.; Yaouanc, A.; Rogalev, A.; Goulon, J.

    1997-02-01

    We present an x-ray magnetic circular dichroism study performed at the U M{sub 4,5} edges on UFe{sub 2}, a ferromagnet with almost itinerant 5f electrons. The analysis of the branching ratio of the U M{sub 4,5} edges confirms the fact that the occupation number of the 5f states in UFe{sub 2} is lower than in other compounds where the f electrons are more localized. Magnetic circular dichroism effects are observed consistently with the presence of an orbital 5f magnetic moment which aligns parallel to the total magnetic moment. In agreement with a polarized neutron study, we find a nearly perfect cancellation of the U-5f spin and orbital magnetic moments, which results in a vanishing small total U-5f magnetic moment. Results are discussed in comparison with atomic multiplet calculations. {copyright} {ital 1997} {ital The American Physical Society}

  20. X-Ray Data Booklet X-RAY DATA BOOKLET

    E-Print Network [OSTI]

    X-Ray Data Booklet X-RAY DATA BOOKLET Center for X-ray Optics and Advanced Light Source Lawrence Electromagnetic Relations Radioactivity and Radiation Protection Useful Formulas CXRO Home | ALS Home | LBL Home in PDF format Data Booklet Authors CXRO Home | ALS Home | LBL Home Privacy and Security Notice Please

  1. Fluctuation X-Ray Scattering

    SciTech Connect (OSTI)

    Saldin, PI: D. K.; Co-I's: J. C. H. Spence and P. Fromme

    2013-01-25

    The work supported by the grant was aimed at developing novel methods of finding the structures of biomolecules using x-rays from novel sources such as the x-ray free electron laser and modern synchrotrons

  2. X-ray studies of concentrated aqueous solutions

    SciTech Connect (OSTI)

    Ludwig, K.F. Jr.; Warburton, W.K.; Fontaine, A.

    1987-07-01

    Concentrated aqueous solutions of three transition metal bromides (ZnBr/sub 2/, CuBr/sub 2/, and NiBr/sub 2/) and an alkali bromide (RbBr) have been studied with differential anomalous scattering (DAS) and extended x-ray absorption fine structure (EXAFS). The aq-ZnBr/sub 2/ solutions exhibit considerable inner-shell ion complexing with the formation of tetrahedral complexes about the Zn/sup 2 +/. In aq-CuBr/sub 2/, the Cu/sup 2 +/ has an octahedral coordination shell. Most of the anions are bound directly to the cations in both solutions. In contrast, there are only a few Ni--Br nearest neighbors in aq-NiBr/sub 2/. Instead, cations and anions share hydrating water molecules. Preliminary data show that any ion complexing in aq-RbBr must be weak. These results are in good agreement with published thermodynamic studies.

  3. Tunable X-ray source

    DOE Patents [OSTI]

    Boyce, James R. (Williamsburg, VA)

    2011-02-08

    A method for the production of X-ray bunches tunable in both time and energy level by generating multiple photon, X-ray, beams through the use of Thomson scattering. The method of the present invention simultaneously produces two X-ray pulses that are tunable in energy and/or time.

  4. Ge L{sub 3}-edge x-ray absorption near-edge structure study of structural changes accompanying conductivity drift in the amorphous phase of Ge{sub 2}Sb{sub 2}Te{sub 5}

    SciTech Connect (OSTI)

    Mitrofanov, K. V. [Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8562 (Japan); Kolobov, A. V., E-mail: a.kolobov@aist.go.jp; Fons, P. [Nanoelectronics Research Institute and Green Nanoelectronics Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8562, Japan and Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1, Kouto, Sayo, Hyogo 679-5198 (Japan); Wang, X.; Tominaga, J. [Nanoelectronics Research Institute and Green Nanoelectronics Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8562 (Japan); Tamenori, Y.; Uruga, T. [Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1, Kouto, Sayo, Hyogo 679-5198 (Japan); Ciocchini, N.; Ielmini, D. [DEIB - Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano (Italy)

    2014-05-07

    A gradual uncontrollable increase in the resistivity of the amorphous phase of phase-change alloys, such as Ge{sub 2}Sb{sub 2}Te{sub 5}, known as drift, is a serious technological issue for application of phase-change memory. While it has been proposed that drift is related to structural relaxation, no direct structural results have been reported so far. Here, we report the results of Ge L{sub 3}-edge x-ray absorption measurements that suggest that the drift in electrical conductivity is associated with the gradual conversion of tetrahedrally coordinated Ge sites into pyramidal sites, while the system still remains in the amorphous phase. Based on electronic configuration arguments, we propose that during this process, which is governed by the existence of lone-pair electrons, the concentration of free carriers in the system decreases resulting in an increase in resistance despite the structural relaxation towards the crystalline phase.

  5. Measurement of the x-ray mass attenuation coefficient and determination of the imaginary component of the atomic form factor of tin over the energy range of 29-60 keV

    SciTech Connect (OSTI)

    Jonge, Martin D. de; Tran, Chanh Q.; Chantler, Christopher T.; Barnea, Zwi; Dhal, Bipin B.; Paterson, David; Kanter, Elliot P.; Southworth, Stephen H.; Young, Linda; Beno, Mark A.; Linton, Jennifer A.; Jennings, Guy [X-Ray Operations and Research, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); School of Physics, University of Melbourne, Victoria 3010 (Australia); Australian Synchrotron Project, Major Projects Victoria, 800 Blackburn Road, Clayton, Victoria 3168 (Australia); Chemistry Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); BESSRC-CAT, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

    2007-03-15

    We use the x-ray extended-range technique (XERT) [C. T. Chantler et al., Phys. Rev. A 64, 062506 (2001)] to measure the mass attenuation coefficients of tin in the x-ray energy range of 29-60 keV to 0.04-3 % accuracy, and typically in the range 0.1-0.2 %. Measurements made over an extended range of the measurement parameter space are critically examined to identify, quantify, and correct a number of potential experimental systematic errors. These results represent the most extensive experimental data set for tin and include absolute mass attenuation coefficients in the regions of x-ray absorption fine structure, extended x-ray absorption fine structure, and x-ray absorption near-edge structure. The imaginary component of the atomic form factor f{sub 2} is derived from the photoelectric absorption after subtracting calculated Rayleigh and Compton scattering cross sections from the total attenuation. Comparison of the result with tabulations of calculated photoelectric absorption coefficients indicates that differences of 1-2 % persist between calculated and observed values.

  6. X-ray lithography source

    DOE Patents [OSTI]

    Piestrup, Melvin A. (Woodside, CA); Boyers, David G. (Mountain View, CA); Pincus, Cary (Sunnyvale, CA)

    1991-01-01

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and elminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an exellent moderate-priced X-ray source for lithography.

  7. X-ray compass for determining device orientation

    DOE Patents [OSTI]

    Da Silva, L.B.; Matthews, D.L.; Fitch, J.P.; Everett, M.J.; Colston, B.W.; Stone, G.F.

    1999-06-15

    An apparatus and method for determining the orientation of a device with respect to an x-ray source are disclosed. In one embodiment, the present invention is coupled to a medical device in order to determine the rotational orientation of the medical device with respect to the x-ray source. In such an embodiment, the present invention is comprised of a scintillator portion which is adapted to emit photons upon the absorption of x-rays emitted from the x-ray source. An x-ray blocking portion is coupled to the scintillator portion. The x-ray blocking portion is disposed so as to vary the quantity of x-rays which penetrate the scintillator portion based upon the particular rotational orientation of the medical device with respect to the x-ray source. A photon transport mechanism is also coupled to the scintillator portion. The photon transport mechanism is adapted to pass the photons emitted from the scintillator portion to an electronics portion. By analyzing the quantity of the photons, the electronics portion determines the rotational orientation of the medical device with respect to the x-ray source. 25 figs.

  8. X-ray compass for determining device orientation

    DOE Patents [OSTI]

    Da Silva, Luiz B. (Danville, CA); Matthews, Dennis L. (Moss Beach, CA); Fitch, Joseph P. (Livermore, CA); Everett, Matthew J. (Pleasanton, CA); Colston, Billy W. (Livermore, CA); Stone, Gary F. (Livermore, CA)

    1999-01-01

    An apparatus and method for determining the orientation of a device with respect to an x-ray source. In one embodiment, the present invention is coupled to a medical device in order to determine the rotational orientation of the medical device with respect to the x-ray source. In such an embodiment, the present invention is comprised of a scintillator portion which is adapted to emit photons upon the absorption of x-rays emitted from the x-ray source. An x-ray blocking portion is coupled to the scintillator portion. The x-ray blocking portion is disposed so as to vary the quantity of x-rays which penetrate the scintillator portion based upon the particular rotational orientation of the medical device with respect to the x-ray source. A photon transport mechanism is also coupled to the scintillator portion. The photon transport mechanism is adapted to pass the photons emitted from the scintillator portion to an electronics portion. By analyzing the quantity of the photons, the electronics portion determines the rotational orientation of the medical device with respect to the x-ray source.

  9. X-ray Spectroscopy of Massive Star Winds: Shocks, Mass-Loss Rates, and Clumping

    E-Print Network [OSTI]

    Cohen, David

    X-ray Spectroscopy of Massive Star Winds: Shocks, Mass-Loss Rates, and Clumping David Cohen X-rays A. wind-shock physics B. wind absorption: wind mass-loss rate C. with H-alpha: wind clumping Chandra resolved X-ray line profile spectroscopy of O star winds #12;Prior to 2000: only low-resolution X

  10. X-ray Spectroscopy of O Supergiant Winds: Shock Physics, Clumping, and Mass-Loss Rates

    E-Print Network [OSTI]

    Cohen, David

    X-ray Spectroscopy of O Supergiant Winds: Shock Physics, Clumping, and Mass-Loss Rates David Cohen-ray emission: wind shocks 1. X-ray constraints on the shocked wind plasma 2. X-ray absorption as a mass. Adiabatic shocks Open questions: very dense winds (WR stars); low density winds (B stars); magnetic OB stars

  11. Spectral Modeling of X-rays from Hot Star Winds Emma E. Wollman, Swarthmore College `09

    E-Print Network [OSTI]

    Cohen, David

    and absorption. Consequently, the more luminous a star is, the stronger the wind it can support. This wind-driving1 Spectral Modeling of X-rays from Hot Star Winds Emma E. Wollman, Swarthmore College `09 Prof x-ray spectra from Chandra's archive. Models of x-ray production in hot star winds predict broad

  12. X-Ray Diagnostics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAbout /Two0PhotosPresentationsWorld's largest singleX-Ray

  13. High resolution, multiple-energy linear sweep detector for x-ray imaging

    DOE Patents [OSTI]

    Perez-Mendez, V.; Goodman, C.A.

    1996-08-20

    Apparatus is disclosed for generating plural electrical signals in a single scan in response to incident X-rays received from an object. Each electrical signal represents an image of the object at a different range of energies of the incident X-rays. The apparatus comprises a first X-ray detector, a second X-ray detector stacked upstream of the first X-ray detector, and an X-ray absorber stacked upstream of the first X-ray detector. The X-ray absorber provides an energy-dependent absorption of the incident X-rays before they are incident at the first X-ray detector, but provides no absorption of the incident X-rays before they are incident at the second X-ray detector. The first X-ray detector includes a linear array of first pixels, each of which produces an electrical output in response to the incident X-rays in a first range of energies. The first X-ray detector also includes a circuit that generates a first electrical signal in response to the electrical output of each of the first pixels. The second X-ray detector includes a linear array of second pixels, each of which produces an electrical output in response to the incident X-rays in a second range of energies, broader than the first range of energies. The second X-ray detector also includes a circuit that generates a second electrical signal in response to the electrical output of each of the second pixels. 12 figs.

  14. High resolution, multiple-energy linear sweep detector for x-ray imaging

    DOE Patents [OSTI]

    Perez-Mendez, Victor (Berkeley, CA); Goodman, Claude A. (Kensington, CA)

    1996-01-01

    Apparatus for generating plural electrical signals in a single scan in response to incident X-rays received from an object. Each electrical signal represents an image of the object at a different range of energies of the incident X-rays. The apparatus comprises a first X-ray detector, a second X-ray detector stacked upstream of the first X-ray detector, and an X-ray absorber stacked upstream of the first X-ray detector. The X-ray absorber provides an energy-dependent absorption of the incident X-rays before they are incident at the first X-ray detector, but provides no absorption of the incident X-rays before they are incident at the second X-ray detector. The first X-ray detector includes a linear array of first pixels, each of which produces an electrical output in response to the incident X-rays in a first range of energies. The first X-ray detector also includes a circuit that generates a first electrical signal in response to the electrical output of each of the first pixels. The second X-ray detector includes a linear array of second pixels, each of which produces an electrical output in response to the incident X-rays in a second range of energies, broader than the first range of energies. The second X-ray detector also includes a circuit that generates a second electrical signal in response to the electrical output of each of the second pixels.

  15. X-ray spectrometry

    SciTech Connect (OSTI)

    Markowicz, A.A.; Van Grieken, R.E.

    1986-04-01

    In the period under review, i.e, through 1984 and 1985, some 600 articles on XRS (X-ray spectrometry) were published; most of these have been scanned and the most fundamental ones are discussed. All references will refer to English-language articles, unless states otherwise. Also general books have appeared on quantitative EPXMA (electron-probe X-ray microanalysis) and analytical electron microscopy (AEM) as well as an extensive review on the application of XRS to trace analysis of environmental samples. In the period under review no radically new developments have been seen in XRS. However, significant improvements have been made. Gain in intensities has been achieved by more efficient excitation, higher reflectivity of dispersing media, and better geometry. Better understanding of the physical process of photon- and electron-specimen interactions led to complex but more accurate equations for correction of various interelement effects. Extensive use of micro- and minicomputers now enables fully automatic operation, including qualitative analysis. However, sample preparation and presentation still put a limit to further progress. Although some authors find XRS in the phase of stabilization or even stagnation, further gradual developments are expected, particularly toward more dedicated equipment, advanced automation, and image analysis systems. Ways are outlined in which XRS has been improved in the 2 last years by excitation, detection, instrumental, methodological, and theoretical advances. 340 references.

  16. Miniature x-ray source

    DOE Patents [OSTI]

    Trebes, James E. (Livermore, CA); Stone, Gary F. (Livermore, CA); Bell, Perry M. (Tracy, CA); Robinson, Ronald B. (Modesto, CA); Chornenky, Victor I. (Minnetonka, MN)

    2002-01-01

    A miniature x-ray source capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature x-ray source comprises a compact vacuum tube assembly containing a cathode, an anode, a high voltage feedthru for delivering high voltage to the anode, a getter for maintaining high vacuum, a connection for an initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is highly x-ray transparent and made, for example, from boron nitride. The compact size and potential for remote operation allows the x-ray source, for example, to be placed adjacent to a material sample undergoing analysis or in proximity to the region to be treated for medical applications.

  17. X-Ray Interactions with Matter from the Center for X-Ray Optics (CXRO)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Henke, B. L.; Gullikson, E. M.; Davis, J. C.

    The primary interactions of low-energy x-rays within condensed matter, viz. photoabsorption and coherent scattering, are described for photon energies outside the absorption threshold regions by using atomic scattering factors. The atomic scattering factors may be accurately determined from the atomic photoabsorption cross sections using modified Kramers-Kronig dispersion relations. From a synthesis of the currently available experimental data and recent theoretical calculations for photoabsorption, the angle-independent, forward-scattering components of the atomic scattering factors have been thus semiempirically determined and tabulated here for 92 elements and for the region 50-30,000 eV. Atomic scattering factors for all angles of coherent scattering and at the higher photon energies are obtained from these tabulated forward-scattering values by adding a simple angle-dependent form-factor correction. The incoherent scattering contributions that become significant for the light elements at the higher photon energies are similarly determined. The basic x-ray interaction relations that are used in applied x-ray physics are presented here in terms of the atomic scattering factors. The bulk optical constants are also related to the atomic scattering factors. These atomic and optical relations are applied to the detailed calculation of the reflectivity characteristics of a series of practical x-ray mirror, multilayer, and crystal monochromators. Comparisons of the results of this semiempirical,"atom-like", description of x-ray interactions for the low-energy region with those of experiment and ab initio theory are presented.

  18. Resonant x-ray magnetic scattering in holmium

    SciTech Connect (OSTI)

    Gibbs, D.

    1991-01-01

    We review the results of resonant x-ray magnetic scattering experiments on the rare earth metal holmium. When the incident incident x-ray energy is tuned near the L{sub III} absorption edge, large resonant enhancements of the magnetic scattering and resonant integer harmonics are observed. These results are analyzed within the theory of x-ray resonance exchange scattering assuming electric dipole (2p {yields} 5d) and quadrupole (2p {yields} 4f) transitions among atomic orbitals. 30 refs., 5 figs.

  19. X-ray shearing interferometer

    DOE Patents [OSTI]

    Koch, Jeffrey A. (Livermore, CA)

    2003-07-08

    An x-ray interferometer for analyzing high density plasmas and optically opaque materials includes a point-like x-ray source for providing a broadband x-ray source. The x-rays are directed through a target material and then are reflected by a high-quality ellipsoidally-bent imaging crystal to a diffraction grating disposed at 1.times. magnification. A spherically-bent imaging crystal is employed when the x-rays that are incident on the crystal surface are normal to that surface. The diffraction grating produces multiple beams which interfere with one another to produce an interference pattern which contains information about the target. A detector is disposed at the position of the image of the target produced by the interfering beams.

  20. X-ray fluorescence mapping

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWindX-RayX-Ray ScienceX-Ray

  1. Soft-x-ray spectroscopy study of nanoscale materials

    SciTech Connect (OSTI)

    Guo, J.-H.

    2005-07-30

    The ability to control the particle size and morphology of nanoparticles is of crucial importance nowadays both from a fundamental and industrial point of view considering the tremendous amount of high-tech applications. Controlling the crystallographic structure and the arrangement of atoms along the surface of nanostructured material will determine most of its physical properties. In general, electronic structure ultimately determines the properties of matter. Soft X-ray spectroscopy has some basic features that are important to consider. X-ray is originating from an electronic transition between a localized core state and a valence state. As a core state is involved, elemental selectivity is obtained because the core levels of different elements are well separated in energy, meaning that the involvement of the inner level makes this probe localized to one specific atomic site around which the electronic structure is reflected as a partial density-of-states contribution. The participation of valence electrons gives the method chemical state sensitivity and further, the dipole nature of the transitions gives particular symmetry information. The new generation synchrotron radiation sources producing intensive tunable monochromatized soft X-ray beams have opened up new possibilities for soft X-ray spectroscopy. The introduction of selectively excited soft X-ray emission has opened a new field of study by disclosing many new possibilities of soft X-ray resonant inelastic scattering. In this paper, some recent findings regarding soft X-ray absorption and emission studies of various nanostructured systems are presented.

  2. Center for X-Ray Optics, 1992

    SciTech Connect (OSTI)

    Not Available

    1993-08-01

    This report discusses the following topics: Center for X-Ray Optics; Soft X-Ray Imaging wit Zone Plate Lenses; Biological X-Ray microscopy; Extreme Ultraviolet Lithography for Nanoelectronic Pattern Transfer; Multilayer Reflective Optics; EUV/Soft X-ray Reflectometer; Photoemission Microscopy with Reflective Optics; Spectroscopy with Soft X-Rays; Hard X-Ray Microprobe; Coronary Angiography; and Atomic Scattering Factors.

  3. Miniature x-ray source

    DOE Patents [OSTI]

    Trebes, James E. (Livermore, CA); Bell, Perry M. (Tracy, CA); Robinson, Ronald B. (Modesto, CA)

    2000-01-01

    A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

  4. Dopant site selectivity in BaCe0.85M0.15O3-by extended x-ray absorption fine structure

    E-Print Network [OSTI]

    Haile, Sossina M.

    solid oxide fuel cells and in hydrogen sensors.1­3 Proton incorporation requires, as a first step compensating defects for dopant ions and which are later exchanged with protons under hydrogen atmospheres lead barium oxide evaporation at high temperatures, en- suring that the overall A:B mole ratio in the ABO3

  5. Anisotropic orbital occupation and Jahn-Teller distortion of orthorhombic YMnO{sub 3} epitaxial films: A combined experimental and theoretical study on polarization-dependent x-ray absorption spectroscopy

    SciTech Connect (OSTI)

    Haw, Shu-Chih; Chen, Shin-Ann [Department of Engineering and System Science, National Tsing Hua University, 30013 Hsinchu, Taiwan (China) [Department of Engineering and System Science, National Tsing Hua University, 30013 Hsinchu, Taiwan (China); National Synchrotron Radiation Research Center (NSRRC), 101 HsinAnn Road, 30076 Hsinchu, Taiwan (China); Lee, Jenn-Min; Lu, Kueih-Tzu; Lee, Ming-Tao; Pi, Tun-Wen; Chen, Jin-Ming, E-mail: jmchen@nsrrc.org.tw, E-mail: Zhiwei.Hu@cpfs.mpg.de [National Synchrotron Radiation Research Center (NSRRC), 101 HsinAnn Road, 30076 Hsinchu, Taiwan (China)] [National Synchrotron Radiation Research Center (NSRRC), 101 HsinAnn Road, 30076 Hsinchu, Taiwan (China); Lin, Pao-An [Department of Physics, National Tsing Hua University, 30013 Hsinchu, Taiwan (China)] [Department of Physics, National Tsing Hua University, 30013 Hsinchu, Taiwan (China); Lee, Chih-Hao [Department of Engineering and System Science, National Tsing Hua University, 30013 Hsinchu, Taiwan (China)] [Department of Engineering and System Science, National Tsing Hua University, 30013 Hsinchu, Taiwan (China); Hu, Zhiwei, E-mail: jmchen@nsrrc.org.tw, E-mail: Zhiwei.Hu@cpfs.mpg.de [Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden (Germany)] [Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden (Germany)

    2014-04-21

    The b-axis oriented orthorhombic YMnO{sub 3} (o-YMnO{sub 3}) epitaxial films on a YAlO{sub 3} (010) substrate were fabricated with pulsed-laser deposition. The anisotropic orbital occupation and Jahn-Teller (JT) distortion of an o-YMnO{sub 3} film were investigated with polarization-dependent x-ray absorption spectra and configuration-interaction multiplet-cluster calculations. A significant energy difference, ?3.8 eV, for the main white line along E//b and E//a in polarization-dependent Mn K-edge spectra of o-YMnO{sub 3} indicates an extraordinary JT distortion and significant anisotropic Mn–O bonding within the ab plane in the o-YMnO{sub 3} film. Most importantly, although the orbital occupation of 3d electrons in o-YMnO{sub 3} films is almost the same as that in single crystalline o-DyMnO{sub 3}, the JT distortion of o-YMnO{sub 3} films is larger than that of single crystalline o-DyMnO{sub 3}, deduced from the multiplet calculations. We speculate that this JT distortion predominantly contributes to the origin of the cycloidal spin deformation in bulk o-YMnO{sub 3}, because of a suppressed nearest-neighbor superexchange interaction and an enhanced next-nearest-neighbor superexchange interaction. These complementary results provide insight into the origin of the E-type magnetic configuration of o-YMnO{sub 3}.

  6. Soft X-ray Spectroscopy Study of the Electronic Structure of Oxidized and Partially Oxidized Magnetite Nanoparticles

    SciTech Connect (OSTI)

    Gilbert, Benjamin; Katz, Jordan E.; Denlinger, Jonathan D.; Yin, Yadong; Falcone, Roger; Waychunas, Glenn A.

    2010-10-24

    The crystal structure of magnetite nanoparticles may be transformed to maghemite by complete oxidation, but under many relevant conditions the oxidation is partial, creating a mixed-valence material with structural and electronic properties that are poorly characterized. We used X-ray diffraction, Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy, and soft X-ray absorption and emission spectroscopy to characterize the products of oxidizing uncoated and oleic acid-coated magnetite nanoparticles in air. The oxidization of uncoated magnetite nanoparticles creates a material that is structurally and electronically indistinguishable from maghemite. By contrast, while oxidized oleic acid-coated nanoparticles are also structurally indistinguishable from maghemite, Fe L-edge spectroscopy revealed the presence of interior reduced iron sites even after a 2-year period. We used X-ray emission spectroscopy at the O K-edge to study the valence bands (VB) of the iron oxide nanoparticles, using resonant excitation to remove the contributions from oxygen atoms in the ligands and from low-energy excitations that obscured the VB edge. The bonding in all nanoparticles was typical of maghemite, with no detectable VB states introduced by the long-lived, reduced-iron sites in the oleic acid-coated sample. However, O K-edge absorption spectroscopy observed a 0.2 eV shift in the position of the lowest unoccupied states in the coated sample, indicating an increase in the semiconductor band gap relative to bulk stoichiometric maghemite that was also observed by optical absorption spectroscopy. The results show that the ferrous iron sites within ferric iron oxide nanoparticles coated by an organic ligand can persist under ambient conditions with no evidence of a distinct interior phase and can exert an effect on the global electronic and optical properties of the material. This phenomenon resembles the band gap enlargement caused by electron accumulation in the conduction band of TiO2.

  7. Synthesis and x-ray characterization of cobalt phosphide (Co?P) nanorods for the oxygen reduction reaction

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Doan-Nguyen, Vicky V.T.; Su, Dong; Zhang, Sen; Trigg, Edward B.; Agarwal, Rahul; Li, Jing; Winey, Karen I.; Murray, Christopher B.

    2015-07-14

    Low temperature fuel cells are clean, effective alternative fuel conversion technology. Oxygen reduction reaction (ORR) at the fuel cell cathode has required Pt as the electrocatalyst for high activity and selectivity of the four-electron reaction pathway. Targeting a less expensive, earth abundant alternative, we have developed the synthesis of cobalt phosphide (Co?P) nanorods for ORR. Characterization techniques that include total X-ray scattering and extended X-ray absorption fine structure revealed a deviation of the nanorods from bulk crystal structure with a contraction along the b orthorhombic lattice parameter. The carbon supported nanorods have comparable activity but are remarkably more stable thanmore »conventional Pt catalysts for the oxygen reduction reaction in alkaline environments.« less

  8. Method and apparatus for molecular imaging using X-rays at resonance wavelengths

    DOE Patents [OSTI]

    Chapline, Jr., George F. (Alamo, CA)

    1985-01-01

    Holographic X-ray images are produced representing the molecular structure of a microscopic object, such as a living cell, by directing a beam of coherent X-rays upon the object to produce scattering of the X-rays by the object, producing interference on a recording medium between the scattered X-rays from the object and unscattered coherent X-rays and thereby producing holograms on the recording surface, and establishing the wavelength of the coherent X-rays to correspond with a molecular resonance of a constituent of such object and thereby greatly improving the contrast, sensitivity and resolution of the holograms as representations of molecular structures involving such constituent. For example, the coherent X-rays may be adjusted to the molecular resonant absorption line of nitrogen at about 401.3 eV to produce holographic images featuring molecular structures involving nitrogen.

  9. Ultrafast X-ray Sources

    SciTech Connect (OSTI)

    George Neil

    2010-04-19

    Since before the scattering of X-rays off of DNA led to the first understanding of the double helix structure, sources of X-rays have been an essential tool for scientists examining the structure and interactions of matter. The resolution of a microscope is proportional to the wavelength of light so x-rays can see much finer structures than visible light, down to single atoms. In addition, the energy of X-rays is resonant with the core atomic levels of atoms so with appropriate wavelengths the placement of specific atoms in a large molecule can be determined. Over 10,000 scientists use synchrotron sources, storage rings of high energy electrons, each year worldwide. As an example of such use, virtually every picture of a protein or drug molecule that one sees in the scientific press is a reconstruction based on X-ray scattering of synchrotron light from the crystallized form of that molecule. Unfortunately those pictures are static and proteins work through configuration (shape) changes in response to energy transfer. To understand how biological systems work requires following the energy flow to these molecules and tracking how shape changes drive their interaction with other molecules. We'd like to be able to freeze the action of these molecules at various steps along the way with an X-ray strobe light. How fast does it have to be? To actually get a picture of a molecule in a fixed configuration requires X-ray pulses as short as 30 femtoseconds (1/30 of a millionth of a millionth of a second). To capture the energy flow through changes in electronic levels requires a faster strobe, less than 1 femtosecond! And to acquire such information in smaller samples with higher accuracy demands brighter and brighter X-rays. Unfortunately modern synchrotrons (dubbed 3rd Generation Light Sources) cannot deliver such short bright pulses of X-rays. An entirely new approach is required, linear-accelerator (linac-)-based light sources termed 4th or Next Generation Light Sources (NGLSs). Although NGLSs will not displace synchrotrons from their role they do offer exciting new capabilities which can be understood from the physics of the light production in each device.

  10. A short working distance multiple crystal x-ray spectrometer

    SciTech Connect (OSTI)

    Dickinson, B.; Seidler, G. T.; Webb, Z. W.; Bradley, J. A.; Nagle, K. P. [Department of Physics, University of Washington, Seattle, Washington 98195 (United States); Heald, S. M. [Advanced Photon Source, Argonne National Laboratories, Argonne, Illinois 60439 (United States); Gordon, R. A. [Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Chou, I. M. [U.S. Geological Survey, Reston, Virginia 20192 (United States)

    2008-12-15

    For x-ray spot sizes of a few tens of microns or smaller, a millimeter-sized flat analyzer crystal placed {approx}1 cm from the sample will exhibit high energy resolution while subtending a collection solid angle comparable to that of a typical spherically bent crystal analyzer (SBCA) at much larger working distances. Based on this observation and a nonfocusing geometry for the analyzer optic, we have constructed and tested a short working distance (SWD) multicrystal x-ray spectrometer. This prototype instrument has a maximum effective collection solid angle of 0.14 sr, comparable to that of 17 SBCA at 1 m working distance. We find good agreement with prior work for measurements of the Mn K{beta} x-ray emission and resonant inelastic x-ray scattering for MnO, and also for measurements of the x-ray absorption near-edge structure for Dy metal using L{alpha}{sub 2} partial-fluorescence yield detection. We discuss future applications at third- and fourth-generation light sources. For concentrated samples, the extremely large collection angle of SWD spectrometers will permit collection of high-resolution x-ray emission spectra with a single pulse of the Linac Coherent Light Source. The range of applications of SWD spectrometers and traditional multi-SBCA instruments has some overlap, but also is significantly complementary.

  11. Compact x-ray source and panel

    DOE Patents [OSTI]

    Sampayon, Stephen E. (Manteca, CA)

    2008-02-12

    A compact, self-contained x-ray source, and a compact x-ray source panel having a plurality of such x-ray sources arranged in a preferably broad-area pixelized array. Each x-ray source includes an electron source for producing an electron beam, an x-ray conversion target, and a multilayer insulator separating the electron source and the x-ray conversion target from each other. The multi-layer insulator preferably has a cylindrical configuration with a plurality of alternating insulator and conductor layers surrounding an acceleration channel leading from the electron source to the x-ray conversion target. A power source is connected to each x-ray source of the array to produce an accelerating gradient between the electron source and x-ray conversion target in any one or more of the x-ray sources independent of other x-ray sources in the array, so as to accelerate an electron beam towards the x-ray conversion target. The multilayer insulator enables relatively short separation distances between the electron source and the x-ray conversion target so that a thin panel is possible for compactness. This is due to the ability of the plurality of alternating insulator and conductor layers of the multilayer insulators to resist surface flashover when sufficiently high acceleration energies necessary for x-ray generation are supplied by the power source to the x-ray sources.

  12. Determining Relative f and d Orbital Contributions to M?Cl Covalency in MCl62– (M = Ti, Zr, Hf, U) and UOCl5 Using Cl K-Edge X-ray Absorption Spectroscopy and Time-Dependent Density Functional Theory

    SciTech Connect (OSTI)

    Minasian, Stefan G.; Keith, Jason M.; Batista, Enrique R.; Boland, Kevin S.; Clark, David L.; Conradson, Steven D.; Kozimor, Stosh A.; Martin, Richard L.; Schwarz, Daniel E.; Shuh, David K.; Wagner, Gregory L.; Wilkerson, Marianne P.; Wolfsberg, Laura E.; Yang, Ping

    2012-03-09

    Chlorine K-edge X-ray absorption spectroscopy (XAS) and ground-state and time-dependent hybrid density functional theory (DFT) were used to probe electronic structure for O{sub h}-MCl{sub 6}{sup 2-}(M = Ti, Zr, Hf, U) and C{sub 4v}-UOCl{sub 5}{sup -}, and to determine the relative contributions of valence 3d, 4d, 5d, 6d, and 5f orbitals in M-Cl bonding. Spectral interpretations were guided by time-dependent DFT calculated transition energies and oscillator strengths, which agree well with the experimental XAS spectra. The data provide new spectroscopic evidence for the involvement of both 5f and 6d orbitals in actinide-ligand bonding in UCl{sub 6}{sup 2-}. For the MCl{sub 6}{sup 2-}, where transitions into d orbitals of t{sub 2g} symmetry are spectroscopically resolved for all four complexes, the experimentally determined Cl 3p character per M-Cl bond increases from 8.3(4)% (TiCl{sub 6}{sup 2-}) to 10.3(5)% (ZrCl{sub 6}{sup 2-}), 12(1)% (HfCl{sub 6}{sup 2-}), and 26 18(1)% (UCl{sub 6}{sup 2-}). Chlorine K-edge XAS spectra of UOCl{sub 5}{sup -} provide additional insights into the transition assignments by 27 lowering the symmetry to C{sub 4v}, where five pre-edge transitions into both 5f and 6d orbitals are observed. For UCl{sub 6}{sup 2-}, the XAS data 28 suggest that orbital mixing associated with the U 5f orbitals is considerably lower than that of the U 6d orbitals. For both UCl{sub 6}{sup 2-}29 and UOCl{sub 5}{sup -}, the ground-state DFT calculations predict a larger 5f contribution to bonding than is determined experimentally. 30 These findings are discussed in the context of conventional theories of covalent bonding for d- and f-block metal complexes.

  13. Focused X-ray source

    DOE Patents [OSTI]

    Piestrup, Melvin A. (Woodside, CA); Boyers, David G. (Mountain View, CA); Pincus, Cary I. (Sunnyvale, CA); Maccagno, Pierre (Stanford, CA)

    1990-01-01

    An intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator.

  14. Soft X-ray microflares

    E-Print Network [OSTI]

    Mirzoeva, I K

    2015-01-01

    Soft X-ray solar bursts are studied. Weak bursts with powers up to 10-8 W/m2 were detected. All the events were confirmed by GOES observations. Parameters of these microflares are determined. A physical mechanism for the low-intensity solar events is discussed.

  15. Focused X-ray source

    DOE Patents [OSTI]

    Piestrup, M.A.; Boyers, D.G.; Pincus, C.I.; Maccagno, P.

    1990-08-21

    Disclosed is an intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator. 8 figs.

  16. Ultrafast conversions between hydrogen bonded structures in liquid water observed by femtosecond x-ray spectroscopy

    E-Print Network [OSTI]

    Ultrafast conversions between hydrogen bonded structures in liquid water observed by femtosecond x the first femtosecond soft x-ray spectroscopy in liquids, enabling the observation of changes in hydrogen, characteristic x-ray absorption changes monitor the conversion of strongly hydrogen-bonded water structures

  17. Reverse engineering the ancient ceramic technology based on X-ray fluorescence spectromicroscopy

    E-Print Network [OSTI]

    Reverse engineering the ancient ceramic technology based on X-ray fluorescence spectromicroscopy-ray fluorescence (XRF) microprobe analyses of ancient ceramic cross-sections aiming at deciphering the different and Fe K-edge X-ray absorption near edge structure spectroscopy were performed on pre-sigillata ceramics

  18. ON RELATIVISTIC DISK SPECTROSCOPY IN COMPACT OBJECTS WITH X-RAY CCD CAMERAS

    E-Print Network [OSTI]

    Miller, J. M.

    X-ray charge-coupled devices (CCDs) are the workhorse detectors of modern X-ray astronomy. Typically covering the 0.3-10.0 keV energy range, CCDs are able to detect photoelectric absorption edges and K shell lines from ...

  19. Multilayer graphene stacks grown by different methods-thickness measurements by X-ray diffraction, Raman spectroscopy and optical transmission

    SciTech Connect (OSTI)

    Tokarczyk, M., E-mail: mateusz.tokarczyk@fuw.edu.pl; Kowalski, G.; K?pa, H.; Grodecki, K.; Drabi?ska, A. [University of Warsaw, Institute of Experimental Physics, Faculty of Physics (Poland); Strupi?ski, W. [Institute of Electronic Materials Technology (Poland)

    2013-12-15

    X-ray diffraction, Raman spectroscopy and Optical absorption estimates of the thickness of graphene multi layer stacks (number of graphene layers) are presented for three different growth techniques. The objective of this work was focused on comparison and reconciliation of the two already widely used methods for thickness estimates (Raman and Absorption) with the calibration of the X-ray method as far as Scherer constant K is concerned and X-ray based Wagner-Aqua extrapolation method.

  20. X-RAY EMISSION FROM MAGNETIC MASSIVE STARS

    SciTech Connect (OSTI)

    Nazé, Yaël; Petit, Véronique; Rinbrand, Melanie; Owocki, Stan; Cohen, David; Ud-Doula, Asif; Wade, Gregg A.

    2014-11-01

    Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ?60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower- M-dot B stars and flattens for the more luminous, higher- M-dot O stars. As the winds are radiatively driven, these scalings can be equivalently written as relations with the bolometric luminosity. The observed X-ray luminosities, and their trend with mass-loss rates, are well reproduced by new MHD models, although a few overluminous stars (mostly rapidly rotating objects) exist. No relation is found between other X-ray properties (plasma temperature, absorption) and stellar or magnetic parameters, contrary to expectations (e.g., higher temperature for stronger mass-loss rate). This suggests that the main driver for the plasma properties is different from the main determinant of the X-ray luminosity. Finally, variations of the X-ray hardnesses and luminosities, in phase with the stellar rotation period, are detected for some objects and they suggest that some temperature stratification exists in massive stars' magnetospheres.

  1. Eta Car and Its Surroundings: the X-ray Diagnosis

    E-Print Network [OSTI]

    M. F. Corcoran; K. Hamaguchi

    2007-03-02

    X-ray emission from the supermassive star Eta Carinae (\\ec) originates from hot shocked gas produced by current stellar mass loss as well as ejecta from prior eruptive events. Absorption of this emission by cool material allows the determination of the spatial and temporal distribution of this material. Emission from the shocked gas can provide important information about abundances through the study of thermal X-ray line emission. We discuss how studies of the X-ray emission from Eta Car at a variety of temporal, spatial and spectral scales and resolutions have helped refine our knowledge of both the continuous and discrete mass loss from the system, and its interactions with more extended material around the star.

  2. Producing X-rays at the APS

    ScienceCinema (OSTI)

    None

    2013-04-19

    An introduction and overview of the Advanced Photon Source at Argonne National Laboratory, the technology that produces the brightest X-ray beams in the Western Hemisphere, and the research carried out by scientists using those X-rays.

