Sample records for wavelength dispersive x-ray

  1. Wavelength Dispersive X-ray Absorption Fine Structure Imaging by Parametric X-ray Radiation

    Microsoft Academic Search

    Manabu Inagaki; Yasushi Hayakawa; Kyoko Nogami; Toshinari Tanaka; Ken Hayakawa; Takeshi Sakai; Keisuke Nakao; Isamu Sato

    2008-01-01

    The parametric X-ray radiation (PXR) generator system at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University is a monochromatic and coherent X-ray source with horizontal wavelength dispersion. The energy definition of the X-rays, which depends on the horizontal size of the incident electron beam on the generator target crystal, has been investigated experimentally by measuring the X-ray

  2. A multi-crystal wavelength dispersive x-ray spectrometer

    PubMed Central

    Alonso-Mori, Roberto; Kern, Jan; Sokaras, Dimosthenis; Weng, Tsu-Chien; Nordlund, Dennis; Tran, Rosalie; Montanez, Paul; Delor, James; Yachandra, Vittal K.; Yano, Junko; Bergmann, Uwe

    2012-01-01

    A multi-crystal wavelength dispersive hard x-ray spectrometer with high-energy resolution and large solid angle collection is described. The instrument is specifically designed for time-resolved applications of x-ray emission spectroscopy (XES) and x-ray Raman scattering (XRS) at X-ray Free Electron Lasers (XFEL) and synchrotron radiation facilities. It also simplifies resonant inelastic x-ray scattering (RIXS) studies of the whole 2d RIXS plane. The spectrometer is based on the Von Hamos geometry. This dispersive setup enables an XES or XRS spectrum to be measured in a single-shot mode, overcoming the scanning needs of the Rowland circle spectrometers. In conjunction with the XFEL temporal profile and high-flux, it is a powerful tool for studying the dynamics of time-dependent systems. Photo-induced processes and fast catalytic reaction kinetics, ranging from femtoseconds to milliseconds, will be resolvable in a wide array of systems circumventing radiation damage. PMID:22852678

  3. A multi-crystal wavelength dispersive x-ray spectrometer

    SciTech Connect

    Alonso-Mori, Roberto; Montanez, Paul; Delor, James; Bergmann, Uwe [LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Kern, Jan [LCLS, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-8099 (United States); Sokaras, Dimosthenis; Weng, Tsu-Chien; Nordlund, Dennis [SSRL, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Tran, Rosalie; Yachandra, Vittal K.; Yano, Junko [Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-8099 (United States)

    2012-07-15

    A multi-crystal wavelength dispersive hard x-ray spectrometer with high-energy resolution and large solid angle collection is described. The instrument is specifically designed for time-resolved applications of x-ray emission spectroscopy (XES) and x-ray Raman scattering (XRS) at X-ray Free Electron Lasers (XFEL) and synchrotron radiation facilities. It also simplifies resonant inelastic x-ray scattering (RIXS) studies of the whole 2d RIXS plane. The spectrometer is based on the Von Hamos geometry. This dispersive setup enables an XES or XRS spectrum to be measured in a single-shot mode, overcoming the scanning needs of the Rowland circle spectrometers. In conjunction with the XFEL temporal profile and high-flux, it is a powerful tool for studying the dynamics of time-dependent systems. Photo-induced processes and fast catalytic reaction kinetics, ranging from femtoseconds to milliseconds, will be resolvable in a wide array of systems circumventing radiation damage.

  4. Wavelength dispersive analysis with the synchrotron x ray fluorescence microprobe

    NASA Technical Reports Server (NTRS)

    Rivers, M. L.; Thorn, K. S.; Sutton, S. R.; Jones, K. W.; Bajt, S.

    1993-01-01

    A wavelength dispersive spectrometer (WDS) was tested on the synchrotron x ray fluorescence microprobe at Brookhaven National Laboratory. Compared to WDS spectra using an electron microprobe, the synchrotron WDS spectra have much better sensitivity and, due to the absence of bremsstrahlung radiation, lower backgrounds. The WDS spectrometer was successfully used to resolve REE L fluorescence spectra from standard glasses and transition metal K fluorescence spectra from kamacite.

  5. 12.141 Electron Microprobe Analysis by Wavelength Dispersive X-ray Spectrometry, January (IAP) 2006

    E-print Network

    Chatterjee, Nilanjan

    Introduction to the theory of x-ray microanalysis through the electron microprobe including ZAF matrix corrections. Techniques to be discussed are wavelength and energy dispersive spectrometry, scanning backscattered ...

  6. 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.

  7. Wavelength and energy dispersive X-ray studies of contaminants in water treed insulation

    Microsoft Academic Search

    A. Bulinski; S. Bamji; P. Timbrell; J. Densley

    1988-01-01

    The authors describe the results of an investigation to locate the contaminants within water trees grown in polymeric insulation using energy- and wavelength-dispersive X-ray (EDX and WDX) spectroscopy. Trees were grown in low-density polyethylene cross-linked polyethylene and dry-cured exposed to solutions of NaCl or CuSO4 at stresses up to 8 kV\\/mm. Some specimens examined semiconducting electrodes and also a semiconducting

  8. A wavelength dispersive detector for synchrotron x-ray fluorescence microprobe analysis (abstract)

    Microsoft Academic Search

    Mark L. Rivers; Stephen R. Sutton

    1995-01-01

    The synchrotron x-ray fluorescence (SXRF) microprobe has proven to be a valuable tool for trace element research. It permits analysis down to a few parts per million of many elements in a spot size of less than 10 ?m. Existing SXRF microprobes are using energy dispersive detectors (EDS), either Si(Li) or intrinsic Ge diodes. Such detectors have the advantage of

  9. 12.141 Electron Microprobe Analysis by Wavelength Dispersive X-ray Spectrometry, January IAP 2010

    E-print Network

    Chatterjee, Nilanjan

    2010-01-01

    This lab-oriented course introduces the student to the subject of X-ray spectrometry and micro-scale chemical quantitative analysis of solid samples through an intensive series of hands-on laboratory exercises that use the ...

  10. Online analysis of sulfur in diesel line by a monochromatic wavelength dispersive x-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Pérez-Careta, Eduardo; López-Ramírez, Juan Antonio; Reynoso-Whitaker, Gilberto; Sánchez-Mondragon, Javier; Torres-Cisneros, Miguel

    2009-09-01

    This paper proposes the application of a monochromatic wavelength dispersive X-ray fluorescence (MWDXRF) technique developed in the X-ray Optical Systems laboratory Inc. The technique measures low-level sulfur (uls) in fuel. Data for ultra low sulfur in diesel were collected and analyzed using the combination of the mentioned technique and the usage of engineering tools as a fastloop array and a measurement technique. This provides a qualitative method for Diesel sulfur analysis of the Refinery Ing. Antonio M Amor (RIAMA) in Salamanca, Guanajuato. The pooled limit of quantification (PLOQ) for ultra-low-sulfur diesel was found to be less than 1.5 ppm in this study. The reproducibility of 15-ppm sulfur diesel fuel was determined to be better than 3 ppm (95 % confident level). This work shows the performance of the production of Diesel with less than 15-ppm in sulfur lines in the Hydrodesulfurizer Unit of Diesel (HDD) of the refinery. Results and conclusions discusses the better and cheaper method for the production of ultra low sulfur Diesel in the refinery.

  11. A simultaneous multiple angle-wavelength dispersive X-ray reflectometer using a bent-twisted polychromator crystal

    PubMed Central

    Matsushita, Tadashi; Arakawa, Etsuo; Voegeli, Wolfgang; Yano, Yohko F.

    2013-01-01

    An X-ray reflectometer has been developed, which can simultaneously measure the whole specular X-ray reflectivity curve with no need for rotation of the sample, detector or monochromator crystal during the measurement. A bent-twisted crystal polychromator is used to realise a convergent X-ray beam which has continuously varying energy E (wavelength ?) and glancing angle ? to the sample surface as a function of horizontal direction. This convergent beam is reflected in the vertical direction by the sample placed horizontally at the focus and then diverges horizontally and vertically. The normalized intensity distribution of the reflected beam measured downstream of the specimen with a two-dimensional pixel array detector (PILATUS 100K) represents the reflectivity curve. Specular X-ray reflectivity curves were measured from a commercially available silicon (100) wafer, a thin gold film coated on a silicon single-crystal substrate and the surface of liquid ethylene glycol with data collection times of 0.01 to 1000?s using synchrotron radiation from a bending-magnet source of a 6.5?GeV electron storage ring. A typical value of the simultaneously covered range of the momentum transfer was 0.01–0.45?Å?1 for the silicon wafer sample. The potential of this reflectometer for time-resolved X-ray studies of irreversible structural changes is discussed. PMID:23254659

  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. Fabrication of high-throughput critical-angle X-ray transmission gratings for wavelength-dispersive spectroscopy

    E-print Network

    Bruccoleri, Alexander Robert

    2013-01-01

    The development of the critical-angle transmission (CAT) grating seeks both an order of magnitude improvement in the effective area, and a factor of three increase in the resolving power of future space-based, soft x-ray ...

  14. Multiple wavelength X-ray monochromators

    DOEpatents

    Steinmeyer, Peter A. (Arvada, CO)

    1992-11-17

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

  15. Multiple wavelength X-ray monochromators

    DOEpatents

    Steinmeyer, P.A.

    1992-11-17

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

  16. The use of integrated Energy (EDX) and Wavelength (WDX) Dispersive X-ray system for defects root cause analysis in an advanced logic fab

    Microsoft Academic Search

    R. Porat; A. Porst; J. Lohse; G. Matke; M. Rebien

    2010-01-01

    Over the last decade, integrated EDX (Energy Dispersive X-ray) systems on in-line SEM review tools have become the main method of providing the fab with a fast and efficient way to identify and reduce defects and yield limiting sources. As device sizes keep scaling down, the defects of interest size also becomes smaller, increasing the effective time needed for an

  17. Speciation of inorganic arsenic in drinking water by wavelength-dispersive X-ray fluorescence spectrometry after in situ preconcentration with miniature solid-phase extraction disks.

    PubMed

    Hagiwara, Kenta; Inui, Tetsuo; Koike, Yuya; Aizawa, Mamoru; Nakamura, Toshihiro

    2015-03-01

    A rapid and simple method using wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry after in situ solid-phase extraction (SPE) was developed for the speciation and evaluation of the concentration of inorganic arsenic (As) in drinking water. The method involves the simultaneous collection of As(III) and As(V) using 13 mm ? SPE miniature disks. The removal of Pb(2+) from the sample water was first conducted to avoid the overlapping PbL? and AsK? spectra on the XRF spectrum. To this end, a 50 mL aqueous sample (pH 5-9) was passed through an iminodiacetate chelating disk. The filtrate was adjusted to pH 2-3 with HCl, and then ammonium pyrrolidine dithiocarbamate solution was added. The solution was passed through a hydrophilic polytetrafluoroethylene filter placed on a Zr and Ca loaded cation-exchange disk at a flow rate of 12.5 mL min(-1) to separate As(III)-pyrrolidine dithiocarbamate complex and As(V). Each SPE disk was affixed to an acrylic plate using adhesive cellophane tape, and then examined by WDXRF spectrometry. The detection limits of As(III) and As(V) were 0.8 and 0.6 ?g L(-1), respectively. The proposed method was successfully applied to screening for As speciation and concentration evaluation in spring water and well water. PMID:25618730

  18. An angle-resolved, wavelength-dispersive x-ray fluorescence spectrometer for depth profile analysis of ion-implanted semiconductors using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Schmitt, W.; Hormes, J.; Kuetgens, U.; Gries, W. H.

    1992-01-01

    An apparatus for angle-resolved, wavelength-dispersive x-ray fluorescence spectroscopy with synchrotron radiation has been built and tested at the beam line BN2 of the Bonn electron stretcher and accelerator (ELSA). The apparatus is to be used for nondestructive depth profile analysis of ion-implanted semiconductors as part of the multinational Versailles Project of Advanced Materials and Standards (VAMAS) project on ion-implanted reference materials. In particular, the centroid depths of depth profiles of various implants is to be determined by use of the angle-resolved signal ratio technique. First results of measurements on implants of phosphorus (100 keV, 1016 cm-2) and sulfur (200 keV, 1014 cm-2) in silicon wafers using ``white'' synchrotron radiation are presented and suggest that it should be generally possible to measure the centroid depth of an implant at dose densities as low as 1014 cm-2. Some of the apparative and technical requirements are discussed which are peculiar to the use of synchrotron radiation in general and to the use of nonmonochromatized radiation in particular.

  19. Dispersion properties of x-ray waveguides

    SciTech Connect

    Pelliccia, D.; Bukreeva, I.; Cedola, A.; Lagomarsino, S

    2006-04-20

    We study the propagation of ultrashort pulses in x-ray waveguides (WGs) by addressing the problem of the temporal dispersion. Starting from basic equations, by means of numerical calculation we demonstrate that far from the absorption edges of the WGs the cladding's material dispersion is negligible. However, close to the absorption edge significant dispersion can take place. This behavior could in principle be exploited to manipulate incoming chirped beams. Moreover, using the two coherent beams produced by the WG in the second (and higher) order of resonance suggests the use of the WC as a dispersion-free beam splitter, which can facilitate x-ray pump-probe experiments in the femtosecond temporal range without the need for external sources.

  20. Spatiotemporal focusing dynamics in plasmas at X-ray wavelength

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Tibai, Z.; Hebling, J.; Mishra, S. K.

    2014-03-01

    Using a finite curvature beam, we investigate here the spatiotemporal focusing dynamics of a laser pulse in plasmas at X-ray wavelength. We trace the dependence of curvature parameter on the focusing of laser pulse and recognize that the self-focusing in plasma is more intense for the X-ray laser pulse with curved wavefront than with flat wavefront. The simulation results demonstrate that spatiotemporal focusing dynamics in plasmas can be controlled with the appropriate choice of beam-plasma parameters to explore the high intensity effects in X-ray regime.

  1. Spatiotemporal focusing dynamics in plasmas at X-ray wavelength

    SciTech Connect

    Sharma, A., E-mail: a-physics2001@yahoo.com; Tibai, Z. [Institute of Physics, University of Pecs, Pecs–7624 (Hungary)] [Institute of Physics, University of Pecs, Pecs–7624 (Hungary); Hebling, J. [Institute of Physics, University of Pecs, Pecs–7624 (Hungary) [Institute of Physics, University of Pecs, Pecs–7624 (Hungary); Szentagothai Research Centre, University of Pecs, Pecs-7624 (Hungary); Mishra, S. K. [Institute for Plasma Research, Gandhinagar (India)] [Institute for Plasma Research, Gandhinagar (India)

    2014-03-15

    Using a finite curvature beam, we investigate here the spatiotemporal focusing dynamics of a laser pulse in plasmas at X-ray wavelength. We trace the dependence of curvature parameter on the focusing of laser pulse and recognize that the self-focusing in plasma is more intense for the X-ray laser pulse with curved wavefront than with flat wavefront. The simulation results demonstrate that spatiotemporal focusing dynamics in plasmas can be controlled with the appropriate choice of beam-plasma parameters to explore the high intensity effects in X-ray regime.

  2. Theory of angular dispersive imaging hard x-ray spectrographs

    E-print Network

    Shvyd'ko, Yuri

    2015-01-01

    A spectrograph is an optical instrument that disperses photons of different energies into distinct directions and space locations, and images photon spectra on a position-sensitive detector. Spectrographs consist of collimating, angular dispersive, and focusing optical elements. Bragg reflecting crystals arranged in an asymmetric scattering geometry are used as the dispersing elements. A ray-transfer matrix technique is applied to propagate x-rays through the optical elements. Several optical designs of hard x-ray spectrographs are proposed and their performance is analyzed. Spectrographs with an energy resolution of 0.1 meV and a spectral window of imaging up to a few tens of meVs are shown to be feasible for inelastic x-ray scattering (IXS) spectroscopy applications. In another example, a spectrograph with a 1-meV spectral resolution and 85-meV spectral window of imaging is considered for Cu K-edge resonant IXS (RIXS).

  3. Carbon nanotubes as a solid sorbent for the preconcentration of Cr, Mn, Fe, Co, Ni, Cu, Zn and Pb prior to wavelength-dispersive X-ray fluorescence spectrometry.

    PubMed

    Zawisza, Beata; Skorek, Robert; Stankiewicz, Grazyna; Sitko, Rafal

    2012-09-15

    The preconcentration of trace elements on multiwalled carbon nanotubes (MWCNTs) followed by a wavelength-dispersive X-ray fluorescence analysis (WDXRF) has been investigated. The proposed preconcentration procedure is based on the sorption of trace elements on MWCNTs dispersed in analyzed solution. After sorption, the MWCNTs with the metal ions were collected onto the filter, and then the preconcentrated elements were determined directly by WDXRF. The preconcentration method was optimized, and in consequence, in order to obtain satisfactory recoveries using 100 mL of samples, the sorption process was performed with 1mg of MWCNTs within 5 min. Some conditions of the preconcentration process such as the pH of analyte solution, amounts of MWCNTs, the volume of the sample, the contact time between analytes and MWCNTs (stirring time), and the effects of foreign metals are discussed in detail in the paper. Adsorption onto raw and oxidized MWCNTs was also studied. The proposed procedure allows obtaining the detection limits of 0.6, 0.6, 1.0, 0.7, 0.6, 0.5, 0.9 and 1.9 ng mL(-1) for Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pb(II), respectively. The recoveries of determined elements were about 100%. Because the analytes are not eluted from the sorbent before WDXRF analysis, the risk of contamination and loss of analytes is reduced to minimum. Moreover, because the samples are analyzed as a thin layer, the matrix effects can be neglected. The proposed preconcentration method using MWCNTs coupled with WDXRF spectrometry was successfully applied to determine trace elements in natural water samples. PMID:22967643

  4. Point diffraction interferometry at soft x-ray wavelengths

    SciTech Connect

    Sommargren, G.E. [Lawrence Livermore National Lab., CA (United States); Hostetler, R. [AlliedSignal Technical Services, Livermore, CA (United States)

    1993-07-01

    To achieve the image performance necessary for soft x-ray projection lithography, interferometric testing at the design wavelength is required to accurately characterize the wavefront of the imaging system. The wavefront depends not only on the surface figure of the individual optics and on their relative alignment, but also on aperture dependent phase shifts induced by the resonant multilayer coatings on the optical surfaces. This paper describes the design and lithographic fabrication of an array of point diffraction interferometers on a silicon nitride membrane that has been over-coated with a spatially graded partially transmitting film to provide fringe contrast control. Experimental results using a visible light analogue (larger pinholes and different transmission gradient) will be shown.

  5. Analysis of nuclear materials by energy dispersive x-ray fluorescence and spectral effects of alpha decay

    SciTech Connect

    Worley, Christopher G [Los Alamos National Laboratory

    2009-01-01

    Energy dispersive X-ray fluorescence (EDXRF) spectra collected from alpha emitters are complicated by artifacts inherent to the alpha decay process, particularly when using portable instruments. For example, {sup 239}Pu EDXRF spectra exhibit a prominent uranium L X-ray emission peak series due to sample alpha decay rather than source-induced X-ray fluorescence. A portable EDXRF instrument was used to collect spectra from plutonium, americium, and a Pu-contaminated steel sample. The plutonium sample was also analyzed by wavelength dispersive XRF to demonstrate spectral differences observed when using these very different instruments.

  6. Phase dispersion X-ray imaging of murine soft tissue

    NASA Astrophysics Data System (ADS)

    Ingal, V. N.; Ingal, E. A.

    2013-12-01

    The generation of phase-contrast (PC) images in the phase-dispersion introscopy (PDI) technique is the subject of this paper. Conditions for extreme sensitivity to murine soft-tissue anatomy are discussed. The unique information content and good contrast of the minutest details of anatomy, together with the high brilliance of X-ray optics, give the authors confidence that the PDI method can be successfully applied for medical diagnostics.

  7. Portable energy dispersive X-ray fluorescence and X-ray diffraction and radiography system for archaeometry

    NASA Astrophysics Data System (ADS)

    Mendoza Cuevas, Ariadna; Perez Gravie, Homero

    2011-03-01

    Starting on a laboratory developed portable X-ray fluorescence (PXRF) spectrometer; three different analytical results can be performed: analysis of chemical elements, analysis of major chemical crystalline phase and structural analysis, which represents a contribution to a new, low cost development of portable X-ray analyzer; since these results are respectively obtained with independent equipments for X-ray fluorescence, X-ray diffraction and radiography. Detection limits of PXRF were characterized using standard reference materials for ceramics, glass, bronze and bones, which are the main materials requiring quantitative analysis in art and archeological objects. A setup for simultaneous energy dispersive X-ray fluorescence and diffraction (ED (XRF-XRD)) in the reflection mode has been tested for in situ and non-destructive analysis according to the requirements of art objects inspection. The system uses a single low power X-ray tube and an X-ray energy dispersive detector to measure X-ray diffraction spectrum at a fixed angle. Application to the identification of jadeite-jade mineral in archeological objects by XRD is presented. A local high resolution radiography image obtained with the same low power X-ray tube allows for studies in painting and archeological bones.

  8. Advances in understanding the anomalous dispersion of plasmas in the X-ray regime

    SciTech Connect

    Nilsen, J; Cheng, K T; Johnson, W R

    2008-09-24

    Over the last several years we have predicted and observed plasmas with an index of refraction greater than one in the soft X-ray regime. These plasmas are usually a few times ionized and have ranged from low-Z carbon plasmas to mid-Z tin plasmas. Our main computational tool has been the average atom code AVATOMKG that enables us to calculate the index of refraction for any plasma at any wavelength. In the last year we have improved this code to take into account many-atomic collisions. This allows the code to converge better at low frequencies. In this paper we present our search for plasmas with strong anomalous dispersion that could be used in X-ray laser interferometer experiments to help understand this phenomena. We discuss the calculations of anomalous dispersion in Na vapor and Ne plasmas near 47 nm where we predict large effects. We also discuss higher Z plasmas such as Ce and Yb plasmas that look very interesting near 47 nm. With the advent of the FLASH X-ray free electron laser in Germany and the LCLS X-FEL coming online at Stanford in another year we use the average atom code to explore plasmas at higher X-ray energy to identify potential experiments for the future. In particular we look near the K shell lines of near solid carbon plasmas and predict strong effects. During the next decade X-ray free electron lasers and other X-ray sources will be available to probe a wider variety of plasmas at higher densities and shorter wavelengths so understanding the index of refraction in plasmas will be even more essential.

  9. Searching for plasmas with anomalous dispersion in the soft X-ray regime

    SciTech Connect

    Nilsen, J; Johnson, W R; Cheng, K T

    2007-08-24

    Over the last decade the electron density of plasmas has been measured using X-ray laser interferometers in the 14 to 47 nm wavelength regime. With the same formula used in decades of experiments with optical interferometers, the data analysis assumes the index of refraction is due only to the free electrons, which makes the index less than one. Over the last several years, interferometer experiments in C, Al, Ag, and Sn plasmas have observed plasmas with index of refraction greater than one at 14 or 47 nm and demonstrated unequivocally that the usual formula for calculating the index of refraction is not always valid as the contribution from bound electrons can dominate the free electrons in certain cases. In this paper we search for other materials with strong anomalous dispersion that could be used in X-ray laser interferometer experiments to help understand this phenomena. An average atom code is used to calculate the plasma properties. This paper discusses the calculations of anomalous dispersion in Ne and Na plasmas near 47 nm and Xe plasmas near 14 nm. With the advent of the FLASH X-ray free electron laser in Germany and the LCLS X-FEL coming online at Stanford in 2 years the average atom code will be an invaluable tool to explore plasmas at higher X-ray energy to identify potential experiments for the future. During the next decade X-ray free electron lasers and other X-ray sources will be used to probe a wider variety of plasmas at higher densities and shorter wavelengths so understanding the index of refraction in plasmas will be even more essential.

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

    DOEpatents

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

    1985-01-01

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

  11. X-ray Spectrometry.

    ERIC Educational Resources Information Center

    Markowicz, Andrzej A.; Van Grieken, Rene E.

    1984-01-01

    Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

  12. 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

  13. 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

  14. Energy dispersive x-ray fluorescence analyzer with several x-ray tubes

    Microsoft Academic Search

    G. I. Borisov; R. I. Kondratenko; V. A. Mikhin; B. V. Odinov; A. V. Pukhov

    2005-01-01

    X-ray flurescent analyzer (XFA) has been developed and fabricated for determining sulphur, vanadium and nickel in oil. The instrument is equipped with three x-ray tubes with transmission Ti, Cu and Ag anodes, and aluminum, copper, and germanium filters, respectively, and one common switchable power supply. To excite characteristic radiation of determined elements, the characteristic radiation of the tube anode (titan,

  15. Energy dispersive X-ray reflectivity characterization of semiconductor heterostructures and interfaces

    SciTech Connect

    Chason, E.; Mayer, T.M. [Sandia National Labs., Albuquerque, NM (United States); Krstelj, Z.M. [Princeton Univ., NJ (United States)] [and others

    1995-07-01

    Energy dispersive X-ray reflectivity is a versatile tool for analyzing thin film structures. Layer thickness, interface roughness and composition can be determined with a single non-destructive measurement. Use of energy dispersive detection enables spectra to be acquired in less than 500 s with a rotating anode X-ray generator, making the study of kinetics possible.

  16. Scaling of Ne-like x-ray laser schemes to short wavelength

    SciTech Connect

    Rosen, M.D.; London, R.A.; Hagelstein, P.L.

    1988-03-01

    The driver and target parameters required to extend the successful results from an exploding foil Ne-like-Se soft x-ray laser at 206 A towards wavelengths of 40 A are investigated. The power requirements are found to scale as lambda/sup -4/, which is quite costly. The principal constraint is the refraction of the x-ray laser beam in these high density, single pass, exploding foil targets. Correcting mirrors or nonrefracting target designs could reduce this costly scaling.

  17. Variable magnification variable dispersion glancing incidence imaging x ray spectroscopic telescope

    NASA Technical Reports Server (NTRS)

    Hoover, Richard (inventor)

    1990-01-01

    A variable magnification variable dispersion glancing incidence x ray spectroscopic telescope capable of multiple high spatial revolution imaging at precise spectral lines of solar and stellar x ray and extreme ultraviolet radiation sources includes a primary optical system which focuses the incoming radiation to a primary focus. Two or more rotatable carriers each providing a different magnification are positioned behind the primary focus at an inclination to the optical axis, each carrier carrying a series of ellipsoidal diffraction grating mirrors each having a concave surface on which the gratings are ruled and coated with a multilayer coating to reflect by diffraction a different desired wavelength. The diffraction grating mirrors of both carriers are segments of ellipsoids having a common first focus coincident with the primary focus. A contoured detector such as an x ray sensitive photographic film is positioned at the second respective focus of each diffraction grating so that each grating may reflect the image at the first focus to the detector at the second focus. The carriers are selectively rotated to position a selected mirror for receiving radiation from the primary optical system, and at least the first carrier may be withdrawn from the path of the radiation to permit a selected grating on the second carrier to receive radiation.

  18. Development of high throughput X-ray telescopes for X-ray imaging and dispersive spectrometers

    NASA Technical Reports Server (NTRS)

    Gorenstein, P.

    1986-01-01

    During the past year the technical approach to the realization of a high throughput Kirkpatrick-Baez X-ray mirror became better defined in terms of construction methodology and factors which affect maximum size. More progress was made than anticipated in the area of automatic figure formation. However, effort to improve the resolution of float glass by simple techniques were not successful. Mirror development, spectroscopy, all sky telescope, and explorer concept studies are discussed.

  19. Short wavelength x-ray laser research at the Lawrence Livermore National Laboratory

    SciTech Connect

    MacGowan, B.J.; Da Silva, L.B.; Fields, D.J.; Keane, C.J.; Koch, J.A.; London, R.A.; Matthews, D.L.; Maxon, S.; Mrowka, S.; Osterheld, A.L.; Scofield, J.H.; Shimkaveg, G.; Trebes, J.E.; Walling, R.S. (Lawrence Livermore National Laboratory, University of California, L-476, P.O. Box 808, Livermore, California 94550 (United States))

    1992-07-01

    Laboratory x-ray lasers are currently being studied by researchers worldwide. This paper reviews some of the recent work carried out at Lawrence Livermore National Laboratory. Laser action has been demonstrated at wavelengths as short as 35.6 A while saturation of the small signal gain has been observed with longer wavelength schemes. Some of the most successful schemes to date have been collisionally pumped x-ray lasers that use the thermal electron distribution within a laser-produced plasma to excite electrons from closed shells in neon- and nickel-like ions to metastable levels in the next shell. Attempts to quantify and improve the longitudinal and transverse coherence of collisionally pumped x-ray lasers are motivated by the desire to produce sources for specific applications. Toward this goal there is a large effort underway to enhance the power output of the Ni-like Ta x-ray laser at 44.83 A as a source for x-ray imaging of live cells. Improving the efficiency of x-ray lasers in order to produce saturated output with smaller pump lasers is also a goal of this work.

  20. Energy dispersive x-ray fluorescence analyzer with several x-ray tubes

    NASA Astrophysics Data System (ADS)

    Borisov, G. I.; Kondratenko, R. I.; Mikhin, V. A.; Odinov, B. V.; Pukhov, A. V.

    2005-07-01

    X-ray flurescent analyzer (XFA) has been developed and fabricated for determining sulphur, vanadium and nickel in oil. The instrument is equipped with three x-ray tubes with transmission Ti, Cu and Ag anodes, and aluminum, copper, and germanium filters, respectively, and one common switchable power supply. To excite characteristic radiation of determined elements, the characteristic radiation of the tube anode (titan, copper) is used, or the charactersitic radiation of the filter (germanium). XFA is fitted with one small-size electrically cooled semiconductor detector. The measuring device is based on a wide-angle geometry of characteristic radiation excitation and registration, where the x-ray tube focus illuminates the sample, and the registering detector 'sees' the illuminated area within the plane angle of 90° (it corresponds to 0.146 of 4p). Under such geometry, the dependence of the count rate for excited characteristic photons on the position of sample under study has a smooth maximum in the calculated sample position point. For one, the rate count changes by less than 1%. Quantitative results are obtained through the regression method. The instrument underwent metrology testing. It is designed for operation both in the laboratory and industrial environment. The instrument has been delivered for operation to the "Druzhba" pipeline.

  1. The Chandra Multi-wavelength Project (ChaMP): X-ray Data Analysis

    NASA Astrophysics Data System (ADS)

    Kim, D.-W.; Cameron, R.; Drake, J.; Fruscione, A.; Gaetz, T. J.; Garcia, M.; Green, P. J.; Grimes, J.; Kashyap, V.; Prestwich, A.; Schlegel, E.; Vikhlinin, A.; Virani, S. N.; Wilkes, B.; Tananbaum, H.; Freedman, D.; ChaMP Collaboration

    2000-10-01

    We present step-by-step X-ray data analysis procedures as part of the Chandra Multi-wavelength Project. They consist of additional data corrections and data screening post CXC Standard Data Processing Rev 1 and the determination of sources and their X-ray properties. Using 3 deep ACIS imaging fields (MS 1137.5+6625, CL0848.6+4453 and A0620-00) with exposure times ranging from 50 ks to 190 ks, we discuss in particular gain correction, aspect correction, removing bad pixels and node boundaries, removing ACIS flaring pixels, streak correction for the S4 chip and excluding high background intervals. Optimal parameters for source detection and X-ray source properties such as X-ray colors are also discussed.

  2. Expanded potential of seleno-carbohydrates as a molecular tool for X-ray structural determination of a carbohydrate-protein complex with single/multi-wavelength anomalous dispersion phasing.

    PubMed

    Suzuki, Tatsuya; Makyio, Hisayoshi; Ando, Hiromune; Komura, Naoko; Menjo, Masanori; Yamada, Yusuke; Imamura, Akihiro; Ishida, Hideharu; Wakatsuki, Soichi; Kato, Ryuichi; Kiso, Makoto

    2014-04-01

    Seleno-lactoses have been successfully synthesized as candidates for mimicking carbohydrate ligands for human galectin-9 N-terminal carbohydrate recognition domain (NCRD). Selenium was introduced into the mono- or di-saccharides using p-methylselenobenzoic anhydride (Tol2Se) as a novel selenating reagent. The TolSe-substituted monosaccharides were converted into selenoglycosyl donors or acceptors, which were reacted with coupling partners to afford seleno-lactoses. The seleno-lactoses were converted to the target compounds. The structure of human galectin-9 NCRD co-crystallized with 6-MeSe-lactose was determined with single/multi-wavelength anomalous dispersion (SAD/MAD) phasing and was similar to that of the co-crystal with natural lactose. PMID:24631362

  3. 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

  4. Accounting for the dispersion in the x ray properties of early-type galaxies

    NASA Technical Reports Server (NTRS)

    White, Raymond E., III; Sarazin, Craig L.

    1990-01-01

    The x ray luminosities of early-type galaxies are correlated with their optical (e.g., blue) luminosities (L sub X approx. L sub B exp 1.6), but the x ray luminosities exhibit considerable scatter for a given optical luminosity L sub B. This dispersion in x ray luminosity is much greater than the dispersion of other properties of early-type galaxies (for a given L sub B), such as luminosity scale-length, velocity dispersion, color, and metallicity. Here, researchers consider several possible sources for the dispersion in x ray luminosity. Some of the scatter in x ray luminosity may result from stellar population variations between galaxies with similar L sub B. Since the x ray emitting gas is from accumulated stellar mass loss, the L sub X dispersion may be due to variations in integrated stellar mass loss rates. Another possible cause of the L sub X dispersion may be variations in the amount of cool material in the galaxies; cool gas may act as an energy sink for the hot gas. Infrared emission may be used to trace such cool material, so researchers look for a correlation between the infrared emission and the x ray emission of early-type galaxies at fixed L sub B. Velocity dispersion variations between galaxies of similar L sub B may also contribute to the L sub X dispersion. The most likely a priori source of the dispersion in L sub X is probably the varying amount of ram-pressure stripping in a range of galaxy environments. The hot gaseous halos of early-type galaxies can be stripped in encounters with other galaxies or with ambient cluster gas if the intracluster gas is sufficiently dense. Researchers find that the most likely cause of dispersion in the x ray properties of early type galaxies is probably the ram-pressure stripping of gaseous halos from galaxies. For a sample of 81 early-type galaxies with x ray luminosities or upper limits derived from Einstein Observatory observations (CFT) researchers calculated the cumulative distribution of angular distances between the x ray sample members and bright galaxies from the Revised Shapley - Ames catalog. Collectively, galaxies with low x ray luminosities (for a given L sub B) tend to be in denser environments than galaxies with higher x ray luminosities.

  5. At-wavelength metrology of x-ray optics at Diamond Light Source

    NASA Astrophysics Data System (ADS)

    Wang, Hongchang; Berujon, Sebastien; Sutter, John; Alcock, Simon G.; Sawhney, Kawal

    2014-09-01

    Modern, third-generation synchrotron radiation sources provide coherent and extremely bright beams of X-ray radiation. The successful exploitation of such beams depends to a significant extent on imperfections and misalignment of the optics employed on the beamlines. This issue becomes even more critical with the increasing use of active optics, and the desire to achieve diffraction-limited and coherence-preserving X-ray beams. In recent years, significant progress has been made to improve optic testing and optimization techniques, especially those using X-rays for so-called atwavelength metrology. These in-situ and at-wavelength metrology methods can be used not only to optimize the performance of X-ray optics, but also to correct and minimize the collective distortions of upstream beamline optics, including monochromators, and transmission windows. An overview of at-wavelength metrology techniques implemented at Diamond Light Source is presented, including grating interferometry and X-ray near-field speckle based techniques. Representative examples of the application of these techniques are also given, including in-situ and atwavelength calibration and optimization of: active, piezo bimorph mirrors; Kirkpatrick-Baez (KB) mirrors; and refractive optics such as compound refractive lenses.

  6. Experimental studies of X-ray emission physics and hydrodynamics using short wavelength lasers

    Microsoft Academic Search

    P. D. Goldstone; D. E. Casperson; J. A. Cobble; S. V. Coggeshall; C. C. Gomez; A. Hauer; G. A. Kyrala; P. H. Y. Lee; W. C. Mead; G. T. Schappert

    1988-01-01

    Several experimental efforts are currently under way at Low Alamos to study issues of importance for inertial confinement fusion with short wavelength lasers. These issues include the physics of X-ray conversion and the dynamics of short-wavelength laser interaction with high-Z plasmas; filamentation and self-focusing processes; and the growth of instabilities in laser-driven implosions. Most of these experiments are being pursued

  7. Superconducting Tunnel Junction Array Development for High-Resolution Energy-Dispersive X-ray Spectroscopy

    Microsoft Academic Search

    S. Friedrich; C. A. Mears; B. Nideröst; L. J. Hiller; M. Frank; S. E. Labov; A. T. Barfknecht; S. P. Cramer

    1998-01-01

    : Cryogenic energy-dispersive X-ray detectors are being developed because of their superior energy resolution (10 eV FWHM for keV X-rays) compared to that achieved in semiconductor energy-dispersive spectrometry (EDS) systems. So far, their range of application is limited because of their comparably small size and low count rate. We present data on the development of superconducting tunnel junction (STJ) detector

  8. Wavelength calibration of x-ray imaging crystal spectrometer on Joint Texas Experimental Tokamak

    SciTech Connect

    Yan, W.; Chen, Z. Y., E-mail: zychen@hust.edu.cn; Jin, W.; Huang, D. W.; Ding, Y. H.; Li, J. C.; Zhang, X. Q.; Zhuang, G. [School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan (China); Lee, S. G.; Shi, Y. J. [National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of)

    2014-11-15

    The wavelength calibration of x-ray imaging crystal spectrometer is a key issue for the measurements of plasma rotation. For the lack of available standard radiation source near 3.95 Å and there is no other diagnostics to measure the core rotation for inter-calibration, an indirect method by using tokamak plasma itself has been applied on joint Texas experimental tokamak. It is found that the core toroidal rotation velocity is not zero during locked mode phase. This is consistent with the observation of small oscillations on soft x-ray signals and electron cyclotron emission during locked-mode phase.

  9. Wavelength calibration of x-ray imaging crystal spectrometer on Joint Texas Experimental Tokamaka)

    NASA Astrophysics Data System (ADS)

    Yan, W.; Chen, Z. Y.; Jin, W.; Huang, D. W.; Ding, Y. H.; Li, J. C.; Zhang, X. Q.; Lee, S. G.; Shi, Y. J.; Zhuang, G.

    2014-11-01

    The wavelength calibration of x-ray imaging crystal spectrometer is a key issue for the measurements of plasma rotation. For the lack of available standard radiation source near 3.95 Å and there is no other diagnostics to measure the core rotation for inter-calibration, an indirect method by using tokamak plasma itself has been applied on joint Texas experimental tokamak. It is found that the core toroidal rotation velocity is not zero during locked mode phase. This is consistent with the observation of small oscillations on soft x-ray signals and electron cyclotron emission during locked-mode phase.

  10. Rest-wavelength Fiducials for the ITER Core Imaging X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Beiersdorfer, P.; Brown, G. V.; Graf, A. T.; Bitter, M.; Hill, K. W.; Kelley, R. L.; Kilbourne, C. A.; Leutenegger, M. A.; Porter, F. S.

    2012-01-01

    Absolute wavelength references are needed to derive the plasma velocities from the Doppler shift of a given line emitted by a moving plasma. We show that such reference standards exist for the strongest x-ray line in neonlike W64+, which has become the line of choice for the ITER (Latin the way) core imaging x-ray spectrometer. Close-by standards are the Hf L3 line and the Ir L2 line, which bracket the W64+ line by 30 eV; other standards are given by the Ir L1 and L2 lines and the Hf L1 and L2 lines, which bracket the W64+ line by 40 and 160 eV, respectively. The reference standards can be produced by an x-ray tube built into the ITER spectrometer. We present spectra of the reference lines obtained with an x-ray microcalorimeter and compare them to spectra of the W64+ line obtained both with an x-ray microcalorimeter and a crystal spectrometer

  11. In situ analysis of electrocrystallization process of metal electrodeposition with confocal energy dispersive X-ray diffraction based on polycapillary X-ray optics

    NASA Astrophysics Data System (ADS)

    Li, Fangzuo; Liu, Zhiguo; Sun, Tianxi; Yang, Chaolin; Sun, Weiyuan; Sun, Xuepeng; Ma, Yongzhong; Ding, Xunliang

    2015-06-01

    The confocal energy dispersive X-ray diffraction (EDXRD) based on a polycapillary focusing X-ray lens (PFXRL) in excitation channel and a polycapillary parallel X-ray lens (PPXRL) in detection channel was presented to study the electrocrystallization process of metal electrodeposition. The input focal spot of the PPXRL and the output focal spot of the PFXRL was adjusted in a confocal configuration, and only the X-rays from the volume overlapped by the two foci could be accordingly detected by the detector. The experimental results demonstrated the confocal EDXRD could be used to in situ real-time analysis of electrochemical crystal growth process.

  12. Single photon energy dispersive x-ray diffraction

    SciTech Connect

    Higginbotham, Andrew; Patel, Shamim; Ciricosta, Orlando; Suggit, Matthew J.; Wark, Justin S. [Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)] [Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Hawreliak, James A.; Collins, Gilbert W.; Coppari, Federica; Eggert, Jon H. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Tang, Henry [Department of Earth and Planetary Science, University of California Berkeley, Berkeley, California 94720 (United States)] [Department of Earth and Planetary Science, University of California Berkeley, Berkeley, California 94720 (United States)

    2014-03-15

    With the pressure range accessible to laser driven compression experiments on solid material rising rapidly, new challenges in the diagnosis of samples in harsh laser environments are emerging. When driving to TPa pressures (conditions highly relevant to planetary interiors), traditional x-ray diffraction techniques are plagued by increased sources of background and noise, as well as a potential reduction in signal. In this paper we present a new diffraction diagnostic designed to record x-ray diffraction in low signal-to-noise environments. By utilising single photon counting techniques we demonstrate the ability to record diffraction patterns on nanosecond timescales, and subsequently separate, photon-by-photon, signal from background. In doing this, we mitigate many of the issues surrounding the use of high intensity lasers to drive samples to extremes of pressure, allowing for structural information to be obtained in a regime which is currently largely unexplored.

  13. Microchannel plates and image detection at soft X-ray wavelengths

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.

    1986-01-01

    Detector systems based on the high-gain microchannel plate (MCP) electron multiplier have been used extensively for imaging at soft X-ray wavelengths both on the ground and in space. The latest pulse-counting electronic readout systems provide zero readout-noise, spatial resolutions (FWM) of 25 microns or better and can determine the arrival times of detected photons to an accuracy of the order of 100 ns. These systems can br developed to produce detectors with active areas of 100 mm in diameter or greater. The use of CsI photocathodes produces very high detective quantum efficiencies to wavelengths between about 100 and 1A (0.1 to 10 keV) with moderate energy resolution. The operating characteristics of the different types of soft X-ray MCP detector systems are described, and the prospects for future developments are discussed.

  14. Dispersive spread of virtual sources by asymmetricX-ray monochromators

    SciTech Connect

    Huang X. R.; Cai Y.; Macrander, A.T.; Honnicke, M.G.; Fernandez, P.

    2012-01-26

    The principles of the virtual source spread (spatial broadening) phenomenon induced by angular dispersion in asymmetric X-ray Bragg reflections are illustrated, from which the virtual source properties are analyzed for typical high-resolution multiple-crystal monochromators, including inline four-bounce dispersive monochromators, back-reflection-dispersion monochromators and nondispersive nested channel-cut monochromators. It is found that dispersive monochromators can produce spread virtual sources of a few millimetres in size, which may prevent efficient microfocusing of the beam as required by inelastic X-ray scattering spectroscopy and other applications. Possible schemes to mitigate this problem are discussed. The analyses may provide important guidelines for designing and optimizing modern high-precision synchrotron X-ray optics and beamline instrumentation for spectroscopy, imaging and nanofocusing applications.

  15. Clinical application of energy dispersive x-ray microanalysis for nondestructively confirming dental metal allergens.

    PubMed

    Hayashi, Y; Nakamura, S

    1994-06-01

    Dental metal restorations contain and release allergens that cause metal allergy. Until now it has been a general treatment for dental metal allergy to remove all suspected metal restorations without confirming their chemical composition. This study describes the procedures to examine nondestructively the chemical composition of metal restorations by the use of an energy dispersive x-ray microanalysis system. The present results indicate that this new application of energy dispersive x-ray microanalysis could identify the dental metal restorations that contain elements positive in skin tests for the patient in whom a metal allergy is suspected and that the potential for the clinical use of energy dispersive x-ray microanalysis exists. PMID:8065727

  16. X-Ray and Multi-Wavelength Observations of Gamma Ray Bursts (GRBs)

    NASA Technical Reports Server (NTRS)

    Kouveliotou, Chryssa

    2009-01-01

    The launch of the Italian (with Dutch participation) satellite BeppoSAX in 1996 enabled the detection of the first X-ray GRB afterglow, which in turn led to GRB counterpart detection in multiple wavelengths. This breakthrough firmly established the cosmological nature of GRBs. However, afterglow observations of GRBs took off in large numbers after the launch of NASA's Swift satellite in 2004. Swift enabled multiple major discoveries, such as the early lightcurves of X-ray afterglows, the first detection of a short GRB afterglow and opened more questions such as where are the elusive breaks in afterglow light curves. I will describe here these results and will discuss future opportunities and improvements in the field.

  17. 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 ...

  18. Time-Resolved X-Ray Reflectometry in the Multiwavelength Dispersive Geometry

    SciTech Connect

    Matsushita, Tadashi; Niwa, Yasuhiro [Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Arakawa, Etsuo [Department of Physics, Tokyo Gakugei University, Koganei, Tokyo (Japan); Harada, Tetsuo [LASTI, Univ. of Hyogo, Kamigoori-cho, Ako-gun, Hyogo (Japan); Hatano, Tadashi [Center for Advanced Microscopy and Spectroscopy, IMRAM, Tohoku University, Katahira, Aoba-ku, Sendai (Japan); Higashi, Yasuo [Engineering Center, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Yano, Yohko F. [Research Organization of Science and Engineering, Ritsumeikan University, Kusatsu-shi, Shiga (Japan); Inada, Yasuhiro [Department of Chemistry, Ritsumeikan University, Kusatsu-shi, Shiga (Japan); Nagano, Shusaku; Seki, Takahiro [Department of Molecular Design and Engineering, Nagoya University, Chigusa-ku, Nagoya (Japan)

    2010-06-23

    A new method of measuring specular X-ray reflectivity curves with a time resolution of milliseconds to seconds is developed. A horizontally convergent X-ray beam having a one-to-one correlation between its direction and energy is realized by a curved crystal or a laterally graded multilayer on an elliptic substrate. The X-ray beam is then incident on the surface of the specimen placed at the focus in such a way that the glancing angle in the vertical direction is the same for all X-ray components, which are reflected in the vertical direction by the surface and diverge in the horizontal plane. The perpendicular momentum transfer continuously changes as a function of the horizontal ray direction since the wavelength change similarly. The normalized linear intensity distribution across the beam direction measured downstream of the specimen represents the X-ray reflectivity curve. Examples of time-resolved measurements of X-ray reflectivity curves are shown.

  19. Using angular dispersion and anomalous transmission to shape ultramonochromatic x rays

    SciTech Connect

    Shvyd'ko, Yuri; Stoupin, Stanislav; Shu, Deming; Khachatryan, Ruben [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2011-11-15

    Optical spectrometers, instruments that work with highly monochromatic light, are commonly rated by the spectral bandwidth, which defines the ability to resolve closely spaced spectral components. Another equally important feature is the spectral contrast, the ability to detect faint objects among these components. Here we demonstrate that a combined effect of angular dispersion (AD) and anomalous transmission (AT) of x rays in Bragg reflection from asymmetrically cut crystals can shape spectral distributions of x rays to profiles with high contrast and small bandwidths. The AD and AT x-ray optics is implemented as a five-reflection, three-crystal arrangement featuring a combination of the above-mentioned attributes so desirable for x-ray monochromators and analyzers: a spectral contrast of {approx_equal} 500, a bandwidth of {approx_equal} 0.46 meV, and a remarkably large angular acceptance of {approx_equal} 107 {mu}rad with 9.1 keV x rays. The new optics can become a foundation for the next-generation inelastic x-ray scattering spectrometers for studies of atomic dynamics.

  20. Macromolecular X-ray structure determination using weak, single-wavelength anomalous data.

    PubMed

    Bunkóczi, Gábor; McCoy, Airlie J; Echols, Nathaniel; Grosse-Kunstleve, Ralf W; Adams, Paul D; Holton, James M; Read, Randy J; Terwilliger, Thomas C

    2015-02-01

    We describe a likelihood-based method for determining the substructure of anomalously scattering atoms in macromolecular crystals that allows successful structure determination by single-wavelength anomalous diffraction (SAD) X-ray analysis with weak anomalous signal. With the use of partial models and electron density maps in searches for anomalously scattering atoms, testing of alternative values of parameters and parallelized automated model-building, this method has the potential to extend the applicability of the SAD method in challenging cases. PMID:25532136

  1. Energy Dispersive X Ray Diffraction to identify Explosive Substances : spectra analysis procedure optimization

    E-print Network

    Paris-Sud XI, Université de

    , France tel: 0033472437084 Abstract: To detect the presence of explosives in packages, automated systems for explosive detection and identification. To this end, a database has been constructed, containing measured X: Explosives detection, X-ray diffraction, non destructive testing 1. Introduction Energy dispersive X

  2. Determination of argon in sputtered silicon films by energy-dispersive x-ray fluorescence spectrometry

    Microsoft Academic Search

    Dennis J. Kalnicky; T. D. Moustakas

    1981-01-01

    Hydrogenated amorphous silicon can be prepared by glow discharge decomposition of silane or by reactive sputtering in an argon + hydrogen plasma. The sputtered films contain some percentage of argon incorporated in them and its role in determining the physical properties of these materials is of interest. This paper describes energy-dispersive x-ray fluorescence (EDXRF) methods which were developed to characterize

  3. Polarized Energy Dispersive X-ray Fluorescence Applications of Spice Samples

    Microsoft Academic Search

    Zafer Üstünda?

    2009-01-01

    In this study, the elemental concentrations of some spice plants gathered from Mut-Mersin in Turkey were analyzed by polarized energy dispersive x-ray fluorescence (PEDXRF) spectrometry. The analyzed spices are peppermint (Mentha piperita), thyme (Thymus vulgaris), and sumac (Rhus glabra). These samples are very often used in the preparation of Turkish foods. The spice samples are indispensable in foods for Turkish

  4. Energy-Dispersive X-Ray Fluorescence Spectrometry: A Long Overdue Addition to the Chemistry Curriculum

    ERIC Educational Resources Information Center

    Palmer, Peter T.

    2011-01-01

    Portable Energy-Dispersive X-Ray Fluorescence (XRF) analyzers have undergone significant improvements over the past decade. Salient advantages of XRF for elemental analysis include minimal sample preparation, multielement analysis capabilities, detection limits in the low parts per million (ppm) range, and analysis times on the order of 1 min.…

  5. Analysis of tincal ore waste by energy dispersive X-ray fluorescence (EDXRF) Technique

    NASA Astrophysics Data System (ADS)

    Kalfa, Orhan Murat; Üstünda?, Zafer; Özk?r?m, Ilknur; Kagan Kad?o?lu, Yusuf

    2007-01-01

    Etibank Borax Plant is located in K?rka-Eski?ehir, Turkey. The borax waste from this plant was analyzed by means of energy dispersive X-ray fluorescence (EDXRF). The standard addition method was used for the determination of the concentration of Al, Fe, Zn, Sn, and Ba. The results are presented and discussed in this paper.

  6. Phonon dispersion in uranium measured using inelastic x-ray scattering.

    SciTech Connect

    Manley, M. E.; Lander, G. H.; Sinn, H.; Alatas, A.; Hults, W. L.; McQueeney, R. J.; Smith, J. L.; Wilt, J.; XFD

    2003-02-01

    Phonon-dispersion curves were obtained from inelastic x-ray scattering measurements on high-purity uranium single crystals at room temperature. Modes displacing atoms along [00{zeta}] and propagating in all three high-symmetry directions were measured. Whereas the acoustic modes agree with the neutron measurements, the longitudinal-optic branch is about 10% higher in energy, but consistent with higher cutoff energies observed in phonon density-of-states measurements on polycrystals. The application of this x-ray technique, which requires only very small samples, opens possibilities in actinide science.

  7. High-pressure structural studies of dysprosium using angle-dispersive x-ray diffraction

    SciTech Connect

    Shen Yongrong; Kumar, Ravhi S.; Cornelius, Andrew L.; Nicol, Malcolm F. [Department of Physics and High Pressure Science and Engineering Center, University of Nevada Las Vegas, Las Vegas, Nevada 89154-4002 (United States)

    2007-02-01

    We present structural results under pressure for elemental dysprosium (Dy) up to 87 GPa using in situ angle-dispersive x-ray diffraction measurements with synchrotron x rays and a diamond-anvil cell. Dy exhibits the structural transition sequence, hP2{yields}hR9{yields}hP4{yields}distorted cF4, from Rietveld full-profile refinements. Clear evidence is documented for the high-pressure distorted cF4 phase observed above 45 GPa to be an orthorhombic oS8 (Cmmm) structure for Dy in the lanthanide phase diagram.

  8. The 20 element HgI2 energy dispersive x ray array detector system

    NASA Astrophysics Data System (ADS)

    Iwanczyk, J. A.; Dorri, N.; Wang, M.; Szczebiot, R. W.; Dabrowski, A. J.; Hedman, B.; Hodgson, K. O.; Patt, B. E.

    1991-11-01

    This paper describes recent progress in the development of HgI2 energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K(sub a)) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel.

  9. Experimental studies of x-ray emission physics and hydrodynamics using short wavelength lasers

    SciTech Connect

    Goldstone, P.D.; Casperson, D.E.; Cobble, J.A.; Coggeshall, S.V.; Gomez, C.C.; Hauer, A.; Kyrala, G.A.; Lee, P.H.Y.; Mead, W.C.; Schappert, G.T.

    1988-01-01

    Several experimental efforts are currently under way at Low Alamos to study issues of importance for inertial confinement fusion with short wavelength lasers. These issues include the physics of x-ray conversion and the dynamics of short-wavelength laser interaction with high-Z plasmas; filamentation and self-focusing processes; and the growth of instabilities in laser-driven implosions. Most of these experiments are being pursued in collaboration with other laboratories, notably the University of Rochester and Lawrence Livermore National Laboratory. In addition, we are undertaking basic studies of the interaction of both atomic systems and solids with ultra-intense (/approximately/10/sup 17/ W/cm/sup 2/) subpicosecond lasers at Los Alamos. These experiments explore the response of atomic systems to strong fields, multiphoton excitation, and transient phenomena in dense plasmas. 15 refs., 3 figs.

