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1

Small Angle X-Ray Scattering Detector  

DOE Patents (OSTI)

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

Hessler, Jan P.

2004-06-15T23:59:59.000Z

2

Anomalous Small-angle Scattering with Soft X-rays at Al and Si K ...  

Science Conference Proceedings (OSTI)

Anomalous Small-angle Scattering with Soft X-rays at Al and Si K Absorption ... and Cooling Cycles in a High Strength Quenched and Tempered Structural Steel.

3

Materials Small-angle X-ray Scattering (SAXS) | Stanford Synchrotron  

NLE Websites -- All DOE Office Websites (Extended Search)

Materials Small-angle X-ray Scattering (SAXS) Materials Small-angle X-ray Scattering (SAXS) Small Angle X-ray Scattering for Materials Science Small-angle X-ray scattering (SAXS) is a well-established characterization method for microstructure investigations in various materials. It probes electron density differences to give information about structural inhomogeneities from the near atomic scale (1 nm) to the micron scale (1 000 nm). The method involves measuring the scattered X-ray intensity as a function of (typically small) scattering angles and is generally performed in transmission. SAXS is used to characterize the size scale of inhomogeneities (e.g. pores, inclusions, second phase regions) in polymer blends, micro-emulsions, geological materials, bones, cements and ceramics. Instrumentation

4

BIOISIS: Biological Macromolecules by Small Angle X-ray Scattering (SAXS)  

DOE Data Explorer (OSTI)

BIOISIS is an open access database dedicated to the study of biological macromolecules by small angle X-ray scattering (SAXS). BIOISIS aims to become the complete source for the deposition, distribution and maintenance of small angle X-ray scattering data and technologies. The database is designed around the concept of an ôexperimentö and relates a specific experiment to a set of genes, organisms, computational models and experimental data. As of May 2012, BIOSIS contains 7,118 genes covering four different organisms. Forty-two modeled structures are available. Clicking on a structures reveals scattering curves, experimental conditions, and experimental values. The data are collected at Beamline 12.3.1 of the Advanced Light Source (ALS).[Copied with editing from http://www.bioisis.net/about

Tainer, John (Scripps Research Institute); Hura, Greg (LBNL); Rambo, Robert P. (LBNL)

5

Note: Grazing incidence small and wide angle x-ray scattering combined with imaging ellipsometry  

SciTech Connect

The combination of grazing incidence small angle x-ray scattering (GISAXS) and grazing incidence wide angle x-ray scattering (GIWAXS) with optical imaging ellipsometry is presented as an upgrade of the available measurement techniques at the wiggler beamline BW4 of the Hamburger Synchrotronstrahlungslabor. The instrument is introduced with the description of the alignment procedure to assure the measurement of imaging ellipsometry and GISAXS/GIWAXS on the same sample spot. To demonstrate the possibilities of the new instrument examples of morphological investigation on films made of poly(3-hexylthiophene) and [6,6]-phenyl-C{sub 61} butyric acid methyl ester as well as textured poly(9,9-dioctylfluorene-alt-benzo-thia-diazole) are shown.

Koerstgens, V.; Meier, R.; Ruderer, M. A.; Guo, S.; Chiang, H.-Y.; Mueller-Buschbaum, P. [Technische Universitaet Muenchen, Physik-Department, Lehrstuhl fuer Funktionelle Materialien, James-Franck-Str. 1, 85748 Garching (Germany); Perlich, J.; Roth, S. V.; Gehrke, R. [HASYLAB, DESY, Notkestr. 85, 22607, Hamburg (Germany)

2012-07-15T23:59:59.000Z

6

Time-Resolved Small-Angle X-ray Scattering Studies Revealed Three Kinetic  

NLE Websites -- All DOE Office Websites (Extended Search)

June 2010 June 2010 Time-Resolved Small-Angle X-ray Scattering Studies Revealed Three Kinetic Stages of a T=4 Virus Maturation Most eukaryotic viruses, including HIV, influenza and herpes viruses, undergo maturation when transitioning from the noninfectious provirion to the infectious virion. Maturation processes involve reorganization of viral quaternary structure to defend viral gene from the cellular defense mechanism and lead to effective transfection. Nudaurelia capensis omega virus, NwV, is a T=4, non-enveloped, icosahedral, single strand RNA virus, where T is the triangulation number defining an icosahedral lattice of the virus capsid structure. Virus like particles (VLPs) of NwV exhibit large pH-dependent conformational changes (LCC) when the procapsid, purified at pH=7.6, (~480 Å) is exposed to pH=5.0, resulting in ~400 Å particles (Figure 1). In response to the LCC, an auto-proteolysis occurs in which each of 240 subunits is cleaved at Asn570-Phe571 (1). We investigated this pH-induced maturation by equilibrium and time-resolved small angle X-ray scattering (SAXS) at SSRL beam line 4-2.

7

Robust, high-throughput solution structural analyses by small angle X-ray scattering (SAXS)  

Science Conference Proceedings (OSTI)

We present an efficient pipeline enabling high-throughput analysis of protein structure in solution with small angle X-ray scattering (SAXS). Our SAXS pipeline combines automated sample handling of microliter volumes, temperature and anaerobic control, rapid data collection and data analysis, and couples structural analysis with automated archiving. We subjected 50 representative proteins, mostly from Pyrococcus furiosus, to this pipeline and found that 30 were multimeric structures in solution. SAXS analysis allowed us to distinguish aggregated and unfolded proteins, define global structural parameters and oligomeric states for most samples, identify shapes and similar structures for 25 unknown structures, and determine envelopes for 41 proteins. We believe that high-throughput SAXS is an enabling technology that may change the way that structural genomics research is done.

Hura, Greg L.; Menon, Angeli L.; Hammel, Michal; Rambo, Robert P.; Poole II, Farris L.; Tsutakawa, Susan E.; Jenney Jr, Francis E.; Classen, Scott; Frankel, Kenneth A.; Hopkins, Robert C.; Yang, Sungjae; Scott, Joseph W.; Dillard, Bret D.; Adams, Michael W. W.; Tainer, John A.

2009-07-20T23:59:59.000Z

8

Small angle x-ray scattering studies of carbon anodes used in lithium rechargeable batteries.  

DOE Green Energy (OSTI)

In ANL laboratories, disordered carbons with predictable surface area and porosity properties have been prepared using inorganic templates containing well defined pore sizes. The carbons have been tested in electrochemical cells as anodes in lithium secondary batteries. They deliver high specific capacity and display excellent performance in terms of the number of cycles run. In situ small angle X-ray scattering (SAXS) during electrochemical cycling was carried out at the Advanced Photon Source, at ANL. In order to monitor the carbon electrode structural changes upon cycling, an electrochemical cell was specially designed to allow for the application of electrical current and the collection of SAXS data at the same time. Results show that upon cycling the structure of the carbon remains unchanged, which is desirable in reversible systems.

Sandi, G.; Carrado, K. A.; Winans, R. E.; Seifert, S.; Johnson, C. S.

1999-11-16T23:59:59.000Z

9

Small-angle x-ray scattering measurements of the microstructure of liquid helium mixtures adsorbed in aerogel  

Science Conference Proceedings (OSTI)

Small-angle x-ray scattering (SAXS) was used to measure the microstructure of isotopic mixtures of {sup 3}He and {sup 4}He adsorbed into silica aerogels as a function of temperature and {sup 3}He concentration. The SAXS measurements could be well described by the formation of a nearly pure film of {sup 4}He which separates from the bulk mixture onto the aerogel strands and which thickens with decreasing temperature. Previous observations of a superfluid {sup 3}He-rich phase are consistent with superfluidity existing within this film phase. Observed differences between different density aerogels are explained in terms of the depletion of {sup 4}He from the bulk mixture due to film formation.

Lurio, L. B.; Mulders, N.; Paetkau, M.; Chan, M. H. W.; Mochrie, S. G. J. [Department of Physics, Northern Illinois University, DeKalb, Illinois 60115 (United States); Department of Physics, University of Delaware, Newark, Delaware 19716 (United States); Department of Physics and Astronomy, Okanagan College, British Columbia V1Y4X8 (Canada); Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Department of Physics, Yale University, New Haven, Connecticut 06511 (United States)

2007-07-15T23:59:59.000Z

10

Microstructural Mapping Using High-Energy X-Ray Scattering  

Science Conference Proceedings (OSTI)

Abstract Scope, Advanced characterization methods at the APS permit unique in- situ ... The combination of an undulator source, brilliance preserving optics and focusing .... Ultra-Small-Angle X-Ray Scattering—X-Ray Photon Correlation ...

11

In-situ small-angle X-ray scattering study of the precipitation behavior in a Fe-25 at.%Co-9 at.%Mo alloy  

Science Conference Proceedings (OSTI)

Fe-Co-Mo alloys show extraordinary mechanical properties which make them potential candidates for various high-performance applications. In the present study, for the first time, the precipitation behavior in a Fe-25 at.%Co-9 at.%Mo alloy was studied by small-angle X-ray scattering using high-energy synchrotron radiation. The specimens were isothermally aged in an in-situ furnace. The small-angle X-ray scattering patterns showed scaling behavior and were evaluated by employing a model function from the literature. This approach provides information about the characteristic length scale and the volume fraction of the precipitates in the alloy.

Zickler, Gerald A. [Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Christian Doppler Laboratory for Early Stages of Precipitation, Montanuniversitaet Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria)], E-mail: gerald.zickler@mu-leoben.at; Eidenberger, Elisabeth [Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Leitner, Harald [Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Christian Doppler Laboratory for Early Stages of Precipitation, Montanuniversitaet Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Stergar, Erich; Clemens, Helmut [Department of Physical Metallurgy and Materials Testing, Montanuniversitaet Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Staron, Peter; Lippmann, Thomas; Schreyer, Andreas [GKSS Research Center Geesthacht, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany)

2008-12-15T23:59:59.000Z

12

Mass fractal characteristics of silica sonogels as determined by small-angle x-ray scattering and nitrogen adsorption  

SciTech Connect

A sample series of silica sonogels was prepared using different water-tetraethoxysilane molar ratio (r{sub w}) in the gelation step of the process in order to obtain aerogels with different bulk densities after the supercritical drying. The samples were analyzed by means of small-angle x-ray-scattering (SAXS) and nitrogen-adsorption techniques. Wet sonogels exhibit mass fractal structure with fractal dimension D increasing from {approx}2.1 to {approx}2.4 and mass-fractal correlation length {xi} diminishing from {approx}13 nm to {approx}2 nm, as r{sub w} is changed in the nominal range from 66 to 6. The process of obtaining aerogels from sonogels and heat treatment at 500 deg. C, in general, increases the mass-fractal dimension D, diminishes the characteristic length {xi} of the fractal structure, and shortens the fractal range at the micropore side for the formation of a secondary structured particle, apparently evolved from the original wet structure at a high resolution level. The overall mass-fractal dimension D of aerogels was evaluated as {approx}2.4 and {approx}2.5, as determined from SAXS and from pore-size distribution by nitrogen adsorption, respectively. The fine structure of the 'secondary particle' developed in the obtaining of aerogels could be described as a surface-mass fractal, with the correlated surface and mass-fractal dimensions decreasing from {approx}2.4 to {approx}2.0 and from {approx}2.7 to {approx}2.5, respectively, as the aerogel bulk density increases from 0.25 (r{sub w}=66) up to 0.91 g/cm{sup 3} (r{sub w}=6)

Donatti, D.A.; Vollet, D.R.; Ibanez Ruiz, A.; Mesquita, A.; Silva, T.F.P. [Unesp-Universidade Estadual Paulista, IGCE, Departamento de Fisica, P.O. Box 178 CEP, 13500-970 Rio Claro, Sao Paulo (Brazil)

2005-01-01T23:59:59.000Z

13

Fluctuation X-Ray Scattering  

SciTech Connect

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

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

2013-01-25T23:59:59.000Z

14

Dynamic investigation of gold nanocrystal assembly using in situ grazing-incidence small angle x-ray scattering.  

SciTech Connect

Here we investigate the dynamic self-assembly pathway of ordered gold nanocrystal arrays during the self-assembly of gold nanocrystal micelles, with and without the presence of colloidal silica precursors, using grazing-incidence X-ray scattering performed at a synchrotron source. With silica precursors present, a lattice with rhombohedral symmetry is formed from the partial collapse of a face-centered cubic structure. In the absence of silica, a transient body-centered orthorhombic phase appears, which rapidly collapses into a glassy nanocrystal film. The appearance of face-centered and body-centered structures is consistent with a phase diagram for charged colloidal particles with assembly modulated via Coulomb screening.

Dunphy, D.; Fan, H.; Li, X.; Wang, J.; Brinker, C. J.; X-Ray Science Division; Univ. of New Mexico; SNL

2008-01-01T23:59:59.000Z

15

Direct three-dimensional coherently scattered x-ray microtomography  

Science Conference Proceedings (OSTI)

Purpose: It has been shown that coherently scattered x rays can be used to discriminate and identify specific components in a mixture of low atomic weight materials. The authors demonstrated a new method of doing coherently scattered x-ray tomography with a thin sheet of x ray. Methods: A collimated x-ray fan-beam, a parallel polycapillary collimator, and a phantom consisting of several biocompatible materials of low attenuation-based contrast were used to investigate the feasibility of the method. Because of the particular experimental setup, only the phantom translation perpendicular to the x-ray beam is needed and, thus, there is no need of Radon-type tomographic reconstruction, except for the correction of the attenuation to the primary and scattered x rays, which was performed by using a conventional attenuation-based tomographic image data set. The coherent scatter image contrast changes with momentum transfer among component materials in the specimen were investigated with multiple x-ray sources with narrow bandwidth spectra generated with anode and filter combinations of Cu/Ni (8 keV), Mo/Zr (18 keV), and Ag/Pd (22 keV) and at multiple scatter angles by orienting the detector and polycapillary collimator at different angles to the illuminating x ray. Results: The contrast among different materials changes with the x-ray source energy and the angle at which the image was measured. The coherent scatter profiles obtained from the coherent scatter images are consistent with the published results. Conclusions: This method can be used to directly generate the three-dimensional coherent scatter images of small animal, biopsies, or other small objects with low atomic weight biological or similar synthetic materials with low attenuation contrast. With equipment optimized, submillimeter spatial resolution may be achieved.

Cui Congwu; Jorgensen, Steven M.; Eaker, Diane R.; Ritman, Erik L. [Department of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada); Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street Southwest, Alfred Building 2-409, Rochester, Minnesota 55905 (United States)

2010-12-15T23:59:59.000Z

16

Inelastic X-ray and Nuclear Resonant Scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

Beamlines Divisions Argonne Home > Advanced Photon Source > Inelastic X-ray and Nuclear Resonant Scattering The Inelastic X-ray and Nuclear Resonant Scattering group...

17

Ray tracing flux calculation for the small and wide angle x-ray scattering diffraction station at the SESAME synchrotron radiation facility  

SciTech Connect

The calculation for the optics of the synchrotron radiation small and wide angle x-ray scattering beamline, currently under construction at SESAME is described. This beamline is based on a cylindrically bent germanium (111) single crystal with an asymmetric cut of 10.5 deg., followed by a 1.2 m long rhodium coated plane mirror bent into a cylindrical form. The focusing properties of bent asymmetrically cut crystals have not yet been studied in depth. The present paper is devoted to study of a particular application of a bent asymmetrically cut crystal using ray tracing simulations with the SHADOW code. These simulations show that photon fluxes of order of 1.09x10{sup 11} photons/s will be available at the experimental focus at 8.79 keV. The focused beam dimensions will be 2.2 mm horizontal full width at half maximum (FWHM) by 0.12 mm vertical (FWHM).

Salah, Wa'el [Synchrotron-light for Experimental Science and Application in the Middle East (SESAME), P.O. Box 7, Allan 19252 (Jordan); Department of Physics, The Hashemite University, Zarqa 13115 (Jordan); Sanchez del Rio, M. [European Synchrotron Radiation Facility, Bp 220, 38043 Grenoble Cedex (France); Hoorani, H. [Synchrotron-light for Experimental Science and Application in the Middle East (SESAME), P.O. Box 7, Allan 19252 (Jordan)

2009-09-15T23:59:59.000Z

18

Kinetics of HEX-BCC Transition in a Triblock Copolymer in a Selective Solvent: Time Resolved Small Angle X-ray Scattering Measurements and Model Calculations  

E-Print Network (OSTI)

Time-resolved small angle x-ray scattering (SAXS) was used to examine the kinetics of the transition from HEX cylinders to BCC spheres at various temperatures in poly(styrene-b- ethylene-co-butylene-b-styrene) (SEBS) in mineral oil, a selective solvent for the middle EB block. Temperature-ramp SAXS and rheology measurements show the HEX to BCC order-order transition (OOT) at ~127 oC and order-disorder transition (ODT) at ~180 oC. We also observed the metastability limit of HEX in BCC with a spinodal temperature, Ts ~ 150 oC. The OOT exhibits 3 stages and occurs via a nucleation and growth mechanism when the final temperature Tf peak into two peaks when the cylinder spacing and modulation wavelength are incommensurate predicted by the model is confirmed by analysis of the SAXS data.

