Sample records for x-ray spectroscopy instrumentation

  1. Photon Spectroscopy with Imaging X-Ray Instruments

    Microsoft Academic Search

    B. J. Labonte; K. P. Reardon

    2007-01-01

    Individual X-ray photons in the keV energy range produce hundreds of photoelectrons in a single pixel of a CCD array detector.\\u000a The number of photoelectrons produced is a linear function of the photon energy, allowing the measurement of spectral information\\u000a with an imaging detector system. Most solar X-ray telescopes, such as Yohkoh\\/SXT and Hinode\\/XRT, use CCD detectors in an integrating

  2. Photon Spectroscopy with Imaging X-Ray Instruments

    Microsoft Academic Search

    B. J. Labonte; K. P. Reardon

    2007-01-01

    Individual X-ray photons in the keV energy range produce hundreds of photoelectrons in a single pixel of a CCD array detector. The number of photoelectrons produced is a linear function of the photon energy, allowing the measurement of spectral information with an imaging detector system. Most solar X-ray telescopes, such as Yohkoh\\/SXT and Hinode\\/XRT, use CCD detectors in an integrating

  3. The X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source

    PubMed Central

    Alonso-Mori, Roberto; Caronna, Chiara; Chollet, Matthieu; Curtis, Robin; Damiani, Daniel S.; Defever, Jim; Feng, Yiping; Flath, Daniel L.; Glownia, James M.; Lee, Sooheyong; Lemke, Henrik T.; Nelson, Silke; Bong, Eric; Sikorski, Marcin; Song, Sanghoon; Srinivasan, Venkat; Stefanescu, Daniel; Zhu, Diling; Robert, Aymeric

    2015-01-01

    The X-ray Correlation Spectroscopy instrument is dedicated to the study of dynamics in condensed matter systems using the unique coherence properties of free-electron lasers. It covers a photon energy range of 4–25?keV. The intrinsic temporal characteristics of the Linac Coherent Light Source, in particular the 120?Hz repetition rate, allow for the investigation of slow dynamics (milli­seconds) by means of X-ray photon correlation spectroscopy. Double-pulse schemes could probe dynamics on the picosecond timescale. A description of the instrument capabilities and recent achievements is presented. PMID:25931061

  4. The X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source.

    PubMed

    Alonso-Mori, Roberto; Caronna, Chiara; Chollet, Matthieu; Curtis, Robin; Damiani, Daniel S; Defever, Jim; Feng, Yiping; Flath, Daniel L; Glownia, James M; Lee, Sooheyong; Lemke, Henrik T; Nelson, Silke; Bong, Eric; Sikorski, Marcin; Song, Sanghoon; Srinivasan, Venkat; Stefanescu, Daniel; Zhu, Diling; Robert, Aymeric

    2015-05-01

    The X-ray Correlation Spectroscopy instrument is dedicated to the study of dynamics in condensed matter systems using the unique coherence properties of free-electron lasers. It covers a photon energy range of 4-25?keV. The intrinsic temporal characteristics of the Linac Coherent Light Source, in particular the 120?Hz repetition rate, allow for the investigation of slow dynamics (milliseconds) by means of X-ray photon correlation spectroscopy. Double-pulse schemes could probe dynamics on the picosecond timescale. A description of the instrument capabilities and recent achievements is presented. PMID:25931061

  5. Photon excitation for satellite free x-ray spectroscopy: Instrumentation challenges

    SciTech Connect

    Perera, R.C.C.

    1991-10-01

    First systematic study of satellites in x-ray emission spectra was performed by Deslattes using quasi-monochromatic photon excitation from a group of L{alpha} x-ray sources lying close to the K edge of Cl. He observed significant alterations in the Cl K{beta} spectrum of KCl depending on the character of the excitation radiation and identified the initial state of these satellites as a double vacancy state. Recently, the valence electronic structure of the chlorofluoromethanes were analyzed by chlorine K x-ray emission under satellite-free conditions. These studies were based on the use of synchrotron radiation to eliminate the multivacancy effects that are inherent in conventional x-ray spectroscopy. In this report, satellite free x-ray emission spectra from chlorofluoromethanes will be presented to demonstrate that the simplified spectra can be obtained using selective photon excitation. Results from various research groups world wide, utilizing the tunable photon excitation form synchrotron sources to eliminate the obscuring features in x-ray emission spectra of rare-gas solids (RGS) and metals will be discussed. Also, the technical challenges in utilizing the small phase-space attributes of high brightness from third generation SR sources producing x-ray and vacuum ultra-violet wavelengths to study weak features like satellites in x-ray emission spectra will be presented.

  6. New Concepts for X-Ray, Soft X-Ray, and EUV Optical Instrumentation Including Applications in Spectroscopy, Plasma Diagnostics, and Biomedical Microscopy: A Status Report

    Microsoft Academic Search

    V. L. Kantsyrev; R. Bruch; R. Phaneuf; N. G. Publicover

    1997-01-01

    In this article, we review current progress in the development of several techniques for extreme ultraviolet, soft x-ray, and x-ray optical instrumentation. Applications of these concepts include diagnostics of hot plasmas, spectroscopic studies of the interaction of multicharged ion beams with matter (atoms, ions, molecules, microstructures, surfaces, solids), and biomedical x-ray microscopy. Novel applications of components include the use of

  7. X-ray spectroscopy of low-mass X-ray binaries

    E-print Network

    Juett, Adrienne Marie, 1976-

    2004-01-01

    I present high-resolution X-ray grating spectroscopy of neutron stars in low-mass X-ray binaries (LMXBs) using instruments onboard the Chandra X-ray Observatory and the X-ray Multi-Mirror Mission (XMM-Newton). The first ...

  8. X-ray Absorption Spectroscopy

    SciTech Connect

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  9. X-ray astronomical spectroscopy

    NASA Technical Reports Server (NTRS)

    Holt, S. S.

    1980-01-01

    The current status of the X-ray spectroscopy of celestial X-ray sources, ranging from nearby stars to distant quasars, is reviewed. Particular emphasis is placed on the role of such spectroscopy as a useful and unique tool in the elucidation of the physical parameters of the sources. The spectroscopic analysis of degenerate and nondegenerate stellar systems, galactic clusters and active galactic nuclei, and supernova remnants is discussed.

  10. X-Ray Absorption Spectroscopy of Metallobiomolecules

    E-print Network

    Scott, Robert A.

    2/9/07 1 X-Ray Absorption Spectroscopy of Metallobiomolecules The Outskirts of Structural Biology 9, 07] This is a tutorial about the use of X-ray Absorption Spectroscopy (XAS) in biology, RG; Eisenberger, P; Kincaid, BM "X-ray Absorption Spectroscopy of Biological Molecules" Annu. Rev

  11. X-Ray Absorption Spectroscopy of Metallobiomolecules

    E-print Network

    Scott, Robert A.

    9/6/09 1 X-Ray Absorption Spectroscopy of Metallobiomolecules The Outskirts of Structural Biology 6, 09] This is a tutorial about the use of X-ray Absorption Spectroscopy (XAS) in biology, RG; Eisenberger, P; Kincaid, BM "X-ray Absorption Spectroscopy of Biological Molecules" Annu. Rev

  12. Application of X-ray Optics to Energy-Dispersive Spectroscopy

    Microsoft Academic Search

    Jon J. McCarthy; David J. McMillan

    1998-01-01

    : X-ray optics have been used in X-ray analytical instruments for several years. Applications of X-ray optics have been reported in X-ray diffraction, X-ray fluorescence, and wavelength dispersive spectroscopy. X-ray optics have been used to increase the X-ray flux incident on the sample or to direct and focus emitted X-rays from a sample. We report here the use of a

  13. X-ray astronomical spectroscopy

    NASA Technical Reports Server (NTRS)

    Holt, Stephen S.

    1987-01-01

    The contributions of the Goddard group to the history of X-ray astronomy are numerous and varied. One role that the group has continued to play involves the pursuit of techniques for the measurement and interpretation of the X-ray spectra of cosmic sources. The latest development is the selection of the X-ray microcalorimeter for the Advanced X-ray Astrophysics Facility (AXAF) study payload. This technology is likely to revolutionize the study of cosmic X-ray spectra.

  14. Resonant x-ray emission spectroscopy of liquid water: novel instrumentation, high resolution, and the"map" approach

    SciTech Connect

    Weinhardt, L.; Fuchs, O.; Blum, M.; Bär, M.; Weigand, M.; Denlinger, J.D.; Zubavichus, Y.; Zharnikov, M.; Grunze, M.; Heske, C.; Umbach, E.

    2008-06-17

    Techniques to study the electronic structure of liquids are rare. Most recently, resonant x-ray emission spectroscopy (XES) has been shown to be an extremely versatile spectroscopy to study both occupied and unoccupied electronic states for liquids in thermodynamic equilibrium. However, XES requires high-brilliance soft x-ray synchrotron radiation and poses significant technical challenges to maintain a liquid sample in an ultra-high vacuum environment. Our group has therefore developed and constructed a novel experimental setup for the study of liquids, with the long-term goal of investigating the electronic structure of biological systems in aqueous environments. We have developed a flow-through liquid cell in which the liquid is separated from vacuum by a thin Si3N4 or SiC window and which allows a precise control of temperature. This approach has significant advantages compared to static liquids cells used in the past. Furthermore, we have designed a dedicated high-transmission, high-resolution soft x-ray spectrometer. The high transmission makes it possible to measure complete resonant XES"maps" in less than an hour, giving unprecedented detailed insight into the electronic structure of the investigated sample. Using this new equipment we have investigated the electronic structure of liquid water. Furthermore, our XES spectra and maps give information about ultra-fast dissociation on the timescale of the O 1s core hole lifetime, which is strongly affected by the initial state hydrogen bonding configuration.

  15. Large Area X-ray Spectroscopy Mission

    NASA Technical Reports Server (NTRS)

    Tananbaum, Harvey

    1996-01-01

    The Large Area X-ray Spectroscopy (LAXS) mission study concept has evolved strongly over the last year culminating in the merging of LAXS with the Goddard Space Flight Center (GSFC) proposal for a similar mission, the Next Generation X-ray Observatory (NGXO, PI: Nick White). The resulting merger, re-named the High Throughput X-rays Spectroscopy (HTXS) Mission has also expanded by the inclusion of another SAO proposed new mission concept proposal, the Hard X-Ray Telescope (PI: Paul Gorenstein). The resultant multi-instrument mission retains much of heritage from the LAXS proposal, including the use of multiple satellites for robustness. These mergers resulted from a series of contacts between various team members, via e-mail, telecons, and in-person meetings. The impetus for the mergers was the fundamental similarity between the missions, and the recognition that all three proposal teams had significant contributions to make in the effort to define the next stage in the X-ray exploration of the universe. We have enclosed four items that represent some of the work that has occurred during the first year of the study: first, a presentation at the Leicester meeting, second a presentation that was made to Dan Goldin following the merging of LAXS and NGXO, third a copy of the first announcement for the Workshop, and finally the interim report that was prepared by the HTXS study team towards the end of the first year. This last document provides the foundation for the HTXS Technology Roadmap that is being generated. The HTXS roadmap will define the near-term goals that the merged mission must achieve over the next few years. A web site has been developed and populated that contains much of the material that has been generated over the past year.

  16. Instrumental technique in X-ray astronomy

    NASA Technical Reports Server (NTRS)

    Peterson, L. E.

    1975-01-01

    A detailed review of the development of instruments for X-ray astronomy is given with major emphasis on nonfocusing high-sensitivity counter techniques used to detect cosmic photons in the energy range between 0.20 and 300 keV. The present status of X-ray astronomy is summarized together with significant results of the Uhuru observations, and photon interactions of importance for the detection of X-rays in space are noted. The three principal devices used in X-ray astronomy (proportional, scintillation, and solid-state counters) are described in detail, data-processing systems for these devices are briefly discussed, and the statistics of nuclear counting as applied to X-ray astronomy is outlined analytically. Effects of the near-earth X-ray environment and atmospheric gamma-ray production on X-ray detection by low-orbit satellites are considered. Several contemporary instruments are described (proportional-counter systems, scintillation-counter telescopes, modulation collimators), and X-ray astronomical satellite missions are tabulated.

  17. X-ray Spectroscopy of Cooling Cluster

    SciTech Connect

    Peterson, J.R.; /SLAC; Fabian, A.C.; /Cambridge U., Inst. of Astron.

    2006-01-17

    We review the X-ray spectra of the cores of clusters of galaxies. Recent high resolution X-ray spectroscopic observations have demonstrated a severe deficit of emission at the lowest X-ray temperatures as compared to that expected from simple radiative cooling models. The same observations have provided compelling evidence that the gas in the cores is cooling below half the maximum temperature. We review these results, discuss physical models of cooling clusters, and describe the X-ray instrumentation and analysis techniques used to make these observations. We discuss several viable mechanisms designed to cancel or distort the expected process of X-ray cluster cooling.

  18. Ultrafast X-ray Absorption Spectroscopy using Laser-Driven Electron X-ray Sources (LEXS)

    E-print Network

    Guo, Ting

    Ultrafast X-ray Absorption Spectroscopy using Laser-Driven Electron X-ray Sources (LEXS) Guangjun: ultrafast x-rays, x-ray absorption spectroscopy, terawatt lasers, ultrafast reaction dynamics, atomic motion Shields Avenue, Davis, CA 95616 ABSTRACT A laser driven electron x-ray source (LEXS) using a high

  19. Global spectroscopy and imaging of atmospheric X-ray bremsstrahlung - Instrumentation and initial results from the PEM/AXIS instrument aboard the Upper Atmosphere Research Satellite

    NASA Technical Reports Server (NTRS)

    Chenette, D. L.; Datlowe, D. W.; Imhof, W. L.; Schumaker, T. L.; Tobin, J. D.

    1992-01-01

    The Atmospheric X-ray Imaging Spectrometer (PEM/AXIS) aboard NASA's Upper Atmosphere Research Satellite provides continuous horizon to horizon images, both day and night, of the 3- to 100-keV X-ray flux emitted from the top of the atmosphere. AXIS achieves a spatial resolution to better than 100 km using a one-dimensional array of 16 passively cooled silicon detectors. The primary purpose of this instrument is to provide a global monitor of electron energy input to the upper atmosphere. We describe the design, development, and calibration of AXIS and provide an assessment of its excellent on-orbit performance. The unique capabilities of X-ray imaging spectrometers are demonstrated through an analysis of specific examples from October and November 1991. Important new developments for follow-on instruments also will be described.

  20. Current Status of AIST X-ray-Absorption-Spectroscopy (XAFS) Instrument with 100-Pixel Superconducting-Tunnel-Junction Array Detector

    NASA Astrophysics Data System (ADS)

    Shiki, S.; Ukibe, M.; Matsubayashi, N.; Zen, N.; Koike, M.; Kitajima, Y.; Ohkubo, M.

    2014-08-01

    We constructed a fluorescence yield X-ray absorption fine structure (XAFS) apparatus for the measurement of local structure around trace light element impurities in light element matrices. Our XAFS instrument with a 100-pixel STJ detector is now in the stage of routine operation and open to users at a synchrotron radiation facility (KEK PF). The average energy resolution of the 100 pixels is 11.8 0.6 at 400 eV in a sensitive area of 1 mm. As an example of functional materials, we successfully measured nitrogen K-edge XAFS spectra of a compound semiconductor, 4H-SiC, with a nitrogen dopant concentration of 300 ppm. The faint N-K line was clearly separated from the strong C-K line.

  1. Large Area X-Ray Spectroscopy Mission

    NASA Technical Reports Server (NTRS)

    Tananbaum, H.

    1997-01-01

    The Large Area X-ray Spectroscopy (LAXS) mission concept study continues to evolve strongly following the merging of the LAXS mission with the Next Generation X-ray Observatory (NGXO, PI: Nick White) into the re-named High Throughput X-ray Spectroscopy (HTXS) Mission. HTXS retains key elements of the LAXS proposal, including the use of multiple satellites for risk-reduction and cost savings. A key achievement of the program has been the recommendation by the Structure and Evolution of the Universe (SEUS) (April 1997) for a new start for the HTXS mission in the 2000-2004 timeframe.

  2. X-ray spectroscopy of NGC 5548

    Microsoft Academic Search

    J. S. Kaastra; K. C. Steenbrugge; A. J. J. Raassen; Meer van der R. L. J; A. C. Brinkman; D. A. Liedahl; E. Behar; A. de Rosa

    2002-01-01

    We analyze the high-resolution X-ray spectrum of the Seyfert 1 galaxy NGC\\u000a5548, for the full 0.1-10 keV band, using improved calibration results of the\\u000aChandra-LETGS instrument. The warm absorber consists of at least three\\u000aionization components, namely one with a low, medium and high ionization\\u000aparameter. The X-ray absorbing material, from an outflowing wind, covers the\\u000afull range of

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

    PubMed

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

    2014-11-01

    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(6)-10(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. PMID:25430123

  4. TENDER ENERGY X-RAY ABSORPTION SPECTROSCOPY (TES)

    E-print Network

    Ohta, Shigemi

    closely with ISS (NEXT beamline for high-flux hard X-ray spectroscopies), XFM (hard X-ray microTENDER ENERGY X-RAY ABSORPTION SPECTROSCOPY (TES) Project Team: S. Bare1,2, J. Brandes3, T-ray absorption spectroscopy and spatially-resolved XAS of structured materials; optimized for the "tender" energy

  5. Biomedical Applications of X-ray Microscopy and X-ray Absorption Spectroscopy

    Microsoft Academic Search

    Peter A. Lay; Carolyn T. Dillon; Hugh H. Harris; Jade B. Aitken; Aviva Levina; Irma Mulyani; Barry Lai; Zhonghou Cai; Stefan Vogt; Paul K. Witting; Shane Thomas; Roland Stocker; Harold Eastgate; Concord NSW

    2006-01-01

    Hard X-ray microprobe techniques: synchrotron-induced X-ray emission (SRIXE) for elemental mapping at a sub-micron level; and micro-XANES (X-ray absorption near-edge structure); are providing unprecedented information on biotransformations of drugs, toxins and carcinogens, as well as normal biological processes and disease conditions at the molecular and cellular levels. These microscopy-based techniques have been combined with X-ray absorption spectroscopy (XAS) on isolated

  6. Soft x-ray time-resolved spectroscopy

    Microsoft Academic Search

    Hai Zhang; Q. L. Yang; B. P. Guo; Han-Ben Niu; Jingzhen Li; Y. C. Wang; Zhong X. Song; Z. L. Liu

    1993-01-01

    The soft x-ray time-resolved spectroscopy is composed of a soft x-ray spectroscopic head and a soft x-ray streak camera. Because the soft x-ray spectroscopic head possesses a spectral resolution of 0.1 angstrom, the performances of the whole system mainly depend on the characteristics of the soft x-ray streak camera. In this paper, therefore, the design features and characterization of the

  7. X-Ray Spectroscopy of Photoionized Plasmas

    NASA Technical Reports Server (NTRS)

    Kallman, Tim

    2008-01-01

    Spectroscopy allows study of sources on small spatial scales, and can provide detailed diagnostic information about elemental abundances, temperature, density and gas dynamics. For compact sources such as accreting black holes in active galactic nuclei (AGN) and X-ray binaries X-ray spectra provide truly unique insight. Observations using Chandra and XMM have revealed components of gas in these systems which were previously unknown or poorly studied. Interpretation of these data presents modeling and analysis challenges, and requires an understanding of atomic physics, ionization and spectrum formation in a radiation-dominated environment. In this talk I will discuss examples, and how they have contributed to our understanding of accreting sources and the nearby gas.

  8. Development and applications of grazing exit micro X-ray fluorescence instrument using a polycapillary X-ray lens

    Microsoft Academic Search

    T. Emoto; Y. Sato; Y. Konishi; X. Ding; K. Tsuji

    2004-01-01

    A polycapillary X-ray lens is an effective optics to obtain a ?m-size X-ray beam for micro-X-ray fluorescence spectrometry (?-XRF). We developed a ?-XRF instrument using a polycapillary X-ray lens, which also enabled us to perform Grazing Exit ?-XRF (GE-?-XRF). The evaluated diameter of the primary X-ray beam was 48 ?m at the focal distance of the X-ray lens. Use of

  9. X-ray spectroscopy of astrophysical plasmas.

    PubMed

    Kahn, Steven M; Behar, Ehud; Kinkhabwala, Ali; Savin, Daniel W

    2002-09-15

    We provide a qualitative review of key X-ray spectral diagnostics of astrophysical plasmas. We begin with a brief discussion of the two major types of equilibria, collisional ionization and photoionization, and then consider the behaviour of hydrogen-like, helium-like, iron L-shell and iron K-shell transitions for these separate cases. Where possible, we discuss explicit examples using high-resolution spectra acquired by the grating instruments on the Chandra and XMM-Newton observatories. PMID:12804237

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

    E-print Network

    Sparks, Donald L.

    Quick extended x-ray absorption fine structure instrument with millisecond time scale, optimized of quick extended x-ray absorption fine structure QEXAFS and quick x-ray absorption near edge structure XANES spectroscopies at beamline X18B at the National Synchrotron Light Source. The channel cut Si 111

  11. Miniaturization in x ray and gamma ray spectroscopy

    NASA Technical Reports Server (NTRS)

    Iwanczyk, Jan S.; Wang, Yuzhong J.; Bradley, James G.

    1993-01-01

    The paper presents advances in two new sensor technologies and a miniaturized associated electronics technology which, when combined, can allow for very significant miniaturization and for the reduction of weight and power consumption in x-ray and gamma-ray spectroscopy systems: (1) Mercuric iodide (HgI2) x-ray technology, which allows for the first time the construction of truly portable, high-energy resolution, non-cryogenic x-ray fluorescence (XRF) elemental analyzer systems, with parameters approaching those of laboratory quality cryogenic instruments; (2) the silicon avalanche photodiode (APD), which is a solid-state light sensitive device with internal amplification, capable of uniquely replacing the vacuum photomultiplier tube in scintillation gamma-ray spectrometer applications, and offering substantial improvements in size, ruggedness, low power operation and energy resolution; and (3) miniaturized (hybridized) low noise, low power amplification and processing electronics, which take full advantage of the favorable properties of these new sensors and allow for the design and fabrication of advanced, highly miniaturized x-ray and gamma-ray spectroscopy systems. The paper also presents experimental results and examples of spectrometric systems currently under construction. The directions for future developments are discussed.

  12. High resolution XUV spectroscopy of x-ray laser plasmas

    SciTech Connect

    Koch, J.A.; Carter, M.R.; Da Silva, L.B.; MacGowan, B.J.; Matthews, D.L.; Mrowka, S.; Scofield, J.H.; Shimkaveg, G.; Walling, R.S. (Lawrence Livermore National Lab., CA (United States)); Batson, P.J.; Chapman, K.L.; Underwood, J.H. (Lawrence Berkeley Lab., CA (United States))

    1991-09-05

    This paper discusses recent progress in LLNL's high resolution XUV spectroscopy efforts with x-ray laser plasmas. We describe the instrumentation used, and we present preliminary time-resolved data on the spectral profiles of several XUV (extreme ultraviolet) lines from Ne-like Se and Ne-like Y x-ray lasers which have been obtained with instrumental resolutions ({lambda}/{Delta}{lambda}) of {approximately}10,000. The Se data indicates that the 206.4 {Angstrom} J = 2 -- 1 laser line narrows below the expected 400 eV Doppler width (35 m{Angstrom}) when amplified through {approximately}6 gain lengths, while the Y data shows no evidence of the J = 0--1 laser predicted to be nearly resonant with the J = 2 -- 1 laser at 154.9 {Angstrom}.

  13. High resolution XUV spectroscopy of x-ray laser plasmas

    SciTech Connect

    Koch, J.A.; Carter, M.R.; Da Silva, L.B.; MacGowan, B.J.; Matthews, D.L.; Mrowka, S.; Scofield, J.H.; Shimkaveg, G.; Walling, R.S. [Lawrence Livermore National Lab., CA (United States); Batson, P.J.; Chapman, K.L.; Underwood, J.H. [Lawrence Berkeley Lab., CA (United States)

    1991-09-05

    This paper discusses recent progress in LLNL`s high resolution XUV spectroscopy efforts with x-ray laser plasmas. We describe the instrumentation used, and we present preliminary time-resolved data on the spectral profiles of several XUV (extreme ultraviolet) lines from Ne-like Se and Ne-like Y x-ray lasers which have been obtained with instrumental resolutions ({lambda}/{Delta}{lambda}) of {approximately}10,000. The Se data indicates that the 206.4 {Angstrom} J = 2 -- 1 laser line narrows below the expected 400 eV Doppler width (35 m{Angstrom}) when amplified through {approximately}6 gain lengths, while the Y data shows no evidence of the J = 0--1 laser predicted to be nearly resonant with the J = 2 -- 1 laser at 154.9 {Angstrom}.

  14. The Uhuru X-Ray Instrument

    Microsoft Academic Search

    N. Jagoda; G. Austin; S. Mickiewicz; R. Goddard

    1972-01-01

    On 12 December 1970, the UHURU (SAS-A) X-ray observatory was launched into equatorial orbit with the prime mission of conducting an all-sky survey of astronomical X-ray sources with intensities of 5 ?? 10-5 Sco-Xl or greater. Featuring two large area proportional counter detector systems, the experiment has operated without a failure and is returning information of great interest to the

  15. AMO instrumentation for the LCLS X-ray FEL

    Microsoft Academic Search

    J. D. Bozek

    2009-01-01

    Instrumentation is being developed to conduct atomic, molecular and optical science experiments at the Linac Coherent Light\\u000a Source x-ray free electron laser at the Stanford Linear Accelerator Center. This suite of instruments will be used to study\\u000a the interaction of the very intense x-ray beam with the simplest forms of matter, namely atoms, molecules and clusters. The\\u000a instrumentation will be

  16. Recent progress on the Constellation-X spectroscopy x-ray telescope (SXT)

    Microsoft Academic Search

    Robert Petre; Stephen L. O'Dell; Scott M. Owens; William A. Podgorski; Jeffrey W. Stewart; Timo T. Saha; William W. Zhang

    2004-01-01

    The Constellation X-ray Observatory consists of four identical spacecraft, each carrying a complement of high sensitivity X-ray instrumentation. At the heart of each is the grazing incidence mirror of the Spectroscopy X-ray Telescope (SXT). This mirror has a diameter of 1.6 m, a focal length of 10 m, mass not exceeding ~650 kg. The required angular resolution is 15 arc

  17. Constellation-X Spectroscopy X-Ray Telescope Segmented Optic Assembly and Alignment Implementation

    E-print Network

    Constellation-X Spectroscopy X-Ray Telescope Segmented Optic Assembly and Alignment Implementation. ABSTRACT The Constellation-X mission will perform X-Ray science with improvements in energy resolution and effective area over its predecessor missions. The primary instrument on each of the four Constellation

  18. The UHURU X-ray instrument.

    NASA Technical Reports Server (NTRS)

    Jagoda, N.; Austin, G.; Mickiewicz, S.; Goddard, R.

    1972-01-01

    On Dec. 12, 1970, the UHURU X-ray observatory was launched into equatorial orbit with the prime mission of conducting an all-sky survey of astronomical X-ray sources with intensities of 0.00005 Sco-X1 or greater. The X-ray detection system contains 12 gas-filled proportional counters, 6 behind each collimator. The aspect system is discussed together with the structure, the pulse height analyzer, the command system, the calibration system, and the power distribution system. Pulse shape discrimination circuits used on UHURU use the same technique that was used on the system originally developed for large area proportional counters described by Gorenstein and Mickiewicz (1968).

  19. X-ray spectroscopy of NGC 5548

    E-print Network

    Kaastra, J S; Raassen, A J J; Van der Meer, R L J; Brinkman, A C; Liedahl, D A; Behar, E; De Rosa, A

    2002-01-01

    We analyze the high-resolution X-ray spectrum of the Seyfert 1 galaxy NGC 5548, for the full 0.1-10 keV band, using improved calibration results of the Chandra-LETGS instrument. The warm absorber consists of at least three ionization components, namely one with a low, medium and high ionization parameter. The X-ray absorbing material, from an outflowing wind, covers the full range of velocity components found from UV absorption lines. The presence of redshifted emission components for the strongest blue-shifted resonance absorption lines indicate that the absorber is located at a distance larger than the edge of the accretion disk. We derive an upper limit to the edge of the accretion disk of 1 light year. Absorption lines from ions of at least ten chemical elements have been detected, and in general for these elements there are no strong deviations from solar abundances. The narrow emission lines from the O VII and Ne IX forbidden and intercombination lines probably originate from much larger distances to th...

  20. X-ray spectroscopy of NGC 5548

    E-print Network

    J. S. Kaastra; K. C. Steenbrugge; A. J. J. Raassen; R. L. J. van der Meer; A. C. Brinkman; D. A. Liedahl; E. Behar; A. de Rosa

    2002-02-26

    We analyze the high-resolution X-ray spectrum of the Seyfert 1 galaxy NGC 5548, for the full 0.1-10 keV band, using improved calibration results of the Chandra-LETGS instrument. The warm absorber consists of at least three ionization components, namely one with a low, medium and high ionization parameter. The X-ray absorbing material, from an outflowing wind, covers the full range of velocity components found from UV absorption lines. The presence of redshifted emission components for the strongest blue-shifted resonance absorption lines indicate that the absorber is located at a distance larger than the edge of the accretion disk. We derive an upper limit to the edge of the accretion disk of 1 light year. Absorption lines from ions of at least ten chemical elements have been detected, and in general for these elements there are no strong deviations from solar abundances. The narrow emission lines from the O VII and Ne IX forbidden and intercombination lines probably originate from much larger distances to the black hole. We find evidence for weak relativistically broadened oxygen and nitrogen emission lines from the inner parts of the accretion disk, but at a much smaller flux level than those observed in some other active galactic nuclei. In addition, there is a broad, non-relativistic C VI Ly alpha emission line that is consistent with emission lines from the inner part of the optical/UV broad line region.

  1. Surface-sensitive X-ray diffraction methods: physics, applications and related X-ray and SR instrumentation

    Microsoft Academic Search

    M. V. Kovalchuk; A. Yu Kazimirov; S. I. Zheludeva

    1995-01-01

    The review of the surface-sensitive X-ray diffraction methods including surface X-ray diffraction and X-ray standing wave method is presented. The discussion is illustrated by numerous examples of applications of these methods in different fields of science and technology. Instrumentation and X-ray optics for realization of these methods with laboratory X-ray sources and synchrotron radiation is discussed.

  2. Surface-sensitive X-ray diffraction methods: Physics, applications and related X-ray and SR instrumentation

    NASA Astrophysics Data System (ADS)

    Kovalchuk, M. V.; Kazimirov, A. Yu.; Zheludeva, S. I.

    1995-08-01

    The review of the surface-sensitive X-ray diffraction methods including surface X-ray diffraction and X-ray standing wave method is presented. The discussion is illustrated by numerous examples of applications of these methods in different fields of science and technology. Instrumentation and X-ray optics for realization of these methods with laboratory X-ray sources and synchrotron radiation is discussed.

  3. An X-ray diffraction and X-ray absorption spectroscopy joint study of neuroglobin

    Microsoft Academic Search

    Alessandro Arcovito; Tommaso Moschetti; Paola D’Angelo; Giordano Mancini; Beatrice Vallone; Maurizio Brunori; Stefano Della Longa

    2008-01-01

    Neuroglobin (Ngb) is a member of the globin family expressed in the vertebrate brain, involved in neuroprotection. A combined approach of X-ray diffraction (XRD) on single crystal and X-ray absorption spectroscopy (XAS) in solution, allows to determine the oxidation state and the structure of the Fe–heme both in the bis-histidine and the CO-bound (NgbCO) states. The overall data demonstrate that

  4. Soft X-ray induced damage in PVA-based membranes in water environment monitored by X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Tzvetkov, George; Späth, Andreas; Fink, Rainer H.

    2014-10-01

    The effect of synchrotron X-ray flux in a soft X-ray scanning-transmission microspectroscope (STXM) instrument on the chemical structure of air-filled poly(vinyl alcohol) (PVA) based microbubbles and their stabilizing shell has been examined. Prolonged soft X-ray illumination of the particles in aqueous suspension leads to the breaking of the microbubbles' protective polymer shell and substantial chemical changes. The latter were clarified via a micro-spot C K-edge near-edge X-ray absorption fine structure (NEXAFS) spectroscopy with further respect to the absorbed X-ray doses. Our results revealed a continuous degradation of the PVA network associated with formation of carbonyl- and carboxyl-containing species as well as an increased content of unsaturated bonds. The observed effects must be taken into account in studies of micro- and nanostructured polymer materials utilizing X-rays.

  5. Instrument and method for X-ray diffraction, fluorescence, and crystal texture analysis without sample preparation

    NASA Technical Reports Server (NTRS)

    Gendreau, Keith (Inventor); Martins, Jose Vanderlei (Inventor); Arzoumanian, Zaven (Inventor)

    2010-01-01

    An X-ray diffraction and X-ray fluorescence instrument for analyzing samples having no sample preparation includes a X-ray source configured to output a collimated X-ray beam comprising a continuum spectrum of X-rays to a predetermined coordinate and a photon-counting X-ray imaging spectrometer disposed to receive X-rays output from an unprepared sample disposed at the predetermined coordinate upon exposure of the unprepared sample to the collimated X-ray beam. The X-ray source and the photon-counting X-ray imaging spectrometer are arranged in a reflection geometry relative to the predetermined coordinate.

  6. Synchrotron radiation, soft-X-ray spectroscopy andnanomaterials

    SciTech Connect

    Guo, Jinghua

    2004-09-13

    Both synchrotron radiation based soft-X-ray absorption spectroscopy (XAS) and resonant soft-X-ray emission spectroscopy (XES) on a variety of nano-structured systems has yielded characteristic fingerprints. With high-resolution monochromatized synchrotron radiation excitation, resonant inelastic X-ray scattering (RIXS) has emerged as a new source of information about electronic structure and excitation dynamics of nanomaterials. The selectivity of the excitation, in terms of energy and polarization, has also facilitated studies of emission anisotropy. Various features observed in resonant emission spectra have been identified and studied.

  7. Crystals for astronomical X-ray spectroscopy

    NASA Technical Reports Server (NTRS)

    Burek, A.

    1976-01-01

    Crystal spectrometric properties and the factors that affect their measurement are discussed. Theoretical and experimental results on KAP are summarized and theoretical results based on the dynamical theory of X-ray diffraction are given for the acid phthalates as well as for the commonly used planes of ADP, PET and EDDT. Anomalous dispersion is found to be important for understanding the details of crystal Bragg reflection properties at long X-ray wavelengths and some important effects are pointed out. The theory of anomalous dispersion is applied to explain the anomalous reflectivity exhibited by KAP at 23.3 A.

  8. Tokamak Spectroscopy for X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Fournier, Kevin B.; Finkenthal, M.; Pacella, D.; May, M. J.; Soukhanovskii, V.; Mattioli, M.; Leigheb, M.; Rice, J. E.

    2000-01-01

    This paper presents the measured x-ray and Extreme Ultraviolet (XUV) spectra of three astrophysically abundant elements (Fe, Ca and Ne) from three different tokamak plasmas. In every case, each spectrum touches on an issue of atomic physics that is important for simulation codes to be used in the analysis of high spectral resolution data from current and future x-ray telescopes. The utility of the tokamak as a laboratory test bed for astrophysical data is demonstrated. Simple models generated with the HULLAC suite of codes demonstrate how the atomic physics issues studied can affect the interpretation of astrophysical data.

  9. The Advanced X-ray Spectroscopy and Imaging Observatory (AXSIO)

    NASA Technical Reports Server (NTRS)

    White, Nicholas E.; Bookbinder, Jay; Petre, Robert; Smith, Randall; Ptak, Andrew; Tananbaum, Harvey; Garcia, Michael

    2012-01-01

    Following recommendations from the 2010 "New Worlds, New Horizons" (NWNH) report, the Advanced X-ray Spectroscopy and Imaging Observatory (AXSIO) concept streamlines the International X-ray Observatory (IXO) mission to concentrate on the science objectives that are enabled by high-resolution spectroscopic capabilities. AXSIO will trace orbits close to the event horizon of black holes, measure black hole spin for tens of supermassive black holes (SMBH), use spectroscopy to characterize outflows and the environment of AGN during their peak activity, observe 5MBH out to redshift z=6, map bulk motions and turbulence in galaxy clusters, find the missing baryons in the cosmic web using background quasars, and observe the process of cosmic feedback where black holes and supernovae inject energy on galactic and intergalactic scales. These measurements are enabled by a 0.9 sq m collecting area at 1.25 keV, a micro calorimeter array providing high-resolution spectroscopic imaging and a deployable high efficiency grating spectrometer. AXSIO delivers a 30-fold increase in effective area for high resolution spectroscopy. The key simplifications are guided by recommendations in the NWNH panel report include a reduction in focal length from 20m to 10m, eliminating the extendable optical bench, and a reduction in the instrument complement from six to two, avoiding a movable instrument platform. A focus on spectroscopic science allows the spatial resolution requirement to be relaxed to 10 arc sec (with a 5 arc sec goal). These simplifications decrease the total mission cost to under the $2B cost to NASA recommended by NWNH. AXSIO will be available to the entire astronomical community with observing allocations based on peer-review.

  10. The Advanced X-ray Spectroscopy and Imaging Observatory (AXSIO)

    NASA Astrophysics Data System (ADS)

    White, Nicholas E.; Bookbinder, Jay; Petre, Robert; Smith, Randall; Ptak, Andrew; Tananbaum, Harvey; Bregman, Joel; Garcia, Michael; Zhang, W.; Kelley, R.; Kilbourne, C.; Bandler, S.

    2012-09-01

    Following recommendations from the 2010 "New Worlds, New Horizons" (NWNH) report, the Advanced X-ray Spectroscopy and Imaging Observatory (AXSIO) concept streamlines the International X-ray Observatory (IXO) mission to concentrate on the science objectives that are enabled by high-resolution spectroscopic capabilities. AXSIO will trace orbits close to the event horizon of black holes, measure black hole spin for tens of supermassive black holes (SMBH), use spectroscopy to characterize outflows and the environment of AGN during their peak activity, observe SMBH out to redshift z=6, map bulk motions and turbulence in galaxy clusters, find the missing baryons in the cosmic web using background quasars, and observe the process of cosmic feedback where black holes and supernovae inject energy on galactic and intergalactic scales. These measurements are enabled by a 0.9 sq m collecting area at 1.25 keV, a microcalorimeter array providing high-resolution spectroscopic imaging and a deployable high efficiency grating spectrometer. AXSIO delivers a 30-fold increase in effective area for high-resolution spectroscopy. The key simplifications are guided by recommendations in the NWNH panel report include a reduction in focal length from 20m to 10m, eliminating the extendable optical bench, and a reduction in the instrument complement from six to two, avoiding a movable instrument platform. A focus on spectroscopic science allows the spatial resolution requirement to be relaxed to 10 arcsec (with a 5 arc sec goal). These simplifications decrease the total mission cost to under the $2B cost to NASA recommended by NWNH. AXSIO will be available to the entire astronomical community with observing allocations based on peer- review.

  11. X-ray spectroscopy of manganese clusters

    SciTech Connect

    Grush, M.M. [Univ. of California, Davis, CA (United States). Dept. of Applied Science; [Lawrence Berkeley National Lab., CA (United States). Energy and Environment Div.

    1996-06-01

    Much of this thesis represents the groundwork necessary in order to probe Mn clusters more productively than with conventional Mn K-edge XAS and is presented in Part 1. Part 2 contains the application of x-ray techniques to Mn metalloproteins and includes a prognosis at the end of each chapter. Individual Mn oxidation states are more readily distinguishable in Mn L-edge spectra. An empirical mixed valence simulation routine for determining the average Mn oxidation state has been developed. The first Mn L-edge spectra of a metalloprotein were measured and interpreted. The energy of Mn K{beta} emission is strongly correlated with average Mn oxidation state. K{beta} results support oxidation states of Mn(III){sub 2}(IV){sub 2} for the S{sub 1} state of Photosystem II chemical chemically reduced preparations contain predominantly Mn(II). A strength and limitation of XAS is that it probes all of the species of a particular element in a sample. It would often be advantageous to selectively probe different forms of the same element. The first demonstration that chemical shifts in x-ray fluorescence energies can be used to obtain oxidation state-selective x-ray absorption spectra is presented. Spin-dependent spectra can also be used to obtain a more simplified picture of local structure. The first spin-polarized extended x-ray absorption fine structure using Mn K{beta} fluorescence detection is shown.

  12. X-Ray Spectroscopy of Gold Nanoparticles

    NASA Astrophysics Data System (ADS)

    Nahar, Sultana N.; Montenegro, M.; Pradhan, A. K.; Pitzer, R.

    2009-06-01

    Inner shell transitions, such as 1s-2p, in heavy elements can absorb or produce hard X-rays, and hence are widely used in nanoparticles. Bio-medical research for cancer treatment has been using heavy element nanoparticles, embeded in malignant tumor, for efficient absorption of irradiated X-rays and leading emission of hard X-rays and energetic electrons to kill the surrounding cells. Ejection of a 1s electron during ionization of the element by absorption of a X-ray photon initiates the Auger cascades of emission of photons and electrons. We have investigated gold nanoparticles for the optimal energy range, below the K-edge (1s) ionization threshold, that corresponds to resonant absorption of X-rays with large attenuation coefficients, orders of magnitude higher over the background as well as to that at K-edge threshold. We applied these attenuation coefficients in Monte Carlo simulation to study the intensities of emission of photons and electrons by Auger cascades. The numerical experiments were carried out in a phantom of water cube with a thin layer, 0.1mm/g, of gold nanoparticles 10 cm inside from the surface using the well-known code Geant4. We will present results on photon and electron emission spectra from passing monochromatic X-ray beams at 67 keV, which is the resonant energy for resonant K_{?} lines, at 82 keV, the K-shell ionization threshold, and at 2 MeV where the resonant effect is non-existent. Our findings show a high peak in the gold nanoparticle absorption curve indicating complete absorption of radiation within the gold layer. The photon and electron emission spectra show resonant features. Acknowledgement: Partially supported by a Large Interdisciplinary Grant award of the Ohio State University and NASA APRA program (SNN). The computational work was carried out on the Cray X1 and Itanium 4 cluster at the Ohio Supercomputer Center, Columbus Ohio. "Resonant X-ray Irradiation of High-Z Nanoparticles For Cancer Theranostics" (refereed presentation), A Pradhan, S Nahar, M Montenegro, C Sur, M Mrozik, R Pitzer, E Silver, Y Yu, 50th Annual Meeting of the American Association of Physicists in Medicine in Houston, Texas, July 27 - 31, 2008

  13. The soft x-ray materials research (SXR) instrument at the Linac Coherent Light Source

    NASA Astrophysics Data System (ADS)

    Turner, Joshua J.; Krupin, Oleg; Schlotter, William

    2011-03-01

    The soft x-ray materials science research (SXR) instrument completed commissioning in June 2010 and began experimental user operations shortly afterwards. This instrument delivers intense, ultra-short soft x-ray pulses from the Linac Coherent Light Source, the free-electron laser at the SLAC National Accelerator Laboratory. These are fully coherent and can contain up to 1013 photons per pulse (or about 3 mJ per pulse) with bunch lengths from 300 femtoseconds down to sub-10 femtoseconds. The instrument includes a monochromator whose energy range spans energies from 480 eV - 2000 eV and a Kirkpatrick-Baez mirror system to create a focal spot of a few microns in diameter. The SXR instrument has a diverse set of end stations available to conduct a large variety of experimental techniques such as coherent imaging, resonant x-ray diffraction, photoelectron spectroscopy, and x-ray emission and/or absorption. First studies include fields spanning liquid femtosecond chemistry and time-resolved resonant inelastic x-ray scattering to ordering in solids and ultrafast magnetization. An overview of the instrument and its capabilities will be given.

  14. The High Throughput X-ray Spectroscopy (HTXS) Mission

    NASA Astrophysics Data System (ADS)

    White, N. E.; Tananbaum, H.; Kahn, S. M.

    1997-01-01

    The HTXS mission concept combines large effective area (approximately 15,000 sq cm at 1 keV), high spectral resolution (E/Delta(E) approximately 300-3000), and broad energy bandpass (0.25-40 keV and possibly up to 100 keV) by using replicated optics together with a complement of spectroscopic instrumentation including reflection gratings readout by charge-coupled device detectors (CCDs), quantum micro-calorimeters, and cadmium zinc telluride (CZT) or comparable high energy detectors. An essential feature of this concept involves minimization of cost (approximately 350M for development and approximately 500-600M including launches) and risk by building six identical modest satellites to achieve the large area. Current mission and technology studies are targeted towards a new start in the 2002 timeframe, with first launch around 2005-2006. The HTXS mission represents a major advance, providing as much as a factor of 100 increase in sensitivity over currently planned high resolution X ray spectroscopy missions. HTXS will mark the start of a new era when high quality X ray spectra will be obtained for all classes of X ray sources, over a wide range of luminosity and distance. With its increased capabilities, HTXS will address many fundamental astrophysics questions such as the origin and distribution of the elements from carbon to zinc, the formation and evolution of clusters of galaxies, the validity of general relativity in the strong gravity limit, the evolution of supermassive black holes in active galactic nuclei, the details of supernova explosions and their aftermath, and the mechanisms involved in the heating of stellar coronae and driving of stellar winds.

  15. Chemical Shifts in X-ray and Photo-Electron Spectroscopy: A Historical review

    E-print Network

    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

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

    SciTech Connect

    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.

  17. X-ray diffraction assisted spectroscopy of Rydberg states

    SciTech Connect

    Kirrander, Adam [ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States)

    2012-10-21

    X-ray diffraction combined with conventional spectroscopy could provide a powerful means to characterize electronically excited atoms and molecules. We demonstrate theoretically how x-ray diffraction from laser excited atoms can be used to determine electronic structure, including angular momentum composition, principal quantum numbers, and channel populations. A theoretical formalism appropriate for highly excited atoms, and easily extended to molecules, is presented together with numerical results for Xe and H atoms.

  18. Small pixel CZT detector for hard X-ray spectroscopy

    Microsoft Academic Search

    Matthew David Wilson; Robert Cernik; Henry Chen; Conny Hansson; Kris Iniewski; Lawrence L. Jones; Paul Seller; Matthew C. Veale

    2011-01-01

    A new small pixel cadmium zinc telluride (CZT) detector has been developed for hard X-ray spectroscopy. The X-ray performance of four detectors is presented and the detectors are analysed in terms of the energy resolution of each pixel. The detectors were made from CZT crystals grown by the travelling heater method (THM) bonded to a 20×20 application specific integrated circuit

  19. New focusing multilayer structures for X-ray plasma spectroscopy

    SciTech Connect

    Bibishkin, M S; Luchin, V I; Salashchenko, N N; Chernov, V V; Chkhalo, N I [Institute for Physics of Microstructures, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation); Kazakov, E D; Shevelko, A P [P.N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    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)

  20. X-ray absorption spectroscopy of bacterial sulfur globules

    Microsoft Academic Search

    Graham N

    2002-01-01

    Sulfur K-edge X-ray absorption spectroscopy is a powerful in situ probe of sulfur biochemistry in intact cells and tissues. Under favorable circumstances the technique can provide quantitative information on the chemical identify of the sulfur species that are present in a sample. Prange et al. have recently reported an X-ray absorption spectroscopic study of bacterial sulfur storage globules. Unfortunately there

  1. X-ray spectroscopy using accel-decel at ATLAS

    NASA Astrophysics Data System (ADS)

    Dunford, R. W.; Pardo, R. C.; Raphaelian, M. L. A.; Berry, H. G.; Deslattes, R. D.

    1988-05-01

    We have demonstrated the capability of the Argonne tandem-linac (ATLAS) for producing decelerated beams for precision X-ray spectroscopy. Beams of 40Ca 18,19,20+ were produced by foil stripping at 205 MeV followed by deceleration to 105 and 129 MeV. The ions were directed onto a gas target where X-rays emitted following electron pickup were observed with a Si(Li)detector.

  2. Sapphire analyzers for high-resolution x-ray spectroscopy.

    SciTech Connect

    Yavas, H.; Alp, E.; Sinn, H.; Alatas, A.; Said, A.; Shvydko, Y.; Toellner, T.; Khachatryan, R.; Billinge, S.; Hasan, Z.; Sturhahn, W.; Michigan State Univ.; Princeton Univ.; DESY

    2007-11-11

    We present a sapphire (Al{sub 2}O{sub 3}) analyzer for high-resolution X-ray spectroscopy with 31-meV energy resolution. The analyzer is designed for resonant inelastic X-ray scattering (RIXS) measurements at the CuK{sub a} absorption edge near 8990 eV. The performance of the analyzer is demonstrated by measuring phonon excitations in beryllium because of its known dynamical structure and high counting rates.

  3. X-ray Spectroscopy of Cataclysmic Variables

    E-print Network

    Koji Mukai

    2001-12-03

    In cataclysmic variables (CVs), accretion onto white dwarfs produces high temperature, high density plasmas. They cool down from kT~10 keV via bremsstrahlung continuum and K and L shell line emissions. The small volume around white dwarfs means that the plasma densities are much higher than in, e.g., stellar coronae, probably beyond the range well-described by existing models. I will describe potential diagnostics of the temperatures, the densities, and the optical depths of X-ray emitting plasmas in CVs, and present the recent Chandra grating spectra of the magnetic CV V1223 Sgr as an example.

  4. Advanced X-ray Astrophysics Facility (AXAF) instrumentation

    NASA Technical Reports Server (NTRS)

    Winkler, C. E.; Dailey, C. C.; Cumings, N. P.

    1986-01-01

    The instrumentation planned for the Advanced X-ray Astrophysics Facility (AXAF), a space-based observation platform for the 1990s, is described. The AXAF will feature a grazing incidence telescope at the end of the observatory and four independently selected instruments at the other end, including: a CCD imaging spectrometer; a Bragg crystal spectrometer; and two transmission grating spectrometers located directly behind the telescope to detect first order spectral images. The instruments are currently in the definition phase to be followed by design and development starting in the late 1980s. A detailed schematic diagram of the Bragg crystal imaging spectrometer is provided.

  5. Atomic Multiplets in X-ray Spectroscopies of Solids

    NASA Astrophysics Data System (ADS)

    Delley, Bernard; Uldry, Anne-Christine

    2013-03-01

    The electronic structures of compounds involving open d- and f- shell are studied frequently by X-ray and electron spectroscopies. For a better understanding of the multiplets arising in spectra involving one or more open shells, we have developed recently an easy to use program multiX,[2] which is available to download.[3] This first step allows the inclusion of the crystal environment as a crystal field entered simply as positions and charges of a cluster of atoms around the core hole site. This often gives valuable insights in the case of x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray spectroscopy (RIXS) measurements. However, in many cases it is desirable to allow for hybridization of the open shell electrons with the orbitals of neighbor atoms. This requires dealing with a significantly larger active Hilbert space. This is addressed with our recent Lanczos-based procedure to calculate spectra. First results will be discussed. The electronic structures of compounds involving open d- and f- shell are studied frequently by X-ray and electron spectroscopies. For a better understanding of the multiplets arising in spectra involving one or more open shells, we have developed recently an easy to use program multiX,[2] which is available to download.[3] This first step allows the inclusion of the crystal environment as a crystal field entered simply as positions and charges of a cluster of atoms around the core hole site. This often gives valuable insights in the case of x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray spectroscopy (RIXS) measurements. However, in many cases it is desirable to allow for hybridization of the open shell electrons with the orbitals of neighbor atoms. This requires dealing with a significantly larger active Hilbert space. This is addressed with our recent Lanczos-based procedure to calculate spectra. First results will be discussed. Swiss SNF grant 200021-129970 is gratefully acknowledged.

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

    NASA Astrophysics Data System (ADS)

    Katayama, Tetsuo; Inubushi, Yuichi; Obara, Yuki; Sato, Takahiro; Togashi, Tadashi; Tono, Kensuke; Hatsui, Takaki; Kameshima, Takashi; Bhattacharya, Atanu; Ogi, Yoshihiro; Kurahashi, Naoya; Misawa, Kazuhiko; Suzuki, Toshinori; Yabashi, Makina

    2013-09-01

    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 × 10-3), 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 × 10-3, 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.

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

    SciTech Connect

    Katayama, Tetsuo; Togashi, Tadashi; Tono, Kensuke; Kameshima, Takashi [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)] [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Inubushi, Yuichi; Sato, Takahiro; Hatsui, Takaki; Yabashi, Makina [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)] [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Obara, Yuki; Misawa, Kazuhiko [Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan)] [Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Bhattacharya, Atanu; Kurahashi, Naoya [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan)] [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Ogi, Yoshihiro [Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198 (Japan)] [Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198 (Japan); Suzuki, Toshinori [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan) [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198 (Japan)

    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.

  8. Diamond Photodetectors for X-Ray Absorption Spectroscopy Applications

    NASA Astrophysics Data System (ADS)

    Pace, Emanuele; De Sio, Antonio; Pan, Zhiyun; Wu, Ziyu; Marcelli, Augusto

    2010-06-01

    Synchrotron radiation (SR) is a fundamental tool for X-ray research. In particular, X-ray absorption spectroscopy (XAS) accesses information as electronic properties, local structure or chemical-physical state in condensed-matter studies. Ionization chambers (ICs) are the most widely used XAS detectors for transmission measurements because of their reliability, high linearity and good stability. Recently, solid-state detectors have been considered and Si p-i-n has been applied to high fluxes (1011 ph/s), where the linearity of ICs is no longer guaranteed. Silicon photodiodes exhibit an extremely linear response in at least 5 decades but show diffraction peaks. Diamond is an ideal substrate to produce radiation-hard, low dark current (<1 pA/cm2), visible-blind and fast-response X-ray detectors with a high S/N ratio. Diamond detectors were tested as SR monitor capable to withstand the high photon flux density of the 3rd generation SR sources. Being the lowest X-ray-absorbing solid-state dielectric material, diamond maximizes the flux through thin self-standing devices with minimal spectral effect down to the soft x-ray range. We will present results of X-ray tests of photoconductors based on different diamond substrates. The results will be compared to standard ICs for XAS applications in terms of spectral quality, noise and linearity in the 4-13 keV energy range.

  9. Effect of X-ray flux on polytetrafluoroethylene in X-ray photoelectron spectroscopy

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.; Pepper, S. V.

    1982-01-01

    The effect of the X-ray flux in X-ray photoelectron spectroscopy (STAT) on the constitution of the polytetrafluoroethylene (PTFE) surface has been examined. The radiation dose rate for our specimen was about 10 to the 7th rad/s. The structure, magnitude and binding energy of the C(1s) and F(1s) features of the XPS spectrum and the mass spectrum of gaseous species evolved during irradiation are observed. The strong time dependence of these signals over a period of several hours indicated that the surface constitution of PTFE is greatly affected by this level of radiation dose. The results are consistent with the development of a heavily cross-linked or branched structure in the PTFE surface region and the evolution of short chain fragments into the gas phase.

  10. X-ray Photoelectron Spectroscopy Database (Version 4.1)

    National Institute of Standards and Technology Data Gateway

    SRD 20 X-ray Photoelectron Spectroscopy Database (Version 4.1) (Web, free access)   The NIST XPS Database gives access to energies of many photoelectron and Auger-electron spectral lines. The database contains over 22,000 line positions, chemical shifts, doublet splittings, and energy separations of photoelectron and Auger-electron lines.

  11. Transient x-ray absorption spectroscopy of hydrated halogen atom

    E-print Network

    Elles, Christopher G.; Shkrob, Ilya A.; Crowell, Robert A.; Arms, Dohn A.; Landahl, Eric C.

    2008-02-11

    Time-resolved x-ray absorption spectroscopy has been used to observe the transient species generated by one-photon detachment of an electron from aqueous bromide. The K-edge spectrum of the short-lived Br(0) atom exhibits a resonant 1s-4p transition...

  12. Electron yield X-ray absorption spectroscopy at atmospheric pressure

    Microsoft Academic Search

    G. Tourillon; E. Dartyge; A. Fontaine; M. Lemonnier; F. Bartol

    1987-01-01

    The electron yield at atmospheric pressure for X-ray absorption spectroscopy is a new technique able to study the very top surface of thick samples in real environments. A combined detector has been designed at LURE which yields EXAFS spectra in transmission, electron and fluorescence modes. A variable probed thickness is obtained, depending on the polarization. With a positively biased collector

  13. A rocket borne instrument for the study of soft X-ray emission from cosmic X-ray sources

    NASA Technical Reports Server (NTRS)

    Agrawal, P. C.; Moore, W. E.; Garmire, G. P.

    1974-01-01

    Details about a rocket-borne instrument designed for studying the various characteristics of soft X-ray emission from cosmic X-ray sources in the energy range of 0.2 to 3 keV are presented. The X-ray detector consists of a bank of four multilayer, wall-less proportional counters, each with an area of 400 sq cm. The detectors are covered by windows of 1.4-micron polypropylene and are maintained at a constant pressure in flight using a gas control system. Two of the detectors are equipped with 0.4- by 10-deg collimators for mapping the spatial distribution of soft X-rays from extended X-ray sources. A pair of balanced filters consisting of oxygen and CF4 are used for detecting oxygen emission lines.

  14. Improved x-ray spectroscopy with room temperature CZT detectors

    NASA Astrophysics Data System (ADS)

    Fritz, Shannon G.; Shikhaliev, Polad M.; Matthews, Kenneth L., II

    2011-09-01

    Compact, room temperature x-ray spectroscopy detectors are of interest in many areas including diagnostic x-ray imaging, radiation protection and dosimetry. Room temperature cadmium zinc telluride (CZT) semiconductor detectors are promising candidates for these applications. One of the major problems for CZT detectors is low-energy tailing of the energy spectrum due to hole trapping. Spectral post-correction methods to correct the tailing effect do not work well for a number of reasons; thus it is advisable to eliminate the hole trapping effect in CZT using physical methods rather than correcting an already deteriorated energy spectrum. One method is using a CZT detector with an electrode configuration which modifies the electric field in the CZT volume to decrease low-energy tailing. Another method is to irradiate the CZT surface at a tilted angle, which modifies depth of interaction to decrease low-energy tailing. Neither method alone, however, eliminates the tailing effect. In this work, we have investigated the combination of modified electric field and tilted angle irradiation in a single detector to further decrease spectral tailing. A planar CZT detector with 10 × 10 × 3 mm3 size and CZT detector with 5 × 5 × 5 mm3 size and cap-shaped electrode were used in this study. The cap-shaped electrode (referred to as CAPture technology) modifies the electric field distribution in the CZT volume and decreases the spectral tailing effect. The detectors were investigated at 90° (normal) and 30° (tilted angle) irradiation modes. Two isotope sources with 59.6 and 122 keV photon energies were used for gamma-ray spectroscopy experiments. X-ray spectroscopy was performed using collimated beams at 60, 80 and 120 kVp tube voltages, in both normal and tilted angle irradiation. Measured x-ray spectra were corrected for K x-ray escape fractions that were calculated using Monte Carlo methods. The x-ray spectra measured with tilted angle CAPture detector at 60, 80 and 120 kVp tube voltages were compared to corresponding theoretical spectra. The low-energy tailing was nearly completely eliminated from 59.6 and 122 keV isotope spectra, and 60, 80 and 120 kVp x-ray spectra, when CAPture detector was used with 30° tilted angle irradiation. It is concluded that using a CZT detector with modified electric field in tilted angle configuration resolves problem of the tailing effect in CZT detectors, opening promising possibilities in gamma-ray and x-ray spectroscopy applications.

  15. Rolf Mewe: a career devoted to X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Kaastra, Jelle S.; Mewe, Rolf

    2005-06-01

    An overview of the life and work of Rolf Mewe (1935-2004) as an X-ray spectroscopist is given. He was one of the pioneers in the field of X-ray spectroscopy. His work illustrates nicely how this field developed from the early days up to the present high-resolution era. His plasma emission codes, developed by him and collaborators over several decades, is one of the most widely used. His thorough knowledge of the field, as well as his ability and enthousiasm to cooperate with many colleagues, made his career a succes. He will be missed by all of us for his work and personality.

  16. 28 CFR 552.13 - X-ray, major instrument, fluoroscope, or surgical intrusion.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false X-ray, major instrument, fluoroscope...Inmates, and Inmate Work Areas § 552.13 X-ray, major instrument, fluoroscope...institution physician may authorize use of an X-ray for medical reasons and only...

  17. 28 CFR 552.13 - X-ray, major instrument, fluoroscope, or surgical intrusion.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false X-ray, major instrument, fluoroscope...Inmates, and Inmate Work Areas § 552.13 X-ray, major instrument, fluoroscope...institution physician may authorize use of an X-ray for medical reasons and only...

  18. 28 CFR 552.13 - X-ray, major instrument, fluoroscope, or surgical intrusion.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false X-ray, major instrument, fluoroscope...Inmates, and Inmate Work Areas § 552.13 X-ray, major instrument, fluoroscope...institution physician may authorize use of an X-ray for medical reasons and only...

  19. 28 CFR 552.13 - X-ray, major instrument, fluoroscope, or surgical intrusion.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false X-ray, major instrument, fluoroscope...Inmates, and Inmate Work Areas § 552.13 X-ray, major instrument, fluoroscope...institution physician may authorize use of an X-ray for medical reasons and only...

  20. 28 CFR 552.13 - X-ray, major instrument, fluoroscope, or surgical intrusion.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false X-ray, major instrument, fluoroscope...Inmates, and Inmate Work Areas § 552.13 X-ray, major instrument, fluoroscope...institution physician may authorize use of an X-ray for medical reasons and only...

  1. Advanced X-ray Astrophysics Facility (AXAF) science instruments

    NASA Technical Reports Server (NTRS)

    Winkler, Carl E.; Dailey, Carroll C.; Cumings, Nesbitt P.

    1991-01-01

    The overall AXAF program is summarized, with particular emphasis given to its science instruments. The science objectives established for AXAF are to determine the nature of celestial objects, from normal stars to quasars, to elucidate the nature of the physical processes which take place in and between astronomical objects, and to shed light on the history and evolution of the universe. Attention is given to the AXAF CCD imaging spectrometer, which is to provide spectrally and temporally resolved imaging, or, in conjunction with transmission grating, high-resolution dispersed spectral images of celestial sources. A high-resolution camera, an X-ray spectrometer, and the Bragg Crystal Spectrometer are also discussed.

  2. High-resolution X-ray spectroscopy of Theta Car

    E-print Network

    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.

  3. Crystal optics for precision x-ray spectroscopy on highly charged ions—conception and proof

    NASA Astrophysics Data System (ADS)

    Beyer, H. F.; Gassner, T.; Trassinelli, M.; Heß, R.; Spillmann, U.; Bana?, D.; Blumenhagen, K.-H.; Bosch, F.; Brandau, C.; Chen, W.; Dimopoulou, Chr; Förster, E.; Grisenti, R. E.; Gumberidze, A.; Hagmann, S.; Hillenbrand, P.-M.; Indelicato, P.; Jagodzinski, P.; Kämpfer, T.; Kozhuharov, Chr; Lestinsky, M.; Liesen, D.; Litvinov, Yu A.; Loetzsch, R.; Manil, B.; Märtin, R.; Nolden, F.; Petridis, N.; Sanjari, M. S.; Schulze, K. S.; Schwemlein, M.; Simionovici, A.; Steck, M.; Stöhlker, Th; Szabo, C. I.; Trotsenko, S.; Uschmann, I.; Weber, G.; Wehrhan, O.; Winckler, N.; Winters, D. F. A.; Winters, N.; Ziegler, E.