  10. Theory of angular-dispersive, imaging hard-x-ray spectrographs

    NASA Astrophysics Data System (ADS)

    Shvyd'ko, Yuri

    2015-05-01

    A spectrograph is an optical instrument that disperses photons of different energies into distinct directions and space locations and that images photon spectra on a position-sensitive detector. Spectrographs consist of collimating, angular dispersive, and focusing optical elements. Bragg reflecting crystals arranged in an asymmetric scattering geometry can be used as the dispersing elements in the hard-x-ray regime. A ray-transfer matrix technique is applied to propagate x-rays through the optical elements. Several optical designs of hard-x-ray spectrographs are proposed and their performance is analyzed. Spectrographs with an energy resolution of 0.1 meV and a spectral window of imaging up to a few tens of meVs are shown to be feasible for inelastic x-ray scattering (IXS) spectroscopy applications. In another example, a spectrograph with a 1-meV spectral resolution and 85-meV spectral window of imaging is considered for Cu K -edge resonant IXS.

  11. Novel wavelength-dispersive X-ray fluorescence spectrometer

    NASA Astrophysics Data System (ADS)

    Firsov, A.; Erko, A.; Senf, F.; Rehanek, J.; Brzhezinskaya, M.; Wernet, R. Mitzner Ph; Föhlisch, A.

    2013-03-01

    A new spectrometer, utilizing a reflection zone plate based grating, for the Mn L fluorescence line was recently designed, manufactured and tested at Helmholtz Zentrum Berlin. The angular acceptance of the grating is ~0.011 rad2 the absolute efficiency at 640 eV is 16%, and the energy resolution, for a detector slit size of 120 ?m and in simultaneous spectra registration mode, is about ?/?? ~ 100 FWHM.

  12. Short-wavelength soft-x-ray laser pumped in double-pulse single-beam non-normal incidence

    SciTech Connect

    Zimmer, D. [LASERIX-CLUPS, LPGP UMR 8578, Universite Paris-Sud 11, F-91405 Orsay (France); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany); Ros, D.; Guilbaud, O.; Habib, J.; Kazamias, S. [LASERIX-CLUPS, LPGP UMR 8578, Universite Paris-Sud 11, F-91405 Orsay (France); Zielbauer, B. [LASERIX-CLUPS, LPGP UMR 8578, Universite Paris-Sud 11, F-91405 Orsay (France); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Helmholtz Institut Jena, Friedrich-Schiller Universitaet, D-07743 Jena (Germany); Bagnoud, V. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Helmholtz Institut Jena, Friedrich-Schiller Universitaet, D-07743 Jena (Germany); Ecker, B.; Aurand, B.; Kuehl, T. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany); Helmholtz Institut Jena, Friedrich-Schiller Universitaet, D-07743 Jena (Germany); Hochhaus, D. C.; Neumayer, P. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Institut fuer Angewandte Physik, Goethe-Universitaet Frankfurt am Main, D-60438 Frankfurt am Main (Germany)

    2010-07-15

    We demonstrated a 7.36 nm Ni-like samarium soft-x-ray laser, pumped by 36 J of a neodymium:glass chirped-pulse amplification laser. Double-pulse single-beam non-normal-incidence pumping was applied for efficient soft-x-ray laser generation. In this case, the applied technique included a single-optic focusing geometry for large beam diameters, a single-pass grating compressor, traveling-wave tuning capability, and an optimized high-energy laser double pulse. This scheme has the potential for even shorter-wavelength soft-x-ray laser pumping.

  13. Closing the gap to the diffraction limit: Near wavelength limited tabletop soft x-ray coherent diffractive imaging

    NASA Astrophysics Data System (ADS)

    Sandberg, Richard Lunt

    Light microscopy has greatly advanced our understanding of nature. The achievable resolution, however, is limited by optical wavelengths to around 200 nm. Using novel imaging and labeling technologies, resolutions beyond the diffraction limit can be achieved for specialized specimens using techniques such as near-field scanning optical microscopy, stimulated emission depletion microscopy and structured illumination microscopy [1--3]. This dissertation presents a versatile soft x-ray diffraction microscope with 50 nm resolution using tabletop coherent soft x-ray sources. This work represents the first high resolution demonstrations of coherent diffractive or lensless imaging using tabletop extreme ultraviolet and soft x-ray sources [4, 5]. This dissertation also presents the first use of field curvature correction in x-ray coherent imaging which allows high numerical aperture imaging and near-diffraction-limited resolution of 1.5lambda. The relevant theory behind high harmonic generation, the primary tabletop source used in this work, will be discussed as well as the theory behind coherent diffractive imaging. Additionally, the first demonstration of tabletop soft x-ray Fourier Transform holography is shown with important applications to shorter wavelength imaging with high harmonic generation with limited flux. A tabletop soft x-ray diffraction microscope should find broad applications in biology, nanoscience, and materials science due to its simple optical design, high resolution, large depth of field, 3D imaging capability, scalability to shorter wavelengths, and ultrafast temporal resolution.

  14. Dispersion and monochromatization of x-rays using a beryllium prism.

    PubMed

    Burza, M; Enquist, H; Jurgilaitis, A; Nygaard, J; Larsson, J

    2015-01-26

    We demonstrate experimentally and numerically that an x-ray prism made of beryllium can be used to disperse and monochromatize x-rays. A polished beryllium cuboid was employed as refractive and dispersive optics. The results of a proof-of-principle experiment and methods of performance optimization are presented. The spatial separation of undulator harmonics and their subsequent selection using a slit are described. A numerical study, assuming realistic beam and beamline parameters, suggests that undulator harmonics can be spatially separated in the range from 3 keV to beyond 20 keV, while maintaining throughput above 50%. Refractive optics is particularly suitable for low-repetition-rate sources such as free-electron lasers and other LINAC-based short-pulse sources. PMID:25835820

  15. Energy Dispersive X-ray Diffraction (Edxd) Investigation Of Amorphous Poly(phenylacetylene) (Ppa)

    Microsoft Academic Search

    Alessandro Isopo; Ruggero Caminiti; Rosaria DAmato; Anita Furlani; Maria V. Russo

    2003-01-01

    The application of wide-angle x-ray diffraction in energy-dispersive modality (EDXD) to the investigation of the static structure of amorphous poly(phenylacetylene) (PPA) is discussed. The structural investigation was carried out through the systematic comparison of the measured functions (the reduced interference function and the radial distribution function) and the same functions calculated from three-dimensional theoretical models, suitably optimized. Possible configurations and

  16. 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

  17. Scanning electron microscope/energy dispersive x ray analysis of impact residues in LDEF tray clamps

    NASA Technical Reports Server (NTRS)

    Bernhard, Ronald P.; Durin, Christian; Zolensky, Michael E.

    1993-01-01

    Detailed optical scanning of tray clamps is being conducted in the Facility for the Optical Inspection of Large Surfaces at JSC to locate and document impacts as small as 40 microns in diameter. Residues from selected impacts are then being characterized by Scanning Electron Microscopy/Energy Dispersive X-ray Analysis at CNES. Results from this analysis will be the initial step to classifying projectile residues into specific sources.

  18. The identification of burnt matches by scanning electron microscopy\\/energy dispersive X-ray spectrometry

    Microsoft Academic Search

    Yueh-Hsiang Chen

    This study is first placed on the characterization of various burnt matches by scanning electron microscopy\\/energy dispersive X-ray spectrometry (SEM\\/EDS). The morphological and elemental features were used to investigate fire residues and to increase the discriminating effect of burnt matches. To find if there was further discrimination method, the cluster analysis of 74 boxes of matches based on the semi-quantitative

  19. Soft x-ray laser holography with wavelength P. W. Wachulak, M. C. Marconi,* R. A. Bartels, C. S. Menoni, and J. J. Rocca

    E-print Network

    Rocca, Jorge J.

    Soft x-ray laser holography with wavelength resolution P. W. Wachulak, M. C. Marconi,* R. A the tabletop acquisition of soft x-ray holographic images of nanostructures with a spatial resolution of 46 using a compact, tabletop capillary-discharge soft x-ray laser emitting at 46.9 nm in a high

  20. Clinical applications of scanning electron microscopy and energy dispersive X-ray analysis in dermatology--an up-date

    Microsoft Academic Search

    Forslind

    1988-01-01

    Dermatological papers comprising scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis data published 1983 through 1986 in international journals are reviewed, as an update to our 1984 paper on Clinical applications of scanning electron microscopy and X-ray microanalysis in dermatology. The present paper not only deals with a review of recent publications in this area but also presents

  1. THE CORRELATION BETWEEN DISPERSION MEASURE AND X-RAY COLUMN DENSITY FROM RADIO PULSARS

    SciTech Connect

    He, C.; Ng, C.-Y.; Kaspi, V. M., E-mail: ncy@bohr.physics.hku.hk [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada)

    2013-05-01

    Pulsars are remarkable objects that emit across the entire electromagnetic spectrum, providing a powerful probe of the interstellar medium. In this study, we investigate the relation between dispersion measure (DM) and X-ray absorption column density N{sub H} using 68 radio pulsars detected at X-ray energies with the Chandra X-Ray Observatory or XMM-Newton. We find a best-fit empirical linear relation of N{sub H} (10{sup 20} cm{sup -2})= 0.30{sup +0.13}{sub -0.09} DM (pc cm{sup -3}), which corresponds to an average ionization of 10{sup +4}{sub -3}%, confirming the ratio of one free electron per 10 neutral hydrogen atoms commonly assumed in the literature. We also compare different N{sub H} estimates and note that some N{sub H} values obtained from X-ray observations are higher than the total Galactic H I column density along the same line of sight, while the optical extinction generally gives the best N{sub H} predictions.

  2. 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

  3. 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.

  4. Thermoelectrically cooled semiconductor detectors for portable energy-dispersive x-ray fluorescence equipment

    NASA Astrophysics Data System (ADS)

    Cesareo, Roberto; Castellano, Alfredo; Fiorini, Carlo; Gigante, Giovanni E.; Iwanczyk, Jan S.; Longoni, Antonio; Pantazis, John A.; Pena Chapa, Juan L.; Rosales, Marco A.

    1997-07-01

    Thermoelectrically cooled semiconductor detectors, such as Si- PIN, Si-strip and HgI(subscript 2), coupled to miniaturized low-power x-ray tubes, are well suited for constructing portable systems for energy-dispersive x-ray fluorescence analysis (EDXRF) of samples of archaeological interest. The Si-PIN detector is characterized by a thickness of about 300 micrometer, an area of about 2 by 3 mm(superscript 2), an energy resolution of about 250 - 300 eV at 5.9 keV and an entrance window of 75 micrometers. The Si-strip detector has approximate the same area and thickness, but an energy resolution of 145 eV at 5.9 keV. The efficiency of these detectors is around 100% from 4 to 10 keV, and then decreases versus energy, reaching 10% at 30 keV. Coupled to a miniaturized 10 kV, 0.1 mA, Ca-anode or to a miniaturized 30 kV, 0.1 mA, W-anode x-ray tubes, completely portable systems can be constructed, which are able to analyze K-lines of elements up to about silver, and L-lines of heavy elements. The HgI(subscript 2) detector has an efficiency of about 100% in the whole range of x rays, and an energy resolution of about 200 eV at 5.9 keV. Coupled to a small 50 kV, 1 mA, W- anode x-ray tube, a portable system can be constructed, for analysis of practically all elements. These equipments were applied to analysis in the field of archaeometry and in all applications for which portable systems are needed or at least useful (for example x-ray transmission measurements, x-ray microtomography and so on). More specifically, concerning EDXRF analysis, ancient gold samples were analyzed in Rome, in Mexico City and in Milan, nuragic bronzes in Sassari, ceramics of various origin in Merida, La Habana and Sassari, and sulfur (due to pollution) in an old Roman fresco in S. Stefano Rotondo (Rome). Concerning transmission measurements, ancient copper coins and wood samples were analyzed, and microtomographic measurements are in progress to improve the quality of the image.

  5. High-resolution microcalorimeter energy-dispersive spectrometer for x-ray microanalysis and particle analysis

    SciTech Connect

    Wollman, D. A.; Hilton, G. C.; Irwin, K. D.; Dulcie, L. L.; Bergren, N. F.; Martinis, John M. [National Institute of Standards and Technology (NIST), Boulder, Colorado 80303 (United States); Newbury, Dale E. [National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899 (United States); Woo, Keung-Shan; Liu, Benjamin Y. H. [University of Minnesota, Minneapolis, Minnesota 55455 (United States); Diebold, Alain C. [SEMATECH, 2706 Montopolis Drive, Austin, Texas 78731 (United States)

    1998-11-24

    We have developed a high-resolution microcalorimeter energy-dispersive spectrometer (EDS) at NIST that provides improved x-ray microanalysis of contaminant particles and defects important to the semiconductor industry. Using our microcalorimeter EDS mounted on a scanning electron microscope (SEM), we have analyzed a variety of specific sized particles on Si wafers, including 0.3 {mu}m diameter W particles and 0.1 {mu}m diameter Al{sub 2}O{sub 3} particles. To compare the particle analysis capabilities of microcalorimeter EDS to that of semiconductor EDS and Auger electron spectroscopy (AES), we report measurements of the Al-K{alpha}/Si-K{alpha} x-ray peak intensity ratio for 0.3 {mu}m diameter Al{sub 2}O{sub 3} particles on Si as a function of electron beam energy. We also demonstrate the capability of microcalorimeter EDS for chemical shift measurements.

  6. Superconducting tunnel junction array development for high-resolution energy-dispersive x-ray spectroscopy

    SciTech Connect

    Barfknecht, A. T.; Cramer, S. P; Frank, M.; Friedrich, S.; Hiller, L. J.; Labov, S. E.; Mears, C. A.; Niderost, B.

    1998-07-01

    Cryogenic energy-dispersive x-ray detectors are being developed because of their superior energy resolution ((less than or equal to) 10 eV FWHM for keV x rays) compared to semiconductor EDS systems. So far, their range of application is limited due to their comparably small size and low count rate. We present data on the development of superconducting tunnel junction (STJ) detector arrays to address both of these issues. A single STJ detector has a resolution around 10 eV below 1 keV and can be operated at count rates of order 10,000 counts/s. We show that the simultaneous operation of several STJ detectors does not diminish their energy resolution significantly, while increasing the detector area and the maximum count rate by a factor given by the total number of independent channels.

  7. Energy Dispersive Spectrometry and Quantitative Analysis Short Course. Introduction to X-ray Energy Dispersive Spectrometry and Quantitative Analysis

    NASA Technical Reports Server (NTRS)

    Carpenter, Paul; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    This course will cover practical applications of the energy-dispersive spectrometer (EDS) to x-ray microanalysis. Topics covered will include detector technology, advances in pulse processing, resolution and performance monitoring, detector modeling, peak deconvolution and fitting, qualitative and quantitative analysis, compositional mapping, and standards. An emphasis will be placed on use of the EDS for quantitative analysis, with discussion of typical problems encountered in the analysis of a wide range of materials and sample geometries.

  8. Characterization of "oil on copper" paintings by energy dispersive X-ray fluorescence spectrometry.

    PubMed

    Pitarch, A; Ramón, A; Álvarez-Pérez, A; Queralt, I

    2012-02-01

    Energy dispersive X-ray fluorescence is a common analytical tool for layer thickness measurements in quality control processes in the coating industry, but there are scarce microanalytical applications in order to ascertain semi-quantitative or quantitative information of painted layers. "Oil on copper" painting becomes a suitable material to be analysed by means of X-ray fluorescence spectrometry, due to the metallic nature of substrate and the possibility of applying layered models as used in coating industry. The aim of this work is to study the suitability of a quantitative energy dispersive X-ray fluorescence methodology for the assessment of the areal distribution of pigments and the characterization of painting methods on such kind of pictorial artworks. The method was calibrated using standard reference materials: dried droplets of monoelemental standard solutions laid on a metallic plate of copper. As an example of application, we estimated pigment mass distribution of two "oil on copper" paintings from the sixteenth and eighteenth centuries. Pictorial layers have been complementarily analysed by X-ray diffraction. Apart of the supporting media made of copper or brass, we could identify two different superimposed layers: (a) a preparation layer mainly composed by white lead and (b) the pictorial layer of variable composition depending on the pigments used by the artist on small areas of the painting surface. The areal mass distribution of the different elements identified in the painting pigments (Ca, Cr, Mn, Fe, Zn, Cd, Hg and Pb) have been determined by elemental mapping of some parts of the artworks. PMID:21904800

  9. At-wavelength characterization of refractive x-ray lenses using a two-dimensional grating interferometer

    SciTech Connect

    Rutishauser, Simon; David, Christian [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Zanette, Irene [European Synchrotron Radiation Facility, 38043 Grenoble (France); Weitkamp, Timm [Synchrotron Soleil, 91192 Gif-sur-Yvette (France); Donath, Tilman [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Dectris Ltd., 5400 Baden (Switzerland)

    2011-11-28

    We report on the application of a two-dimensional hard x-ray grating interferometer to x-ray optics metrology. The interferometer is sensitive to refraction angles in two perpendicular directions with a precision of 10 nrad. It is used to observe the wavefront changes induced by a single parabolic beryllium focusing lens of large radius of curvature. The lens shape is reconstructed and its residual aberrations are analyzed. Its profile differs from an ideal parabolic shape by less than 2 {mu}m or {lambda}/50 at {lambda} = 0.54 A wavelength.

  10. [Application of in situ micro energy dispersive X-ray fluorescence analysis in mineralogy].

    PubMed

    Yang, Hai; Ge, Liang-Quan; Gu, Yi; Zhang, Qing-Xian; Xiong, Sheng-Qing

    2013-11-01

    Thirteen rock samples were collected for studying the variation of element content in the mineral during the alteration process from Xinjiang, China. The IED-6000 in situ micro energy dispersive X-ray fluorescence developed by CDUT was applied to get chemical and physical data from minerals. The non-destructive spectrometer is based on a low-power Mo-anode X-ray tube and a Si-PIN peltier cooled X-ray detector. The unique design of the tube's probe allows very close coupling of polycapillary and makes the use of micro-area measurement feasible and efficient. The spectrometer can be integrated into any microscope for analysis. The long axis diameter of beam spot is about 110 microm. According to micro-EDXRF measurement, the tetrahedrite was corrected to pyrite, improving the efficiency and accuracy of the mineral identification. The feldspar of mineralized rock sample is rich in Cu and Zn which can be used as prospecting indicator elements. Element content of Cr, Mn and Co shows negative correlation with the degree of mineralization. PMID:24555398

  11. Multi-wavelength Observations of Solar Flares with a Constrained Peak X-Ray Flux

    NASA Astrophysics Data System (ADS)

    Bowen, Trevor A.; Testa, Paola; Reeves, Katharine K.

    2013-06-01

    We present an analysis of soft X-ray (SXR) and extreme-ultraviolet (EUV) observations of solar flares with an approximate C8 Geostationary Operational Environmental Satellite (GOES) class. Our constraint on peak GOES SXR flux allows for the investigation of correlations between various flare parameters. We show that the duration of the decay phase of a flare is proportional to the duration of its rise phase. Additionally, we show significant correlations between the radiation emitted in the flare rise and decay phases. These results suggest that the total radiated energy of a given flare is proportional to the energy radiated during the rise phase alone. This partitioning of radiated energy between the rise and decay phases is observed in both SXR and EUV wavelengths. Though observations from the EUV Variability Experiment show significant variation in the behavior of individual EUV spectral lines during different C8 events, this work suggests that broadband EUV emission is well constrained. Furthermore, GOES and Atmospheric Imaging Assembly data allow us to determine several thermal parameters (e.g., temperature, volume, density, and emission measure) for the flares within our sample. Analysis of these parameters demonstrate that, within this constrained GOES class, the longer duration solar flares are cooler events with larger volumes capable of emitting vast amounts of radiation. The shortest C8 flares are typically the hottest events, smaller in physical size, and have lower associated total energies. These relationships are directly comparable with several scaling laws and flare loop models.

  12. MULTI-WAVELENGTH OBSERVATIONS OF SOLAR FLARES WITH A CONSTRAINED PEAK X-RAY FLUX

    SciTech Connect

    Bowen, Trevor A.; Testa, Paola; Reeves, Katharine K., E-mail: tbowen@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 58, Cambridge, MA 02138 (United States)

    2013-06-20

    We present an analysis of soft X-ray (SXR) and extreme-ultraviolet (EUV) observations of solar flares with an approximate C8 Geostationary Operational Environmental Satellite (GOES) class. Our constraint on peak GOES SXR flux allows for the investigation of correlations between various flare parameters. We show that the duration of the decay phase of a flare is proportional to the duration of its rise phase. Additionally, we show significant correlations between the radiation emitted in the flare rise and decay phases. These results suggest that the total radiated energy of a given flare is proportional to the energy radiated during the rise phase alone. This partitioning of radiated energy between the rise and decay phases is observed in both SXR and EUV wavelengths. Though observations from the EUV Variability Experiment show significant variation in the behavior of individual EUV spectral lines during different C8 events, this work suggests that broadband EUV emission is well constrained. Furthermore, GOES and Atmospheric Imaging Assembly data allow us to determine several thermal parameters (e.g., temperature, volume, density, and emission measure) for the flares within our sample. Analysis of these parameters demonstrate that, within this constrained GOES class, the longer duration solar flares are cooler events with larger volumes capable of emitting vast amounts of radiation. The shortest C8 flares are typically the hottest events, smaller in physical size, and have lower associated total energies. These relationships are directly comparable with several scaling laws and flare loop models.

  13. Commissioning of Angle Dispersive X-ray Diffraction Beamline on Indus-2

    SciTech Connect

    Sinha, A. K.; Sagdeo, Archna; Gupta, Pooja; Kumar, Ashok; Singh, M. N.; Gupta, R. K.; Kane, S. R.; Deb, S. K. [Indus Synchrotrons Utilization Division, Raja Ramanna Center for Advanced Technology, Indore 452013 (India)

    2011-07-15

    An Angle dispersive x-ray diffraction (ADXRD) beamline on bending magnet source of Indus-2 synchrotron (2.5 GeV, 300 mA) has been commissioned, for the study of single and polycrystalline samples. The beamline optics is based on vertically focusing Pt-coated pre and post mirrors and sagittal focusing Si (311) based double crystal monochromator. Experimental station consists of a six circle diffractometer equipped with scintillation detector and an image plate area detector for powder diffraction. XRD experiments have been performed to study single crystal and polycrystalline samples.

  14. Place of HgI2 energy-dispersive X-ray detectors

    NASA Astrophysics Data System (ADS)

    Dabrowski, A. J.; Huth, G. C.; Iwanczyk, J. S.; Kusmiss, J. H.; Barton, J. S.; Szymczyk, J. M.; Schnepple, W.; Lynn, R.

    After a review of solid-state conduction counters, in general, and of the history of mercuric iodide, in particular, the theory of operation of solid-state energy-dispersive HgI2 detectors is discussed. The main factors which limit energy resolution in solid state compound detectors are considered, including statistical fluctuations in charge generation, the window effect, trapping, inhomogeneities in the detector material, and electronic noise. Potential applications of room-temperature HgI2 X-ray fluorescence analysis with HgI2. Directions of current investigations are given.

  15. Processing and quantification of x-ray energy dispersive spectra in the Analytical Electron Microscope

    SciTech Connect

    Zaluzec, N.J.

    1988-08-01

    Spectral processing in x-ray energy dispersive spectroscopy deals with the extraction of characteristic signals from experimental data. In this text, the four basic procedures for this methodology are reviewed and their limitations outlined. Quantification, on the other hand, deals with the interpretation of the information obtained from spectral processing. Here the limitations are for the most part instrumental in nature. The prospects of higher voltage operation does not, in theory, present any new problems and may in fact prove to be more desirable assuming that electron damage effects do not preclude analysis. 28 refs., 6 figs.

  16. Determination of carrier yields for neutron activation analysis using energy dispersive X-ray spectrometry

    USGS Publications Warehouse

    Johnson, R.G.; Wandless, G.A.

    1984-01-01

    A new method is described for determining carrier yield in the radiochemical neutron activation analysis of rare-earth elements in silicate rocks by group separation. The method involves the determination of the rare-earth elements present in the carrier by means of energy-dispersive X-ray fluorescence analysis, eliminating the need to re-irradiate samples in a nuclear reactor after the gamma ray analysis is complete. Results from the analysis of USGS standards AGV-1 and BCR-1 compare favorably with those obtained using the conventional method. ?? 1984 Akade??miai Kiado??.

  17. WAVELENGTH MEASUREMENTS OF K TRANSITIONS OF OXYGEN, NEON, AND MAGNESIUM WITH X-RAY ABSORPTION LINES

    SciTech Connect

    Liao Jinyuan; Zhang Shuangnan [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Yao Yangsen, E-mail: zhangsn@ihep.ac.cn [Eureka Scientific, 2452 Delmer Street Suite 100, Oakland, CA 94602 (United States)

    2013-09-10

    Accurate atomic transition data are important in many astronomical research areas, especially for studies of line spectroscopy. Whereas transition data of He-like and H-like ions (i.e., ions in high-charge states) have been accurately calculated, the corresponding data of K transitions of neutral or low-ionized metal elements are still very uncertain. Spectroscopy of absorption lines produced in the interstellar medium (ISM) has been proven to be an effective way to measure the central wavelengths of these atomic transitions. In this work, we analyze 36 Chandra High Energy Transmission Grating observations to search for and measure the ISM absorption lines along sight lines to 11 low-mass X-ray binaries. We correct the Galactic rotation velocity to the rest frame for every observation and then use two different methods to merge all the corrected spectra to a co-added spectrum. However, the co-added spectra obtained by this method exhibit biases, toward to either observations with high counts or lines with high signal-to-noise ratios. We do a Bayesian analysis of several significantly detected lines to obtain the systematic uncertainty and the bias correction for other lines. Compared to previous studies, our results improve the wavelength accuracy by a factor of two to five and significantly reduce the systematic uncertainties and biases. Several weak transitions (e.g., 1s-2p of Mg IV and Mg V; 1s-3p of Mg III and Mg V) are also detected for the first time, albeit with low significance; future observations with improved accuracy are required to confirm these detections.

  18. X-ray Photon Correlation Spectroscopy: A New Probe of Short Wavelength Dynamics

    NASA Astrophysics Data System (ADS)

    Dierker, S. B.

    1996-03-01

    The new field of x-ray photon correlation spectroscopy (XPCS) offers an unprecedented opportunity to extend the range of length scales over which a material's low frequency dynamics can be studied down to interatomic spacings. The critical development which has now made XPCS a feasible technique is the high brightness of insertion devices at second and third generation synchrotron sources. In this talk, I will describe the principles of the XPCS technique and how it is practiced, as well as its potential use for a variety of important problems in the low frequency dynamics of condensed matter systems, such as complex fluids, glasses, surfaces, and metallic alloys. Illustrations will be drawn from our(Research done in collaboration with R. Pindak, R. M. Fleming, I. K. Robinson, L. Berman, G. Grubel, and D. L. Abernathy. S.B.D. supported by NSF DMR92-17956. I.K.R. supported by NSF MDR 93-15691. The NSLS is supported by DOE DE-AC02-76CH00016.) results(S. B. Dierker, R. Pindak, R. M. Fleming, I. K. Robinson, L. Berman, Phys. Rev. Lett. 75), 449 (1995). on using XPCS to study the Brownian motion of a gold colloid. We made small angle x-ray scattering measurements of the static structure factor of an optically opaque gold colloid dispersed in the viscous liquid glycerol. We discovered a novel effect due to photoemission induced charging of the gold colloid which could be suppressed by the addition of salt. We determined the dynamic correlation functions for the Brownian motion of the colloid particles at wavevectors between 10-3 <= q <= 10-2 Åwhich extends well beyond the range of visible light scattering. The resulting diffusion coefficient is very q dependent, scaling approximately as D(q) = D_o/S(q). The results of recent progress in using the Prototype Small Gap Undulator (PSGU) at beam line X13 at the NSLS will also be described. We(Research done in collaboration with L. Berman, Z. Yin, and E. Dufresne.) have achieved a coherent flux of > 10^10 photons/second in a `pink' beam at 3 keV by using a mirror to filter out the harmonics. This should be an excellent source for small angle XPCS measurements. The results of initial experiments conducted with the PSGU will be presented. The experiments were conducted at the wiggler beam line X25 and the PSGU beamline X13 at the NSLS and at the undulator beamline 9/ID10 (Troika) at the ESRF.

  19. Characterization of Japanese color sticks by energy dispersive X-ray fluorescence, X-ray diffraction and Fourier transform infrared analysis

    NASA Astrophysics Data System (ADS)

    Manso, M.; Valadas, S.; Pessanha, S.; Guilherme, A.; Queralt, I.; Candeias, A. E.; Carvalho, M. L.

    2010-04-01

    This work comprises the use of energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) techniques for the study of the composition of twentieth century traditional Japanese color sticks. By using the combination of analytical techniques it was possible to obtain information on inorganic and organic pigments, binders and fillers present in the sticks. The colorant materials identified in the sticks were zinc and titanium white, chrome yellow, yellow and red ochre, vermillion, alizarin, indigo, Prussian and synthetic ultramarine blue. The results also showed that calcite and barite were used as inorganic mineral fillers while Arabic gum was the medium used. EDXRF offered great potential for such investigations since it allowed the identification of the elements present in the sample preserving its integrity. However, this information alone was not enough to clearly identify some of the materials in study and therefore it was necessary to use XRD and FTIR techniques.

  20. Practical applications of energy dispersive X-ray microanalysis in diagnostic oral pathology

    SciTech Connect

    Daley, T.D.; Gibson, D. (Univ. of Western Ontario, London (Canada))

    1990-03-01

    Energy dispersive X-ray microanalysis is a powerful tool that can reveal the presence and relative quantities of elements in minute particles in biologic materials. Although this technique has been used in some aspects of dental research, it has rarely been applied to diagnostic oral pathology. The purpose of this paper is to inform practicing dentists and oral specialists about the diagnostic potential of this procedure by presenting three case reports. The first case involved the identification of flakes of a metallic material claimed by a 14-year-old girl to appear periodically between her mandibular molars. In the second case, a periodontist was spared a lawsuit when a freely mobile mass in the antrum of his patient was found to be a calcium-phosphorus compound not related to the periodontal packing that had been used. The third case involved the differential diagnosis of amalgam tattoo and graphite tattoo in a pigmented lesion of the hard palate mucosa. The results of the analyses were significant and indicate a role for this technique in the assessment of selected cases. Potential for wider use of energy dispersive X-ray microanalysis in diagnostic oral pathology exists as research progresses.

  1. Practical applications of energy dispersive X-ray microanalysis in diagnostic oral pathology.

    PubMed

    Daley, T D; Gibson, D

    1990-03-01

    Energy dispersive X-ray microanalysis is a powerful tool that can reveal the presence and relative quantities of elements in minute particles in biologic materials. Although this technique has been used in some aspects of dental research, it has rarely been applied to diagnostic oral pathology. The purpose of this paper is to inform practicing dentists and oral specialists about the diagnostic potential of this procedure by presenting three case reports. The first case involved the identification of flakes of a metallic material claimed by a 14-year-old girl to appear periodically between her mandibular molars. In the second case, a periodontist was spared a lawsuit when a freely mobile mass in the antrum of his patient was found to be a calcium-phosphorus compound not related to the periodontal packing that had been used. The third case involved the differential diagnosis of amalgam tattoo and graphite tattoo in a pigmented lesion of the hard palate mucosa. The results of the analyses were significant and indicate a role for this technique in the assessment of selected cases. Potential for wider use of energy dispersive X-ray microanalysis in diagnostic oral pathology exists as research progresses. PMID:2314858

  2. X-ray coherent scattering form factors of tissues, water and plastics using energy dispersion

    NASA Astrophysics Data System (ADS)

    King, B. W.; Landheer, K. A.; Johns, P. C.

    2011-07-01

    A key requirement for the development of the field of medical x-ray scatter imaging is accurate characterization of the differential scattering cross sections of tissues and phantom materials. The coherent x-ray scattering form factors of five tissues (fat, muscle, liver, kidney, and bone) obtained from butcher shops, four plastics (polyethylene, polystyrene, lexan (polycarbonate), nylon), and water have been measured using an energy-dispersive technique. The energy-dispersive technique has several improvements over traditional diffractometer measurements. Most notably, the form factor is measured on an absolute scale with no need for scaling factors. Form factors are reported in terms of the quantity x = ?-1sin (?/2) over the range 0.363-9.25 nm-1. The coherent form factors of muscle, liver, and kidney resemble those of water, while fat has a narrower peak at lower x, and bone is more structured. The linear attenuation coefficients of the ten materials have also been measured over the range 30-110 keV and parameterized using the dual-material approach with the basis functions being the linear attenuation coefficients of polymethylmethacrylate and aluminum.

  3. [Analysis of pine pollen by using FTIR, SEM and energy-dispersive X-ray analysis].

    PubMed

    Wang, Ya-min; Wang, Hong-jie; Zhang, Zhuo-yong

    2005-11-01

    Infrared spectroscopy (IR), scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDX) were used to analyze nutrients in four pine pollen powder samples. The IR fingerprints showed that each of the samples, pinus massoniana, pinus yunnanensis, pinus tabulaeformis, and pinus densiflora, respectively had its own characteristic infrared spectrum. Based on the difference of the relative intensity of those characteristic absorption peaks, the IR fingerprints can be used for the identification of the four kinds of pine pollen samples. The broken pollen of pinus was more easily to release nutritional components for the distinct difference IR fingerprints of natural and broken masson pine pollen samples. As a result of SEM, four kinds of pollen grains were oblong or subspheroidal in distal face and proximal face. The exine sculpture of the four kinds of samples were granulous and almost the same, but there was some difference of the size of pollen grains. The main morphologic change of the broken pollen was that the air bags were separated from pollen particles, and part of the main body of pollen particles was broken. The energy-dispersive X-ray analysis results showed that eleven elements, including Mg, Se, Si, Sr, P, S, Cl, K, Ca, Mn, and Fe, existed and the highest content in pollen of pinus was K element. The contents of trace elements were different in different kinds of pollen of pinus. The element intensity in broken masson pine pollen was distinctlyhigher than that innatural masson pine pollen. PMID:16499047

  4. Improved energy-dispersive X-ray scattering system based on polycapillary collimation and a Silicon Drift Detector

    Microsoft Academic Search

    C. Ozkan; C. Guazzoni; A. Castoldi; A. Bjeoumikhov

    2010-01-01

    We have developed a setup for low angle energy dispersive X-ray scattering measurement employing two key components: i) a Silicon Drift Detector (SDD) which can provide energy resolution close to Fano limit at fast processing times and ii) an X-ray collimator based on parallel polycapillary technology that allows angular resolution in the milli-radiant range. Combining these features an instrument has

  5. Sulfur Distribution in Bacteriorhodopsin from Multiple Wavelength Anomalous Diffraction Near the Sulfur KEdge with Synchrotron X-Ray Radiation

    Microsoft Academic Search

    Wolfgang Behrens; Harald Otto; Heinrich B. Stuhrmann; Maarten P. Heyn

    1998-01-01

    Bacteriorhodopsin contains nine sulfur atoms from the nine methionine residues. The distribution of these sulfur atoms in the projected density map was determined from x-ray diffraction experiments using multiple wavelength anomalous diffraction (MAD) at the sulfur K-edge (5.02Å) with synchrotron radiation. The experiments were performed with uniaxial samples of oriented purple membranes at room temperature and 86% relative humidity. For

  6. High-average-power, 100-Hz-repetition-rate, tabletop soft-x-ray lasers at sub-15-nm wavelengths

    NASA Astrophysics Data System (ADS)

    Reagan, Brendan A.; Berrill, Mark; Wernsing, Keith A.; Baumgarten, Cory; Woolston, Mark; Rocca, Jorge J.

    2014-05-01

    Efficient excitation of dense plasma columns at 100-Hz repetition rate using a tailored pump pulse profile produced a tabletop soft-x-ray laser average power of 0.1 mW at ? = 13.9 nm and 20 ?W at ? = 11.9 nm from transitions of Ni-like Ag and Ni-like Sn, respectively. Lasing on several other transitions with wavelengths between 10.9 and 14.7 nm was also obtained using 0.9-J pump pulses of 5-ps duration from a compact diode-pumped chirped pulse amplification Yb:YAG laser. Hydrodynamic and atomic plasma simulations show that the pump pulse profile, consisting of a nanosecond ramp followed by two peaks of picosecond duration, creates a plasma with an increased density of Ni-like ions at the time of peak temperature that results in a larger gain coefficient over a temporally and spatially enlarged space leading to a threefold increase in the soft-x-ray laser output pulse energy. The high average power of these compact soft-x-ray lasers will enable applications requiring high photon flux. These results open the path to milliwatt-average-power tabletop soft-x-ray lasers.

  7. Thermal and nonthermal phenomena in solar flare loops at 20 cm wavelength and in x rays. Technical report

    SciTech Connect

    Schmahl, E.J.; Kundu, M.R.; Landecker, P.B.; McKenzie, D.L.

    1983-12-15

    We present X-ray images from the P78-1 satellite for a long-lasting burst at 20-cm wavelength mapped with the Very Large Array on 19 May 1979 by Velusamy and Kundu (1981). The decimeter wave observations were originally interpreted in terms of two models, one invoking thermal electrons radiating at low harmonics of the gyrofrequency, and the other invoking mildly relativistic electrons emitting gyrosynchrotron radiation. If indeed the 20 cm source is thermal, it should also be visible in soft X rays while if it is nonthermal, the soft X-ray emission should be weak or spatially or temporally distinct from the 20 cm burst. We find that only one of the three 20 cm sources was approximately co-spatial with the soft X-ray source, and that is was only partially thermal. The 20 cm burst is therefore primarily decimeter type IV emission from mildly relativistic electrons of the post-flare phase. The long lifetime ( or approx 2 hr) and smooth temporal variation of the burst belie its nonthermal nature and suggest continuous acclerations as well as long term storage of energetic electrons.

  8. 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.

  9. Energy-dispersive X-ray fluorescence analysis as a rapid method for identifying tephras

    NASA Astrophysics Data System (ADS)

    Cormie, A. B.; Nelson, D. E.

    1983-03-01

    The use of energy-dispersive X-ray fluorescence analysis (XES) for the routine identification of three tephras (Mazama, Bridge River, Mount St. Helens Yn) commonly found in archeological sites in British Columbia has been investigated. Researchers have often assumed that chemical analysis of bulk samples of glass separates would be hampered by contamination and weathering effects. Our results indicate that XES of bulk glass separates provides a very reliable method for rapidly identifying the three tephras in question, even with a very simple sample preparation. This should enable persons not skilled in geology or in tephrochronology to collect and to identify samples of these tephras. Finally, as a part of the study, similar measurements were made on the separated glass portions of these three tephras and of three others (Glacier Peak B and G, White River) from northwest North America. The results suggest that this method may provide tephrochronologists with a useful additional tool for studying tephras in other regions.

  10. Evaluation on determination of iodine in coal by energy dispersive X-ray fluorescence

    USGS Publications Warehouse

    Wang, B.; Jackson, J.C.; Palmer, C.; Zheng, B.; Finkelman, R.B.

    2005-01-01

    A quick and inexpensive method of relative high iodine determination from coal samples was evaluated. Energy dispersive X-ray fluorescence (EDXRF) provided a detection limit of about 14 ppm (3 times of standard deviations of the blank sample), without any complex sample preparation. An analytical relative standard deviation of 16% was readily attainable for coal samples. Under optimum conditions, coal samples with iodine concentrations higher than 5 ppm can be determined using this EDXRF method. For the time being, due to the general iodine concentrations of coal samples lower than 5 ppm, except for some high iodine content coal, this method can not effectively been used for iodine determination. More work needed to meet the requirement of determination of iodine from coal samples for this method. Copyright ?? 2005 by The Geochemical Society of Japan.

  11. Structural study of silica particle dispersions by ultra-small-angle x-ray scattering

    NASA Astrophysics Data System (ADS)

    Konishi, Toshiki; Ise, Norio; Matsuoka, Hideki; Yamaoka, Hitoshi; Sogami, Ikuo S.; Yoshiyama, Tsuyoshi

    1995-02-01

    An ultra-small-angle x-ray-scattering study showed several orders of Bragg diffraction for an aqueous colloidal silica dispersion in a vertically held glass capillary, the first peak being at 150''. The same profile was observed when the capillary was rotated around its axis by (60×m)° (where m is an integer). A different profile was found at (30+60×m)° with the first peak at 85''. This showed that a bcc lattice was maintained with the (110) plane parallel to the capillary wall and with a lattice constant =3000 Å, d110=2100 Å, and d020=1500 Å. The closest interparticle distance (2Dexp) was 2600 Å while the average distance from the overall concentration (2D0) was 2900 Å, indicating the non-space-filling nature of the crystal.

  12. Angle-Dispersive X-ray Diffraction Study of Energetic Materials

    NASA Astrophysics Data System (ADS)

    Gump, Jared; Peiris, Suhithi

    2004-03-01

    Determining thermodynamic properties of energetic materials is important to the United States Navy for predicting the performance of new energetic formulations. This study uses angle dispersive x-ray diffraction performed at Cornell University's High Energy Synchrotron Source to obtain several isothermal equations of state of energetic materials, such as HMX and CL-20. Both non-hydrostatic and hydrostatic conditions were examined at room temperature. Pressures of up to 6GPa were achieved using diamond anvil cells. The bulk modulus and its first pressure derivative were determined by fitting the data to the Birch-Murnaghan equation of state formalism. Experimental data will be compared to ab-initio HF calculations and MD simulations.

  13. Scanning electron microscope/energy dispersive x ray analysis of impact residues on LDEF tray clamps

    NASA Technical Reports Server (NTRS)

    Bernhard, Ronald P.; Durin, Christian; Zolensky, Michael E.

    1992-01-01

    To better understand the nature of particulates in low-Earth orbit (LEO), and their effects on spacecraft hardware, we are analyzing residues found in impacts on the Long Duration Exposure Facility (LDEF) tray clamps. LDEF experiment trays were held in place by 6 to 8 chromic-anodized aluminum (6061-T6) clamps that were fastened to the spacecraft frame using three stainless steel hex bolts. Each clamp exposed an area of approximately 58 sq cm (4.8 cm x 12.7 cm x .45 cm, minus the bolt coverage). Some 337 out of 774 LDEF tray clamps were archived at JSC and are available through the Meteoroid & Debris Special Investigation Group (M&D SIG). Optical scanning of clamps, starting with Bay/Row A01 and working toward H25, is being conducted at JSC to locate and document impacts as small as 40 microns. These impacts are then inspected by Scanning Electron Microscopy/Energy Dispersive X-ray Analysis (SEM/EDXA) to select those features which contain appreciable impact residue material. Based upon the composition of projectile remnants, and using criteria developed at JSC, we have made a preliminary discrimination between micrometeoroid and space debris residue-containing impact features. Presently, 13 impacts containing significant amounts of unmelted and semi-melted micrometeoritic residues were forwarded to Centre National d'Etudes Spatiales (CNES) in France. At the CNES facilities, the upgraded impacts were analyzed using a JEOL T330A SEM equipped with a NORAN Instruments, Voyager X-ray Analyzer. All residues were quantitatively characterized by composition (including oxygen and carbon) to help understand interplanetary dust as possibly being derived from comets and asteroids.

  14. EDAX Compact Detector Unit EDAX detector is used for advanced materials characterization of energy dispersive X-ray microanalysis (EDS).

    E-print Network

    EDAX Compact Detector Unit EDAX© detector is used for advanced materials characterization of energy dispersive X-ray microanalysis (EDS). In 1992, EDAX introduced the Compact Detector Unit (CDU), a major. It is available with 10mm2 or 30mm2 detector crystals. #12;Electron Count by EDAX detector (8/16/05) 0 500 1000

  15. Phonon dispersion of oriented DNA by inelastic x-ray scattering

    NASA Astrophysics Data System (ADS)

    Krisch, M.; Mermet, A.; Grimm, H.; Forsyth, V. T.; Rupprecht, A.

    2006-06-01

    Films of oriented deoxyribonucleic acid (DNA), prepared by the wet spinning method, have been studied using inelastic x-ray scattering. Spectra were recorded within the range of energy transfers -30dispersion and damping of modes having displacements with nonzero projections onto Q , i.e., essentially the compression waves traveling along the helical axis. The longitudinal speed of sound resulting from the sinusoidal dispersion varies only weakly with conformation. Our sound speed values are compared to results from Brillouin spectroscopy. The dispersion curves exhibit a minimum at about the inverse rise per residue, which—together with strong elastic scattering—reflect the large degree of disorder. Overdamping of the modes is observed for Q>5nm-1 . The possibility that the observed large damping parameters are due to several contributing modes is discussed in terms of a simple model calculation for an idealized double helix. Whereas the quasicrystalline approximation for an effective disordered chain could well describe the sinusoidal dispersion, it fails to reproduce the observed damping by one order of magnitude. Our results indicate that the high-frequency dynamics of DNA is liquidlike and is most appropriately described by instantaneous normal modes of short correlation length.

  16. X-ray Scattering Measurements of Particle Orientation in a Sheared Polymer/Clay Dispersion

    SciTech Connect

    Pujari, Saswati; Dougherty, Leah; Mobuchon, Christoph; Carreau, Pierre J.; Heuzey, Marie-Claude; Burghardt, Wesley R. (Ecole); (NWU); (Ecole)

    2012-01-20

    We report steady and transient measurements of particle orientation in a clay dispersion subjected to shear flow. An organically modified clay is dispersed in a Newtonian polymer matrix at a volume fraction of 0.02, using methods previously reported by Mobuchon et al. (Rheol Acta 46: 1045, 2007). In accord with prior studies, mechanical rheometry shows yield stress-like behavior in steady shear, while time dependent growth of modulus is observed following flow cessation. Measurements of flow-induced orientation in the flow-gradient plane of simple shear flow using small-angle and wide-angle X-ray scattering (SAXS and WAXS) are reported. Both SAXS and WAXS reveal increasing particle orientation as shear rate is increased. Partial relaxation of nanoparticle orientation upon flow cessation is well correlated with time-dependent changes in complex modulus. SAXS and WAXS data provide qualitatively similar results; however, some quantitative differences are attributed to differences in the length scales probed by these techniques.

  17. Soft X-ray emissions, meter-wavelength radio bursts, and particle acceleration in solar flares

    NASA Technical Reports Server (NTRS)

    Cane, H. V.; Reames, D. V.

    1988-01-01

    A detailed study of the relationship between metric radio bursts and soft X-ray flares has been made using an extensive data set covering 15 yr. It is found that type IV emission is mainly associated with long-duration 1-8 A events that are known to be well associated with coronal mass ejections. In contrast, type II and type III bursts originate primarily in impulsive soft X-ray events that are not necessarily accompanied by mass ejection. Strong type III bursts, in particular, appear to occur only in association with relatively impulsive flares. It is suggested that coronal shocks responsible for type II bursts are blast waves generated in impulsive energy releases.

  18. Total reflection X-ray fluorescence and energy-dispersive X-ray fluorescence analysis of runoff water and vegetation from abandoned mining of Pb Zn ores

    NASA Astrophysics Data System (ADS)

    Marques, A. F.; Queralt, I.; Carvalho, M. L.; Bordalo, M.

    2003-12-01

    The present work reports on the heavy metal content: Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd and Pb in running waters and vegetation around abandoned mining areas. Two species of mosses ( Dicranum sp. and Pleurocarpus sp.) and three different species of wild grass ( Bromus sp., Rumex sp. and Pseudoavena sp.) growing on the surrounding areas of old lead-zinc mines (Aran Valley, Pyrenees, NE Spain) have been analyzed. Both water and vegetation were collected in two different sampling places: (a) near the mine gallery water outlets and (b) on the landfill close to the abandoned mineral concentration factories. For the heavy metal content determination, two different techniques were used: total reflection X-ray fluorescence for water analysis and energy-dispersive X-ray fluorescence for vegetation study. Surface waters around mine outlets exhibit anomalous content of Co, Ni, Zn, Cd. Stream waters running on mining landfills exhibit higher Cu, Zn, Cd and Pb than those of the waters at the mine gallery outlets. The results allow us to assess the extent of the environmental impact of the mining activities on the water quality. The intake of these elements by vegetation was related with the sampling place, reflecting the metal water content and the substrate chemistry. Accumulation of metals in mosses is higher than those exhibited in wild grasses. Furthermore, different levels of accumulation were found in different wild grass. Rumex sp. presented the lowest metal concentrations, while Pseudoavena sp. reported the highest metal content.

  19. Sulfur speciation in hydrous experimental glasses of varying oxidation state - Results from measured wavelength shifts of sulfur X-rays

    NASA Technical Reports Server (NTRS)

    Carroll, Michael R.; Rutherford, Malcolm J.

    1988-01-01

    The focusing geometry of an electron microprobe has been used to measure the wavelength shifts of sulfur X-rays from hydrous experimental melts synthesized at oxygen fugacities that range from near the iron-wustite buffer to the magnetite-hermatite buffer. It is found that the proportion of dissolved sulfur which is present as sulfate increases with increasing oxygen fugacity. It is noted that in natural melts that have equilibrated at or below fayalite-magnetite-quartz values of +1, sulfur is probably present mainly as S(2-).

  20. THIN FILM DENSITY DETERMINATION BY MULTIPLE RADIATION ENERGY DISPERSIVE X-RAY REFLECTIVITY

    Microsoft Academic Search

    D. Windover; E. Barnat; J. Y. Kim; M. Nielsen; T.-M. Lu; A. Kumar; H. Bakhru; C. Jin; S. L. Lee

    X-Ray Reflectivity provides a non-destructive technique for measuring density in thin films. A conventional laboratory, Bragg-Brentano-geometry diffractometer was employed to show the generalized feasibility of this technique. X-ray tubes with Cr, Cu and MO targets were used to provide a large overlap of energies for density fitting. X-Ray tube alignment and sample alignment were explored to find a self-consistent measurement

  1. Portable energy dispersive X-ray fluorescence spectrometry and PIXE for elemental quantification of historical paper documents

    NASA Astrophysics Data System (ADS)

    Manso, M.; Reis, M. A.; Candeias, J.; Carvalho, M. L.

    2013-03-01

    We have used a portable energy dispersive X-ray fluorescence spectrometer based on a silicon drift detector for elemental quantification of a historical paper document. Quantitative calculations were carried out using the WinAxil software package. In order to minimize matrix effects and to accurately reflect the conditions under which quantification is usually performed, the fundamental parameters package with a known paper samples was used. Reference values for paper samples were obtained through a set of a particle induced X-ray emission techniques.

  2. TeV source HESS J1804-216 in X-rays and other wavelengths

    E-print Network

    O. Kargaltsev; G. G. Pavlov; G. P. Garmire

    2007-01-03

    The field of the extended TeV source HESS J1804-216 was serendipitously observed with the Chandra ACIS detector. The data reveal several X-ray sources within the bright part of HESS J1804-216. The brightest of these objects, CXOU J180432.4-214009, which has been also detected with Swift and Suzaku, is consistent with being a point-like source, with the 0.3-7 keV flux of (1.7\\pm0.2)\\times10^{-13} ergs s^{-1} cm^{-2}. Its hard and strongly absorbed spectrum can be fitted by the absorbed power-law model with the best-fit photon index of 0.45 and hydrogen column density of 4\\times10^{22} cm^{-2}, both with large uncertainties due to the strong correlation between these parameters. A search for pulsations resulted in a 106 s period candidate, which however has a low significance of 97.9%. We found no infrared-optical counterparts for this source. The second brightest source, CXOU J180441.9-214224, which has been detected with Suzaku, is either extended or multiple, with the flux of about 10^{-13} ergs cm^{-2} s^{-1}. We found a nearby M dwarf within the X-ray source extension, which could contribute a fraction of the observed X-ray flux. The remaining sources are very faint (HESS J1804-216 remains elusive. The possibility that HESS J1804-216 is powered by the relativistic wind from the young pulsar B1800-21, located at a distance of about 10 pc from the TeV source, still remains a more plausible option.

  3. Elemental analysis of mining wastes by energy dispersive X-ray fluorescence (EDXRF)

    NASA Astrophysics Data System (ADS)

    Gonzalez-Fernandez, O.; Queralt, I.; Carvalho, M. L.; Garcia, G.

    2007-08-01

    An energy dispersive X-ray fluorescence (EDXRF) tri-axial geometry experimental spectrometer has been employed to determine the concentrations of 13 different elements (K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr and Pb) in mine wastes from different depths of two mine tailings from the Cartagena-La Union (Spain) mining district. The elements were determined and quantified using the fundamental parameters method. The concentrations of Cr, Ni, Cu, Zn and Pb were compared to the values from the European and Spanish legislation to evaluate the environmental risk and to classify the wastes as inert wastes or as wastes that have to be control land-filled. The results obtained demonstrate that these wastes can be considered as inert for the considered elements, apart from the concentration levels of Zn and Pb. Whilst Zn slightly overpasses the regulatory levels, Pb mean value exceeds three to six times the value to be considered as Class I potential land-filling material.

  4. An X-ray absorption spectroscopy study of an oxide dispersion strengthened steel

    NASA Astrophysics Data System (ADS)

    Pouchon, M. A.; Kropf, A. J.; Froideval, A.; Degueldre, C.; Hoffelner, W.

    2007-05-01

    Oxide dispersion strengthened (ODS) steels are being investigated as possible structural material for components of future nuclear power plants. The dispersoids in the matrix (yttria particles) serve as pinning points for moving dislocations, and thereby improve the creep behavior of the material. Depending on the product, the dimension of the particles is in the range from a few nm up to 100 nm. The material properties depend on the size distribution. It is also expected that other parameters of the dispersoids may influence the materials behavior. An extended X-ray absorption fine structure (EXAFS) study has been conducted on PM2000 (ferritic ODS steel) samples, in order to determine the structure of the yttria inclusions. A PM2000 sample, which had been irradiated with He ions of 1.5 MeV up to a matrix-damage of ˜1 displacement per atom (dpa) in a surface layer of 2.7 ?m in depth was measured. A multi angle implantation was performed, in order to avoid damage peaks as function of depth. A direct comparison of the EXAFS spectra and of the Fourier transformations shows no major difference between the irradiated samples and the non-irradiated one. Therefore any potential radiation induced damage or phase transformation of the dispersoids must be minor, which indicates good radiation stability under the given circumstances.

  5. 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.

  6. Investigation of the composition of historical and modern Italian papers by energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), and scanning electron microscopy energy dispersive spectrometry (SEM-EDS).