  3. Microgap x-ray detector

    DOE Patents [OSTI]

    Wuest, Craig R. (Danville, CA); Bionta, Richard M. (Livermore, CA); Ables, Elden (Livermore, CA)

    1994-01-01

    An x-ray detector which provides for the conversion of x-ray photons into photoelectrons and subsequent amplification of these photoelectrons through the generation of electron avalanches in a thin gas-filled region subject to a high electric potential. The detector comprises a cathode (photocathode) and an anode separated by the thin, gas-filled region. The cathode may comprise a substrate, such a beryllium, coated with a layer of high atomic number material, such as gold, while the anode can be a single conducting plane of material, such as gold, or a plane of resistive material, such as chromium/silicon monoxide, or multiple areas of conductive or resistive material, mounted on a substrate composed of glass, plastic or ceramic. The charge collected from each electron avalanche by the anode is passed through processing electronics to a point of use, such as an oscilloscope.

  4. Microgap x-ray detector

    DOE Patents [OSTI]

    Wuest, C.R.; Bionta, R.M.; Ables, E.

    1994-05-03

    An x-ray detector is disclosed which provides for the conversion of x-ray photons into photoelectrons and subsequent amplification of these photoelectrons through the generation of electron avalanches in a thin gas-filled region subject to a high electric potential. The detector comprises a cathode (photocathode) and an anode separated by the thin, gas-filled region. The cathode may comprise a substrate, such a beryllium, coated with a layer of high atomic number material, such as gold, while the anode can be a single conducting plane of material, such as gold, or a plane of resistive material, such as chromium/silicon monoxide, or multiple areas of conductive or resistive material, mounted on a substrate composed of glass, plastic or ceramic. The charge collected from each electron avalanche by the anode is passed through processing electronics to a point of use, such as an oscilloscope. 3 figures.

  5. X-ray Properties of Young Stellar Objects in OMC-2 and OMC-3 from the Chandra X-ray Observatory

    E-Print Network [OSTI]

    M. Tsujimoto; K. Koyama; Y. Tsuboi; M. Goto; N. Kobayashi

    2001-10-12

    We report X-ray results of the Chandra observation of Orion Molecular Cloud 2 and 3. A deep exposure of \\sim 100 ksec detects \\sim 400 X-ray sources in the field of view of the ACIS array, providing one of the largest X-ray catalogs in a star forming region. Coherent studies of the source detection, time variability, and energy spectra are performed. We classify the X-ray sources into class I, class II, and class III+MS based on the J, H, and K-band colors of their near infrared counterparts and discuss the X-ray properties (temperature, absorption, and time variability) along these evolutionary phases.

  6. Phase-sensitive X-ray imager

    DOE Patents [OSTI]

    Baker, Kevin Louis

    2013-01-08

    X-ray phase sensitive wave-front sensor techniques are detailed that are capable of measuring the entire two-dimensional x-ray electric field, both the amplitude and phase, with a single measurement. These Hartmann sensing and 2-D Shear interferometry wave-front sensors do not require a temporally coherent source and are therefore compatible with x-ray tubes and also with laser-produced or x-pinch x-ray sources.

  7. Trends in Covalency for d- and f-Element Metallocene Dichlorides Identified Using Chlorine K-Edge X-Ray Absorption Spectroscopy and Time Dependent-Density Functional Theory

    SciTech Connect (OSTI)

    Kozimor, Stosh A.; Yang, Ping; Batista, Enrique R.; Boland, Kevin S.; Burns, Carol J.; Clark, David L.; Conradson, Steven D.; Martin, Richard L.; Wikerson, Marianne P.; Wolfsberg, Laura E.

    2009-09-02

    We describe the use of Cl K-edge X-ray Absorption Spectroscopy (XAS) and both ground state and time-dependent hybrid density functional theory (DFT) to probe electronic structure and determine the degree of orbital mixing in M-Cl bonds for (C5Me5)2MCl2 (M = Ti, 1; Zr, 2; Hf, 3; Th, 4; and U, 5), where we can directly compare a class of structurally similar compounds for d- and f-elements. We report direct experimental evidence for covalency in M-Cl bonding, including actinides, and offer insight into the relative roles of the valence f- and dorbitals in these systems. The Cl K-edge XAS data for the group IV transition metals, 1 – 3, show slight decreases in covalency in M-Cl bonding with increasing principal quantum number, in the order Ti > Zr > Hf. The percent Cl 3p character per M-Cl bond was experimentally determined to be 25, 23, and 22% per M-Cl bond for 1-3, respectively. For actinides, we find a shoulder on the white line for (C5Me5)2ThCl2, 4, and distinct, but weak pre-edge features for 2 (C5Me5)2UCl2, 5. The percent Cl 3p character in Th-Cl bonds in 4 was determined to be 14 %, with high uncertainty, while the U-Cl bonds in 5 contains 9 % Cl 3p character. The magnitudes of both values are approximately half what was observed for the transition metal complexes in this class of bent metallocene dichlorides. Using the hybrid DFT calculations as a guide to interpret the experimental Cl K-edge XAS, these experiments suggest that when evaluating An- Cl bonding, both 5f- and 6d-orbitals should be considered. For (C5Me5)2ThCl2, the calculations and XAS indicate that the 5f- and 6d-orbitals are nearly degenerate and heavily mixed. In contrast, the 5f- and 6d-orbitals in (C5Me5)2UCl2 are no longer degenerate, and fall in two distinct energy groupings. The 5f-orbitals are lowest in energy and split into a 5-over-2 pattern with the high lying U 6d-orbitals split in a 4-over-1 pattern, the latter of which is similar to the dorbital splitting in group IV transition metal (C5R5)2MCl2 (R = H, Me) compounds. Time dependent-DFT (TD-DFT) was used to calculate the energies and intensities of Cl 1s transitions into empty metal based orbitals containing Cl 3p character, and provide simulated Cl K-edge XAS spectra for 1 - 4. However, for 5, which has two unpaired electrons, analogous information was obtained from transition dipole calculations using ground state Kohn-Sham orbitals. The simulations provide additional confidence in the interpretation of spectra based on ground state calculations. Overall, this study demonstrates that Cl K-edge XAS and DFT calculations represent powerful tools that can be used to evaluate electronic structure and covalency in actinide metal-ligand bonding. In addition, these results provide a framework that can be used in future studies to evaluate actinide covalency in compounds that contain transuranic elements.

  8. X Ray Precursors in SGRs: Precessing Gamma Jet Tails

    E-Print Network [OSTI]

    Daniele Fargion

    2001-05-18

    Weak isolated X-ray precursor events before the main Gamma Ray Burst, GRB, and also rare Soft Gamma Repeaters, SGR, events are in complete disagreement with any Fireball, or Magnetar, one-shoot explosive scenarios. Fireball model in last two years has been deeply modified into a fountain beamed Jet exploding and interacting on external shells to explain GRB fine time structure. On the contrary earlier we proposed a unified scenario for both GRBs-SGRs where a precessing Gamma Jet (of different intensity) and its geometrical beaming is the source of both GRB and SGRs wide morphology. GRBs are peaked SNs Jet spinning and precessing observed along the thin Jet axis. Their mysterious weak X precursors bursts, corresponding to non-negligible energy powers, up to million Supernova ones for GRB, are gamma Jet tails beamed off-axis, observed at X-Ray tails. They are rare, about (3-6)% of all GRBs, but not unique at all. Comparable brief X-ray precursor flashes occurred in rarest and most detailed SGRs events as the 27 and the 29 August 1998 event from SGR 1900+14. The same source has been in very power-full activity on recent 18 April 2001 once again preceded by X-Ray precursors. These events are inconsistent with any Fireball or Magnetar-Mini-Fireball models. We interpret them naturally as earlier marginal blazing of outlying X conical precessing Jet, an off-axis tails surrounding a narrower gamma precessing Jet. Only when the light-house Jet is in on-axis blazing mode toward the Earth we observe the harder power-full SGR event. We predict such a rich X-Ray precursor signals (more numerous then gamma ones) during Soft Gamma Repeater peak activities; they should be abundant and within detection threshold by a permanent monitoring SGRs by Beppo-Sax WFC or Chandra X ray satellites while at peak activity.

  9. Evidence Against BALS in the X-ray Bright QSO PG1416-129

    E-Print Network [OSTI]

    Paul J. Green; Thomas L. Aldcroft; Smita Mathur; Norbert Schartel

    1997-02-24

    Recent results from the ROSAT All Sky Survey, and from deep ROSAT pointings reveal that broad absorption line quasars (BALQSOs) are weak in the soft X-ray bandpass (with optical-to-X-ray spectral slope alpha_{ox}>1.8) in comparison to QSOs with normal OUV spectra (mean alpha_{ox}=1.4). One glaring exception appeared to be the nearby BALQSO PG1416-129, which is a bright ROSAT source showing no evidence for intrinsic soft X-ray absorption. We present here our new HST FOS spectrum of PG1416-129, in which we find no evidence for BALs. We show that the features resulting in the original BAL classification, based on IUE spectra, were probably spurious. On the basis of UV, X-ray and optical evidence, we conclude that PG1416-129, is not now, and has never been a BALQSO. Our result suggests that weak soft X-ray emission is a defining characteristic of true BALQSOs. If BALQSOs indeed harbor normal intrinsic spectral energy distributions, their observed soft X-ray weakness is most likely the result of absorption. The ubiquitous occurrence of weak soft X-ray emission with UV absorption (BALs) thus suggests absorbers in each energy regime that are physically associated, if not identical.

  10. X-ray photoemission electron microscopy for the study of semiconductor materials

    SciTech Connect (OSTI)

    Anders, S.; Stammler, T.; Padmore, H.; Terminello, L.J.; Jankowski, A.F.; Stohr, J.; Diaz, J.; Cossy-Gantner, A.

    1998-03-01

    Photoemission Electron Microscopy (PEEM) using X-rays is a novel combination of two established materials analysis techniques--PEEM using UV light, and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. This combination allows the study of elemental composition and bonding structure of the sample by NEXAFS spectroscopy with a high spatial resolution given by the microscope. A simple, two lens, 10 kV operation voltage PEEM has been used at the Stanford Synchrotron Radiation Laboratory and at the Advanced Light Source (ALS) in Berkeley to study various problems including materials of interest for the semiconductor industry. In the present paper the authors give a short overview over the method and the instrument which was used, and describe in detail a number of applications. These applications include the study of the different phases of titanium disilicide, various phases of boron nitride, and the analysis of small particles. A brief outlook is given on possible new fields of application of the PEEM technique, and the development of new PEEM instruments.

  11. Detailed Characterization of a Nanosecond-Lived Excited State: X-ray and Theoretical Investigation of the Quintet State in Photoexcited [Fe(terpy) 2 ] 2+

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Vankó, György; Bordage, Amélie; Pápai, Mátyás; Haldrup, Kristoffer; Glatzel, Pieter; March, Anne Marie; Doumy, Gilles; Britz, Alexander; Galler, Andreas; Assefa, Tadesse; et al

    2015-03-19

    Theoretical predictions show that depending on the populations of the Fe 3dxy, 3dxz, and 3dyz orbitals two possible quintet states can exist for the high-spin state of the photoswitchable model system [Fe(terpy)2]2+. The differences in the structure and molecular properties of these 5B2 and 5E quintets are very small and pose a substantial challenge for experiments to resolve them. Yet for a better understanding of the physics of this system, which can lead to the design of novel molecules with enhanced photoswitching performance, it is vital to determine which high-spin state is reached in the transitions that follow the lightmore »excitation. The quintet state can be prepared with a short laser pulse and can be studied with cutting-edge time-resolved X-ray techniques. Here we report on the application of an extended set of X-ray spectroscopy and scattering techniques applied to investigate the quintet state of [Fe(terpy)2]2+ 80 ps after light excitation. High-quality X-ray absorption, nonresonant emission, and resonant emission spectra as well as X-ray diffuse scattering data clearly reflect the formation of the high-spin state of the [Fe(terpy)2]2+ molecule; moreover, extended X-ray absorption fine structure spectroscopy resolves the Fe–ligand bond-length variations with unprecedented bond-length accuracy in time-resolved experiments. With ab initio calculations we determine why, in contrast to most related systems, one configurational mode is insufficient for the description of the low-spin (LS)–high-spin (HS) transition. We identify the electronic structure origin of the differences between the two possible quintet modes, and finally, we unambiguously identify the formed quintet state as 5E, in agreement with our theoretical expectations.« less

  12. X-ray emission from O stars

    E-Print Network [OSTI]

    David H. Cohen

    2008-02-01

    Young O stars are strong, hard, and variable X-ray sources, properties which strongly affect their circumstellar and galactic environments. After ~1 Myr, these stars settle down to become steady sources of soft X-rays. I use high-resolution X-ray spectroscopy and MHD modeling to show that young O stars like theta-1 Ori C are well explained by the magnetically channeled wind shock scenario. After their magnetic fields dissipate, older O stars produce X-rays via shock heating in their unstable stellar winds. Here too I use X-ray spectroscopy and numerical modeling to confirm this scenario. In addition to elucidating the nature and cause of the O star X-ray emission, modeling of the high-resolution X-ray spectra of O supergiants provides strong evidence that mass-loss rates of these O stars have been overestimated.

  13. X-ray Imaging Workshop

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWindX-Ray ImagingInImaging and

  14. Soft X-ray techniques to study mesoscale magnetism

    E-Print Network [OSTI]

    Kortright, Jeffrey B.

    2003-01-01

    X-Ray Techniques to Study Mesoscale Magnetism Jeffrey B.X-Ray Techniques to Study Mesoscale Magnetism Jeffrey B.

  15. X-ray transmissive debris shield

    DOE Patents [OSTI]

    Spielman, Rick B. (Albuquerque, NM)

    1994-01-01

    A composite window structure is described for transmitting x-ray radiation and for shielding radiation generated debris. In particular, separate layers of different x-ray transmissive materials are laminated together to form a high strength, x-ray transmissive debris shield which is particularly suited for use in high energy fluences. In one embodiment, the composite window comprises alternating layers of beryllium and a thermoset polymer.

  16. X-ray microscopy. Beyond ensemble averages

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ice, Gene E.; Budai, John D.

    2015-06-23

    This work exemplifies emerging tools to characterize local materials structure and dynamics, made possible by powerful X-ray synchrotron and transmission electron microscopy methods.

  17. X-ray laser microscope apparatus

    DOE Patents [OSTI]

    Suckewer, Szymon (Princeton, NJ); DiCicco, Darrell S. (Plainsboro, NJ); Hirschberg, Joseph G. (Coral Gables, FL); Meixler, Lewis D. (East Windsor, NJ); Sathre, Robert (Princeton, NJ); Skinner, Charles H. (Lawrenceville, NJ)

    1990-01-01

    A microscope consisting of an x-ray contact microscope and an optical microscope. The optical, phase contrast, microscope is used to align a target with respect to a source of soft x-rays. The source of soft x-rays preferably comprises an x-ray laser but could comprise a synchrotron or other pulse source of x-rays. Transparent resist material is used to support the target. The optical microscope is located on the opposite side of the transparent resist material from the target and is employed to align the target with respect to the anticipated soft x-ray laser beam. After alignment with the use of the optical microscope, the target is exposed to the soft x-ray laser beam. The x-ray sensitive transparent resist material whose chemical bonds are altered by the x-ray beam passing through the target mater GOVERNMENT LICENSE RIGHTS This invention was made with government support under Contract No. De-FG02-86ER13609 awarded by the Department of Energy. The Government has certain rights in this invention.

  18. Compound refractive X-ray lens

    DOE Patents [OSTI]

    Nygren, David R. (Berkeley, CA); Cahn, Robert (Walnut Creek, CA); Cederstrom, Bjorn (Traellborg, SE); Danielsson, Mats (Stocksund, SE); Vestlund, Jonas (Stockholm, SE)

    2000-01-01

    An apparatus and method for focusing X-rays. In one embodiment, his invention is a commercial-grade compound refractive X-ray lens. The commercial-grade compound refractive X-ray lens includes a volume of low-Z material. The volume of low-Z material has a first surface which is adapted to receive X-rays of commercially-applicable power emitted from a commercial-grade X-ray source. The volume of low-Z material also has a second surface from which emerge the X-rays of commercially-applicable power which were received at the first surface. Additionally, the commercial-grade compound refractive X-ray lens includes a plurality of openings which are disposed between the first surface and the second surface. The plurality of openings are oriented such that the X-rays of commercially-applicable power which are received at the first surface, pass through the volume of low-Z material and through the plurality openings. In so doing, the X-rays which emerge from the second surface are refracted to a focal point.

  19. X-Ray Nanoimaging: Instruments and Methods

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAbout /Two0PhotosPresentationsWorld's largestX-RayX-RayX-RayX-Ray

  20. X-ray spectroscopy of neutron star low-mass X-ray binaries

    E-Print Network [OSTI]

    Krauss, Miriam Ilana

    2007-01-01

    In this thesis, I present work spanning a variety of topics relating to neutron star lowmass X-ray binaries (LMXBs) and utilize spectral information from X-ray observations to further our understanding of these sources. ...

  1. Phased Contrast X-Ray Imaging

    ScienceCinema (OSTI)

    Erin Miller

    2012-12-31

    The Pacific Northwest National Laboratory is developing a range of technologies to broaden the field of explosives detection. Phased contrast X-ray imaging, which uses silicon gratings to detect distortions in the X-ray wave front, may be applicable to mail or luggage scanning for explosives; it can also be used in detecting other contraband, small-parts inspection, or materials characterization.

  2. X-ray Microspectroscopy and Chemical Reactions in Soil Microsites

    SciTech Connect (OSTI)

    D Hesterberg; M Duff; J Dixon; M Vepraskas

    2011-12-31

    Soils provide long-term storage of environmental contaminants, which helps to protect water and air quality and diminishes negative impacts of contaminants on human and ecosystem health. Characterizing solid-phase chemical species in highly complex matrices is essential for developing principles that can be broadly applied to the wide range of notoriously heterogeneous soils occurring at the earth's surface. In the context of historical developments in soil analytical techniques, we describe applications of bulk-sample and spatially resolved synchrotron X-ray absorption spectroscopy (XAS) for characterizing chemical species of contaminants in soils, and for determining the uniqueness of trace-element reactivity in different soil microsites. Spatially resolved X-ray techniques provide opportunities for following chemical changes within soil microsites that serve as highly localized chemical micro- (or nano-)reactors of unique composition. An example of this microreactor concept is shown for micro-X-ray absorption near edge structure analysis of metal sulfide oxidation in a contaminated soil. One research challenge is to use information and principles developed from microscale soil chemistry for predicting macroscale and field-scale behavior of soil contaminants.

  3. X-rays from Hot Subdwarfs

    E-Print Network [OSTI]

    Mereghetti, Sandro

    2015-01-01

    Thanks to the high sensitivity of the instruments on board the XMM-Newton and Chandra satellites, it has become possible to explore the properties of the X-ray emission from hot subdwarfs. The small but growing sample of hot subdwarfs detected in X-rays includes binary systems, in which the X-rays result from wind accretion onto a compact companion (white dwarf or neutron star), as well as isolated sdO stars in which X-rays are probably due to shock instabilities in the wind. X-ray observations of these low mass stars provide information which can be useful also for our understanding of the winds of more luminous and massive early-type stars and can lead to the discovery of particularly interesting binary systems.

  4. High Energy Vision: Processing X-rays

    E-Print Network [OSTI]

    DePasquale, Joseph; Edmonds, Peter

    2015-01-01

    Astronomy is by nature a visual science. The high quality imagery produced by the world's observatories can be a key to effectively engaging with the public and helping to inspire the next generation of scientists. Creating compelling astronomical imagery can, however, be particularly challenging in the non-optical wavelength regimes. In the case of X-ray astronomy, where the amount of light available to create an image is severely limited, it is necessary to employ sophisticated image processing algorithms to translate light beyond human vision into imagery that is aesthetically pleasing while still being scientifically accurate. This paper provides a brief overview of the history of X-ray astronomy leading to the deployment of NASA's Chandra X-ray Observatory, followed by an examination of the specific challenges posed by processing X-ray imagery. The authors then explore image processing techniques used to mitigate such processing challenges in order to create effective public imagery for X-ray astronomy. ...

  5. X-ray absorption studies of mixed salt polymer electrolytes: ZnBr{sub 2}/CaBr{sub 2}-PEO, ZnBr{sub 2}/LiBr-PEO, and ZnBr{sub 2}/RbBr-PEO complexes

    SciTech Connect (OSTI)

    McBreen, J.; Yang, X.Q.; Lee, H.S.; Okamoto, Y.

    1995-02-01

    Polyethylene oxide (PEO)-salt systems are an important new class of electrolytes that are being considered for many uses. X-ray absorption (XAS) studies of ZnBr{sub 2}-PEO complexes, at the Zn K edge, at temperatures between 25 and 120 C, indicate that additions of bromide salts of Li, Rb, or Ca result in the formation of ZnBr{sub 4}{sup {minus} 2} complexes with a Zn-Br bond length of 2.42 {angstrom}. XAS, at the Rb K edge, in mixed RbBr/ZnBr{sub 2}-PEO complexes with an excess of ZnBr{sub 2}, shows that the ZnBr{sub 2} causes the RbBr to dissolve in the polymer. The Rb{sup +} ions are weakly complexed with the PEO with an Rb-O bond distance of 2.93 {angstrom}.

  6. X-ray reflection spectra from ionized slabs

    E-Print Network [OSTI]

    R. R. Ross; A. C. Fabian; A. J. Young

    1999-02-23

    X-ray reflection spectra are an important component in the X-ray spectra of many active galactic nuclei and Galactic black hole candidates. It is likely that reflection takes place from highly ionized surfaces of the accretion disc in some cases. This can lead to strong Comptonization of the emergent iron, and other, absorption and emission features. We present such reflection spectra here, computed in a self-consistent manner with the method described by Ross and Fabian. In particular we emphasise the range where the ionization parameter (the flux to density ratio) \\xi is around and above 10^4. Such spectra may be relevant to the observed spectral features found in black hole candidates such as Cygnus X-1 in the low/hard state.

  7. X-rays only when you want them: Optimized pump–probe experiments using pseudo-single-bunch operation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hertlein, M. P.; Scholl, A.; Cordones, A. A.; Lee, J. H.; Engelhorn, K.; Glover, T. E.; Barbrel, B.; Sun, C.; Steier, C.; Portmann, G.; et al

    2015-04-02

    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 experimental setup and allowing the investigation of less robust samples. Single-shotmore »X-ray exposures of a streak camera detector using a conventional non-gated charge-coupled device (CCD) camera are also demonstrated.« less

  8. X-ray Spectral Survey of WGACAT Quasars, II: Optical and Radio Properties of Quasars with Low Energy X-ray Cut-offs

    E-Print Network [OSTI]

    Martin Elvis; Fabrizio Fiore; Paolo Giommi; Paolo Padovani

    1997-08-05

    We have selected quasars with X-ray colors suggestive of a low energy cut-off, from the ROSAT PSPC pointed archive. We examine the radio and optical properties of these 13 quasars. Five out of the seven quasars with good optical spectra show associated optical absorption lines, with two having high delta-v candidate systems. Two other cut-off quasars show reddening associated with the quasar. We conclude that absorption is highly likely to be the cause of the X-ray cut-offs, and that the absorbing material associated with the quasars, not intervening along the line-of-sight. The suggestion that Gigahertz Peaked Sources are associated with X-ray cut-offs remains unclear with this expanded sample.

  9. X-ray phase-contrast methods

    SciTech Connect (OSTI)

    Lider, V. V., E-mail: lider@ns.crys.ras.ru; Kovalchuk, M. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2013-11-15

    This review is devoted to a comparative description of the methods for forming X-ray phase-contrast images of weakly absorbing (phase) objects. These include the crystal interferometer method, the Talbot interferometer method, diffraction-enhanced X-ray imaging, and the in-line method. The potential of their practical application in various fields of science and technology is discussed. The publications on the development and optimization of X-ray phase-contrast methods and the experimental study of phase objects are analyzed.

  10. X-rays Illuminate Ancient Archimedes Text

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWindX-RayX-RayX-ray

  11. Optical Identification of the Hardest X-ray Source in the ASCA Large Sky Survey

    E-Print Network [OSTI]

    M. Akiyama; K. Ohta; T. Yamada; M. Eracleous; J. P. Halpern; N. Kashikawa; M. Yagi; W. Kawasaki; M. Sakano; T. Tsuru; Y. Ueda; T. Takahashi

    1998-01-18

    We report the optical identification of the hardest X-ray source (AX J131501+3141) detected in an unbiased wide-area survey in the 0.5--10 keV band, the ASCA Large Sky Survey. The X-ray spectrum of the source is very hard and is well reproduced by a power-law component (Gamma = 1.5^+0.7_-0.6) with N_H = 6^+4_-2 *10^22 cm^-2 (Sakano et al. 1998). We have found a galaxy with R=15.62 mag near the center of the error circle for the X-ray source. The optical spectrum of the galaxy shows only narrow emission lines whose ratios correspond to those of a type 2 Seyfert galaxy at z = 0.072, implying an absorption-corrected X-ray luminosity of 2*10^43 erg sec^-1 (2--10 keV) and M_B = -20.93 mag. A radio point source is also associated with the center of the galaxy. We thus identify the X-ray source with this galaxy as an obscured AGN. The hidden nature of the nucleus of the galaxy in the optical band is consistent with the X-ray spectrum. These results support the idea that the obscured AGNs/QSOs contribute significantly to the cosmic X-ray background in the hard band at the faint flux level.

  12. Phase-contrast imaging using ultrafast x-rays in laser-shocked materials

    SciTech Connect (OSTI)

    Workman, Jonathan B; Cobble, James A; Flippo, Kirk; Gautier, Donald C; Montgomery, David S; Offermann, Dustin T

    2010-01-01

    High-energy x-rays, > 10-keV, can be efficiently produced from ultrafast laser target interactions with many applications to dense target materials in Inertial Confinement Fusion (ICF) and High-Energy Density Physics (HEDP). These same x-rays can also be applied to measurements of low-density materials inside high-density hohlraum environments. In the experiments presented, high-energy x-ray images of laser-shocked polystyrene are produced through phase contrast imaging. The plastic targets are nominally transparent to traditional x-ray absorption but show detailed features in regions of high density gradients due to refractive effects often called phase contrast imaging. The 200-TW Trident laser is used both to produce the x-ray source and to shock the polystyrene target. X-rays at 17-keV produced from 2-ps, 100-J laser interactions with a 12-micron molybdenum wire are used to produce a small source size, required for optimizing refractive effects. Shocks are driven in the 1-mm thick polystyrene target using 2-ns, 250-J, 532-nm laser drive with phase plates. X-ray images of shocks compare well to 1-D hydro calculations, HELIOS-CR.

  13. Applications of x-ray synchrotron radiation techniques to the study of dispersed electrocatalysts in high area materials

    SciTech Connect (OSTI)

    McBreen, J.

    1991-12-31

    This report discusses work demonstrating that X-Ray Absorption Spectroscopy is a very powerful technique for the study of electrocatalysts. Results for a prototech catalyst, and platinum are presented. (JL)

  14. Applications of x-ray synchrotron radiation techniques to the study of dispersed electrocatalysts in high area materials

    SciTech Connect (OSTI)

    McBreen, J.

    1991-01-01

    This report discusses work demonstrating that X-Ray Absorption Spectroscopy is a very powerful technique for the study of electrocatalysts. Results for a prototech catalyst, and platinum are presented. (JL)

  15. Measuring the efficacy of a root biobarrier with x-ray computed tomography

    SciTech Connect (OSTI)

    Tollner, E.W.; Murphy, C.E. Jr. . Dept. of Agricultural Engineering)

    1990-08-16

    X-ray computed tomography is a useful tool for investigating soil physical properties nondestructively. There is a need to develop proper calibration relationships between soil properties and the x-ray absorption coefficient. The objective of the work was to evaluate soil factors affecting the x-ray absorption coefficient. Based on a theoretical analysis, experimental data from five soils and on results of several other investigators, it was concluded that for many applications, one calibration relationship is applicable to a wide range of soils. The montmorillinitic clay used in the study required special handling due to the extreme shrinkage of this soil upon drying. Knowledge of chemical composition enables approximations but not exact predictions of the x-ray absorption coefficient. The results suggested some reasonable alternative to exhaustive calibration for each anticipated soil condition. Quantification of root activity in terms of root growth and indirectly through water uptake is necessary for understanding plant growth dynamics. X-ray computed tomography (CT) enables qualitative as well as two quantitative outputs, one of which can lead to conclusions regarding root activity. A greenhouse study involving soil columns (Lakeland sand, bulk density 1.4 Mg/m{sup 3}) planted to soybean, Bahiagras, and control (no vegetation) was conducted in 1989. A treflan based on chemical barrier was placed in half of the soil column of each species. The mean x-ray absorption correlated to water content. Results suggested that root presence can also be indirectly inferred based on water content drawn down during planned stress events. It was concluded that x-ray CT may have a niche in soil-water-plant relation studies, particularly when plant species have large roots. 35 refs., 13 figs., 8 tabs.

  16. Small Angle X-Ray Scattering Detector

    DOE Patents [OSTI]

    Hessler, Jan P.

    2004-06-15

    A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., qmax/qmin approx=lO0.

  17. X-Ray Nanoimaging: Instruments and Methods

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Instruments and Methods X-Ray Nanoimaging: Instruments and Methods Print To be held as part of SPIE. http:spie.orgOP318 August 28-29, 2013; San Diego, California, USA...

  18. X-ray source for mammography

    DOE Patents [OSTI]

    Logan, Clinton M. (Pleasanton, CA)

    1994-01-01

    An x-ray source utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms.

  19. X-ray source for mammography

    DOE Patents [OSTI]

    Logan, C.M.

    1994-12-20

    An x-ray source is described utilizing anode material which shifts the output spectrum to higher energy and thereby obtains higher penetrating ability for screening mammography application, than the currently utilized anode material. The currently used anode material (molybdenum) produces an energy x-ray spectrum of 17.5/19.6 keV, which using the anode material of this invention (e.g. silver, rhodium, and tungsten) the x-ray spectrum would be in the 20-35 keV region. Thus, the anode material of this invention provides for imaging of breasts with higher than average x-ray opacity without increase of the radiation dose, and thus reduces the risk of induced breast cancer due to the radiation dose administered for mammograms. 6 figures.

  20. Compton backscattered collmated X-ray source

    DOE Patents [OSTI]

    Ruth, Ronald D. (Woodside, CA); Huang, Zhirong (Stanford, CA)

    2000-01-01

    A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

  1. Compton backscattered collimated x-ray source

    DOE Patents [OSTI]

    Ruth, R.D.; Huang, Z.

    1998-10-20

    A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

  2. Compton backscattered collimated x-ray source

    DOE Patents [OSTI]

    Ruth, Ronald D. (Woodside, CA); Huang, Zhirong (Stanford, CA)

    1998-01-01

    A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

  3. X-ray laser driven gold targets

    SciTech Connect (OSTI)

    Petrova, Tz. B., E-mail: lina.petrova@nrl.navy.mil; Whitney, K. G.; Davis, J. [Plasma Physics Division, Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375 (United States)] [Plasma Physics Division, Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375 (United States)

    2014-03-15

    The femtosecond population dynamics of gold irradiated by a coherent high-intensity (>10{sup 17}?W/cm{sup 2}) x-ray laser pulse is investigated theoretically. There are two aspects to the assembled model. One is the construction of a detailed model of platinum-like gold inclusive of all inner-shell states that are created by photoionization of atomic gold and decay either by radiative or Auger processes. Second is the computation of the population dynamics that ensues when an x-ray pulse is absorbed in gold. The hole state generation depends on the intensity and wavelength of the driving x-ray pulse. The excited state populations reached during a few femtosecond timescales are high enough to generate population inversions, whose gain coefficients are calculated. These amplified lines in the emitted x-ray spectrum provide important diagnostics of the radiation dynamics and also suggest a nonlinear way to increase the frequency of the coherent output x-ray pulses relative to the frequency of the driver input x-ray pulse.

  4. Transient x-ray diffraction and its application to materials science and x-ray optics

    SciTech Connect (OSTI)

    Hauer, A.A.; Kopp, R.; Cobble, J.; Kyrala, G.; Springer, R.

    1997-12-01

    Time resolved x-ray diffraction and scattering have been applied to the measurement of a wide variety of physical phenomena from chemical reactions to shock wave physics. Interest in this method has heightened in recent years with the advent of versatile, high power, pulsed x-ray sources utilizing laser plasmas, electron beams and other methods. In this article, we will describe some of the fundamentals involved in time resolved x-ray diffraction, review some of the history of its development, and describe some recent progress in the field. In this article we will emphasize the use of laser-plasmas as the x-ray source for transient diffraction.

  5. Differential phase contrast X-ray imaging system and components

    DOE Patents [OSTI]

    Stutman, Daniel; Finkenthal, Michael

    2014-07-01

    A differential phase contrast X-ray imaging system includes an X-ray illumination system, a beam splitter arranged in an optical path of the X-ray illumination system, and a detection system arranged in an optical path to detect X-rays after passing through the beam splitter.

  6. Pyroelectric crystal-based X-ray diffractometer

    E-Print Network [OSTI]

    Fernandes, Louis Edward

    2007-01-01

    We investigate the use of an Amptek Cool-X X-ray Generator for an instructional tool in the physics of x-rays, as well as a source for x-rays for crystal diffraction experiments. The x-ray source is a solid-state two-phase ...

  7. RR Pic (1925): A Chandra X-ray View

    E-Print Network [OSTI]

    Y. Pekon; S. Balman

    2008-05-20

    We present the Chandra ACIS-S3 data of the old classical nova RR Pic (1925). The source has a count rate of 0.067+/-0.002 c/s in the 0.3-5.0 keV energy range. We detect the orbital period of the underlying binary system in the X-ray wavelengths. We also find that the neutral Hydrogen column density differs for orbital minimum and orbital maximum spectra with values 0.25(+0.23-0.18)x10^22 cm^-2 and 0.64(+0.13-0.14)x10^22 cm^-2 at 3sigma confidence level. The X-ray spectrum of RR Pic can be represented by a composite model of bremsstrahlung with a photoelectric absorption, two absorption lines centered around 1.1-1.4 keV and 5 Gaussian lines centered at emission lines around 0.3-1.1 keV corresponding to various transitions of S, N, O, C, Ne and Fe . The bremsstrahlung temperature derived from the fits range from 0.99 to 1.60 keV and the unabsorbed X-ray flux is found to be 2.5(+0.4-1.2)x10^-13 erg cm^-2 s^-1 in the 0.3-5.0 keV range with a luminosity of (1.1\\pm0.2)x10^31 erg s^-1 at 600 pc. We also detect excess emission in the spectrum possibly originating from the reverse shock in the ejecta.

  8. Ultrafast X-Ray Coherent Control

    SciTech Connect (OSTI)

    Reis, David

    2009-05-01

    This main purpose of this grant was to develop the nascent #12;eld of ultrafast x-ray science using accelerator-based sources, and originally developed from an idea that a laser could modulate the di#11;racting properties of a x-ray di#11;racting crystal on a fast enough time scale to switch out in time a shorter slice from the already short x-ray pulses from a synchrotron. The research was carried out primarily at the Advanced Photon Source (APS) sector 7 at Argonne National Laboratory and the Sub-Picosecond Pulse Source (SPPS) at SLAC; in anticipation of the Linac Coherent Light Source (LCLS) x-ray free electron laser that became operational in 2009 at SLAC (all National User Facilities operated by BES). The research centered on the generation, control and measurement of atomic-scale dynamics in atomic, molecular optical and condensed matter systems with temporal and spatial resolution . It helped develop the ultrafast physics, techniques and scienti#12;c case for using the unprecedented characteristics of the LCLS. The project has been very successful with results have been disseminated widely and in top journals, have been well cited in the #12;eld, and have laid the foundation for many experiments being performed on the LCLS, the world's #12;rst hard x-ray free electron laser.

  9. Oscillations During Thermonuclear X-ray Bursts

    E-Print Network [OSTI]

    Tod E. Strohmayer

    2001-01-12

    High amplitude, nearly coherent X-ray brightness oscillations during thermonuclear X-ray bursts were discovered with the Rossi X-ray Timing Explorer (RXTE) in early 1996. Spectral and timing evidence strongly supports the conclusion that these oscillations are caused by rotational modulation of the burst emission and that they reveal the spin frequency of neutron stars in low mass X-ray binaries, a long sought goal of X-ray astronomy. Studies carried out over the past year have led to the discovery of burst oscillations in four new sources, bringing to ten the number with confirmed burst oscillations. I review the status of our knowledge of these oscillations and indicate how they can be used to probe the physics of neutron stars. For a few burst oscillation sources it has been proposed that the strongest and most ubiquitous frequency is actually the first overtone of the spin frequency and hence that two nearly antipodal hot spots are present on the neutron star. This inference has important implications for both the physics of thermonuclear burning as well as the mass - radius relation for neutron stars, so its confirmation is crucial. I discuss recent attempts to confirm this hypothesis for 4U 1636-53, the source for which a signal at the putative fundamental (290 Hz) has been claimed.

  10. X-ray lithography using holographic images

    DOE Patents [OSTI]

    Howells, M.S.; Jacobsen, C.

    1997-03-18

    Methods for forming X-ray images having 0.25 {micro}m minimum line widths on X-ray sensitive material are presented. A holographic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required. 15 figs.

  11. In Operando X-ray Diffraction and Transmission X-ray Microscopy of Lithium Sulfur Batteries

    E-Print Network [OSTI]

    Cui, Yi

    In Operando X-ray Diffraction and Transmission X-ray Microscopy of Lithium Sulfur Batteries Johanna Information ABSTRACT: Rechargeable lithium-sulfur (Li-S) batteries hold great potential for high not well understood. In this Article, these changes in Li-S batteries are studied in operando by X

  12. X-Ray Data from the X-Ray Data Booklet Online

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Thompson, Albert C.; Attwood, David T.; Gullikson, Eric M.; Howells, Malcolm R.; Kortright, Jeffrey B.; Robinson, Arthur L.; Underwood, James H.; Kim, Kwang-Je; Kirz, Janos; Lindau, Ingolf; Pianetta, Piero; Winick, Herman; Williams, Gwyn P.; Scofield, James H.

    The original X-Ray Data Booklet, published in 1985, became a classic reference source. The online version has been significantly revised and updated to reflect today's science. Hundreds of pages of authoritative data provide the x-ray properties of elements, information on synchrotron radiation, scattering processes, optics and detectors, and other related calculations, formulas, and data tables.