    2015-07-01

    The experimental investigation of quantum-electrodydamic contributions to the binding energies of inner shells of highly charged heavy ions requires an accurate spectroscopy in the region of hard x-rays suitable at a limited source strength. For this purpose the focusing compensated asymmetric Laue crystal optics has been developed and a twin-spectrometer assembly has been built and commissioned at the experimental storage ring of the GSI Helmholtzzentrum Darmstadt. We characterize the crystal optics and demonstrate the usefulness of the instrumentation for accurate spectroscopy of both stationary and fast moving x-ray sources. The experimental procedures discussed here may also be applied for other spectroscopic studies where a transition from conventional germanium x-ray detectors to crystal spectrometers seems too demanding because of low source intensity.

  4. Ambient-Pressure X-ray Photoelectron Spectroscopy

    SciTech Connect

    Bluhm, Hendrik; Bluhm, Hendrik; Mun, Bongjin Simon; Salmeron, Miquel

    2008-04-01

    This workshop focused on the application of ambient pressure X-ray photoelectron spectroscopy (APXPS) to environmental science and catalysis. Pioneering work on APXPS was done in the early 1970's by Hans and Kai Siegbahn et al., who demonstrated that XPS can operate at pressures of up to 1 Torr. A new type of APXPS instrument that utilizes a differentially-pumped electrostatic lens system at the ALS in 2001 increased the pressure limit to above 5 Torr, which opened the door to XPS experiments on water and aqueous solutions at temperatures above the melting point, in equilibrium with the vapor pressure of water. The impact of APXPS on fields such as environmental and atmospheric science as well as heterogeneous catalysis is already visible in numerous high impact publications. Today several other synchrotron facilities around the world have already implemented beam lines for APXPS or planning to do so in the near future. The goal of this workshop (organized by Miquel Salmeron (Molecular Foundry, LBNL), B. Simon Mun (Advanced Light Source, LBNL) and Hendrik Bluhm (Chemical Sciences Division, LBNL)) was to bring together researchers interested in the technique, review its current progress, discuss scientific opportunities and desirable technical improvements as well as consider the consequences of the increased user demand on the existing beam lines and ways to expand the availability of time.

  5. Design and operation of a high pressure reaction cell for in situ X-ray absorption spectroscopy

    Microsoft Academic Search

    Simon R. Bare; Ning Yang; Shelly D. Kelly; George E. Mickelson; Frank S. Modica

    2007-01-01

    X-ray absorption spectroscopy measurements of catalytic reactions have been instrumental in advancing the understanding of catalytic processes. These measurements require an in situ catalysis reaction cell with unique properties. Here we describe the design and initial operation of an in situ\\/operando catalysis reaction cell for transmission X-ray absorption spectroscopy measurements. The cell is designed: to be an ideal catalytic reactor

  6. X-ray Spectroscopy of Seyfert 2 Galaxies

    NASA Astrophysics Data System (ADS)

    Kinkhabwala, A.; Sako, M.; Behar, E.; Paerels, F.; Kahn, S. M.; Brinkman, A. C.; Kaastra, J. S.; Liedahl, D. A.

    2001-05-01

    A new, unprecedented era in X-ray spectroscopy has been made possible by the recent launching of the XMM-Newton and Chandra satellites. X-ray spectra, roughly comparable in resolution to optical/UV spectra, have been taken for several Seyfert 2 galaxies, including the brightest one, NGC 1068. Despite the varying optical, UV, and IR spectra of these Seyfert 2, their X-ray spectra appear remarkably similar. Bright, narrow radiative recombination continua provide the ``smoking gun'' for relatively cool, recombining gas photoionized by the nuclear continuum. However, all spectra show deviations from the predicted spectrum of a purely recombining gas. These deviations could be due to significant photoexcitation or a separate, collisionally-driven gas component (e. g., shock-heated gas in starburst regions). The observed anomalous strength of the higher-order ionic transitions provides unambiguous evidence for photoexcitation, whereas iron L-shell transitions provide useful diagnostics for determining the amount of collisionally-driven gas. Given the ability for robust discrimination of emission mechanisms, X-ray spectroscopy is uniquely well suited for probing the possible connection between Active Galactic Nucleus activity and star formation. A. K. would like to acknowledge support from an NSF fellowship.

  7. Theoretical aspects of resonant X-ray emission spectroscopy

    Microsoft Academic Search

    A. Kotani

    2004-01-01

    We report recent theoretical topics for resonant X-ray emission spectroscopy (RXES) in d and f electron systems: (1) RXES in high Tc cuprates, (2) effects of electric quadrupole excitation, and (3) magnetic circular dichroism (MCD) in RXES for ferromagnetic systems. In high Tc cuprates, RXES with Cu 1s excitation detects a 6eV charge transfer excitation whose intensity is affected by

  8. Probing deeper by hard x-ray photoelectron spectroscopy

    SciTech Connect

    Risterucci, P.; Renault, O., E-mail: olivier.renault@cea.fr; Martinez, E.; Delaye, V. [CEA, LETI, MINATEC Campus, 38054 Grenoble Cedex 09 (France); Detlefs, B. [CEA, LETI, MINATEC Campus, 38054 Grenoble Cedex 09 (France); European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble (France); Zegenhagen, J. [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, F-38043 Grenoble (France); Gaumer, C. [STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles (France); Grenet, G. [Institut des Nanotechnologies de Lyon (INL), UMR CNRS 5270, Ecole Centrale de Lyon, 36, avenue Guy de Collongue 69 134 Ecully Cedex (France); Tougaard, S. [Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M (Denmark)

    2014-02-03

    We report an hard x-ray photoelectron spectroscopy method combining high excitation energy (15?keV) and improved modelling of the core-level energy loss features. It provides depth distribution of deeply buried layers with very high sensitivity. We show that a conventional approach relying on intensities of the core-level peaks is unreliable due to intense plasmon losses. We reliably determine the depth distribution of 1 ML La in a high-?/metal gate stack capped with 50?nm a-Si. The method extends the sensitivity of photoelectron spectroscopy to depths beyond 50?nm.

  9. X-ray laser spectroscopy on lithium-like ions

    NASA Astrophysics Data System (ADS)

    Neumayer, Paul; Alvarez, J.; Becker-de Mos, Bruno; Borneis, Stefan; Brueck, K.; Gaul, Erhard W.; Haefner, C.; Janulewicz, Karol A.; Kuehl, Thomas; Marx, Dieter; Reinhard, Irene; Tomaselli, Marco; Nickles, Peter V.; Sandner, Wolfgang; Seelig, Wolfgang

    2001-12-01

    The Gesellschaft fuer Schwerionenforschung (GSI, Society for Heavy Ion Research) is currently the leading facility in the production of radioactive isotopes. Nuclear properties like charge radii, spin, and magnetic moments of exotic nuclei provide important data for testing of nuclear models. These properties are usually accessed by laser spectroscopy, which requires photon energies of around 100 eV in the case of lithium-like ions. We propose to use a transient gain X-ray laser (XRL) at the experimental storage ring (ESR) to perform this kind of spectroscopy. In this article we describe the planned experiments and give an overview of the current construction at GSI.

  10. The Astro-H Mission and High Resolution X-ray Spectroscopy

    Microsoft Academic Search

    Richard L. Kelley; K. Mitsuda; H. Awaki; R. Fujimoto; J. W. den Herder; M. Ishida; C. A. Kilbourne; H. Kunieda; Y. Maeda; D. McCammon; T. Ohashi; T. Okajima; F. Porter; P. Serlemitsos; Y. Soong; A. E. Szymkowiak; T. Takahashi; Y. Takei; M. Tashiro; Y. Tawara; N. Y. Yamasaki

    2010-01-01

    The Japan Aerospace Exploration Agency's Institute of Space and Aeronautical Science (JAXA\\/ISAS) is developing a major new high-energy astrophysics observatory. Astro-H will provide broadband, high-resolution spectroscopy and imaging over the 0.3-600 keV band using four co-aligned instruments operated simultaneously. The mission will have major US participation supported by NASA as well as contributions from Europe and Canada. For high-resolution x-ray

  11. X-ray absorption spectroscopy of photoionised plasmas at Z

    NASA Astrophysics Data System (ADS)

    Mancini, R. C.

    2011-06-01

    Photoionised plasmas are found in astrophysical environments such as x-ray binaries, active galactic nuclei, and in the accretion disks of compact objects. The Z facility at Sandia National Laboratories is a powerful source of x-rays that enables us to produce and study in the laboratory photoionised plasmas relevant for astrophysics under well characterized conditions. We discuss an experimental and theory/modeling effort in which the intense x-ray flux emitted at the collapse of a z-pinch experiment conducted at Z is employed to produce a neon photoionized plasma. The broad-band x-ray radiation flux from the z-pinch is used to both create the neon photoionised plasma and provide a source of backlighting photons to study the atomic kinetics through K-shell line absorption spectroscopy. The plasma is contained in a cm-scale gas cell located at about 5 cm from the z-pinch, and the filling pressure is carefully monitored all the way to shot time since it determines the particle number density of the plasma. Time-integrated and gated transmission spectra are recorded with a TREX spectrometer equipped with two elliptically-bent crystals and a set of slits to record up to six spatially-resolved spectra per crystal in the same shot. The spectral resolution is approximately 1000. The transmission data shows line absorption transitions in several ionization stages of neon including Be-, Li-, He- and H-like Ne ions. Detailed modeling calculations of the absorption spectra are used to interpret and model the high-resolution transmission spectra recorded in the Z experiments with the goal of extracting the ion population distribution of the plasma. Furthermore, the analysis of the gated data provides a window into the dynamics of the photoionized plasma. The data analysis is performed with the aid of a novel application of genetic algorithms to plasma spectroscopy.

  12. X-ray Absorption Spectroscopy: a powerful tool for the investigation

    E-print Network

    Morante, Silvia

    X-ray Absorption Spectroscopy: a powerful tool for the investigation of the role of metals is to illustrate the potentialities of X-ray Absorption Spectroscopy (XAS) to investigate structural properties Protein and Zinc ions 2 Introduction to the X-ray Absorption Spec- troscopy XAS uses Synchrotron Radiation

  13. Astrophysical X-Ray Spectroscopy: Then, Then Again, and Now

    NASA Astrophysics Data System (ADS)

    Kahn, S. M.

    2002-12-01

    For the last three years, the grating experiments on Chandra and XMM-Newton have been providing magnificent spectra of nearly all classes of cosmic X-ray sources. In most cases, these are the very first high resolution X-ray spectra we have had available. As an introduction to this meeting on High Resolution X-ray Spectroscopy with XMM-Newton and Chandra, I thought it might be fun to look back to where we came from, to get to where we are today in this field. I have chosen three snapshots in time: Then: Summer 1980 - I was driving across the U.S. (Berkeley to Boston). We had results from Uhuru, Ariel V, OSO 8, HEAO 1, and were just starting to get results from Einstein. Then Again: Summer 1995 - I was driving across the U.S. (Berkeley to NY). EXOSAT, BBXRT and ROSAT had flown in the interim. We were starting to get results from ASCA. Now: Summer 2002 - Chandra has been up for three years, XMM-Newton for 2 1/2. Astro-E tragically lost, but Astro-E2 in development.

  14. Research relative to high energy astrophysics. [large area modular array of reflectors, X-ray spectroscopy, and thermal control

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.

    1984-01-01

    Various parameters which affect the design of the proposed large area modular array of reflectors (LAMAR) are considered, including thermal control, high resolution X-ray spectroscopy, pointing control, and mirror performance. The LAMAR instrument is to be a shuttle-launched X-ray observatory to carry out cosmic X-ray investigations. The capabilities of LAMAR are enumerated. Angular resolution performance of the mirror module prototype was measured to be 30 sec of ARC for 50% of the power. The LAMAR thermal pre-collimator design concepts and test configurations are discussed in detail.

  15. The Future of X-ray Spectroscopy of Galactic Black Hole Binaries

    E-print Network

    Michael A. Nowak

    2003-12-18

    There are four major X-ray satellites currently in operation, with two more shortly to follow, and several very ambitious observatories in various stages of planning. This very rich period of X-ray observation is leading to great advances in our understanding of the accretion flow onto the black hole, although we are quickly learning (or perhaps better put, remembering) exactly how complicated this flow can be. This review was meant to assess future prospects for X-ray spectroscopy of black hole binaries; however, I first look backward to the observations and theories that helped us arrive at our current `paradigm'. I then discuss current and near-future spectroscopic studies, which increasingly (and very fruitfully) treat X-ray spectroscopy as part of a larger, intimately connected picture along with radio, optical, and gamma-ray spectroscopy. Equally importantly, and in large part thanks to the success of RXTE, there is now a strong realization that spectral-temporal correlations, even across wavelength bands, are crucial to our understanding of the physics of these systems. Going forward, we are well-poised to continue to advance our knowledge via X-ray spectroscopy, both with existing satellites that have a long lifetime ahead of them, and with the next generation of instruments. If there is any `hole' in this bright future, it is the potential loss of RXTE, with no designated follow-up mission. Studies of multi-wavelength spectral-temporal correlations will become more difficult due to the loss of two important attributes of RXTE: its fast timing capabilities and its extremely flexible scheduling which has made many of these studies possible.

  16. X-Ray Absorption Spectroscopy of Uranium Dioxide

    SciTech Connect

    Tobin, J G

    2010-12-10

    After the CMMD Seminar by Sung Woo Yu on the subject of the x-ray spectroscopy of UO2, there arose some questions concerning the XAS of UO2. These questions can be distilled down to these three issues: (1) The validity of the data; (2) The monchromator energy calibration; and (3) The validity of XAS component of the figure shown. The following will be shown: (1) The data is valid; (2) It is possible to calibrate the monchromator; and (3) The XAS component of the above picture is correct. The remainder of this document is in three sections, corresponding to these three issues.

  17. Fluorescence X-ray micro-spectroscopy activities at ESRF

    NASA Astrophysics Data System (ADS)

    Salomé, M.; Bleuet, P.; Bohic, S.; Cauzid, J.; Chalmin, E.; Cloetens, P.; Cotte, M.; De Andrade, V.; Martinez-Criado, G.; Petitgirard, S.; Rak, M.; Sans Tresserras, J. A.; Szlachetko, J.; Tucoulou, R.; Susini, J.

    2009-09-01

    The X-ray Microscopy and Micro-analysis beamlines at ESRF operate complementary state-of-the-art instruments at ID21, ID22, ID18F and more recently ID22NI. Within a multi-modal strategy, these beamlines develop micro-imaging techniques with various contrast mechanisms (?XRF, ?XANES, ?XRD and phase contrast) and host experiments with scientific topics ranging from Geochemistry to Archeology, Environmental sciences, Biology and Material sciences. Future challenges include pushing spatial resolution down to the nano-scale and the development of innovative 3D micro-analysis techniques.

  18. X-ray absorption spectroscopy: EXAFS (Extended X-ray Absorption Fine Structure) and XANES (X-ray Absorption Near Edge Structure)

    SciTech Connect

    Alp, E.E.; Mini, S.M.; Ramanathan, M.

    1990-04-01

    The x-ray absorption spectroscopy (XAS) had been an essential tool to gather spectroscopic information about atomic energy level structure in the early decades of this century. It has also played an important role in the discovery and systematization of rare-earth elements. The discovery of synchrotron radiation in 1952, and later the availability of broadly tunable synchrotron based x-ray sources have revitalized this technique since the 1970's. The correct interpretation of the oscillatory structure in the x-ray absorption cross-section above the absorption edge by Sayers et. al. has transformed XAS from a spectroscopic tool to a structural technique. EXAFS (Extended X-ray Absorption Fine Structure) yields information about the interatomic distances, near neighbor coordination numbers, and lattice dynamics. An excellent description of the principles and data analysis techniques of EXAFS is given by Teo. XANES (X-ray Absorption Near Edge Structure), on the other hand, gives information about the valence state, energy bandwidth and bond angles. Today, there are about 50 experimental stations in various synchrotrons around the world dedicated to collecting x-ray absorption data from the bulk and surfaces of solids and liquids. In this chapter, we will give the basic principles of XAS, explain the information content of essentially two different aspects of the absorption process leading to EXAFS and XANES, and discuss the source and samples limitations.

  19. Near Edge X-Ray Absorption Fine Structure Spectroscopy with X-Ray Free-Electron Lasers

    SciTech Connect

    Bernstein, D.P.; Acremann, Y.; Scherz, A.; Burkhardt, M.; Stohr, J.; /SLAC; Beye, M.; Schlotter, W.F.; Beeck, T.; Sorgenfrei, F.; Pietzsch, A.; Wurth, W.; Fohlisch, A.; /Hamburg U.

    2009-12-11

    We demonstrate the feasibility of Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy on solids by means of femtosecond soft x-ray pulses from a free-electron laser (FEL). Our experiments, carried out at the Free-Electron Laser at Hamburg (FLASH), used a special sample geometry, spectrographic energy dispersion, single shot position-sensitive detection and a data normalization procedure that eliminates the severe fluctuations of the incident intensity in space and photon energy. As an example we recorded the {sup 3}D{sub 1} N{sub 4,5}-edge absorption resonance of La{sup 3+}-ions in LaMnO{sub 3}. Our study opens the door for x-ray absorption measurements on future x-ray FEL facilities.

  20. Femtosecond time-resolved X-ray absorption spectroscopy of liquid using a hard X-ray free electron laser in a dual-beam dispersive detection method.

    PubMed

    Obara, Yuki; Katayama, Tetsuo; Ogi, Yoshihiro; Suzuki, Takayuki; Kurahashi, Naoya; Karashima, Shutaro; Chiba, Yuhei; Isokawa, Yusuke; Togashi, Tadashi; Inubushi, Yuichi; Yabashi, Makina; Suzuki, Toshinori; Misawa, Kazuhiko

    2014-01-13

    We present femtosecond time-resolved X-ray absorption spectroscopy of aqueous solution using a hard x-ray free electron laser (SACLA) and a synchronized Ti:sapphire laser. The instrumental response time is 200 fs, and the repetition rate of measurement is 10 Hz. A cylindrical liquid beam 100 ?m in diameter of aqueous ammonium iron(III) oxalate solution is photoexcited at 400 nm, and the transient X-ray absorption spectra are measured in the K-edge region of iron, 7.10 - 7.26 keV, using a dual X-ray beam dispersive detection method. Each of the dual beams has the pulse energy of 1.4 ?J, and pump-induced absorbance change on the order of 10(-3) is successfully detected. The photoexcited iron complex exhibits a red shifted iron K-edge with the appearance time constant of 260 fs. The X-ray absorption difference spectra, with and without the pump pulses, are independent of time delay after 1.5 ps up to 100 ps, indicating that the photoexcited species is long-lived. PMID:24515070

  1. Correlated single-crystal electronic absorption spectroscopy and X-ray crystallography at NSLS beamline X26-C

    SciTech Connect

    Orville, A.M.; Buono, R.; Cowan, M.; Heroux, A.; Shea-McCarthy, G.; Schneider, D. K.; Skinner, J. M.; Skinner, M. J.; Stoner-Ma, D.; Sweet, R. M.

    2011-05-01

    The research philosophy and new capabilities installed at NSLS beamline X26-C to support electronic absorption and Raman spectroscopies coupled with X-ray diffraction are reviewed. This beamline is dedicated full time to multidisciplinary studies with goals that include revealing the relationship between the electronic and atomic structures in macromolecules. The beamline instrumentation has been fully integrated such that optical absorption spectra and X-ray diffraction images are interlaced. Therefore, optical changes induced by X-ray exposure can be correlated with X-ray diffraction data collection. The installation of Raman spectroscopy into the beamline is also briefly reviewed. Data are now routinely generated almost simultaneously from three complementary types of experiments from the same sample. The beamline is available now to the NSLS general user population.

  2. Correlated Single-Crystal Electronic Absorption Spectroscopy and X-ray Crystallography at NSLS Beamline X26-C

    SciTech Connect

    A Orville; R Buono; M Cowan; A Heroux; G Shea-McCarthy; D Schneider; J Skinner; M Skinner; D Stoner-Ma; R Sweet

    2011-12-31

    The research philosophy and new capabilities installed at NSLS beamline X26-C to support electronic absorption and Raman spectroscopies coupled with X-ray diffraction are reviewed. This beamline is dedicated full time to multidisciplinary studies with goals that include revealing the relationship between the electronic and atomic structures in macromolecules. The beamline instrumentation has been fully integrated such that optical absorption spectra and X-ray diffraction images are interlaced. Therefore, optical changes induced by X-ray exposure can be correlated with X-ray diffraction data collection. The installation of Raman spectroscopy into the beamline is also briefly reviewed. Data are now routinely generated almost simultaneously from three complementary types of experiments from the same sample. The beamline is available now to the NSLS general user population.

  3. Correlated single-crystal electronic absorption spectroscopy and X-ray crystallography at NSLS beamline X26-C

    PubMed Central

    Orville, Allen M.; Buono, Richard; Cowan, Matt; Héroux, Annie; Shea-McCarthy, Grace; Schneider, Dieter K.; Skinner, John M.; Skinner, Michael J.; Stoner-Ma, Deborah; Sweet, Robert M.

    2011-01-01

    The research philosophy and new capabilities installed at NSLS beamline X26-C to support electronic absorption and Raman spectroscopies coupled with X-ray diffraction are reviewed. This beamline is dedicated full time to multidisciplinary studies with goals that include revealing the relationship between the electronic and atomic structures in macromolecules. The beamline instrumentation has been fully integrated such that optical absorption spectra and X-ray diffraction images are interlaced. Therefore, optical changes induced by X-ray exposure can be correlated with X-ray diffraction data collection. The installation of Raman spectroscopy into the beamline is also briefly reviewed. Data are now routinely generated almost simultaneously from three complementary types of experiments from the same sample. The beamline is available now to the NSLS general user population. PMID:21525643

  4. Multi-criteria Search and Optimization: an Application to X-ray Plasma Spectroscopy

    E-print Network

    Louis, Sushil J.

    Multi-criteria Search and Optimization: an Application to X-ray Plasma Spectroscopy Igor E 89557 Reno, NV 89557 Reno, NV 89557 golovkin@physics.unr.edu rcman@physics.unr.edu sushil@cs.unr.edu X-ray X-ray spectroscopic analysis has been widely used as a standard technique to determine temperature

  5. Electronic Structure of In2O3 from Resonant X-ray Emission Spectroscopy

    SciTech Connect

    Piper, L.; DeMasi, A; Cho, S; Smith, K; Fuchs, F; Bechstedt, F; Korber, C; Klein, A; Payne, D; Egdell, R

    2009-01-01

    The valence and conduction band structures of In2O3 have been measured using a combination of valence band x-ray photoemission spectroscopy, O K-edge resonant x-ray emission spectroscopy, and O K-edge x-ray absorption spectroscopy. Excellent agreement is noted between the experimental spectra and O 2p partial density of states calculated within hybrid density functional theory. Our data are consistent with a direct band gap for In2O3.

  6. CUBIC - A non-dispersive Diffuse X-ray Background spectrometer. [Cosmic Unresolved X-ray Background Instrument

    NASA Technical Reports Server (NTRS)

    Burrows, David N.; Skinner, Mark A.; Antunes, Alexander J. D.; Catalano, Mark A.; Cocklin, Eric J.; Engel, Leland G.; Entingh, Timothy J.; Garmire, Gordon P.; Green, Roland; Kelly, Douglas A.

    1992-01-01

    The Cosmic Unresolved X-ray Background Instrument using CCDs (CUBIC) is designed to obtain spectral observations of the Diffuse X-ray Background (DXRB) with moderate spectral resolution over the energy range 0.2-10 keV, using mechanically-collimated CCDs. At this time, it is the only planned satellite payload devoted to the study of the spectrum of the DXRB. Over the anticipated 3 year lifetime of the satellite, CUBIC will be able to study up to 50 percent of the sky with 5 x 5 deg spatial resolution for the subkilovolt Galactic diffuse background, and with 10 x 10 deg spatial resolution for the extragalactic diffuse background above 2 keV. CUBIC will obtain high quality nondispersive spectra of soft X-ray emission from the interstellar medium, supernova remnants, and some bright sources, and will make a sensitive seach for line emission or other features in the extragalactic cosmic X-ray background from 2-10 keV.

  7. X-ray photon spectroscopy with the YOHKOH Soft X-ray telescope

    Microsoft Academic Search

    B. Labonte; K. Reardon

    1997-01-01

    Individual X-ray photons in the keV energy range produce hundreds of photoelectrons in a single pixel of a CCD array detector. The number of photoelectrons produced is a linear function of the photon energy, allowing the measurement of spectral information with an imaging detector system. The Yohkoh Soft X-ray Telescope uses a CCD in an integrating mode and makes temperature

  8. X-ray spectroscopy and imaging of a plasma collision

    NASA Astrophysics Data System (ADS)

    Chenais-Popovics, Claude J.; Rancu, Ovidiu N.; Renaudin, P.; Gauthier, Jean-Claude J.; Gilleron, F.; Lindenmeyer, O.; Kawagoshi, H.; Dirksmoeller, M.; Uschmann, Ingo; Missalla, Thomas; Sondhauss, P. C.; Foerster, Eckhart; Renner, Oldrich; Krousky, E.; Pepin, Henri; Larroche, O.; Peyrusse, Olivier; Shepard, Terry D.

    1995-09-01

    The collision of laser-produced plasmas has been diagnosed by x-ray spectroscopy and imaging. The two colliding plasmas are produced on Al thin foils at a distance of 200 to 900 micrometers irradiated at (lambda) equals 0.53 micrometers with laser intensities of 3 X 1013 to 6 X 1013 W/cm2. Interpretation of the plasmas was visualized by replacing one of the foils material by magnesium. The main diagnostics were x-ray crystal optics based on flat, cylindrical, and toroidal crystals viewing the inter-target space. A multifluid eulerian monodimensional hydrodynamic code coupled with a radiative-atomic package provided simulations of the experiments. Hydrodynamic 2D simulations calculating the lateral expansion of the plasma enabled a reliable treatment of reabsorption along the line of sight of the spectrographs. The size and the time duration of the collision, the plasma parameters in the collision region (Te, Ti, and ne) and interpenetration were measured. The hydrocode simulations give a good understanding of the behavior of the collision in function of intertarget distance and laser intensity.

  9. Simulated X-Ray Absorption Spectroscopy on the Water Dimer

    SciTech Connect

    Wung, A

    2004-02-05

    The ability of an individual H{sub 2}O molecule to form multiple hydrogen bonds with neighboring molecules makes it an ideal substance for the study of hydrogen bonding. X-ray absorption spectroscopy (XAS) can be used to study what intermolecular structures the hydrogen-bonded water molecules form. XAS excites core electrons from the oxygen 1 s atomic orbital to an unoccupied orbital. The resulting absorption spectrum shows the energy levels of the unoccupied orbitals, which in turn is dependent on the intermolecular structure of the H{sub 2}O system. Previous studies using molecular dynamics computer simulations have concluded that the intermolecular structure of liquid water is a distorted tetrahedron. Yet x-ray absorption spectra show discrepancies between liquid water and ice Ih, which is already known to have a rigid tetrahedral structure. The research group, which is based in the University of Sweden in Stockholm and the Stanford Synchrotron Radiation Laboratory at the Stanford Linear Accelerator Center, has studied the possible presence of broken hydrogen bonds in the liquid water intermolecular structure to explain these deviations. Computer simulations are used to construct theoretical absorption spectra for models of liquid water including broken hydrogen bonds. Creating such models requires controlling variables. The simplest method of isolating individual variables, such as hydrogen bond length and angles, is to study the water dimer. Here, the water dimer is used to study how the absorption spectra change with the way the water molecules are positioned and oriented relative to each other.

  10. Study of surface films of overbased sulfonates and sulfurized olefins by X-Ray Absorption Near Edge Structure (XANES) spectroscopy

    Microsoft Academic Search

    Michael T. Costello; Masoud Kasrai

    2006-01-01

    The X-Ray Absorption Near Edge Structure (XANES) spectroscopy technique has been successfully applied to complex matrices such as tribological films, coal, DLC films and, where other instrumental analytical techniques are less sensitive for molecular analysis. Four-ball tests were performed for lubricating oils containing the synergistic combination of overbased sulfonate (calcium and magnesium) and sulfurized olefin. The surface films were analyzed

  11. X-Ray Imaging-Spectroscopy of Abell 1835

    NASA Technical Reports Server (NTRS)

    Peterson, J. R.; Paerels, F. B. S.; Kaastra, J. S.; Arnaud, M.; Reiprich T. H.; Fabian, A. C.; Mushotzky, R. F.; Jernigan, J. G.; Sakelliou, I.

    2000-01-01

    We present detailed spatially-resolved spectroscopy results of the observation of Abell 1835 using the European Photon Imaging Cameras (EPIC) and the Reflection Grating Spectrometers (RGS) on the XMM-Newton observatory. Abell 1835 is a luminous (10(exp 46)ergs/s), medium redshift (z = 0.2523), X-ray emitting cluster of galaxies. The observations support the interpretation that large amounts of cool gas are present in a multi-phase medium surrounded by a hot (kT(sub e) = 8.2 keV) outer envelope. We detect O VIII Ly(alpha) and two Fe XXIV complexes in the RGS spectrum. The emission measure of the cool gas below kT(sub e) = 2.7 keV is much lower than expected from standard cooling-flow models, suggesting either a more complicated cooling process than simple isobaric radiative cooling or differential cold absorption of the cooler gas.

  12. heterojunction interface investigated by X-ray photoemission spectroscopy

    NASA Astrophysics Data System (ADS)

    Lin, Lingyan; Yu, Jinling; Cheng, Shuying; Lu, Peimin; Lai, Yunfeng; Lin, Sile; Zhao, Pengyi

    2014-09-01

    The band alignment at the In2S3/Cu2ZnSnS4 heterojunction interface is investigated by X-ray photoemission spectroscopy. In2S3 is thermally evaporated onto the contamination-free polycrystalline Cu2ZnSnS4 surface prepared by magnetron sputtering. The valence band offset is measured to be 0.46 ± 0.1 eV, which matches well with the valance band offset value 0.49 eV calculated using "transitivity" method. The conduction band offset is determined to be 0.82 ± 0.1 eV, indicating a `type I' band alignment at the heterojunction interface.

  13. Femtosecond high-resolution hard X-ray spectroscopy using reflection zone plates.

    PubMed

    Löchel, Heike; Braig, Christoph; Brzhezinskaya, Maria; Siewert, Frank; Baumgärtel, Peter; Firsov, Alexander; Erko, Alexei

    2015-04-01

    An off-axis total external reflection zone plate is applied to wavelength-dispersive X-ray spectrometry in the range from 7.8 keV to 9.0 keV. The resolving power E/?E of up to 1.1 × 102, demonstrated in a synchrotron proof-of-concept experiment, competes well with existing energy-dispersive instruments in this spectral range. In conjunction with the detection efficiency of (2.2 ± 0.6)%, providing a fairly constant count rate across the 1.2 keV band, the temporal pulse elongation to no more than 1.5 × 10-15 s opens the door to wide-range, ultra-fast hard X-ray spectroscopy at free-electron lasers (FELs). PMID:25968716

  14. Powerful microfocus x-ray and hard x-ray 1 MA x-pinch plasma source for imaging, spectroscopy, and polarimetry

    Microsoft Academic Search

    Victor L. Kantsyrev; Bruno S. Bauer; Alla S. Shlyaptseva; Dmitri A. Fedin; Stephanie Hansen; Radu Presura; Stephan Fuelling; Steve Batie; Andrew Oxner; Harold Faretto; Nick D. Ouart; Sean Keely; Hank LeBeau; David Chamberlain

    2001-01-01

    The x-ray emission of Ti, Fe, Mo, W and Pt x-pinches are currently bieng studied at the Nevada Terawatt Facility z- pinch machine (0.9-1.0 MA, 100 ns). New x-ray diagnostics for time-resolved spectroscopy and imaging has been developed and used in x-pinch experiments. The total x- ray\\/EUV yield was more than 10 kJ. The minimum x-ray pulse duration was 1.1

  15. Synchrotron Radiation X-ray Diffraction and X-ray Photoelectron Spectroscopy Investigation on Si-based Structures for SubMicron Si-IC Applications

    Microsoft Academic Search

    Zhe Chuan Feng; Li-Chi Cheng; Chu-Wan Huang; Ying-Lang Wang; T. R. Yang

    2006-01-01

    Synchrotron radiation X-ray diffraction and X-ray photoelectron spectroscopy techniques have been employed for the investigation on Si-based layer structures for sub-micron Si-IC Applications. The high energy synchrotron radiation light sources have produced plenty of X-ray lines with high index diffraction and strong X-ray photoelectron emissions. The useful information will increase our understanding of these materials which are applied extensively to

  16. XEUS The X-ray Evolving Universe Spectroscopy Mission

    E-print Network

    Parmar, A N; Bavdaz, M; Hasinger, G; Arnaud, M; Barcons, X; Barret, D; Blanchard, A; Böhringer, H; Cappi, M; Comastri, A; Courvoisier, Thierry J L; Fabian, A C; Griffiths, R; Malaguti, P; Mason, K O; Ohashi, T; Paerels, F B S; Piro, L; Schmitt, J; Van der Klis, M; Ward, M

    1999-01-01

    XEUS is under study by ESA as part of the Horizon 2000+ program to utilize the International Space Station (ISS) for astronomical applications. XEUS will be a long-term X-ray observatory with an initial mirror area of 6m2 at 1 keV that will be grown to 30m2 following a visit to the ISS. The 1 keV spatial resolution is expected to be 2-5'' HEW. XEUS will consist of separate detector and mirror spacecraft aligned by active control to provide a focal length of 50m. A new detector spacecraft, complete with the next generation of instruments, will also be added after visiting the ISS. The limiting sensitivity will then be ~4 10-18 erg/cm2/s - around 250 times better than XMM, allowing XEUS to study the properties of the hot baryons and dark matter at high redshift.

  17. XEUS - The X-ray Evolving Universe Spectroscopy Mission

    E-print Network

    A. N. Parmar; T. Peacock; M. Bavdaz; G. Hasinger; M. Arnaud; X. Barcons; D. Barret; A. Blanchard; H. Bohringer; M. Cappi; A. Comastri; T. Courvoisier; A. C. Fabian; R. Griffiths; P. Malaguti; K. O. Mason; T. Ohashi; F. Paerels; L. Piro; J. Schmitt; M. van der Klis; M. Ward

    1999-11-29

    XEUS is under study by ESA as part of the Horizon 2000+ program to utilize the International Space Station (ISS) for astronomical applications. XEUS will be a long-term X-ray observatory with an initial mirror area of 6m2 at 1 keV that will be grown to 30m2 following a visit to the ISS. The 1 keV spatial resolution is expected to be 2-5'' HEW. XEUS will consist of separate detector and mirror spacecraft aligned by active control to provide a focal length of 50m. A new detector spacecraft, complete with the next generation of instruments, will also be added after visiting the ISS. The limiting sensitivity will then be ~4 10-18 erg/cm2/s - around 250 times better than XMM, allowing XEUS to study the properties of the hot baryons and dark matter at high redshift.

  18. Possible planetary XRF instrument with X-ray generator

    NASA Astrophysics Data System (ADS)

    Yin, Lo I.; Trombka, Jacob I.

    1986-01-01

    We explore in this paper the possibility of a planetary in situ XRF system using a newly developed battery-operated miniature X-ray generator as the excitation source. Furthermore, recent advances in refrigeration technology and HgI2 detectors make it possible to consider realistically the inclusion of a high-resolution energy-dispersive spectrometer as part of the system. It will be shown that by the simple coupling of the miniature X-ray generator and a standard Si(Li) detector qualitative characterization of geochemical samples can be easily carried out without elaborate calibrations and spectrum stripping. Similar battery-operated miniature X-ray generators with a variety of anodes are now commercially available.

  19. X-ray photoelectron spectroscopy and ion scattering spectroscopy characterization of coated and uncoated PETN

    Microsoft Academic Search

    Pu Sen Wang; T. N. Wittberg

    1984-01-01

    Surface structures of PETN and plastic bonded PETN were studied by high resolution X-Ray Photoelectron Spectroscopy (XPS) and Ion Scattering Spectroscopy (ISS). The coating material is a copolymer of vinyl chloride and chlorotrifluoroethylene. Specimen with 4 wt. Z coating material on PETN were used in these studies. High resolution elemented XPS spectra of F ls, N ls, C ls, and

  20. High Resolution X-Ray Imaging and Spectroscopy of AGN and SS 433 with the Chandra X-Ray Observatory

    NASA Astrophysics Data System (ADS)

    Marshall, H. L.

    2000-04-01

    We present some early results on AGN and jets with the Chandra X-ray Observatory, highlighting high resolution spectroscopy using the High Energy Transmission Grating Spectrometer (HETGS). The quasar PKS 0637--752 was found to have a very bright X-ray jet whose shape is remarkably similar to that of the radio jet on a size scale of 100 kpc but the X-ray emission is still unexplainably bright. Two BL Lac objects, PKS 2155--304 and Mk 421, were observed with the spectrometer and found to have no strong absorption or emission features. Other radio loud AGN observed with the HETGS show simple power law spectra without obvious features. These AGN results stand in marked contrast to the line-rich spectrum of SS 433, a Galactic X-ray binary which has relativistic jets. Broadened X-ray emission lines of H- and He-like S and Si are used to show that the characteristic temperature of the jet is near 2.5 keV at its base.

  1. High-efficiency blazed transmission gratings for high-resolution soft x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Heilmann, Ralf K.; Bruccoleri, Alexander R.; Schattenburg, Mark L.

    2015-01-01

    High-resolution spectroscopy of astrophysical sources is the key to gaining a quantitative understanding of the history, dynamics, and current conditions of the cosmos. A large-area (> 1,000 cm2), high resolving power (R = ?/?? > 3,000) soft x-ray spectrometer that covers the lines of C, N, O, Ne and Fe ions is the ideal tool to address a number of high-priority sciences questions from the 2010 Decadal Survey, such as the connection between super-massive black holes and large-scale structure via cosmic feedback, the evolution of large-scale structure, the behavior of matter at high densities, and the conditions close to black holes. Numerous mission concepts that meet these requirements have been studied and proposed over the last few years, including grating instruments for the International X-ray Observatory. Nevertheless, no grating missions are currently approved. To improve the chances for future soft x-ray grating spectroscopy missions, grating technology has to progress and be advanced to higher TRLs. We have developed Critical-Angle Transmission (CAT) gratings that combine the advantages of blazed reflection gratings (high efficiency, use of higher diffraction orders) with those of conventional transmission gratings (low mass, relaxed alignment tolerances and temperature requirements, transparent at higher energies). A CAT grating-based spectrometer can provide performance 1-2 orders of magnitude better than current grating instruments on Chandra and Newton-XMM with minimal resource requirements. We have fabricated large-area free-standing CAT gratings with minimal integrated support structures from silicon-on-insulator wafers using advanced lithography and a combination of deep reactive-ion and wet etching, and will present our latest x-ray test results showing record high diffraction efficiencies in blazed orders.

  2. Effect of higher z dopants on implosion dynamics: X-ray spectroscopy

    E-print Network

    Effect of higher z dopants on implosion dynamics: X-ray spectroscopy George A. Kyrala a,*, Douglas the dynamics of the implosion as it increases the electron density, which increases the radiation losses from 2007 Elsevier B.V. All rights reserved. Keywords: Inertial fusion; Implosions; X-ray spectroscopy 1

  3. The Soft X-ray Research instrument at the Linac Coherent Light Source.

    PubMed

    Dakovski, Georgi L; Heimann, Philip; Holmes, Michael; Krupin, Oleg; Minitti, Michael P; Mitra, Ankush; Moeller, Stefan; Rowen, Michael; Schlotter, William F; Turner, Joshua J

    2015-05-01

    The Soft X-ray Research instrument provides intense ultrashort X-ray pulses in the energy range 280-2000?eV. A diverse set of experimental stations may be installed to investigate a broad range of scientific topics such as ultrafast chemistry, highly correlated materials, magnetism, surface science, and matter under extreme conditions. A brief description of the main instrument components will be given, followed by some selected scientific highlights. PMID:25931059

  4. The Soft X-ray research instrument at the Linac Coherent Light Source

    DOE PAGESBeta

    Dakovski, Georgi L.; Heimann, Philip; Holmes, Michael; Krupin, Oleg; Minitti, Michael P.; Mitra, Ankush; Moeller, Stefan; Rowen, Michael; Schlotter, William F.; Turner, Joshua J.

    2015-05-01

    The Soft X-ray Research instrument provides intense ultrashort X-ray pulses in the energy range 280–2000 eV. A diverse set of experimental stations may be installed to investigate a broad range of scientific topics such as ultrafast chemistry, highly correlated materials, magnetism, surface science, and matter under extreme conditions. A brief description of the main instrument components will be given, followed by some selected scientific highlights.

  5. A high-temperature Bonse-Hart ultrasmall-angle x-ray scattering instrument

    Microsoft Academic Search

    Benjamin Chu; Yingjie Li; Paul J. Harney; Fengji Yeh

    1993-01-01

    A Bonse–Hart ultrasmall-angle x-ray scattering (USAXS) instrument has been designed, constructed, and tested employing a synchrotron x-ray source. The instrument permits experiments ranging from below 0 °C up to about 400 °C, as well as temperature scanning, jumping, quenching, and annealing experiments. The mechanical elements used Super Invar as the basic building material in order to minimize the thermal expansion

  6. The Soft X-ray Research instrument at the Linac Coherent Light Source

    PubMed Central

    Dakovski, Georgi L.; Heimann, Philip; Holmes, Michael; Krupin, Oleg; Minitti, Michael P.; Mitra, Ankush; Moeller, Stefan; Rowen, Michael; Schlotter, William F.; Turner, Joshua J.

    2015-01-01

    The Soft X-ray Research instrument provides intense ultrashort X-ray pulses in the energy range 280–2000?eV. A diverse set of experimental stations may be installed to investigate a broad range of scientific topics such as ultrafast chemistry, highly correlated materials, magnetism, surface science, and matter under extreme conditions. A brief description of the main instrument components will be given, followed by some selected scientific highlights. PMID:25931059

  7. Characterization of LCLS X-Ray Pulses Using Atomic Spectroscopy

    Microsoft Academic Search

    A. M. March; L. Young; S. H. Southworth; E. P. Kanter; B. Krässig; R. Santra; Y. Li; S. T. Pratt; N. Berrah; M. Höner; L. Fang; J. P. Cryan; J. M. Glownia; D. A. Reis; S. Ghimire; P. Bucksbaum; L. Dimauro; G. Doumy; C. Roedig; J. D. Bozek; C. Bostedt; M. Messerschmidt

    2010-01-01

    The first experiments at the LCLS succeeded in not only revealing the nature of interactions between intense x-rays and atomic or molecular systems, but also properties of the LCLS x-ray pulses. Our spectroscopic measurements of the interaction with neon atoms have revealed information on x-ray photon energy, the pulse duration, and the focal spot size. When analyzed in conjunction with

  8. Detection limits for actinides in a monochromatic, wavelength-dispersive x-ray fluorescence instrument

    SciTech Connect

    Collins, Michael L [Los Alamos National Laboratory; Havrilla, George J [Los Alamos National Laboratory

    2009-01-01

    Recent developments in x-ray optics have made it possible to examine the L x-rays of actinides using doubly-curved crystals in a bench-top device. A doubly-curved crystal (DCC) acts as a focusing monochromatic filter for polychromatic x-rays. A Monochromatic, Wavelength-Dispersive X-Ray Fluorescence (MWDXRF) instrument that uses DCCs to measure Cm and Pu in reprocessing plant liquors was proposed in 2007 by the authors at Los Alamos National Laboratory. A prototype design of this MWDXRF instrument was developed in collaboration with X-ray Optical Systems Inc. (XOS), of East Greenbush, New York. In the MWDXRF instrument, x-rays from a Rhodium-anode x-ray tube are passed through a primary DCC to produce a monochromatic beam of 20.2-keV photons. This beam is focused on a specimen that may contain actinides. The 20.2-keV interrogating beam is just above the L3 edge of Californium; each actinide (with Z = 90 to 98) present in the specimen emits characteristic L x-rays as the result of L3-shell vacancies. In the LANL-XOS prototype MWDXRf, these x-rays enter a secondary DCC optic that preferentially passes 14.961-keV photons, corresponding to the L-alpha-1 x-ray peak of Curium. In the present stage of experimentation, Curium-bearing specimens have not been analyzed with the prototype MWDXRF instrument. Surrogate materials for Curium include Rubidium, which has a K-beta-l x-ray at 14.961 keV, and Yttrium, which has a K-alpha-1 x-ray at 14.958 keV. In this paper, the lower limit of detection for Curium in the LANL-XOS prototype MWDXRF instrument is estimated. The basis for this estimate is described, including a description of computational models and benchmarking techniques used. Detection limits for other actinides are considered, as well as future safeguards applications for MWDXRF instrumentation.

  9. Making use of x-ray optical effects in photoelectron-, Auger electron-, and x-ray emission spectroscopies: Total reflection, standing-wave excitation,

    E-print Network

    Fadley, Charles

    spectroscopies: Total reflection, standing-wave excitation, and resonant effects S.-H. Yang, A. X. Gray, A. M spectroscopies: Total reflection, standing-wave excitation, and resonant effects S.-H. Yang,1 A. X. Gray,2,3,4 AMaking use of x-ray optical effects in photoelectron-, Auger electron-, and x-ray emission

  10. Surface arsenic speciation of a drinking-water treatment residual using X-ray absorption spectroscopy

    Microsoft Academic Search

    Konstantinos C. Makris; Dibyendu Sarkar; Jason G. Parsons; Rupali Datta; Jorge L. Gardea-Torresdey

    2007-01-01

    Drinking-water treatment residuals (WTRs) present a low-cost geosorbent for As-contaminated waters and soils. Previous work has demonstrated the high affinity of WTRs for As, but data pertaining to the stability of sorbed As is missing. Sorption\\/desorption and X-ray absorption spectroscopy (XAS), both XANES (X-ray absorption near edge structure) and EXAFS (extended X-ray absorption fine structure) studies, were combined to determine

  11. Surface Arsenic Speciation of a Drinking-Water Treatment Residual Using X-Ray Absorption Spectroscopy

    Microsoft Academic Search

    K. C. Makris; D. Sarkar; J. G. Parsons; R. Datta; J. L. Gardea-Torresdey

    2009-01-01

    Drinking-water treatment residuals (WTRs) present a low-cost geosorbent for As-contaminated waters and soils. Previous work has demonstrated the high affinity of WTRs for As, but data pertaining to the stability of sorbed As is missing. Sorption\\/desorption and X-ray absorption spectroscopy (XAS), both XANES (X-ray absorption near edge structure) and EXAFS (extended X-ray absorption fine structure) studies, were combined to determine

  12. X-ray emission spectroscopy applied for bulk and individual analysis of airborne particulates

    NASA Astrophysics Data System (ADS)

    Valkovic, V.; Dargie, Marina; Jaksic, M.; Markowicz, A.; Tajani, Antonella; Valkovic, O.

    1996-06-01

    It has been shown that filters used for collection of airborne particles by high volume air samplers can yield information on the particles' elemental composition when analyzed by X-ray emission spectroscopy methods. In this work we present some results on trace element characterization (both bulk and individual particles) of air particulates by X-ray fluorescence (in normal and total reflection geometry) and proton induced X-ray emission (in standard and microbeam geometry).

  13. Near Edge X-ray Absorption Spectroscopy of Polymers

    NASA Astrophysics Data System (ADS)

    Dhez, Olivier; Ade, Harald; Urquhart, Stephen

    2001-03-01

    Synthetic and natural polymers exhibit a rich carbon, nitrogen and oxygen K-edge Near Edge X-ray Absorption Fine Structure (NEXAFS). The spectroscopic variations with chemical structure and composition are interesting in their own right. In addition, the large spectroscopic variability can be utilized for the compositional analysis of materials. This is particularly useful for high spatial resolution NEXAFS microanalysis at lateral spatial resolutions exceeding that achievable with more traditional compositional analysis tools such as Infrared and NMR spectroscopy. To increase our understanding of NEXAFS spectra and to start a database for microanalysis, we acquired carbon NEXAFS spectra of the following polymers: polycarbonate, poly(oxybenzoate-co-2,6oxynaphthoate), poly (p-phenylene terephtalamide), toluene diisocyanate polyurethane, toluene diisocyanate polyurea, 4,4'-methylene di-p-phenylene isocyanate polyurethane, 4,4'-methylene di-p-phenylene isocyanate polyurea, poly(ether ether ketone), poly(alpha-methylstyrene), poly-styrene, poly bromostyrene, poly(2-vinyl styrene), polyethylene, poly(ethylene oxide), polypropylene, poly(propylene oxide), polyisobutylene, ethylene propylene rubber, poly(methyl -metacrylate). These spectra were obtained in transmission with an energy resolution of 150 meV. The energy scale was carefully calibrated in-situ utilizing C02 gas as a reference. Spectral assignments are made based on model compounds and theoretical calculations.

  14. X-ray Imaging and Spectroscopy in Space

    NASA Astrophysics Data System (ADS)

    Schnopper, Herbert

    2002-04-01

    Extra-solar X-ray astronomy became a reality in 1962 after a successful rocket flight discovered an X-ray source in the constellation Scorpius. The X-ray "telescope" consisted of a roughly collimated Geiger counter. New sources were discovered by many groups in a rapid series of rocket flights that were characterized by finer angular and spectral measurements made with better mechanical collimators and proportional detectors. These discoveries led to the association of the newly discovered X-ray sources with objects already know in other wavelength bands. It was quickly understood that high precision measurements of angular position, spectral features and timing fluctuations were needed to make physical sense of the X-ray data and to put it into the context of the wealth of data obtained from other wavelength bands. These needs were met by a succession of major missions that began with UHURU (1970) and followed with the X-ray telescopes on EINSTEIN (1977), EXOSAT (1983), ROSAT (1990), GINGA (1987), ASCA (1993), CHANDRA (1999) and XMM.(1999). Each brought greater precision to measurements that allowed highly refined interpretations of the properties of x-ray sources. Several of the technical milestones that made these advances possible will be discussed.

  15. The Coherent X-ray Imaging instrument at the Linac Coherent Light Source.

    PubMed

    Liang, Mengning; Williams, Garth J; Messerschmidt, Marc; Seibert, M Marvin; Montanez, Paul A; Hayes, Matt; Milathianaki, Despina; Aquila, Andrew; Hunter, Mark S; Koglin, Jason E; Schafer, Donald W; Guillet, Serge; Busse, Armin; Bergan, Robert; Olson, William; Fox, Kay; Stewart, Nathaniel; Curtis, Robin; Miahnahri, Alireza Alan; Boutet, Sébastien

    2015-05-01

    The Coherent X-ray Imaging (CXI) instrument specializes in hard X-ray, in-vacuum, high power density experiments in all areas of science. Two main sample chambers, one containing a 100?nm focus and one a 1?µm focus, are available, each with multiple diagnostics, sample injection, pump-probe and detector capabilities. The flexibility of CXI has enabled it to host a diverse range of experiments, from biological to extreme matter. PMID:25931062

  16. The NOAA Goes12 Solar X-Ray Imager (SXI) 1. Instrument, Operations, and Data

    Microsoft Academic Search

    S. M. Hill; V. J. Pizzo; C. C. Balch; D. A. Biesecker; P. Bornmann; E. Hildner; L. D. Lewis; R. N. Grubb; M. P. Husler; K. Prendergast; J. Vickroy; S. Greer; T. Defoor; D. C. Wilkinson; R. Hooker; P. Mulligan; E. Chipman; H. Bysal; J. P. Douglas; R. Reynolds; J. M. Davis; K. S. Wallace; K. Russell; K. Freestone; D. Bagdigian; T. Page; S. Kerns; R. Hoffman; S. A. Cauffman; M. A. Davis; R. Studer; F. E. Berthiaume; T. T. Saha; G. D. Berthiume; H. Farthing; F. Zimmermann

    2005-01-01

    The Solar X-ray Imager (SXI) was launched 23 July 2001 on NOAA’s GOES-12 satellite and completed post-launch testing 20 December 2001. Beginning 22 January 2003 it has provided nearly uninterrupted, full-disk, soft X-ray solar images, with a continuous frame rate significantly exceeding that for previous similar instruments. The SXI provides images with a 1 min cadence and a single-image (adjustable)

  17. The Coherent X-ray Imaging instrument at the Linac Coherent Light Source

    PubMed Central

    Liang, Mengning; Williams, Garth J.; Messerschmidt, Marc; Seibert, M. Marvin; Montanez, Paul A.; Hayes, Matt; Milathianaki, Despina; Aquila, Andrew; Hunter, Mark S.; Koglin, Jason E.; Schafer, Donald W.; Guillet, Serge; Busse, Armin; Bergan, Robert; Olson, William; Fox, Kay; Stewart, Nathaniel; Curtis, Robin; Miahnahri, Alireza Alan; Boutet, Sébastien

    2015-01-01

    The Coherent X-ray Imaging (CXI) instrument specializes in hard X-ray, in-vacuum, high power density experiments in all areas of science. Two main sample chambers, one containing a 100?nm focus and one a 1?µm focus, are available, each with multiple diagnostics, sample injection, pump–probe and detector capabilities. The flexibility of CXI has enabled it to host a diverse range of experiments, from biological to extreme matter. PMID:25931062

  18. The Coherent X-ray Imaging instrument at the Linac Coherent Light Source

    DOE PAGESBeta

    Liang, Mengning; Williams, Garth J.; Messerschmidt, Marc; Seibert, M. Marvin; Montanez, Paul A.; Hayes, Matt; Milathianaki, Despina; Aquila, Andrew; Hunter, Mark S.; Koglin, Jason E.; et al

    2015-05-01

    The Coherent X-ray Imaging (CXI) instrument specializes in hard X-ray, in-vacuum, high power density experiments in all areas of science. Two main sample chambers, one containing a 100 nm focus and one a 1 µm focus, are available, each with multiple diagnostics, sample injection, pump–probe and detector capabilities. The flexibility of CXI has enabled it to host a diverse range of experiments, from biological to extreme matter.

  19. The soft x-ray instrument for materials studies at the linac coherent light source x-ray free-electron laser.

    PubMed

    Schlotter, W F; Turner, J J; Rowen, M; Heimann, P; Holmes, M; Krupin, O; Messerschmidt, M; Moeller, S; Krzywinski, J; Soufli, R; Fernández-Perea, M; Kelez, N; Lee, S; Coffee, R; Hays, G; Beye, M; Gerken, N; Sorgenfrei, F; Hau-Riege, S; Juha, L; Chalupsky, J; Hajkova, V; Mancuso, A P; Singer, A; Yefanov, O; Vartanyants, I A; Cadenazzi, G; Abbey, B; Nugent, K A; Sinn, H; Lüning, J; Schaffert, S; Eisebitt, S; Lee, W-S; Scherz, A; Nilsson, A R; Wurth, W

    2012-04-01

    The soft x-ray materials science instrument is the second operational beamline at the linac coherent light source x-ray free electron laser. The instrument operates with a photon energy range of 480-2000 eV and features a grating monochromator as well as bendable refocusing mirrors. A broad range of experimental stations may be installed to study diverse scientific topics such as: ultrafast chemistry, surface science, highly correlated electron systems, matter under extreme conditions, and laboratory astrophysics. Preliminary commissioning results are presented including the first soft x-ray single-shot energy spectrum from a free electron laser. PMID:22559515

  20. Studies of ionic liquid solutions by soft X-ray absorption spectroscopy

    Microsoft Academic Search

    Fabio Rodrigues; Gustavo M. do Nascimento; Paulo S. Santos

    2007-01-01

    Soft X-ray spectroscopies give specific information about the electronic structure around light elements. The high absorption of soft X-rays by almost every molecule, including air, requires studies under vacuum, which represents a great limitation. Solids with high vapor pressure and liquids are very difficult to be studied, making solution chemistry almost neglected. This work explores the use of ionic liquids,

  1. Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-Ray (EDX) Spectroscopy

    E-print Network

    Gelfond, Michael

    system with 30 take-off angle for quantitative analysis, digital imaging, and X-ray mapping. The EDAXField Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-Ray (EDX) Spectroscopy of objective aperture. Dual SE detectors allow versatile imaging. The FE-SEM is equipped with fully digital

  2. Si/Li/ X-ray astronomical spectroscopy

    NASA Technical Reports Server (NTRS)

    Holt, S. S.

    1976-01-01

    The principles of operation of solid state nondispersive spectrometers are reviewed. Si(Li) is shown to be the preferred nondispersive X-ray spectrometer because of its inherent resolution advantages and its adaptability to the constraints and philosophy of the HEAO-B observatory. A schematic diagram is presented of the geometry of the HEAO-B solid state detector assembly as a block diagram of the primary logic mode of the HEAO-B X-ray spectrometer.

  3. X-ray chemical analysis of YBa2Cu3Ox thin film by total-reflection-angle X-ray spectroscopy

    Microsoft Academic Search

    Toshio Usui; Masayuki Kamei; Yuji Aoki; Tadataka Morishita; Shoji Tanaka

    1992-01-01

    Scanning electron microscopy and total-reflection-angle X-ray spectroscopy (SEM-TRAXS) was applied to X-ray chemical analysis of a 800 Å thick YBa2Cu3Ox (YBCO) film on an MgO substrate. In this method, the emission efficiency of characeti X-rays, excited by the electron beam of a SEM, from elements composing a thin film is drastically enhanced, as compared to that in the conventional SEM-EDX

  4. A novel instrument for quantitative nanoanalytics involving complementary X-ray methodologies

    SciTech Connect

    Lubeck, J.; Beckhoff, B.; Fliegauf, R.; Holfelder, I.; Hoenicke, P.; Mueller, M.; Pollakowski, B.; Reinhardt, F.; Weser, J. [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany)

    2013-04-15

    A novel ultra-high vacuum instrument for X-ray reflectometry and spectrometry-related techniques for nanoanalytics by means of synchrotron radiation has been constructed and commissioned. This versatile instrument was developed by the Physikalisch-Technische Bundesanstalt, Germany's national metrology institute, and includes a 9-axis manipulator that allows for an independent alignment of the samples with respect to all degrees of freedom. In addition, a rotational and translational movement of several photodiodes as well as a translational movement of an aperture system in and out of the beam is provided. Thus, the new instrument enables various analytical techniques based on energy dispersive X-ray detectors such as reference-free X-ray fluorescence analysis (XRF), total-reflection XRF, grazing-incidence XRF in addition to optional X-ray reflectometry measurements or polarization-dependent X-ray absorption fine structure analyses. With this instrument samples having a size of up to 100 mm Multiplication-Sign 100 mm can be analyzed with respect to their mass deposition, elemental or spatial composition, or the species in order to probe surface contamination, layer composition and thickness, the depth profile of matrix elements or implants, the species of nanolayers, nanoparticles or buried interfaces as well as the molecular orientation of bonds. Selected applications of this advanced ultra-high vacuum instrument demonstrate both its flexibility and capability.

  5. A HgI2 X-ray instrument for the Soviet Mars '94 mission

    NASA Astrophysics Data System (ADS)

    Economou, T. E.; Iwanczyk, J. S.; Rieder, R.

    1992-11-01

    Considerable progress has been achieved in recent years in the manufacturing and performance of ambient temperature HgI2 X-ray detectors and their associated low noise electronics, so they are now being considered for space applications. The Soviet Mars '94 is the first mission to investigate the surface and the atmosphere of the planet Mars with a complex series of instruments. An Alpha backscattering instrument with alpha, proton and X-ray modes has been proposed and selected for that mission. The X-ray mode of the instrument uses ambient temperature HgI2 X-ray detectors and low noise electronics with expected resolution of 200-250 eV FWHM at 5.9 keV. Such an instrument will obtain the detailed and complete chemical composition (except hydrogen) of the Martian surface at several sites. In the paper, the design of the X-ray flight instrument, the detectors and the low noise electronics, as well as mission operation and the expected results, will be described in detail. Laboratory performance of a HgI2 based detector system will be shown.

  6. Johann Spectrometer for High Resolution X-ray Spectroscopy

    SciTech Connect

    Machek, Pavel; Froeba, Michael [Institut fuer Anorganische und Analytische Chemie, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 58, 35392 Giessen (Germany); Welter, Edmund; Caliebe, Wolfgang; Brueggmann, Ulf [Hamburger Synchrotron Strahlungslabor (HASYLAB) am Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg (Germany); Draeger, Guenter [Martin-Luther-Universitaet Halle-Wittenberg, Fachbereich Physik, Friedemann-Bach-Platz, 06108 Halle(Saale) (Germany)

    2007-01-19

    A newly designed vacuum Johann spectrometer with a large focusing analyzer crystal for inelastic x-ray scattering and high resolution fluorescence spectroscopy has been installed at the DORIS III storage ring. Spherically bent crystals with a maximum diameter of 125 mm, and cylindrically bent crystals are employed as dispersive optical elements. Standard radius of curvature of the crystals is 1000 mm, however, the design of the mechanical components also facilitates measurements with smaller and larger bending radii. Up to four crystals are mounted on a revolving crystal changer which enables crystal changes without breaking the vacuum. The spectrometer works at fixed Bragg angle. It is preferably designed for the measurements in non-scanning mode with a broad beam spot, and offers a large flexibility to set the sample to the optimum position inside the Rowland circle. A deep depletion CCD camera is employed as a position sensitive detector to collect the energy-analyzed photons on the circumference of the Rowland circle. The vacuum in the spectrometer tank is typically 10-6 mbar. The sample chamber is separated from the tank either by 25 {mu}m thick Kapton windows, which allows samples to be measured under ambient conditions, or by two gate valves. The spectrometer is currently installed at wiggler beamline W1 whose working range is 4-10.5 keV with typical flux at the sample of 5x1010photons/s/mm2. The capabilities of the spectrometer are illustrated by resonant inelastic experiments on 3d transition metals and rare earth compounds, and by chemical shift measurements on chromium compounds.

  7. REVIEW OF SCIENTIFIC INSTRUMENTS 84, 053503 (2013) Hard x-ray tomographic studies of the destruction of an energetic

    E-print Network

    California at Los Angles, University of

    2013-01-01

    REVIEW OF SCIENTIFIC INSTRUMENTS 84, 053503 (2013) Hard x-ray tomographic studies at the Large Plasma Device to measure the spatial dis- tribution of hard x-ray (100 KeV-3 MeV) emissivity electron ring in the magnetic mirror. Hard x-rays were generated when the hot electrons struck the machine

  8. ENVIRONMENTAL AND BIOLOGICAL APPLICATIONS OF EXTENDED X-RAY ABSORPTION FINE STRUCTURE (EXAFS) AND X-RAY ABSORPTION NEAR EDGE STRUCTURE (XANES) SPECTROSCOPIES

    Microsoft Academic Search

    J. G. Parsons; M. V. Aldrich; J. L. Gardea-Torresdey

    2002-01-01

    XAS (X-ray absorption spectroscopy) has proven to be a powerful technique in several fields including the biological and environmental sciences. It has enabled scientists to analyze samples that could not be analyzed using classical techniques such as XRD (X-ray diffraction). In addition, it allows for the direct determination of elemental oxidation states, where the use of other methods is time

  9. Simulated 'On-Line' Wear Metal Analysis of Lubricating Oils by X-Ray Fluorescence Spectroscopy

    NASA Technical Reports Server (NTRS)

    Kelliher, Warren C.; Partos, Richard D.; Nelson, Irina

    1996-01-01

    The objective of this project was to assess the sensitivity of X-ray Fluorescence Spectroscopy (XFS) for quantitative evaluation of metal particle content in engine oil suspensions and the feasibility of real-time, dynamic wear metal analysis. The study was focused on iron as the majority wear metal component. Variable parameters were: particle size, particle concentration and oil velocity. A commercial XFS spectrometer equipped with interchangeable static/dynamic (flow cell) sample chambers was used. XFS spectra were recorded for solutions of Fe-organometallic standard and for a series of DTE oil suspensions of high purity spherical iron particles of 2g, 4g, and 8g diameter, at concentrations from 5 ppm to 5,000 ppm. Real contaminated oil samples from Langley Air Force Base aircraft engines and NASA Langley Research Center wind tunnels were also analyzed. The experimental data conform the reliability of XFS as the analytical method of choice for this project. Intrinsic inadequacies of the instrument for precise analytic work at low metal concentrations were identified as being related to the particular x-ray beam definition, system geometry, and flow-cell materials selection. This work supports a proposal for the design, construction and testing of a conceptually new, miniature XFS spectrometer with superior performance, dedicated to on-line, real-time monitoring of lubricating oils in operating engines. Innovative design solutions include focalization of the incident x-ray beam, non-metal sample chamber, and miniaturization of the overall assembly. The instrument would contribute to prevention of catastrophic engine failures. A proposal for two-year funding has been presented to NASA Langley Research Center Internal Operation Group (IOG) Management, to continue the effort begun by this summer's project.