    PubMed

    Manso, Marta; Carvalho, Maria Luisa; Queralt, Ignacio; Vicini, Silvia; Princi, Elisabetta

    2011-01-01

    In this work, a study concerning the composition of Italian papers from the seventeenth to the twentieth centuries was carried out using energy dispersive X-ray fluorescence spectrometry (EDXRF), X-ray diffraction (XRD), and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS). The analyzed samples consisted of papers employed for drawing, writing, printing, and absorbance. Observations carried out by SEM magnified the typical paper morphology. EDXRF in combination with XRD and SEM-EDS allowed the determination of calcite, gypsum, kaolin, talc, magnesite, and dolomite, used as fillers in the production of the papers studied herein. The inks present in the handwritten and printed papers, investigated by SEM-EDS and ?-EDXRF, were synthetic, Fe based, and iron gall inks. PMID:21211154

  7. The Subaru-XMM-Newton Deep Survey (SXDS) VIII.: Multi-wavelength Identification, Optical/NIR Spectroscopic Properties, and Photometric Redshifts of X-ray Sources

    E-print Network

    Akiyama, Masayuki; Watson, Mike G; Furusawa, Hisanori; Takata, Tadafumi; Simpson, Chris; Morokuma, Tomoki; Yamada, Toru; Ohta, Kouji; Iwamuro, Fumihide; Yabe, Kiyoto; Tamura, Naoyuki; Moritani, Yuuki; Takato, Naruhisa; Kimura, Masahiko; Maihara, Toshinori; Dalton, Gavin; Lewis, Ian; Lee, Hanshin; Lake, Emma Curtis; Macaulay, Edward; Clarke, Frazer; Silverman, John D; Croom, Scott; Ouchi, Masami; Hanami, Hitoshi; Tello, J Diaz; Yoshikawa, Tomohiro; Fujishiro, Naofumi; Sekiguchi, Kazuhiro

    2015-01-01

    We report the multi-wavelength identification of the X-ray sources found in the Subaru-XMM-Newton Deep Survey (SXDS) using deep imaging data covering the wavelength range between the far-UV to the mid-IR. We select a primary counterpart of each X-ray source by applying the likelihood ratio method to R-band, 3.6micron, near-UV, and 24micron source catalogs as well as matching catalogs of AGN candidates selected in 1.4GHz radio and i'-band variability surveys. Once candidates of Galactic stars, ultra-luminous X-ray sources in a nearby galaxy, and clusters of galaxies are removed there are 896 AGN candidates in the sample. We conduct spectroscopic observations of the primary counterparts with multi-object spectrographs in the optical and NIR; 65\\% of the X-ray AGN candidates are spectroscopically-identified. For the remaining X-ray AGN candidates, we evaluate their photometric redshift with photometric data in 15 bands. Utilising the multi-wavelength photometric data of the large sample of X-ray selected AGNs, w...

  8. X-Rays

    NSDL National Science Digital Library

    This problem set is designed to test students' understanding of x-rays. Students are given wavelengths and asked to calculate minimum potential energy, radiation frequency, and whether or not the mineral can be used as a radiation filter. They are also asked to determine the 2-theta for different crystal face x-ray diffractions given cell edge length and radiation wavelength.

  9. Polarity characterization by anomalous x-ray dispersion of ZnO films and GaN lateral polar structures

    NASA Astrophysics Data System (ADS)

    Shelton, Christopher T.; Sachet, Edward; Paisley, Elizabeth A.; Hoffmann, Marc P.; Rajan, Joseph; Collazo, Ramón; Sitar, Zlatko; Maria, Jon-Paul

    2014-01-01

    We demonstrate the use of anomalous x-ray scattering of constituent cations at their absorption edge, in a conventional Bragg-Brentano diffractometer, to measure absolutely and quantitatively the polar orientation and polarity fraction of unipolar and mixed polar wurtzitic crystals. In one set of experiments, the gradual transition between c+ and c- polarity of epitaxial ZnO films on sapphire as a function of MgO buffer layer thickness is monitored quantitatively, while in a second experiment, we map the polarity of a lateral polar homojunction in GaN. The dispersion measurements are compared with piezoforce microscopy images, and we demonstrate how x-ray dispersion and scanning probe methods can provide complementary information that can discriminate between polarity fractions at a material surface and polarity fractions averaged over the film bulk.

  10. Application of the focusing x-ray spectrograph with crossed dispersion to investigations of X pinch plasmas

    SciTech Connect

    Pikuz, S.A.; Song, B.M.; Shelkovenko, T.A.; Chandler, K.M.; Mitchell, M.D.; Hammer, D.A. [Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853 (United States)

    2004-10-01

    A new focusing spectrograph configuration with crossed dispersion (FSCD) has been developed for use in X pinch experiments. This device solves the problem in a crystal spectrograph of the overlapping of reflected radiation in many orders. The x-ray radiation from a small source is dispersed by a transmission grating before it reaches the Bragg reflector (mica crystal). A large aperture (10 mmx10 mm), 0.5 {mu}m period gold transmission grating was made on a 0.5 {mu}m thick Si{sub 3}N{sub 4} substrate and combined with spherically bent mica crystals with radii of curvature of 100 mm or 186 mm. Results of FSCD application to plasma experiments with X pinch x-ray sources is presented.

  11. The Subaru-XMM-Newton Deep Survey (SXDS) VIII. Multi-wavelength identification, optical/NIR spectroscopic properties, and photometric redshifts of X-ray sources†

    NASA Astrophysics Data System (ADS)

    Akiyama, Masayuki; Ueda, Yoshihiro; Watson, Mike G.; Furusawa, Hisanori; Takata, Tadafumi; Simpson, Chris; Morokuma, Tomoki; Yamada, Toru; Ohta, Kouji; Iwamuro, Fumihide; Yabe, Kiyoto; Tamura, Naoyuki; Moritani, Yuuki; Takato, Naruhisa; Kimura, Masahiko; Maihara, Toshinori; Dalton, Gavin; Lewis, Ian; Lee, Hanshin; Curtis Lake, Emma; Macaulay, Edward; Clarke, Frazer; Silverman, John D.; Croom, Scott; Ouchi, Masami; Hanami, Hitoshi; Díaz Tello, Jorge; Yoshikawa, Tomohiro; Fujishiro, Naofumi; Sekiguchi, Kazuhiro

    2015-07-01

    We report on the multi-wavelength identification of the X-ray sources found in the Subaru-XMM-Newton Deep Survey (SXDS) using deep imaging data covering the wavelength range between the far-UV and mid-IR (MIR). We select a primary counterpart of each X-ray source by applying the likelihood ratio method to R-band, 3.6 ?m, near-UV, and 24 ?m source catalogs as well as matching catalogs of active galactic nucleus (AGN) candidates selected in 1.4 GHz radio and i '-band variability surveys. Once candidates for Galactic stars, ultra-luminous X-ray sources in a nearby galaxy, and clusters of galaxies are removed there are 896 AGN candidates in the sample. We conduct spectroscopic observations of the primary counterparts with multi-object spectrographs in the optical and NIR; 65% of the X-ray AGN candidates are spectroscopically identified. For the remaining X-ray AGN candidates, we evaluate their photometric redshift with photometric data in 15 bands. Utilizing the multi-wavelength photometric data of the large sample of X-ray-selected AGNs, we evaluate the stellar masses, M*, of the host galaxies of the narrow-line AGNs. The distribution of the stellar mass is remarkably constant from z = 0.1 to 4.0. The relation between M* and 2-10 keV luminosity can be explained with strong cosmological evolution of the relationship between the black hole mass and M*. We also evaluate the scatter of the UV-MIR spectral energy distribution (SED) of the X-ray AGNs as a function of X-ray luminosity and absorption by the nucleus. The scatter is compared with galaxies which have redshift and stellar mass distribution matched with the X-ray AGN. The UV-NIR (near-IR) SEDs of obscured X-ray AGNs are similar to those of the galaxies in the matched sample. In the NIR-MIR range, the median SEDs of X-ray AGNs are redder, but the scatter of the SEDs of the X-ray AGN broadly overlaps that of the galaxies in the matched sample.

  12. Cryogenic microcalorimeters for high-resolution energy-dispersive x-ray spectrometry

    Microsoft Academic Search

    Godehard Angloher; Michael Altmann; Matthias Buehler; Franz von Feilitzsch; Theo Hertrich; Paul Hettl; Jens Hoehne; Michael Huber; Josef Jochum; Rudolf Moessbauer; Johann Schnagl; Stefanie Waenninger

    1999-01-01

    We are developing both superconducting tunnel junctions and phase transition thermometers for high resolution x-ray spectroscopy. A resolution of 12 eV has been achieved for aluminum tunnel junctions when irradiated by 5.9 keV x-rays. These devices show linear energy response in the range between 200 eV and 6.5 keV. Phase transition thermometers consisting of an iridium\\/gold bi-layer and a gold

  13. Selenium derivatization and crystallization of DNA and RNA oligonucleotides for X-ray crystallography using multiple anomalous dispersion

    Microsoft Academic Search

    Nicolas Carrasco; Yuri Buzin; Elizabeth Tyson; Elizer Halpert; Zhen Huang

    2004-01-01

    We report here the solid phase synthesis of RNA and DNA oligonucleotides containing the 2¢-selenium functionality for X-ray crystallography using multiwavelength anomalous dispersion. We have synthesized the novel 2¢-methylseleno cytidine phosphoramidite and improved the accessibility of the 2¢-methylseleno uridine phosphoramidite for the synthesis of many selenium-derivatized DNAs and RNAs in large scales. The yields of coupling these Se-nucleoside phosphoramidites into

  14. Backscattered electron imaging and energy-dispersive X-ray studies of water-treed polymeric insulation

    Microsoft Academic Search

    P. Y. Timbrell; A. Bulinski; S. S. Bamji; J. Densley

    1990-01-01

    The backscattered-electron imaging mode in a scanning electron microscope has been used to detect and image water trees in electrically stressed cross-linked polyethylene (XLPE) insulation. The location and distribution of inorganic contaminants, such as Cu or Cl, within the water-treed regions of the insulation were revealed using backscattered-electron imaging. Energy-dispersive X-ray (EDX) spectroscopy and mapping were subsequently used to ascertain

  15. Probing Heterogeneous Chemistry of Individual Atmospheric Particles Using Scanning Electron Microscopy and Energy-Dispersive X-ray Analysis

    Microsoft Academic Search

    Brenda J. Krueger; Vicki H. Grassian; Martin J. Iedema; James P. Cowin; Alexander Laskin

    2003-01-01

    In this paper, we demonstrate the utility of single-particle analysis to investigate the chemistry of isolated, individual particles of atmospheric relevance such as NaCl, sea salt, CaCO3, and SiO2. A variety of state-of-th-art scanning electron microscopy techniques, including environmental scanning electon microscopy and computer-controlled scanning electron microscopy\\/energy-dispersive X-ray analysis, were utilized for monitoring and quantifying phase transitions of individual particles,

  16. Line-coincidence schemes for producing laser action at soft-x-ray wavelengths

    SciTech Connect

    Chapline, G.F.

    1983-01-12

    Line-coincidence schemes for producing laser action in the wavelength regime 100-30A are reviewed. Schemes involving pumping of 2..-->..4 transitions in neon-like ions are singled out as particularly attractive.

  17. Direct analysis of human blood (mothers and newborns) by energy dispersive X-ray fluorescence.

    PubMed

    Custódio, P J; Carvalho, Maria Luisa; Nunes, F; Pedroso, S; Campos, A

    2005-01-01

    This work is an application of energy dispersive X-ray fluorescence (EDXRF) as analytical technique for trace element determination in human tissues. Potassium (K), calcium (Ca), iron (Fe), copper (Cu), zinc (Zn), bromine (Br), rubidium (Rb) and lead (Pb) were determined directly in blood samples from 66 mothers at delivery after full-term pregnancies. The corresponding 66 cord-blood samples of the newborns were also analysed, in order to find element correlations between maternal and newborn blood at birth. The studied samples were obtained from mothers aged between 15 and 39 years old, the gestational age being between 35 and 41 weeks and the newborns' weight between 2.310 and 4.310 kg. Samples were lyophilised and analysed without any chemical treatment. Very low levels of Pb were found both in maternal and fetal cord blood samples. Cu values ranged from 3 to 13 microg g-1, both for mothers and children. A correlation between Cu and Fe concentrations in maternal and fetal cord blood was found. Zn is considered as one of the key elements in newborn health. Concentrations between 10 and 40 microg g-1 were measured. A positive correlation between Br levels in mothers and children was observed. Positive correlations for mothers were observed between Zn and Rb as well as K and Fe. The corresponding correlations in fetal cord blood samples were not observed, however positive correlations were found between Ca and K; Cu and Fe. The mean concentrations for each element were similar in maternal and in fetal cord blood, except for Cu and Zn, being higher in maternal samples. No correlations between element concentrations and pathologies of the mothers were observed. PMID:16325530

  18. THE SAP3 COMPUTER PROGRAM FOR QUANTITATIVE MULTIELEMENT ANALYSIS BY ENERGY DISPERSIVE X-RAY FLUORESCENCE

    SciTech Connect

    Nielson,, K. K.; Sanders,, R. W.

    1982-04-01

    SAP3 is a dual-function FORTRAN computer program which performs peak analysis of energy-dispersive x-ray fluorescence spectra and then quantitatively interprets the results of the multielement analysis. It was written for mono- or bi-chromatic excitation as from an isotopic or secondary excitation source, and uses the separate incoherent and coherent backscatter intensities to define the bulk sample matrix composition. This composition is used in performing fundamental-parameter matrix corrections for self-absorption, enhancement, and particle-size effects, obviating the need for specific calibrations for a given sample matrix. The generalized calibration is based on a set of thin-film sensitivities, which are stored in a library disk file and used for all sample matrices and thicknesses. Peak overlap factors are also determined from the thin-film standards, and are stored in the library for calculating peak overlap corrections. A detailed description is given of the algorithms and program logic, and the program listing and flow charts are also provided. An auxiliary program, SPCAL, is also given for use in calibrating the backscatter intensities. SAP3 provides numerous analysis options via seventeen control switches which give flexibility in performing the calculations best suited to the sample and the user needs. User input may be limited to the name of the library, the analysis livetime, and the spectrum filename and location. Output includes all peak analysis information, matrix correction factors, and element concentrations, uncertainties and detection limits. Twenty-four elements are typically determined from a 1024-channel spectrum in one-to-two minutes using a PDP-11/34 computer operating under RSX-11M.

  19. A method for forward energy-dispersive X-ray fluorescence analysis of thin and intermediate samples

    NASA Astrophysics Data System (ADS)

    Cesareo, Roberto; Gigante, Giovanni E.; Hanson, Albert L.

    1998-11-01

    The usefulness of forward geometry in Energy Dispersive X-Ray Fluorescence (EDXRF) analysis has been investigated both experimentally and theoretically. This work relates to milli- and micro-beams, which limits this work to tightly collimated incident X-ray beams (<1 mm). The use of forward geometry also limits the targets to be of thin and intermediate thickness. The advantages and the peculiarities of using a forward geometry for XRF are discussed. Forward X-Ray Fluorescence (FXRF) has features including: (a) high geometrical efficiencies when using tightly collimated primary beams; (b) a minimisation in the uncertainty in the interaction volume; (c) a sample thickness at which the production of characteristic X rays is maximised; and (d) a filtering action by intermediate thickness samples resulting in an enhancement of the sensitivity for higher atomic number elements with respect to lower atomic number elements. For thin and intermediate thickness samples simultaneous forward and backward geometry XRF can be used to correct for self-absorption effect.

  20. RF undulator for compact X-ray SASE source of variable wavelength

    SciTech Connect

    Kuzikov, S. V.; Hirshfield, J. L.; Jiang, Y.; Marshall, T. C.; Vikharev, A. A. [Institute of Applied Physics, 46 Ulyanov St., Nizhny Novgorod, 603950 (Russian Federation) and Omega-P, Inc., New Haven, CT (United States); Yale University, New Haven, CT (United States) and Omega-P, Inc., New Haven, CT (United States); Yale University, New Haven, CT (United States); Omega-P, Inc., New Haven, CT (United States) and Columbia University, New York, NY (United States); Yale University, New Haven, CT (United States)

    2012-12-21

    A room-temperature RF undulator, fed by Ka-band radiation and intended to produce {approx}1 nm wavelength radiation using moderate energy electrons, is considered. The necessary electron bunches with energy 0.2-1 GeV could be produced by petawatt laser pulses injected into plasma bubbles.

  1. The application of a microstrip gas counter to energy-dispersive x-ray fluorescence analysis

    SciTech Connect

    Veloso, J.F.C.A.; Santos, J.M.F. dos; Conde, C.A.N. [Univ. de Coimbra (Portugal). Dept. de Fisica; Morgado, R.E. [Los Alamos National Lab., NM (United States)

    1996-07-01

    Performance characteristics of a microstrip gas counter operated as a x-ray fluorescence spectrometer are reported. Gas amplification as a function of microstrip anode-cathode voltage was measured, and the breakdown threshold voltage was determined in pure xenon. The detector temporal stability and the effect of gas purity were assessed. Energy resolution and linearity, detection efficiency, and uniformity of spatial response in the 2- to 60-keV x-ray energy range were determined from the pulse-height distributions of the fluorescence x-ray spectra induced in a variety of single- and multi-element sample materials. Energy resolution similar to conventional proportional counters was achieved at 6 keV.

  2. New reference and test materials for the characterization of energy dispersive X-ray spectrometers at scanning electron microscopes.

    PubMed

    Rackwitz, Vanessa; Krumrey, Michael; Laubis, Christian; Scholze, Frank; Hodoroaba, Vasile-Dan

    2015-04-01

    Checking the performance of energy dispersive X-ray spectrometers as well as validation of the results obtained with energy dispersive X-ray spectrometry (EDX) at a scanning electron microscope (SEM) involve the use of (certified) reference and dedicated test materials. This paper gives an overview on the test materials mostly employed by SEM/EDX users and accredited laboratories as well as on those recommended in international standards. The new BAM reference material EDS-CRM, which is currently in the process of certification, is specifically designed for the characterization of EDS systems at a SEM through calibration of the spectrometer efficiency in analytical laboratories in a simple manner. The certification of the spectra by means of a reference EDS is described. The focus is on the traceability of EDS efficiency which is ensured by measurements of the absolute detection efficiency of silicon drift detectors (SDD) and Si(Li) detectors at the laboratory of the PTB using the electron storage ring BESSY II as a primary X-ray source standard. A new test material in development at BAM for testing the performance of an EDS in the energy range below 1 keV is also briefly presented. PMID:25326887

  3. [Energy dispersive x-ray fluorescence spectrometry--a forensic chemistry method for detection of bullet metal residue in gunshot wounds].

    PubMed

    Havel, J; Zelenka, K

    2003-04-01

    The article describes using of energo-dispersive X-ray fluorescence spectrometry (EDXRF) as the forensic method as the tool for detection of metals (gunshot residues--GSR) in connection with gunshot-wounds of persons. PMID:12874887

  4. Energy dispersive x-ray diffractometry as a tool alternative to differential scanning calorimetry for investigating polymer phase transitions

    NASA Astrophysics Data System (ADS)

    Rossi-Albertini, V.; Isopo, A.; Caminiti, R.; Tentolini, U.

    2002-02-01

    Recently, a technique based on energy dispersive x-ray diffraction has been proposed to follow the polymer phase transitions. However, the potentialities of this method were not clear, as well as the experimental conditions in which it is more convenient than differential scanning calorimetry, generally used for the same purpose. In the present letter, the answer to this question is provided. It is shown that the two methods are complementary, rather than equivalent, the heating rate being the relevant parameter to establish which is preferable. The demonstration of this statement is given through the observation of the complex thermal properties of a reference sample studied in both ways at progressively lower heating rates. The connection between such unusual application of x-ray diffraction and the differential scanning calorimetry is discussed in terms of the two possible definitions of entropy.

  5. Low energy X-ray spectra measured with a mercuric iodide energy dispersive spectrometer in a scanning electron microscope

    NASA Technical Reports Server (NTRS)

    Iwanczyk, J. S.; Dabrowski, A. J.; Huth, G. C.; Bradley, J. G.; Conley, J. M.

    1986-01-01

    A mercuric iodide energy dispersive X-ray spectrometer, with Peltier cooling provided for the detector and input field effect transistor, has been developed and tested in a scanning electron microscope. X-ray spectra were obtained with the 15 keV electron beam. An energy resolution of 225 eV (FWHM) for Mn-K(alpha) at 5.9 keV and 195 eV (FWHM) for the Mg-K line at 1.25 keV has been measured. Overall system noise level was 175 eV (FWHM). The detector system characterization with a carbon target demonstrated good energy sensitivity at low energies and lack of significant spectral artifacts at higher energies.

  6. Low energy X-ray spectra measured with a mercuric iodide energy dispersive spectrometer in a scanning electron microscope

    SciTech Connect

    Iwanczyk, J.S.; Dabrowski, A.J.; Huth, G.C.; Bradley, J.G.; Conlay, J.M.; Albee, A.L.

    1986-02-01

    A mercuric iodide energy dispersive x-ray spectrometer, with Peltier cooling provided for the detector and input field effect transistor, has been developed and tested in a scanning electron microscope. X-ray spectra were obtained with the 15 keV electron beam. An energy resolution of 225 eV (FWHM) for Mn-K..cap alpha.. at 5.9 keV and 195 eV (FWHM) for Mg-K line at 1.25 keV has been measured. Overall system noise level was 175 eV (FWHM). The detector system characterization with a carbon target demonstrated good energy sensitivity at low energies and lack of significant spectral artifacts at higher energies.

  7. Low energy x-ray spectra measured with a mercuric iodide energy dispersive spectrometer in a scanning electron microscope

    SciTech Connect

    Iwanczyk, J.S.; Dabrowski, A.J.; Huth, G.C.; Bradley, J.G.; Conley, J.M.; Albee, A.L.

    1985-01-01

    A mercuric iodide energy dispersive x-ray spectrometer, with Peltier cooling provided for the detector and input field effect transistor, has been developed and tested in a scanning electron microscope. X-ray spectra were obtained with the 15 keV electron beam. An energy resolution of 225 eV (FWHM) for Mn-K/sub ..cap alpha../ at 5.9 keV and 195 eV (FWHM) for Mg-K line at 1.25 keV has been measured. Overall system noise level was 175 eV (FWHM). The detector system characterization with a carbon target demonstrated good energy sensitivity at low energies and lack of significant spectral artifacts at higher energies. 16 refs., 5 figs.

  8. X-Ray Study of Noble Metals Dispersed in Borax and B2O3Glasses

    Microsoft Academic Search

    Subodh Kumar Majumdar; Bhupati Kumar Banerjee

    1946-01-01

    IN a previous communication1, it was shown by us that alkali halides such as lithium, sodium, potassium, rubidium and cæsium chloride dissolved in fused boric oxide giving a homogeneous glass. X-ray examination of these glasses reveals sharp diffraction lines due to the dissolved alkali halides together with a few foreign lines which cannot be identified with any known borates of

  9. Rapid spectral and flux time variations in a solar burst observed at various dm-mm wavelengths and at hard X-rays

    NASA Technical Reports Server (NTRS)

    Zodivaz, A. M.; Kaufmann, P.; Correia, E.; Costa, J. E. R.; Takakura, T.; Cliver, E. W.; Tapping, K. F.

    1986-01-01

    A solar burst was observed with high sensitivity and time resolution at cm-mm wavelengths by two different radio observatories (Itapetinga and Algonquin), with high spectral time resolution at dm-mm wavelengths by patrol instruments (Sagamore Hill), and at hard X-rays (HXM Hinotori). At the onset of the major burst time structure there was a rapid rise in the spectral turnover frequency (from 5 to 15 GHz), in about 10s, coincident to a reduction of the spectral index in the optically thin part of the spectrum. The burst maxima were not time coincident at the optically thin radio frequencies and at the different hard X-ray energy ranges. The profiles at higher radio frequencies exhibited better time coincidence to the high energy X-rays. The hardest X-ray spectrum (-3) coincided with peak radio emission at the higher frequency (44 GHz). The event appeared to be built up by a first major injection of softer particles followed by other injections of harder particles. Ultrafast time structures were identified as superimposed on the burst emission at the cm-mm high sensitivity data at X-rays, with predominant repetition rates ranging from 2.0 to 3.5 Hz.

  10. 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.

  11. Effect of electrical charging on scanning electron microscopy-energy dispersive X-ray spectroscopy analysis of insulating materials

    NASA Astrophysics Data System (ADS)

    Imashuku, Susumu; Sakatoku, Shota; Kawai, Jun

    2013-08-01

    We investigated the conditions under which we can obtain reasonable qualitative results in scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) analysis of trace elements in insulating materials using a diluted ionic liquid (EMI-CH3COO) and changing probe current. Below 100 nA, electrical charging of insulating materials was prevented. The probe current of 10 nA was suitable for qualitative analysis because the intensities of peaks from these materials were strong enough to detect trace elements at the concentration of 0.1 wt.% in the sample without interference by sum peaks. Diluted EMI-CH3COO can also be used for SEM-EDX quantitative analysis of insulating materials as discharging agents. In contrast, when insulating materials were electrically charged, the obtained spectra contained characteristic X-rays of the insulating materials with low energies and of materials other than the samples such as the sample stage and the collimator in the X-ray detector. This is because electrons from the electron beam were decelerated by and deflected from the insulating materials. By coating the insulating materials with the diluted EMI-CH3COO, the deceleration and deflection of the electron beam were prevented.

  12. In situ, energy-dispersive X-ray diffraction study of natural gas conversion by CO[sub 2] reforming

    Microsoft Academic Search

    A. T. Ashcroft; A. K. Cheetham; R. H. Jones; S. Natarajan; J. M. Thomas; D. Waller; S. M. Clark

    1993-01-01

    The selective CO[sub 2] reforming of methane to synthesis gas over a rare-earth iridate pyrochlore, Ln[sub 2]Ir[sub 2]O[sub 7] (Ln = Eu), and rare-earth ruthenate pyrochlores, Ln[sub 2]Ru[sub 2]O[sub 7] (Ln = Nd, Sm, Eu, Gd), has been studied in situ by using energy-dispersive X-ray diffraction with synchrotron radiation. Analysis of the diffraction data shows that the oxides are activated

  13. In situ multi-element analyses by energy-dispersive X-ray fluorescence on varnishes of historical violins

    NASA Astrophysics Data System (ADS)

    Echard, Jean-Philippe

    2004-10-01

    Varnishes of Italian violins and other historical stringed instruments have been analyzed by energy-dispersive X-ray fluorescence (EDXRF). The instruments whose varnishes were to be analyzed were chosen from the collection kept in Musée de la Musique in Paris. Direct analyses were performed on instrument varnishes, without any sampling and non-destructively, showing inorganic elements such as lead, mercury and iron that could be related to siccatives or pigments. Analytical results and their comparison with old formulae or traditional recipes of violin varnishes, as with the few previous analytical results, will be discussed.

  14. Multi-wavelength coverage of state transitions in the new black hole X-ray binary swift J1910.2-0546

    SciTech Connect

    Degenaar, N.; Maitra, D.; Reynolds, M. T.; Miller, J. M.; Reis, R. C.; King, A. L.; Gültekin, K. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Cackett, E. M. [Department of Physics and Astronomy, Wayne State University, 666 West Hancock Street, Detroit, MI 48201 (United States); Bailyn, C. D.; Buxton, M. M.; MacDonald, R. K. D. [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Fabian, A. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 OHA (United Kingdom); Fox, D. B. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Rykoff, E. S., E-mail: degenaar@umich.edu [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)

    2014-04-01

    Understanding how black holes accrete and supply feedback to their environment is one of the outstanding challenges of modern astrophysics. Swift J1910.2-0546 is a candidate black hole low-mass X-ray binary that was discovered in 2012 when it entered an accretion outburst. To investigate the binary configuration and the accretion morphology, we monitored the evolution of the outburst for ?3 months at X-ray, UV, optical (B, V, R, I), and near-infrared (J, H, K) wavelengths using Swift and SMARTS. The source evolved from a hard to a soft X-ray spectral state with a relatively cold accretion disk that peaked at ?0.5 keV. A Chandra/HETG spectrum obtained during this soft state did not reveal signatures of an ionized disk wind. Both the low disk temperature and the absence of a detectable wind could indicate that the system is viewed at relatively low inclination. The multi-wavelength light curves revealed two notable features that appear to be related to X-ray state changes. First, a prominent flux decrease was observed in all wavebands ? 1-2 weeks before the source entered the soft state. This dip occurred in (0.6-10 keV) X-rays ? 6 days later than at longer wavelengths, which could possibly reflect the viscous timescale of the disk. Second, about two weeks after the source transitioned back into the hard state, the UV emission significantly increased while the X-rays steadily decayed. We discuss how these observations may reflect changes in the accretion morphology, perhaps related to the quenching/launch of a jet or the collapse/recovery of a hot flow.

  15. Methodology toward 3D micro X-ray fluorescence imaging using an energy dispersive charge-coupled device detector.

    PubMed

    Garrevoet, Jan; Vekemans, Bart; Tack, Pieter; De Samber, Björn; Schmitz, Sylvia; Brenker, Frank E; Falkenberg, Gerald; Vincze, Laszlo

    2014-12-01

    A new three-dimensional (3D) micro X-ray fluorescence (?XRF) methodology based on a novel 2D energy dispersive CCD detector has been developed and evaluated at the P06 beamline of the Petra-III storage ring (DESY) in Hamburg, Germany. This method is based on the illumination of the investigated sample cross-section by a horizontally focused beam (vertical sheet beam) while fluorescent X-rays are detected perpendicularly to the sheet beam by a 2D energy dispersive (ED) CCD detector allowing the collection of 2D cross-sectional elemental images of a certain depth within the sample, limited only by signal self-absorption effects. 3D elemental information is obtained by a linear scan of the sample in the horizontal direction across the vertically oriented sheet beam and combining the detected cross-sectional images into a 3D elemental distribution data set. Results of the 3D ?XRF analysis of mineral inclusions in natural deep Earth diamonds are presented to illustrate this new methodology. PMID:25346101

  16. An Optical Interferometer with Wavelength Dispersion

    E-print Network

    T. R. Bedding; J. G. Robertson; R. G. Marson

    1994-04-04

    MAPPIT is an optical interferometer installed at the coude focus of the 3.9-m Anglo-Australian Telescope. The instrument combines non-redundant masking with wavelength dispersion and is able to record fringes simultaneously over a wide bandwidth. For typical observations centred near 600 nm, the bandwidth is 55 nm and the spectral resolution is 3 nm. This paper describes the instrument and the data processing methods and presents some results. We find the star sigma Sgr to be a close binary; the system is only partially resolved, with a separation of (11.5 +/- 2) milliarcsec (assuming the components to have equal magnitudes). We also give angular diameter measurements of two red giant stars, alpha Sco and beta Gru. The observations of beta Gru (spectral type M5 III) resolve the star for the first time and give an equivalent uniform-disk diameter of (27 +/- 3) milliarcsec.

  17. Evidence for core–shell nanoclusters in oxygen dispersion strengthened steels measured using X-ray absorption spectroscopy

    SciTech Connect

    Liu, S.; Odette, G. R.; Segre, C. U. [UCSB

    2014-02-01

    Nanostructured ferritic alloys (NFA) dispersion strengthened by an ultra high density of Y–Ti–O enriched nano-features (NF) exhibit superior creep strength and the potential for high resistance to radiation damage. However, the detailed character of the NF, that precipitate from solid solution during hot consolidation of metallic powders mechanically alloyed with Y?O?, are not well understood. In order to clarify the nature of the NF, X-ray absorption spectroscopy (XAS) technique, including X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) were used to characterize the local structure of the Ti and Y atoms in both NFA powders and consolidated alloys. The powders were characterized in the as-received, as-milled and after annealing milled powders at 850, 1000 and 1150 °C. The consolidated alloys included powders hot isostatic pressed (HIPed) at 1150 °C and commercial vendor alloys, MA957 and J12YWT. The NFA XAS data were compared various Ti and Y-oxide standards. The XANES and EXAFS spectra for the annealed and HIPed powders are similar and show high temperature heat treatments shift the Y and Ti to more oxidized states that are consistent with combinations of Y?Ti?O? and, especially, TiO. However, the MA957 and J12YWT and annealed–consolidated powder data differ. The commercial vendor alloys results more closely resemble the as-milled powder data and all show that a significant fraction of substitutional Ti remains dissolved in the (BCC) ferrite matrix.

  18. Energy-dispersive X-ray diffraction using an annular beam.

    PubMed

    Dicken, A J; Evans, J P O; Rogers, K D; Greenwood, C; Godber, S X; Prokopiou, D; Stone, N; Clement, J G; Lyburn, I; Martin, R M; Zioupos, P

    2015-05-18

    We demonstrate material phase identification by measuring polychromatic diffraction spots from samples at least 20 mm in diameter and up to 10 mm thick with an energy resolving point detector. Within our method an annular X-ray beam in the form of a conical shell is incident with its symmetry axis normal to an extended polycrystalline sample. The detector is configured to receive diffracted flux transmitted through the sample and is positioned on the symmetry axis of the annular beam. We present the experiment data from a range of different materials and demonstrate the acquisition of useful data with sub-second collection times of 0.5 s; equating to 0.15 mAs. Our technique should be highly relevant in fields that demand rapid analytical methods such as medicine, security screening and non-destructive testing. PMID:26074592

  19. Interest of energy dispersive X-ray microanalysis to characterize the surface composition of milk powder particles.

    PubMed

    Murrieta-Pazos, I; Galet, L; Rolland, C; Scher, J; Gaiani, C

    2013-11-01

    Energy dispersive X-ray (EDX) is a technique rarely used for organic powders. Nevertheless, this technique is of great interest in the characterization of milk particle surface. In order to validate the method, the EDX technique was tested on pure milk components, on model powders composed of different ratio of lactose/whey proteins and on whole milk powders presenting or not free fat at the surface. For all these powders, satisfactory results were obtained with correct experimental atomic percentages in comparison with expected theoretical percentages. The technique was then applied to skimmed and whole milk powders sieved in 4 fractions. The surface and the core (cut particle) were analyzed by EDX and compared. A relationship between the particle size and the surface composition was observed. X-ray photoelectron spectroscopy (XPS) often used to characterize milk powder surface, however no differences were observed between surface and core composition using this method. The depth of analysis by EDX is far more significant (1 ?m) in comparison to that of the XPS (5 nm); hence it was concluded that the analysis of cut particle by EDX was not interesting since too close to the results obtained at the surface. Finally, the technique was coupled with XPS and successful hypothesis concerning composition gradients were done. PMID:23831670

  20. Photometric study of single-shot energy-dispersive x-ray diffraction at a laser plasma facility

    SciTech Connect

    Hoidn, O. R.; Seidler, G. T., E-mail: seidler@uw.edu [Physics Department, University of Washington, Seattle, Washington 98195-1560 (United States)

    2014-01-15

    The low repetition rates and possible shot-to-shot variations in laser-plasma studies place a high value on single-shot diagnostics. For example, white-beam scattering methods based on broadband backlighter x-ray sources are used to determine changes in the structure of laser-shocked crystalline materials by the evolution of coincidences of reciprocal lattice vectors and kinematically allowed momentum transfers. Here, we demonstrate that white-beam techniques can be extended to strongly disordered dense plasma and warm dense matter systems where reciprocal space is only weakly structured and spectroscopic detection is consequently needed to determine the static structure factor and thus, the ion-ion radial distribution function. Specifically, we report a photometric study of energy-dispersive x-ray diffraction (ED-XRD) for structural measurement of high energy density systems at large-scale laser facilities such as OMEGA and the National Ignition Facility. We find that structural information can be obtained in single-shot ED-XRD experiments using established backlighter and spectrometer technologies.

  1. Determination of selenium at trace levels in geologic materials by energy-dispersive X-ray fluorescence spectrometry

    USGS Publications Warehouse

    Wahlberg, J.S.

    1981-01-01

    Low levels of selenium (0.1-500 ppm) in both organic and inorganic geologic materials can be semiquantitatively measured by isolating Se as a thin film for presentation to an energy-dispersive X-ray fluorescence spectrometer. Suitably pulverized samples are first digested by fusing with a mixture of Na2CO3 and Na2O2. The fusion cake is dissolved in distilled water, buffered with NH4Cl, and filtered to remove Si and the R2O3 group. A carrier solution of Na2TeO4, plus solid KI, hydrazine sulfate and Na2SO3, is added to the filtrate. The solution is then vacuum-filtered through a 0.45-??m pore-size filter disc. The filter, with the thin film of precipitate, is supported between two sheets of Mylar?? film for analysis. Good agreement is shown between data reported in this study and literature values reported by epithermal neutron-activation analysis and spectrofluorimetry. The method can be made quantitative by utilizing a secondary precipitation to assure complete recovery of the Se. The X-ray method offers fast turn-around time and a reasonably high production rate. ?? 1981.

  2. Evaluation of imaging properties of soft x-ray multilayer mirrors and their application to highly dispersive spectral imaging

    SciTech Connect

    Kolachevsky, N. N.; Mitropolsky, M. M.; Ragozin, E. N.; Salashchenko, N. N.; Slemzin, V. A.; Zhitnik, I. A. [Optics Division of the P. N. Lebedev Physics Inst., 53 Leninsky ave., 117924 Moscow (Russian Federation); Institute for Physics of Microstructures, 46 Uljanov Str., 603600 Nizhny Novgorod (Russian Federation); Optics Division of the P. N. Lebedev Physics Inst., 53 Leninsky ave., 117924 Moscow (Russian Federation)

    1995-05-01

    A variety of normal-incidence multilayer mirrors (MMs) intended for studies of astrophysical and laboratory soft-x-ray radiation sources have been synthesized on concave (r=1.6-2.0 m) fused silica substrates. The MMs range in resonance wavelength {lambda}0 from 4.5 to 31 nm. Their imaging capability has been evaluated from small-source imaging tests employing to a laser-plasma broadband XUV radiation source and a high-resolution XUV photographic film. The photographs testify to a subarcsecond angular resolution. For 17.5-nm MMs, a resolution of at least {approx_equal}0.32 arcseconds has been demonstrated, which is only 2.4{lambda}0/D for the MMs involved.

  3. X-ray diffraction study of the dependence of the fine TiC structure on dispersion of hardening phase particles

    SciTech Connect

    Ilyasov, V.V.; Zaitsev, S.M.; Kozakov, A.T.; Pityulin, A.N. [Don State Technical Univ., Rostov-on-Don (Russian Federation). Dept. of Physics] [Don State Technical Univ., Rostov-on-Don (Russian Federation). Dept. of Physics

    1995-05-01

    The special features of the fine structure of the TiC-based composite were studied by the methods of X-ray diffraction, the methods of local X-ray spectrum analysis and optical microscopy. The correlation between the thin TiC structure parameter values and dispersion of TiN phase particles was established. The particular aim of this work was to study the fine structure (dimensionals of coherent scattering regions (CSP), microdeformation) of the multicomponent alloy with a complex Ni-Mo binder (doped with Al, V, Co, Nb) caused by the dispersion of Ti nitride-phase (TiN) particles.

  4. Dendrochemical patterns of calcium, zinc, and potassium related to internal factors detected by energy dispersive X-ray fluorescence (EDXRF)

    USGS Publications Warehouse

    Smith, Kevin T.; Balouet, Jean Christophe; Shortle, Walter C.; Chalot, Michel; Beaujard, François; Grudd, Håkan; Vroblesky, Don A.; Burkem, Joel G.

    2014-01-01

    Energy dispersive X-ray fluorescence (EDXRF) provides highly sensitive and precise spatial resolution of cation content in individual annual growth rings in trees. The sensitivity and precision have prompted successful applications to forensic dendrochemistry and the timing of environmental releases of contaminants. These applications have highlighted the need to distinguish dendrochemical effects of internal processes from environmental contamination. Calcium, potassium, and zinc are three marker cations that illustrate the influence of these processes. We found changes in cation chemistry in tree rings potentially due to biomineralization, development of cracks or checks, heartwood/sapwood differentiation, intra-annual processes, and compartmentalization of infection. Distinguishing internal from external processes that affect dendrochemistry will enhance the value of EDXRF for both physiological and forensic investigations.

  5. In situ, energy-dispersive X-ray diffraction study of natural gas conversion by CO[sub 2] reforming

    SciTech Connect

    Ashcroft, A.T. (Univ. of Oxford (United Kingdom)); Cheetham, A.K. (Univ. of California, Santa Barbara (United States)); Jones, R.H.; Natarajan, S.; Thomas, J.M.; Waller, D. (Royal Institution of Great Britain, London (United Kingdom)); Clark, S.M. (Daresbury Lab. (United Kingdom))

    1993-04-01

    The selective CO[sub 2] reforming of methane to synthesis gas over a rare-earth iridate pyrochlore, Ln[sub 2]Ir[sub 2]O[sub 7] (Ln = Eu), and rare-earth ruthenate pyrochlores, Ln[sub 2]Ru[sub 2]O[sub 7] (Ln = Nd, Sm, Eu, Gd), has been studied in situ by using energy-dispersive X-ray diffraction with synchrotron radiation. Analysis of the diffraction data shows that the oxides are activated by reduction to the platinum group metal, the iridate by a second-order kinetic reaction, and the ruthenates by a first-order process. Temperature programmed reductions under carbon monoxide, hydrogen, and methane establish that the iridates proceed directly to the metal, whereas the ruthenates reduce via an oxygen deficient pyrochlore. 18 refs., 7 figs., 1 tab.

  6. Energy dispersive X-ray fluorescence analysis of mine waters from the Migori Gold Mining Belt in Southern Nyanza, Kenya.

    PubMed

    Odumo, O B; Mustapha, A O; Patel, J P; Angeyo, H K

    2011-09-01

    Analyses of water samples from Mikei, Osiri, Masara and Macalder (Makalda) gold mines of the Migori gold mining belt of Southwestern Kenya were done to determine the level of heavy metals using the Energy Dispersive X-ray Fluorescence technique. The concentrations of the heavy metals were; copper (29.34 ± 5.01-14,975.59 ± 616.14 ?g/L); zinc (33.69 ± 4.29-683.15 ± 32.93 ?g/L); arsenic (958.16 ± 60.14-18,047.52 ± 175.00 ?g/L) and lead (19.51 ± 5.5-214.53 ± 6.29 ?g/L). High levels of arsenic and lead were noted. These heavy metals are not only dangerous to the lives of miners and the local inhabitants; they are also a threat to aquatic life since these waters finally find their way into Lake Victoria. PMID:21681402

  7. Study of the Interaction of ZDDP and Dispersants Using X-ray Absorption Near Edge Structure Spectroscopy—Part 2: Tribochemical Reactions

    Microsoft Academic Search

    E. S. Yamaguchi; Z. Zhang; M. Kasrai; G. M. Bancroft

    2003-01-01

    The antiwear properties of zinc dialkyldithiophosphate (ZDDP), dispersants, and mixtures of ZDDP and different dispersants have been evaluated using a pin-on-flat Plint wear machine. Tribochemical interactions between ZDDP and dispersants have been investigated under boundary lubrication conditions by means of X-ray absorption near edge structure (XANES) spectroscopy, probing the phosphorus, sulfur and nitrogen absorption edges. The results show that the

  8. X-ray beamsplitter

    DOEpatents

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

    1987-08-07

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

  9. X-ray beamsplitter

    DOEpatents

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

    1989-01-01

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

  10. Chandra Multi-wavelength Project (ChaMP). II. First Results of X-ray Source Properties

    E-print Network

    D. -W. Kim; B. J. Wilkes; P. J. Green; R. A. Cameron; J. J. Drake; N. R. Evans; P. Freeman; T. J. Gaetz; H. Ghosh; F. R. Harnden, Jr.; M. Karovska; V. Kashyap; P. W. Maksym; P. W. Ratzlaff; E. M. Schlegel; J. D. Silverman; H. D. Tananbaum; A. A. Vikhlinin

    2003-08-27

    We present the first results of ChaMP X-ray source properties obtained from the initial sample of 62 observations. The data have been uniformly reduced and analyzed with techniques specifically developed for the ChaMP and then validated by visual examination. Utilizing only near on-axis, bright X-ray sources (to avoid problems caused by incompleteness and the Eddington bias), we derive the Log(N)-Log(S) relation in soft (0.5-2 keV) and hard (2-8 keV) energy bands. The ChaMP data are consistent with previous results of ROSAT, ASCA and Chandra deep surveys. In particular, our data nicely fill in the flux gap in the hard band between the Chandra Deep Field data and the previous ASCA data. We check whether there is any systematic difference in the source density between cluster and non-cluster fields and also search for field-to-field variations, both of which have been previously reported. We found no significant field-to-field cosmic variation in either test within the statistics (~1 sigma) across the flux levels included in our sample. In the X-ray color-color plot, most sources fall in the location characterized by photon index = 1.5-2 and NH = a few x 10^20 cm^2, suggesting that they are typical broad-line AGNs. There also exist a considerable number of sources with peculiar X-ray colors (e.g., highly absorbed, very hard, very soft). We confirm a trend that on average the X-ray color hardens as the count rate decreases. Since the hardening is confined to the softest energy band (0.3-0.9 keV), we conclude it is most likely due to absorption. We cross-correlate the X-ray sources with other catalogs and describe their properties in terms of optical color, X-ray-to-optical luminosity ratio and X-ray colors.

  11. The Chandra Multi-Wavelength Project (ChaMP): A Serendipitous X-Ray Survey Using Chandra Archival Data

    NASA Technical Reports Server (NTRS)

    Wilkes, Belinda; Lavoie, Anthony R. (Technical Monitor)

    2000-01-01

    The launch of the Chandra X-ray Observatory in July 2000 opened a new era in X-ray astronomy. Its unprecedented, < 1" spatial resolution and low background is providing views of the X-ray sky 10-100 times fainter than previously possible. We have begun to carry out a serendipitous survey of the X-ray sky using Chandra archival data to flux limits covering the range between those reached by current satellites and those of the small area Chandra deep surveys. We estimate the survey will cover about 8 sq.deg. per year to X-ray fluxes (2-10 keV) in the range 10(exp -13) - 6(exp -16) erg cm2/s and include about 3000 sources per year, roughly two thirds of which are expected to be active galactic nuclei (AGN). Optical imaging of the ChaMP fields is underway at NOAO and SAO telescopes using g',r',z' colors with which we will be able to classify the X-ray sources into object types and, in some cases, estimate their redshifts. We are also planning to obtain optical spectroscopy of a well-defined subset to allow confirmation of classification and redshift determination. All X-ray and optical results and supporting optical data will be place in the ChaMP archive within a year of the completion of our data analysis. Over the five years of Chandra operations, ChaMP will provide both a major resource for Chandra observers and a key research tool for the study of the cosmic X-ray background and the individual source populations which comprise it. ChaMP promises profoundly new science return on a number of key questions at the current frontier of many areas of astronomy including solving the spectral paradox by resolving the CXRB, locating and studying high redshift clusters and so constraining cosmological parameters, defining the true, possibly absorbed, population of quasars and studying coronal emission from late-type stars as their cores become fully convective. The current status and initial results from the ChaMP will be presented.

  12. Component analyses of urinary nanocrystallites of uric acid stone formers by combination of high-resolution transmission electron microscopy, fast Fourier transformation, energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared spectroscopy.

    PubMed

    Sun, Xin-Yuan; Xue, Jun-Fa; Xia, Zhi-Yue; Ouyang, Jian-Ming

    2015-06-01

    This study aimed to analyse the components of nanocrystallites in urines of patients with uric acid (UA) stones. X-ray diffraction (XRD), Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy (HRTEM), fast Fourier transformation (FFT) of HRTEM, and energy dispersive X-ray spectroscopy (EDS) were performed to analyse the components of these nanocrystallites. XRD and FFT showed that the main component of urinary nanocrystallites was UA, which contains a small amount of calcium oxalate monohydrate and phosphates. EDS showed the characteristic absorption peaks of C, O, Ca and P. The formation of UA stones was closely related to a large number of UA nanocrystallites in urine. A combination of HRTEM, FFT, EDS and XRD analyses could be performed accurately to analyse the components of urinary nanocrystallites. PMID:26023155

  13. An X-ray absorption spectroscopy study of an oxide dispersion strengthened steel

    Microsoft Academic Search

    M. A. Pouchon; A. J. Kropf; A. Froideval; C. Degueldre; W. Hoffelner

    2007-01-01

    Oxide dispersion strengthened (ODS) steels are being investigated as possible structural material for components of future nuclear power plants. The dispersoids in the matrix (yttria particles) serve as pinning points for moving dislocations, and thereby improve the creep behavior of the material. Depending on the product, the dimension of the particles is in the range from a few nm up

  14. Chandra Multi-wavelength Project (ChaMP). II. First Results of X-ray Source Properties

    E-print Network

    Kim, Dong-Woo

    for the ChaMP and then validated by visual examination. Utilizing only near on-axis, bright X-ray sources (to avoid problems caused by incompleteness and the Eddington bias), we derive the Log(N)- Log(S) relation systematic difference in the source density between cluster and non-cluster fields and also search for field

  15. The beneficial use of composite samples in the energy-dispersive X-ray analysis of highly radioactive Nimonic PE16

    Microsoft Academic Search

    P. K. Rose; J. Rowe

    1987-01-01

    A new technique for preparing 3 mm diameter disc samples for TEM is presented. It permits quantitative energy- dispersive X-ray (EDX) analysis of radioactive materials where otherwise high sample activity causes saturation of the EDX detector. The new composite sample geometry, comprising a small disc of radioactive material within an annulus of compatible unirradiated material, has up to ~ 50

  16. Effect of x-ray energy dispersion in digital subtraction imaging at the iodine K-edge--A Monte Carlo study

    E-print Network

    Ramello, Luciano

    Effect of x-ray energy dispersion in digital subtraction imaging at the iodine K-edge--A Monte at the iodine K-edge, suitable for angiographic imaging application, is investigated. The average energies of the two beams bracketing the iodine K-edge are set to the values of 31.2 and 35.6 keV corresponding

  17. Application of soft X-ray absorption spectroscopy in chemical characterization of antiwear films generated by ZDDP Part II: the effect of detergents and dispersants

    Microsoft Academic Search

    Zhanfeng Yin; M. Kasrai; G. M. Bancroft; K. Fyfe; M. L. Colaianni; K. H. Tan

    1997-01-01

    X-ray absorption near edge structure (XANES) spectroscopy has been used to study the chemical nature of the antiwear films generated on steel surfaces using zinc dialkyldithiophosphates (ZDDPs), in the presence of detergents and dispersants. The spectra were recorded both in total electron yield (TEY) and fluorescence yield (FY) modes, to investigate the chemical nature of P,S, Ca and O on

  18. Evaluation of the acetate buffer attack of a sequential extraction scheme for marine particulate metal speciation studies by scanning electron microscopy with energy dispersive X-ray analysis

    Microsoft Academic Search

    F Baffi; C Ianni; M Ravera; F Soggia; E Magi

    1998-01-01

    Scanning electron microscopy, with energy dispersive X-ray analysis (SEM-EDX), has been used to evaluate and possibly optimize, the first step (acetate buffer attack for exchangeable and carbonatic fractions) of a sequential selective extraction scheme. The extraction has been performed on two different particulates, a certified reference plankton and a real marine suspended particulate, using an increased acetate concentration and various

  19. The Wavelength-Dispersive Spectrometer and Its Proposed Use in the Analytical Electron Microscope

    NASA Technical Reports Server (NTRS)

    Goldstein, Joseph I.; Lyman, Charles E.; Williams, David B.

    1989-01-01

    The Analytical Electron Microscope (AEM) equipped with a wavelength-dispersive spectrometer (WDS) should have the ability to resolve peaks which normally overlap in the spectra from an energy-dispersive spectrometer (EDS). With a WDS it should also be possible to measure lower concentrations of elements in thin foils due to the increased peak-to-background ratio compared with EDS. The WDS will measure X-ray from the light elements (4 less than Z less than 1O) more effectively. This paper addresses the possibility of interfacing a compact WDS with a focussing circle of approximately 4 cm to a modem AEM with a high-brightness (field emission) source of electrons.

  20. Penning source for calibration of x-ray and EUV optics and spectrometers at wavelengths as short as 50 A

    Microsoft Academic Search

    Edwin M. Kellogg; Bradford J. Wargelin; Timothy J. Norton; Roger Eng; Jeffery J. Kolodziejczak

    1995-01-01

    We report on the development and evaluation of a redesigned version of the Penning gas discharge source of x-ray and EUV radiation previously described by Finley et al. The most significant new features are the use of stronger permanent magnets and spill-proof quick- disconnect water cooling line fittings. Using aluminum cathodes and Ar discharge gas, and with a 0.5 mm

  1. Discovery And Multi-wavelength Observations Of The New X-ray Transient Source Swift J1357.2-0933

    Microsoft Academic Search

    Hans A. Krimm; J. Bloom; N. Gehrels; S. T. Holland; J. A. Kennea; C. B. Markwardt; J. Miller-Jones; G. Sivakoff

    2011-01-01

    We report on the discovery by the Swift Gamma-Ray Burst Explorer of the transient source Swift J1357.2-0933 and the subsequent course of an outburst beginning in January 2011. The source is most likely a low-mass X-ray binary, although it is not yet clear whether the compact object is a black hole or neutron star. The object is off the galactic

  2. Optimizing the performance of nickel-like collisionally pumped x-ray lasers. II. Lasers for the wavelength range 50-100Å

    NASA Astrophysics Data System (ADS)

    Pert, G. J.

    2007-02-01

    Soft x-ray lasers operating in the super- 100Å regime and using grazing incidence pumping methods are now established as efficient sources of radiation in this waveband. The concepts underlying this approach are to separate the ionization and excitation phases of the laser, and to match the pumping density of the latter to the optimal for gain generation. It is therefore of considerable interest to examine whether these ideas can be successfully applied to sub- 100Å lasers. Three problems arise: first the adverse scaling of ionization with temperature for high atomic number ions, second the strong thermal conduction at these temperatures leads to a large hot zone upstream of the absorption, and third the optimum pumping density is greater than the critical density of 1?m wavelength, solid state pump lasers. Using analytic models and simulation we identify a strategy to overcome these problems using a pre-pulse of a mixed harmonic and fundamental radiation of Nd-glass laser radiation followed by the main pumping pulse of the fundamental normally incident. Due to the large upstream thermal zone and the high ionization temperature, we find that the energy required in the pre-pulse is much ( ˜3 times) larger than that in the main, and that the energy needed consequently scales rapidly with the atomic number and therefore decreasing x-ray wavelength. Systems generating output energies of a few tens of ?J are examined at wavelengths between 50 and 70Å .