  13. X-ray Point Source Populations Constituting the Galactic Ridge X-ray Emission

    E-Print Network [OSTI]

    Morihana, Kumiko; Yoshida, Tessei; Ebisawa, Ken

    2013-01-01

    Apparently diffuse X-ray emission has been known to exist along the central quarter of the Galactic Plane since the beginning of the X-ray astronomy, which is referred to as the Galactic Ridge X-ray emission (GRXE). Recent deep X-ray observations have shown that numerous X-ray point sources account for a large fraction of the GRXE in the hard band (2-8 keV). However, the nature of these sources is poorly understood. Using the deepest X-ray observations made in the Chandra Bulge Field (Revnivtsev et al., 2009,2011), we present the result of a coherent photometric and spectroscopic analysis of individual X-ray point sources for the purpose of constraining their nature and deriving their fractional contributions to the hard band continuum and Fe K\\alpha line emission of the GRXE. Based on the X-ray color-color diagram, we divided the point sources into three groups: A (hard), B (soft and broad spectrum), and C (soft and peaked spectrum). The group A sources are further decomposed spectrally into thermal and non-...

  14. Mapping Metals Incorporation of a Whole Single Catalyst Particle Using Element Specific X-ray Nanotomography

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Meirer, Florian; Morris, Darius T.; Kalirai, Sam; Liu, Yijin; Andrews, Joy C.; Weckhuysen, Bert M.

    2015-01-02

    Full-field transmission X-ray microscopy has been used to determine the 3D structure of a whole individual fluid catalytic cracking (FCC) particle at high spatial resolution and in a fast, noninvasive manner, maintaining the full integrity of the particle. Using X-ray absorption mosaic imaging to combine multiple fields of view, computed tomography was performed to visualize the macropore structure of the catalyst and its availability for mass transport. We mapped the relative spatial distributions of Ni and Fe using multiple-energy tomography at the respective X-ray absorption K-edges and correlated these distributions with porosity and permeability of an equilibrated catalyst (E-cat) particle.more »Both metals were found to accumulate in outer layers of the particle, effectively decreasing porosity by clogging of pores and eventually restricting access into the FCC particle.« less

  15. Mapping Metals Incorporation of a Whole Single Catalyst Particle Using Element Specific X-ray Nanotomography

    SciTech Connect (OSTI)

    Meirer, Florian; Morris, Darius T.; Kalirai, Sam; Liu, Yijin; Andrews, Joy C.; Weckhuysen, Bert M.

    2015-01-02

    Full-field transmission X-ray microscopy has been used to determine the 3D structure of a whole individual fluid catalytic cracking (FCC) particle at high spatial resolution and in a fast, noninvasive manner, maintaining the full integrity of the particle. Using X-ray absorption mosaic imaging to combine multiple fields of view, computed tomography was performed to visualize the macropore structure of the catalyst and its availability for mass transport. We mapped the relative spatial distributions of Ni and Fe using multiple-energy tomography at the respective X-ray absorption K-edges and correlated these distributions with porosity and permeability of an equilibrated catalyst (E-cat) particle. Both metals were found to accumulate in outer layers of the particle, effectively decreasing porosity by clogging of pores and eventually restricting access into the FCC particle.

  16. Thermal and Nonthermal X-Ray Emission in SNR RCW 86

    E-Print Network [OSTI]

    K. J. Borkowski; J. Rho; S. P. Reynolds; K. K. Dyer

    2000-06-10

    Supernova remnants may exhibit both thermal and nonthermal X-ray emission. Such remnants can be distinguished by the weakness of their X-ray lines, because of the presence of a strong nonthermal X-ray continuum. RCW 86 is a remnant with weak lines, resulting in low and peculiar abundances when thermal models alone are used to interpret its X-ray spectrum. This indicates the presence of a strong nonthermal synchrotron continuum. We analyze ASCA X-ray spectra of RCW 86 with the help of both nonequilibrium ionization thermal models and nonthermal synchrotron models. A two-temperature thermal model and a simple nonthermal model with an exponential cutoff (plus interstellar absorption) give reasonable results. We obtain blast wave velocity of 800 km/s, the shock ionization age of 1-3x10^11 s/cm^3, and the break in nonthermal spectra at 2-4x10^16 Hz. The strength of nonthermal continuum correlates well with the radio brightness in the bright SW section of the remnant. This is convincing evidence for X-ray synchrotron emission in RCW 86.

  17. Femtosecond X-ray Absorption Spectroscopy at a Hard X-ray Free Electron

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journal Article) |production at aSciTech Connect Fe AtomicSciTechLaser: Application

  18. X-ray Clusters at High Redshift

    E-Print Network [OSTI]

    I. M. Gioia

    1997-11-30

    As the largest gravitationally bound structures known, clusters provide clear constraints on the formation of structure and on the composition of the universe. Despite their extreme importance for cosmology the number of clusters at high redshift (z > 0.75) is rather small. There are only a few X-ray emitting examples reported and a handful of optically-selected ones. These clusters can provide stringent constrains on theories of large scale structure formation, if they are massive enough. I will review the status of these distant X-ray selected clusters. These objects are of special importance because their X-ray emission implies that they are massive, comparable to low redshift examples, and their existence is problematic for some theories of structure formation.

  19. Radiobiological studies using gamma and x rays.

    SciTech Connect (OSTI)

    Potter, Charles Augustus; Longley, Susan W.; Scott, Bobby R. [Lovelace Respiratory Research Institute, Albuquerque, NM; Lin, Yong [Lovelace Respiratory Research Institute, Albuquerque, NM; Wilder, Julie [Lovelace Respiratory Research Institute, Albuquerque, NM; Hutt, Julie A. [Lovelace Respiratory Research Institute, Albuquerque, NM; Padilla, Mabel T. [Lovelace Respiratory Research Institute, Albuquerque, NM; Gott, Katherine M. [Lovelace Respiratory Research Institute, Albuquerque, NM

    2013-02-01

    There are approximately 500 self-shielded research irradiators used in various facilities throughout the U.S. These facilities use radioactive sources containing either 137Cs or 60Co for a variety of biological investigations. A report from the National Academy of Sciences[1] described the issues with security of particular radiation sources and the desire for their replacement. The participants in this effort prepared two peer-reviewed publications to document the results of radiobiological studies performed using photons from 320-kV x rays and 137Cs on cell cultures and mice. The effectiveness of X rays was shown to vary with cell type.

  20. Lensless X-Ray Imaging in Reflection

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse Bergkamp GraduateResidentialLensless Imaging of WholeX-Ray Imaging inX-Ray

  1. Titanium and germanium lined hohlraums and halfraums as multi-keV x-ray radiators

    SciTech Connect (OSTI)

    Girard, F.; Primout, M.; Villette, B.; Stemmler, Ph.; Jacquet, L.; Babonneau, D. [CEA, DAM, DIF, F-91297 Arpajon (France); Fournier, K. B. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

    2009-05-15

    As multi-keV x-ray radiators, hohlraums and halfraums with inner walls coated with metallic materials (called liner) have been tested for the first time with laser as the energy drive. For titanium, conversion efficiencies (CEs) are up to {approx}14% for emission into 4{pi}, integrating between 4.6 and 6.5 keV when a large diameter hohlraum is used. Germanium CE is {approx}0.8% into 4{pi} between 9 and 13 keV. The highest CEs have been obtained with a 1 ns squared pulse and phase plates giving laser absorption near 99%. These high CEs are due to long-lasting, good plasma conditions for multi-keV x-ray production maintained by plasma confinement inside the plastic cylinder and plasma collision leading to a burst of x rays at a time that depends on target size. As photon emitters at 4.7 keV, titanium-lined hohlraums are the most efficient solid targets and data are close to CEs for gas targets, which are considered as the upper limit for x-ray yields since their low density allows good laser absorption and low kinetics losses. As 10.3 keV x-ray emitters, exploded germanium foils give best results one order of magnitude more efficient than thick targets; doped aerogels and lined hohlraums give similar yields, about three times lower than those from exploded foils.

  2. Spectrometer for Hard X-Ray Free Electron Laser Based on Diffraction Focusing

    E-Print Network [OSTI]

    Kohn, V G; Vartanyants, I A

    2012-01-01

    X-ray free electron lasers (XFELs) generate sequences of ultra-short, spatially coherent pulses of x-ray radiation. We propose the diffraction focusing spectrometer (DFS), which is able to measure the whole energy spectrum of the radiation of a single XFEL pulse with an energy resolution of $\\Delta E/E\\approx 2\\times 10^{-6}$. This is much better than for most modern x-ray spectrometers. Such resolution allows one to resolve the fine spectral structure of the XFEL pulse. The effect of diffraction focusing occurs in a single crystal plate due to dynamical scattering, and is similar to focusing in a Pendry lens made from the metamaterial with a negative refraction index. Such a spectrometer is easier to operate than those based on bent crystals. We show that the DFS can be used in a wide energy range from 5 keV to 20 keV.

  3. Catalog of supersoft X-ray sources

    E-Print Network [OSTI]

    J. Greiner

    2000-05-11

    This catalog comprises an up-to-date (December 1999) list of luminous (>10^36 erg/s), binary supersoft X-ray sources. This electronic version (including the accompannying Web-pages) supersedes the printed version of Greiner (1996).

  4. Multiple wavelength X-ray monochromators

    DOE Patents [OSTI]

    Steinmeyer, P.A.

    1992-11-17

    An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focusing the separate first and second output x-ray radiation wavelengths into separate focal points. 3 figs.

  5. Multiple wavelength X-ray monochromators

    DOE Patents [OSTI]

    Steinmeyer, Peter A. (Arvada, CO)

    1992-11-17

    An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focussing the separate first and second output x-ray radiation wavelengths into separate focal points.

  6. SLAC All Access: X-ray Microscope

    ScienceCinema (OSTI)

    Nelson, Johanna; Liu, Yijin

    2014-06-13

    SLAC physicists Johanna Nelson and Yijin Liu give a brief overview of the X-ray microscope at the Stanford Synchrotron Radiation Lightsource (SSRL) that is helping improve rechargeable-battery technology by letting researchers peek into the inner workings of batteries as they operate.

  7. SPECTRAL PROPERTIES OF X-RAY BINARIES IN CENTAURUS A

    SciTech Connect (OSTI)

    Burke, Mark J.; Raychaudhury, Somak [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)] [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Kraft, Ralph P.; Forman, William R.; Jones, Christine; Murray, Stephen S.; Birkinshaw, Mark; Evans, Daniel A.; Jordan, Andres [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Maccarone, Thomas J.; Croston, Judith H. [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom)] [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Brassington, Nicola J.; Hardcastle, Martin J.; Goodger, Joanna L. [School of Physics, Astronomy, and Mathematics, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom)] [School of Physics, Astronomy, and Mathematics, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Kainulainen, Jouni [Max-Planck-Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)] [Max-Planck-Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Woodley, Kristin A. [Department of Physics and Astronomy, University of British Columbia, Vancouver BC V6T 1Z1 (Canada)] [Department of Physics and Astronomy, University of British Columbia, Vancouver BC V6T 1Z1 (Canada); Sivakoff, Gregory R. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)] [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada); Gilfanov, Marat [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85741, Garching (Germany)] [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85741, Garching (Germany); Sarazin, Craig L. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States)] [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Voss, Rasmus, E-mail: mburke@star.sr.bham.ac.uk [Department of Astrophysics/IMAPP, Radboud, University Nijmegen, P.O. Box 9010, NL-6500 GL Nijmegen (Netherlands)] [Department of Astrophysics/IMAPP, Radboud, University Nijmegen, P.O. Box 9010, NL-6500 GL Nijmegen (Netherlands); and others

    2013-04-01

    We present a spectral investigation of X-ray binaries (XBs) in NGC 5128 (Cen A), using six 100 ks Chandra observations taken over two months in 2007. We divide our sample into thermally and non-thermally dominated states based on the behavior of the fitted absorption column N{sub H}, and present the spectral parameters of sources with L{sub x} {approx}> 2 Multiplication-Sign 10{sup 37} erg s{sup -1}. The majority of sources are consistent with being neutron star low-mass X-ray binaries (NS LMXBs) and we identify three transient black hole (BH) LMXB candidates coincident with the dust lane, which is the remnant of a small late-type galaxy. Our results also provide tentative support for the apparent 'gap' in the mass distribution of compact objects between {approx}2-5 M{sub Sun }. We propose that BH LMXBs are preferentially found in the dust lane, and suggest this is because of the younger stellar population. The majority ({approx}70%-80%) of potential Roche lobe filling donors in the Cen A halo are {approx}> 12 Gyr old, while BH LMXBs require donors {approx}> 1 M{sub Sun} to produce the observed peak luminosities. This requirement for more massive donors may also explain recent results that claim a steepening of the X-ray luminosity function with age at L{sub x} {>=} 5 Multiplication-Sign 10{sup 38} erg s{sup -1} for the XB population of early-type galaxies; for older stellar populations, there are fewer stars {approx}> 1 M{sub Sun }, which are required to form the more luminous sources.

  8. Rise Time Measurement for Ultrafast X-Ray Pulses

    DOE Patents [OSTI]

    Celliers, Peter M.; Weber, Franz A.; Moon, Stephen J.

    2005-04-05

    A pump-probe scheme measures the rise time of ultrafast x-ray pulses. Conventional high speed x-ray diagnostics (x-ray streak cameras, PIN diodes, diamond PCD devices) do not provide sufficient time resolution to resolve rise times of x-ray pulses on the order of 50 fs or less as they are being produced by modern fast x-ray sources. Here, we are describing a pump-probe technique that can be employed to measure events where detector resolution is insufficient to resolve the event. The scheme utilizes a diamond plate as an x-ray transducer and a p-polarized probe beam.

  9. Dispersive x-ray synchrotron studies of Pt-C multilayers

    SciTech Connect (OSTI)

    Smither, R.K.; Rodricks, B.; Lamelas, F.; Medjahed, D.; Dos Passos, W.; Clarke, R.; Ziegler, E.; Fontaine, A.

    1989-02-01

    We demonstrate the simultaneous acquisition of high-resolution x-ray absorption spectra and scattering data, using a combination of energy-dispersive optics and a two-dimensional CCD detector. Results are presented on the optical constants of Pt and on the reflectivity of a platinum-carbon multilayer at the L/sub III/ absorption edge of Pt. 12 refs., 5 figs.

  10. X-ray imaging crystal spectrometer for extended X-ray sources

    DOE Patents [OSTI]

    Bitter, Manfred L. (Princeton, NJ); Fraenkel, Ben (Jerusalem, IL); Gorman, James L. (Bordentown, NJ); Hill, Kenneth W. (Lawrenceville, NJ); Roquemore, A. Lane (Cranbury, NJ); Stodiek, Wolfgang (Princeton, NJ); von Goeler, Schweickhard E. (Princeton, NJ)

    2001-01-01

    Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokomak fusion experiment to provide spatially and temporally resolved data on plasma parameters using the imaging properties for Bragg angles near 45. For a Bragg angle of 45.degree., the spherical crystal focuses a bundle of near parallel X-rays (the cross section of which is determined by the cross section of the crystal) from the plasma to a point on a detector, with parallel rays inclined to the main plain of diffraction focused to different points on the detector. Thus, it is possible to radially image the plasma X-ray emission in different wavelengths simultaneously with a single crystal.

  11. X-RAY POINT-SOURCE POPULATIONS CONSTITUTING THE GALACTIC RIDGE X-RAY EMISSION

    SciTech Connect (OSTI)

    Morihana, Kumiko [Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)] [Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Tsujimoto, Masahiro; Ebisawa, Ken [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 3-1-1 Yoshino-dai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)] [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 3-1-1 Yoshino-dai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Yoshida, Tessei, E-mail: morihana@crab.riken.jp [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan)

    2013-03-20

    Apparently diffuse X-ray emission has been known to exist along the central quarter of the Galactic Plane since the beginning of X-ray astronomy; this is referred to as the Galactic Ridge X-ray emission (GRXE). Recent deep X-ray observations have shown that numerous X-ray point sources account for a large fraction of the GRXE in the hard band (2-8 keV). However, the nature of these sources is poorly understood. Using the deepest X-ray observations made in the Chandra bulge field, we present the result of a coherent photometric and spectroscopic analysis of individual X-ray point sources for the purpose of constraining their nature and deriving their fractional contributions to the hard-band continuum and Fe K line emission of the GRXE. Based on the X-ray color-color diagram, we divided the point sources into three groups: A (hard), B (soft and broad spectrum), and C (soft and peaked spectrum). The group A sources are further decomposed spectrally into thermal and non-thermal sources with different fractions in different flux ranges. From their X-ray properties, we speculate that the group A non-thermal sources are mostly active galactic nuclei and the thermal sources are mostly white dwarf (WD) binaries such as magnetic and non-magnetic cataclysmic variables (CVs), pre-CVs, and symbiotic stars, whereas the group B and C sources are X-ray active stars in flares and quiescence, respectively. In the log N-log S curve of the 2-8 keV band, the group A non-thermal sources are dominant above Almost-Equal-To 10{sup -14} erg cm{sup -2} s{sup -1}, which is gradually taken over by Galactic sources in the fainter flux ranges. The Fe K{alpha} emission is mostly from the group A thermal (WD binaries) and the group B (X-ray active stars) sources.

  12. ASCA Discovery of Diffuse 6.4 keV Emission Near the Sgr C Complex: A New X-ray Reflection Nebula

    E-Print Network [OSTI]

    H. Murakami; K. Koyama; M. Tsujimoto; Y. Maeda; M. Sakano

    2000-12-14

    We present an ASCA discovery of diffuse hard X-ray emission from the Sgr C complex with its peak in the vicinity of the molecular cloud core. The X-ray spectrum is characterized by a strong 6.4-keV line and large absorption. These properties suggest that Sgr C is a new X-ray reflection nebula which emits fluorescent and scattered X-rays via irradiation from an external X-ray source. We found no adequately bright source in the immediate Sgr C vicinity to fully account for the fluorescence. The irradiating source may be the Galactic nucleus Sgr A*, which was brighter in the past than it is now as is suggested from observations of the first X-ray reflection nebula Sgr B2.

  13. Suzaku X-Ray Observation of the Dwarf Nova Z Camelopardalis at the Onset of an Optical Outburst

    E-Print Network [OSTI]

    Saitou, Kei; Ebisawa, Ken; Ishida, Manabu

    2012-01-01

    We present the result of a Suzaku X-ray spectroscopic observation of the dwarf nova Z Camelopardalis, which was conducted by chance at the onset of an optical outburst. We used the X-ray Imaging Spectrometer (a 38 ks exposure) and the Hard X-ray Detector (34 ks) to obtain a 0.35-40 keV spectrum simultaneously. Spectral characteristics suggest that the source was in the X-ray quiescent state despite being in the rising phase of an outburst in the optical band. The spectrum shows a clear signature of circumstellar absorption in excess of interstellar absorption and the reprocessed emission features of Fe fluorescence and Compton scattering. The extra absorption is explained due to partial coverage by either neutral or ionized matter. We found a spectral change during the observation, which is attributable only to the change in the circumstellar absorption. Such an X-ray spectral variation is reported for the first time in dwarf novae. We speculate that the variation in the circumstellar absorption is interprete...

  14. Soft x-ray generation in gases with an ultrashort pulse laser

    SciTech Connect (OSTI)

    Ditmire, T.R.

    1996-01-08

    An experimental investigation of soft x-ray production resulting from the interaction of intense near infra-red laser radiation with gases is presented in this thesis. Specifically, soft x-ray generation through high order harmonic generation or exploiting intense inverse bremsstrahlung heating is examined. Most of these studies are conducted with femtosecond, terawatt class Cr:LiSrAlF{sub 6} (LiSAF) laser, though results derived from studies with other laser systems are presented as well. The majority of this work is devoted to experimental investigations, however, theoretical and computational models are developed to interpret the data. These studies are motivated by the possibility of utilizing the physics of intense laser/matter interactions as a potential compact source of bright x-rays. Consequently, the thrust of many of the experiments conducted is aimed at characterizing the x-rays produced for possible use in applications. In general, the studies of this manuscript fall into three categories. First, a unique 130 fs, 8 TW laser that is based on chirped pulse amplification, is described, and its performance is evaluated. The generation of x-rays through high order harmonics is then discussed with emphasis on characterizing and optimizing harmonic generation. Finally, the generation of strong, incoherent x-ray radiation by the intense irradiation of large (>1,000 atom) clusters in gas jets, is explored. The physics of laser energy absorption by clusters illuminated with intensities of 10{sup 15} to 10{sup 17} W/cm{sup 2} is considered in detail. X-ray spectroscopy of the hot plasmas that result from the irradiation of the clusters is conducted, and energy transport and kinetics issues in these plasmas are discussed.

  15. X-Ray Diffraction Microscopy of Magnetic Structures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing...

  16. ALS X-Rays Shine a New Light on Catalysis

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    times science has used high-brilliance x-rays to look so closely at these reactions. Lead author Dr. David Mueller at the ALS using x-rays to characterize working fuel cells....

  17. Using Light to Control How X Rays Interact with Matter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Using Light to Control How X Rays Interact with Matter Using Light to Control How X Rays Interact with Matter Print Wednesday, 27 January 2010 00:00 Schemes that use one light...

  18. A World's Top-10 X-ray Crystal Structure

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A World's Top-10 X-ray Crystal Structure October 7, 2014 Bookmark and Share Philip Coppens An x-ray crystal structure solved by Philip Coppens has been chosen as one of the world's...

  19. Dawn of x-ray nonlinear optics | Stanford Synchrotron Radiation...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Dawn of x-ray nonlinear optics Wednesday, July 8, 2015 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Speaker: David Reis, PULSE Program Description X-ray free electron lasers...

  20. Staff Research Physicist (X-Ray Spectroscopy) | Princeton Plasma...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    position to work on X-ray spectroscopy, atomic physics, X-ray instrumentation, and high energy density physics. Near-term research goals include participating in the design,...

  1. Trends in the Carbonyl Core (C 1S, O 1S) f *C)O Transition in the Near-Edge X-ray Absorption Fine Structure Spectra of Organic Molecules

    E-Print Network [OSTI]

    ,2 meteorites3 and interplanetary dust particles,4 eocene and recent wood,5,6 coal, coke, and other organic

  2. Accretion Disk Boundary Layers Around Neutron Stars: X-ray Production in Low-Mass X-ray Binaries

    E-Print Network [OSTI]

    Robert Popham; Rashid Sunyaev

    2000-04-03

    We present solutions for the structure of the boundary layer where the accretion disk meets the neutron star, which is expected to be the dominant source of high-energy radiation in low-mass X-ray binaries which contain weakly magnetized accreting neutron stars. We find that the main portion of the boundary layer gas is hot (> ~10^8 K), low in density, radially and vertically extended, and optically thick to scattering but optically thin to absorption. It will produce large X-ray luminosity by Comptonization. Energy is transported inward by viscosity, concentrating the energy dissipation in the dense, optically thick zone close to the stellar surface. We explore the dependence of the boundary layer structure on the mass accretion rate, the rotation rate of the star, the alpha viscosity parameter and the viscosity prescription. Radiation pressure is the dominant source of pressure in the boundary layer; the flux is close to the Eddington limiting flux even for luminosities well below (~0.01 times) L(Edd). At luminosities near L(Edd), the boundary layer expands radially, and has a radial extent larger than one stellar radius. Based on the temperatures and optical depths which characterize the boundary layer, we expect that Comptonization will produce a power-law spectrum at low source luminosities. At high luminosities, a Planckian spectrum will be produced in the dense region where most of the energy is released, and modified by Comptonization as the radiation propagates outward.

  3. H-beta Line Width and the UV-X-ray Spectra of Luminous AGN

    E-Print Network [OSTI]

    B. J. Wills; Z. Shang; J. M. Yuan

    2000-05-08

    The width of the broad H-beta emission line is the primary defining characteristic of the NLS1 class. This parameter is also an important component of Boroson and Green's optical Eigenvector 1 (EV1), which links steeper soft X-ray spectra with narrower H-beta emission, stronger H-beta blue wing, stronger optical Fe II emission, and weaker [O III] lambda 5007. Potentially, EV1 represents a fundamental physical process linking the dynamics of fueling and outflow with the accretion rate. We attempted to understand these relationships by extending the optical spectra into the UV for a sample of 22 QSOs with high quality soft-X-ray spectra, and discovered a whole new set of UV relationships that suggest that high accretion rates are linked to dense gas and perhaps nuclear starbursts. While it has been argued that narrow (BLR) H-beta means low Black Hole mass in luminous NLS1s, the C IV, lambda 1549 and Ly alpha emission lines are broader, perhaps the result of outflows driven by their high Eddington accretion rates. We present some new trends of optical-UV with X-ray spectral energy distributions. Steeper X-ray spectra appear associated with stronger UV relative to optical continua, but the presence of strong UV absorption lines is associated with depressed soft X-rays and redder optical-UV continua.

  4. High-Resolution Structure of the Photosynthetic Mn4Ca Catalyst from X-ray Spectroscopy

    SciTech Connect (OSTI)

    Yachandra, Vittal; Yano, Junko; Kern, Jan; Pushkar, Yulia; Sauer, Kenneth; Glatzel, Pieter; Bergmann, Uwe; Messinger, Johannes; Zouni, Athina; Yachandra, Vittal K.

    2007-08-01

    The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn4Ca cluster, are described. Issues of X-ray damage especially at the metal sites in the Mn4Ca cluster are discussed. The structure of the Mn4Ca catalyst at high-resolution which has so far eluded attempts of determination by X-ray diffraction, EXAFS and other spectroscopic techniques has been addressed using polarized EXAFS techniques applied to oriented PS II membrane preparations and PS II single crystals. A review of how the resolution of traditional EXAFS techniques can be improved, using methods such as range-extended EXAFS is presented, and the changes that occur in the structure of the cluster as it advances through the catalytic cycle are described. X-ray absorption and emission techniques (XANES and K? emission) have been used earlier to determine the oxidation states of the Mn4Ca cluster, and in this report we review the use of X-ray resonant Raman spectroscopy to understand the electronic structure of the Mn4Ca cluster as it cycles through the intermediate S-states.

  5. X-ray mammography with synchrotron radiation

    SciTech Connect (OSTI)

    Burattini, E. (CNR and INFN-Laboratori Nazionali di Frascati, Frascati, Rome (Italy)); Gambaccini, M.; Marziani, M.; Rimondi, O. (Dipartimento di Fisica dell'Universita and Sezione INFN di Ferrara, Ferrara (Italy)); Indovina, P.L. (Dipartimento di Scienze Fisiche dell'Universita and Sezione INFN di Napoli, Naples (Italy)); Pocek, M.; Simonetti, G. (Istituto di Radiologia, Ospedale Sant'Eugenio, Universita di Tor Vergata, Rome (Italy)); Benassi, M.; Tirelli, C. (Istituto Nazionale del Cancro, Regina Elena, Rome (Italy)); Passariello, R. (Cattedra di Radiologia, Universita dell'Aquila, L'Aquila (Italy))

    1992-01-01

    For the first time in the literature, radiographs of breast phantoms were obtained using several monochromatic synchrotron radiation x-ray beams of selected energy in the range from 14 to 26 keV. In addition, after optimization of the photon energy as a function of the phantom thickness, several mammographs were obtained on surgically removed human breast specimens containing cancer nodules. Comparison between radiographs using a conventional x-ray unit and those obtained of the same specimens utilizing synchrotron monochromatic beams clearly shows that higher contrast and better resolution can be achieved with synchrotron radiation. These results demonstrate the possibility of obtaining radiographs of excised human breast tissue containing a greater amount of radiological information using synchrotron radiation.

  6. X-ray radiography for container inspection

    DOE Patents [OSTI]

    Katz, Jonathan I. (Clayton, MO); Morris, Christopher L. (Los Alamos, NM)

    2011-06-07

    Arrangements of X-ray inspection systems are described for inspecting high-z materials in voluminous objects such as containers. Inspection methods may involve generating a radiographic image based on detected attenuation corresponding to a pulsed beams of radiation transmitted through a voluminous object. The pulsed beams of radiation are generated by a high-energy source and transmitted substantially downward along an incident angle, of approximately 1.degree. to 30.degree., to a vertical axis extending through the voluminous object. The generated radiographic image may be analyzed to detect on localized high attenuation representative of high-z materials and to discriminate high-z materials from lower and intermediate-z materials on the basis of the high density and greater attenuation of high-z material for higher energy (3-10 MeV) X-rays, and the compact nature of threatening masses of fissionable materials.

  7. High-order multilayer coated blazed gratings for high resolution soft x-ray spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Voronov, Dmitriy L.; Goray, Leonid I.; Warwick, Tony; Yashchuk, Valeriy V.; Padmore, Howard A.

    2015-02-17

    A grand challenge in soft x-ray spectroscopy is to drive the resolving power of monochromators and spectrometers from the 104 achieved routinely today to well above 105. This need is driven mainly by the requirements of a new technique that is set to have enormous impact in condensed matter physics, Resonant Inelastic X-ray Scattering (RIXS). Unlike x-ray absorption spectroscopy, RIXS is not limited by an energy resolution dictated by the core-hole lifetime in the excitation process. Using much higher resolving power than used for normal x-ray absorption spectroscopy enables access to the energy scale of soft excitations in matter. Thesemore »excitations such as magnons and phonons drive the collective phenomena seen in correlated electronic materials such as high temperature superconductors. RIXS opens a new path to study these excitations at a level of detail not formerly possible. However, as the process involves resonant excitation at an energy of around 1 keV, and the energy scale of the excitations one would like to see are at the meV level, to fully utilize the technique requires the development of monochromators and spectrometers with one to two orders of magnitude higher energy resolution than has been conventionally possible. Here we investigate the detailed diffraction characteristics of multilayer blazed gratings. These elements offer potentially revolutionary performance as the dispersive element in ultra-high resolution x-ray spectroscopy. In doing so, we have established a roadmap for the complete optimization of the grating design. Traditionally 1st order gratings are used in the soft x-ray region, but we show that as in the optical domain, one can work in very high spectral orders and thus dramatically improve resolution without significant loss in efficiency.« less

  8. FROM X-RAY DIPS TO ECLIPSE: WITNESSING DISK REFORMATION IN THE RECURRENT NOVA U Sco

    SciTech Connect (OSTI)

    Ness, J.-U.; Talavera, A.; Gonzalez-Riestra, R. [XMM-Newton Science Operations Centre, ESA, P.O. Box 78, 28691 Villanueva de la Canada, Madrid (Spain); Schaefer, B. E. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Dobrotka, A. [Department of Physics, Institute of Materials Science, Faculty of Materials Science and Technology, Slovak University of Technology, Jana Bottu 25, 91724 Trnava (Slovakia); Sadowski, A. [N. Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, 00-716 Warszawa (Poland); Drake, J. J.; Barnard, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Page, K. L. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Hernanz, M. [Institut de Ciencies de l'Espai (CSIC-IEEC), Campus UAB, Facultat de Ciencies, C5 parell 2on, 08193 Bellaterra (Barcelona) (Spain); Sala, G. [Departament Fisica i Enginyeria Nuclear, EUETIB (UPC-IEEC), Comte d'Urgell 187, 08036 Barcelona (Spain); Starrfield, S., E-mail: juness@sciops.esa.int [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States)

    2012-01-20

    The tenth recorded outburst of the recurrent eclipsing nova U Sco was observed simultaneously in X-ray, UV, and optical by XMM-Newton on days 22.9 and 34.9 after the outburst. Two full passages of the companion in front of the nova ejecta were observed, as was the reformation of the accretion disk. On day 22.9, we observed smooth eclipses in UV and optical but deep dips in the X-ray light curve that disappeared by day 34.9, yielding clean eclipses in all bands. X-ray dips can be caused by clumpy absorbing material that intersects the line of sight while moving along highly elliptical trajectories. Cold material from the companion could explain the absence of dips in UV and optical light. The disappearance of X-ray dips before day 34.9 implies significant progress in the formation of the disk. The X-ray spectra contain photospheric continuum emission plus strong emission lines, but no clear absorption lines. Both continuum and emission lines in the X-ray spectra indicate a temperature increase from day 22.9 to day 34.9. We find clear evidence in the spectra and light curves for Thompson scattering of the photospheric emission from the white dwarf. Photospheric absorption lines can be smeared out during scattering in a plasma of fast electrons. We also find spectral signatures of resonant line scattering that lead to the observation of the strong emission lines. Their dominance could be a general phenomenon in high-inclination systems such as Cal 87.

  9. X-rays from Supernova Remnants

    E-Print Network [OSTI]

    B. Aschenbach

    2002-08-28

    A summary of X-ray observations of supernova remnants is presented including the explosion fragment A of the Vela SNR, Tycho, N132D, RX J0852-4622, the Crab Nebula and the 'bulls eye', and SN 1987A, high-lighting the progress made with Chandra and XMM-Newton and touching upon the questions which arise from these observations and which might inspire future research.

  10. X-ray transient absorption and picosecond IR spectroscopy of...

    Office of Scientific and Technical Information (OSTI)

    2 ; Lawrence Livermore National Laboratory) 2 less + Show Author Affiliations (Chemical Sciences and Engineering Division) ( Publication Date: 2012-07-27 OSTI...

  11. X-ray Absorption Spectroscopy of Biologically Relevant Systems

    E-Print Network [OSTI]

    Uejio, Janel Sunayo

    2010-01-01

    sodium acetate, and lithium acetate revealing distinctpotassium, and lithium with acetate and formate anions informate and acetate solutions containing lithium, sodium,

  12. X-ray Absorption Spectroscopy: a Powerful Tool for Investigating

    E-Print Network [OSTI]

    Morante, Silvia

    Indore D 0.45 61 INDUS II Indore D 2. 3.9 Ring & Location Status E [GeV] C [Å] 7. ITALY ELETTRA Trieste D

  13. X-ray transient absorption and picosecond IR spectroscopy of

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory of rare Kaonfor DirectSciTechConnect Conference:(Journal(Journal2

  14. The X-ray Telescope of CAST

    E-Print Network [OSTI]

    M. Kuster; H. Bräuninger; S. Cébrian; M. Davenport; C. Elefteriadis; J. Englhauser; H. Fischer; J. Franz; P. Friedrich; R. Hartmann; F. H. Heinsius; D. H. H. Hoffmann; G. Hoffmeister; J. N. Joux; D. Kang; K. Königsmann; R. Kotthaus; T. Papaevangelou; C. Lasseur; A. Lippitsch; G. Lutz; J. Morales; A. Rodríguez; L. Strüder; J. Vogel; K. Zioutas

    2007-05-10

    The Cern Axion Solar Telescope (CAST) is in operation and taking data since 2003. The main objective of the CAST experiment is to search for a hypothetical pseudoscalar boson, the axion, which might be produced in the core of the sun. The basic physics process CAST is based on is the time inverted Primakoff effect, by which an axion can be converted into a detectable photon in an external electromagnetic field. The resulting X-ray photons are expected to be thermally distributed between 1 and 7 keV. The most sensitive detector system of CAST is a pn-CCD detector combined with a Wolter I type X-ray mirror system. With the X-ray telescope of CAST a background reduction of more than 2 orders off magnitude is achieved, such that for the first time the axion photon coupling constant g_agg can be probed beyond the best astrophysical constraints g_agg < 1 x 10^-10 GeV^-1.

  15. Theoretical X-ray Line Profiles from Colliding Wind Binaries

    E-Print Network [OSTI]

    Henley, D B; Pittard, J M

    2003-01-01

    We present theoretical X-ray line profiles from a range of model colliding wind systems. In particular, we investigate the effects of varying the stellar mass-loss rates, the wind speeds, and the viewing orientation. We find that a wide range of theoretical line profile shapes is possible, varying with orbital inclination and phase. At or near conjunction, the lines have approximately Gaussian profiles, with small widths (HWHM ~ 0.1 v_infty) and definite blue- or redshifts (depending on whether the star with the weaker wind is in front or behind). When the system is viewed at quadrature, the lines are generally much broader (HWHM ~ v_infty), flat-topped and unshifted. Local absorption can have a major effect on the observed profiles - in systems with mass-loss rates of a few times 10^{-6} Msol/yr the lower energy lines (E wind of the primary. The orbital variation ...

  16. Portable Parallel Beam X-Ray Diffraction System | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    than 50 pounds, and uses about 50 watts of power. The X-Beam uses polycapillary x-ray optics to collect x-rays over a large solid angle from a low-power x-ray source and to form...

  17. Small Angle X-ray Scattering (SAXS) Laboratory Learning Experiences

    E-Print Network [OSTI]

    Meagher, Mary

    .A. & Svergun D.I. (1987). Structure Analysis by Small-Angle X-Ray and Neutron Scattering. NY: Plenum PressSmall Angle X-ray Scattering (SAXS) Laboratory Learning Experiences o - Use of small angle X-ray scattering instrumentation o - Programs that you will use SAXS (BRUKER AXS) PRIMUS (Konarev, Volkov, Koch

  18. Femtosecond laser-electron x-ray source

    DOE Patents [OSTI]

    Hartemann, Frederic V.; Baldis, Hector A.; Barty, Chris P.; Gibson, David J.; Rupp, Bernhard

    2004-04-20

    A femtosecond laser-electron X-ray source. A high-brightness relativistic electron injector produces an electron beam pulse train. A system accelerates the electron beam pulse train. The femtosecond laser-electron X-ray source includes a high intra-cavity power, mode-locked laser and an x-ray optics system.

  19. Monitoring x-ray beam damage on lipid films by an integrated Brewster angle microscope/x-ray diffractometer

    E-Print Network [OSTI]

    Lee, Ka Yee C.

    Polyunsaturated lipids with conjugated tails are easily dam- aged by x-ray irradiation in the presence of oxygen samples and thin films has been detected since the beginning of x-ray studies. Dam- age to lipid samples

  20. Experimental investigation of beam heating in a soft X-ray scanning transmission X-ray microscope

    E-Print Network [OSTI]

    Hitchcock, Adam P.