  10. Electrochemical in situ reaction cell for X-ray scattering, diffraction and spectroscopy.

    PubMed

    Braun, A; Shrout, S; Fowlks, A C; Osaisai, B A; Seifert, S; Granlund, E; Cairns, E J

    2003-07-01

    A versatile electrochemical in situ reaction cell for long-term hard X-ray experiments on battery electrodes is described. Applications include the small-angle scattering, diffraction and absorption spectroscopy of lithium manganese oxide electrodes. PMID:12824932

  11. HIGH-RESOLUTION X-RAY SPECTROSCOPY OF THE MULTIPHASE INTERSTELLAR MEDIUM TOWARD Cyg X-2

    E-print Network

    Schulz, Norbert S.

    High-resolution X-ray absorption spectroscopy is a powerful diagnostic tool for probing chemical and physical properties of the interstellar medium (ISM) at various phases. We present detections of K transition absorption ...

  12. Soft x-ray emission spectroscopy studies of the electronic structure of silicon supersaturated with sulfur

    E-print Network

    Sullivan, Joseph Timothy

    We apply soft x-ray emission spectroscopy (XES) to measure the electronic structure of crystalline silicon supersaturated with sulfur (up to 0.7 at. %), a candidate intermediate-band solar cell material. Si L[subscript ...

  13. X-ray imaging crystal spectroscopy for use in plasma transport research

    E-print Network

    Bitter, M.

    This research describes advancements in the spectral analysis and error propagation techniques associated with x-ray imaging crystal spectroscopy (XICS) that have enabled this diagnostic to be used to accurately constrain ...

  14. Precision X-ray spectroscopy of 3C 273 jet knots

    E-print Network

    Avara, Mark J

    2008-01-01

    We present results from precision X-ray spectroscopy using high-resolution ([delta lambda] = 0.01A) spectra of 3C 273 jet knots extracted from eight observations made using Chandra in conjunction with the HETGS. Using these ...

  15. Analysis of chemical structure of wood charcoal by X-ray photoelectron spectroscopy

    Microsoft Academic Search

    Koei Nishimiya; Toshimitsu Hata; Yuji Imamura; Shigehisa Ishihara

    1998-01-01

    Wood charcoal carbonized at various temperatures was analyzed by X-ray photoelectron spectroscopy (XPS), Fourier-transform\\u000a infrared spectroscopy (FTIR), and X-ray diffractometry to investigate the changes of chemical structures during the carbonization\\u000a process. From the infrared spectra, the carbon double bonds and aromatic rings were seen to form at a carbonization temperature\\u000a of about 600°C. From the XPS spectra, the ratio of

  16. X-ray spectroscopy of kaonic atoms at SIDDHARTA

    NASA Astrophysics Data System (ADS)

    Cargnelli, M.; Bazzi, M.; Beer, G.; Berucci, C.; Bragadireanu, A. M.; Curceanu, C.; d'Uffizi, A.; Fiorini, C.; Ghio, F.; Guaraldo, C.; Hayano, R.; Iliescu, M.; Ishiwatari, T.; Iwasaki, M.; Levi Sandri, P.; Marton, J.; Okada, S.; Pietreanu, D.; Ponta, T.; Quaglia, R.; Romero Vidal, A.; Sbardella, E.; Scordo, A.; Shi, H.; Sirghi, D. L.; Sirghi, F.; Tatsuno, H.; Vazquez Doce, O.; Widmann, E.; Wünschek, B.; Zmeskal, J.

    2014-06-01

    The X-ray measurements of kaonic atoms play an important role for understanding the low-energy QCD in the strangeness sector. The SIDDHARTA experiment studied the X-ray transitions of 4 light kaonic atoms (H, D, 3He, and 4He) using the DAFNE electron-positron collider at LNF (Italy). Most precise values of the shift and width of the kaonic hydrogen 1s state were determined, which have been now used as fundamental information for the low-energy K-p interaction in theoretical studies. An upper limit of the X-ray yield of kaonic deuterium was derived, important for future K-d experiments. The shifts and widths of the kaonic 3He and 4He 2p states were obtained, confirming the end of the "kaonic helium puzzle". In this contribution also the plans for new experiments of kaonic deuterium are being presented.

  17. Soft X-ray emission spectroscopy of polycyclic aromatichydrocarbons

    SciTech Connect

    Muramatsu, Yasuji; Tomizawa, Kana; Denlinger, Jonathan D.; Perera, Rupert C.C.

    2004-04-02

    High-resolution CK X-ray emission spectra of polycyclicaromatic hydrocarbons (PAH) were measured using synchrotron radiation.The main peak energies in the PAH X-ray spectra shifted to a higherenergy region as the ratio of hydrogenated outer carbon atoms tothenon-hydrogenated inner carbon atoms increased. Discrete variational(DV)-Xa molecular orbital calculations provided theoretical confirmationthat the spectral features depend on the ratio ofhydrogenated/non-hydrogenated carbon atoms, which suggests that thefeatures around the main peaks provide the information of the degree ofhydrogenation in PAH compounds.

  18. Application of structural phase transitions in x-ray spectroscopy.

    PubMed

    Geppert, U

    1994-01-01

    A method is proposed for measuring different energy ranges of x-ray radiation with the same spectrometer crystal employing structural phase transitions. When the crystal temperature is varied beyond the phase transition temperature, the crystal symmetry is altered predictably and reversibly. Thus, with no change in the angle of glancing incidence, the x-ray beam hits in different crystal phases different lattice planes which correspond to different energy ranges. The advantage is that neither large motions nor exchanging the spectrometer crystal is necessary during observations. PMID:21307494

  19. The X-ray Pump-Probe instrument at the Linac Coherent Light Source.

    PubMed

    Chollet, Matthieu; Alonso-Mori, Roberto; Cammarata, Marco; Damiani, Daniel; Defever, Jim; Delor, James T; Feng, Yiping; Glownia, James M; Langton, J Brian; Nelson, Silke; Ramsey, Kelley; Robert, Aymeric; Sikorski, Marcin; Song, Sanghoon; Stefanescu, Daniel; Srinivasan, Venkat; Zhu, Diling; Lemke, Henrik T; Fritz, David M

    2015-05-01

    The X-ray Pump-Probe instrument achieves femtosecond time-resolution with hard X-ray methods using a free-electron laser source. It covers a photon energy range of 4-24?keV. A femtosecond optical laser system is available across a broad spectrum of wavelengths for generating transient states of matter. The instrument is designed to emphasize versatility and the scientific goals encompass ultrafast physical, chemical and biological processes involved in the transformation of matter and transfer of energy at the atomic scale. PMID:25931060

  20. The Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS)

    NASA Astrophysics Data System (ADS)

    Boutet, Sébastien; Williams, Garth J.

    2010-03-01

    The Linac Coherent Light Source (LCLS) became the first ever operational hard x-ray free-electron laser in 2009. It will operate as a user facility capable of delivering unique research opportunities in multiple fields of science. The LCLS and the LCLS Ultrafast Science Instruments (LUSI) construction projects are developing instruments designed to make full use of the capabilities afforded by the LCLS beam. One such instrument is being designed to utilize the LCLS coherent beam to image with high resolution any sub-micron object. This instrument is called the Coherent X-ray Imaging (CXI) instrument. This instrument will provide a flexible optical system capable of tailoring key beam parameters for the users. A suite of shot-to-shot diagnostics will also be provided to characterize the beam on every pulse. The provided instrumentation will include multi-purpose sample environments, sample delivery and a custom detector capable of collecting two-dimensional (2D) data at 120 Hz. In this paper, the LCLS will be briefly introduced, as well as the technique of coherent x-ray diffractive imaging (CXDI). A few examples of scientific opportunities arising from use of the CXI instrument will be described. Finally, the conceptual layout of the instrument will be presented, together with a description of the key requirements for the overall system and of specific devices required.

  1. The Coherent X-ray Imaging (CXI) Instrument at the Linac Coherent Light Source (LCLS)

    SciTech Connect

    Boutet, Sebastien; Williams, Garth J.; /SLAC; ,

    2011-08-16

    The Linac Coherent Light Source (LCLS) has become the first ever operational hard X-ray Free Electron Laser in 2009. It will operate as a user facility capable of delivering unique research opportunities in multiple fields of science. The LCLS and the LCLS Ultrafast Science Instruments (LUSI) construction projects are developing instruments designed to make full use of the capabilities afforded by the LCLS beam. One such instrument is being designed to utilize the LCLS coherent beam to image with high resolution any sub-micron object. This instrument is called the Coherent X-ray Imaging (CXI) instrument. This instrument will provide a flexible optical system capable of tailoring key beam parameters for the users. A suite of shot-to-shot diagnostics will also be provided to characterize the beam on every pulse. The provided instrumentation will include multi-purpose sample environments, sample delivery and a custom detector capable of collecting 2D data at 120 Hz. In this article, the LCLS will be briefly introduced along with the technique of Coherent X-ray Diffractive Imaging (CXDI). A few examples of scientific opportunities using the CXI instrument will be described. Finally, the conceptual layout of the instrument will be presented along with a description of the key requirements for the overall system and specific devices required.

  2. Fluorescence yield X-ray absorption spectroscopy for OK ? with elimination of NK ? background using superconducting tunnel junction detectors

    Microsoft Academic Search

    S. Shiki; M. Ukibe; Y. Kitajima; M. Ohkubo

    2011-01-01

    Fluorescent yield X-ray absorption fine structure (XAFS) spectroscopy is widely used for measuring chemical or physical states of particular elements in materials. A superconducting tunnel junction (STJ) detector is promising for X-ray absorption spectroscopy, especially in a soft X-ray region below 1keV, because of an excellent energy resolution of 10–20eV, which is crucial for resolving the characteristic X-ray lines from

  3. Science Instruments for the Advanced X-Ray Astrophysics Facility (AXAF)

    NASA Technical Reports Server (NTRS)

    Winkler, Carl E.; Cumings, Nesbitt P.; Randolph, Joseph L.; Talley, Drayton H.

    1993-01-01

    The AXAF program has undergone major changes since the Announcement of Opportunity was extended by NASA Headquarters in 1983. The Science Instruments (SI's) for AXAF have also experienced several design changes since they were competitively selected in 1985. Moreover, two separate complementary missions are now being baselined for AXAF; one is designated AXAF-I for imaging and will include the high precision Wolter type I optics, and the other is called AXAF-S for spectroscopy. The resulting less-costly AXAF will still be superior to any previous x-ray observatories. Both missions continue to be managed. AXAF-I contains two focal plane SI's, the High Resolution Camera (HRC), and the AXAF Charge-Coupled Device (CCD) imaging spectrometer (ACIS), as well as the High-Energy Transmission Grating Spectrometer (HETGS) and the Low-Energy Transmission Grating Spectrometer (LETGS). Optics/Cryogenics Division (BECD). AXAF-S features only one focal plane SI, the X-Ray Spectrometer (XRS). The grazing incidence mirrors for this mission are mainly to provide a large collecting area and to concentrate these x-ray photons onto the XRS detector. Precise focusing, although preferred, is of secondary importance. Nested conical foil mirrors are currently baselined; however, replicated imaging optics are being evaluated for collecting efficiency and cost. AXAF-S is scheduled to be launched in late 1999. It has been designated as an MSFC in-house project. In addition to overall management, MSFC is fully responsible for the design, development, integration, and test of the complete AXAF-S observatory, including the XRS which will be furnished by the Goddard Space Flight Center (GSFC). Together, AXAF-I and AXAF-S constitute the third of NASA's series of Great Observatories, joining the Hubble space telescope (HST) and the Gamma-Ray Observatory (GRO) which are already operational. The develop- ment, launch, and operation of the Space InfraRed Telescope Facility (SIRTF) will follow later to complete the Great Observatory series. This paper summarizes the impact these changes have had on the SI's.

  4. A novel von Hamos spectrometer for efficient X-ray emission spectroscopy in the laboratory.

    PubMed

    Anklamm, Lars; Schlesiger, Christopher; Malzer, Wolfgang; Grötzsch, Daniel; Neitzel, Michael; Kanngießer, Birgit

    2014-05-01

    We present a novel, highly efficient von Hamos spectrometer for X-ray emission spectroscopy (XES) in the laboratory using highly annealed pyrolitic graphite crystals as the dispersive element. The spectrometer covers an energy range from 2.5 keV to 15 keV giving access to chemical speciation and information about the electronic configuration of 3d transition metals by means of the K? multiplet. XES spectra of Ti compounds are presented to demonstrate the speciation capabilities of the instrument. A spectral resolving power of E/?E = 2000 at 8 keV was achieved. Typical acquisition times range from 10?min for bulk material to hours for thin samples below 1??m. PMID:24880356

  5. InFOCµS: A Balloon Instrument with <10 Arc Second Hard X-ray Imaging

    NASA Astrophysics Data System (ADS)

    Tueller, Jack; Zhang, W.; Barthelmy, S. D.; Furuzawa, A.; Haba, Y.; Krimm, H.; Kunieda, H.; Okajima, T.; Miyazawa, T.; Mushotzky, R. F.; Tamura, K.; Tawara, Y.

    2012-01-01

    The International Focusing Optics Collaboration for µCrab Sensitivity (InFOCµS) is currently funded to develop a balloon payload with a multilayer hard X-ray telescope based on slumped glass technology similar to NuSTAR, but with spatial resolution 40 times smaller PSF area than NuSTAR). The key science goal for this technology is a deep hard X-ray survey to understand role of AGN/black holes in the formation of galaxies. Due to obscuration, this can only be achieved in the hard X-ray band, where absorption is insignificant, and that only hard X-ray measurements can unambiguously determine the luminosities of individual AGN. InFOCµS will demonstrate the technology necessary to resolve the cosmic hard X-ray background and bridge the gap between NuSTAR, which can only resolve 45-65% of the background due to source confusion, and Chandra, which can detect all of the absorbed sources only at z>2. A hard X-ray survey with high spatial resolution would be a direct measurement of the luminosity function of AGN near the peak of their activity at z=0.8. We will present our approach to achieve high spatial resolution hard X-ray imaging at a cost that can be demonstrated in a balloon instrument with a resolved image of the Crab Nebula, and can be scaled to a deep-survey Explorer mission. This requires extensive refinement of the glass mirror technology at small increase in cost, higher spatial resolution focal plane detectors, and the use of techniques to achieve the extremely low background necessary for very long integration times required for a deep survey. The balloon payload will require significant improvements in pointing stability and knowledge over previous high-energy instruments to utilize the imaging capability of this telescope. InFOCµS is being prepared for a flight in the fall of 2013.

  6. X-ray imaging crystal spectroscopy for use in plasma transport research

    NASA Astrophysics Data System (ADS)

    Reinke, M. L.; Podpaly, Y. A.; Bitter, M.; Hutchinson, I. H.; Rice, J. E.; Delgado-Aparicio, L.; Gao, C.; Greenwald, M.; Hill, K.; Howard, N. T.; Hubbard, A.; Hughes, J. W.; Pablant, N.; White, A. E.; Wolfe, S. M.

    2012-11-01

    This research describes advancements in the spectral analysis and error propagation techniques associated with x-ray imaging crystal spectroscopy (XICS) that have enabled this diagnostic to be used to accurately constrain particle, momentum, and heat transport studies in a tokamak for the first time. Doppler tomography techniques have been extended to include propagation of statistical uncertainty due to photon noise, the effect of non-uniform instrumental broadening as well as flux surface variations in impurity density. These methods have been deployed as a suite of modeling and analysis tools, written in interactive data language (IDL) and designed for general use on tokamaks. Its application to the Alcator C-Mod XICS is discussed, along with novel spectral and spatial calibration techniques. Example ion temperature and radial electric field profiles from recent I-mode plasmas are shown, and the impact of poloidally asymmetric impurity density and natural line broadening is discussed in the context of the planned ITER x-ray crystal spectrometer.

  7. Broad-band soft x-ray diagnostic instruments at the LLNL Novette laser facility

    SciTech Connect

    Tirsell, K.G.; Lee, P.H.Y.; Nilson, D.G.; Medecki, H.

    1983-09-15

    Complementary broad-band instruments have been developed to measure time dependent, absolute soft x-ray spectra at the Lawrence Livermore National Laboratory (LLNL) Nd glass laser irradiation facilities. Absolute flux measurements of x rays emitted from laser-produced plasmas are important for understanding laser absorption and energy transport. We will describe two new 10-channel XRD systems that have been installed at the LLNL Novette facility for use in the 0.15- to 1.5-keV range. Since XRD channel time response is limited by available oscilloscope performance to 120 ps, a soft x-ray streak camera has been developed for better time resolution (20 ps) and greater dynamic range (approx.10/sup 3/) in the same x-ray energy region. Using suitable filters, grazing incidence mirrors, and a gold or cesium-iodide transmission cathode, this streak camera instrument has been installed at Novette to provide one broad and four relatively narrow channels. It can also be used in a single channel, spatially discriminating mode by means of pinhole imaging. The complementary nature of these instruments has been enhanced by locating them in close proximity and matching their channel energy responses. As an example of the use of these instruments, we present results from Novette 2..omega..(0.53 ..mu..m) gold disk irradiations at 1 ns and 10/sup 14/ to 10/sup 15/ W/cm/sup 2/.

  8. X-ray absorption spectroscopy of chicken sulfite oxidase crystals

    SciTech Connect

    George, G.N.; Pickering, I.J. [Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.] [Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.; Kisker, C. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Pharmacological Sciences] [State Univ. of New York, Stony Brook, NY (United States). Dept. of Pharmacological Sciences

    1999-05-17

    Sulfite oxidase catalyzes the physiologically vital oxidation of sulfite to sulfate. Recently, the crystal structure of chicken sulfite oxidase has been reported at 1.9 {angstrom} resolution. In contrast to the information available from previous X-ray absorption spectroscopic studies, the active site indicated by crystallography was a mono-oxo species. Because of this the possibility that the crystals did in fact contain a reduced molybdenum species was considered in the crystallographic work. The authors report herein an X-ray absorption spectroscopic study of polycrystalline sulfite oxidase prepared in the same manner as the previous single-crystal samples, and compare this with data for frozen solutions of oxidized and reduced enzyme.

  9. Constellation-X spectroscopy X-ray telescope (SXT)

    Microsoft Academic Search

    Robert Petre; William W. Zhang; Stephen L. O'Dell; Scott M. Owens; William A. Podgorski; Jeff Stewart; William R. Davis Jr.; Mark D. Freeman; Lester M. Cohen; Mark L. Schattenburg; Ralf K. Heilmann; Yanxia Sun; Craig R. Forest

    2003-01-01

    We provide an overview of the Constellation-X SXT development program. We describe the performance requirements and goals, and the status of the technology development program. The SXT has a 1.6-meter diameter, a 10-meter focal length, and is to have an angular resolution exceeding 15 arc seconds. It has a modular design, incorporting lightweight, multiply nested, segmented Wolter Type I x-ray

  10. High Resolution X-Ray Spectroscopy Using Microcalorimeters

    NASA Technical Reports Server (NTRS)

    Kelley, R. L.

    1997-01-01

    During the past 13 years high resolution X ray spectrometers have been developed that use cryogenically cooled microcalorimeters. These devices have inherently high signal-to-noise by operating at temperatures below 0.1 K and can achieve an energy resolution of < 10 eV over the 0.1-10 keV band. Existing devices use doped semiconductor thermometers and typically employ HgTe absorbers. The energy resolution depends on achieving a low heat capacity for the device. For soft X ray applications a relatively thin absorber (approximately 1 micrometer) may be used and an energy resolution of approximately 7 eV has been achieved. For applications up to approximately 10 keV an absorber thickness of approximately 10 micrometer is required and the energy resolution is typically approximately 12 eV. Improvements to the energy resolution in this energy band could be achieved if the problems of thermalizing X rays in low heat capacity superconductors can be overcome. The recent work on transition edge thermometers by Irwin et nl. looks particularly promising because of the higher sensitivity achievable from a sharp superconducting transition. The relatively low impedance of such a device permits the use of a low noise SQUID amplifier for readout. This would also significantly reduce the cryogen heat load compared with JFETs required by higher impedance semiconductor thermometers.

  11. Hard X-ray imaging spectroscopy of hot coronal sources and active regions with NuSTAR

    NASA Astrophysics Data System (ADS)

    Hannah, Iain; Marsh, Andrew; Glesener, Lindsay; Smith, David; Grefenstette, Brian; Madsen, Kristin; Krucker, Sam; Hudson, Hugh; White, Stephen; Shih, Albert Y.

    2015-04-01

    We present imaging spectroscopy of the Sun with the NuSTAR hard X-ray (HXR) telescope, searching for high temperature and non-thermal emission in the “non-flaring” Sun. Launched in 2012, NASA's astrophysics mission NuSTAR uses focusing optics to directly image X-rays between ~2-80 keV. In the band below ~50 keV the field of view is 12'x12' and the instrument has an energy resolution of ~0.4 keV. Although not optimized for solar observations, NuSTAR’s high sensitivity can probe previously inaccessible X-ray emission from the Sun. NuSTAR observed the Sun three times during late 2014 and we present these first directly imaged hard X-rays from non-flaring active regions. Using NuSTAR’s imaging spectroscopy capabilities we are able to derive the active region’s multi-thermal characteristics. We will also discuss a hot (>3MK) source that appears to linger high in the corona and could be associated with the occulted active region AR12192.

  12. Combined in situ X-ray absorption and diffuse reflectance infrared spectroscopy: An attractive tool for catalytic investigations

    SciTech Connect

    Marinkovic, N. S. [Synchrotron Catalysis Consortium, Univ. of Delaware, Newark, DE (United States); Wang, Q. [Synchrotron Catalysis Consortium, Univ. of Delaware, Newark, DE (United States); Barrio, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ehrlich, S. N. [National Synchrotron Light Source, Brookhaven National Lab. (BNL), Upton, NY (United States); Khalid, S. [National Synchrotron Light Source, Brookhaven National Lab. (BNL), Upton, NY (United States); Cooper, C. [Yeshiva Univ., New York, NY (United States); Frenkel, A. I. [Yeshiva Univ., New York, NY (United States)

    2011-09-01

    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.

  13. Magnetic x-ray dichroism in the spectroscopy of ultrathin magnetic alloy films

    SciTech Connect

    Tobin, J.G.; Goodman, K.W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Mankey, G.J.; Willis, R.F. [Physics Department, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)] [Physics Department, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Denlinger, J.D.; Rotenberg, E.; Warwick, A. [Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)] [Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)

    1996-07-01

    The magnetic structure of nanoscale alloy films has been probed using the magnetic x-ray linear dichroism in photoelectron spectroscopy and magnetic x-ray circular dichroism in x-ray absorption spectroscopy. FeNi and CoFe epitaxial films were grown on Cu(001), {ital in} {ital situ} and using MBE techniques. Because soft x-rays were used to probe the 2{ital p} and 3{ital p} core levels, both elemental selectivity and magnetic sensitivity were achieved simultaneously. Correlation of these magnetic techniques with compositional and structural information will be done. Ultimately, from studies such as this a complete determination of the structure-property relationships will be achievable. {copyright} {ital 1996 American Vacuum Society}

  14. Atomic structure of nickel phthalocyanine probed by X-ray absorption spectroscopy and density functional simulations

    NASA Astrophysics Data System (ADS)

    Avakyan, L. A.; Manukyan, A. S.; Mirzakhanyan, A. A.; Sharoyan, E. G.; Zubavichus, Y. V.; Trigub, A. L.; Kolpacheva, N. A.; Bugaev, L. A.

    2013-03-01

    The local atomic structure of Ni in nickel phthalocyanine was studied by K-edge X-ray absorption fine structure spectroscopy. The obtained inter atomic nickel-nitrogen distance differs from the reference X-ray diffraction data so an additional study was performed within density functional theory framework. The justification of the used theoretical approach was provided by a comparison of theoretical free electron densities of states with experimental Ni K-edge X-ray absorption near edge spectra. The refined Ni local environment retain the reference structure of the molecule except for the length of Ni-N bond which increases to 1.90 Å.

  15. Magnetic x-ray linear dichroism in the photoelectron spectroscopy of ultrathin magnetic alloy films

    SciTech Connect

    Tobin, J.G.; Goodman, K.W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Mankey, G.J.; Willis, R.F. [Physics Department University Park, Pennsylvania State University, Pennsylvania 16802 (United States)] [Physics Department University Park, Pennsylvania State University, Pennsylvania 16802 (United States); Denlinger, J.D.; Rotenberg, E.; Warwick, A. [Advanced Light Source, Lawrence Berkeley Laboratory Berkeley, California 94720 (United States)] [Advanced Light Source, Lawrence Berkeley Laboratory Berkeley, California 94720 (United States)

    1996-04-01

    The magnetic structure of nanoscale alloy films has been probed using the magnetic x-ray linear dichroism in photoelectron spectroscopy. FeNi and CoFe epitaxial films were grown on Cu(001), {ital in} {ital situ} and using molecular beam epitaxy techniques. The magnetic x-ray linear dichroism measurements were made at the Spectromicroscopy Facility of the Third Generation Advanced Light Source. Because soft x-rays were used to generate photoemission from the 3{ital p} core levels, both elemental selectivity and magnetic sensitivity were achieved simultaneously. {copyright} {ital 1996 American Institute of Physics.}

  16. What Can Be Learned from X-Ray Spectroscopy Concerning Hot Gas in the Local Bubble and Charge Exchange Processes?

    NASA Technical Reports Server (NTRS)

    Snowden, S. L.

    2008-01-01

    Both solar wind charge exchange emission and diffuse thermal emission from the Local Bubble are strongly dominated in the soft X-ray band by lines from highly ionized elements. While both processes share many of the same lines, the spectra should differ significantly due to the different production mechanisms, abundances, and ionization states. Despite their distinct spectral signatures, current and past observatories have lacked the spectral resolution to adequately distinguish between the two sources. High-resolution X-ray spectroscopy instrumentation proposed for future missions has the potential to answer fundamental questions such as whether there is any hot plasma in the Local Hot Bubble, and if so, what are the abundances of the emitting plasma and whether the plasma is in equilibrium. Such instrumentation will provide dynamic information about the solar wind including data on ion species which are currently difficult to track. It will also make possible remote sensing of the solar wind.

  17. Watching energy transfer in metalloporphyrin heterodimers using stimulated X-ray Raman spectroscopy

    PubMed Central

    Zhang, Yu; Healion, Daniel; Mukamel, Shaul

    2013-01-01

    Understanding the excitation energy transfer mechanism in multiporphyrin arrays is key for designing artificial light-harvesting devices and other molecular electronics applications. Simulations of the stimulated X-ray Raman spectroscopy signals of a Zn/Ni porphyrin heterodimer induced by attosecond X-ray pulses show that these signals can directly reveal electron–hole pair motions. These dynamics are visualized by a natural orbital decomposition of the valence electron wavepackets. PMID:24019462

  18. X-ray absorption spectroscopy studies of nickel oxide thin film electrodes for supercapacitors

    Microsoft Academic Search

    Kyung-Wan Nam; Won-Sub Yoon; Kwang-Bum Kim

    2002-01-01

    Nickel oxide films were synthesized by electrochemical precipitation of Ni(OH)2 followed by heat-treatment in air at various temperatures (200–600°C). Their structure and electrochemical properties were studied by cyclic voltammetry, X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). XRD results showed that the nickel oxide obtained at 250°C or above has a crystalline NiO structure. The specific capacitance of the oxide

  19. Soft X-ray Emission Spectroscopy at ESRF Beamline 26 Based on a Helical Undulator.

    PubMed

    Dallera, C; Puppin, E; Trezzi, G; Incorvaia, N; Fasana, A; Braicovich, L; Brookes, N B; Goedkoop, J B

    1996-09-01

    A new soft X-ray spectrograph for X-ray emission spectroscopy excited by synchrotron radiation is presented. The apparatus is now installed on beamline 26 at the ESRF in Grenoble. A brief description of the beamline is given and then several components of the spectrograph are covered in more detail. Results of experiments performed both with direct non-monochromated undulator radiation and with monochromated radiation are reported. PMID:16702684

  20. Study of silicon carbide for X-ray detection and spectroscopy

    Microsoft Academic Search

    Giuseppe Bertuccio; Roberto Casiraghi

    2003-01-01

    This work presents an analysis of silicon carbide (SiC) as semiconductor for the realization of detectors for soft X-rays (<20 keV). On the basis of experimental data on prototype SiC junctions, the performance in X-ray spectroscopy using planar diode and drift detectors in SiC have been estimated in a wide range of operating temperature (up to 150°C). It has been

  1. Prototyping a Global Soft X-ray Imaging Instrument for Heliophysics, Planetary Science, and Astrophysics Science

    NASA Technical Reports Server (NTRS)

    Collier, Michael R.; Porter, F. Scott; Sibeck, David G.; Carter, Jenny A.; Chiao, Meng P.; Chornay, Dennis J.; Cravens, Thomas; Galeazzi, Massimiliano; Keller, John W.; Koutroumpa, Dimitra; Kuntz, Kip; Read, Any M.; Robertson, Ina P.; Sembay, Steve; Snowden, Steven; Thomas, Nick

    2012-01-01

    We describe current progress in the development of a prototype wide field-of-view soft X-ray imager that employs Lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The prototype will provide proof-of-concept for a future flight instrument capable of imaging the entire dayside magnetosheath from outside the magnetosphere. Such an instrument was proposed for the FSA AXIOM mission

  2. Prototyping a Global Soft X-Ray Imaging Instrument for Heliophysics, Planetary Science, and Astrophysics Science

    NASA Technical Reports Server (NTRS)

    Collier, M. R.; Porter, F. S.; Sibeck, D. G.; Carter, J. A.; Chiao, M. P.; Chornay, D. J.; Cravens, T.; Galeazzi, M.; Keller, J. W.; Koutroumpa, D.; Kuntz, K.; Read, A. M.; Robertson, I. P.; Sembay, S.; Snowden, S.; Thomas, N.

    2012-01-01

    We describe current progress in the development of a prototype wide field-of-view soft X-ray imager that employs Lobstereye optics and targets heliophysics, planetary, and astrophysics science. The prototype will provide proof-of-concept for a future flight instrument capable of imaging the entire dayside magnetosheath from outside the magnetosphere. Such an instrument was proposed for the ESA AXIOM mission.

  3. X-ray imaging and spectroscopy using low cost COTS CMOS sensors

    NASA Astrophysics Data System (ADS)

    Lane, David W.

    2012-08-01

    Whilst commercial X-ray sensor arrays are capable of both imaging and spectroscopy they are currently expensive and this can limit their widespread use. This study examines the use of very low cost CMOS sensors for X-ray imaging and spectroscopy based on the commercial off the shelf (COTS) technology used in cellular telephones, PC multimedia and children's toys. Some examples of imaging using a 'webcam' and a modified OmniVision OV7411 sensor are presented, as well as a simple energy dispersive X-ray detector based on an OmniVision OV7221 sensor. In each case X-ray sensitivity was enabled by replacing the sensor's front glass window with a 5 ?m thick aluminium foil, with X-rays detected as an increase in a pixel's dark current due to the generation of additional electron-hole pairs within its active region. The exposure control and data processing requirements for imaging and spectroscopy are discussed. The modified OV7221 sensor was found to have a linear X-ray energy calibration and a resolution of approximately 510 eV.

  4. Investigation of surface structure with X-ray absorption and electron emission spectroscopies

    NASA Astrophysics Data System (ADS)

    Pauli, Mark Daniel

    The use of electron spectromicroscopy for the study of the chemical composition and electronic properties of surfaces, overlayers, and interfaces has become widely accepted. Improvements to the optics of instruments such as the X-ray photo electron emission microscope have pushed spectroscopic microscopies into the realm of very high spatial resolution, at and below 1 micrometer [1]. Coupled with the high spectral resolution available from third generation synchrotron sources, this spatial resolution allows the measurement of micro-X-ray absorption near-edge spectra in addition to the more typical electron emission spectra and diffraction patterns. Complementary to the experimental developments is the development of improved theoretical methods for computational modeling of X-ray absorption and emission spectroscopies. In the field of tribochemistry, zinc dialkyl dithiophosphate (ZDDP) has long been a topic of much study. ZDDP is widely used as an anti-wear additive in engine oils and there is interest in determining the decomposition products of ZDDP that provide this protection against friction. An analysis of X-ray absorption near-edge spectra of thermal films from ZDDP samples is presented, including a comparison of the Zinc L-edge spectra with model calculations [2]. It was found essential to carry out self-consistent calculations of the electronic structure for the modeling. For the techniques of electron diffraction, a new method for a full multiple-scattering calculation of diffraction patterns from crystals with two-dimensional periodicity parallel to the surface is presented [3]. The calculation makes use of Helmholtz's reciprocity principle to compute the path-reversed process of the back propagation of a photoelectron from the position of a distant detector to that of the emitting atom. Early application is demonstrated with simulations of 64 eV M2,3VV and 914 eV L 2,3VV Auger electron diffraction from a Cu(001) surface. The functionality of the path-reversed calculation is greatly increased by extension to photoelectron diffraction for crystal surfaces with many atoms per unit cell [4]. The results are essentially indistinguishable from those of a conventional forward-path calculation. Application to photoelectron diffraction for 955 eV O 1s emission from a MgO(001) surface shows good agreement with experiment.

  5. Applications of X-ray absorption spectroscopy to biologically relevant metal-based chemistry

    NASA Astrophysics Data System (ADS)

    Best, Stephen P.; Cheah, Mun Hon

    2010-02-01

    Recent developments in the understanding of the biosynthesis of the active site of the nitrogenase enzyme, the structure of the iron centre of [Fe]-hydrogenase and the structure and biomimetic chemistry of the [FeFe] hydrogenase H-cluster as deduced by application of X-ray spectroscopy are reviewed. The techniques central to this work include X-ray absorption spectroscopy either in the form of extended X-ray absorption fine structure (EXAFS), X-ray absorption near-edge structure (XANES) and nuclear resonant vibrational spectroscopy (NRVS). Examples of the advances in the understanding of the chemistry of the system through integration of a range of spectroscopic and computational techniques with X-ray spectroscopy are highlighted. The critical role played by ab initio calculation of structural and spectroscopic properties of transition-metal compounds using density functional theory (DFT) is illustrated both by the calculation of nuclear resonance vibrational spectroscopy (NRVS) spectra and the structures and spectra of intermediates through the catalytic reactions of hydrogenase model compounds.

  6. Note: Application of a pixel-array area detector to simultaneous single crystal x-ray diffraction and x-ray absorption spectroscopy measurements

    SciTech Connect

    Sun, Cheng-Jun, E-mail: cjsun@aps.anl.gov; Brewe, Dale L.; Heald, Steve M. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Zhang, Bangmin [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore (Singapore); NUSNNI-Nanocore, National University of Singapore, 117411 Singapore (Singapore); Chen, Jing-Sheng; Chow, G. M. [Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore (Singapore)] [Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore (Singapore); Venkatesan, T. [NUSNNI-Nanocore, National University of Singapore, 117411 Singapore (Singapore) [NUSNNI-Nanocore, National University of Singapore, 117411 Singapore (Singapore); Department of Physics, National University of Singapore, 117542 Singapore (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, 117575 Singapore (Singapore)

    2014-04-15

    X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are two main x-ray techniques in synchrotron radiation facilities. In this Note, we present an experimental setup capable of performing simultaneous XRD and XAS measurements by the application of a pixel-array area detector. For XRD, the momentum transfer in specular diffraction was measured by scanning the X-ray energy with fixed incoming and outgoing x-ray angles. By selecting a small fixed region of the detector to collect the XRD signal, the rest of the area was available for collecting the x-ray fluorescence for XAS measurements. The simultaneous measurement of XRD and X-ray absorption near edge structure for Pr{sub 0.67}Sr{sub 0.33}MnO{sub 3} film was demonstrated as a proof of principle for future time-resolved pump-probe measurements. A static sample makes it easy to maintain an accurate overlap of the X-ray spot and laser pump beam.

  7. X-ray spectroscopy of the SSME plume

    NASA Technical Reports Server (NTRS)

    Olive, Dan F.

    1988-01-01

    In order to examine the potential of using SSME exhaust plume radiation in the soft X-ray spectrum as an early warning system of imminent engine failure, a low cost, low risk experiment was devised. An approach was established, equipment was leased, the system was installed and checked out, and data were successfully acquired demonstrating the proof-of-concept. One spectrum measurement of the SSME plume was acquired during a 300 second burn on the A-1 Test Stand. This spectrum showed a prominent, line emission feature at about 34.5 KeV, a result which was not expected, nor can it be explained at this time. If X-ray spectra are to be useful as a means of monitoring nominal engine operation, it will be necessary to explore this region of the EM spectrum in greater detail. The presence of structure in the spectrum indicates that this technology may prove to be useful as an engine health monitoring system.

  8. X-Ray Diffraction and Fluorescence Measurements for In-situ Planetary Instruments

    NASA Astrophysics Data System (ADS)

    Hansford, G.; Hill, K. S.; Vernon, D.; Ambrosi, R. M.; Bridges, J.; Hutchinson, I.

    2010-12-01

    The X-Ray Diffraction (XRD) instruments are core components of the forthcoming NASA Mars Science Laboratory (MSL) and ESA/NASA EXOMARS missions and will provide the first demonstrations of an XRF/XRD instrument’s capabilities in-situ on an extraterrestrial planetary surface. The University of Leicester team is part of the Italy-UK collaboration that is responsible for building the ExoMars X-Ray Diffraction instrument, Mars XRD. The ExoMars X-ray diffraction instrument incorporates an 55-Fe radioisotope source and three fixed-position CCDs to simultaneously acquire an X-Ray fluorescence spectrum and a diffraction pattern providing a measurement of both elemental and mineralogical composition [1]. The CCDs cover an angular range from 6 to 65-deg enabling the analysis of silicates, from clays, or other phyllosilicates characterised by varying d-spacings, to oxides, and carbonates or evaporites. The identification of hydrous minerals may help identify past Martian hydrothermal systems capable of preserving traces of life. Here we present some initial findings from XRF and XRD tests carried out at the University of Leicester using an 55-Fe source and X-ray sensitive CCD [1]. The XRD/XRD test system consists of a single CCD on a motorised arm, an 55-Fe X-ray source, source collimator and a sample table which approximately replicate the reflection geometry of the XRD instrument. It was used to test geological reference standard materials and Martian analogues. Incidence angle and CCD angles on both the diffraction and fluorescence results were evaluated. A key area of interest is the effect of sample roughness on the XRD/XRF results. We present results from testing pressed powder pellet samples of varying surface roughness, and a comparison with model results [2]. So far we have found that increased roughness causes a reduced intensity at lower take-off angles. Several methods for measuring surface roughness of the samples have been used including an Alicona Infinite Focus microscope. [1] Marinangeli et al. (2007) LPSC #1322 [2] Hansford et al. (2010) EGU General Assembly 2010

  9. High-Resolution Structure of the Photosynthetic Mn4Ca Catalyst From X-Ray Spectroscopy

    SciTech Connect

    Yano, J.; Kern, J.; Pushkar, Y.; Sauer, K.; Glatzel, P.; Bergmann, U.; Messinger, J.; Zouni, A.; Yachandra, V.K.; /LBL, Berkeley /ESRF, Grenoble /SLAC, SSRL /Max Planck Inst., Mulheim

    2009-04-30

    The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn{sub 4}Ca cluster, is described. Issues of X-ray damage, especially at the metal sites in the Mn{sub 4}Ca cluster, are discussed. The structure of the Mn{sub 4}Ca catalyst at high resolution, which has so far eluded attempts of determination by X-ray diffraction, X-ray absorption fine structure (EXAFS) and other spectroscopic techniques, has been addressed using polarized EXAFS techniques applied to oriented photosystem II (PSII) membrane preparations and PSII 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{beta} emission) have been used earlier to determine the oxidation states of the Mn{sub 4}Ca cluster, and in this report we review the use of X-ray resonant Raman spectroscopy to understand the electronic structure of the Mn{sub 4}Ca cluster as it cycles through the intermediate S-states.

  10. Ultra-soft x-ray absorption spectroscopy: A bulk and surface probe of materials

    SciTech Connect

    Fischer, D.A. (National Institute of Standards and Technology, Gaithersburg, MD (United States)); Mitchell, G.E.; Dekoven, B.M. (Dow Chemical Co., Midland, MI (United States)); Yeh, A.T.; Gland, J.L. (Michigan Univ., Ann Arbor, MI (United States)); Moodenbaugh, A.R. (Brookhaven National Lab., Upton, NY (United States))

    1993-01-01

    Direct comparisons between surface and bulk of diverse materials can be made by simultaneous electron yield (5 nm depth sensitivity) and fluorescence yield (200 nm) ultra soft x-ray absorption spectroscopy measurements utilizing a rapid sample interchange apparatus. For example the orientations of functional groups have been characterized at and near the surface of a series of model polymeric materials highlighting the chemical and molecular sensitivity of ultra soft x-ray absorption spectroscopy. In addition we discuss a bulk sensitive use of fluorescence yield to non destructively study a buried metal polymer interface. A second bulk sensitive example is the use of fluorescence yield oxygen K near edge x-ray spectroscopy as a method to determine the hole state density of high Tc materials.

  11. Ultra-soft x-ray absorption spectroscopy: A bulk and surface probe of materials

    SciTech Connect

    Fischer, D.A. [National Institute of Standards and Technology, Gaithersburg, MD (United States); Mitchell, G.E.; Dekoven, B.M. [Dow Chemical Co., Midland, MI (United States); Yeh, A.T.; Gland, J.L. [Michigan Univ., Ann Arbor, MI (United States); Moodenbaugh, A.R. [Brookhaven National Lab., Upton, NY (United States)

    1993-06-01

    Direct comparisons between surface and bulk of diverse materials can be made by simultaneous electron yield (5 nm depth sensitivity) and fluorescence yield (200 nm) ultra soft x-ray absorption spectroscopy measurements utilizing a rapid sample interchange apparatus. For example the orientations of functional groups have been characterized at and near the surface of a series of model polymeric materials highlighting the chemical and molecular sensitivity of ultra soft x-ray absorption spectroscopy. In addition we discuss a bulk sensitive use of fluorescence yield to non destructively study a buried metal polymer interface. A second bulk sensitive example is the use of fluorescence yield oxygen K near edge x-ray spectroscopy as a method to determine the hole state density of high Tc materials.

  12. X-ray Spectroscopy for Quality Control of Chemotherapy Drugs

    SciTech Connect

    Greaves, E. D.; Barros, H.; Bermudez, J.; Sajo-Bohus, L. [Universidad Simon Bolivar, Apartado 89000, Caracas 1080A (Venezuela); Angeli-Greaves, M. [Universidad Central de Venezuela, Apartado 90373 Caracas 1083A (Venezuela)

    2007-10-26

    We develop a method, employing Compton peak standardization and the use of matrix-matched spiked samples with Total Reflection X-ray Fluorescence (TXRF), for the determination of platinum plasma concentrations of patients undergoing chemotherapy with Pt-bearing drugs. Direct blood plasma analysis attains Pt detection limits of 70 ng/ml. Measurement results of prescribed drug doses are compared to achieved blood Pt concentrations indicating a lack of expected correlations. Direct analysis of Pt-containing infused drugs from a variety of suppliers indicates cases of abnormal concentrations which raises quality control issues. We demonstrate the potential usefulness of the method for pharmacokinetic studies or for routine optimization and quality control of Pt chemotherapy treatments.

  13. A Laboratory Scale Critical-Dimension Small-Angle X-ray Scattering Instrument

    SciTech Connect

    Ho, Derek L.; Wang Chengqing; Lin, Eric K.; Jones, Ronald L.; Wu Wenli [Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8541 (United States)

    2007-09-26

    New methods for critical dimension (CD) measurements may be needed to enable the detailed characterization of nanoscale structures produced in the semiconductor industry and for nanotechnology applications. In earlier work, small angle x-ray scattering (SAXS) measurements with synchrotron sources have shown promise in meeting several grand challenges for CD metrology. However, it is not practical to depend upon x-ray synchrotron sources, which are large national facilities with limitations in the number of available instruments. To address this problem, a laboratory scale SAXS instrument for critical dimension measurements on periodic nanoscale patterns has been designed, installed, and tested. The system possesses two configurations, SAXS and ultra-small-angle x-ray scattering (USAXS), with a radiation target of either copper or molybdenum. With these configurations, the instrument is capable of accessing scattering angles that probe length scales ranging from ca. 0.5 nm to 2 {mu}m. In this work, we compare CD-SAXS measurements taken from a synchrotron-based SAXS at the Advanced Photon Source of the Argonne National Laboratory with those from the National Institute of Standards and Technology laboratory-scale SAXS instrument. The results from standard line/space gratings possessing periodic line-space patterns with CDs of tens to hundreds of nanometers show that the laboratory-scale system can quantitatively measure parameters, such as the pitch, line width, height, line-width roughness and sidewall angle. These results show that laboratory-scale measurements are feasible and can be used for research and development purposes or to assist calibration of optical scatterometry and CD-scanning electron microscopy instruments. The primary limitation of the measurement is that the data collection rate is unacceptably slow for production metrology because of the significantly lower x-ray beam fluxes currently available.

  14. A Laboratory Scale Critical-Dimension Small-Angle X-ray Scattering Instrument

    NASA Astrophysics Data System (ADS)

    Ho, Derek L.; Wang, Chengqing; Lin, Eric K.; Jones, Ronald L.; Wu, Wen-Li

    2007-09-01

    New methods for critical dimension (CD) measurements may be needed to enable the detailed characterization of nanoscale structures produced in the semiconductor industry and for nanotechnology applications. In earlier work, small angle x-ray scattering (SAXS) measurements with synchrotron sources have shown promise in meeting several grand challenges for CD metrology. However, it is not practical to depend upon x-ray synchrotron sources, which are large national facilities with limitations in the number of available instruments. To address this problem, a laboratory scale SAXS instrument for critical dimension measurements on periodic nanoscale patterns has been designed, installed, and tested. The system possesses two configurations, SAXS and ultra-small-angle x-ray scattering (USAXS), with a radiation target of either copper or molybdenum. With these configurations, the instrument is capable of accessing scattering angles that probe length scales ranging from ca. 0.5 nm to 2 ?m. In this work, we compare CD-SAXS measurements taken from a synchrotron-based SAXS at the Advanced Photon Source of the Argonne National Laboratory with those from the National Institute of Standards and Technology laboratory-scale SAXS instrument. The results from standard line/space gratings possessing periodic line-space patterns with CDs of tens to hundreds of nanometers show that the laboratory-scale system can quantitatively measure parameters, such as the pitch, line width, height, line-width roughness and sidewall angle. These results show that laboratory-scale measurements are feasible and can be used for research and development purposes or to assist calibration of optical scatterometry and CD-scanning electron microscopy instruments. The primary limitation of the measurement is that the data collection rate is unacceptably slow for production metrology because of the significantly lower x-ray beam fluxes currently available.

  15. X-ray spectroscopy characterization of azobenzene-functionalized triazatriangulenium adlayers on Au(111) surfaces.

    PubMed

    Ulrich, Sandra; Jung, Ulrich; Strunskus, Thomas; Schütt, Christian; Bloedorn, Andreas; Lemke, Sonja; Ludwig, Eric; Kipp, Lutz; Faupel, Franz; Magnussen, Olaf; Herges, Rainer

    2015-06-24

    Triazatriangulenium (TATA) platform molecules allow the preparation of functionalized surfaces with well-defined lateral spacings of freestanding functional groups. Using scanning tunneling microscopy, synchrotron-based X-ray photoelectron spectroscopy, near edge X-ray absorption fine structure spectroscopy and complementary density functional theory calculations the chemical composition and orientational order of adlayers of functionalized azobenzene containing TATA platform molecules were characterized. According to these studies the molecules are chemically intact on the surface after self-assembly from solution and exhibit a well-defined adsorption geometry where the azobenzene units are oriented almost perpendicular to the surface. PMID:26063248

  16. Imaging X-ray Thomson Scattering Concept for the Matter in Extreme Conditions Instrument at LCLS

    NASA Astrophysics Data System (ADS)

    Montgomery, D. S.; Gamboa, E. J.

    2010-11-01

    The Linac Coherent Light Source at SLAC, an x-ray free electron laser tunable in the range 800 -- 8000 eV, with 2 x 10^12 photons in a 200 fsec pulse, is a revolutionary facility that will impact many fields of science, including high energy density (HED) laboratory plasmas. The Matter in Extreme Conditions (MEC) instrument at LCLS will use high-power lasers to create HED plasmas, and will use the XFEL with various diagnostics to probe these conditions. One proposed use of the LCLS-MEC is to perform Thomson scattering in dense plasmas using the x-ray laser as a probe. Recent experiments at LANL's Trident Laser demonstrate the ability to measure spatial profiles of dense plasma conditions using a laser-plasma x-ray source, together with a high-efficiency, high-resolution imaging spectrometer, to perform imaging x-ray Thomson scattering. Here we propose an imaging spectrometer design, with <20-?m resolution, that will provide profiles of density, temperature, and ionization state in near-solid-density plasmas with a 8 keV probe at the LCLS-MEC, and propose an initial experimental design to examine shocks in near-solid-density plasmas.

  17. Ab initio simulation of diffractometer instrumental function for high-resolution X-ray diffraction1

    PubMed Central

    Mikhalychev, Alexander; Benediktovitch, Andrei; Ulyanenkova, Tatjana; Ulyanenkov, Alex

    2015-01-01

    Modeling of the X-ray diffractometer instrumental function for a given optics configuration is important both for planning experiments and for the analysis of measured data. A fast and universal method for instrumental function simulation, suitable for fully automated computer realization and describing both coplanar and noncoplanar measurement geometries for any combination of X-ray optical elements, is proposed. The method can be identified as semi-analytical backward ray tracing and is based on the calculation of a detected signal as an integral of X-ray intensities for all the rays reaching the detector. The high speed of calculation is provided by the expressions for analytical integration over the spatial coordinates that describe the detection point. Consideration of the three-dimensional propagation of rays without restriction to the diffraction plane provides the applicability of the method for noncoplanar geometry and the accuracy for characterization of the signal from a two-dimensional detector. The correctness of the simulation algorithm is checked in the following two ways: by verifying the consistency of the calculated data with the patterns expected for certain simple limiting cases and by comparing measured reciprocal-space maps with the corresponding maps simulated by the proposed method for the same diffractometer configurations. Both kinds of tests demonstrate the agreement of the simulated instrumental function shape with the measured data. PMID:26089760

  18. Mode-Locked Multichromatic X-Rays in a Seeded Free-Electron Laser for Single-Shot X-Ray Spectroscopy

    SciTech Connect

    Xiang, Dao; Ding, Yuantao; Raubenheimer, Tor; Wu, Juhao; /SLAC

    2012-05-10

    We present the promise of generating gigawatt mode-locked multichromatic x rays in a seeded free-electron laser (FEL). We show that, by using a laser to imprint periodic modulation in electron beam phase space, a single-frequency coherent seed can be amplified and further translated to a mode-locked multichromatic output in an FEL. With this configuration the FEL output consists of a train of mode-locked ultrashort pulses which span a wide frequency gap with a series of equally spaced sharp lines. These gigawatt multichromatic x rays may potentially allow one to explore the structure and dynamics of a large number of atomic states simultaneously. The feasibility of generating mode-locked x rays ranging from carbon K edge ({approx}284 eV) to copper L{sub 3} edge ({approx}931 eV) is confirmed with numerical simulation using the realistic parameters of the linac coherent light source (LCLS) and LCLS-II. We anticipate that the mode-locked multichromatic x rays in FELs may open up new opportunities in x-ray spectroscopy (i.e. resonant inelastic x-ray scattering, time-resolved scattering and spectroscopy, etc.).

  19. X-ray photon correlation spectroscopy studies of surfaces and thin films.

    PubMed

    Sinha, Sunil K; Jiang, Zhang; Lurio, Laurence B

    2014-12-10

    The technique of X-ray Photon Correlation Spectroscopy (XPCS) is reviewed as a method for studying the relatively slow dynamics of materials on time scales ranging from microseconds to thousands of seconds and length scales ranging from microns down to nanometers. We focus on the application of this technique to study dynamical fluctuations of surfaces, interfaces and thin films. We first discuss instrumental issues such as the effects of partial coherence (or alternatively finite instrumental resolution) and optimization of signal-to-noise ratios in the experiments. We then review what has been learned from recent XPCS studies of capillary wave fluctuations on liquid surfaces and polymer films, of nanoparticles used as probes to study the interior dynamics of polymer films, of liquid crystals and multilamellar surfactant films, and of metal surfaces, and magnetic domain wall fluctuations in antiferromagnets. We then discuss studies of non-equilibrium dynamics described by 2-time correlation functions. Finally, we briefly speculate on possible future XPCS experiments at new synchrotron sources currently under development including studies of dynamics on time scales down to femtoseconds. PMID:25236339

  20. FORTRAN program for x ray photoelectron spectroscopy data reformatting

    NASA Technical Reports Server (NTRS)

    Abel, Phillip B.

    1989-01-01

    A FORTRAN program has been written for use on an IBM PC/XT or AT or compatible microcomputer (personal computer, PC) that converts a column of ASCII-format numbers into a binary-format file suitable for interactive analysis on a Digital Equipment Corporation (DEC) computer running the VGS-5000 Enhanced Data Processing (EDP) software package. The incompatible floating-point number representations of the two computers were compared, and a subroutine was created to correctly store floating-point numbers on the IBM PC, which can be directly read by the DEC computer. Any file transfer protocol having provision for binary data can be used to transmit the resulting file from the PC to the DEC machine. The data file header required by the EDP programs for an x ray photoelectron spectrum is also written to the file. The user is prompted for the relevant experimental parameters, which are then properly coded into the format used internally by all of the VGS-5000 series EDP packages.

  1. The determination of local structural units in amorphous SiBN(3)C by means of X-ray photoelectron and X-ray absorption spectroscopy.

    PubMed

    Franke, R; Bender, S; Arzberger, I; Hormes, J; Jansen, M; Jüngermann, H; Löffelholz, J

    1996-03-01

    X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) spectroscopy at the K-edge of Si, N, and B are presented as techniques suited to determine structural units in amorphous SiBN(3)C. The measurements reported give evidence for the presence of tetrahedral (SiN(4))- and planar (BN(3))-groups. It is concluded that these structural elements dominate the atomic surroundings of B and Si, respectively. From the spectroscopic results we conclude that C is mainly bonded to N and is not present as a pure carbide. PMID:15048406

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

    SciTech Connect

    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.

  3. X-Ray Absorption Spectroscopy Determination of Oxidation States

    NASA Astrophysics Data System (ADS)

    Bajt, S.; Sutton, S. R.; Smith, J. V.

    1993-07-01

    Introduction: The oxidation state of minor and trace elements in minerals from planetary materials can be used to directly probe the oxygen fugacity of the environment from which the minerals formed. For example, on the basis of existing oxygen fugacity determinations it has been suggested that the parent bodies of chondrites were > 30 km in diameter [1]. Petrogenetic models generally assume oxygen fugacities based on indirect evidence. The x-ray microprobe offers the capability to determine oxidation states for a large suite of elements in individual coexisting phases in conventional rock thin sections using the microXANES (X-ray Absorption Near Edge Structure) technique. Recent Results: Initial research has concentrated on transition metals particularly Cr. The results on Cr oxidation state for olivine and pyroxene from mare basalts 15555 [2] showed that olivine contains predominately divalent Cr while pyroxene accommodates Cr mainly in trivalent state. Similar results for olivine from kimberlitic diamonds showed a mixture of the two states [3]. These results suggest that the terrestrial olivine crystallized in a more oxidizing environment than the lunar olivine and that divalent chromium is a ubiquitous component of olivine crystallized under reducing conditions. Calibration of the method in terms of oxygen fugacity requires the analysis of synthetic olivine crystallized from melts of appropriate composition at controlled fO(sub)2 [4]. MicroXANES analyses of Fe surprisingly suggested that Fe in plagioclase from lunar anorthosite 15415 is more oxidized than that in plagioclase from Stillwater anorthosites and shergottites [5]. Recently, iron oxide specimens were analyzed, specifically, magnetite (Fe3O4), hematite (Fe2O3) and altered magnetites (i.e., magnetites suspected of containing substantial alteration to hematite). The results showed that the altered magnetites are roughly equal mixtures of magnetite and hematite [6]. Future Research: The work on lunar olivines in lunar basalts is being extended to lunar olivines in highlands rocks. Oxygen fugacities of the early lunar magmas will be compared with those of the latter mare systems. Determinations of Cr oxidation state in olivine from carbonaceous meteorites are also being pursued but the Cr content of olivine from primitive meteorites is close to current detection limit with microXANES (about 10 ppm). MicroXANES will also provide valuable information on the oxidation states of transition elements in primitive interplanetary dust particles (IDPs). Preliminary results on one IDP indicated that Fe was in both the divalent and trivalent states and the shape of the spectrum is inconsistent with an oxide host. This technique will also be useful in estimating magnetite content in heated IDPs. Iron oxidation states of SNC meteorites and other achondrites will be valuable in constraining the oxygen fugacity of igneous planetary systems. Measurements of Ti^3+, Ti^4+, V^2+ and V^3+ in the constituent phases of CAIs will help to constrain the chemical history of materials that formed in the early solar nebula. The next generation synchrotron source, the Advanced Photon Source at Argonne National Laboratory, will be available for use by planetary scientists in 1996 and will extend these techniques to 1 ppm detection limits and 1 micrometer spatial resolution. References: [1] Rubin A. E. et al. (1988) In Meteorites and the Early Solar System, 488-511. [2] Sutton S. R. et al. (1993) GCA, 57-2, 461-468. [3] Sutton S. R. et al. (1993) LPS XXIV, 1383- 1384. [4] Hanson B. Z. and Delano J. W. (1992) LPS XXIII, 481- 482. [5] Delaney J. S. et al. (1992) LPS XXIII, 299-300. [6] Sutton S. R. et al. (1993) LPS XXIV, 1385-1386.

  4. Application of x-ray absorption spectroscopy to the study of corrosion and inhibition

    SciTech Connect

    Davenport, A.J.; Isaacs, H.S.

    1991-01-01

    X-ray absorption spectroscopy is a powerful technique for determination of valency and coordination. Measurements can be made in air or in situ under electrochemical control. The technique will be described and its application to the analysis of passive oxide films, corrosion products, and inhibitors will be reviewed.

  5. Highly Sensitive Nitric Oxide Detection Using X-ray Photoelectron Spectroscopy

    E-print Network

    Schwartz, Jeffrey

    explosives3 so detection of trace amounts of explosive, for example in security screening, also requiresHighly Sensitive Nitric Oxide Detection Using X-ray Photoelectron Spectroscopy Manish Dubey, Steven and direct detection of NO at these levels is important. NO is also a decomposition product of several

  6. X-ray absorption spectroscopy of biomimetic dye molecules for solar cells Peter L. Cook,1

    E-print Network

    Himpsel, Franz J.

    X-ray absorption spectroscopy of biomimetic dye molecules for solar cells Peter L. Cook,1 Xiaosong November 2009 Dye-sensitized solar cells are potentially inexpensive alternatives to traditional semiconductor solar cells. In order to optimize dyes for solar cells we systematically investigate

  7. Passive Spectroscopy Bolometers, Grating- And X-Ray Imaging Crystal Spectrometers

    SciTech Connect

    Bitter, M; Hill, K W; Scott, S; Paul, S; Ince-Cushmann, A; Reinke, M; Rice, J; Beiersdorfer, P; Gu, M F; Lee, S G; Broennimann, C; Eikenberry, E F

    2007-11-07

    This tutorial gives a brief introduction into passive spectroscopy and describes the working principles of bolometers, a high-resolution grating spectrometer, and a novel X-ray imaging crystal spectrometer, which is of particular interest for profile measurements of the ion temperature and plasma rotation velocity on ITER and future burning plasma experiments.

  8. Structural Characterization of Mixed Nanoferrites Using X-Ray Absorption Spectroscopy

    Microsoft Academic Search

    S. Calvin; B. Ravel; E. A. Carpenter; S. A. Morrison; V. G. Harris

    2002-01-01

    Structural characterization of mixed nanoferrite materials is often difficult, both because of the high degree of disorder which may be present and because the transition metals which are common constituents of these materials, such as manganese, iron, nickel, and zinc, exhibit similar atomic scattering factors. Extended x-ray absorption fine structure (EXAFS) spectroscopy is well-suited for investigation of these materials, since

  9. Picosecond x-ray absorption spectroscopy of photochemical transient species in solution

    SciTech Connect

    Schoenlein, Robert William; Khalil, Munira; Marcus, Matthew A.; Smeigh, Amanda L.; McCusker, James K.; Chong, Henry H.W.; Schoenlein, Robert W.

    2006-08-07

    A photoinduced Fe(II) spin crossover reaction in solution is studied with ultrafast x-ray absorption spectroscopy. The iron-nitrogen bond lengthens by 0.21+-0.03 Angstrom in the high-spin transient excited state relative to the ground state.

  10. Application of Wavelet Transform to Extended X-ray Absorption Spectroscopy

    Microsoft Academic Search

    H. FUNKE; M. CHUKALINA; A. C. SCHEINOST

    2007-01-01

    A new application of continuous wavelet transform to the data analysis of extended x- ray absorption spectroscopy is presented. The wavelet transform provides not only radial distance resolution of the spectra, but resolves also the wave vector space permitting the discrimination of atoms by their elemental nature. This resolution is especially important if these atoms are at the same distance.