  3. Mapping the Ionization State of Laser-Irradiated Ar Gas Jets With Multi-Wavelength Monochromatic X-Ray Imaging

    SciTech Connect

    Kugland, N L; Doppner, T; Kemp, A; Schaeffer, D; Glenzer, S H; Niemann, C

    2010-04-08

    Two-dimensional monochromatic images of fast-electron stimulated Ar K{alpha} and He-{alpha} x-ray self-emission have recorded a time-integrated map of the extent of Ar{sup {approx}6+} and Ar{sup 16+} ions, respectively, within a high density (10{sup 20} cm{sup -3} atomic density) Ar plasma. This plasma was produced by irradiating a 2 mm wide clustering Ar gas jet with an ultra-high intensity (10{sup 19} W/cm{sup 2}, 200 fs) Ti:Sapphire laser operating at 800 nm. Spherically bent quartz crystals in the 200 (for K{alpha}) and 201 (for He-{alpha}) planes were used as near-normal incidence reflective x-ray optics. We see that a large (830 {micro}m long) region of plasma emits K{alpha} primarily along the laser axis, while the He-{alpha} emission is confined to smaller hot spot (230 {micro}m long) region that likely corresponds to the focal volume of the f/8 laser beam. X-ray spectra from a Bragg spectrometer operating in the von Hamos geometry, which images in one dimension, indicate that the centroids of the K{alpha} and He-{alpha} emission regions are separated by approximately 330 {micro}m along the laser axis.

  4. Introduction to X-ray microanalysis in biology.

    PubMed

    Roomans, G M

    1988-05-01

    This paper gives an introduction to X-ray microanalysis for biologists. The physical principles of X-ray microanalysis and the instrumentation used in wavelength-dispersive and energy-dispersive analysis are reviewed. A special problem in biological microanalysis is the adequate preparation of the specimen: The preparative method must retain the localization of the element(s) of interest and allow identification of morphological features at the level of analytical resolution. Conventional preparation methods for electron microscopy have only a limited applicability in biological X-ray microanalysis, and often cryomethods have to be used. Methods for qualitative analysis and some common pitfalls and artefacts are discussed. The possibilities and limitations of electron-probe X-ray microanalysis with regard to biological specimens are compared to those of other microanalytical techniques. PMID:3199228

  5. Atomic-scale chemical imaging and quantification of metallic alloy structures by energy-dispersive X-ray spectroscopy.

    PubMed

    Lu, Ping; Zhou, Lin; Kramer, M J; Smith, David J

    2014-01-01

    Determination of atomic-scale crystal structure for nanostructured intermetallic alloys, such as magnetic alloys containing Al, Ni, Co (alnico) and Fe, is crucial for understanding physical properties such as magnetism, but technically challenging due to the small interatomic distances and the similar atomic numbers. By applying energy-dispersive X-ray spectroscopy (EDS) mapping to the study of two intermetallic phases of an alnico alloy resulting from spinodal decomposition, we have determined atomic-scale chemical composition at individual lattice sites for the two phases: one is the B2 phase with Fe0.76Co0.24 -Fe0.40Co0.60 ordering and the other is the L2(1) phase with Ni0.48Co0.52 at A-sites, Al at B(?)-sites and Fe0.20Ti0.80 at B(??)-sites, respectively. The technique developed through this study represents a powerful real-space approach to investigate structure chemically at the atomic scale for a wide range of materials systems. PMID:24492747

  6. Atomic-scale Chemical Imaging and Quantification of Metallic Alloy Structures by Energy-Dispersive X-ray Spectroscopy

    PubMed Central

    Lu, Ping; Zhou, Lin; Kramer, M. J.; Smith, David J.

    2014-01-01

    Determination of atomic-scale crystal structure for nanostructured intermetallic alloys, such as magnetic alloys containing Al, Ni, Co (alnico) and Fe, is crucial for understanding physical properties such as magnetism, but technically challenging due to the small interatomic distances and the similar atomic numbers. By applying energy-dispersive X-ray spectroscopy (EDS) mapping to the study of two intermetallic phases of an alnico alloy resulting from spinodal decomposition, we have determined atomic-scale chemical composition at individual lattice sites for the two phases: one is the B2 phase with Fe0.76Co0.24 -Fe0.40Co0.60 ordering and the other is the L21 phase with Ni0.48Co0.52 at A-sites, Al at B?-sites and Fe0.20Ti0.80 at B??-sites, respectively. The technique developed through this study represents a powerful real-space approach to investigate structure chemically at the atomic scale for a wide range of materials systems. PMID:24492747

  7. Trace elements determination by energy dispersive X-ray fluorescence (EDXRF) in human placenta and membrane: a comparative study.

    PubMed

    Custódio, P J; Carvalho, M L; Nunes, F

    2003-04-01

    This work is an application of energy dispersive X-ray fluorescence (EDXRF) as an analytical technique for trace elemental determination in human membrane and placenta and elemental concentrations correlations in both tissues. Whole samples were collected during the delivery from healthy mothers and full-term pregnancies. The age of the mother was between 25 and 40 years old, and the weight of the infants ranged from 2.56 to 4.05 kg. Samples were lyophilised and analysed without any chemical treatment. No significant differences in elemental content of placenta and membrane samples were observed except for Ca. Very low levels of Se, As and Pb were observed in all the analysed samples. Zn, considered as one of the key elements in newborn health, was not significantly different in the analysed samples, all of which originated from healthy mothers and healthy babies. The obtained values agree with the literature except for Ca, which is much higher in the studied samples. PMID:12733023

  8. NASA Li/CF(x) cell problem analysis: Scanning electron microscopy with energy dispersive x ray spectrometry

    NASA Technical Reports Server (NTRS)

    Baker, John

    1991-01-01

    An analysis was made of Lithium/carbon fluoride cell parts for possible chloride contamination induced by exposure to thionyl chloride (SOCl2); various samples were submitted for analysis. Only a portion of the analysis which has been conducted is covered, herein, namely analysis by scanning electron microscopy with energy dispersive x ray spectrometry (SEM/EDS). A strip of nickel was exposed to SOCl2 vapors to observe variations in surface concentrations of sulfur and chlorine with time. By detecting chlorine one can not infer contamination by SOCl2 only that contamination is present. Six samples of stainless steel foil were analyzed for chlorine using EDS. Chlorine was not detected on background samples but was detected on the samples which had been handled including those which had been cleaned. Cell covers suspected of being contaminated while in storage and covers which were not exposed to the same storage conditions were analyzed for chlorine. Although no chlorine was found on the covers from cells, it was found on all stored covers. Results are presented with techniques shown for analysis and identification. Relevant photomicrographs are presented.

  9. NASA Li/CF(x) cell problem analysis: Scanning electron microscopy with energy dispersive x ray spectrometry

    NASA Astrophysics Data System (ADS)

    Baker, John

    1991-05-01

    An analysis was made of Lithium/carbon fluoride cell parts for possible chloride contamination induced by exposure to thionyl chloride (SOCl2); various samples were submitted for analysis. Only a portion of the analysis which has been conducted is covered, herein, namely analysis by scanning electron microscopy with energy dispersive x ray spectrometry (SEM/EDS). A strip of nickel was exposed to SOCl2 vapors to observe variations in surface concentrations of sulfur and chlorine with time. By detecting chlorine one can not infer contamination by SOCl2 only that contamination is present. Six samples of stainless steel foil were analyzed for chlorine using EDS. Chlorine was not detected on background samples but was detected on the samples which had been handled including those which had been cleaned. Cell covers suspected of being contaminated while in storage and covers which were not exposed to the same storage conditions were analyzed for chlorine. Although no chlorine was found on the covers from cells, it was found on all stored covers. Results are presented with techniques shown for analysis and identification. Relevant photomicrographs are presented.

  10. Misfit strain of oxygen precipitates in Czochralski silicon studied with energy-dispersive X-ray diffraction

    SciTech Connect

    Gröschel, A., E-mail: alexander.groeschel@fau.de; Will, J.; Bergmann, C.; Magerl, A. [Crystallography and Structural Physics, University of Erlangen-Nürnberg, Staudtstr. 3, 91058 Erlangen (Germany)

    2014-06-21

    Annealed Czochralski Silicon wafers containing SiO{sub x} precipitates have been studied by high energy X-ray diffraction in a defocused Laue setup using a laboratory tungsten tube. The energy dispersive evaluation of the diffracted Bragg intensity of the 220 reflection within the framework of the statistical dynamical theory yields the static Debye-Waller factor E of the crystal, which gives access to the strain induced by the SiO{sub x} precipitates. The results are correlated with precipitate densities and sizes determined from transmission electron microscopy measurements of equivalent wafers. This allows for the determination of the constrained linear misfit ? between precipitate and crystal lattice. For samples with octahedral precipitates the values ranging from ??=?0.39 (+0.28/?0.12) to ??=?0.48 (+0.34/?0.16) indicate that self-interstitials emitted into the matrix during precipitate growth contribute to the lattice strain. In this case, the expected value calculated from literature values is ??=?0.26?±?0.05. Further, the precise evaluation of Pendellösung oscillations in the diffracted Bragg intensity of as-grown wafers reveals a thermal Debye-Waller parameter for the 220 reflection B{sup 220}(293?K) of 0.5582?±?0.0039 Å{sup 2} for a structure factor based on spherically symmetric scattering contributions.

  11. Scanning electron microscopy and energy-dispersive X-ray microanalysis studies of several human calculi containing calcium phosphate crystals.

    PubMed

    Kodaka, T; Debari, K; Sano, T; Yamada, M

    1994-01-01

    Human calcium phosphate calculi: two sialoliths, a urolith, a rhinolith, and a tonsillolith were investigated by scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). The sialoliths and urolith had appositional shells with thick cortices, respectively, around several nuclei composed of calcospherulites and a rubber-film fragment. The rhinolith had a thin cortex with appositional laminations around a glomerulus-like mass of calcified cotton-like strings. The tonsillolith had a rough cortex with appositional laminations. Its porous interior was composed of numerous calcified conglomerates with microorganisms and calcified masses with fine appositional laminations around the conglomerates. The major crystals were identified as biological apatites (AP) with a sand-grain rather than a needle-like shape, and plate-shaped octacalcium phosphate (OCP). The AP deposits of the rhinolith probably were associated with magnesium (Mg) phosphates or contained Mg. No OCP was found in the rhinolith. The AP deposits were mainly formed by extracellular calcification. Hexahedral crystals, identified as Mg-containing whitlockite (WH), were precipitated in the internal spaces of the AP and OCP deposits. The rhinolith nucleus consisted of WH crystal deposits only. PMID:7701299

  12. Benthic algae as monitors of heavy metals in various polluted rivers by Energy Dispersive X-Ray Spectrometer.

    PubMed

    Lai, Sheue-Duan; Chen, Pei-Chung; Hsu, Hoang-Kao

    2003-05-01

    Benthic microalgae assemblages were used as monitors of copper (Cu), zinc (Zn), and chromium (Cr) in various polluted rivers of San-Yeh-Kong, in southern Taiwan, and analyzed using Scanning Electron Microscope and Energy Dispersive X-Ray Spectrometer (SEM-EDS). Under SEM-EDS, the benthic algae from seriously polluted rivers (dominant by the cyanobacteria Oscillatoria chalybea, green algae Euglena acus and diatom Nitzschia palea under light microscopes) revealed the elemental compositions of heavy metals such as Cu, Zn, Cr, Ti, and that of Mg, Al, Si, P, S, Cl, K, Ca, and Fe. In contrast, benthic algae from moderately (dominant by diatoms Cymbella turgidula and Gomphonema globiferm) and lightly polluted river (dominant by diatom Diatoma vulgare) didn't have any heavy metal elements. In addition to the algal samples, unfiltered water and bottom mud were also investigated for comparison. Further experiment involving the benthic algae from seriously polluted station revealed that all dominant species could survive on the 1 mL 60 ppm Cu, 1 mL 60 ppm Zn, and 1 mL 60 ppm Cr separately after five days culture. The data of this preliminary study are sufficient to encourage further experimentation into the potential for detecting benthic algae as a bioindicator under SEM-EDS to provide rapid information about water pollution. PMID:12744437

  13. Characterization of wood dust from furniture by scanning electron microscopy and energy-dispersive x-ray analysis.

    PubMed

    Gómez Yepes, Milena Elizabeth; Cremades, Lázaro V

    2011-01-01

    Study characterized and analyzed form factor, elementary composition and particle size of wood dust, in order to understand its harmful health effects on carpenters in Quindío (Colombia). Once particle characteristics (size distributions, aerodynamic equivalent diameter (D(?)), elemental composition and shape factors) were analyzed, particles were then characterized via scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray analysis (EDXRA). SEM analysis of particulate matter showed: 1) cone-shaped particle ranged from 2.09 to 48.79 µm D(?); 2) rectangular prism-shaped particle from 2.47 to 72.9 µm D(?); 3) cylindrically-shaped particle from 2.5 to 48.79 µm D(?); and 4) spherically-shaped particle from 2.61 to 51.93 µm D(?). EDXRA reveals presence of chemical elements from paints and varnishes such as Ca, K, Na and Cr. SEM/EDXRA contributes in a significant manner to the morphological characterization of wood dust. It is obvious that the type of particles sampled is a complex function of shapes and sizes of particles. Thus, it is important to investigate the influence of particles characteristics, morphology, shapes and D(?) that may affect the health of carpenters in Quindío. PMID:21697619

  14. Fusion Peptides Promote Formation of Bilayer Cubic Phases in Lipid Dispersions. An X-Ray Diffraction Study

    PubMed Central

    Tenchov, Boris G.; MacDonald, Robert C.; Lentz, Barry R.

    2013-01-01

    Small angle x-ray diffraction revealed a strong influence of the N-terminal influenza hemagglutinin fusion peptide on the formation of nonlamellar lipid phases. Comparative measurements were made on a series of three peptides, a 20-residue wild-type X-31 influenza virus fusion peptide, GLFGAIAGFIENGWEGMIDG, and its two point-mutant, fusion-incompetent peptides G1E and G13L, in mixtures with hydrated phospholipids, either dipalmitoleoylphosphatidylethanolamine (DPoPE), or monomethylated dioleoyl phosphatidylethanolamine (DOPE-Me), at lipid/peptide molar ratios of 200:1 and 50:1. All three peptides suppressed the HII phase and shifted the L?–HII transition to higher temperatures, simultaneously promoting formation of inverted bicontinuous cubic phases, QII, which becomes inserted between the L? and HII phases on the temperature scale. Peptide-induced QII had strongly reduced lattice constants in comparison to the QII phases that form in pure lipids. QII formation was favored at the expense of both L? and HII phases. The wild-type fusion peptide, WT-20, was distinguished from G1E and G13L by the markedly greater magnitude of its effect. WT-20 disordered the L? phase and completely abolished the HII phase in DOPE-Me/WT-20 50:1 dispersions, converted the QII phase type from Im3m to Pn3m and reduced the unit cell size from ?38 nm for the Im3m phase of DOPE-Me dispersions to ?15 nm for the Pn3m phase in DOPE-Me/WT-20 peptide mixtures. The strong reduction of the cubic phase lattice parameter suggests that the fusion-promoting WT-20 peptide may function by favoring bilayer states of more negative Gaussian curvature and promoting fusion along pathways involving Pn3m phase-like fusion pore intermediates rather than pathways involving HII phase-like intermediates. PMID:23473485

  15. Dispersion, aberration and deconvolution in multi-wavelength fluorescence images

    Microsoft Academic Search

    B. A. SCALETTAR; J. R. SWEDLOW; J. W. SEDAT; D. A. AGARD

    1996-01-01

    Summary The wavelength dependence of the incoherent point spread function in a wide-field microscope was investigated experimentally. Dispersion in the sample and optics can lead to significant changes in the point spread function as wavelength is varied over the range commonly used in fluorescence microscopy. For a given sample, optical con- ditions can generally be optimized to produce a point

  16. High Resolution Energy Dispersive Spectrometry with Charge-Induced X-Rays: Principles, Comparison with Other Methods, and Possible Applications

    NASA Astrophysics Data System (ADS)

    Pillay, A. E.; Peisach, M.

    1996-06-01

    A novel phenomenon using Charge-Induced X-rays (CHIX) for selective analytical applications recently has come to the fore. The method is a spin-off from the PIXE technique. It utilizes light or heavy charged particles from low energy accelerators for the production of intense X-ray fluxes by the discharge of accumulated potential on insulating targets. Such X-ray fluxes from suitable ionic compounds with comparitively high melting points, such as the metal fluorides, could be harnessed for practical applications of high specificity. The principles of this method, its relative capabilities, and possible practical applications are discussed.

  17. A new method to estimate elastic scattering cross sections in the X-ray region and the associated anomalous dispersion

    Microsoft Academic Search

    D. V. Rao; R. Cesareo; G. E. Gigante

    1998-01-01

    Using nearly monoenergetic unpolarised K? radiation, we have measured the elastic scattering cross sections for Pt, Au and Pb in the energy region 5.41 ? E ? 9.23 keV. The experimental results for Pt, Au and Pb are new. A new X-ray scattering system was assembled using an X-ray tube and secondary targets. In order to improve the peak-to-background ratio

  18. The utility of bronchoalveolar lavage and transbronchial lung biopsy combined with energy-dispersive X-ray analysis in the diagnosis of silicosis

    SciTech Connect

    Nugent, K.M.; Dodson, R.F.; Idell, S.; Devillier, J.R. (Univ. of Texas Health Center, Tyler (USA))

    1989-11-01

    We used analytical electron microscopic techniques, including energy-dispersive X-ray analysis, to evaluate a patient with diffuse infiltrates and a history of silica exposure. We identified silica particles in digested bronchoalveolar lavage fluid, sectioned alveolar macrophages recovered by lavage, and parenchymal specimens obtained by transbronchial biopsy. This analysis confirmed our clinical suspicion (a sporadic case of accelerated silicosis) and eliminated the need for additional, more complicated, diagnostic procedures.

  19. A morphometric and x-ray energy dispersive approach to monitoring pH-altered cadmium toxicity in Anabaena flos-aquae

    Microsoft Academic Search

    L. C. Rai; Thomas E. Jensen; Joseph W. Rachlin

    1990-01-01

    Cadmium toxicity and uptake as influenced by different pH values have been studied in the freshwater cyanobacteriumAnabaena flos-aquae, using the techniques of morphometric analysis, x-ray energy dispersive analysis and atomic absorption spectrophotometry. A general reduction in cell dimension, thylakoid surface area, number and volume of polyhedral bodies, polyphosphate bodies, cyanophycin granules, lipid bodies, membrane limited crystalline inclusions, volume and number

  20. Calcium detection in secretion granules of avian oviduct by scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX)

    SciTech Connect

    Makita, T.; Hatsuoka, M.; Sugi, Y.

    1983-01-01

    Secretion granules in the shell gland, isthmus, and albumin-secreting region of the hen oviduct were analyzed with WET-scanning electron microscopy (SEM) and EDX, a combination of wide-angle backscattered electron detector (BED) and energy-dispersive X-ray microanalyzer (EDX). Glutaraldehyde-fixed but unhydrated, unstained, and uncoated samples were analyzed; Ca was localized in all secretion granules in all three sections of the hen oviduct studied.

  1. Study of the Interaction of ZDDP and Dispersants Using X-ray Absorption Near Edge Structure Spectroscopy—Part 1: Thermal Chemical Reactions

    Microsoft Academic Search

    Z. Zhang; M. Kasrai; G. M. Bancroft; E. S. Yamaguchi

    2003-01-01

    The interactions of ZDDP and different dispersants have been investigated both in oil solutions and on steel substrates at 150–185?°C. X-ray absorption near edge structure (XANES) spectroscopy at P and S L-edge and K-edge has been used to identify the chemical species both in solution and on the surface of the steel. It was found that noticeable ZDDP decomposition in

  2. Characterization of municipal solid waste incineration (MSWI) bottom ash by scanning electron microscopy and quantitative energy dispersive X-ray microanalysis (SEM\\/EDX)

    Microsoft Academic Search

    C. Speiser; T. Baumann; R. Niessner

    2001-01-01

    Scanning electron microscopy (SEM) with energy-dispersive X-ray microanalysis (EDX) is frequently used for morphological\\u000a and qualitative chemical characterization of different materials. The applicability of this method for phase identification,\\u000a is, however, often underestimated. The application of SEM\\/EDX for the characterization of different phases in fresh and altered\\u000a municipal-waste incinerator bottom-ash samples with high lateral resolution is presented. Polished thin sections

  3. Information-theoretical feature selection using data obtained by Scanning Electron Microscopy coupled with and Energy Dispersive X-ray spectrometer for the classification of glass traces

    Microsoft Academic Search

    Daniel Ramos; Grzegorz Zadora

    2011-01-01

    In this work, a selection of the best features for multivariate forensic glass classification using Scanning Electron Microscopy coupled with an Energy Dispersive X-ray spectrometer (SEM–EDX) has been performed. This has been motivated by the fact that the databases available for forensic glass classification are sparse nowadays, and the acquisition of SEM–EDX data is both costly and time-consuming for forensic

  4. Characterization of the interphase in an aluminium\\/epoxy joint by using controlled pressure scanning electron microscopy coupled with an energy dispersive X-ray spectrometer

    Microsoft Academic Search

    Caroline Sperandio; Claire Arnoult; Abdelghani Laachachi; Jean Di Martino; David Ruch

    2010-01-01

    The aim of this work is to introduce the use of low vacuum scanning electron microscopy (LVSEM) coupled with an X-ray energy dispersive spectrometer (EDS) in the field of structural adhesives, more precisely aluminium\\/epoxy resin assembly. Such assembly is characterized by the creation of an interphase resulting from the metal diffusion inside the resin during cross-linking. As the performance of

  5. MATHEMATICAL TECHNIQUES FOR X-RAY ANALYZERS

    EPA Science Inventory

    Mathematical techniques and subsequent computer software were developed to process energy-dispersive x-ray fluorescence spectra for elemental analysis of airborne particulate matter collected on filters. The research concerned two areas: (1) determination of characteristic x-ray ...

  6. Rigorous integral method in application to computing diffraction on relief gratings working in wavelength range from microwaves to x ray

    NASA Astrophysics Data System (ADS)

    Goray, Leonid I.

    1995-09-01

    Application of rigorous integral method for computing the efficiency of arbitrary profile relief gratings used in all the optical spectral range is presented in this paper. The main progress of the method and the programs lays in numerical solution algorithm. In particular, an approximation of Green-function and its normal derivative is used providing a sufficient accuracy for common practice simultaneously with satisfactory computation time. There is a very important peculiarity of the algorithm, namely both distribution of points of collocation and choice of the number of terms in Green-function expansion are used. These characteristics are different for each special case: perfect conductivity, finite conductivity, transmission gratings and gratings for X-ray and XUV. Such programs can be used as a mathematical model to design and calculate complex multielement optical systems with diffraction gratings.

  7. Debris of potassium-magnesium silicate glass generated by femtosecond laser-induced ablation in air: An analysis by near edge X-ray absorption spectroscopy, micro Raman and energy dispersive X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Grehn, M.; Seuthe, T.; Reinhardt, F.; Höfner, M.; Griga, N.; Eberstein, M.; Bonse, J.

    2014-05-01

    The redeposited material (debris) resulting from ablation of a potassium-magnesium silicate glass upon scanning femtosecond laser pulse irradiation (130 fs, 800 nm) in air environment is investigated by means of three complementary surface analytical methods. Changes in the electronic band structure of the glass constituent Magnesium (Mg) were identified by X-ray Absorption Near Edge Structure spectroscopy (XANES) using synchrotron radiation. An up-shift of ?0.8 eV of a specific Magnesium K-edge absorption peak in the spectrum of the redeposited material along with a significant change in its leading edge position was detected. In contrast, the surface left after laser ablation exhibits a downshift of the peak position by ?0.9 eV. Both observations may be related to a change of the Mg coordinative state of the laser modified/redeposited glass material. The presence of carbon in the debris is revealed by micro Raman spectroscopy (?-RS) and was confirmed by energy dispersive X-ray spectroscopy (EDX). These observations are attributed to structural changes and chemical reactions taking place during the ablation process.

  8. Synchrotron radiation total reflection X-ray fluorescence and energy dispersive X-ray fluorescence analysis on AP1™ films applied to the analysis of trace elements in metal alloys for the construction of nuclear reactor core components: a comparison

    NASA Astrophysics Data System (ADS)

    Pepponi, G.; Wobrauschek, P.; Hegedüs, F.; Streli, C.; Zöger, N.; Jokubonis, C.; Falkenberg, G.; Grimmer, H.

    2001-11-01

    Synchrotron radiation induced total reflection X-ray fluorescence and conventional 45° energy dispersive X-ray fluorescence analysis using a 150-nm-thick AP1™ film as sample carrier have been exploited for the elemental analysis of traces in alloys used for the construction of reactor core components of nuclear power plants. Both techniques are well suited for the analysis since they require a low amount of sample (?l), important on one hand because of the limited disposal and on the other hand because of its high specific activity. The methods provide a very low background due to the total reflection phenomenon in TXRF and the thin AP1™ film sample support, respectively. The employment of synchrotron radiation was necessary since there are no laboratory sources which can deliver a collimated beam of the energy and intensity needed to excite the K-shell of the rare earth elements, allowing the achievement of minimum detection limits relevant for the proposed purpose (ng/g range). Moreover, the linear polarization of synchrotron radiation combined with a side-looking detection geometry manages to reduce the scattering due to the remaining matrix of the analyzed samples. Detection limits for Nb and for some of the rare earth elements (pg range for absolute detection limits and ng-?g/g range for concentration detection limits) obtained with the two techniques are presented and the two approaches are compared.

  9. Building X-ray lasers

    NASA Astrophysics Data System (ADS)

    2010-12-01

    The SLAC Linac Coherent Light Source is now the world's brightest source of coherent ångström-wavelength X-rays. Paul Emma, the man who made this achievement possible, spoke to Nature Photonics about the challenges involved.

  10. Diffraction efficiency of 200-nm-period critical-angle transmission gratings in the soft x-ray and extreme ultraviolet wavelength bands

    SciTech Connect

    Heilmann, Ralf K.; Ahn, Minseung; Bruccoleri, Alex; Chang, Chih-Hao; Gullikson, Eric M.; Mukherjee, Pran; Schattenburg, Mark L.

    2011-04-01

    We report on measurements of the diffraction efficiency of 200-nm-period freestanding blazed transmission gratings for wavelengths in the 0.96 to 19.4 nm range. These critical-angle transmission (CAT) gratings achieve highly efficient blazing over a broad band via total external reflection off the sidewalls of smooth, tens of nanometer thin ultrahigh aspect-ratio silicon grating bars and thus combine the advantages of blazed x-ray reflection gratings with those of more conventional x-ray transmission gratings. Prototype gratings with maximum depths of 3.2 and 6 {mu}m were investigated at two different blaze angles. In these initial CAT gratings the grating bars are monolithically connected to a cross support mesh that only leaves less than half of the grating area unobstructed. Because of our initial fabrication approach, the support mesh bars feature a strongly trapezoidal cross section that leads to varying CAT grating depths and partial absorption of diffracted orders. While theory predicts broadband absolute diffraction efficiencies as high as 60% for ideal CAT gratings without a support mesh, experimental results show efficiencies in the range of {approx}50-100% of theoretical predictions when taking the effects of the support mesh into account. Future minimization of the support mesh therefore promises broadband CAT grating absolute diffraction efficiencies of 50% or higher.

  11. Precise measurements of X-ray spectral line wavelengths for multicharged ions in a recombining laser plasma

    NASA Astrophysics Data System (ADS)

    Briunetkin, B. A.; Pikuz, S. A.; Skobelev, I. Iu.; Faenov, A. Ia.; Khabibulaev, B. K.; Ermatov, Sh. A.

    1992-09-01

    A method for improving the accuracy of the measurement of spectral line wavelengths of multicharged ions has been proposed and experimentally implemented. The method is based on the spectral recording of radiation from a recombining laser plasma. The wavelengths of series of lines for F VIII, F IX ions were measured with a relative error, Delta lambda/lambda, of (6-8) x 10 exp -5.

  12. Electron density distribution of Ba1-xKxBiO3 (x = 0.43) by ultra-short-wavelength x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Takahashi, Yasuhiko; Ji, Xioali; Nishio, Taichiro; Uwe, Hiromoto; Ohshima, Ken-ichi

    2002-06-01

    The crystal structure and electron density distribution (EDD) of superconducting Ba0.57K0.43BiO3 have been studied by the maximum-entropy method using ultra-short-wavelength x-ray diffraction data for a single crystal at 295 and 108 K. It is found that the bonding between the Bi and O atoms is covalent, though there is no overlapping of electron density between (Ba, K) and O atoms. The EDD around O atoms shows spatial anisotropy and the result is in agreement with anisotropic thermal motion of O atoms. No peculiar change of chemical bonding nature appears, comparing the EDD at 295 K with that at 108 K. The calculated EDD for cubic BaBiO3 using the first-principles full-potential linearized augmented plane-wave method is compared with the experimental EDD for Ba0.57K0.43BiO3.

  13. Dispersive x-ray absorption studies at the Fe K-edge on the iron chalcogenide superconductor FeSe under pressure.

    PubMed

    Bendele, M; Marini, C; Joseph, B; Simonelli, L; Dore, P; Pascarelli, S; Chikovani, M; Pomjakushina, E; Conder, K; Saini, N L; Postorino, P

    2013-10-23

    The local structure and the electronic properties of FeSe under hydrostatic pressure were studied by means of dispersive x-ray absorption measurements at the Fe K-edge. The pressure dependence of the x-ray absorption near edge structure features seems to follow the behavior of the superconducting transition temperature Tc. The local structure, that has an important impact on the superconducting properties, appears to fall into two regimes: the pressure dependence of the Fe-Fe bond distance shows a clear change in the compressibility at p ? 5 GPa; in contrast, the Fe-Se bond distance decreases continuously with increasing pressure with a lower compressibility than the Fe-Fe bond. The results suggest that the pressure dependent changes in Tc of FeSe are closely related to the changes in local structure. PMID:24084478

  14. Validation of quick measurement of mineral nutrients in milk powders: comparison of energy dispersive X-ray fluorescence with inductively coupled plasma-optical emission spectroscopy and potentiometry reference methods

    Microsoft Academic Search

    Loïc Perring; Joëlle Blanc

    2008-01-01

    Energy dispersive X-ray fluorescence method is a good candidate to be implemented close to production lines of fortified milk\\u000a powders, in order to ensure their quality control. In this study an energy dispersive X-ray fluorescence (EDXRF) method was\\u000a tested as a simple, fast (< 8 min\\/pellet) and simultaneous method for the quantification of a series of macroelements (Na,\\u000a Mg, P,

  15. Accurate calibration for the quantification of the Al content in AlGaN epitaxial layers by energy-dispersive X-ray spectroscopy in a Transmission Electron Microscope

    NASA Astrophysics Data System (ADS)

    Amari, H.; Lari, L.; Zhang, H. Y.; Geelhaar, L.; Chèze, C.; Kappers, M. J.; McAleese, C.; Humphreys, C. J.; Walther, T.

    2011-11-01

    Since the band structure of group III- nitrides presents a direct electronic transition with a band-gap energy covering the range from 3.4 eV for (GaN) to 6.2 eV (for AlN) at room temperature as well as a high thermal conductivity, aluminium gallium nitride (AlGaN) is a strong candidate for high-power and high-temperature electronic devices and short-wavelength (visible and ultraviolet) optoelectronic devices. We report here a study by energy-filtered transmission electron microscopy (EFTEM) and energy-dispersive X-ray spectroscopy (EDXS) of the micro structure and elemental distribution in different aluminium gallium nitride epitaxial layers grown by different research groups. A calibration procedure is out-lined that yields the Al content from EDXS to within ~1 at % precision.

  16. Center for X-Ray Optics, 1986

    SciTech Connect

    Not Available

    1987-07-01

    The Center for X-Ray Optics has made substantial progress during the past year on the development of very high resolution x-ray technologies, the generation of coherent radiation at x-ray wavelengths, and, based on these new developments, had embarked on several scientific investigations that would not otherwise have been possible. The investigations covered in this report are topics on x-ray sources, x-ray imaging and applications, soft x-ray spectroscopy, synchrotron radiation, advanced light source and magnet structures for undulators and wigglers. (LSP)

  17. ENERGY DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF DUST COLLECTED USING A VERTICAL ELUTRIATOR COTTON DUST SAMPLER

    EPA Science Inventory

    X-ray fluorescence (XRF) spectroscopy has been used to analyze trace element concentrations in cotton dusts collected on verticle elutriator filter media. Twenty-three samples collected from ten bales of cotton processed in a model card room have been analyzed. The major elements...

  18. X-ray scattering in X-ray fluorescence spectra with X-ray tube excitation – Modelling, experiment, and Monte-Carlo simulation

    Microsoft Academic Search

    V.-D. Hodoroaba; M. Radtke; L. Vincze; V. Rackwitz; D. Reuter

    2010-01-01

    X-ray scattering may contribute significantly to the spectral background of X-ray fluorescence (XRF) spectra. Based on metrological measurements carried out with a scanning electron microscope (SEM) having attached a well characterised X-ray source (polychromatic X-ray tube) and a calibrated energy dispersive X-ray spectrometer (EDS) the accuracy of a physical model for X-ray scattering is systematically evaluated for representative samples. The

  19. Chemometric classification of gunshot residues based on energy dispersive X-ray microanalysis and inductively coupled plasma analysis with mass-spectrometric detection

    NASA Astrophysics Data System (ADS)

    Steffen, S.; Otto, M.; Niewoehner, L.; Barth, M.; Bro¿?ek-Mucha, Z.; Biegstraaten, J.; Horváth, R.

    2007-09-01

    A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups: 'gunshot residue characteristic', 'consistent with gunshot residue' and environmental particles, respectively. Potential gunshot residue particles are manually checked and - if necessary - confirmed by the operating forensic scientist. As there are continuing developments on the ammunition market worldwide, it becomes more and more difficult to assign a detected particle to a particular ammunition brand. As well, the differentiation towards environmental particles similar to gunshot residue is getting more complex. To keep external conditions unchanged, gunshot residue particles were collected using a specially designed shooting device for the test shots revealing defined shooting distances between the weapon's muzzle and the target. The data obtained as X-ray spectra of a number of particles (3000 per ammunition brand) were reduced by Fast Fourier Transformation and subjected to a chemometric evaluation by means of regularized discriminant analysis. In addition to the scanning electron microscopy in combination with energy dispersive X-ray microanalysis results, isotope ratio measurements based on inductively coupled plasma analysis with mass-spectrometric detection were carried out to provide a supplementary feature for an even lower risk of misclassification.

  20. Misidentification of major constituents by automatic qualitative energy dispersive X-ray microanalysis: a problem that threatens the credibility of the analytical community.

    PubMed

    Newbury, Dale E

    2005-12-01

    Automatic qualitative analysis for peak identification is a standard feature of virtually all modern computer-aided analysis software for energy dispersive X-ray spectrometry with electron excitation. Testing of recently installed systems from four different manufacturers has revealed the occasional occurrence of misidentification of peaks of major constituents whose concentrations exceeded 0.1 mass fraction (10 wt%). Test materials where peak identification failures were observed included ZnS, KBr, FeS2, tantalum-niobium alloy, NIST Standard Reference Material 482 (copper-gold alloy), Bi2Te3, uranium-rhodium alloys, platinum-chromium alloy, GaAs, and GaP. These misidentifications of major constituents were exacerbated when the incident beam energy was 10 keV or lower, which restricted or excluded the excitation of the high photon energy K- and L-shell X-rays where multiple peaks, for example, Kalpha (K-L2,3)-Kbeta (K-M2,3); Lalpha (L3-M4,5)-Lbeta (L2-M4)-Lgamma (L2-N4), are well resolved and amenable to identification with high confidence. These misidentifications are so severe as to properly qualify as blunders that present a serious challenge to the credibility of this critical analytical technique. Systematic testing of a peak identification system with a suite of diverse materials can reveal the specific elements and X-ray peaks where failures are likely to occur. PMID:17481333

  1. Ultrastructural differentiation within the central nervous system between indolamines and catecholamines by energy dispersive X-ray analysis following paraformaldehyde pretreatment

    SciTech Connect

    McClung, R.E.; Wood, J.

    1983-08-01

    Dense bodies containing high amounts of chrome were localized in the perikarya of substantia nigra and dorsal raphe neurons following the cytochemical reaction of endogenous dopamine and serotonin (respectively) with glutaraldehyde-dichromate (GDC). Energy dispersive X-ray analysis of these bodies revealed chrome levels two to four times higher than those recorded from the cytoplasmic background. Pretreatment with paraformaldehyde blocked the GDC reaction within the dense bodies in the substantia nigra (chrome levels similar to background), while the chrome levels in the dense bodies of the raphe neurons remained elevated. This demonstrates that pretreatment with paraformaldehyde allows selective localization of central nervous system serotonin stores by the GDC technique.

  2. A general Monte Carlo simulation of energy dispersive X-ray fluorescence spectrometers — Part 5. Polarized radiation, stratified samples, cascade effects, M-lines

    NASA Astrophysics Data System (ADS)

    Schoonjans, Tom; Vincze, Laszlo; Solé, Vicente Armando; Sanchez del Rio, Manuel; Brondeel, Philip; Silversmit, Geert; Appel, Karen; Ferrero, Claudio

    2012-04-01

    A general Monte Carlo code for the simulation of energy dispersive X-ray fluorescence (ED-XRF) spectrometers is presented. As a significant extension to existing Monte Carlo codes, dedicated to ED-XRF spectrometers, the new code includes several unique features such as the simulation of M-lines and cascade effects. The detector response function was extended with fluorescence and Compton escape peaks, as well as with pulse pile-up. A full description of the underlying algorithms is given. The software was validated by means of comparison with experimental spectra of standard reference materials collected at the synchrotron XRF-microprobe installed at HASYLAB Beamline L, Hamburg, Germany.

  3. Determination of the x-ray anomalous dispersion of titanium made with a titanium-carbon layered synthetic microstructure

    Microsoft Academic Search

    William K. Warburton; James H. Underwood

    1984-01-01

    Layered synthetic microstructures (LSM's) are manufactured structures consisting of alternating layers of two materials, A and B, that have been deposited from a vapor to obtain uniform layer thicknesses t\\/sub a\\/ and t\\/sub b\\/. As a consequence, LSM's diffract x rays as if they had a characteristic superlattice parameter d = t\\/sub a\\/+t\\/sub b\\/. The details of this reflection process

  4. Assay of elements contained in human hair shafts by energy-dispersive analysis of X-rays (EDAX)

    Microsoft Academic Search

    A. Dupré; P. Touron; J. Daste; R. Victor

    1981-01-01

    The purpose of the present work was to qualitatively and semi-quantitativ ely determine the elements involved in the composition of normal hair shafts with the method of energy-dispersiv e analysis of X-rays (EDAX). Hair samples were removed from 70 subjects and analyzed with no prior treatment. The population sampled wa s composed of 70 subjects of both sexes in an

  5. Diagnostic Spectrometers for High Energy Density X-Ray Sources

    SciTech Connect

    Hudson, L. T.; Henins, A. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Seely, J. F.; Holland, G. E. [Naval Research Laboratory, Space Science Division, Washington DC 20375 (United States)

    2007-08-02

    A new generation of advanced laser, accelerator, and plasma confinement devices are emerging that are producing extreme states of light and matter that are unprecedented for laboratory study. Examples of such sources that will produce laboratory x-ray emissions with unprecedented characteristics include megajoule-class and ultrafast, ultraintense petawatt laser-produced plasmas; tabletop high-harmonic-generation x-ray sources; high-brightness zeta-pinch and magnetically confined plasma sources; and coherent x-ray free electron lasers and compact inverse-Compton x-ray sources. Characterizing the spectra, time structure, and intensity of x rays emitted by these and other novel sources is critical to assessing system performance and progress as well as pursuing the new and unpredictable physical interactions of interest to basic and applied high-energy-density (HED) science. As these technologies mature, increased emphasis will need to be placed on advanced diagnostic instrumentation and metrology, standard reference data, absolute calibrations and traceability of results.We are actively designing, fabricating, and fielding wavelength-calibrated x-ray spectrometers that have been employed to register spectra from a variety of exotic x-ray sources (electron beam ion trap, electron cyclotron resonance ion source, terawatt pulsed-power-driven accelerator, laser-produced plasmas). These instruments employ a variety of curved-crystal optics, detector technologies, and data acquisition strategies. In anticipation of the trends mentioned above, this paper will focus primarily on optical designs that can accommodate the high background signals produced in HED experiments while also registering their high-energy spectral emissions. In particular, we review the results of recent laboratory testing that explores off-Rowland circle imaging in an effort to reclaim the instrumental resolving power that is increasingly elusive at higher energies when using wavelength-dispersive techniques. These efforts inform the optimization of diagnostic designs that will permit acquisition of high-resolution, hard x-ray spectra in the HED environment.

  6. Laboratory x-ray lasers

    SciTech Connect

    Matthews, D.L.

    1989-08-01

    One of the most innovative spinoffs of ICF technology and physics has been the development of the x-ray wavelength laser. The first incontrovertible demonstration of this type of laser came from LLNL in 1984 using the Novette laser to pump a selenium foil target. The power and energy of Novette were then needed to produce a column of plasma of sufficient length to achieve a sufficient gainlength product ({approximately}5.5, this corresponds to an amplification of {approximately}250X) that could unquestionably illustrate the lasing effect. LLNL ICF expertise was also required to develop time-resolved spectrometers used to view the lasing transitions at {approximately}20 nm, a region of the XUV spectrum normally dominated by high backgrounds. The design of the x-ray laser amplifier, which required maintaining nonequilibrium level populations in a tailored plasma having the proper conditions for gain and x-ray laser beam propagation, was accomplished with modified versions of ICF kinetics and hydrodynamics codes. Since the first demonstration, our progress in the development of the x-ray laser has been rapid. New achievements include production of megawatt power levels at 20 nm, amplified spontaneous emission levels approaching saturation intensity (GL {approximately}17 {at} 20 nm, efficiency (x-ray laser energy/pump energy) {approximately}10{sup {minus}6}), the demonstration of double and triple pass amplification (hinting at the possibility of producing x-ray wavelength resonators), the focusing of x-ray lasers to pump other types of lasers and the first demonstration of an x-ray hologram produced by an x-ray laser. The generation of amplification at ever shorter wavelength is possible using various types of inversion schemes. We depict below this progress benchmarked against production of gain in the water window (2.2 to 4.4 nm,), where applications to biological imaging may be facilitated.

  7. Grazing-emission X-ray fluorescence spectrometry; principles and applications

    NASA Astrophysics Data System (ADS)

    de Bokx, P. K.; Kok, Chr.; Bailleul, A.; Wiener, G.; Urbach, H. P.

    1997-07-01

    In grazing-emission X-ray fluorescence spectrometry (GEXRF), the sample is irradiated at approximately normal incidence, and only that part of the fluorescence radiation is detected that is emitted at grazing angles. This configuration allows the use of wavelength-dispersive detection. This type of detection has the advantages of substantially better energy resolution at longer wavelengths (light elements, L and M lines of heavier elements) and a much larger dynamic range than the energy-dispersive detectors currently used in grazing X-ray techniques. Typical examples are presented of applications that are made possible by this new technique.

  8. Relationship between dislocations and residual stresses in cold-drawn pearlitic steel analyzed by energy-dispersive X-ray diffraction

    SciTech Connect

    Sato, Shigeo, E-mail: s.sato@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Wagatsuma, Kazuaki [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Suzuki, Shigeru [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); Kumagai, Masayoshi; Imafuku, Muneyuki [Faculty of Engineering, Tokyo City University, Tokyo 158-8557 (Japan); Tashiro, Hitoshi [Gyoda 361-0011 (Japan); Kajiwara, Kentaro [Japan Synchrotron Radiation Research Institute, Sayo 679-5198 (Japan); Shobu, Takahiasa [Japan Atomic Energy Agency, Sayo 679-5184 (Japan)

    2013-09-15

    We analyzed the dislocation distribution of cold-drawn pearlitic-steel wire by using the line-profile analysis based on the energy dispersive X-ray diffraction (EDXD). Although this line-profile analysis requires a high resolution in reciprocal space, the resolution for EDXD is generally poor due to the energy resolution of the detector. Our analysis demonstrated that the resolution in the reciprocal space can be maximized at small scattering angles. Using the line-profile analysis based on the EDXD, the microstructural parameters such as the crystallite size and the dislocation density of the ferrite phase in the pearlitic steel were successfully analyzed. In addition, the distribution of the residual stress of the ferrite phase of a pearlitic steel wire was also analyzed using the EDXD measurement. - Highlights: • Energy dispersive X-ray diffraction is applied to the line-profile analysis. • Distribution of dislocations in ferrite in the pearlitic steel wire is analyzed. • Relationship between dislocations and residual stress is discussed.

  9. Skull x-ray

    MedlinePLUS

    X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... You will be asked to lie on the x-ray table or sit in a chair. Your ... there is little or no discomfort during an x-ray. If there is a head injury , positioning ...

  10. Hard X-ray emission from high-intensity femtosecond laser plasma and its application to X-ray diffraction

    Microsoft Academic Search

    S. Grantham; C. Kim; C. DePriest; M. Richardson

    1998-01-01

    We present Laue diffraction experiments using a fs laser plasma X-ray ultrashort pulse source as preliminary experiments for time resolved X-ray Laue diffraction. The Laue method in X-ray diffraction experiments employs an X-ray beam consisting of a range of wavelengths to illuminate a stationary crystal

  11. X-ray imaging of dispersive charge modes in a doped Mott insulator near the antiferromagnetic/superconductor transition

    SciTech Connect

    Li, Y.W.; Qian, D.; Wray, L.; Hsieh, D.; Xia, Y.; Kaga, Y.; Sasagawa, T.; Takagi, H.; Markiewicz, R.S.; Bansil, A.; Eisaki, H.; Uchida, S.; Hasan, M.Z. (U of Tokyo); (AIST); (Princeton); (NEU)

    2009-01-12

    Momentum-resolved inelastic resonant x-ray scattering is used to map the doping evolution of bulk electronic modes in the doped Mott insulator class Nd{sub 2-x}Ce{sub x}CuO{sub 4}. As the doping induced antiferromagnet/superconductor (AFM/SC) transition is approached, we observe an anisotropic redistribution of the spectral weight of collective excitations over a large energy scale along the {Gamma} {yields} ({pi},{pi}) direction, whereas the modes exhibit broadening (-1 eV) with relatively little softening along {Gamma} {yields} ({pi},0) with respect to the parent Mott state (x=0). Our study reveals a closing of the charge gap in the vicinity of the zone center even though the mode softening and spectral redistribution involve an unusually large energy scale over the full Brillouin zone. The collective behavior of modes in the vicinity of the AFM/SC critical transition is demonstrated.

  12. X-ray lithography using holographic images

    DOEpatents

    Howells, Malcolm R. (Berkeley, CA); Jacobsen, Chris (Sound Beach, NY)

    1995-01-01

    A non-contact X-ray projection lithography method for producing a desired X-ray image on a selected surface of an X-ray-sensitive material, such as photoresist material on a wafer, the desired X-ray image having image minimum linewidths as small as 0.063 .mu.m, or even smaller. A hologram and its position are determined that will produce the desired image on the selected surface when the hologram is irradiated with X-rays from a suitably monochromatic X-ray source of a selected wavelength .lambda.. On-axis X-ray transmission through, or off-axis X-ray reflection from, a hologram may be used here, with very different requirements for monochromaticity, flux and brightness of the X-ray source. For reasonable penetration of photoresist materials by X-rays produced by the X-ray source, the wavelength X, is preferably chosen to be no more than 13.5 nm in one embodiment and more preferably is chosen in the range 1-5 nm in the other embodiment. A lower limit on linewidth is set by the linewidth of available microstructure writing devices, such as an electron beam.

  13. Fast multi-wavelength broad-band and QPO variability in a black hole X-ray binary: accretion flow and/or a jet origin?

    NASA Astrophysics Data System (ADS)

    Kalamkar, M.; Casella, P.; O'Brien, K.; Uttley, P.; Maccarone, T.

    2015-07-01

    Fast variability in X-ray binaries has been studied for many decades, which is associated with accretion flows (in X-rays) and recently confirmed from jets (at least in the infra-red band). I will present results of observations of a black hole X-ray binary in hard state with simultaneous coverage in X-ray, optical and infra-red bands. A Quasi Periodic Oscillation (QPO) is detected for the first time in infra-red. Interestingly, the QPO is also detected in optical and the frequency in both these bands is half the frequency of the QPO in X-rays (classified as type-C) in the broad 0.3-60 keV range. The infra-red power spectrum also exhibits broad-band noise similar to the X-ray power spectrum and is correlated. Hence, we see strong correlated variability in the emission from the accretion disk, corona/hot flow and the jet. With the known origin of X-ray variability in accretion flows, I will discuss if this can manifest itself in jets providing a mechanism for jet variability in the framework of existing models (e.g., Ingram & Done 2011, Veledina et al. 2013, Drappeau et al. 2015). This will provide strong constraints on the structure and geometry of these systems and insight into their disk-jet coupling.

  14. Scanning-free grazing emission x-ray fluorescence by means of an angular dispersive arrangement with a two-dimensional position-sensitive area detector

    NASA Astrophysics Data System (ADS)

    Kayser, Y.; Szlachetko, J.; Sà, J.

    2013-12-01

    We report on the application of a two-dimensional position-sensitive area detector towards grazing emission x-ray fluorescence (GEXRF) spectroscopy. GEXRF allows for surface-sensitive studies with nanometer-scale accuracy in the depth direction by measuring the intensity variation of an x-ray fluorescence line with the grazing emission angle. The presented experimental setup is based on a fixed sample-detector arrangement and does not require any moving components. We show that the dispersion of the grazing emission angle along a position-sensitive detector allows to acquire with an excellent angular resolution a full GEXRF profile in a single measurement. Moreover, the use of a two-dimensional detector allows to perform experiments with an increased solid angle of detection per emission angle. This results in combination with the nonsequential and simultaneous acquisition of the GEXRF profiles of different emission lines in considerably reduced acquisition times. The realization, the demands, and the main characteristics of the scanning-free GEXRF setup will be presented. A few experimental examples will serve to illustrate the analytical possibilities offered by the presented setup.

  15. Allowance for the dispersity of a powder sample on the basis of two line intensities of the target element in x-ray fluorescence analysis

    SciTech Connect

    Duimakaeva, T.G.; Tarnopol`skii, M.G.; Duimakaev, Sh.I.; Karmanov, V.I.; Shpolyanskii, A.Y. [State Univ., Rostov-on-Don (Russian Federation)

    1994-06-01

    The situation where a heterogeneous powder sample contains adjacent elements A and B (e.g., Zn-Cu, Cu-Ni, or Fe-Mn), or element B is specifically added to the sample, is frequently encountered in analytical practice. It has been shown that the effective grain diameter D of the component {alpha} containing element A can, in principle, be taken into account in this situation when the intensities of two x-ray fluorescence lines of element A and a fluorescence line of element B are known. The given analysis example has limited application [e.g., the analysis of industrial heterogeneous powder materials having slightly different elemental composition (batch testing) and already containing element B]. However, the approach developed here can also be applied to samples having a variable filler composition (but preserving, of course, the condition of a constant level c{sub B}, i.e., remaining within the framework of the additive method or the internal standard method). The reported investigation shows that the ratio of the intensities of two fluorescence lines of the target element holds considerable promise in regard to the problem of taking into account the dispersity of a powder sample in x-ray fluorescence analysis.

  16. Iron speciation of airborne subway particles by the combined use of energy dispersive electron probe X-ray microanalysis and Raman microspectrometry.

    PubMed

    Eom, Hyo-Jin; Jung, Hae-Jin; Sobanska, Sophie; Chung, Sang-Gwi; Son, Youn-Suk; Kim, Jo-Chun; Sunwoo, Young; Ro, Chul-Un

    2013-11-01

    Quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA), known as low-Z particle EPMA, and Raman microspectrometry (RMS) were applied in combination for an analysis of the iron species in airborne PM10 particles collected in underground subway tunnels. Iron species have been reported to be a major chemical species in underground subway particles generated mainly from mechanical wear and friction processes. In particular, iron-containing particles in subway tunnels are expected to be generated with minimal outdoor influence on the particle composition. Because iron-containing particles have different toxicity and magnetic properties depending on their oxidation states, it is important to determine the iron species of underground subway particles in the context of both indoor public health and control measures. A recently developed analytical methodology, i.e., the combined use of low-Z particle EPMA and RMS, was used to identify the chemical species of the same individual subway particles on a single particle basis, and the bulk iron compositions of airborne subway particles were also analyzed by X-ray diffraction. The majority of airborne subway particles collected in the underground tunnels were found to be magnetite, hematite, and iron metal. All the particles collected in the tunnels of underground subway stations were attracted to permanent magnets due mainly to the almost ubiquitous ferrimagnetic magnetite, indicating that airborne subway particles can be removed using magnets as a control measure. PMID:24069900

  17. Spatially resolved energy dispersive x-ray diffraction (EDXRD) as a tool for nondestructively providing phase composition depth profiles on cement and other materials

    SciTech Connect

    Wilkinson, A.P.; Jupe, A.C.; Kurtis, K.E.; Naik, N.N.; Stock, S.R.; Lee, P.L. (NWU); (GIT)

    2005-05-25

    The presence of sulfates in water or soils surrounding portland cement concrete structures leads to progressive degradation. Spatially resolved energy dispersive diffraction (EDXRD) in combination with computed microtomography ({mu}CT) and mechanical measurements can provide the information needed to understand, in detail, the degradation mechanisms that are associated with sulfate attack and to validate accelerated test methods used to evaluate the sulfate resistance of cements. Highly penetrating, high-energy X-rays from synchrotron sources allow the use of EDXRD to nondestructively determine depth profiles for the crystalline phases in the cement paste specimens several millimeters below the sample surface. These depth profiles, and how they vary with sulfate exposure conditions and duration, can be correlated with mechanical changes and the crack patterns seen in the microtomographs. Spatially resolved EDXRD is in principle useful for phase composition mapping and depth profiling in a wide range of materials where the attenuation of high energy x-rays is not extreme. Suitable materials include many ceramic compositions.

  18. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1991-01-01

    The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

  19. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1990-01-01

    The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

  20. X-ray universe

    SciTech Connect

    Tucker, W.; Giacconi, R.

    1985-01-01

    This book is a selective and personal history of x-ray astronomy. The x-ray universe is considered along with the sensible world, historical aspects regarding the discovery and utilization of x-rays, the pioneers of x-ray astronomy, the discovery of an x-ray star, the riddle of the x-ray stars, developments leading to the Uhuru (x-ray Explorer) satellite and the study of neutron stars and black holes, the x-ray sky, a telescope for x-rays, the Einstein observatory (HEAO-2), stellar coronas and supernovas, active galaxies and quasars, clusters of galaxies and the missing mass, and the cosmic x-ray background. Attention is also given to NASA's Advanced x-Ray Astrophysics Facility, which will open a permanent window on the x-ray universe.