Minghai Li; Yongsheng Liu; Huifen Nie; Rama Bansil; Milos Steinhart

2007-10-24T23:59:59.000Z

19

Massively parallel X-ray scattering simulations  

Science Conference Proceedings (OSTI)

Although present X-ray scattering techniques can provide tremendous information on the nano-structural properties of materials that are valuable in the design and fabrication of energy-relevant nano-devices, a primary challenge remains in the analyses ...

Abhinav Sarje; Xiaoye S. Li; Slim Chourou; Elaine R. Chan; Alexander Hexemer

2012-11-01T23:59:59.000Z

20

Surface Area and Microporosity of Carbon Aerogels from Gas Adsorption and Small- and Wide-Angle X-ray Scattering Measurements  

E-Print Network (OSTI)

A carbon aerogel was obtained by carbonization of an organic aerogel prepared by sol-gel polymerization of resorcinol and formaldehyde in water. The carbon aerogel was then CO2 activated at 800 °C to increase its surface area and widen its microporosity. Evolution of these parameters was followed by gas adsorption and small- and wide-angle X-ray scattering (SAXS and WAXS, respectively) with contrast variation by using dry and wet (immersion in benzene and m-xylene) samples. For the original carbon aerogel, the surface area, SSAXS, obtained by SAXS, is larger than that obtained by gas adsorption (Sads). The values become nearly the same as the degree of activation of the carbon aerogel increases. This feature is due to the widening of the narrow microporosity in the carbon aerogel as the degree of activation is increased. In addition, WAXS results show that the short-range spatial correlations into the assemblies of hydrocarbon molecules confined inside the micropores are different from those existing in the liquid phase. 1.

David Fairén-jiménez; Francisco Carrasco-marín; David Djurado; Françoise Bley; Françoise Ehrburger-dolle; Carlos Moreno-castilla

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Characterization of nanostructured zirconia prepared by hydrolysis and reverse micelle synthesis by small-angle neutron and X-ray scattering  

DOE Green Energy (OSTI)

Low temperature techniques such as hydrolysis and reverse micelle syntheses provide the opportunity to determine the relationship between the structural properties and preparation conditions of zirconia powders as well as to tailor their physicochemical properties. The authors have performed small-angle neutron and synchrotron X-ray scattering (SANS and SAXS) experiments to study the nucleation and organization of zirconia nanoparticles via different preparation routes. First, the formation of reverse micelles in individual and mixed solutions of (ZrOCl{sub 2}+D{sub 2}O)/AOT/C{sub 6}D{sub 5}CD{sub 3}, and (NH{sub 4}OH+H{sub 2}O)/AOT/C{sub 6}D{sub 5}CD{sub 3} systems at water/AOT molar ratio of 20 was characterized. Second, the aggregation of zirconia gels obtained from the reaction of the reverse micelle solutions after heat treatments was studied. Third, the nanostructure of zirconia powders prepared by the reverse micelle method is compared with the corresponding powders prepared by hydrolysis after different heat treatments.

Thiyagarajan, P.; Li, X.; Littrell, K.; Seifert, S.; Csencsits, R.; Loong, C.

1999-12-07T23:59:59.000Z

22

Small-angle x-ray scattering studies of microvoids in amorphous silicon-based semiconductors. Annual subcontract report, 1 February 1992--31 January 1993  

DOE Green Energy (OSTI)

This report describes work to provide now details of the microstructure for the size scale from about 1 nm to 30 nm in high-quality a-Si:H and related alloys prepared by current state-of-the-art deposition methods as well as by now and emerging deposition technologies to help determine the role of microvoids and other density fluctuations in controlling the opto-electronic properties. The objectives are to determine whether the presence of microstructure as detected by small-angle X-ray scattering (SAXS) (1) limits the photovoltaic (PV) properties of device-quality a-Si:H; (2) plays a role in determine the photostability of a-Si:H; and (3) is responsible for degradation of the PV properties due to alloying with Ge, C, and other constituents. We collaborated with several groups that can supply relevant systematic sets of samples and the associated opto-electronic data to help address these issues. The project also included developing a method to standardize the procedures, minimize substrate influences, and implement improved data reduction and modeling methodology.

Williamson, D.L.; Jones, S.J.; Chen, Y. [Colorado School of Mines, Golden, CO (United States)

1994-06-01T23:59:59.000Z

23

X?ray Fluorescence (XRF) Assay Using Laser Compton Scattered (LCS) X?rays  

Science Conference Proceedings (OSTI)

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

Syed F. Naeem; Khalid Chouffani; Douglas P. Wells

2009-01-01T23:59:59.000Z

24

HIGH BRILLIANCE X-RAY SCATTERING FOR  

NLE Websites -- All DOE Office Websites (Extended Search)

BRILLIANCE X-RAY SCATTERING FOR BRILLIANCE X-RAY SCATTERING FOR LIFE SCIENCES (LIX) Group Leader: Lin Yang Proposal Team: O. Bilsel 1 , B. Hsiao 2 , H. Huang 3 , T. Irving 4 , A. Menzel 5 , L. Pollack 6 , C. Riekel 7 , J. Rubert 8 , H. Tsuruta 9 , L. Yang 10 1 University of Massachusetts, 2 Stony Brook University, 3 Rice University, 4 IIT, 5SLS, 6 Cornell University, 7 European Synchrotron Radiation Facility, 8 NEU, 9 Stanford Synchrotron Radiation Lightsource, 10 Brookhaven National Laboratory TECHNIQUES AND CAPABILITIES APPLICATIONS ADDITIONAL INFORMATION * Energy range 2-20keV using undulator source. Simultaneous SAXS/WAXS to cover 0.003-3Å -1 at 12keV with 1 micron spot size * Time-resolved solution scattering with resolution of (1) microseconds to milliseconds using continuous-flow mixing (5µm x 10µm spot size) and (2) milliseconds using stopped-

25

Biomolecular solution X-ray scattering at the National Synchrotron Light Source  

E-Print Network (OSTI)

In recent years there has been a growing interest in the application of X-ray scattering techniques to biomolecules in solution. At NSLS, a new undulatorbased beamline, X9, has been constructed to address the oversubscribed user demand for X-ray scattering. Beamline X9 has the capability to perform small/wide-angle X-ray scattering (SAXS/WAXS) all in one single instrument. This is accomplished by utilizing a vacuum sample/detector chamber that is an integral part of the SAXS scattering flight path. This vacuum chamber allows a WAXS detector to be positioned at a close distance from the sample, while not interfering with scattered X-rays at small angles from reaching the SAXS detector. A regular training program, the X9 workbench, has also been established to allow users to become familiar with beamline X9 for solution X-ray scattering. Keywords: SAXS; WAXS; beamline; proteins; DNA/RNA. 1.

Marc Allaire; Lin Yang

2010-01-01T23:59:59.000Z

26

Introduction to Neutron and X-Ray Scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

Scattering Studies of Thin Scattering Studies of Thin Polymer Films Introduction to Neutron and X-Ray Scattering Sunil K. Sinha UCSD/LANL Acknowledgements: Prof. R.Pynn( Indiana U.) Prof. M.Tolan (U. Dortmund) Wilhelm Conrad Röntgen 1845-1923 1895: Discovery of X-Rays 1901 W. C. Röntgen in Physics for the discovery of x-rays. 1914 M. von Laue in Physics for x-ray diffraction from crystals. 1915 W. H. Bragg and W. L. Bragg in Physics for crystal structure determination. 1917 C. G. Barkla in Physics for characteristic radiation of elements. 1924 K. M. G. Siegbahn in Physics for x-ray spectroscopy. 1927 A. H. Compton in Physics for scattering of x-rays by electrons. 1936 P. Debye in Chemistry for diffraction of x-rays and electrons in gases.

27

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

DOE Green Energy (OSTI)

An electrochemical in-situ reaction cell for hard X-ray experiments with battery electrodes is described. Applications include the small angle scattering, diffraction, and near-edge spectroscopy of lithium manganese oxide electrodes.

Braun, Artur; Granlund, Eric; Cairns, Elton J.

2003-01-27T23:59:59.000Z

28

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

Proceedings of the 12th International Clay Conference, Bahia Blanca, Argentina, July 22-28, 2001. Gibbs, D. X-ray magnetic scattering. Synchrotron Radiation News...

29

Inelastic X-ray Scattering Reveals Microscopic Transport Properties...  

NLE Websites -- All DOE Office Websites (Extended Search)

Inelastic X-ray Scattering Reveals Microscopic Transport Properties of Molten Aluminum Oxide The transport properties of high-temperature oxide melts are of considerable interest...

30

New Directions in X-ray Scattering - SSRL  

NLE Websites -- All DOE Office Websites (Extended Search)

associated with chemically and radioactively contaminated ground-water. Ability to probe weak scattering from single crystals as function of energy (resonance) and x-ray...

31

Nanostructure of a-Si:H and related alloys by small-angle scattering of neutrons and X-rays: Annual technical progress report: May 22, 1998 -- May 21, 1999  

DOE Green Energy (OSTI)

This report describes work being performed to provide details of the microstructure in high-quality hydrogenated amorphous silicon and related alloys on the nanometer scale. The materials under study are being prepared by state-of-the-art deposition methods, as well as by new and emerging deposition techniques. The purpose is to establish the role of nanostructural features in controlling opto-electronic and photovoltaic properties. The approach centers around the use of the uncommon technique of small-angle scattering of both X-rays (SAXS) and neutrons (SANS). SAXS has already been established as highly sensitive to microvoids and columnar-like microstructure. A major goal of this research is to establish the sensitivity of SANS to the hydrogen nanostructure. Conventional X-ray diffraction techniques are being used to examine medium-range order and microcrystallinity, particularly near the boundary between amorphous and microcrystalline material.

Williamson, D. L.

1999-12-21T23:59:59.000Z

32

Photon Sciences | Beamlines | IXS: Inelastic X-ray Scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

IXS: Inelastic X-ray Scattering IXS: Inelastic X-ray Scattering Poster | Fact Sheet | Preliminary Design Report Scientific Scope Many hot topics related to the high frequency dynamics of condensed matter require both a narrower and steeper resolution function and access to a broader dynamic range than what are currently available. This represents a sort of "no man's land" that falls right in the dynamic gap lying between the high frequency spectroscopies, such as inelastic x-ray scattering (IXS), and the low frequency ones. New IXS spectrometers with improved energy and momentum resolutions would be required to fill this gap. To achieve this goal, a new x-ray optics concept for both the monochromatization and energy analysis of x-rays will be implemented at the NSLS-II Inelastic X-ray Scattering beamline. This solution exploits the

33

Probing Spatial, Electronic Structures with X-ray Scattering, Spectroscopic  

NLE Websites -- All DOE Office Websites (Extended Search)

Probing Spatial, Electronic Structures with X-ray Scattering, Spectroscopic Probing Spatial, Electronic Structures with X-ray Scattering, Spectroscopic Techniques Wednesday, September 5, 2012 - 10:45am SLAC, Bldg. 137, Room 226 Gang Chen Seminar: Structures at atomic scales are traditionally determined through X-ray crystallography that amplifies scattering intensities by introducing spatial periodicity. For amorphous materials and many macromolecules, such as viruses, proteins and biofilms, it is hard to determine structures due to their incapability to crystallize or change of configuration during crystallization. In this talk, I will present the application of X-ray reflectivity and a newly developed fluctuation X-ray scattering technique to study the structures of lipid membranes and randomly oriented nanoparticles. Three different types of domain registrations occurring with

34

ESRF HIGHLIGHTS 2005 X-RAY ABSORPTION AND MAGNETIC SCATTERING  

E-Print Network (OSTI)

96 ESRF HIGHLIGHTS 2005 X-RAY ABSORPTION AND MAGNETIC SCATTERING References [1] C. Antoniak, J to original phenomena. These effects are observed in charge-density wave (CDW) materials. Upon cooling of the screw like dislocation shown in Figure 121b. #12;97 HIGHLIGHTS 2005 ESRF X-RAY ABSORPTION AND MAGNETIC

Paris-Sud 11, Université de

35

Resonant Soft X-Ray Scattering - Combining Structural with Spectroscopic  

NLE Websites -- All DOE Office Websites (Extended Search)

Resonant Soft X-Ray Scattering - Combining Structural with Spectroscopic Resonant Soft X-Ray Scattering - Combining Structural with Spectroscopic Refinement Friday, September 28, 2012 - 10:00am SLAC, Bldg. 137, Room 322 SSRL Presents Kevin Stone X-ray absorption spectroscopy has become an important tool in understanding the electronic structure of materials. Resonant absorption edges in the soft x-ray regime are especially interesting as they allow the study of the lighter elements, such as in organic or organo-metallic substances, as well as important L-edges of the 3d transition metals important in magnetic and oxide systems. Measurements of soft x-ray absorption spectra are inherently surface sensitive, and are plagued by issues such as extinction (in electron yield measurements) or self absorption (in fluorescence yield

36

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

D.F. Inelastic x-ray scattering investigations of lattice dynamics in SmFeAsO1-xFy superconductors. Proceedings of The 9th International Conference on Spectroscopies in Novel...

37

Grazing Incidence Small-Angle X-Ray Scattering Studies of the Synthesis and Growth of CdS Quantum Dots from Constituent Atoms in SiO2 Matrix  

Science Conference Proceedings (OSTI)

Grazing incidence small angle X-ray scattering was applied to study the synthesis and growth of CdS quantum dots (QDs) from Cd and S atoms implanted in SiO{sub 2}. For a dose of 10{sup 17}/cm{sup 2}, the partial synthesis of CdS QDs occurred already during implantation, with only moderate size increase upon subsequent annealing up to T{sub a} = 1073 K. The dynamics of QD synthesis and growth were considerably different for just two times lower dose, where synthesis started only if the implanted samples were annealed at T{sub a} = 773 K or higher, with a strong increase of the size of QDs upon annealing at higher T{sub a}. The results suggest that high-dose implantation followed by low-temperature annealing could lead to better defined sizes and narrower size distributions of QDs.

Desnica, U. V. [R. Boskovic Institute, Zagreb, Croatia; Dubcek, P. [R. Boskovic Institute, Zagreb, Croatia; Desnica-Frankovic, I. D. [R. Boskovic Institute, Zagreb, Croatia; Buljan, M. [R. Boskovic Institute, Zagreb, Croatia; Bernstorff, S. [Sincrotrone Trieste, Basovizza, Italy; White, Clark W [ORNL

2003-01-01T23:59:59.000Z

38

Laser assisted Compton scattering of X-ray photons  

E-Print Network (OSTI)

The Compton scattering of X-ray photons, assisted by a short intense optical laser pulse is discussed. The differential scattering cross section reveals the interesting feature that the main Klein-Nishina line is accompanied by a series of side-lines forming a broad plateau where up to ${\\cal O} (10^3)$ laser photons participate simultaneously in a single scattering event. Due to the non-linear mixing of X-ray and laser photons a frequency dependent rotation of the polarization of the final state photons relative to the scattering plane emerges. A consistent description of the scattering process with short laser pulses requires to work with X-ray pulses. An experimental investigation can be accomplished, e.g., at LCLS or the European XFEL in the near future.

D. Seipt; B. Kampfer

2013-09-09T23:59:59.000Z

39

High performance x-ray anti-scatter grid  

DOE Patents (OSTI)

Disclosed are an x-ray anti-scatter grid for x-ray imaging, particularly for screening mammography, and method for fabricating same, x-rays incident along a direct path pass through a grid composed of a plurality of parallel or crossed openings, microchannels, grooves, or slots etched in a substrate, such as silicon, having the walls of the microchannels or slots coated with a high opacity material, such as gold, while x-rays incident at angels with respect to the slots of the grid, arising from scatter, are blocked. The thickness of the substrate is dependent on the specific application of the grid, whereby a substrate of the grid for mammography would be thinner than one for chest radiology. Instead of coating the walls of the slots, such could be filed with an appropriate liquid, such as mercury. 4 Figs.

Logan, C.M.

1995-05-23T23:59:59.000Z

40

High performance x-ray anti-scatter grid  

DOE Patents (OSTI)

An x-ray anti-scatter grid for x-ray imaging, particularly for screening mammography, and method for fabricating same, x-rays incident along a direct path pass through a grid composed of a plurality of parallel or crossed openings, microchannels, grooves, or slots etched in a substrate, such as silicon, having the walls of the microchannels or slots coated with a high opacity material, such as gold, while x-rays incident at angels with respect to the slots of the grid, arising from scatter, are blocked. The thickness of the substrate is dependent on the specific application of the grid, whereby a substrate of the grid for mammography would be thinner than one for chest radiology. Instead of coating the walls of the slots, such could be filed with an appropriate liquid, such as mercury.

Logan, Clinton M. (Pleasanton, CA)

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Imaging X-ray Thomson Scattering Spectrometer Design and Demonstration  

SciTech Connect

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.