  11. X-ray photoelectron spectroscopy and spectral transmittance study of stoichiometry in sputtered vanadium oxide films

    Microsoft Academic Search

    M. Ghanashyam Krishna; Y. Debauge; A. K. Bhattacharya

    1998-01-01

    The growth of magnetron sputtered vanadium oxide thin films has been investigated by means of X-ray photoelectron spectroscopy and spectral transmittance in the region from 350 to 1100 nm. It is shown that films stoichiometry is dependent on film thickness as well as oxygen partial pressure. Beyond a critical thickness of ? 250 nm, the films are completely stoichiometric V2O5

  12. Sulphur speciation of leached chalcopyrite surfaces as determined by X-ray photoelectron spectroscopy

    Microsoft Academic Search

    Craig Klauber; Andrew Parker; Wilhelm van Bronswijk; Helen Watling

    2001-01-01

    A key factor in improving the bioleaching route for chalcopyrite processing is a better understanding of the surface speciation that exists under chemical leaching conditions that mimic the acid bioleach. The surface sulphur speciation of chalcopyrite under such conditions has been revisited using X-ray photoelectron spectroscopy (XPS). Objectives of the study were to resolve the issue of possible passivation candidates

  13. An X-ray photoelectron spectroscopy study of the mechanism of oxidative dissolution of chalcopyrite

    Microsoft Academic Search

    A. Parker; C. Klauber; A. Kougianos; H. R. Watling; W. van Bronswijk

    2003-01-01

    An alternative mechanism based on the application of simple chemical principles involving hydrated (hence realistic) solution species is proposed for the oxidative acid leaching of copper and iron from chalcopyrite. The consistent surface speciation for abiotic and microbial, aerobic and anaerobic conditions fits with the need for a common mechanism. X-ray photoelectron spectroscopy detected the expected sulphur and sulphate surface

  14. Stereochemistry Determination by Powder X-ray Diffraction Analysis and NMR Spectroscopy Residual Dipolar Couplings

    SciTech Connect

    Garcia, M.; Pagola, S; Navarro-Vasquez, A; Phillips, D; Gayathri, C; Krakauer, H; Stephens, P; Nicotra, V; Gil, R

    2009-01-01

    A matter of technique: For a new steroidal lactol, jaborosalactol 24 (1), isolated from Jaborosa parviflora, NMR spectroscopy residual dipolar couplings and powder X-ray diffraction analysis independently gave the same stereochemistry at C23-C26. Conventional NMR spectroscopic techniques, such as NOE and {sup 3}J coupling-constant analysis failed to unambiguously determine this stereochemistry.

  15. Detection, identification and mapping of iron anomalies in brain tissue using X-ray absorption spectroscopy

    Microsoft Academic Search

    A. Mikhaylova; M. Davidson; H. Toastmann; J. E. T. Channell; Y. Guyodo; C. Batich; J. Dobson

    2005-01-01

    This work describes a novel method for the detection, identification and mapping of anomalous iron compounds in mammalian brain tissue using X-ray absorption spectroscopy. We have located and identified individual iron anomalies in an avian tissue model associated with ferritin, biogenic magnetite and haemoglobin with a pixel resolution of less than 5 mm. This technique represents a breakthrough in the

  16. Detection, identification and mapping of iron anomalies in brain tissue using X-ray absorption spectroscopy

    Microsoft Academic Search

    A. Mikhaylova; M. Davidson; H. Toastmann; J. E. T. Channell; Y. Guyodo; C. Batich; J. Dobson

    2008-01-01

    This work describes a novel method for the detection, identification and mapping of anomalous iron compounds in mammalian brain tissue using X-ray absorption spectroscopy. We have located and identified individual iron anomalies in an avian tissue model associated with ferritin, biogenic magnetite and haemoglobin with a pixel resolution of less than 5 μm. This technique represents a breakthrough in the

  17. X-ray line spectroscopy method for magnetic field and electron beam energy measurements

    Microsoft Academic Search

    E. Baronova; V. Alexandrov

    1996-01-01

    Certain conditions in high temperature plasma (weak electrical field, temperature gradient, parametric instabilities) can lead to the spontaneous magnetic field and suprathermal electron generation. Suprathermal electrons are of great importance in energy transition processes and in plasma emission spectra formation. Soft X-ray line spectroscopy application for magnetic field and electron beam energy measurements in laser produced plasma are presented.

  18. X-Ray Absorption near Edge Structure Spectroscopy of Nanodiamonds from the Allende Meteorite

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.; Keller, L. P.; Hill, H.; Jacobsen, C.; Wirick, S.

    2000-01-01

    Carbon X-ray Absorption Near Edge Structure Spectroscopy shows Allende DM nanodiamonds have two pre-edge peaks, consistent with other small diamonds, but fail to show a diamond exciton which is seen in 3.6 nm diamond thin films.

  19. Studies of supported nickel catalysts by X-ray photoelectron and ion scattering spectroscopies

    Microsoft Academic Search

    Milton. Wu; David M. Hercules

    1979-01-01

    Studies of supported nickel catalysts by X-ray photoelectron and ion scattering spectroscopies provided evidence that nickel does not interact with a silica support but forms nickel monoxide; that on ..gamma..-alumina, low nickel contents form two nickel species which interact with the support, of which one is in tetrahedral alumina sites and difficult to reduce and the other, in octahedral sites

  20. Multi-angular regolith effects on planetary soft X-ray fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Näränen, J.; Parviainen, H.; Carpenter, J.; Muinonen, K.

    2009-04-01

    Fluorescent X-rays from the surfaces of airless planetary bodies in the inner solar system have been measured by instruments on several spacecraft. MESSENGER carries an X-ray spectrometer (XRS) on-board and has already attempted to obtain fluorescent X-rays from the Hermean surface. BepiColombo will later on carry an X-ray telescope (MIXS-T) along with a more conventional collimating detector (MIXS-C) to the Hermean orbit, supported by a next-generation X-ray solar monitor (SIXS). These instruments will provide unprecedented knowledge about the geochemical properties of the Hermean regolith. X-ray emission from planetary surfaces follows photoionisation by incident solar X-rays and charged particles and reveals information about the elemental composition of the surface. Analyses of X-ray spectra, obtained by orbiting spacecraft, use both the relative intensities of elemental emission lines (e.g., Ca/Si, Fe/Si) and absolute abundancies of the elements to determine the geochemistry of the target body. Historically, the analysis of X-ray spectra has largely assumed that surfaces can be considered as homogeneous plane-parallel media. It has been shown, however, that fluorescent line intensities are affected by the physical properties of the target surface (e.g., surface roughness of the regolith) as a function of the viewing and illumination geometry of observations in a way that cannot be explained by the traditional models. We describe experimental investigations where we simulated the effects of regolith properties on the fluorescent lines measured by an orbiting instrument, with a large variety of illumination and viewing angles. The planetary regolith analogue used in these experiments was a terrestrial, olivine rich basalt, which has been used by previous authors as an analogue to the lunar maria. The basalt samples were ground to powder and sieved to discriminate particles in the ranges, <75 micrometers, 75-250 micrometers, and 250-500 micrometers. These separate powders were then pressed into solid pellets. The separation of particles with different sizes allows some determination of the effects due to changes in, e.g., surface roughness. The pellets were imaged with a CT scanner to obtain the physical parameters of the samples. All measurements were made at near-vacuum pressures to prevent absorption of fluorescent X-rays in air. The relative fluorescent line ratios of several major rock-forming elements (e.g., Si, K, Ca, Ti, Fe) were measured. In addition to experimental studies we have simulated the X-ray emission from a regolith using a numerical Monte-Carlo ray-tracing model. This model simulates a regolith of spherical particles, with defined physical properties (particle size distribution, packing density, etc.) and with a realistic macro-scale surface roughness characteristics generated by constraining the surface with a fractional-Brownian-motion surface model. A comparison is made between the modelling and experimental results to validate the modelling. A good agreement between the results is found. We find that both the measured and the simulated spectra become increasingly hard as the phase angle increases (i.e., X-ray lines at higher energies are enhanced relative to those at lower energies). Some hardening of spectra is predicted by the fundamental parameters equation (FPE) of X-ray fluorescence, which assumes a smooth, flat, and homogeneous surface, but we observe further spectral hardening that is in excess to that predicted by the FPE and that this excess hardening is also a function of the surface roughness. We propose to use modelling similar to ours for the data analysis of soft X-ray fluorescence spectra to take the multi-angular effects related to the physical properties of the regolith into account.

  1. Spectroscopically pure metal vapor source for highly charged ion spectroscopy and capillary discharge soft x-ray lasers

    E-print Network

    Rocca, Jorge J.

    of dense plasma columns of interest for both soft x-ray laser research and spectroscopy of highly ionizedSpectroscopically pure metal vapor source for highly charged ion spectroscopy and capillary discharge soft x-ray lasers F. G. Tomasel NSF Center for Extreme Ultraviolet Science and Technology

  2. Variable angle x-ray photoelectron spectroscopy and ion scattering spectroscopy study of the Ag\\/SiOâ interface

    Microsoft Academic Search

    J. R. Pitts; T. M. Thomas; A. W. Czanderna

    1986-01-01

    Thin Ag films of up to one monolayer on high purity fused silica have been investigated using variable angle x-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS). Silvered samples were prepared using the wet chemical process without reducers or by vacuum evaporation. After sensitization with a tin complex, it was determined from ISS that Sn is a surface species

  3. A high-temperature Bonse--Hart ultrasmall-angle x-ray scattering instrument

    SciTech Connect

    Chu, B.; Li, Y.; Harney, P.J.; Yeh, F. (Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400 (United States))

    1993-06-01

    A Bonse--Hart ultrasmall-angle x-ray scattering (USAXS) instrument has been designed, constructed, and tested employing a synchrotron x-ray source. The instrument permits experiments ranging from below 0 [degree]C up to about 400 [degree]C, as well as temperature scanning, jumping, quenching, and annealing experiments. The mechanical elements used Super Invar as the basic building material in order to minimize the thermal expansion effect. As the synchrotron beam after the beamline optics is already somewhat collimated and monochromatized, a very fine tuning of the first crystal was necessary. The high-temperature Bonse--Hart instrument increased the performance by a factor of about 10 when compared with our earlier room-temperature Bonse--Hart instrument using the same set of channel-cut germanium crystals. The instrument was tested by using a suspension of polystyrene latex spheres and by combining the USAXS measurement, for the first time, with measurements of the same latex suspension by means of laser light scattering.

  4. A high-temperature Bonse-Hart ultrasmall-angle x-ray scattering instrument

    NASA Astrophysics Data System (ADS)

    Chu, Benjamin; Li, Yingjie; Harney, Paul J.; Yeh, Fengji

    1993-06-01

    A Bonse-Hart ultrasmall-angle x-ray scattering (USAXS) instrument has been designed, constructed, and tested employing a synchrotron x-ray source. The instrument permits experiments ranging from below 0 °C up to about 400 °C, as well as temperature scanning, jumping, quenching, and annealing experiments. The mechanical elements used Super Invar as the basic building material in order to minimize the thermal expansion effect. As the synchrotron beam after the beamline optics is already somewhat collimated and monochromatized, a very fine tuning of the first crystal was necessary. The high-temperature Bonse-Hart instrument increased the performance by a factor of about 10 when compared with our earlier room-temperature Bonse-Hart instrument using the same set of channel-cut germanium crystals. The instrument was tested by using a suspension of polystyrene latex spheres and by combining the USAXS measurement, for the first time, with measurements of the same latex suspension by means of laser light scattering.

  5. An alpha particle instrument with alpha, proton, and X-ray modes for planetary chemical analyses

    NASA Technical Reports Server (NTRS)

    Economou, T. E.; Turkevich, A. L.

    1976-01-01

    The interaction of alpha particles with matter is employed in a compact instrument that could provide rather complete in-situ chemical analyses of surfaces and thin atmospheres of extraterrestrial bodies. The instrument is a miniaturized and improved version of the Surveyor lunar instrument. The backscattering of alpha particles and (alpha, p) reactions provide analytical data on the light elements (carbon-iron). An X-ray mode that detects the photons produced by the alpha sources provides sensitivity and resolution for the chemical elements heavier than about silicon. The X-rays are detected by semiconductor detectors having a resolution between 150 and 250 eV at 5.9 keV. Such an instrument can identify and determine with good accuracy 99 percent of the atoms (except hydrogen) in rocks. For many trace elements, the detecting sensitivity is a few ppm. Auxiliary sources could be used to enhance the sensitivities for elements of special interest. The instrument could probably withstand the acceleration involved in semi-hard landings.

  6. Application of Si-strip technology to X-ray diffraction instrumentation

    NASA Astrophysics Data System (ADS)

    Gerndt, E.; D?browski, W.; Brügemann, L.; Fink, J.; ?wientek, K.; Wi?cek, P.

    2010-12-01

    We describe the successful technology transfer of High Energy Physics (HEP) silicon-strip detectors for tracking of minimum ionising particles (MIPS) to industrial X-ray diffraction instruments. In our application the detector is used to measure 1-D intensity profiles of low-energy photons. The challenges of such an application are low noise because of the relatively low energy of X-ray photons, from 5 to 22 keV, and high count rate capability. The technical implementation, with a focus on custom designed front-end electronics and optimisation of strip geometry taking into account the charge division effects, is shown and the achieved performance is summarized. The detector was launched several years ago and we report on the in-field experience. Lastly, we describe several scientific applications.

  7. Set of instruments for solar EUV and soft X-ray monitoring onboard satellite Coronas-Photon

    NASA Astrophysics Data System (ADS)

    Kotov, Yury; Kochemasov, Alexey; Kuzin, Sergey; Kuznetsov, Vladimir; Sylwester, Janusz; Yurov, Vitaly

    Coronas-Photon mission is the third satellite of the Russian Coronas program on solar activity observation. The main goal of the "Coronas-Photon" is the study of solar hard electromagnetic radiation in the wide energy range from UV up to high energy gamma-radiation (2000MeV). Scientific payload for solar radiation observation consists of three types of instruments: Monitors (Natalya-2M, Konus-RF, RT-2, Penguin-M, BRM, PHOKA, Sphin-X, SOKOL spectral and timing measurements of full solar disk radiation have timing in flare/burst mode up to one msec. Instruments Natalya-2M, Konus-RF, RT-2 will cover the wide energy range of hard X-rays and soft gamma-rays (15keV to 2000MeV) and will together constitute the largest area detectors ever used for solar observations. Detectors of gamma-ray monitors are based on structured inorganic scintillators. For X-ray and EUV monitors the scintillation phoswich detectors, gas proportional counter, CdZnTe assembly and filter-covered Si-diodes are used. Telescope-spectrometer TESIS for imaging solar spectroscopy in X-rays has angular resolution up to 1arcsec in three spectral lines. Satellite platform and scientific payload is under construction to be launched in autumn 2008. Satellite orbit is circular with initial height 550km and inclination 82.5degrees. Accuracy of the spacecraft orientation to the Sun is better 3arcmin. In the report the capability of PHOKA, SphinX, SOKOL and TESIS as well as the observation program are described and discussed.

  8. Reflection zone plates for 2D focusing and spectroscopy of hard X-rays

    NASA Astrophysics Data System (ADS)

    Löchel, H.; Brzhezinskaya, M.; Firsov, A.; Rehanek, J.; Erko, A.

    2013-03-01

    We propose the use of reflection zone plates (RZP) for two main applications: focusing and spectroscopy. A RZP combines three optical properties - reflection, imaging and dispersion - in one optical element. Having been successfully implemented into an X-ray fs-beamline at BESSY II, RZPs could be an important device in upcoming new high brilliance X-ray sources such as Free Electron Lasers (FEL). The reduction of the number of optical elements in a beamline would allow the highest possible transmission and satisfy the purpose of conserving the unique properties of FELs such as their high coherence.

  9. Two-dimensional stimulated resonance Raman spectroscopy of molecules with broadband x-ray pulses

    PubMed Central

    Biggs, Jason D.; Zhang, Yu; Healion, Daniel; Mukamel, Shaul

    2012-01-01

    Expressions for the two-dimensional stimulated x-ray Raman spectroscopy (2D-SXRS) signal obtained using attosecond x-ray pulses are derived. The 1D- and 2D-SXRS signals are calculated for trans-N-methyl acetamide (NMA) with broad bandwidth (181 as, 14.2 eV FWHM) pulses tuned to the oxygen and nitrogen K-edges. Crosspeaks in 2D signals reveal electronic Franck-Condon overlaps between valence orbitals and relaxed orbitals in the presence of the core-hole. PMID:22583220

  10. A Geiger-mode avalanche photodiode array for X-ray photon correlation spectroscopy.

    PubMed

    Johnson, I; Sadygov, Z; Bunk, O; Menzel, A; Pfeiffer, F; Renker, D

    2009-01-01

    X-ray photon correlation spectroscopy (XPCS) provides an opportunity to study the dynamics of systems by measuring the temporal fluctuations in a far-field diffraction pattern. A two-dimensional detector system has been developed to investigate fluctuations in the frequency range of several Hz to kHz. The X-ray detector system consists of a thin 100 microm scintillation crystal coupled to a Geiger-mode avalanche photodiode array. In this article the elements of the system are detailed and the detector for XPCS measurements is demonstrated. PMID:19096181

  11. X-Ray Absorption Spectroscopy Study of Copper Doped ZnO Thin Films

    SciTech Connect

    Ma Qing [DND-CAT/Northwestern University, Advanced Photon Source, Argonne, IL 60439 (United States); Buchholz, D. B.; Anderson, Mark; Aagesen, Larry; Chang, R. P. H. [Materials Science and Engineering, Northwestern University, Evanston, IL 60208 (United States)

    2007-02-02

    X-ray absorption spectroscopy technique is used to study copper-doped ZnO thin films, prepared by pulsed-laser deposition. The samples with various doping levels are examined. It is found that the samples contain metallic clusters with the sizes {<=} 2 nm as well as Cu1+ and Cu2+ states. The Cu1+ states exist as stable oxide clusters, while the Cu2+ ones participate in the ZnO lattice some of which may be pertaining to the surfaces of the Cu clusters as well. The copper clusters of {approx}1 nm are unstable and fragment under monochromatic x-ray beam illumination.

  12. Two-dimensional stimulated resonance Raman spectroscopy of molecules with broadband x-ray pulses

    NASA Astrophysics Data System (ADS)

    Biggs, Jason D.; Zhang, Yu; Healion, Daniel; Mukamel, Shaul

    2012-05-01

    Expressions for the two-dimensional stimulated x-ray Raman spectroscopy (2D-SXRS) signal obtained using attosecond x-ray pulses are derived. The 1D- and 2D-SXRS signals are calculated for trans-N-methyl acetamide (NMA) with broad bandwidth (181 as, 14.2 eV FWHM) pulses tuned to the oxygen and nitrogen K-edges. Crosspeaks in 2D signals reveal electronic Franck-Condon overlaps between valence orbitals and relaxed orbitals in the presence of the core-hole.

  13. Thermal Expansion Behaviour of Silver Examined by Extended X-Ray Absorption Fine Structure Spectroscopy

    SciTech Connect

    Dubiel, M.; Chasse, A.; Haug, J.; Schneider, R.; Kruth, H. [Department of Physics, Martin Luther University of Halle-Wittenberg, Friedemann-Bach-Platz 6, D-06108 Halle (Germany)

    2007-02-02

    EXAFS (extended X-ray absorption fine structure) investigations are reported concerning the thermal expansion behaviour of silver in an extended range of temperature from 10 K to about 950 K measured in transmission mode. Both the ratio method and an EXAFS fitting procedure were applied to reveal the temperature dependence of EXAFS parameters. Models based on quantum and classical thermodynamic perturbation theory have been used to interpret experimental data and compared to XRD (X-ray diffraction) results of bulk silver material. The description of thermodynamic data of thermal expansion of silver in the complete range of temperature by EXAFS Spectroscopy was successful by first calculations using third order quantum perturbation theory.

  14. Anodic behaviour and X-ray photoelectron spectroscopy of ternary tin oxides

    Microsoft Academic Search

    N. Sharma; K. M. Shaju; G. V. Subba Rao; B. V. R. Chowdari

    2005-01-01

    The compounds SrSnO3, BaSnO3 and Ca2SnO4 have been synthesized by solid-state and\\/or sol–gel methods, characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) and their electrochemical properties studied as cathodes versus Li metal in the range 0.005–1.0V. ASnO3 (A = Sr, Ba), adopt the perovskite structure whereas Ca2SnO4 has the Sr2PbO4 structure. The discharge capacities

  15. A New Route to Phase-Resolved Spectroscopy of QPOs in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Stevens, A.; Uttley, P.; van der Klis, M.

    2015-07-01

    I will present the application of a new spectral-timing technique for phase-resolved X-ray spectroscopy of low-frequency quasi-periodic oscillations (QPOs) from black hole X-ray binaries. These signals are thought to originate from near-periodic geometric changes in the inner accretion flow, possibly due to general relativistic Lense-Thirring precession. Our technique lets us study how the different spectral components change with QPO phase, providing a crucial test of the model and providing new insight into the geometry of the emitting region and accretion flow in the strong-field gravity regime close to black holes.

  16. High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies

    PubMed Central

    Strocov, V. N.; Schmitt, T.; Flechsig, U.; Schmidt, T.; Imhof, A.; Chen, Q.; Raabe, J.; Betemps, R.; Zimoch, D.; Krempasky, J.; Wang, X.; Grioni, M.; Piazzalunga, A.; Patthey, L.

    2010-01-01

    The concepts and technical realisation of the high-resolution soft X-ray beamline ADRESS operating in the energy range from 300 to 1600?eV and intended for resonant inelastic X-ray scattering (RIXS) and angle-resolved photoelectron spectroscopy (ARPES) are described. The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0–180° rotatable linear polarizations) but also the energy without changing the gap. The beamline optics is based on the well established scheme of plane-grating monochromator operating in collimated light. The ultimate resolving power E/?E is above 33000 at 1?keV photon energy. The choice of blazed versus lamellar gratings and optimization of their profile parameters is described. Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 × 1013?photons s?1 (0.01% BW)?1 at 1?keV. Ellipsoidal refocusing optics used for the RIXS endstation demagnifies the vertical spot size down to 4?µm, which allows slitless operation and thus maximal transmission of the high-resolution RIXS spectrometer delivering E/?E > 11000 at 1?keV photon energy. Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed. An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given. PMID:20724785

  17. Constellation-X Spectroscopy X-ray Telescope requirements and development program: MSFC research program

    Microsoft Academic Search

    Stephen L. O'Dell; William D. Jones; J. K. Russell; Brian D. Ramsey; Darell E. Engelhaupt; Lester M. Cohen; Leon P. Van Speybroeck

    1999-01-01

    The Constellation-X Spectroscopy X-ray Telescope (SXT) will provide high-throughput, high-resolution spectroscopy of cosmic sources, form 0.25 keV to 10 keV. Key to this capability is the development of large, lightweight optics for the SXT mirror assembly. Teams led by NASA's Marshall Space Flight Center (MSFC), by NASA's Goddard Space Flight Center (GSFC), and by Italy's Osservatorio Astronomico di Brera are

  18. Surface chemistry of HF passivated silicon: X-ray photoelectron and ion scattering spectroscopy results

    Microsoft Academic Search

    B. R. Weinberger; G. G. Peterson; T. C. Eschrich; H. A. Krasinski

    1986-01-01

    X-ray photoelectron spectroscopy and ion scattering spectroscopy studies of HF-treated silicon surfaces are described in an effort to understand the chemical termination leading to the near ideal electrical passivation of such surfaces. Results suggest a fluorine surface density of order a monolayer chemically bonded to silicon with a partial oxygen contamination due to exposure of the HF-treated wafer to air,

  19. X-ray spectroscopy of plasmas created by the Nike KrF laser

    SciTech Connect

    Aglitskiy, Y.; Lehecka, T.; Deniz, A.; Hardgrove, J. [Science Applications International Corporation, McLean, Virginia 22102 (United States)] [Science Applications International Corporation, McLean, Virginia 22102 (United States); Seely, J.; Brown, C.; Feldman, U. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)] [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Pawley, C.; Gerber, K.; Bodner, S.; Obenschain, S.; Lehmberg, R.; McLean, E.; Pronko, M.; Sethian, J.; Stamper, J.; Schmitt, A.; Sullivan, C. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)] [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Holland, G.; Laming, M. [SFA Inc., 1401 McCormick Drive, Landover, Maryland 20785 (United States)] [SFA Inc., 1401 McCormick Drive, Landover, Maryland 20785 (United States)

    1997-01-01

    The x-ray emission from plasmas created by the Naval Research Laboratory Nike KrF laser was characterized using spectroscopic instruments. The targets were thin foils of aluminum and titanium and were irradiated by laser energies in the range 100{endash}1500 J. Using a spherical-crystal imaging spectrometer operating in the 1{endash}2 keV x-ray region, the density, temperature, and opacity of aluminum plasmas were determined with a spatial resolution of 10 {mu}m in the direction perpendicular to the target surface. The spectral line ratios indicated that the aluminum plasmas were relatively dense, cool, and optically thick near the target surface.

  20. X-RAY ABSORPTION SPECTROSCOPY OF YB3+-DOPED OPTICAL FIBERS

    SciTech Connect

    Citron, Robert; Kropf, A.J.

    2008-01-01

    Optical fibers doped with Ytterbium-3+ have become increasingly common in fiber lasers and amplifiers. Yb-doped fibers provide the capability to produce high power and short pulses at specific wavelengths, resulting in highly effective gain media. However, little is known about the local structure, distribution, and chemical coordination of Yb3+ in the fibers. This information is necessary to improve the manufacturing process and optical qualities of the fibers. Five fibers doped with Yb3+ were studied using Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy and X-ray Absorption Near Edge Spectroscopy (XANES), in addition to Yb3+ mapping. The Yb3+ distribution in each fiber core was mapped with 2D and 1D intensity scans, which measured X-ray fluorescence over the scan areas. Two of the five fibers examined showed highly irregular Yb3+ distributions in the core center. In four of the five fibers Yb3+ was detected outside of the given fiber core dimensions, suggesting possible Yb3+ diffusion from the core, manufacturing error, or both. X-ray absorption spectroscopy (XAS) analysis has so far proven inconclusive, but did show that the fibers had differing EXAFS spectra. The Yb3+ distribution mapping proved highly useful, but additional modeling and examination of fiber preforms must be conducted to improve XAS analysis, which has been shown to have great potential for the study of similar optical fi bers.

  1. X-Ray Diffraction and Fluorescence Measurements for In Situ Planetary Instruments

    NASA Astrophysics Data System (ADS)

    Hansford, G.; Hill, K. S.; Talboys, D.; Vernon, D.; Ambrosi, R.; Bridges, J.; Hutchinson, I.; Marinangeli, L.

    2011-12-01

    The ESA/NASA ExoMars mission, due for launch in 2018, has a combined X-ray fluorescence/diffraction instrument, Mars-XRD, as part of the onboard analytical laboratory. The results of some XRF (X-ray fluorescence) and XRD (X-ray diffraction) tests using a laboratory chamber with representative performance are reported. A range of standard geological reference materials and analogues were used in these tests. The XRD instruments are core components of the forthcoming NASA Mars Science Laboratory (MSL) and ESA/NASA ExoMars missions and will provide the first demonstrations of the capabilities of combined XRD/XRF instrumentation in situ on an extraterrestrial planetary surface. The University of Leicester team is part of the Italy-UK collaboration that is responsible for building the ExoMars X-ray diffraction instrument, Mars-XRD [1,2]. Mars-XRD incorporates an Fe-55 radioisotope source and three fixed-position charge-coupled devices (CCDs) to simultaneously acquire an X-ray fluorescence spectrum and a diffraction pattern providing a measurement of both elemental and mineralogical composition. The CCDs cover an angular range of 2? = 6° to 73° enabling the analysis of a wide range of geologically important minerals including phyllosilicates, feldspars, oxides, carbonates and evaporites. The identification of hydrous minerals may help identify past Martian hydrothermal systems capable of preserving traces of life. Here we present some initial findings from XRF and XRD tests carried out at the University of Leicester using an Fe-55 source and X-ray sensitive CCD. The XRF/XRD test system consists of a single CCD on a motorised arm, an Fe-55 X-ray source, a collimator and a sample table which approximately replicate the reflection geometry of the Mars-XRD instrument. It was used to test geological reference standard materials and Martian analogues. This work was funded by the Science and Technology Facilities Council, UK. References [1] Marinangeli, L., Hutchinson, I., Baliva, A., Stevoli, A., Ambrosi, R., Critani, F., Delhez, R., Scandelli, L., Holland, A., Nelms, N. & the Mars-XRD Team, Proceedings of the 38th Lunar and Planetary Science Conference, 12 - 16 March 2007, League City, Texas, USA. [2] L. Marinangeli, I. B. Hutchinson, A. Stevoli, G. Adami, R. Ambrosi, R. Amils, V. Assis Fernandes, A. Baliva, A. T. Basilevsky, G. Benedix, P. Bland, A. J. Böttger, J. Bridges, G. Caprarelli, G. Cressey, F. Critani, N. d'Alessandro, R. Delhez, C. Domeneghetti, D. Fernandez-Remolar, R. Filippone, A. M. Fioretti, J. M. Garcia Ruiz, M. Gilmore, G. M. Hansford, G. Iezzi, R. Ingley, M. Ivanov, G. Marseguerra, L. Moroz, C. Pelliciari, P. Petrinca, E. Piluso, L. Pompilio, J. Sykes, F. Westall and the MARS-XRD Team, EPSC-DPS Joint Meeting 2011, 3 - 7 October 2011, La Cité Internationale des Congrès Nantes Métropole, Nantes, France.

  2. Energy-dispersive X-ray emission spectroscopy using an X-ray free-electron laser in a shot-by-shot mode.

    PubMed

    Alonso-Mori, Roberto; Kern, Jan; Gildea, Richard J; Sokaras, Dimosthenis; Weng, Tsu-Chien; Lassalle-Kaiser, Benedikt; Tran, Rosalie; Hattne, Johan; Laksmono, Hartawan; Hellmich, Julia; Glöckner, Carina; Echols, Nathaniel; Sierra, Raymond G; Schafer, Donald W; Sellberg, Jonas; Kenney, Christopher; Herbst, Ryan; Pines, Jack; Hart, Philip; Herrmann, Sven; Grosse-Kunstleve, Ralf W; Latimer, Matthew J; Fry, Alan R; Messerschmidt, Marc M; Miahnahri, Alan; Seibert, M Marvin; Zwart, Petrus H; White, William E; Adams, Paul D; Bogan, Michael J; Boutet, Sébastien; Williams, Garth J; Zouni, Athina; Messinger, Johannes; Glatzel, Pieter; Sauter, Nicholas K; Yachandra, Vittal K; Yano, Junko; Bergmann, Uwe

    2012-11-20

    The ultrabright femtosecond X-ray pulses provided by X-ray free-electron lasers open capabilities for studying the structure and dynamics of a wide variety of systems beyond what is possible with synchrotron sources. Recently, this "probe-before-destroy" approach has been demonstrated for atomic structure determination by serial X-ray diffraction of microcrystals. There has been the question whether a similar approach can be extended to probe the local electronic structure by X-ray spectroscopy. To address this, we have carried out femtosecond X-ray emission spectroscopy (XES) at the Linac Coherent Light Source using redox-active Mn complexes. XES probes the charge and spin states as well as the ligand environment, critical for understanding the functional role of redox-active metal sites. K?(1,3) XES spectra of Mn(II) and Mn(2)(III,IV) complexes at room temperature were collected using a wavelength dispersive spectrometer and femtosecond X-ray pulses with an individual dose of up to >100 MGy. The spectra were found in agreement with undamaged spectra collected at low dose using synchrotron radiation. Our results demonstrate that the intact electronic structure of redox active transition metal compounds in different oxidation states can be characterized with this shot-by-shot method. This opens the door for studying the chemical dynamics of metal catalytic sites by following reactions under functional conditions. The technique can be combined with X-ray diffraction to simultaneously obtain the geometric structure of the overall protein and the local chemistry of active metal sites and is expected to prove valuable for understanding the mechanism of important metalloproteins, such as photosystem II. PMID:23129631

  3. Energy-dispersive X-ray emission spectroscopy using an X-ray free-electron laser in a shot-by-shot mode

    PubMed Central

    Alonso-Mori, Roberto; Kern, Jan; Gildea, Richard J.; Sokaras, Dimosthenis; Weng, Tsu-Chien; Lassalle-Kaiser, Benedikt; Tran, Rosalie; Hattne, Johan; Laksmono, Hartawan; Hellmich, Julia; Glöckner, Carina; Echols, Nathaniel; Sierra, Raymond G.; Schafer, Donald W.; Sellberg, Jonas; Kenney, Christopher; Herbst, Ryan; Pines, Jack; Hart, Philip; Herrmann, Sven; Grosse-Kunstleve, Ralf W.; Latimer, Matthew J.; Fry, Alan R.; Messerschmidt, Marc M.; Miahnahri, Alan; Seibert, M. Marvin; Zwart, Petrus H.; White, William E.; Adams, Paul D.; Bogan, Michael J.; Boutet, Sébastien; Williams, Garth J.; Zouni, Athina; Messinger, Johannes; Glatzel, Pieter; Sauter, Nicholas K.; Yachandra, Vittal K.; Yano, Junko; Bergmann, Uwe

    2012-01-01

    The ultrabright femtosecond X-ray pulses provided by X-ray free-electron lasers open capabilities for studying the structure and dynamics of a wide variety of systems beyond what is possible with synchrotron sources. Recently, this “probe-before-destroy” approach has been demonstrated for atomic structure determination by serial X-ray diffraction of microcrystals. There has been the question whether a similar approach can be extended to probe the local electronic structure by X-ray spectroscopy. To address this, we have carried out femtosecond X-ray emission spectroscopy (XES) at the Linac Coherent Light Source using redox-active Mn complexes. XES probes the charge and spin states as well as the ligand environment, critical for understanding the functional role of redox-active metal sites. K?1,3 XES spectra of MnII and Mn2III,IV complexes at room temperature were collected using a wavelength dispersive spectrometer and femtosecond X-ray pulses with an individual dose of up to >100 MGy. The spectra were found in agreement with undamaged spectra collected at low dose using synchrotron radiation. Our results demonstrate that the intact electronic structure of redox active transition metal compounds in different oxidation states can be characterized with this shot-by-shot method. This opens the door for studying the chemical dynamics of metal catalytic sites by following reactions under functional conditions. The technique can be combined with X-ray diffraction to simultaneously obtain the geometric structure of the overall protein and the local chemistry of active metal sites and is expected to prove valuable for understanding the mechanism of important metalloproteins, such as photosystem II. PMID:23129631

  4. Simultaneous Femtosecond X-ray Spectroscopy and Diffraction of Photosystem II at Room Temperature

    PubMed Central

    Kern, Jan; Alonso-Mori, Roberto; Tran, Rosalie; Hattne, Johan; Gildea, Richard J.; Echols, Nathaniel; Glöckner, Carina; Hellmich, Julia; Laksmono, Hartawan; Sierra, Raymond G.; Lassalle-Kaiser, Benedikt; Koroidov, Sergey; Lampe, Alyssa; Han, Guangye; Gul, Sheraz; DiFiore, Dörte; Milathianaki, Despina; Fry, Alan R.; Miahnahri, Alan; Schafer, Donald W.; Messerschmidt, Marc; Seibert, M. Marvin; Koglin, Jason E.; Sokaras, Dimosthenis; Weng, Tsu-Chien; Sellberg, Jonas; Latimer, Matthew J.; Grosse-Kunstleve, Ralf W.; Zwart, Petrus H.; White, William E.; Glatzel, Pieter; Adams, Paul D.; Bogan, Michael J.; Williams, Garth J.; Boutet, Sébastien; Messinger, Johannes; Zouni, Athina; Sauter, Nicholas K.; Yachandra, Vittal K.; Bergmann, Uwe; Yano, Junko

    2013-01-01

    Intense femtosecond X-ray pulses produced at the Linac Coherent Light Source (LCLS) were used for simultaneous X-ray diffraction (XRD) and X-ray emission spectroscopy (XES) of microcrystals of Photosystem II (PS II) at room temperature. This method probes the overall protein structure and the electronic structure of the Mn4CaO5 cluster in the oxygen-evolving complex of PS II. XRD data are presented from both the dark state (S1) and the first illuminated state (S2) of PS II. Our simultaneous XRD/XES study shows that the PS II crystals are intact during our measurements at the LCLS, not only with respect to the structure of PS II, but also with regard to the electronic structure of the highly radiation sensitive Mn4CaO5 cluster, opening new directions for future dynamics studies. PMID:23413188

  5. Characterization of surface carbon films on weathered Japaneseroof tiles by soft x-ray spectroscopy

    SciTech Connect

    Muramatsu, Y.; Yamashita, M.; Motoyama, M.; Hirose, M.; Denlinger, J.D.; Gullikson, E.M.; Perera, R.C.

    2004-07-15

    The effects of weathering on carbon films deposited onJapanese smoked roof tileswere investigated by soft x-ray absorption andemission spectroscopy using synchrotron radiation. X-ray absorptionmeasurements revealed that weathering oxidizes the carbon films and thatpartial carboxy chemical bonding occurs. Incident angle-dependent x-rayabsorption spectra in the C K region confirmed that the degree of theorientation at the surface of the oxidized carbon films decreases withweathering. However, the take-off angle-dependent C K x-ray emissionspectra showed that the orientation of the layered carbon structure ismaintained in the bulk portion when weathered. Therefore, it is confirmedthat oxidation proceeds from the surface of the carbon films. Weatheringdegrades and oxidizes the surface carbon films, which causes the metallicsilver color to change to darker gray.

  6. Polarization spectroscopy of x-ray transitions from beam-excited highly charged ions

    SciTech Connect

    Beiersdorfer, P.; Lopez-Urrutia, J.C.; Decaux, V.; Widmann, K. [Department of Physics and Space Technology, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Department of Physics and Space Technology, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Neill, P. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)] [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)

    1997-01-01

    Polarization spectroscopy of x-ray lines represents a diagnostic tool to ascertain the presence of electron beams in high-temperature plasmas. Making use of the Livermore electron beam ion trap, which optimizes the linear x-ray line polarization by exciting highly charged ions with a monoenergetic electron beam, we have begun to develop polarization diagnostics and test theoretical models. Our measurement relies on the sensitivity of crystal spectrometers to the linear polarization of x-ray lines which depends on the value of the Bragg angle. We employed two spectrometers with differing analyzing crystals and simultaneously recorded the K-shell emission from heliumlike Fe{sup 24+} and lithiumlike Fe{sup 23+} ions at two different Bragg angles. A clear difference in the relative intensities of the dominant transitions is observed, which is attributed to the amount of linear polarization of the individual lines. {copyright} {ital 1997 American Institute of Physics.}

  7. Gas cell for in situ soft X-ray transmission-absorption spectroscopy of materials

    SciTech Connect

    Drisdell, W. S.; Kortright, J. B. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-07-15

    A simple gas cell design, constructed primarily from commercially available components, enables in situ soft X-ray transmission-absorption spectroscopy of materials in contact with gas at ambient temperature. The cell has a minimum X-ray path length of 1 mm and can hold gas pressures up to ?300 Torr, and could support higher pressures with simple modifications. The design enables cycling between vacuum and gas environments without interrupting the X-ray beam, and can be fully sealed to allow for measurements of air-sensitive samples. The cell can attach to the downstream port of any appropriate synchrotron beamline, and offers a robust and versatile method for in situ measurements of certain materials. The construction and operation of the cell are discussed, as well as sample preparation and proper spectral analysis, illustrated by examples of spectral measurements. Potential areas for improvement and modification for specialized applications are also mentioned.

  8. X-ray spectroscopy of Cu impurities on NSTX and comparison with Z-pinch plasmas.

    PubMed

    Safronova, A S; Ouart, N D; Lepson, J K; Beiersdorfer, P; Stratton, B; Bitter, M; Kantsyrev, V L; Cox, P G; Shlyaptseva, V; Williamson, K M

    2010-10-01

    X-ray spectroscopy of mid-Z metal impurities is important in the study of tokamak plasmas and may reveal potential problems if their contribution to the radiated power becomes substantial. The analysis of the data from a high-resolution x-ray and extreme ultraviolet grating spectrometer, XEUS, installed on NSTX, was performed focused on a detailed study of x-ray spectra in the range 7-18 A?. These spectra include not only commonly seen iron spectra but also copper spectra not yet employed as an NSTX plasma impurity diagnostic. In particular, the L-shell Cu spectra were modeled and predictions were made for identifying contributions from various Cu ions in different spectral bands. Also, similar spectra, but from much denser Cu plasmas produced on the UNR Z-pinch facility and collected using the convex-crystal spectrometer, were analyzed and compared with NSTX results. PMID:21034004

  9. Bayesian Comparison of Fit Parameters: An Application to Time-Resolved X-Ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kashyap, V.

    Analysis of X-ray data of the stars AD Leo and Wolf 630, obtained with ROSAT provide important clues to the structure of the coronae on these low-mass, main-sequence stars. In particular, time-resolved X-ray spectroscopy of these stars allow us to derive estimates for the low- and high-temperature components of the plasma emission measures. Using Bayes' theorem, we show that the high-temperature components are correlated with the X-ray light-curves of the stars, while the low-temperature components are steady. Thus we are able to model the low-temperature emission as relatively compact, quiescent, static coronal loops, and the high-temperature emission as unstable flaring components.

  10. Optical Spectroscopy of Candidate X-ray Binaries in the Starburst IC 10

    NASA Astrophysics Data System (ADS)

    Balchunas, Andrew J.; Laycock, S.; Camero, A.; Wilson-Hodge, C.; Williams, B.; Garcia, M.; Prestwich, A.; Galache, J.; Capallo, R.

    2011-09-01

    The dwarf irregular galaxy IC10 in Cassiopeia, is the youngest available starburst galaxy and home to many X-ray sources. Using the Gemini multi-object spectrograph (GMOS), in the wavelength range containing H-alpha, we obtained spectra of twenty five stars that are positionally coincident with X-ray sources, at the 95% significance level. The spectral class of each star is compared against its optical magnitude, and de-reddened intrinsic color. The spectroscopy allows us to determine which of the sources are definitely in IC10, based on their redshift, which are Galactic, and which are probably background quasars. Several of the sources are X-ray variables, as discovered in our 2003-2010 Chandra monitoring sequence and their properties will be studied in more detail.

  11. Quantifying defect levels in hexagonal boron nitride from simulated x-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Huber, Sebastiaan; van de Kruijs, Robbert; Bijkerk, Fred; Gullikson, Eric; Prendergast, David

    2015-03-01

    X-ray Absorption Spectroscopy is a technique that is highly sensitive to the local structural and chemical environment of the probed species. This quality can be exploited to investigate the characteristics of localized structural imperfections such as point defects and grain boundaries. In this study the X-ray absorption spectra for various hexagonal (h-BN) and amorphous boron nitride (a-BN) samples have been recorded. Simulation of X-ray absorption spectra from first principles allows for characteristic features in the measured spectra to be attributed to local defects of the planar hexagonal structure of the material. Analysis of the relative intensities of these features can subsequently provide a quantitative analysis of the levels of various defects in the analyzed structure. This work is supported by NanoNextNL, a micro and nanotechnology programme of the Dutch Government and 130 partners.

  12. IN SITU STUDIES OF CORROSION USING X-RAY ABSORPTION NEAR SPECTROSCOPY (XANES)

    SciTech Connect

    ISAACS, H.S.; SCHMUKI, P.; VIRTANEN, S.

    2001-03-25

    Applications of x-ray absorption near-edge spectroscopy (XANES) and the design of cells for in situ corrosion studies are reviewed. Passive films studies require very thin metal or alloy layers be used having a thickness of the order of the films formed because of penetration of the x-ray beam into the metal substrate. The depth of penetration in water also limits the thickness of solutions that can be used because of water reduces the x-ray intensity. Solution thickness must also be limited in studies of conversion layer formation studies because the masking of the Cr in solution. Illustrative examples are taken from the anodic behavior of Al-Cr alloys, the growth of passive films on Fe and stainless steels, and the formation of chromate conversion layers on Al.

  13. Photodissociation structural dynamics of trirutheniumdodecacarbonyl investigated by X-ray transient absorption spectroscopy.

    PubMed

    Harpham, Michael R; Stickrath, Andrew B; Zhang, Xiaoyi; Huang, Jier; Mara, Michael W; Chen, Lin X; Liu, Di-Jia

    2013-10-01

    The molecular and electronic structures of the transient intermediates generated from the photolysis of trirutheniumdodecacarbonyl, Ru3(CO)12, by ultrafast UV (351 nm) laser excitation were investigated using X-ray transient absorption (XTA) spectroscopy. The electronic configuration change and nuclear rearrangement after the dissociation of carbonyls were observed at ruthenium K-edge X-ray absorption near edge structure and X-ray absorption fine structure spectra. Analysis of XTA data, acquired after 100, 200, and 400 ps and 300 ns time delay following the photoexcitation, identified the presence of three intermediate species with Ru3(CO)10 being the most dominating one. The results set an example of applying XTA in capturing both transient electronic and nuclear configurations in metal clusters simulating catalysts in chemical reactions. PMID:23697577

  14. Picosecond-resolved X-ray absorption spectroscopy at low signal contrast using a hard X-ray streak camera.

    PubMed

    Adams, Bernhard W; Rose-Petruck, Christoph; Jiao, Yishuo

    2015-07-01

    A picosecond-resolving hard-X-ray streak camera has been in operation for several years at Sector 7 of the Advanced Photon Source (APS). Several upgrades have been implemented over the past few years to optimize integration into the beamline, reduce the timing jitter, and improve the signal-to-noise ratio. These include the development of X-ray optics for focusing the X-rays into the sample and the entrance slit of the streak camera, and measures to minimize the amount of laser light needed to generate the deflection-voltage ramp. For the latter, the photoconductive switch generating the deflection ramp was replaced with microwave power electronics. With these, the streak camera operates routinely at 88?MHz repetition rate, thus making it compatible with all of the APS fill patterns including use of all the X-rays in the 324-bunch mode. Sample data are shown to demonstrate the performance. PMID:26134806

  15. Novel technique for high-precision Bragg-angle determination in crystal x-ray spectroscopy

    SciTech Connect

    Braun, J.; Bruhns, H.; Trinczek, M.; Lopez-Urrutia, J. R. Crespo; Ullrich, J. [Max-Planck-Institute for Nuclear Physics, D-69117 Heidelberg (Germany)

    2005-07-15

    A novel technique for a high-precision large acceptance determination of the Bragg angle in crystal x-ray spectroscopy is presented and demonstrated. The method exploits visible light beams as fiducials reflected on the x-ray crystal's surface to ensure exact knowledge of the position on the crystal at which the x rays are reflected, replacing entrance slits, thus making flat crystals suitable for low x-ray fluxes. It can be shown that many error sources arising from uncertainties in the determination of geometrical properties are eliminated in this way. A flat crystal x-ray spectrometer based on this technique has been designed, built, and tested using the most precisely known wavelengths emitted by highly charged ions, namely H- and He-like argon. The result for the 1s2p {sup 1}P{sub 1}{yields}1s{sup 2} {sup 1}S{sub 0} w-line of He-like argon exhibits a statistical uncertainty of 3.8 ppm and an estimated systematic error of about 3 ppm, thus becoming the most accurate measurement of the He-like resonance transition in highly charged ions. It is shown that achieving a systematic error of below 1 ppm is feasible with this method. Therefore, our technique should allow reaching total accuracies approaching 1 ppm on transitions of mid-Z highly charged ions, which would provide challenging tests for state-of-the-art theoretical predictions.

  16. Soft x-ray spectroscopy studies of novel electronic materials using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Newby, David, Jr.

    Soft x-ray spectroscopy can provide a wealth of information on the electronic structure of solids. In this work, a suite of soft x-ray spectroscopies is applied to organic and inorganic materials with potential applications in electronic and energy generation devices. Using the techniques of x-ray absorption (XAS), x-ray emission spectroscopy (XES), and x-ray photoemission spectroscopy (XPS), the fundamental properties of these different materials are explored. Cycloparaphenylenes (CPPs) are a recently synthesized family of cyclic hydrocarbons with very interesting properties and many potential applications. Unusual UV/Visible fluorescence trends have spurred a number of theoretical investigations into the electronic properties of the CPP family, but thus far no comprehensive electronic structure measurements have been conducted. XPS, XAS, and XES data for two varieties, [8]- and [10]-CPP, are presented here, and compared with the results of relevant DFT calculations. Turning towards more application-centered investigations, similar measurements are applied to two materials commonly used in solid oxide fuel cell (SOFC) cathodes: La1-xSrxMnO 3 (LSMO) and La1-xSr1- xCo1-yFe yO3 (LSCF). Both materials are structurally perovskites, but they exhibit strikingly different electronic properties. SOFC systems very efficiently produce electricity by catalyzing reactions between oxygen and petroleum-based hydrocarbons at high temperatures (> 800 C). Such systems are already utilized to great effect in many industries, but more widespread adoption could be had if the cells could operate at lower temperatures. Understanding the electronic structure and operational evolution of the cathode materials is essential for the development of better low-temperature fuel cells. LSCF is a mixed ion-electron conductor which holds promise for low-temperature SOFC applications. XPS spectra of LSCF thin films are collected as the films are heated and gas-dosed in a controlled environment. The surface evolution of these films is discussed, and the effects of different gas environments on oxygen vacancy concentration are elucidated. LSMO is commonly used in commercial fuel cell devices. Here the resonant soft x-ray emission (RIXS) spectrum of LSMO is examined, and it is shown that the inelastic x-ray emission structure of LSMO arises from local atomic multiplet effects.

  17. Electronic and geometric structure of chromium clusters deposited onto Ru(001) studied by soft X-ray absorption spectroscopy

    Microsoft Academic Search

    J. T. Lau; A. Achleitner; W. Wurth

    2000-01-01

    Small, size-selected Crn clusters deposited onto Ru(001) have been studied by soft X-ray absorption spectroscopy. Broad, bulk-like L3 absorption line shapes are observed for all clusters. Sizeable shifts in X-ray absorption energy after flash heating are indicative of diffusion or surface alloying. Pure Crn clusters can be easily oxidised, yielding Cr2O3-like X-ray absorption signals. The results are discussed in comparison

  18. X-ray Correlation Spectroscopy Investigations of the Charge-density Wave Depinning Transition in pure NbSe3

    Microsoft Academic Search

    R. L. Sampson; J.-D. Su; J. D. Brock; R. E. Thorne; Mark Sutton

    2004-01-01

    We report synchrotron based x-ray scattering and electronic transport measurements of the charge density wave (CDW) depinning transition in pure NbSe_3. Coherent x-rays provided at the 8-ID beam-line at the Advanced Photon Source enabled the implementation of the X-ray Photon Correlation Spectroscopy technique to wide angles in order to investigate the dynamics of both the pinned and sliding CDW states.

  19. Molecular environment of iodine in naturally iodinated humic substances: Insight from X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Schlegel, Michel L.; Reiller, Pascal; Mercier-Bion, Florence; Barré, Nicole; Moulin, Valérie

    2006-11-01

    The molecular environment of iodine in reference inorganic and organic compounds, and in dry humic and fulvic acids (HAs and FAs) extracted from subsurface and deep aquifers was probed by iodine L 3-edge X-ray absorption spectroscopy. The X-ray absorption near-edge structure (XANES) of iodine spectra from HAs and FAs resembled those of organic references and displayed structural features consistent with iodine forming covalent bonds with organic molecules. Simulation of XANES spectra by linear combination of reference spectra suggested the predominance of iodine forming covalent bonds to aromatic rings (aromatic-bound iodine). Comparison of extended X-ray absorption fine structure (EXAFS) spectra of reference and samples further showed that iodine was surrounded by carbon shells at distances comparables to those for references containing aromatic-bound iodine. Quantitative analysis of EXAFS spectra indicated that iodine was bound to about one carbon at a distance d (I-C) of 2.01(4)-2.04(9) Å, which was comparable to the distances observed for aromatic-bound iodine in references (1.99(1)-2.07(6) Å), and significantly shorter than that observed for aliphatic-bound iodine (2.15(2)-2.16(2) Å). These results are in agreement with previous conclusions from X-ray photoelectron spectroscopy and from electrospray ionization mass spectrometry. These results collectively suggest that the aromatic-bound iodine is stable in the various aquifers of this study.

  20. Instrument for nm-scale spatial resolution x-ray microscopy using MLL optics

    NASA Astrophysics Data System (ADS)

    Nazaretski, Evgeny; Yan, Hanfei; Lauer, Kenneth; Mullany, Brian; Kuhne, Dennis; Xu, Weihe; Huang, Xiaojing; Gofron, Kazimierz; Kalbfleisch, Sebastian; Yan, Hui; Shu, Deming; Bouet, Nathalie; Zhou, Juan; Conley, Raymond; Chu, Yong

    2015-03-01

    The Hard X-ray Nanoprobe (HXN) beamline at the NSLS-II has been designed and constructed to address challenges related to nanoscale science and technology. HXN will provide a suite of experimental capabilities which include scanning fluorescence, diffraction, differential phase contrast and ptychography utilizing Multilayer Laue Lenses (MLL) and zoneplate (ZP) as nanofocusing optics. To provide more versatility and explore the phase space in materials research studies, the instrument is equipped with a temperature regulation system capable of varying specimen temperature between 100 K and 1000 K. During this presentation, different phases of the instrument development process will be reviewed. Various prototype systems designed and constructed will be discussed. Preliminary data demonstrating 2D sub-20 nm imaging resolution using MLL optics will be presented. Some of the early science applications will be covered emphasizing strengths of the developed instrument.

  1. Electronic structure of the organic semiconductor Alq3 (aluminum tris-8-hydroxyquinoline) from soft x-ray spectroscopies and density functional theory calculations

    Microsoft Academic Search

    A. Demasi; L. F. J. Piper; Y. Zhang; I. Reid; S. Wang; K. E. Smith; J. E. Downes; N. Peltekis; C. McGuinness; A. Matsuura

    2008-01-01

    The element-specific electronic structure of the organic semiconductor aluminum tris-8-hydroxyquinoline (Alq3) has been studied using a combination of resonant x-ray emission spectroscopy, x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, and density functional theory (DFT) calculations. Resonant and nonresonant x-ray emission spectroscopy were used to measure directly the carbon, nitrogen and oxygen 2p partial densities of states in Alq3, and good agreement

  2. Redox Chemisty of Tantalum Clusters on Silica Characterized by X-ray Absorption Spectroscopy

    SciTech Connect

    Nemana,S.; Gates, B.

    2006-01-01

    SiO{sub 2}-supported clusters of tantalum were synthesized from adsorbed Ta(CH{sub 2}Ph){sub 5} by treatment in H{sub 2} at 523 K. The surface species were characterized by X-ray absorption spectroscopy (extended X-ray absorption fine structure (EXAFS) spectroscopy and X-ray absorption near edge spectroscopy (XANES)) and ultraviolet-visible spectroscopy. The EXAFS data show that SiOO{sub 2}-supported tantalum clusters were characterized by a Ta-Ta coordination number of approximately 2, consistent with the presence of tritantalum clusters, on average. When these were reduced in H{sub 2} and reoxidized in O{sub 2}, the cluster nuclearity remained essentially unchanged, although reduction and oxidation occurred, respectively, as shown by XANES and UV-vis spectra; in the reoxidation, the tantalum oxidation state change was approximately two electronic charges per tritantalum cluster. The data demonstrate an analogy between the chemistry of group 5 metals on the SiO{sub 2} support and their chemistry in solution, as determined by the group of Cotton.

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

    SciTech Connect

    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.

  4. Technology Development for the Constellation-X Spectroscopy X-Ray Telescope

    NASA Technical Reports Server (NTRS)

    Petre, Robert; Lehan, John; O'Dell, Stephen; Owens, Scott; Reid, Paul B.; Saha, Timo; Stewart, Jeff; Jones, William D.; Zhang, William

    2005-01-01

    The Constellation-X Spectroscopy X-ray Telescope (SXT) is a large diameter, high throughput, grazing incidence imaging mirror system, designed to perform high sensitivity spectroscopy of cosmic X-ray sources in the 0.2-10.0 keV band. The baseline effective area requirement is -3 m# at 1 keV. The system-level angular-resolution requirement is a 15-arcseconds half-power diameter, with a 5-arcsecond goal. The effective area is attained through a modular design, involving the nesting of many confocal, thin-walled Wolter I mirror segments. Considerable progress has been made in developing thin, thermally formed, glass mirror substrates that meet or better the angular-resolution requirement. Several approaches to mounting and aligning reflector segments into a mirror system are under investigation. We report here on the progress of the SXT technology development program toward reaching the performance goals.

  5. X-ray spectroscopy of the photosynthetic oxygen-evolving complex

    SciTech Connect

    Sauer, Ken; Yano, Junko; Yachandra, Vittal K

    2007-04-05

    Water oxidation to dioxygen in photosynthesis is catalyzed by a Mn4Ca cluster with O bridging in Photosystem II (PS II) of plants, algae and cyanobacteria. A variety of spectroscopic methods have been applied to analyzing the participation of the complex. X-ray spectroscopy is particularly useful because it is element-specific, and because it can reveal important structural features of the complex with high accuracy and identify the participation of Mn in the redox chemistry. Following a brief history of the application of X-ray spectroscopy to PS II, an overview of newer results will be presented and a description of the present state of our knowledge based on this approach.

  6. X-ray absorption spectroscopy of the cubic and hexagonal polytypes of zinc sulfide B. Gilbert,1,

    E-print Network

    Haskel, Daniel

    X-ray absorption spectroscopy of the cubic and hexagonal polytypes of zinc sulfide B. Gilbert,1 Received 18 June 2002; published 26 December 2002 We investigate the sensitivity of x-ray absorption. Experimental spectra and multiple-scattering calculations are reported at the major absorption edges

  7. High-pressure x-ray diffraction and Raman spectroscopy of ice VIII Yukihiro Yoshimura,a

    E-print Network

    Stewart, Sarah T.

    of continuing interest. At least 15 different stable and meta- stable forms e.g., ice Ih,Ic­XII, lowHigh-pressure x-ray diffraction and Raman spectroscopy of ice VIII Yukihiro Yoshimura,a Sarah T dynamics of ice VIII. The x-ray measurements show that the pressure-volume relations remain smooth up to 23

  8. Toward Femtosecond X-ray Spectroscopy at the Advanced Light Source

    SciTech Connect

    Chong, Henry Herng Wei

    2004-04-16

    The realization of tunable, ultrashort pulse x-ray sources promises to open new venues of science and to shed new light on long-standing problems in condensed matter physics and chemistry. Fundamentally new information can now be accessed. Used in a pump-probe spectroscopy, ultrashort x-ray pulses provide a means to monitor atomic rearrangement and changes in electronic structure in condensed-matter and chemical systems on the physically-limiting time-scales of atomic motion. This opens the way for the study of fast structural dynamics and the role they play in phase transitions, chemical reactions and the emergence of exotic properties in materials with strongly interacting degrees of freedom. The ultrashort pulse x-ray source developed at the Advanced Light Source at the Lawrence Berkeley Laboratory is based on electron slicing in storage rings, and generates {approx}100 femtosecond pulses of synchrotron radiation spanning wavelengths from the far-infrared to the hard x-ray region of the electromagnetic spectrum. The tunability of the source allows for the adaptation of a broad range of static x-ray spectroscopies to useful pump-probe measurements. Initial experiments are attempted on transition metal complexes that exhibit relatively large structural changes upon photo-excitation and which have excited-state evolution determined by strongly interacting structural, electronic and magnetic degrees of freedom. Specifically, iron(II) complexes undergo a spin-crossover transition upon optical irradiation. The dynamics of the transition involve a metal-to-ligand charge transfer, a {Delta}S=2 change in magnetic moment and 10% bond dilation in the first coordination shell of the iron. Studies of the electronic dynamics are studied with time-resolved optical absorption measurements. The current progress of time-resolved structural studies to complete the picture of the spin-crossover transition is presented.

  9. The Study of Nanocrystalline Cerium Oxide by X-Ray Absorption Spectroscopy

    Microsoft Academic Search

    Ponnusamy Nachimuthu; Wen-Chen Shih; Ru-Shi Liu; Ling-Yun Jang; Jin-Ming Chen

    2000-01-01

    X-ray absorption spectroscopy has been used to study the structural and electronic properties of cerium atoms in nano-crystalline cerium oxide. These nanocrystalline cerium oxides were prepared by precipitation followed by the aging process. To increase the particle size, the as-prepared cerium oxides were calcined at various temperatures. The nanocrystalline phase was retained, even when the samples were calcined at 600°C.

  10. A microstrip germanium detector for position-sensitive X-ray spectroscopy

    Microsoft Academic Search

    D. Protic; T. Stohlker; H. F. Ebeyer; J. Bojowald; G. Borchert; A. Gumberidze; A. Hamacher; C. Kozhuharov; X. Ma; I. Mohos

    2001-01-01

    For the current X-ray spectroscopy program at the ESR storage ring (GSI-Darmstadt), a position-sensitive germanium detector system was completed. The position-sensitive structure of the detector was realized on an area of 47×23.4 mm by an array of 200 strips (200 ?m wide and 23.4 mm long) separated by 35-?m-wide grooves etched through boron implanted contact. The thickness of the detector,

  11. Repair of fractured framework: scanning electron microscopy and energy dispersive X-ray spectroscopy.

    PubMed

    Maalhagh-Fard, Ahmad; Wagner, Warren C

    2004-09-01

    Fractured metal prostheses can be analyzed for possible causes of failure using scanning electron microscopy (SEM). In this study, fractography is used to determine the cause of the failure and whether repair is practical. Energy-dispersive x-ray spectroscopy (EDS) is used to determine composition of the fractured prosthesis so that a repair process can be recommended. The technique is presented for the repair of a titanium framework for an implant-supported overdenture based on the analysis data. PMID:15359153

  12. Cation Distribution in Zn Doped Cobalt Nanoferrites Determined by X-ray Absorption Spectroscopy

    Microsoft Academic Search

    Giuliana Aquilanti; Andrea Cognigni; M. Anis-ur-Rehman

    2011-01-01

    Information on local crystal and electronic structure with elemental specificity is of paramount importance to understand\\u000a many scientific problems. X-ray Absorption Spectroscopy (XAS) is particularly suited for this. Spinel structured ferrites\\u000a exhibit a range of electrical and magnetic properties that make them particularly appealing for many technological applications\\u000a such as permanent magnets, microwave absorbers, catalysts, and chemical sensors. Since the

  13. X-ray and. gamma. -ray spectroscopy of solids under pressure

    SciTech Connect

    Ingalls, R.L.

    1990-04-20

    This report briefly describes our studies of various materials at high pressures by means of x-ray and {gamma}-ray absorption spectroscopy. High pressure provides a very effective means of studying materials. Virtually every property is altered from the color and crystal structure to the electrical and magnetic properties. The fundamental reason, of course, is that the quantum levels depend upon the atomic spacing so that both the electronic and vibrational structure is affected.

  14. Gold nanotags for combined multi-colored Raman spectroscopy and x-ray computed tomography

    Microsoft Academic Search

    Ming Xiao; James Nyagilo; Veera Arora; Padmakar Kulkarni; Dongsheng Xu; Xiankai Sun; Digant P. Davé

    2010-01-01

    Multi-color gold-nanoparticle-based tags (nanotags) are synthesized for combined surface-enhanced Raman spectroscopy (SERS) and x-ray computed tomography (CT). The nanotags are synthesized with quasi-spherical gold nanoparticles encoded with a reporter dye (color), each with a unique Raman spectrum. A library of nanotags with six different colors were synthesized for a range of gold nanoparticle sizes and an optimum size has been

  15. Heavy-Ion Spectroscopy with X-Ray Lasers at GSI

    NASA Astrophysics Data System (ADS)

    Zielbauer, B.; Ecker, B.; Neumayer, P.; Cassou, K.; Daboussi, S.; Guilbaud, O.; Kazamias, S.; Ros, D.; Kuehl, T.; Eisenbarth, U.; Goette, S.; Winters, D.; Bagnoud, V.; Stoehlker, T.

    Different pumping schemes for soft X-ray lasers have been investigated at the PHELIX laser facility, including a double-target seeding approach at 18.9 nm. A technical feasibility study of using a Mo XRL beam of several ?J as an excitation source for heavy-ion spectroscopy in a storage ring has been carried out. XRL photon numbers and the beam transport under ultra-high vacuum conditions over almost 30 m are the major challenges.