    Experimental investigation of beam heating in a soft X-ray scanning transmission X-ray microscope and an accuracy of Æ1 C has been fabricated for scanning transmission X-ray microscopes (STXM). Here we describe at temperatures near their respective melting points as a means of checking for possible sample heating caused

  1. Laser wakefield generated X-ray probe for femtosecond time-resolved measurements of ionization states of warm dense aluminum

    SciTech Connect (OSTI)

    Mo, M. Z.; Chen, Z.; Tsui, Y. Y.; Fedosejevs, R. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada)] [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada); Fourmaux, S.; Saraf, A.; Otani, K.; Kieffer, J. C. [INRS-EMT, Université du Québec, 1650 Lionel Boulet, Varennes, Québec J3X 1S2 (Canada)] [INRS-EMT, Université du Québec, 1650 Lionel Boulet, Varennes, Québec J3X 1S2 (Canada); Ng, A. [Department of Physics and Astronomy, University of British Columbia, British Columbia V6T 1Z1 (Canada)] [Department of Physics and Astronomy, University of British Columbia, British Columbia V6T 1Z1 (Canada)

    2013-12-15

    We have developed a laser wakefield generated X-ray probe to directly measure the temporal evolution of the ionization states in warm dense aluminum by means of absorption spectroscopy. As a promising alternative to the free electron excited X-ray sources, Betatron X-ray radiation, with femtosecond pulse duration, provides a new technique to diagnose femtosecond to picosecond transitions in the atomic structure. The X-ray probe system consists of an adjustable Kirkpatrick-Baez (KB) microscope for focusing the Betatron emission to a small probe spot on the sample being measured, and a flat Potassium Acid Phthalate Bragg crystal spectrometer to measure the transmitted X-ray spectrum in the region of the aluminum K-edge absorption lines. An X-ray focal spot size of around 50 ?m was achieved after reflection from the platinum-coated 10-cm-long KB microscope mirrors. Shot to shot positioning stability of the Betatron radiation was measured resulting in an rms shot to shot variation in spatial pointing on the sample of 16 ?m. The entire probe setup had a spectral resolution of ?1.5 eV, a detection bandwidth of ?24 eV, and an overall photon throughput efficiency of the order of 10{sup ?5}. Approximately 10 photons were detected by the X-ray CCD per laser shot within the spectrally resolved detection band. Thus, it is expected that hundreds of shots will be required per absorption spectrum to clearly observe the K-shell absorption features expected from the ionization states of the warm dense aluminum.

  2. Comparison of SOFC Cathode Microstructure Quantified using X-ray Nanotomography and Focused Ioni Beam-scanning Electron Microscopy

    SciTech Connect (OSTI)

    G Nelson; W Harris; J Lombardo; J Izzo Jr.; W Chiu; P Tanasini; M Cantoni; J Van herle; C Comninellis; et al.

    2011-12-31

    X-ray nanotomography and focused ion beam scanning electron microscopy (FIB-SEM) have been applied to investigate the complex 3D microstructure of solid oxide fuel cell (SOFC) electrodes at spatial resolutions of 45 nm and below. The application of near edge differential absorption for x-ray nanotomography and energy selected backscatter detection for FIB-SEM enable elemental mapping within the microstructure. Using these methods, non-destructive 3D x-ray imaging and FIB-SEM serial sectioning have been applied to compare three-dimensional elemental mapping of the LSM, YSZ, and pore phases in the SOFC cathode microstructure. The microstructural characterization of an SOFC cathode is reported based on these measurements. The results presented demonstrate the viability of x-ray nanotomography as a quantitative characterization technique and provide key insights into the SOFC cathode microstructure.

  3. Comparison of SOFC Cathode Microstructure Quantified using X-ray Nanotomography and Focused Ion Beam - Scanning Electron Microscopy

    SciTech Connect (OSTI)

    Nelson, George J.; Harris, William H.; Lombardo, Jeffrey J.; Izzo, Jr., John R.; Chiu, W. K. S.; Tanasini, Pietro; Cantoni, Marco; Van herle, Jan; Comninellis, Christos; Andrews, Joy C.; Liu, Yijin; Pianetta, Piero; Chu, Yong

    2011-03-24

    X-ray nanotomography and focused ion beam scanning electron microscopy (FIB-SEM) have been applied to investigate the complex 3D microstructure of solid oxide fuel cell (SOFC) electrodes at spatial resolutions of 45 nm and below. The application of near edge differential absorption for x-ray nanotomography and energy selected backscatter detection for FIB–SEM enable elemental mapping within the microstructure. Using these methods, non-destructive 3D x-ray imaging and FIB–SEM serial sectioning have been applied to compare three-dimensional elemental mapping of the LSM, YSZ, and pore phases in the SOFC cathode microstructure. The microstructural characterization of an SOFC cathode is reported based on these measurements. The results presented demonstrate the viability of x-ray nanotomography as a quantitative characterization technique and provide key insights into the SOFC cathode microstructure.

  4. EVIDENCE OF CONTRIBUTION OF INTERVENING CLOUDS TO GAMMA-RAY BURST'S X-RAY COLUMN DENSITY

    SciTech Connect (OSTI)

    Wang, J.

    2013-10-20

    The origin of excess of X-ray column density with respect to optical extinction in gamma-ray bursts (GRBs) is still a puzzle. A proposed explanation of the excess is the photoelectric absorption due to the intervening clouds along a GRB's line of sight. Here, we test this scenario by using the intervening Mg II absorption as a tracer of the neutral hydrogen column density of the intervening clouds. We identify a connection between the large X-ray column density (and large column density ratio of log (N{sub H,X}/N{sub H{sub I}})?0.5) and large neutral hydrogen column density probed by the Mg II doublet ratio (DR). In addition, GRBs with large X-ray column density (and large ratio of log (N{sub H,X}/N{sub H{sub I}})>0) tend to have multiple saturated intervening absorbers with DR < 1.2. These results therefore indicate an additional contribution from the intervening system to the observed X-ray column density in some GRBs, although the contribution from the host galaxy alone cannot be excluded based on this study.

  5. Apparatus for monitoring X-ray beam alignment

    DOE Patents [OSTI]

    Steinmeyer, P.A.

    1991-10-08

    A self-contained, hand-held apparatus is provided for monitoring alignment of an X-ray beam in an instrument employing an X-ray source. The apparatus includes a transducer assembly containing a photoresistor for providing a range of electrical signals responsive to a range of X-ray beam intensities from the X-ray beam being aligned. A circuit, powered by a 7.5 VDC power supply and containing an audio frequency pulse generator whose frequency varies with the resistance of the photoresistor, is provided for generating a range of audible sounds. A portion of the audible range corresponds to low X-ray beam intensity. Another portion of the audible range corresponds to high X-ray beam intensity. The transducer assembly may include an a photoresistor, a thin layer of X-ray fluorescent material, and a filter layer transparent to X-rays but opaque to visible light. X-rays from the beam undergoing alignment penetrate the filter layer and excite the layer of fluorescent material. The light emitted from the fluorescent material alters the resistance of the photoresistor which is in the electrical circuit including the audio pulse generator and a speaker. In employing the apparatus, the X-ray beam is aligned to a complete alignment by adjusting the X-ray beam to produce an audible sound of the maximum frequency. 2 figures.

  6. HgMn Stars as apparent X-ray emitters

    E-Print Network [OSTI]

    Hubrig, S; Mathys, G

    1998-01-01

    In the ROSAT all-sky survey 11 HgMn stars were detected as soft X-ray emitters (Berghoefer, Schmitt & Cassinelli 1996). Prior to ROSAT, X-ray observations with the Einstein Observatory had suggested that stars in the spectral range B5-A7 are devoid of X-ray emission. Since there is no X-ray emitting mechanism available for these stars (also not for HgMn stars), the usual argument in the case of an X-ray detected star of this spectral type is the existence of an unseen low-mass companion which is responsible for the X-ray emission. The purpose of the present work is to use all available data for our sample of X-ray detected HgMn stars and conclude on the nature of possible companions.

  7. X-Ray Imaging Crystal Spectrometer for Extended X-Ray Sources

    SciTech Connect (OSTI)

    Bitter, Manfred L.; Fraekel, Benjamin; Gorman, James L.; Hill, Kenneth W.; Roquemore, Lane A.; Stodiek, Wolfgang; Goeler, Schweickhard von

    1999-05-01

    Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokamak fusion experiment to provide spatially and temporally resolved data on plasma parameters such as ion temperature, toroidal and poloidal rotation, electron temperature, impurity ion charge-state distributions, and impurity transport. The imaging properties of these spherically or toroidally curved crystals provide both spectrally and spatially resolved X-ray data from the plasma using only one small spherically or toroidally curved crystal, thus eliminating the requirement for a large array of crystal spectrometers and the need to cross-calibrate the various crystals.

  8. X-ray emission properties of galaxies in Abell 3128

    E-Print Network [OSTI]

    Russell J. Smith

    2003-07-15

    We use archival Chandra X-ray Observatory data to investigate X-ray emission from early-type galaxies in the rich z=0.06 cluster Abell 3128. By combining the X-ray count-rates from an input list of optically-selected galaxies, we obtain a statistical detection of X-ray flux, unbiased by X-ray selection limits. Using 87 galaxies with reliable Chandra data, X-ray emission is detected for galaxies down to M_B ~ -19.0, with only an upper limit determined for galaxies at M_B ~ -18.3. The ratio of X-ray to optical luminosities is consistent with recent determinations of the low-mass X-ray binary content of nearby elliptical galaxies. Taken individually, in contrast, we detect significant (3sigma) flux for only six galaxies. Of these, one is a foreground galaxy, while two are optically-faint galaxies with X-ray hardness ratios characteristic of active galactic nuclei. The remaining three detected galaxies are amongst the optically-brightest cluster members, and have softer X-ray spectra. Their X-ray flux is higher than that expected from X-ray binaries, by a factor 2-10; the excess suggests these galaxies have retained their hot gaseous haloes. The source with the highest L_X / L_B ratio is of unusual optical morphology with prominent sharp-edged shells. Notwithstanding these few exceptions, the cluster population overall exhibits X-ray properties consistent with their emission being dominated by X-ray binaries. We conclude that in rich cluster environments, interaction with the ambient intra-cluster medium acts to strip most galaxies of their hot halo gas.

  9. Metrology for the advancement of x-ray optics at the ALS

    E-Print Network [OSTI]

    Goldberg, Kenneth

    2014-01-01

    S. Yuan et al. , X-ray Optics and Instrumentation 2010,in X-ray and Neutron Optics, Springer, Berlin S. G. AlcockX-ray beam metrology and X-ray optic alignment by Hartmann

  10. X-ray Selected Clusters of Galaxies

    E-Print Network [OSTI]

    Isabella M. Gioia

    1996-01-21

    This paper given at the meeting on "Mapping, Measuring and Modelling the Universe" presents three topics: 1) the study of the clusters and groups of galaxies found serendipitously in the North Ecliptic Pole (NEP) region of the ROSAT all-sky survey; 2) the highest redshift clusters found in the EMSS (up to z=0.82) and the cosmological implications of their very existence; 3) the gravitational lensing in the EMSS X-ray selected clusters of galaxies observed by the Hubble Space Telescope.

  11. SMB, Small Angle X-Ray Scattering

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust, High-Throughput Analysis of Protein1-0845*RV 14800Small Angle X-Ray Scattering Home »

  12. SMB, X-ray Emission Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust, High-Throughput Analysis of Protein1-0845*RV 14800Small Angle X-Ray Scattering

  13. SMB, X-ray Fluorescence Imaging

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust, High-Throughput Analysis of Protein1-0845*RV 14800Small Angle X-Ray

  14. X-Ray Microscopy | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWindX-Ray ImagingIn the

  15. X-ray Microscopy and Imaging: FAQs

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWindX-Ray

  16. Lensless X-Ray Imaging in Reflection

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse Bergkamp GraduateResidentialLensless Imaging of WholeX-Ray Imaging in

  17. Lensless X-Ray Imaging in Reflection

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse Bergkamp GraduateResidentialLensless Imaging of WholeX-Ray Imaging

  18. Lensless X-Ray Imaging in Reflection

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and-E C H N I CLensless X-Ray Imaging in

  19. Lensless X-Ray Imaging in Reflection

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and-E C H N I CLensless X-Ray Imaging

  20. Lensless X-Ray Imaging in Reflection

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and-E C H N I CLensless X-Ray ImagingLensless

  1. Lensless X-Ray Imaging in Reflection

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and-E C H N I CLensless X-Ray

  2. On Relativistic Disk Spectroscopy in Compact Objects with X-ray CCD Cameras

    E-Print Network [OSTI]

    J. M. Miller; A. D'Ai; M. W. Bautz; S. Bhattacharyya; D. N. Burrows; E. M. Cackett; A. C. Fabian; M. J. Freyberg; F. Haberl; J. Kennea; M. A Nowak; R. C. Reis; T. E. Strohmayer; M. Tsujimoto

    2010-09-22

    X-ray charge-coupled devices (CCDs) are the workhorse detectors of modern X-ray astronomy. Typically covering the 0.3-10.0 keV energy range, CCDs are able to detect photoelectric absorption edges and K shell lines from most abundant metals. New CCDs also offer resolutions of 30-50 (E/dE), which is sufficient to detect lines in hot plasmas and to resolve many lines shaped by dynamical processes in accretion flows. The spectral capabilities of X-ray CCDs have been particularly important in detecting relativistic emission lines from the inner disks around accreting neutron stars and black holes. One drawback of X-ray CCDs is that spectra can be distorted by photon "pile-up", wherein two or more photons may be registered as a single event during one frame time. We have conducted a large number of simulations using a statistical model of photon pile-up to assess its impacts on relativistic disk line and continuum spectra from stellar-mass black holes and neutron stars. The simulations cover the range of current X-ray CCD spectrometers and operational modes typically used to observe neutron stars and black holes in X-ray binaries. Our results suggest that severe photon pile-up acts to falsely narrow emission lines, leading to falsely large disk radii and falsely low spin values. In contrast, our simulations suggest that disk continua affected by severe pile-up are measured to have falsely low flux values, leading to falsely small radii and falsely high spin values. The results of these simulations and existing data appear to suggest that relativistic disk spectroscopy is generally robust against pile-up when this effect is modest.

  3. ON RELATIVISTIC DISK SPECTROSCOPY IN COMPACT OBJECTS WITH X-RAY CCD CAMERAS

    SciTech Connect (OSTI)

    Miller, J. M.; Cackett, E. M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); D'Ai, A. [Dipartimento di Scienze Fisiche ed Astronomiche, Universita di Palermo, Palermo (Italy); Bautz, M. W.; Nowak, M. A. [Kavli Institute for Astrophysics and Space Research, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Bhattacharyya, S. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Burrows, D. N.; Kennea, J. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, College Park, PA 16802 (United States); Fabian, A. C.; Reis, R. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 OHA (United Kingdom); Freyberg, M. J.; Haberl, F. [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Strohmayer, T. E. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Tsujimoto, M., E-mail: jonmm@umich.ed [Japan Aerospace Exploration Agency, Institute of Space and Astronomical Sciences, 3-1-1 Yoshino-dai, Sagamihara, Kanagawa 229-8510 (Japan)

    2010-12-01

    X-ray charge-coupled devices (CCDs) are the workhorse detectors of modern X-ray astronomy. Typically covering the 0.3-10.0 keV energy range, CCDs are able to detect photoelectric absorption edges and K shell lines from most abundant metals. New CCDs also offer resolutions of 30-50 (E/{Delta}E), which is sufficient to detect lines in hot plasmas and to resolve many lines shaped by dynamical processes in accretion flows. The spectral capabilities of X-ray CCDs have been particularly important in detecting relativistic emission lines from the inner disks around accreting neutron stars and black holes. One drawback of X-ray CCDs is that spectra can be distorted by photon 'pile-up', wherein two or more photons may be registered as a single event during one frame time. We have conducted a large number of simulations using a statistical model of photon pile-up to assess its impacts on relativistic disk line and continuum spectra from stellar-mass black holes and neutron stars. The simulations cover the range of current X-ray CCD spectrometers and operational modes typically used to observe neutron stars and black holes in X-ray binaries. Our results suggest that severe photon pile-up acts to falsely narrow emission lines, leading to falsely large disk radii and falsely low spin values. In contrast, our simulations suggest that disk continua affected by severe pile-up are measured to have falsely low flux values, leading to falsely small radii and falsely high spin values. The results of these simulations and existing data appear to suggest that relativistic disk spectroscopy is generally robust against pile-up when this effect is modest.

  4. Constraining Black Hole Spin Via X-ray Spectroscopy

    E-Print Network [OSTI]

    Laura W. Brenneman; Christopher S. Reynolds

    2006-08-23

    We present an analysis of the observed broad iron line feature and putative warm absorber in the long 2001 XMM-Newton observation of the Seyfert-1.2 galaxy MCG-6-30-15. The new "kerrdisk" model we have designed for simulating line emission from accretion disk systems allows black hole spin to be a free parameter in the fit, enabling the user to formally constrain the angular momentum of a black hole, among other physical parameters of the system. In an important extension of previous work, we derive constraints on the black hole spin in MCG-6-30-15 using a self-consistent model for X-ray reflection from the surface of the accretion disk while simultaneously accounting for absorption by dusty photoionized material along the line of sight (the warm absorber). Even including these complications, the XMM-Newton/EPIC-pn data require extreme relativistic broadening of the X-ray reflection spectrum; assuming no emission from within the radius of marginal stability, we derive a formal constraint on the dimensionless black hole spin parameter of a > 0.987 at 90% confidence. The principal unmodeled effect that can significantly reduce the inferred black hole spin is powerful emission from within the radius of marginal stability. Although significant theoretical developments are required to fully understand this region, we argue that the need for a rapidly spinning black hole is robust to physically plausible levels of emission from within the radius of marginal stability. In particular, we show that a non-rotating black hole is strongly ruled out.

  5. Discovery of a z=4.93, X-ray selected quasar by the Chandra Multiwavelength Project (ChamP)

    E-Print Network [OSTI]

    Silverman, J D; Kim, D W; Wilkes, B J; Cameron, R A; Morris, D; Dosaj, A; Smith, C; Infante, L; Smith, P S; Jannuzi, B T

    2002-01-01

    We present X-ray and optical observations of CXOMP J213945.0-234657, a high redshift (z=4.93) quasar discovered through the Chandra Multiwavelength Project (ChaMP). This object is the most distant X-ray selected quasar published, with an X-ray luminosity of L(X)=5.9x10^44 erg/s (measured in the 0.3-2.5 keV band and corrected for Galactic absorption). CXOMP J213945.0-234657 is a g' dropout object (>26.2), with r'=22.87 and i'=21.36. The rest-frame X-ray to optical flux ratio is similar to quasars at lower redshifts and slightly X-ray bright relative to z>4 optically-selected quasars observed with Chandra. The ChaMP is beginning to acquire significant numbers of high redshift quasars to investigate the unobscured X-ray luminosity function out to z~5.

  6. Soft x-ray reduction camera for submicron lithography

    DOE Patents [OSTI]

    Hawryluk, Andrew M. (2708 Rembrandt Pl., Modesto, CA 95356); Seppala, Lynn G. (7911 Mines Rd., Livermore, CA 94550)

    1991-01-01

    Soft x-ray projection lithography can be performed using x-ray optical components and spherical imaging lenses (mirrors), which form an x-ray reduction camera. The x-ray reduction is capable of projecting a 5x demagnified image of a mask onto a resist coated wafer using 4.5 nm radiation. The diffraction limited resolution of this design is about 135 nm with a depth of field of about 2.8 microns and a field of view of 0.2 cm.sup.2. X-ray reflecting masks (patterned x-ray multilayer mirrors) which are fabricated on thick substrates and can be made relatively distortion free are used, with a laser produced plasma for the source. Higher resolution and/or larger areas are possible by varying the optic figures of the components and source characteristics.

  7. Fabrication process for a gradient index x-ray lens

    DOE Patents [OSTI]

    Bionta, Richard M. (Livermore, CA); Makowiecki, Daniel M. (Livermore, CA); Skulina, Kenneth M. (Livermore, CA)

    1995-01-01

    A process for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments m the soft x-ray region.

  8. Fabrication process for a gradient index x-ray lens

    DOE Patents [OSTI]

    Bionta, R.M.; Makowiecki, D.M.; Skulina, K.M.

    1995-01-17

    A process is disclosed for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments in the soft x-ray region. 13 figures.

  9. Density gradient free electron collisionally excited x-ray laser

    DOE Patents [OSTI]

    Campbell, E.M.; Rosen, M.D.

    1984-11-29

    An operational x-ray laser is provided that amplifies 3p-3s transition x-ray radiation along an approximately linear path. The x-ray laser is driven by a high power optical laser. The driving line focused optical laser beam illuminates a free-standing thin foil that may be associated with a substrate for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the x-ray laser gain medium. The x-ray laser may be driven by more than one optical laser beam. The x-ray laser has been successfully demonstrated to function in a series of experimental tests.

  10. Density gradient free electron collisionally excited X-ray laser

    DOE Patents [OSTI]

    Campbell, Edward M. (Pleasanton, CA); Rosen, Mordecai D. (Berkeley, CA)

    1989-01-01

    An operational X-ray laser (30) is provided that amplifies 3p-3s transition X-ray radiation along an approximately linear path. The X-ray laser (30) is driven by a high power optical laser. The driving line focused optical laser beam (32) illuminates a free-standing thin foil (34) that may be associated with a substrate (36) for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the X-ray laser gain medium. The X-ray laser (30) may be driven by more than one optical laser beam (32, 44). The X-ray laser (30) has been successfully demonstrated to function in a series of experimental tests.

  11. X-ray Emission from Ionized Wind-Bubbles around Wolf-Rayet Stars

    E-Print Network [OSTI]

    Dwarkadas, Vikram V

    2015-01-01

    Using a code that employs a self-consistent method for computing the effects of photoionization on circumstellar gas dynamics, we model the formation of wind-driven nebulae around massive Wolf-Rayet (W-R) stars. Our algorithm incorporates a simplified model of the photo-ionization source, computes the fractional ionization of hydrogen due to the photoionizing flux and recombination, and determines self-consistently the energy balance due to ionization, photo-heating and radiative cooling. We take into account changes in stellar properties and mass-loss over the star's evolution. Our multi-dimensional simulations clearly reveal the presence of strong ionization front instabilities. Using various X-ray emission models, and abundances consistent with those derived for W-R nebulae, we compute the X-ray flux and spectra from our wind bubble models. We show the evolution of the X-ray spectral features with time over the evolution of the star, taking the absorption of the X-rays by the ionized bubble into account. O...

  12. Protein crystallography: From X-ray diffraction spots to a three dimensional image

    SciTech Connect (OSTI)

    Terwilliger, T.C.; Berendzen, J.

    1998-02-25

    Proteins are remarkable molecular machines that are essential for life. They can do many things ranging from the precise control of blood clotting to synthesizing complex organic compounds. Pictures of protein molecules are in high demand in biotechnology because they are important for applications such as drug discovery and for engineering enzymes for commercial use. X-ray crystallography is the most common method for determining the three-dimensional structures of protein molecules. When a crystal of a protein is placed in an X-ray beam, scattering of X-rays off the ordered molecules produces a diffraction pattern that can be measured on a position-sensitive CCD or image-plate detector. Protein crystals typically contain thousands of atoms and the diffraction data are generally measured to relatively low resolution. Consequently the direct methods approaches generally cannot be applied. Instead, if the crystal is modified by adding metal atoms at specific sites or by tuning the wavelength of the X-rays to cross an absorption edge of a metal atom in the crystal, then the information from these additional measurements is sufficient to first identify the /locations of the metal atoms. This information is then used along with the diffraction data to make a three-dimensional picture of electron densities. This picture can be used to determine the position of most or all of the atoms in the protein.

  13. SIMULTANEOUS X-RAY AND RADIO OBSERVATIONS OF ROTATING RADIO TRANSIENT J1819-1458

    SciTech Connect (OSTI)

    Miller, J. J.; McLaughlin, M. A. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Rea, N. [Institut de Ciències de l'Espai (IEEC-CSIC) Campus UAB, Fac. de Ciències, Torre C5, parell, 2a planta, E-08193 Barcelona (Spain); Lazaridis, K.; Keane, E. F.; Kramer, M. [Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Lyne, A. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

    2013-10-20

    We present the results of simultaneous radio and X-ray observations of PSR J1819–1458. Our 94 ks XMM-Newton observation of the high magnetic field (?5 × 10{sup 13} G) pulsar reveals a blackbody spectrum (kT ? 130 eV) with a broad absorption feature, possibly composed of two lines at ?1.0 and ?1.3 keV. We performed a correlation analysis of the X-ray photons with radio pulses detected in 16.2 hr of simultaneous observations at 1-2 GHz with the Green Bank, Effelsberg, and Parkes telescopes, respectively. Both the detected X-ray photons and radio pulses appear to be randomly distributed in time. We find tentative evidence for a correlation between the detected radio pulses and X-ray photons on timescales of less than 10 pulsar spin periods, with the probability of this occurring by chance being 0.46%. This suggests that the physical process producing the radio pulses may also heat the polar-cap.

  14. Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Deng, Junjing; Vine, David J.; Chen, Si; Nashed, Youssef S. G.; Jin, Qiaoling; Phillips, Nicholas W.; Peterka, Tom; Ross, Rob; Vogt, Stefan; Jacobsen, Chris J.

    2015-02-24

    Trace metals play important roles in normal and in disease-causing biological functions. X-ray fluorescence microscopy reveals trace elements with no dependence on binding affinities (unlike with visible light fluorophores) and with improved sensitivity relative to electron probes. However, X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular material. Here we show that X-ray ptychography can be combined with fluorescence to image both cellular structure and trace element distribution in frozen-hydrated cells at cryogenic temperatures, with high structural and chemical fidelity. Ptychographic reconstruction algorithms deliver phase and absorption contrast images at a resolutionmore »beyond that of the illuminating lens or beam size. Using 5.2-keV X-rays, we have obtained sub–30-nm resolution structural images and ~90-nm–resolution fluorescence images of several elements in frozen-hydrated green algae. This combined approach offers a way to study the role of trace elements in their structural context.« less

  15. On Relativistic Disk Spectroscopy in Compact Objects with X-ray CCD Cameras

    E-Print Network [OSTI]

    Miller, J M; Bautz, M W; Bhattacharyya, S; Burrows, D N; Cackett, E M; Fabian, A C; Freyberg, M J; Haberl, F; Kennea, J; Nowak, M A; Reis, R C; Strohmayer, T E; Tsujimoto, M

    2010-01-01

    X-ray charge-coupled devices (CCDs) are the workhorse detectors of modern X-ray astronomy. Typically covering the 0.3-10.0 keV energy range, CCDs are able to detect photoelectric absorption edges and K shell lines from most abundant metals. New CCDs also offer resolutions of 30-50 (E/dE), which is sufficient to detect lines in hot plasmas and to resolve many lines shaped by dynamical processes in accretion flows. The spectral capabilities of X-ray CCDs have been particularly important in detecting relativistic emission lines from the inner disks around accreting neutron stars and black holes. One drawback of X-ray CCDs is that spectra can be distorted by photon "pile-up", wherein two or more photons may be registered as a single event during one frame time. We have conducted a large number of simulations using a statistical model of photon pile-up to assess its impacts on relativistic disk line and continuum spectra from stellar-mass black holes and neutron stars. The simulations cover the range of current X-...

  16. X-Ray Observations of the Sagittarius D HII Region toward the Galactic Center with Suzaku

    E-Print Network [OSTI]

    Makoto Sawada; Masahiro Tsujimoto; Katsuji Koyama; Casey J. Law; Takeshi Go Tsuru; Yoshiaki Hyodo

    2008-05-14

    We present a Suzaku X-ray study of the Sagittarius D (Sgr D) HII region in the Galactic center region. Two 18'x18' images by the X-ray Imaging Spectrometer (XIS) encompass the entire Sgr D complex. Thanks to the low background, XIS discovered two diffuse sources with low surface brightness and obtained their high signal-to-noise ratio spectra. One is associated with the core of the Sgr D HII region, arising from the young stellar cluster. The other is a new object in the vicinity of the region. We also present 3.5 cm and 6.0 cm radio continuum maps of the new source using the 100 m Green Bank Telescope. We conclude that the source is a new supernova remnant (SNR; G1.2--0.0) based on: (1) the 0.9+/-0.2 keV thermal X-ray spectrum with emission lines from highly ionized atoms; (2) the diffuse nature with an apparent extent of ~10 pc at the Galactic center distance inferred from the X-ray absorption (~8.5x10^{22} cm^{-2}); and (3) the nonthermal radio continuum spectral index (~-0.5). Our discovery of an SNR in the Sgr D HII region leads to a revision of the view of this system, which had been considered to be a thermal HII region and its environment.

  17. ISOCAM Photometry of Narrow-Line X-ray Galaxies

    E-Print Network [OSTI]

    J. D. Law-Green; A. Zezas; M. J. Ward; C. Boisson

    1998-12-23

    Mid-infrared photometry of the hosts of Narrow-Line X-ray Galaxies at 6 microns and 12 microns has been attempted with ISOCAM. No conclusive detections have been made. This implies that these are quiescent objects with little or no active star-formation. Neither X-ray binaries nor starburst-driven superwinds are consistent explanations for the X-ray emission in these objects. We conclude that these NLXGs are predominantly AGN-powered.

  18. X-ray transmission movies of spontaneous dynamic events

    SciTech Connect (OSTI)

    Smilowitz, L.; Henson, B. F.; Holmes, M.; Novak, A.; Oschwald, D.; Dolgonos, P.; Qualls, B.

    2014-11-15

    We describe a new x-ray radiographic imaging system which allows for continuous x-ray transmission imaging of spontaneous dynamic events. We demonstrate this method on thermal explosions in three plastic bonded formulations of the energetic material octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine. We describe the x-ray imaging system and triggering developed to enable the continuous imaging of a thermal explosion.

  19. X-ray interferometry with spherically bent crystals (abstract)

    SciTech Connect (OSTI)

    Koch, Jeffrey A.

    2001-01-01

    Recent progress in manufacturing high-quality spherically bent crystals allows highly monochromatic x-ray beams to be produced, and allows efficient x-ray imaging with {mu}m-scale resolution. This article explores some of the constraints for x-ray interferometry utilizing spherically bent crystals and laser-produced plasma sources, and discusses several shearing interferometer concepts that might be experimentally investigated.

  20. Legacy of the X-Ray Laser Program

    SciTech Connect (OSTI)

    Nilsen, J.

    1993-08-06

    The X-Ray Laser Program has evolved from a design effort focusing on developing a Strategic Defense Initiative weapon that protects against Soviet ICBMs to a scientific project that is producing new technologies for industrial and medical research. While the great technical successes and failures of the X-ray laser itself cannot be discussed, this article presents the many significant achievements made as part of the X-ray laser effort that are now being used for other applications at LLNL.

  1. Ultra-short wavelength x-ray system

    DOE Patents [OSTI]

    Umstadter, Donald (Ann Arbor, MI); He, Fei (Ann Arbor, MI); Lau, Yue-Ying (Potomac, MD)

    2008-01-22

    A method and apparatus to generate a beam of coherent light including x-rays or XUV by colliding a high-intensity laser pulse with an electron beam that is accelerated by a synchronized laser pulse. Applications include x-ray and EUV lithography, protein structural analysis, plasma diagnostics, x-ray diffraction, crack analysis, non-destructive testing, surface science and ultrafast science.

  2. X-ray micromodulated luminescence tomography in dual-cone ...

    E-Print Network [OSTI]

    2014-07-01

    Jul 16, 2014 ... source, a polycapillary lens, and an electron multiplying charge coupled device ... sources generate x-rays by accelerating electrons into high-z.

  3. X-Ray Characterization of Diesel Sprays | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Sprays X-Ray Characterization of Diesel Sprays 2005 Diesel Engine Emissions Reduction (DEER) Conference Presentations and Posters 2005deerpowell.pdf More Documents & Publications...

  4. Probing Spatial, Electronic Structures with X-ray Scattering...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Probing Spatial, Electronic Structures with X-ray Scattering, Spectroscopic Techniques Wednesday, September 5, 2012 - 10:45am SLAC, Bldg. 137, Room 226 Gang Chen Seminar:...

  5. X-Ray Diffraction Microscopy of Magnetic Structures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of...

  6. In situ X-ray Characterization of Energy Storage Materials |...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Scholar, SSRL MSD Hard X-ray Department A key factor in the global move towards clean, renewable energy is the electrification of the automobile. Current battery technology...

  7. Dissociation of strong acid revisited: X-ray photoelectron spectroscop...

    Office of Scientific and Technical Information (OSTI)

    X-ray photoelectron spectroscopy and molecular dynamics simulations of HNO3 in water Citation Details In-Document Search Title: Dissociation of strong acid revisited:...

  8. Simulating Wavefront Correction via Deformable Mirrors at X-Ray...

    Office of Scientific and Technical Information (OSTI)

    Resource Type: Conference Resource Relation: Conference: Presented at: X-ray Adaptive Optics, San Diego, CA, United States, Aug 14 - Aug 14, 2012 Research Org: Lawrence Livermore...

  9. A Record Run for the APS X-ray Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    signals that comprise radiation interlock systems protecting personnel and equipment; * Beam diagnostics controlling multiple x-ray beams simultaneously while utilizing more than...

  10. Insight into obscure transition uncovered by X-rays | Argonne...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of X-ray techniques. This transition has ramifications for material design for electronics and sensors. The transition between being electrically conductive (metallic) at...

  11. Advances in X-Ray Diagnostics of Diesel Fuel Sprays

    Broader source: Energy.gov [DOE]

    Recent advances in high-speed X-ray imaging has shown several distinct behaviors of commercial fuel injectors that cannot be seen with more conventional techniques.

  12. X-ray image reconstruction from a diffraction pattern alone

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Marchesini, Stefano

    X-ray diffraction pattern of a sample of 50 nm colloidal gold particles, recorded at a wavelength of 2.1 nm.

  13. X-ray Emission from Isolated Be Stars

    E-Print Network [OSTI]

    David H. Cohen

    2000-08-22

    I discuss the X-ray observations of Be stars, and how their properties compare to non-emission B stars. I focus on several specific stars that show high flux levels and variability but also report on several interesting survey results. The Be X-ray properties are discussed in the context of wind-shock X-ray emission from normal OB stars as well as in the context of general mechanisms that have been proposed to explain the Be phenomenon. Finally, I conclude with a discussion of the spectral diagnostics that will be available from the new generation of X-ray telescopes.

  14. Characterization of spatially resolved high resolution x-ray...

    Office of Scientific and Technical Information (OSTI)

    Characterization of spatially resolved high resolution x-ray spectrometers for high energy density physics and light source experiments Citation Details In-Document Search Title:...

  15. X-ray microscopy at CNM | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWindX-RayX-Ray ScienceX-RayX-ray

  16. FIRST IMAGES FROM THE FOCUSING OPTICS X-RAY SOLAR IMAGER

    SciTech Connect (OSTI)

    Krucker, Säm; Glesener, Lindsay; Turin, Paul; McBride, Stephen; Glaser, David; Fermin, Jose; Lin, Robert; Christe, Steven; Ishikawa, Shin-nosuke; Ramsey, Brian; Gubarev, Mikhail; Kilaru, Kiranmayee; Takahashi, Tadayuki; Watanabe, Shin; Saito, Shinya; Tanaka, Takaaki; White, Stephen

    2014-10-01

    The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket payload flew for the first time on 2012 November 2, producing the first focused images of the Sun above 5 keV. To enable hard X-ray (HXR) imaging spectroscopy via direct focusing, FOXSI makes use of grazing-incidence replicated optics combined with fine-pitch solid-state detectors. On its first flight, FOXSI observed several targets that included active regions, the quiet Sun, and a GOES-class B2.7 microflare. This Letter provides an introduction to the FOXSI instrument and presents its first solar image. These data demonstrate the superiority in sensitivity and dynamic range that is achievable with a direct HXR imager with respect to previous, indirect imaging methods, and illustrate the technological readiness for a spaceborne mission to observe HXRs from solar flares via direct focusing optics.

  17. ASCA PV observations of the Seyfert 2 galaxy NGC 4388 the obscured nucleus and its X-ray emission

    E-Print Network [OSTI]

    Iwasawa, K; Ueno, S; Awaki, H; Fukazawa, Y; Matsushita, K; Makishima, K

    1996-01-01

    We present results on the Seyfert 2 galaxy NGC4388 in the Virgo cluster observed with ASCA during its PV phase. The 0.5-10 keV X-ray spectrum consists of multiple components; (1) a continuum component heavily absorbed by a column density NH = 4E23 cm-2 above 3 keV; (2) a strong 6.4 keV line (EW = 500 eV); (3) a weak flat continuum between 1 and 3 keV; and (4) excess soft X-ray emission below 1 keV. The detection of strong absorption for the hard X-ray component is firm evidence for an obscured active nucleus in this Seyfert 2 galaxy. The absorption corrected X-ray luminosity is about 2E42 erg/s. This is the first time that the fluorescent iron-K line has been detected in this object. The flat spectrum in the intermediate energy range may be a scattered continuum from the central source. The soft X-ray emission below 1 keV can be thermal emission from a temperature kT = 0.5 keV, consistent with the spatially extended emission observed by ROSAT HRI. However, the low abundance (0.05 Zs) and high mass flow rate r...

  18. Influence of the water content on X-ray fluorescence core-scanning measurements in soft marine sediments

    E-Print Network [OSTI]

    Tjallingii, Rik

    Influence of the water content on X-ray fluorescence core- scanning measurements in soft marine properties such as density and water content on XRF core scanner data. Comparison of XRF scanner measurements for the radiation absorption of the water content in sediment core GeoB7920 off Cape Blanc, NW Africa. Components

  19. Quantitative Analysis of Resolved X-ray Emission Line Profiles of O Stars: Profile Symmetry: Clumping and

    E-Print Network [OSTI]

    Cohen, David

    snapshot from a 1-D rad-hydro simulation of an O star wind. Note the discontinuities in velocity. These are shock fronts, compressing and heating the wind, producing x-rays. There are dense inter-shock regions, containing most of the wind mass, in which cold material provides a source of photoelectric absorption #12

  20. Study of LINER sources with broad H(alpha) emission. X-ray properties and comparision to luminous AGN and X-ray binaries

    E-Print Network [OSTI]

    George, Younes; Sabra, B; Reeves, J N

    2011-01-01

    [Abridged]We study the X-ray properties of LINER sources with definite detection of a broad H(alpha) emission line in their optical spectra, LINER 1s from Ho et al. sample. These objects preferentially harbor a low luminosity active nucleus at the center and show small or no intrinsic absorption (<10^(22) cm^(-1)). We analyzed all available X-ray archived XMM-Newton and Chandra observations of 13 LINER 1s satisfying the above criterion in a systematic homogeneous way. We looked for any correlations between the X-ray properties and the intrinsic parameters of our sample of LINER 1s. An absorbed power-law gave a good fit to the spectra of 9 out of the 13 sources. A thermal component and an absorbed power-law were required in the remaining 4 sources. We found a photon index between 1.3\\pm0.2 for the hardest source and 2.4^(+0.2)_(-0.3) for the softest one with a mean value of 1.9\\pm0.2 and a dispersion sigma=0.3. The thermal component had a mean temperature kT~0.6 keV. Significant short (hours to days) time-s...

  1. Green's functions for transmission of X-rays and gamma-rays through cold media

    E-Print Network [OSTI]

    P. Magdziarz; A. A. Zdziarski

    1996-07-03

    Using a Monte Carlo method, we study Compton scattering and absorption of X-rays and gamma-rays in cold media. We consider transmission of X/gamma-rays through a shell of an arbitrary optical depth, for which we derive energy-dependent Green's functions. Fitting the Green functions with simple analytical formulae is in progress. We also present a simple treatment of the effect of absorption on Green's functions for Compton scattering, which allow to treat media with an arbitrary ionization state and chemical composition. Our transmission Green's functions allow to treat Thomson-thick absorbers, e.g. molecular tori of Seyfert 2s.