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

2012-05-04T23:59:59.000Z

42

X-ray scattering intensities of water at extreme pressure and temperature  

DOE Green Energy (OSTI)

We have calculated the coherent x-ray scattering intensity of several phases of water at 1500 and 2000 K under high pressure, using ab initio Density Functional Theory (DFT). Our calculations span the molecular liquid, ice VII, and superionic solid phases, including the recently predicted symmetrically hydrogen bonded region of the superionic phase. We show that wide angle x-ray scattering intensity could be used to determine phase boundaries between these high pressure phases, and we compare the results for ice VII and superionic water. We compute simulated spectra and provide new atomic scattering form factors for water at extreme conditions, which take into account frequently neglected changes in ionic charge and electron delocalization. We show that our modifed atomic form factors allow for a nearly exact comaprison to the total x-ray scattering intensities calculated from DFT. Finally, we analyze the effect our new form factors have on determination of the oxygen-oxygen radial distribution function.

Goldman, N; Fried, L E

2007-01-03T23:59:59.000Z

43

Structural characterization of Green River oil-shale at high-pressure using pair distribution function analysis and small angle x-ray scattering.  

Science Conference Proceedings (OSTI)

The compression behavior of a silicate-rich oil shale from the Green River formation in the pressure range 0.0-2.4 GPa was studied using in situ high pressure X-ray pair distribution function (PDF) measurements for the sample contained within a Paris-Edinburgh cell. The real-space local structural information in the PDF, G(r), was used to evaluate the compressibility of the oil shale. Specifically, the pressure-induced reduction in the medium- to long-range atom distances (6-20 {angstrom}) yielded an average sample compressibility corresponding to a bulk modulus of ca. 61-67 GPa. A structural model consisting of a three phase mixture of the principal crystalline oil shale components (quartz, albite and Illite) provided a good fit to the ambient pressure PDF data (R 30.7%). Indeed the features in the PDF beyond 6 {angstrom}, were similarly well fit by a single phase model of the highest symmetry, highly crystalline quartz component.

Locke, D. R.; Chupas, P. J.; Chapman, K. W.; Pugmire, R. J.; Winans, R. E.; Univ. of Utah

2008-01-01T23:59:59.000Z

44

Electronic Structure of Dense Plasmas by X-Ray Scattering  

DOE Green Energy (OSTI)

We present an improved analytical expression for the x-ray dynamic structure factor from a dense plasma which includes the effects of weakly bound electrons. This result can be applied to describe scattering from low to moderate Z plasmas, and it covers the entire range of plasma conditions that can be found in inertial confinement fusion experiments, from ideal to degenerate up to moderately coupled systems. We use our theory to interpret x-ray scattering experiments from solid density carbon plasma and to extract accurate measurements of electron temperature, electron density and charge state. We use our experimental results to validate various equation-of-state models for carbon plasmas.

Gregori, G; Glenzer, S H; Rogers, F J; Pollaine, S M; Froula, D H; Blancard, C; Faussurier, G; Renaudin, P; Kuhlbrodt, S; Redmer, R; Landen, O L

2003-10-07T23:59:59.000Z

45

Neutron and X-Ray Scattering - Argonne National Laboratories, Materials  

NLE Websites -- All DOE Office Websites (Extended Search)

Home Home Neutron and X-Ray Scattering Neutron and X-ray Scattering Science Recent advances in neutron and x-ray scattering instrumentation at major DOE facilities such as the Spallation Neutron Source and Advanced Photon Source provide unprecedented insights into complex phenomena in bulk and interfacial materials. The vision of our group is to harness the complementarity of neutrons and x-rays to study how materials respond on a range of length and time scales to phase competition, so that we can learn to control emergent behavior and generate functional properties in energy-related materials. We use neutrons and x-rays to investigate the structure and dynamics of bulk and interfacial materials with properties that are useful for energy applications, such as superconductivity, magnetism and thermoelectricity. Phase competition can generate or enhance such properties, but it is extremely challenging to characterize fluctuations in the competing order, whether in bulk disordered materials, or artificial heterostructures. Our goal is to utilize efficient techniques that we have been developing for measuring nanoscale phase fluctuations, both static and dynamic, to enable the rational design of new materials for energy within MSD.

46

Neutron and Synchrotron X-Ray Scattering Studies of Superconductors  

Science Conference Proceedings (OSTI)

Superconductors hold the promise for a more stable and efficient electrical grid, but new isotropic, high-temperature superconductors are needed in order to reduce cable manufacturing costs. The effort to understand high-temperature superconductivity, especially in the layered cuprates, provides guidance to the search for new superconductors. Neutron scattering has long provided an important probe of the collective excitations that are involved in the pairing mechanism. For the cuprates, neutron and x-ray diffraction techniques also provide information on competing types of order, such as charge and spin stripes, that appear to be closely connected to the superconductivity. Recently, inelastic x-ray scattering has become competitive for studying phonons and may soon provide valuable information on electronic excitations. Examples of how these techniques contribute to our understanding of superconductivity are presented.

Tranquada,J.M.

2008-09-01T23:59:59.000Z

47

2011 U.S. National School on Neutron and X-ray Scattering  

Science Conference Proceedings (OSTI)

The 13th annual U.S. National School on Neutron and X-ray Scattering was held June 11 to 25, 2011, at both Oak Ridge and Argonne National Laboratories. This school brought together 65 early career graduate students from 56 different universities in the US and provided them with a broad introduction to the techniques available at the major large-scale neutron and synchrotron x-ray facilities. This school is focused primarily on techniques relevant to the physical sciences, but also touches on cross-disciplinary bio-related scattering measurements. During the school, students received lectures by over 30 researchers from academia, industry, and national laboratories and participated in a number of short demonstration experiments at Argonne's Advanced Photon Source (APS) and Oak Ridge's Spallation neutron Source (SNS) and High Flux Isotope Reactor (HFIR) facilities to get hands-on experience in using neutron and synchrotron sources. The first week of this year's school was held at Oak Ridge National Lab, where Lab director Thom Mason welcomed the students and provided a shitorical perspective of the neutron and x-ray facilities both at Oak Ridge and Argonne. The first few days of the school were dedicated to lectures laying out the basics of scattering theory and the differences and complementarity between the neutron and x-ray probes given by Sunil Sinha. Jack Carpenter provided an introduction into how neutrons are generated and detected. After this basic introduction, the students received lectures each morning on specific techniques and conducted demonstration experiments each afternoon on one of 15 different instruments at either the SNS or HFIR. Some of the topics covered during this week of the school included inelastic neutron scattering by Bruce Gaulin, x-ray and neutron reflectivity by Chuck Majkrazak, small-angle scattering by Volker Urban, powder diffraction by Ashfia Huq and diffuse scattering by Gene Ice.

Lang, Jonathan [Argonne National Laboratory (ANL); te Vethuis, Suzanne [Argonne National Laboratory (ANL); Ekkebus, Allen E [ORNL; Chakoumakos, Bryan C [ORNL; Budai, John D [ORNL

2012-01-01T23:59:59.000Z

48

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

- Brookhaven National Laboratory, Upton, NY Beamline X1A2 - Soft x-ray diffraction and nano-imaging Beamline X17 - X-ray powder diffraction Beamline X22C - Resonant x-ray...

49

Large-scale Nanostructure Simulations from X-ray Scattering Data On Graphics Processor Clusters  

Science Conference Proceedings (OSTI)

X-ray scattering is a valuable tool for measuring the structural properties of materialsused in the design and fabrication of energy-relevant nanodevices (e.g., photovoltaic, energy storage, battery, fuel, and carbon capture andsequestration devices) that are key to the reduction of carbon emissions. Although today's ultra-fast X-ray scattering detectors can provide tremendousinformation on the structural properties of materials, a primary challenge remains in the analyses of the resulting data. We are developing novelhigh-performance computing algorithms, codes, and software tools for the analyses of X-ray scattering data. In this paper we describe two such HPCalgorithm advances. Firstly, we have implemented a flexible and highly efficient Grazing Incidence Small Angle Scattering (GISAXS) simulation code based on theDistorted Wave Born Approximation (DWBA) theory with C++/CUDA/MPI on a cluster of GPUs. Our code can compute the scattered light intensity from any givensample in all directions of space; thus allowing full construction of the GISAXS pattern. Preliminary tests on a single GPU show speedups over 125x compared tothe sequential code, and almost linear speedup when executing across a GPU cluster with 42 nodes, resulting in an additional 40x speedup compared to usingone GPU node. Secondly, for the structural fitting problems in inverse modeling, we have implemented a Reverse Monte Carlo simulation algorithm with C++/CUDAusing one GPU. Since there are large numbers of parameters for fitting in the in X-ray scattering simulation model, the earlier single CPU code required weeks ofruntime. Deploying the AccelerEyes Jacket/Matlab wrapper to use GPU gave around 100x speedup over the pure CPU code. Our further C++/CUDA optimization deliveredan additional 9x speedup.

Sarje, Abhinav; Pien, Jack; Li, Xiaoye; Chan, Elaine; Chourou, Slim; Hexemer, Alexander; Scholz, Arthur; Kramer, Edward

2012-01-15T23:59:59.000Z

50

Air-core grid for scattered x-ray rejection  

DOE Patents (OSTI)

The invention is directed to a grid used in x-ray imaging applications to block scattered radiation while allowing the desired imaging radiation to pass through, and to process for making the grid. The grid is composed of glass containing lead oxide, and eliminates the spacer material used in prior known grids, and is therefore, an air-core grid. The glass is arranged in a pattern so that a large fraction of the area is open allowing the imaging radiation to pass through. A small pore size is used and the grid has a thickness chosen to provide high scatter rejection. For example, the grid may be produced with a 200 {micro}m pore size, 80% open area, and 4 mm thickness. 2 figs.

Logan, C.M.; Lane, S.M.

1995-10-03T23:59:59.000Z

51

Air-core grid for scattered x-ray rejection  

DOE Patents (OSTI)

The invention is directed to a grid used in x-ray imaging applications to block scattered radiation while allowing the desired imaging radiation to pass through, and to process for making the grid. The grid is composed of glass containing lead oxide, and eliminates the spacer material used in prior known grids, and is therefore, an air-core grid. The glass is arranged in a pattern so that a large fraction of the area is open allowing the imaging radiation to pass through. A small pore size is used and the grid has a thickness chosen to provide high scatter rejection. For example, the grid may be produced with a 200 .mu.m pore size, 80% open area, and 4 mm thickness.

Logan, Clinton M. (Pleasanton, CA); Lane, Stephen M. (Oakland, CA)

1995-01-01T23:59:59.000Z

52

Large-scale Nanostructure Simulations from X-ray Scattering Data On Graphics Processor Clusters  

E-Print Network (OSTI)

X-ray Scattering Data On Graphics Processor Clusters Abhinavaccelerators. General purpose graphics processors o?er ?nethe form factors on graphics processors. Form Factor Kernel

Sarje, Abhinav

2012-01-01T23:59:59.000Z

53

K-alpha conversion efficiency measurments for x-ray scattering in inertial confinement fusion plasmas  

SciTech Connect

The conversion efficiency of ultra short-pulse laser radiation to K-{alpha} x-rays has been measured for various chlorine-containing targets to be used as x-ray scattering probes of dense plasmas. The spectral and temporal properties of these sources will allow spectrally-resolved x-ray scattering probing with picosecond temporal resolution required for measuring the plasma conditions in inertial confinement fusion experiments. Simulations of x-ray scattering spectra from these plasmas show that fuel capsule density, capsule ablator density, and shock timing information may be inferred.

Kritcher, A L; Neumayer, P; Urry, M K; Robey, H; Niemann, C; Landen, O L; Morse, E; Glenzer, S H

2006-11-21T23:59:59.000Z

54

Neutron and X-ray Scattering Investigations of Microscopic Energy ...  

Science Conference Proceedings (OSTI)

A Case Study in Future Energy Challenges: Towards In Situ Hard X-ray Microscopy of ... of Crystal Structure and Domain Character in Lead Free Piezoceramics.

55

Staff at sector 30, inelastic x-ray scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

Status and Schedule Safety and Training Divisions APS Engineering Support Division AES Groups Accelerator Systems Division ASD Groups X-ray Science Division XSD Groups...

56

Direct and bulk-scattered forward-shock emissions: sources of X-ray afterglow diversity  

E-Print Network (OSTI)

I describe the modifications to the standard forward-shock model required to account for the X-ray light-curve features discovered by Swift in the early afterglow emission and propose that a delayed, pair-enriched, and highly relativistic outflow, which bulk-scatters the forward-shock synchrotron emission, yields sometimes a brighter X-ray emission, producing short-lived X-ray flares, X-ray light-curve plateaus ending with chromatic breaks, and fast post-plateau X-ray decays.

A. Panaitescu

2008-02-09T23:59:59.000Z

57

The Role of Surface X-ray Scattering in Electrocatalysis  

NLE Websites -- All DOE Office Websites (Extended Search)

3 3 N. M. Markovi , LBNL and C. A. Lucas, University of Liverpool Ecological and political realities have moved discussions of, and advances in, fuel cell technology into mainstream public awareness. Electrocatalysis, the science of modifying the overall rates of electrochemical reactions so that selectivity, yield and efficiency are maximized, is the work from which those advances spring. Studies in electrocatalysis have resulted in highly selective multicomponent gas mixture sensors, human blood component sensors, new electrocatalysts for oxidation/reduction of inorganic and organic pollutants in air and water, as well as better electrocatalysts for the fuel cell conversion of renewable and fossil fuels to electrical work. Studies of the mechanisms by which these catalysts operate have been advanced through development of in-situ surface x-ray scattering (SXS) techniques. SXS capabilities at SSRL were recently used to investigate the interface structure of an ultrathin COad (adsorbed carbon monoxide) overlayer on platinum. This work has elevated the macroscopic description of the COad state at the solid-liquid interface to a microscopic level and enabled the relation between the reactivity and the interfacial structure of COad/Pt to be understood.

58

Magnetism studies using resonant, coherent, x-ray scattering...  

NLE Websites -- All DOE Office Websites (Extended Search)

10:00am SLAC, Bldg. 137, Room 226 Keoki Seu Seminar: With the advent of free electron lasers there has been interest in using coherent x-rays to probe condensed matter systems....

59

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

Ocko, B.M., Wen, K., Maoz, R., Cohen, H., and Sagiv, J. Non-destructive chemical modification of a preassembled silane multilayer: structural study by combined FTIR, x-ray...

60

Protein folding and protein metallocluster studies using synchrotron small angler X-ray scattering  

SciTech Connect

Proteins, biological macromolecules composed of amino-acid building blocks, possess unique three dimensional shapes or conformations which are intimately related to their biological function. All of the information necessary to determine this conformation is stored in a protein`s amino acid sequence. The problem of understanding the process by which nature maps protein amino-acid sequences to three-dimensional conformations is known as the protein folding problem, and is one of the central unsolved problems in biophysics today. The possible applications of a solution are broad, ranging from the elucidation of thousands of protein structures to the rational modification and design of protein-based drugs. The scattering of X-rays by matter has long been useful as a tool for the characterization of physical properties of materials, including biological samples. The high photon flux available at synchrotron X-ray sources allows for the measurement of scattering cross-sections of dilute and/or disordered samples. Such measurements do not yield the detailed geometrical information available from crystalline samples, but do allow for lower resolution studies of dynamical processes not observable in the crystalline state. The main focus of the work described here has been the study of the protein folding process using time-resolved small-angle x-ray scattering measurements. The original intention was to observe the decrease in overall size which must accompany the folding of a protein from an extended conformation to its compact native state. Although this process proved too fast for the current time-resolution of the technique, upper bounds were set on the probable compaction times of several small proteins. In addition, an interesting and unexpected process was detected, in which the folding protein passes through an intermediate state which shows a tendency to associate. This state is proposed to be a kinetic molten globule folding intermediate.

Eliezer, D.

1994-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Photon Sciences | Beamlines | CSX: Coherent Soft X-ray Scattering and  

NLE Websites -- All DOE Office Websites (Extended Search)

CSX: Coherent Soft X-ray Scattering and polarization CSX: Coherent Soft X-ray Scattering and polarization X-Ray 1 Poster | X-Ray 2 Poster | Fact Sheet | Preliminary Design Report Scientific Scope The Coherent Soft X-ray Scattering and Polarization (CSX) beamline design (source and optics) has been optimized to the NSLS-II parameters to provide the highest possible flux for experiments requiring either high coherence or full control of the polarization. Beamline Description The CSX beamline will be served by two identical EPU49 sources. Both EPUs are planned to operate in a canted geometry with opposite circular polarization for fast polarization switching experiments at the full polarization control (PC) branch. The EPUs will also be able to operate "phased" as a single device for high coherent flux experiments at the

62

X Ray Scattering | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

X Ray Scattering X Ray Scattering Materials Sciences and Engineering (MSE) Division MSE Home About Research Areas Energy Frontier Research Centers (EFRCs) DOE Energy Innovation Hubs BES Funding Opportunities The Computational Materials and Chemical Sciences Network (CMCSN) Theoretical Condensed Matter Physics Scientific Highlights Reports and Activities Principal Investigators' Meetings BES Home Research Areas X Ray Scattering Print Text Size: A A A RSS Feeds FeedbackShare Page This activity supports basic research on the fundamental interactions of photons with matter to achieve an understanding of atomic, electronic, and magnetic structures and excitations and their relationships to materials properties. The main emphasis is on x-ray scattering, spectroscopy, and imaging research, primarily at major BES-supported user facilities.