  16. X-Ray absorption spectroscopy of transition metal–magnesium hydride thin films

    Microsoft Academic Search

    T. J. Richardson; B. Farangis; J. L. Slack; P. Nachimuthu; R. Perera; N. Tamura; M. Rubin

    2003-01-01

    Mixed metal thin films containing magnesium and a first-row transition element exhibit very large changes in both reflectance and transmittance on exposure to hydrogen gas. Changes in electronic structure and coordination of the magnesium and transition metal atoms during hydrogen absorption were studied using dynamic in situ transmission mode X-ray absorption spectroscopy. Mg K-edge and Ni, Co, and Ti L-edge

  17. X-ray photoelectron spectroscopy study on electrochromic V2O5 thin film

    Microsoft Academic Search

    Wang Zhong-chun; Li Zhi-yong; Chen Xiao-feng; Hu Xing-fang

    1999-01-01

    Nanocrystalline V2O5 thin films were reactively radio-frequency magnetron-sputtered under optimal deposition parameters. Their electrochemical and electrochromic characteristics were investigated by cyclic voltammetry and in-situ monochromatic transmittance measurements. Upon lithium intercalation, V2O5 thin films showed a double electrochromic behavior depending on the wavelength and the intercalation extent. X-ray photoelectron spectroscopy results showed that part of the V5+ in V2O5 was reduced

  18. High Resolution Spectroscopy of the X-Ray Emission of GRBs by IMBOSS on the ISS

    Microsoft Academic Search

    L. Colasanti; L. Piro; L. Pacciani; E. Costa; G. Gandolfi; P. Soffitta; F. Gatti; D. Pergolesi; M. Razeti; R. Vaccarone; G. Testera; M. Pallavicini; A. Ferrari; E. Trussoni; M. Orio; D. McCammon; T. Sanders; M. Galeazzi; A. Szymkowiak; S. Porter; R. Kelley

    2003-01-01

    The IMBOSS (Interstellar\\/Intergalactic Medium and gamma-ray Burst Observatory and Spectroscopy Survey) is an experiment proposed to fly on the ISS (International Space Station), in order to perform an all-sky survey to study the diffuse X-ray emission and to measure the spectra of Gamma-Ray Bursts (GRB) with high energy resolution in the 0.1-10 keV energy range. In a 3-year mission, the

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

    SciTech Connect

    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. EUV and hard x-ray instruments on board the Spanish Minisat 01 mission

    NASA Astrophysics Data System (ADS)

    Gimenez, Alvaro

    1998-11-01

    Minisat 01 is the first of a series of small satellites developed by INTA in Spain. In this case, it as a multi- purpose scientific mission. It was successfully launched on April 21 of last year using a Pegasus rocket. Minisat 01 caries on-board a payload with two astronomical instruments: EURD and LEGRI. EURD is a high sensitivity double spectrometer for the measurement of diffuse cosmic radiation in the extreme UV range, from 350 to 1100 angstrom. LEGRI is a hard x-ray imaging telescope with a coded mask and an array of HgI(subscript 2) and CdZnTe detectors. News about the performance of Minisat 01 in orbit and its scientific results are presented together with a brief description of the instrumental and their main objectives. The continuation of the program is ensured by several future Minisat missions, now under development or study.

  1. Soft X-ray Spectroscopy of the Cygnus Loop Supernova Remnant

    E-print Network

    Randall L. McEntaffer; Webster Cash

    2008-01-29

    The Cygnus X-ray Emission Spectroscopic Survey (CyXESS) sounding rocket payload was launched from White Sands Missile Range on 2006 November 20 and obtained a high resolution spectrum of the Cygnus Loop supernova remnant in the soft X-rays. The novel X-ray spectrograph incorporated a wire-grid collimator feeding an array of gratings in the extreme off-plane mount which ultimately dispersed the spectrum onto Gaseous Electron Multiplier (GEM) detectors. This instrument recorded 65 seconds of usable data between 43-49.5 \\AA in two prominent features. The first feature near 45 \\AA is dominated by the He-like triplet of \\ion{O}{7} in second order with contributions from \\ion{Mg}{10} and \\ion{Si}{9}-\\ion{Si}{12} in first order, while the second feature near 47.5 \\AA is first order \\ion{S}{9} and \\ion{S}{10}. Fits to the spectra give an equilibrium plasma at $\\log(T)=6.2$ ($kT_e=0.14$ keV) and near cosmic abundances. This is consistent with previous observations, which demonstrated that the soft x-ray emission from the Cygnus Loop is dominated by interactions between the initial blast wave with the walls of a precursor formed cavity surrounding the Cygnus Loop and that this interaction can be described using equilibrium conditions.

  2. Algorithms for a hand-held miniature x-ray fluorescence analytical instrument

    SciTech Connect

    Elam, W.T.; Newman, D.; Ziemba, F. [and others

    1998-12-31

    The purpose of this joint program was to provide technical assistance with the development of a Miniature X-ray Fluorescence (XRF) Analytical Instrument. This new XRF instrument is designed to overcome the weaknesses of spectrometers commercially available at the present time. Currently available XRF spectrometers (for a complete list see reference 1) convert spectral information to sample composition using the influence coefficients technique or the fundamental parameters method. They require either a standard sample with composition relatively close to the unknown or a detailed knowledge of the sample matrix. They also require a highly-trained operator and the results often depend on the capabilities of the operator. In addition, almost all existing field-portable, hand-held instruments use radioactive sources for excitation. Regulatory limits on such sources restrict them such that they can only provide relatively weak excitation. This limits all current hand-held XRF instruments to poor detection limits and/or long data collection times, in addition to the licensing requirements and disposal problems for radioactive sources. The new XRF instrument was developed jointly by Quantrad Sensor, Inc., the Naval Research Laboratory (NRL), and the Department of Energy (DOE). This report describes the analysis algorithms developed by NRL for the new instrument and the software which embodies them.

  3. A von Hamos x-ray spectrometer based on a segmented-type diffraction crystal for single-shot x-ray emission spectroscopy and time-resolved resonant inelastic x-ray scattering studies

    NASA Astrophysics Data System (ADS)

    Szlachetko, J.; Nachtegaal, M.; de Boni, E.; Willimann, M.; Safonova, O.; Sa, J.; Smolentsev, G.; Szlachetko, M.; van Bokhoven, J. A.; Dousse, J.-Cl.; Hoszowska, J.; Kayser, Y.; Jagodzinski, P.; Bergamaschi, A.; Schmitt, B.; David, C.; Lücke, A.

    2012-10-01

    We report on the design and performance of a wavelength-dispersive type spectrometer based on the von Hamos geometry. The spectrometer is equipped with a segmented-type crystal for x-ray diffraction and provides an energy resolution in the order of 0.25 eV and 1 eV over an energy range of 8000 eV-9600 eV. The use of a segmented crystal results in a simple and straightforward crystal preparation that allows to preserve the spectrometer resolution and spectrometer efficiency. Application of the spectrometer for time-resolved resonant inelastic x-ray scattering and single-shot x-ray emission spectroscopy is demonstrated.

  4. A von Hamos x-ray spectrometer based on a segmented-type diffraction crystal for single-shot x-ray emission spectroscopy and time-resolved resonant inelastic x-ray scattering studies

    SciTech Connect

    Szlachetko, J. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Institute of Physics, Jan Kochanowski University, 25-406 Kielce (Poland); Nachtegaal, M.; Boni, E. de; Willimann, M.; Safonova, O.; Sa, J.; Smolentsev, G.; Szlachetko, M.; Bergamaschi, A.; Schmitt, B.; David, C.; Luecke, A. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Bokhoven, J. A. van [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Institute for Chemical and Bioengineering, ETH Zurich, 8093 Zuerich (Switzerland); Dousse, J.-Cl.; Hoszowska, J.; Kayser, Y. [Department of Physics, University of Fribourg, 1700 Fribourg (Switzerland); Jagodzinski, P. [University of Technology, Kielce (Poland)

    2012-10-15

    We report on the design and performance of a wavelength-dispersive type spectrometer based on the von Hamos geometry. The spectrometer is equipped with a segmented-type crystal for x-ray diffraction and provides an energy resolution in the order of 0.25 eV and 1 eV over an energy range of 8000 eV-9600 eV. The use of a segmented crystal results in a simple and straightforward crystal preparation that allows to preserve the spectrometer resolution and spectrometer efficiency. Application of the spectrometer for time-resolved resonant inelastic x-ray scattering and single-shot x-ray emission spectroscopy is demonstrated.

  5. Characterization study of GaAs(001) surfaces using ion scattering spectroscopy and x-ray photoelectron spectroscopy

    Microsoft Academic Search

    John T. Wolan; William S. Epling; Gar B. Hoflund

    1997-01-01

    A surface characterization study using ion scattering spectroscopy (ISS) and x-ray photoelectron spectroscopy (XPS) has been performed on solvent cleaned, n-type GaAs(001) substrates before and after cleaning by ion sputtering and annealing. The native oxide layer on this surface contains large amounts of As2O5,As2O3, and Ga2O3 according to XPS with Ga2O3 being the predominant species. Before cleaning C is present

  6. Comparing Compositions of Modern Cast Bronze Sculptures: Optical Emission Spectroscopy Versus x-Ray Fluorescence Spectroscopy

    NASA Astrophysics Data System (ADS)

    Young, M. L.; Dunand, D. C.

    2015-05-01

    Bulk elemental compositions of 74 modern cast bronze sculptures from the collection at the Art Institute of Chicago, the Philadelphia Museum of Art, and the Rodin Museum (Philadelphia, PA) were determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and a handheld x-ray fluorescence (XRF) spectrometer. The elemental compositions of the cast sculptures as measured previously by ICP-OES and presently by XRF are compared: A good match is found between the two methods for the base metal (Cu) and the two majority alloying elements (Zn and Sn). For both ICP-OES and XRF data, when the Zn composition is plotted versus the Sn composition, three discernable clusters are found that are related to the artist, foundry, casting date, and casting method; they consist of (A) high-zinc brass, (B) low-zinc, low-tin brass, and (C) low-zinc, tin bronze. Thus, our study confirms that the relatively fast, nondestructive XRF spectrometry can be used effectively over slower and invasive, but more accurate, ICP-OES to help determine a sculpture's artist, foundry, date of creation, date of casting, and casting method.

  7. A X-Ray Absorption Spectroscopy Study of Manganese Containing Compounds and Photosynthetic Spinach Chloroplasts.

    NASA Astrophysics Data System (ADS)

    Kirby, Jon Allan

    The manganese sites in chloroplasts, long thought to be involved in photosynthetic oxygen evolution have been examined and partially characterized by X-ray Absorption Spectroscopy (XAS) using synchrotron radiation. The local environment about the manganese atoms is estimated from an analysis of the extended X-ray Absorption Fine Structure (EXAFS). Comparisons with and simulations of the manganese EXAFS for several reference compounds leads to a model in which the chloroplast manganese atoms are contained in a binuclear complex similar to di-u-oxo -tetrakis-(2,2'-bipyridine) dimanganese. It is suggested that the partner metal is another manganese. The bridging ligands are most probably oxygen. The remaining manganese ligands are carbon, oxygen, or nitrogen. A roughly linear correlation between the X-ray K edge onset energy and the "coordination charge" of a large number of manganese coordination complexes and compounds has been developed. Entry of the chloroplast manganese edge energy onto this correlation diagram establishes that the active pool of manganese is in an oxidation state greater than +2. If the manganese is in a dimeric form the oxidation states are most probably (II,III). Underlying these results is an extensive data analysis methodology. The method developed involves the use of many different background removal techniques, Fourier transforms and ultimately curve fitting to the modulations in the x-ray absorption cross sections. A large number of model compounds were used to evaluate the analysis method. These analyses are used to show that the two major curve fitting models available are essentially equivalent. Due to its greater versatility, the theoretical model of Teo and Lee is preferred (J. Am. Chem. Soc. (1979), 101, 2815). The results are also used to determine the informational limitations of XAS within the limits of the present understanding of X-ray absorption phenomena by inner shell electrons for atoms with atomic number greater than that of argon.

  8. THE CHANDRA MULTI-WAVELENGTH PROJECT: OPTICAL SPECTROSCOPY AND THE BROADBAND SPECTRAL ENERGY DISTRIBUTIONS OF X-RAY-SELECTED AGNs

    E-print Network

    Trichas, Markos

    From optical spectroscopy of X-ray sources observed as part of the Chandra Multi-wavelength Project (ChaMP), we present redshifts and classifications for a total of 1569 Chandra sources from our targeted spectroscopic ...

  9. Highly multiplexible thermal kinetic inductance detectors for x-ray imaging spectroscopy

    NASA Astrophysics Data System (ADS)

    Ulbricht, Gerhard; Mazin, Benjamin A.; Szypryt, Paul; Walter, Alex B.; Bockstiegel, Clint; Bumble, Bruce

    2015-06-01

    For X-ray imaging spectroscopy, high spatial resolution over a large field of view is often as important as high energy resolution, but current X-ray detectors do not provide both in the same device. Thermal Kinetic Inductance Detectors (TKIDs) are being developed as they offer a feasible way to combine the energy resolution of transition edge sensors with pixel counts approaching CCDs and thus promise significant improvements for many X-ray spectroscopy applications. TKIDs are a variation of Microwave Kinetic Inductance Detectors (MKIDs) and share their multiplexibility: working MKID arrays with 2024 pixels have recently been demonstrated and much bigger arrays are under development. In this work, we present a TKID prototype, which is able to achieve an energy resolution of 75 eV at 5.9 keV, even though its general design still has to be optimized. We further describe TKID fabrication, characterization, multiplexing, and working principle and demonstrate the necessity of a data fitting algorithm in order to extract photon energies. With further design optimizations, we expect to be able to improve our TKID energy resolution to less than 10 eV at 5.9 keV.

  10. Multidimensional x-ray spectroscopy of valence and core excitations in cysteine

    PubMed Central

    Biggs, Jason D.; Zhang, Yu; Healion, Daniel; Mukamel, Shaul

    2013-01-01

    Several nonlinear spectroscopy experiments which employ broadband x-ray pulses to probe the coupling between localized core and delocalized valence excitation are simulated for the amino acid cysteine at the K-edges of oxygen and nitrogen and the K- and L-edges of sulfur. We focus on two-dimensional (2D) and 3D signals generated by two- and three-pulse stimulated x-ray Raman spectroscopy (SXRS) with frequency-dispersed probe. We show how the four-pulse x-ray signals \\documentclass[12pt]{minimal}\\begin{document}${\\bm k}_\\mathrm{I} =-{\\bm k} _1+{\\bm k} _2+{\\bm k} _3$\\end{document}kI=?k1+k2+k3 and \\documentclass[12pt]{minimal}\\begin{document}${\\bm k}_\\mathrm{II} ={\\bm k} _1-{\\bm k} _2+{\\bm k} _3$\\end{document}k II =k1?k2+k3 can give new 3D insight into the SXRS signals. The coupling between valence- and core-excited states can be visualized in three-dimensional plots, revealing the origin of the polarizability that controls the simpler pump-probe SXRS signals. PMID:24981531

  11. Mineral identification in Colombian coals using Mössbauer spectroscopy and X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Fajardo, M.; Mojica, J.; Barraza, J.; Pérez Alcázar, G. A.; Tabares, J. A.

    1999-11-01

    Minerals were identified in three Colombian coal samples from the Southwest of the country using Mössbauer spectroscopy and X-ray diffraction. Original and sink separated coal fractions of specific gravity 1.40 and 1.60 with particle size less than 600 µm were used in the study. Using Mössbauer spectroscopy, the minerals identified in the original coal samples were pyrite jarosite, ankerite, illite and ferrous sulfate, whereas by means of X-ray diffraction, minerals identified were kaolinite, quartz, pyrite, and jarosite. Differences in mineral composition were found in the original and sink separated fractions using both techniques. Mössbauer spectra show that the mineral phases in low concentrations such as illite, ankerite and ferrous sulfate do not always appear in the spectra of sink coals, despite of those minerals occurring in the original coal, due to the fact that they are associated with the organic matter and not liberated in the grinding process. X-ray results show that the peak intensity grows as the specific gravity is increased indicating that the density separation method could be an effective process to clean coal.

  12. Diffusion of TiN into aluminum films measured by soft x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Schuler, T. M.; Ederer, D. L.; Ruzycki, N.; Glass, G.; Hollerman, W. A.; Moewes, A.; Kuhn, M.; Callcott, T. A.

    2001-07-01

    Understanding the atomic bonding properties at the interface between thin films is crucial to a number of key modern technical devices, including integrated circuits, magnetic disk read/write heads, batteries, and solar cells. Semi-conducting materials such as titanium nitride (TiNx) are widely used in the manufacturing of modern electronics, requiring a wealth of information about its electronic structure. We present data from soft x-ray emission and absorption experiments involving a sample consisting of a 40 nm TiN layer on top of an aluminum film 550 nm thick. Soft x-ray emission spectroscopy (XES) and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy are tools that provide a non-destructive, atomic site-specific probe of the interface, where the electronic structure of the material can be mapped out element by element. From these measurements, we show that the Ti and the N diffuse into the Al film to form an equivalent material depth of about 4.5 nm, and the NEXAF structure reveals that the nitrogen has probably formed AlN, and the Ti has also diffused to form a titanium-aluminum compound.

  13. Magnetic ZnFe2O4 nanoferrites studied by X-ray magnetic circular dichroism and Mössbauer spectroscopy

    Microsoft Academic Search

    S. J. Stewart; S. J. A. Figueroa; M. B. Sturla; R. B. Scorzelli; F. García; F. G. Requejo

    2007-01-01

    ZnFe2O4 nanoparticles (6 nm) were synthesized by hydrothermal methods. Subsequent mechanical treatment applied to the nanocrystalline material caused an increment of the grain size up to 13 nm. The samples were characterized by X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) at the Fe K edge and 57Fe Mössbauer spectroscopy. The absorption pre-edge features indicate that Fe3+ ions

  14. Magnetic ZnFe 2O 4 nanoferrites studied by X-ray magnetic circular dichroism and Mössbauer spectroscopy

    Microsoft Academic Search

    S. J. Stewart; S. J. A. Figueroa; M. B. Sturla; R. B. Scorzelli; F. García; F. G. Requejo

    2007-01-01

    ZnFe2O4 nanoparticles (6nm) were synthesized by hydrothermal methods. Subsequent mechanical treatment applied to the nanocrystalline material caused an increment of the grain size up to 13nm. The samples were characterized by X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) at the Fe–K edge and 57Fe Mössbauer spectroscopy. The absorption pre-edge features indicate that Fe3+ ions occupy non-centrosymmetric sites.

  15. The use of X?ray absorption spectroscopy for monitoring the thickness of antiwear films from ZDDP

    Microsoft Academic Search

    M. L. Suominen Fuller; L. Rodriguez Fernandez; G. R. Massoumi; W. N. Lennard; M. Kasrai; G. M. Bancroft

    2000-01-01

    X?ray absorption near edge structure (XANES) spectroscopy at the P K?edge was used to monitor ZDDP antiwear film thickness\\u000a with rubbing time. Thermal immersion films of varying thickness were generated from the ZDDP and analysed using XANES spectroscopy\\u000a and the particle induced X?ray emission (PIXE) technique. P K?edge XANES edge jumps and (1s ? np) peak heights of the spectra

  16. An 8x8 pixel IC for X-ray spectroscopy

    SciTech Connect

    Krieger, Bradley; Ewell, Kathryn; Ludewigt, Bernhard A.; Maier, Michael R.; Markovic, Dejan; Milgrome, Oren; Wang, Y. June

    2000-11-03

    An integrated circuit providing 64 channels of low-noise signal processing electronics in an 8x8 pixel arrangement has been developed as part of an integrated silicon detector array for high count-rate x-ray spectroscopy applications. Each pixel features low-noise charge integration, programmable peaking time and gain, and an output driver. The 8x8 pixel IC builds upon our previous development of the XPS chip, a 1-dimensional preamplifier-shaper IC for linear silicon detector arrays. The new pixel design features significant improvements to the shaper and output driver stages, including digital peaking time and gain selection, and a low-power charge driver/receiver design. When operated with a cooled, low-capacitance silicon detector, an energy resolution of {approx} 210 eV FWHM was obtained for 5.89 keV x-rays.

  17. An 8x8 pixel IC for X-ray spectroscopy

    SciTech Connect

    Krieger, Bradley; Ewell, Kathryn; Ludewigt, Bernhard A.; Maier, Michael R.; Markovic, Dejan; Milgrome, Oren; Wang, Y. June

    2000-11-03

    An integrated circuit providing 64 channels of low-noise signal processing electronics in an 8x8 pixel arrangement has been developed as part of an integrated silicon detector array for high count-rate x-ray spectroscopy applications. Each pixel features low-noise charge integration, programmable peaking time and gain, and an output driver. The 8x8 pixel IC builds upon our previous development of the XPS chip, a 1-dimensional preamplifier-shaper IC for linear silicon detector arrays. The new pixel design features significant improvements to the shaper and output driver stages, including digital peaking time and gain selection, and a low-power charge driver/receiver design. When operated with a cooled, low-capacitance silicon detector, an energy resolution of {approx}210 eV FWHM was obtained for 5.89 keV x-rays.

  18. Studies of copper valence states with Cu L3 x-ray-absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Grioni, M.; Goedkoop, J. B.; Schoorl, R.; de Groot, F. M. F.; Fuggle, J. C.; Schäfers, F.; Koch, E. E.; Rossi, G.; Esteva, J.-M.; Karnatak, R. C.

    1989-01-01

    We have used x-ray-absorption spectroscopy to study a series of compounds in which Cu assumes a formal valence between 0 and 3. We find that the shape, the threshold energy, and the intensity of the Cu L3 absorption edge is strongly influenced by the chemical state of the Cu atoms. We use the Cu 2p x-ray-absorption spectra of a large number of Cu compounds, including sulfides, oxides, La-Sr-Cu-O compounds, a phthalocyanine complex, and various minerals to show that the presence of a strong 2p-3d excitonic transition is a fingerprint of the Cu(d9) contribution to the ground state. A simple ionic picture is generally inadequate to describe these compounds.

  19. In situ x-ray photoelectron spectroscopy for electrochemical reactions in ordinary solvents

    SciTech Connect

    Masuda, Takuya [Global Research Center for Environment and Energy Based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS), Tsukuba 305-0044 (Japan) [Global Research Center for Environment and Energy Based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS), Tsukuba 305-0044 (Japan); PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 333-0012 (Japan); Yoshikawa, Hideki; Kobata, Masaaki; Kobayashi, Keisuke [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), Sayo, Hyogo 679-5148 (Japan)] [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), Sayo, Hyogo 679-5148 (Japan); Noguchi, Hidenori [Global Research Center for Environment and Energy Based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS), Tsukuba 305-0044 (Japan) [Global Research Center for Environment and Energy Based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS), Tsukuba 305-0044 (Japan); PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 333-0012 (Japan); Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044 (Japan); Kawasaki, Tadahiro [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603 (Japan)] [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8603 (Japan); Uosaki, Kohei [Global Research Center for Environment and Energy Based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS), Tsukuba 305-0044 (Japan) [Global Research Center for Environment and Energy Based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS), Tsukuba 305-0044 (Japan); Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044 (Japan)

    2013-09-09

    In situ electrochemical X-ray photoelectron spectroscopy (XPS) apparatus, which allows XPS at solid/liquid interfaces under potential control, was constructed utilizing a microcell with an ultra-thin Si membrane, which separates vacuum and a solution. Hard X-rays from a synchrotron source penetrate into the Si membrane surface exposed to the solution. Electrons emitted at the Si/solution interface can pass through the membrane and be analyzed by an analyzer placed in vacuum. Its operation was demonstrated for potential-induced Si oxide growth in water. Effect of potential and time on the thickness of Si and Si oxide layers was quantitatively determined at sub-nanometer resolution.

  20. RXTE timing and spectroscopy of a black hole X-ray binary in outburst

    NASA Technical Reports Server (NTRS)

    Miller, Jon; Swank, Jean (Technical Monitor)

    2005-01-01

    Under this program, RXTE observed the Galactic black hole candidate X-ray binary H1743-322. Observations were made simultaneously in the X-ray and radio bands with Chandra and the VLA, respectively. First results from this multi-wavelength study have been reported in two papers published in refereed journals, one focusing on timing results and the other focusing on spectroscopy. The timing studies revealed high frequency QPOs at approximately 180 Hz and 240 Hz, likely in a 2:3 frequency ratio as predicted by some models. The RXTE spectra were remarkable in that they showed no evidence of disk reflection or line emission, both of which are expected in black holes.

  1. Note: Sample chamber for in situ x-ray absorption spectroscopy studies of battery materials

    NASA Astrophysics Data System (ADS)

    Pelliccione, C. J.; Timofeeva, E. V.; Katsoudas, J. P.; Segre, C. U.

    2014-12-01

    In situ x-ray absorption spectroscopy (XAS) provides element-specific characterization of both crystalline and amorphous phases and enables direct correlations between electrochemical performance and structural characteristics of cathode and anode materials. In situ XAS measurements are very demanding to the design of the experimental setup. We have developed a sample chamber that provides electrical connectivity and inert atmosphere for operating electrochemical cells and also accounts for x-ray interactions with the chamber and cell materials. The design of the sample chamber for in situ measurements is presented along with example XAS spectra from anode materials in operating pouch cells at the Zn and Sn K-edges measured in fluorescence and transmission modes, respectively.

  2. Hard x-ray photoelectron spectroscopy using an environmental cell with silicon nitride membrane windows

    NASA Astrophysics Data System (ADS)

    Tsunemi, Eika; Watanabe, Yoshio; Oji, Hiroshi; Cui, Yi-Tao; Son, Jin-Young; Nakajima, Atsushi

    2015-06-01

    We applied hard x-ray photoelectron spectroscopy (HAXPES) to a sample under ambient pressure conditions using an environmental cell with an approximately 24 nm-thick SiNx membrane window. As a model chemical substance, europium (II) iodide (EuI2) sealed in the cell with argon gas was investigated with HAXPES to identify the chemical species present inside the cell. The optical and morphological properties of the sample within the cell were measured with optical and fluorescent microscopy, scanning electron microscopy, cathodoluminescence, and energy dispersive x-ray spectrometry. We confirmed the effectiveness of the gas barrier properties of the cell with the SiNx window and demonstrated its applicability to various other optical and electron measurements as well as HAXPES.

  3. High average power, highly brilliant laser-produced plasma source for soft X-ray spectroscopy.

    PubMed

    Mantouvalou, Ioanna; Witte, Katharina; Grötzsch, Daniel; Neitzel, Michael; Günther, Sabrina; Baumann, Jonas; Jung, Robert; Stiel, Holger; Kanngiesser, Birgit; Sandner, Wolfgang

    2015-03-01

    In this work, a novel laser-produced plasma source is presented which delivers pulsed broadband soft X-radiation in the range between 100 and 1200 eV. The source was designed in view of long operating hours, high stability, and cost effectiveness. It relies on a rotating and translating metal target and achieves high stability through an on-line monitoring device using a four quadrant extreme ultraviolet diode in a pinhole camera arrangement. The source can be operated with three different laser pulse durations and various target materials and is equipped with two beamlines for simultaneous experiments. Characterization measurements are presented with special emphasis on the source position and emission stability of the source. As a first application, a near edge X-ray absorption fine structure measurement on a thin polyimide foil shows the potential of the source for soft X-ray spectroscopy. PMID:25832284

  4. Inner-shell photoionization spectroscopy on deposited metal clusters using soft x-ray synchrotron radiation: an experimental setup.

    PubMed

    Peters, S; Peredkov, S; Balkaya, B; Ferretti, N; Savci, A; Vollmer, A; Neeb, M; Eberhardt, W

    2009-12-01

    Exploration of mass-selected clusters by soft x-ray synchrotron radiation is well suited to receive element specific information on clusters in contact with a support and to systematically follow the evolution of size-dependent electronic and geometrical properties from the smallest clusters toward the bulk. Here we describe an experimental setup, which combines cluster synthesis, mass selection, soft landing, ultrahigh vacuum transfer, and photoionization experiments such as x-ray photoelectron spectroscopy, x-ray absorption, and Auger electron spectroscopy. First spectroscopic results and experimental conditions are briefly discussed for Cu(19) deposited onto the natural oxide layer of a Si-wafer surface. PMID:20059169

  5. Electronic Properties of Hydrogen Storage Materials with Photon-in/Photon-out Soft-X-Ray Spectroscopy

    SciTech Connect

    Guo, Jinghua

    2008-09-22

    The applications of resonant soft X-ray emission spectroscopy on a variety of carbon systems have yielded characteristic fingerprints. With high-resolution monochromatized synchrotron radiation excitation, resonant inelastic X-ray scattering has emerged as a new source of information about electronic structure and excitation dynamics. Photon-in/photon-out soft-X-ray spectroscopy is used to study the electronic properties of fundamental materials, nanostructure, and complex hydrides and will offer potential in-depth understanding of chemisorption and/or physisorption mechanisms of hydrogen adsorption/desorption capacity and kinetics.

  6. Effect of iron oxide reductive dissolution on the transformation and immobilization of arsenic in soils: New insights from X-ray photoelectron and X-ray absorption spectroscopy.

    PubMed

    Fan, Jian-Xin; Wang, Yu-Jun; Liu, Cun; Wang, Li-Hua; Yang, Ke; Zhou, Dong-Mei; Li, Wei; Sparks, Donald L

    2014-08-30

    The geochemical behavior and speciation of arsenic (As) in paddy soils is strongly controlled by soil redox conditions and the sequestration by soil iron oxyhydroxides. Hence, the effects of iron oxide reductive dissolution on the adsorption, transformation and precipitation of As(III) and As(V) in soils were investigated using batch experiments and synchrotron based techniques to gain a deeper understanding at both macroscopic and microscopic scales. The results of batch sorption experiments revealed that the sorption capacity of As(V) on anoxic soil was much higher than that on control soil. Synchrotron based X-ray fluorescence (?-XRF) mapping studies indicated that As was heterogeneously distributed and was mainly associated with iron in the soil. X-ray absorption near edge structure (XANES), micro-X-ray absorption near edge structure (?-XANES) and X-ray photoelectron spectroscopy (XPS) analyses revealed that the primary speciation of As in the soil is As(V). These results further suggested that, when As(V) was introduced into the anoxic soil, the rapid coprecipitation of As(V) with ferric/ferrous ion prevented its reduction to As(III), and was the main mechanism controlling the immobilization of As. This research could improve the current understanding of soil As chemistry in paddy and wetland soils. PMID:25064258

  7. Focal plane instrumentation for the Wide-Field X-ray Telescope

    E-print Network

    Bautz, Marshall W.

    The three X-ray imaging focal planes of the Wide-Field X-ray Telescope (WFXT) Mission will each have a field of view up to 1 degree square, pixel pitch smaller than 1 arcsec, excellent X-ray detection efficiency and spectral ...

  8. Use of X-Ray Absorption Spectroscopy to Monitor the Kinetics of Metal Sorption Reactions at the Soil/Water Interface

    E-print Network

    Sparks, Donald L.

    Use of X-Ray Absorption Spectroscopy to Monitor the Kinetics of Metal Sorption Reactions on the surface coordination environment of Ni sorbed onto clays and aluminum oxides using X-ray absorption fine

  9. Excited-state molecular structures captured by X-ray transient absorption spectroscopy: a decade and beyond.

    PubMed

    Chen, Lin X; Zhang, Xiaoyi; Lockard, Jenny V; Stickrath, Andrew B; Attenkofer, Klaus; Jennings, Guy; Liu, Di-Jia

    2010-03-01

    Transient molecular structures along chemical reaction pathways are important for predicting molecular reactivity, understanding reaction mechanisms, as well as controlling reaction pathways. During the past decade, X-ray transient absorption spectroscopy (XTA, or LITR-XAS, laser-initiated X-ray absorption spectroscopy), analogous to the commonly used optical transient absorption spectroscopy, has been developed. XTA uses a laser pulse to trigger a fundamental chemical process, and an X-ray pulse(s) to probe transient structures as a function of the time delay between the pump and probe pulses. Using X-ray pulses with high photon flux from synchrotron sources, transient electronic and molecular structures of metal complexes have been studied in disordered media from homogeneous solutions to heterogeneous solution-solid interfaces. Several examples from the studies at the Advanced Photon Source in Argonne National Laboratory are summarized, including excited-state metalloporphyrins, metal-to-ligand charge transfer (MLCT) states of transition metal complexes, and charge transfer states of metal complexes at the interface with semiconductor nanoparticles. Recent developments of the method are briefly described followed by a future prospective of XTA. It is envisioned that concurrent developments in X-ray free-electron lasers and synchrotron X-ray facilities as well as other table-top laser-driven femtosecond X-ray sources will make many breakthroughs and realise dreams of visualizing molecular movies and snapshots, which ultimately enable chemical reaction pathways to be controlled. PMID:20164647

  10. Excited-state molecular structures captured by x-ray transient absorption spectroscopy : a decade and beyond.

    SciTech Connect

    Chen, L. X.; Zhang, X.; Lockard, J. V.; Stickrath, A. B.; Attenkofer, K.; Jennings, G.; Liu, D.-J.; Northwestern Univ.

    2010-03-02

    Transient molecular structures along chemical reaction pathways are important for predicting molecular reactivity, understanding reaction mechanisms, as well as controlling reaction pathways. During the past decade, X-ray transient absorption spectroscopy (XTA, or LITR-XAS, laser-initiated X-ray absorption spectroscopy), analogous to the commonly used optical transient absorption spectroscopy, has been developed. XTA uses a laser pulse to trigger a fundamental chemical process, and an X-ray pulse(s) to probe transient structures as a function of the time delay between the pump and probe pulses. Using X-ray pulses with high photon flux from synchrotron sources, transient electronic and molecular structures of metal complexes have been studied in disordered media from homogeneous solutions to heterogeneous solution-solid interfaces. Several examples from the studies at the Advanced Photon Source in Argonne National Laboratory are summarized, including excited-state metalloporphyrins, metal-to-ligand charge transfer (MLCT) states of transition metal complexes, and charge transfer states of metal complexes at the interface with semiconductor nanoparticles. Recent developments of the method are briefly described followed by a future prospective of XTA. It is envisioned that concurrent developments in X-ray free-electron lasers and synchrotron X-ray facilities as well as other table-top laser-driven femtosecond X-ray sources will make many breakthroughs and realise dreams of visualizing molecular movies and snapshots, which ultimately enable chemical reaction pathways to be controlled.

  11. Isotope and Temperature Effects in Liquid Water Probed by X-RayAbsorption and Resonant X-Ray Emission Spectroscopy

    SciTech Connect

    Fuchs, O.; Zharnikov, M.; Weinhardt, L.; Blum, M.; Weigand, M.; Zubavichus, Y.; Bar, M.; Maier, F.; Denlinger, J.D.; Heske, C.; Grunze,M.; Umbach, E.

    2007-03-10

    High-resolution x-ray absorption and emission spectra ofliquid water exhibit a strong isotope effect. Further, the emissionspectra show a splitting of the 1b1 emission line, a weak temperatureeffect, and a pronounced excitation-energy dependence. They can bedescribed as a superposition of two independent contributions. Bycomparing with gasphase, ice, and NaOH/NaOD, we propose that the twocomponents are governed by the initial state hydrogen bondingconfiguration and ultrafast dissociation on the time scale of the O 1score hole decay.

  12. Ultrafast soft X-ray photoelectron spectroscopy at liquid water microjets.

    PubMed

    Faubel, M; Siefermann, K R; Liu, Y; Abel, B

    2012-01-17

    Since the pioneering work of Kai Siegbahn, electron spectroscopy for chemical analysis (ESCA) has been developed into an indispensable analytical technique for surface science. The value of this powerful method of photoelectron spectroscopy (PES, also termed photoemission spectroscopy) and Siegbahn's contributions were recognized in the 1981 Nobel Prize in Physics. The need for high vacuum, however, originally prohibited PES of volatile liquids, and only allowed for investigation of low-vapor-pressure molecules attached to a surface (or close to a surface) or liquid films of low volatility. Only with the invention of liquid beams of volatile liquids compatible with high-vacuum conditions was PES from liquid surfaces under vacuum made feasible. Because of the ubiquity of water interfaces in nature, the liquid water-vacuum interface became a most attractive research topic, particularly over the past 10 years. PES studies of these important aqueous interfaces remained significantly challenging because of the need to develop high-pressure PES methods. For decades, ESCA or PES (termed XPS, for X-ray photoelectron spectroscopy, in the case of soft X-ray photons) was restricted to conventional laboratory X-ray sources or beamlines in synchrotron facilities. This approach enabled frequency domain measurements, but with poor time resolution. Indirect access to time-resolved processes in the condensed phase was only achieved if line-widths could be analyzed or if processes could be related to a fast clock, that is, reference processes that are fast enough and are also well understood in the condensed phase. Just recently, the emergence of high harmonic light sources, providing short-wavelength radiation in ultrashort light pulses, added the dimension of time to the classical ESCA or XPS technique and opened the door to (soft) X-ray photoelectron spectroscopy with ultrahigh time resolution. The combination of high harmonic light sources (providing radiation with laserlike beam qualities) and liquid microjet technology recently enabled the first liquid interface PES experiments in the IR/UV-pump and extreme ultraviolet-probe (EUV-probe) configuration. In this Account, we highlight features of the technology and a number of recent applications, including extreme states of matter and the discovery and detection of short-lived transients of the solvated electron in water. Properties of the EUV radiation, such as its controllable polarization and features of the liquid microjet, will enable unique experiments in the near future. PES measures electron binding energies and angular distributions of photoelectrons, which comprise unique information about electron orbitals and their involvement in chemical bonding. One of the future goals is to use this information to trace molecular orbitals, over time, in chemical reactions or biological transformations. PMID:22075058

  13. Mineralogical and spectroscopic investigation of enstatite chondrites by X-ray diffraction and infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Izawa, M. R.; King, P. L.; Flemming, R. L.; Peterson, R. C.; McCausland, P. J.

    2009-05-01

    Reflectance spectroscopy of well-characterized meteorites provides an important means of linking meteorites to potential parent objects; an important objective in meteoritics research. There is a lack of such sample- correlated spectroscopic and mineralogical data sets in the literature to date. In an effort to improve this situation, the bulk mineralogy and infrared reflectance spectra of 13 enstatite chondrite meteorite finds, spanning the full range of textural alteration grades in both EL and EH classes have been investigated, including eleven recovered from the Antarctic and one from Northwest Africa. Rietveld refinement of high- resolution powder X-ray diffraction (XRD) data was used to identify the major mineral phases and quantify their modal abundances. The mineralogy and modes agree well with those of well-documented enstatite chondrites. Terrestrial weathering products such as Fe-oxyhydroxides, gypsum, and carbonates also occur in most of the meteorites from Antarctica. The mineral abundances determined via Rietveld refinement have been used to calculate model grain densities for each meteorite (i.e. density of the solid phases). Bulk magnetic susceptibility measurements combined with modal mineralogy reveal that as terrestrial weathering increases, both grain density and bulk susceptibility decrease. Sample-correlated thermal infrared (400-4500 cm-1, 2-25 ?m) biconical (Diffuse) Reflectance Infrared Fourier Transform Spectroscopy data were collected for each meteorite to facilitate comparison with remote sensing data. The meteorite spectra are dominated by features corresponding to enstatite. Terrestrial weathering manifests itself as a broad, asymmetric H2O band centered near ~3400 cm-1, analogous to the "3 ?m water of hydration feature" recognized in asteroid spectra, particularly from the enigmatic W-type asteroids. Additional sharp features superimposed on this band, as well as the sharpness of an asymmetric feature related to bound molecular water at ~1625 cm-1 correlate with the degree of weathering of the meteorites. These reflectance IR data provide an analog for remotely-sensed IR spectra from water-bearing asteroid regoliths and point to the need for instruments with much higher spectral resolution to identify structurally- bound water in asteroid regolith.

  14. The Study of Nanocrystalline Cerium Oxide by X-Ray Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Nachimuthu, Ponnusamy; Shih, Wen-Chen; Liu, Ru-Shi; Jang, Ling-Yun; Chen, Jin-Ming

    2000-02-01

    X-ray absorption spectroscopy has been used to study the structural and electronic properties of cerium atoms in nano-crystalline cerium oxide. These nanocrystalline cerium oxides were prepared by precipitation followed by the aging process. To increase the particle size, the as-prepared cerium oxides were calcined at various temperatures. The nanocrystalline phase was retained, even when the samples were calcined at 600°C. The analyses of X-ray absorption near edge structures (XANES) for cerium oxides show that the increase in the relative intensity of the transition to 2p4f15d*L final state and its transition energy shifts toward higher energy are due to the increase in covalence between cerium and oxide ligands with increasing particle size. The extended X-ray absorption fine structure (EXAFS) results for cerium oxide show that the third Ce-O shell is degraded and the coordination number around cerium is decreased, resulting in a decrease in the bond distances of RCe-O and RCe-Ce for particle size <15 nm. However, when the particle size is increased, the third Ce-O shell started growing and the coordination number around cerium attained normal coordination. The present results provide evidence for the formation of nanocrystalline cerium oxide prepared by precipitation followed by the aging process.

  15. Local structure and dynamics of hemeproteins by X-ray absorption near edge structure spectroscopy.

    PubMed

    Arcovito, Alessandro; della Longa, Stefano

    2012-07-01

    X-ray absorption near edge structure (XANES) spectroscopy is a synchrotron radiation technique sensitive to the local structure and dynamics around the metal site of a heme containing protein. Advances in detection techniques and theoretical/computational platforms in the last 15 years allowed the use of XANES as a quantitative probe of the key structural determinants driving functional changes, both in a concerted way with protein crystallography and EXAFS (extended X-ray absorption fine structure), or as a stand-alone method to apply in the crystal state as well as in solution. Moreover, the local dynamics of the heme site has been deeply investigated, on one hand, coupling XANES to classical photolysis experiments at cryogenic temperatures; on the other hand, the intrinsic property of the synchrotron radiation to induce radiolysis events, has been exploited to investigate specific cryotrapped intermediates, using X-rays both as a pump and a probe. Insights on the XANES method and some specific examples are presented to illustrate these topics. PMID:22541673

  16. Tracking electrons and atoms in a photoexcited metalloporphyrin by x-ray transient absorption spectroscopy.

    SciTech Connect

    Chen, L. X.; Zhang, X.; Wasinger, E. C.; Attenkofer, K.; Jennings, G.; Muresan, A. Z.; Lindsey, J. S.; North Carolina State

    2007-01-01

    Simultaneously tracking electronic and molecular structures of a photoexcited metalloporphyrin, present for only 200 ps in a dilute solution, has been realized using X-ray transient absorption spectroscopy (XTA). Using laser pulses as excitation sources and delayed X-ray pulses as probes, we were able to identify the excited state electronic configuration of a nickel porphyrin as singly occupied 3dx2-y2 and 3dz2 molecular orbitals (MOs) with an energy gap of {approx}2.2 eV, and energy shifts 4pz MOs to 1.5 eV higher relative to that of the ground state, and an expanded porphyrin ring characterized by lengthening of Ni-N and Ni-C bonds. Moreover, kinetic XTA signals at different X-ray photon energies demonstrate the capability for acquiring the correlation and coherence between different optically excited states with the same technique. These results provide guidance for theoretical calculations as well as insightful understanding of optically excited states that play important roles in photochemical processes.

  17. X-ray Intensity Fluctuation Spectroscopy Studies of Near-Atomic-Scale Disorder

    NASA Astrophysics Data System (ADS)

    Brauer, Stephan F.

    1996-03-01

    The technique of x-ray intensity fluctuation spectroscopy (XIFS) has been developed and used to make the first observations of the dynamics of critical fluctuations in a binary alloy at equilibrium.( S. Brauer, G.B. Stephenson, M. Sutton, R. Brüning, E. Dufresne, S.G.J. Mochrie, G. Grübel, J. Als-Nielsen, D.L. Abernathy, Phys. Rev. Lett. 74), 2010 (1995). A coherent beam of hard x-rays with 6 × 10^7 photons/second has been formed using a 4 ? m diameter pinhole aperture and a Si(111) crystal monochromator, at undulator beamline 9 (Troika) of the European Synchrotron Radiation Facility. The coherent x-ray beam was used to perform scattering measurements from a single crystal of Fe_3Al near the B2/DO3 order-disorder phase transition (T_c=824.1 K). Below T_c, static speckle patterns were observed near the (1/2 1/2 1/2) superlattice reflection, arising from antiphase domains in the ordered phase. Above Tc however, the scattered intensity was not constant but fluctuated in time. From the intensity time-correlation functions we deduce short-range order correlation times in the range 500-1600 seconds for temperatures 0.15-0.55 K above T_c. These results point the way to future studies of equilibrium dynamics using XIFS techniques.

  18. CHANDRA GRATING SPECTROSCOPY OF THE Be/X-RAY BINARY 1A 0535+262

    SciTech Connect

    Reynolds, Mark T.; Miller, Jon M., E-mail: markrey@umich.ed [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)

    2010-11-10

    We present Chandra HETGS spectroscopy of the Be/X-ray binary 1A 0535+262 obtained during the 2009/2010 giant outburst. These are the first CCD grating spectra of this type of system during a giant outburst. Our spectra reveal a number of lines including a narrow Fe K{alpha} emission line with an FWHM of {approx}5000 km s{sup -1}. For the first time, we detect the presence of a highly ionized outflow in a Be/X-ray binary. Assuming that the line is He-like Fe XXV, fits with a simple Gaussian imply an outflow velocity of {approx}1500 km s{sup -1}. However, self-consistent photoionization modeling with XSTAR suggests that Fe XXIII-XXIV must also contribute. In this case, an outflow velocity of {approx}3000 km s{sup -1} is implied. These results are discussed in the context of accretion flow in Be-star, neutron star, and black hole X-ray binaries.

  19. X-ray spectroscopy for chemical and energy sciences: the case of heterogeneous catalysis.

    PubMed

    Frenkel, Anatoly I; van Bokhoven, Jeroen A

    2014-09-01

    Heterogeneous catalysis is the enabling technology for much of the current and future processes relevant for energy conversion and chemicals synthesis. The development of new materials and processes is greatly helped by the understanding of the catalytic process at the molecular level on the macro/micro-kinetic time scale and on that of the actual bond breaking and bond making. The performance of heterogeneous catalysts is inherently the average over the ensemble of active sites. Much development aims at unravelling the structure of the active site; however, in general, these methods yield the ensemble-average structure. A benefit of X-ray-based methods is the large penetration depth of the X-rays, enabling in situ and operando measurements. The potential of X-ray absorption and emission spectroscopy methods (XANES, EXAFS, HERFD, RIXS and HEROS) to directly measure the structure of the catalytically active site at the single nanoparticle level using nanometer beams at diffraction-limited storage ring sources is highlighted. The use of pump-probe schemes coupled with single-shot experiments will extend the time range from the micro/macro-kinetic time domain to the time scale of bond breaking and making. PMID:25177997

  20. Measurement of c-axis angular orientation in calcite (CaCO3) nanocrystals using X-ray absorption spectroscopy.

    PubMed

    Gilbert, P U P A; Young, Anthony; Coppersmith, Susan N

    2011-07-12

    We demonstrate that the ability to manipulate the polarization of synchrotron radiation can be exploited to enhance the capabilities of X-ray absorption near-edge structure (XANES) spectroscopy, to include linear dichroism effects. By acquiring spectra at the same photon energies but different polarizations, and using a photoelectron emission spectromicroscope (PEEM), one can quantitatively determine the angular orientation of micro- and nanocrystals with a spatial resolution down to 10 nm. XANES-PEEM instruments are already present at most synchrotrons, hence these methods are readily available. The methods are demonstrated here on geologic calcite (CaCO(3)) and used to investigate the prismatic layer of a mollusk shell, Pinctada fucata. These XANES-PEEM data reveal multiply oriented nanocrystals within calcite prisms, previously thought to be monocrystalline. The subdivision into multiply oriented nanocrystals, spread by more than 50°, may explain the excellent mechanical properties of the prismatic layer, known for decades but never explained. PMID:21693647

  1. Measurement of c-axis angular orientation in calcite (CaCO3) nanocrystals using X-ray absorption spectroscopy

    PubMed Central

    Gilbert, P. U. P. A.; Young, Anthony; Coppersmith, Susan N.

    2011-01-01

    We demonstrate that the ability to manipulate the polarization of synchrotron radiation can be exploited to enhance the capabilities of X-ray absorption near-edge structure (XANES) spectroscopy, to include linear dichroism effects. By acquiring spectra at the same photon energies but different polarizations, and using a photoelectron emission spectromicroscope (PEEM), one can quantitatively determine the angular orientation of micro- and nanocrystals with a spatial resolution down to 10 nm. XANES-PEEM instruments are already present at most synchrotrons, hence these methods are readily available. The methods are demonstrated here on geologic calcite (CaCO3) and used to investigate the prismatic layer of a mollusk shell, Pinctada fucata. These XANES-PEEM data reveal multiply oriented nanocrystals within calcite prisms, previously thought to be monocrystalline. The subdivision into multiply oriented nanocrystals, spread by more than 50°, may explain the excellent mechanical properties of the prismatic layer, known for decades but never explained. PMID:21693647

  2. Ultra-Small-Angle X-ray Scattering – X-ray Photon Correlation Spectroscopy Studies of Incipient Structural Changes in Amorphous Calcium Phosphate Based Dental Composites

    PubMed Central

    Zhang, F.; Allen, A.J.; Levine, L.E.; Espinal, L.; Antonucci, J.M.; Skrtic, D.; O’Donnell, J.N.R.; Ilavsky, J.

    2012-01-01

    The local structural changes in amorphous calcium phosphate (ACP) based dental composites were studied under isothermal conditions using both static, bulk measurement techniques and a recently developed methodology based on combined ultra-small angle X-ray scattering – X-ray photon correlation spectroscopy (USAXS-XPCS), which permits a dynamic approach. While results from conventional bulk measurements do not show clear signs of structural change, USAXS-XPCS results reveal unambiguous evidence for local structural variations on a similar time scale to that of water loss in the ACP fillers. A thermal-expansion based simulation indicates that thermal behavior alone does not account for the observed dynamics. Together, these results suggest that changes in the water content of ACP affect the composite morphology due to changes in ACP structure that occur without an amorphous-to-crystalline conversion. It is also noted that biomedical materials research could benefit greatly from USAXS-XPCS, a dynamic approach. PMID:22374649

  3. ATOMIC AND MOLECULAR PHYSICS: X-ray absorption near the edge structure and X-ray photoelectron spectroscopy studies on pyrite prepared by thermally sulfurizing iron films

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Liu, Ying-Shu; Wang, Bao-Yi; Wei, Long; Kui, Re-Xi; Qian, Hai-Jie

    2009-07-01

    This paper reports how pyrite films were prepared by thermal sulfurization of magnetron sputtered iron films and characterized by x-ray absorption near edge structure spectra and x-ray photoelectron spectroscopy on a 4B9B beam line at the Beijing Synchrotron Radiation Facility. The band gap of the pyrite agrees well with the optical band gap obtained by a spectrophotometer. The octahedral symmetry of pyrite leads to the splitting of the d orbit into t2g and eg levels. The high spin and low spin states were analysed through the difference of electron exchange interaction and the orbital crystal field. Only when the crystal field splitting is higher than 1.5 eV, the two weak peaks above the white lines can appear, and this was approved by experiments in the present work.

  4. Synchrotron soft X-ray absorption spectroscopy study of carbon and silicon nanostructures for energy applications.

    PubMed

    Zhong, Jun; Zhang, Hui; Sun, Xuhui; Lee, Shuit-Tong

    2014-12-10

    Carbon and silicon materials are two of the most important materials involved in the history of the science and technology development. In the last two decades, C and Si nanoscale materials, e.g., carbon nanotubes, graphene, and silicon nanowires, and quantum dots, have also emerged as the most interesting nanomaterials in nanoscience and nanotechnology for their myriad promising applications such as for electronics, sensors, biotechnology, etc. In particular, carbon and silicon nanostructures are being utilized in energy-related applications such as catalysis, batteries, solar cells, etc., with significant advances. Understanding of the nature of surface and electronic structures of nanostructures plays a key role in the development and improvement of energy conversion and storage nanosystems. Synchrotron soft X-ray absorption spectroscopy (XAS) and related techniques, such as X-ray emission spectroscopy (XES) and scanning transmission X-ray microscopy (STXM), show unique capability in revealing the surface and electronic structures of C and Si nanomaterials. In this review, XAS is demonstrated as a powerful technique for probing chemical bonding, the electronic structure, and the surface chemistry of carbon and silicon nanomaterials, which can greatly enhance the fundamental understanding and also applicability of these nanomaterials in energy applications. The focus is on the unique advantages of XAS as a complementary tool to conventional microscopy and spectroscopy for effectively providing chemical and structural information about carbon and silicon nanostructures. The employment of XAS for in situ, real-time study of property evolution of C and Si nanostructures to elucidate the mechanisms in energy conversion or storage processes is also discussed. PMID:25204894

  5. Where Water Is Oxidized to Dioxygen: Structure of the Photosynthetic Mn4Ca Cluster from X-ray Spectroscopy

    PubMed Central

    Yano, Junko; Yachandra, Vittal K.

    2014-01-01

    Light-driven oxidation of water to dioxygen in plants, algae, and cyanobacteria is catalyzed within photosystem II (PS II) by a Mn4Ca cluster. Although the cluster has been studied by many different methods, its structure and mechanism have remained elusive. X-ray absorption and emission spectroscopy and extended X-ray absorption fine structure studies have been particularly useful in probing the electronic and geometric structures and the mechanism of the water oxidation reaction. Recent progress, reviewed here, includes polarized X-ray absorption spectroscopy measurements of PS II single crystals. Analysis of those results has constrained the Mn4Ca cluster geometry to a set of three similar high-resolution structures. The structure of the cluster from the present study is unlike either the 3.0- or 3.5-Å-resolution X-ray structures or other previously proposed models. The differences between the models derived from X-ray spectroscopy and crystallography are predominantly because of damage to the Mn4Ca cluster by X-rays under conditions used for the structure determination by X-ray crystallography. X-ray spectroscopy studies are also used for studying the changes in the structure of the Mn4Ca catalytic center as it cycles through the five intermediate states known as the Si states (i = 0–4). The electronic structure of the Mn4Ca cluster has been studied more recently using resonant inelastic X-ray scattering spectroscopy (RIXS), in addition to the earlier X-ray absorption and emission spectroscopy methods. These studies are revealing that the assignment of formal oxidation states is overly simplistic. A more accurate description should consider the charge density on the Mn atoms, which includes the covalency of the bonds and delocalization of the charge over the cluster. The geometric and electronic structures of the Mn4Ca cluster in the S states derived from X-ray spectroscopy are leading to a detailed understanding of the mechanism of O–O bond formation during the photosynthetic water-splitting process. PMID:18330965

  6. X-ray Spectroscopy of K- and L-shell Z-pinch and Astrophysical Plasmas

    SciTech Connect

    Dasgupta, A.; Davis, J.; Giuliani, J. G. [Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 (United States); Clark, R. W. [Berkeley Research Associates, Beltsville, Maryland 20705 (United States)

    2009-09-10

    In recent years, there have been significant advances in instrumental capabilities for making X-ray spectroscopic measurements of astrophysical plasmas. There have been corresponding improvements in X-ray diagnostics for advanced multi-mega-ampere pulse power machines that produce increasingly large radiative yields from gas-puff and wire array Z pinch plasmas. Analysis used for Z pinches can be used to study ICF and also astrophysical plasmas where laboratory measurements and simulations are the only means to interpret observed data. The astrophysical data for Fe, the most cosmically abundant high Z element, can provide a wealth of information about cosmic plasmas. Fe is also the key element in stainless steel (SS) wire arrays that are investigated as an intense X-ray radiation source at the Z machine at Sandia National Laboratories. The implosion dynamics of an array of wires on the Z and/or refurbished Z accelerator produces an abundance of radiation from the K- and L-shell ionization stages. These dynamic plasmas are inherently non-LTE, with opacity and other factors influencing the X-ray output. As the plasma assembles on axis, a number of time resolved snapshots provide temperature and density profiles and map the emitting region. We will analyze the ionization dynamics and generate K- and L-shell spectra using the conditions generated in the Z and/or refurbished Z accelerator, described by a 1-D non-LTE radiation-hydrodynamics model. Diagnostics based on spectral shape of L-shell emissions are inherently more difficult than those based on K-shell emissions because of more complex multiplet structures and line overlaps. The non-LTE populations are obtained by using detailed atomic models that include all important excitation, ionization, and recombination processes. We will highlight the connection between laboratory Z-pinch plasma simulations and astrophysical plasmas.

  7. Comparison of the accuracies of two methods for the determination of the surface normal for x-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Seah, M. P.

    2007-06-01

    Determining the true angle of detection of emitted electrons is a major factor for the accurate determination of film thicknesses in the range below 10 nm by x-ray photoelectron spectroscopy. To do this, the orientation of the surface normal in the instrument first requires determination. A comparison is made of two recent methods for the definition of the surface normal in x-ray photoelectron spectrometers. The first method, which we call the crystal axis method, involves the measurement of the Si 2p oxide and substrate intensities in the range ±5° around the surface normal for a (1 0 0) Si wafer with approximately 1 nm of thermal oxide. The second method, which we call the overlayer thickness consistency method, involves measuring similar intensities at 10°, 20°, 30° and 40° from the surface normal, for an amorphous oxide on amorphous Si sample, with a view to obtaining a consistent thickness. It is shown that both can readily define the surface normal alignment better than 1° but that the crystal axis method, for similar data quality and numbers of spectra, generates uncertainties a factor of approximately three times better than that of the overlayer consistency method and has fewer bias contributions. Possible improvements in the method are shown to be best by recording more data in the crystal axis method rather than, for example, by changing the materials.

  8. Calorimetric Low-Temperature Detectors for X-Ray Spectroscopy on Trapped Highly-Charged Heavy Ions

    NASA Technical Reports Server (NTRS)

    Kilbourne, Caroline; Kraft-Bermuth, S.; Andrianov, V.; Bleile, A.; Echler, A.; Egelhof, P.; Ilieva, S.; Kilbourne, C.; McCammon, D.

    2012-01-01

    The application of Calorimetric Low-Temperature Detectors (CLTDs) has been proposed at the Heavy-Ion TRAP facility HITRAP which is currently being installed at the Helmholtz Research Center for Heavy Ion Research GSI. This cold ion trap setup will allow the investigation of X-rays from ions practically at rest, for which the excellent energy resolution of CLTDs can be used to its full advantage. However, the relatively low intensities at HITRAP demand larger solid angles and an optimized cryogenic setup. The influence of external magnetic fields has to be taken into account. CLTDs will also be a substantial part of the instrumental equipment at the future Facility for Antiproton and Heavy Ion Research (FAIR), for which a wide variety of high-precision X-ray spectroscopy experiments has been proposed. This contribution will give an overview on the chances and challenges for the application of CLTDs at HITRAP as well as perspectives for future experiments at the FAIR facility.

  9. Hard X-Ray Photoemission Spectroscopy of Quasi-One-Dimensional BaVS3

    NASA Astrophysics Data System (ADS)

    Sato, Hitoshi; Tobimatsu, Komei; Tanaka, Arata; Nakamura, Hiroyuki; Utsumi, Yuki; Mimura, Kojiro; Motonami, Satoru; Shimada, Kenya; Ueda, Shigenori; Kobayashi, Keisuke; Namatame, Hirofumi; Taniguchi, Masaki

    Electronic structure of quasi-one-dimensional BaVS3 with metal-insulator transition at 70 K has been investigated by hard x-ray photoemission spectroscopy (HAXPES). An energy gap of 60 meV across the transition temperature is observed in the HAXPES spectra near the Fermi level. Line widths of the Ba 3d5/2 and S 1s spectra continuously decrease on cooling. The analyses based on the Debye model give the Debye temperature of ?D = 250 ± 50 K, which is consistent with ?D = 200 K derived from the specific heat measurements.

  10. Hydrogenated carbon nanotubes: x-ray absorption spectroscopy and ab initio simulation analysis

    NASA Astrophysics Data System (ADS)

    Brzhezinskaya, M.; Yalovega, G.; Shmatko, V.; Klyushin, A.; Bogoslavskaya, E.; Krestinin, A.; Bashkin, I.

    2013-04-01

    The paper presents the results of investigation of the chemical bond formation in hydrogenated single-walled carbon nanotubes using X-ray absorption spectroscopy. All measurements were performed with the use of synchrotron radiation at BESSY II. The C1s absorption spectra point to formation of covalent chemical bonding between the hydrogen and carbon atoms in H-SWNTs. The investigation of the H-SWNT local structure has been carried out on the basis of the semi-empirical PM6 method (MOPAC 2009) and Finite Difference method. The possibility of H-SWNTs dehydrogenation was also investigated.

  11. FPGA-based compression of streaming x-ray photon correlation spectroscopy data

    SciTech Connect

    Madden, Timothy; Jemian, Peter; Narayanan, Surcsh; Sandy, Alec; Sikorski, Marcin; Sprung, Michael; Weizeorick, John

    2011-08-09

    A data acquisition system to perform real-time background subtraction and lower-level-discrimination-based compression of streaming x-ray photon correlation spectroscopy (XPCS) data from a fast charge-coupled device (CCD) area detector has been built and put into service at the Advanced Photon source (APS) at Argonne National Laboratory. A commercial frame grabber with on-board field-programmable gate array (FPGA) was used in the design, and continuously processes 60 frames per second each consisting of 1,024 x 1,024 pixels with up to 64512 photon hits per frame.

  12. Sulfur Kedge X-ray absorption spectroscopy as an experimental probe for S-nitroso proteins

    Microsoft Academic Search

    Robert K.. Szilagyi; David E. Schwab

    2005-01-01

    X-ray absorption spectroscopy at the sulfur K-edge (2.4–2.6keV) provides a sensitive and specific technique to identify S-nitroso compounds, which have significance in nitric oxide-based cell signaling. Unique spectral features clearly distinguish the S-nitroso-form of a cysteine residue from the sulfhydryl-form or from a methionine thioether. Comparison of the sulfur K-edge spectra of thiolate, thiol, thioether, and S-nitroso thiolate compounds indicates

  13. Composition of RF-sputtered refractory compounds determined by X-ray photoelectron spectroscopy

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.; Brainard, W. A.

    1978-01-01

    RF-sputtered coatings of CrB2, MoSi2, Mo2C, TiC, and MoS2 were examined by X-ray photoelectron spectroscopy (XPS). Data on stoichiometry, impurity content, and chemical bonding were obtained. The influences of sputtering target history, deposition time, RF power level, and substrate bias were studied. Significant deviations from stoichiometry and high oxide levels were related to target outgassing. The effect of substrate bias depended on the particular coating material studied.

  14. Probing QED using microwave and X-ray spectroscopy in hydrogenic ions

    NASA Astrophysics Data System (ADS)

    Dunford, R. W.; Raphaelian, M. L. A.; Berry, H. G.; Dewey, M. S.; Deslattes, R. D.

    1988-04-01

    We discuss the status of measurements of the 2s Lamb shift in singly-ionized helium (He +) and of the 1s Lamb shift in one-electron calcium or titanium ions. The He + Lamb shift experiment, which is being done at Princeton University, utilizes the microwave-resonance method in a beam of metastable He +. The high- Z experiment involves measurement of the 1s-2p transition energies using precision X-ray spectroscopy. This experiment will be carried out at the Argonne tandem-Linac (ATLAS).

  15. X-Ray Absorption Spectroscopy of Cuprous-Thiolate Clusters in Saccharomyces Cerevisiae Metallothionein

    SciTech Connect

    Zhang, L.; Pickering, I.J.; Winge, D.R.; George, G.N.