  2. Refraction-Enhanced X-ray Radiography for Inertial Confinement Fusion and Laser-Produced Plasma Applications

    SciTech Connect (OSTI)

    Koch, J A; Landen, O L; Kozioziemski, B J; Izumi, N; Dewald, E L; Salmonson, J D; Hammel, B A

    2008-08-26

    We explore various laser-produced plasma and inertial-confinement fusion (ICF) applications of phase-contrast x-ray radiography, and we show how the main features of these enhancements can be considered from a geometrical optics perspective as refraction enhancements. This perspective simplifies the analysis, and often permits simple analytical formulae to be derived that predict the enhancements. We explore a raytrace approach to various material interface applications, and we explore a more general example of refractive bending of x-rays by an implosion plasma. We find that refraction-enhanced x-ray radiography of implosions may provide a means to quantify density differences across shock fronts as well as density variations caused by local heating due to high-Z dopants. We also point out that refractive bending by implosions plasmas can blur fine radiograph features, and can also provide misleading contrast information in area-backlit pinhole imaging experiments unless its effects are taken into consideration.

  3. Automated Chemical Analysis of Internally Mixed Aerosol Particles Using X-ray Spectromicroscopy at the Carbon K-Edge

    SciTech Connect (OSTI)

    Moffet, Ryan C.; Henn, Tobias R.; Laskin, Alexander; Gilles, Marry K.

    2010-10-01

    We have developed an automated data analysis method for atmospheric particles using scanning transmission X-ray microscopy coupled with near edge X-ray fine structure spectroscopy (STXM/NEXAFS). This method is applied to complex internally mixed submicron particles containing organic and inorganic material. Several algorithms were developed to exploit NEXAFS spectral features in the energy range from 278-320 eV for quantitative mapping of the spatial distribution of elemental carbon, organic carbon, potassium, and non-carbonaceous elements in particles of mixed composition. This energy range encompasses the carbon K-edge and potassium L2 and L3 edges. STXM/NEXAFS maps of different chemical components were complemented with a subsequent analysis using elemental maps obtained by scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX). We demonstrate application of the automated mapping algorithms for data analysis and the statistical classification of particles.

  4. Constraints on jet X-ray emission in low/hard state X-ray binaries

    E-Print Network [OSTI]

    Thomas J. Maccarone

    2005-03-31

    We show that the combination of the similarities between the X-ray properties of low luminosity accreting black holes and accreting neutron stars, combined with the differences in their radio properties argues that the X-rays from these systems are unlikely to be formed in the relativistic jets. Specifically, the spectra of extreme island state neutron stars and low/hard state black holes are known to be indistinguishable, while the power spectra from these systems are known to show only minor differences beyond what would be expected from scaling the characteristic variability frequencies by the mass of the compact object. The spectral and temporal similarities thus imply a common emission mechanism that has only minor deviations from having all key parameters scaling linearly with the mass of the compact object, while we show that this is inconsistent with the observations that the radio powers of neutron stars are typically about 30 times lower than those of black holes at the same X-ray luminosity. We also show that an abrupt luminosity change would be expected when a system makes a spectral state transition from a radiatively inefficient jet dominated accretion flow to a thin disk dominated flow, but that such a change is not seen.

  5. A transient supergiant X-ray binary in IC 10: An extragalactic SFXT?

    SciTech Connect (OSTI)

    Laycock, Silas; Cappallo, Rigel; Oram, Kathleen; Balchunas, Andrew

    2014-07-01

    We report the discovery of a large amplitude (factor of ?100) X-ray transient (IC 10 X-2, CXOU J002020.99+591758.6) in the nearby dwarf starburst galaxy IC 10 during our Chandra monitoring project. Based on the X-ray timing and spectral properties, and an optical counterpart observed with Gemini, the system is a high-mass X-ray binary consisting of a luminous blue supergiant and a neutron star. The highest measured luminosity of the source was 1.8 × 10{sup 37} erg s{sup –1}during an outburst in 2003. Observations before, during, and after a second outburst in 2010 constrain the outburst duration to be less than 3 months (with no lower limit). The X-ray spectrum is a hard power law (? = 0.3) with fitted column density (N{sub H} = 6.3 × 10{sup 21} atom cm{sup –2}), consistent with the established absorption to sources in IC 10. The optical spectrum shows hydrogen Balmer lines strongly in emission at the correct blueshift (-340 km s{sup –1}) for IC 10. The N III triplet emission feature is seen, accompanied by He II [4686] weakly in emission. Together these features classify the star as a luminous blue supergiant of the OBN subclass, characterized by enhanced nitrogen abundance. Emission lines of He I are seen, at similar strength to H?. A complex of Fe II permitted and forbidden emission lines are seen, as in B[e] stars. The system closely resembles galactic supergiant fast X-ray transients, in terms of its hard spectrum, variability amplitude, and blue supergiant primary.

  6. X-rays from magnetically channeled winds of OB stars

    E-Print Network [OSTI]

    David H. Cohen

    2008-01-30

    OB stars with strong radiation-driven stellar winds and large-scale magnetic fields generate strong and hard X-ray emission via the Magnetically Channeled Wind Shock (MCWS) mechanism. In this brief paper, I describe four separate X-ray diagnostics of the MCWS mechanism in OB stars, with applications to the prototype young O star, theta-1 Ori C.

  7. Electromagnetic Application: X-RAY Alawi H. Ba-Surrah

    E-Print Network [OSTI]

    Masoudi, Husain M.

    , Pulyui published high-quality x-ray images in journals in Paris and London. · Nikola Tesla In April 1887, Nikola Tesla began to investigate X-rays using high voltages and tubes of his own design, as well. The principle behind Tesla's device is called the Bremsstrahlung process, in which a high-energy secondary X

  8. X-rays from Hot Stars: Stellar Astronomy Research with

    E-Print Network [OSTI]

    Cohen, David

    emission lines Hot stars*: massive outflows ("stellar winds") ­ are the x-rays associated with these winds can actually take an image of its "wind nebula" ­ in all other cases, we infer the presence of a wind a model for fitting the detailed shapes of x-ray emission line profiles from hot star winds The very hot

  9. National School on Neutron and X-ray Scattering

    E-Print Network [OSTI]

    15th National School on Neutron and X-ray Scattering August 10 - 24, 2013 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major Ridge National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang

  10. Thirteenth National School on Neutron and X-ray Scattering

    E-Print Network [OSTI]

    Thirteenth National School on Neutron and X-ray Scattering June 11 ­ June 25, 2011 at Argonne of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne

  11. Sixteenth National School on Neutron and X-ray Scattering

    E-Print Network [OSTI]

    Pennycook, Steve

    Sixteenth National School on Neutron and X-ray Scattering June 14-28, 2014 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major's Neutron Scattering Science Division. Scientific Directors: Suzanne G.E. te Velthuis, Esen Ercan Alp

  12. Neutron and X-ray Scattering Study of Magnetic Manganites

    E-Print Network [OSTI]

    Boothroyd, Andrew

    Neutron and X-ray Scattering Study of Magnetic Manganites Graeme Eoin Johnstone A Thesis submitted are performed using a variety of neutron scattering and x-ray scattering techniques. The electronic ground for analysing the results of the polarised neutron scattering experiment. There are a large number of people who

  13. National School on Neutron and X-ray Scattering

    E-Print Network [OSTI]

    Pennycook, Steve

    National School on Neutron and X-ray Scattering May 30 ­ June 13, 2009 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne

  14. Fourteenth National School on Neutron and X-ray Scattering

    E-Print Network [OSTI]

    Pennycook, Steve

    Fourteenth National School on Neutron and X-ray Scattering August 12 - 25, 2012 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major Ridge National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang

  15. Twelfth National School on Neutron and X-ray Scattering

    E-Print Network [OSTI]

    Pennycook, Steve

    Twelfth National School on Neutron and X-ray Scattering June 12 ­ June 26, 2010 at Argonne National of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne

  16. Tenth National School on Neutron and X-ray Scattering

    E-Print Network [OSTI]

    Pennycook, Steve

    Tenth National School on Neutron and X-ray Scattering September 24 - October 11, 2008 at Argonne of the National School on Neutron and X-ray Scattering is to educate graduate students on the utilization of major National Laboratory's Neutron Scattering Science Division. Scientific Directors: Jonathan C. Lang, Suzanne

  17. Millisecond oscillations during thermonuclear X-ray bursts

    E-Print Network [OSTI]

    Muno, Michael Patrick, 1975-

    2002-01-01

    I analyze 68 oscillation trains detected in a search of 159 thermonuclear bursts from eight neutron star X-ray binaries observed with the Rossi X-ray Timing Explorer. I use all data that were public as of September 2001. ...

  18. Microwave and hard X-ray imaging observations of

    E-Print Network [OSTI]

    White, Stephen

    Microwave and hard X-ray imaging observations of energetic electrons in solar flares: event of 2003 to nonthermal energies are seen via microwave and hard X-ray emission from the solar corona. Imaging sophisticated and fully dedicated solar radio telescope operating at microwave frequencies (17 & 34 GHz) capable

  19. Broadband high resolution X-ray spectral analyzer

    DOE Patents [OSTI]

    Silver, E.H.; Legros, M.; Madden, N.W.; Goulding, F.; Landis, D.

    1998-07-07

    A broad bandwidth high resolution X-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces X-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available X-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for X-ray microanalysis or in research applications such as laboratory and astrophysical X-ray and particle spectroscopy. 6 figs.

  20. ZAP! The X-Ray Laser is Born

    SciTech Connect (OSTI)

    Ratner, Daniel

    2009-11-17

    SLAC has converted its giant particle accelerator into the world's first X-ray laser. By a billion fold the world's brightest X-ray source, the laser packs a trillion photons into pulses as short as a millionth of a billionth of a second. The ultra-bright, ultra-short X-ray pulses will drive a wide range of new experiments, as scientists strip electrons from atoms, photograph single molecules and make movies of chemical reactions. How has SLAC accomplished such feats of X-ray wizardry? Attend this public lecture to learn about the basics of an X-ray laser, the technologies at SLAC that make it possible, and the exciting new experiments now underway.

  1. X-ray bang-time and fusion reaction history at ~ps resolution using RadOptic detection

    SciTech Connect (OSTI)

    Vernon, S P; Lowry, M E; Baker, K L; Bennett, C V; Celeste, J R; Cerjan, C; Haynes, S; Hernandez, V J; Hsing, W W; London, R A; Moran, B; von Wittenau, A S; Steele, P T; Stewart, R E

    2012-05-01

    We report recent progress in the development of RadOptic detectors, radiation to optical converters, that rely upon x-ray absorption induced modulation of the optical refractive index of a semiconductor sensor medium to amplitude modulate an optical probe beam. The sensor temporal response is determined by the dynamics of the electron-hole pair creation and subsequent relaxation in the sensor medium. Response times of a few ps have been demonstrated in a series of experiments conducted at the LLNL Jupiter Laser Facility. This technology will enable x-ray bang-time and fusion burn-history measurements with {approx} ps resolution.

  2. Theoretical X-ray Line Profiles from Colliding Wind Binaries

    E-Print Network [OSTI]

    D. B. Henley; I. R. Stevens; J. M. Pittard

    2003-06-23

    We present theoretical X-ray line profiles from a range of model colliding wind systems. In particular, we investigate the effects of varying the stellar mass-loss rates, the wind speeds, and the viewing orientation. We find that a wide range of theoretical line profile shapes is possible, varying with orbital inclination and phase. At or near conjunction, the lines have approximately Gaussian profiles, with small widths (HWHM ~ 0.1 v_\\infty) and definite blue- or redshifts (depending on whether the star with the weaker wind is in front or behind). When the system is viewed at quadrature, the lines are generally much broader (HWHM ~ v_\\infty), flat-topped and unshifted. Local absorption can have a major effect on the observed profiles - in systems with mass-loss rates of a few times 10^{-6} Msol/yr the lower energy lines (E wind of the primary. The orbital variation of the line widths and shifts is reduced in a low inclination binary. The extreme case is a binary with i = 0 degrees, for which we would expect no line profile variation.

  3. Interfacial Magnetism in Complex Oxide Heterostructures Probed by Neutrons and X-rays

    SciTech Connect (OSTI)

    Liu, Yaohua; Ke, Xianglin

    2015-01-01

    Magnetic complex-oxide heterostructures are of keen interest because a wealth of phenomena at the interface of dissimilar materials can give rise to fundamentally new physics and potentially valuable functionalities. Altered magnetization, novel magnetic coupling and emergent interfacial magnetism at the epitaxial layered-oxide interfaces have all been intensively investigated, which shapes our understanding on how to utilize those materials, particularly for spintronics. Neutron and x-ray based techniques have played a decisive role in characterizing interfacial magnetic structures and clarifying the underlying physics in this rapidly developing field. Here we review some recent experimental results, with an emphasis on those studied via polarized neutron reflectometery and polarized x-ray absorption spectroscopy. We conclude with some perspectives.

  4. Chemical Bonding in Aqueous Ferrocyanide: Experimental and Theoretical X-ray Spectroscopic Study

    E-Print Network [OSTI]

    Engel, Nicholas; Suljoti, Edlira; Garcia-Diez, Raul; Lange, Kathrin M; Atak, Kaan; Golnak, Ronny; Kothe, Alexander; Dantz, Marcus; Kühn, Oliver; Aziz, Emad F

    2013-01-01

    Resonant inelastic X-ray scattering (RIXS) and X-ray absorption (XA) experiments at the iron L- and nitrogen K-edge are combined with high-level first principles restricted active space self-consistent field (RASSCF) calculations for a systematic investigation of the nature of the chemical bond in potassium ferrocyanide in aqueous solution. The atom- and site-specific RIXS excitations allow for direct observation of ligand-to-metal (Fe L-edge) and metal-to-ligand (N K-edge) charge transfer bands and thereby evidence for strong {\\sigma}-donation and {\\pi}-back-donation. The effects are identified by comparing experimental and simulated spectra related to both the unoccupied and occupied molecular orbitals in solution.

  5. Ultrafast myoglobin structural dynamics observed with an X-ray free-electron laser

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Levantino, Matteo; Schirò, Giorgio; Lemke, Henrik Till; Cottone, Grazia; Glownia, James Michael; Zhu, Diling; Chollet, Mathieu; Ihee, Hyotcherl; KAIST, Daejeon; Cupane, Antonio; et al

    2015-04-02

    Light absorption can trigger biologically relevant protein conformational changes. The light induced structural rearrangement at the level of a photoexcited chromophore is known to occur in the femtosecond timescale and is expected to propagate through the protein as a quake-like intramolecular motion. Here we report direct experimental evidence of such ‘proteinquake’ observed in myoglobin through femtosecond X-ray solution scattering measurements performed at the Linac Coherent Light Source X-ray free-electron laser. An ultrafast increase of myoglobin radius of gyration occurs within 1 picosecond and is followed by a delayed protein expansion. As the system approaches equilibrium it undergoes damped oscillations withmore »a ~3.6-picosecond time period. Our results unambiguously show how initially localized chemical changes can propagate at the level of the global protein conformation in the picosecond timescale.« less

  6. MICROANALYSIS OF NY/NJ HARBOR SEDIMENTS USING SYNCHROTRON X-RAY BEAMS.

    SciTech Connect (OSTI)

    JONES,K.W.FENG,H.LANZIROTTI,A.MARINKOVIC,N.ET AL.

    2003-12-31

    Sediments found in the New York/New Jersey Harbor are widely contaminated with organic and inorganic compounds of anthropogenic origin. As a result, the environmental health of the Harbor has deteriorated and the efficient operation of the Port compromised by difficulties in disposing of sediments resulting from maintenance and improvements of navigational channels. Knowledge of the properties of the sediments on a micro-scale is useful in understanding the transport of contaminants through the environment, for developing effective methods for sediment decontamination, and for subsequent beneficial use of the cleaned sediments. We have investigated several properties of these sediments using synchrotron radiation techniques. These include computed microtomography using absorption and fluorescence contrast mechanisms, x-ray microscopy, microbeam x-ray fluorescence, and Fourier Transform Infrared Spectroscopy (FTIR) for measurements of microstructure, distribution of metals on individual sediment particles, and chemical forms of the contaminants on a micrometer scale. Typical results obtained with these techniques are presented.

  7. Bent Crystal X-Ray Mirrors for Time-Resolved Experiments with Femtosecond Laser-Produced X-ray Pulses

    E-Print Network [OSTI]

    von der Linde, D.

    Bent Crystal X-Ray Mirrors for Time-Resolved Experiments with Femtosecond Laser-Produced X@iep.physik.uni-essen.de Abstract. In the last few years, bent crystal X-ray mirrors have played an important role in time, for example, with the help of toroidally bent crystals which allow a monochromatic point-to-point imaging

  8. X-RAY EMISSION FROM PLANETS AND COMETS: RELATIONSHIP WITH SOLAR X-RAYS AND SOLAR WIND

    E-Print Network [OSTI]

    Bergen, Universitetet i

    X-RAY EMISSION FROM PLANETS AND COMETS: RELATIONSHIP WITH SOLAR X-RAYS AND SOLAR WIND ANIL BHARDWAJ extraterrestrische Physik, Garching, Germany 6 Applied Physics Laboratory, John Hopkins University, Laurel, MD 20723 planets Jupiter and Saturn in the energy range of 0.2-2 keV. These flares are found to occur in tandem

  9. Millimeter, Microwave, Hard X--ray and Soft X--ray Observations of Energetic Electron Populations in Solar Flares

    E-Print Network [OSTI]

    White, Stephen

    Millimeter, Microwave, Hard X--ray and Soft X--ray Observations of Energetic Electron Populations in Solar Flares M. R. Kundu 1 , S. M. White 1 , N. Gopalswamy 1 and J. Lim 1,2 1 Dept. of Astronomy, Univ. of Maryland, College Park MD 20742 2 Solar Astronomy 264--33, Caltech, Pasadena CA 91125 Submitted

  10. Deep x-ray lithography for micromechanics

    SciTech Connect (OSTI)

    Christenson, T.R. [Sandia National Labs., Albuquerque, NM (United States); Guckel, H. [Wisconsin Univ., Madison, WI (United States). Dept. of Electrical and Computer Engineering

    1995-08-01

    Extensions of the German LIGA process have brought about fabrication capability suitable for cost effective production of precision engineered components. The process attributes allow fabrication of mechanical components which are not capable of being made via conventional subtractive machining methods. Two process improvements have been responsible for this extended capability which involve the areas of thick photoresist application and planarization via precision lapping. Application of low-stress x-ray photoresist has been achieved using room temperature solvent bonding of a preformed photoresist sheet. Precision diamond lapping and polishing has provided a flexible process for the planarization of a wide variety of electroplated metals in the presence of photoresist. Exposure results from the 2.5 GeV National Synchrotron Light Source storage ring at Brookhaven National Laboratory have shown that structural heights of several millimeter and above are possible. The process capabilities are also well suited for microactuator fabrication. Linear and rotational magnetic microactuators have been constructed which use coil winding technology with LIGA fabricated coil forms. Actuator output forces of 1 milliNewton have been obtained with power dissipation on the order of milliWatts. A rotational microdynamometer system which is capable of measuring torque-speed data is also discussed.

  11. X-ray spectral states of microquasars

    E-Print Network [OSTI]

    Julien Malzac; Renaud Belmont

    2008-10-25

    We discuss the origin of the dramatically different X-ray spectral shapes observed in the Low Hard State (LHS: dominated by thermal comptonisation) and the High Soft State (HSS: dominated by the accretion disc thermal emission and non-thermal comptonisation in the corona). We present numerical simulations using a new code accounting for the so-called synchrotron boiler effect. These numerical simulations when compared to the data allow us to constrain the magnetic field and temperature of the hot protons in the corona. For the hard state of Cygnus X-1 we find a magnetic field below equipartition with radiation, suggesting that the corona is not powered through magnetic field dissipation (as assumed in most accretion disc corona models). On the other hand, our results also point toward proton temperatures that are substantially lower than typical temperatures of the ADAF models. Finally, we show that in both spectral states Comptonising plasma could be powered essentially through power-law acceleration of non-thermal electrons, which are then partly thermalised by the synchrotron and Coulomb boiler. This suggests that, contrary to current beliefs, the corona of the HSS and that of the LHS could be of very similar nature. The differences between the LHS and HSS coronal spectra would then be predominantly caused by the strong disc soft cooling emission which is present in the HSS and absent in the LHS.

  12. A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

    SciTech Connect (OSTI)

    Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; Vo, Huy; Uervirojnangkoorn, Monarin; Brunger, Axel T.; Berger, James M.

    2015-08-11

    Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. In addition, the features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.

  13. X-ray diffraction in the pulsed laser heated diamond anvil cell

    SciTech Connect (OSTI)

    Goncharov, Alexander F.; Struzhkin, Viktor V.; Dalton, D. Allen; Prakapenka, Vitali B.; Kantor, Innokenty; Rivers, Mark L.

    2010-11-15

    We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell at pressure up to 60 GPa. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 {mu}s pulse width synchronized with a gated x-ray detector (Pilatus) and time-resolved radiometric temperature measurements. This enables the time domain measurements as a function of temperature in a microsecond time scale (averaged over many events, typically more than 10 000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration, samples 4 {mu}m thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformities as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. This delicate control, which may also prevent chemical reactivity and diffusion, enables accurate measurement of melting curves, phase changes, and thermal equations of state.

  14. NEW X-RAY DETECTIONS OF WNL STARS

    SciTech Connect (OSTI)

    Skinner, Stephen L.; Zhekov, Svetozar A.; Guedel, Manuel; Schmutz, Werner; Sokal, Kimberly R.

    2012-05-15

    Previous studies have demonstrated that putatively single nitrogen-type Wolf-Rayet stars (WN stars) without known companions are X-ray sources. However, almost all WN star X-ray detections so far have been of earlier WN2-WN6 spectral subtypes. Later WN7-WN9 subtypes (also known as WNL stars) have proved more difficult to detect, an important exception being WR 79a (WN9ha). We present here new X-ray detections of the WNL stars WR 16 (WN8h) and WR 78 (WN7h). These new results, when combined with previous detections, demonstrate that X-ray emission is present in WN stars across the full range of spectral types, including later WNL stars. The two WN8 stars observed to date (WR 16 and WR 40) show unusually low X-ray luminosities (L{sub x} ) compared to other WN stars, and it is noteworthy that they also have the lowest terminal wind speeds (v{sub {infinity}}). Existing X-ray detections of about a dozen WN stars reveal a trend of increasing L{sub x} with wind luminosity L{sub wind} = (1/2)M-dot v{sup 2}{sub {infinity}}, suggesting that wind kinetic energy may play a key role in establishing X-ray luminosity levels in WN stars.

  15. NSLS-II X-Ray Diagnostics Development

    SciTech Connect (OSTI)

    ILINSKI, P.

    2011-03-28

    NSLS-II x-ray diagnostics will provide continuous online data of electron beam dimensions, which will be used to derive electron beam emittance and energy spread. It will also provide information of electron beam tilt for coupling evaluation. X-ray diagnostics will be based on imaging of bending magnet and three-pole wiggler synchrotron radiation sources. Diagnostics from three-pole wiggler source will be used to derive particles energy spread. Beta and dispersion functions will have to be evaluated for emittance and particles energy spread calculations. Due to small vertical source sizes imaging need to be performed in x-ray energy range. X-ray optics with high numerical aperture, such as compound refractive lens, will be used to achieve required spatial resolution. Optical setups with different magnifications in horizontal and vertical directions fill be employed to deal with large aspect ratio of the source. X-ray diagnostics setup will include x-ray imaging optics, monochromatization, x-ray imaging and recording components.

  16. Spatially Extended 21 cm Signal from Strongly Clustered UV and X-Ray Sources in the Early Universe

    E-Print Network [OSTI]

    Ahn, Kyungjin; Norman, Michael L; Alvarez, Marcelo A; Wise, John H

    2014-01-01

    We present our prediction for the local 21 cm differential brightness temperature ($\\delta T_{b}$) from a set of strongly clustered sources of Population III (Pop III) and II (Pop II) objects in the early Universe, by a numerical simulation of their formation and radiative feedback. These objects are located inside a highly biased environment, which is a rare, high-density peak ("Rarepeak") extending to $\\sim7$ comoving Mpc. We study the impact of ultraviolet (UV) and X-ray photons on the intergalactic medium (IGM) and the resulting $\\delta T_{b}$, when Pop III stars are assumed to emit X-ray photons by forming X-ray binaries after their death. We parameterize the rest-frame spectral energy density (SED) of X-ray photons, which regulates X-ray photon-trapping, IGM-heating, secondary Lyman-alpha pumping and the resulting morphology of $\\delta T_{b}$. A combination of emission ($\\delta T_{b}>0$) and absorption ($\\delta T_{b}<0$) regions appears in varying amplitudes and angular scales. The boost of the signa...

  17. A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; Vo, Huy; Uervirojnangkoorn, Monarin; Brunger, Axel T.; Berger, James M.

    2015-08-11

    Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (more »to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (« less

  18. Apparatus for generating x-ray holograms

    DOE Patents [OSTI]

    Rhodes, C.K.; Boyer, K.; Solem, J.C.; Haddad, W.S.

    1990-09-11

    Apparatus for x-ray microholography of living biological materials. A Fourier transform holographic configuration is described as being most suitable for the 3-dimensional recording of the physical characteristics of biological specimens. The use of a spherical scatterer as a reference and a charge-coupled device two-dimensional detector array placed in the forward direction relative to the incident x-radiation for viewing electromagnetic radiation simultaneously scattered from both the specimen and the reference scatterer permits the ready reconstruction of the details of the specimen from the fringe pattern detected by the charge-coupled device. For example, by using a nickel reference scatter at 4.5 nm, sufficient reference illumination is provided over a wide enough angle to allow similar resolution in both transverse and longitudinal directions. Both laser and synchrotron radiation sources are feasible for generating microholographs. Operation in the water window (2.4 to 4.5 nm) should provide maximum contrast for features of the specimen and spatial resolution on the order of the wavelength of x-radiation should be possible in all three dimensions, which is sufficient for the visualization of many biological features. It is anticipated that the present apparatus will find utility in other areas as well where microscopic physical details of a specimen are important. A computational procedure which enables the holographic data collected by the detector to be used to correct for misalignments introduced by inexact knowledge of the relative positions of the spherical reference scatterer and the sample under investigation has been developed. If the correction is performed prior to reconstruction, full compensation can be achieved and a faithfully reconstructed image produced. 7 figs.

  19. Apparatus for generating x-ray holograms

    DOE Patents [OSTI]

    Rhodes, Charles K. (Chicago, IL); Boyer, Keith (Los Alamos, NM); Solem, Johndale C. (Los Alamos, NM); Haddad, Waleed S. (Chicago, IL)

    1990-01-01

    Apparatus for x-ray microholography of living biological materials. A Fourier transform holographic configuration is described as being most suitable for the 3-dimensional recording of the physical characteristics of biological specimens. The use of a spherical scatterer as a reference and a charge-coupled device two-dimensional detector array placed in the forward direction relative to the incident x-radiation for viewing electromagnetic radiation simultaneously scattered from both the specimen and the reference scatterer permits the ready reconstruction of the details of the specimen from the fringe pattern detected by the charge-coupled device. For example, by using a nickel reference scatter at 4.5 nm, sufficient reference illumination is provided over a wide enough angle to allow similar resolution in both transverse and longitudinal directions. Both laser and synchrotron radiation sources are feasible for generating microholographs. Operation in the water window (2.4 to 4.5 nm) should provide maximum contrast for features of the specimen and spatial resolution on the order of the wavelength of x-radiation should be possible in all three dimensions, which is sufficient for the visualization of many biological features. It is anticipated that the present apparatus will find utility in other areas as well where microscopic physical details of a specimen are important. A computational procedure which enables the holographic data collected by the detector to be used to correct for misalignments introduced by inexact knowledge of the relative positions of the spherical reference scatterer and the sample under investigation has been developed. If the correction is performed prior to reconstruction, full compensation can be achieved and a faithfully reconstructed image produced.

  20. Characterization of X-ray generator beam profiles.

    SciTech Connect (OSTI)

    Mitchell, Dean J; Harding, Lee T.; Thoreson, Gregory G.; Theisen, Lisa Anne; Parmeter, John Ethan; Thompson, Kyle Richard

    2013-07-01

    T to compute the radiography properties of various materials, the flux profiles of X-ray sources must be characterized. This report describes the characterization of X-ray beam profiles from a Kimtron industrial 450 kVp radiography system with a Comet MXC-45 HP/11 bipolar oil-cooled X-ray tube. The empirical method described here uses a detector response function to derive photon flux profiles based on data collected with a small cadmium telluride detector. The flux profiles are then reduced to a simple parametric form that enables computation of beam profiles for arbitrary accelerator energies.

  1. X-ray backscatter imaging of nuclear materials

    DOE Patents [OSTI]

    Chapman, Jeffrey Allen; Gunning, John E; Hollenbach, Daniel F; Ott, Larry J; Shedlock, Daniel

    2014-09-30

    The energy of an X-ray beam and critical depth are selected to detect structural discontinuities in a material having an atomic number Z of 57 or greater. The critical depth is selected by adjusting the geometry of a collimator that blocks backscattered radiation so that backscattered X-ray originating from a depth less than the critical depth is not detected. Structures of Lanthanides and Actinides, including nuclear fuel rod materials, can be inspected for structural discontinuities such as gaps, cracks, and chipping employing the backscattered X-ray.

  2. Optical and X-ray Variability of Blazars

    E-Print Network [OSTI]

    Gupta, A C

    2015-01-01

    Here we report our recent results of variability studies in optical and X-ray bands of three blazars namely 3C 273, PKS 2155 - 304 and BL Lacertae with XMM-Newton. We found large amplitude optical to X-rays variability in 3C 273, and PKS 2155 - 304 on year time scale. In 3C 273, we noticed that synchrotron cooling and particle acceleration are at work at different epoch of observations. In PKS 2155 - 304, spectral energy distribution from optical to X-ray is fitted with LPPL (log parabolic + power law) model. In BL Lacertae, optical flux and degree of polarization were anti-correlated.

  3. Spatiotemporal focusing dynamics in plasmas at X-ray wavelength

    SciTech Connect (OSTI)

    Sharma, A., E-mail: a-physics2001@yahoo.com; Tibai, Z. [Institute of Physics, University of Pecs, Pecs–7624 (Hungary)] [Institute of Physics, University of Pecs, Pecs–7624 (Hungary); Hebling, J. [Institute of Physics, University of Pecs, Pecs–7624 (Hungary) [Institute of Physics, University of Pecs, Pecs–7624 (Hungary); Szentagothai Research Centre, University of Pecs, Pecs-7624 (Hungary); Mishra, S. K. [Institute for Plasma Research, Gandhinagar (India)] [Institute for Plasma Research, Gandhinagar (India)

    2014-03-15

    Using a finite curvature beam, we investigate here the spatiotemporal focusing dynamics of a laser pulse in plasmas at X-ray wavelength. We trace the dependence of curvature parameter on the focusing of laser pulse and recognize that the self-focusing in plasma is more intense for the X-ray laser pulse with curved wavefront than with flat wavefront. The simulation results demonstrate that spatiotemporal focusing dynamics in plasmas can be controlled with the appropriate choice of beam-plasma parameters to explore the high intensity effects in X-ray regime.

  4. X-ray afterglows from gamma-ray bursts

    E-Print Network [OSTI]

    M. Tavani

    1997-03-24

    We consider possible interpretations of the recently detected X- ray afterglow from the gamma-ray burst source GRB 970228. Cosmological and Galactic models of gamma-ray bursts predict different flux and spectral evolution of X-ray afterglows. We show that models based on adiabatic expansion of relativistic forward shocks require very efficient particle energization or post-burst re-acceleration during the expansion. Cooling neutron star models predict a very distinctive spectral and flux evolution that can be tested in current X-ray data.

  5. Laser-Produced Coherent X-Ray Sources

    SciTech Connect (OSTI)

    Donald Umstadter

    2007-01-31

    We study the generation of x-rays from the interaction of relativistic electrons with ultra-intense laser pulse either directly or via laser generated ion channels. The laser pulse acts as the accelerator and wiggler leading to an all-optical synchrotron-like x-ray source. The mm sized accelerator and micron-sized wiggler leads to a compact source of high brightness, ultrafast x-rays with applications in relativistic nonlinear optics, ultrafast chemistry, biology, inner-shell electronic processes and phase transitions.

  6. X-Ray Diffraction Microscopy of Magnetic Structures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWind Power >X-RayX-RayX-Ray

  7. Radiation exposure in X-ray-based imaging techniques used in osteoporosis

    E-Print Network [OSTI]

    Damilakis, John; Adams, Judith E.; Guglielmi, Giuseppe; Link, Thomas M.

    2010-01-01

    and nonradiologists in dual-energy X-ray absorptiometrymorphometry studies using dual-energy X-ray absorptiometry.dose measurements in dual energy X-ray absorptiometry (DXA).

  8. X-ray optics metrology limited by random noise, instrumental drifts, and systematic errors

    E-Print Network [OSTI]

    Yashchuk, Valeriy V.

    2010-01-01

    X-ray optics metrology limited by random noise, instrumentalUSA Center for X-ray Optics, Lawrence Berkeley Nationaland reflecting x-ray optics suitable for micro- and nano-

  9. Beyond 3-D X-ray Imaging: Methodology Development and Applications...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to the availability of the new generation of X-ray sources and the advanced X-ray optics. The advanced X-ray Optics along with novel methodology has made it possible to...

  10. Automated suppression of errors in LTP-II slope measurements with x-ray optics

    E-Print Network [OSTI]

    Ali, Zulfiqar

    2011-01-01

    slope measurements with x-ray optics Zulfiqar Ali, Curtis L.with state-of-the-art x-ray optics. Significant suppressionscanning, metrology of x-ray optics, deflectometry Abstract

  11. Synchrotron X-ray Scattering Studies of Rapidly Evolving Nanoscale Interfacial Systems /

    E-Print Network [OSTI]

    Dai, Yeling

    2013-01-01

    Stanley. X-ray and neutron scattering from rough surfaces.Stanley. X-ray and neutron scattering from rough surfaces.grazing incidence x-ray and neutron scattering from ordered

  12. Analysis of Order Formation in Block Copolymer Thin Films Using Resonant Soft X-Ray Scattering

    E-Print Network [OSTI]

    Virgili, Justin M.; Tao, Yuefei; Kortright, Jeffrey B.; Balsara, Nitash P.; Segalman, Rachel A.

    2006-01-01

    Methods of X-Ray and Neutron Scattering in Polymer Science.µ t for X-ray and neutron scattering experiments is unity;18 In classical scattering of light, X-rays or neutrons the

  13. X-ray scattering studies of structure and dynamics of surfaces and interfaces of polymeric liquids

    E-Print Network [OSTI]

    Jiang, Zhang

    2007-01-01

    Evanescent X-ray and Neutron Scattering. Springer-Verlag,Methods of X-ray and neutron scattering in polymer science.Stanley. X-ray and neutron scattering from rough surfaces.

  14. Imaging nanoscale magnetic structures with polarized soft x-ray photons

    E-Print Network [OSTI]

    Fischer, P.

    2010-01-01

    with polarized soft X-ray photons Peter Fischer and Mi -polarized soft X-ray photons which provide a strong X-rayhigh intense soft X-ray photon pulses hold the promise of

  15. A New Scheme for Stigmatic X-ray Imaging with Large Magnification...

    Office of Scientific and Technical Information (OSTI)

    F; Beiersdorfer, P; Wang, E; Sanchez del Rio, M; Caughey, T A 70 PLASMA PHYSICS AND FUSION TECHNOLOGY X-ray Imaging X-ray Imaging This paper describes a new x-ray scheme for...

  16. Achieving hard X-ray nanofocusing using a wedged multilayer Laue...

    Office of Scientific and Technical Information (OSTI)

    anticipate that continuous development on wedged MLLs will advance x-ray nanofocusing optics to new frontiers and enrich capabilities and opportunities for hard X-ray microscopy....

  17. Phase Tomography Using X-ray Talbot Interferometer

    SciTech Connect (OSTI)

    Momose, A.; Yashiro, W.; Moritake, M. [Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Takeda, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Uesugi, K.; Suzuki, Y. [SPring-8/JASRI, 1-1-1 Kouto, Mikazuki, Hyogo 679-5198 (Japan); Hattori, T. [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigori, Hyogo 678-1205 (Japan)

    2007-01-19

    A biological tomography result obtained with an X-ray Talbot interferometer is reported. An X-ray Talbot interferometer was constructed using an amplitude grating fabricated by X-ray lithography at the LIGA beamline of NewSUBARU and gold electroplating. The pitch and pattern thickness of the grating were 8 {mu}m and 30 {mu}m, respectively. The effective area was 20 x 20 mm2, which was entirely illuminated with a wide beam available at the medium-length beamline 20B2 of SPring-8, allowing the acquisition of a three-dimensional tomogram of almost the whole body of a fish. The resulting image obtained with 17.7 keV X-rays revealed organs with bones in the same view.

  18. Performance enhancement approaches for a dual energy x-ray

    E-Print Network [OSTI]

    Fu, Kenneth

    2010-01-01

    Evans, J.P.O. , “Stereoscopic dual energy imaging for targetCrawford, C.R. , “Dual Energy Volumetric X-ray Tomographicimages in 4–10 MeV Dual- energy customs system for material

  19. X-ray emission from the terrestrial magnetosheath

    E-Print Network [OSTI]

    Robertson, Ina Picket; Cravens, Thomas Edward

    2003-04-29

    [1] X-rays are generated throughout the terrestrial magnetosheath as a consequence of charge transfer collisions between heavy solar wind ions and geocoronal neutrals. The solar wind ions resulting from these collisions are left in highly excited...

  20. Active pixel sensors for X-ray astronomy

    E-Print Network [OSTI]

    Cohen, Matthew (Matthew L.)

    2005-01-01

    An active pixel sensor array, APS-1, has been fabricated for the purpose of scientific x-ray detection. This thesis presents the results of testing the device. Alternate design architectures are explored. Recommendations ...

  1. Accreting X-ray millisecond pulsars observed with INTEGRAL

    E-Print Network [OSTI]

    Maurizio Falanga

    2007-11-07

    I review the properties of three X-ray accreting millisecond pulsars observed with INTEGRAL. Out of seven recently discovered accretion-powered pulsars (one discovered by INTEGRAL), three were observed with the INTEGRAL satellite up to 300 keV. Detailed timing and spectral results will be presented, including data obtained during the most recent outburst of the pulsar HETE J1900.1-2455. Accreting X-ray millisecond pulsars are key systems to understand the spin and accretion history of neutron stars. They are also a good laboratory in which to study the source spectra, pulse profile, and phase shift between X-ray pulses in different energy ranges which give additional information of the X-ray production processes and emission environment.