  1. Joint x-ray

    MedlinePLUS

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  2. THE STRUCTURE OF THE ACCRETION DISK IN THE ACCRETION DISK CORONA X-RAY BINARY 4U 1822-371 AT OPTICAL AND ULTRAVIOLET WAVELENGTHS

    SciTech Connect

    Bayless, Amanda J.; Robinson, Edward L.; Cornell, Mark E. [Department of Astronomy, University of Texas at Austin, 1 University Station, Austin, TX 78712-0259 (United States); Hynes, Robert I. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Ashcraft, Teresa A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States)

    2010-01-20

    The eclipsing low-mass X-ray binary 4U 1822-371 is the prototypical accretion disk corona (ADC) system. We have obtained new time-resolved UV spectroscopy of 4U 1822-371 with the Advanced Camera for Surveys/Solar Blind Channel on the Hubble Space Telescope and new V- and J-band photometry with the 1.3 m SMARTS telescope at Cerro Tololo Inter-American Observatory. We use the new data to construct its UV/optical spectral energy distribution and its orbital light curve in the UV, V, and J bands. We derive an improved ephemeris for the optical eclipses and confirm that the orbital period is changing rapidly, indicating extremely high rates of mass flow in the system, and we show that the accretion disk in the system has a strong wind with projected velocities up to 4000 km s{sup -1}. We show that the disk has a vertically extended, optically thick component at optical wavelengths. This component extends almost to the edge of the disk and has a height equal to approx0.5 of the disk radius. As it has a low brightness temperature, we identify it as the optically thick base of a disk wind, not as the optical counterpart of the ADC. Like previous models of 4U 1822-371, ours needs a tall obscuring wall near the edge of the accretion disk, but we interpret the wall as a layer of cooler material at the base of the disk wind, not as a tall, luminous disk rim.

  3. Simultaneous determination of cobalt, copper and zinc by energy dispersive X-ray fluorescence spectrometry after preconcentration on PAR-loaded ion-exchange resin.

    PubMed

    Jiang, Zi-Tao; Yu, Jimmy C; Liu, Ho-Yan

    2005-07-01

    A sensitive method for the preconcentration and determination of trace amounts of Co, Cu and Zn by energy-dispersive X-ray fluorescence spectrometry (EDXRF) has been developed. The method is based on the fact that 4-(2-pyridylazo)-resorcinol (PAR) loaded Dowex anion-exchange resin (PAR-resin) can effectively adsorb Co, Cu and Zn at pH 9.0 to form PAR-metal complexes. The detection limits for Co, Cu and Zn were 1.53, 0.31 and 0.21 ppb, respectively. The precisions for five replicate measurements of the three metals were 3.4, 2.7 and 2.1% RSD, and the calibration curves were linear up to 75 microg with correlation coefficients of 0.9975, 0.9980 and 0.9985, respectively. The method was successfully applied for the simultaneous determination of Co, Cu and Zn in seawater samples at ppb levels. PMID:16038508

  4. Statistical assessment of heavy metal pollution in sediments of east coast of Tamilnadu using Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF).

    PubMed

    Ravisankar, R; Sivakumar, S; Chandrasekaran, A; Kanagasabapathy, K V; Prasad, M V R; Satapathy, K K

    2015-08-01

    The study of heavy metal pollution in coastal sediments assumes importance with respect to environmental ecology in view of the rapid industrialization and increased anthropogenic activities. The concentrations of Mg, Al, K, Ca, Ti, Fe, V, Cr, Mn, Co, Ni and Zn were measured in twenty sampling sites along the east coast of Tamilnadu, India by energy dispersive X-ray fluorescence spectroscopy (EDXRF). Natural background values were used to delineate their origin as geogenic or anthropogenic. To interpret and assess the contamination status for heavy metals in sediments, four metal pollution indices used such as an enrichment factor, a geo-accumulation index, a contamination factor and a pollution load index. Multivariate statistical methods were applied to identify the source of heavy metals. Heavy metal toxicity risk was assessed using sediment quality guidelines. The presented methodology was used to determine the anthropogenic origin of heavy metals in the sediment. PMID:25956221

  5. Spatially resolved energy dispersive x-ray spectroscopic method for in-situ evaluation of mechanical properties during the growth of a C - Pt composite nanowire

    SciTech Connect

    Banerjee, Amit; Banerjee, S. S., E-mail: satyajit@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Kanpur, 208016 (India)

    2014-05-15

    A core-shell type C-Pt composite nanowire is fabricated using focused ion and electron beam induced chemical vapor deposition techniques. Using information from spatially resolved energy dispersive x-ray spectra, we detect the resonance vibration in the C-Pt composite nanowire. We use this method to measure the Young's moduli of the constituents (C, Pt) of the composite nanowire and also estimate the density of the FEB CVD grown Pt shell surrounding the C core. By measuring the resonance characteristics of the composite nanowire we estimate a Pt shell growth rate of ?0.9 nms{sup ?1}. The study is analyzed to suggest that the Pt shell growth mechanism is primarily governed by the sticking coefficient of the organometallic vapor on the C nanowire core.

  6. Multi-wavelength study of X-ray luminous clusters at z ~ 0.3. I. Star-formation activity of cluster galaxies

    Microsoft Academic Search

    F. G. Braglia; D. Pierini; A. Biviano; H. Böhringer

    2009-01-01

    Context: The current paradigm of cosmic formation and evolution of galaxy clusters foresees growth mostly through merging. Galaxies in the infall region or in the core of a cluster undergo transformations owing to different environmental stresses. Aims: For two X-ray luminous clusters at redshift z 0.3 with opposite X-ray morphologies (i.e., dynamical states), RXCJ 0014.3-3022 and RXCJ 2308.3-0211, we assess

  7. Rod Packing in Chiral Nematic Cellulose Nanocrystal Dispersions Studied by Small-Angle X-ray Scattering and Laser Diffraction.

    PubMed

    Schütz, Christina; Agthe, Michael; Fall, Andreas B; Gordeyeva, Korneliya; Guccini, Valentina; Salajková, Michaela; Plivelic, Tomás S; Lagerwall, Jan P F; Salazar-Alvarez, German; Bergström, Lennart

    2015-06-16

    The packing of cellulose nanocrystals (CNC) in the anisotropic chiral nematic phase has been investigated over a wide concentration range by small-angle X-ray scattering (SAXS) and laser diffraction. The average separation distance between the CNCs and the average pitch of the chiral nematic phase have been determined over the entire isotropic-anisotropic biphasic region. The average separation distances range from 51 nm, at the onset of the anisotropic phase formation, to 25 nm above 6 vol % (fully liquid crystalline phase) whereas the average pitch varies from ?15 ?m down to ?2 ?m as ? increases from 2.5 up to 6.5 vol %. Using the cholesteric order, we determine that the twist angle between neighboring CNCs increases from about 1° up to 4° as ? increases from 2.5 up to 6.5 vol %. The dependence of the twisting on the volume fraction was related to the increase in the magnitude of the repulsive interactions between the charged rods as the average separation distance decreases. PMID:26020691

  8. 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.

  9. 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.

  10. Millimeter, Microwave, Hard X--ray and Soft X--ray Observations of Energetic Electron Populations in Solar Flares

    E-print Network

    White, Stephen

    Millimeter, Microwave, Hard X--ray and Soft X--ray Observations of Energetic Electron Populations -- 200 keV, microwaves by electrons in the range 100 keV -- 1 MeV, and millimeter--wavelength emission wavelengths are diagnostics of energetic electrons in different energy ranges: soft X--rays are produced

  11. Kinetic Modeling of the X-ray-induced Damage to a Metalloprotein

    PubMed Central

    Davis, Katherine M.; Kosheleva, Irina; Henning, Robert W.; Seidler, Gerald T.; Pushkar, Yulia

    2013-01-01

    It is well known that biological samples undergo x-ray-induced degradation. One of the fastest occurring x-ray-induced processes involves redox modifications (reduction or oxidation) of redox-active cofactors in proteins. Here we analyze room temperature data on the photoreduction of Mn ions in the oxygen evolving complex (OEC) of photosystem II, one of the most radiation damage sensitive proteins and a key constituent of natural photosynthesis in plants, green algae and cyanobacteria. Time-resolved x-ray emission spectroscopy with wavelength-dispersive detection was used to collect data on the progression of x-ray-induced damage. A kinetic model was developed to fit experimental results, and the rate constant for the reduction of OEC MnIII/IV ions by solvated electrons was determined. From this model, the possible kinetics of x-ray-induced damage at variety of experimental conditions, such as different rates of dose deposition as well as different excitation wavelengths, can be inferred. We observed a trend of increasing dosage threshold prior to the onset of x-ray-induced damage with increasing rates of damage deposition. This trend suggests that experimentation with higher rates of dose deposition is beneficial for measurements of biological samples sensitive to radiation damage, particularly at pink beam and x-ray FEL sources. PMID:23815809

  12. Direct rapid analysis of trace bioavailable soil macronutrients by chemometrics-assisted energy dispersive X-ray fluorescence and scattering spectrometry.

    PubMed

    Kaniu, M I; Angeyo, K H; Mwala, A K; Mangala, M J

    2012-06-01

    Precision agriculture depends on the knowledge and management of soil quality (SQ), which calls for affordable, simple and rapid but accurate analysis of bioavailable soil nutrients. Conventional SQ analysis methods are tedious and expensive. We demonstrate the utility of a new chemometrics-assisted energy dispersive X-ray fluorescence and scattering (EDXRFS) spectroscopy method we have developed for direct rapid analysis of trace 'bioavailable' macronutrients (i.e. C, N, Na, Mg, P) in soils. The method exploits, in addition to X-ray fluorescence, the scatter peaks detected from soil pellets to develop a model for SQ analysis. Spectra were acquired from soil samples held in a Teflon holder analyzed using (109)Cd isotope source EDXRF spectrometer for 200 s. Chemometric techniques namely principal component analysis (PCA), partial least squares (PLS) and artificial neural networks (ANNs) were utilized for pattern recognition based on fluorescence and Compton scatter peaks regions, and to develop multivariate quantitative calibration models based on Compton scatter peak respectively. SQ analyses were realized with high CMD (R(2)>0.9) and low SEP (0.01% for N and Na, 0.05% for C, 0.08% for Mg and 1.98 ?g g(-1) for P). Comparison of predicted macronutrients with reference standards using a one-way ANOVA test showed no statistical difference at 95% confidence level. To the best of the authors' knowledge, this is the first time that an XRF method has demonstrated utility in trace analysis of macronutrients in soil or related matrices. PMID:22595429

  13. Imaging with x-ray lasers

    SciTech Connect

    Da Silva, L.B.; Cauble, B.; Frieders, G.; Koch, J.A.; MacGowan, B.J.; Matthews, D.L.; Mrowka, S.; Ress, D.; Trebes, J.E.; Weiland, T.L.

    1993-11-01

    Collisionally pumped soft x-ray lasers now operate over a wavelength range extending from 35--300 {Angstrom}. These sources have high peak brightness and are now being utilized for x-ray imaging and plasma interferometry. In this paper we will describe our efforts to probe long scalelength plasmas using Moire deflectrometry and soft x-ray imaging. The progress in the development of short pulse x-ray lasers using a double pulse irradiation technique which incorporates a travelling wave pump will also be presented.

  14. Portable total reflection x-ray fluorescence analysis in the identification of unknown laboratory hazards

    SciTech Connect

    Liu, Ying, E-mail: liu.ying.48r@st.kyoto-u.ac.jp; Imashuku, Susumu; Sasaki, Nobuharu; Ze, Long; Kawai, Jun [Department of Materials Science and Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Takano, Shotaro; Sohrin, Yoshiki [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Seki, Hiroko; Miyauchi, Hiroya [Kyoto Prefectural Technology Center for Small and Medium Enterprises, Chudojiminami machi, Shimogyo-ku, Kyoto 600-8813 (Japan)

    2014-05-15

    In this study, a portable total reflection x-ray fluorescence (TXRF) spectrometer was used to analyze unknown laboratory hazards that precipitated on exterior surfaces of cooling pipes and fume hood pipes in chemical laboratories. With the aim to examine the accuracy of TXRF analysis for the determination of elemental composition, analytical results were compared with those of wavelength-dispersive x-ray fluorescence spectrometry, scanning electron microscope and energy-dispersive x-ray spectrometry, energy-dispersive x-ray fluorescence spectrometry, inductively coupled plasma atomic emission spectrometry, x-ray diffraction spectrometry (XRD), and x-ray photoelectron spectroscopy (XPS). Detailed comparison of data confirmed that the TXRF method itself was not sufficient to determine all the elements (Z?>?11) contained in the samples. In addition, results suggest that XRD should be combined with XPS in order to accurately determine compound composition. This study demonstrates that at least two analytical methods should be used in order to analyze the composition of unknown real samples.

  15. Optimizing the performance of nickel-like collisionally pumped x-ray lasers. II. Lasers for the wavelength range 50-100Å

    Microsoft Academic Search

    G. J. Pert

    2007-01-01

    Soft x-ray lasers operating in the super- 100Å regime and using grazing incidence pumping methods are now established as efficient sources of radiation in this waveband. The concepts underlying this approach are to separate the ionization and excitation phases of the laser, and to match the pumping density of the latter to the optimal for gain generation. It is therefore

  16. Ultrafast X-ray Sources

    SciTech Connect

    George Neil

    2010-04-19

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

  17. Advances in mercuric iodide energy dispersive x-ray array detectors and associated miniaturized processing electronics (invited)

    NASA Astrophysics Data System (ADS)

    Iwanczyk, J. S.; Dorri, N.; Wang, M.; Szawlowski, M.; Warburton, W. K.; Hedman, B.; Hodgson, K. O.

    1989-07-01

    There are important areas of synchrotron radiation research which would strongly benefit from the availability of energy dispersive detector arrays with high energy resolution and good spatial resolution. The goal of this developmental project is to produce a several element mercuric iodide (HgI2) submodule, which can later be multiplied and grouped into larger arrays of 100-400 elements. A prototype five-element HgI2 array detector was constructed and tested using a synchrotron radiation beam at SSRL. An energy resolution of 280 eV (FWHM) has been obtained for the MnK? line at 5.9 keV. Miniaturized processing electronics were developed in parallel with array advancement. To date, we have completed the hybridized preamplifier and finished breadboarding a computer controlled amplifier. The system integration aspects of large array detectors were studied, producing a conceptual design for both the detector array and its computerized data-acquisition and analysis system.

  18. Soft x-ray polarimeter laboratory tests

    NASA Astrophysics Data System (ADS)

    Murphy, Kendrah D.; Marshall, Herman L.; Schulz, Norbert S.; Jenks, Kevin; Sommer, Sophie J. B.; Marshall, Eric A.

    2010-07-01

    Multilayer-coated optics can strongly polarize X-rays and are central to a new design of a broad-band, soft X-ray polarimeter. We have begun laboratory work to verify the performance of components that could be used in future soft X-ray polarimetric instrumentation. We have reconfigured a 17 meter beamline facility, originally developed for testing transmission gratings for Chandra, to include a polarized X-ray source, an X-ray-dispersing transmission grating, and a multilayer-coated optic that illuminates a CCD detector. The X-rays produced from a Manson Model 5, multi-anode source are polarized by a multilayer-coated flat mirror. The current configuration allows for a 180 degree rotation of the source in order to rotate the direction of polarization. We will present progress in source characterization and system modulation measurements as well as null and robustness tests.

  19. Soft X-ray Polarimetry

    NASA Astrophysics Data System (ADS)

    Marshall, Herman; Schulz, Norbert S.; Heilmann, Ron; Kochanski, Kelly

    2012-09-01

    We developed an instrument design capable of measuring linear X-ray polarization over a broad-band using conventional spectroscopic optics. A set of multilayer-coated flats reflects the dispersed X-rays to the instrument detectors. The intensity variation with position angle is measured to determine three Stokes parameters: I, Q, and U -- all as a function of energy. By laterally grading the multilayer optics and matching the dispersion of the gratings, one may take advantage of high multilayer reflectivities and achieve modulation factors >50% over the entire 0.2 to 0.8 keV band. This instrument could be used in a small orbiting mission or the approach could be used on a large dispersive spectrometric facility. We present progress on laboratory work to demonstrate the capabilities of key components.

  20. Abdominal x-ray

    MedlinePLUS

    Abdominal film; X-ray - abdomen; Flat plate; KUB x-ray ... Diagnose a pain in the abdomen or unexplained nausea Identify suspected problems in the urinary system, such as a kidney stone Identify blockage in the intestine Locate ...

  1. X-Ray Lasers

    ERIC Educational Resources Information Center

    Chapline, George; Wood, Lowell

    1975-01-01

    Outlines the prospects of generating coherent x rays using high-power lasers and indentifies problem areas in their development. Indicates possible applications for coherent x rays in the fields of chemistry, biology, and crystallography. (GS)

  2. In-situ energy dispersive x-ray diffraction study of the growth of CuO nanowires by annealing method

    SciTech Connect

    Srivastava, Himanshu; Ganguli, Tapas; Deb, S. K. [Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced technology, Indore-452013 (India)] [Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced technology, Indore-452013 (India); Sant, Tushar; Poswal, H. K.; Sharma, Surinder M. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai (India)] [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai (India)

    2013-10-14

    The in-situ growth of CuO nanowires was studied by Energy Dispersive X-ray Diffraction (EDXRD) to observe the mechanism of growth. The study was carried out for comparison at two temperatures—at 500 °C, the optimum temperature of the nanowires growth, and at 300 °C just below the temperature range of the growth. The in situ observation revealed the successive oxidation of Cu foil to Cu{sub 2}O layer and finally to CuO layer. Further analysis showed the presence of a compressive stress in CuO layer due to interface at CuO and Cu{sub 2}O layers. The compressive stress was found to increase with the growth of the nanowires at 500 °C while it relaxed with the growth of CuO layer at 300 °C. The present results do not support the existing model of stress relaxation induced growth of nanowires. Based on the detailed Transmission Electron Microscope, Scanning Electron Microscope, and EDXRD results, a microstructure based growth model has been suggested.

  3. Structural analysis of polymer-protected Pd/Pt bimetallic clusters as dispersed catalysts by using extended x-ray absorption fine structure spectroscopy

    SciTech Connect

    Toshima, Naoki; Harada, Masafumi; Yonezawa, Tetsu; Kushihashi, Kakuta; Asakura, Kiyotaka (Univ. of Tokyo (Japan))

    1991-09-19

    Extended X-ray absorption fine structure (EXAFS) was applied to the determination of the structure of colloidal dispersions of the poly (N-vinyl-2-pyrrolidone)-protected palladium/platinum bimetallic clusters, which work as the catalysts for selective partial hydrogenation of 1,3-cyclooctadiene to cyclooctene. The catalytic activity was found to depend on the structure of the bimetallic clusters. The EXAFS data on the Pd/Pt (4/1) bimetallic clusters, which are the most active catalysts, indicate a Pt core structure, in which the 42 Pd atoms are on the surface of the cluster particle and 13 Pt atoms are at the center of the particle, forming a core. In contrast, the Pd/Pt (1/1) bimetallic clusters are suggested to have a modified Pt core structure, in which 28 Pt atoms connect directly with each other, being located both in the core and on the surface, and 27 Pd atoms form three islands on the surface of the cluster particle. These bimetallic clusters work as active catalysts for selective hydrogenation of olefins, selective partial hydrogenation of diene to monoene, and visible light-induced hydrogen generation from water.

  4. Elemental concentration analysis in soil contaminated with recyclable urban garbage by tube-excited energy-dispersive X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Anjos, M. J.; Lopes, R. T.; Jesus, E. F. O.; Assis, J. T.; Cesareo, R.; Barroso, R. C.; Barradas, C. A. A.

    2002-11-01

    Soil and radish (Raphanus Sp) samples from areas treated with organic compost of recyclable urban garbage were quantitatively analyzed by using tube-excited energy-dispersive X-ray fluorescence analysis. Soils treated with 10, 20 and 30 t/ha of recyclable urban garbage and control soil were analyzed. The layer soils were collected at 0-5, 5-10, 10-20, 20-40, 40-60 cm depth. It was possible simultaneously to determine the elemental concentration of various elements: K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Rb, Sr, Zr and Pb in recyclable urban garbage, soil treated with organic compost of recyclable urban garbage and radish plants cultivated in these soils. The elemental concentration of K, Ca, Ti and Fe were determined at percent level (macro-elements) and the other elements at ppm level (micro-elements). It was also possible to observe a significant increase in the contents of K, Ca, Zn, Rb, Sr, Zr and Pb in the soil treated in comparison with the control soil and it was also verified whether the transport of these elements to radish plants cultivated in these soils occurred.

  5. Determination of copper, iron, nickel and zinc in ethanol fuel by energy dispersive X-ray fluorescence after pre-concentration on chromatography paper.

    PubMed

    Teixeira, Leonardo Sena Gomes; Santos, Elenir Souza; Nunes, Luana Sena

    2012-04-13

    This paper presents an alternative analytical method employing energy dispersive X-ray fluorescence (EDXRF) to determine copper, iron, nickel and zinc ions in ethanol fuel samples after a pre-concentration procedure. Our pre-concentration strategy utilizes analyte retention on cation exchange chromatography paper, a convenient substrate for direct EDXRF measurements. The repeatability, expressed in terms of RSD of standard solutions containing 0.25 ?g mL(-1) of Cu, Fe, Ni and Zn, and calculated from fifteen consecutive measurements, was 2.5, 2.8, 3.0, and 2.7%, respectively. The limits of detection (LOD), defined as the analyte concentration that gives a response equivalent to three times the standard deviation of the blank (n=10), were found to be 13, 15, 15 and 12 ?g L(-1) for Cu, Fe, Ni and Zn, respectively. The proposed method was applied to Cu, Fe, Ni and Zn determination in hydrated ethanol fuel samples collected from different gas stations. PMID:22444531

  6. [Chemical composition analysis of early neolithic pottery unearthed from Xiaohuangshang site, Zhejiang Province and Jiahu site, Henan Province by energy disperse X-ray fluorescence].

    PubMed

    Chen, Qian-Qian; Yang, Yu-Zhang; Zhang, Ju-Zhong; Cui, Wei

    2011-11-01

    The major elements in the early neolithic potteries unearthed from Xiaohuangshan site, Zhejiang Province and Jiahu site, Henan Province were determined by energy disperse X-ray fluorescence (EDXRF). The results show that the chemical compositions of the potteries from these two sites possess obvious regional features respectively. Compared with the specimen from Jiahu site, the potteries from Xiaohuangshan site have the common feature of ancient Chinese southern ceramics with high silicon and low aluminum contents. Simultaneously, the chemical composition of Xiaohuangshan pottery samples nearly unchanged from its early stage to the last stage. This phenomenon indicates that the source of the ceramic raw materials of Xiaohuangshan site was stable, and the continuous improvement of its pottery quality was mainly due to the progress in sintering techniques. However, the chemical composition of Jiahu potteries changed a lot in its three different periods. This change occurred because a large number of admixtures were added to the pottery bodies to improve their operating performances. These results also show that the improvements of pottery making techniques in different Chinese areas may have their own evolution directions respectively for the different geographical environments. PMID:22242535

  7. A case of hut lung: scanning electron microscopy with energy dispersive x-ray spectroscopy analysis of a domestically acquired form of pneumoconiosis.

    PubMed

    Mukhopadhyay, Sanjay; Gujral, Manmeet; Abraham, Jerrold L; Scalzetti, Ernest M; Iannuzzi, Michael C

    2013-07-01

    Hut lung is a pneumoconiosis caused by exposure to smoke derived from biomass fuels used for cooking in poorly ventilated huts. We report, to our knowledge, the first analysis of the dust deposited in the lungs in hut lung by scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM/EDS). A Bhutanese woman presented with shortness of breath and an abnormal chest radiograph. Chest CT scan showed innumerable tiny bilateral upper lobe centrilobular nodules. Transbronchial biopsy revealed mild interstitial fibrosis with heavy interstitial deposition of black dust. SEM/EDS showed that the dust was carbonaceous, with smaller yet substantial numbers of silica and silicate particles. Additional history revealed use of a wood/coal-fueled stove in a small, poorly ventilated hut for 45 years. The possibility of hut lung should be considered in women from countries where use of biomass-fueled stoves for cooking is common. Our findings support the classification of this condition as a mixed-dust pneumoconiosis. PMID:23880681

  8. Investigation of Sn surface segregation during GeSn epitaxial growth by Auger electron spectroscopy and energy dispersive x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Tsukamoto, Takahiro; Hirose, Nobumitsu; Kasamatsu, Akifumi; Mimura, Takashi; Matsui, Toshiaki; Suda, Yoshiyuki

    2015-02-01

    The mechanism of Sn surface segregation during the epitaxial growth of GeSn on Si (001) substrates was investigated by Auger electron spectroscopy and energy dispersive X-ray spectroscopy. Sn surface segregation depends on the growth temperature and Sn content of GeSn layers. During Sn surface segregation, Sn-rich nanoparticles form and move on the surface during the deposition, which results in a rough surface owing to facet formation. The Sn-rich nanoparticles moving on the surface during the deposition absorb Sn from the periphery and yield a lower Sn content, not on the surface but within the layer, because the Sn surface segregation and the GeSn deposition occur simultaneously. Sn surface segregation can occur at a lower temperature during the deposition compared with that during postannealing. This suggests that the Sn surface segregation during the deposition is strongly promoted by the migration of deposited Ge and Sn adatoms on the surface originating from the thermal effect of substrate temperature, which also suggests that limiting the migration of deposited Ge and Sn adatoms can reduce the Sn surface segregation and improve the crystallinity of GeSn layers.

  9. X-ray spectropolarimeter

    SciTech Connect

    Baronova, E. O.; Stepanenko, M. M.; Stepanenko, A. M. [RRC Kurchatov Institute, 123182 Moscow (Russian Federation)

    2008-08-15

    We have constructed a novel single-crystal x-ray spectropolarimeter that separates spatially the two perpendicularly polarized components of an x-ray beam. We have tested this device by using an x-ray tube, and confirmed its performance to be satisfactory as expected from its design.

  10. The development of correct methods for Sn-Pb solder analysis by wavelength dispersion X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Gorewoda, Tadeusz; Anyszkiewicz, Jacek; Mzyk, Zofia; Buzek, ?ucja

    2014-02-01

    Soldering is a process of joining metals with an extremely broad range of applications. Among the most popular of the soft alloys are tin-lead solders. The easiest method of soft solder sample preparation for XRF analysis appears to be machining (turning, milling, polishing). Nevertheless, we observed that in the case of the near-eutectic Sn-Pb solder, machining results in smearing of the lead on the sample surface. Our research had also shown the existence of significant structural differences in the crystal structure of samples produced by different producers that prevent proper analysis by XRF spectrometry. To solve the problem of smearing and obtain the smallest and most reproducible microstructures, enabling better measurement averaging, we proposed two simple and fast sample preparation procedures.

  11. Multiple scattering in dispersions, for long wavelength thermoacoustic solutions

    NASA Astrophysics Data System (ADS)

    Hazlehurst, T. A.; Harlen, O. G.; Holmes, M. J.; Povey, M. J. W.

    2014-04-01

    Thermoacoustic scattering is a principal scattering mechanism in the ultrasonic characterisation of water-continuous colloids. Thermal effects are particularly important in highly concentrated systems, where non-propagational thermal fields surrounding the disperse particles overlap. For low concentrations, the single sphere solution of Epstein and Carhart has become a popular tool for determining the particle size distribution. However, for small particle sizes it suffers from ill-conditioning that can make the solution numerically unstable. This problem has been resolved, by Harlen et. al. (2001, SIAM Journal on Applied Mathematics, 61 1906-1931), who obtained an asymptotic solution for low concentrations that is valid when the particle diameter is small compared to the wavelength. In this paper we will use this asymptotic method to calculate the effects of multiple scattering that occur at higher concentrations. We use the addition translation theorem to calculate the effects of multiple scattering between a pair of spheres of different sizes and show how this affects the close-field scattering pattern.

  12. Dispersive liquid-liquid microextraction using diethyldithiocarbamate as a chelating agent and the dried-spot technique for the determination of Fe, Co, Ni, Cu, Zn, Se and Pb by energy-dispersive X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Kocot, Karina; Zawisza, Beata; Sitko, Rafal

    2012-07-01

    Dispersive liquid-liquid microextraction (DLLME) using sodium diethyldithiocarbamate (DDTC) as a chelating agent was investigated for the simultaneous determination of iron, cobalt, nickel, copper, zinc, selenium and lead ions in water samples. The procedure was performed using 5 mL of the sample, 100 ?L of a 0.5% solution of DDTC, 30 ?L of carbon tetrachloride (extraction phase) and 500 ?L of methanol (disperser solvent). The experiments showed that Fe, Co, Ni, Cu, Zn and Pb can be simultaneously extracted at a pH of 5 and that Se can be extracted at a pH of 2-3. The results were compared with those obtained using ammonium pyrrolidine dithiocarbamate as a chelating agent. For all analytes, a linear range was observed up to 0.4 ?g mL- 1. If Fe and Zn are present in concentrations 10 times higher than those of the other analytes, then the linearity is observed up to 0.2 ?g mL- 1. In the present study, the organic phase that contained preconcentrated elements was deposited onto a Millipore filter and measured using energy-dispersive X-ray fluorescence spectrometry. The obtained detection limits were 2.9, 1.5, 2.0, 2.3, 2.5, 2.0 and 3.9 ng mL- 1 for Fe, Co, Ni, Cu, Zn, Se and Pb, respectively. This combination of DLLME and the dried-spot technique is promising for multielement analyses using other spectroscopy techniques, such as laser ablation-inductively coupled plasma-mass spectrometry, laser-induced breakdown spectroscopy or total-reflection X-ray fluorescence spectrometry.

  13. Energy dispersive X-ray fluorescence spectroscopy/Monte Carlo simulation approach for the non-destructive analysis of corrosion patina-bearing alloys in archaeological bronzes: The case of the bowl from the Fareleira 3 site (Vidigueira, South Portugal)

    NASA Astrophysics Data System (ADS)

    Bottaini, C.; Mirão, J.; Figuereido, M.; Candeias, A.; Brunetti, A.; Schiavon, N.

    2015-01-01

    Energy dispersive X-ray fluorescence (EDXRF) is a well-known technique for non-destructive and in situ analysis of archaeological artifacts both in terms of the qualitative and quantitative elemental composition because of its rapidity and non-destructiveness. In this study EDXRF and realistic Monte Carlo simulation using the X-ray Monte Carlo (XRMC) code package have been combined to characterize a Cu-based bowl from the Iron Age burial from Fareleira 3 (Southern Portugal). The artifact displays a multilayered structure made up of three distinct layers: a) alloy substrate; b) green oxidized corrosion patina; and c) brownish carbonate soil-derived crust. To assess the reliability of Monte Carlo simulation in reproducing the composition of the bulk metal of the objects without recurring to potentially damaging patina's and crust's removal, portable EDXRF analysis was performed on cleaned and patina/crust coated areas of the artifact. Patina has been characterized by micro X-ray Diffractometry (?XRD) and Back-Scattered Scanning Electron Microscopy + Energy Dispersive Spectroscopy (BSEM + EDS). Results indicate that the EDXRF/Monte Carlo protocol is well suited when a two-layered model is considered, whereas in areas where the patina + crust surface coating is too thick, X-rays from the alloy substrate are not able to exit the sample.

  14. X-ray absorption in Active Galactic Nuclei

    E-print Network

    R. Maiolino; G. Risaliti

    2007-01-04

    We review some of the main physical and statistical properties of the X-ray absorber in AGNs. In particular, we review the distribution of the absorbing column density inferred from X-ray observations of various AGN samples. We discuss the location of the X-ray absorber and the relation with the dust absorption at optical and infrared wavelengths. Finally, we shortly review the recent findings on X-ray absorption at high luminosities and at high redshift.

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

    E-print Network

    Meagher, Mary

    X-Ray Data Booklet X-RAY DATA BOOKLET Center for X-ray Optics and Advanced Light Source Lawrence Berkeley National Laboratory Introduction X-Ray Properties of Elements Electron Binding Energies X-Ray Levels of Few Electron Ions Now Available Order X-Ray Data Booklet http://xdb.lbl.gov/ (1 of 3) [2

  16. 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.

  17. 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.

  18. The effect of silica on polymorphic precipitation of calcium carbonate: an on-line energy-dispersive X-ray diffraction (EDXRD) study

    NASA Astrophysics Data System (ADS)

    Kellermeier, Matthias; Glaab, Fabian; Klein, Regina; Melero-García, Emilio; Kunz, Werner; García-Ruiz, Juan Manuel

    2013-07-01

    Calcium carbonate is the most abundant biomineral and a compound of great industrial importance. Its precipitation from solution has been studied extensively and was often shown to proceed via distinct intermediate phases, which undergo sequential transformations before eventually yielding the stable crystalline polymorph, calcite. In the present work, we have investigated the crystallisation of calcium carbonate in a time-resolved and non-invasive manner by means of energy-dispersive X-ray diffraction (EDXRD) using synchrotron radiation. In particular, the role of silica as a soluble additive during the crystallisation process was examined. Measurements were carried out at different temperatures (20, 50 and 80 °C) and various silica concentrations. Experiments conducted in the absence of silica reflect the continuous conversion of kinetically formed metastable polymorphs (vaterite and aragonite) to calcite and allow for quantifying the progress of transformation. Addition of silica induced remarkable changes in the temporal evolution of polymorphic fractions existing in the system. Essentially, the formation of calcite was found to be accelerated at 20 °C, whereas marked retardation or complete inhibition of phase transitions was observed at higher temperatures. These findings are explained in terms of a competition between the promotional effect of silica on calcite growth rates and kinetic stabilisation of vaterite and aragonite due to adsorption (or precipitation) of silica on their surfaces, along with temperature-dependent variations of silica condensation rates. Data collected at high silica concentrations indicate the presence of an amorphous phase over extended frames of time, suggesting that initially generated ACC particles are progressively stabilised by silica. Our results may have important implications for CaCO3 precipitation scenarios in both geochemical and industrial settings, where solution silicate is omnipresent, as well as for CO2 sequestration technologies.Calcium carbonate is the most abundant biomineral and a compound of great industrial importance. Its precipitation from solution has been studied extensively and was often shown to proceed via distinct intermediate phases, which undergo sequential transformations before eventually yielding the stable crystalline polymorph, calcite. In the present work, we have investigated the crystallisation of calcium carbonate in a time-resolved and non-invasive manner by means of energy-dispersive X-ray diffraction (EDXRD) using synchrotron radiation. In particular, the role of silica as a soluble additive during the crystallisation process was examined. Measurements were carried out at different temperatures (20, 50 and 80 °C) and various silica concentrations. Experiments conducted in the absence of silica reflect the continuous conversion of kinetically formed metastable polymorphs (vaterite and aragonite) to calcite and allow for quantifying the progress of transformation. Addition of silica induced remarkable changes in the temporal evolution of polymorphic fractions existing in the system. Essentially, the formation of calcite was found to be accelerated at 20 °C, whereas marked retardation or complete inhibition of phase transitions was observed at higher temperatures. These findings are explained in terms of a competition between the promotional effect of silica on calcite growth rates and kinetic stabilisation of vaterite and aragonite due to adsorption (or precipitation) of silica on their surfaces, along with temperature-dependent variations of silica condensation rates. Data collected at high silica concentrations indicate the presence of an amorphous phase over extended frames of time, suggesting that initially generated ACC particles are progressively stabilised by silica. Our results may have important implications for CaCO3 precipitation scenarios in both geochemical and industrial settings, where solution silicate is omnipresent, as well as for CO2 sequestration technologies. Electronic supplementary information (ESI) available: Additiona

  19. Optimal dispersion management for a wavelength division multiplexed optical soliton transmission system

    Microsoft Academic Search

    Hiroto Sugahara; Hiroki Kato; Takashi Inoue; Akihiro Maruta; Yuji Kodama

    1999-01-01

    Soliton's frequency shift arising from the pulse collision between wavelength division multiplexed (WDM) channels in an optical transmission line may be reduced by dispersion management technique. The reduction mechanism is due to a cancellation between the shifts in normal and anomalous dispersion fibers. With a proper management of the dispersion, the effect of lumped amplifiers on the frequency shift may

  20. Energy dispersive X-ray fluorescence and scattering assessment of soil quality via partial least squares and artificial neural networks analytical modeling approaches.

    PubMed

    Kaniu, M I; Angeyo, K H; Mwala, A K; Mwangi, F K

    2012-08-30

    Soil quality assessment (SQA) calls for rapid, simple and affordable but accurate analysis of soil quality indicators (SQIs). Routine methods of soil analysis are tedious and expensive. Energy dispersive X-ray fluorescence and scattering (EDXRFS) spectrometry in conjunction with chemometrics is a potentially powerful method for rapid SQA. In this study, a 25 m Ci (109)Cd isotope source XRF spectrometer was used to realize EDXRFS spectrometry of soils. Glycerol (a simulate of "organic" soil solution) and kaolin (a model clay soil) doped with soil micro (Fe, Cu, Zn) and macro (NO(3)(-), SO(4)(2-), H(2)PO(4)(-)) nutrients were used to train multivariate chemometric calibration models for direct (non-invasive) analysis of SQIs based on partial least squares (PLS) and artificial neural networks (ANN). The techniques were compared for each SQI with respect to speed, robustness, correction ability for matrix effects, and resolution of spectral overlap. The method was then applied to perform direct rapid analysis of SQIs in field soils. A one-way ANOVA test showed no statistical difference at 95% confidence interval between PLS and ANN results compared to reference soil nutrients. PLS was more accurate analyzing C, N, Na, P and Zn (R(2)>0.9) and low SEP of (0.05%, 0.01%, 0.01%, and 1.98 ?g g(-1)respectively), while ANN was better suited for analysis of Mg, Cu and Fe (R(2)>0.9 and SEP of 0.08%, 4.02 ?g g(-1), and 0.88 ?g g(-1) respectively). PMID:22939153

  1. Microbiological or chemical models of enamel secondary caries compared by polarized-light microscopy and energy dispersive X-ray spectroscopy.

    PubMed

    Paradella, Thaís Cachuté; de Sousa, Fernando Augusto Cervantes Garcia; Koga-Ito, Cristiane Yumi; Jorge, Antonio Olavo Cardoso

    2009-08-01

    Different secondary caries models may present different results. The purpose of this study was to compare different in vitro secondary caries models, evaluating the obtained results by polarized-light microscopy (PLM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Standardized human enamel specimens (n = 12) restored with different materials (Z250 conventional composite resin-CRZ, Freedom polyacid-modified composite resin-CRF, Vitremer resin-modified glass-ionomer-GIV, and Fuji IX conventional glass-ionomer cement-GIF) were submitted to microbiological (MM) or chemical caries models (CM). The control group was not submitted to any caries model. For MM, specimens were immersed firstly in sucrose broth inoculated with Streptococcus mutans ATCC 35688, incubated at 37 degrees C/5% CO(2) for 14 days and then in remineralizing solution for 14 days. For CM, specimens were submitted to chemical pH-cycling. Specimens were ground, submitted to PLM and then were dehydrated, gold-sputtered and submitted to SEM and EDS. Results were statistically analyzed by Kruskall-Wallis and Student-Newman-Keuls tests (alpha = 0.05). No differences between in vitro caries models were found. Morphological differences in enamel demineralization were found between composite resin and polyacid-modified composite resin (CRZ and CRF) and between the resin-modified glass-ionomer and the glass-ionomer cement (GIF and GIV). GIF showed higher calcium concentration and less demineralization, differing from the other materials. In conclusion, the glass-ionomer cement showed less caries formation under both in vitro caries models evaluated. PMID:19204918

  2. Chemopreventive effect of vanadium in a rodent model of chemical hepatocarcinogenesis: reflections in oxidative DNA damage, energy-dispersive X-ray fluorescence profile and metallothionein expression.

    PubMed

    Chakraborty, Tridib; Chatterjee, Amrita; Saralaya, Mahesh G; Chatterjee, Malay

    2006-10-01

    In the present study, we investigated the antitumour efficacy of vanadium in a defined rodent model of experimental hepatocarcinogenesis. Hepatic preneoplasia was induced in male Sprague-Dawley rats with a single, necrogenic, intraperitoneal injection of diethylnitrosamine (DEN) (200 mg/kg body weight) followed by promotion with phenobarbital (PB). The levels of modified DNA bases 8-hydroxy-2'-deoxyguanosine (8-OHdG), a potential marker involved in the initiation of carcinogenesis, were measured by high-performance liquid chromatography, whereas tissue trace element status and expression of metallothionein (MT), a Cu-Zn metalloprotein associated with neoplastic cell growth and subsequent development of premalignant phenotype of the cell, were studied by energy-dispersive X-ray fluorescence spectrometry and enzyme-coupled immunohistochemistry, respectively. There was a significant and steady elevation of modified bases (8-OHdG) along with substantial increase in MT immunoexpression and disturbance in trace element homeostasis following DEN exposure. Supplementation of vanadium at a dose of 0.5 ppm for four consecutive weeks strictly abated the formation of 8-OHdG (P < 0.0001; 81.28%) in preneoplastic rat liver. In a long-term DEN plus PB regimen, vanadium was able to limit in situ MT expression with a concomitant decrease in MT immunoreactivity (P < 0.05). Furthermore, vanadium treatment throughout the study restored hepatic levels of essential trace elements and decreased nodular incidence (58.34%) and nodule multiplicity (P < 0.001; 66.89%) in rats treated with DEN plus PB. Taken together, the study provides evidence in support of the chemopreventive potential of vanadium in limiting neoplastic transformation during the preneoplastic stages of hepatocarcinogenesis in rats. PMID:16830150

  3. Quantitative Measurements of X-ray Intensity

    SciTech Connect

    Haugh, M. J., Schneider, M.

    2011-09-01

    This chapter describes the characterization of several X-ray sources and their use in calibrating different types of X-ray cameras at National Security Technologies, LLC (NSTec). The cameras are employed in experimental plasma studies at Lawrence Livermore National Laboratory (LLNL), including the National Ignition Facility (NIF). The sources provide X-rays in the energy range from several hundred eV to 110 keV. The key to this effort is measuring the X-ray beam intensity accurately and traceable to international standards. This is accomplished using photodiodes of several types that are calibrated using radioactive sources and a synchrotron source using methods and materials that are traceable to the U.S. National Institute of Standards and Technology (NIST). The accreditation procedures are described. The chapter begins with an introduction to the fundamental concepts of X-ray physics. The types of X-ray sources that are used for device calibration are described. The next section describes the photodiode types that are used for measuring X-ray intensity: power measuring photodiodes, energy dispersive photodiodes, and cameras comprising photodiodes as pixel elements. Following their description, the methods used to calibrate the primary detectors, the power measuring photodiodes and the energy dispersive photodiodes, as well as the method used to get traceability to international standards are described. The X-ray source beams can then be measured using the primary detectors. The final section then describes the use of the calibrated X-ray beams to calibrate X-ray cameras. Many of the references are web sites that provide databases, explanations of the data and how it was generated, and data calculations for specific cases. Several general reference books related to the major topics are included. Papers expanding some subjects are cited.

  4. CLASSICAL AREAS OF PHENOMENOLOGY: Zero dispersion wavelength and dispersion slope control of hollow-core photonic bandgap fibres

    NASA Astrophysics Data System (ADS)

    Zhang, Hu; Yang, Bo-Jun; Liu, Yu-Min; Wang, Qiu-Guo; Yu, Li; Zhang, Xiao-Guang

    2009-03-01

    This paper investigates the zero dispersion wavelength and dispersion slope control of hollow-core photonic bandgap fibres (PBGFs) by using a full-vector finite element method. By simulation we found that theoretically the zero dispersion wavelength can be tailored by respectively changing the rounded diameter of air holes, pitch, refractive index, normalized thickness of core rings, and hole diameter to pitch ratio. At the same time the tailoring of dispersion slope can also be realized by changing the rounded diameter of air holes or pitch or normalized thickness of core rings. To illustrate the reasonability of fibre designs, this paper also gives the variance of normalized interface field intensity which measures the scattering loss relatively versus wavelength for different designs. From the viewpoint of loss, varying the rounded diameter and the thickness of core ring could shift zero wavelength but it is difficult to get the required parameters within so tiny range in practical drawing of PBGFs, on the other hand, it is possible in practice to respectively alter the pitch and refractive index to shift zero wavelength. But varying hole diameter to pitch ratio is not worthwhile because they each induce large increase of loss and narrowness of transmission bandwidth. The zero dispersion wavelength can be engineered by respectively varying the rounded diameter of air holes, pitch, refractive index, and normalized thickness of core rings without incurring large loss penalties.

  5. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  6. X-ray imager

    Microsoft Academic Search

    Grachik H. Avetisyan; Alexej K. Erkin; Vladimir B. Kulikov; Vitalij P. Kotov; Yuri A. Kuznetsov; Vladimir M. Trubnikov

    1997-01-01

    The paper presents the findings of an investigation into some characteristics of an X-ray imager. The imager is an assembly of modules, each incorporating a linear array of GaAs detectors connected electrically to a CCD multiplexer. The X-ray imager can be used in industrial and medical X-ray diagnostic equipment. Bibtex entry for this abstract Preferred format for this abstract (see

  7. Fundamental physics with an X-ray free electron laser

    Microsoft Academic Search

    T. Tajima

    2003-01-01

    Of late, laboratories around the world are considering building X-ray free electron lasers based on high energy electron accelerators\\u000a (with energies exceeding 10 GeV) to produce bright coherent X rays with wavelengths on the order of 1 . Because of the extremely\\u000a small wavelength and high brilliance of these coherent X rays, there is an unprecedented opportunity to explore new

  8. Lacquer polishing of X-ray optics

    NASA Technical Reports Server (NTRS)

    Catura, R. C.; Joki, E. G.; Roethig, D. T.; Brookover, W. J.

    1987-01-01

    Techniques for polishing figured X-ray optics by a lacquer-coating process are described. This acrylic lacquer coating has been applied with an optical quality of an eighth-wave in red light and very effectively covers surface roughness with spatial wavelengths less than about 0.2 mm. Tungsten films have been deposited on the lacquer coatings to provide highly efficient X-ray reflectivity.

  9. X-ray transfer

    SciTech Connect

    Castor, J.I.

    1992-03-01

    The computational techniques for treating radiative transfer in general, and x-ray transfer in particular, are reviewed, with emphasis on the difficult problems associated with systems that are not in local thermodynamic equilibrium. Some special aspects of x-ray transfer are mentioned. The computer code ALTAIR, developed at LLNL to solve such problems, is described briefly, with an example of x-ray fluorescence in a Seyfert galaxy. Some of the prospects for experimental tests of x-ray radiative transfer theory are considered.

  10. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Precision measurements of wavelengths of x-ray spectral lines of multiply charged ions in a recombining laser plasma

    NASA Astrophysics Data System (ADS)

    Bryunetkin, B. A.; Pikuz, S. A.; Skobelev, I. Yu; Faenov, A. Ya; Khabibulaev, B. K.; Érmatov, Sh A.

    1992-09-01

    A method of improving the accuracy of measurements of the wavelengths of spectral lines of multiply charged ions was proposed and implemented experimentally. The method involved recording the emission spectra of a recombining laser plasma. Wavelengths of various lines of F VIII and F IX ions were measured with a relative error ?? / ? approx (6-8) × 10-5.

  11. High-intensity double-pulse X-ray free-electron laser.

    PubMed

    Marinelli, A; Ratner, D; Lutman, A A; Turner, J; Welch, J; Decker, F-J; Loos, H; Behrens, C; Gilevich, S; Miahnahri, A A; Vetter, S; Maxwell, T J; Ding, Y; Coffee, R; Wakatsuki, S; Huang, Z

    2015-01-01

    The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitude in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion. PMID:25744344

  12. High-intensity double-pulse X-ray free-electron laser

    PubMed Central

    Marinelli, A.; Ratner, D.; Lutman, A. A.; Turner, J.; Welch, J.; Decker, F.-J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A. A.; Vetter, S.; Maxwell, T.J.; Ding, Y.; Coffee, R.; Wakatsuki, S.; Huang, Z.

    2015-01-01

    The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitude in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion. PMID:25744344

  13. High-intensity double-pulse X-ray free-electron laser

    DOE PAGESBeta

    Marinelli, A.; Ratner, D.; Lutman, A.A.; Turner, J.; Welch, J.; Decker, F.-J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A.A.; et al

    2015-03-06

    The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitudemore »in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion.« less

  14. High-intensity double-pulse X-ray free-electron laser

    NASA Astrophysics Data System (ADS)

    Marinelli, A.; Ratner, D.; Lutman, A. A.; Turner, J.; Welch, J.; Decker, F.-J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A. A.; Vetter, S.; Maxwell, T. J.; Ding, Y.; Coffee, R.; Wakatsuki, S.; Huang, Z.

    2015-03-01

    The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitude in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion.

  15. X-Rays

    MedlinePLUS

    ... are a type of radiation called electromagnetic waves. X-ray imaging creates pictures of the inside of your body. The images show the parts of your body in different shades of black and white. ... Calcium in bones absorbs x-rays the most, so bones look white. Fat and ...

  16. X-ray

    MedlinePLUS

    ... Most experts feel that the benefits of appropriate x-ray imaging greatly outweigh any risks. Young children and babies in the womb are more sensitive to the risks of x-rays. Tell your health care provider if you think ...

  17. X-Rays

    MedlinePLUS

    ... without detail on a dental X-ray, but teeth show up much lighter. Restorations such as crowns and fillings are even denser than bone. They show up as solid, bright white areas on X-rays. Dental decay and caries (cavities) appear as darker patches. ...

  18. X-Ray Waveguides

    NASA Astrophysics Data System (ADS)

    Bukreev, Ianna; Cedola, Alessia; Pellicia, Daniele; Jark, Werner; Lagomarsino, Stefano

    2013-01-01

    This chapter deals with the fundamental properties of X-ray waveguides (WGs), whose development is a logical consequence of the theoretical and experimental work on X-ray standing waves. The different coupling modes and the formation of the wavefield inside the WG are reviewed. Some fabrication procedures and relevant applications are also briefly described.

  19. X-ray binaries

    Microsoft Academic Search

    H. Schatz; K. E. Rehm

    2006-01-01

    We review the nuclear astrophysics aspects of accreting neutron stars in\\u000aX-ray binaries. We summarize open astrophysical questions in light of recent\\u000aobservations and their relation to the underlying nuclear physics. Recent\\u000aprogress in the understanding of the nuclear physics, especially of X-ray\\u000abursts, is also discussed.

  20. Detection of x ray sources in PROS

    NASA Technical Reports Server (NTRS)

    Deponte, J.; Primini, F. A.

    1992-01-01

    The problem of detecting discrete sources in x-ray images has much in common with the problem of automatic source detection at other wavelengths. In all cases, one searches for positive brightness enhancements exceeding a certain threshold, which appear consistent with what one expects for a point source, in the presence of a (possibly) spatially variable background. Multidimensional point spread functions (e.g., dependent on detector position and photon energy) are also common. At the same time, the problem in x-ray astronomy has some unique aspects. For example, for typical x-ray exposures in current or recent observatories, the number of available pixels far exceeds the number of actual x-ray events, so Poisson, rather than Gaussian statistics apply. Further, extended cosmic x-ray sources are common, and one often desires to detect point sources in the vicinity or even within bright, diffuse x-ray emission. Finally, support structures in x-ray detectors often cast sharp shadows in x-ray images making it necessary to detect sources in a region of rapidly varying exposure. We have developed a source detection package within the IRAF/PROS environment which attempts to deal with some of the problems of x-ray source detection. We have patterned our package after the successful Einstein Observatory x-ray source detection programs. However, we have attempted to improve the flexibility and accessibility of the functions and to provide a graphical front-end for the user. Our philosophy has been to use standard IRAF tasks whenever possible for image manipulation and to separate general functions from mission-specific ones. We will report on the current status of the package and discuss future developments, including simulation tasks, to allow the user to assess detection efficiency and source significance, tasks to determine source intensity, and alternative detection algorithms.

  1. Method for the determination of Pd-catalyst residues in active pharmaceutical ingredients by means of high-energy polarized-beam energy dispersive X-ray fluorescence.

    PubMed

    Marguí, E; Van Meel, K; Van Grieken, R; Buendía, A; Fontàs, C; Hidalgo, M; Queralt, I

    2009-02-15

    In medicinal chemistry, Pd is perhaps the most-widely utilized precious metal, as catalyst in reactions which represent key transformations toward the synthesis of new active pharmaceutical ingredients (APIs). The disadvantage of this metal-catalyzed chemistry is that expensive and toxic metal residues are invariably left bound to the desired product. Thus, stringent regulatory guidelines exist for the amount of residual Pd that a drug candidate is allowed to contain. In this work, a rapid and simple method for the determination of Pd in API samples by high-energy polarized-beam energy dispersive X-ray fluorescence spectrometry has been developed and validated according to the specification limits of current legislation (10 mg kg(-1) Pd) and the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH guidelines). Sample and calibration standards preparation includes a first step of homogenization and then, in a second step, the pressing of the powdered material into pellets without any chemical treatment. The use of several synthetic calibration standards made of cellulose to simulate the API matrix appears to be an effective means to obtain reliable calibration curves with a good spread of data points over the working range. With the use of the best measuring conditions, the limit of detection (0.11 mg kg(-1) Pd) as well as the limit of quantitation (0.37 mg kg(-1) Pd) achieved meet rigorous requirements. The repeatability of the XRF measurement appeared to be less than 2%, while the precision of the whole method was around 7%. Trueness was evaluated by analyzing spiked API samples at the level of the specification limit and calculating the recovery factor, which was better than 95%. To study the applicability of the developed methodology for the intended purpose, three batches of the studied API were analyzed for their Pd content, and the attained results were comparable to those obtained by the daily routine method (acid digestion plus atomic spectroscopy) used in most pharmaceutical laboratories. PMID:19161258

  2. Multi-wavelength study of X-ray luminous clusters at z ~ 0.3. I. Star-formation activity of cluster galaxies

    NASA Astrophysics Data System (ADS)

    Braglia, F. G.; Pierini, D.; Biviano, A.; Böhringer, H.