    2009-05-28

    Copper (Cu) metallothioneins are cuprous-thiolate proteins that contain multimetallic clusters, and are thought to have dual functions of Cu storage and Cu detoxification. We have used a combination of X-ray absorption spectroscopy (XAS) and density-functional theory (DFT) to investigate the nature of Cu binding to Saccharomyces cerevisiae metallothionein. We found that the XAS of metallothionein prepared, containing a full complement of Cu, was quantitatively consistent with the crystal structure, and that reconstitution of the apo-metallothionein with stoichiometric Cu results in the formation of a tetracopper cluster, indicating cooperative binding of the Cu ions by the metallothionein.

  16. X-ray absorption spectroscopy studies of electrochemically deposited thin oxide films.

    SciTech Connect

    Balasubramanian, M.

    1998-06-02

    We have utilized ''in situ'' X-ray Absorption Fine Structure Spectroscopy to investigate the structure and composition of thin oxide films of nickel and iron that have been prepared by electrodeposition on a graphite substrate from aqueous solutions. The films are generally disordered. Structural information has been obtained from the analysis of the data. We also present initial findings on the local structure of heavy metal ions, e.g. Sr and Ce, incorporated into the electrodeposited nickel oxide films. Our results are of importance in a number of technological applications, among them, batteries, fuel cells, electrochromic and ferroelectric materials, corrosion protection, as well as environmental speciation and remediation.

  17. X-ray spectroscopy of laser-heated CF2-foils

    NASA Astrophysics Data System (ADS)

    Geissel, Matthias; Bock, R.; Faenov, Anatoly Y.; Hoffmann, D. H. H.; Pikuz, Tatiana A.; Pirzadeh, P.; Rosmej, Frank B.; Rosmej, O.; Roth, M.; Seelig, Wolfgang; Suess, W.; Tauschwitz, A.

    2001-04-01

    At the Z6 experimental area of the Gsesellshaft fur Schwerionenforschung in Darmstadt experiments with the nhelix laser facility were carried out to determine the plasma parameter sch as temperature, degree of ionization and expansion dynamics for laser heated targets, which are used for the ion beam-plasma-interaction experimental series. Spatially resolved x-ray spectroscopy with spherically bent mica crystals showed well collimated jets of He- and H-like ions emerging out of the front and rear surface of the target with energies in the MeV range.

  18. High-resolution X-ray absorption spectroscopy of iron carbonyl complexes.

    PubMed

    Atkins, Andrew J; Bauer, Matthias; Jacob, Christoph R

    2015-06-01

    We apply high-energy-resolution fluorescence-detected (HERFD) X-ray absorption near-edge spectroscopy (XANES) to study iron carbonyl complexes. Mono-, bi-, and tri-nuclear carbonyl complexes and pure carbonyl complexes as well as carbonyl complexes containing hydrocarbon ligands are considered. The HERFD-XANES spectra reveal multiple pre-edge peaks with individual signatures for each complex, which could not be detected previously with conventional XANES spectroscopy. These peaks are assigned and analysed with the help of TD-DFT calculations. We demonstrate that the pre-edge peaks can be used to distinguish the different types of iron-iron interactions in carbonyl complexes. This opens up new possibilities for applying HERFD-XANES spectroscopy to probe the electronic structure of iron catalysts. PMID:25947206

  19. A miniature metal-ceramic x-ray source for spacecraft instrumentation

    Microsoft Academic Search

    L. N. Koppel; J. R. Marshall

    1998-01-01

    Definitive mineralogical identification of materials with x-ray diffraction and fluorescence on remote planetary probes requires the development of a rugged miniature x-ray source that complies with the mass, power, thermal, and electrical management constraints imposed by space missions. Conventional x-ray tubes are generally fragile, glass-envelope designs with heat-sensitive seals. They are too brittle and bulky for planetary missions, and usually

  20. A miniature metal–ceramic x-ray source for spacecraft instrumentation

    Microsoft Academic Search

    L. N. Koppel; J. R. Marshall

    1998-01-01

    Definitive mineralogical identification of materials with x-ray diffraction and fluorescence on remote planetary probes requires the development of a rugged miniature x-ray source that complies with the mass, power, thermal, and electrical management constraints imposed by space missions. Conventional x-ray tubes are generally fragile, glass-envelope designs with heat-sensitive seals. They are too brittle and bulky for planetary missions, and usually

  1. An X-Ray Fluorescence Spectrometer (XRF-J) Instrument for Geochemical Element Mapping of the Galilean Satellites

    NASA Astrophysics Data System (ADS)

    Galuba, G. G.; Köhler, E.; Fabel, O.; Meyer, M.; Denk, T.; Schmedemann, N.; van Gasselt, S.

    2012-10-01

    In 2012 JUpiter Icy moons Explorer was chosen to be the next large science mission of the European Space Agency. We propose an X-ray fluorescence instrument package (XRF-J) to investigate the composition of non-icy surface materials on jovian moons.

  2. Ultraprecision motion control technique for high-resolution x-ray instrumentation

    SciTech Connect

    Shu, D.; Toellner, T. S.; Alp, E. E.

    2000-07-17

    With the availability of third-generation hard x-ray synchrotron radiation sources, such as the Advanced Photon Source (APS) at Argonne National Laboratory, x-ray inelastic scattering and x-ray nuclear resonant scattering provide powerful means for investigating the vibrational dynamics of a variety of materials and condensed matter systems. Novel high-resolution hard x-ray optics with meV energy resolution requires a compact positioning mechanism with 20--50-nrad angular resolution and stability. In this paper, the authors technical approach to this design challenge is presented. Sensitivity and stability test results are also discussed.

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

    SciTech Connect

    Degueldre, Claude, E-mail: claude.degueldre@psi.ch; 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.

  4. X-ray Absorption Spectroscopy as Tool for the Detection and Identification of Sulfur Compounds in Phototrophic Organisms

    Microsoft Academic Search

    Alexander Prange; Josef Hormes; Hartwig Modrow

    X-ray absorption spectroscopy (XAS) is an in situ technique which combines the advantages of a local probe technique with the high penetration strength inherent to X-rays,\\u000a such as no need for long range order and the ability to obtain information on selected sites of a given sample only. Therefore,\\u000a this technique is applicable to a broad variety of scientific topics,

  5. Shedding new light on historical metal samples using micro-focused synchrotron X-ray fluorescence and spectroscopy

    Microsoft Academic Search

    D. Grolimund; M. Senn; M. Trottmann; M. Janousch; I. Bonhoure; A. M. Scheidegger; M. A. Marcus

    2004-01-01

    Synchrotron-based micro-X-ray fluorescence (micro-XRF) and micro-X-ray absorption spectroscopy (micro-XAS) were used in the present study to obtain spatially resolved micro-scale information on elemental composition, trace element distribution, chemical speciation and oxidation state and\\/or mineral phase distribution within historical iron artefacts dating from the Iron Age to early Medieval Times. Large area two-dimensional trace element distribution maps and oxidation state maps

  6. Spectroscopy of Hard X-Rays (2 15 keV) Generated by Focusing Femtosecond Laser on Metal Targets

    Microsoft Academic Search

    Yasushi Fujimoto; Yoichiro Hironaka; Kazutaka G. Nakamura; Ken-ichi Kondo; Masatake Yoshida; Masayuki Ohtani; Hiroshi Tsunemi

    1999-01-01

    Spectroscopy of hard X-rays generated by focusing a femtosecond laser (42 fs at 780 nm) onto metal targets consisting elements of various atomic number (Z) is carried out in the energy range between 2 and 15 keV using a direct-detection charge-coupled-device camera.Sharp K-shell line emissions are observed for X-rays generated from medium-Z targets (Ti, Fe, Ni, Cu and Zn), which

  7. On PbTiO3-(111)Pt interfacial layers and their x-ray photoelectron spectroscopy signature

    Microsoft Academic Search

    S. Habouti; C.-H. Solterbeck; M. Es-Souni; V. Zaporojtchenko

    2008-01-01

    In this work emphasis is placed on the investigation of interfacial layers between sol-gel processed PbTiO3 (PTO) thin films and (111)Pt terminated silicon substrates. The methods used are x-ray diffraction, x-ray photoelectron spectroscopy (XPS) combined with depth profiling, and atomic force microscopy (AFM). In order to avoid artifacts related to ion bombardment, e.g., reduction of Pb ions and preferential sputtering,

  8. Structural properties of the glass system As-Se-S studied by x-ray absorption spectroscopy

    Microsoft Academic Search

    Jinn-Lung Wang; Jyi-Ching Tsai; Chia-Tung Liu; Ponnusamy Nachimuthu; Ling-Yun Jang; Ru-Gan Liu; Jin-Ming Chen

    2000-01-01

    The structural properties of As-Se-S glass system were investigated by x-ray absorption spectroscopy (XANES and EXAFS) using synchrotron radiation. A preliminary characterization by x-ray powder diffraction, differential scanning calorimetric and thermogravimetric measurements was also carried out. The changes in glass transition temperature (Tg) and glass decomposition temperature (Td) associated with glass compositions indicate that sulfur contributes to the instability of

  9. High resolution spectroscopy of the X-ray emission of GRBs by IMXS-BOSS on the ISS

    Microsoft Academic Search

    L. Piro; L. Colasanti; E. Costa; G. Gandolfi; P. Soffitta; F. Gatti; D. Pergolesi; M. Razeti; R. Vaccarone; G. Testera; M. Pallavicini; A. Ferrari; E. Trussoni; M. Orio; D. McCammon; W. T. Sanders; M. Galeazzi; A. E. Szymkowiak; F. S. Porter; R. Kelley

    2002-01-01

    The IMXS (Interstellar and intergalactic Medium X-ray Survey)-BOSS (gamma-ray Burst Observatory and Spectroscopy Survey) is an experiment proposed to fly on the ISS (International Space Station), in order to perform an all-sky survey to study the diffuse X-ray emission and to measure the spectra of Gamma-Ray Bursts (GRB) with high energy resolution in the 0.1-10 keV energy range. In a

  10. Soft X-ray spectroscopy and quantum chemistry characterization of defects in onion-like carbon produced by nanodiamond annealing

    Microsoft Academic Search

    L. G. Bulusheva; A. V. Okotrub; V. L. Kuznetsov; D. V. Vyalikh

    2007-01-01

    The electronic structure of onion-like carbon (OLC) consisted of quasi-spherical and polyhedral nanoparticles and produced as a result of nanodiamond annealing at 1800 K and 2140 K has been probed by soft X-ray emission and X-ray absorption spectroscopy. The enhanced density of states in the vicinity of the Fermi level was revealed for OLC prepared at moderate temperature. Ab initio calculation on

  11. X-ray absorption spectroscopy on magnetic nanoscale systems for modern applications

    NASA Astrophysics Data System (ADS)

    Schmitz-Antoniak, Carolin

    2015-06-01

    X-ray absorption spectroscopy facilitated by state-of-the-art synchrotron radiation technology is presented as a powerful tool to study nanoscale systems, in particular revealing their static element-specific magnetic and electronic properties on a microscopic level. A survey is given on the properties of nanoparticles, nanocomposites and thin films covering a broad range of possible applications. It ranges from the ageing effects of iron oxide nanoparticles in dispersion for biomedical applications to the characterisation on a microscopic level of nanoscale systems for data storage devices. In this respect, new concepts for electrically addressable magnetic data storage devices are highlighted by characterising the coupling in a BaTiO3/CoFe2O4 nanocomposite as prototypical model system. But classical magnetically addressable devices are also discussed on the basis of tailoring the magnetic properties of self-assembled ensembles of FePt nanoparticles for data storage and the high-moment material Fe/Cr/Gd for write heads. For the latter cases, the importance is emphasised of combining experimental approaches in x-ray absorption spectroscopy with density functional theory to gain a more fundamental understanding.

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

    SciTech Connect

    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.

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

    SciTech Connect

    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.

  14. X-ray emission and photoluminescence spectroscopy of nanostructured silica with implanted copper ions

    NASA Astrophysics Data System (ADS)

    Zatsepin, D. A.; Kortov, V. S.; Kurmaev, É. Z.; Gavrilov, N. V.; Wilks, R. G.; Moewes, A.

    2008-12-01

    Quartz glass samples and compacted SiO2 nanopowders have been studied by x-ray emission (Cu L 2, 3 transition 3 d4 s ? 2 p 1/2, 3/2) and photoluminescence spectroscopy following pulsed Cu+ ion implantation (energy, 30 keV; pulse current up to 0.5 A; pulse duration, 400 ?s; irradiation doses, 1015, 1016, and 2 × 1017 cm-2). It has been established that ion irradiation gives rise to the formation of glassy and compacted SiO2 samples of nanosized metallic and oxide phases in the structure. An analysis of Cu L x-ray emission spectra has shown that copper nanoparticles are thermodynamically metastable and chemically active because ion beam bombardment transfers them readily to the oxide form. This results from the radiation-stimulated fracture of regular Si-O-Si bonds in amorphous SiO2 and the formation of defective Si-Si bonds, followed by capture of oxygen by copper atoms. The enhanced degree of oxidation of copper ions in SiO2 nanostructured pellets can be reduced by coimplantation and thermal annealing. Optical spectroscopy studies suggest that, in glasses and SiO2 nanostructured pellets, there exist metallic Cu{/n 0} nanoclusters, which at low temperatures exhibit quantum-confined photoluminescence with a characteristic stepped excitation spectrum.

  15. High-resolution X-ray emission spectroscopy with transition-edge sensors: present performance and future potential.

    PubMed

    Uhlig, J; Doriese, W B; Fowler, J W; Swetz, D S; Jaye, C; Fischer, D A; Reintsema, C D; Bennett, D A; Vale, L R; Mandal, U; O'Neil, G C; Miaja-Avila, L; Joe, Y I; El Nahhas, A; Fullagar, W; Parnefjord Gustafsson, F; Sundström, V; Kurunthu, D; Hilton, G C; Schmidt, D R; Ullom, J N

    2015-05-01

    X-ray emission spectroscopy (XES) is a powerful element-selective tool to analyze the oxidation states of atoms in complex compounds, determine their electronic configuration, and identify unknown compounds in challenging environments. Until now the low efficiency of wavelength-dispersive X-ray spectrometer technology has limited the use of XES, especially in combination with weaker laboratory X-ray sources. More efficient energy-dispersive detectors have either insufficient energy resolution because of the statistical limits described by Fano or too low counting rates to be of practical use. This paper updates an approach to high-resolution X-ray emission spectroscopy that uses a microcalorimeter detector array of superconducting transition-edge sensors (TESs). TES arrays are discussed and compared with conventional methods, and shown under which circumstances they are superior. It is also shown that a TES array can be integrated into a table-top time-resolved X-ray source and a soft X-ray synchrotron beamline to perform emission spectroscopy with good chemical sensitivity over a very wide range of energies. PMID:25931095

  16. Soft X-Ray Microscopy and Spectroscopy at the Molecular Environmental Science Beamline at the Advanced Light Source

    SciTech Connect

    Bluhm, Hendrik; Andersson, Klas J.; Araki, Tohru; Benzerara, Karim; Brown, Gordon E.; Dynes, Jay J.; Ghosal, Sutapa; Gilles, Mary K.; Hansen, Hans C.; Hemminger, J. C.; Hitchcock, Adam P.; Ketteler, Guido; Kilcoyne, Arthur L.; Kneedler, Eric M.; Lawrence, John R.; Leppard, Gary G.; Majzlam, Juraj; Mun, B. S.; Myneni, Satish C.; Nilsson, Anders R.; Ogasawara, Hirohito; Ogletree, D. F.; Pecher, Klaus H.; Salmeron, Miquel B.; Shuh, David K.; Tonner, Brian; Tyliszczak, Tolek; Warwick, Tony; Yoon, T. H.

    2006-02-01

    We present examples of the application of synchrotron-based spectroscopies and microscopies to environmentally-relevant samples. The experiments were performed at the Molecular Environmental Science beamline (11.0.2) at the Advanced Light Source, Lawrence Berkeley National Laboratory. Examples range from the study of water monolayers on Pt(111) single crystal surfaces using X-ray emission spectroscopy and the examination of alkali halide solution/water vapor interfaces using ambient pressure photoemission spectroscopy, to the investigation of actinides, river-water biofilms, Al-containing colloids and mineral-bacteria suspensions using scanning transmission X-ray spectromicroscopy. The results of our experiments show that spectroscopy and microscopy in the soft X-ray energy range are excellent tools for the investigation of environmentally relevant samples under realistic conditions, i.e. with water or water vapor present at ambient temperature.

  17. fSurface analysis with XRay Photoelectron SpectroscopyX Ray Photoelectron Spectroscopy

    E-print Network

    Shoubridge, Eric

    X-rays are generated? Sometimes there is a monochromator before the sample Ultra high vacuum!U a g Analysis chamber (ultra high vacuum) Transfer arm Load lock Transfer arm (high vacuum)(high vacuum) #12 of energies #12;Detector V Avalanche effect: gains of 107-108 electrons #12;XPS spectrum of chromate coating

  18. Silicon drift detectors with on-chip electronics for x-ray spectroscopy.

    PubMed

    Fiorini, C; Longoni, A; Hartmann, R; Lechner, P; Strüder, L

    1997-01-01

    The silicon drift detector (SDD) is a semiconductor device based on high resistivity silicon fully depleted through junctions implanted on both sides of the semiconductor wafer. The electrons generated by the ionizing radiation are driven by means of a suitable electric field from the point of interaction toward a collecting anode of small capacitance, independent of the active area of the detector. A suitably designed front-end JFET has been directly integrated on the detector chip close to the anode region, in order to obtain a nearly ideal capacitive matching between detector and transistor and to minimize the stray capacitances of the connections. This feature allows it to reach high energy resolution also at high count rates and near room temperature. The present work describes the structure and the performance of SDDs specially designed for high resolution spectroscopy with soft x rays at high detection rate. Experimental results of SDDs used in spectroscopy applications are also reported. PMID:21307544

  19. Uses of Auger and x ray photoelectron spectroscopy in the study of adhesion and friction

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1990-01-01

    Three studies are described characterizing the possible contributions of surface science to tribology. These include surface contamination formed by the interaction of a surface with the environment, contaminants obtained with diffusion of compounds, and surface chemical changes resulting from selective thermal evaporation. Surface analytical tools such as Auger electron spectroscopy (AES) and x ray photoelectron spectroscopy (XPS) incorporated directly into adhesion and friction systems are primarily used to define the nature of tribological surfaces before and after tribological experimentation and to characterize the mechanism of solid-to-solid interaction. Emphasis is on fundamental studies involving the role of surfaces in controlling the adhesion and friction properties of materials emerging as a result of the surface analyses. The materials which were studied include metals and ceramics such as elemental metals, amorphous alloys (metallic glasses), and silicon-based ceramics.

  20. A Laboratory Scale Critical-Dimension Small-Angle X-ray Scattering Instrument

    Microsoft Academic Search

    Derek L. Ho; Chengqing Wang; Eric K. Lin; Ronald L. Jones; Wen-Li Wu

    2007-01-01

    New methods for critical dimension (CD) measurements may be needed to enable the detailed characterization of nanoscale structures produced in the semiconductor industry and for nanotechnology applications. In earlier work, small angle x-ray scattering (SAXS) measurements with synchrotron sources have shown promise in meeting several grand challenges for CD metrology. However, it is not practical to depend upon x-ray synchrotron

  1. X-ray absorption spectroscopy: A fluorescence detection system based on a plastic scintillator

    NASA Astrophysics Data System (ADS)

    Tourillon, G.; Guay, D.; Lemonnier, M.; Bartol, F.; Badeyan, M.

    1990-09-01

    A fluorescence detection system based on a plastic scintillator is presented that can be used for both X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Its counting rate is limited by the pulsation frequency of the synchrotron radiation (3.16×10 6 counts s -1), and can be theoretically extended to roughly 5×10 7 counts s -1 if used on a multibunch storage ring synchrotron radiation source. Its physical characteristics (fluorescence decay time and fast electronics) are such that the dead-time correction is entirely defined by the revolution period of the charged particles in the storage ring. It shows a broad spectral response and is particularly well adapted to the measurement of hard X-rays (from 6 to 25 keV). Its volume is small (diameter 60 mm; height 240 mm), and filters of small dimensions are used to preferentially remove the scattered radiation. The entrance window of the detector is placed at 2-3 mm above the top of the sample, and a solid angle of collection of nearly 50% of 2? sr is achieved. The shape of the plastic scintillator can be easily modified to fit various geometries. It operates in both horizontal and vertical planes. It is about ten times less expensive than an energy-dispersive detection system based on a single Ge solid-state detector. The detector presents a high sensitivity. It is possible to obtain the entire EXAFS spectrum of an electrochemically (under potential deposition) deposited monolayer of Cu atoms on gold, with acquisition time of less than one hour (compared to 25 h for a Ge solid-state detector). Orientation-dependent X-ray absorption spectroscopy was performed on thin (800 Å) copper phthalocyanine film, and the spectra of diluted Cu 2+ ions in aqueous solution (18 ppm) and Co atoms in YBa 2Cu 3O 7 powder (230 ppm) were also measured to assess the sensitivity of the detector.

  2. Electronic structure measurements of metal-organic solar cell dyes using x-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Johnson, Phillip S.

    The focus of this thesis is twofold: to report the results of X-ray absorption studies of metal-organic dye molecules for dye-sensitized solar cells and to provide a basic training manual on X-ray absorption spectroscopy techniques and data analysis. The purpose of our research on solar cell dyes is to work toward an understanding of the factors influencing the electronic structure of the dye: the choice of the metal, its oxidation state, ligands, and cage structure. First we study the effect of replacing Ru in several common dye structures by Fe. First-principles calculations and X-ray absorption spectroscopy at the C 1s and N 1s edges are combined to investigate transition metal dyes in octahedral and square planar N cages. Octahedral molecules are found to have a downward shift in the N 1s-to-pi* transition energy and an upward shift in C 1s-to-pi* transition energy when Ru is replaced by Fe, explained by an extra transfer of negative charge from Fe to the N ligands compared to Ru. For the square planar molecules, the behavior is more complex because of the influence of axial ligands and oxidation state. Next the crystal field parameters for a series of phthalocyanine and porphyrins dyes are systematically determined using density functional calculations and atomic multiplet calculations with polarization-dependent X-ray absorption spectra. The polarization dependence of the spectra provides information on orbital symmetries which ensures the determination of the crystal field parameters is unique. A uniform downward scaling of the calculated crystal field parameters by 5-30% is found to be necessary to best fit the spectra. This work is a part of the ongoing effort to design and test new solar cell dyes. Replacing the rare metal Ru with abundant metals like Fe would be a significant advance for dye-sensitized solar cells. Understanding the effects of changing the metal centers in these dyes in terms of optical absorption, charge transfer, and electronic structure enables the systematic design of new dyes using less expensive materials.

  3. Surface spectroscopic study of tungsten-alumina catalysts using x-ray photoelectron, ion scattering, and Raman spectroscopies

    Microsoft Academic Search

    Lawrence Salvati; Leo E. Makovsky; J. M. Stencel; F. R. Brown; David M. Hercules

    1981-01-01

    X-ray photoelectron spectroscopy (XPS) (= electron spectroscopy for chemical analysis (ESCA)), ion scattering spectroscopy (ISS), and laser Raman spectroscopy (LRS) have been used to characterize a series of WOâ\\/AlâOâ (TA) catalysts. The results of this investigation show that WOâ\\/AlâOâ catalysts are structurally similar to MoOâ\\/AlâOâ catalysts. Three distinctly different tungsten species were identified by using LRS. At low WOâ loadings

  4. Planetary and satellite x ray spectroscopy: A new window on solid-body composition by remote sensing

    NASA Technical Reports Server (NTRS)

    Chenette, D. L.; Wolcott, R. W.; Selesnick, R. S.

    1993-01-01

    The rings and most of the satellites of the outer planets orbit within the radiation belts of their parent bodies. This is an environment with intense fluxes of energetic electrons. As a result, these objects are strong emitters of X-rays. The characteristic X-ray lines from these bodies depend on atomic composition, but they are not sensitive to how the material is arranged in compounds or mixtures. X-ray fluorescence spectral analysis has demonstrated its unique value in the laboratory as a qualitative and quantitative analysis tool. This technique has yet to be fully exploited in a planetary instrument for remote sensing. The characteristic X-ray emissions provide atomic relative abundances. These results are complementary to the molecular composition information obtained from IR, visible, and UV emission spectra. The atomic relative abundances are crucial to understanding the formation and evolution of these bodies. They are also crucial to the proper interpretation of the molecular composition results from the other sensors. The intensities of the characteristic X-ray emissions are sufficiently strong to be measured with an instrument of modest size. Recent developments in X-ray detector technologies and electronic miniaturization have made possible space-flight X-ray imaging and nonimaging spectrometers of high sensitivity and excellent energy resolution that are rugged enough to survive long-duration space missions. Depending on the application, such instruments are capable of resolving elemental abundances of elements from carbon through iron. At the same time, by measuring the bremsstrahlung intensity and energy spectrum, the characteristics of the source electron flux can be determined. We will discuss these concepts, including estimated source strengths, and will describe a small instrument capable of providing this unique channel of information for future planetary missions. We propose to build this instrument using innovative electronics packaging methods to minimize size and weight.

  5. Characterization of silicon-oxynitride dielectric thin films using grazing incidence x-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Landree, Eric; Jach, Terrence; Brady, David; Karamcheti, Arun; Canterbury, Jesse; Chism, Will; Diebold, Alain C.

    2001-01-01

    To achieve the future goals for logic device dielectric film thickness and composition metrology, a set of well-characterized calibration reference material standards are needed for validating real-time diagnostic techniques used during production. However, there are only a finite number of techniques capable of providing the desired information within this thickness range. Furthermore, the techniques available can disagree on the absolute measured film thickness by an amount that is greater than their respective measurement uncertainty. It is evident that more information is needed to establish a measurement technique capable of satisfying this requirement for the ULSI semiconductor manufacturing industry. A promising technique for characterizing ultrathin films is grazing incidence x-ray photoelectron spectroscopy (GIXPS). GIXPS utilizes the dependence on the material properties of the film, along with the incident angle of the x-rays to control the electric field penetration into the sample. By varying the angle of incidence from zero to some value slightly greater than the angle for total x-ray external reflection, it is possible to nondestructively probe the nature of the film depth profile. The desired physical properties, such as film profile, density and thickness, are extracted by constructing a model of the film structure and comparing the measured angle-dependent photoemission spectrum to the calculated spectrum. The measured dielectric thin film thickness and the film depth profile from a diverse group of silicon oxynitride samples in the range of 2 nm to 5 nm will be discussed. In addition, challenges associated with the dependence of the technique upon various fundamental materials parameters will be addressed.

  6. A unique 30 Tesla single-solenoid pulsed magnet instrument for x-ray studies

    NASA Astrophysics Data System (ADS)

    Islam, Zahirul; Capatina, Dana; Ruff, Jacob; Das, Ritesh; Nojiri, Hiroyuki; Narumi, Yasuo

    2011-03-01

    We present a dual-cryostat pulsed-magnet instrument at the Advanced Photon Source (APS) with unique capabilities. The dual-cryostat independently cools the solenoid (Tohoku design) using liquid nitrogen and the sample using a closed-cycle refrigerator, respectively. Liquid nitrogen (LN) cooling allows a repetition rate of seven minutes for peak fields of 30 Tesla. The system is unique in that the LN cryostat incorporates a double-funnel vacuum tube passing through the solenoid's bore preserving the entire angular range allowed by the magnet. This scheme is advantageous in that it allows the applied magnetic field to be parallel to the scattering plane complementing typical split-pair magnets with fields normal to the scattering plane. Performance of the coils along with preliminary x-ray diffraction and spectroscopic studies will be presented. Use of the APS is supported by the U. S. DOE, Office of Science, under Contract No. DE-AC02-06CH11357. The work was supported in part by ICC-IMR, Tohoku University.

  7. Advances in Time Resolved X-ray Excited Optical Luminescence Instrumentation at the Canadian Light Source

    SciTech Connect

    Regier, T. Z.; Vogt, J. M. [Canadian Light Source, Inc., 101 Perimeter Road, Saskatoon, Saskatchewan (Canada); Sammynaiken, R. [Sasakatchewan Structural Science Centre, 110 Science Place, Saskatoon, Saskatchewan (Canada); Sham, T. K. [Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario (Canada)

    2010-06-23

    Measurement of the optical emission properties of samples excited by x-rays can be used to study defect states in crystals and the optical properties of nanostructured materials. Changes in the intensities, wavelengths and lifetimes of the optical emission can occur when specific core level electrons are excited using tuneable light from a synchrotron light source. At the Canadian Light Source (CLS), collaboration between the user community, the experimental facilities group and the accelerator division has resulted in improved capabilities in the acquisition of Time Resolved XEOL (TRXEOL) data. Using a streak camera, the optical luminescence decay curves from samples excited with 35 ps long synchrotron pulses have been obtained. The streak tube is operated in single sweep mode and is triggered by the 500 MHz RF signal, which has been resynchronized to the orbit clock frequency giving a highly stable trigger pulse. A transverse kicker system is used to improve bunch purity from 10{sup 2} to 10{sup 6}. The decay curves of the XEOL of nanostructured ZnO and a high pressure form of SiO{sub 2} have been measured and demonstrate the unique capabilities of this instrumentation.

  8. Evaluation of high-resolution X-ray absorption and emission spectroscopy for the chemical speciation of binary titanium compounds.

    PubMed

    Reinhardt, F; Beckhoff, B; Eba, H; Kanngiesser, B; Kolbe, M; Mizusawa, M; Müller, M; Pollakowski, B; Sakurai, K; Ulm, G

    2009-03-01

    For the chemical speciation of binary compounds of tri- and tetravalent titanium, high-resolution X-ray absorption and emission spectra were recorded in different energy regimes in order to evaluate and to qualify both near-edge X-ray absorption fine structure (NEXAFS or XANES) spectroscopy and wavelength-dispersive X-ray emission spectroscopy (WDXES) as spectroscopic methods for this analytical task. A high resolving power in the excitation channel was ensured by use of monochromatic synchrotron radiation provided by BESSY II, where the soft X-ray emission spectra were recorded as well. In the hard X-ray range, emission measurements were performed at SPring-8. For a comparison of the information gained from the various methods, the titanium compounds were classified according to the bonded titanium's oxidation state. Thus, it was possible to distinguish between inner atomic effects due to different oxidation states and external effects related to the respective ligand and the surrounding structure. It becomes evident, that certain compounds, while hardly distinguishable in their Ti-K XANES spectra, still show significant differences in their emission characteristics. On the other hand, some compounds with little difference in their emission spectra are easily distinguished by their NEXAFS structures. Only the combined use of the complementary methods both in the soft and the hard X-ray range allows for a reliable speciation of tri- and tetravalent titanium compounds. PMID:19203285

  9. A New Route to Phase-Resolved Spectroscopy of Pulsations and QPOs in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Stevens, A.; Uttley, P.; van der Klis, M.

    2014-07-01

    The accretion disks in neutron star and stellar-mass black hole X-ray binaries provide an opportunity to study matter in strong gravitational fields. In particular, using spectral-timing measurements of X-ray emission, we can analyze the inner parts of the accretion disk and corona. Here we present the application of a new spectral-timing technique to carry out phase-resolved spectroscopy of rapid periodic and quasi-periodic signals from X-ray binaries. This technique measures relative phase and does not require ephemerides or exactly periodic signals, so it is applicable to a wide range of data, from X-ray millisecond pulsations to kHz and low-frequency QPOs. The method gives new insight into the physical mechanisms underlying these signals as well as the geometry of the emitting regions.

  10. Soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy below 100?eV: probing first-row transition-metal M-edges in chemical complexes

    PubMed Central

    Wang, Hongxin; Young, Anthony T.; Guo, Jinghua; Cramer, Stephen P.; Friedrich, Stephan; Braun, Artur; Gu, Weiwei

    2013-01-01

    X-ray absorption and scattering spectroscopies involving the 3d transition-metal K- and L-edges have a long history in studying inorganic and bioinorganic molecules. However, there have been very few studies using the M-edges, which are below 100?eV. Synchrotron-based X-ray sources can have higher energy resolution at M-edges. M-edge X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) could therefore provide complementary information to K- and L-edge spectroscopies. In this study, M 2,3-edge XAS on several Co, Ni and Cu complexes are measured and their spectral information, such as chemical shifts and covalency effects, are analyzed and discussed. In addition, M 2,3-edge RIXS on NiO, NiF2 and two other covalent complexes have been performed and different d–d transition patterns have been observed. Although still preliminary, this work on 3d metal complexes demonstrates the potential to use M-edge XAS and RIXS on more complicated 3d metal complexes in the future. The potential for using high-sensitivity and high-resolution superconducting tunnel junction X-ray detectors below 100?eV is also illustrated and discussed. PMID:23765304

  11. A miniature metal-ceramic x-ray source for spacecraft instrumentation.

    PubMed

    Koppel, L N; Marshall, J R

    1998-04-01

    Definitive mineralogical identification of materials with x-ray diffraction and fluorescence on remote planetary probes requires the development of a rugged miniature x-ray source that complies with the mass, power, thermal, and electrical management constraints imposed by space missions. Conventional x-ray tubes are generally fragile, glass-envelope designs with heat-sensitive seals. They are too brittle and bulky for planetary missions, and usually require cumbersome and power-consuming cooling systems. Here we describe the development of a novel, rugged miniature x-ray source employing a ceramic BeO substrate upon which a metal target material is deposited. Conventional thermionic emission and high-voltage acceleration of electrons to strike the metal target material produce an x-ray yield comparable to conventional x-ray tubes. Thermal management of the x-ray source is achieved with the excellent heat transport properties of the BeO target substrate coupled with a passive heatpipe. PMID:11542818

  12. Chemical Composition and Sulfur Speciation in Bulk Tissue by X-Ray Spectroscopy and X-Ray Microscopy: Corneal Development during Embryogenesis

    PubMed Central

    Koudouna, Elena; Veronesi, Giulia; Patel, Imran I.; Cotte, Marine; Knupp, Carlo; Martin, Francis L.; Quantock, Andrew J.

    2012-01-01

    The chemical composition and sulfur (S) speciation of developing chick corneas at embryonic days 12, 14, and 16 were investigated using synchrotron scanning x-ray fluorescence microscopy and x-ray absorption near-edge structure spectroscopy. The aim was to develop techniques for the analysis of bulk tissue and identify critical physicochemical variations that correlate with changes in corneal structure-function relationships. Derived data were subjected to principal component analysis and linear discriminant analysis, which highlighted differences in the elemental and S species composition at different stages of embryonic growth. Notably, distinct elemental compositions of chlorine, potassium, calcium, phosphorus, and S altered with development during the transition of the immature opaque cornea to a mature transparent tissue. S  structure spectroscopy revealed developmentally regulated alterations in thiols, organic monosulfides, ester sulfate, and inorganic sulfate species. The transient molecular structures and compositional changes reported here provide a deeper understanding of the underlying basis of corneal development during the acquisition of transparency. The experimental and analytical approach is new, to our knowledge, and has wide potential applicability in the life sciences. PMID:22853914

  13. X-ray emission spectroscopy of bulk liquid water in "no-man's land".

    PubMed

    Sellberg, Jonas A; McQueen, Trevor A; Laksmono, Hartawan; Schreck, Simon; Beye, Martin; DePonte, Daniel P; Kennedy, Brian; Nordlund, Dennis; Sierra, Raymond G; Schlesinger, Daniel; Tokushima, Takashi; Zhovtobriukh, Iurii; Eckert, Sebastian; Segtnan, Vegard H; Ogasawara, Hirohito; Kubicek, Katharina; Techert, Simone; Bergmann, Uwe; Dakovski, Georgi L; Schlotter, William F; Harada, Yoshihisa; Bogan, Michael J; Wernet, Philippe; Föhlisch, Alexander; Pettersson, Lars G M; Nilsson, Anders

    2015-01-28

    The structure of bulk liquid water was recently probed by x-ray scattering below the temperature limit of homogeneous nucleation (TH) of ?232 K [J. A. Sellberg et al., Nature 510, 381-384 (2014)]. Here, we utilize a similar approach to study the structure of bulk liquid water below TH using oxygen K-edge x-ray emission spectroscopy (XES). Based on previous XES experiments [T. Tokushima et al., Chem. Phys. Lett. 460, 387-400 (2008)] at higher temperatures, we expected the ratio of the 1b1' and 1b1? peaks associated with the lone-pair orbital in water to change strongly upon deep supercooling as the coordination of the hydrogen (H-) bonds becomes tetrahedral. In contrast, we observed only minor changes in the lone-pair spectral region, challenging an interpretation in terms of two interconverting species. A number of alternative hypotheses to explain the results are put forward and discussed. Although the spectra can be explained by various contributions from these hypotheses, we here emphasize the interpretation that the line shape of each component changes dramatically when approaching lower temperatures, where, in particular, the peak assigned to the proposed disordered component would become more symmetrical as vibrational interference becomes more important. PMID:25637993

  14. X-ray emission spectroscopy of bulk liquid water in "no-man's land"

    NASA Astrophysics Data System (ADS)

    Sellberg, Jonas A.; McQueen, Trevor A.; Laksmono, Hartawan; Schreck, Simon; Beye, Martin; DePonte, Daniel P.; Kennedy, Brian; Nordlund, Dennis; Sierra, Raymond G.; Schlesinger, Daniel; Tokushima, Takashi; Zhovtobriukh, Iurii; Eckert, Sebastian; Segtnan, Vegard H.; Ogasawara, Hirohito; Kubicek, Katharina; Techert, Simone; Bergmann, Uwe; Dakovski, Georgi L.; Schlotter, William F.; Harada, Yoshihisa; Bogan, Michael J.; Wernet, Philippe; Föhlisch, Alexander; Pettersson, Lars G. M.; Nilsson, Anders

    2015-01-01

    The structure of bulk liquid water was recently probed by x-ray scattering below the temperature limit of homogeneous nucleation (TH) of ˜232 K [J. A. Sellberg et al., Nature 510, 381-384 (2014)]. Here, we utilize a similar approach to study the structure of bulk liquid water below TH using oxygen K-edge x-ray emission spectroscopy (XES). Based on previous XES experiments [T. Tokushima et al., Chem. Phys. Lett. 460, 387-400 (2008)] at higher temperatures, we expected the ratio of the 1b1' and 1b1? peaks associated with the lone-pair orbital in water to change strongly upon deep supercooling as the coordination of the hydrogen (H-) bonds becomes tetrahedral. In contrast, we observed only minor changes in the lone-pair spectral region, challenging an interpretation in terms of two interconverting species. A number of alternative hypotheses to explain the results are put forward and discussed. Although the spectra can be explained by various contributions from these hypotheses, we here emphasize the interpretation that the line shape of each component changes dramatically when approaching lower temperatures, where, in particular, the peak assigned to the proposed disordered component would become more symmetrical as vibrational interference becomes more important.

  15. X-ray absorption spectroscopy as a probe of dissolved polysulfides in lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Pascal, Tod; Prendergast, David

    2015-03-01

    There has been enormous interest lately in lithium sulfur batteries, since they have 5 times the theoretical capacity of lithium ion batteries. Large-scale adoption of this technology has been hampered by numerous shortcomings, chiefly the poor utilization of the active cathode material and rapid capacity fading during cycling. Overcoming these limitations requires methods capable of identifying and quantifying the products of the poorly understood electrochemical reactions. One recent advance has been the use of X-ray absorption spectroscopy (XAS), an element-specific probe of the unoccupied energy levels around an excited atom upon absorption of an X-ray photon, to identify the reaction products and intermediates. In this talk, we'll present first principles molecular dynamics and spectral simulations of dissolved lithium polysulfide species, showing how finite temperature dynamics, molecular geometry, molecular charge state and solvent environment conspire to determine the peak positions and intensity of the XAS. We'll present a spectral analysis of the radical (-1e charge) species, and reveal a unique low energy feature that can be used to identify these species from their more common dianion (-2e charge) counterparts.

  16. Gate oxide process control optimization by x-ray photoelectron spectroscopy in a semiconductor fabrication line

    SciTech Connect

    Le Gouil, A.; Cabuil, N.; Dupeyrat, P.; Dickson, B.; Kwan, M.; Barge, D.; Gurer, E.; Doclot, O.; Royer, J.-C. [STMicroelectronics, Metrology, 850 rue J. Monnet, 38926 Crolles Cedex (France); Revera, Incorporated, 810 Kifer Road, Sunnyvale, California 94086 (United States); STMicroelectronics, Metrology, 850 rue J. Monnet, 38926 Crolles Cedex (France); Revera, Incorporated, 810 Kifer Road, Sunnyvale, California 94086 (United States); STMicroelectronics, Metrology, 850 rue J. Monnet, 38926 Crolles Cedex (France); CEA/LETI-Minatec, 17 rue des Martyrs, 38000 Grenoble (France)

    2008-07-15

    X-ray photoelectron spectroscopy is a metrology technique that is used for in-line control of decoupled plasma nitridation processes in the fabrication of logic devices. This article shows XPS results of thickness and composition obtained on two types of gate oxide nitrided by a decoupled plasma nitridation process. Measurements are performed in specific test structures with an x-ray spot which can be focused down to 35 {mu}m, enabling process control directly on products. First, XPS is used to characterize and quantify the chemical composition of a SiON layer. The Results show that the nitrogen composition in a SiON layer decreases at a fast rate during the initial days after nitridation processing and stabilizes with time. Second, measurements are performed on products with the objective of transferring process control from monitor to product wafers. In this regard, comparison of nitrogen dose and thickness uniformity on monitor and pattern wafers show similar trends, indicating that measurements of nitrogen dose and thickness on monitor and product wafers give the same information. Third, different mapping protocols are studied on products to identify the best compromise between throughput and an optimized mapping representative of the process distribution. An optimized process control strategy of gate oxides with results is discussed in this article.

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

    SciTech Connect

    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.

  18. A high pressure x-ray photoelectron spectroscopy study of CO oxidation over Rh(100).

    PubMed

    Gustafson, J; Blomberg, S; Martin, N M; Fernandes, V; Borg, A; Liu, Z; Chang, R; Lundgren, E

    2014-02-01

    We have studied the oxidation of CO over Rh(100) using high pressure x-ray photoelectron spectroscopy under CO and O2 pressures ranging from 0.01 to 1 mbar. The results show a very low or no conversion for the CO covered surface found at low temperatures, while the activity rises slightly when the temperature is high enough for some CO to desorb, exposing surface sites for dissociative O2 adsorption. As the temperature is increased further, more CO desorbs and oxygen replaces CO as the dominating species at the surface. At the same time we find a sudden increase in the reactivity, such that all CO that reaches the surface is instantly transformed into CO2. We find that the O coverage in the active state is highly dependent on the total pressure and, although we do not detect any presence of a surface oxide as in previous surface x-ray diffraction studies, the highest O coverage indicates that the surface is close to being oxidized. PMID:24334623

  19. Site of Mn in Mn {delta}-doped GaAs: X-ray absorption spectroscopy

    SciTech Connect

    D'Acapito, F.; Smolentsev, G.; Boscherini, F.; Piccin, M.; Bais, G.; Rubini, S.; Martelli, F.; Franciosi, A. [CNR-INFM-OGG, c/o ESRF, GILDA CRG, 6 Rue Jules Horowitz, F-38043 Grenoble (France); Department of Physics, Rostov State University, B. Sadovaya 105, 344006 Rostov-na-Donu (Russian Federation); Department of Physics and CNISM, University of Bologna, Viale Berti Pichat 6/2, I-40127 Bologna (Italy); Laboratorio Nazionale TASC INFM-CNR in Area Science Park, S.S. 14, Km 163.5, I-34012 Basovizza, Trieste (Italy)

    2006-01-15

    In order to determine the local structure of Mn in {delta}-doped GaAs layers we have carried out an x-ray absorption spectroscopy experiment at the Mn-K edge in samples grown by molecular beam epitaxy with and without Be co-doping. Mn-Mn atomic correlations have not been found within {approx}5 A radius, ruling out the presence of metallic clusters or local Mn enrichment. In samples deposited at 300 deg. C, Mn substitutionally occupies the Ga site with a local expansion ({approx_equal}2%) of the first-neighbor distance with respect to GaAs; the second neighbors remain at a distance very close to that of the host lattice, indicating that the structural perturbation induced by Mn is very localized. Ab initio simulation of the x-ray absorption near edge structure spectra confirmed that Mn enters the Ga, rather than the As, site. Samples grown at 450 deg. C exhibit a reduction of the first shell coordination number, suggesting the initial phases of MnAs precipitation. In the case of Be co-doping the downward shift of the Fermi energy leads to the appearance of Mn in tetrahedral interstitial sites, of which we provide a previously unavailable local structural description.

  20. X-ray absorption spectroscopy of lithium sulfur battery reaction intermediates

    NASA Astrophysics Data System (ADS)

    Wujcik, Kevin; Pascal, Tod; Prendergast, David; Balsara, Nitash

    2015-03-01

    Lithium sulfur batteries have a theoretical energy density nearly five times greater than current lithium ion battery standards, but questions still remain regarding the reaction pathways through which soluble lithium polysulfide (Li2Sx, ``x'' ranging from 2 to 8) reaction intermediates are formed. Complicating spectroelectrochemical approaches to elucidate redox pathways is the challenge of obtaining spectral standards for individual Li2Sx species. Lithium polysulfides cannot be isolated as individual component and exist only in solution as a distribution of different Li2Sx molecules formed via disproportionation reactions (e.g. 2Li2S4 goes to Li2S3 + Li2S5). X-ray absorption spectroscopy (XAS) at the sulfur K-edge has recently been employed as a technique to study Li-S chemistry. We have recently obtained XAS standards for individual Li2Sx species via first principles DFT simulations and the excited electron and core hole approach. Here, experimental sulfur K-edge XAS of Li2Sx species dissolved in poly(ethylene oxide) are compared to spectra obtained from analogous theoretical calculations. The impact that polysulfide solution concentration and the presence of other lithium salts (e.g. LiNO3) have on X-ray spectra of Li2Sx species is explored via experiment and theory.

  1. The high-throughput X-ray Spectroscopy Mission. Report of the Telescope Working Group.

    NASA Astrophysics Data System (ADS)

    Aschenbach, B.; Citterio, O.; Ellwood, J. M.; Jensen, P.; de Korte, P.; Peacock, A.; Willingale, R.; Burke, W. R.

    This document contains a full discussion of the available optical designs and manufacturing technologies which could be used for the mirror systemin ESA's Cornerstone X-ray Spectroscopy Mission (XMM). The telescope is required to have a full imaging capability, a good energy response and a very large collecting area compared with those of previously flown imaging X-ray telescopes. Three grazing-incidence optical configurations - Wolter Type I, a conical approximation to Wolter Type I and Kirkpatrick-Baez - are considered appropriate and a detailed design study of all three was carried out by ray tracing. The results of this analysis are presented and an optimum design described for each case. TheGroup reviewed currently available production technologies which could be used in the manufacture of the mirrors, highlighting the areas where further development is needed. A complete trade-off analysis, including the optical design, payload interface and production technologies, was performed. The results of this trade-off are presented and a single optical design and manufacturing technique are recommended to meet the performance requirements.

  2. Mossbauer spectroscopy and X-ray diffraction of samples from the Santa Catharina iron meteorite

    NASA Technical Reports Server (NTRS)

    Roy-Poulsen, H.; Clarke, R. S., Jr.; Jensen, G. B.; Knudsen, J. M.; Larsen, L.; Roy-Poulsen, N. O.; Vistisen, L.

    1984-01-01

    Conversion electron Mossbauer spectroscopy (CEMS) of samples from the Santa Catharina iron meteorite shows the presence of the ordered iron-nickel phase with 50% Ni, tetrataenite, and of the paramagnetic iron-nickel phase with 25% Ni. The FeNi phase with 50% Ni amounts to 70% of the iron-nickel alloys. Futhermore, the CEM spectra show the presence of small peaks from one or more spinel compounds. These small peaks are more pronounced when regions near the rim of the samples are analyzed. The X-ray diffraction of different areas of the samples, both optically dark and optically light areas, shows the presence of a diffraction pattern from a single f.c.c. lattice with a lattice parameter of a=3.58A This means that the two different Fe-Ni phases seen in the CEMS analysis occupy the same lattice. The X-ray photographs also show the presence of super-structure reflections from the ordered FeNi phase, and that the orientation of the f.c.c. lattice is the same within the whole sample.

  3. X-ray photoelectron spectroscopy for characterization of bionanocomposite functional materials for energy-harvesting technologies.

    PubMed

    Artyushkova, Kateryna; Atanassov, Plamen

    2013-07-22

    The analysis of hybrid multicomponent bioorganic and bioinorganic composite materials related to energy technologies by using X-ray photoelectron spectroscopy is discussed. The approaches and considerations of overcoming the difficulties of analyzing hybrid multicomponent materials are demonstrated for different types of materials used in bioenzyme fuel cells, that is, enzyme immobilization in a hybrid inorganic-organic matrix, analysis of peptide binding and structure in the mediation of silica nanoparticle formation, analysis of enzyme-polymeric multilayered architectures obtained through layer-by-layer assembly, and study of the mechanism of electropolymerization. Thorough optimization of experimental design through analysis of an adequate set of reference materials, relevant timescales of sample preparation and X-ray exposure, careful peak decomposition and cross-correlation between elemental speciation, results in a detailed understanding of the chemistry of nanocomposite constituents and interactions between them. The methodology presented and examples discussed are of significant importance to the scientific and engineering communities focused on the immobilization of enzymes, proteins, peptides, and other large biological molecules on solid substrates. PMID:23703935

  4. A multichannel monolithic Ge detector system for fluorescence x-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Bucher, J. J.; Allen, P. G.; Edelstein, N. M.; Shuh, D. K.; Madden, N. W.; Cork, C.; Luke, P.; Pehl, D.; Malone, D.

    1996-09-01

    The construction and performance characteristics of a monolithic quad-pixel Ge detector designed specifically for fluorescence x-ray absorption spectroscopy (XAS) at synchrotron radiation sources is described. The detector semiconductor element has an active surface area of 4.0 cm2 that is electrically separated into four 1.0 cm2 pixels, with little interfacial dead volume. The spatial response of the array demonstrates that cross-talk between adjacent pixels is less than 10% for 5.9-keV photons that fall within 0.5 mm of the pixel boundaries. The detector electronics system utilizes preamplifiers built at LBNL with commercial Tennelec Model TC 244 amplifiers. Employing an 55Fe test source (Mn K? , 5.9 keV), energy resolution of better than 200 eV is achieved with a 4 msec peaking time. At 0.5 msec peaking time, pulse pileup results in a 75% throughput efficiency for an incoming count rate of 100 kHz. Initial XAS fluorescence measurements at the beamline 4 wiggler end stations at SSRL show that the detector system has several advantages over commercially available x-ray spectrometers for low-concentration counting applications.

  5. Detrended fluctuation analysis in x-ray photon correlation spectroscopy for determining coarsening dynamics in alloys

    SciTech Connect

    Stadler, Lorenz-M.; Sepiol, Bogdan; Pfau, Bastian; Vogl, Gero [Fakultaet fuer Physik, Institut fuer Materialphysik, Universitaet Wien, Strudlhofgasse 4, A-1090 Wien (Austria); Kantelhardt, Jan W. [Fachbereich Physik und Zentrum fuer Computational Nanoscience, Martin-Luther-Universitaet Halle-Wittenberg, D-06099 Halle (Germany); Weinkamer, Richard [Max Planck Institute of Colloids and Interfaces, Research Campus Golm, D-14424 Potsdam (Germany)

    2006-10-15

    We study the dynamics of precipitate coarsening in phase-separating alloys at late stages of phase separation by x-ray photon correlation spectroscopy (XPCS). For analyzing time series of fluctuating speckle intensities from small-angle scattering of coherent x rays, the method of detrended fluctuation analysis (DFA), which is ideal for determining power-law correlations, is applied. We discuss the application of DFA with respect to XPCS data by means of simulated time series. In particular, the effects of different signal-to-noise ratios are examined. Results from measurements of the two model systems Al-6 at. % Ag at 140 deg. C and Al-9 at. % Zn at 0 deg. C are presented. Since the DFA effectively removes adulterating trends in the data, quantitative agreement with Monte Carlo simulations is obtained. It is verified that two different coarsening mechanisms are predominant in the two systems--coarsening either by diffusion of single atoms or by movement of whole precipitates.

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

    NASA Astrophysics Data System (ADS)

    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)O2 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 [AmO8]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.

  7. X-Ray Photoelectron Spectroscopy Investigation of the Nitrogen Species in Photoactive Perfluorophenylazide-Modified Surfaces

    PubMed Central

    Zorn, Gilad; Liu, Li-Hong; Árnadóttir, Líney; Wang, Hui; Gamble, Lara J.; Castner, David G.; Yan, Mingdi

    2014-01-01

    X-ray Photoelectron Spectroscopy (XPS) was used to characterize the nitrogen species in perfluorophenylazide (PFPA) self-assembled monolayers. PFPA chemistry is a novel immobilization method for tailoring the surface properties of materials. It is a simple route for the efficient immobilization of graphene, proteins, carbohydrates and synthetic polymers onto a variety of surfaces. Upon light irradiation, the azido group in PFPA is converted to a highly reactive singlet nitrene species that readily undergoes CH insertion and C=C addition reactions. Here, the challenge of characterizing the PFPA modified surfaces was addressed by detailed XPS experimental analyses. The three nitrogen peaks detected in the XPS N1s spectra were assigned to amine/amide (400.5 eV) and azide (402.1 and 405.6 eV) species. The observed 2:1 ratio of the areas from the 402.1 eV to 405.6 eV peaks suggests the assignment of the peak at 402.1 eV to the two outer nitrogen atoms in the azido group and assignment of the peak at 405.6 eV to the central nitrogen atom in the azido group. The azide decomposition as the function of x-ray exposure was also determined. Finally, XPS analyses were conducted on patterned graphene to investigate the covalent bond formation between the PFPA and graphene. This study provides strong evidence for the formation of covalent bonds during the PFPA photocoupling process. PMID:24535931

  8. Double-core-hole spectroscopy for chemical analysis with an intense X-ray femtosecond laser

    PubMed Central

    Berrah, Nora; Fang, Li; Murphy, Brendan; Osipov, Timur; Ueda, Kiyoshi; Kukk, Edwin; Feifel, Raimund; van der Meulen, Peter; Salen, Peter; Schmidt, Henning T.; Thomas, Richard D.; Larsson, Mats; Richter, Robert; Prince, Kevin C.; Bozek, John D.; Bostedt, Christoph; Wada, Shin-ichi; Piancastelli, Maria N.; Tashiro, Motomichi; Ehara, Masahiro

    2011-01-01

    Theory predicts that double-core-hole (DCH) spectroscopy can provide a new powerful means of differentiating between similar chemical systems with a sensitivity not hitherto possible. Although DCH ionization on a single site in molecules was recently measured with double- and single-photon absorption, double-core holes with single vacancies on two different sites, allowing unambiguous chemical analysis, have remained elusive. Here we report that direct observation of double-core holes with single vacancies on two different sites produced via sequential two-photon absorption, using short, intense X-ray pulses from the Linac Coherent Light Source free-electron laser and compare it with theoretical modeling. The observation of DCH states, which exhibit a unique signature, and agreement with theory proves the feasibility of the method. Our findings exploit the ultrashort pulse duration of the free-electron laser to eject two core electrons on a time scale comparable to that of Auger decay and demonstrate possible future X-ray control of physical inner-shell processes. PMID:21969540

  9. High resolution X-ray photoelectron spectroscopy of 3-mercaptopropionic acid self-assembled films

    NASA Astrophysics Data System (ADS)

    Gonella, G.; Cavalleri, O.; Terreni, S.; Cvetko, D.; Floreano, L.; Morgante, A.; Canepa, M.; Rolandi, R.

    2004-09-01

    Self-assembled layers of 3-mercaptopropionic acid deposited on Au(1 1 1) from solution have been investigated with synchrotron based, high resolution X-ray photoemission spectroscopy. Results obtained from pristine, X-ray irradiated and heated samples are reported. Pristine samples are characterized by an intense, dominant S 2p state at a binding energy of 162 eV (2p 3/2 level) assigned to thiolates. A less intense doublet around 163.3 eV is tentatively attributed to physisorbed molecules forming a partially occupied upper layer. Irradiation and heating cause the development of a third S 2p doublet around 161 eV which, by comparison with the literature, is assigned to atomic sulfur generated by S-C bond scission. The decrease of the C 1s and O 1s signals with annealing and irradiation, together with the increase of the S 2p state assigned to atomic sulfur, confirms the breaking of the C-S bond.

  10. In-situ X-ray Absorption Spectroscopy of Supported Ru Catalysts in the Aqueous Phase

    SciTech Connect

    Ketchie,W.; Maris, E.; Davis, R.

    2007-01-01

    The size of supported Ru metal particles on various supports was monitored by in situ X-ray absorption spectroscopy under aqueous phase conditions typical of biomass conversion reactions. In particular, Ru/{gamma}-Al{sub 2}O{sub 3}, Ru/C, Ru/TiO{sub 2}, and Ru/SiO{sub 2} were evaluated at the Ru K edge at 473 K in neutral water and 0.4 M NaOH. The as-prepared samples exposed to air contained oxidized Ru that was subsequently reduced by H{sub 2}-saturated water solution. Significant growth of the metal particles was observed on the Ru/{gamma}-Al{sub 2}O{sub 3} and Ru/SiO{sub 2} samples during the aqueous treatments, whereas the Ru/TiO{sub 2} and Ru/C samples were quite stable under the conditions used here. Results from post-treatment X-ray diffraction and surface area analysis revealed major structural changes of the alumina and silica supports. The structural stability of the carbon and titania account for the lack of metal particle growth on those supports. Because a reference Pt/C catalyst revealed metal particle growth under the same conditions, the results for the Ru/C cannot be generalized to other carbon-supported catalysts and underscores the importance of in situ characterization for heterogeneous catalysts in the aqueous phase.

  11. High-rate x-ray spectroscopy in mammography with a CdTe detector: A digital pulse processing approach

    SciTech Connect

    Abbene, L.; Gerardi, G.; Principato, F.; Del Sordo, S.; Ienzi, R.; Raso, G. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy) and INAF/IASF Palermo, Via Ugo La Malfa 153, 90146 Palermo (Italy); Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy); INAF/IASF Palermo, Via Ugo La Malfa 153, 90146 Palermo (Italy); Istituto di Radiologia, Policlinico, 90100 Palermo (Italy); Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy)

    2010-12-15

    Purpose:Direct measurement of mammographic x-ray spectra under clinical conditions is a difficult task due to the high fluence rate of the x-ray beams as well as the limits in the development of high resolution detection systems in a high counting rate environment. In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate x-ray spectroscopy in mammography. Methods: The DPP system performs a digital pile-up inspection and a digital pulse height analysis of the detector signals, digitized through a 14-bit, 100 MHz digitizer, for x-ray spectroscopy even at high photon counting rates. We investigated on the response of the digital detection system both at low (150 cps) and at high photon counting rates (up to 500 kcps) by using monoenergetic x-ray sources and a nonclinical molybdenum anode x-ray tube. Clinical molybdenum x-ray spectrum measurements were also performed by using a pinhole collimator and a custom alignment device. Results: The detection system shows excellent performance up to 512 kcps with an energy resolution of 4.08% FWHM at 22.1 keV. Despite the high photon counting rate (up to 453 kcps), the molybdenum x-ray spectra, measured under clinical conditions, are characterized by a low number of pile-up events. The agreement between the attenuation curves and the half value layer values, obtained from the measured spectra, simulated spectra, and from the exposure values directly measured with an ionization chamber, also shows the accuracy of the measurements. Conclusions: These results make the proposed detection system a very attractive tool for both laboratory research and advanced quality controls in mammography.

  12. Summary: Update to ASTM Guide E 1523 to Charge Control and Charge Referencing Techniques in X-ray Photoelectron Spectroscopy

    SciTech Connect

    Baer, Donald R.

    2005-04-22

    An updated version of the ASTM guide E1523 to the methods to charge control and charge referencing techniques in x-ray photoelectron spectroscopy has been released by ASTM. The guide is meant to acquaint x-ray photoelectron spectroscopy (XPS) users with the various charge control and charge referencing techniques that are and have been used in the acquisition and interpretation of XPS data from surfaces of insulating specimens. The current guide has been expanded to include new references as well as recommendations for reporting information on charge control and charge referencing. The previous version of the document had been published in 1997.

  13. High Resolution Spectroscopy of the X-Ray Emission of GRBs by IMXS-BOSS on the ISS

    Microsoft Academic Search

    L. Piro; L. Colasanti; E. Costa; G. Gandolfi; P. Soffitta; F. Gatti; M. Razeti; D. Pergolesi; R. Vaccarone; G. Testera; M. Pallavicini; A. Ferrari; E. Trussoni; M. Orio; D. Cammon; T. Sanders; M. Galeazzi; A. Szymkowiak; S. Porter

    2001-01-01

    The IMXS (Interstellar and Intergalactic Medium X-ray Survey)-BOSS (gamma-ray Burst Observatory and Spectroscopy Survey) is\\u000a an experiment proposed to fly on the ISS, in order to perform an all-sky X-ray survey with high spectroscopy resolution and\\u000a to measure the spectra of Gamma-Ray Burst (GRB) with an high resolution in the 0.1-10 keV energy band. In a 3 years lifetime\\u000a mission,

  14. Nitrogen-doped carbon spheres: an X-ray absorption near-edge structure spectroscopy study

    NASA Astrophysics Data System (ADS)

    Ray, Sekhar C.; Tetana, Zikhona N.; Erasmus, Rudolph; Pong, Way-Faung; Coville, Neil J.

    2014-04-01

    Carbon spheres (CSs) and low content nitrogen (2.5 and 3.5 at%) doped carbon spheres (NCSs) were synthesized by a pyrolysis process at 900 °C using and CH3CN. The electronic structure and chemical bonding of CSs and NCSs were studied using Raman spectroscopy, valence-band photoemission spectroscopy (VBPES) and X-ray absorption near-edge structure spectroscopy (XANES). XANES spectroscopy showed the effect of carbon and nitrogen bonds and graphitic as well as pyridinic structures on the NCS structure. For the spheres VBPES showed the effect of nitrogen on the spectral shape of the density of states and confirmed the role played by the bonds in controlling the electronic and structural properties of the NCSs. VBPES also showed that both and bands shift towards higher binding energies after N-doping which is consistent with the XANES data. The consistency of the spherical geometry, chemical purity, suitable electronic/bonding structure and the availability of macroscopic quantities of the N-CSs makes these spheres promising new materials for different applications.