63

Resonant Soft X-Ray Scattering of Tri-Block Copolymers  

NLE Websites -- All DOE Office Websites (Extended Search)

previous experiments have been few. Now, an international team from the United States, Korea, and Japan has succeeded in combining resonant soft x-ray scattering (RSoXS) at ALS...

64

Synchrotron-based coherent scatter x-ray projection imaging using an array of monoenergetic pencil beams  

SciTech Connect

Traditional projection x-ray imaging utilizes only the information from the primary photons. Low-angle coherent scatter images can be acquired simultaneous to the primary images and provide additional information. In medical applications scatter imaging can improve x-ray contrast or reduce dose using information that is currently discarded in radiological images to augment the transmitted radiation information. Other applications include non-destructive testing and security. A system at the Canadian Light Source synchrotron was configured which utilizes multiple pencil beams (up to five) to create both primary and coherent scatter projection images, simultaneously. The sample was scanned through the beams using an automated step-and-shoot setup. Pixels were acquired in a hexagonal lattice to maximize packing efficiency. The typical pitch was between 1.0 and 1.6 mm. A Maximum Likelihood-Expectation Maximization-based iterative method was used to disentangle the overlapping information from the flat panel digital x-ray detector. The pixel value of the coherent scatter image was generated by integrating the radial profile (scatter intensity versus scattering angle) over an angular range. Different angular ranges maximize the contrast between different materials of interest. A five-beam primary and scatter image set (which had a pixel beam time of 990 ms and total scan time of 56 min) of a porcine phantom is included. For comparison a single-beam coherent scatter image of the same phantom is included. The muscle-fat contrast was 0.10 {+-} 0.01 and 1.16 {+-} 0.03 for the five-beam primary and scatter images, respectively. The air kerma was measured free in air using aluminum oxide optically stimulated luminescent dosimeters. The total area-averaged air kerma for the scan was measured to be 7.2 {+-} 0.4 cGy although due to difficulties in small-beam dosimetry this number could be inaccurate.

Landheer, Karl [Ottawa Medical Physics Institute and Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa K1S 5B6 (Canada); Johns, Paul C. [Ottawa Medical Physics Institute and Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa K1S 5B6 (Canada); Department of Radiology, University of Ottawa (Canada)

2012-09-15T23:59:59.000Z

65

Anomalous and resonance small angle scattering  

SciTech Connect

Significant changes in the small angle scattered intensity can be induced by making measurements with radiation close to an absorption edge of an appropriate atomic species contained in the sample. These changes can be related quantitatively to the real and imaginary anomalous dispersion terms for the scattering factor (x-rays) or scattering length (neutrons). The physics inherent in these anomalous dispersion terms is first discussed before considering how they enter the relevant scattering theory. Two major areas of anomalous scattering research have emerged; macromolecules in solution and unmixing of metallic alloys. Research in each area is reviewed, illustrating both the feasibility and potential of these techniques. All the experimental results reported to date have been obtained with x-rays. However, it is pointed out that the formalism is the same or the analogue experiment with neutrons, and a number of suitable isotopes exist which exhibit resonance in an accessible range of energy. Potential applications of resonance small-angle neutron scatterings are discussed. 8 figs.

Epperson, J.E.; Thiyagarajan, P.

1987-11-01T23:59:59.000Z

66

Anomalous and resonance small angle scattering: Revision  

SciTech Connect

Significant changes in the small angle scattered intensity can be induced by making measurements with radiation close to an absorption edge of an appropriate atomic species contained in the sample. These changes can be related quantitatively to the real and imaginary anomalous dispersion terms for the scattering factor (x-rays) or scattering length (neutrons). The physics inherent in these anomalous dispersion terms is first discussed before considering how they enter the relevant scattering theory. Two major areas of anomalous scattering research have emerged; macromolecules in solution and unmixing of metallic alloys. Research in each area is reviewed, illustrating both the feasibility and potential of these techniques. All the experimental results reported to date have been obtained with x-rays. However, it is pointed out that the formalism is the same for the analogue experiment with neutrons, and a number of suitable isotopes exist which exhibit resonance in an accessible range of energy. Potential applications of resonance small angle neutron scatterings are discussed. 54 refs., 8 figs., 1 tab.

Epperson, J.E.; Thiyagarajan, P.

1987-11-01T23:59:59.000Z

67

Entangled valence electron-hole dynamics revealed by stimulated attosecond x-ray Raman scattering  

SciTech Connect

We show that broadband x-ray pulses can create wavepackets of valence electrons and holes localized in the vicinity of a selected atom (nitrogen, oxygen or sulfur in cysteine) by resonant stimulated Raman scattering. The subsequent dynamics reveals highly correlated motions of entangled electrons and hole quasiparticles. This information goes beyond the time-dependent total charge density derived from x-ray diffraction.

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

2012-09-06T23:59:59.000Z

68

THE HARD X-RAY SPECTRUM OF NGC 1365: SCATTERED LIGHT, NOT BLACK HOLE SPIN  

SciTech Connect

Active galactic nuclei (AGNs) show excess X-ray emission above 10 keV compared with extrapolation of spectra from lower energies. Risaliti et al. have recently attempted to model the hard X-ray excess in the type 1.8 AGN NGC 1365, concluding that the hard excess most likely arises from Compton-scattered reflection of X-rays from an inner accretion disk close to the black hole. Their analysis disfavored a model in which the hard excess arises from a high column density of circumnuclear gas partially covering a primary X-ray source, despite such components being required in the NGC 1365 data below 10 keV. Using a Monte Carlo radiative transfer approach, we demonstrate that this conclusion is invalidated by (1) use of slab absorption models, which have unrealistic transmission spectra for partial covering gas, (2) neglect of the effect of Compton scattering on transmitted spectra, and (3) inadequate modeling of the spectrum of scattered X-rays. The scattered spectrum is geometry-dependent and, for high global covering factors, may dominate above 10 keV. We further show that, in models of circumnuclear gas, the suppression of the observed hard X-ray flux by reprocessing may be no larger than required by the ''light bending'' model invoked for inner disk reflection, and the expected emission line strengths lie within the observed range. We conclude that the time-invariant ''red wing'' in AGN X-ray spectra is probably caused by continuum transmitted through and scattered from circumnuclear gas, not by highly redshifted line emission, and that measurement of black hole spin is not possible.

Miller, L. [Department of Physics, Oxford University, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Turner, T. J. [Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250 (United States)

2013-08-10T23:59:59.000Z

69

Educational Programs - National School on Neutron & X-ray Scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

and national laboratories, will include basic tutorials on the principles of scattering theory and the characteristics of the sources, as well as seminars on the application of...

70

X-ray Thomson scattering for partially ionized plasmas including the effect of bound levels  

E-Print Network (OSTI)

X-ray Thomson scattering is being developed as a method to measure the temperature, electron density, and ionization state of high energy density plasmas such as those used in inertial confinement fusion. Most experiments are currently done at large laser facilities that can create bright X-ray sources, however the advent of the X-ray free electron laser (X-FEL) provides a new bright source to use in these experiments. One challenge with X-ray Thomson scattering experiments is understanding how to model the scattering for partially ionized plasmas in order to include the contributions of the bound electrons in the scattered intensity. In this work we take the existing models of Thomson scattering that include elastic ion-ion scattering and the electron-electron plasmon scattering and add the contribution of the bound electrons in the partially ionized plasmas. We validated our model by analyzing existing beryllium experimental data. We then consider several higher Z materials such as Cr and predict the existe...

Nilsen, J; Cheng, K T

2013-01-01T23:59:59.000Z

71

SOFT INELASTIC X-RAY SCATTERING (SIX) Group Leader: Ignace Jarrige  

NLE Websites -- All DOE Office Websites (Extended Search)

INELASTIC X-RAY SCATTERING (SIX) INELASTIC X-RAY SCATTERING (SIX) Group Leader: Ignace Jarrige 1 Proposal Team: D. Arena 1 , A. Baron 2 , Y. Cai 1 , Y.-D. Chuang 3 , F. de Groot 4 , J. Guo 3 , J.P. Hill 1 , S. Hulbert 1 , C. McGuinness 5 , R. Reininger 9 , J.E. Rubenson 6 , C. Sanchez-Hanke 1 , T. Schmitt 7 , K. Smith 8 1 Brookhaven National Laboratory, 2 SPring-8, 3 Lawrence Berkeley Laboratory, 4 Utrecht University, 5 Trinity College Dublin, 6 Uppsala University, 7 Paul Scherrer Institute, 8 Boston University, 9 Argonne National Laboratory TECHNIQUE AND CAPABILITIES APPLICATIONS ADDITIONAL INFORMATION * Resonant inelastic x-ray scattering (RIXS) at unprecedented resolution (10 meV @ 1000 eV) to revolutionize study of low energy excitations in many important materials. * Continuously tunable momentum transfer (q) to study the

72

SSRL School 2007 on Hard X-ray Scattering Techniques in MES  

NLE Websites -- All DOE Office Websites (Extended Search)

May 15-17, 2007 SSRL School on Hard X-ray Scattering Techniques in Materials and Environmental Sciences Group photo taken at the SSRL School on Hard X-ray Scattering Techniques in Materials and Environmental Sciences. A large, printable version of this group image is available via clicking on the image. Overview: Modern synchrotron-based X-ray scattering (SR-XRS) techniques offer the ability to probe nano- and atomic-scale structures and order/disorder relationships that critically govern the properties of advanced technological and environmental materials. The high collimation, intensity, and tunability of SR allow the investigation of a wide range of materials, including thin films and interfaces, nanoparticles, amorphous materials, solutions, hydrated and disordered bacteriogenic minerals,

73

Electronic Structure Measurement of Solid Density Plasmas using X-Ray Scattering  

DOE Green Energy (OSTI)

We present an improved analytical expression for the x-ray dynamic structure factor from a dense plasma which includes the effects of weakly bound electrons. This result can be applied to describe scattering from low to moderate Z plasmas, and it covers the entire range of plasma conditions that can be found in inertial confinement fusion experiments, from ideal to degenerate up to moderately coupled systems. We use our theory to interpret x-ray scattering experiments from solid density carbon plasma and to extract accurate measurements of electron temperature, electron density and charge state. We use our experimental results to validate various equation-of-state models for carbon plasmas.

Gregori, G; Glenzer, S H; Rogers, F J; Landen, O L; Blancard, C; Faussurier, G; Renaudin, P; Kuhlbrodt, S; Redmer, R

2003-08-23T23:59:59.000Z

74

Investigation of the Electronic Structure of Solid Density Plasmas by X-Ray Scattering  

DOE Green Energy (OSTI)

We present an improved analytical expression for the x-ray dynamic structure factor from a dense plasma which includes the effects of weakly bound electrons. This result can be applied to describe scattering from low to moderate Z plasmas, and it covers the entire range of plasma conditions that can be found in inertial confinement fusion experiments, from ideal to degenerate up to moderately coupled systems. We use our theory to interpret x-ray scattering experiments from solid density carbon plasma and to extract accurate measurements of electron temperature, electron density and charge state. We use our experimental results to validate various equation-of-state models for carbon plasmas.

Gregori, G; Glenzer, S H; Forest, F J; Kuhlbrodt, S; Redmer, R; Faussurier, G; Blancard, C; Renaudin, P; Landen, O L

2003-05-19T23:59:59.000Z

75

Observations of non-collective x-ray scattering in warm dense carbon plasma  

Science Conference Proceedings (OSTI)

An experiment for observing the spectrally resolved non-collective x-ray scattering in warm dense carbon plasma is presented in this paper. The experiment used Ta M-band x-rays to heat a foamed carbon cylinder sample isochorically and measured the scattering spectrum with a HOPG crystal spectrometer. The spectrum was compared with the calculation results using a Born-Mermin-approximation model. The best fitting was found at an electron temperature of T{sub e}=34 eV and an electron density of n{sub e}=1.6 Multiplication-Sign 10{sup 23}cm{sup -3}.

Bao Lihua [Research Center of Laser Fusion, China Academy of Engineering Physics, P. O. Box 919-981, Mianyang 621900 (China); Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Zhang Jiyan; Zhao Yang; Ding Yongkun [Research Center of Laser Fusion, China Academy of Engineering Physics, P. O. Box 919-981, Mianyang 621900 (China); Zhang Xiaoding [Research Center of Laser Fusion, China Academy of Engineering Physics, P. O. Box 919-981, Mianyang 621900 (China); University of Science and Technology of China, Hefei 230026 (China)

2012-12-15T23:59:59.000Z

76

High energy resolution inelastic x-ray scattering at the SRI-CAT  

SciTech Connect

This report is a combination of vugraphs and two papers. The vugraphs give information on the beamline at the APS for IXS and the science addressable by IXS. They also cover the 10 milli-eV resolution spectrometer and the 200 milli-eV resolution spectrometer. The first paper covers the performance of the focusing Ge(444) backscattering analyzers for the inelastic x-ray scattering. The second paper discusses inelastic x-ray scattering from TiC and Ti single crystals.

Macrander, A.T.

1996-08-01T23:59:59.000Z

77

X-ray Scattering Reveals Unusual Growth of Lead on Silicon  

NLE Websites -- All DOE Office Websites (Extended Search)

X-ray Scattering Reveals Unusual Growth of Lead on Silicon X-ray Scattering Reveals Unusual Growth of Lead on Silicon Most thin films grow on substrates in only three ways: layer by layer, formation of atomic islands, or layers followed by islands. The particular growth mode that a given material will follow crucially depends on the relative magnitudes of the surface energy of the film versus the interfacial energy of the film on the substrate. Recently, a team of researchers from the University of Illinois, Academica Sinica in Taiwan, Georgia Tech, and the City University of Hong Kong has discovered a remarkable anomaly. By means of real-time x-ray scattering measurements, the researchers found that lead films grown on silicon adopt a completely novel pattern of growth. X-ray diffraction images taken with a CCD camera during growth of Pb films on Si(111). The interference fringes yield information about island height and layer thickness. Fig. 1. X-ray diffraction images taken with a CCD camera during growth of Pb films on Si(111). The interference fringes yield information about island height and layer thickness.

78

Uv Thomson scattering from x-ray laser plasmas  

SciTech Connect

Plasmas produced by irradiating massive carbon targets with a 1.064 {mu}m, 1.5 ns laser pulse at incident energies of {approximately}100 J have been investigated. UV thermal Thomson scattering was used to obtain the electron and ion temperatures, as well as drift velocities. The electron density was obtained by optical interferometry. The results are compared to hydrodynamic computer modeling. 6 refs., 6 figs.

La Fontaine, B.; Baldis, H.A.; Villeneuve, D.M.; Bernard, J.E.; Enright, G.D. (National Research Council of Canada, Ottawa, ON (Canada)); Rosen, M.D.; Young, P.E.; Matthews, D.L. (Lawrence Livermore National Lab., CA (USA))

1991-01-03T23:59:59.000Z

79

Resonant Soft X-Ray Scattering of Tri-Block Copolymers  

NLE Websites -- All DOE Office Websites (Extended Search)

Resonant Soft X-Ray Scattering Resonant Soft X-Ray Scattering of Tri-Block Copolymers Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print Wednesday, 30 May 2012 00:00 In principle, tri-block copolymers (tri-BCPs), consisting of three chemically distinct polymers covalently joined together at the ends of each polymer chain, can serve as scaffolds and templates for fabricating a vast number of nanostructures. While quantitatively understanding the details of the morphology and the manner in which the different blocks interact with surfaces and interfaces is critical to success, previous experiments have been few. Now, an international team from the United States, Korea, and Japan has succeeded in combining resonant soft x-ray scattering (RSoXS) at ALS Beamline 11.0.1 with transmission electron microscopy tomography (TEMT) and other techniques to unambiguously determine morphologies comprising two nested hexagonally packed arrays of nanoscopic, cylindrical microdomains in the bulk and a core-shell nanostructure in a thin film. Not only has this work revealed a new phase of ABC tri-block copolymer with complicated morphology, it has illustrated the importance of RSoXS as a unique, powerful tool for examining complex, multi-component systems that could not be characterized with conventional methods.

80

Determination of phonon dispersion relations by X-ray thermal diffuse scattering  

SciTech Connect

Thermal diffuse scattering (TDS) of X-rays from crystals contains information on phonons. This paper reviews the general theory of TDS and some recent experiments aimed at further developing TDS into a useful and efficient method for studying phonon dispersion relations.

Xu, R.; Chiang, T.-C. (UIUC)

2010-07-20T23:59:59.000Z

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81

Soft X-Ray Thomson Scattering in Warm Dense Hydrogen at FLASH  

DOE Green Energy (OSTI)

We present collective Thomson scattering with soft x-ray free electron laser radiation as a method to track the evolution of warm dense matter plasmas with {approx}200 fs time resolution. In a pump-probe scheme an 800 nm laser heats a 20 {micro}m hydrogen droplet to the plasma state. After a variable time delay in the order of ps the plasma is probed by an x-ray ultra violet (XUV) pulse which scatters from the target and is recorded spectrally. Alternatively, in a self-Thomson scattering experiment, a single XUV pulse heats the target while a portion of its photons are being scattered probing the target. From such inelastic x-ray scattering spectra free electron temperature and density can be inferred giving insight on relaxation time scales in plasmas as well as the equation of state. We prove the feasibility of this method in the XUV range utilizing the free electron laser facility in Hamburg, FLASH. We recorded Thomson scattering spectra for hydrogen plasma, both in the self-scattering and in the pump-probe mode using optical laser heating.