    2009-06-01

    Context: The current paradigm of cosmic formation and evolution of galaxy clusters foresees growth mostly through merging. Galaxies in the infall region or in the core of a cluster undergo transformations owing to different environmental stresses. Aims: For two X-ray luminous clusters at redshift z 0.3 with opposite X-ray morphologies (i.e., dynamical states), RXCJ 0014.3-3022 and RXCJ 2308.3-0211, we assess differences in galaxy populations as a function of cluster topography. This is a pilot study for the joint X-ray and optical analysis of the REFLEX-DXL cluster sample. Methods: Cluster large-scale structure and substructure are determined from the combined photometry in the B, V, and R bands, and from multi-object optical spectroscopy at low resolution. Photometric redshifts and broad-band optical colours are determined. A spectral index analysis is performed, based on the [O II](??3726, 3728 Å) and H?(?4102 Å) features, and the D4000 break, which are available for more than 100 member galaxies per cluster. Additional far-ultraviolet (FUV) photometry is retrieved from the GALEX archive. Combination of spectral indices and FUV-optical colours provides a picture of the star-formation history in galaxies. Results: In spite of the potential presence of a small fraction of galaxies with obscured star-formation activity, the average star-formation history of cluster members is found to depend on clustercentric distance and, more interestingly, on cluster substructure. The core regions of both clusters mainly host galaxies dominated by old, passively evolving stellar populations, which define the same red sequence in a (B-R) colour-R magnitude diagram. However, a sharp increase in star-formation activity is found along two clearly evident filamentary structures of the merging cluster RXCJ 0014.3-3022, out to its virial radius and beyond. It is produced by luminous (i.e., LR ? LRstar) and sub-Lstar galaxies. In contrast, the regular cool-core cluster RXCJ 2308.3-0211 mostly hosts galaxies that either populate the red sequence or are becoming more passive. This finding holds out to the cluster virial radius, and also for its immediate large-scale environment. Conclusions: These results suggest the existence of a correspondence between assembly state and overall age of the stellar populations of galaxies inside the virialized region and in the surrounding large-scale structure of massive clusters at z 0.3. Tables 9 and 10 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/500/947

  3. Chemometric classification of gunshot residues based on energy dispersive X-ray microanalysis and inductively coupled plasma analysis with mass-spectrometric detection

    Microsoft Academic Search

    S. Steffen; M. Otto; L. Niewoehner; M. Barth; J. Biegstraaten; R. Horváth

    2007-01-01

    A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups:

  4. Tunable WDM dispersion compensation with fixed bandwidth and fixed passband center wavelength using a uniform FBG

    Microsoft Academic Search

    Y. W. Song; D. Starodubov; Z. Pan; Y. Xie; A. E. Willner; J. Feinberg

    2002-01-01

    We report an fiber Bragg grating-based tunable dispersion compensator with fixed bandwidth and fixed passband center wavelength for wavelength-division-multiplexing (WDM) channels. Chirping of the grating is achieved by bending a cantilever, and the tunability is realized by controlling the length of the induced chirping within a longer uniform grating. Due to the fixed center wavelength and bandwidth, crosstalk from adjacent

  5. [Development of X-ray excited fluorescence spectrometer].

    PubMed

    Ni, Chen; Gu, Mu; Di, Wang; Cao, Dun-Hua; Liu, Xiao-Lin; Huang, Shi-Ming

    2009-08-01

    An X-ray excited fluorescence spectrometer was developed with an X-ray tube and a spectrometer. The X-ray tube, spectrometer, autocontrol method and data processing selected were roundly evaluated. The wavelength and detecting efficiency of the apparatus were calibrated with the mercury and tungsten bromine standard lamps, and the X-ray excited emission spectra of BaF2, Cs I (Tl) crystals were measured. The results indicate that the apparatus has advantages of good wavelength resolution, high stability, easy to operation and good radioprotection. It is a wery effective tool for exploration of new scintillation materials. PMID:19839360

  6. Normal incidence x-ray mirror for chemical microanalysis

    DOEpatents

    Carr, M.J.; Romig, A.D. Jr.

    1987-08-05

    An x-ray mirror for both electron column instruments and micro x-ray fluorescence instruments for making chemical, microanalysis comprises a non-planar mirror having, for example, a spherical reflecting surface for x-rays comprised of a predetermined number of alternating layers of high atomic number material and low atomic number material contiguously formed on a substrate and whose layers have a thickness which is a multiple of the wavelength being reflected. For electron column instruments, the wavelengths of interest lie above 1.5nm, while for x-ray fluorescence instruments, the range of interest is below 0.2nm. 4 figs.

  7. Coherent x-ray lasers for applications

    SciTech Connect

    London, R.A.; Amendt, P.; Rosen, M.D.; Feit, M.D.; Fleck, J.A. (Lawrence Livermore National Lab., CA (USA)); Strauss, M. (Negev Nuclear Research Centre, Beersheba (Israel))

    1990-12-01

    Many of the projected applications of x-ray lasers require high quality output radiation with properties such as short wavelength, high power, good focusability, short pulse, and high degree of coherence. We discuss the requirements of an x-ray laser for the application of holography of biological samples. We present ideas for achieving these properties. Given that population inversions can be established to provide laser gain, we discuss how the propagation and amplification of x-rays within the lasing medium affect the quality of the output radiation. Particular attention is given toward the development of transverse coherence. Results are presented from several methods for calculating the coherence, including a modal analysis and a numerical-wave propagation code. Calculations of the expected degree of coherence of standard x-ray lasers are given, as well as designs for more coherent lasers. 9 refs., 6 figs., 1 tab.

  8. Massively parallel X-ray holography

    NASA Astrophysics Data System (ADS)

    Marchesini, Stefano; Boutet, Sébastien; Sakdinawat, Anne E.; Bogan, Michael J.; Bajt, Saša; Barty, Anton; Chapman, Henry N.; Frank, Matthias; Hau-Riege, Stefan P.; Szöke, Abraham; Cui, Congwu; Shapiro, David A.; Howells, Malcolm R.; Spence, John C. H.; Shaevitz, Joshua W.; Lee, Joanna Y.; Hajdu, Janos; Seibert, Marvin M.

    2008-09-01

    Advances in the development of free-electron lasers offer the realistic prospect of nanoscale imaging on the timescale of atomic motions. We identify X-ray Fourier-transform holography as a promising but, so far, inefficient scheme to do this. We show that a uniformly redundant array placed next to the sample, multiplies the efficiency of X-ray Fourier transform holography by more than three orders of magnitude, approaching that of a perfect lens, and provides holographic images with both amplitude- and phase-contrast information. The experiments reported here demonstrate this concept by imaging a nano-fabricated object at a synchrotron source, and a bacterial cell with a soft-X-ray free-electron laser, where illumination by a single 15-fs pulse was successfully used in producing the holographic image. As X-ray lasers move to shorter wavelengths we expect to obtain higher spatial resolution ultrafast movies of transient states of matter.

  9. X-Ray Background Survey Spectrometer (XBSS)

    NASA Technical Reports Server (NTRS)

    Sanders, W. T. (Principal Investigator); Paulos, R. J.

    1996-01-01

    The objective of this investigation was to perform a spectral survey of the low energy diffuse X-ray background using the X-ray Background Survey Spectrometer (XBSS) on board the Space Station Freedom (SSF). XBSS obtains spectra of the X-ray diffuse background in the 11-24 A and 44-84 A wavelength intervals over the entire sky with 15 deg spatial resolution. These X-rays are almost certainly from a very hot (10(exp 6) K) component of the interstellar medium that is contained in regions occupying a large fraction of the interstellar volume near the Sun. Astrophysical plasmas near 10(exp 6) K are rich in emission lines, and the relative strengths of these lines, besides providing information about the physical conditions of the emitting gas, also provide information about its history and heating mechanisms.

  10. Optimizing the performance of nickel-like collisionally pumped x-ray lasers. III. Exploding foil lasers for the wavelength range below 50 A ring

    Microsoft Academic Search

    Pert

    2007-01-01

    In previous work, it was found that heat conduction limited the development of laser action at wavelengths below 50 A ring . In this paper, we discuss the use of thin foils to limit these effects, and generate a high-density and -temperature plasma with low refractive index gradient. By using a relatively short (100 ps) first pulse and short (1

  11. Programmed cell death: Cytochemical and X-ray microanalytical characterization of calcium compartments in neuromuscular junctions during the normal breakdown of the intersegmental muscles in the giant silkmoth Antheraea polyphemus

    Microsoft Academic Search

    Jacques Beaulaton; Universitd Blaise

    1988-01-01

    Summary  Calcium stores were cytochemically demonstrated using a combined oxalate—pyroantimonate method in the neuromuscular junctions of the degenerating intersegmental muscles in the giant silkmothAntheraea polyphemus. The elemental composition of punctate precipitates of the reaction product was determined by electron probe X-ray microanalysis of unstained thin sections by energy-dispersive spectrometry and wavelength-dispersive spectrometry. The wavelength-dispersive spectra collected over terminal axons demonstrate a

  12. X-ray laser

    DOEpatents

    Nilsen, Joseph (Livermore, CA)

    1991-01-01

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

  13. Panoramic Dental X-Ray

    MedlinePLUS

    ... x-rays. top of page What does the equipment look like? A panoramic x-ray machine consists ... current x-ray images for diagnosis and disease management. The digital format also allows the dentist to ...

  14. The X-ray universe

    NASA Astrophysics Data System (ADS)

    Tucker, Wallace; Giacconi, Riccardo

    This book is a selective and personal history of X-ray astronomy. The X-ray universe is considered along with the sensible world, historical aspects regarding the discovery and utilization of X-rays, the pioneers of X-ray astronomy, the discovery of an X-ray star, the riddle of the X-ray stars, developments leading to the Uhuru (X-ray Explorer) satellite and the study of neutron stars and black holes, the X-ray sky, a telescope for X-rays, the Einstein observatory (HEAO-2), stellar coronas and supernovas, active galaxies and quasars, clusters of galaxies and the missing mass, and the cosmic X-ray background. Attention is also given to NASA's Advanced X-Ray Astrophysics Facility, which will open a permanent window on the X-ray universe.

  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. Spectra of cosmic X-ray sources

    NASA Technical Reports Server (NTRS)

    Holt, S. S.; Mccray, R.

    1982-01-01

    X-ray measurements provide the most direct probes of astrophysical environments with temperatures exceeding one million K. Progress in experimental research utilizing dispersive techniques (e.g., Bragg and grating spectroscopy) is considerably slower than that in areas utilizing photometric techniques, because of the relative inefficiency of the former for the weak X-ray signals from celestial sources. As a result, the term "spectroscopy" as applied to X-ray astronomy has traditionally satisfied a much less restrictive definition (in terms of resolving power) than it has in other wavebands. Until quite recently, resolving powers of order unity were perfectly respectable, and still provide (in most cases) the most useful spectroscopic data. In the broadest sense, X-ray photometric measurements are spectroscopic, insofar as they represent samples of the overall electromagnetic continua of celestial objects.

  17. Optimizing the performance of nickel-like collisionally pumped x-ray lasers. III. Exploding foil lasers for the wavelength range below 50 A ring

    SciTech Connect

    Pert, G. J. [Physics Department, University of York, Heslington, York, YO10 5DD (United Kingdom)

    2007-06-15

    In previous work, it was found that heat conduction limited the development of laser action at wavelengths below 50 A ring . In this paper, we discuss the use of thin foils to limit these effects, and generate a high-density and -temperature plasma with low refractive index gradient. By using a relatively short ({approx}100 ps) first pulse and short ({approx}1 ps) second, it is shown that effective high-gain systems may be developed.

  18. X rays in medicine

    SciTech Connect

    Hendee, W.R. [Medical College of Wisconsin, Milwaukee, Wisconsin (United States)

    1995-11-01

    For almost a century, x rays have been used for medical imaging and for radiation therapy. Now these two clinical regimes are converging in the latest technology. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}.

  19. X-Ray Diffraction.

    ERIC Educational Resources Information Center

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  20. X-Ray Diffraction

    NSDL National Science Digital Library

    Matter.org

    This site from the University of London presents a tutorial on several methods of X-ray diffraction, including the powder, rotating crystal, and Laue methods Each section includes interactive Java applets, exercises, and links to a glossary of terms.

  1. Application of energy-dispersive X-ray elemental mapping to probe the homogeneity of sol-gel derived YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} and related phases

    SciTech Connect

    Houk, C.S.; Burgoine, G.A.; Page, C.J. [Univ. of Oregon, Eugene, OR (United States)

    1995-04-01

    The authors describe results obtained using energy dispersive X-ray (EDX) elemental mapping to probe the homogeneity of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. Sol-gel synthesis and conventional solid-state synthesis of the ceramic with firing to 950{degrees}C and sol-gel synthesis with firing at 700{degrees}C are the synthetic routes considered. It was found that the low temperature sol-gel method yields high-quality YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} provided the firing stage is of sufficient duration.

  2. Simultaneous determination of trace elements in lavage fluids from human bronchial alveoli by energy-dispersive x-ray fluorescence. 2: Determination of abnormal lavage contents and verification of the results

    SciTech Connect

    Maier, E.A.; Dietemann-Molard, A.; Rastegar, F.; Heimburger, R.; Ruch, C.; Maier, A.; Roegel, E.; Leroy, M.J.

    1986-04-01

    We applied energy-dispersive x-ray fluorescence to the determination of abnormally present elements or abnormal concentrations of elements in human broncho-alveolar lavage fluids. The low detection limits and the ability to perform multi-elemental analysis permit one to establish or confirm occupational exposure of workers. We also describe different methods used to check our method and our results. We report examples of abnormal compositions of broncho-alveolar lavages containing W, Ce, La, Nd, I, Fe, or Ni. We discuss the limits of the method for characterizing silicosis or asbestosis.

  3. Application of x-ray phase plate to grazing incidence x-ray topography for the control of penetration depth

    NASA Astrophysics Data System (ADS)

    Hirano, Keiichi; Takahashi, Yumiko; Nagamachi, Shinji

    2013-11-01

    The penetration depth of x-rays into a crystal is one of the most important parameters in grazing incidence x-ray topography. In this paper, we introduce a novel method for controlling the penetration depth by modifying the polarization of incident x-rays with fixed sample geometry and x-ray wavelength. We employed an x-ray phase plate in transmission geometry for controlling the polarization, and obtained x-ray topographs of an ion-implanted 4H-SiC epitaxial wafer with ?- and ?-polarized x-rays. By comparing the two topographs, it was verified that the penetration depth of ?-polarization is smaller than that of ?-polarization.

  4. Study of the X-ray microbeam for scanning microscopes

    Microsoft Academic Search

    Y. Iketaki; Y. Horikawa; S. Mochimaru; K. Nagai; T. Kiyokura; M. Oshima; A. Yagishita

    1996-01-01

    We fabricated a Schwarzschild X-ray objective which has the maximum X-ray transmittance of 9% at the wavelength of 14.1nm and evaluated an X-ray microbeam formed by the objective. We measured the knife-edge response of the microbeam and performed a fitting calculation of the response, using the point-spread function for the objective. It was found that the beam diameter of the

  5. Review of soft x-ray laser researches and developments

    Microsoft Academic Search

    Hiroyuki Daido

    2002-01-01

    In this paper, the author reviews the plasma-based x-ray lasers which we have already demonstrated saturated amplification whose wavelengths are between 50 and 6 nm.Section 1 describes the motivation of this review paper which includes basic ideas, developments and their applications of x-ray lasers. In section 2, the author describes the early x-ray laser researches on the recombination and the

  6. SCATTERING BY INTERSTELLAR DUST GRAINS. II. X-RAYS B. T. Draine

    E-print Network

    Draine, Bruce T.

    2001, 2002), scattered light at optical and ultraviolet wavelengths (Draine 2003b), and the X-ray scat. The angular distri- bution of the scattered X-rays is discussed; the median scat- tering angle s;50 is found

  7. X-ray laser driven gold targets

    NASA Astrophysics Data System (ADS)

    Petrova, Tz. B.; Whitney, K. G.; Davis, J.

    2014-03-01

    The femtosecond population dynamics of gold irradiated by a coherent high-intensity (>1017 W/cm2) x-ray laser pulse is investigated theoretically. There are two aspects to the assembled model. One is the construction of a detailed model of platinum-like gold inclusive of all inner-shell states that are created by photoionization of atomic gold and decay either by radiative or Auger processes. Second is the computation of the population dynamics that ensues when an x-ray pulse is absorbed in gold. The hole state generation depends on the intensity and wavelength of the driving x-ray pulse. The excited state populations reached during a few femtosecond timescales are high enough to generate population inversions, whose gain coefficients are calculated. These amplified lines in the emitted x-ray spectrum provide important diagnostics of the radiation dynamics and also suggest a nonlinear way to increase the frequency of the coherent output x-ray pulses relative to the frequency of the driver input x-ray pulse.

  8. Spectroscopic Studies in X-ray Astronomy

    NASA Astrophysics Data System (ADS)

    Choi, Chul-Sung

    2000-09-01

    X-ray astronomy deals with measurements of the electromagnetic radiation in the energy range of E 0.1- 100 keV. The wavelength of X-ray is comparable to the size of atoms, so that the photons in the X-ray range are usually produced and absorbed by the atomic processes. Since the launch of the first X-ray astronomy satellite "Uhuru" in 1970, technological advances in a launch capability and a detection capability make X-ray astronomy one of the most rapidly evolving fields of astronomical research. Particularly, a spectral resolving power E/Delta E has been increased by an order of 2 - 3 (in the energy range of 0,1 - 10 keV) during the past 30 years. In this paper, I briefly review a developing process of the resolving power and spectroscopic techniques. Then I describe important emission/absorption lines in X-ray astronomy, as well as diagnostics of gas property with line parameters.

  9. X-ray modulation transfer functions of photostimulable phosphor image plates and scanners

    SciTech Connect

    Seely, John F.; Holland, Glenn E.; Hudson, Lawrence T.; Henins, Albert

    2008-11-01

    The modulation transfer functions of two types of photostimulable phosphor image plates were determined in the 10 keV to 50 keV x-ray energy range using a resolution test pattern with up to 10 line pairs per mm (LP/mm) and a wavelength dispersive x-ray spectrometer. Techniques were developed for correcting for the partial transmittance of the high energy x rays through the lead bars of the resolution test pattern, and the modulation transfer function (MTF) was determined from the measured change in contrast with LP/mm values. The MTF was convolved with the slit function of the image plate scanner, and the resulting point spread functions (PSFs) were in good agreement with the observed shapes and widths of x-ray spectral lines and with the PSF derived from edge spread functions. The shapes and the full width at half-maximum (FWHM) values of the PSF curves of the Fuji Superior Resolution (SR) and Fuji Maximum Sensitivity (MS) image plate detectors, consisting of the image plate and the scanner, determined by the three methods gave consistent results: The SR PSF is Gaussian with 0.13 mm FWHM, and the MS PSF is Lorentzian with 0.19 mm FWHM. These techniques result in the accurate determination of the spatial resolution achievable using image plate and scanner combinations and enable the optimization of spatial resolution for x-ray spectroscopy and radiography.

  10. Lumbosacral spine x-ray

    MedlinePLUS

    X-ray - lumbosacral spine; X-ray - lower spine ... be placed over the lower part of your spine. You will be asked to hold your breath ... x-ray. The most common reason for lumbosacral spine x-ray is to look for the cause ...

  11. Improvements to the accuracy of the IUE wavelength scales in high dispersion

    NASA Astrophysics Data System (ADS)

    Turnrose, B. E.; Harvel, C. A.; Bohlin, R. C.

    The data base of Pt-Ne emission lines used to calibrate the IUE high dispersion wavelength scales was scrutinized to improve the internal consistency of the adopted laboratory wavelength values and provide a homogeneous, documented line list, which IUE Guest Observers may use to evaluate quantitatively those Pt-Ne spectra taken to calibrate their data. After deletion of incorrect or inappropriate data in the old data base (lines with incorrect wavelength assignments; lines which are too faint, too bright, or blended; lines which fall near reseau marks, etc.) and the addition of several new entries, a total of 172 Pt-Ne lines for the SWP camera and 164 Pt-Ne lines for the LWR camera are now used for routine wavelength calibration in the high dispersion mode.

  12. ASTRO-H Soft X-ray Telescope (SXT)

    Microsoft Academic Search

    Yang Soong; Peter J. Serlemitsos; Takashi Okajima; Devin Hahne

    2011-01-01

    ASTRO-H is an astrophysics satellite dedicated for X-ray spectroscopic study non-dispersively and to carry out survey complementally, which will be borne out of US-Japanese collaborative effort. Among the onboard instruments there are four conically approximated Wolter-I X-ray mirrors, among which two of them are soft X-ray mirrors1, of which the energy range is from a few hundred eV to 15

  13. X-ray scatter tomography for explosives detection

    Microsoft Academic Search

    G. Harding

    2004-01-01

    An account is given of three explosive detection techniques based on X-ray scatter tomography i.e. coherent scatter computed tomography, energy–dispersive X-ray diffraction tomography and Compton back-scatter imaging. Following an introduction to the physics of the underlying X-ray interaction phenomena, the principles on which these image-forming techniques are based are elaborated. A brief description is given of some of the parameters

  14. Fluorescent X-ray transport in microchannel plates

    NASA Astrophysics Data System (ADS)

    Mazuritskiy, M. I.

    2006-12-01

    The X-ray absorption spectra of microchannel plates have been measured at grazing incidence of the primary radiation. The Si L components of X-ray absorption near-edge structure (XANES) spectra exhibit specific features for incident angles below a certain critical value. In order to explain the experimental data, a mechanism of selective X-ray fluorescence transport via microchannels is proposed, which is based on the notion of anomalous dispersion in the vicinity of the Si L absorption edge.

  15. Direct chlorine determination in crude oils by energy dispersive X-ray fluorescence spectrometry: An improved method based on a proper strategy for sample homogenization and calibration with inorganic standards

    NASA Astrophysics Data System (ADS)

    Doyle, Adriana; Saavedra, Alvaro; Tristão, Maria Luiza B.; Nele, Márcio; Aucélio, Ricardo Q.

    2011-05-01

    Official guidelines to perform chlorine determination in crude oil are (i) American Society for Testing and Materials (ASTM) D6470, which is based on the extraction of water from the oil and subsequent determination of the chloride by potentiometry, (ii) ASTM D3230, that measures the conductivity of a solution of crude oil in a mixture of organic solvents and (iii) US Environmental Protection Agency (EPA) 9075 that uses energy dispersive X-ray fluorescence spectrometry to quantify chlorine and it is applicable for the range from 200 ?g g - 1 to percent levels of the analyte. The goal of this work is to propose method to quantify lower amounts of chlorine in crude oil using energy dispersive X-ray fluorescence spectrometry using a simple calibration strategy. Sample homogenization procedure was carefully studied in order to enable accurate results. The calibration curve was made with standards prepared by diluting aqueous NaCl standard in glycerin. The method presented a linear response that covers the range from 8 to at least 100 ?g g - 1 of chlorine. Chlorine in crude oil samples from Campos Basin - Brazil were quantified by the proposed method and by potentiometry after extraction of chlorine from the oil. Results achieved using both methods were statistically the same at 95% confidence level.

  16. All-Optical Tb\\/S 3R Wavelength Conversion Using Dispersion-Managed Light Bullets

    Microsoft Academic Search

    Lu Gao; Kelvin H. Wagner; Robert R. McLeod

    2008-01-01

    We present an all-optical wavelength converter that can operate at a very-high-switching rate with simultaneous reshaping, retiming, and regenerating (3R) capabilities based on nonlinear interactions between dispersion-managed (DM) (3+1)-dimensional optical solitons (light bullets). Numerical simulations have been performed to demonstrate the generation of the DM light bullets and the spatial dragging interaction between solitons with different colors for ultrafast wavelength

  17. Zero-dispersion wavelength uniformity and four-wave mixing in optical fiber

    Microsoft Academic Search

    J. B. Schlager; S. E. Mechels; D. L. Franzen

    1996-01-01

    The efficiency of four-wave mixing (FWM) in optical fiber is maximum with optimal phase matching at the zero-dispersion wavelength, but this wavelength can vary along the fiber's length. In this paper, we describe measurements of partially degenerate four-wave mixing efficiency in a 10 km fiber with varying ?o. In partially degenerate four-wave mixing the pump provides two of the four

  18. Multiple dispersed phases in a high-strength low-carbon steel: An atom-probe tomographic and synchrotron X-ray diffraction study

    SciTech Connect

    Mulholland, Michael D.; Seidman, David N.; (NWU)

    2009-06-12

    The co-precipitation of Cu, M{sub 2}C (where M is any combination of Cr, Mo or Ti) and austenite (face-centered cubic) is characterized for 5 h isochronal aging times by synchrotron X-ray diffraction and three-dimensional atom-probe tomography for a high-strength low-carbon steel, BlastAlloy 160. High number densities, {approx}10{sup 23} m{sup 03}, of co-located Cu and M{sub 2}C preciptates were observed. Only small austenite volume percentages (<2.1%) were measured after aging at temperatures up to 625 C for 5 h.

  19. Crystallization and X-ray Diffraction Analysis of a Novel Immune-Type Receptor from Ictalurus punctatus and Phasing by Selenium Anomalous Dispersion Methods

    SciTech Connect

    Ostrov,D.; Hernandez Prada, J.; Haire, R.; Cannon, J.; Magis, A.; Bailey, K.; Litman, G.

    2007-01-01

    X-ray diffraction data from crystals of a novel immune-type receptor (NITR10 from the catfish Ictalurus punctatus) were collected to 1.65 Angstroms resolution and reduced to the primitive hexagonal lattice. Native and selenomethionine derivatives of NITR10 crystallized under different conditions yielded P3121 crystals. SeMet NITR10 was phased to a correlation coefficient of 0.77 by SAD methods and experimental electron-density maps were calculated to 1.65 Angstroms . Five NITR10 molecules are predicted to be present in the asymmetric unit based on the Matthews coefficient.

  20. Nonlinear wavelength conversion in photonic crystal fibers with three zero-dispersion points

    SciTech Connect

    Stark, S. P.; Biancalana, F.; Podlipensky, A.; St. J. Russell, P. [Max Planck Institute for the Science of Light Guenther-Scharowsky Str. 1/Bau 24, D-91058 Erlangen (Germany)

    2011-02-15

    In this theoretical study, we show that a simple endlessly single-mode photonic crystal fiber can be designed to yield, not just two, but three zero-dispersion wavelengths. The presence of a third dispersion zero creates a rich phase-matching topology, enabling enhanced control over the spectral locations of the four-wave-mixing and resonant-radiation bands emitted by solitons and short pulses. The greatly enhanced flexibility in the positioning of these bands has applications in wavelength conversion, supercontinuum generation, and pair-photon sources for quantum optics.

  1. Nonlinear wavelength conversion in photonic crystal fibers with three zero dispersion points

    E-print Network

    Stark, S P; Podlipensky, A; Russell, P St J

    2010-01-01

    In this theoretical study, we show that a simple endlessly single-mode photonic crystal fiber can be designed to yield, not just two, but three zero-dispersion wavelengths. The presence of a third dispersion zero creates a rich phase-matching topology, enabling enhanced control over the spectral locations of the four-wave-mixing and resonant-radiation bands emitted by solitons and short pulses. The greatly enhanced flexibility in the positioning of these bands has applications in wavelength conversion, supercontinuum generation and pair-photon sources for quantum optics.

  2. Control of Wavelength Dispersion of Birefringence for Oriented Copolycarbonate Films Containing Positive and Negative Birefringent Units

    NASA Astrophysics Data System (ADS)

    Uchiyama, Akihiko; Yatabe, Toshiaki

    2003-11-01

    The wavelength dispersion of birefringence for uniaxially oriented copolycarbonate films containing positive and negative birefringent units has been examined by polarization-modulated transmission spectro-ellipsometry, as a function of copolymerization ratio and stretching parameters. The copolymers were synthesized from 2,2-bis(4-hydroxyphenyl)propane (BPA), 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (BMPF) and phosgene by interfacial polycondensation. The films indicate reverse dispersion in the region of BMPF volume fraction from 0.65 to 0.80. The wavelength dispersion is controlled by the copolymerization ratio. The dispersion change of the 70 mol% BMPF copolycarbonate films as a function of stretching parameters is negligible. These behaviors are explained by the birefringence equation for a multicomponent system of the copolymer.

  3. GOES-SXI views the Sun in X-rays

    NSDL National Science Digital Library

    Tom Bridgman

    2003-01-30

    The Solar X-ray Imager (SXI) aboard GOES-12 went online for full-time operation on January 22, 2003. It provides full-disk X-ray images of the Sun updated every few minutes. This movie covers the band 0.6-6.0 nanometers wavelength.

  4. X-RAY GROUPS OF GALAXIES IN THE AEGIS DEEP AND WIDE FIELDS

    SciTech Connect

    Erfanianfar, G.; Lerchster, M.; Nandra, K.; Connelly, J. L.; Mirkazemi, M. [Max Planck-Institute for Extraterrestrial Physics, P.O. Box 1312, Giessenbachstr. 1., D-85741 Garching (Germany); Finoguenov, A. [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, FI-00014 Helsinki (Finland); Tanaka, M. [Institute for the Physics and Mathematics of the Universe, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8583 (Japan); Laird, E. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Bielby, R. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Faber, S. M.; Kocevski, D.; Jeltema, T. [UCO/Lick Observatories, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Cooper, M. [Center for Galaxy Evolution, Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States); Newman, J. A. [Department of Physics and Astronomy, University of Pittsburgh, 401-C Allen Hall, 3941 O'Hara Street, Pittsburgh, PA 15260 (United States); Coil, A. L. [Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Drive, MC 0424, San Diego, CA 92093 (United States); Brimioulle, F. [University Observatory Munich, Ludwigs-Maximilians University Munich, Scheinerstr. 1, D-81679 Munich (Germany); Davis, M. [Department of Astronomy, University of California, Berkeley, Berkeley, CA 94720 (United States); McCracken, H. J. [Institut d'Astrophysique de Paris, UMR 7095 CNRS, Universite Pierre et Marie Curie, 98 bis boulevard Arago, F-75014 Paris (France); Willmer, C. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Gerke, B., E-mail: erfanian@mpe.mpg.de [Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 90R4000, Berkeley, CA 94720 (United States); and others

    2013-03-10

    We present the results of a search for extended X-ray sources and their corresponding galaxy groups from 800 ks Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). This yields one of the largest X-ray-selected galaxy group catalogs from a blind survey to date. The red-sequence technique and spectroscopic redshifts allow us to identify 100% of reliable sources, leading to a catalog of 52 galaxy groups. These groups span the redshift range z {approx} 0.066-1.544 and virial mass range M{sub 200} {approx} 1.34 Multiplication-Sign 10{sup 13}-1.33 Multiplication-Sign 10{sup 14} M{sub Sun }. For the 49 extended sources that lie within DEEP2 and DEEP3 Galaxy Redshift Survey coverage, we identify spectroscopic counterparts and determine velocity dispersions. We select member galaxies by applying different cuts along the line of sight or in projected spatial coordinates. A constant cut along the line of sight can cause a large scatter in scaling relations in low-mass or high-mass systems depending on the size of the cut. A velocity-dispersion-based virial radius can cause a larger overestimation of velocity dispersion in comparison to an X-ray-based virial radius for low-mass systems. There is no significant difference between these two radial cuts for more massive systems. Independent of radial cut, an overestimation of velocity dispersion can be created in the case of the existence of significant substructure and compactness in X-ray emission, which mostly occur in low-mass systems. We also present a comparison between X-ray galaxy groups and optical galaxy groups detected using the Voronoi-Delaunay method for DEEP2 data in this field.

  5. 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.

  6. X-ray Crystallography

    NSDL National Science Digital Library

    In this activity, by the Concord Consortium's Molecular Literacy project, students are introduced to the fundamental principles of X-ray crystallography and "guides students through a series of activities for learning how structural information can be derived from X-ray diffraction patterns." Upon completion of this activity students should be able to describe what can be detected with X-ray crystallography (proteins in particular) and explain the impact of temperature, atom size, and impurities in the test. The activity itself is a java-based interactive resource built upon the free, open source Molecular Workbench software. In the activity, students are allowed to explore at their own pace in a digital environment full of demonstrations, illustrations, and models they can manipulate. In addition to the activity, visitors will find an overview of the activity, a test and rubric, central concepts, and their correlation to AAAS standards.

  7. Nonlinear wavelength conversion in photonic crystal fibers with three zero-dispersion points

    Microsoft Academic Search

    S. P. Stark; F. Biancalana; A. Podlipensky; P. St. J. Russell

    2011-01-01

    In this theoretical study, we show that a simple endlessly single-mode photonic crystal fiber can be designed to yield, not just two, but three zero-dispersion wavelengths. The presence of a third dispersion zero creates a rich phase-matching topology, enabling enhanced control over the spectral locations of the four-wave-mixing and resonant-radiation bands emitted by solitons and short pulses. The greatly enhanced

  8. 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

  9. X-ray microtomography

    SciTech Connect

    Landis, Eric N., E-mail: landis@maine.edu [Department of Civil and Environmental Engineering, University of Maine, 5711 Boardman Hall, Orono, Maine 04469 (United States); Keane, Denis T., E-mail: dtkeane@northwestern.edu [Department of Materials Science and Engineering, Northwestern University (United States); DND-CAT, Advanced Photon Source, Argonne National Laboratory, Bldg. 432/A002, 9700 S. Cass Ave, Argonne, Illinois 60439 (United States)

    2010-12-15

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

  10. Dispersion measurement of optical fiber using dual wavelength diffraction phase microscope

    NASA Astrophysics Data System (ADS)

    Jafarfard, Mohammad Reza; Tayebi, Behnam; Nasab, Razie Jalai; Kim, Dug Young

    2014-11-01

    Various quantitative phase microscopy (QPM) techniques for noninvasive and quantitative analysis of samples proposed based on imaging interferometry techniques over the last decade [1-4]. A phase image can be obtained with a single set of interference data in some types of phase microscopes such as diffraction phase microscope [5, 6]. They are suitable for studying rapidly varying phenomena with reduced concern for systematic and sample variations that may occur during the acquisition of the raw data. Dispersion measurements of a sample carry more information than refractive index of measurements at a single wavelength [7]. Knowledge of the optical dispersion for phase objects such as optical fibers, biological cells and micro-particles can provide very useful information about their property. In this work, we report on a common-path and dual wavelength quantitative phase microscope that simultaneously acquires two phase images at different wavelengths. The simultaneous dual-wavelength measurement was performed with a diffraction phase microscope based on a transmission grating and a spatial filter that form a common-path imaging interferometer. With a combined laser source that generates two-color light continuously, a different diffraction order of the grating was utilized for each wavelength component so that the dual-wavelength interference pattern could be distinguished by the distinct fringe frequencies. The refractive index profiles of fiber in both wavelengths were measured adequately by our DW-DPM system.

  11. X-ray second harmonic generation.

    PubMed

    Shwartz, S; Fuchs, M; Hastings, J B; Inubushi, Y; Ishikawa, T; Katayama, T; Reis, D A; Sato, T; Tono, K; Yabashi, M; Yudovich, S; Harris, S E

    2014-04-25

    We report clear experimental evidence for second harmonic generation at hard x-ray wavelengths. Using a 1.7 Å pumping beam generated by a free electron laser, we observe second harmonic generation in diamond. The generated second harmonic is of order 10 times the background radiation, scales quadratically with pump pulse energy, and is generated over a narrow phase-matching condition. Of importance for future experiments, our results indicate that it is possible to observe nonlinear x-ray processes in crystals at pump intensities exceeding 1016??W/cm2. PMID:24815649

  12. X-Ray Transition Energies Database

    National Institute of Standards and Technology Data Gateway

    SRD 128 X-Ray Transition Energies Database (Web, free access)   This X-ray transition table provides the energies and wavelengths for the K and L transitions connecting energy levels having principal quantum numbers n = 1, 2, 3, and 4. The elements covered include Z = 10, neon to Z = 100, fermium. There are two unique features of this data base: (1) a serious attempt to have all experimental values on a scale consistent with the International System of measurement (the SI) and (2) inclusion of accurate theoretical estimates for all transitions.

  13. X-ray-induced water vaporization

    SciTech Connect

    Weon, B. M.; Lee, J. S.; Je, J. H. [X-ray Imaging Center, Department of Materials Science and Engineering,Pohang University of Science and Technology, San 31, Pohang 790-784 (Korea, Republic of); Fezzaa, K. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

    2011-09-15

    We present quantitative evidence for x-ray-induced water vaporization: water is vaporized at a rate of 5.5 pL/s with the 1-A-wavelength x-ray irradiation of {approx}0.1 photons per A{sup 2}; moreover, water vapor is reversibly condensed during pauses in irradiation. This result fundamentally suggests that photoionization induces vaporization. This phenomenon is attributed to surface-tension reduction by ionization and would be universally important in radiological and electrohydrodynamic situations.

  14. 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

  15. X-ray emission from active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Mushotzky, R.

    1985-01-01

    It is often held that the X-ray emission from active galactic nuclei (AGN) arises from a region close to the central energy source. Thus X-ray observations may provide the best constraints on the central engine. In particular, the shape of the X-ray continuum gives information about the mechanism for photon generation, X-ray time variability data can constrain the size and mass of the continuum source, and X-ray occultation data give constraints on the relative sizes of the continuum source and the intervening absorbing material (often assumed to be the broad line clouds). In addition, since a fair fraction of the total energy of an AGN is emitted at X-ray wavelengths, direct measurement of the amount and spectral form of this radiation is important for modeling of the optically emitting clouds.

  16. X-Ray Spacing

    NSDL National Science Digital Library

    David Barthelmy

    This site features a collection of single-phase X-ray powder diffraction patterns for the three most intense D values of an extensive list of minerals. The information is presented in the form of tables of interplanar spacings (D), relative intensities, hkl plane. There are also links to more information about each mineral, such as chemical formula, composition, environment, and name origin.

  17. Spatial Equalization of Zero-Dispersion Wavelength Profiles in Nonlinear Fibers

    Microsoft Academic Search

    Evgeny Myslivets; Carl Lundstrom; Jose M. Aparicio; Slaven Moro; Andreas O. J. Wiberg; Camille-Sophie Bres; Nikola Alic; Peter A. Andrekson; Stojan Radic

    2009-01-01

    Longitudinal zero-dispersion wavelength (ZDW) fluctuations in long waveguides impose a fundamental limit on the achievable parametric mixer bandwidth. We demonstrate for the first time that the precisely measured ZDW profile can be taken advantage of by applying spatially controlled tension along the fiber length for fluctuation reduction and synthesis of a wide mixer response. The technique was experimentally validated by

  18. NIRCam Long Wavelength Channel grisms as the Dispersed Fringe Sensor for JWST segment mirror coarse phasing

    Microsoft Academic Search

    Fang Shi; Brian M. King; Norbert Sigrist; Scott A. Basinger

    2008-01-01

    The baseline wavefront sensing and control for James Webb Space Telescope (JWST) includes the Dispersed Hartmann Sensors (DHS) for segment mirror coarse phasing. The two DHS devices, residing on the pupil wheel of the JWST's Near Infrared Camera (NIRCam) Short Wavelength Channel (SWC), can sense the JWST segment mirror pistons by measuring the heights of 20 inter-segment edges from the

  19. A Soft X-ray Polarimeter Designed for Broad-band X-ray Telescopes

    E-print Network

    Herman L. Marshall

    2007-09-14

    A novel approach for measuring linear X-ray polarization over a broad-band using conventional imaging optics and cameras is described. A new type of high efficiency grating, called the critical angle transmission grating is used to disperse soft X-rays radially from the telescope axis. A set of multilayer-coated paraboloids re-image the dispersed X-rays to rings in the focal plane. The intensity variation around these rings is measured to determine three Stokes parameters: I, Q, and U. By laterally grading the multilayer optics and matching the dispersion of the gratings, one may take advantage of high multilayer reflectivities and achieve modulation factors over 50% over the entire 0.2 to 0.8 keV band. A sample design is shown that could be used with the Constellation-X optics.

  20. X-ray Free-electron Lasers

    SciTech Connect

    Feldhaus, J.; /DESY; Arthur, J.; Hastings, J.B.; /SLAC

    2007-02-23

    In a free-electron laser (FEL) the lasing medium is a high-energy beam of electrons flying with relativistic speed through a periodic magnetic field. The interaction between the synchrotron radiation that is produced and the electrons in the beam induces a periodic bunching of the electrons, greatly increasing the intensity of radiation produced at a particular wavelength. Depending only on a phase match between the electron energy and the magnetic period, the wavelength of the FEL radiation can be continuously tuned within a wide spectral range. The FEL concept can be adapted to produce radiation wavelengths from millimeters to Angstroms, and can in principle produce hard x-ray beams with unprecedented peak brightness, exceeding that of the brightest synchrotron source by ten orders of magnitude or more. This paper focuses on short-wavelength FELs. It reviews the physics and characteristic properties of single-pass FELs, as well as current technical developments aiming for fully coherent x-ray radiation pulses with pulse durations in the 100 fs to 100 as range. First experimental results at wavelengths around 100 nm and examples of scientific applications planned on the new, emerging x-ray FEL facilities are presented.

  1. Nonlinear X-ray Compton Scattering

    E-print Network

    Fuchs, Matthias; Chen, Jian; Ghimire, Shambhu; Shwartz, Sharon; Kozina, Michael; Jiang, Mason; Henighan, Thomas; Bray, Crystal; Ndabashimiye, Georges; Bucksbaum, P H; Feng, Yiping; Herrmann, Sven; Carini, Gabriella; Pines, Jack; Hart, Philip; Kenney, Christopher; Guillet, Serge; Boutet, Sebastien; Williams, Garth; Messerschmidt, Marc; Seibert, Marvin; Moeller, Stefan; Hastings, Jerome B; Reis, David A

    2015-01-01

    X-ray scattering is a weak linear probe of matter. It is primarily sensitive to the position of electrons and their momentum distribution. Elastic X-ray scattering forms the basis of atomic structural determination while inelastic Compton scattering is often used as a spectroscopic probe of both single-particle excitations and collective modes. X-ray free-electron lasers (XFELs) are unique tools for studying matter on its natural time and length scales due to their bright and coherent ultrashort pulses. However, in the focus of an XFEL the assumption of a weak linear probe breaks down, and nonlinear light-matter interactions can become ubiquitous. The field can be sufficiently high that even non-resonant multiphoton interactions at hard X-rays wavelengths become relevant. Here we report the observation of one of the most fundamental nonlinear X-ray-matter interactions, the simultaneous Compton scattering of two identical photons producing a single photon at nearly twice the photon energy. We measure scattered...

  2. X-ray lithography masking

    NASA Technical Reports Server (NTRS)

    Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

    1998-01-01

    X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

  3. Low energy x-ray spectrometer

    SciTech Connect

    Woodruff, W.R.

    1981-06-05

    A subkilovolt spectrometer has been produced to permit high-energy-resolution, time-dependent x-ray intensity measurements. The diffracting element is a curved mica (d = 9.95A) crystal. To preclude higher order (n > 1) diffractions, a carbon x-ray mirror that reflects only photons with energies less than approx. 1.1 keV is utilized ahead of the diffracting element. The nominal energy range of interest is 800 to 900 eV. The diffracted photons are detected by a gold-surface photoelectric diode designed to have a very good frequency response, and whose current is recorded on an oscilloscope. A thin, aluminium light barrier is placed between the diffracting crystal and the photoelectric diode detector to keep any uv generated on or scattered by the crystal from illuminating the detector. High spectral energy resolution is provided by many photocathodes between 8- and 50-eV wide placed serially along the diffracted x-ray beam at the detector position. The spectrometer was calibrated for energy and energy dispersion using the Ni L..cap alpha../sub 1/ /sub 2/ lines produced in the LLNL IONAC accelerator and in third order using a molybdenum target x-ray tube. For the latter calibration the carbon mirror was replaced by one surfaced with rhodium to raise the cut-off energy to about 3 keV. The carbon mirror reflection dependence on energy was measured using one of our Henke x-ray sources. The curved mica crystal diffraction efficiency was measured on our Low-Energy x-ray (LEX) machine. The spectrometer performs well although some changes in the way the x-ray mirror is held are desirable. 16 figures.

  4. Progress in Soft X-ray Polarimetry

    NASA Astrophysics Data System (ADS)

    Marshall, Herman L.; Schulz, N.; Heilmann, R.; Kochanski, K.

    2012-05-01

    We developed an instrument design capable of measuring linear X-ray polarization over a broad-band using conventional spectroscopic optics. A set of multilayer-coated flats reflects the dispersed X-rays to the instrument detectors. The intensity variation with position angle is measured to determine three Stokes parameters: I, Q, and U -- all as a function of energy. By laterally grading the multilayer optics and matching the dispersion of the gratings, one may take advantage of high multilayer reflectivities and achieve modulation factors >50% over the entire 0.2 to 0.8 keV band. This instrument could be used in a small orbiting mission or the approach could be used on a large dispersive spectrometric facility. We present progress on laboratory work to demonstrate the capabilities of key components. We thank the MIT Kavli Institute and the NASA Astrophysics Research and Analysis program for funding.

  5. Fluctuation X-Ray Scattering

    SciTech Connect

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

    2013-01-25

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

  6. Encapsulating X-Ray Detectors

    NASA Technical Reports Server (NTRS)

    Conley, Joseph M.; Bradley, James G.

    1987-01-01

    Vapor-deposited polymer shields crystals from environment while allowing X rays to pass. Polymer coating transparental to X rays applied to mercuric iodide detector in partial vacuum. Coating protects crystal from sublimation, chemical attack, and electrical degradation.

  7. X-Rays for Children

    MedlinePLUS

    ... Orthodontic X-rays (also called cephalometric or lateral skull) — This type of X-ray shows the head ... jaws and the relationship of bones in the skull. It helps an orthodontist make an accurate diagnosis ...

  8. In-situ synchrotron energy-dispersive x-ray diffraction study of thin Pd foils with Pd:D and Pd:H concentrations up to 1:1

    SciTech Connect

    Knies, D. L.; Grabowski, K. S.; Dominguez, D. D.; Qadri, S. B.; Hubler, G. K. [U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Violante, V. [ENEA, Frascati (Italy); Hu, J. Z. [NSLS, Brookhaven National Laboratory, Brookhaven, New York 11973 (United States); He, J. H. [Nova Research, Alexandria, Virginia 22308 (United States)

    2012-10-15

    Time resolved, in-situ, energy dispersive x-ray diffraction was performed in an electrolysis cell during electrochemical loading of palladium foil cathodes with hydrogen and deuterium. Concentrations of H:Pd (D:Pd) up to 1:1 in 0.1 M LiOH (LiOD) in H{sub 2}O (D{sub 2}O) electrolyte were obtained, as determined by both the Pd lattice parameter and cathode resistivity. In addition, some indications on the kinetics of loading and deloading of hydrogen from the Pd surface were obtained. The alpha-beta phase transformations were clearly delineated but no new phases at high concentration were determined.

  9. Holography at x-ray wavelengths

    SciTech Connect

    Solem, T.C.; Baldwin, G.C.; Chapline, G.F.

    1981-01-01

    We discuss alternative holographic techniques for imaging microscopic structures with a short-pulse, high intensity, high-quantum-energy laser. We find that Fresnel transform holography using a photoresist for registration of the hologram is most likely to be within the scope of near term technology. Although it has advantages in time gating, using an in-line electron microscope for hologram registration has an unacceptable tradeoff between quantum efficiency and resolution. Fourier transform holography using a reflector to generate the reference beam might be a reasonable alternative using low resolution film, but is necessarily more complicated. We discuss the dependence of the required laser intensity on the resolution sought and on the elastic and absorption cross sections. We conclude that resonant scattering must be used to obtain holograms at reasonable intensities.

  10. Bone X-Ray (Radiography)

    MedlinePLUS

    ... x-rays. top of page What does the equipment look like? View larger with caption The equipment typically used for bone x-rays consists of ... and joint abnormalities, such as arthritis. X-ray equipment is relatively inexpensive and widely available in emergency ...

  11. Evaluation of micro-energy dispersive X-ray fluorescence and histochemical tests for aluminium detection in plants from High Altitude Rocky Complexes, Southeast Brazil.

    PubMed

    Campos, Naiara V; Pereira, Tiago A R; Machado, Mariana F; Guerra, Marcelo B B; Tolentino, Gláucia S; Araújo, Josiane S; Rezende, Maíra Q; Silva, Maria Carolina N A da; Schaefer, Carlos E G R

    2014-03-01

    The soils developed under High Altitude Rocky Complexes in Brazil are generally of very low chemical fertility, with low base saturation and high exchangeable aluminium concentration. This stressful condition imposes evolutionary pressures that lead to ecological success of plant species that are able to tolerate or accumulate high amounts of aluminium. Several analytical methods are currently available for elemental mapping of biological structures, such as micro-X-ray fluorescence (?-EDX) and histochemical tests. The aim of this study was to combine ?-EDX analysis and histochemical tests to quantify aluminium in plants from High Altitude Rocky Complexes, identifying the main sites for Al-accumulation. Among the studied species, five showed total Al concentration higher than 1000 mg kg-1. The main Al-hyperaccumulator plants, Lavoisiera pectinata, Lycopodium clavatum and Trembleya parviflora presented positive reactions in the histochemical tests using Chrome Azurol and Aluminon. Strong positive correlations were observed between the total Al concentrations and data obtained by ?-EDX analysis. The ?-EDX analysis is a potential tool to map and quantify Al in hyperaccumulator species, and a valuable technique due to its non-destructive capacity. Histochemical tests can be helpful to indicate the accumulation pattern of samples before they are submitted for further ?-EDX scrutiny. PMID:24676168

  12. Site Specific X-ray Anomalous Dispersion of the Geometrically Frustrated Kagome´ Magnet Herbertsmithite ZnCu3(OH)6Cl2

    SciTech Connect

    A Freedman; T Han; A Prodi; P Muller; Q Huang; Y Chen; S Webb; Y Lee; T McQueen; D Nocera

    2011-12-31

    Structural characterization, exploiting X-ray scattering differences at elemental absorption edges, is developed to quantitatively determine crystallographic site-specific metal disorder. We apply this technique to the problem of Zn-Cu chemical disorder in ZnCu{sub 3}(OH){sub 6}Cl{sub 2}. This geometrically frustrated kagome antiferromagnet is one of the best candidates for a spin-liquid ground state, but chemical disorder has been suggested as a mundane explanation for its magnetic properties. Using anomalous scattering at the Zn and Cu edges, we determine that there is no Zn occupation of the intralayer Cu sites within the kagome layer; however there is Cu present on the Zn intersite, leading to a structural formula of (Zn{sub 0.85}Cu{sub 0.15})Cu{sub 3}(OH){sub 6}Cl{sub 2}. The lack of Zn mixing onto the kagome lattice sites lends support to the idea that the electronic ground state in ZnCu{sub 3}(OH){sub 6}Cl{sub 2} and its relatives is nontrivial.

  13. Wavelength dispersion of Verdet constants in chalcogenide glasses for magneto-optical waveguide devices

    Microsoft Academic Search

    Yinlan Ruan; Ruth A. Jarvis; Andrei V. Rode; Steve Madden; Barry Luther-Davies

    2005-01-01

    The wavelength dispersion of the Verdet constants of bulk As–S, As–Se–S, Ge–As–Se and Ga–La–S-based chalcogenide glasses has been investigated at wavelengths between 675 and 1550nm. Ge33As12Se55 was found to have the highest Verdet constant, 0.0485min\\/G.cm at 1550nm, 30 times that of silica. The high Verdet constant of Ge33As12Se55 is related to its smaller band gap energy compared with the other

  14. X-ray calibration of the GOES-N/O solar X-ray imagers

    NASA Astrophysics Data System (ADS)

    Catura, Paul R.; Gantner, Brennan L.; Jurcevich, Bruce K.; Kam, Claude K.; Lemen, James R.; Morrison, Mons D.; Shing, Lawrence; Catura, Richard C.

    2004-02-01

    The X-ray calibration of the GOES Solar X-ray Imagers (SXI) was accomplished at the component level and at the instrument level. The CCD and thin film filters were characterized in the facilities at the Lockheed Martin Solar and Astrophysics Laboratory. The grazing incidence telescope mirrors and the completed instruments were calibrated at the X-ray Calibration Facility (XRCF) at NASA"s Marshall Space Flight Center. The XRCF consists of an X-ray source at one end of a 518 m long evacuated tube and a large vacuum chamber at the opposite end. The X-ray source has a variety of interchangeable anodes and filters to provide filtered characteristic K- and L-shell line emission in the range from 0.109 to 8.6 keV. The absolute Photometric calibration of the SXI telescopes is very important for analysis and interpretation of their data, and to monitor the long-term solar variations at X-ray wavelengths. This paper describes the results of these calibrations.

  15. SOLITONS: Bright and dark pulses in optical fibres in the vicinity of the zero-dispersion wavelength

    NASA Astrophysics Data System (ADS)

    Molotkov, I. A.; Bisyarin, M. A.

    2004-02-01

    The influence of the third-order dispersion on the propagation of short pulses in optical fibres is considered. The appearance of coupled nonlinear structures consisting of dark and bright envelope solitons is described. The wavelength range is found in the vicinity of the zero-dispersion wavelength where the effect of the third-order dispersion on the pulse propagation proves to be dominant. It is shown that in this case a nonlinear structure in the form of an embedded soliton appears.

  16. Development of variable-magnification X-ray Bragg optics.

    PubMed

    Hirano, Keiichi; Yamashita, Yoshiki; Takahashi, Yumiko; Sugiyama, Hiroshi

    2015-07-01

    A novel X-ray Bragg optics is proposed for variable-magnification of an X-ray beam. This X-ray Bragg optics is composed of two magnifiers in a crossed arrangement, and the magnification factor, M, is controlled through the azimuth angle of each magnifier. The basic properties of the X-ray optics such as the magnification factor, image transformation matrix and intrinsic acceptance angle are described based on the dynamical theory of X-ray diffraction. The feasibility of the variable-magnification X-ray Bragg optics was verified at the vertical-wiggler beamline BL-14B of the Photon Factory. For X-ray Bragg magnifiers, Si(220) crystals with an asymmetric angle of 14° were used. The magnification factor was calculated to be tunable between 0.1 and 10.0 at a wavelength of 0.112?nm. At various magnification factors (M ? 1.0), X-ray images of a nylon mesh were observed with an air-cooled X-ray CCD camera. Image deformation caused by the optics could be corrected by using a 2 × 2 transformation matrix and bilinear interpolation method. Not only absorption-contrast but also edge-contrast due to Fresnel diffraction was observed in the magnified images. PMID:26134799

  17. Nonlinear wavelength conversion in photonic crystal fibers with three zero dispersion points

    Microsoft Academic Search

    S. P. Stark; F. Biancalana; A. Podlipensky; P. St. J. Russell

    2010-01-01

    In this theoretical study, we show that a simple endlessly single-mode\\u000aphotonic crystal fiber can be designed to yield, not just two, but three\\u000azero-dispersion wavelengths. The presence of a third dispersion zero creates a\\u000arich phase-matching topology, enabling enhanced control over the spectral\\u000alocations of the four-wave-mixing and resonant-radiation bands emitted by\\u000asolitons and short pulses. The greatly enhanced

  18. Jovian X-ray emissions

    NASA Technical Reports Server (NTRS)

    Waite, J. H.; Lewis, W. S.; Gladstone, G. R.; Fabian, A. C.; Brandt, W. N.

    1996-01-01

    The Einstein and Rosat observations of X-ray emissions from Jupiter are summarized. Jupiter's soft X-ray emission is observed to originate from the planet's auroral zones, and specifically, from its equatorial region. The processes responsible for these emissions are not established. The brightness distribution of the Jovian X-rays is characterized by the dependence on central meridian longitude and by north-south and morning-afternoon asymmetries. The X-rays observed during the impact of the comet Shoemaker-Levy 9 are believed to be impact-induced brightenings of the X-ray aurora.