  15. Resolution enhancement in coherent x-ray diffraction imaging by overcoming instrumental noise.

    PubMed

    Kim, Chan; Kim, Yoonhee; Song, Changyong; Kim, Sang Soo; Kim, Sunam; Kang, Hyon Chol; Hwu, Yeukuang; Tsuei, Ku-Ding; Liang, Keng San; Noh, Do Young

    2014-11-17

    We report that reference objects, strong scatterers neighboring weak phase objects, enhance the phase retrieval and spatial resolution in coherent x-ray diffraction imaging (CDI). A CDI experiment with Au nano-particles exhibited that the reference objects amplified the signal-to-noise ratio in the diffraction intensity at large diffraction angles, which significantly enhanced the image resolution. The interference between the diffracted x-ray from reference objects and a specimen also improved the retrieval of the phase of the diffraction signal. The enhancement was applied to image NiO nano-particles and a mitochondrion and confirmed in a simulation with a bacteria phantom. We expect that the proposed method will be of great help in imaging weakly scattering soft matters using coherent x-ray sources including x-ray free electron lasers. PMID:25402155

  16. Chapter 1 - The Impacts of X-Ray Absorption Spectroscopy on Understanding Soil Processes and Reaction Mechanisms

    SciTech Connect

    Ginder-Vogel, Matthew; Sparks, Donald L. (Delaware)

    2011-11-17

    During the last two decades, X-ray absorption spectroscopy (XAS) has developed into a mature technique for obtaining the speciation (e.g., oxidation state) and short-range structure of elements present in soils and sediments. XAS encompasses both X-ray absorption near-edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. XAS has a number of advantageous qualities for studying soils and sediments, which include elemental specificity, sensitivity to the local chemical and structural state of an element, and the ability to analyze materials in situ. This information allows accurate determination of oxidation state, type of nearest neighbors, coordination number, bond distance, and orbital symmetries of the X-ray absorbing element. In this review, we examine the application of a wide variety of synchrotron X-ray techniques to fundamental issues in environmental soil chemistry. Additionally, we examine the application of microfocused and time-resolved XAS to determine speciation (e.g., oxidation state and/or local coordination environment) and transformation kinetics of contaminants in heterogeneous environmental systems. During the last three decades, XAS has a played a critical role in furthering our understanding of a myriad of environmental systems and will continue to do so into the foreseeable future.

  17. Oxidation and surface segregation of chromium in Fe-Cr alloys studied by Mössbauer and X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Idczak, R.; Idczak, K.; Konieczny, R.

    2014-09-01

    The room temperature 57Fe Mössbauer and XPS spectra were measured for polycrystalline iron-based Fe-Cr alloys. The spectra were collected using three techniques: the transmission Mössbauer spectroscopy (TMS), the conversion electron Mössbauer spectroscopy (CEMS) and the X-ray photoelectron spectroscopy (XPS). The combination of these experimental techniques allows to determine changes in Cr concentration and the presence of oxygen in bulk, in the 300 nm pre-surface layer and on the surface of the studied alloys.

  18. Relaxation of Cs atomic polarization at surface coatings characterized by X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Kushida, Kotaro; Niwano, Toshihiro; Moriya, Takemasa; Shimizu, Tomohito; Meguro, Kazuki; Nakazawa, Hideki; Hatakeyama, Atsushi

    2015-06-01

    Paraffin coatings on glass slides were investigated through both X-ray photoelectron spectroscopy (XPS) and spin relaxation measurement for cesium (Cs) vapor. The components of the glass substrate, such as silicon and oxygen, existed in the XPS spectra of the coated slides, indicating the imperfection of the prepared paraffin coatings. The substrate was not observed after the annealing of the coatings in Cs vapor, which is known as a “ripening” process for spin relaxation measurement. We found a general trend that effective anti-spin relaxation performance requires high paraffin and low Cs coverage on the surface. We also examined a type of diamond-like carbon film, anticipating the effect of anti-spin relaxation; our attempts have failed to date.

  19. Ge doped HfO{sub 2} thin films investigated by x-ray absorption spectroscopy

    SciTech Connect

    Miotti, Leonardo; Bastos, Karen P.; Lucovsky, Gerald; Radtke, Claudio; Nordlund, Dennis [Department of Physics, North Carolina State University, Box 8202, Raleigh, North Carolina 27695-8202 (United States); Instituto de Quimica, Universidade Federal do Rio Grande do Sul, 91509-900 Porto Alegre (Brazil); Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025 (United States)

    2010-07-15

    The stability of the tetragonal phase of Ge doped HfO{sub 2} thin films on Si(100) was investigated. Hf(Ge)O{sub 2} films with Ge atomic concentrations varying from 0% to 15% were deposited by remote plasma chemical vapor deposition. The atomic structure on the oxide after rapid thermal annealing was investigated by x-ray absorption spectroscopy of the O and Ge K edges and by Rutherford backscattering spectrometry. The authors found that Ge concentrations as low as 5 at. % effectively stabilize the tetragonal phase of 5 nm thick Hf(Ge)O{sub 2} on Si and that higher concentrations are not stable to rapid thermal annealing at temperatures above 750 deg. C.

  20. Analysis of photographs and photo-paintings by energy-dispersive X-ray fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Neiva, Augusto Camara; Marcondes, Marli A.; Pinto, Herbert Prince Favero; Almeida, Paula Aline Durães

    2014-02-01

    A collection of Brazilian family photographs and photo-paintings from the beginning of the XX Century was analyzed by portable EDXRF (Energy-Dispersive X-Ray Fluorescence) spectroscopy. The spectrometer uses a Si-drift Amptek detector and an Oxford Cr-tube or an Oxford W-tube. For every region under analysis, spectra obtained with the W-tube were used to detect all the elements above Al, while the Cr-tube was used to obtain more accurate results for elements between Al and V. Thirty nine elements were identified in the photos, and the origin of the most important ones was discussed. These results can be used for cataloging, preservation and restoring procedures.

  1. X-Ray absorption spectroscopy investigation of 1-alkyl-3-methylimidazolium bromide salts

    SciTech Connect

    D'Angelo, Paola; Zitolo, Andrea; Migliorati, Valentina; Bodo, Enrico; Caminiti, Ruggero [Dipartimento di Chimica, Universita di Roma ''La Sapienza'', P. le A. Moro 5, 00185 Roma (Italy); Aquilanti, Giuliana [Sincrotrone Trieste S.C.p.A s.s. 14, km 163.5, I-34149 Basovizza, Trieste (Italy); Hazemann, Jean Louis; Testemale, Denis [Institut Neel, Departement MCMF, 25 Avenue des Martyrs, 38042 Grenoble and FAME beamline at ESRF, 38043 Grenoble (France); Mancini, Giordano [CASPUR, Inter-University Consortium for Supercomputing in Research, via dei Tizii 6b, 00185 Roma (Italy)

    2011-08-21

    X-ray absorption spectroscopy (XAS) has been used to unveil the bromide ion local coordination structure in 1-alkyl-3-methylimidazolium bromide [C{sub n}mim]Br ionic liquids (ILs) with different alkyl chains. The XAS spectrum of 1-ethyl-3-methylimidazolium bromide has been found to be different from those of the other members of the series, from the butyl to the decyl derivatives, that have all identical XAS spectra. This result indicates that starting from 1-buthyl-3-methylimidazolium bromide the local molecular arrangement around the bromide anion is the same independently from the length of the alkyl chain, and that the imidazolium head groups in the liquid ILs with long alkyl chains assume locally the same orientation as in the [C{sub 4}mim]Br crystal. With this study we show that the XAS technique is an effective direct tool for unveiling the local structural arrangements around selected atoms in ILs.

  2. Comparative study of bandwidths in copper delafossites from x-ray emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Shin, D.; Foord, J. S.; Payne, D. J.; Arnold, T.; Aston, D. J.; Egdell, R. G.; Godinho, K. G.; Scanlon, D. O.; Morgan, B. J.; Watson, G. W.; Mugnier, E.; Yaicle, C.; Rougier, A.; Colakerol, L.; Glans, P. A.; Piper, L. F. J.; Smith, K. E.

    2009-12-01

    The widths of the valence bands in the copper (I) delafossites CuGaO2 , CuInO2 , and CuScO2 have been measured by OK -shell x-ray emission spectroscopy and are compared with previous experimental work on CuAlO2 and CuCrO2 . In agreement with recent density-functional theory calculations it is found that the bandwidth decreases in the series CuAlO2>CuGaO2>CuInO2>CuScO2 . It is shown that states at the top of the valence band are of dominant Cu3dz2 atomic character but with significant mixing with O2p states.

  3. X-ray photoelectron spectroscopy study of chemically-etched Nd-Ce-Cu-O surfaces

    NASA Technical Reports Server (NTRS)

    Vasquez, R. P.; Gupta, A.; Kussmaul, A.

    1991-01-01

    Acetic acid, Br2, and HCl solutions are investigated for removing insulating species from Nd(1.85)Ce(0.15)CuO(4-delta) (NCCO) thin film surfaces. X-ray photoelectron spectroscopy (XPS) shows that the HCl etch is most effective, yielding O 1s spectra comparable to those obtained from samples cleaned in vacuum and a clear Fermi edge in the valence band region. Reduction and oxidation reversibly induces and eliminates, respectively, Fermi level states for undoped samples, but has no clearly observable effect on the XPS spectra for doped samples. Reactivity to air is much less for NCCO compared to hole superconductors, which is attributed to the lack of reactive alkaline earth elements in NCCO.

  4. Chemical State Analysis of Phosphorus Performed by X-ray Emission Spectroscopy.

    PubMed

    Petric, Marko; Bohinc, Rok; Bu?ar, Klemen; Žitnik, Matjaž; Szlachetko, Jakub; Kav?i?, Matjaž

    2015-06-01

    An experimental and theoretical study of phosphorus electronic structure based on high energy resolution X-ray emission spectroscopy was performed. The K? and K? emission spectra of several phosphorus compounds were recorded using monochromatic synchrotron radiation and megaelectronvolt (MeV) proton beam for target excitation. Measured spectra are compared to the results of ab initio quantum chemical calculations based on density functional theory (DFT). Clear correlation between energy position of the K? emission line and the phosphorus formal oxidation state as well as DFT-calculated number of valence electrons is obtained; measured energy shifts are reproduced by the calculations. Chemical sensitivity is increased further by looking at the K? emission spectra probing directly the structure of occupied molecular orbitals. Energies and relative intensities of main components are given together with the calculated average atomic character of the corresponding molecular orbitals involved in transitions. PMID:25927339

  5. A beamline for x-ray laser spectroscopy at the experimental storage ring at GSI

    NASA Astrophysics Data System (ADS)

    Winters, D. F. A.; Bagnoud, V.; Ecker, B.; Eisenbarth, U.; Götte, S.; Kuehl, Th; Neumayer, P.; Spielmann, C.; Stöhlker, Th; Zielbauer, B.

    2013-09-01

    By combining an x-ray laser (XRL) with a heavy-ion storage ring, precision laser spectroscopy of the fine-structure splitting in heavy Li-like ions will be possible. An initial study has been performed to determine the feasibility of a first experiment at the experimental storage ring at GSI in Darmstadt, which also has great potential for the experiments planned for FAIR. We plan to perform a unique, direct and precise measurement of a fine-structure transition in a heavy Li-like ion. Such a measurement will test state-of-the-art atomic structure calculations in strong fields. This endeavour will require that the existing infrastructure is complemented by a dedicated beamline for the XRL. In this paper, we will discuss the details of this project and outline a proof-of-principle experiment.

  6. X-ray photoelectron spectroscopy study of excimer laser treated alumina films

    NASA Astrophysics Data System (ADS)

    Georgiev, D. G.; Kolev, K.; Laude, L. D.; Mednikarov, B.; Starbov, N.

    1998-01-01

    Amorphous alumina layers are deposited on a single crystal Si substrate by a e-gun evaporation technique. These films are then thermally annealed in oxygen to be crystallized and, further, irradiated with an excimer laser beam. At each stage of the film preparation, an x-ray photoelectron spectroscopy analysis is performed at the film surface and in depth, upon ion beam grinding. Results give evidence for the formation of an aluminosilicate upon thermal annealing of the film in oxygen. At the surface itself, this compound is observed to decompose upon excimer laser irradiation at energy densities exceeding 1.75 J/cm2, giving rise to free Si atoms and SiO2, however with complete disappearance of Al atoms. Model photochemical reactions are proposed to explain such transformations.

  7. Visualizing interfacial charge transfer in dye sensitized nanoparticles using x-ray transient absorption spectroscopy.

    SciTech Connect

    Zhang, X. Y.; Smolentsev, G.; Guo, J.; Attenkofer, K.; Kurtz, C.; Jennings, G.; Lockard, J. V.; Stickrath, A. B.; Chen, L. X. (X-Ray Science Division); (Southern Federal Univ.); (Lund Univ.); (Northwestern Univ.)

    2011-01-01

    A molecular level understanding of the structural reorganization accompanying interfacial electron transfer is important for rational design of solar cells. Here we have applied XTA (X-ray transient absorption) spectroscopy to study transient structures in a heterogeneous interfacial system mimicking the charge separation process in dye-sensitized solar cell (DSSC) with Ru(dcbpy){sub 2}(NCS){sub 2} (RuN3) dye adsorbed to TiO{sub 2} nanoparticle surfaces. The results show that the average Ru-NCS bond length reduces by 0.06 {angstrom}, whereas the average Ru-N(dcbpy) bond length remains nearly unchanged after the electron injection. The differences in bond-order change and steric hindrance between two types of ligands are attributed to their structural response in the charge separation. This study extends the application of XTA into optically opaque hybrid interfacial systems relevant to the solar energy conversion.

  8. Fast X-ray Photon Correlation Spectroscopy measurements from the diffusion of concentrated Alpha Crystallin suspensions

    NASA Astrophysics Data System (ADS)

    Karunaratne, Vidanage Nuwan; Debartolo, Janae; Berry, Justin; Lurio, Laurence; Thurston, George; Narayanan, Suresh; Sandy, Alec; Weizeorick, John

    2011-03-01

    Alpha Crystallin constitute up to half of the total protein found in the mammalian eye lens. It has chaperone like behavior and may play a key role in maintaining lens transparency by preventing condensation of other lens proteins. We report here Fast X-ray Photon Correlation Spectroscopy (XPCS) measurements of protein diffusion within concentrated suspensions of Alpha Crystallin. Bovine calf eye lens cortices were homogenized, centrifuged and ultra-filtered to obtain concentrated Alpha Crystallin suspensions. Diffusion of proteins within these suspensions was measured as a function of temperature. The overall observed diffusion rates imply that the proteins exist in a glassy or gel phase, even at concentrations where equivalent hard sphere system would still be liquid. We interpret these results within the context of strongly interacting proteins, with protein-protein interactions possibly mediated by subunit exchange among Alpha Crystallin oligormers. NSF Grant DMR-0706369, ANL/NIU Joint Fellowship.

  9. [Surface and interface analysis of PTCDA/ITO using X-ray photoelectron spectroscopy (XPS)].

    PubMed

    Ou, Gu-ping; Song, Zhen; Gui, Wen-ming; Zhang, Fu-jia

    2006-04-01

    X-ray photoelectron spectroscopy (XPS) of surface and interface of PTCDA/ITO in PTCDA/p-Si organic-on-inorganic photoelectric detector was investigated. From C1s fine spectrum we found that the binding energy of C atoms in perylene rings was 284.6 eV; and the binding energy of C atoms in acid radical was 288.7 eV; moreover, some C atoms were oxidized by O atoms from ITO. The binding energy of O atoms in C=O bonds and C-O-C bonds was 531.5 and 533.4 eV, respectively. At the interface, the peak of high binding energy in C1s spectrum disappeared, and the main peak shifted toward lower binding energy. PMID:16836155

  10. X-ray photoelectron spectroscopy study of radiofrequency-sputtered refractory compound steel interfaces

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.; Brainard, W. A.

    1978-01-01

    Radiofrequency sputtering was used to deposit Mo2C, Mo2B5, and MoSi2 coatings on 440C steel substrates. Both sputter etched and preoxidized substrates were used, and the films were deposited with and without a substrate bias of -300 V. The composition of the coatings was measured as a function of depth by X-ray photoelectron spectroscopy combined with argon ion etching. In the interfacial region there was evidence that bias produced a graded interface in Mo2B5 but not in Mo2C. Oxides of iron and of all film constituents except carbon were presented in all cases but the iron oxide concentration was higher and the layer thicker on the preoxidized substrates. The film and iron oxides were mixed in the MoSi2 and Mo2C films but layered in the Mo2B5 film. The presence of mixed oxides correlates with enhanced film adhesion.

  11. The Anderson-Condon-Shortley Site in X-ray Spectroscopies of Solids

    NASA Astrophysics Data System (ADS)

    Delley, Bernard; Uldry, Anne-Christine

    2014-03-01

    Electronic structures of compounds involving open d- and f- shell are studied frequently by X-ray and electron spectroscopies. The excitation, especially core excitation, is localized on a single site makes this the problem of impurity site states interacting with the continuum of bands. on the other hande, the electron-electron interaction whithin the d- or f- shell leads to a multiplet problem as addressed long ago for isolated atoms. Building on our easy to use program multiX (*), which treats an atom in a general crystal field environment without symmetry analysis, we now address the interaction of this atomic entity with the band continuum. The crossover from atomic to bandlike spectra is the focus of interest. We discuss experimental examples where available and accessible to our methods. Swiss SNF grant 200021-129970 is gratefully acknowledged.

  12. Development of Kilo-Pixel Arrays of Transition-Edge Sensors for X-Ray Spectroscopy

    NASA Technical Reports Server (NTRS)

    Adams, J. S.; Bandler, S. R.; Busch, S. E.; Chervenak, J. A.; Chiao, M. P.; Eckart, M. E.; Ewin, A. J.; Finkbeiner, F. M.; Kelley, R. L.; Kelly, D. P.; Kilbourne, C. A.; Leutenegger, M. A.; Porst, J.-P.; Porter, F. S.; Ray, C. A.; Sadleir, J. E.; Smith, S. J.; Wassell, E. J.; Doriese, W. B.; Fowler, J. W.; Hilton, G. C.; Irwin, K. D.; Reintsema, C. D.; Smith, D. R.; Swetz, D. S.

    2012-01-01

    We are developing kilo-pixel arrays of transition-edge sensor (TES) microcalorimeters for future X-ray astronomy observatories or for use in laboratory astrophysics applications. For example, Athena/XMS (currently under study by the european space agency) would require a close-packed 32x32 pixel array on a 250-micron pitch with < 3.0 eV full-width-half-maximum energy resolution at 6 keV and at count-rates of up to 50 counts/pixel/second. We present characterization of 32x32 arrays. These detectors will be readout using state of the art SQUID based time-domain multiplexing (TDM). We will also present the latest results in integrating these detectors and the TDM readout technology into a 16 row x N column field-able instrument.

  13. Distribution and speciation of bromine in mammalian tissue and fluids by X-ray fluorescence imaging and X-ray absorption spectroscopy.

    PubMed

    Ceko, Melanie J; Hummitzsch, Katja; Hatzirodos, Nicholas; Bonner, Wendy; James, Simon A; Kirby, Jason K; Rodgers, Raymond J; Harris, Hugh H

    2015-05-13

    Bromine is one of the most abundant and ubiquitous trace elements in the biosphere and until recently had not been shown to perform any essential biological function in animals. A recent study demonstrated that bromine is required as a cofactor for peroxidasin-catalysed formation of sulfilimine crosslinks in Drosophila. In addition, bromine dietary deficiency is lethal in Drosophila, whereas bromine replenishment restores viability. The aim of this study was to examine the distribution and speciation of bromine in mammalian tissues and fluids to provide further insights into the role and function of this element in biological systems. In this study we used X-ray fluorescence (XRF) imaging and inductively coupled plasma-mass spectrometry (ICP-MS) to examine the distribution of bromine in bovine ovarian tissue samples, follicular fluid and aortic serum, as well as human whole blood and serum and X-ray absorption spectroscopy (XAS) to identify the chemical species of bromine in a range of mammalian tissue (bovine, ovine, porcine and murine), whole blood and serum samples (bovine, ovine, porcine, murine and human), and marine samples (salmon (Salmo salar), kingfish (Seriola lalandi) and Scleractinian coral). Bromine was found to be widely distributed across all tissues and fluids examined. In the bovine ovary in particular it was more concentrated in the sub-endothelial regions of arterioles. Statistical comparison of the near-edge region of the X-ray absorption spectra with a library of bromine standards led to the conclusion that the major form of bromine in all samples analysed was bromide. PMID:25675086

  14. X-ray photoelectron spectroscopy and luminescent properties of Y2O3:Bi3+ phosphor

    NASA Astrophysics Data System (ADS)

    Jafer, R. M.; Coetsee, E.; Yousif, A.; Kroon, R. E.; Ntwaeaborwa, O. M.; Swart, H. C.

    2015-03-01

    X-ray photoelectron spectroscopy (XPS) results provided proof for the blue and green emission of Bi3+ in the Y2O3:Bi3+ phosphor. The Y2O3:Bi3+ phosphor was successfully prepared by the combustion process during the investigation of down-conversion materials for Si solar cell application. The X-ray diffraction (XRD) patterns indicated that a single-phase cubic crystal structure with the Ia3 space group was formed. X-ray photoelectron spectroscopy (XPS) showed that the Bi3+ ion replaces the Y3+ ion in two different coordination sites in the Y2O3 crystal structure. The O 1s peak shows five peaks, two which correlate with the O2- ion in Y2O3 in the two different sites, two which correlate with O2- in Bi2O3 in the two different sites and the remaining peak relates to hydroxide. The Y 3d spectrum shows two peaks for the Y3+ ion in the Y2O3 structure in two different sites and the Bi 4f spectrum shows the Bi3+ ion in the two different sites in Bi2O3. The photoluminescence (PL) results showed three broad emission bands in the blue and green regions under ultraviolet excitation, which were also present for panchromatic cathodoluminescence (CL) results. These three peaks have maxima at ?3.4, 3.0 and 2.5 eV. The PL emission ?3.0 eV (blue emission) showed two excitation bands centered at ?3.7 and 3.4 eV while the PL emission at ?2.5 eV (green emission) showed a broad excitation band from ?4 to 3.4 eV. The panchromatic CL images were obtained for selected wavelengths at (2.99 ± 0.08) eV (for blue emission) and (2.34 ± 0.06) eV (for green emission). These luminescence results correlate with the XPS results that show that there are two different Bi3+ sites in the host lattice.

  15. X-ray spectroscopy of polar-drive implosions at OMEGA

    NASA Astrophysics Data System (ADS)

    Mancini, Roberto; Johns, H.; Joshi, T.; Mayes, D.; Nasewicz, S.; Hsu, S.; Cobble, J.; Hakel, P.; Tregillis, I.; Baumgaertel, J.; Krasheninnikova, N.; Bradley, P.; Schmitt, M.

    2013-10-01

    In a series of polar-drive implosions performed at OMEGA several x-ray spectrometers were fielded to record the signal from Ar and Ti tracers added to the core and shell, respectively. The instruments included time-integrated (XRS) and streaked (SSCA) spectrometers as well as gated monochromatic imagers (MMI). Analysis of the Ar streaked data produced the time-history of density and temperature in the core. The gated images provided information about symmetry along both the polar axis and the equatorial plane lines-of-sight. In addition, a generalized Abel inversion of narrow-band images and detailed analysis of spatially resolved spectra extracted from spectrally resolved images recorded with MMI produced spatial distirutions of plasma conditions and mix (T. Nagayama et al., Phys. Plasmas 19, 082705 (2012)). Comparisons were made with results from post-processed 3D simulations to provide further insight into the interpretation of the experimental results and to constrain the simulation physics model. In a series of polar-drive implosions performed at OMEGA several x-ray spectrometers were fielded to record the signal from Ar and Ti tracers added to the core and shell, respectively. The instruments included time-integrated (XRS) and streaked (SSCA) spectrometers as well as gated monochromatic imagers (MMI). Analysis of the Ar streaked data produced the time-history of density and temperature in the core. The gated images provided information about symmetry along both the polar axis and the equatorial plane lines-of-sight. In addition, a generalized Abel inversion of narrow-band images and detailed analysis of spatially resolved spectra extracted from spectrally resolved images recorded with MMI produced spatial distirutions of plasma conditions and mix (T. Nagayama et al., Phys. Plasmas 19, 082705 (2012)). Comparisons were made with results from post-processed 3D simulations to provide further insight into the interpretation of the experimental results and to constrain the simulation physics model. This work was supported by LANL contract 156715.

  16. Electronic structure of the organic semiconductor Alq3 (aluminum tris-8-hydroxyquinoline) from soft x-ray spectroscopies and density functional theory calculations.

    PubMed

    DeMasi, A; Piper, L F J; Zhang, Y; Reid, I; Wang, S; Smith, K E; Downes, J E; Peltekis, N; McGuinness, C; Matsuura, A

    2008-12-14

    The element-specific electronic structure of the organic semiconductor aluminum tris-8-hydroxyquinoline (Alq(3)) has been studied using a combination of resonant x-ray emission spectroscopy, x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, and density functional theory (DFT) calculations. Resonant and nonresonant x-ray emission spectroscopy were used to measure directly the carbon, nitrogen and oxygen 2p partial densities of states in Alq(3), and good agreement was found with the results of DFT calculations. Furthermore, resonant x-ray emission at the carbon K-edge is shown to be able to measure the partial density of states associated with individual C sites. Finally, comparison of previous x-ray emission studies and the present data reveal the presence of clear photon-induced damage in the former. PMID:19071937

  17. Electronic Structure of the Organic Semiconductor Alq3 (aluminum tris-8-hydroxyquinoline) from Soft X-ray Spectroscopies and Density Functional Theory Calculations

    SciTech Connect

    DeMasi, A.; Piper, L; Zhang, Y; Reid, I; Wang, S; Smith, K; Downes, J; Pelkekis, N; McGuinness, C; Matsuura, A

    2008-01-01

    The element-specific electronic structure of the organic semiconductor aluminum tris-8-hydroxyquinoline (Alq3) has been studied using a combination of resonant x-ray emission spectroscopy, x-ray photoelectron spectroscopy, x-ray absorption spectroscopy, and density functional theory (DFT) calculations. Resonant and nonresonant x-ray emission spectroscopy were used to measure directly the carbon, nitrogen and oxygen 2p partial densities of states in Alq3, and good agreement was found with the results of DFT calculations. Furthermore, resonant x-ray emission at the carbon K-edge is shown to be able to measure the partial density of states associated with individual C sites. Finally, comparison of previous x-ray emission studies and the present data reveal the presence of clear photon-induced damage in the former.

  18. Ultraviolet high-resolution spectroscopy of the X-ray binary Sk 160/SMC X-1

    NASA Technical Reports Server (NTRS)

    Hammerschlag-Hensberge, G.; Kallman, T. R.; Howarth, I. D.

    1984-01-01

    High-resolution IUE spectra of Sk 160, the optical counterpart of the X-ray source SMC X-1, show substantial variations with orbital phase of the resonance P Cygni profiles. These variations are ascribed to the changing ionization state in the stellar wind caused by the X-rays emitted by the companion, as suggested by Hatchett and McCray and first established for the galactic X-ray binary Vela X-1. Furthermore, the profile observed during X-ray eclipse differs significantly from profiles of similar stars in the absence of X-ray ionization.

  19. Methods development for diffraction and spectroscopy studies of metalloenzymes at X-ray free-electron lasers.

    PubMed

    Kern, Jan; Hattne, Johan; Tran, Rosalie; Alonso-Mori, Roberto; Laksmono, Hartawan; Gul, Sheraz; Sierra, Raymond G; Rehanek, Jens; Erko, Alexei; Mitzner, Rolf; Wernet, Phillip; Bergmann, Uwe; Sauter, Nicholas K; Yachandra, Vittal; Yano, Junko

    2014-07-17

    X-ray free-electron lasers (XFELs) open up new possibilities for X-ray crystallographic and spectroscopic studies of radiation-sensitive biological samples under close to physiological conditions. To facilitate these new X-ray sources, tailored experimental methods and data-processing protocols have to be developed. The highly radiation-sensitive photosystem II (PSII) protein complex is a prime target for XFEL experiments aiming to study the mechanism of light-induced water oxidation taking place at a Mn cluster in this complex. We developed a set of tools for the study of PSII at XFELs, including a new liquid jet based on electrofocusing, an energy dispersive von Hamos X-ray emission spectrometer for the hard X-ray range and a high-throughput soft X-ray spectrometer based on a reflection zone plate. While our immediate focus is on PSII, the methods we describe here are applicable to a wide range of metalloenzymes. These experimental developments were complemented by a new software suite, cctbx.xfel. This software suite allows for near-real-time monitoring of the experimental parameters and detector signals and the detailed analysis of the diffraction and spectroscopy data collected by us at the Linac Coherent Light Source, taking into account the specific characteristics of data measured at an XFEL. PMID:24914169

  20. Low-Dimensional Water on Ru(0001)Model System for X-ray Absorption Spectroscopy Studies of Liquid Water

    SciTech Connect

    Nordlund, D

    2012-02-14

    We present an x-ray absorption spectroscopy results for fully broken to a complete H-bond network of water molecules on Ru(0001) by varying the morphology from isolated water molecules via two-dimensional clusters to a fully covered monolayer as probed by scanning tunneling microscopy. The sensitivity of x-ray absorption to the symmetry of H-bonding is further elucidated for the amino (-NH{sub 2}) group in glycine adsorbed on Cu(110) where the E-vector is parallel either to the NH donating an H-bond or to the non-H-bonded NH. The results give further evidence for the interpretation of the various spectral features of liquid water and for the general applicability of x-ray absorption spectroscopy to analyze H-bonded systems.

  1. Recent progress in space- and time-resolved x-ray spectroscopy of laser-produced plasmas (abstract)

    NASA Astrophysics Data System (ADS)

    Young, B. K. F.

    1990-10-01

    New diagnostic techniques have provided measurement of relatively gradient-free x-ray spectra from high-powered laser-produced plasmas. Simultaneously space- and time-resolved x-ray spectra were measured from a variety of microdot plasmas using an array of multiframe, imaging, electronically gated x-ray crystal spectrometers with 100 ps time resolution. A multiframed, multicolored gated x-ray pinhole camera provided measurement of the plasma uniformity. A four-frame holographic interferometer was used to measure the electron density profile. Conventional x-ray streaked crystal spectrographs, spatially resolved x-ray (film) spectrometer, and pinhole cameras supplemented these new diagnostics. The instruments allow detailed studies of both the population kinetics of highly charged ions in dense plasmas and the hydrodynamics of laser-produced plasmas for the first time. The new diagnostics are described including data from ongoing experiments. Work was performed in part under the auspices of the U.S. Dept. of Energy by LLNL under Contract No. W-7405-Eng-48.

  2. High Resolution X-Ray Spectroscopy of the Local Hot Gas along the 3C 273 Sightline

    NASA Astrophysics Data System (ADS)

    Fang, Taotao; Jiang, Xiaochuan

    2014-04-01

    X-ray observations of highly ionized metal absorption lines at z = 0 provide critical information on the hot gas distribution in and around the Milky Way. We present a study of more than 10 yr of Chandra and XMM-Newton observations of 3C 273, one of the brightest extragalactic X-ray sources. Compared with previous works, we obtain much tighter constraints on the physical properties of the X-ray absorber. We also find a large, non-thermal velocity at ~100-150 km s-1, the main reason for the higher line equivalent width when compared with other sightlines. Using joint analysis with X-ray emission and ultraviolet observations, we derive a size of 5-15 kpc and a temperature of (1.5-1.8) × 106 K for the X-ray absorber. The 3C 273 sightline passes through a number of Galactic structures, including radio loops I and IV, the North Polar Spur, and the neighborhood of the newly discovered "Fermi bubbles." We argue that the X-ray absorber is unlikely to be associated with the nearby radio loops I and IV; however, the non-thermal velocity can be naturally explained as the result of the expansion of the "Fermi bubbles." Our data imply a shock-expansion velocity of 200-300 km s-1. Our study indicates a likely complex environment for the production of the Galactic X-ray absorbers along different sightlines, and highlights the significance of probing galactic feedback with high resolution X-ray spectroscopy.

  3. A study of the elemental composition of diabases by instrumental neutron activation and X-ray fluorescence analysis

    Microsoft Academic Search

    A. V. Gurevich; Z. V. Vikhrova; V. Ya Vyropayev; V. I. Drynkin; D. I. Leipunskaya; I. Ya. Shirokova

    1980-01-01

    The distribution of the elemental composition was studied mainly for microelements in the diabases of the Pechenga suite subjected\\u000a to various changes. Investigations were conducted by a combination of instrumental neutron activation INAA and X-ray fluoresence\\u000a XRFA analyses. The INAA was conducted with sample weights of 20–100 mg exposed to irradiation in a nuclear reactor by a flux\\u000a of neutrons

  4. L-Edge X-ray Absorption Spectroscopy of Dilute Systems Relevant to Metalloproteins Using an X-ray Free-Electron Laser.

    PubMed

    Mitzner, Rolf; Rehanek, Jens; Kern, Jan; Gul, Sheraz; Hattne, Johan; Taguchi, Taketo; Alonso-Mori, Roberto; Tran, Rosalie; Weniger, Christian; Schröder, Henning; Quevedo, Wilson; Laksmono, Hartawan; Sierra, Raymond G; Han, Guangye; Lassalle-Kaiser, Benedikt; Koroidov, Sergey; Kubicek, Katharina; Schreck, Simon; Kunnus, Kristjan; Brzhezinskaya, Maria; Firsov, Alexander; Minitti, Michael P; Turner, Joshua J; Moeller, Stefan; Sauter, Nicholas K; Bogan, Michael J; Nordlund, Dennis; Schlotter, William F; Messinger, Johannes; Borovik, Andrew; Techert, Simone; de Groot, Frank M F; Föhlisch, Alexander; Erko, Alexei; Bergmann, Uwe; Yachandra, Vittal K; Wernet, Philippe; Yano, Junko

    2013-10-01

    L-edge spectroscopy of 3d transition metals provides important electronic structure information and has been used in many fields. However, the use of this method for studying dilute aqueous systems, such as metalloenzymes, has not been prevalent because of severe radiation damage and the lack of suitable detection systems. Here we present spectra from a dilute Mn aqueous solution using a high-transmission zone-plate spectrometer at the Linac Coherent Light Source (LCLS). The spectrometer has been optimized for discriminating the Mn L-edge signal from the overwhelming O K-edge background that arises from water and protein itself, and the ultrashort LCLS X-ray pulses can outrun X-ray induced damage. We show that the deviations of the partial-fluorescence yield-detected spectra from the true absorption can be well modeled using the state-dependence of the fluorescence yield, and discuss implications for the application of our concept to biological samples. PMID:24466387

  5. L-Edge X-ray Absorption Spectroscopy of Dilute Systems Relevant to Metalloproteins Using an X-ray Free-Electron Laser

    PubMed Central

    Mitzner, Rolf; Rehanek, Jens; Kern, Jan; Gul, Sheraz; Hattne, Johan; Taguchi, Taketo; Alonso-Mori, Roberto; Tran, Rosalie; Weniger, Christian; Schröder, Henning; Quevedo, Wilson; Laksmono, Hartawan; Sierra, Raymond G.; Han, Guangye; Lassalle-Kaiser, Benedikt; Koroidov, Sergey; Kubicek, Katharina; Schreck, Simon; Kunnus, Kristjan; Brzhezinskaya, Maria; Firsov, Alexander; Minitti, Michael P.; Turner, Joshua J.; Moeller, Stefan; Sauter, Nicholas K.; Bogan, Michael J.; Nordlund, Dennis; Schlotter, William F.; Messinger, Johannes; Borovik, Andrew; Techert, Simone; de Groot, Frank M. F.; Föhlisch, Alexander; Erko, Alexei; Bergmann, Uwe; Yachandra, Vittal K.; Wernet, Philippe; Yano, Junko

    2013-01-01

    L-edge spectroscopy of 3d transition metals provides important electronic structure information and has been used in many fields. However, the use of this method for studying dilute aqueous systems, such as metalloenzymes, has not been prevalent because of severe radiation damage and the lack of suitable detection systems. Here we present spectra from a dilute Mn aqueous solution using a high-transmission zone-plate spectrometer at the Linac Coherent Light Source (LCLS). The spectrometer has been optimized for discriminating the Mn L-edge signal from the overwhelming O K-edge background that arises from water and protein itself, and the ultrashort LCLS X-ray pulses can outrun X-ray induced damage. We show that the deviations of the partial-fluorescence yield-detected spectra from the true absorption can be well modeled using the state-dependence of the fluorescence yield, and discuss implications for the application of our concept to biological samples. PMID:24466387

  6. Local electronic states of Fe4N films revealed by x-ray absorption spectroscopy and x-ray magnetic circular dichroism

    NASA Astrophysics Data System (ADS)

    Ito, Keita; Toko, Kaoru; Takeda, Yukiharu; Saitoh, Yuji; Oguchi, Tamio; Suemasu, Takashi; Kimura, Akio

    2015-05-01

    We performed x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) measurements at Fe L2,3 and N K-edges for Fe4N epitaxial films grown by molecular beam epitaxy. In order to clarify the element specific local electronic structure of Fe4N, we compared experimentally obtained XAS and XMCD spectra with those simulated by a combination of a first-principles calculation and Fermi's golden rule. We revealed that the shoulders observed at Fe L2,3-edges in the XAS and XMCD spectra were due to the electric dipole transition from the Fe 2p core-level to the hybridization state generated by ?* anti-bonding between the orbitals of N 2p at the body-centered site and Fe 3d on the face-centered (II) sites. Thus, the observed shoulders were attributed to the local electronic structure of Fe atoms at II sites. As to the N K-edge, the line shape of the obtained spectra was explained by the dipole transition from the N 1s core-level to the hybridization state formed by ?* and ?* anti-bondings between the Fe 3d and N 2p orbitals. This hybridization plays an important role in featuring the electronic structures and physical properties of Fe4N.

  7. Quantitative analysis of deconvolved X-ray absorption near-edge structure spectra: a tool to push the limits of the X-ray absorption spectroscopy technique.

    PubMed

    D'Angelo, Paola; Migliorati, Valentina; Persson, Ingmar; Mancini, Giordano; Della Longa, Stefano

    2014-09-15

    A deconvolution procedure has been applied to K-edge X-ray absorption near-edge structure (XANES) spectra of lanthanoid-containing solid systems, namely, hexakis(dmpu)praseodymium(III) and -gadolinium(III) iodide. The K-edges of lanthanoids cover the energy range 38 (La)-65 (Lu) keV, and the large widths of the core-hole states lead to broadening of spectral features, reducing the content of structural information that can be extracted from the raw X-ray absorption spectra. Here, we demonstrate that deconvolution procedures allow one to remove most of the instrumental and core-hole lifetime broadening in the K-edge XANES spectra of lanthanoid compounds, highlighting structural features that are lost in the raw data. We show that quantitative analysis of the deconvolved K-edge XANES spectra can be profitably used to gain a complete local structural characterization of lanthanoid-containing systems not only for the nearest neighbor atoms but also for higher-distance coordination shells. PMID:25171598

  8. The Neutron star Interior Composition ExploreR (NICER): an Explorer mission of opportunity for soft x-ray timing spectroscopy

    NASA Astrophysics Data System (ADS)

    Gendreau, Keith C.; Arzoumanian, Zaven; Okajima, Takashi

    2012-09-01

    The Neutron star Interior Composition ExploreR (NICER) is a proposed NASA Explorer Mission of Opportunity dedicated to the study of the extraordinary gravitational, electromagnetic, and nuclear-physics environments embodied by neutron stars. NICER will explore the exotic states of matter within neutron stars, where density and pressure are higher than in atomic nuclei, confronting theory with unique observational constraints. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft (0.2-12 keV) X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena, and the mechanisms that underlie the most powerful cosmic particle accelerators known. NICER will achieve these goals by deploying, following launch in December 2016, an X-ray timing and spectroscopy instrument as an attached payload aboard the International Space Station (ISS). A robust design compatible with the ISS visibility, vibration, and contamination environments allows NICER to exploit established infrastructure with low risk. Grazing-incidence optics coupled with silicon drift detectors, actively pointed for a full hemisphere of sky coverage, will provide photon-counting spectroscopy and timing registered to GPS time and position, with high throughput and relatively low background. In addition to advancing a vital multi-wavelength approach to neutron star studies through coordination with radio and ?-ray observations, NICER will provide a rapid-response capability for targeting of transients, continuity in X-ray timing astrophysics investigations post-RXTE through a proposed Guest Observer program, and new discovery space in soft X-ray timing science.

  9. The Calan-Yale Deep Extragalactic Research (CYDER) Survey: Optical Properties and Deep Spectroscopy of Serendipitous X-ray Sources

    E-print Network

    Ezequiel Treister; Francisco Castander; Thomas Maccarone; Eric Gawiser; Paolo Coppi; C. Megan Urry; Jose Maza; David Herrera; Valentino Gonzalez; Carlos Montoya; Pedro Pineda

    2004-11-12

    We present the first results from the Cal\\'an-Yale Deep Extragalactic Research (CYDER) survey. The main goal of this survey is to study serendipitous X-ray sources detected by Chandra in an intermediate flux range ($10^{-15}-10^{-12}$ ergs s$^{-1}$) that comprises most of the X-ray background. 267 X-ray sources spread over 5 archived fields were detected. The $\\log N-\\log S$ distribution obtained for this sample is consistent with the results of other surveys. Deep $V$ and $I$ images were taken of these fields in order to calculate X-ray-to-optical flux ratios. Identifications and redshifts were obtained for 106 sources using optical spectroscopy from 8-m class telescopes to reach the optically faintest sources, to the same level as deeper X-ray fields like the Chandra Deep Fields, showing that the nature of sources detected depends mostly on the optical limit for spectroscopy. In general, sources optically classified as obscured Active Galactic Nuclei (AGNs) have redder optical colors than unobscured AGN. A rough correlation between $f_X/f_{\\rm opt}$ and hard X-ray luminosity was found for obscured AGN confirming the prediction by existing models that in obscured AGN the optical light is completely dominated by the host galaxy. The previously claimed decrease of the obscured to unobscured AGN ratio with increasing X-ray luminosity is observed. However, this correlation can be explained as a selection effect caused by the lower optical flux of obscured AGN. Comparison between the observed $N_H$ distribution and predictions by existing models shows that the sample appears complete up to $N_H<3\\times 10^{22}$ cm$^{-2}$, while for more obscured sources incompleteness plays an important role in the observed obscured to unobscured AGN ratio.

  10. A Fast, Versatile Nanoprobe for Complex Materials: The Sub-micron Resolution X-ray Spectroscopy Beamline at NSLS-II (491st Brookhaven Lecture)

    SciTech Connect

    Thieme, Juergen [BNL Photon Sciences Directorate

    2014-02-06

    Time is money and for scientists who need to collect data at research facilities like Brookhaven Lab’s National Synchrotron Light Source (NSLS), “beamtime” can be a precious commodity. While scanning a complex material with a specific technique and standard equipment today would take days to complete, researchers preparing to use brighter x-rays and the new sub-micron-resolution x-ray spectroscopy (SRX) beamline at the National Synchrotron Light Source II (NSLS-II) could scan the same sample in greater detail with just a few hours of beamtime. Talk about savings and new opportunities for researchers! Users will rely on these tools for locating trace elements in contaminated soils, developing processes for nanoparticles to deliver medical treatments, and much more. Dr. Thieme explains benefits for next-generation research with spectroscopy and more intense x-rays at NSLS-II. He discusses the instrumentation, features, and uses for the new SRX beamline, highlighting its speed, adjustability, and versatility for probing samples ranging in size from millimeters down to the nanoscale. He will talk about complementary beamlines being developed for additional capabilities at NSLS-II as well.

  11. In situ study of an oxidation reaction on a Pt/C electrode by ambient pressure hard X-ray photoelectron spectroscopy

    SciTech Connect

    Takagi, Yasumasa, E-mail: ytakagi@ims.ac.jp; Uemura, Yohei; Yokoyama, Toshihiko [Department of Molecular Structure, Institute for Molecular Science, Myodaiji-cho, Okazaki, Aichi 444-8585 (Japan); The Graduate University for Advanced Studies (SOKENDAI), Myodaiji-cho, Okazaki, Aichi 444-8585 (Japan); Wang, Heng [Department of Molecular Structure, Institute for Molecular Science, Myodaiji-cho, Okazaki, Aichi 444-8585 (Japan); Ikenaga, Eiji; Ohashi, Haruhiko; Senba, Yasunori; Yumoto, Hirokatsu; Yamazaki, Hiroshi; Goto, Shunji [Japan Synchrotron Radiation Research Institute, SPring-8, Koto, Sayo, Hyogo 679-5198 (Japan); Sekizawa, Oki; Iwasawa, Yasuhiro [Innovation Research Center for Fuel Cells, The University of Electro-Communications, Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Uruga, Tomoya [Japan Synchrotron Radiation Research Institute, SPring-8, Koto, Sayo, Hyogo 679-5198 (Japan); Innovation Research Center for Fuel Cells, The University of Electro-Communications, Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Tada, Mizuki [Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan)

    2014-09-29

    We have constructed an ambient pressure X-ray photoelectron spectroscopy instrument that uses hard X-ray radiation at the high-performance undulator beamline BL36XU of SPring-8. The dependence of the Au 4f peak intensity from Au foil on the ambient N{sub 2} pressure was measured. At a photon energy of 7.94?keV, the Au 4f peak intensity maintained 40% at 3000?Pa compared with that at high vacuum. We designed a polymer electrolyte fuel cell that allows us to perform X-ray photoelectron spectroscopy measurements of an electrode under working conditions. The oxidized Pt peaks were observed in the Pt 3d{sub 5/2} level of Pt nanoparticles in the cathode, and the peaks clearly depended on the applied voltage between the anode and cathode. Our apparatus can be applied as a valuable in situ tool for the investigation of the electronic states and adsorbed species of polymer electrolyte fuel cell electrode catalysts under the reaction conditions.

  12. Comparative Experimental Study of x-ray Absorption Spectroscopy and Electron Energy Loss Spectroscopy on Passivated U Surfaces

    SciTech Connect

    Nelson, Art J.; Moberlychan, W.J.; Bliss, R.A.; Siekhaus, W.J.; Felter, T.E. [CMS MSTD, Lawrence Livermore National Laboratory, Livermore, California (United States); Denlinger, J.D. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2007-07-01

    X-ray absorption spectroscopy and electron energy loss spectroscopy are complementary analytical techniques on energy and spatial resolution. These techniques are based on the same fundamental physical process of core excitation with either an incident photon or incident electron. In the proper experimental configuration the electron and photon inelastic scattering amplitudes are comparable and thus the x-ray and electron absorption edges look identical. We have applied these two complementary analytical techniques to investigate the electronic structure of C ion implanted U. Implantation of C{sup +} ions into {sup 238}U has been shown to produce a physically and chemically modified surface layer that passivates the surface preventing further air oxidation and corrosion. Comparison of the resultant spectra reveal that transitions between the initial state and a series of final states yield numerous strong features at the absorption edge that can provide structural information and information on the local chemical environment, including the character of the U 5f state. (authors)

  13. Novel parallel vacuum ultra-violet/X-ray fluorescence spectrometer

    NASA Astrophysics Data System (ADS)

    Erko, A.; Firsov, A.; Senf, F.

    2012-01-01

    Novel instrumentation developments in X-ray spectroscopy for parallel spectral measurements with soft X-rays are described. The significant performance improvements are achieved utilising Fresnel diffraction from structures built onto the surface of a total external reflection mirror. An array of reflection zone plates was tested as a wavelength-dispersive fluorescence spectrometer for soft X-rays in the energy range of 100-550 eV.

  14. Quantitation of the global secondary structure of globular proteins by FTIR spectroscopy: Comparison with X-ray crystallographic structure

    Microsoft Academic Search

    Thomas F. Kumosinski; Joseph J. Unruh

    1996-01-01

    Fourier transform infrared spectroscopy (FTIR) is potentially a powerful tool for determining the global secondary structure of proteins in solution, providing the spectra are analyzed using a statistically and theoretically justified methodology. We have performed FTIR experiments on 14 globular proteins and two synthetic polypeptides whose X-ray crystal structures are known to exhibit varying types and amounts of secondary structures.

  15. An electrochemical enrichment procedure for the determination of heavy metals by total-reflection X-ray fluorescence spectroscopy

    Microsoft Academic Search

    A. Ritschel; P Wobrauschek; E Chinea; F Grass; Ch Fabjan

    1999-01-01

    An electrolytic separation and enrichment technique was developed for the determination of trace elements by total-reflection X-ray fluorescence spectroscopy (TXRF). The elements of interest are electrodeposited out of the sample solution onto a solid, polished disc of pure niobium which is used as sample carrier for the TXRF measurement. The electrochemical deposition leads to a high enrichment of the analytes

  16. StructureProperty Correlations in CoFeSiO2 Nanogranular Films Utilizing x-Ray Photoelectron Spectroscopy

    E-print Network

    Laughlin, David E.

    integration of advanced fossil fuel and renewable energy sources is therefore of increasing impor- tance.3-angle scattering, x-ray photoelectron spectroscopy INTRODUCTION Recent reports by the US Department of Energy and Magnetic Materials Team, Functional Materials Development Division, National Energy Technology Laboratory

  17. Surface Layers on Chromium in Sulfuric Acid Solutions of Organic Substances: An X-ray Photoelectron Spectroscopy Study

    Microsoft Academic Search

    V. A. Safonov; E. N. Lubnin; L. N. Vykhodtseva; G. E. Chusova; Yu. M. Polukarov

    2001-01-01

    Surface layers formed at a contact of chromium with sulfuric acid solutions containing some organic substances (sodium oxalate, dimethylformamide, methanol) are analyzed by the X-ray photoelectron spectroscopy method. The layers are shown to contain products of deep destruction of organic molecules, i.e. carbon species and those containing functional groups. The data obtained point to the electrocatalytic activity of chromium in

  18. First-principles core-level X-ray photoelectron spectroscopy calculation on arsenic defects in silicon crystal

    SciTech Connect

    Kishi, Hiroki; Miyazawa, Miki; Matsushima, Naoki; Yamauchi, Jun [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama-shi, Kanagawa-ken 223-8522 (Japan)

    2014-02-21

    We investigate the X-ray photoelectron spectroscopy (XPS) binding energies of As 3d in Si for various defects in neutral and charged states by first-principles calculation. It is found that the complexes of a substitutional As and a vacancy in charged and neutral states explain the experimentally observed unknown peak very well.

  19. Probing Reaction Dynamics of Transition-Metal Complexes in Solution via Time-Resolved Soft X-ray Spectroscopy

    SciTech Connect

    Huse, Nils; Kim, Tae Kyu; Khalil, Munira; Jamula, Lindsey; McCusker, James K.; Schoenlein, Robert W.

    2010-05-02

    We report the first time-resolved soft x-ray measurements of solvated transition-metal complexes. L-edge spectroscopy directly probes dynamic changes in ligand-field splitting of 3d orbitals associated with the spin transition, and mediated by changes in ligand-bonding.

  20. Structural disorder in KNbO{sub 3} crystal from X-ray diffraction and EXAFS spectroscopy

    SciTech Connect

    Shuvaeva, V.A. [Rostov State Univ., Rostov-na-Donu (Russian Federation); Antipin, M.Yu. [Russian Academy of Sciences, Moscow (Russian Federation)

    1995-05-01

    The arrangement of Nb atoms in the KNbO{sub 3} crystal structure was studied using X-ray diffraction and EXAFS spectroscopy. At room temperature, the Nb atoms are displaced from the centers of oxygen octahedra in the direction close to that of the polar axis. Considerable changes in the local structure with temperature were found. 16 refs., 3 figs.

  1. X ray laser spectroscopy at the ESR: a proposed novel tool for the investigation of exotic isotopes

    NASA Astrophysics Data System (ADS)

    Borneis, S.; Becker de Moos, B.; Kluge, H. J.; Kühl, T.; Marx, D.; Nickles, P. V.; Neumayer, P.; Sandner, W.; Seelig, W.

    2000-08-01

    Novel X-ray laser sources driven by short-pulse high power lasers can provide intense beams of radiation at fixed energy. In combination with the Doppler-tuning possible at the ESR storage ring, this can be utilized for precision spectroscopy of highly charged ions. The sensitivity should be sufficient to apply this technique to lithium-like radioactive ions.

  2. Microbeam x-ray absorption spectroscopy study of chromium in large-grain uranium dioxide fuel

    NASA Astrophysics Data System (ADS)

    Mieszczynski, C.; Kuri, G.; Bertsch, J.; Martin, M.; Borca, C. N.; Delafoy, Ch; Simoni, E.

    2014-09-01

    Synchrotron-based microprobe x-ray absorption spectroscopy (XAS) has been used to study the local atomic structure of chromium in chromia-doped uranium dioxide (UO2) grains. The specimens investigated were a commercial grade chromia-doped UO2 fresh fuel pellet, and materials from a spent fuel pellet of the same batch, irradiated with an average burnup of ~40?MW d kg-1. Uranium L3-edge and chromium K-edge XAS have been measured, and the structural environments of central uranium and chromium atoms have been elucidated. The Fourier transform of uranium L3-edge extended x-ray absorption fine structure shows two well-defined peaks of U-O and U-U bonds at average distances of 2.36 and 3.83?Å. Their coordination numbers are determined as 8 and 11, respectively. The chromium Fourier transform extended x-ray absorption fine structure of the pristine UO2 matrix shows similar structural features with the corresponding spectrum of the irradiated spent fuel, indicative of analogous chromium environments in the two samples studied. From the chromium XAS experimental data, detectable next neighbor atoms are oxygen and uranium of the cation-substituted UO2 lattice, and two distinct subshells of chromium and oxygen neighbors, possibly because of undissolved chromia particles present in the doped fuels. Curve-fitting analyses using theoretical amplitude and phase-shift functions of the closest Cr-O shell and calculations with ab initio computer code FEFF and atomic clusters generated from the chromium-dissolved UO2 structure have been carried out. There is a prominent reduction in the length of the adjacent Cr-O bond of about 0.3?Å in chromia-doped UO2 compared with the ideal U-O bond length in standard UO2 that would be expected because of the change in effective Coulomb interactions resulting from replacing U4+ with Cr3+ and their ionic size differences. The contraction of shortest Cr-U bond is ~0.1?Å relative to the U-U bond length in bulk UO2. The difference in the local chromium environment between fresh and irradiated UO2 is discussed based on the comparison of quantitative structural information obtained from the two chromia-doped fuel samples analyzed.

  3. Polarized X-Ray Absorption Spectroscopy Studies of Copper in High Temperature Superconductors

    NASA Astrophysics Data System (ADS)

    Mini, Susan M.

    One can take advantage of the linearly polarized nature of the x-rays from a synchrotron to study the electronic and structural properties of single crystals or magnetically aligned powders. Since the advent of layered copper oxide compounds as high temperature superconductors (1) the structures of La_{rm 2-x}Sr _{rm x}CuO _4, Nd_{rm 2-x }Ce_{rm x}CuO _4 and YBa_2Cu _3O_{rm 7-y} have been of extreme interest. In this study, the powder samples of these compounds were magnetically aligned such that the electric vector was either perpendicular or parallel to the crystallographic c axis. The results of polarized XANES (X-ray Absorption Near Edge Spectroscopy) measurements at the copper K-edge (8979 eV) of all three structures will be presented. The EXAFS (Extended X-ray Absorption Fine Structure) of magnetically aligned YBa_2Cu _3O_{6.9} were used to characterize the local structure as well as study the structural changes of the Cu1-O4 and Cu2-O4 bonds in as a function of temperature (20 to 300 K). In this manner, the Cu1-O4 and Cu2-O4 bonds, which are thought to play a role in the superconductivity of the sample, are distinguishable. The complementary technique of XANES is used to study the electronic structure of the superconducting copper oxides as well as alkali cuprates M^{ rm I}CuO_2 (M = Na, K, Rb and Cs) and rare earth copper oxides RE _2CuO_4 (RE = Pr, Nd, Sm, Eu and Gd). A method (2) for determining the effective charge is described and applied to the copper oxides. ftn 1. J. G. Bednorz and K. A. Muller; Z Phys. B64, 189 (1986). 2. E. E. Alp, G L. Goodman, L. Soderholm, S.M. Mini, M. Ramanathan, G. K. Shenoy and A. S. Bommannavar, J.Phys. Condens, Matter 1, 6463 (1989).

  4. EUV, X-ray, and Gamma-ray instrumentation for astronomy; Proceedings of the Meeting, San Diego, CA, July 11-13, 1990

    SciTech Connect

    Siegmund, O.H.W.; Hudson, H.S. (California Univ., Berkeley (United States) California Univ., La Jolla (United States))

    1990-01-01

    Various papers on EUV, X-ray, and gamma-ray instrumentation for astronomy are presented. Individual topics addressed include: performance of lithium scatterers for X-ray polarimetry, shared X-ray concentration via crystal diffraction, optimum shields for spaceborne gamma-ray spectrometers, position-sensitive high-resolution spectrometer, IPCs for stellar X-ray polarimeter, soft X-ray windows for position-sensitive proportional counters, EUV imaging telescope array on the spectrum X-G satellite, European Photon Imaging Camera for X-ray astronomy, development of a UV auroral imager, background reduction in microchannel plates, 2D delay-line anode detector for astronomical imaging, dynamic range considerations for EUV MAMA detectors, Rosat WFD imaging detectors. Also discussed are: EUV band-pass filters for the Rosat wide-field camera, calibration of the Rosat High-Resolution Imager, superconducting tunneling junction detectors, test results of a prototype dielectric microcalorimeter, novel high-speed high-resolution position readout SPAN, after emission in microchannel plate detectors, highly curved microchannel plates, soft X-ray performance of back-illuminated EEV CCDs, proton damage effects in EEV CCDs, PN-CCDs for the XMM satellite mission, intensified CCD detectors using the phosphor TPB, silicon X-ray array detector concept, multilayer telescope for soft X-ray surveys, hard X-ray and soft gamma-ray astronomy mission EXOS.

  5. Structure of Amorphous Ferric Arsenate from EXAFS Spectroscopy and Total X-ray Scattering

    NASA Astrophysics Data System (ADS)

    Mikutta, Christian; Michel, Frederick Marc; Mandaliev, Petar; Kretzschmar, Ruben

    2013-04-01

    Short-range ordered ferric arsenate (FeAsO4 ×nH2O) is a secondary As mineral frequently encountered in acid mine-waste environments. Its structure has been proposed to resemble that of scorodite (FeAsO4×2H2O) in which isolated FeO6 octahedra share corners with four adjacent arsenate (AsO4) tetrahedra in a three-dimensional network (scorodite model). Conversely, short-range ordered ferric arsenate was postulated to consist of single chains of corner-sharing FeO6 octahedra being bridged by arsenate bound in a monodentate binuclear 2C complex (butlerite/fibroferrite model). In order to test the accuracy of both structural models, we synthesized ferric arsenates and analyzed their structure by As and Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy and total X-ray scattering. We found that both As and Fe K-edge EXAFS spectra were most compatible with isolated FeO6 octahedra being bridged by AsO4 tetrahedra (RFe-As= 3.33 ± 0.01 Å). EXAFS shell-fits and reduced pair distribution functions, G(r), indicated a lack of evidence for single corner-sharing FeO6 linkages in ferric arsenate. Wavelet-transform analyses of the Fe K-edge EXAFS spectra of ferric arsenates complemented by shell fitting confirmed Fe atoms at an average distance of 5.3 Å, consistent with crystallographic data of scorodite and in disagreement with the butlerite/fibroferrite model. A scorodite-type local structure of short-range ordered ferric arsenates provides a plausible explanation for their rapid transformation into scorodite in acid mining environments.

  6. Au36(SPh)24 nanomolecules: X-ray crystal structure, optical spectroscopy, electrochemistry, and theoretical analysis.

    PubMed

    Nimmala, Praneeth Reddy; Knoppe, Stefan; Jupally, Vijay Reddy; Delcamp, Jared H; Aikens, Christine M; Dass, Amala

    2014-12-11

    The physicochemical properties of gold:thiolate nanomolecules depend on their crystal structure and the capping ligands. The effects of protecting ligands on the crystal structure of the nanomolecules are of high interest in this area of research. Here we report the crystal structure of an all aromatic thiophenolate-capped Au36(SPh)24 nanomolecule, which has a face-centered cubic (fcc) core similar to other nanomolecules such as Au36(SPh-tBu)24 and Au36(SC5H9)24 with the same number of gold atoms and ligands. The results support the idea that a stable core remains intact even when the capping ligand is varied. We also correct our earlier assignment of "Au36(SPh)23" which was determined based on MALDI mass spectrometry which is more prone to fragmentation than ESI mass spectrometry. We show that ESI mass spectrometry gives the correct assignment of Au36(SPh)24, supporting the X-ray crystal structure. The electronic structure of the title compound was computed at different levels of theory (PBE, LDA, and LB94) using the coordinates extracted from the single crystal X-ray diffraction data. The optical and electrochemical properties were determined from experimental data using UV-vis spectroscopy, cyclic voltammetry, and differential pulse voltammetry. Au36(SPh)24 shows a broad electrochemical gap near 2 V, a desirable optical gap of ?1.75 eV for dye-sensitized solar cell applications, as well as appropriately positioned electrochemical potentials for many electrocatalytic reactions. PMID:25315687

  7. X-ray photoelectron spectroscopy and first principles calculation of BCN nanotubes.

    PubMed

    Kim, Shin Young; Park, Jeunghee; Choi, Hyun Chul; Ahn, Jae Pyung; Hou, Jin Qiang; Kang, Hong Seok

    2007-02-14

    Multiwalled boron carbonitride (BCN) nanotubes with two different structures were synthesized via thermal chemical vapor deposition; one has 10% C atoms homogeneously doped into BN nanotubes (B0.45C0.1N0.45 NTs), and the other has BN layers sheathed with 5-nm-thick C outerlayers (BN-C NTs). The electronic structures of the B, C, and N atoms were thoroughly probed by synchrotron X-ray photoelectron spectroscopy and the X-ray absorption near-edge structure method. The B0.45C0.1N0.45 NTs contain a significant amount of B-C and C-N bonding with a pyridine-like structure (hole structure), which reduces the pi bonding states of the B and N atoms. From the XPS valence band spectrum, the band gap was estimated to be about 2.8 eV. In the BN-C NTs, the C and BN domains are separated without forming the pyridine-like structure. Using the first principles method, we investigated the relative stabilities and electronic structures of the various isomers of the double-walled (12,0)@(20,0) BCN NTs. The C-outerlayer BN nanotube structure is the most stable isomer, when there exist no defects in the tubes with B/N = 1.0 (i.e., graphite-like structure). In addition, a reasonable model, which is characterized by the motives consisted of three pyridine-like rings around a hollow site, is presented for the local structure of C atoms in the B0.45N0.45C0.1 NTs. A considerable decrease of the band gap due to the 10% C doping was predicted, which was consistent with the experimental results. PMID:17243688

  8. Incorporation of arsenic in mammal bone: X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Kretschmer, X.; Pingitore, N. E.; Cruz-Jimenez, G.

    2002-12-01

    X-ray absorption spectroscopy (XAS) of the distal tibia of a modern deer, Odocoileus virginianus, revealed that the energy position of the As K edge matched that of a reference arsenic(V) model compound. Comparison of the x-ray absorption near edge structure (XANES) of the deer spectrum to the spectra of model As compounds indicated a close match to arsenate(V), e.g., zinc orthoarsenate(5). This indicates that the nearest-neighbor shell of the arsenic in the bone consists of four oxygens in the tetrahedral arrangement typical of arsenic(V) oxysalts. The XANES analysis demonstrates that the arsenic in the deer bone is not associated with an organic compound as a result of methylation. This suggests that the arsenic is associated with the mineral fraction of the bone, most likely with As substituting for P at the latter's structural site in the hydroxyapatite. The XAS data for the deer bone were very noisy due to the low level of arsenic present, just over 1 ppm.. A total of 18 scans, taking nearly a full 8-hour beam shift, were averaged to obtain the spectrum studied. It is not clear that the second neighbor shell can be characterized sufficiently from these data to confirm that As substitutes for P in hydroxyapatite. We conducted our XAS experiments on beam line 4-3 at the Stanford Synchrotron Radiation Laboratory. Data were collected in the fluorescence mode, using a solid state, 13-element Ge-detector. The energy reference was As(0) metal foil run parasitically in transmission mode during collection of the bone spectra. The edge shift seen in the experimental and As(V) model compound relative to the energy position of the arsenic(0) foil is consistent with the additional energy required to photoeject the 1-s electron of As(V), relative to that required for As(0). Arsenic content of the deer bone was determined by inductively coupled plasma mass spectrometry.