Faustlin, R R; Toleikis, S; Bornath, T; Doppner, T; Dusterer, S; Forster, E; Fortmann, C; Glenzer, S H; Gode, S; Gregori, G; Irsig, R; Laarmann, T; Lee, H J; Li, B; Meiwes-Broer, K; Mithen, J; Przystawik, A; Redlin, H; Redmer, R; Reinholz, H; Ropke, G; Tavella, F; Thiele, R; Tiggesbaumker, J; Uschmann, I; Zastrau, U; Tschentscher, T

2009-07-15T23:59:59.000Z

82

Electrochemically adsorbed Pb on Ag (111) studied with grazing- incidence x-ray scattering  

SciTech Connect

Grazing-incidence x-ray scattering studies of the evolution of electrochemically deposited layers of lead on silver (111) as a function of applied electrochemical potential are presented. Measurements were made with the adsorbed layers in contact with solution in a specially designed sample cell. The observed lead structures are a function of the applied potential and range from an incommensurate monolayer, resulting from underpotential deposition, to randomly oriented polycrystalline bulk lead, resulting from lower deposition potentials. These early experiments demonstrate the ability of in situ x-ray diffraction measurements to determine structures associated with electrochemical deposition. 6 refs., 4 figs.

Kortright, J.B.; Ross, P.N.; Melroy, O.R.; Toney, M.F.; Borges, G.L.; Samant, M.G.

1989-04-01T23:59:59.000Z

83

Soft x-ray scattering using FEL radiation for probing near-solid density plasmas at few electronvolt temperatures  

DOE Green Energy (OSTI)

We report on soft x-ray scattering experiments on cryogenic hydrogen and simple metal targets. As a source of intense and ultrashort soft x-ray pulses we have used free-electron laser radiation at 92 eV photon energy from FLASH at DESY, Hamburg. X-ray pulses with energies up to 100 {micro}J and durations below 50 fs provide interaction with the target leading simultaneously to plasma formation and scattering. Experiments exploiting both of these interactions have been carried out, using the same experimental setup. Firstly, recording of soft x-ray inelastic scattering from near-solid density hydrogen plasmas at few electronvolt temperatures confirms the feasibility of this diagnostics technique. Secondly, the soft x-ray excitation of few electronvolt solid-density plasmas in simple metals could be studied by recording soft x-ray line and continuum emission integrated over emission times from fs to ns.

Toleikis, S; Faustlin, R R; Cao, L; Doppner, T; Dusterer, S; Forster, E; Fortmann, C; Glenzer, S H; Gode, S; Gregori, G; Irsig, R; Laarmann, T; Lee, H J; Li, B; Meiwes-Broer, K; Przystawik, A; Radcliffe, P; Redmer, R; Tavella, F; Thiele, R; Tiggesbaumker, J; Truong, N X; Uschmann, I; Zastrau, U; Tschentscher, T

2009-03-03T23:59:59.000Z

84

Theme Article - Time-Resolved X-Ray Scattering from Coherent Excitations in Solids  

SciTech Connect

Recent advances in pulsed x-ray sources have opened up new opportunities to study the dynamics of matter directly in the time domain with picosecond to femtosecond resolution. In this article, we present recent results from a variety of ultrafast sources on time-resolved x-ray scattering from elementary excitations in periodic solids. A few representative examples are given on folded acoustic phonons, coherent optical phonons, squeezed phonons, and polaritons excited by femtosecond lasers. Next-generation light sources, such as the x-ray-free electron laser, will lead to improvements in coherence, flux, and pulse duration. These experiments demonstrate potential opportunities for studying matter far from equilibrium on the fastest time scales and shortest distances that will be available in the coming years.

Trigo, Mariano; Reis, David (SLAC)

2010-10-22T23:59:59.000Z

85

Theoretical Model and Interpretation of Dense Plasma X-Ray Thomson Scattering  

Science Conference Proceedings (OSTI)

The authors present analytical expressions for the dynamic structure factor, or form factor S(k,{omega}), which is the quantity describing the inelastic x-ray cross section from a dense plasma or a simple liquid. The results, based on the random phase approximation (RPA) for the treatment on the charged particle coupling, can be applied to describe scattering from either weakly coupled classical plasmas or degenerate electron liquids. The form factor correctly reproduces the Compton energy downshift and the usual Fermi-Dirac electron velocity distribution for S(k,{omega}) in the case of a cold degenerate plasma. the usual concept of scattering parameter is also reinterpreted for the degenerate case in order to include the effect of the Thomas-Fermi screening. The results shown in this work can be applied to interpreting x-ray scattering in warm dense plasmas occurring in inertial confinement fusion experiments or inside the interior of planets.

Gregori, G; Landen, O; Hicks, D; Pasley, J; Collins, G; Celliers, P; Bastea, M; Glenzer, S

2002-04-03T23:59:59.000Z

86

X-ray Thomson scattering measurements from shock-compressed deuterium  

Science Conference Proceedings (OSTI)

X-ray Thomson scattering has recently been shown to be an effective method of diagnosing a variety of high energy density plasma conditions. We apply this powerful technique to the widely studied problem of shock-compressed liquid deuterium. The behavior of deuterium under extreme conditions has received considerable attention due to its central role in models of giant planets and the importance of the high-pressure insulator-metal transition. We have used spectrally resolved x-ray scattering from electron-plasma waves to perform microscopic observations of ionization during compression. In these experiments, a single shock was launched in cryogenic deuterium reaching compressions of 3x. The 2 keV Ly-{alpha} line in silicon was used as an x-ray source in a forward scattering geometry. In addition to elastic scattering from tightly bound electrons, this low probe energy accessed the collective plasmon oscillations of delocalized electrons. Inelastic scattering from the plasmons allowed accurate measurements of the free electron density through the spectral position of the resonance and provided an estimate of the temperature through its ratio with the elastic feature. Combined with velocity interferometry from the reflective shock front, this lead to a direct determination of the ionization state. We compare the measured ionization conditions with computational models. Additionally, we discuss the possibility of using this technique to determine electrical conductivity and to directly observe pressure-induced molecular dissociation along the Hugoniot.

Davis, P.; Doeppner, T.; Rygg, J. R.; Fortmann, C.; Unites, W.; Salmonson, J.; Collins, G. W.; Landen, O. L.; Falcone, R. W.; Glenzer, S. H. [University of California, Berkeley. Berkeley, CA, 94720 (United States); Lawrence Livermore National Laboratory. Livermore, CA 94551 (United States); University of California, Berkeley. Berkeley, CA, 94720 (United States)

2012-05-25T23:59:59.000Z

87

Resonant Soft X-Ray Scattering of Tri-Block Copolymers  

NLE Websites -- All DOE Office Websites (Extended Search)

Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print In principle, tri-block copolymers (tri-BCPs), consisting of three chemically distinct polymers covalently joined together at the ends of each polymer chain, can serve as scaffolds and templates for fabricating a vast number of nanostructures. While quantitatively understanding the details of the morphology and the manner in which the different blocks interact with surfaces and interfaces is critical to success, previous experiments have been few. Now, an international team from the United States, Korea, and Japan has succeeded in combining resonant soft x-ray scattering (RSoXS) at ALS Beamline 11.0.1 with transmission electron microscopy tomography (TEMT) and other techniques to unambiguously determine morphologies comprising two nested hexagonally packed arrays of nanoscopic, cylindrical microdomains in the bulk and a core-shell nanostructure in a thin film. Not only has this work revealed a new phase of ABC tri-block copolymer with complicated morphology, it has illustrated the importance of RSoXS as a unique, powerful tool for examining complex, multi-component systems that could not be characterized with conventional methods.

88

Resonant Soft X-Ray Scattering of Tri-Block Copolymers  

NLE Websites -- All DOE Office Websites (Extended Search)

Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print In principle, tri-block copolymers (tri-BCPs), consisting of three chemically distinct polymers covalently joined together at the ends of each polymer chain, can serve as scaffolds and templates for fabricating a vast number of nanostructures. While quantitatively understanding the details of the morphology and the manner in which the different blocks interact with surfaces and interfaces is critical to success, previous experiments have been few. Now, an international team from the United States, Korea, and Japan has succeeded in combining resonant soft x-ray scattering (RSoXS) at ALS Beamline 11.0.1 with transmission electron microscopy tomography (TEMT) and other techniques to unambiguously determine morphologies comprising two nested hexagonally packed arrays of nanoscopic, cylindrical microdomains in the bulk and a core-shell nanostructure in a thin film. Not only has this work revealed a new phase of ABC tri-block copolymer with complicated morphology, it has illustrated the importance of RSoXS as a unique, powerful tool for examining complex, multi-component systems that could not be characterized with conventional methods.

89

Resonant Soft X-Ray Scattering of Tri-Block Copolymers  

NLE Websites -- All DOE Office Websites (Extended Search)

Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print In principle, tri-block copolymers (tri-BCPs), consisting of three chemically distinct polymers covalently joined together at the ends of each polymer chain, can serve as scaffolds and templates for fabricating a vast number of nanostructures. While quantitatively understanding the details of the morphology and the manner in which the different blocks interact with surfaces and interfaces is critical to success, previous experiments have been few. Now, an international team from the United States, Korea, and Japan has succeeded in combining resonant soft x-ray scattering (RSoXS) at ALS Beamline 11.0.1 with transmission electron microscopy tomography (TEMT) and other techniques to unambiguously determine morphologies comprising two nested hexagonally packed arrays of nanoscopic, cylindrical microdomains in the bulk and a core-shell nanostructure in a thin film. Not only has this work revealed a new phase of ABC tri-block copolymer with complicated morphology, it has illustrated the importance of RSoXS as a unique, powerful tool for examining complex, multi-component systems that could not be characterized with conventional methods.

90

Resonant Soft X-Ray Scattering of Tri-Block Copolymers  

NLE Websites -- All DOE Office Websites (Extended Search)

Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print In principle, tri-block copolymers (tri-BCPs), consisting of three chemically distinct polymers covalently joined together at the ends of each polymer chain, can serve as scaffolds and templates for fabricating a vast number of nanostructures. While quantitatively understanding the details of the morphology and the manner in which the different blocks interact with surfaces and interfaces is critical to success, previous experiments have been few. Now, an international team from the United States, Korea, and Japan has succeeded in combining resonant soft x-ray scattering (RSoXS) at ALS Beamline 11.0.1 with transmission electron microscopy tomography (TEMT) and other techniques to unambiguously determine morphologies comprising two nested hexagonally packed arrays of nanoscopic, cylindrical microdomains in the bulk and a core-shell nanostructure in a thin film. Not only has this work revealed a new phase of ABC tri-block copolymer with complicated morphology, it has illustrated the importance of RSoXS as a unique, powerful tool for examining complex, multi-component systems that could not be characterized with conventional methods.

91

Resonant Soft X-Ray Scattering of Tri-Block Copolymers  

NLE Websites -- All DOE Office Websites (Extended Search)

Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print Resonant Soft X-Ray Scattering of Tri-Block Copolymers Print In principle, tri-block copolymers (tri-BCPs), consisting of three chemically distinct polymers covalently joined together at the ends of each polymer chain, can serve as scaffolds and templates for fabricating a vast number of nanostructures. While quantitatively understanding the details of the morphology and the manner in which the different blocks interact with surfaces and interfaces is critical to success, previous experiments have been few. Now, an international team from the United States, Korea, and Japan has succeeded in combining resonant soft x-ray scattering (RSoXS) at ALS Beamline 11.0.1 with transmission electron microscopy tomography (TEMT) and other techniques to unambiguously determine morphologies comprising two nested hexagonally packed arrays of nanoscopic, cylindrical microdomains in the bulk and a core-shell nanostructure in a thin film. Not only has this work revealed a new phase of ABC tri-block copolymer with complicated morphology, it has illustrated the importance of RSoXS as a unique, powerful tool for examining complex, multi-component systems that could not be characterized with conventional methods.

92

Physica B 283 (2000) 75}78 Phase-sensitive surface X-ray scattering study of a crystalline  

E-Print Network (OSTI)

Physica B 283 (2000) 75}78 Phase-sensitive surface X-ray scattering study of a crystalline organic}organic An X-ray study of a crystalline organic}organic heterostructure, consisting of a "lm of PTCDA (3 the determination of d with great sensitivity. 2000 Elsevier Science B.V. All rights reserved. PACS: 61.66.Hq; 68

Schreiber, Frank

93

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

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.

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)

2012-10-15T23:59:59.000Z

94

K-(alpha) X-ray Thomson Scattering From Dense Plasmas  

SciTech Connect

Spectrally resolved Thomson scattering using ultra-fast K-{alpha} x-rays has measured the compression and heating of shocked compressed matter. The evolution and coalescence of two shock waves traveling through a solid density LiH target were characterized by the elastic scattering component. The density and temperature at shock coalescence, 2.2 eV and 1.7 x 10{sup 23}cm{sup -3}, were determined from the plasmon frequency shift and the relative intensity of the elastic and inelastic scattering features in the collective scattering regime. The observation of plasmon scattering at coalescence indicates a transition to the dense metallic state in LiH. The density and temperature regimes accessed in these experiments are relevant for inertial confinement fusion experiments and for the study of planetary formation.

Kritcher, A L; Neumayer, P; Castor, J; Doppner, T; Falcone, R W; Landen, O L; Lee, H J; Lee, R W; Morse, E C; Ng, A; Pollaine, S; Price, D; Glenzer, S H

2009-05-07T23:59:59.000Z

95

Synchrotron X-ray Scattering Analysis of the Interaction Between Corn Starch and an Exogenous Lipid During Hydrothermal Treatment  

Science Conference Proceedings (OSTI)

Lipids have an important effect on starch physicochemical properties. There exist few reports about the effect of exogenous lipids on native corn starch structural properties. In this work, a study of the morphological, structural and thermal properties of native corn starch with L-alpha-lysophosphatidylcholine (LPC, the main phospholipid in corn) was performed under an excess of water. Synchrotron radiation, in the form of real-time small and wide-angle X-ray scattering (SAXS/WAXS), was used in order to track structural changes in corn starch, in the presence of LPC during a heating process from 30 to 85 C. When adding LCP, water absorption decreased within starch granule amorphous regions during gelatinization. This is explained by crystallization of the amylose-LPC inclusion complex during gelatinization, which promotes starch granule thermal stability at up to 95 C. Finally, a conceptual model is proposed for explaining the formation mechanism of the starch-LPC complex.

E Hernandez-Hernandez; C Avila-Orta; B Hsiao; j Castro-Rosas; J Gallegos-Infante; J Morales-Castro; L Ochoa-Martinez; C Gomez-Aldapa

2011-12-31T23:59:59.000Z

96

Epp: A C++ EGSnrc user code for x-ray imaging and scattering simulations  

Science Conference Proceedings (OSTI)

Purpose: Easy particle propagation (Epp) is a user code for the EGSnrc code package based on the C++ class library egspp. A main feature of egspp (and Epp) is the ability to use analytical objects to construct simulation geometries. The authors developed Epp to facilitate the simulation of x-ray imaging geometries, especially in the case of scatter studies. While direct use of egspp requires knowledge of C++, Epp requires no programming experience. Methods: Epp's features include calculation of dose deposited in a voxelized phantom and photon propagation to a user-defined imaging plane. Projection images of primary, single Rayleigh scattered, single Compton scattered, and multiple scattered photons may be generated. Epp input files can be nested, allowing for the construction of complex simulation geometries from more basic components. To demonstrate the imaging features of Epp, the authors simulate 38 keV x rays from a point source propagating through a water cylinder 12 cm in diameter, using both analytical and voxelized representations of the cylinder. The simulation generates projection images of primary and scattered photons at a user-defined imaging plane. The authors also simulate dose scoring in the voxelized version of the phantom in both Epp and DOSXYZnrc and examine the accuracy of Epp using the Kawrakow-Fippel test. Results: The results of the imaging simulations with Epp using voxelized and analytical descriptions of the water cylinder agree within 1%. The results of the Kawrakow-Fippel test suggest good agreement between Epp and DOSXYZnrc. Conclusions: Epp provides the user with useful features, including the ability to build complex geometries from simpler ones and the ability to generate images of scattered and primary photons. There is no inherent computational time saving arising from Epp, except for those arising from egspp's ability to use analytical representations of simulation geometries. Epp agrees with DOSXYZnrc in dose calculation, since they are both based on the well-validated standard EGSnrc radiation transport physics model.