  2. Magnetically Confined Wind Shocks in X-rays - a Review

    E-Print Network [OSTI]

    ud-Doula, Asif

    2015-01-01

    A subset (~ 10%) of massive stars present strong, globally ordered (mostly dipolar) magnetic fields. The trapping and channeling of their stellar winds in closed magnetic loops leads to magnetically confined wind shocks (MCWS), with pre-shock flow speeds that are some fraction of the wind terminal speed. These shocks generate hot plasma, a source of X-rays. In the last decade, several developments took place, notably the determination of the hot plasma properties for a large sample of objects using XMM-Newton and Chandra, as well as fully self-consistent MHD modelling and the identification of shock retreat effects in weak winds. Despite a few exceptions, the combination of magnetic confinement, shock retreat and rotation effects seems to be able to account for X-ray emission in massive OB stars. Here we review these new observational and theoretical aspects of this X-ray emission and envisage some perspectives for the next generation of X-ray observatories.

  3. Systems and methods for detecting x-rays

    DOE Patents [OSTI]

    Bross, Alan D.; Mellott, Kerry L.; Pla-Dalmau, Anna

    2006-05-02

    Systems and methods for detecting x-rays are disclosed herein. One or more x-ray-sensitive scintillators can be configured from a plurality of heavy element nano-sized particles and a plastic material, such as polystyrene. As will be explained in greater detail herein, the heavy element nano-sized particles (e.g., PbWO4) can be compounded into the plastic material with at least one dopant that permits the plastic material to scintillate. X-rays interact with the heavy element nano-sized particles to produce electrons that can deposit energy in the x-ray sensitive scintillator, which in turn can produce light.

  4. X-ray obscuration in local Universe AGN

    E-Print Network [OSTI]

    Matteo Guainazzi

    2006-10-31

    I review the constraints that X-ray observations impose on the physical properties and the geometrical distribution of cold absorbing gas in nearby obscured Active Galactic Nuclei (AGN), as well as their implications for AGN structure models.

  5. Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    interpretation of XMLD data. Magnetism and X Rays The ancient Greeks and also the Chinese knew about strange and rare stones with the power to attract iron. Moreover, when...

  6. The Ulysses Catalog of Solar Hard X-Ray Flares

    E-Print Network [OSTI]

    Tranquille, C.; Hurley, K.; Hudson, H. S.

    2009-01-01

    Sturrock, P.A. (ed. ) Solar Flares: A Monograph from SkylabSmith E.V.P. : 1963, Solar Flares, Macmillan, New York.Catalog of Solar Hard X-Ray Flares Table 1 (Continued. )

  7. Using Light to Control How X Rays Interact with Matter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Using Light to Control How X Rays Interact with Matter Print Schemes that use one light pulse to manipulate interactions of another with matter are well developed in the...

  8. X-Ray Propagation in Tapered Waveguides: Simulation and Optimization

    E-Print Network [OSTI]

    Peinke, Joachim

    [1,2]. X-ray waveguides (WG) have been designed and fabricated as planar layered systems (1D-WG) [3. The propagation in the stuctures is studied by numerical solution of the parabolic wave equation (PWE), as used

  9. Generation of Coherent X-Ray Radiation through Modulation Compression...

    Office of Scientific and Technical Information (OSTI)

    In this paper, we propose a scheme to generate tunable coherent X-ray radiation for future light source applications. This scheme uses an energy chirped electron beam, a laser...

  10. Towards attosecond X-ray pulses from the FEL

    E-Print Network [OSTI]

    Zholents, Alexander A.; Fawley, William M.

    2004-01-01

    can be used instead of HC FEL. In the following illustra-UM is now tuned for resonant FEL interaction with the 32-nmAttosecond X-Ray Pulses from the FEL Alexander A. Zholents,

  11. High performance x-ray anti-scatter grid

    DOE Patents [OSTI]

    Logan, C.M.

    1995-05-23

    Disclosed are an x-ray anti-scatter grid for x-ray imaging, particularly for screening mammography, and method for fabricating same, x-rays incident along a direct path pass through a grid composed of a plurality of parallel or crossed openings, microchannels, grooves, or slots etched in a substrate, such as silicon, having the walls of the microchannels or slots coated with a high opacity material, such as gold, while x-rays incident at angels with respect to the slots of the grid, arising from scatter, are blocked. The thickness of the substrate is dependent on the specific application of the grid, whereby a substrate of the grid for mammography would be thinner than one for chest radiology. Instead of coating the walls of the slots, such could be filed with an appropriate liquid, such as mercury. 4 Figs.

  12. Vitreous carbon mask substrate for X-ray lithography

    DOE Patents [OSTI]

    Aigeldinger, Georg (Livermore, CA); Skala, Dawn M. (Fremont, CA); Griffiths, Stewart K. (Livermore, CA); Talin, Albert Alec (Livermore, CA); Losey, Matthew W. (Livermore, CA); Yang, Chu-Yeu Peter (Dublin, CA)

    2009-10-27

    The present invention is directed to the use of vitreous carbon as a substrate material for providing masks for X-ray lithography. The new substrate also enables a small thickness of the mask absorber used to pattern the resist, and this enables improved mask accuracy. An alternative embodiment comprised the use of vitreous carbon as a LIGA substrate wherein the VC wafer blank is etched in a reactive ion plasma after which an X-ray resist is bonded. This surface treatment provides a surface enabling good adhesion of the X-ray photoresist and subsequent nucleation and adhesion of the electrodeposited metal for LIGA mold-making while the VC substrate practically eliminates secondary radiation effects that lead to delamination of the X-ray resist form the substrate, the loss of isolated resist features, and the formation of a resist layer adjacent to the substrate that is insoluble in the developer.

  13. High order reflectivity of graphite (HOPG) crystals for x ray...

    Office of Scientific and Technical Information (OSTI)

    (22.1 keV) x-rays, produced by petawatt class laser pulses interacting with a Kr gas jet and a silver foil, to measure the integrated crystal reflectivity of flat Highly...

  14. X-ray imaging reveals secrets in battery materials | Argonne...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    X-ray imaging reveals secrets in battery materials June 22, 2015 Tweet EmailPrint Imaging and data analysis techniques offer new approach to probing material properties In a new...

  15. Discovery of Non-Thermal X-Rays from the Shell of RCW86

    E-Print Network [OSTI]

    Aya Bamba; Katsuji Koyama; Hiroshi Tomida

    2000-08-16

    We report the ASCA (Advanced Satellite for Cosmology and Astrophysics) results of RCW 86, a shell-like supernova remnant (SNR). The bright region in the X-ray band traces the radio clumpy shell, although details of the structure are different. The X-ray spectrum from each part of the shell can not be fitted to a thin thermal plasma model, but requires, at least three components: a low temperature plasma of 0.3 keV, high temperature plasma of > several keV, and a power-law component with a photon index = 3. The abundances of O, Ne, Mg and Si are significantly higher than that of Fe, indicating that RCW 86 is a type II SNR. The absorption column of 3e21 H cm^-2 indicates the distance to the SNR to be several kpc. The power-law component can be interpreted to be synchrotron radiation of high energy electrons. Assuming energy density equipartition between the magnetic field and the electrons, and using the radio and X-ray spectra, we argue that high energy electrons are accelerated up to 20 TeV. The acceleration efficiency is, however, different from shell to shell.

  16. Hard x-ray transmission crystal spectrometer at the OMEGA-EP laser facility

    SciTech Connect (OSTI)

    Seely, J. F.; Szabo, C. I.; Feldman, U.; Hudson, L. T.; Henins, A.; Audebert, P.; Brambrink, E.

    2010-10-15

    The transmission crystal spectrometer (TCS) is approved for taking data at the OMEGA-EP laser facility since 2009 and will be available for the OMEGA target chamber in 2010. TCS utilizes a Cauchois type cylindrically bent transmission crystal geometry with a source to crystal distance of 600 mm. Spectral images are recorded by image plates in four positions, one IP on the Rowland circle and three others at 200, 400, and 600 mm beyond the Rowland circle. An earlier version of TCS was used at LULI on experiments that determined the x-ray source size from spectral line broadening on one IP positioned behind the Rowland circle. TCS has recorded numerous backlighter spectra at EP for point projection radiography and for source size measurements. Hard x-ray source size can be determined from the source broadening of both K shell emission lines and from K absorption edges in the bremsstrahlung continuum, the latter being a new way to measure the spatial extent of the hard x-ray bremsstrahlung continuum.

  17. Can photo-ionization explain the decreasing fraction of X-ray obscured AGN with luminosity?

    E-Print Network [OSTI]

    A. Akylas; I. Georgantopoulos

    2008-01-30

    Chandra and XMM surveys show that the fraction of obscured AGN decreases rapidly with increasing luminosity. Although this is usually explained by assuming that the covering factor of the central engine is much smaller at luminous QSOs, the exact origin of this effect remains unknown. We perform toy simulations to test whether photo-ionisation of the obscuring screen in the presence of a strong radiation field can reproduce this effect. In particular, we create X-ray spectral simulations using a warm absorber model assuming a range of input column densities and ionization parameters. We fit instead the simulated spectra with a simple cold absorption power-law model that is the standard practice in X-ray surveys. We find that the fraction of absorbed AGN should fall with luminosity as $L^{-0.16\\pm0.03}$ in rough agreement with the observations. Furthermore, this apparent decrease in the obscuring material is consistent with the dependence of the FeK$\\alpha$ narrow-line equivalent width on luminosity, ie. the X-ray Baldwin effect.

  18. An X-ray variable absorber within the Broad Line Region in Fairall 51

    E-Print Network [OSTI]

    Svoboda, Jiri; Guainazzi, Matteo; Longinotti, Anna Lia; Piconcelli, Enrico; Wilms, Joern

    2015-01-01

    Fairall 51 is a polar-scattered Seyfert 1 galaxy, a type of active galaxies believed to represent a bridge between unobscured type-1 and obscured type-2 objects. Fairall 51 has shown complex and variable X-ray absorption but only little is known about its origin. In our research, we observed Fairall 51 with the X-ray satellite Suzaku in order to constrain a characteristic time-scale of its variability. We performed timing and spectral analysis of four observations separated by 1.5, 2 and 5.5 day intervals. We found that the 0.5-50 keV broadband X-ray spectra are dominated by a primary power-law emission (with the photon index ~ 2). This emission is affected by at least three absorbers with different ionisations (log(xi) ~ 1-4). The spectrum is further shaped by a reprocessed emission, possibly coming from two regions -- the accretion disc and a more distant scattering region. The accretion disc emission is smeared by the relativistic effects, from which we measured the spin of the black hole as a ~ 0.8 (+-0.2...

  19. Suzaku Observation of Diffuse X-ray Emission from the Carina Nebula

    E-Print Network [OSTI]

    Hamaguchi, K; Matsumoto, H; Tsujimoto, M; Holt, S S; Ezoe, Y; Ozawa, H; Tsuboi, Y; Soong, Y; Kitamoto, S; Sekiguchi, A; Kokubun, M; Hamaguchi, Kenji; Petre, Robert; Matsumoto, Hironori; Tsujimoto, Masahiro; Holt, Stephan S.; Ezoe, Yuichiro; Ozawa, Hideki; Tsuboi, Yohko; Soong, Yang; Kitamoto, Shunji; Sekiguchi, Akiko; Kokubun, Motohide

    2006-01-01

    We studied extended X-ray emission from the Carina Nebula taken with the Suzaku CCD camera XIS on 2005 Aug. 29. The X-ray morphology, plasma temperature and absorption to the plasma are consistent with the earlier Einstein results. The Suzaku spectra newly revealed emission lines from various species including oxygen, but not from nitrogen. This result restricts the N/O ratio significantly low, compared with evolved massive stellar winds, suggesting that the diffuse emission is originated in an old supernova remnant or a super shell produced by multiple supernova remnants. The X-ray spectra from the north and south of Eta Carinae showed distinct differences between 0.3-2 keV. The south spectrum shows strong L-shell lines of iron ions and K-shell lines of silicon ions, while the north spectrum shows them weak in intensity. This means that silicon and iron abundances are a factor of 2-4 higher in the south region than in the north region. The abundance variation may be produced by an SNR ejecta, or relate to th...

  20. Suzaku Observation of Diffuse X-ray Emission from the Carina Nebula

    E-Print Network [OSTI]

    Kenji Hamaguchi; Robert Petre; Hironori Matsumoto; Masahiro Tsujimoto; Stephan S. Holt; Yuichiro Ezoe; Hideki Ozawa; Yohko Tsuboi; Yang Soong; Shunji Kitamoto; Akiko Sekiguchi; Motohide Kokubun

    2006-10-02

    We studied extended X-ray emission from the Carina Nebula taken with the Suzaku CCD camera XIS on 2005 Aug. 29. The X-ray morphology, plasma temperature and absorption to the plasma are consistent with the earlier Einstein results. The Suzaku spectra newly revealed emission lines from various species including oxygen, but not from nitrogen. This result restricts the N/O ratio significantly low, compared with evolved massive stellar winds, suggesting that the diffuse emission is originated in an old supernova remnant or a super shell produced by multiple supernova remnants. The X-ray spectra from the north and south of Eta Carinae showed distinct differences between 0.3-2 keV. The south spectrum shows strong L-shell lines of iron ions and K-shell lines of silicon ions, while the north spectrum shows them weak in intensity. This means that silicon and iron abundances are a factor of 2-4 higher in the south region than in the north region. The abundance variation may be produced by an SNR ejecta, or relate to the dust formation around the star forming core.

  1. Dose optimization in cardiac x-ray imaging

    SciTech Connect (OSTI)

    Gislason-Lee, Amber J.; McMillan, Catherine; Cowen, Arnold R.; Davies, Andrew G.

    2013-09-15

    Purpose: The aim of this research was to optimize x-ray image quality to dose ratios in the cardiac catheterization laboratory. This study examined independently the effects of peak x-ray tube voltage (kVp), copper (Cu), and gadolinium (Gd) x-ray beam filtration on the image quality to radiation dose balance for adult patient sizes.Methods: Image sequences of polymethyl methacrylate (PMMA) phantoms representing two adult patient sizes were captured using a modern flat panel detector based x-ray imaging system. Tin and copper test details were used to simulate iodine-based contrast medium and stents/guide wires respectively, which are used in clinical procedures. Noise measurement for a flat field image and test detail contrast were used to calculate the contrast to noise ratio (CNR). Entrance surface dose (ESD) and effective dose measurements were obtained to calculate the figure of merit (FOM), CNR{sup 2}/dose. This FOM determined the dose efficiency of x-ray spectra investigated. Images were captured with 0.0, 0.1, 0.25, 0.4, and 0.9 mm Cu filtration and with a range of gadolinium oxysulphide (Gd{sub 2}O{sub 2}S) filtration.Results: Optimum x-ray spectra were the same for the tin and copper test details. Lower peak tube voltages were generally favored. For the 20 cm phantom, using 2 Lanex Fast Back Gd{sub 2}O{sub 2}S screens as x-ray filtration at 65 kVp provided the highest FOM considering ESD and effective dose. Considering ESD, this FOM was only marginally larger than that from using 0.4 mm Cu at 65 kVp. For the 30 cm phantom, using 0.25 mm copper filtration at 80 kVp was most optimal; considering effective dose the FOM was highest with no filtration at 65 kVp.Conclusions: These settings, adjusted for x-ray tube loading limits and clinically acceptable image quality, should provide a useful option for optimizing patient dose to image quality in cardiac x-ray imaging. The same optimal x-ray beam spectra were found for both the tin and copper details, suggesting that iodine contrast based imaging and visualization of interventional devices could potentially be optimized for dose using similar x-ray beam spectra.

  2. A Fast X-ray Disk Wind in the Transient Pulsar IGR J17480-2446 in Terzan 5

    E-Print Network [OSTI]

    Jon M. Miller; Dipankar Maitra; Edward M. Cackett; Sudip Bhattacharyya; Tod E. Strohmayer

    2011-02-28

    Accretion disk winds are revealed in Chandra gratings spectra of black holes. The winds are hot and highly ionized (typically composed of He-like and H-like charge states), and show modest blue-shifts. Similar line spectra are sometimes seen in "dipping" low-mass X-ray binaries, which are likely viewed edge-on; however, that absorption is tied to structures in the outer disk, and blue-shifts are not typically observed. Here we report the detection of blue-shifted He-like Fe XXV (3100 +/- 400 km/s) and H-like Fe XXVI (1000 +/- 200 km/s) absorption lines in a Chandra/HETG spectrum of the transient pulsar and low-mass X-ray binary IGR J17480-2446 in Terzan 5. These features indicate a disk wind with at least superficial similarities to those observed in stellar-mass black holes. The wind does not vary strongly with numerous weak X-ray bursts or flares. A broad Fe K emission line is detected in the spectrum, and fits with different line models suggest that the inner accretion disk in this system may be truncated. If the stellar magnetic field truncates the disk, a field strength of B = 0.7-4.0 E+9 Gauss is implied, which is in line with estimates based on X-ray timing techniques. We discuss our findings in the context of accretion flows onto neutron stars and stellar-mass black holes.

  3. Soft X-Ray Spectroscopic Study of Dense Strontium-Doped Lanthanum Manganite Cathodes for Solid Oxide Fuel Cell Applications

    SciTech Connect (OSTI)

    L Piper; A Preston; S Cho; A DeMasi; J Laverock; K Smith; L Miara; J Davis; S Basu; et al.

    2011-12-31

    The evolution of the Mn charge state, chemical composition, and electronic structure of La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSMO) cathodes during the catalytic activation of solid oxide fuel cell (SOFC) has been studies using X-ray spectroscopy of as-processed, exposed, and activated dense thin LSMO films. Comparison of O K-edge and Mn L{sub 3,2}-edge X-ray absorption spectra from the different stages of LSMO cathodes revealed that the largest change after the activation occurred in the Mn charge state with little change in the oxygen environment. Core-level X-ray photoemission spectroscopy and Mn L{sub 3} resonant photoemission spectroscopy studies of exposed and as-processed LSMO determined that the SOFC environment (800 C ambient pressure of O{sub 2}) alone results in La deficiency (severest near the surface with Sr doping >0.55) and a stronger Mn{sup 4+} contribution, leading to the increased insulating character of the cathode prior to activation. Meanwhile, O K-edge X-ray absorption measurements support Sr/La enrichment nearer the surface, along with the formation of mixed Sr{sub x}Mn{sub y}O{sub z} and/or passive MnO{sub x} and SrO species.

  4. X-ray tube with magnetic electron steering

    DOE Patents [OSTI]

    Reed, Kim W. (Albuquerque, NM); Turman, Bobby N. (Albuquerque, NM); Kaye, Ronald J. (Albuquerque, NM); Schneider, Larry X. (Albuquerque, NM)

    2000-01-01

    An X-ray tube uses a magnetic field to steer electrons. The magnetic field urges electrons toward the anode, increasing the proportion of electrons emitted from the cathode that reach desired portions of the anode and consequently contribute to X-ray production. The magnetic field also urges electrons reflected from the anode back to the anode, further increasing the efficiency of the tube.

  5. New Directions in X-Ray Light Sources

    ScienceCinema (OSTI)

    Falcone, Roger

    2010-01-08

    July 15, 2008 Berkeley Lab lecture: Molecular movies of chemical reactions and material phase transformations need a strobe of x-rays, the penetrating light that reveals how atoms and molecules assemble in chemical and biological systems and complex materials. Roger Falcone, Director of the Advanced Light Source,will discuss a new generation of x ray sources that will enable a new science of atomic dynamics on ultrafast timescales.

  6. New focusing multilayer structures for X-ray plasma spectroscopy

    SciTech Connect (OSTI)

    Bibishkin, M S; Luchin, V I; Salashchenko, N N; Chernov, V V; Chkhalo, N I; Kazakov, E D; Shevelko, A P

    2008-02-28

    New focusing short-period multilayer structures are developed which opens up wide possibilities for X-ray and VUV spectroscopy. Multilayer structures are deposited on a flat surface of a mica crystal which is then bent to a small-radius cylinder. The use of this structure in a von Hamos spectrometer for X-ray laser plasma diagnostics is demonstrated. (interaction of laser radiation with matter. laser plasma)

  7. A Remarkable Low-Mass X-ray Binary within 0.1 pc of the Galactic Center

    E-Print Network [OSTI]

    M. P. Muno; J. R. Lu; F. K. Baganoff; W. N. Brandt; G. P. Garmire; A. M. Ghez; S. D. Hornstein; M. R. Morris

    2005-03-26

    Recent X-ray and radio observations have identified a transient low-mass X-ray binary (LMXB) located only 0.1 pc in projection from the Galactic center, CXOGC J174540.0-290031. In this paper, we report the detailed analysis of X-ray and infrared observations of the transient and its surroundings. Chandra bservations detect the source at a flux of F_X = 2e-12 erg cm^-2 s^-1 (2-8 keV). After accounting for absorption both in the interstellar medium and in material local to the source, the implied luminosity of the source is only L_X = 4e34 erg/s (2-8 keV; D=8 kpc). However, the diffuse X-ray emission near the source also brightened by a factor of 2. The enhanced diffuse X-ray emission lies on top of a known ridge of dust and ionized gas that is visible infrared images. We interpret the X-ray emission as scattered flux from the outburst, and determine that the peak luminosity of CXOGC J174540.0-290031 was >2e36 erg/s. We suggest that the relatively small observed flux results from the fact that the system is observed nearly edge-on, so that the accretion disk intercepts most of the flux emitted along our line of sight. We compare the inferred peak X-ray luminosity to that of the radio jet. The ratio of the X-ray to radio luminosities, L_X/L_R 1e5). This is probably because the jets are radiating with unusually high efficiency at the point where they impact the surrounding interstellar medium. This hypothesis is supported by a comparison with mid-infrared images of the surrounding dust. Finally, we find that the minimum power required to produce the jet, L_jet~1e37 erg/s, is comparable to the inferred peak X-ray luminosity. This is the most direct evidence yet obtained that LMXBs accreting at low rates release about half of their energy as jets.

  8. MN Lup: X-RAYS FROM A WEAKLY ACCRETING T TAURI STAR

    SciTech Connect (OSTI)

    Guenther, H. M.; Wolk, S. J.; Wolter, U.; Robrade, J.

    2013-07-01

    Young T Tauri stars (TTS) are surrounded by an accretion disk, which over time disperses due to photoevaporation, accretion, and possibly planet formation. The accretion shock on the central star produces an UV/optical veiling continuum, line emission, and X-ray signatures. As the accretion rate decreases, the impact on the central star must change. In this article we study MN Lup, a young star where no indications of a disk are seen in IR observations. We present XMM-Newton and VLT/UVES observations, some of them taken simultaneously. The X-ray data show that MN Lup is an active star with L{sub X} /L{sub bol} close to the saturation limit. However, we find high densities (n{sub e} > 3 Multiplication-Sign 10{sup 10} cm{sup -3}) in the X-ray grating spectrum. This can be well fitted using an accretion shock model with an accretion rate of 2 Multiplication-Sign 10{sup -11} M{sub Sun} yr{sup -1}. Despite the simple H{alpha} line profile which has a broad component, but no absorption signatures as typically seen on accreting TTS, we find rotational modulation in Ca II K and in photospheric absorption lines. These line profile modulations do not clearly indicate the presence of a localized hot accretion spot on the star. In the H{alpha} line we see a prominence in absorption about 2R{sub *} above the stellar surface-the first of its kind on a TTS. MN Lup is also the only TTS where accretion is seen, but no dust disk is detected that could fuel it. We suggest that MN Lup presents a unique and short-lived state in the disk evolution. It may have lost its dust disk only recently and is now accreting the remaining gas at a very low rate.

  9. Evaluation of partial coherence correction in X-ray ptychography

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Burdet, Nicolas; Shi, Xiaowen; Parks, Daniel; Clark, Jesse N.; Huang, Xiaojing; Kevan, Stephen D.; Robinson, Ian K.

    2015-02-23

    Coherent X-ray Diffraction Imaging (CDI) and X-ray ptychography both heavily rely on the high degree of spatial coherence of the X-ray illumination for sufficient experimental data quality for reconstruction convergence. Nevertheless, the majority of the available synchrotron undulator sources have a limited degree of partial coherence, leading to reduced data quality and a lower speckle contrast in the coherent diffraction patterns. It is still an open question whether experimentalists should compromise the coherence properties of an X-ray source in exchange for a higher flux density at a sample, especially when some materials of scientific interest are relatively weak scatterers. Amore »previous study has suggested that in CDI, the best strategy for the study of strong phase objects is to maintain a high degree of coherence of the illuminating X-rays because of the broadening of solution space resulting from the strong phase structures. In this article, we demonstrate the first systematic analysis of the effectiveness of partial coherence correction in ptychography as a function of the coherence properties, degree of complexity of illumination (degree of phase diversity of the probe) and sample phase complexity. We have also performed analysis of how well ptychographic algorithms refine X-ray probe and complex coherence functions when those variables are unknown at the start of reconstructions, for noise-free simulated data, in the case of both real-valued and highly-complex objects.« less

  10. Spectral Formation in X-Ray Pulsar Accretion Columns

    E-Print Network [OSTI]

    Peter A. Becker; Michael T. Wolff

    2005-03-03

    We present the first self-consistent model for the dynamics and the radiative transfer occurring in bright X-ray pulsar accretion columns, with a special focus on the role of the shock in energizing the emerging X-rays. The pressure inside the accretion column of a luminous X-ray pulsar is dominated by the photons, and consequently the equations describing the coupled radiative-dynamical structure must be solved simultaneously. Spectral formation in these sources is therefore a complex, nonlinear phenomenon. We obtain the analytical solution for the Green's function describing the upscattering of monochromatic radiation injected into the column from the thermal mound located near the base of the flow. The Green's function is convolved with a Planck distribution to model the X-ray spectrum resulting from the reprocessing of blackbody photons produced in the thermal mound. These photons diffuse through the infalling gas and eventually escape out the walls of the column, forming the observed X-ray spectrum. We show that the resulting column-integrated, phase-averaged spectrum has a power-law shape at high energies and a blackbody shape at low energies, in agreement with the observational data for many X-ray pulsars.

  11. The ASTRO-H X-ray Observatory

    E-Print Network [OSTI]

    Takahashi, Tadayuki; Kelley, Richard; Aharonian, Henri AartsFelix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steve; Anabuki, Naohisa; Angelini, Lorella; Arnaud, Keith; Asai, Makoto; Audard, Marc; Awaki, Hisamitsu; Azzarello, Philipp; Baluta, Chris; Bamba, Aya; Bando, Nobutaka; Bautz, Mark; Blandford, Roger; Boyce, Kevin; Brown, Greg; Cackett, Ed; Chernyakova, Maria; Coppi, Paolo; Costantini, Elisa; de Plaa, Jelle; Herder, Jan-Willem den; DiPirro, Michael; Done, Chris; Dotani, Tadayasu; Doty, John; Ebisawa, Ken; Eckart, Megan; Enoto, Teruaki; Ezoe, Yuichiro; Fabian, Andrew; Ferrigno, Carlo; Foster, Adam; Fujimoto, Ryuichi; Fukazawa, Yasushi; Funk, Stefan; Furuzawa, Akihiro; Galeazzi, Massimiliano; Gallo, Luigi; Gandhi, Poshak; Gendreau, Keith; Gilmore, Kirk; Haas, Daniel; Haba, Yoshito; Hamaguchi, Kenji; Hatsukade, Isamu; Hayashi, Takayuki; Hayashida, Kiyoshi; Hiraga, Junko; Hirose, Kazuyuki; Hornschemeier, Ann; Hoshino, Akio; Hughes, John; Hwang, Una; Iizuka, Ryo; Inoue, Yoshiyuki; Ishibashi, Kazunori; Ishida, Manabu; Ishimura, Kosei; Ishisaki, Yoshitaka; Ito, Masayuki; Iwata, Naoko; Iyomoto, Naoko; Kaastra, Jelle; Kallman, Timothy; Kamae, Tuneyoshi; Kataoka, Jun; Katsuda, Satoru; Kawahara, Hajime; Kawaharada, Madoka; Kawai, Nobuyuki; Kawasaki, Shigeo; Khangaluyan, Dmitry; Kilbourne, Caroline; Kimura, Masashi; Kinugasa, Kenzo; Kitamoto, Shunji; Kitayama, Tetsu; Kohmura, Takayoshi; Kokubun, Motohide; Kosaka, Tatsuro; Koujelev, Alex; Koyama, Katsuji; Krimm, Hans; Kubota, Aya; Kunieda, Hideyo; LaMassa, Stephanie; Laurent, Philippe; Lebrun, Francois; Leutenegger, Maurice; Limousin, Olivier; Loewenstein, Michael; Long, Knox; Lumb, David; Madejski, Grzegorz; Maeda, Yoshitomo; Makishima, Kazuo; Marchand, Genevieve; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian; Miller, Jon; Miller, Eric; Mineshige, Shin; Minesugi, Kenji; Mitsuishi, Ikuyuki; Miyazawa, Takuya; Mizuno, Tsunefumi; Mori, Hideyuki; Mori, Koji; Mukai, Koji; Murakami, Toshio; Murakami, Hiroshi; Mushotzky, Richard; Nagano, Housei; Nagino, Ryo; Nakagawa, Takao; Nakajima, Hiroshi; Nakamori, Takeshi; Nakazawa, Kazuhiro; Namba, Yoshiharu; Natsukari, Chikara; Nishioka, Yusuke; Nobukawa, Masayoshi; Nomachi, Masaharu; Dell, Steve O'; Odaka, Hirokazu; Ogawa, Hiroyuki; Ogawa, Mina; Ogi, Keiji; Ohashi, Takaya; Ohno, Masanori; Ohta, Masayuki; Okajima, Takashi; Okamoto, Atsushi; Okazaki, Tsuyoshi; Ota, Naomi; Ozaki, Masanobu; Paerels, Frits; Paltani, Stephane; Parmar, Arvind; Petre, Robert; Pohl, Martin; Porter, F Scott; Ramsey, Brian; Reis, Rubens; Reynolds, Christopher; Russell, Helen; Safi-Harb, Samar; Sakai, Shin-ichiro; Sameshima, Hiroaki; Sanders, Jeremy; Sato, Goro; Sato, Rie; Sato, Yoichi; Sato, Kosuke; Sawada, Makoto; Serlemitsos, Peter; Seta, Hiromi; Shibano, Yasuko; Shida, Maki; Shimada, Takanobu; Shinozaki, Keisuke; Shirron, Peter; Simionescu, Aurora; Simmons, Cynthia; Smith, Randall; Sneiderman, Gary; Soong, Yang; Stawarz, Lukasz; Sugawara, Yasuharu; Sugita, Hiroyuki; Sugita, Satoshi; Szymkowiak, Andrew; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takeda, Shin-ichiro; Takei, Yoh; Tamagawa, Toru; Tamura, Takayuki; Tamura, Keisuke; Tanaka, Takaaki; Tanaka, Yasuo; Tashiro, Makoto; Tawara, Yuzuru; Terada, Yukikatsu; Terashima, Yuichi; Tombesi, Francesco; Tomida, Hiroshi; Tsuboi, Yoko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi; Uchida, Hiroyuki; Uchiyama, Yasunobu; Uchiyama, Hideki; Ueda, Yoshihiro; Ueno, Shiro; Uno, Shinichiro; Urry, Meg; Ursino, Eugenio; de Vries, Cor; Wada, Atsushi; Watanabe, Shin; Werner, Norbert; White, Nicholas; Yamada, Takahiro; Yamada, Shinya; Yamaguchi, Hiroya; Yamasaki, Noriko; Yamauchi, Shigeo; Yamauchi, Makoto; Yatsu, Yoichi; Yonetoku, Daisuke; Yoshida, Atsumasa; Yuasa, Takayuki

    2012-01-01

    The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit o...

  12. X-rays from protostellar jets: emission from continuous flows

    E-Print Network [OSTI]

    R. Bonito; S. Orlando; G. Peres; F. Favata; R. Rosner

    2006-10-17

    Recently X-ray emission from protostellar jets has been detected with both XMM-Newton and Chandra satellites, but the physical mechanism which can give rise to this emission is still unclear. We performed an extensive exploration of a wide space of the main parameters influencing the jet/ambient interaction. Aims include: 1) to constrain the jet/ambient interaction regimes leading to the X-ray emission observed in Herbig-Haro objects in terms of the emission by a shock forming at the interaction front between a continuous supersonic jet and the surrounding medium; 2) to derive detailed predictions to be compared with optical and X-ray observations of protostellar jets; 3) to get insight into the protostellar jet's physical conditions. We performed a set of bidimensional hydrodynamic numerical simulations, in cylindrical coordinates, modeling supersonic jets ramming a uniform ambient medium. The model takes into account the most relevant physical effects, namely the thermal conduction and the radiative losses. Our model explains the observed X-ray emission from protostellar jets in a natural way. In particular we find that the case of a protostellar jet less dense than the ambient medium reproduces well the observations of the nearest Herbig-Haro object, HH154, and allows us to make detailed predictions of a possible X-ray source proper motion (vsh = 500 km/s), detectable with Chandra. Furthermore our results suggest that the simulated protostellar jets which best reproduce the X-rays observations cannot drive molecular outflows.

  13. HIgh Rate X-ray Fluorescence Detector

    SciTech Connect (OSTI)

    Grudberg, Peter Matthew [XIA LLC

    2013-04-30

    The purpose of this project was to develop a compact, modular multi-channel x-ray detector with integrated electronics. This detector, based upon emerging silicon drift detector (SDD) technology, will be capable of high data rate operation superior to the current state of the art offered by high purity germanium (HPGe) detectors, without the need for liquid nitrogen. In addition, by integrating the processing electronics inside the detector housing, the detector performance will be much less affected by the typically noisy electrical environment of a synchrotron hutch, and will also be much more compact than current systems, which can include a detector involving a large LN2 dewar and multiple racks of electronics. The combined detector/processor system is designed to match or exceed the performance and features of currently available detector systems, at a lower cost and with more ease of use due to the small size of the detector. In addition, the detector system is designed to be modular, so a small system might just have one detector module, while a larger system can have many â?? you can start with one detector module, and add more as needs grow and budget allows. The modular nature also serves to simplify repair. In large part, we were successful in achieving our goals. We did develop a very high performance, large area multi-channel SDD detector, packaged with all associated electronics, which is easy to use and requires minimal external support (a simple power supply module and a closed-loop water cooling system). However, we did fall short of some of our stated goals. We had intended to base the detector on modular, large-area detectors from Ketek GmbH in Munich, Germany; however, these were not available in a suitable time frame for this project, so we worked instead with pnDetector GmbH (also located in Munich). They were able to provide a front-end detector module with six 100 m^2 SDD detectors (two monolithic arrays of three elements each) along with associated preamplifiers; these detectors surpassed the performance we expected to get from the Ketek detectors, however they are housed in a sealed module, which does not offer the ease of repair and expandability weâ??d hoped to achieve with the Ketek SDDâ??s. Our packaging efforts were quite successful, as we came up with a very compact way to mount the detector and to house the associated electronics, as well as a very effective way to reliably take out the heat (from the electronics as well as the detectorâ??s Peltier coolers) without risk of condensation and without external airflow or vibration, which could create problems for the target applications. While we were able to design compact processing electronics that fit into the detector assembly, they are still at the prototype stage, and would require a significant redesign to achieve product status. We have not yet tested this detector at a synchrotron facility; we do still plan on working with some close contacts at the nearby Stanford Synchrotron Radiation Laboratory (SSRL) to get some testing with the beam (using existing commercial electronics for readout, as the integrated processor is not ready for use).

  14. Water destruction by X-rays in young stellar objects

    E-Print Network [OSTI]

    P. Stauber; J. K. Jorgensen; E. F. van Dishoeck; S. D. Doty; A. O. Benz

    2006-02-06

    We study the H2O chemistry in star-forming environments under the influence of a central X-ray source and a central far ultraviolet (FUV) radiation field. The gas-phase water chemistry is modeled as a function of time, hydrogen density and X-ray flux. To cover a wide range of physical environments, densities between n_H = 10^4-10^9 cm^-3 and temperatures between T = 10-1000 K are studied. Three different regimes are found: For T water abundance is of order 10^-7-10^-6 and can be somewhat enhanced or reduced due to X-rays, depending on time and density. For 100 K 10^-3 ergs s-1 cm^-2 (t = 10^4 yrs) and for F_X > 10^-4 ergs s^-1 cm^-2 (t = 10^5 yrs). At higher temperatures (T > 250 K) and hydrogen densities, water can persist with x(H2O) ~ 10^-4 even for high X-ray fluxes. The X-ray and FUV models are applied to envelopes around low-mass Class 0 and I young stellar objects (YSOs). Water is destroyed in both Class 0 and I envelopes on relatively short timescales (t ~ 5000 yrs) for realistic X-ray fluxes, although the effect is less prominent in Class 0 envelopes due to the higher X-ray absorbing densities there. FUV photons from the central source are not effective in destroying water. The average water abundance in Class I sources for L_X > 10^27 ergs s^-1 is predicted to be x(H2O) < 10^-6.

  15. X-ray emitting young stars in the Orion Nebula

    E-Print Network [OSTI]

    Eric D. Feigelson; Patrick Broos; James A. Gaffney III; Gordon Garmire; Lynne A. Hillenbrand; Steven H. Pravdo; Leisa Townsley; Yohko Tsuboi

    2002-03-19

    The Orion Nebula Cluster and the molecular cloud in its vicinity have been observed with the ACIS-I detector on board the Chandra X-ray Observatory with 23 hours exposure. We detect 1075 X-ray sources: 91% are spatially associated with known stellar members of the cluster, and 7% are newly identified deeply embedded cloud members. This provides the largest X-ray study of a pre-main sequence stellar population. We examine here the X-ray properties of Orion young stars as a function of mass. Results include: (a) the discovery of rapid variability in the O9.5 31 M_o star \\theta^2A Ori, and several early B stars, inconsistent with the standard model of X-ray production in small wind shocks; (b) support for the hypothesis that intermediate-mass mid-B through A type stars do not themselves produce significant X-ray emission; (c) confirmation that low-mass G- through M-type T Tauri stars exhibit powerful flaring but typically at luminosities considerably below the `saturation' level; (d) confirmation that the presence or absence of a circumstellar disk has no discernable effect on X-ray emission; (e) evidence that T Tauri plasma temperatures are often very high with T >= 100 MK, even when luminosities are modest and flaring is not evident; and (f) detection of the largest sample of pre-main sequence very low mass objects showing high flaring levels and a decline in magnetic activity as they evolve into L- and T-type brown dwarfs.