  9. Analysis of the Organic Content of Marine Aerosols with X-ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pham, D.; OBrien, R. E.; Fraund, M.; Laskina, O.; Alpert, P. A.; Prather, K. A.; Knopf, D. A.; Grassian, V. H.; Moffet, R.

    2014-12-01

    The ocean is a major global source of aerosols and the seawater from which they are derived is a complex mixture of organic molecules from organisms including phytoplankton, bacteria, and viruses. Marine aerosols consist of any combination of these components and in different mixing states. The mixing state affects absorption and scattering efficiency as well as their ability to uptake water and form ice. Therefore, there is a need to spatially resolve the chemical composition of individual marine aerosols in order to study their potential effects on the climate. Scanning Transmission X-ray Microscopy coupled with Near Edge X-ray Absorption Fine Structure spectroscopy (SXTM-NEXAFS) gives both spatial resolution as well as the sensitivity to molecular transitions that is necessary to correlate a position on an aerosol with a functional group or inorganic constituent. The morphology, mixing state, and chemical composition from STXM-NEXAFS can be used in conjunction with collocated measurements (light scattering, ice nucleation, etc.) to correlate the spatially resolved chemical composition of aerosols with their physical properties. The goal of this project is to determine if there is a difference in the organic fraction between particles with clearly different morphology and mixing states. Three major classes of marine aerosols have been classified as sea salt, marine gels, and cell fragments. Sea salt is classified by having an inorganic core consisting of NaCl and a thin layer of organic coating on the outside. Marine gels consist of organic material in the form of lipids, polysaccharides, and proteins distributed throughout the aerosol alongside inorganic compounds, such as Ca2+, Mg2+, and K+, that help to stabilize the negative charge of the organic material. Cell fragments include fragments from phytoplankton and bacteria. Efforts are currently underway to quantitatively evaluate differences in NEXAFS spectra for these particle types using nonlinear least squares.

  10. Dip Spectroscopy of the Low Mass X-Ray Binary XB 1254-690

    NASA Technical Reports Server (NTRS)

    Smale, Alan P.; Church, M. J.; BalucinskaChurch, M.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We observed the low mass X-ray binary XB 1254-690 with the Rossi X-ray Timing Explorer in 2001 May and December. During the first observation strong dipping on the 3.9-hr orbital period and a high degree of variability were observed, along with "shoulders" approx. 15% deep during extended intervals on each side of the main dips. The first observation also included pronounced flaring activity. The non-dip spectrum obtained using the PCA instrument was well-described by a two-component model consisting of a blackbody with kT = 1.30 +/- 0.10 keV plus a cut-off power law representation of Comptonized emission with power law photon index 1.10 +/- 0.46 and a cut-off energy of 5.9(sup +3.0, sub -1.4) keV. The intensity decrease in the shoulders of dipping is energy-independent, consistent with electron scattering in the outer ionized regions of the absorber. In deep dipping the depth of dipping reached 100%, in the energy band below 5 keV, indicating that all emitting regions were covered by absorber. Intensity-selected dip spectra were well-fit by a model in which the point-like blackbody is rapidly covered, while the extended Comptonized emission is progressively overlapped by the absorber, with the, covering fraction rising to 95% in the deepest portion of the dip. The intensity of this component in the dip spectra could be modeled by a combination of electron scattering and photoelectric absorption. Dipping did not occur during the 2001 December observation, but remarkably, both bursting and flaring were observed contemporaneously.

  11. Three New Galactic Center X-Ray Sources Identified with Near-infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    DeWitt, Curtis; Bandyopadhyay, Reba M.; Eikenberry, Stephen S.; Sellgren, Kris; Blum, Robert; Olsen, Knut; Bauer, Franz E.; Sarajedini, Ata

    2013-11-01

    We have conducted a near-infrared spectroscopic survey of 47 candidate counterparts to X-ray sources discovered by the Chandra X-Ray Observatory near the Galactic center (GC). Though a significant number of these astrometric matches are likely to be spurious, we sought out spectral characteristics of active stars and interacting binaries, such as hot, massive spectral types or emission lines, in order to corroborate the X-ray activity and certify the authenticity of the match. We present three new spectroscopic identifications, including a Be high-mass X-ray binary (HMXB) or a ? Cassiopeiae (Cas) system, a symbiotic X-ray binary, and an O-type star of unknown luminosity class. The Be HMXB/? Cas system and the symbiotic X-ray binary are the first of their classes to be spectroscopically identified in the GC region.

  12. Malayaite ceramic pigments: A combined optical spectroscopy and neutron/X-ray diffraction study

    SciTech Connect

    Cruciani, Giuseppe [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Dondi, Michele [ISTEC-CNR, Institute of Science and Technology for Ceramics, Via Granarolo 64, 48018 Faenza (Italy); Ardit, Matteo, E-mail: harditster@gmail.com [Department of Earth Sciences, University of Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Lyubenova, Teodora Stoyanova; Carda, Juan B. [Department of Inorganic and Organic Chemistry, University Jaime I, Campus Riu Sec, 12071 Castellon (Spain); Matteucci, Francesco; Costa, Anna L. [ISTEC-CNR, Institute of Science and Technology for Ceramics, Via Granarolo 64, 48018 Faenza (Italy)

    2009-08-05

    Ceramic pigments based on the Cr-doped malayaite structure were synthesized by solid state reaction and characterized by optical spectroscopy and combined X-ray and neutron powder diffraction in order to elucidate the still unclear chromium substitution mechanisms. The results show that coloration is actually due to simultaneous occurrence of Cr{sup 4+} and Cr{sup 3+} ions in the crystal lattice. Spectroscopy data confirm that Cr{sup 4+} is replacing Sn{sup 4+} in the octahedral site and, in minor amount, Si{sup 4+} in the tetrahedral site. In addition, neutron powder diffraction data suggest that Cr{sup 3+} substitution for octahedral Sn{sup 4+} is charge balanced by the formation of oxygen vacancies with no preference over the different oxygen sites. Upon incorporation of Cr ion, the SnO{sub 6} octahedra exhibit an off-centre displacement of central cation which in turn induces a rearrangement of both the octahedral and tetrahedral coordination shells.

  13. K? Mainline X-ray Emission Spectroscopy as an Experimental Probe of Metal–Ligand Covalency

    PubMed Central

    2015-01-01

    The mainline feature in metal K? X-ray emission spectroscopy (XES) has long been recognized as an experimental marker for the spin state of the metal center. However, even within a series of metal compounds with the same nominal oxidation and spin state, significant changes are observed that cannot be explained on the basis of overall spin. In this work, the origin of these effects is explored, both experimentally and theoretically, in order to develop the chemical information content of K? mainline XES. Ligand field expressions are derived that describe the behavior of K? mainlines for first row transition metals with any dn count, allowing for a detailed analysis of the factors governing mainline shape. Further, due to limitations associated with existing computational approaches, we have developed a new methodology for calculating K? mainlines using restricted active space configuration interaction (RAS–CI) calculations. This approach eliminates the need for empirical parameters and provides a powerful tool for investigating the effects that chemical environment exerts on the mainline spectra. On the basis of a detailed analysis of the intermediate and final states involved in these transitions, we confirm the known sensitivity of K? mainlines to metal spin state via the 3p–3d exchange coupling. Further, a quantitative relationship between the splitting of the K? mainline features and the metal–ligand covalency is established. Thus, this study furthers the quantitative electronic structural information that can be extracted from K? mainline spectroscopy. PMID:24914450

  14. [Characterization of biochar by X-ray photoelectron spectroscopy and 13C nuclear magnetic resonance].

    PubMed

    Xu, Dong-yu; Jin, Jie; Yan, Yu; Han, Lan-fang; Kang, Ming-jie; Wang, Zi-ying; Zhao, Ye; Sun, Ke

    2014-12-01

    The wood (willow branch) and grass (rice straw) materials were pyrolyzed at different temperatures (300, 450 and 600 °C) to obtain the biochars used in the present study. The biochars were characterized using elementary analysis, X-ray photoelectron spectroscopy (XPS) and solid state 13C cross-polarization and magic angle spinning nuclear magnetic resonance spectroscopy (13C NMR) to illuminate the structure and composition of the biochars which were derived from the different thermal temperatures and biomass. The results showed that the H/C, O/C and (O+N)/C ratios of the biochars decreased with the increase in the pyrolysis temperatures. The surface polarity and ash content of the grass-derived biochars were higher than those of the wood-derived biochars. The minerals of the wood-derived biochars were mainly covered by the organic matter; in contrast, parts of the mineral surfaces of the grass-derived biochars were not covered by organic matter? The 13C NMR of the low temperature-derived biochars revealed a large contribution of aromatic carbon, aliphatic carbon, carboxyl and carbonyl carbon, while the high temperature-derived biochars contained a large amount of aromatic carbon. Moreover, the wood-derived biochars produced at low heat treatment temperatures contained more lignin residues than grass-derived ones, probably due to the existence of high lignin content in the feedstock soures of wood-derived biochars. The results of the study would be useful for environmental application of biochars. PMID:25881450

  15. Soft X-ray synchrotron radiation spectroscopy study of molecule-based nanoparticles

    NASA Astrophysics Data System (ADS)

    Lee, Eunsook; Kim, D. H.; Kang, J.-S.; Kim, Kyung Hyun; Kim, Pil; Baik, Jaeyoon; Shin, H. J.

    2014-11-01

    The electronic structures of molecule-based nanoparticles, such as biomineralized Helicobacter pylori ferritin (Hpf), Heme, and RbCo[Fe(CN)6]H2O (RbCoFe) Prussian blue analogue, have been investigated by employing photoemission spectroscopy and soft X-ray absorption spectroscopy. Fe ions are found to be nearly trivalent in Hpf and Heme nanoparticles, which provides evidence that the amount of magnetite (Fe3O4) should be negligible in the Hpf core and that the biomineralization of Fe oxides in the high-Fe-bound-state Hpf core arises from a hematite-like formation. On the other hand, Fe ions are nearly divalent and Co ions are Co2+-Co3+ mixed-valent in RbCoFe. Therefore this finding suggests that the mechanism of the photo-induced transition in RbCoFe Prussian blue analogue is not a simple spin-state transition of Fe2+-Co3+ ? Fe3+-Co2+. It is likely that Co2+ ions have the high-spin configuration while Fe2+ ions have the low-spin configuration.

  16. X-ray photoelectron spectroscopy investigation of the incorporation of surface oxides into bulk zirconium

    SciTech Connect

    West, P.E.; George, P.M.

    1987-07-01

    X-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy have been used to investigate the mechanism by which a thin ZrO/sub 2/ film formed at the surface of polycrystalline zirconium dissolves into the bulk zirconium at 400/sup 0/C under nonoxidizing conditions. In addition to ZrO/sub 2/, a zirconium suboxide is directly observed in the XPS spectra taken after oxidation. On heating the oxidized Zr the intensity of both the Zr 3d/sub 5/2/ associated with ZrO/sub 2/ and the O 1s decay linearly with time. A concomitant linear increase is observed in the summed intensities of the Zr 3d/sub 5/2/ band associated with Zr metal and the suboxide Zr/sub x/O. A model is proposed to explain these observations which involves oxygen ion transport from the ZrO/sub 2/ to the metal interface where formation of a suboxide intermediate appears to be the rate-controlling step. The postulated suboxide at this temperature is Zr/sub x/O with x>1.

  17. Photoemission spectroscopy and X-ray diffraction analysis of 3D topological and Kondo insulators

    NASA Astrophysics Data System (ADS)

    Shibayev, Pavel

    2015-03-01

    The advantage of studying 3D topological insulators (TIs), compounds that have attracted the attention of many in the condensed matter field, is the ability for their existence at room temperature and no magnetic fields, allowing both for resolving their band structure via angle-resolved photoemission spectroscopy (ARPES) and understanding electrical transport and other properties via X-ray diffraction (XRD) and point-contact spectroscopy (PCS). A comprehensive quantitative analysis of Bi2Se3, a 3D TI, was carried out using these methods. The Bi2Se3\\ crystals were synthesized in-house at Princeton University. A first-principles calculation based on density functional theory, DFT, was performed using the Abinit software. The band structure of the crystal was then resolved via ARPES at the Advanced Light Source in LBNL, resulting in a surprisingly stark and clear single Dirac cone. A large band gap was confirmed, suggesting an increased potential for applications. In contrast, Kondo insulators are found in rare-earth based materials with f-electron degrees of freedom. Photon energy dependent dispersion relationships and temperature dependence studies were performed on a Kondo candidate CeB6 via ARPES, showing an even number of Dirac cones and a non-TI behavior. Analysis of I-V characteristics through PCS will follow, in addition to characterization via Bruker XRD for both compounds. Research group led by Professor M. Zahid Hasan (Princeton University).

  18. Nanoscale spectroscopy and tomography with the HZB X-ray microscope: Applications in materials and life sciences

    NASA Astrophysics Data System (ADS)

    Guttmann, P.; Rehbein, S.; Werner, S.; Henzler, K.; Tarek, B.; Schneider, G.

    2013-10-01

    The full-field transmission X-ray microscope at the electron storage ring BESSY II allows nanoscale spectroscopy as well as correlative fluorescence and nanoscale tomographic imaging of frozen-hydrated adherent cells. Reconstructions of tilt series permit the visualization of the sub-cellular structures in mammalian cells and plant cells. Quantitative information about package densities of cell organelles in the cytoplasm is possible. We present an overview of recent results in materials and life sciences obtained with the HZB X-ray microscope.

  19. Monitoring Long-Range Electron Transfer Pathways in Proteins by Stimulated Attosecond Broadband X-ray Raman Spectroscopy

    SciTech Connect

    Zhang, Yu; Biggs, Jason; Govind, Niranjan; Mukamel, Shaul

    2014-11-06

    Long-range electron transfer (ET) plays a key role in many biological energy conversion and synthesis processes. We show that nonlinear spectroscopy with attosecond X-ray pulses provides a real time movie of the evolving oxidation states and electron densities around atoms, and can probe these processes with high spatial and temporal resolution. This is demonstrated in a simulation study of the stimulated X-ray Raman (SXRS) signals in Re-modified azurin, which had long served as a benchmark for long-range ET in proteins. Nonlinear SXRS signals are sensitive to the local electronic structure and should offer a novel window for long-range ET.

  20. La-doped BaSnO3—Degenerate perovskite transparent conducting oxide: Evidence from synchrotron x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Sallis, S.; Scanlon, D. O.; Chae, S. C.; Quackenbush, N. F.; Fischer, D. A.; Woicik, J. C.; Guo, J.-H.; Cheong, S. W.; Piper, L. F. J.

    2013-07-01

    We report direct evidence of conduction band filling in 3% La-doped BaSnO3 using hard x-ray photoelectron spectroscopy. Direct comparisons with hybrid density functional theory calculations support a 3.2 eV indirect band gap. The use of hybrid DFT is verified by excellent agreement between our photoelectron spectra and O K-edge x-ray emission and absorption spectra. Our experimental and computational results demonstrate that the conduction band is primarily of Sn 5s orbital character with little O 2p contribution, which is a prerequisite for designing a perovskite-based transparent conducting oxide.

  1. Polarization Dependent X-ray Absorption Spectroscopy of the TiO2 Polymorphs Anatase (001) and Rutile (001)

    Microsoft Academic Search

    D. L. Ederer; N. Ruzycki; T. Schuler; G. P. Zhang; T. A. Callcott; P. Nachimuthu; R. C. C. Perera

    2002-01-01

    Polarization Dependent X-ray Absorption Spectroscopy of the TiO2 Polymorphs Anatase (001) and Rutile (001) N. Ruzycki^a, T. Schuler^a, D.L. Ederer^a, T. A. Callcott^, G. P. Zhang^b, P. Nachimuthu^c,d, and R.C.C. Perera^c a-Tulane University, Department of Physics, New Orleans, LA, 70118 b- Univesity of Tennessee, Department of Physics and Astronomy, Knoxville, TN, 37996 c- Center for X-ray Optics, Lawrence Berkeley Laboratory,

  2. Mechanical and Thermal Analysis of the Spectroscopy X-ray Telescopes for the Constellation-X Mission

    NASA Technical Reports Server (NTRS)

    Chan, Kai-Wing; Bolognese, Jeffrey; Saha, Timo; Sturm, James; Zhang, William

    2007-01-01

    Area and mass requirements for the Constellation-X Spectroscopy X-Ray Telescopes restrict the thickness of the mirror segment to below a mm. Requirement of angular resolution of 15" over the soft x-ray band implies that allowable optic deformation is sub-micrometer for these thin segments. These requirements place stringent constraint on the mounting, alignment and affixing of these mirror segments in both the metrology and integration processes. We present analyses and optimization of the Constellation-X mirrors under relevant mechanical and thermal environments.

  3. Soft X-ray microscopy and spectroscopy at the molecular environmental science beamline at the Advanced Light Source

    Microsoft Academic Search

    Hendrik Bluhm; Klas J. Andersson; Tohru Araki; Karim Benzerara; Gordon E. Brown; Jay J. Dynes; Sutapa Ghosal; Mary K. Gilles; Hans C. Hansen; J. C. Hemminger; Adam P. Hitchcock; Guido Ketteler; Arthur L. Kilcoyne; Eric M. Kneedler; John R. Lawrence; Gary G. Leppard; Juraj Majzlam; B. S. Mun; Satish C. Myneni; Anders R. Nilsson; Hirohito Ogasawara; D. F. Ogletree; Klaus H. Pecher; Miquel B. Salmeron; David K. Shuh; Brian Tonner; Tolek Tyliszczak; Tony Warwick; T. H. Yoon

    2006-01-01

    We present examples of the application of synchrotron-based spectroscopies and microscopies to environmentally relevant samples. The experiments were performed at the molecular environmental science beamline (11.0.2) at the Advanced Light Source, Lawrence Berkeley National Laboratory. Examples range from the study of water monolayers on Pt(111) single crystal surfaces using X-ray emission spectroscopy and the examination of alkali halide solution\\/water vapor

  4. Infrared and X-Ray Spectroscopy of the KES 75 Supernova Remnant Shell: Characterizing the Dust and Gas Properties

    NASA Technical Reports Server (NTRS)

    Temim, Tea; Dwek, Eli; Slane, Patrick; Arendt, Richard G.

    2009-01-01

    We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of 1.5 keV, or with two thermal components with temperatures of 1.5 and 0.2 keV. Previous studies suggest that the hot component may originate from reverse-shocked SN ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from supernova (SN) ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and ill emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the X-ray emitting gas. The IR spectrum of the shell is dominated by continuum emission from dust with little, or no line emission. Modeling the IR spectrum shows that the dust is heated to a temperature of 140 K by a relatively dense, hot plasma, that also gives rise to the hot X-ray emission component. The density inferred from the IR emission is significantly higher than the density inferred from the X-ray models, suggesting a low filling factor for this X-ray emitting gas. The total mass of the warm dust component is at least 1.3 x 10(exp -2) solar mass, assuming no significant dust destruction has occurred in the shell. The IR data also reveal the presence of an additional plasma component with a cooler temperature, consistent with the 0.2 keV gas component. Our IR analysis therefore provides an independent verification of the cooler component of the X-ray emission. The complementary analyses of the X-ray and IR emission provide quantitative estimates of density and filling factors of the clumpy medium swept up by the SNR.

  5. In situ extended x-ray absorption fine structure spectroscopy of thin-film nickel hydroxide electrodes

    SciTech Connect

    Capehart, T.W.; Corrigan, D.A.; Conell, R.S. (General Motors Research Laboratories, Warren, Michigan 48090 (US)); Pandya, K.I.; Hoffman, R.W. (Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106 (USA))

    1991-02-25

    A convenient {ital in} {ital situ} electrochemical cell has been developed which permits x-ray absorption measurements on thin-film electrodes under electrochemical polarization. Extended x-ray absorption fine structure spectra from highly disordered {alpha}-Ni(OH){sub 2} films, before and after polarization, provided quantitative results on the lattice contraction accompanying oxidation. Upon oxidation of {alpha}-Ni(OH){sub 2}, the Ni-O distance contracted from 2.05 to 1.86 A, and the Ni-Ni distance contracted from 3.09 to 2.82 A. The observed 10% contraction in the brucite plane is consistent with the 3.67 nickel valence in a K(NiO{sub 2}){sub 3} phase. The present technique extends x-ray absorption spectroscopy to the study of a variety of unstable materials not amenable to {ital ex} {ital situ} techniques.

  6. An in situ study using anomalous wide angle X-ray scattering and X-ray absorption spectroscopy of the binary metal oxide catalytic system SnO2-ZnAI2O4 supported on alumina

    Microsoft Academic Search

    R. Revel; D. Bazin; B. Bouchet-Fabre; A. Seigneurin; Y. Kihn

    2002-01-01

    A fine structural description of the local order around zinc and tin atoms of a binary metal oxide catalyst, namely SnO2-ZnAl2O4\\/AI2O3 which can be used as a DeNOx catalyst, is achieved through XAS (X-ray absorption Spectroscopy) and AWAXS (Anomalous wide angle X-ray scattering). The analysis of the data was supported by ab initio calculations based on the multiple scattering processes

  7. Local moments in iron-based superconductors probed with x-ray emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Kim, Young-June

    2014-03-01

    We report Fe K ? x-ray emission spectroscopy studies of local magnetic moments in various iron-based superconductors. X-ray emission spectroscopy (XES) is a fast, local probe that is bulk-sensitive and couples directly to the d-electron moment. Recently developed integrated absolute difference method of analyzing the XES signal allows us to study even small fluctuating moments found in metallic systems such as iron-based superconductors. In our survey of various materials in their paramagnetic phases, we found local magnetic moments in all samples studied: PrFeAsO, Ba(Fe,Co)2As2, LiFeAs, Fe1+x(Te,Se), and A2Fe4Se5 (where A = K, Rb, and Cs). The moment size shows very little dependence on temperature or carrier concentration, but varies significantly across different families. Specifically, all iron pnictide samples have local moments of about 1.5-2 ?B/Fe, while FeTe and K2Fe4Se5 families have much larger local moments of ?3 ?B/Fe and ?5 ?B/Fe, respectively. The extracted moment sizes agree well with energy and momentum integrated inelastic neutron scattering results. In addition, XES was used to study the spin-state transition in rare-earths doped CaFe2As2. When about 10-20% of Ca is replaced with Pr or Nd ions, this material goes through so-called collapsed tetragonal transition at 70 K, below which the c-lattice constant shrinks by almost 10%. The XES data show that the local magnetic moment is quenched in this collapsed tetragonal phase. We also found that the moment size exhibits unusually large temperature dependence even in the high temperature regime, indicating that the crystal field splitting and the Hund's rule coupling are of similar strength in this compound. Our experimental results illustrate the importance of multiorbital physics in describing magnetism of iron-based superconductors. Supported by NSERC, CFI, OMRI.

  8. Photon-in photon-out hard X-ray spectroscopy at the Linac Coherent Light Source

    PubMed Central

    Alonso-Mori, Roberto; Sokaras, Dimosthenis; Zhu, Diling; Kroll, Thomas; Chollet, Mathieu; Feng, Yiping; Glownia, James M.; Kern, Jan; Lemke, Henrik T.; Nordlund, Dennis; Robert, Aymeric; Sikorski, Marcin; Song, Sanghoon; Weng, Tsu-Chien; Bergmann, Uwe

    2015-01-01

    X-ray free-electron lasers (FELs) have opened unprecedented possibilities to study the structure and dynamics of matter at an atomic level and ultra-fast timescale. Many of the techniques routinely used at storage ring facilities are being adapted for experiments conducted at FELs. In order to take full advantage of these new sources several challenges have to be overcome. They are related to the very different source characteristics and its resulting impact on sample delivery, X-ray optics, X-ray detection and data acquisition. Here it is described how photon-in photon-out hard X-ray spectroscopy techniques can be applied to study the electronic structure and its dynamics of transition metal systems with ultra-bright and ultra-short FEL X-ray pulses. In particular, some of the experimental details that are different compared with synchrotron-based setups are discussed and illustrated by recent measurements performed at the Linac Coherent Light Source. PMID:25931076

  9. Surface studies of plastic-bonded PETN and RDX by X-Ray Photoelectron Spectroscopy (XPS) and Ion-Scattering Spectroscopy (ISS)

    Microsoft Academic Search

    P. S. Wang; W. E. Moddeman; L. D. Haws; T. N. Wittberg; J. A. Peters

    1981-01-01

    Surface structures of plastic bonded PETN and RDX were studied by high resolution X-Ray Photoelectron Spectroscopy (XPS) and Ion Scattering Spectroscopy (ISS). The coating material is a copolymer of vinyl chloride and chlorotrifluoroethylene. Specimens with 6 wt % of the coating on RDX and 4 wt % on PETN were used in these studies. High resolution elemented XPS spectra of

  10. Chemical analysis of plasma-polymerized films: The application of X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (NEXAFS) and fourier transform infrared spectroscopy (FTIR)

    Microsoft Academic Search

    I. Retzko; J. F. Friedrich; A. Lippitz; W. E. S. Unger

    2001-01-01

    Selected FTIR, XPS and NEXAFS spectroscopy results obtained with films deposited with different plasma polymerization processes and different monomers (styrene, acetylene, ethylene and butadiene) are presented. In detail FTIR spectra, XPS surveys, XPS valence bands and core level signals including shake-up features as well as carbon K-edge absorption spectra are qualitatively and, in some cases, semi-quantitatively considered. Information on the

  11. Time-resolved x-ray photoelectron spectroscopy techniques for real-time studies of interfacial charge transfer dynamics

    SciTech Connect

    Shavorskiy, Andrey; Hertlein, Marcus; Guo Jinghua; Tyliszczak, Tolek [Advanced Light Source, Lawrence Berkeley National Laboratory (United States); Cordones, Amy; Vura-Weis, Josh [Department of Chemistry, University of California Berkeley (United States); Siefermann, Katrin; Slaughter, Daniel; Sturm, Felix; Weise, Fabian; Khurmi, Champak; Belkacem, Ali; Weber, Thorsten; Gessner, Oliver [Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory (United States); Bluhm, Hendrik [Chemical Sciences Division, Lawrence Berkeley National Laboratory (United States); Strader, Matthew; Cho, Hana; Coslovich, Giacomo; Kaindl, Robert A. [Materials Sciences Division, Lawrence Berkeley National Laboratory (United States); Lin, Ming-Fu [Department of Chemistry, University of California Berkeley (United States); Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory (United States); and others

    2013-04-19

    X-ray based spectroscopy techniques are particularly well suited to gain access to local oxidation states and electronic dynamics in complex systems with atomic pinpoint accuracy. Traditionally, these techniques are applied in a quasi-static fashion that usually highlights the steady-state properties of a system rather than the fast dynamics that often define the system function on a molecular level. Novel x-ray spectroscopy techniques enabled by free electron lasers (FELs) and synchrotron based pump-probe schemes provide the opportunity to monitor intramolecular and interfacial charge transfer processes in real-time and with element and chemical specificity. Two complementary time-domain xray photoelectron spectroscopy techniques are presented that are applied at the Linac Coherent Light Source (LCLS) and the Advanced Light Source (ALS) to study charge transfer processes in N3 dye-sensitized ZnO semiconductor nanocrystals, which are at the heart of emerging light-harvesting technologies.

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

    E-print Network

    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 ...

  13. X-Ray Absorption Spectroscopy and EPR Studies of Oriented Spinach Thylakoid Preparations

    NASA Astrophysics Data System (ADS)

    Andrews, Joy Cooke

    1995-01-01

    In this study, oriented Photosystem II (PS II) particles from spinach chloroplasts are studied with electron paramagnetic resonance (EPR) and x-ray absorption spectroscopy (XAS) to determine more details of the structure of the oxygen evolving complex (OEC). The nature of halide binding to Mn is also studied with Cl K-edge and Mn EXAFS (extended x-ray absorption fine structure) of Mn-Cl model compounds, and with Mn EXAFS of oriented PS II in which Br has replaced Cl. In chapter 2, oriented PS II particles from spinach were studied with EPR spectroscopy. The mosaic spread for these samples was determined by comparison of the oxidized cytochrome b_{559} (cyt b_{559}^+) signal measured at angles of 0^circ to 360^circ between the EPR magnetic field and sample membrane normal with simulations of oriented cyt b_{559}^+. The tyrosine Y_{rm D }^+ signal was measured for these oriented samples at 0^circ and 90 ^circ, and a linear relationship was found between the dichroism found in the tyrosine Y _{rm D}^+ signal and the mosaic spread. In chapters 3 and 4, Mn XAS was performed on oriented PS II membrane particles isolated from spinach. Structural features of the tetranuclear Mn cluster and the orientation of the cluster with respect to the lipid bilayer were determined in the S_2 state of the Kok cycle for control samples, and on the annealed S_2 state for the ammonia-treated samples. Variation of the sample orientation with respect to the x-ray e-vector yields highly dichroic EXAFS, indicative of an asymmetric tetranuclear cluster. Mn-Mn vectors at 2.72 A and 3.3 A are resolved from the control samples. Vectors at 2.73 A, 2.86 A and 3.3 A are resolved from the ammonia-treated samples. The 2.72 A vector for the control samples is oriented at an angle of 59^circ to the membrane normal (an average for at least two component vectors) with an average of 0.98 interaction per Mn atom. In the ammonia-treated samples it is further resolved into a 2.73 A vector at 54^circ and a 2.85 A vector at 61^circ. Thus, asymmetry of the two di-mu-oxo bridged Mn-Mn binuclear units of the OEC is directly observed. In chapter 5, the binding of halide to Mn was studied using Cl K-edge XAS and Mn EXAFS on Mn-Cl model compounds, and Mn EXAFS on oriented Br-treated PS II. From the Cl K-edges of model compounds, direct ligation of Cl to Mn could be confirmed with the presence of a pre-edge feature: a forbidden 1s to 3d transition which is seen due to mixing of Mn 3d orbitals with Cl 3p orbitals. Bridging and terminal Cl bonds to Mn could be distinguished. EXAFS of Mn-Cl model compounds revealed that Mn-Cl interactions, especially bridging interactions, make an important contribution to the EXAFS. (Abstract shortened by UMI.).

  14. High-resolution x-ray spectroscopy of multicharged argon and krypton ions using a laser-produced x-ray source with a gas puff target

    Microsoft Academic Search

    Andrzej Bartnik; Vladimir M. Dyakin; Anatoly Y. Faenov; Henryk Fiedorowicz; Roman Jarocki; Joseph Nilsen; Albert L. Osterheld; Igor Y. Skobelev; Miroslaw Szczurek

    1997-01-01

    A hot and dense plasma can be produced by high-power laser irradiation of a high-pressure gas puff target. The plasma emits strong x-ray radiation in low photon-energy range (soft x-rays and XUV radiation) and is considered to be used as a debrisless laser-produced x-ray source. It was shown that the laser-irradiated gas puff plasma is an ideal source for the

  15. Probing reaction dynamics of transition-metal complexes in solution via time-resolved soft x-ray spectroscopy

    SciTech Connect

    Huse, N.; Kim, T.-K.; Khalil, M.; Jamula, L.; McCusker, J.K.; Schoenlein, R.W.

    2008-08-01

    We report the first time-resolved soft x-ray measurements of solvated transition-metal complexes. L-edge spectroscopy directly probes dynamic changes in ligand-field splitting of 3d orbitals associated with the spin transition, and mediated by changes in ligand-bonding. We report the first time-resolved soft x-ray spectroscopy of solution-phase molecular dynamics. Changes in ligand-field splitting and spin-state populations in 3d orbitals of the Fe{sup II} complex are directly probed via transient absorption changes of the Fe L{sub 2} and L{sub 3} edges following photo-induced metal-to-ligand charge transfer. With the emergence of high-flux ultrafast soft x-ray sources, details on interplay between atomic structure, electronic states, and spin contributions will be revealed. Our experimental approach opens the door to femtosecond soft x-ray investigations of liquid phase chemistry that have previously been inaccessible.

  16. Closing the pressure gap in x-ray photoelectron spectroscopy by membrane hydrogenation

    NASA Astrophysics Data System (ADS)

    Delmelle, Renaud; Probst, Benjamin; Alberto, Roger; Züttel, Andreas; Bleiner, Davide; Borgschulte, Andreas

    2015-05-01

    Comprehensive studies of gas-solid reactions require the in-situ interaction of the gas at a pressure beyond the operating pressure of ultrahigh vacuum (UHV) X-ray photoelectron spectroscopy (XPS). The recent progress of near ambient pressure XPS allows to dose gases to the sample up to a pressure of 20 mbar. The present work describes an alternative to this experimental challenge, with a focus on H2 as the interacting gas. Instead of exposing the sample under investigation to gaseous hydrogen, the sample is in contact with a hydrogen permeation membrane, through which hydrogen is transported from the outside to the sample as atomic hydrogen. Thereby, we can reach local hydrogen concentrations at the sample inside an UHV chamber, which is equipped with surface science tools, and this corresponds to a hydrogen pressure up to 1 bar without affecting the sensitivity or energy resolution of the spectrometer. This experimental approach is validated by two examples, that is, the reduction of a catalyst precursor for CO2 hydrogenation and the hydrogenation of a water reduction catalyst for photocatalytic H2 production, but it opens the possibility of the new in situ characterisation of energy materials and catalysts.

  17. Ultrafast x-ray photoelectron spectroscopy in the microsecond time domain

    NASA Astrophysics Data System (ADS)

    Höfert, O.; Gleichweit, C.; Steinrück, H.-P.; Papp, C.

    2013-09-01

    We introduce a new approach for ultrafast in situ high-resolution X-ray photoelectron spectroscopy (XPS) to study surface processes and reaction kinetics on the microsecond timescale. The main idea is to follow the intensity at a fixed binding energy using a commercial 7 channeltron electron analyzer with a modified signal processing setup. This concept allows for flexible switching between measuring conventional XP spectra and ultrafast XPS. The experimental modifications are described in detail. As an example, we present measurements for the adsorption and desorption of CO on Pt(111), performed at the synchrotron radiation facility BESSY II, with a time resolution of 500 ?s. Due to the ultrafast measurements, we are able to follow adsorption and desorption in situ at pressures of 2 × 10-6 mbar and temperatures up to 500 K. The data are consistently analyzed using a simple model in line with data obtained with conventional fast XPS at temperatures below 460 K. Technically, our new approach allows measurement on even shorter timescales, down to 20 ?s.

  18. Ultrafast x-ray photoelectron spectroscopy in the microsecond time domain.

    PubMed

    Höfert, O; Gleichweit, C; Steinrück, H-P; Papp, C

    2013-09-01

    We introduce a new approach for ultrafast in situ high-resolution X-ray photoelectron spectroscopy (XPS) to study surface processes and reaction kinetics on the microsecond timescale. The main idea is to follow the intensity at a fixed binding energy using a commercial 7 channeltron electron analyzer with a modified signal processing setup. This concept allows for flexible switching between measuring conventional XP spectra and ultrafast XPS. The experimental modifications are described in detail. As an example, we present measurements for the adsorption and desorption of CO on Pt(111), performed at the synchrotron radiation facility BESSY II, with a time resolution of 500 ?s. Due to the ultrafast measurements, we are able to follow adsorption and desorption in situ at pressures of 2 × 10(-6) mbar and temperatures up to 500 K. The data are consistently analyzed using a simple model in line with data obtained with conventional fast XPS at temperatures below 460 K. Technically, our new approach allows measurement on even shorter timescales, down to 20 ?s. PMID:24089812

  19. X-ray Emission Spectroscopy Evidences a Central Carbon in the Nitrogenase Iron-Molybdenum Cofactor

    PubMed Central

    Lancaster, Kyle M.; Roemelt, Michael; Ettenhuber, Patrick; Hu, Yilin; Ribbe, Markus W.; Neese, Frank; Bergmann, Uwe; DeBeer, Serena

    2013-01-01

    One Sentence Summary The central light atom in the iron-molybdenum cofactor of nitrogenase is identified as carbon. Nitrogenase is a complex enzyme that catalyzes the reduction of dinitrogen to ammonia. Despite insight from structural and biochemical studies, its structure and mechanism await full characterization. An iron-molybdenum cofactor (FeMoco) is thought to be the site of dinitrogen reduction, but the identity of a central atom in this cofactor remains unknown. Fe Kß X-ray emission spectroscopy (XES) of intact nitrogenase MoFe protein, isolated FeMoco, and the FeMoco-deficient ?nifB protein indicates that among the candidate atoms O, N, and C, it is C that best fits the XES data. The experimental XES is supported by computational efforts, which shows that oxidation and spin states do not affect the assignment of the central atom to C4-. Identification of the central atom will drive further studies on its role in catalysis. PMID:22096198

  20. Depth-profiling X-ray photoelectron spectroscopy (XPS) analysis of interlayer diffusion in polyelectrolyte multilayers

    PubMed Central

    Gilbert, Jonathan B.; Rubner, Michael F.; Cohen, Robert E.

    2013-01-01

    Functional organic thin films often demand precise control over the nanometer-level structure. Interlayer diffusion of materials may destroy this precise structure; therefore, a better understanding of when interlayer diffusion occurs and how to control it is needed. X-ray photoelectron spectroscopy paired with C60+ cluster ion sputtering enables high-resolution analysis of the atomic composition and chemical state of organic thin films with depth. Using this technique, we explore issues common to the polyelectrolyte multilayer field, such as the competition between hydrogen bonding and electrostatic interactions in multilayers, blocking interlayer diffusion of polymers, the exchange of film components with a surrounding solution, and the extent and kinetics of interlayer diffusion. The diffusion coefficient of chitosan (M = ?100 kDa) in swollen hydrogen-bonded poly(ethylene oxide)/poly(acrylic acid) multilayer films was examined and determined to be 1.4*10?12 cm2/s. Using the high-resolution data, we show that upon chitosan diffusion into the hydrogen-bonded region, poly(ethylene oxide) is displaced from the film. Under the conditions tested, a single layer of poly(allylamine hydrochloride) completely stops chitosan diffusion. We expect our results to enhance the understanding of how to control polyelectrolyte multilayer structure, what chemical compositional changes occur with diffusion, and under what conditions polymers in the film exchange with the solution. PMID:23569265

  1. X-ray Absorption Spectroscopy of the Multi-phase Interstellar Medium: Oxygen and Neon Abundances

    E-print Network

    Yao, Y; Yao, Yangsen

    2006-01-01

    X-ray absorption spectroscopy provides a potentially powerful tool in determining the metal abundances in various phases of the interstellar medium (ISM). We present a case study of the sight line toward 4U 1820-303 (Galactic coordinates l, b=2.79, -7.91 and distance = 7.6 kpc), based on Chandra Grating observations. The detection of OI, OII, OIII, OVII, OVIII, and NeIX Kalpha absorption lines allows us to measure the atomic column densities of the neutral, warm ionized, and hot phases of the ISM through much of the Galactic disk. By comparing these measurements with the 21 cm hydrogen emission and with the pulsar dispersion measure along the same sight line, we estimate the mean oxygen abundances in the neutral and total ionized phases as 0.3(0.2, 0.6) and 2.2(1.1, 3.5) in units of Anders & Grevesse (1989) solar value. This significant oxygen abundance difference is apparently a result of molecule/dust grain destruction and recent metal enrichment in the warm ionized and hot phases. We also measure the c...

  2. Hydrazine reduction of transition metal oxides - In situ characterization using X-ray photoelectron spectroscopy

    NASA Technical Reports Server (NTRS)

    Littrell, D. M.; Tatarchuk, B. J.

    1986-01-01

    The transition metal oxides (TMOs) V2O5, FeO3, Co3O4, NiO, CuO, and ZnO were exposed to hydrazine at various pressures. The metallic surfaces were surveyed by in situ X-ray photoelectron spectroscopy to determine the irrelative rate of reduction by hydrazine. The most easily reducible oxide, CuO, could be reduced to the metallic state at room temperature and 10 to the -6th torr. The reaction is first order with respect to CuO, with an activation energy of about 35 kJ/mol. Two types of adsorption were seen to occur at 295 K: (1) a reversible component in which the measured N:Cu ratio increased to 0.60 at hydrazine pressures up to 0.5 torr, and (2) an irreversible component, with a N:Cu ratio of 0.28, which could not be removed by extended vacuum pumping. The results of this study are useful for the identification of TMO's that can be used as solid neatallizers of hydrazine spills, and for the preparation of metal surfaces for electroplating and evaporative thin-film coating.

  3. Oxidation-state analysis of ceria by X-ray photoelectron spectroscopy.

    PubMed

    Allahgholi, Aschkan; Flege, J Ingo; Thieß, Sebastian; Drube, Wolfgang; Falta, Jens

    2015-04-01

    Three different methods to determine the oxide-phase concentration in mixed cerium oxide by hard X-ray photoelectron spectroscopy are applied and quantitatively compared. Synchrotron-based characterization of the O?1s region was used as a benchmark to introduce a method based on the weighted superposition of the Ce?3d spectra of the pure Ce(3+) and Ce(4+) phases, which was shown to lead to reliable and highly accurate determination of the mean oxidation state in mixed cerium oxides. The results obtained reveal a linear relation between the third distinct final state (u''') satellite peak intensity of the Ce(4+) phase and the Ce(4+) concentration by proper inclusion of Ce(3+)-related plasmon satellite peaks, which contradicts previous claims of nonlinear behavior. In contrast, quantitative conventional peak-fitting procedures were shown to be well suited for the Ce?2p region due to its relatively simple structure. Additional satellite features observed in the Ce?3d spectrum of CeO2 were proposed to originate from plasmon contributions. PMID:25703923

  4. Soft X-ray Spectroscopy for Understanding the Cycling Mechanism of Novel Lithium-ion Batteries

    NASA Astrophysics Data System (ADS)

    Qiao, Ruimin; Kostecki, Robert; Lucas, Ivan; Persson, Kristin; Chen, Wei; Li, Hong; Wang, Rui; Yang, Wanli

    2014-03-01

    Energy and environment are two major concerns of the modern world. Transition to the sustainable clean energy globally in the future, however, depends on the development of next generation electrical energy storage systems. Among the energy storage techniques considered at present, rechargeable lithium-ion batteries, which are ubiquitous in today's portable electronic devices and now enable the electric vehicles, remain promising to facilitate the use of renewable energy on a large scale. For such application, transformational changes in battery technologies are critically needed, which require a fundamental understanding of the complex, interrelated physical and chemical processes between electrode materials and electrolytes Soft x-ray absorption spectroscopy(sXAS) is a powerful tool to probe the chemical species and the electronic states with elemental sensitivity. This presentation will discuss examples on using sXAS to study battery materials for both fundamental understanding and practical developments. We will showcase how sXAS fingerprints the battery operation by detecting the evolving electron states. Recent results on SEIs and Li-rich cathode materials will be discussed. Our results offer important information for improving Li batteries.

  5. X-ray absorption spectroscopy of biomimetic dye molecules for solar cells

    NASA Astrophysics Data System (ADS)

    Cook, Peter L.; Liu, Xiaosong; Yang, Wanli; Himpsel, F. J.

    2009-11-01

    Dye-sensitized solar cells are potentially inexpensive alternatives to traditional semiconductor solar cells. In order to optimize dyes for solar cells we systematically investigate the electronic structure of a variety of porphyrins and phthalocyanines. As a biological model system we use the heme group in cytochrome c which plays a role in biological charge transfer processes. X-ray absorption spectroscopy of the N 1s and C 1s edges reveals the unoccupied molecular orbitals and the orientation of the molecules in thin films. The transition metal 2p edges reflect the oxidation state of the central metal atom, its spin state, and the ligand field of the surrounding N atoms. The latter allows tuning of the energy position of the lowest unoccupied orbital by several tenths of an eV by tailoring the molecules and their deposition. Fe and Mn containing phthalocyanines oxidize easily from +2 to +3 in air and require vacuum deposition for obtaining a reproducible oxidation state. Chlorinated porphyrins, on the other hand, are reduced from +3 to +2 during vacuum deposition at elevated temperatures. These findings stress the importance of controlled thin film deposition for obtaining photovoltaic devices with an optimum match between the energy levels of the dye and those of the donor and acceptor electrodes, together with a molecular orientation for optimal overlap between the ? orbitals in the direction of the carrier transport.

  6. Electronic structure of advanced materials studied by x-ray emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Kurmaev, E. Z.; Galakhov, V. R.; Yarmoshenko, Yu. M.; Trofimova, V. A.; Shamin, S. N.; Cherkashenko, V. M.; Poteryaev, A. I.; Anisimov, V. I.

    1997-01-01

    High resolution soft x-ray emission spectroscopy with high spatial resolution is used to study of the electronic structure and characterize advanced materials: high-Tc superconductors, transition metal compounds, porous silicon, solid-solid buried interfaces and hard materials. In high-Tc, the main attention is focused on the analysis of oxygen-cation interactions and the determination of the location of impurity atoms. In transition metal compounds the participation of different electronic states of constitute atoms in the valence band is analyzed and correctness of LDA band structure calculations is estimated. For CuFeO2 an unusual mutual position of the Cu3d and Fe3d bands was found which is attributed to strong electron-electron correlations. In porous silicon the local structure of silicon atoms is found to depend on the type of doping of the initial Si wafer. Solid-solid buried interfaces in thin semiconducting films irradiated by eximer laser are investigated. For the hard materials boron-carbonitride a structure consisting of hexagonal lattice planes of carbon and boron nitride is proposed.

  7. Wettability of silane-treated glass slides as determined from X-ray photoelectron spectroscopy

    SciTech Connect

    Araujo, Y.C.; Toledo, P.G.; Leon, V.; Gonzalez, H.Y. [INTEVEP, S.A., Caracas (Venezuela). Research and Technological Support Center of Petroleos de Venezuela] [INTEVEP, S.A., Caracas (Venezuela). Research and Technological Support Center of Petroleos de Venezuela

    1995-12-15

    The wettability and stability of silane-treated substrates are central in many processes of industrial and environmental interest. Here, the authors bring the capability of X-ray photoelectron spectroscopy (XPS) to bear on the wettability evaluation of treated glass. For a suite of silane-treated slides the authors investigate the relationship between wettability and surface composition as determined from XPS. The adhesion behavior and contact angle of mineral oil on brine-covered surfaces are used here as surface wettability indicators. The XPS spectra of silanes and silane-treated glass slides indicate that silicon species of the kind Si-CH exhibit a well-defined binding energy which differs from that of the Si-O species of the glass. The presence of the Si-CH species reveals glass surfaces that have been rendered hydrophobic by chemisorption of organic matter. The surface carbon content as determined from XPS correlates strongly with the equilibrium contact angle, contact angle hysteresis, adhesion behavior, and wettability state. This correlation can be used to rapidly determine the wettability of treated glass.

  8. Transient X-ray absorption spectroscopy as a probe of catalyst kinetics during butane oxidation

    SciTech Connect

    Coulston, G.W. [DuPont Co., Wilmington, DE (United States)

    1996-12-31

    Alkanes are attractive alternatives to alkenes and aromatics as feedstocks for production of specialty chemicals, particularly for synthesis of oxygenates. However, the requisite energy needed for activation of the first C-H bond is usually enough to ensure that the reaction proceeds completely to carbon dioxide and water. One exceptional reaction is the oxidation of n-butane to maleic anhydride using a vanadium pyrophosphate catalyst. Since its discovery more than 20 years ago, this system has received a great deal of attention from the catalysis community; primarily because of hopes that structure-performance relationships derived for the VPO system would lead to development of catalysts for other alkane oxidations. In spite of this interest, many basic questions remain unanswered. For example, it has long been known that lattice oxygen (as opposed to adsorbed oxygen) plays an important role in the mechanism of butane oxidation, but the particular states of vanadium involved remain unknown. This presentation will focus on how we are using in situ time resolved dispersive X-ray absorption spectroscopy to address this question for both supported and unsupported vanadium phosphate catalysts.

  9. Local structures of methanol-water binary solutions studied by soft X-ray absorption spectroscopy.

    PubMed

    Nagasaka, Masanari; Mochizuki, Kenji; Leloup, Valentin; Kosugi, Nobuhiro

    2014-04-24

    Liquid methanol shows one- and two-dimensional (1D/2D) hydrogen bond (HB) networks, and liquid water shows three-dimensional (3D) HB networks. We have clearly found three different local structures around the methyl group of methanol-water binary solutions (CH3OH)X(H2O)1-X at different concentrations in C K-edge soft X-ray absorption spectroscopy (XAS). With the help of molecular dynamics simulations, we have discussed the concentration dependence of the hydrophobic interaction at the methyl group in the C K-edge XAS spectra. In the methanol-rich region I (1.0 > X > 0.7), a small amount of water molecules exists separately around dominant 1D/2D HB networks of methanol clusters. In the region II (0.7 > X > 0.3), the hydrophobic interaction of the methyl group is dominant due to the increase of mixed methanol-water 3D network structures. In the water-rich region III (0.3 > X > 0.05), methanol molecules are separately embedded in dominant 3D HB networks of water. On the other hand, the pre-edge feature in the O K-edge XAS shows almost linear concentration dependence. It means the HB interaction between methanol and water is almost the same as that of water-water and of methanol-methanol. PMID:24694018

  10. Rapid preparation of RNA samples for NMR spectroscopy and X-ray crystallography

    PubMed Central

    Cheong, Hae-Kap; Hwang, Eunha; Lee, Chulhyun; Choi, Byong-Seok; Cheong, Chaejoon

    2004-01-01

    Knowledge of the three-dimensional structures of RNA and its complexes is important for understanding the molecular mechanism of RNA recognition by proteins or ligands. Enzymatic synthesis using T7 bacteriophage RNA polymerase is used to prepare samples for NMR spectroscopy and X-ray crystallography. However, this run-off transcription method results in heterogeneity at the RNA 3-terminus. For structural studies, RNA purification requires a single nucleotide resolution. Usually PAGE purification is used, but it is tedious, time-consuming and cost ineffective. To overcome these problems in high-throughput RNA synthesis, we devised a method of RNA preparation that uses trans-acting DNAzyme and sequence-specific affinity column chromatography. A tag sequence is added at the 3? end of RNA, and the tagged RNA is picked out using an affinity column that contains the complementary DNA sequence. The 3? end tag is then removed by sequence-specific cleavage using trans-acting DNAzyme, the arm lengths of which are optimized for turnover number. This purification method is simpler and faster than the conventional method. PMID:15199176

  11. X-Ray Photoelectron Spectroscopy and Tribology Studies of Annealed Fullerene-like WS2 Nanoparticles

    NASA Astrophysics Data System (ADS)

    Kopnov, F.; Tenne, R.; Späth, B.; Jägermann, W.; Cohen, H.; Feldman, Y.; Zak, A.; Moshkovich, A.; Rapoport, L.

    The temporal chemical changes occurring at the surface of fullerene-like (IF) nanoparticles of WS2 were investigated using X-ray photo-electron spectroscopy (XPS) and compared to those of bulk powder (2H) of the same material. It is possible to follow the long term (surface oxidation and carbonization) occurring at defects on the outermost surface (0001) layer of the fullerene-like nanoparticles. Similar but perhaps more distinctive changes are observed on the prismatic (hk0) surfaces of the 2H powder. Vacuum annealing is shown to remove most of these changes and bring the surface close to its stoichiometric composition. In accordance with previous measurements, further evidence is obtained for the existence of water molecules which are entrapped in the hollow core and interstitial defects of the fullerene-like nanoparticles during the synthesis. They are also shown to be removed by the vacuum annealing process. Chemically resolved electrical measurements (CREM) in the XPS show that the vacuum annealed IF samples become more intrinsic. Finally, tribological measurements show that the vacuum annealed IF samples perform better as an additive to oil than the non-annealed IF samples and the bulk (2H) platelets powder.

  12. Mössbauer spectroscopy of europium-containing glasses: Optical activator study for x-ray image plates

    PubMed Central

    Johnson, C.E.; Vu, M.; Johnson, J.A.; Brown, D.E.; Weber, J.K.R.; Paßlick, C.; Schweizer, S.

    2014-01-01

    A fluorozirconate glass (ZBLAN) containing BaCl2 nanocrystals doped with divalent Eu is a promising material for x-ray image plates for medical diagnosis. Since it is known that Eu2+ readily oxidizes to Eu3+, which reduces fluorescence efficiency of the image plates, 151Eu Mössbauer spectroscopy was used in this work to monitor the Eu oxidation state of the samples during degradation over time in the presence of ambient humidity. In addition, Mössbauer spectroscopic experiments show that the oxidation state has already changed during the glass melt: The sample made from 5 mol% EuCl2 contained 78% EuCl2 + 22% EuCl3 deduced from the relative areas of the absorption lines. The sample made from 2.5 mol% EuCl2 + 2.5 mol% EuCl2 contained 37% EuCl2 + 63% EuCl3, i.e. 26% of the original EuCl2 was oxidized to EuCl3. PMID:24839344

  13. X-ray absorption spectroscopy of biomimetic dye molecules for solar cells

    SciTech Connect

    Cook, Peter L.; Liu Xiaosong; Himpsel, F. J. [Department of Physics, University of Wisconsin Madison, 1150 University Ave., Madison, Wisconsin 53706 (United States); Yang Wanli [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2009-11-21

    Dye-sensitized solar cells are potentially inexpensive alternatives to traditional semiconductor solar cells. In order to optimize dyes for solar cells we systematically investigate the electronic structure of a variety of porphyrins and phthalocyanines. As a biological model system we use the heme group in cytochrome c which plays a role in biological charge transfer processes. X-ray absorption spectroscopy of the N 1s and C 1s edges reveals the unoccupied molecular orbitals and the orientation of the molecules in thin films. The transition metal 2p edges reflect the oxidation state of the central metal atom, its spin state, and the ligand field of the surrounding N atoms. The latter allows tuning of the energy position of the lowest unoccupied orbital by several tenths of an eV by tailoring the molecules and their deposition. Fe and Mn containing phthalocyanines oxidize easily from +2 to +3 in air and require vacuum deposition for obtaining a reproducible oxidation state. Chlorinated porphyrins, on the other hand, are reduced from +3 to +2 during vacuum deposition at elevated temperatures. These findings stress the importance of controlled thin film deposition for obtaining photovoltaic devices with an optimum match between the energy levels of the dye and those of the donor and acceptor electrodes, together with a molecular orientation for optimal overlap between the {pi} orbitals in the direction of the carrier transport.

  14. Closing the pressure gap in x-ray photoelectron spectroscopy by membrane hydrogenation.

    PubMed

    Delmelle, Renaud; Probst, Benjamin; Alberto, Roger; Züttel, Andreas; Bleiner, Davide; Borgschulte, Andreas

    2015-05-01

    Comprehensive studies of gas-solid reactions require the in-situ interaction of the gas at a pressure beyond the operating pressure of ultrahigh vacuum (UHV) X-ray photoelectron spectroscopy (XPS). The recent progress of near ambient pressure XPS allows to dose gases to the sample up to a pressure of 20 mbar. The present work describes an alternative to this experimental challenge, with a focus on H2 as the interacting gas. Instead of exposing the sample under investigation to gaseous hydrogen, the sample is in contact with a hydrogen permeation membrane, through which hydrogen is transported from the outside to the sample as atomic hydrogen. Thereby, we can reach local hydrogen concentrations at the sample inside an UHV chamber, which is equipped with surface science tools, and this corresponds to a hydrogen pressure up to 1 bar without affecting the sensitivity or energy resolution of the spectrometer. This experimental approach is validated by two examples, that is, the reduction of a catalyst precursor for CO2 hydrogenation and the hydrogenation of a water reduction catalyst for photocatalytic H2 production, but it opens the possibility of the new in situ characterisation of energy materials and catalysts. PMID:26026511

  15. Investigation of the surface composition of electrodeposited black chromium by X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Survilien?, S.; ?eš?nien?, A.; Jasulaitien?, V.; Jurevi?i?t?, I.

    2015-01-01

    The paper reviews black chromium electrodeposited from a trivalent chromium bath containing ZnO as a second main component. The chemical compositions of the top layers of the black chromium coatings were studied by the X-ray photoelectron spectroscopy method. The surface of black chromium was found to be almost entirely covered with organic substances. To gain information on the state of each element in the deposit bulk, the layer-by-layer etching of the black chromium surface with argon gas was used. Analysis of XPS spectra has shown that the top layers of black chromium without zinc are composed of various Cr(III) components, organic substances and metallic Cr, whereas metallic Cr is almost absent in black chromium containing some amount of Zn(II) compounds. The ratios of metal/oxide phases were found to be 10/27 and 2/28 for black chromium without and with zinc, respectively. It has been determined that owing to the presence of ZnO in the Cr(III) bath, the percentage of metallic chromium is substantially reduced in black chromium which is quite important for good solar selective characteristics of the coating. The results confirm some of earlier observations and provide new information on the composition of the near-surface layers.

  16. X-ray absorption spectroscopy studies of electrochemically deposited thin oxide films

    SciTech Connect

    Balasubramanian, M.; Melendres, C.A. [Argonne National Lab., IL (United States); Mansour, A.N. [Naval Surface Warfare Center, West Bethesda, MD (United States); Mini, S. [Northern Illinois Univ., DeKalb, IL (United States)

    1998-12-31

    Radioactive contamination of piping systems and storage tanks generally emanates from radionuclides that have been incorporated into corrosion products and scale deposits that coat the surface of the metal alloys which constitute the materials of construction of the pipes and tanks. Knowledge of both the local structure of the corrosion scales by itself and that of the heavy metal ions that are incorporated into the corrosion scales is essential in developing cost-effective clean-up processes via chemical and electrochemical methods. The authors have utilized in situ X-ray Absorption Fine Structure Spectroscopy to investigate the structure and composition of thin oxide films of nickel and iron that have been prepared by electrodeposition on a graphite substrate from aqueous solutions. The films are generally disordered. Structural information has been obtained form the analysis of the data. They also present initial findings on the local structure of heavy metal ions, e.g. Sr and Ce, incorporated into the electrodeposited nickel oxide films. Their results are of importance in a number of technological applications, among them, batteries, fuel cells, electrochromic and ferroelectric materials, corrosion protection, as well as environmental speciation and remediation.

  17. CHARACTERIZING SURFACE LAYERS IN NITINOL USING X-RAY PHOTOELECTRON SPECTROSCOPY

    SciTech Connect

    Christopfel, R.; Mehta, A.

    2008-01-01

    Nitinol is a shape memory alloy whose properties allow for large reversible deformations and a return to its original geometry. This nickel-titanium (NiTi) alloy has become a material used widely in the biomedical fi eld as a stent to open up collapsed arteries. Both ambient and biological conditions cause surface oxidation in these devices which in turn change its biocompatibility. The thickness of oxidized layers can cause fractures in the material if too large and can allow for penetration if too thin. Depending on the type and abundance of the chemical species on or near the surface, highly toxic metal ions can leak into the body causing cell damage or even cell death. Thus, biocompatibility of such devices is crucial. By using highly surface sensitive x-ray photoelectron spectroscopy to probe the surface of these structures, it is possible to decipher both layer composition and layer thickness. Two samples, both of which were mechanically polished, were investigated. Of the two samples, one was then exposed to a phosphate buffered saline (PBS) solution to mimic the chemical properties of blood, while the other remained unexposed. Although both samples were found to have oxide layers of appropriate thickness (on the order of a few nm), it was found that the sample exposed to the saline solution had a slightly thicker oxide layer and more signifi cantly, a phosphate layer very near the surface suggesting toxic metal components are well contained within the sample. These are considerable indications of a biocompatible device.

  18. X-ray photoelectron spectroscopy surface analysis of aluminum ion stress in barley roots. [Hordeum vulgare

    SciTech Connect

    Millard, M.M.; Foy, C.D.; Coradetti, C.A.; Reinsel, M.D. (Department of Agriculture, Beltsville, MD (USA))

    1990-06-01

    X-ray photoelectron spectroscopy (XPS) has been used to analyze root surface changes when Dayton barley (Hordeum vulgare) (Al tolerant) and Kearney barley (Al sensitive) seedlings were grown in nutrient solution in the presence and absence of 37.0 micromolar Al. The electron spectra from root surfaces contained strong lines in order of decreasing intensity from organic forms of carbon, oxygen, and nitrogen and weak lines due to inorganic elements in the form of anions and cations on the surface. The surface composition of root tips from Kearney was C, 65.6%; 0, 26.8%; N, 4.4% and tips from Dayton was C, 72.7%; O, 23.6%; N, 1.9%, grown in the absence of aluminum. Electron lines characteristic of nitrate, potassium, chloride, phosphate were also present in the spectra from those roots. Dayton roots grown in the presence of 37.0 micromolar aluminum contained 2.1% aluminum while Kearney contained 1.3% aluminum. The ratio of aluminum to phosphate was close to 1.0. Dayton roots usually contained twice as much aluminum phosphate in the surface region as Kearney. Dayton may be less susceptible to Al toxic effects by accumulation of aluminum phosphate on the root surface which then acts as a barrier to the transport of aluminum into the interior of the roots.

  19. X-ray absorption spectroscopy investigation of the activation process of Raney nickel catalysts

    SciTech Connect

    Rothe, J.; Hormes, J.; Schild, C.; Pennemann, B.

    2000-04-25

    Raney Nickel catalysts have found widespread application in the field of the hydrogenation of organic compounds, especially as anodes in liquid fuel cells. The formation of highly reactive Raney Nickel catalysts, which are commonly used in hydrogenation reactions, has been studied using X-ray absorption spectroscopy (XAS) with synchrotron radiation. Various samples representing different frozen states of the activation reaction have been prepared. The process has been quenched after different reaction times by neutralizing the alkaline solution leaching the aluminum from the two alloys used as educts. XANES spectra taken at the Ni K edge of the catalysts derived from an Ni/Al alloy and an Ni/Al/Fe alloy reveal that the transformation starts with a very rapid change of the electronic structure followed by a much slower change of the geometric structure of the alloys. Most noticeable is the sharp increase of the density of empty d band states, which partially redevelop when the reaction products slowly relax to an electronic as well as a lattice structure similar to that of fcc-Ni metal. Thus at least a well-defined local order is preserved in the final catalysts. The presence of Fe (6 wt%) in the starting alloy slows down the reaction, while the Fe K-XANES points to the oxidation of this component.

  20. In Situ Ambient Pressure X-ray Photoelectron Spectroscopy Studies of Lithium-Oxygen Redox Reactions

    PubMed Central

    Lu, Yi-Chun; Crumlin, Ethan J.; Veith, Gabriel M.; Harding, Jonathon R.; Mutoro, Eva; Baggetto, Loïc; Dudney, Nancy J.; Liu, Zhi; Shao-Horn, Yang

    2012-01-01

    The lack of fundamental understanding of the oxygen reduction and oxygen evolution in nonaqueous electrolytes significantly hinders the development of rechargeable lithium-air batteries. Here we employ a solid-state Li4+xTi5O12/LiPON/LixV2O5 cell and examine in situ the chemistry of Li-O2 reaction products on LixV2O5 as a function of applied voltage under ultra high vacuum (UHV) and at 500 mtorr of oxygen pressure using ambient pressure X-ray photoelectron spectroscopy (APXPS). Under UHV, lithium intercalated into LixV2O5 while molecular oxygen was reduced to form lithium peroxide on LixV2O5 in the presence of oxygen upon discharge. Interestingly, the oxidation of Li2O2 began at much lower overpotentials (~240?mV) than the charge overpotentials of conventional Li-O2 cells with aprotic electrolytes (~1000?mV). Our study provides the first evidence of reversible lithium peroxide formation and decomposition in situ on an oxide surface using a solid-state cell, and new insights into the reaction mechanism of Li-O2 chemistry. PMID:23056907