Lippuner, Jonas; Elbakri, Idris A.; Cui Congwu; Ingleby, Harry R. [Department of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada) and Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Department of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada) and Department of Radiology, University of Manitoba, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9 (Canada); Department of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada)

2011-03-15T23:59:59.000Z

97

Resonant Soft X-ray Scattering Studies of Multiferroic YMn2O5  

SciTech Connect

We performed soft x-ray resonant scattering at the MnL{sub 2,3}- and OK edges of YMn{sub 2}O{sub 5}. While the resonant intensity at the MnL{sub 2,3} edges represent the magnetic order parameter, the resonant scattering at the OK edge is found to be directly related to the macroscopic ferroelectric polarization. The latter observation reveals the important role of the spin-dependent Mn-O hybridization for the multiferroicity of YMn{sub 2}O{sub 5}. We present details about how to obtain correct energy dependent lineshapes and discuss the origin of the resonant intensity at the OK edge.

Partzsch, S.; Wilkins, S.B.; Schierle, E.; Soltwisch, V.; Hill, J.P.; Weschke, E.; Souptel, D.; Buchner, B.; Geck, J.

2011-06-17T23:59:59.000Z

98

Hydrogen bonding and coordination in normal and supercritical water from X-ray inelastic scattering  

E-Print Network (OSTI)

A direct measure of hydrogen bonding in water under conditions ranging from the normal state to the supercritical regime is derived from the Compton scattering of inelastically-scattered X-rays. First, we show that a measure of the number of electrons $n_e$ involved in hydrogen bonding at varying thermodynamic conditions can be directly obtained from Compton profile differences. Then, we use first-principles simulations to provide a connection between $n_e$ and the number of hydrogen bonds $n_{HB}$. Our study shows that over the broad range studied the relationship between $n_e$ and $n_{HB}$ is linear, allowing for a direct experimental measure of bonding and coordination in water. In particular, the transition to supercritical state is characterized by a sharp increase in the number of water monomers, but also displays a significant number of residual dimers and trimers.

Patrick H. -L. Sit; Christophe Bellin; Bernardo Barbiellini; D. Testemale; J. -L. Hazemann; T. Buslaps; Nicola Marzari; Abhay Shukla

2007-02-26T23:59:59.000Z

99

Defects and Polytypism in SiC: The Role of Diffuse X-Ray Scattering  

Science Conference Proceedings (OSTI)

Stacking faults (SFs) and the 3C-6H polytypic transition in thick (001)-oriented 3C-SiC crystals are studied by means of diffuse X-ray scattering. The presence of SFs lying in the {l_brace}111{r_brace} planes gives rise to streaked reciprocal lattice points with the streaks being parallel to the directions. In the case of low SF densities the defects are uncorrelated and the simulation of the diffuse intensity distribution allows to derive the SF density. In partially transformed crystals, the SFs are spatially correlated which gives rise to an intense and asymmetric diffuse scattering distribution. Its simulation allows to determine both the transformation mechanism and the transformation level.

Boulle, A.; Dompoint, D. [Science des Procedes Ceramiques et de Traitements de surface (SPCTS-CNRS UMR 6638), ENSCI 47 avenue Albert Thomas 87065 Limoges Cedex (France); Galben-Sandulache, I.; Chaussende, D. [Laboratoires des Materiaux et du Genie Physique (LMGP-CNRS UMR 5628), Grenoble INP, Minatec 3 parvis Louis Neel, BP 257, 38016 Grenoble Cedex 01 (France)

2010-11-01T23:59:59.000Z

100

Synchrotron X-ray scattering techniques for microelectronics-related materials studies  

Science Conference Proceedings (OSTI)

X-ray diffraction techniques using synchrotron radiation play a vital role in the understanding of structural behavior for a wide range of materials important in microelectronics. The extremely high flux of X-rays produced by synchrotron storage rings ...

J. L. Jordan-Sweet

2000-07-01T23:59:59.000Z

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101

The phonon density of states of {alpha}- {delta}-plutonium by inelastic x-ray scattering.  

Science Conference Proceedings (OSTI)

Inelastic x-ray scattering measurements of the phonon density of states (DOS) were performed on polycrystalline samples of pure {alpha}-Pu and {delta}-Pu{sub 0.98}Ga{sub 0.02} at room temperature. The heat capacity of {alpha}-Pu is well reproduced by contributions calculated from the measured phonon DOS plus conventional thermal-expansion and electronic contributions, showing that {alpha}-Pu is a 'well-behaved' metal in this regard. A comparison of the phonon DOS of the two phases at room temperature showed that the vibrational entropy difference between them is only a quarter of the total entropy difference expected from known thermodynamic measurements. The missing entropy is too large to be accounted for by conventional electronic entropy and evidence from the literature rules out a contribution from spin fluctuations. Possible alternative sources for the missing entropy are discussed.

Manley, M. E.; Said, A.; Fluss, M. J.; Wall, M.; Lashley, J. C.; Alatas, A.; Moore, K. T.; LLNL; LANL

2009-02-01T23:59:59.000Z

102

Changes in the Atomic Structure through Glass Transition Observed by X-Ray Scattering  

SciTech Connect

The glass transition involves a minor change in the internal energy, and yet the physical and mechanical properties of a glass change dramatically. In order to determine the evolution of the atomic structure through the glass transition, we employed in-situ synchrotron X-ray scattering measurements as a function of temperature on a model material: Zr-Cu-Al metallic glass. We found that the thermal expansion at the atomic level is smaller than the macroscopic thermal expansion, and significantly increases above the glass transition temperature. The observed changes in the pair-distribution function (PDF) are explained in terms of the fluctuations in the local atomic volume and their change through the glass transition.

Egami, Takeshi [ORNL

2012-01-01T23:59:59.000Z

103

Observation of Laser Induced Magnetization Dynamics in Co/Pd Multilayers with Coherent X-ray Scattering  

SciTech Connect

We report on time-resolved coherent x-ray scattering experiments of laser induced magnetization dynamics in Co/Pd multilayers with a high repetition rate optical pump x-ray probe setup. Starting from a multi-domain ground state, the magnetization is uniformly reduced after excitation by an intense 50 fs laser pulse. Using the normalized time correlation, we study the magnetization recovery on a picosecond timescale. The dynamic scattering intensity is separated into an elastic portion at length scales above 65 nm which retains memory of the initial domain magnetization, and a fluctuating portion at smaller length scales corresponding to domain boundary motion during recovery.

Wu, Benny

2012-04-05T23:59:59.000Z

104

Single-shot Time-resolved X-ray Scattering Measurements in ...  

Science Conference Proceedings (OSTI)

We will describe detailed new measurement system and their results. ... Induced and Observed by Interaction with an Intense Femtosecond X-ray Laser Pulse.

105

A setup for resonant inelastic soft x-ray scattering on liquids at free electron laser light sources  

SciTech Connect

We present a flexible and compact experimental setup that combines an in vacuum liquid jet with an x-ray emission spectrometer to enable static and femtosecond time-resolved resonant inelastic soft x-ray scattering (RIXS) measurements from liquids at free electron laser (FEL) light sources. We demonstrate the feasibility of this type of experiments with the measurements performed at the Linac Coherent Light Source FEL facility. At the FEL we observed changes in the RIXS spectra at high peak fluences which currently sets a limit to maximum attainable count rate at FELs. The setup presented here opens up new possibilities to study the structure and dynamics in liquids.

Kunnus, Kristjan; Schreck, Simon; Foehlisch, Alexander [Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Institut fuer Physik und Astronomie, Universitaet Potsdam, Karl-Liebknecht-Strasse 24/25, 14476 Potsdam (Germany); Rajkovic, Ivan; Quevedo, Wilson; Gruebel, Sebastian; Scholz, Mirko [IFG Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37070 Goettingen (Germany); Eckert, Sebastian; Beye, Martin; Suljoti, Edlira; Weniger, Christian; Wernet, Philippe [Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Kalus, Christian [Abteilung Betrieb Beschleuniger BESSYII, Helmholtz-Zentrum Berlin GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Nordlund, Dennis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Zhang, Wenkai; Hartsock, Robert W.; Gaffney, Kelly J. [PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Schlotter, William F.; Turner, Joshua J. [Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Kennedy, Brian [MAX-lab, PO Box 118, 221 00 Lund (Sweden); and others

2012-12-15T23:59:59.000Z

106

Resonant Inelastic X-ray Scattering of Rare-Earth and CopperSystems  

Science Conference Proceedings (OSTI)

Rare earths and copper systems were studied using X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS). The use of monochromased synchotron radiation and improved energy resolution for RIXS made possible to obtain valuable information on the electronic structure in 4f, 5f and 3d systems. Experimental results for rare-earths (Ho, Gd, Cm, U, Np, Pu) were analyzed by atomic multiplet theory based on the Hartree-Fock calculations. The inelastic scattering structures in RIXS spectra at 5d edge of actinides found to be sensitive to actinide oxidation states in different systems. Comparison of experimental and calculated Cm 5d RIXS spectra gave direct information about valency of the 248-curium isotope in oxide. Scientific understanding of processes that control chemical changes of radioactive species from spent fuel is improved by studying interactions of actinide ions (U, Np, Pu) with corroded iron surfaces. RIXS measurements at the actinide 5d edge found to be sensitive to actinide oxidation states in different systems. Comparison of experimental and calculated Cm 5d RIXS spectra gave direct information about valency of the 248 curium isotope in oxide. Scientific understanding of processes that control chemical changes of radioactive species from spent fuel is improved by studying interactions of actinide ions (U, Np, Pu) with corroded iron surfaces. RIXS measurements at the actinide 5d edge indicate the reduction of U(VI), NP(V) and Pu(VI) to U(IV), Np(IV) and Pu(IV) by presence of iron ions. This thesis is also addressed to the study of changes in the electronic structure of copper films during interaction with synthetic groundwater solutions. The surface modifications induced by chemical reactions of oxidized 100 Angstrom Cu films with CL{sup -}, SO{sub 4}{sup 2-} and HCO{sub 3}{sup -} ions in aqueous solutions with various concentrations were studied in-situ using XAS. It was shown that the pH value, the concentration of Cl{sup -} ion and presence of HC{sub 3}{sup -} ion in the solutions strongly affect the speed of the corrosion reaction. The Cu 2p RIXS was used to distinguish between the species present on the copper surface while in contact with groundwater solution.

Kvashnina, Kristina

2007-07-11T23:59:59.000Z

107

A new method to derive electronegativity from resonant inelastic x-ray scattering  

SciTech Connect

Electronegativity is a well-known property of atoms and substituent groups. Because there is no direct way to measure it, establishing a useful scale for electronegativity often entails correlating it to another chemical parameter; a wide variety of methods have been proposed over the past 80 years to do just that. This work reports a new approach that connects electronegativity to a spectroscopic parameter derived from resonant inelastic x-ray scattering. The new method is demonstrated using a series of chlorine-containing compounds, focusing on the Cl 2p{sup -1}LUMO{sup 1} electronic states reached after Cl 1s{yields} LUMO core excitation and subsequent KL radiative decay. Based on an electron-density analysis of the LUMOs, the relative weights of the Cl 2p{sub z} atomic orbital contributing to the Cl 2p{sub 3/2} molecular spin-orbit components are shown to yield a linear electronegativity scale consistent with previous approaches.

Carniato, S.; Journel, L.; Guillemin, R.; Piancastelli, M. N.; Simon, M. [UPMC Univ Paris 06, UMR7614, Laboratoire de Chimie Physique-Matiere et Rayonnement, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); CNRS, LCPMR (UMR 7614), 11 rue Pierre et Marie Curie, 75231 Parix Cedex 05 (France); Stolte, W. C. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4009 (United States); Harry Reid Center for Environmental Studies, University of Nevada, Las Vegas, Nevada, 89154-4003 (United States); Lindle, D. W. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4009 (United States)

2012-10-14T23:59:59.000Z

108

Growth dynamics of pentacene thin films: Real-time synchrotron x-ray scattering study  

Science Conference Proceedings (OSTI)

Real-time synchrotron x-ray scattering in the anti-Bragg configuration was used to monitor the dynamics of pentacene film growth on inert substrates. A distributed-growth model, according to which pentacene molecules adsorbed on the nth layer can either nucleate and contribute to the growth of the (n+1)th layer or transfer downward and contribute to the growth of the nth layer, gave a good description of the data. For molecules adsorbed on the first and second layers, the probability of downward transfer was found to be dependent on the substrate, and independent of temperature within the range from 25 to 60 deg. C. For films grown on SiO{sub 2}, an Ehrlich-Schwoebel barrier of the order of 70 meV dominated downward transfer of pentacene molecules in layers away from the substrate. For films grown on an alkylated self-assembled monolayer, significant desorption of pentacene molecules from the substrate at elevated temperatures forced the growth mode toward the three-dimensional limit.

Mayer, Alex C.; Ruiz, Ricardo; Malliaras, George G. [Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Zhou, Hua; Headrick, Randall L. [Department of Physics, University of Vermont, Burlington, Vermont 05405 (United States); Kazimirov, Alexander [Cornell High Energy Synchrotron Source, Ithaca, New York 14853 (United States)

2006-05-15T23:59:59.000Z

109

Commissioning of a Soft X-ray Beamline PF-BL-16A with a Variable-Included-Angle Varied-Line-Spacing Grating Monochromator  

Science Conference Proceedings (OSTI)

The design and commissioning of a new soft X-ray beamline, BL-16A, at the Photon Factory is presented. The beamline consists of a pre-focusing mirror, an entrance slit, a variable-included-angle varied-line-spacing plane grating monochromator, and a post-focusing system as usual, and provides circularly and linearly polarized soft X rays in the energy range 200-1500 eV with an APPLE-II type undulator. The commissioning procedure for the beamline optics is described in detail, especially the check of the focal position for the zero-th order and diffracted X rays.

Amemiya, Kenta; Toyoshima, Akio; Kikuchi, Takashi; Kosuge, Takashi; Nigorikawa, Kazuyuki; Sumii, Ryohei; Ito, Kenji [Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

2010-06-23T23:59:59.000Z

110

X-ray resonant magnetic scattering study of magnetic stripe domains in a-GdFe thin films  

SciTech Connect

X-ray resonant magnetic scattering (XRMS) has been used to investigate the structure of magnetic stripe domain patterns in thin amorphous GdFe films. Under the influence of a perpendicular magnetic field, the scattered intensity displays a smooth transition from a structure factor of correlated stripes to the form factor of isolated domains. We derive a quite general expression that relates the total scattered intensity of XRMS to the absolute value of the magnetization. Furthermore, we compare our results for the domain period with domain theory. We obtain good agreement for prealigned stripes, but disorder tends to lead to an overestimation of the period measured with XRMS.

Miguel, J.; Peters, J. F.; Toulemonde, O. M.; Goedkoop, J. B. [Van der Waals-Zeeman Institute, University of Amsterdam, Valckenierstraat 65, 1018 XE, Amsterdam (Netherlands); Dhesi, S. S.; Brookes, N. B. [European Synchrotron Radiation Facility, ESRF, Boite Postale 220, F-38043 Grenoble Cedex (France)

2006-09-01T23:59:59.000Z

111

SSRL School 2008 on Hard X-ray Scattering Techniques in MES  

NLE Websites -- All DOE Office Websites (Extended Search)

May 20-22, 2008 SSRL School on Synchrotron X-ray Absorption Spectroscopy Techniques in Environmental and Materials Sciences: Theory and Application Group photo from the 2008 SSRL...

112

Soft x-ray scattering facility at the Advanced Light Source with real-time data processing and analysis  

Science Conference Proceedings (OSTI)

We present the development and characterization of a dedicated resonant soft x-ray scattering facility. Capable of operation over a wide energy range, the beamline and endstation are primarily used for scattering from soft matter systems around the carbon K-edge ({approx}285 eV). We describe the specialized design of the instrument and characteristics of the beamline. Operational characteristics of immediate interest to users such as polarization control, degree of higher harmonic spectral contamination, and detector noise are delineated. Of special interest is the development of a higher harmonic rejection system that improves the spectral purity of the x-ray beam. Special software and a user-friendly interface have been implemented to allow real-time data processing and preliminary data analysis simultaneous with data acquisition.

Gann, E.; Collins, B. A.; Ade, H. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202 (United States); Young, A. T.; Nasiatka, J.; Padmore, H. A.; Hexemer, A.; Wang, C. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Yan, H. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202 (United States); Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2012-04-15T23:59:59.000Z

113

In-situ Synchrotron Radiation X-ray Scattering Study On The Initial Structure Of Atomic Layer Deposition  

Science Conference Proceedings (OSTI)

Due to the excellent conformality of ALD, it is not only adopted thin film, but also has been adopted for the fabrication of nanostructures. The surface reaction of ALD process is dependent on the substrate condition, thus the study on initial stage of ALD process is crucial to achieve controllable film growth. By the way, because of quite low scattering intensity of initial ultra thin layer, the high flux Synchrotron Radiation is needed. Synchrotron radiation x-ray scattering measurements allow us to investigate the atomic structure evolution of a few nanometer thickness films at the initial growth stage, nondestructively. Ru and TaN ALD films were grown. The thickness, roughness, and electron density were estimated by X-Ray Reflectivity (XRR) analysis. The island structures and its coverage also were estimated.