  16. High-energy x-ray production with pyroelectric crystals Jeffrey A. Geuthera

    E-Print Network [OSTI]

    Danon, Yaron

    High-energy x-ray production with pyroelectric crystals Jeffrey A. Geuthera and Yaron Danon, the usefulness of an x-ray source is determined by its yield and endpoint energy. In x-ray fluorescence, for example, high-energy sources enable the excitation of the K-shell x-ray peaks for high-Z materials as well

  17. Tools for a Theoretical X-ray Beamline J. J. Rehr*

    E-Print Network [OSTI]

    Botti, Silvana

    Tools for a Theoretical X-ray Beamline J. J. Rehr* Department of Physics University of Washington, France 22 October 2010 #12;X-ray Spectroscopy Beamline #12;Tools for a Theoretical X-ray Beamline · GOAL Theoretical X-ray Beamline: 2. Tools for EXAFS and XANES, EELS, XMCD, ... 3. DFT/MD-TOOLS 4. Next generation

  18. Chemical Shifts in X-ray and Photo-Electron Spectroscopy: A Historical review

    E-Print Network [OSTI]

    Lindgren, Ingvar

    Chemical Shifts in X-ray and Photo-Electron Spectroscopy: A Historical review Ingvar Lindgren 1 Introduction 2 2 Chemical shift in X-ray spectroscopy 2 2.1 Discovery of the chemical shift in X-ray spectroscopy . . . . . . . . . . . . . 3 2.2 Interpretation of the chemical shift in X-ray spectroscopy

  19. Study of Interactions Between Microbes and Minerals by Scanning Transmission X-Ray Microscopy (STXM)

    E-Print Network [OSTI]

    Benzerara, K; Tyliszczak, T

    2007-01-01

    Study of Interactions Between Microbes and Minerals by Scanning Transmission X-Ray Microscopy (STXM)

  20. X-Ray Diagnostics for the Levitated Dipole Jennifer L. Ellsworth

    E-Print Network [OSTI]

    to utilize two x-ray diagnostics. An x-ray pulse height analyzer will measure the energy spectrum will be discussed. The x-ray pulse height analyzer and x-ray camera are vital to analyzing the first plasmas acquisition and electronics . . . . . . . . . . . . . . . . . 29 3.3.3 DXP4C2X Multichannel Analyzer Camac

  1. Scanning Transmission X-ray Microscopy: Applications in Atmospheric Aerosol Research

    E-Print Network [OSTI]

    Moffet, Ryan C.

    2011-01-01

    polymer photoresists by scanning transmission x-ray microscopy. Journal of Vacuum Science and Technology

  2. LOFT: the Large Observatory For X-ray Timing

    E-Print Network [OSTI]

    Belloni, Tomaso M

    2012-01-01

    LOFT, the large observatory for X-ray timing, is a new mission concept competing with other four candidates for a launch opportunity in 2022-2024. LOFT will be performing high-time resolution X-ray observations of compact objects, combining for the first time an unprecedented large collecting area for X-ray photons and a spectral resolution approaching that of CCD-based X-ray instruments (down to 200 eV FWHM at 6 keV). The operating energy range is 2-80 keV. The main science goals of LOFT are the measurement of the neutron stars equation of states and the test of General Relativity in the strong field regime. The breakthrough capabilities of the instruments on-board LOFT will permit to open also new discovery windows for a wide range of Galactic and extragalactic X-ray sources. In this contribution, we provide a general description of the mission concept and summarize its main scientific capabilities.

  3. The History of X-ray Free-Electron Lasers

    SciTech Connect (OSTI)

    Pellegrini, C.; ,

    2012-06-28

    The successful lasing at the SLAC National Accelerator Laboratory of the Linear Coherent Light Source (LCLS), the first X-ray free-electron laser (X-ray FEL), in the wavelength range 1.5 to 15 {angstrom}, pulse duration of 60 to few femtoseconds, number of coherent photons per pulse from 10{sup 13} to 10{sup 11}, is a landmark event in the development of coherent electromagnetic radiation sources. Until now electrons traversing an undulator magnet in a synchrotron radiation storage ring provided the best X-ray sources. The LCLS has set a new standard, with a peak X-ray brightness higher by ten orders of magnitudes and pulse duration shorter by three orders of magnitudes. LCLS opens a new window in the exploration of matter at the atomic and molecular scales of length and time. Taking a motion picture of chemical processes in a few femtoseconds or less, unraveling the structure and dynamics of complex molecular systems, like proteins, are some of the exciting experiments made possible by LCLS and the other X-ray FELs now being built in Europe and Asia. In this paper, we describe the history of the many theoretical, experimental and technological discoveries and innovations, starting from the 1960s and 1970s, leading to the development of LCLS.

  4. Viewing spin structures with soft x-ray microscopy

    SciTech Connect (OSTI)

    Fischer, Peter

    2010-06-01

    The spin of the electron and its associated magnetic moment marks the basic unit for magnetic properties of matter. Magnetism, in particular ferromagnetism and antiferromagnetism is described by a collective order of these spins, where the interaction between individual spins reflects a competition between exchange, anisotropy and dipolar energy terms. As a result the energetically favored ground state of a ferromagnetic system is a rather complex spin configuration, the magnetic domain structure. Magnetism is one of the eldest scientific phenomena, yet it is one of the most powerful and versatile utilized physical effects in modern technologies, such as in magnetic storage and sensor devices. To achieve highest storage density, the relevant length scales, such as the bit size in disk drives is now approaching the nanoscale and as such further developments have to deal with nanoscience phenomena. Advanced characterization tools are required to fully understand the underlying physical principles. Magnetic microscopes using polarized soft X-rays offer a close-up view into magnetism with unique features, these include elemental sensitivity due to X-ray magnetic dichroism effects as contrast mechanism, high spatial resolution provided by state-of-the-art X-ray optics and fast time resolution limited by the inherent time structure of current X-ray sources, which will be overcome with the introduction of ultrafast and high brilliant X-ray sources.

  5. Method and apparatus for micromachining using hard X-rays

    DOE Patents [OSTI]

    Siddons, D.P.; Johnson, E.D.; Guckel, H.; Klein, J.L.

    1997-10-21

    An X-ray source such as a synchrotron which provides a significant spectral content of hard X-rays is used to expose relatively thick photoresist such that the portions of the photoresist at an exit surface receive at least a threshold dose sufficient to render the photoresist susceptible to a developer, while the entrance surface of the photoresist receives an exposure which does not exceed a power limit at which destructive disruption of the photoresist would occur. The X-ray beam is spectrally shaped to substantially eliminate lower energy photons while allowing a substantial flux of higher energy photons to pass through to the photoresist target. Filters and the substrate of the X-ray mask may be used to spectrally shape the X-ray beam. Machining of photoresists such as polymethylmethacrylate to micron tolerances may be obtained to depths of several centimeters, and multiple targets may be exposed simultaneously. The photoresist target may be rotated and/or translated in the beam to form solids of rotation and other complex three-dimensional structures. 21 figs.

  6. Method and apparatus for micromachining using hard X-rays

    DOE Patents [OSTI]

    Siddons, David Peter (Shoreham, NY); Johnson, Erik D. (Ridge, NY); Guckel, Henry (Madison, WI); Klein, Jonathan L. (Madison, WI)

    1997-10-21

    An X-ray source such as a synchrotron which provides a significant spectral content of hard X-rays is used to expose relatively thick photoresist such that the portions of the photoresist at an exit surface receive at least a threshold dose sufficient to render the photoresist susceptible to a developer, while the entrance surface of the photoresist receives an exposure which does not exceed a power limit at which destructive disruption of the photoresist would occur. The X-ray beam is spectrally shaped to substantially eliminate lower energy photons while allowing a substantial flux of higher energy photons to pass through to the photoresist target. Filters and the substrate of the X-ray mask may be used to spectrally shape the X-ray beam. Machining of photoresists such as polymethylmethacrylate to micron tolerances may be obtained to depths of several centimeters, and multiple targets may be exposed simultaneously. The photoresist target may be rotated and/or translated in the beam to form solids of rotation and other complex three-dimensional structures.

  7. Correlated X-ray/Ultraviolet/Optical Variability in NGC 6814

    E-Print Network [OSTI]

    Troyer, Jon; Cackett, Edward; Bentz, Misty; Goad, Michael; Horne, Keith; Seals, James

    2015-01-01

    We present results of a 3-month combined X-ray/UV/optical monitoring campaign of the Seyfert 1 galaxy NGC 6814. The object was monitored by Swift from June through August 2012 in the X-ray and UV bands and by the Liverpool Telescope from May through July 2012 in B and V. The light curves are variable and significantly correlated between wavebands. Using cross-correlation analysis, we compute the time lag between the X-ray and lower energy bands. These lags are thought to be associated with the light travel time between the central X-ray emitting region and areas further out on the accretion disc. The computed lags support a thermal reprocessing scenario in which X-ray photons heat the disc and are reprocessed into lower energy photons. Additionally, we fit the lightcurves using CREAM, a Markov Chain Monte Carlo code for a standard disc. The best-fitting standard disc model yields unreasonably high super-Eddington accretion rates. Assuming more reasonable accretion rates would result in significantly under-pre...

  8. ON THE X-RAY OUTBURSTS OF TRANSIENT ANOMALOUS X-RAY PULSARS AND SOFT GAMMA-RAY REPEATERS

    SciTech Connect (OSTI)

    Cal Latin-Small-Letter-Dotless-I skan, Sirin; Ertan, Uenal [Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I -Tuzla, Istanbul, 34956 (Turkey)

    2012-10-20

    We show that the X-ray outburst light curves of four transient anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs), namely, XTE J1810-197, SGR 0501+4516, SGR 1627-41, and CXOU J164710.2-455216, can be produced by the fallback disk model that was also applied to the outburst light curves of persistent AXPs and SGRs in our earlier work. The model solves the diffusion equation for the relaxation of a disk that has been pushed back by a soft gamma-ray burst. The sets of main disk parameters used for these transient sources are very similar to each other and to those employed in our earlier models of persistent AXPs and SGRs. There is a characteristic difference between the X-ray outburst light curves of transient and persistent sources. This can be explained by the differences in the disk surface density profiles of the transient and persistent sources in quiescence indicated by their quiescent X-ray luminosities. Our results imply that a viscous disk instability operating at a critical temperature in the range of {approx}1300-2800 K is a common property of all fallback disks around AXPs and SGRs. The effect of the instability is more pronounced and starts earlier for the sources with lower quiescent luminosities, which leads to the observable differences in the X-ray enhancement light curves of transient and persistent sources. A single active disk model with the same basic disk parameters can account for the enhancement phases of both transient and persistent AXPs and SGRs. We also present a detailed parameter study to show the effects of disk parameters on the evolution of the X-ray luminosity of AXPs and SGRs in the X-ray enhancement phases.

  9. Chandra Multi-wavelength Project (ChaMP). II. First Results of X-ray Source Properties

    E-Print Network [OSTI]

    D. -W. Kim; B. J. Wilkes; P. J. Green; R. A. Cameron; J. J. Drake; N. R. Evans; P. Freeman; T. J. Gaetz; H. Ghosh; F. R. Harnden, Jr.; M. Karovska; V. Kashyap; P. W. Maksym; P. W. Ratzlaff; E. M. Schlegel; J. D. Silverman; H. D. Tananbaum; A. A. Vikhlinin

    2003-08-27

    We present the first results of ChaMP X-ray source properties obtained from the initial sample of 62 observations. The data have been uniformly reduced and analyzed with techniques specifically developed for the ChaMP and then validated by visual examination. Utilizing only near on-axis, bright X-ray sources (to avoid problems caused by incompleteness and the Eddington bias), we derive the Log(N)-Log(S) relation in soft (0.5-2 keV) and hard (2-8 keV) energy bands. The ChaMP data are consistent with previous results of ROSAT, ASCA and Chandra deep surveys. In particular, our data nicely fill in the flux gap in the hard band between the Chandra Deep Field data and the previous ASCA data. We check whether there is any systematic difference in the source density between cluster and non-cluster fields and also search for field-to-field variations, both of which have been previously reported. We found no significant field-to-field cosmic variation in either test within the statistics (~1 sigma) across the flux levels included in our sample. In the X-ray color-color plot, most sources fall in the location characterized by photon index = 1.5-2 and NH = a few x 10^20 cm^2, suggesting that they are typical broad-line AGNs. There also exist a considerable number of sources with peculiar X-ray colors (e.g., highly absorbed, very hard, very soft). We confirm a trend that on average the X-ray color hardens as the count rate decreases. Since the hardening is confined to the softest energy band (0.3-0.9 keV), we conclude it is most likely due to absorption. We cross-correlate the X-ray sources with other catalogs and describe their properties in terms of optical color, X-ray-to-optical luminosity ratio and X-ray colors.

  10. Double core-hole spectroscopy of transient plasmas produced in the interaction of ultraintense x-ray pulses with neon

    E-Print Network [OSTI]

    Gao, Cheng; Yuan, Jianmin

    2015-01-01

    Double core-hole (DCH) spectroscopy is investigated systematically for neon atomic system in the interaction with ultraintense x-ray pulses with photon energy from 937 eV to 2000 eV. A time-dependent rate equation, implemented in the detailed level accounting approximation, is utilized to study the dynamical evolution of the level population and emission properties of the highly transient plasmas. For x-ray pulses with photon energy in the range of 937-1030 eV, where $1s\\rightarrow 2p$ resonance absorption from single core-hole (SCH) states of neon charge states exist, inner-shell resonant absorption (IRA) effects play important roles in the time evolution of population and DCH spectroscopy. Such IRA physical effects are illustrated in detail by investigating the interaction of x-ray pulses at a photon energy of 944 eV, which corresponds to the $1s\\rightarrow 2p$ resonant absorption from the SCH states ($1s2s^22p^4$, $1s2s2p^5$ and $1s2p^6$) of Ne$^{3+}$. After averaging over the space and time distribution o...

  11. Hard X-rays from Emission Line Galaxies and the X-ray Background: A Test for Advection Dominated Accretion with Radio Sources

    E-Print Network [OSTI]

    Insu Yi; Stephen P. Boughn

    1997-10-14

    Recent studies of the cosmic X-ray background (XRB) have suggested the possible existence of a population of relatively faint sources with hard X-ray spectra; however, the emission mechanism remains unclear. If the hard X-ray emission is from the radiatively inefficient, advection dominated accretion flows (ADAFs) around massive black holes in galactic nuclei, X-ray luminosity and radio luminosity satisfy the approximate relation $L_R\\sim 7\\times 10^{35}(\

  12. Probing Final Stages of Stellar Evolution with X-Ray Observations of SN 2013ej

    E-Print Network [OSTI]

    Chakraborti, Sayan; Smith, Randall; Margutti, Raffaella; Pooley, David; Bose, Subhash; Sutaria, Firoza; Chandra, Poonam; Dwarkadas, Vikram V; Ryder, Stuart; Maeda, Keiichi

    2015-01-01

    Massive stars shape their surroundings with mass loss from winds during their lifetimes. Fast ejecta from supernovae, from these massive stars, shocks this circumstellar medium. Emission generated by this interaction provides a window into the final stages of stellar evolution, by probing the history of mass loss from the progenitor. Here we use Chandra and Swift x-ray observations of the type II-P/L SN 2013ej to probe the history of mass loss from its progenitor. We model the observed x-rays as emission from both heated circumstellar matter and supernova ejecta. The circumstellar density profile probed by the supernova shock reveals a history of steady mass loss during the final 400 years. The inferred mass loss rate of $2 \\times 10^{-6} {\\rm \\; M_\\odot \\; yr^{-1}}$ points back to a 13 $M_\\odot$ progenitor. Soon after the explosion we find significant absorption of reverse shock emission by a cooling shell. The column depth of this shell observed in absorption provides an independent and consistent measureme...

  13. X-ray Development of the Classical Nova V2672 Ophiuchi with Suzaku

    E-Print Network [OSTI]

    Takei, D; Drake, J J; Kitamoto, S

    2013-01-01

    We report the Suzaku detection of a rapid flare-like X-ray flux amplification early in the development of the classical nova V2672 Ophiuchi. Two target-of-opportunity ~25 ks X-ray observations were made 12 and 22 days after the outburst. The flux amplification was found in the latter half of day 12. Time-sliced spectra are characterized by a growing supersoft excess with edge-like structures and a relatively stable optically-thin thermal component with Ka emission lines from highly ionized Si. The observed spectral evolution is consistent with a model that has a time development of circumstellar absorption, for which we obtain the decline rate of ~10-40 % in a time scale of 0.2 d on day 12. Such a rapid drop of absorption and short-term flux variability on day 12 suggest inhomogeneous ejecta with dense blobs/holes in the line of sight. Then on day 22 the fluxes of both supersoft and thin-thermal plasma components become significantly fainter. Based on the serendipitous results we discuss the nature of this so...

  14. A seven-crystal Johann-type hard x-ray spectrometer at the Stanford Synchrotron Radiation Lightsource

    SciTech Connect (OSTI)

    Sokaras, D.; Weng, T.-C.; Nordlund, D.; Velikov, P.; Wenger, D.; Garachtchenko, A.; George, M.; Borzenets, V.; Johnson, B.; Rabedeau, T.; Alonso-Mori, R.; Bergmann, U.

    2013-05-15

    We present a multicrystal Johann-type hard x-ray spectrometer ({approx}5-18 keV) recently developed, installed, and operated at the Stanford Synchrotron Radiation Lightsource. The instrument is set at the wiggler beamline 6-2 equipped with two liquid nitrogen cooled monochromators - Si(111) and Si(311) - as well as collimating and focusing optics. The spectrometer consists of seven spherically bent crystal analyzers placed on intersecting vertical Rowland circles of 1 m of diameter. The spectrometer is scanned vertically capturing an extended backscattering Bragg angular range (88 Degree-Sign -74 Degree-Sign ) while maintaining all crystals on the Rowland circle trace. The instrument operates in atmospheric pressure by means of a helium bag and when all the seven crystals are used (100 mm of projected diameter each), has a solid angle of about 0.45% of 4{pi} sr. The typical resolving power is in the order of (E/{Delta}E){approx}10 000. The spectrometer's high detection efficiency combined with the beamline 6-2 characteristics permits routine studies of x-ray emission, high energy resolution fluorescence detected x-ray absorption and resonant inelastic x-ray scattering of very diluted samples as well as implementation of demanding in situ environments.

  15. X-ray emission from the double-binary OB-star system QZ Car (HD 93206)

    E-Print Network [OSTI]

    Parkin, E R; Townsley, L K; Pittard, J M; Moffat, A F J; Naze, Y; Rauw, G; Oskinova, L M

    2011-01-01

    X-ray observations of the double-binary OB-star system QZ Car (HD 93206) obtained with the Chandra X-ray Observatory over a period of roughly 2 years are presented. The orbit of systems A (O9.7 I+b2 v, PA = 21 d) and B (O8 III+o9 v, PB = 6 d) are reasonably well sampled by the observations, allowing the origin of the X-ray emission to be examined in detail. The X-ray spectra can be well fitted by an attenuated three temperature thermal plasma model, characterised by cool, moderate, and hot plasma components at kT ~ 0.2, 0.7, and 2 keV, respectively, and a circumstellar absorption of ~ 0.2 x 10^22 cm-2. Although the hot plasma component could be indicating the presence of wind-wind collision shocks in the system, the model fluxes calculated from spectral fits, with an average value of ~ 7 x 10^-13 erg s-1 cm-2, do not show a clear correlation with the orbits of the two constituent binaries. A semi-analytical model of QZ Car reveals that a stable momentum balance may not be established in either system A or B. ...

  16. X-ray emission from the giant magnetosphere of the magnetic O-type star NGC 1624-2

    E-Print Network [OSTI]

    Petit, V; Wade, G A; Nazé, Y; Owocki, S P; Sundqvist, J O; ud-Doula, A; Fullerton, A; Leutenegger, M; Gagné, M

    2015-01-01

    We observed NGC 1624-2, the O-type star with the largest known magnetic field Bp~20 kG), in X-rays with the ACIS-S camera onboard the Chandra X-ray Observatory. Our two observations were obtained at the minimum and maximum of the periodic Halpha emission cycle, corresponding to the rotational phases where the magnetic field is the closest to equator-on and pole-on, respectively. With these observations, we aim to characterise the star's magnetosphere via the X-ray emission produced by magnetically confined wind shocks. Our main findings are: (i) The observed spectrum of NGC 1624-2 is hard, similar to the magnetic O-type star Theta 1 Ori C, with only a few photons detected below 0.8 keV. The emergent X-ray flux is 30% lower at the Halpha minimum phase. (ii) Our modelling indicated that this seemingly hard spectrum is in fact a consequence of relatively soft intrinsic emission, similar to other magnetic Of?p stars, combined with a large amount of local absorption (~1-3 x 10^22 cm^-2). This combination is necess...

  17. Visualizing the non-equilibrium dynamics of photoinduced intramolecular electron transfer with femtosecond X-ray pulses

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Canton, Sophie E.; Kjær, Kasper S.; Vankó, György; van Driel, Tim B.; Adachi, Shin -ichi; Bordage, Amélie; Bressler, Christian; Chabera, Pavel; Christensen, Morten; Dohn, Asmus O.; et al

    2015-03-02

    Ultrafast photoinduced electron transfer preceding energy equilibration still poses many experimental and conceptual challenges to the optimization of photoconversion since an atomic-scale description has so far been beyond reach. Here we combine femtosecond transient optical absorption spectroscopy with ultrafast X-ray emission spectroscopy and diffuse X-ray scattering at the SACLA facility to track the non-equilibrated electronic and structural dynamics within a bimetallic donor–acceptor complex that contains an optically dark centre. Exploiting the 100-fold increase in temporal resolution as compared with storage ring facilities, these measurements constitute the first X-ray-based visualization of a non-equilibrated intramolecular electron transfer process over large interatomic distances.more »Thus experimental and theoretical results establish that mediation through electronically excited molecular states is a key mechanistic feature. The present study demonstrates the extensive potential of femtosecond X-ray techniques as diagnostics of non-adiabatic electron transfer processes in synthetic and biological systems, and some directions for future studies, are outlined.« less

  18. Archaeometrical studies using X-ray fluorescence methods

    SciTech Connect (OSTI)

    Pauna, Catalina; Constantinescu, B.; Constantin, F.; Bugoi, R.; Stan, D.; Vasilescu, A. [National Institute of Nuclear Physics and Engineering, POB MG-6, 077125, Bucharest (Romania)

    2010-04-26

    Elemental analysis contributes to authentication (knowing the elemental composition and considering the information about the usual composition of the objects in different historical periods it can be established if the item is original or fake), provenance studies (minor and trace elements indicates ores origin and 'consequently' mines location), (relative) dating of archaeological objects (e.g. for painted items--the chemical recipes for pigments can offer information about the age of objects). The paper gives a general layout for the NIPNE Archaeometry Laboratory's applications using X-Ray Fluorescence (XRF), micro--Proton Induced X-Ray Emission (micro-PIXE), micro-Synchrotron Radiation Induced X-Ray Fluorescence (micro--SR-XRF) methods.

  19. The Large Observatory For X-ray Timing: LOFT

    E-Print Network [OSTI]

    Bozzo, E

    2013-01-01

    LOFT, the Large Observatory for X-ray Timing, is a new space mission concept devoted to observations of Galactic and extra-Galactic sources in the X-ray domain with the main goals of probing gravity theory in the very strong field environment of black holes and other compact objects, and investigating the state of matter at supra-nuclear densities in neutron stars. The instruments on-board LOFT, the Large area detector and the Wide Field Monitor combine for the first time an unprecedented large effective area (~10 m2 at 8 keV) sensitive to X-ray photons mainly in the 2-30 keV energy range and a spectral resolution approaching that of CCD-based telescopes (down to 200 eV at 6 keV). LOFT is currently competing for a launch of opportunity in 2022 together with the other M3 mission candidates of the ESA Cosmic Vision Program.

  20. Non-thermal X-ray Emission from Supernova Remnants

    E-Print Network [OSTI]

    Jacco Vink

    2004-09-21

    Recent studies of narrow, X-ray synchrotron radiating filaments surrounding young supernova remnants indicate that magnetic fields strengths are relatively high, B ~ 0.1 mG, or even higher, and that diffusion is close to the Bohm limit. I illustrate this using Cas A as an example. Also older remnants such as RCW 86 appear to emit X-ray synchrotron radiation, but the emission is more diffuse, and not always confined to a region close to the shock front. I argue that for RCW 86 the magnetic field is likely to be low (B ~ 17 microGauss), and at the location where the shell emits X-ray synchrotron radiation the shock velocity is much higher than the average shock velocity of ~600 km/s.

  1. Imaging X-ray Thomson Scattering Spectrometer Design and Demonstration

    SciTech Connect (OSTI)

    Gamboa, E.J.; Huntington, C.M.; Trantham, M.R.; Keiter, P.A; Drake, R.P.; Montgomery, David; Benage, John F.; Letzring, Samuel A.

    2012-05-04

    In many laboratory astrophysics experiments, intense laser irradiation creates novel material conditions with large, one-dimensional gradients in the temperature, density, and ionization state. X-ray Thomson scattering is a powerful technique for measuring these plasma parameters. However, the scattered signal has previously been measured with little or no spatial resolution, which limits the ability to diagnose inhomogeneous plasmas. We report on the development of a new imaging x-ray Thomson spectrometer (IXTS) for the Omega laser facility. The diffraction of x-rays from a toroidally-curved crystal creates high-resolution images that are spatially resolved along a one-dimensional profile while spectrally dispersing the radiation. This focusing geometry allows for high brightness while localizing noise sources and improving the linearity of the dispersion. Preliminary results are presented from a scattering experiment that used the IXTS to measure the temperature profile of a shocked carbon foam.

  2. X-ray radiography with highly charged ions

    DOE Patents [OSTI]

    Marrs, Roscoe E. (Livermore, CA)

    2000-01-01

    An extremely small (1-250 micron FWHM) beam of slow highly charged ions deexciting on an x-ray production target generates x-ray monochromatic radiation that is passed through a specimen and detected for imaging. The resolution of the x-ray radiograms is improved and such detection is achieved with relatively low dosages of radiation passing through the specimen. An apparatus containing an electron beam ion trap (and modifications thereof) equipped with a focusing column serves as a source of ions that generate radiation projected onto an image detector. Electronic and other detectors are able to detect an increased amount of radiation per pixel than achieved by previous methods and apparati.

  3. Quiescent X-ray emission from an evolved brown dwarf ?

    E-Print Network [OSTI]

    B. Stelzer

    2004-09-27

    I report on the X-ray detection of Gl569Bab. During a 25ksec Chandra observation the binary brown dwarf is for the first time spatially separated in X-rays from the flare star primary Gl569A. Companionship to Gl569A constrains the age of the brown dwarf pair to ~300-800 Myr. The observation presented here is only the second X-ray detection of an evolved brown dwarf. About half of the observing time is dominated by a large flare on Gl569Bab, the remainder is characterized by weak and non-variable emission just above the detection limit. This emission -- if not related to the afterglow of the flare -- represents the first detection of a quiescent corona on a brown dwarf, representing an important piece in the puzzle of dynamos in the sub-stellar regime.

  4. Application of a PWFA to an X-ray FEL

    E-Print Network [OSTI]

    Israeli, Yasmine; Reiche, Sven; Pedrozzi, Marco; Muggli, Patric

    2016-01-01

    There is a growing demand for X-ray Free-electron lasers (FELs) in various science fields, in particular for those with short pulses, larger photon fluxes and shorter wavelengths. The level of X-ray power and the pulse energy depend on the amount of electron bunch energy. Increasing the latter will increase the power of the radiating X-rays. Using numerical simulations we explore the possibility of using a plasma wakefield accelerator (PWFA) scheme to increase the electron beam energy of an existing FEL facility without significantly increasing the accelerator length. In this paper we use parameters of the SwissFEL beam. The simulations are carried out in 2D cylindrical symmetry using the code OSIRIS. Initial results show an energy gain of ~2 GeV after propagation of 0.5 m in the plasma with a relative energy spread of ~1%.

  5. Data fusion in neutron and X-ray computed tomography

    SciTech Connect (OSTI)

    Schrapp, Michael J.; Goldammer, Matthias; Schulz, Michael; Issani, Siraj; Bhamidipati, Suryanarayana; Böni, Peter

    2014-10-28

    We present a fusion methodology between neutron and X-ray computed tomography (CT). On the one hand, the inspection by X-ray CT of a wide class of multimaterials in non-destructive testing applications suffers from limited information of object features. On the other hand, neutron imaging can provide complementary data in such a way that the combination of both data sets fully characterizes the object. In this contribution, a novel data fusion procedure, called Fusion Regularized Simultaneous Algebraic Reconstruction Technique, is developed where the X-ray reconstruction is modified to fulfill the available data from the imaging with neutrons. The experiments, which were obtained from an aluminum profile containing a steel screw, and attached carbon fiber plates demonstrate that the image quality in CT can be significantly improved when the proposed fusion method is used.

  6. Lensless x-ray imaging in reflection geometry

    SciTech Connect (OSTI)

    Roy, S.; Parks, D.H.; Seu, K.A.; Turner, J.J.; Chao, W.; Anderson, E.H.; Cabrini, S.; Kevan, S.D.; Su, R.

    2011-02-03

    Lensless X-ray imaging techniques such as coherent diffraction imaging and ptychography, and Fourier transform holography can provide time-resolved, diffraction-limited images. Nearly all examples of these techniques have focused on transmission geometry, restricting the samples and reciprocal spaces that can be investigated. We report a lensless X-ray technique developed for imaging in Bragg and small-angle scattering geometries, which may also find application in transmission geometries. We demonstrate this by imaging a nanofabricated pseudorandom binary structure in small-angle reflection geometry. The technique can be used with extended objects, places no restriction on sample size, and requires no additional sample masking. The realization of X-ray lensless imaging in reflection geometry opens up the possibility of single-shot imaging of surfaces in thin films, buried interfaces in magnetic multilayers, organic photovoltaic and field-effect transistor devices, or Bragg planes in a single crystal.

  7. Biological imaging by soft x-ray diffraction microscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shapiro, D.; Thibault, P.; Beetz, T.; Elser, V.; Howells, M.; Jacobsen, C.; Kirz, J.; Lima, E.; Miao, H.; Neiman, A. M.; et al

    2005-10-25

    We have used the method of x-ray diffraction microscopy to image the complex-valued exit wave of an intact and unstained yeast cell. The images of the freeze-dried cell, obtained by using 750-eV x-rays from different angular orientations, portray several of the cell's major internal components to 30-nm resolution. The good agreement among the independently recovered structures demonstrates the accuracy of the imaging technique. To obtain the best possible reconstructions, we have implemented procedures for handling noisy and incomplete diffraction data, and we propose a method for determining the reconstructed resolution. This work represents a previously uncharacterized application of x-ray diffractionmore »microscopy to a specimen of this complexity and provides confidence in the feasibility of the ultimate goal of imaging biological specimens at 10-nm resolution in three dimensions.« less

  8. The X-ray Telescope of the CAST Experiment

    E-Print Network [OSTI]

    R. Kotthaus; H. Braeuninger; P. Friedrich; R. Hartmann; D. Kang; M. Kuster; G. Lutz; L. Strueder

    2005-11-14

    The CERN Axion Solar Telescope (CAST) searches for solar axions employing a 9 Tesla superconducting dipole magnet equipped with 3 independent detection systems for X-rays from axion-photon conversions inside the 10 m long magnetic field. Results of the first 6 months of data taking in 2003 imply a 95 % CL upper limit on the axion-photon coupling constant of 1.16x10(-10) GeV(-1) for axion masses CAST is a X-ray telescope consisting of a Wolter I type mirror system and a fully depleted pn-CCD as focal plane detector. Exploiting the full potential of background suppression by focussing X-rays emerging from the magnet bore, the axion sensitivity obtained with telescope data taken in 2004, for the first time in a controlled laboratory experiment, will supersede axion constraints derived from stellar energy loss arguments.

  9. X-ray vs. water maser emission in AGN

    E-Print Network [OSTI]

    Castangia, P; Kadler, M; Henkel, C; Greenhill, L; Tueller, J

    2009-01-01

    Correlations between X-ray and water maser emission in AGN have been recently reported. However, the lack of systematic studies affects the confidence level of these results. In the following, we introduce a project aimed at studying all the water maser sources believed to be associated with AGN activity through X-ray data obtained with the XRT and BAT instruments on-board the Swift satellite. Preliminary results of this work indicate a promising rate of XRT detections allowing us to refine follow-up observing strategies focused on investigating the nuclei of individual galaxies and deriving, on statistical basis, the main characteristics of water maser hosts. In addition, a cross-correlation between our sample and the BAT 22-months all-sky survey provides an exceptionally high detection rate at hard X-ray energies when compared to other AGN-related catalogs.

  10. Movable anode x-ray source with enhanced anode cooling

    DOE Patents [OSTI]

    Bird, C.R.; Rockett, P.D.

    1987-08-04

    An x-ray source is disclosed having a cathode and a disc-shaped anode with a peripheral surface at constant radius from the anode axis opposed to the cathode. The anode has stub axle sections rotatably carried in heat conducting bearing plates which are mounted by thermoelectric coolers to bellows which normally bias the bearing plates to a retracted position spaced from opposing anode side faces. The bellows cooperate with the x-ray source mounting structure for forming closed passages for heat transport fluid. Flow of such fluid under pressure expands the bellows and brings the bearing plates into heat conducting contact with the anode side faces. A worm gear is mounted on a shaft and engages serrations in the anode periphery for rotating the anode when flow of coolant is terminated between x-ray emission events. 5 figs.

  11. Movable anode x-ray source with enhanced anode cooling

    DOE Patents [OSTI]

    Bird, Charles R. (Ypsilanti, MI); Rockett, Paul D. (Ann Arbor, MI)

    1987-01-01

    An x-ray source having a cathode and a disc-shaped anode with a peripheral surface at constant radius from the anode axis opposed to the cathode. The anode has stub axle sections rotatably carried in heat conducting bearing plates which are mounted by thermoelectric coolers to bellows which normally bias the bearing plates to a retracted position spaced from opposing anode side faces. The bellows cooperate with the x-ray source mounting structure for forming closed passages for heat transport fluid. Flow of such fluid under pressure expands the bellows and brings the bearing plates into heat conducting contact with the anode side faces. A worm gear is mounted on a shaft and engages serrations in the anode periphery for rotating the anode when flow of coolant is terminated between x-ray emission events.

  12. High efficiency of soft X-ray radiation reprocessing in supersoft X-ray sources due to multiple scattering

    E-Print Network [OSTI]

    V. Suleimanov; F. Meyer; E. Meyer-Hofmeister

    2003-02-19

    Detailed analysis of the lightcurve of CAL 87 clearly has shown that the high optical luminosity comes from the accretion disc rim and can only be explained by a severe thickening of the disc rim near the location where the accretion stream impinges. This area is irradiated by the X-rays where it faces the white dwarf. Only if the reprocessing rate of X-rays to optical light is high a luminosity as high as observed can be understood. But a recent detailed study of the soft X-ray radiation reprocessing in supersoft X-ray sources has shown that the efficiency is not high enough. We here propose a solution for this problem. As already discussed in the earlier lightcurve analysis the impact of the accretion stream at the outer disc rim produces a ``spray'', consisting of a large number of individual gas blobs imbedded in a surrounding corona. For the high mass flow rate this constitutes an optically thick vertically extended screen at the rim of the accretion disc. We analyse the optical properties of this irradiated spray and find that the multiple scattering between these gas blobs leads to an effective reprocessing of soft X-rays to optical light as required by the observations.

  13. High-resolution X-ray spectroscopy of Theta Car

    E-Print Network [OSTI]

    Yael Naze; Gregor Rauw

    2008-08-25

    Context : The peculiar hot star Theta Car in the open cluster IC2602 is a blue straggler as well as a single-line binary of short period (2.2d). Aims : Its high-energy properties are not well known, though X-rays can provide useful constraints on the energetic processes at work in binaries as well as in peculiar, single objects. Methods : We present the analysis of a 50ks exposure taken with the XMM-Newton observatory. It provides medium as well as high-resolution spectroscopy. Results : Our high-resolution spectroscopy analysis reveals a very soft spectrum with multiple temperature components (1--6MK) and an X-ray flux slightly below the `canonical' value (log[L_X(0.1-10.)/L_{BOL}] ~ -7). The X-ray lines appear surprisingly narrow and unshifted, reminiscent of those of beta Cru and tau Sco. Their relative intensities confirm the anomalous abundances detected in the optical domain (C strongly depleted, N strongly enriched, O slightly depleted). In addition, the X-ray data favor a slight depletion in neon and iron, but they are less conclusive for the magnesium abundance (solar-like?). While no significant changes occur during the XMM-Newton observation, variability in the X-ray domain is detected on the long-term range. The formation radius of the X-ray emission is loosely constrained to <5 R_sol, which allows for a range of models (wind-shock, corona, magnetic confinement,...) though not all of them can be reconciled with the softness of the spectrum and the narrowness of the lines.

  14. Concave Accretion Discs and X-ray Reprocessing

    E-Print Network [OSTI]

    Eric G. Blackman

    1999-03-16

    Spectra of Seyfert Is are commonly modelled as emission from an X-ray illuminated flat accretion disc orbiting a central black hole. This provides both a reprocessed and direct component of the X-ray emission as required by observations of individual objects and possibly a fraction of the cosmological X-ray background. There is some observational motivation to at least consider the role that an effectively concave disc surface might play: (1) a reprocessed fraction $\\gsim 1/2$ in some Seyferts and possibly in the X-ray background, and (2) the commonality of a sharp iron line peak for Seyferts at 6.4KeV despite a dependence of peak location on inclination angle for flat disc models. Here it is shown that a concave disc may not only provide a larger total fraction of reprocessed photons, but can also reprocess a much larger fraction of photons in its outer regions when compared to a flat disc. This reduces the sensitivity of the 6.4KeV peak location to the inner disc inclination angle because the outer regions are less affected by Doppler and gravitational effects. If the X-ray source is isotropic, the reprocessed fraction is directly determined by the concavity. If the X-ray source is anisotropic, the location of iron line peak can still be determined by concavity but the total reflected fraction need not be as large as for the isotropic emitter case. The geometric calculations herein are applicable to general accretion disc systems illuminated from the center.

  15. Serial femtosecond X-ray diffraction of enveloped virus microcrystals

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lawrence, Robert M.; Conrad, Chelsie E.; Zatsepin, Nadia A.; Grant, Thomas D.; Liu, Haiguang; James, Daniel; Nelson, Garrett; Subramanian, Ganesh; Aquila, Andrew; Hunter, Mark S.; et al

    2015-08-20

    Serial femtosecond crystallography (SFX) using X-ray free-electron lasers has produced high-resolution, room temperature, time-resolved protein structures. We report preliminary SFX of Sindbis virus, an enveloped icosahedral RNA virus with ~700 Å diameter. Microcrystals delivered in viscous agarose medium diffracted to ~40 Å resolution. Small-angle diffuse X-ray scattering overlaid Bragg peaks and analysis suggests this results from molecular transforms of individual particles. Viral proteins undergo structural changes during entry and infection, which could, in principle, be studied with SFX. This is a pertinent step toward determining room temperature structures from virus microcrystals that may enable time-resolved studies of enveloped viruses.