  19. Fully parallel algorithm for simulating dispersion-managed wavelength-division-multiplexed optical fiber systems.

    PubMed

    Lushnikov, P M

    2002-06-01

    An efficient numerical algorithm is presented for massively parallel simulations of dispersion-managed wavelength-division-multiplexed optical fiber systems. The algorithm is based on a weak nonlinearity approximation and independent parallel calculations of fast Fourier transforms on multiple central processor units (CPUs). The algorithm allows one to implement numerical simulations M/2 times faster than a direct numerical simulation by a split-step method, where M is a number of CPUs in a parallel network. PMID:18026330

  20. Chemical analysis of uranium-niobium alloys by wavelength dispersive spectroscopy at the sigma complex

    SciTech Connect

    Papin, Pallas A.

    2012-06-01

    Uranium-niobium alloys play an important role in the nation's nuclear stockpile. It is possible to chemically quantify this alloy at a micron scale by using a technique know as wavelength dispersive spectroscopy. This report documents how this technique was used and how it is possible to reproduce measurements of this type. Discussion regarding the accuracy and precision of the measurements, the development of standards, and the comparison of different ways to model the matrices are all presented.

  1. Soft x-ray lasers

    SciTech Connect

    Matthews, D.L.; Rosen, M.D.

    1988-12-01

    One of the elusive dreams of laser physicists has been the development of an x-ray laser. After 25 years of waiting, the x-ray laser has at last entered the scientific scene, although those now in operation are still laboratory prototypes. They produce soft x rays down to about five nanometers. X-ray lasers retain the usual characteristics of their optical counterparts: a very tight beam, spatial and temporal coherence, and extreme brightness. Present x-ray lasers are nearly 100 times brighter that the next most powerful x-ray source in the world: the electron synchrotron. Although Lawrence Livermore National Laboratory (LLNL) is widely known for its hard-x-ray laser program which has potential applications in the Strategic Defense Initiative, the soft x-ray lasers have no direct military applications. These lasers, and the scientific tools that result from their development, may one day have a place in the design and diagnosis of both laser fusion and hard x-ray lasers. The soft x-ray lasers now in operation at the LLNL have shown great promise but are still in the primitive state. Once x-ray lasers become reliable, efficient, and economical, they will have several important applications. Chief among them might be the creation of holograms of microscopic biological structures too small to be investigated with visible light. 5 figs.

  2. Binary x-ray pulsars

    SciTech Connect

    Rappaport, S. (Massachusetts Inst. of Tech., Cambridge); Joss, P.C.

    1980-01-01

    Progress made over the last decade in the understanding of the binary x-ray pulsars is reviewed. The characteristics of the pulse profiles of the known binary x-ray pulsars are discussed, and observed variations in pulse period corresponding to the spin-up of the neutron star are considered. Determinations of the orbits and binary system parameters of the binary x-ray pulsars from measurements of pulse arrival times are then examined. Attention is also given to current problems in binary x-ray pulsars, including the apsidal motion test, which allows the determination of the mass distribution within a star, the x-ray source 4U 1626-67, which is believed to be a highly compact binary x-ray source, and the observation of very faint x-ray pulsars with the Einstein Observatory.

  3. Soft x-ray interferometry

    SciTech Connect

    Not Available

    1993-09-01

    The purpose of the soft x-ray interferometry workshop held at Lawrence Berkeley Laboratory was to discuss with the scientific community the proposed technical design of the soft x-ray Fourier-transform spectrometer being developed at the ALS. Different design strategies for the instrument`s components were discussed, as well as detection methods, signal processing issues, and how to meet the manufacturing tolerances that are necessary for the instrument to achieve the desired levels of performance. Workshop participants were encouraged to report on their experiences in the field of Fourier transform spectroscopy. The ALS is developing a Fourier transform spectrometer that is intended to operate up to 100 eV. The motivation is solely improved resolution and not the throughput (Jaquinot) or multiplex (Fellgett) advantage, neither of which apply for the sources and detectors used in this spectral range. The proposed implementation of this is via a Mach-Zehnder geometry that has been (1) distorted from a square to a rhombus to get grazing incidence of a suitable angle for 100 eV and (2) provided with a mirror-motion system to make the path difference between the interfering beams tunable. The experiment consists of measuring the emergent light intensity (I(x)) as a function of the path difference (x). The resolving power of the system is limited by the amount of path difference obtainable that is 1 cm (one million half-waves at 200{angstrom} wavelength) in the design thus allowing a resolving power of one million. The free spectral range of the system is limited by the closeness with which the function I(x) is sampled. It is proposed to illuminate a helium absorption cell with roughly 1%-band-width light from a monochromator thus allowing one hundred aliases without spectral overlap even for sampling of I(x) at one hundredth of the Nyquist frequency.

  4. Dual-state dissipative solitons from an all-normal-dispersion erbium-doped fiber laser: continuous wavelength tuning and multi-wavelength emission.

    PubMed

    Wu, Zhichao; Fu, Songnian; Chen, Changxiu; Tang, Ming; Shum, Perry; Liu, Deming

    2015-06-15

    We propose and experimentally demonstrate switchable operation of dissipative solitons (DSs) in an erbium-doped fiber laser. By managing normal dispersion of laser cavity, the 3-dB spectral bandwidth up to 8.1 nm can be obtained with the help of a semiconductor saturable absorber mirror. Using an inline polarizer, the fiber laser can be separately operated at either wavelength-tunable or multi-wavelength emission. The central wavelength of DS can be continuously tuned from 1554 to 1561 nm with its spectra maintaining standard rectangular shape. Alternatively, triple-wavelength DSs at 1535, 1544, and 1553 nm can be simultaneously obtained. PMID:26076236

  5. X-ray satellite

    NASA Technical Reports Server (NTRS)

    1985-01-01

    An overview of the second quarter 1985 development of the X-ray satellite project is presented. It is shown that the project is proceeding according to plan and that the projected launch date of September 9, 1987 is on schedule. An overview of the work completed and underway on the systems, subsystems, payload, assembly, ground equipment and interfaces is presented. Problem areas shown include cost increases in the area of focal instrumentation, the star sensor light scattering requirements, and postponements in the data transmission subsystems.

  6. Continuous-wave, short-wavelength infrared mixer using dispersion-stabilized highly-nonlinear fiber.

    PubMed

    Kuo, Bill P-P; Hirano, Masaaki; Radic, Stojan

    2012-07-30

    A new type of highly nonlinear fiber (HNLF) was designed and fabricated. The new HNLF was engineered to reduce dispersion shift due to transverse fluctuations while maintaining the modal confinement superior to that of the conventional fibers. The new design strategy was validated by the measurements of the global and local dispersive characteristics under considerable core and index profile deformation induced by tensile stress, which indicated that the dispersive and phase matching characteristics of the fiber did not change even under the highest tensile stress. The characteristics effectively decoupled tension-based Brillouin suppression from phase-matching impairments in parametric mixers for the first time. The new HNLF was used to demonstrate the first coherence-preserving mixer operating in the short-wavelength infrared (SWIR) band. The SWIR mixer was driven by continuous-wave near-infrared (NIR) pump and did not require pump phase dithering to suppress Brillouin scattering. PMID:23038393

  7. Paper-based diffusive gradients in thin films technique coupled to energy dispersive X-ray fluorescence spectrometry for the determination of labile Mn, Co, Ni, Cu, Zn and Pb in river water

    NASA Astrophysics Data System (ADS)

    Almeida, Eduardo de; Nascimento Filho, Virgílio Franco do; Menegário, Amauri Antonio

    2012-05-01

    The diffusive gradients in thin films (DGT) technique has shown enormous potential for labile metal monitoring in fresh water due to the preconcentration, time-integrated, matrix interference removal and speciation analytical features. In this work, the coupling of energy dispersive X-ray fluorescence (EDXRF) with paper-based DGT devices was evaluated for the direct determination of Mn, Co, Ni, Cu, Zn and Pb in fresh water. The DGT samplers were assembled with cellulose (Whatman 3 MM chromatography paper) as the diffusion layer and a cellulose phosphate ion exchange membrane (Whatman P 81 paper) as the binding agent. The diffusion coefficients of the analytes on 3 MM chromatography paper were calculated by deploying the DGT samplers in synthetic solutions containing 500 ?g L- 1 of Mn, Co, Ni, Cu, Zn and Pb (4 L at pH 5.5 and ionic strength at 0.05 mol L- 1). After retrieval, the DGT units were disassembled and the P 81 papers were dried and analysed by EDXRF directly. The 3 MM chromatographic paper diffusion coefficients of the analytes ranged from 1.67 to 1.87 × 10- 6 cm2 s- 1. The metal retention and phosphate group homogeneities on the P 81 membrane was studied by a spot analysis with a diameter of 1 mm. The proposed approach (DGT-EDXRF coupling) was applied to determine the analytes at five sampling sites (48 h in situ deployment) on the Piracicaba river basin, and the results (labile fraction) were compared with 0.45 ?m dissolved fractions determined by synchrotron radiation-excited total reflection X-ray fluorescence (SR-TXRF). The limits of detection of DGT-EDXRF coupling for the analytes (from 7.5 to 26 ?g L- 1) were similar to those obtained by the sensitive SR-TXRF technique (3.8 to 9.1 ?g L- 1).

  8. A CCD area detector for X-ray diffraction under high pressure for rotating anode source

    Microsoft Academic Search

    Amar Sinha; Alka B. Garg; V. Vijayakumar; B. K. Godwal; S. K. Sikka

    2000-01-01

    Details of a two-dimensional X-ray area detector developed using a charge coupled device, a image intensifier and a fibre\\u000a optic taper are given. The detector system is especially optimized for angle dispersive X-ray diffraction set up using rotating\\u000a anode generator as X-ray source. The performance of this detector was tested by successfully carrying out powder X-ray diffraction\\u000a measurements on various

  9. Iron redistribution in a zirconium alloy after neutron and proton irradiation studied by energy-dispersive X-ray spectroscopy (EDX) using an aberration-corrected (scanning) transmission electron microscope

    NASA Astrophysics Data System (ADS)

    Francis, E. M.; Harte, A.; Frankel, P.; Haigh, S. J.; Jädernäs, D.; Romero, J.; Hallstadius, L.; Preuss, M.

    2014-11-01

    Zirconium alloys used as cladding materials in nuclear reactors can exhibit accelerated irradiation induced growth, often termed linear growth, after sustained neutron irradiation. This phenomenon has been linked to the formation of -component dislocation loops and to the concentration of interstitial solute atoms. It is well documented for the Zircaloys that Fe dissolves from second phase particles (SPPs) during irradiation thus increasing the interstitial solute concentration in the matrix. However, no progress has yet been made into understanding whether a similar process occurs for the newer ZIRLO™ alloys. We aim to overcome this shortcoming here by studying compositional changes in second phase particles in Low Tin ZIRLO™ after neutron and proton irradiation using energy dispersive X-ray (EDX) spectroscopy. Material irradiated to 18 dpa (displacements per atom) using neutrons and to 2.3 and 7 dpa by protons was investigated. The results show that Fe is lost from Zr-Nb-Fe-SPPs during both neutron and proton irradiation. Prior to irradiation, Fe was detected at the interface of ?-Nb-SPPs. This Fe enrichment is also dispersed during irradiation. Qualitatively, excellent agreement was found regarding the elemental redistribution processes observed after proton and neutron irradiation.

  10. X-ray microscopy of human malaria

    SciTech Connect

    Magowan, C.; Brown, J.T.; Mohandas, N.; Meyer-Ilse, W. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

    1997-04-01

    Associations between intracellular organisms and host cells are complex and particularly difficult to examine. X-ray microscopy provides transmission images of subcellular structures in intact cells at resolutions superior to available methodologies. The spatial resolution is 50-60nm with a 1 micron depth of focus, superior to anything achievable with light microscopy. Image contrast is generated by differences in photoelectric absorption by the atoms in different areas (i.e. subcellular structures) throughout the full thickness of the sample. Absorption due to carbon dominates among all the elements in the sample at 2.4 nm x-ray wavelength. Thus images show features or structures, in a way not usually seen by other types of microscopy. The authors used soft x-ray microscopy to investigate structural development of Plasmodium falciparum malaria parasites in normal and genetically abnormal erythrocytes, and in infected erythrocytes treated with compounds that have anti-malarial effects. X-ray microscopy showed newly elaborated structures in the cytosol of unstained, intact erythrocytes, redistribution of mass (carbon) in infected erythrocytes, and aberrant parasite morphology. Better understanding of the process of intracellular parasite maturation and the interactions between the parasite and its host erythrocyte can help define new approaches to the control of this deadly disease.

  11. Massively parallel X-ray holography

    SciTech Connect

    Spence, John C.H [Arizona State University; Marchesini, Stefano [Lawrence Berkeley National Laboratory, Berkeley; Boutet, Sebastien [Stanford Synchrotron Radiation Laboratory; Sakdinawat, Anne E. [, Lawrence Berkeley National Laboratory; Bogan, Michael J. [Lawrence Livermore National Laboratory; Bajt, Sasa [Lawrence Livermore National Laboratory; Barty, Anton [Lawrence Livermore National Laboratory; Chapman, Henry N. [Lawrence Livermore National Laboratory; Frank, Matthias [Lawrence Livermore National Laboratory; Hau-Riege, Stefan P. [Lawrence Livermore National Laboratory; Szöke, Abraham [Lawrence Livermore National Laboratory; Cui, Congwu [Lawrence Berkeley National Laboratory; Shapiro, David A. [Lawrence Berkeley National Laboratory; Howells, MAlcolm R. [Lawrence Berkeley National Laboratory; Shaevitz, Joshua W [Lewis-Sigler Institute; Lee, Joanna Y. [University of California, Berkeley; Hajdu, Janos [3Stanford Synchrotron Radiation Laboratory; Seibert, Marvin M. [Uppsala University

    2008-08-01

    Advances in the development of free-electron lasers offer the realistic prospect of nanoscale imaging on the timescale of atomic motions. We identify X-ray Fourier-transform holography1,2,3 as a promising but, so far, inefficient scheme to do this. We show that a uniformly redundant array4 placed next to the sample, multiplies the efficiency of X-ray Fourier transform holography by more than three orders of magnitude, approaching that of a perfect lens, and provides holographic images with both amplitude- and phase-contrast information. The experiments reported here demonstrate this concept by imaging a nano-fabricated object at a synchrotron source, and a bacterial cell with a soft-X-ray free-electron laser, where illumination by a single 15-fs pulse was successfully used in producing the holographic image. As X-ray lasers move to shorter wavelengths we expect to obtain higher spatial resolution ultrafast movies of transient states of matter

  12. Experimental observation of long-wavelength dispersive wave generation induced by self-defocusing nonlinearity in BBO crystal

    E-print Network

    Zhou, Binbin

    2015-01-01

    We experimentally observe long-wavelength dispersive waves generation in a BBO crystal. A soliton was formed in normal GVD regime of the crystal by a self-defocusing and negative nonlinearity through phase-mismatched quatradic interaction. Strong temporal pulse compression confirmed the formation of soliton during the pulse propagation inside the crystal. Significant dispersive wave radiation was measured in the anomalous GVD regime of the BBO crystal. With the pump wavelengths from 1.24 to 1.4 $\\mu$m, tunable dispersive waves are generated around 1.9 to 2.2 $\\mu$m. The observed dispersive wave generation is well understood by simulations.

  13. The x-ray crystal structure of lysine-2,3-aminomutase from Clostridium subterminale

    Microsoft Academic Search

    Bryan W. Lepore; Frank J. Ruzicka; Perry A. Frey; Dagmar Ringe

    2005-01-01

    The x-ray crystal structure of the pyridoxal-5'-phosphate (PLP), S-adenosyl-l-methionine (SAM), and [4Fe-4S]-dependent lysine-2,3-aminomutase (LAM) of Clostridium subterminale has been solved to 2.1-Å resolution by single-wavelength anomalous dispersion methods on a l-selenomethionine-substituted complex of LAM with [4Fe-4S]2+, PLP, SAM, and l-alpha-lysine, a very close analog of the active Michaelis complex. The unit cell contains a dimer of hydrogen-bonded, domain-swapped dimers, the

  14. Compact graphene mode-locked wavelength-tunable erbium-doped fiber lasers: from all anomalous dispersion to all normal dispersion

    Microsoft Academic Search

    H. Zhang; D. Y. Tang; L. M. Zhao; Q. L. Bao; K. P. Loh; B. Lin; S. C. Tjin

    2010-01-01

    Soliton operation and soliton wavelength tuning of erbium-doped fiber lasers mode locked with atomic layer graphene was experimentally investigated under various cavity dispersion conditions. It was shown that not only wide range soliton wavelength tuning but also soltion pulse width variation could be obtained in the fiber lasers. Our results show that the graphene mode locked erbium-doped fiber lasers provide

  15. Miniature x-ray source

    DOEpatents

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

    2002-01-01

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

  16. Solar X-ray physics

    SciTech Connect

    Bornmann, P.L. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

    1991-01-01

    Research on solar X-ray phenomena performed by American scientists during 1987-1990 is reviewed. Major topics discussed include solar images observed during quiescent times, the processes observed during solar flares, and the coronal, interplanetary, and terrestrial phenomena associated with solar X-ray flares. Particular attention is given to the hard X-ray emission observed at the start of the flare, the energy transfer to the soft X-ray emitting plasma, the late resolution of the flare as observed in soft X-ray, and the rate of occurrence of solar flares as a function of time and latitude. Pertinent aspects of nonflaring, coronal X-ray emission and stellar flares are also discussed. 175 refs.

  17. 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.

  18. Generation of intense ultrashort x-ray pulses

    SciTech Connect

    Eder, D.C.; London, R.A.; Rosen, M.D. [Lawrence Livermore National Lab., CA (United States); Strobel, G.L. [Georgia Univ., Macon, GA (United States)

    1993-08-01

    Modeling of x-ray emission from targets heated by an ultrashort-pulse high-intensity optical laser is discussed. One application, using the emitted x rays, is pumping inner-shell photo-ionized x-ray lasers. Short wavelength lasing ({lambda} {le} 15 {Angstrom}) requires fast rise-time 1--3 key x rays to ionize inner K-shell electrons. It has been shown that structured targets, consisting of grooves on a solid material or a composite of clusters, have high absorption. We model grooved targets as an ensemble of exploding foils finding that the rise time of x rays is rapid enough for pumping inner-shell x-ray lasers. We show that simple atomic models can overestimate the energy in x-ray emission bands. High-Z materials are found to have the highest conversion efficiency but mid-Z materials can be used to provide a band of emission at a particular energy. We show that the pondermotive inhibition of expansion has only a small effect on the x-ray emission. The emission of a Au plasma is found to be appropriate for pumping inner-shell lasing at 14.6 {Angstrom} in Ne. The required optical laser intensity is of order 10{sup 17} W/cm{sup 2} using a 100 fsec FWHM duration pulse. To produce a laser with a gain-length product of order 10 requires 5--15 J of optical energy.

  19. Results from a Grazing Incidence X-Ray Interferometer

    NASA Technical Reports Server (NTRS)

    Joy, Marshall K.; Shipley, Ann; Cash, Webster; Carter, James

    2000-01-01

    A prototype grazing incidence interferometer has been built and tested at EUV and X-ray wavelengths using a 120 meter long vacuum test facility at Marshall Space Flight Center. We describe the design and construction of the interferometer, the EUV and x-ray sources, the detector systems, and compare the interferometric fringe measurements with theoretical predictions. We also describe the next-generation grazing incidence system which is designed to provide laboratory demonstration of key technologies that will be needed for a space-based x-ray interferometer.

  20. Flat supercontinuum generation pumped by femtosecond pulses in zero-dispersion wavelength of photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Guo, Yuan; Ruan, Shuangchen; Yu, Yongqin; Du, Chenlin; Yan, Peiguang

    2009-10-01

    Two kinds of supercontinuum (SC) sources are successfully generated by propagating 200-fs unamplified and amplified pulses through a 0.85-m long nonlinear photonic crystal fiber (PCF), respectively. The spectra bandwidth of amplified-femtosecond-pumped SC is about 870 nm spanning 480 nm to 1350 nm, which is flat to 1.2dB over 100 nm spreading from 550nm to 650 nm. With the same PCF, SC spectra pumped by unamplified-femtosecond-pulses are narrower and unevener. A detailed simulation is carried out to help us understand the mechanism of supercontinuum evolution. For pump wavelength located at the zero dispersion wavelength of the PCF, spectra are broadened by the interaction between SPM and higher-order dispersion at early stage. With increasing the pump power, the spectra are broadened by fission of higher solitons and parametric four-wave mixing (FWM). When the peak power is up to mega-watt, FWM plays a notable role in flattening and further broadening the supercontinuum spectra in short wavelength side. An effective way to generate a flat SC laser source pumped by femtosecond pulses is also demonstrated.

  1. Topological X-Rays Revisited

    ERIC Educational Resources Information Center

    Lynch, Mark

    2012-01-01

    We continue our study of topological X-rays begun in Lynch ["Topological X-rays and MRI's," iJMEST 33(3) (2002), pp. 389-392]. We modify our definition of a topological magnetic resonance imaging and give an affirmative answer to the question posed there: Can we identify a closed set in a box by defining X-rays to probe the interior and without…

  2. X-ray crystal interferometers

    NASA Astrophysics Data System (ADS)

    Lider, V. V.

    2014-11-01

    Various configurations of the X-ray crystal interferometer are reviewed. The interferometer applications considered include metrology, the measurement of fundamental physical constants, the study of weakly absorbing phase objects, time-resolved diagnostics, the determination of hard X-ray beam parameters, and the characterization of structural defects in the context of developing an X-ray Michelson interferometer. The three-crystal Laue interferometer (LLL-interferometer), its design, and the experimental opportunities it offers are given particular attention.

  3. Lawrence Livermore National Laboratory Soft X-ray Laser Program: Progress report

    SciTech Connect

    Trebes, J.; Brown, S.; Campbell, E.M.; Ceglio, N.; Eder, D.; Gaines, D.; Hawryluk, A.; Keane, C.; London, R.; MacGowan, B.

    1987-08-01

    Significant progress toward the goal of producing high power, high coherence x-ray lasers has been made. Lasing at wavelengths as low as 66 A has been achieved in a nickel like laser scheme which is scalable to sub-44 A wavelengths. In addition, x-ray laser cavities, x-ray holography, and an applications beamline have been demonstrated. 15 refs., 3 figs.

  4. Energy-Dispersive X-ray Diffraction Investigation of Amorphous Lithium Borate Structure: A Demonstration of the Paris-Edinburgh Cell Setup at 16BM-B at the APS

    NASA Astrophysics Data System (ADS)

    Yu, T.; Wang, Y.; Park, C.; Stebbins, J. F.; Sakamaki, T.; Shen, G.

    2010-12-01

    Knowledge of the structure and physical properties of silicate melts at a fundamental level is essential to help us understand the dynamics of mineral crystallization and fractionation, magma activities, thermal transport, etc. inside the Earth. The boron coordination number change due to pressure might be analogous to what happens on silicates at high pressure. Therefore, to understand the structure behavior under extreme pressure and temperature conditions in disordered silicates, borates are good cases to start with. And eventually we hope to apply the experimental method to silicates that are important in Earth Science. Results from previous NMR, Raman, and neutron diffraction studies on borate glasses show that boron has mixed coordination numbers that vary strongly with composition and temperature [Cormier et al., 2006]. Inelastic x-ray scattering of borate glass structure under pressure has been studied by Lee et al. [Lee et al., 2007]. However, studies of the pressure effect on liquid alkali borate structure are limited. In situ high pressure and high temperature x-ray total scattering of liquid state alkali borate has not even been reported. A 230-ton Paris-Edinburgh (PE) Press has been installed at Beamline 16BM-B at the Advanced Photon Source, Argonne National Laboratory since June 2010. The PE Cell is capable of generating high pressure up to ~10GPa and can heat the sample cell up to 2100K in temperature. The bending magnet white beam spanning a large energy range up to 120 KeV provides sufficient energy to reach our experimental needs. The germanium solid state detector is mounted on a Huber rotation stage, which allows us to collect diffraction signal at two theta angles as high as 39.5 degrees. This, combined with the broad white beam spectrum, will provide a large Q range up to about 40 inverse Angstroms, making this setup an ideal beamline for studying non-crystalline materials. We have successfully collected high pressure (up to 7GPa) and high temperature (up to 1673K) energy-dispersive x-ray diffraction data for lithium borate glass and liquid. The preliminary result is promising and it demonstrates that the PE setup at Beamline 16-BM-B is capable of producing good quality structure data for amorphous materials and melts. We observed systematic shifts in peak positions with change of pressure in the reconstructed structure factors. However, further work needs to be done in order to completely understand our data and the pressure-induced structure change of alkali borates. Structure modeling of the detected atomic coordination number change between three-coordinated boron ([3]B) and four-coordinated boron ([4]B) may also be compared with previous experimental results from other methods to justify the validity of the x-ray total scattering method on studying borate melts. Equally important, this project will help us continue to develop the PE system, so that it will be ready for general users.

  5. An x-ray probe of laser-aligned molecules

    Microsoft Academic Search

    E. R. Peterson; Christian Buth; D. A. Arms; R. W. Dunford; E. P. Kanter; B. Krässig; E. C. Landahl; S. T. Pratt; Robin Santra; S. H. Southworth; Linda Young

    2008-01-01

    We demonstrate a hard x-ray probe of laser-aligned small molecules. To align small molecules with optical lasers, high intensities at nonresonant wavelengths are necessary. We use 95 ps pulses focused to 40 mum from an 800 nm Ti:sapphire laser at a peak intensity of 1012 W\\/cm2 to create an ensemble of aligned bromotrifluoromethane (CF3Br) molecules. Linearly polarized, 120 ps x-ray

  6. Design and application of X-ray lasers

    Microsoft Academic Search

    Gulcin Eker

    2000-01-01

    Research with multiple optical laser pumping has lead to increased efficiency and shorter wavelength saturated X- ray lasing action in collisionally excited Ne-like and Ni-like ions. In particular, experiments and simulations have been undertaken to understand collisional X-ray lasers and their potential use as probing diagnostics of laser fusion plasmas. The scaling of Ni-like lasers with atomic number and the

  7. Vacuum spark point source for x-ray\\/EUV lithography

    Microsoft Academic Search

    Xioming Guo; Meisheng Xu; Rubin Ye; Chaofeng Huang; Kazimierz W. Wirpszo; Emilio Panarella

    2001-01-01

    The Vacuum Spark X-ray Source (VSX) embodies a miniature, high-repetition rate discharge emitting radiation in a broad spectrum optimized to emit soft X-rays with about 10 + wavelength. We have obtained over 100 (mu) J of energy per pulse in a narrow bandwidth centered around 7 Angstroms and pulse width less than 30 ns. The system operates with an ALFT

  8. Filters for soft X-ray solar telescopes

    NASA Technical Reports Server (NTRS)

    Spiller, Eberhard; Grebe, Kurt; Golub, Leon

    1990-01-01

    Soft X-ray telescopes require filters that block visible and infrared light and have good soft X-ray transmission. The optical properties of possible materials are discussed, and the fabrication and testing methods for the filters used in a 10-inch normal incidence telescope for 63 A are described. The best performances in the 44-114-A wavelength range are obtained with foils of carbon and rhodium.

  9. 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.

  10. X-Ray Data Booklet

    NSDL National Science Digital Library

    Attwood, David.

    2000-01-01

    The X-Ray Data Booklet is provided by the Center for X-ray Optics and Advanced Light Source of the Lawrence Berkeley National Laboratory, which is funded by the US Department of Energy. The online publication contains topics such as x-ray properties of elements, mass absorption coefficients, synchrotron radiation, scattering processes, low-energy electron ranges in matter, optics and detectors, specular reflectivities for grazing-incidence mirrors, and other practical information that has been produced and gathered as a result of research at the center. Additional features of the informative site include an interactive periodic table of X-Ray properties and free deliverable hardcopies of the document.

  11. X-ray fluorescence and X-ray transmission microtomography imaging system

    NASA Astrophysics Data System (ADS)

    Pereira, Gabriela R.; Rocha, Henrique S.; Anjos, Marcelino J.; Faria, Paulo; Pérez, Carlos A.; Lopes, Ricardo T.

    2007-10-01

    An X-ray Transmission Microtomography (CT) system combined with an X-ray Fluorescence Microtomography (XRFCT) system was implemented in the Brazilian Synchrotron Light Source (LNLS), Campinas, Brazil. The main aim of this work is to determine the elemental and absorption distribution map in breast tissue samples. The experiments were performed at the X-Ray Fluorescence beamline (D09B-XRF) of the Brazilian Synchrotron Light Source (LNLS), Campinas, Brazil. A quasi-monochromatic beam produced by a multilayer monochromator was used as an incident beam. The fluorescence photons were acquired with an energy dispersive HPGe detector (CANBERRA Industries Inc.) placed at 90? to the incident beam, while transmitted photons were detected with a fast Na(Tl) scintillation counter (CYBERSTAR Oxford Danfysik) placed behind the sample in the beam direction. All the tomographic images were reconstructed using a filtered-back projection algorithm.

  12. X-ray diagnostics for TFTR

    SciTech Connect

    von Goeler, S.; Hill, K.W.; Bitter, M.

    1982-12-01

    A short description of the x-ray diagnostic preparation for the TFTR tokamak is given. The x-ray equipment consists of the limiter x-ray monitoring system, the soft x-ray pulse-height-analysis-system, the soft x-ray imaging system and the x-ray crystal spectrometer. Particular attention is given to the radiation protection of the x-ray systems from the neutron environment.

  13. X-ray irradiation induced degradation of cellulose nitrate

    Microsoft Academic Search

    F. M. F. Ng; K. N. Yu

    2006-01-01

    Energy-dispersive X-ray fluorescence (EDXRF) spectrometry was previously proposed to measure the thickness of the cellulose nitrate layer of the commonly used LR 115 solid-state nuclear track detector (SSNTD). The present work is devoted to the investigation whether the X-ray radiation involved in EDXRF spectrometry will induce degradation of the cellulose nitrate. For this purpose, Fourier transform infrared (FTIR) spectroscopy was

  14. Multispectral glancing incidence X-ray telescope

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B. (Inventor)

    1990-01-01

    A multispectral glancing incidence X-ray telescope is illustrated capable of broadband, high-resolution imaging of solar and stellar X-ray and extreme ultraviolet radiation sources which includes a primary optical system preferably of the Wolter I type having a primary mirror system (20, 22). The primary optical system further includes an optical axis (24) having a primary focus (F1) at which the incoming radiation is focused by the primary mirrors. A plurality of ellipsoidal mirrors (30a, 30b, 30cand 30d) are carried at an inclination to the optical axis behind the primary focus (F1). A rotating carrier (32) is provided on which the ellipsoidal mirrors are carried so that a desired one of the ellipsoidal mirrors may be selectively positioned in front of the incoming radiation beam (26). In the preferred embodiment, each of the ellipsoidal mirrors has an identical concave surface carrying a layered synthetic microstructure coating tailored to reflect a desired wavelength of 1.5 .ANG. or longer. Each of the identical ellipsoidal mirrors has a second focus (F2) at which a detector (16) is carried. Thus the different wavelength image is focused upon the detector irregardless of which mirror is positioned in front of the radiation beam. In this manner, a plurality of low wavelengths in a wavelength band generally less than 30 angstroms can be imaged with a high resolution.

  15. X-ray based extensometry

    NASA Technical Reports Server (NTRS)

    Jordan, E. H.; Pease, D. M.

    1988-01-01

    A totally new method of extensometry using an X-ray beam was proposed. The intent of the method is to provide a non-contacting technique that is immune to problems associated with density variations in gaseous environments that plague optical methods. X-rays are virtually unrefractable even by solids. The new method utilizes X-ray induced X-ray fluorescence or X-ray induced optical fluorescence of targets that have melting temperatures of over 3000 F. Many different variations of the basic approaches are possible. In the year completed, preliminary experiments were completed which strongly suggest that the method is feasible. The X-ray induced optical fluorescence method appears to be limited to temperatures below roughly 1600 F because of the overwhelming thermal optical radiation. The X-ray induced X-ray fluorescence scheme appears feasible up to very high temperatures. In this system there will be an unknown tradeoff between frequency response, cost, and accuracy. The exact tradeoff can only be estimated. It appears that for thermomechanical tests with cycle times on the order of minutes a very reasonable system may be feasible. The intended applications involve very high temperatures in both materials testing and monitoring component testing. Gas turbine engines, rocket engines, and hypersonic vehicles (NASP) all involve measurement needs that could partially be met by the proposed technology.

  16. X-Ray Exam: Ankle

    MedlinePLUS

    What It Is An ankle X-ray is a safe and painless test that uses a small amount of radiation to make an image of the ankle. ... back part of the foot (tarsal bones). An X-ray machine sends a beam of radiation through ...

  17. Analysis of particles produced during airbag deployment by scanning electron microscopy with energy dispersive x-ray spectroscopy and their deposition on surrounding surfaces: a mid-research summary

    NASA Astrophysics Data System (ADS)

    Wyatt, J. Matney

    2011-06-01

    Airbags can be encountered in forensic work when investigating a car crash and are typically constructed with primerlike material to begin the deployment apparatus. The mechanisms of airbag deployment can produce particles ideal for scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) analysis. A recent study published by Berk studied airbags with vents and showed that it is possible for particles generated from the deployment of these airbags to deposit on surfaces in the vehicle as the airbags deflate.1 Another paper published by Berk reported particles similar in morphology and composition to primer gunshot residue (GSR) are produced by side impact airbags.2 This paper's aim will be to show mid-point results of a study still in progress in which non-vented airbags were analyzed to determine if they exhibited the same particle depositing features as their vented airbag counterparts. Further investigation in this study is being performed to find more airbags which produce primer gunshot residue-like particles containing lead, barium, and antimony from airbag deployment. To date, the study has resulted in (1) non-vented airbags exhibiting deposition of particles suitable for SEM/EDS analysis and (2) no gunshot residue-like particles being detected from the airbag residues studied thus far.

  18. P-V-T equation of state of molybdenite (MoS2) by a diamond anvil cell and in situ synchrotron angle-dispersive X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Fan, Dawei; Xu, Jingui; Ma, Maining; Liu, Jing; Xie, Hongsen

    2014-10-01

    The pressure-volume-temperature (P-V-T) equation of state (EoS) of a natural molybdenite (MoS2) has been measured at high temperature up to 700 K and high pressures up to 18.26 GPa, by using in situ angle-dispersive X-ray diffraction and diamond anvil cell. Analysis of room-temperature P-V data to a third-order Birch-Murnaghan EoS yields: V0=107.0±0.1 Å3, K0=67±2 GPa and K?0=5.0±0.3. With K?0 fixed to 4.0, we obtained: V0=106.7±0.1 Å3 and K0=74.5±0.8 GPa. Fitting of our P-V-T data by means of the high-temperature third order Birch-Murnaghan equations of state, gives the thermoelastic parameters: V0=107.0±0.1 Å3, K0=69±2 GPa, K?0=4.7±0.2, (?K/?T)P=-0.021±0.003 GPa K-1, a=(2.2±0.7)×10-5 K-1 and b=(2.9±0.8)×10-8 K-2. The temperature derivative of the bulk modulus and thermal expansion coefficient of MoS2 are obtained for the first time. Present results are also compared with previously studies determined the elastic properties of MoS2 and WS2.

  19. Field-emission scanning electron microscopy and energy-dispersive x-ray analysis to understand the role of tannin-based dyes in the degradation of historical wool textiles.

    PubMed

    Restivo, Annalaura; Degano, Ilaria; Ribechini, Erika; Pérez-Arantegui, Josefina; Colombini, Maria Perla

    2014-10-01

    An innovative approach, combining field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy (EDX) analysis, is presented to investigate the degradation mechanisms affecting tannin-dyed wool. In fact, tannin-dyed textiles are more sensitive to degradation then those dyed with other dyestuffs, even in the same conservation conditions. FESEM-EDX was first used to study a set of 48 wool specimens (artificially aged) dyed with several raw materials and mordants, and prepared according to historical dyeing recipes. EDX analysis was performed on the surface of wool threads and on their cross-sections. In addition, in order to validate the model formulated by the analysis of reference materials, several samples collected from historical and archaeological textiles were subjected to FESEM-EDX analysis. FESEM-EDX investigations enabled us to reveal the correlation between elemental composition and morphological changes. In addition, aging processes were clarified by studying changes in the elemental composition of wool from the protective cuticle to the fiber core in cross-sections. Morphological and elemental analysis of wool specimens and of archaeological and historical textiles showed that the presence of tannins increases wool damage, primarily by causing a sulfur decrease and fiber oxidation. PMID:24983911

  20. Determination of trace amounts of hexavalent chromium in drinking waters by dispersive microsolid-phase extraction using modified multiwalled carbon nanotubes combined with total reflection X-ray fluorescence spectrometry

    NASA Astrophysics Data System (ADS)

    Bahadir, Z.; Bulut, V. N.; Hidalgo, M.; Soylak, M.; Marguí, E.

    2015-05-01

    A methodology based on the combination of dispersive microsolid-phase extraction (DMSPE) with total reflection X-ray fluorescence (TXRF) spectrometry is proposed for the determination of hexavalent chromium in drinking waters. Multiwalled carbon nanotubes (MWCNTs) modified with the anionic exchanger tricaprylmethylammonium chloride (Aliquat 336) were used as solid sorbents. After the sorption process of Cr(VI) on the modified MWCNTs, the aqueous sample was separated by centrifugation and the loaded MWCNTs were suspended using a small volume of an internal standard solution and analyzed directly by a benchtop TXRF spectrometer, without any elution step. Parameters affecting the extraction process (pH and volume of the aqueous sample, amount of MWCNTs, extraction time) and TXRF analysis (volume of internal standard, volume of deposited suspension on the reflector, drying mode, and instrumental parameters) have been carefully evaluated to test the real capability of the developed methodology for the determination of Cr(VI) at trace levels. Using the best analytical conditions, it was found that the minimum Cr(VI) content that can be detected in an aqueous solution was 3 ?g L- 1. This value is almost 20 times lower than the maximum hexavalent chromium content permissible in drinking waters, according to the World Health Organization (WHO). Recoveries for spiked tap and mineral water samples were, in most cases, in the range of 101-108% which demonstrates the suitability of the TXRF methodology for monitoring Cr(VI) at trace levels in drinking water samples.

  1. High-energy polarized-beam energy-dispersive X-ray fluorescence analysis combined with activated thin layers for cadmium determination at trace levels in complex environmental liquid samples.

    PubMed

    Marguí, Eva; Fontàs, Clàudia; Van Meel, Katleen; Van Grieken, René; Queralt, Ignasi; Hidalgo, Manuela

    2008-04-01

    In this paper, we describe a new method for trace level Cd determination in complex environmental liquid samples. Thin layers activated with the extractant Aliquat 336 were prepared either by direct impregnation of commercial polymeric supports or by physical inclusion in a cellulose triacetate matrix, and both were effectively used to collect Cd present at low concentration in different aqueous matrixes. Quantitation of Cd contained in the thin layers was performed by high-energy polarized-beam energy-dispersive X-ray fluorescence. The effects of various experimental parameters such as layer composition, equilibration time, and instrumental conditions have been investigated. The analysis of different impregnated layers contacted with solutions ranging from 5 to 8000 microg L-1 Cd showed a linear response between the Cd concentration in the aqueous solutions and the metal present in the thin layer, with a detection limit of 0.7 microg L-1. The accuracy of the proposed method was confirmed by analyzing spiked seawater samples and a synthetic water sample containing, besides Cd, high amounts of other metal pollutants such as Ni, Cu, and Pb. The attained results were comparable to those obtained by anodic stripping voltammetry or inductively coupled plasma spectrometry. PMID:18327919

  2. Results of X-ray and optical monitoring of SCO X-1

    NASA Technical Reports Server (NTRS)

    Mook, D. E.; Messina, R. J.; Hiltner, W. A.; Belian, R.; Conner, J.; Evans, W. D.; Strong, I.; Blanco, V.; Hesser, J.; Kunkel, W.

    1974-01-01

    Sco X-1 was monitored at optical and X-ray wavelengths from 1970 April 26 to 1970 May 21. The optical observations were made at six observatories around the world and the X-ray observations were made by the Vela satellites. There was a tendency for the object to show greater variability in X-ray when the object is optically bright. A discussion of the intensity histograms is presented for both the optical and X-ray observations. No evidence for optical or X-ray periodicity was detected.

  3. Current research activities in the field of multilayers for soft X-rays in Research Institute for Scientific Measurements, Tohoku University, Sendai 980, Japan

    E-print Network

    Paris-Sud XI, Université de

    . Studies of multilayers in Japan are relatively new in the field of soft X-ray optics, in striking contrast, who is interested in developing X-ray microscopes and X-ray lithography devices for wavelengths of 101711 Current research activities in the field of multilayers for soft X-rays in Japan T. Namioka

  4. X-Ray Diffraction Apparatus

    NASA Technical Reports Server (NTRS)

    Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

    1996-01-01

    An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

  5. X-ray shearing interferometer

    DOEpatents

    Koch, Jeffrey A. (Livermore, CA)

    2003-07-08

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

  6. Dynamical X-ray focusing under conditions of X-ray acoustic resonance: II. Focusing in an elastically bent crystal

    SciTech Connect

    Nosik, V.L. [Russian Academy of Sciences, Moscow (Russian Federation)

    1994-12-31

    A systematic study is performed of dynamical diffraction focusing of X-rays in a bent vibrating crystal under conditions of X-ray acoustic resonance. In the classical description of diffraction scattering, ray trajectories repeat the shape of the dispersion surface. The positions of the focus points in a crystal are determined as functions of the magnitude of ultrasound amplitude, the deviation from resonance conditions, and specific features of crystal deformation. 23 refs., 6 figs.

  7. Milli X-ray fluorescence X-ray spectrum imaging for measuring potassium ion intrusion into concrete samples

    Microsoft Academic Search

    Jeffrey M. Davis; Dale E. Newbury; Prasada rao Rangaraju; Senthil Soundrapanian; Colin Giebson

    2009-01-01

    Of particular interest when studying the effects of deicing solutions on concrete is the depth of penetration of ions from deicing salts. To determine the limits of positive ion infiltration, a method based on milli X-ray fluorescence (mXRF) has been developed. This method combines traditional energy dispersive spectrometry (EDS) with stage movement X-ray mapping to analyze comparatively large areas of

  8. Atomic inner-shell X-ray laser at 1.46 nanometres pumped by an X-ray free-electron laser.

    PubMed

    Rohringer, Nina; Ryan, Duncan; London, Richard A; Purvis, Michael; Albert, Felicie; Dunn, James; Bozek, John D; Bostedt, Christoph; Graf, Alexander; Hill, Randal; Hau-Riege, Stefan P; Rocca, Jorge J

    2012-01-26

    Since the invention of the laser more than 50 years ago, scientists have striven to achieve amplification on atomic transitions of increasingly shorter wavelength. The introduction of X-ray free-electron lasers makes it possible to pump new atomic X-ray lasers with ultrashort pulse duration, extreme spectral brightness and full temporal coherence. Here we describe the implementation of an X-ray laser in the kiloelectronvolt energy regime, based on atomic population inversion and driven by rapid K-shell photo-ionization using pulses from an X-ray free-electron laser. We established a population inversion of the K? transition in singly ionized neon at 1.46 nanometres (corresponding to a photon energy of 849 electronvolts) in an elongated plasma column created by irradiation of a gas medium. We observed strong amplified spontaneous emission from the end of the excited plasma. This resulted in femtosecond-duration, high-intensity X-ray pulses of much shorter wavelength and greater brilliance than achieved with previous atomic X-ray lasers. Moreover, this scheme provides greatly increased wavelength stability, monochromaticity and improved temporal coherence by comparison with present-day X-ray free-electron lasers. The atomic X-ray lasers realized here may be useful for high-resolution spectroscopy and nonlinear X-ray studies. PMID:22281598

  9. Simultaneous wavelength conversion of ASK and DPSK signals based on four-wave-mixing in dispersion engineered silicon waveguides.

    PubMed

    Xu, Lin; Ophir, Noam; Menard, Michael; Lau, Ryan Kin Wah; Turner-Foster, Amy C; Foster, Mark A; Lipson, Michal; Gaeta, Alexander L; Bergman, Keren

    2011-06-20

    We experimentally demonstrate four-wave-mixing (FWM)-based continuous wavelength conversion of optical differential-phase-shift-keyed (DPSK) signals with large wavelength conversion ranges as well as simultaneous wavelength conversion of dual-wavelength channels with mixed modulation formats in 1.1-cm-long dispersion-engineered silicon waveguides. We first validate up to 100-nm wavelength conversion range for 10-Gb/s DPSK signals, showcasing the capability to perform phase-preserving operations at high bit rates in chip-scale devices over wide conversion ranges. We further validate the wavelength conversion of dual-wavelength channels modulated with 10-Gb/s packetized phase-shift-keyed (PSK) and amplitude-shift-keyed (ASK) signals; demonstrate simultaneous operation on multiple channels with mixed formats in chip-scale devices. For both configurations, we measure the spectral and temporal responses and evaluate the performances using bit-error-rate (BER) measurements. PMID:21716454

  10. X-ray Fluorescence (XRF) Assay Using Laser Compton Scattered (LCS) X-rays

    SciTech Connect

    Naeem, Syed F.; Chouffani, Khalid; Wells, Douglas P. [Idaho State University, Idaho Accelerator Center, Campus Box 8263, Pocatello ID 83209 (United States)

    2009-03-10

    Laser Compton Scattered (LCS) X-rays are produced as a result of the interaction between accelerated electrons and a laser beam. The yield of LCS X-rays is dependent on the laser power, angle of collision between interacting particles, and the electron linear accelerator's (linac) electron beam energy and its current. One of our research goals at the Idaho Accelerator Center (IAC) focuses on applications such as detection and imaging of fissionable isotopes for nuclear non-proliferation, safeguards and homeland security. Quasi monochromatic LCS X-rays offer much better signal-to-noise ratios for such applications. The energy of LCS X-rays is tunable, that enable element-specific analysis. Two sharp 36.5 keV and 98.4 keV LCS peaks were observed in two separate experiments based on electron beams tuned at 32 MeV and 37 MeV, that were brought in collision with the (Power){sub peak} = 4 GW Nd.YAG laser operating at 532 nm and 266 nm wavelengths. The linac was operating at 60 Hz with an electron beam pulse length of about 50 ps and a peak current of about 7 A. We exploited X-ray fluorescence (XRF) techniques to identify elemental K{alpha}{sub 1}, K{alpha}{sub 2}, and K{beta}{sub 1} lines in a high-purity germanium (HPGe) detector, with a 0.5 mm thick Beryllium (Be) absorbing layer, emitted from tin (Sn), cadmium (Cd), silver (Ag), gold (Au), and lead (Pb) foils with thicknesses ranging from 25-500 {mu}m, following absorption of 36.1 keV and 98.4 keV LCS X-rays. These reference foils were used for the proof of principle, and some have atomic numbers near to that of relevant fission products.

  11. X-ray Fluorescence (XRF) Assay Using Laser Compton Scattered (LCS) X-rays

    NASA Astrophysics Data System (ADS)

    Naeem, Syed F.; Chouffani, Khalid; Wells, Douglas P.

    2009-03-01

    Laser Compton Scattered (LCS) X-rays are produced as a result of the interaction between accelerated electrons and a laser beam. The yield of LCS X-rays is dependent on the laser power, angle of collision between interacting particles, and the electron linear accelerator's (linac) electron beam energy and its current. One of our research goals at the Idaho Accelerator Center (IAC) focuses on applications such as detection and imaging of fissionable isotopes for nuclear non-proliferation, safeguards and homeland security. Quasi monochromatic LCS X-rays offer much better signal-to-noise ratios for such applications. The energy of LCS X-rays is tunable, that enable element-specific analysis. Two sharp 36.5 keV and 98.4 keV LCS peaks were observed in two separate experiments based on electron beams tuned at 32 MeV and 37 MeV, that were brought in collision with the (Power)peak = 4 GW Nd.YAG laser operating at 532 nm and 266 nm wavelengths. The linac was operating at 60 Hz with an electron beam pulse length of about 50 ps and a peak current of about 7 A. We exploited X-ray fluorescence (XRF) techniques to identify elemental K?1, K?2, and K?1 lines in a high-purity germanium (HPGe) detector, with a 0.5 mm thick Beryllium (Be) absorbing layer, emitted from tin (Sn), cadmium (Cd), silver (Ag), gold (Au), and lead (Pb) foils with thicknesses ranging from 25-500 ?m, following absorption of 36.1 keV and 98.4 keV LCS X-rays. These reference foils were used for the proof of principle, and some have atomic numbers near to that of relevant fission products.

  12. Compositional Studies of InGaN Epilayers and Magnesium-doped GaN Grown by MOVPE, Using Wavelength Dispersive X-ray Spectrometry

    E-print Network

    Strathclyde, University of

    Aveiro, 3810-193 Aveiro, Portugal Introduction Indium gallium nitride (InxGa1-xN) alloys and p-type magnesium-doped GaN (Mg:GaN) form essential functional layers in III-nitride optoelectronic devices[1

  13. Engineered coherent soft-X-ray spectra for generating ultrashort soft-X-ray pulses

    Microsoft Academic Search

    C. Winterfeldt; Paulus A; T. Pfeifer; Sokollik T; R. Spitzenpfeil; D. Walter; G. Gerber; C. Spielmann

    2005-01-01

    Using adaptive pulse shaping of the driving 800 nm laser pulse, we demonstrate for the first time the complete control over the XUV spectrum of high harmonics. We are able to generate arbitrarily shaped spectra of coherent soft X-ray radiation in a gas-filled hollow fiber. We achieve both the enhancement and suppression of high-harmonic emission in a selected wavelength region

  14. High-energy X-ray detection by hafnium-doped organic-inorganic hybrid scintillators prepared by sol-gel method

    SciTech Connect

    Sun, Yan; Koshimizu, Masanori, E-mail: koshi@qpc.che.tohoku.ac.jp; Yahaba, Natsuna; Asai, Keisuke [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Nishikido, Fumihiko [Molecular Imaging Center, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba 263-8555 (Japan); Kishimoto, Shunji [Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Haruki, Rie [Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirane, Shirakata, Tokai, Ibaraki 319-1195 (Japan)

    2014-04-28

    With the aim of enhancing the efficiency with which plastic scintillators detect high-energy X-rays, hafnium-doped organic-inorganic hybrid scintillators were fabricated via a sol-gel method. Transmission electron microscopy of sampled material reveals the presence of Hf{sub x}Si{sub 1?x}O{sub 2} nanoparticles, dispersed in a polymer matrix that constitutes the active material of the X-ray detector. With Hf{sub x}Si{sub 1?x}O{sub 2} nanoparticles incorporated in the polymer matrix, the absorption edge and the luminescence wavelength is shifted, which we attribute to Mie scattering. The detection efficiency for 67.4-keV X-rays in a 0.6-mm-thick piece of this material is two times better than the same thickness of a commercial plastic scintillator-NE142.

  15. Normal incidence X-ray mirror for chemical microanalysis

    DOEpatents

    Carr, Martin J. (Tijeras, NM); Romig, Jr., Alton D. (Albuquerque, NM)

    1990-01-01

    A non-planar, focusing mirror, to be utilized in both electron column instruments and micro-x-ray fluorescence instruments for performing chemical microanalysis on a sample, comprises a concave, generally spherical base substrate and a predetermined number of alternating layers of high atomic number material and low atomic number material contiguously formed on the base substrate. The thickness of each layer is an integral multiple of the wavelength being reflected and may vary non-uniformly according to a predetermined design. The chemical analytical instruments in which the mirror is used also include a predetermined energy source for directing energy onto the sample and a detector for receiving and detecting the x-rays emitted from the sample; the non-planar mirror is located between the sample and detector and collects the x-rays emitted from the sample at a large solid angle and focuses the collected x-rays to the sample. For electron column instruments, the wavelengths of interest lie above 1.5 nm, while for x-ray fluorescence instruments, the range of interest is below 0.2 nm. Also, x-ray fluorescence instruments include an additional non-planar focusing mirror, formed in the same manner as the previously described m The invention described herein was made in the performance of work under contract with the Department of Energy, Contract No. DE-AC04-76DP00789, and the United States Government has rights in the invention pursuant to this contract.

  16. X-Ray photonics: X-rays inspire electron movies

    NASA Astrophysics Data System (ADS)

    Vrakking, Marc J. J.; Elsaesser, Thomas

    2012-10-01

    The advent of high-energy, short-pulse X-ray sources based on free-electron lasers, laser plasmas and high-harmonic generation is now making it possible to probe the dynamics of electrons within molecules.

  17. BAX: A dedicated X-Rays galaxy clusters Database

    E-print Network

    R. Sadat; A. Blanchard; C. Mendiboure

    2003-02-11

    We present BAX, Base de Donn\\'ees amas de galaxies X (http://webast.ast.obs-mip.fr/bax), a project aiming at building a comprehensive database dedicated to X-rays clusters of galaxies allowing detailed information retrieval. BAX provides the user with {\\it basic data} published in the literature on X-rays clusters of galaxies as well as with information concerning the physical properties in the X-rays domain or at other wavelengths. BAX allows individual studies on selected clusters as well as building up homogenous samples, from known X-rays clusters for which selection criteria are chosen through web interfaces. We expect BAX to become a useful tool for astronomy community in order to optimize the cluster science return using data from both ground based facilities like MEGACAM (CFHT), VIRMOS (VLT) and space missions like XMM, Chandra and Planck.

  18. NSLS-II X-Ray Diagnostics Development

    SciTech Connect

    ILINSKI, P.

    2011-03-28

    NSLS-II x-ray diagnostics will provide continuous online data of electron beam dimensions, which will be used to derive electron beam emittance and energy spread. It will also provide information of electron beam tilt for coupling evaluation. X-ray diagnostics will be based on imaging of bending magnet and three-pole wiggler synchrotron radiation sources. Diagnostics from three-pole wiggler source will be used to derive particles energy spread. Beta and dispersion functions will have to be evaluated for emittance and particles energy spread calculations. Due to small vertical source sizes imaging need to be performed in x-ray energy range. X-ray optics with high numerical aperture, such as compound refractive lens, will be used to achieve required spatial resolution. Optical setups with different magnifications in horizontal and vertical directions fill be employed to deal with large aspect ratio of the source. X-ray diagnostics setup will include x-ray imaging optics, monochromatization, x-ray imaging and recording components.