Park, Y. J. [Pohang Accelerator Laboratory, POSTECH, Pohang, Gyeongbuk (Korea, Republic of); Department of MSE, POSTECH, Pohang, Gyeongbuk (Korea, Republic of); Lee, D. R. [Department of Physics, Soongsil univ., Seoul (Korea, Republic of); Baik, S. [Department of MSE, POSTECH, Pohang, Gyeongbuk (Korea, Republic of)

2011-12-23T23:59:59.000Z

114

X-Ray Interactions with Matter  

DOE Data Explorer (OSTI)

The primary interactions of low-energy x-rays within condensed matter, viz. photoabsorption and coherent scattering, are described for photon energies outside the absorption threshold regions by using atomic scattering factors. The atomic scattering factors may be accurately determined from the atomic photoabsorption cross sections using modified Kramers-Kronig dispersion relations. From a synthesis of the currently available experimental data and recent theoretical calculations for photoabsorption, the angle-independent, forward-scattering components of the atomic scattering factors have been thus semiempirically determined and tabulated here for 92 elements and for the region 50-30,000 eV. Atomic scattering factors for all angles of coherent scattering and at the higher photon energies are obtained from these tabulated forward-scattering values by adding a simple angle-dependent form-factor correction. The incoherent scattering contributions that become significant for the light elements at the higher photon energies are similarly determined. The basic x-ray interaction relations that are used in applied x-ray physics are presented here in terms of the atomic scattering factors. The bulk optical constants are also related to the atomic scattering factors. These atomic and optical relations are applied to the detailed calculation of the reflectivity characteristics of a series of practical x-ray mirror, multilayer, and crystal monochromators. Comparisons of the results of this semiempirical,"atom-like", description of x-ray interactions for the low-energy region with those of experiment and ab initio theory are presented. (Taken from the abstract in OSTI Record 6131765) (Specialized Interface)

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

115

Neutron and x-ray scattering studies of the metallurgical condition and residual stresses in Weldalite welds  

DOE Green Energy (OSTI)

Weldalite is a lithium-containing aluminum alloy which is being considered for aerospace applications because its favorable strength-to-weight ratio. Successful welding of this alloy depends on the control of the metallurgical condition and residual stresses in the heat affected zone. Neutron and x-ray scattering methods of residual stress measurement were applied to plasma arc welds made in aluminum-lithium alloy test panels as part of an evaluation of materials for use in welded structures. In the course of these studies discrepancies between x-ray and neutron results from the heat affected zone (HAZ) of the weld were found. Texture changes and recovery from the cold work, indicated in peak widths, were found in the HAZ as well. The consideration of x-ray and neutron results leads to the conclusion that there is a change in solute composition which modifies the d-spacings in the HAZ which affects the neutron diffraction determination of residual stresses. The composition changes give the appearance of significant compressive strains in the HAZ. This effect and sharp gradients in the texture give severe anomalies in the neutron measurement of residual stress. The use of combined x-ray and neutron techniques and the solution to the minimizing of the neutron diffraction anomalies are discussed.

Spooner, S. [Oak Ridge National Lab., TN (United States); Pardue, E.B.S. [Technology for Energy Corp., Knoxville, TN (United States)

1995-12-31T23:59:59.000Z

116

Polarization Dependence of L- and M-Edge Resonant Inelastic X-Ray Scattering in Transition-Metal Compounds  

SciTech Connect

The resonant inelastic x-ray scattering (RIXS) cross section at the L and M edges of transition-metal compounds is studied using an effective scattering operator. The intensities of the elastic peak and for spin-flip processes are derived. It is shown how the polarization dependence can be used to select transitions. Comparisons are made with experiment. A detailed analysis of the polarization and angular dependence of L- and M-edge RIXS for divalent copper compounds, such as the high-T{sub c} superconductors, is given.

van Veenendaal, Michel (ANL/NIU)

2010-12-03T23:59:59.000Z

117

Determining the electron-phonon coupling strength from Resonant Inelastic X-ray Scattering at transition metal L-edges  

SciTech Connect

We show that high-resolution Resonant Inelastic X-ray Scattering (RIXS) provides direct, element-specific and momentum-resolved information on the electron-phonon (e-p) coupling strength. Our theoretical analysis indicates how the e-p coupling can be extracted from RIXS spectra by determining the differential phonon scattering cross-section. An alternative manner to extract the coupling is to use the one- and two-phonon loss ratio, which is governed by the e-p coupling strength and the core-hole lifetime. This allows the determination of the e-p coupling on an absolute energy scale.

Ament, L.J.P.; van Veenendaal, M.; van den Brink, J. (Leiden); (NIU); (IFW Dresden)

2012-04-02T23:59:59.000Z

118

Exploring local atomic arrangements in amorphous and metastable phase change materials with x-ray and neutron total scattering  

SciTech Connect

Very little experimental work has conclusively explored the structural transformation between the amorphous and metastable crystalline phases of phase change chalcogenides. A recent flurry of theoretical work has supported likely mechanisms for the phase transition process in Ge-Sb-Te (GST) compositions and invigorated efforts at probing local atomic arrangements experimentally. The pair distribution function (PDF) formalism of total scattering data provides directly both local structure correlations at low real-space dimensions, and intermediate range order at higher length scales, a distinct advantage for following the relevant phase transition in phase change materials (PCM). A challenge facing the field is the difficulty in distinguishing separate peak contributions to pair correlation functions in amorphous and highly disordered samples. For example, various types of local order have been reported for Ge{sub x}Te{sub 1-x} phases, including both random mixtures and discrete structural units, and both 4-fold and 6-fold coordination around Ge. We describe our efforts in advancing capabilities for extracting and refining differential or partial pair distribution function data sets by combining neutron and x-ray total scattering, with extensions to isotopic substitution and anomalous x-ray scattering. Our results combining neutron and x-ray scattering for the Ge{sub x}Te{sub 1-x} series, for example, clearly distinguish Ge-Te and Te-Te contributions in nearest neighbor correlations. Presenting an additional challenge, phase change materials with fast switching speeds (those arguably of greatest technological interest) have stable bulk crystalline phases and do not readily form glasses until reduced to small dimensions. Thin film samples are inherently difficult to probe with conventional crystallographic methods. We demonstrate successful synchrotron x-ray total scattering experiments for PCM thin films with thicknesses between 100 nm and 1 um and describe how chemical short-range order and local bonding environments vary in amorphous, metastable and crystalline GeSb{sub 2}Te{sub 4} films. Total scattering methods for powders and thin films allow for a direct comparison of PCM properties (crystallization temperature, optical contrast between phases, phase change speed, etc.) with observed local structure and motivate further exploration into the atomic configurations enabling this fascinating class of materials.

Page, Katharine [Los Alamos National Laboratory; Daemen, Luc [Los Alamos National Laboratory; Proffen, Thomas [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

119

Inelastic x-ray scattering study of supercooled liquid and solid silicon.  

Science Conference Proceedings (OSTI)

Momentum-resolved inelastic x-ray scattering (IXS) technique is one of the powerful methods for the study of dynamical properties of a given system even in extreme conditions like high temperature and high pressure. At the same time, experimental studies of physical and structural properties of liquids have multiplied in recent years with the advent of containerless techniques. These methods reduce the possibility of contamination of specimens and remove external nucleation sites. Therefore, by combining the IXS method with the levitation method, the dynamical properties of stable liquids up to 3000 K and supercooled phase of liquids can be studied. Silicon is a basic material in the semiconductor industry and has been the subject of a large amount of experimental and theoretical studies over a long time. In the crystalline phase at ambient conditions, silicon is a diamond-structured semiconductor, but upon melting it undergoes a semiconductor-to-metal transition accompanied by significant changes in the structure and density. The coordination number increases from 4 in the solid to about 6.5 in the liquid, and liquid density is increased by about 10%. The principal purpose of the present study was to determine silicon's elastic modulus from the measurement of averaged sound speed determined from IXS. The experiments were carried out at the Advanced Photon Source (APS) beamline 3-ID with a high-resolution monochromator consisting of two nested channel-cut crystals and four backscattering analyzer setups in the horizontal scattering plane 6 m from the sample. The requirements for very high energy resolution and the basic principles of such instrumentation are discussed elsewhere as referenced. The levitation apparatus was enclosed in a bell jar specially designed for backscattering geometry with a separation of 10 cm between the sample and the detector. Silicon spheres of 2 to 3 mm in diameter were suspended in an argon gas jet and heated with a 270 W CO{sub 2} laser beam. Temperatures were measured during the experiment with a pyrometer whose operating wavelength was 0.65 {micro}m. The temperature gradient on the sample was estimated to be about +/- 20 K. The energy scans were taken for supercooled-liquid and hot-solid silicon at temperature T=1620 K. Sound velocities were determined from the initial slope of the excitation frequencies. Then, the longitudinal moduli for hotsolid and supercooled-liquid silicon were calculated from L = v{sub L}{sup 2}{rho} using measured velocities. In these calculations, density values were taken from Ohsaka et al. as referenced. Results are presented in Table 1. together with room-temperature, hot-solid single-crystal measurements, and stable-liquid values. Room-temperature longitudinal moduli were calculated from the values of the single-crystal elastic constants. They were measured between 300 K and 870 K. Since there was no phase transition up to temperature 1620 K for hot-solid silicon, it is reasonable to extrapolate these data to 1620 K in order to compare to our results for the hot solid. A significant difference (about 20%) is observed between our measurement and the extrapolated single-crystal value of the longitudinal modulus for solid silicon at temperature 1620K. This reduction of the longitudinal modulus may be an indication of the pre-melting. The factor of more than two change in the elastic modulus between supercooled liquid and hot solid at the same temperature can be attributed to the semiconductor-to-metal transition in silicon associated with melting. Also, the longitudinal modulus of the stable liquid is reported in Table 1. About a 10% difference is observed between the modulus of the supercooled and the stable liquid silicon. This can be interpreted as silicon still maintaining metallic properties with a significant increase in the degree of the directional bonding upon supercooling, as found in the x-ray diffraction and ab initio MD studies. All these results are discussed in reference.

Alatas, A.; Said, A.; Sinn, H.; Alp, E.E.; Kodituwakku, C.N.; Saboungi, M.L.; Price, D.L.; X-Ray Science Division; Western Michigan Univ.; Purdue Univ.; CRMD-CNRS; CRMHT-CNRS

2006-01-01T23:59:59.000Z

120

Tunable X-ray source  

DOE Patents (OSTI)

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

Boyce, James R. (Williamsburg, VA)

2011-02-08T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

X-ray diffraction and scattering studies of coal constituents. Final technical report, January 1-December 31, 1983  

DOE Green Energy (OSTI)

The general objective of this work has been to use x-ray diffraction and scattering to examine whole coals, coal macerals and minerals in order to perform the following studies: (1) to identify and explain differences in vitrinites and framboids from various coals; (2) to correlate differences with basic coal compositions and properties; and (3) to determine the systematic variability in the micro compositional variation of macerals. The accomplishments have been: (a) the development of the Fourier transform technique to do proximate and ultimate analyses in a quick fashion; and (b) the investigation of the structure of pyrite framboids and preliminary studies of coal macerals. 3 figures, 12 tables.

Pavlovic, A. S.; Renton, J. T.

1984-03-15T23:59:59.000Z

122

The Lx-Yx Relation: Using Galaxy Cluster X-Ray Luminosity as a Robust, Low Scatter Mass Proxy  

E-Print Network (OSTI)

We use a sample of 115 galaxy clusters at 0.1scatter in the relation is dominated by cluster cores, and a tight LY relation (11% intrinsic scatter in Lx) is recovered if sufficiently large core regions (0.15R500) are excluded. The intrinsic scatter is well described by a lognormal distribution and the relations are consistent for relaxed and disturbed/merging clusters. We investigate the LY relation in low-quality data (e.g. for clusters detected in X-ray survey data) by estimating Lx from soft band count rates, and find that the scatter increases somewhat to 21%. We confirm the tight correlation between Yx and mass and the self-similar evolution of that scaling relation out to z=0.6 for a subset of clusters in our sample with mass estimates from the literature. This is used to estimate masses for the entire sample and hence measure the LM relation. We find that the scatter in the LM relation is much lower than previous estimates, due to the full removal of cluster cores and more robust mass estimates. For high-redshift clusters the scatter in the LM relation remains low if cluster cores are not excluded. These results suggest that cluster masses can be reliably estimated from simple luminosity measurements in low quality data where direct mass estimates, or measurements of Yx are not possible. This has important applications in the estimation of cosmological parameters from X-ray cluster surveys.

B. J. Maughan

2007-03-19T23:59:59.000Z

123

Fe K-edge X-ray resonant magnetic scattering from Ba(Fe1?xCox)2As2 superconductors  

SciTech Connect

We present an X-ray resonant magnetic scattering study at the Fe-K absorption edge of the BaFe2As2 compound. The energy spectrum of the resonant scattering, together with our calculation using the full-potential linear-augmented plane wave method with a local density functional suggests that the observed resonant scattering arises from electric dipole (E1) transitions. We discuss the role of Fe K-edge X-ray resonant magnetic scattering in understanding the relationship between the structure and the antiferromagnetic transition in the doped Ba(Fe1?xCox)2As2 superconductors.

Kim, Min Gyu; Kreyssig, Andreas; Lee, Yongbin; McQueeney, Robert J.; Harmon, Bruce N.; Goldman, Alan I.

2012-06-15T23:59:59.000Z

124

SSRL School 2007 on Hard X-ray Scattering: Techniques in MES  

NLE Websites -- All DOE Office Websites (Extended Search)

In-situ scattering, S. Webb Amorphous materials, T. Hufnagel Tuesday Afternoon, SurfaceThin Film Techniques Epitaxial thin film scattering, A. Vailionis Polycrystalline thin...

125

Global molecular structure and interfaces : refining an RNA : RNA complex structure using solution x-ray scattering data.  

SciTech Connect

Determining the global architecture of multicomponent systems is a central problem in understanding biomacromolecular machines. Defining interfaces among components and the global structure of multicomponent systems is a central problem in understanding the biological interactions on a molecular level. We demonstrate that solution X-ray scattering data can be used to precisely determine intermolecular interfaces from just the subunit structures, in the complete absence of intermolecular NMR restraints using an example of a 30 kDa RNA-RNA complex. The backbone root-mean-square deviation (rmsd) between structures that are determined using the scattering data and using intermolecular distance restraints is about 0.4 {angstrom}. Further, we refined the global structure of the complex using scattering data as a global restraint. The rmsd in backbone structures that are determined with and without the scattering data refinement is about 3.2 {angstrom}, suggesting the impact of the refinement to the overall structure. Information about the 'global correctness' of solution RNA structures could not be practically obtained otherwise, due to the molecular nature of the RNA molecules, but could only be defined by the scattering data together by residual dipolar couplings. This method provides a powerful new approach for refining global structures of macromolecular complexes whose subunits are elongated.

Zuo, X.; Wang, J.; Foster, T. R.; Schwieters, C. D.; Tiede, D. M.; Butcher, S. E.; Wang, Y.-X.; Chemical Sciences and Engineering Division; NCI-Frederick; Univ. of Wisconin at Madison; NIH

2008-03-19T23:59:59.000Z

126

THE ROLE OF INVERSE COMPTON SCATTERING IN SOLAR CORONAL HARD X-RAY AND {gamma}-RAY SOURCES  

SciTech Connect

Coronal hard X-ray (HXR) and continuum {gamma}-ray sources associated with the impulsive phase of solar flares have been the subject of renewed interest in recent years. They have been interpreted in terms of thin-target, non-thermal bremsstrahlung emission. This interpretation has led to rather extreme physical requirements in some cases. For example, in one case, essentially all of the electrons in the source must be accelerated to non-thermal energies to account for the coronal HXR source. In other cases, the extremely hard photon spectra of the coronal continuum {gamma}-ray emission suggest that the low-energy cutoff of the electron energy distribution lies in the MeV energy range. Here, we consider the role of inverse Compton scattering (ICS) as an alternate emission mechanism in both the ultra- and mildly relativistic regimes. It is known that relativistic electrons are produced during powerful flares; these are capable of upscattering soft photospheric photons to HXR and {gamma}-ray energies. Previously overlooked is the fact that mildly relativistic electrons, generally produced in much greater numbers in flares of all sizes, can upscatter extreme-ultraviolet/soft X-ray photons to HXR energies. We also explore ICS on anisotropic electron distributions and show that the resulting emission can be significantly enhanced over an isotropic electron distribution for favorable viewing geometries. We briefly review results from bremsstrahlung emission and reconsider circumstances under which non-thermal bremsstrahlung or ICS would be favored. Finally, we consider a selection of coronal HXR and {gamma}-ray events and find that in some cases the ICS is a viable alternative emission mechanism.