  16. Confusion of Diffuse Objects in the X-ray Sky

    E-Print Network [OSTI]

    G. Mark Voit; August E. Evrard; Greg L. Bryan

    2000-12-08

    Most of the baryons in the present-day universe are thought to reside in intergalactic space at temperatures of 10^5-10^7 K. X-ray emission from these baryons contributes a modest (~10%) fraction of the ~ 1 keV background whose prominence within the large-scale cosmic web depends on the amount of non-gravitational energy injected into intergalactic space by supernovae and AGNs. Here we show that the virialized regions of groups and clusters cover over a third of the sky, creating a source-confusion problem that may hinder X-ray searches for individual intercluster filaments and contaminate observations of distant groups.

  17. Cooled window for X-rays or charged particles

    DOE Patents [OSTI]

    Logan, C.M.

    1996-04-16

    A window is disclosed that provides good structural integrity and a very high capacity for removal of the heat deposited by x-rays, electrons, or ions, with minimum attenuation of the desired beam. The window is cooled by providing microchannels therein through which a coolant is pumped. For example, the window may be made of silicon with etched microchannels therein and covered by a silicon member. A window made of silicon with a total thickness of 520 {micro}m transmits 96% of the x-rays at an energy of 60 keV, and the transmission is higher than 90% for higher energy photons. 1 fig.

  18. Cooled window for X-rays or charged particles

    DOE Patents [OSTI]

    Logan, Clinton M. (Pleasanton, CA)

    1996-01-01

    A window that provides good structural integrity and a very high capacity for removal of the heat deposited by x-rays, electrons, or ions, with minimum attenuation of the desired beam. The window is cooled by providing microchannels therein through which a coolant is pumped. For example, the window may be made of silicon with etched microchannels therein and covered by a silicon member. A window made of silicon with a total thickness of 520 .mu.m transmits 96% of the x-rays at an energy of 60 keV, and the transmission is higher than 90% for higher energy photons.

  19. A 0535+26: an X-ray/Optical Tour

    E-Print Network [OSTI]

    Camero-Arranz, A; Wilson-Hodge, C A; Jenke, P; Coe, M J; Steele, I; Caballero, I; Gutierrez-Soto, J; Kretschmar, P; Suso, J; McBride, V A; Rodriguez, J

    2011-01-01

    We compiled X-ray and Optical observations of the accreting X-ray binary system A 0535+262 since its discovery in 1975, that will allow us to shed light on the unpredictable behavior of this binary system. We present the data in terms of the Be-disk interaction with the neutron star companion. In addition, we show recent results from the continuous monitoring of this source by the Gamma-ray Burst Monitor(GBM), on board the Fermi observatory, since its launch in 2008 June 11.

  20. Bragg x-ray survey spectrometer for ITER

    SciTech Connect (OSTI)

    Varshney, S. K.; Jakhar, S. [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India); Barnsley, R. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); O'Mullane, M. G. [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2012-10-15

    Several potential impurity ions in the ITER plasmas will lead to loss of confined energy through line and continuum emission. For real time monitoring of impurities, a seven channel Bragg x-ray spectrometer (XRCS survey) is considered. This paper presents design and analysis of the spectrometer, including x-ray tracing by the Shadow-XOP code, sensitivity calculations for reference H-mode plasma and neutronics assessment. The XRCS survey performance analysis shows that the ITER measurement requirements of impurity monitoring in 10 ms integration time at the minimum levels for low-Z to high-Z impurity ions can largely be met.

  1. High resolution collimator system for X-ray detector

    DOE Patents [OSTI]

    Eberhard, Jeffrey W. (Schenectady, NY); Cain, Dallas E. (Scotia, NY)

    1987-01-01

    High resolution in an X-ray computerized tomography (CT) inspection system is achieved by using a collimator/detector combination to limit the beam width of the X-ray beam incident on a detector element to the desired resolution width. In a detector such as a high pressure Xenon detector array, a narrow tapered collimator is provided above a wide detector element. The collimator slits have any desired width, as small as a few mils at the top, the slit width is easily controlled, and they are fabricated on standard machines. The slit length determines the slice thickness of the CT image.

  2. The First Angstrom X-Ray Free-Electron Laser

    SciTech Connect (OSTI)

    Galayda, John; /SLAC

    2012-08-24

    The Linac Coherent Light Source produced its first x-ray laser beam on 10 April 2009. Today it is routinely producing x-ray pulses with energy >2 mJ across the operating range from 820-8,200 eV. The facility has begun operating for atomic/molecular/optical science experiments. Performance of the facility in its first user run (1 October - 21 December) and current machine development activities will be presented. Early results from the preparations for the start of the second user run is also reported.

  3. X-Ray Diffraction Microscopy of Magnetic Structures

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWind Power >X-RayX-Ray

  4. X-Ray Microscopy Capabilities | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWindX-Ray Imaging of theX-Ray

  5. X-Ray Microscopy and Imaging: Science and Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWindX-Ray ImagingIn the X-ray

  6. SWIFT AND XMM-NEWTON OBSERVATIONS OF THE EXTRAORDINARY GAMMA-RAY BURST 060729: MORE THAN 125 DAYS OF X-RAY AFTERGLOW

    E-Print Network [OSTI]

    Zhang, Bing

    SWIFT AND XMM-NEWTON OBSERVATIONS OF THE EXTRAORDINARY GAMMA-RAY BURST 060729: MORE THAN 125 DAYS:1 and absorption column density of 1 ; 1021 cmÃ?2 . Subject headinggs: gamma rays: bursts -- X-rays: bursts Online material: color figure 1. INTRODUCTION Gamma-ray bursts (GRBs) are the most powerful explosions

  7. An SZ/X-ray galaxy cluster model and the X-ray follow-up of the Planck clusters

    E-Print Network [OSTI]

    A. Chamballu; J. G. Bartlett; J. -B. Melin; M. Arnaud

    2008-05-28

    Sunyaev-Zel'dovich (SZ) cluster surveys will become an important cosmological tool over next few years, and it will be essential to relate these new surveys to cluster surveys in other wavebands. We present an empirical model of cluster SZ and X-ray observables constructed to address this question and to motivate, dimension and guide X-ray follow-up of SZ surveys. As an example application of the model, we discuss potential XMM-Newton follow-up of Planck clusters.

  8. A mirror for lab-based quasi-monochromatic parallel x-rays

    SciTech Connect (OSTI)

    Nguyen, Thanhhai; Lu, Xun; Lee, Chang Jun; Jeon, Insu; Jung, Jin-Ho; Jin, Gye-Hwan; Kim, Sung Youb

    2014-09-15

    A multilayered parabolic mirror with six W/Al bilayers was designed and fabricated to generate monochromatic parallel x-rays using a lab-based x-ray source. Using this mirror, curved bright bands were obtained in x-ray images as reflected x-rays. The parallelism of the reflected x-rays was investigated using the shape of the bands. The intensity and monochromatic characteristics of the reflected x-rays were evaluated through measurements of the x-ray spectra in the band. High intensity, nearly monochromatic, and parallel x-rays, which can be used for high resolution x-ray microscopes and local radiation therapy systems, were obtained.

  9. Enhanced Electron Efficiency in an X-ray Diode

    SciTech Connect (OSTI)

    K. Sun, L. MacNeil

    2010-05-20

    The goal for this research is to optimize the XRD structure and usage configurations and increase the efficiency of the XRD. This research was successful in optimizing the XRD structure and usage configurations, thus creating a high efficiency XRD. Best efficiency occurs when there is an angle between the photocathode and incident X-rays.

  10. DEDUCING ELECTRON PROPERTIES FROM HARD X-RAY OBSERVATIONS

    E-Print Network [OSTI]

    Piana, Michele

    , University of New Hampshire, Durham, NH 03824, U.S.A. 9 Dipartimento di Informatica, Universit`a di Verona-ray polarization measurements have imposed significant new constraints on the degree of anisotropy distribution 42 5.5 X-ray polarization and electr

  11. Lensless imaging of nanoporous glass with soft X-rays

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Turner, Joshua J.; Nelson, Johanna; Huang, Xiaojing; Steinbrener, Jan; Jacobsen, Chris

    2013-06-01

    Coherent soft X-ray diffraction has been used to image nanoporous glass structure in two dimensions using different methods. The merit of the reconstructions was judged using a new method of Fourier phase correlation with a final, refined image. The porous structure was found to have a much larger average size then previously believed.

  12. STRUCTURAL VIROLOGY X-ray crystal structures of native

    E-Print Network [OSTI]

    Napp, Nils

    STRUCTURAL VIROLOGY X-ray crystal structures of native HIV-1 capsid protein reveal conformational) hexamers that shield the viral genome and proteins have been elusive. We report crystal structures-binding site. Inherent structural plasticity, hydration layer rearrangement, and effector binding affect capsid

  13. X-ray Emission from Thunderstorms and Lightning

    ScienceCinema (OSTI)

    Dwyer, Joseph [Florida Institute of Technology, Melbourne, Florida, United States

    2010-01-08

    How lightning is initiated in the relatively low electric fields inside thunderclouds and how it can then propagate for tens of kilometers through virgin air are two of the great unsolved problems in the atmospheric sciences.  Until very recently it was believed that lightning was entirely a conventional discharge, involving only low-energy (a few eV) electrons.  This picture changed completely a few years ago with the discovery of intense x-ray emission from both natural cloud-to-ground lightning and rocket-triggered lightning.  This energetic emission cannot be produced by a conventional discharge, and so the presence of x-rays strongly implies that runaway breakdown plays a role in lightning processes.  During runaway breakdown, electrons are accelerated through air to nearly the speed of light by strong electric fields.  These runaway electrons then emit bremsstrahlung x-rays and gamma-rays during collisions with air.  Indeed, the x-ray and gamma-ray emission produced by runaway breakdown near the tops of thunderstorms is bright enough to be seen from outer space, 600 km away.  As a result, the physics used for decades to describe thunderstorm electrification and lightning discharges is incomplete and needs to be revisited. 

  14. Generating coherent broadband continuum soft-x-ray radiation by

    E-Print Network [OSTI]

    Neumark, Daniel M.

    Generating coherent broadband continuum soft-x-ray radiation by attosecond ionization gating Thomas as the driver for high-harmonic generation that has a cosine-like electric field stabilized with respect the generation of broadband and tunable attosecond pulses. Instead of fixing the carrier-envelope phase

  15. Vanadium-pumped titanium x-ray laser

    DOE Patents [OSTI]

    Nilsen, Joseph (Livermore, CA)

    1992-01-01

    A resonantly photo-pumped x-ray laser (10) is formed of a vanadium (12) and titanium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state neon-like titanium ions (34) are resonantly photo-pumped by line emission from fluorine-like vanadium ions (32).

  16. Vanadium-pumped titanium x-ray laser

    DOE Patents [OSTI]

    Nilsen, J.

    1992-05-26

    A resonantly photo-pumped x-ray laser is formed of a vanadium and titanium foil combination that is driven by two beams of intense line focused optical laser radiation. Ground state neon-like titanium ions are resonantly photo-pumped by line emission from fluorine-like vanadium ions. 4 figs.

  17. Soft x-ray diagnostics for pulsed power machines

    SciTech Connect (OSTI)

    Idzorek, G.C.; Coulter, W.L.; Walsh, P.J.; Montoya, R.R.

    1995-08-01

    A variety of soft x-ray diagnostics are being fielded on the Los Alamos National Laboratory Pegasus and Procyon pulsed power systems and also being fielded on joint US/Russian magnetized target fusion experiments known as MAGO (Magnitoye Obzhatiye). The authors have designed a low-cost modular photoemissive detector designated the XRD-96 that uses commercial 1100 series aluminum for the photocathode. In addition to photocathode detectors a number of designs using solid state silicon photodiodes have been designed and fielded. They also present a soft x-ray time-integrated pinhole camera system that uses standard type TMAX-400 photographic film that obviates the need for expensive and no longer produced zero-overcoat soft x-ray emulsion film. In a typical experiment the desired spectral energy cuts, signal intensity levels, and desired field of view will determine diagnostic geometry and x-ray filters selected. The authors have developed several computer codes to assist in the diagnostic design process and data deconvolution. Examples of the diagnostic design process and data analysis for a typical pulsed power experiment are presented.

  18. X-ray Spectral Properties of the BAT AGN Sample

    E-Print Network [OSTI]

    L. M. Winter; R. Mushotzky; C. S. Reynolds; J. Tueller

    2008-08-04

    The 9-month Swift Burst Alert Telescope (BAT) catalog provides the first unbiased (log N_H = 0.03) AGN. In this paper, we present the collected X-ray properties (0.3 - 12keV) for the 153 AGN detected. In addition, we examine the X-ray properties for a complete sample of non-beamed sources, above the Galactic plane. Of these, 45% are best fit by simple power law models while 55% require the more complex partial covering model. One of our goals was to determine the fraction of "hidden" AGN, which we define as sources with scattering fractions Marshall et al. 1980). From the log N-log S relationship, we show that we are complete to log S < -11 in the 2-10 keV band. Both the collected X-ray properties of our uniform sample and the log N-log S relationship will now provide valuable input to X-ray background models for z ~ 0. (abridged)

  19. Compact X-ray Light Source Workshop Report

    SciTech Connect (OSTI)

    Thevuthasan, Suntharampillai; Evans, James E.; Terminello, Louis J.; Koppenaal, David W.; Manke, Kristin L.; Plata, Charity

    2012-12-01

    This report, produced jointly by EMSL and FCSD, is the result of a workshop held in September 2011 that examined the utility of a compact x-ray light source (CXLS) in addressing many scientific challenges critical to advancing energy science and technology.

  20. The X-ray emission of the gamma Cassiopiae stars

    E-Print Network [OSTI]

    Smith, Myron A; Motch, C

    2015-01-01

    Long considered as the "odd man out" among X-ray emitting Be stars, \\gamma Cas (B0.5e\\,IV) is now recognized as the prototype of a class of stars that emit hard thermal X-rays. Our classification differs from the historical use of the term "gamma Cas stars" defined from optical properties alone. The luminosity output of this class contributes significantly to the hard X-ray production of massive stars in the Galaxy. The gamma Cas stars have light curves showing variability on a few broadly-defined timescales and spectra indicative of an optically thin plasma consisting of one or more hot thermal components. By now 9--13 Galactic \\approx B0-1.5e main sequence stars are judged to be members or candidate members of the \\gc\\ class. Conservative criteria for this designation are for a \\approxB0-1.5e III-V star to have an X-ray luminosity of 10^{32}--10^{33} ergs s^{-1}, a hot thermal spectrum containing the short wavelength Ly \\alpha FeXXV and FeXXVI lines and the fluorescence FeK feature all in emission. If therm...

  1. Operational properties of fluctuation X-ray scattering data

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Malmerberg, Erik; Kerfeld, Cheryl A.; Zwart, Petrus H.

    2015-03-20

    X-ray scattering images collected on timescales shorter than rotation diffusion times using a (partially) coherent beam result in a significant increase in information content in the scattered data. These measurements, named fluctuation X-ray scattering (FXS), are typically performed on an X-ray free-electron laser (XFEL) and can provide fundamental insights into the structure of biological molecules, engineered nanoparticles or energy-related mesoscopic materials beyond what can be obtained with standard X-ray scattering techniques. In order to understand, use and validate experimental FXS data, the availability of basic data characteristics and operational properties is essential, but has been absent up to this point.more »In this communication, an intuitive view of the nature of FXS data and their properties is provided, the effect of FXS data on the derived structural models is highlighted, and generalizations of the Guinier and Porod laws that can ultimately be used to plan experiments and assess the quality of experimental data are presented.« less

  2. X-rays at Solid-Liquid Surfaces

    SciTech Connect (OSTI)

    Dosch, Helmut (Max Planck Institute for Metals Research) [Max Planck Institute for Metals Research

    2007-05-02

    Solid-liquid interfaces play an important role in many areas of current and future technologies, and in our biosphere. They play a key role in the development of nanofluidics and nanotribology, which sensitively depend on our knowledge of the microscopic structures and phenomena at the solid-liquid interface. The detailed understanding of how a fluid meets a wall is also a theoretical challenge. In particular, the phenomena at repulsive walls are of interest, since they affect many different phenomena, such as water-repellent surfaces or the role of the hydrophobic interaction in protein folding. Recent x-ray reflectivity studies of various solid-liquid interfaces have disclosed rather intriguiing phenomena, which will be discussed in this lecture: premelting of ice in contact with silica; liquid Pb in contact with Si; water in contact with hydrophobic surfaces. These experiments, carried out with high-energy x-ray microbeams, reveal detailed insight into the liquid density profile closest to the wall. A detailed insight into atomistic phenomena at solid-liquid interfaces is also a prerequisite in the microscopic control of electrochemical reactions at interfaces. Recent x-ray studies show the enormous future potential of such non-destructive analytical tools for the in situ observation of (electro-)chemical surface reactions. This lecture will review recent x-ray experiments on solid-liquid interfaces.

  3. X-ray Emission from the Winds of Massive Stars

    E-Print Network [OSTI]

    Cohen, David

    X-ray Emission from the Winds of Massive Stars David Cohen Department of Physics & Astronomy-driven stellar winds are a characteristic of massive stars NGC 6888 Crescent Nebula - Tony Hallas #12;NGC 6888 Crescent Nebula - Tony Hallas O star - source of wind bubble: ~1 arc second instrumental resolution; star

  4. X-ray characterization of solid small molecule organic materials

    SciTech Connect (OSTI)

    Billinge, Simon; Shankland, Kenneth; Shankland, Norman; Florence, Alastair

    2014-06-10

    The present invention provides, inter alia, methods of characterizing a small molecule organic material, e.g., a drug or a drug product. This method includes subjecting the solid small molecule organic material to x-ray total scattering analysis at a short wavelength, collecting data generated thereby, and mathematically transforming the data to provide a refined set of data.

  5. USE OF DIAGNOSTIC X-RAY FOR DETERMINING

    E-Print Network [OSTI]

    in such studies because of the great amount of tipie and effort required in dissection of vertebral columns of individual fish, but provide a permanent record of the vertebral column for future referenceUSE OF DIAGNOSTIC X-RAY FOR DETERMINING VERTEBRAL NUMBERS OF FISH Marine Biological Labo

  6. Crystal defect studies using x-ray diffuse scattering

    SciTech Connect (OSTI)

    Larson, B.C.

    1980-01-01

    Microscopic lattice defects such as point (single atom) defects, dislocation loops, and solute precipitates are characterized by local electronic density changes at the defect sites and by distortions of the lattice structure surrounding the defects. The effect of these interruptions of the crystal lattice on the scattering of x-rays is considered in this paper, and examples are presented of the use of the diffuse scattering to study the defects. X-ray studies of self-interstitials in electron irradiated aluminum and copper are discussed in terms of the identification of the interstitial configuration. Methods for detecting the onset of point defect aggregation into dislocation loops are considered and new techniques for the determination of separate size distributions for vacancy loops and interstitial loops are presented. Direct comparisons of dislocation loop measurements by x-rays with existing electron microscopy studies of dislocation loops indicate agreement for larger size loops, but x-ray measurements report higher concentrations in the smaller loop range. Methods for distinguishing between loops and three-dimensional precipitates are discussed and possibilities for detailed studies considered. A comparison of dislocation loop size distributions obtained from integral diffuse scattering measurements with those from TEM show a discrepancy in the smaller sizes similar to that described above.

  7. Soft X-ray spectral variability of AM Herculis

    E-Print Network [OSTI]

    K. Beuermann; E. El Kholy; K. Reinsch

    2008-02-19

    Polars (AM Herculis binaries) are a prominent class of bright soft X-ray sources, many of which were discovered with ROSAT. We present a homogenous analysis of all the pointed ROSAT PSPC observations of polars subdivided into two papers that discuss the prototype polar AM Her in detail and summarize the class properties of all other polars. We derive the high-state soft X-ray flux and short-term spectral variability of AM Her using a new detector response matrix and a confirmed flux calibration of the ROSAT PSPC below 0.28 keV. The best-fit mean single-blackbody temperature and integrated bright-phase energy flux of AM Her in its April 1991 high state are 27.2 +/- 1.0 eV and (2.6 +/- 0.6) x 10^-9 erg cm^-2s^-1, respectively. The total blackbody flux of a multi-temperature model that fits both the soft X-ray and the fluctuating far-ultraviolet components is Fbb = (4.5 +/- 1.5) x 10^-9 erg cm^-2s^-1. The total accretion luminosity at a distance of 80 pc, Lbb = (2.1 +/- 0.7) x 10^33 erg s-1, implies an accretion rate of Mdot = (2.4 +/- 0.8) x 10^-10 Msun yr^-1 for an 0.78 Msun white dwarf. The soft X-ray flux displays significant variability on time scales down to 200 ms. Correlated spectral and count-rate variations are seen in flares on time scales down to 1 s, demonstrating the heating and cooling associated with individual accretion events. Our spectral and temporal analysis provides direct evidence for the blobby accretion model and suggests a connection between the soft X-ray and the fluctuating far-ultraviolet components.

  8. X-ray ablation measurements and modeling for ICF applications

    SciTech Connect (OSTI)

    Anderson, A.T.

    1996-09-01

    X-ray ablation of material from the first wall and other components of an ICF (Inertial Confinement Fusion) chamber is a major threat to the laser final optics. Material condensing on these optics after a shot may cause damage with subsequent laser shots. To ensure the successful operation of the ICF facility, removal rates must be predicted accurately. The goal for this dissertation is to develop an experimentally validated x-ray response model, with particular application to the National Ignition Facility (NIF). Accurate knowledge of the x-ray and debris emissions from ICF targets is a critical first step in the process of predicting the performance of the target chamber system. A number of 1-D numerical simulations of NIF targets have been run to characterize target output in terms of energy, angular distribution, spectrum, and pulse shape. Scaling of output characteristics with variations of both target yield and hohlraum wall thickness are also described. Experiments have been conducted at the Nova laser on the effects of relevant x-ray fluences on various materials. The response was diagnosed using post-shot examinations of the surfaces with scanning electron microscope and atomic force microscope instruments. Judgments were made about the dominant removal mechanisms for each material. Measurements of removal depths were made to provide data for the modeling. The finite difference ablation code developed here (ABLATOR) combines the thermomechanical response of materials to x-rays with models of various removal mechanisms. The former aspect refers to energy deposition in such small characteristic depths ({approx} micron) that thermal conduction and hydrodynamic motion are significant effects on the nanosecond time scale. The material removal models use the resulting time histories of temperature and pressure-profiles, along with ancillary local conditions, to predict rates of surface vaporization and the onset of conditions that would lead to spallation.

  9. An axisymmetric hydrodynamical model for the torus wind in AGN. II: X-ray excited funnel flow

    E-Print Network [OSTI]

    A. Dorodnitsyn; T. Kallman; D. Proga

    2008-06-23

    We have calculated a series of models of outflows from the obscuring torus in active galactic nuclei (AGN). Our modeling assumes that the inner face of a rotationally supported torus is illuminated and heated by the intense X-rays from the inner accretion disk and black hole. As a result of such heating a strong biconical outflow is observed in our simulations. We calculate 3-dimensional hydrodynamical models, assuming axial symmetry, and including the effects of X-ray heating, ionization, and radiation pressure. We discuss the behavior of a large family of these models, their velocity fields, mass fluxes and temperature, as functions of the torus properties and X-ray flux. Synthetic warm absorber spectra are calculated, assuming pure absorption, for sample models at various inclination angles and observing times. We show that these models have mass fluxes and flow speeds which are comparable to those which have been inferred from observations of Seyfert 1 warm absorbers, and that they can produce rich absorption line spectra.

  10. XMM-NEWTON X-RAY AND ULTRAVIOLET OBSERVATIONS OF THE FAST NOVA V2491 Cyg DURING THE SUPERSOFT SOURCE PHASE

    SciTech Connect (OSTI)

    Ness, J.-U. [XMM-Newton Science Operations Centre, ESA, Madrid (Spain); Osborne, J. P.; Page, K. L.; Beardmore, A. P. [Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Dobrotka, A. [Department of Physics, Institute of Materials Science, Faculty of Materials Science and Technology, Slovak University of Technology in Bratislava, 91724 Trnava (Slovakia); Drake, J. J. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Pinto, C.; Detmers, R. G. [SRON Netherlands Institute for Space Research, 3584 CA Utrecht (Netherlands); Schwarz, G. [American Astronomical Society, Washington, DC 20009-1231 (United States); Bode, M. F. [Astrophysics Research Institute, Liverpool John Moores University, Birkenhead CH41 1LD (United Kingdom); Starrfield, S. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Hernanz, M. [Institut de Ciencies de l'Espai (CSIC-IEEC), Campus UAB, Facultat de Ciencies, 08193 Bellaterra (Barcelona) (Spain); Sala, G. [Departament Fisica i Enginyeria Nuclear, EUETIB (UPC-IEEC), 08036 Barcelona (Spain); Krautter, J. [Landessternwarte Koenigstuhl, Universitaet Heidelberg, D-69117 Heidelberg (Germany); Woodward, C. E. [Department of Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2011-05-20

    Two XMM-Newton observations of the fast classical nova V2491 Cyg were carried out in short succession on days 39.93 and 49.62 after discovery, during the supersoft source (SSS) phase, yielding simultaneous X-ray and UV light curves and high-resolution X-ray spectra. The first X-ray light curve is highly variable, showing oscillations with a period of 37.2 minutes after an extended factor of three decline lasting {approx}3 hr, while the second X-ray light curve is less variable. The cause of the dip is currently unexplained and has most likely the same origin as similar events in the early SSS light curves of the novae V4743 Sgr and RS Oph, as it occurred on the same timescale. The oscillations are not present during the dip minimum and also not in the second observation. The UV light curves are variable but contain no dips and no period. High-resolution X-ray spectra are presented for four intervals of differing intensity. All spectra are atmospheric continua with deep absorption lines and absorption edges. Two interstellar lines of O I and N I are clearly seen at their rest wavelengths, while a large number of high-ionization absorption lines are found at blueshifts indicating an expansion velocity of 3000-3400 km s{sup -1}, which does not change significantly during the epochs of observation. Comparisons with the slower nova V4743 Sgr and the symbiotic recurrent nova RS Oph are presented. The SSS spectrum of V4743 Sgr is much softer with broader and more complex photospheric absorption lines. The ejecta are extended, allowing us to view a larger range of the radial velocity profile. Meanwhile, the absorption lines in RS Oph are as narrow as in V2491 Cyg, but they are less blueshifted. A remarkable similarity in the continua of V2491 Cyg and RS Oph is found. The only differences are smaller line shifts and additional emission lines in RS Oph that are related to the presence of a dense stellar wind from the evolved companion. Three unidentified absorption lines are present in the X-ray spectra of all three novae, with projected rest wavelengths 26.05 A, 29.45 A, and 30.0 A. No entirely satisfactory spectral model is currently available for the soft X-ray spectra of novae in outburst, and careful discussion of assumptions is required.

  11. X-ray crystal structure and small-angle X-ray scattering of sheep liver sorbitol dehydrogenase

    SciTech Connect (OSTI)

    Yennawar, Hemant [Pennsylvania State University, 8 Althouse Laboratory, University Park, PA 16802 (United States); Møller, Magda [Cornell High Energy Synchrotron Source, Ithaca, NY 14853 (United States); University of Copenhagen, DK-2100 Copenhagen (Denmark); Gillilan, Richard [Cornell High Energy Synchrotron Source, Ithaca, NY 14853 (United States); Yennawar, Neela, E-mail: nhy1@psu.edu [Pennsylvania State University, 8 Althouse Laboratory, University Park, PA 16802 (United States)

    2011-05-01

    The X-ray crystal structure and a small-angle X-ray scattering solution structure of sheep liver sorbitol dehydrogenase have been determined. The details of the interactions that enable the tetramer scaffold to be the functional biological unit have been analyzed. The X-ray crystal structure of sheep liver sorbitol dehydrogenase (slSDH) has been determined using the crystal structure of human sorbitol dehydrogenase (hSDH) as a molecular-replacement model. slSDH crystallized in space group I222 with one monomer in the asymmetric unit. A conserved tetramer that superposes well with that seen in hSDH (despite belonging to a different space group) and obeying the 222 crystal symmetry is seen in slSDH. An acetate molecule is bound in the active site, coordinating to the active-site zinc through a water molecule. Glycerol, a substrate of slSDH, also occupies the substrate-binding pocket together with the acetate designed by nature to fit large polyol substrates. The substrate-binding pocket is seen to be in close proximity to the tetramer interface, which explains the need for the structural integrity of the tetramer for enzyme activity. Small-angle X-ray scattering was also used to identify the quaternary structure of the tetramer of slSDH in solution.

  12. X-ray diffraction, spectroscopic and DFT studies of 1-(4-bromophenyl)-3,5-diphenylformazan

    SciTech Connect (OSTI)

    Tezcan, H.; Tokay, N.; Alpaslan, G.; Erdönmez, A.

    2013-12-15

    The crystal structure of 1-(4-bromophenyl)-3,5-diphenylformazan was determined by X-ray single crystal diffraction technique. The crystals are orthorhombic, a = 23.0788(9), b = 7.9606(3), c = 18.6340(12) Å, Z = 8, sp. gr. Pbca, R{sub 1} = 0.074. The structure was also examined using the density-functional theory. Its structure stability, and frontier molecular orbital components were discussed and the results were compared with X-ray and spectral results. The maximum absorbtion peaks of the UV-vis spectrum of the compound have been calculated using the time-dependent density-functional theory. It was found a good agreement between the calculated and experimental maximum absorption wavelength.

  13. Linear Theory Analysis of Self-Amplified Parametric X-ray Radiation from High Current Density Electron Bunches

    E-Print Network [OSTI]

    Lobach, Ihar; Feranchuk, Ilya

    2015-01-01

    Linear theory of the parametric beam instability or the self-amplification of parametric x-ray radiation (PXR) from relativistic electrons in a crystal is considered taking into account finite emittance of the electron beam and absorption of the radiation. It is shown that these factors change essentially the estimation of threshold parameters of the electron bunches for the coherent X-ray generation. The boundary conditions for the linear theory of the effect is analyzed in details and it is shown that the grazing incidence diffraction geometry is optimal for the growth of instability. Numerical estimations of amplification and coherent photon yield in dependence on the electron current density are presented for the case of mm-thickness Si crystal and 100 MeV electrons. Possible improvements of the experimental scheme for optimization of the coherent radiation intensity are discussed.

  14. Polarity characterization by anomalous x-ray dispersion of ZnO films and GaN lateral polar structures

    SciTech Connect (OSTI)

    Shelton, Christopher T.; Sachet, Edward; Paisley, Elizabeth A.; Hoffmann, Marc P.; Rajan, Joseph; Collazo, Ramón; Sitar, Zlatko; Maria, Jon-Paul

    2014-01-28

    We demonstrate the use of anomalous x-ray scattering of constituent cations at their absorption edge, in a conventional Bragg-Brentano diffractometer, to measure absolutely and quantitatively the polar orientation and polarity fraction of unipolar and mixed polar wurtzitic crystals. In one set of experiments, the gradual transition between c+ and c? polarity of epitaxial ZnO films on sapphire as a function of MgO buffer layer thickness is monitored quantitatively, while in a second experiment, we map the polarity of a lateral polar homojunction in GaN. The dispersion measurements are compared with piezoforce microscopy images, and we demonstrate how x-ray dispersion and scanning probe methods can provide complementary information that can discriminate between polarity fractions at a material surface and polarity fractions averaged over the film bulk.

  15. Design and imaging performance of achromatic diffractive/refractive X-ray and Gamma-ray Fresnel lenses

    E-Print Network [OSTI]

    Gerald K. Skinner

    2004-07-21

    Achromatic combinations of a diffractive Phase Fresnel Lens and a refractive correcting element have been proposed for X-ray and gamma-ray astronomy and for microlithography, but considerations of absorption often dictate that the refractive component be given a stepped profile, resulting in a double Fresnel lens. The imaging performance of corrected Fresnel lenses, with and without `stepping' is investigated and the trade-off between resolution and useful bandwidth in different circumstances is discussed. Provided the focal ratio is large, correction lenses made of low atomic number materials can be used with X-rays in the range approximately 10--100 keV without stepping. The use of stepping extends the possibility of correction to higher aperture systems, to energies as low as a few kilo electron volts and to gamma-rays of $\\sim$ mega electron volt energy.

  16. Dynamic in-situ X-ray Diffraction of Catalyzed Alanates

    SciTech Connect (OSTI)

    Gross, K.J.; Sandrock, G.; Thomas, G.J.

    2000-11-01

    The discovery that hydrogen can be reversible absorbed and desorbed from NaAlH{sub 4} by the addition of catalysts has created an entirely new prospect for lightweight hydrogen storage. NaAlH{sub 4} releases hydrogen through the following set of decomposition reactions: NaAlH{sub 4} {r_arrow} 1/3({alpha}-Na{sub 3}AlH{sub 6}) + 2/3Al + H{sub 2} {r_arrow} NaH + Al + 3/2H{sub 2}. These decomposition reactions as well as the reverse recombination reactions were directly observed using time-resolved in-situ x-ray powder diffraction. These measurements were performed under conditions similar to those found in PEM fuel cell operations (hydrogen absorption: 50--70 C, 10--15 bar Hz, hydrogen resorption: 80--110 C, 5--100 mbar H{sub 2}). Catalyst doping was found to dramatically improve kinetics under these conditions. In this study, the alanate was doped with a catalyst by dry ball-milling NaAlH{sub 4} with 2 mol.% solid TiCl{sub 3}. X-ray diffraction clearly showed that TiCl{sub 3} reacts with NaAlH{sub 4} to form NaCl during the doping process. Partial desorption of NaAlH{sub 4} was even observed to occur during the catalyst doping process.

  17. Probing hot-electron effects in wide area plasmonic surfaces using X-ray photoelectron spectroscopy

    SciTech Connect (OSTI)

    Ayas, Sencer; Cupallari, Andi; Dana, Aykutlu

    2014-12-01

    Plasmon enhanced hot carrier formation in metallic nanostructures increasingly attracts attention due to potential applications in photodetection, photocatalysis, and solar energy conversion. Here, hot-electron effects in nanoscale metal-insulator-metal (MIM) structures are investigated using a non-contact X-ray photoelectron spectroscopy based technique using continuous wave X-ray and laser excitations. The effects are observed through shifts of the binding energy of the top metal layer upon excitation with lasers of 445, 532, and 650?nm wavelength. The shifts are polarization dependent for plasmonic MIM grating structures fabricated by electron beam lithography. Wide area plasmonic MIM surfaces fabricated using a lithography free route by the dewetting of evaporated Ag on HfO{sub 2} exhibit polarization independent optical absorption and surface photovoltage. Using a simple model and making several assumptions about the magnitude of the photoemission current, the responsivity and external quantum efficiency of wide area plasmonic MIM surfaces are estimated as 500?nA/W and 11 × 10{sup ?6} for 445?nm illumination.

  18. Thermal and Bulk Comptonization in Accretion-Powered X-Ray Pulsars

    E-Print Network [OSTI]

    Peter A. Becker; Michael T. Wolff

    2006-09-01

    We develop a new theoretical model for the spectral formation process in accretion-powered X-ray pulsars based on a detailed treatment of the bulk and thermal Comptonization occurring in the accreting, shocked gas. A rigorous eigenfunction expansion method is employed to obtain the analytical solution for the Green's function describing the scattering of radiation injected into the column from a monochromatic source located at an arbitrary height above the stellar surface. The emergent spectrum is calculated by convolving the Green's function with source terms corresponding to bremsstrahlung, cyclotron, and blackbody emission. The energization of the photons in the shock, combined with cyclotron absorption, naturally produces an X-ray spectrum with a relatively flat continuum shape and a high-energy quasi-exponential cutoff. We demonstrate that the new theory successfully reproduces the phase-averaged spectra of the bright pulsars Her X-1, LMC X-4, and Cen X-3. In these luminous sources, it is shown that the emergent spectra are dominated by Comptonized bremsstrahlung emission.

  19. Swift-UVOT Observations of the X-Ray Flash 050406

    E-Print Network [OSTI]

    Schady, P; Osborne, J P; Page, M J; Roming, P W A; Still, M; Zhang, B; Blustin, A J; Boyd, P; Cucchiara, A; Gehrels, N; Gronwall, C; De Pasquale, M; Holland, S T; Marshall, F E; McGowan, K E; Nousek, J A

    2006-01-01

    We present Swift-UVOT data on the optical afterglow of the X-ray flash of 2005 April 6 (XRF 050406) from 88s to \\sim 10^5s after the initial prompt gamma-ray emission. Our observations in the V, B and U bands are the earliest that have been taken of an XRF optical counterpart. Combining the early -time optical temporal and spectral properties with \\gamma- and simultaneous X-ray data taken with the BAT and XRT telescopes on-board Swift, we are able to constrain possible origins of the XRF. The prompt emission had a FRED profile (fast-rise, exponential decay) with a duration of T_90 = 5.7\\pm 0.2s, putting it at the short end of the long-burst duration distribution. The absence of photoelectric absorption red-ward of 4000 \\AA in the UV/optical spectrum provides a firm upper limit of z\\leq 3.1 on the redshift, thus excluding a high redshift as the sole reason for the soft spectrum. The optical light curve is consistent with a power-law decay with slope alpha = -0.75\\pm 0.26 (F_{\

  20. Swift-UVOT Observations of the X-Ray Flash 050406

    E-Print Network [OSTI]

    P. Schady; K. O. Mason; J. P. Osborne; M. J. Page; P. W. A. Roming; M. Still; B. Zhang; A. J. Blustin; P. Boyd; A. Cucchiara; N. Gehrels; C. Gronwall; M. De Pasquale; S. T. Holland; F. E. Marshall; K. E. McGowan; J. A. Nousek

    2006-03-21

    We present Swift-UVOT data on the optical afterglow of the X-ray flash of 2005 April 6 (XRF 050406) from 88s to \\sim 10^5s after the initial prompt gamma-ray emission. Our observations in the V, B and U bands are the earliest that have been taken of an XRF optical counterpart. Combining the early -time optical temporal and spectral properties with \\gamma- and simultaneous X-ray data taken with the BAT and XRT telescopes on-board Swift, we are able to constrain possible origins of the XRF. The prompt emission had a FRED profile (fast-rise, exponential decay) with a duration of T_90 = 5.7\\pm 0.2s, putting it at the short end of the long-burst duration distribution. The absence of photoelectric absorption red-ward of 4000 \\AA in the UV/optical spectrum provides a firm upper limit of z\\leq 3.1 on the redshift, thus excluding a high redshift as the sole reason for the soft spectrum. The optical light curve is consistent with a power-law decay with slope alpha = -0.75\\pm 0.26 (F_{\