  19. A Study of Wavelength Calibration of NEWSIPS High-Dispersion Spectra

    E-print Network

    Myron A. Smith

    2001-04-03

    In this study we cross-correlate many IUE echellograms of a variety of stars to evaluate systematic error sources in the wavelength zeropoint of all three cameras. We first evaluated differences between the final archived ("NEWSIPS") and the originally processed ("IUESIPS") spectra. These show a clear time dependence in zeropoint for the SWP camera due to revisions in the IUESIPS wavelength scale. Small IUESIPS - NEWSIPS differences are also found for the LWR camera. We also examined wavelength zeropoint disparities between data obtained both through the small and large entrance apertures and for observations made by different target acquisition modes for faint and bright stars. We found that velocities resulting from these alternative observing modes are nil. For large-aperture observations the dominant error source is the target position placement in the aperture. We searched for spurious trends with time, and found only a suggestion of time trends for faint stars observed with the SWP camera. We also discovered 1-day, +/-3 km/s sinusoidsal patterns in intensive monitoring data which are ascribable to changes in telescope focus resulting from thermal drifts. In the second part of the paper, we measured mean zeropoint errors of NEWSIPS echellogram data against laboratory results by using the GHRS spectral atlas of the 10 Lac. We find that the derived apparent velocity difference for this star is -1 +/-3.5 km/s. Several less precise comparisons lead to similar results. The zeropoints of the NEWSIPS-processed LWP/LWR cameras are evaluated and are also found to be nearly zero (+/-5 km/s) relative to HST atlases of Arcturus and Procyon atlas. These results do not support result by Gonzalez-Riestra et al. that corrections should be introduced to the wavelength scales of various NEWSIPS high-dispersion data products.

  20. X-raying the Intergalactic OVI Absorbers

    E-print Network

    Y. Yao; T. M. Tripp; Q. D. Wang; C. W. Danforth; C. R. Canizares; J. M. Shull; H. L. Marshall; L. Song

    2009-03-23

    The observed intergalactic OVI absorbers at z>0 have been regarded as a significant reservoir of the ``missing baryons''. However, to fully understand how these absorbers contribute to the baryon inventory, it is crucial to determine whether the systems are collisionally ionized or photoionized (or both). Using the identified intergalactic OVI absorbers as tracers, we search for the corresponding X-ray absorption lines, which are useful for finding the missing baryons and for revealing the nature of the OVI absorbers. Stacking the Chandra grating spectra along six AGN sight lines, we obtain three spectra with signal-to-noise ratios of 32, 28, and 10 per 12.5 mA spectral bin around the expected OVII Kalpha wavelength. These spectra correspond to OVI absorbers with various dynamic properties. We find no detectable NeIX, OVII, OVIII, NVII, or CVI absorption lines in the spectra, but the high counting statistics allows us to obtain firm upper limits on the corresponding ionic column densities (in particular N(OVII)<=10 N(OVI) on average at the 95% confidence level). Jointly analyzing these non-detected X-ray lines with the averaged OVI column density, we further limit the average temperature of the OVI-bearing gas to be log[T(K)]<=5.7 in collisional ionization equilibrium. We discuss the implications of these results for physical properties of the putative warm-hot intergalactic medium and its detection in future X-ray observations.

  1. X-Ray Imaging System

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The FluoroScan Imaging System is a high resolution, low radiation device for viewing stationary or moving objects. It resulted from NASA technology developed for x-ray astronomy and Goddard application to a low intensity x-ray imaging scope. FlouroScan Imaging Systems, Inc, (formerly HealthMate, Inc.), a NASA licensee, further refined the FluoroScan System. It is used for examining fractures, placement of catheters, and in veterinary medicine. Its major components include an x-ray generator, scintillator, visible light image intensifier and video display. It is small, light and maneuverable.

  2. X-Ray Diffraction Microscopy

    NASA Astrophysics Data System (ADS)

    Thibault, Pierre; Elser, Veit

    2010-04-01

    X-ray diffraction phenomena have been used for decades to study matter at the nanometer and subnanometer scales. X-ray diffraction microscopy uses the far-field scattering of coherent X-rays to form the 2D or 3D image of a scattering object in a way that resembles crystallography. In this review, we describe the main principles, benefits, and limitations of diffraction microscopy. After sampling some of the milestones of this young technique and its close variants, we conclude with a short assessment of the current state of the field.

  3. A High Efficiency Grazing Incidence Pumped X-ray Laser

    SciTech Connect

    Dunn, J; Keenan, R; Price, D F; Patel, P K; Smith, R F; Shlyaptsev, V N

    2006-08-31

    The main objective of the project is to demonstrate a proof-of-principle, new type of high efficiency, short wavelength x-ray laser source that will operate at unprecedented high repetition rates (10Hz) that could be scaled to 1kHz or higher. The development of a high average power, tabletop x-ray laser would serve to complement the wavelength range of 3rd and future 4th generation light sources, e.g. the LCLS, being developed by DOE-Basic Energy Sciences. The latter are large, expensive, central, synchrotron-based facilities while the tabletop x-ray laser is compact, high-power laser-driven, and relatively inexpensive. The demonstration of such a unique, ultra-fast source would allow us to attract funding from DOE-BES, NSF and other agencies to pursue probing of diverse materials undergoing ultrafast changes. Secondly, this capability would have a profound impact on the semiconductor industry since a coherent x-ray laser source would be ideal for ''at wavelength'' {approx}13 nm metrology and microscopy of optics and masks used in EUV lithography. The project has major technical challenges. We will perform grazing-incidence pumped laser-plasma experiments in flat or groove targets which are required to improve the pumping efficiency by ten times. Plasma density characterization using our existing unique picosecond x-ray laser interferometry of laser-irradiated targets is necessary. Simulations of optical laser propagation as well as x-ray laser production and propagation through freely expanding and confined plasma geometries are essential. The research would be conducted using the Physics Directorate Callisto and COMET high power lasers. At the end of the project, we expect to have a high-efficiency x-ray laser scheme operating below 20 nm at 10Hz with a pulse duration of {approx}2 ps. This will represent the state-of-the-art in x-ray lasers and would be a major step forward from our present picosecond laser-driven x-ray lasers. There is an added bonus of creating the shortest wavelength laboratory x-ray laser, below 4.5 nm and operating in the water window, by using the high-energy capability of the Titan laser.

  4. Surface-Enhanced X-Ray Fluorescence

    NASA Technical Reports Server (NTRS)

    Anderson, Mark

    2010-01-01

    Surface-enhanced x-ray fluorescence (SEn-XRF) spectroscopy is a form of surface- enhanced spectroscopy that was conceived as a means of obtaining greater sensitivity in x-ray fluorescence (XRF) spectroscopy. As such, SEn-XRF spectroscopy joins the ranks of such other, longer-wavelength surface-enhanced spectroscopies as those based on surface-enhanced Raman scattering (SERS), surface-enhanced resonance Raman scattering (SERRS), and surfaceenhanced infrared Raman absorption (SEIRA), which have been described in previous NASA Tech Briefs articles. XRF spectroscopy has been used in analytical chemistry for determining the elemental compositions of small samples. XRF spectroscopy is rapid and quantitative and has been applied to a variety of metal and mineralogical samples. The main drawback of XRF spectroscopy as practiced heretofore is that sensitivity has not been as high as required for some applications. In SEn-XRF as in the other surface-enhanced spectroscopies, one exploits several interacting near-field phenomena, occurring on nanotextured surfaces, that give rise to local concentrations of incident far-field illumination. In this case, the far-field illumination comes from an x-ray source. Depending on the chemical composition and the geometry of a given nanotextured surface, these phenomena could include the lightning-rod effect (concentration of electric fields at the sharpest points on needlelike surface features), surface plasmon resonances, and grazing incidence geometric effects. In the far field, the observable effect of these phenomena is an increase in the intensity of the spectrum of interest - in this case, the x-ray fluorescence spectrum of chemical elements of interest that may be present within a surface layer at distances no more than a few nanometers from the surface.

  5. High-resolution hard-X-ray fluorescence spectrometer

    NASA Astrophysics Data System (ADS)

    Kleimenov, Evgueni; Bergamaschi, Anna; van Bokhoven, Jeroen; Janousch, Markus; Schmitt, Bernd; Nachtegaal, Maarten

    2009-11-01

    A Johann-type X-ray fluorescence spectrometer for XES, RXES/RIXS, HERFD XAS and RXS experiments was designed, constructed and commissioned at the X10DA-SuperXAS beamline of the Swiss Light Source. The spectrometer consists of three key elements: a sample manipulator, an X-ray dispersive element (spherically bent silicon or germanium crystal), and an one-dimensional-array X-ray detector. The detected X-ray fluorescence energy is scanned by changing the angle between the sample, crystal and detector. The energy resolution of the spectrometer ranges from sub-eV to several eV. Thanks to the use of a one-dimensional array detector the spectrometer is easy to align and operate.

  6. Echo Tomography of Reprocessing Sites in X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Patterson, Joseph; Haswell, Carole

    1998-01-01

    We discovered correlated rapid variability between the optical/UV and X-ray emission for the first time in a soft X-ray transient, GRO J1655-40. Hubble Space Telescope light curves show features similar to those seen by the Rossi X-ray Timing Explorer, but with a mean delay of up to 10 - 20 s. We interpret the correlation as the result of reprocessing of X-rays into optical and UV emission, with a delay owing to finite light travel time; this assumption enables us to perform echo mapping of the system. The time-delay distribution has a mean of 14.6 +/-1.4 s and a dispersion of 10.5+/-1.9 s at binary phase 0.4. This establishes that the reprocessing region is the accretion disk around the compact star, rather than the mass-donating secondary. These results have been published.

  7. Miniature x-ray source

    DOEpatents

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

    2000-01-01

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

  8. X-rays and Cosmology

    E-print Network

    A. C. Fabian

    2000-01-11

    The role of X-ray observations for cosmological studies and conclusions is briefly explored. X-rays currently yield cosmologically interesting results on the abundances, evolution and gas content of clusters of galaxies, on the clustering and evolution of active galaxies and on the X-ray Background. They are unlikely in the long term future to give the most precise values of the cosmological parameters, although in the short term the baryon fraction of clusters and the Sunyaev-Zeldovich effect will remain important determinants and checks for some parameters. X-rays will however continue to play an important role in studying the astrophysics of the formation and growth of black holes, galaxies, groups and clusters. It is possible that this role will be crucial, if winds from active galaxies are responsible for breaking the simple gravitational scaling laws for clusters.

  9. Chiropractic x-ray rationale

    PubMed Central

    Sherman, Ray

    1986-01-01

    The use of x-ray is important to the chiropractic profession. The reasons for this significance are enumerated and discussed. The relevance of roentgenology to present and future chiropractic practice is set forth.

  10. Nanoscale X-ray imaging

    Microsoft Academic Search

    Anne Sakdinawat; David Attwood

    2010-01-01

    Recent years have seen significant progress in the field of soft- and hard-X-ray microscopy, both technically, through developments in source, optics and imaging methodologies, and also scientifically, through a wide range of applications. While an ever-growing community is pursuing the extensive applications of today's available X-ray tools, other groups are investigating improvements in techniques, including new optics, higher spatial resolutions,

  11. X-ray computed tomography

    NASA Astrophysics Data System (ADS)

    1993-05-01

    The primary advantage of the X-ray computed tomography (XRCT) NDE method is that features are not superposed in the image, thereby rendering them easier to interpret than radiographic projection images. Industrial XRCT systems, unlike medical diagnostic systems, have no size and dosage constraints; they are accordingly used for systems from the scale of gas turbine blades, with hundreds-of-kV energies, to those of the scale of ICBMs, requiring MV-level X-ray energies.

  12. 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.

  13. Conservation of Moroccan manuscript papers aged 150, 200 and 800 years. Analysis by infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), and scanning electron microscopy energy dispersive spectrometry (SEM-EDS).

    PubMed

    Hajji, Latifa; Boukir, Abdellatif; Assouik, Jamal; Lakhiari, Hamid; Kerbal, Abdelali; Doumenq, Pierre; Mille, Gilbert; De Carvalho, Maria Luisa

    2015-02-01

    The preservation of manuscripts and archive materials is a serious problem for librarians and restorers. Paper manuscript is subjected to numerous degradation factors affecting their conservation state. This research represents an attempt to evaluate the conservation restoration process applied in Moroccan libraries, especially the alkaline treatment for strengthening weakened paper. In this study, we focused on six samples of degraded and restored paper taken from three different Moroccan manuscripts aged 150, 200 and 800 years. In addition, the Japanese paper used in restoration has been characterized. A modern paper was also analyzed as reference. A three-step analytical methodology based on infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS) analysis was developed before and after restoration in order to determine the effect of the consolidation treatment on the paper structure. The results obtained by XRD and ATR-FTIR disclosed the presence of barium sulfate (BaSO4) in all restored paper manuscripts. The presence of calcium carbonate (CaCO3) in all considered samples was confirmed by FTIR spectroscopy. The application of de-acidification treatment causes significant changes connected with the increase of intensity mostly in the region 1426 cm(-1), assigned to the asymmetric and symmetric CO stretching mode of calcite, indicating the effectiveness of de-acidification procedure proved by the rise of the alkaline reserve content allowing the long term preservation of paper. Observations performed by SEM magnify the typical paper morphology and the structure of fibbers, highlighting the effect of the restoration process, manifested by the reduction of impurities. PMID:25459630

  14. Extragalactic X-ray sources

    SciTech Connect

    Pounds, K.A. (Leicester, University, Leicester, England); Fabian, A.C. (Cambridge University, Cambridge, England)

    1980-01-01

    Surveys of the extragalactic X-ray sky based on data obtained from the Uhuru and Ariel V satellites are considered. The X-ray luminosity function of clusters is discussed the total density of X-ray clusters is found to approach that of all Abell clusters at a luminosity of 10 to the 43rd ergs/sec. It is concluded that for cluster X-ray sources, the bulk of the X-rays below about 10 keV result from thermal bremsstrahlung, predominantly from the cores of the clusters the mass of gas in the core is only a few percent of the total core binding mass, and the X-ray data are consistent with an iron abundance in the hot gas which is about half the cosmic value. Attention is also given to the structure of the nearby rich clusters Perseus, Virgo and Coma, to variability in Seyfert X-radiation and to high-excitation narrow emission line galaxies.

  15. 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.

  16. High spectral and spatial resolution X-ray transmission radiography and tomography using a Color X-ray Camera

    PubMed Central

    Boone, Matthieu N.; Garrevoet, Jan; Tack, Pieter; Scharf, Oliver; Cormode, David P.; Van Loo, Denis; Pauwels, Elin; Dierick, Manuel; Vincze, Laszlo; Van Hoorebeke, Luc

    2013-01-01

    High resolution X-ray radiography and computed tomography are excellent techniques for non-destructive characterization of an object under investigation at a spatial resolution in the micrometer range. However, as the image contrast depends on both chemical composition and material density, no chemical information is obtained from this data. Furthermore, lab-based measurements are affected by the polychromatic X-ray beam, which results in beam hardening effects. New types of X-ray detectors which provide spectral information on the measured X-ray beam can help to overcome these limitations. In this paper, an energy dispersive CCD detector with high spectral resolution is characterized for use in high resolution radiography and tomography, where a focus is put on the experimental conditions and requirements of both measurement techniques. PMID:24357889

  17. Simultaneous dual-energy X-ray stereo imaging.

    PubMed

    Mokso, Rajmund; Oberta, Peter

    2015-07-01

    Dual-energy or K-edge imaging is used to enhance contrast between two or more materials in an object and is routinely realised by acquiring two separate X-ray images each at different X-ray wavelength. On a broadband synchrotron source an imaging system to acquire the two images simultaneously was realised. The single-shot approach allows dual-energy and stereo imaging to be applied to dynamic systems. Using a Laue-Bragg crystal splitting scheme, the X-ray beam was split into two and the two beam branches could be easily tuned to either the same or to two different wavelengths. Due to the crystals' mutual position, the two beam branches intercept each other under a non-zero angle and create a stereoscopic setup. PMID:26134814

  18. GOES-SXI views the Sun in X-rays (3 Channels)

    NSDL National Science Digital Library

    Tom Bridgman

    2003-01-30

    The Solar X-ray Imager (SXI) aboard GOES-12 went online for full-time operation on January 22, 2003. It provides full-disk X-ray images of the Sun updated every few minutes. This movie combines three channels from the imager with red covering 0.6-2.0 nanometers wavelength, green covering 0.6-4.0 nanometers wavelength, and blue covering ~0.6-6.0 nanometers wavelength.

  19. Wavelength Conversion Based on Raman and Non-Resonant Four-Wave Mixing in Silicon Nanowire Rings Without Dispersion Engineering

    Microsoft Academic Search

    Nathalie Vermeulen; John E. Sipe; Yannick Lefevre; Christof Debaes; Hugo Thienpont

    2011-01-01

    We propose an efficient wavelength conversion scheme that is based on either Raman-resonant four-wave mix- ing or non-resonant Kerr-induced four-wave mixing in a silicon nanowire ring, and that does not require dispersion engineering of the nanowire. We rely on the spatial variation of the Raman and Kerr susceptibilities around the ring to quasi-phase match the wavelength conversion processes for TE

  20. Femtosecond electronic response of atoms to ultra-intense X-rays

    Microsoft Academic Search

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

    2010-01-01

    An era of exploring the interactions of high-intensity, hard X-rays with matter has begun with the start-up of a hard-X-ray free-electron laser, the Linac Coherent Light Source (LCLS). Understanding how electrons in matter respond to ultra-intense X-ray radiation is essential for all applications. Here we reveal the nature of the electronic response in a free atom to unprecedented high-intensity, short-wavelength,

  1. A COMPARISON OF X-RAY AND MID-INFRARED SELECTION OF OBSCURED ACTIVE GALACTIC NUCLEI

    Microsoft Academic Search

    Megan E. Eckart; Fiona A. Harrison; Ian D. McGreer; David J. Helfand; Daniel Stern

    2010-01-01

    We compare the relative merits of active galactic nuclei (AGNs) selection at X-ray and mid-infrared wavelengths using data from moderately deep fields observed by both Chandra and Spitzer. The X-ray-selected AGN sample and associated photometric and spectroscopic optical follow-up are drawn from a subset of fields studied as part of the Serendipitous Extragalactic X-ray Source Identification (SEXSI) program. Mid-infrared data

  2. High Resolution Imaging of a Dense Microcapillary Plasma with a Tabletop Soft X-Ray Laser

    Microsoft Academic Search

    J. J. Rocca; M. C. Marconi; C. H. Moreno; C. D. Macchietto; V. N. Shlyaptsev

    1998-01-01

    We report the first use of a table-top soft x-ray laser in the imaging of dense plasmas. Due to their short wavelength, high brightness, short pulse duration and high degree of collimation, soft x-ray lasers are excellent radiation sources to perform shadowgraphy studies in dense plasmas. Recently, a Ne-like Y x-ray laser pumped by the Nova laser was used at

  3. The vacuum system of the European X-ray free electron laser XFEL

    Microsoft Academic Search

    K. Zapfe; M. Böhnert; O. Hensler; D. Hoppe; N. Mildner; B. Nagorny; K. Rehlich; H. Remde; A. Wagner; T. Wohlenberg; J. Wojtkiewicz

    2008-01-01

    The European X-ray Free Electron Laser XFEL, a new international research facility, will be built at DESY\\/Hamburg. The XFEL will generate extremely brilliant and ultra short pulses of spatially coherent X-rays with tuneable wavelengths down to 0.1 nm, and exploit them for revolutionary scientific experiments at various disciplines. The basic process adopted to produce the X-ray pulses is SASE (Self-Amplified

  4. Computed tomography of cryogenic biological specimens based on X-ray microscopic images

    Microsoft Academic Search

    D Weiß; G Schneider; B Niemann; P Guttmann; D Rudolph; G Schmahl

    2000-01-01

    Soft X-ray microscopy employs the photoelectric absorption contrast between water and protein in the 2.34–4.38nm wavelength region to visualize protein structures down to 30nm size without any staining methods. Due to the large depth of focus of the Fresnel zone plates used as X-ray objectives, computed tomography based on the X-ray microscopic images can be used to reconstruct the local

  5. Multispectral glancing incidence X-ray telescope

    NASA Technical Reports Server (NTRS)

    Hoover, R. B. (inventor)

    1986-01-01

    A multispectural glancing incidence X-ray telescope is illustrated capable of broadband, high-resolution imaging of solar and stellar X-ray and extreme ultraviolet radiation sources which includes a primary optical system preferably of the Wolter I type having a primary mirror system. The primary optical system further includes an optical axis having a primary focus at which the incoming radiation is focused by the primary mirrors. A plurality of ellipsoidal mirrors are carried at an inclination to the optical axis behind the primary focus. A rotating carrier is provided on which the ellipsoidal mirrors are carried so that a desired one of the ellipsoidal mirrors may be selectively positioned in front of the incoming radiation beam. In the preferred embodiment, each of the ellipsoidal mirrors has an identical concave surface carrying a layered synthetic microstructure coating tailored to reflect a desired wavelength of 1.5A or longer. Each of the identifical ellipsoidal mirrors has a second focus at which a detector is carried. Thus the different wavelength image is focused upon the detector irregardless of which mirror is positioned in front of the radiation beam.

  6. X-ray Free-electron Lasers

    SciTech Connect

    Pellegrini, Claudio [UCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547 (United States)

    2009-09-10

    We review the present status and properties of X-ray free-electron lasers in operation or under construction in the nanometer and sub-nanometer wavelength range, and the novel possibilities they offer for the study of atomic and molecular processes. We also discuss recent developments in relativistic electron beam physics that give us the possibility of designing a new generation of X-ray free-electron lasers that: a. are more compact; b. reduce the radiation pulse duration to one femtosecond or below; c. extend the photon energy to the 50 keV region. These results are obtained by reducing the electron bunch charge while at same time maximizing the beam brightness and reducing the bunch length to a value near or smaller than the free-electron laser cooperation length. In the last case the radiation pulse is fully coherent in the longitudinal and transverse space. The increase in beam brightness can also be used to reduce the beam energy needed for a given radiation wavelength, when, at the same time, the undulator period is reduced. The simultaneous decrease in beam energy and undulator period leads to a more compact free-electron laser, while the high beam brightness reduces the gain length and increases the coherent radiation intensity.

  7. Development of a Planetary X-Ray Fluorescence Spectrometer and Standard Samples for on-board Calibration

    NASA Astrophysics Data System (ADS)

    Dreißigacker, A.; Fabel, O.; Köhler, E.; van Gasselt, S.; Meyer, M.

    2014-04-01

    At the Planetary Sciences and Remote Sensing research group at Freie Universität Berlin an SCDbased X-Ray Fluorescence Spectrometer (XRF-X) is being developed to be employed on planetary orbiters. It performs direct, passive energy-dispersive X-ray fluorescence measurements of planetary surfaces by measuring the emitted X-ray fluorescence induced by solar X-rays and high-energy particles.

  8. Review of soft x-ray lasers and their applications

    SciTech Connect

    Skinner, C.H.

    1991-03-01

    The emerging technology of soft x-ray lasers is in a transition phase between the first laboratory demonstrations of gain and the acceptance of soft x-ray lasers as practical tools for novel applications. Current research is focused on several fronts. The operational wavelength range has been extended to the water window'', important for applications in the life sciences. Gain has also been generated with substantially simpler technology (such as a 6J laser) and this augurs well for the commercially availability in the near future of soft x-ray lasers for a variety of applications. Advanced soft x-ray laser concepts are being developed from investigations into ultra-high intensity laser/matter interactions. The first paper a brief historical perspective of x-ray microscopy and holography have begun. In this paper a brief historical perspective of x-ray laser development will be followed by a review of recent advances in recombination, collisional and photo-pumped systems and applications. A summary of current gain-length performance achieved in laboratories worldwide is presented. Near term prospects for applications to novel fields are discussed. 81 refs., 9 figs., 1 tab.

  9. X-Ray Detector: An x-ray radiation detector design code

    Microsoft Academic Search

    Rick B. Spielman

    1990-01-01

    X-Ray Detector (XRD) is an x-ray detector design code. It is intended to aid in the rapid design of x-ray detector packages. The design capabilities of XRD include filters, x-ray mirrors, x-ray diodes, silicon PIN diodes, GaAs PIN diodes, photoconducting detectors, bolometers, and x-ray film. XRD uses x-ray cross-section information stored in easily-modified external libraries. Interactive calculations are completed in

  10. Modeling the Radio to X-ray SED of Galaxies

    E-print Network

    L. Silva; G. L. Granato; A. Bressan; P. Panuzzo

    2002-08-17

    Our multi-wavelength model GRASIL for the SED of galaxies is described, in particular the recent extension to the radio and X-ray range. With our model we can study different aspects of galaxy evolution by exploiting all available spectral observations, where different emission components dominate.

  11. SOLAR X-RAY OBSERVATIONS BY INJUN 1

    Microsoft Academic Search

    J. A. Van Allen; L. A. Frank; B. Maehlum; L. W. Acton

    1965-01-01

    On the basis of 48 random observations of the sun from June through December 1961 with a thin mica window Geiger tube on satellite Injun 1, it is found that: (a) The 'quiet day' solar X-ray flux at I astronomical unit in the wavelength range X < 14 A had a minimum value of 0.5 X 10 -a erg (cmsec)

  12. X-ray polarimetry of AGN with XEUS

    Microsoft Academic Search

    D. Grupe; B. J. Wills

    2003-01-01

    The geometry of AGN can potentially be probed by polarimetry, either as a means of observing a hidden nucleus by scattered light, or by understanding the role of dust and gas in the central engine environment. Polarimetry studies of AGN are well-established in optical and radio wavelength ranges. However, due to the small number of photons available in X-ray observations,

  13. The Evolution of Coronal X-ray Emission

    E-print Network

    . The magnetic field is produced by an interaction between rotation, differential rotation and convective motions material from beneath. The Sun of course looks different at X-ray wavelengths. Loops of magnetic field constrain plasmas at millions of degrees. The footpoints of these loops cover at most a few percent

  14. X-ray characterization of solid small molecule organic materials

    SciTech Connect

    Billinge, Simon; Shankland, Kenneth; Shankland, Norman; Florence, Alastair

    2014-06-10

    The present invention provides, inter alia, methods of characterizing a small molecule organic material, e.g., a drug or a drug product. This method includes subjecting the solid small molecule organic material to x-ray total scattering analysis at a short wavelength, collecting data generated thereby, and mathematically transforming the data to provide a refined set of data.

  15. Condensed matter physics using a coherent X-ray source

    Microsoft Academic Search

    I. Lindau

    1997-01-01

    A tunable coherent light source providing X-rays at wavelengths down to 1 Å with high brilliance and femtosecond time-resolution would open up new and unprecedented research opportunities in condensed matter physics. Here we review a few of these opportunities and speculate on possible future developments.

  16. Imaging X-ray Thomson Scattering Spectrometer Design and Demonstration

    SciTech Connect

    Gamboa, E.J. [University of Michigan; Huntington, C.M. [University of Michigan; Trantham, M.R. [University of Michigan; Keiter, P.A [University of Michigan; Drake, R.P. [University of Michigan; Montgomery, David [Los Alamos National Laboratory; Benage, John F. [Los Alamos National Laboratory; Letzring, Samuel A. [Los Alamos National Laboratory

    2012-05-04

    In many laboratory astrophysics experiments, intense laser irradiation creates novel material conditions with large, one-dimensional gradients in the temperature, density, and ionization state. X-ray Thomson scattering is a powerful technique for measuring these plasma parameters. However, the scattered signal has previously been measured with little or no spatial resolution, which limits the ability to diagnose inhomogeneous plasmas. We report on the development of a new imaging x-ray Thomson spectrometer (IXTS) for the Omega laser facility. The diffraction of x-rays from a toroidally-curved crystal creates high-resolution images that are spatially resolved along a one-dimensional profile while spectrally dispersing the radiation. This focusing geometry allows for high brightness while localizing noise sources and improving the linearity of the dispersion. Preliminary results are presented from a scattering experiment that used the IXTS to measure the temperature profile of a shocked carbon foam.

  17. X-ray Emission from Massive Stars

    E-print Network

    Cohen, David

    X-ray Emission from Massive Stars David Cohen Department of Physics and Astronomy Swarthmore be related to the production of X-rays on massive stars. If so, massive stars' X-rays are much different than those found our own Sun and other cooler stars like the Sun that produce X-rays via magnetic activity

  18. High-intensity laser synchrotron x-ray source

    SciTech Connect

    Pogorelsky, I.V.

    1995-10-01

    A laser interacting with a relativistic electron beam behaves like a virtual wiggler of an extremely short period equal to half of the laser wavelength. This approach opens a route to relatively compact, high-brightness x-ray sources alternative or complementary to conventional synchrotron light sources. Although not new, the Laser Synchrotron Light Source (LSLS) concept is still waiting for a convincing demonstration. Available at the BNL`s Accelerator Test Facility (ATF), a high-brightness electron beam and the high-power C0{sub 2} laser may be used as prototype LSLS brick stones. In a feasible demonstration experiment, 10-GW, 100-ps C0{sub 2} laser beam will be brought to a head-on collision with a 10-ps, 0.5-nC, 70 MeV electron bunch. Flashes of well-collimated, up to 9.36-keV ({approximately}{Angstrom}) x-rays of 10-ps pulse duration, with a flux of {approximately}10{sup 19} photons/sec will be produced via linear Compton backscattering. The x-ray spectrum is tunable proportionally to a variable e-beam energy. A natural short-term extension of the proposed experiment would be further enhancement of the x-ray flux to a 10{sup 21}{minus}10{sup 22} photons/sec level, after the ongoing ATF CO{sub 2} laser upgrade to 1 TW peak power and electron bunch shortening to 3 ps. The ATF LSLS x-ray beamline, exceeding by orders of magnitude the peak fluxes attained at the National Synchrotron Light Source (NSLS) x-ray storage ring, may become attractive for certain users, e.g., for biological x-ray microscopy. In addition, a terawatt CO{sub 2} laser will enable harmonic multiplication of the x-ray spectrum via nonlinear Compton scattering.

  19. Three-dimensional manipulation of electron beam phase space for seeding soft x-ray free-electron lasers

    E-print Network

    Feng, Chao; Deng, Haixiao; Zhao, Zhentang

    2014-01-01

    In this letter, a simple technique is proposed to induce strong density modulation into the electron beam with small energy modulation. By using the combination of a transversely dispersed electron beam and a wave-front tilted seed laser, three-dimensional manipulation of the electron beam phase space can be utilized to significantly enhance the micro-bunching of seeded free-electron laser schemes, which will improve the performance and extend the short-wavelength range of a single-stage seeded free-electron laser. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in a soft x-ray free-electron laser.

  20. Compression of powerful x-ray pulses to attosecond durations by stimulated Raman backscattering in plasmas

    NASA Astrophysics Data System (ADS)

    Malkin, V. M.; Fisch, N. J.; Wurtele, J. S.

    2007-02-01

    Backward Raman amplification (BRA) in plasmas holds the potential for longitudinal compression and focusing of powerful x-ray pulses. In principle, this method is capable of producing pulse intensities close to the vacuum breakdown threshold by manipulating the output of planned x-ray sources. The minimum wavelength limit of BRA applicability to compression of laser pulses in plasmas is found.

  1. Compression of powerful x-ray pulses to attosecond durations by stimulated Raman backscattering in plasmas

    SciTech Connect

    Malkin, V. M.; Fisch, N. J.; Wurtele, J. S. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States); Lawrence Berkeley National Laboratory and Physics Department, University of California, Berkeley, California 94720 (United States)

    2007-02-15

    Backward Raman amplification (BRA) in plasmas holds the potential for longitudinal compression and focusing of powerful x-ray pulses. In principle, this method is capable of producing pulse intensities close to the vacuum breakdown threshold by manipulating the output of planned x-ray sources. The minimum wavelength limit of BRA applicability to compression of laser pulses in plasmas is found.

  2. X-ray Emission in Non-AGN Galaxies at z ~ 1

    E-print Network

    Chatterjee, Suchetana; Jeltema, Tesla; Myers, Adam D; Aird, James; Bundy, Kevin; Conselice, Christopher; Cooper, Michael; Laird, Elise; Nandra, Kirpal; Willmer, Christopher

    2015-01-01

    Using data from the DEEP2 galaxy redshift survey and the All Wavelength Extended Groth Strip International Survey we obtain stacked X-ray maps of galaxies at 0.7 1, we find no evidence that our results for X-ray scaling relations depend on optical color.

  3. Advanced mercuric iodide detectors for X-ray microanalysis.

    PubMed

    Warburton, W K; Iwanczyk, J S

    1987-01-01

    We first present a brief tutorial on Mercuric Iodide (HgI2) detectors and the intimately related topic of near-room temperature ultralow noise preamplifiers. This provides both a physical basis and technological perspective for the topics to follow. We next describe recent advances in HgI2 applications to x-ray microanalysis, including a space probe Scanning Electron Microscope (SEM), Synchrotron x-ray detectors, and energy dispersive detector arrays. As a result of this work, individual detectors can now operate stably for long periods in vacuum, detect soft x-rays to the oxygen K edge at 523 eV, or count at rates exceeding 2x10(5)/sec. The detector packages are small, lightweight, and use low power. Preliminary HgI2 detector arrays of 10 elements with 500eV resolution have also been constructed and operate stably. Finally, we discuss expected advances in HgI2 array technology, including improved resolution, vacuum operation, and the development of soft x-ray transparent encapsulants. Array capabilities include: large active areas, high (parallel) count rate capability and spatial sensitivity. We then consider areas of x-ray microanalysis where the application of such arrays would be advantageous, particularly including elemental microanalysis, via x-ray fluorescence spectroscopy, in both SEMs and in scanning x-ray microscopes. The necessity of high count rate capability as spatial resolution increases is given particular attention in this connection. Finally, we consider the possibility of Extended X-ray Absorption Fine Structure (EXAFS) studies on square micron sized areas, using detector arrays. PMID:3481104

  4. X-ray Studies of Galaxies

    NASA Technical Reports Server (NTRS)

    Brown, Beth A.

    2006-01-01

    I will give a brief history of X-ray astronomy, and discuss the current X-ray observatories and their discoveries. I will then focus on the discovery of X-rays from galaxies and galaxy clusters and why astronomers look at galaxies in X-rays (multiwavelength studies). Finally, I will discuss diffuse emission and X-ray source populations in normal (non-AGN) galaxies.

  5. Soft X-ray interferometry and holography

    Microsoft Academic Search

    S. Aoki; S. Kikuta

    1986-01-01

    Four types of soft X-ray interferometers are proposed, and two of them, Lloyd's mirror and Young's experiment are examined. Phase shifts of refracting objects are observed with these interferometers. Two types of X-ray holograms are taken. Gabor in-line X-ray holograms are recorded by using undulator radiation on X-ray resists. Two-dimensional lensless Fourier-transform X-ray holograms are recorded and reconstructed with visible

  6. X-ray sensitive video camera

    Microsoft Academic Search

    Randy Luhta; John A. Rowlands

    1993-01-01

    By converting the absorbed X-ray image directly to an electrical video signal, the x-ray sensitive video camera offers improved resolution and reduced veiling glare over a conventional x-ray image intensifier for medical fluoroscopy. Unfortunately, currently available x-ray sensitive video cameras are limited to a 1' field of view and poor quantum efficiency. We are developing an x-ray sensitive vidicon for

  7. The SWIRE/Chandra Survey: The X-ray Sources

    NASA Astrophysics Data System (ADS)

    Wilkes, Belinda J.; Kilgard, Roy; Kim, Dong-Woo; Kim, Minsun; Polletta, Mari; Lonsdale, Carol; Smith, Harding E.; Surace, Jason; Owen, Frazer N.; Franceschini, A.; Siana, Brian; Shupe, David

    2009-12-01

    We report a moderate-depth (70 ks), contiguous 0.7 deg2 Chandra survey in the Lockman Hole Field of the Spitzer/SWIRE Legacy Survey coincident with a completed, ultra-deep VLA survey with deep optical and near-infrared imaging in-hand. The primary motivation is to distinguish starburst galaxies and active galactic nuclei (AGNs), including the significant, highly obscured (log N H > 23) subset. Chandra has detected 775 X-ray sources to a limiting broadband (0.3-8 keV) flux ~4 × 10-16 erg cm-2 s-1. We present the X-ray catalog, fluxes, hardness ratios, and multi-wavelength fluxes. The log N versus log S agrees with those of previous surveys covering similar flux ranges. The Chandra and Spitzer flux limits are well matched: 771 (99%) of the X-ray sources have infrared (IR) or optical counterparts, and 333 have MIPS 24 ?m detections. There are four optical-only X-ray sources and four with no visible optical/IR counterpart. The very deep (~2.7 ?Jy rms) VLA data yield 251 (>4?) radio counterparts, 44% of the X-ray sources in the field. We confirm that the tendency for lower X-ray flux sources to be harder is primarily due to absorption. As expected, there is no correlation between observed IR and X-ray fluxes. Optically bright, type 1, and red AGNs lie in distinct regions of the IR versus X-ray flux plots, demonstrating the wide range of spectral energy distributions in this sample and providing the potential for classification/source selection. Many optically bright sources, which lie outside the AGN region in the optical versus X-ray plots (fr /fx >10), lie inside the region predicted for red AGNs in IR versus X-ray plots, consistent with the presence of an active nucleus. More than 40% of the X-ray sources in the VLA field are radio-loud using the classical definition, RL . The majority of these are red and relatively faint in the optical so that the use of RL to select those AGNs with the strongest radio emission becomes questionable. Using the 24 ?m to radio flux ratio (q 24) instead results in 13 of the 147 AGNs with sufficient data being classified as radio-loud, in good agreement with the ~10% expected for broad-lined AGNs based on optical surveys. We conclude that q 24 is a more reliable indicator of radio-loudness. Use of RL should be confined to the optically selected type 1 AGN.

  8. Miniaturized, High-Speed, Modulated X-Ray Source

    NASA Technical Reports Server (NTRS)

    Gendreau, Keith; Arzoumanian, Zaven; Kenyon, Steve; Spartana, Nick

    2013-01-01

    A low-cost, miniature x-ray source has been developed that can be modulated in intensity from completely off to full intensity on nanosecond timescales. This modulated x-ray source (MXS) has no filaments and is extremely rugged. The energy level of the MXS is adjustable from 0 to more than 100 keV. It can be used as the core of many new devices, providing the first practical, arbitrarily time-variable source of x-rays. The high-speed switching capability and miniature size make possible many new technologies including x-ray-based communication, compact time-resolved x-ray diffraction, novel x-ray fluorescence instruments, and low- and precise-dose medical x-rays. To make x-rays, the usual method is to accelerate electrons into a target material held at a high potential. When the electrons stop in the target, x-rays are produced with a spectrum that is a function of the target material and the energy to which the electrons are accelerated. Most commonly, the electrons come from a hot filament. In the MXS, the electrons start off as optically driven photoelectrons. The modulation of the x-rays is then tied to the modulation of the light that drives the photoelectron source. Much of the recent development has consisted of creating a photoelectrically-driven electron source that is robust, low in cost, and offers high intensity. For robustness, metal photocathodes were adopted, including aluminum and magnesium. Ultraviolet light from 255- to 350-nm LEDs (light emitting diodes) stimulated the photoemissions from these photocathodes with an efficiency that is maximized at the low-wavelength end (255 nm) to a value of roughly 10(exp -4). The MXS units now have much higher brightness, are much smaller, and are made using a number of commercially available components, making them extremely inexpensive. In the latest MXS design, UV efficiency is addressed by using a high-gain electron multiplier. The photocathode is vapor-deposited onto the input cone of a Burle Magnum(TradeMark) multiplier. This system yields an extremely robust photon-driven electron source that can tolerate long, weeks or more, exposure to air with negligible degradation. The package is also small. When combined with the electron target, necessary vacuum fittings, and supporting components (but not including LED electronics or high-voltage sources), the entire modulated x-ray source weighs as little as 158 grams.

  9. Planetary Science Advances with the International X-ray Observatory

    NASA Astrophysics Data System (ADS)

    Feigelson, Eric; Elsner, R.; Glassgold, A.; Guedel, M.; Montmerle, T.; Wargelin, B.; Wolk, S.

    2009-01-01

    X-ray studies of planetary systems are beginning to provide important insights inaccessible at other wavelengths. In our Solar System, charge exchange emission from solar particles is faint and variable with complex spectra, a situation well-matched to the planned International X-ray Observatory's high-throughput and high spectral resolution. Solar-type stars universally exhibit enhanced magnetic activity during their youth so that X-ray studies reveal the high-energy inputs to protoplanetary disks and planetary atmospheres. It is possible that X-ray illumination is a critical regulator to the formation of planets. This paper is based on the report of the Con-X ``Solar System, Planet Formation and Evolution'' Science Panel. (1) X-ray irradiation of protoplanetary disks can be probed with the 6.4 keV iron fluorescent line. Seen in a handful of protostars with Chandra and XMM, IXO will survey the line in hundreds of young stellar systems and will quantify the 10-30 keV emission stellar emission that can penetrate deep into the disk. In a few cases, X-ray `superflares' will permit disk reverberation mapping. Combined with infrared and submillimeter studies, IXO will establish the importance of X-ray illumination on protoplanetary disk physics and chemistry. (2) Planetary atmospheres show rapidly varying X-ray components from charge exchange of heavy solar wind ions, electron bremsstrahlung continuum from ion-neutral interactions, and scattering and fluorescence of solar X-ray emission. IXO will produce a movie of these effects in Jupiter as the planet rotates and responds to solar flare/CME events. IXO study of the remarkable Martian X-ray exosphere will constrain the evaporation of planetary atmospheres. Three additional science programs are outlined: study of charge exchange processes in cometary comae; spectroscopy of diffuse heliospheric charge exchange X-rays previously attributed to the hot local interstellar medium; and measurements of flaring in stars hosting extrasolar planets in the Habitable Zone to evaluate atmospheric evaporation.

  10. Millimeter, microwave, hard X-ray, and soft X-ray observations of energetic electron populations in solar flares

    NASA Technical Reports Server (NTRS)

    Kundu, M. R.; White, S. M.; Gopalswamy, N.; Lim, J.

    1994-01-01

    We present comparisons of multiwavelength data for a number of solar flares observed during the major campaign of 1991 June. The different wavelengths are diagnostics of energetic electrons in different energy ranges: soft X-rays are produced by electrons with energies typically below 10 keV, hard X-rays by electrons with energies in the range 10-200 keV, microwaves by electrons in the range 100 keV-1 MeV, and millimeter-wavelength emission by electrons with energies of 0.5 MeV and above. The flares in the 1991 June active period were remarkable in two ways: all have very high turnover frequencies in their microwave spectra, and very soft hard X-ray spectra. The sensitivity of the microwave and millimeter data permit us to study the more energetic (greater than 0.3 MeV) electrons even in small flares, where their high-energy bremsstrahlung is too weak for present detectors. The millimeter data show delays in the onset of emission with respect to the emissions associated with lower energy electrons and differences in time profiles, energy spectral indices incompatible with those implied by the hard X-ray data, and a range of variability of the peak flux in the impulsive phase when compared with the peak hard X-ray flux which is two orders of magnitude larger than the corresponding variability in the peak microwave flux. All these results suggest that the hard X-ray-emitting electrons and those at higher energies which produce millimeter emission must be regarded as separate populations. This has implications for the well-known 'number problem' found previously when comparing the numbers of non thermal electrons required to produce the hard X-ray and radio emissions.

  11. A proposed method to reconstruct the three-dimensional dispersion profile of polymeric fibres based on variable wavelength interferometry.

    PubMed

    Hamza, A A; Sokkar, T Z N; El-Farahaty, K A; Raslan, M I

    2015-02-01

    In this paper, we suggest a modification to the conventional variable wavelength interferometry. This modification allowed us to calculate the dispersion curve of each point inside polymeric fibres instead of calculating the mean dispersion of these fibres. This modified mathematical treatment was used to calculate the three-dimensional dispersion profile of isotactic polypropylene fibres suffering from necking deformation. The different steps of calculating the three-dimensional dispersion profile of the fibre were demonstrated. The application of this modified method revealed the variation of the fibre material dispersion before, inside and after the necking region. In addition, the birefringence profile of the necked isotactic polypropylene was determined using the proposed mathematical treatment. This allowed us to diagnose the interaction of the incident waves with necked polypropylene fibres, which gives extensive information on the orientation of the molecular chains during the formation of the necking phenomenon. PMID:25354726

  12. 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

  13. Portable X-Ray Device

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Portable x-ray instrument developed by NASA now being produced commercially as an industrial tool may soon find further utility as a medical system. The instrument is Lixiscope - Low Intensity X-Ray Imaging Scope -- a self-contained, battery-powered fluoroscope that produces an instant image through use of a small amount of radioactive isotope. Originally developed by Goddard Space Flight Center, Lixiscope is now being produced by Lixi, Inc. which has an exclusive NASA license for one version of the device.

  14. Anomalous lattice expansion in yttria stabilized zirconia under simultaneous applied electric and thermal fields: A time-resolved in situ energy dispersive x-ray diffractometry study with an ultrahigh energy synchrotron probe

    SciTech Connect

    Akdogan, E. K.; Savkl Latin-Small-Letter-Dotless-I y Latin-Small-Letter-Dotless-I ld Latin-Small-Letter-Dotless-I z, I.; Bicer, H.; Paxton, W.; Toksoy, F.; Tsakalakos, T. [Department of Materials Science and Engineering, Rutgers University, Piscataway, New Jersey 08854-8065 (United States)] [Department of Materials Science and Engineering, Rutgers University, Piscataway, New Jersey 08854-8065 (United States); Zhong, Z. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)] [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2013-06-21

    Nonisothermal densification in 8% yttria doped zirconia (8YSZ) particulate matter of 250 nm median particle size was studied under 215 V/cm dc electric field and 9 Degree-Sign C/min heating rate, using time-resolved in-situ high temperature energy dispersive x-ray diffractometry with a polychromatic 200 keV synchrotron probe. Densification occurred in the 876-905 Degree-Sign C range, which resulted in 97% of the theoretical density. No local melting at particle-particle contacts was observed in scanning electron micrographs, implying densification was due to solid state mass transport processes. The maximum current draw at 905 Degree-Sign C was 3 A, corresponding to instantaneous absorbed power density of 570 W/cm{sup 3}. Densification of 8YSZ was accompanied by anomalous elastic volume expansions of the unit cell by 0.45% and 2.80% at 847 Degree-Sign C and 905 Degree-Sign C, respectively. The anomalous expansion at 905 Degree-Sign C at which maximum densification was observed is characterized by three stages: (I) linear stage, (II) anomalous stage, and (III) anelastic recovery stage. The densification in stage I (184 s) and II (15 s) was completed in 199 s, while anelastic relaxation in stage III lasted 130 s. The residual strains ({epsilon}) at room temperature, as computed from tetragonal (112) and (211) reflections, are {epsilon}{sub (112)} = 0.05% and {epsilon}{sub (211)} = 0.13%, respectively. Time dependence of (211) and (112) peak widths ({beta}) show a decrease with both exhibiting a singularity at 905 Degree-Sign C. An anisotropy in (112) and (211) peak widths of {l_brace} {beta}{sub (112)}/{beta}{sub (211)}{r_brace} = (3:1) magnitude was observed. No phase transformation occurred at 905 Degree-Sign C as verified from diffraction spectra on both sides of the singularity, i.e., the unit cell symmetry remains tetragonal. We attribute the reduction in densification temperature and time to ultrafast ambipolar diffusion of species arising from the superposition of mass fluxes due to Fickian diffusion, thermodiffusion (Soret effect), and electromigration, which in turn are a consequence of a superposition of chemical, temperature, and electrical potential gradients. On the other hand, we propose defect pile-up at particle-particle contacts and subsequent tunneling as a mechanism creating the 'burst-mode' discontinuous densification at the singularities observed at 847 and 905 Degree-Sign C.

  15. Analysis of the Deformation Behavior of Magnesium-Rare Earth Alloys Mg-2 pct Mn-1 pct Rare Earth and Mg-5 pct Y-4 pct Rare Earth by In Situ Energy-Dispersive X-ray Synchrotron Diffraction and Elasto-Plastic Self-Consistent Modeling

    NASA Astrophysics Data System (ADS)

    Lentz, Martin; Klaus, Manuela; Coelho, Rodrigo S.; Schaefer, Nobert; Schmack, Florian; Reimers, Walter; Clausen, Bjørn

    2014-09-01

    The deformation behavior of the Mg-RE alloys ME21 and WE54 was investigated. Although both alloys contain rare earth elements, which alter and weaken the texture, the flow curves of the alloys deviate significantly, especially in uniaxial compression test. Apart from the higher strength of the WE54 alloy, the compression flow curve does not exhibit the typical sigmoidal shape, which is associated with tension twinning. However, optical microscopy, X-ray texture measurements, and EBSD analysis reveal the activity of tension twinning. The combination of in situ energy-dispersive X-ray synchrotron diffraction and EPSC modeling was used to analyze these differences. The investigation reveals that twin propagation is decelerated in the WE54 alloy, which requires a change of the twinning scheme from the `finite initial fraction' to the `continuity' assumption. Furthermore, an enhanced activity of the pyramidal slip system was observed in case of the WE54 alloy.

  16. Analysis of the Deformation Behavior of Magnesium-Rare Earth Alloys Mg-2 pct Mn-1 pct Rare Earth and Mg-5 pct Y-4 pct Rare Earth by In Situ Energy-Dispersive X-ray Synchrotron Diffraction and Elasto-Plastic Self-Consistent Modeling

    NASA Astrophysics Data System (ADS)

    Lentz, Martin; Klaus, Manuela; Coelho, Rodrigo S.; Schaefer, Nobert; Schmack, Florian; Reimers, Walter; Clausen, Bjørn

    2014-11-01

    The deformation behavior of the Mg-RE alloys ME21 and WE54 was investigated. Although both alloys contain rare earth elements, which alter and weaken the texture, the flow curves of the alloys deviate significantly, especially in uniaxial compression test. Apart from the higher strength of the WE54 alloy, the compression flow curve does not exhibit the typical sigmoidal shape, which is associated with tension twinning. However, optical microscopy, X-ray texture measurements, and EBSD analysis reveal the activity of tension twinning. The combination of in situ energy-dispersive X-ray synchrotron diffraction and EPSC modeling was used to analyze these differences. The investigation reveals that twin propagation is decelerated in the WE54 alloy, which requires a change of the twinning scheme from the `finite initial fraction' to the `continuity' assumption. Furthermore, an enhanced activity of the < c+ a> pyramidal slip system was observed in case of the WE54 alloy.

  17. Wavelength dispersion of the local field intensity in silver-gold nanocages.

    PubMed

    Pilot, R; Zoppi, A; Trigari, S; Deepak, F L; Giorgetti, E; Bozio, R

    2015-03-21

    This study provides a combined theoretical and experimental analysis of the far-field (extinction) and of the near-field (SERS enhancement) spectral distribution in hollow nanoparticles, that is, silver-gold nanocages (NCs). Chitosan protected NCs have been synthesized by a galvanic replacement-based procedure: their morphological properties and chemical composition have been characterized by TEM, STEM and ICP. NCs were then functionalized with a thiolated organic dye prior to carrying out SERS measurements. Finite Element Method simulations of a single NC have shown that the field enhancement at the excitation wavelength follows the same spectral dependence as the extinction spectrum and, consequently, the SERS enhancement profile, as a function of the excitation wavelength, peaks at higher energy with respect to extinction. The simulated extinction is remarkably narrower than the experimental spectrum of NCs in solution, indicating that the colloidal sample is substantially polydispersed. However, a simple qualitative model that we have developed would suggest that the SERS enhancement profile is blue-shifted with respect to the extinction in the presence of polydispersivity as well. In addition, NC dimers have been simulated: both their extinction and near field-spectra shift to the red when the size of the gap is reduced analogous to what happens with dimers of filled spherical nanoparticles (NPs). In addition, simulations also revealed that a NC dimer is only slightly more efficient in amplifying the field with respect to the isolated NC, and this behavior is peculiar to NCs. In fact, filled spherical NP dimers exhibit a remarkably stronger field enhancement with respect to the isolated NP. By means of Wavelength Scanned SERS, we measured the spectral distribution of the local field in a dispersion of NCs. We observed experimentally that the local field is distributed in the same spectral region as the extinction and that the absolute value of the SERS enhancement factor maintains a low value throughout the range explored (568-800 nm). We propose that the observed correlation between the SERS profile and the extinction is accidental and originates from the limited increase in amplification provided by NC aggregates with respect to isolated NCs. PMID:25698217

  18. Growth of K(Cl, Br) crystals from aqueous solutions in an X-ray field

    NASA Astrophysics Data System (ADS)

    Anishchik, V. M.; Val'Ko, N. G.; Vo?na, V. V.; Vorontsov, A. S.

    2008-07-01

    The influence of X-rays of different wavelength on the degree of structural quality of K(Cl, Br) crystals of mixed composition grown from aqueous solutions is considered. It is found by the methods of chemical etching, X-ray analysis, pycnometric density, and atomic-force microscopy that X-ray irradiation leads to the formation of crystals with a more perfect substructure and surface morphology and a decrease of the dislocation density and concentration of pores and cavities containing the mother liquor. It is shown that X-ray irradiation can promote preferential incorporation of less electronegative components into the crystal lattice of a solid solution.

  19. The effect of vacuum birefringence on the polarization of X-ray binaries and pulsars

    NASA Technical Reports Server (NTRS)

    Novick, R.; Weisskopf, M. C.; Angel, J. R. P.; Sutherland, P. G.

    1977-01-01

    In a strong magnetic field the vacuum becomes birefringent. This effect is especially important for pulsars at X-ray wavelengths. Any polarized X-ray emission from the surface of a magnetic neutron star becomes depolarized as it propagates through the magnetic field. The soft X-ray emission from AM Her, believed to be a magnetic white dwarf, may show about one radian of phase retardation. In this case, circular polarization of the X-ray flux would be a characteristic signature of vacuum birefringence.

  20. Exploring Cosmic X-ray Source Polarization

    NASA Technical Reports Server (NTRS)

    Swank, Jean Hebb; Jahodal, K.; Kallman, T. R.; Kaaret, P.

    2008-01-01

    Cosmic X-ray sources are expected to be polarized, either because of their asymmetry and the role of scattering in their emission or the role of magnetic fields. Polarization at other wavelengths has been useful. X-ray polarization will provide a new handle on black hole parameters, in particular the spin, on accretion flows and outflows, on neutron star spin orientations and emission mechanisms, on the quantum mechanical effects of super-strong magnetic fields of magnetars, and on the structure of supernovae shocks. The proposed Gravity and Extreme Magnetism SMEX (GEMS) will use high efficiency polarimeters behind thin foil mirrors. The statistical sensitivity and control of systematics will allow measurement of polarization fractions as small as 1% from many galactic and extragalactic sources. Targets which should be polarized at the level that GEMS can easily measure include stellar black holes, Seyfert galaxies and quasars, blazars, rotation-powered and accretion-powered pulsars, magnetars, shell supernova remnants and pulsar wind nebulae. The polarimeters are Time Projection Chambers that allow reconstruction of images of photoelectron tracks for 2-10 keV Xrays. They can be deep without sacrificing modulation. These polarimeters do not image the sky, but the telescope point spread function and detector collimation allow structure to be resolved at the 10 arcmin level. Rotation of the spacecraft is not needed for the signal measurement in the Time Projection Chambers, but provides for measurement and correction of systematic errors. It also allows a small Bragg reflection soft X-ray experiment to be included that can be used for isolated neutron stars and blazars.