Chen Bin [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Bastian, T. S. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)

2012-05-01T23:59:59.000Z

127

The Role of Inverse Compton Scattering in Solar Coronal Hard X-ray and Gamma-ray Sources  

E-Print Network (OSTI)

We consider the role of inverse Compton scattering (ICS) as a means of producing coronal hard X-ray (HXR) and continuum gamma-ray sources during solar flares. Coronal HXR and continuum gamma-ray emission observed during solar flares has been interpreted in terms of thin-target bremsstrahlung emission. In one case, this interpretation leads to the conclusion that the number of energetic electrons required to account for the coronal HXR source must be large, implying that essentially all electrons in the source must be accelerated to energies >~ 16 keV. In other cases, the spectral index of the photon spectrum of gamma-ray sources approaches the theoretical limit for bremsstrahlung emission (alpha ~ 1.5 - 2). Here we investigate ICS in both the fully relativistic and mildly relativistic regimes as an alternative to non-thermal bremsstrahlung. It is known that relativistic electrons are produced during powerful flares; these are capable of up-scattering soft photospheric photons to HXR energies. Previously overl...

Chen, Bin

2011-01-01T23:59:59.000Z

128

Microfluidic Platforms for on-chip Formulation and Small-Angle x-ray Analysis of the Phase Behavior of Lipid/Water Mixtures  

SciTech Connect

We present a microfluidic platform for on-chip formulation and X-ray analysis of lipidic mesophases formed upon mixing lipids and water. The platform is designed to study the effect of detergents on the phase behavior of lipid/water mixtures. The platform allows automated preparation of multiple samples of different composition from stock solutions and subsequent on-chip small-angle X-ray diffraction (SAXS) data collection. To ensure X-ray transparency of the platform we used thin layers of cyclic olefin copolymer (COC) and PDMS. The viability of the platform is demonstrated by mapping out a section of the phase diagram for lipid monoolein mixed with solutions of detergent {beta}-octylglucoside. The platform reported here is a viable alternative to the traditional method of establishing phase diagrams for lipid/solution mixtures. Compared to the conventional approach, a significantly smaller amount of sample is required for mapping phase diagrams of lipidic mesophases and samples of various compositions are prepared automatically. In ongoing work we are using these chips to rapidly determine the phase behavior of a range of lipids to establish their suitability for membrane protein crystallization, especially with respect to their sensitivity to detergent concentration.

Khvostichenko, Daria S.; Perry, Sarah L.; Kondrashkina, Elena; Guha, Sudipto; Brister, Keith; Kenis, Paul J.A. (UIUC); (NWU)

2012-03-27T23:59:59.000Z

129

An active-optic x-ray fluorescence analyzer with high energy resolution, large solid angle coverage, and a large tuning range  

SciTech Connect

A crystal-optic x-ray fluorescence energy analyzer has been designed and tested, which combines the features of electron-volt energy resolution, large solid angle coverage, and tunability over several kilo-electron-volts. The design is based upon the principle of active optics, with ten actuators available to optimally adjust the shape of a silicon crystal used in the Bragg geometry. In most applications the shape is that of a logarithmic spiral for high energy resolution with a spatially nonresolving detector, but a wide range of other shapes is also possible for applications such as imaging or single-shot spectroscopy in a spectral range of the operator's choosing.

Adams, Bernhard W.; Attenkofer, Klaus [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2008-02-15T23:59:59.000Z

130

Pressure and field tuning the magnetostructural phases of Mn3O4: Raman scattering and x-ray diffraction studies  

Science Conference Proceedings (OSTI)

We present temperature-, magnetic-field-, and pressure-dependent Raman scattering studies of single crystal Mn{sub 3}O{sub 4}, combined with temperature- and field-dependent x-ray diffraction studies, revealing the novel magnetostructural phases in Mn{sub 3}O{sub 4}. Our temperature-dependent studies showed that the commensurate magnetic transition at T{sub 2} = 33K in the binary spinel Mn{sub 3}O{sub 4} is associated with a structural transition from tetragonal to orthorhombic structures. Field-dependent studies showed that the onset and nature of this structural transition can be controlled with an applied magnetic field, and revealed evidence for a field-tuned quantum phase transition to a tetragonal spin-disordered phase for H {parallel} [1{bar 1}0]. Pressure-dependent Raman measurements showed that the magnetic easy axis direction in Mn{sub 3}O{sub 4} can be controlled - and the ferrimagnetic transition temperature increased - with applied pressure. Finally, combined pressure- and magnetic-field-tuned Raman measurements revealed a rich magnetostructural phase diagram - including a pressure- and field-induced magnetically frustrated tetragonal phase in the PH phase diagram - that can be generated in Mn{sub 3}O{sub 4} with applied pressure and magnetic field.

Kim, M.; Nelson, C.; Chen, X.M.; Wang, X.; Budakian, R.; Abbamonte, P. & Cooper, S.L.

2011-11-18T23:59:59.000Z

131

Dissolution dynamics of the calcite-water interface observed in situ by glancing-incidence X-ray scattering  

DOE Green Energy (OSTI)

Glancing-incidence X-ray scattering measurements made at the National Synchrotron Light Source were used to investigate dissolution dynamics in situ at the calcite-water interface. The relation between calcite saturation state and roughness of the calcite (1014) cleavage surface as a function of time was examined during pH titrations of an initially calcite-saturated solution. Systematic variations in roughness were observed as a function of saturation state as pH was titrated to values below that of calcite saturation. Different steady-state values of roughness were evident at fixed values of {Delta}G{sub r}, and these were correlated with the extent of undersaturation. A significant increase in roughness begins to occur with increasing undersaturation at a {Delta}G{sub r} value of approximately {minus}2.0 kcal/mol. The dissolution rate corresponding to this increase is about 1.5 x 10{sup 7} mmol/cm {center_dot} sec. This increase in roughness is attributed to a transition in the principal rate-determining dissolution mechanism, and is consistent with both powder-reaction studies of dissolution kinetics and single-crystal dissolution studies by atomic force microscopy. These data indicate some important potential applications of GIXS in the study of mineral-water interface geochemistry.

Sturchio, N.C.; Chiarello, R.P.

1995-06-02T23:59:59.000Z

132

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

SciTech Connect

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.

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

2011-04-01T23:59:59.000Z

133

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

Science Conference Proceedings (OSTI)

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

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

2010-12-07T23:59:59.000Z

134

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

Science Conference Proceedings (OSTI)

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

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

2010-09-14T23:59:59.000Z

135

Structural and magnetic properties of transition metal substituted BaFe{sub 2}As{sub 2} compounds studied by x-ray and neutron scattering  

Science Conference Proceedings (OSTI)

The purpose of my dissertation is to understand the structural and magnetic properties of the newly discovered FeAs-based superconductors and the interconnection between superconductivity, antiferromagnetism, and structure. X-ray and neutron scattering techniques are powerful tools to directly observe the structure and magnetism in this system. I used both xray and neutron scattering techniques on di#11;erent transition substituted BaFe2As2 compounds in order to investigate the substitution dependence of structural and magnetic transitions and try to understand the connections between them.

Kim, Min Gyu [Ames Laboratory

2012-08-28T23:59:59.000Z

136

Theoretical treatments of the bound-free contribution and experimental best practice in X-ray Thomson scattering from warm dense matter  

SciTech Connect

By comparison with high-resolution synchrotron x-ray experimental results, we assess several theoretical treatments for the bound-free (core-electron) contribution to x-ray Thomson scattering (i.e., also known as nonresonant inelastic x-ray scattering). We identify an often overlooked source of systematic error in the plane-wave form factor approximation (PWFFA) used in the inference of temperature, ionization state, and free electron density in some laser-driven compression studies of warm dense matter. This error is due to a direct violation of energy conservation in the PWFFA. We propose an improved practice for the bound-free term that will be particularly relevant for XRTS experiments performed with somewhat improved energy resolution at the National Ignition Facility or the Linac Coherent Light Source. Our results raise important questions about the accuracy of state variable determination in XRTS studies, given that the limited information content in low-resolution XRTS spectra does not strongly constrain the models of electronic structure being used to fit the spectra.

Mattern, Brian A.; Seidler, Gerald T. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States)

2013-02-15T23:59:59.000Z

137

A Survey of Students from the National School on Neutron and X-ray Scattering: Communication Habits and Preferences  

Science Conference Proceedings (OSTI)

Oak Ridge National Laboratory (ORNL) offers the scientific community unique access to two types of world-class neutron sources at a single site - the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR). The 85-MW HFIR provides one of the highest steady-state neutron fluxes of any research reactor in the world. And the SNS is one of the world's most intense pulse neutron beams. Management of these resources is the responsibility of the Neutron Sciences Directorate (NScD). NScD started conducting the National School on Neutron and X-ray Scattering (NXS) in conjunction with the Advanced Photon Source (APS) at Argonne National Laboratory in 2007. This survey was conducted to determine the most effective ways to reach students with information about what SNS and HFIR offer the scientific community, including content and communication vehicles. The emphasis is on gaining insights into compelling messages and the most effective channels, e.g., Web sites and social media, for communicating with students about neutron science The survey was conducted in two phases using a classic qualitative investigation to confirm language and content followed by a survey designed to quantify issues, assumptions, and working hypotheses. Phase I consisted of a focus group in late June 2010 with students attending NXS. The primary intent of the group was to inform development of an online survey. Phase two consisted of an online survey that was developed and pre-tested in July 2010 and launched on August 9, 2010 and remained in the field until September 9, 2010. The survey achieved an overall response rate of 48% for a total of 157 completions. The objective of this study is to determine the most effective ways to reach students with information about what SNS and HFIR offer the scientific community, including content and communication vehicles. The emphasis is on gaining insights into compelling messages and the most effective channels, e.g., Web sites, social media, for communicating with students about neutron science.

Bryant, Rebecca [Bryant Research, LLC

2010-12-01T23:59:59.000Z

138

In-line phase-contrast imaging of a biological specimen using a compact laser-Compton scattering-based x-ray source  

SciTech Connect

Laser-Compton scattering (LCS) x-ray sources have recently attracted much attention for their potential use at local medical facilities because they can produce ultrashort pulsed, high-brilliance, and quasimonochromatic hard x rays with a small source size. The feasibility of in-line phase-contrast imaging for a 'thick' biological specimens of rat lumbar vertebrae using the developed compact LCS-X in AIST was investigated for the promotion of clinical imaging. In the higher-quality images, anatomical details of the spinous processes of the vertebrae are more clearly observable than with conventional absorption radiography. The results demonstrate that phase-contrast radiography can be performed using LCS-X.

Ikeura-Sekiguchi, H.; Kuroda, R.; Yasumoto, M.; Toyokawa, H.; Koike, M.; Yamada, K. [National Institute of Advanced Industrial Science and Technology (AIST), Central 2-5, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Sakai, F. [Sumitomo Heavy Industries, Ltd. (SHI), 2-1-1, Yatocho, Nishitokyo, Tokyo 188-8585 (Japan); Mori, K.; Maruyama, K. [Ibaraki Prefectural University of Health Sciences, 4669-2, Ami, Inashiki, Ibaraki 300-0394 (Japan); Oka, H.; Kimata, T. [St. Marianna University School of Medicine, 2-16-1, Sugao, Miyamae-ku, Kawasaki City 216-8512 (Japan)

2008-03-31T23:59:59.000Z

139

Hydrogen absorption in epitaxial W/Nb(001) and polycrystalline Fe/Nb(110) multilayers studied in-situ by X-ray/neutron scattering techniques and X-ray absorption spectroscopy  

DOE Green Energy (OSTI)

Hydrogen can be absorbed in large quantities by 100 {angstrom} thin Nb layers embedded in epitaxial W/Nb and polycrystalline Fe/Nb multilayers. The solubility and the hydrogen-induced structural changes of the host lattice are explored in-situ by small-angle neutron/X-ray reflectometry and high-angle diffraction. These measurements reveal for both systems that the relative out-of-plane expansion of the Nb layers is considerably larger than the relative increase of the Nb interplanar spacing indicating two distinctly different mechanisms of hydrogen absorption. In Fe/Nb multilayers, hydrogen expands the Nb interplanar spacing in a continuous way as function of the external pressure. In contrast, the Nb lattice expansion is discontinuous in epitaxial W/Nb multilayers: A jump in the Nb(002) Bragg reflection position occurs at a critical hydrogen pressure of 1 mbar. In-situ EXAFS spectroscopy also exhibits an irreversible expansion of the Nb lattice in the film plane for p{sub H{sub 2}}> 1 mbar. This can be regarded as a structural phase transition from an exclusively out-of-plane to a three-dimensionally expanded state at low and high hydrogen pressures, respectively.

Klose, F.; Rehm, C.; Fieber-Erdmann, M.; Holub-Krappe, E.; Bleif, H. J.; Sowers, H.; Goyette, R.; Troger, L.; Maletta, H.

1999-11-02T23:59:59.000Z

140

Chandra Observations and Monte Carlo Simulations of the Grain-Scattered Halo of the Binary X-Ray Pulsar 4U 1538-52  

E-Print Network (OSTI)

Properties of the X-ray halo of the eclipsing X-ray pulsar 4U 1538-52 are derived from a 25 ksec observation by the Chandra X-Ray Observatory. Profiles of the halo, compiled in two energy ranges, 2 to 4 keV and 4 to 6 keV, and three time intervals before and after an eclipse immersion, exhibit a three-peak shape. The observed profiles are fitted by the profiles of a simulated halo generated by a Monte Carlo ray-tracing code operating on a model of three discrete clouds and a spectrum of the photons emitted by the source over a period of time extending from 270 ksec before the observation began till it ended. The distances of the two nearer dust clouds are fixed at the distances of the peaks of atomic hydrogen derived from the 21-cm spectrum in the direction of the X-ray source, namely at 1.30 and 2.56 kpc. A good fit is achieved with the source at a distance 4.5 kpc, the distance of the third cloud at 4.05 kpc, the total scattering optical depth of the three clouds equal to 0.159 at 3 keV, and the column density of hydrogen set to 4.6x10^22 cm^-2. With Av=6.5 mag for the binary companion star, QV Nor, the ratio of the scattering optical depth at 3 keV to the visual extinction is 0.0234 mag^-1.

George W. Clark

2004-04-16T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Oxygen-diffusion limited metal combustions in Zr, Ti, and Fe foils: Time- and angle-resolved x-ray diffraction studies  

Science Conference Proceedings (OSTI)

The transient phase and chemical transformations of diffusion controlled metal combustions in bulk Zr, Ti, and Fe foils have been investigated, in situ, using novel time- and angle-resolved x-ray diffraction (TARXD). The TARXD employs monochromatic synchrotron x-rays and a fast-rotating diffracted beam chopper resolving the diffraction image temporally in time-resolution of {approx}45 {mu}s along the azimuth on a 2D pixel array detector. The metal foil strips (10-25 {mu}m in thickness) are ignited using a pulsed electrical heating with a typical heating rate of {approx}10{sup 6} K/s. The x-ray results indicate that the combustion occurs in molten metals, producing a wide range of stoichiometric solid oxides. It reflects an enhanced oxygen solubility and mobility of molten metals with respect to those of solid metals. However, the initial oxides formed are mainly oxygen-deficient metal oxides of ZrO, TiO, and FeO/Fe{sub 3}O{sub 4} - the lowest suboxides stable at these high temperatures. These transition metal monoxides further react with unreacted molten metals, yielding the secondary products of Zr{sub 3}O, Ti{sub 3}O, and Ti{sub 2}O - but not in FeO/Fe{sub 3}O{sub 4}. On the other hand, the higher stoichiometric oxides of ZrO{sub 2} and TiO{sub 2} are formed in the later time only on the metal surface. These results clearly indicate that the combustion process of metal strips is diffusion limited and strongly depends on the solubility and diffusivity of oxygen into molten metals. The time-resolved diffraction data reveals no evidence for metal oxidation in solids, but a series of temperature-induced polymorphic phase transitions. The dynamic thermal expansibility of Fe measured in the present fast heating experiments is similar to those in static conditions (3.3*10{sup -5}/K vs 3.5*10{sup -5}/K for {alpha}-Fe and 6.5*10{sup -5}/K versus 7.0*10{sup -5}/K for {gamma}-Fe).

Wei, Haoyan; Yoo, Choong-Shik; Chen, Jing-Yin; Shen, Guoyin (CIW); (WSU)

2012-04-30T23:59:59.000Z

142

The Extended Q-Range Small Angle Neutron Scattering ...  

Science Conference Proceedings (OSTI)

Abstract Scope, The Extended Q-Range Small Angle Neutron Scattering Diffractometer (EQ-SANS) at the Spallation Neutron Source (SNS) is a high intensity ...

143

Industrial Applications at Small Angle Neutron Scattering and ...  

Science Conference Proceedings (OSTI)

... at Small Angle Neutron Scattering and Neutron Diffraction of HANARO Reactor .... Structure/Microstructure Analysis of Faulted and Modular Materials from ...

144

USANS: the Ultra-Small-Angle Neutron Scattering Instrument at...  

NLE Websites -- All DOE Office Websites (Extended Search)

USANS-Ultra-Small-Angle Neutron Scattering Instrument USANS is designed for the study of hierarchical structures in natural and artificial materials. It can be considered an...

145

X-ray data booklet. Revision  

SciTech Connect

A compilation of data is presented. Included are properties of the elements, electron binding energies, characteristic x-ray energies, fluorescence yields for K and L shells, Auger energies, energy levels for hydrogen-, helium-, and neonlike ions, scattering factors and mass absorption coefficients, and transmission bands of selected filters. Also included are selected reprints on scattering processes, x-ray sources, optics, x-ray detectors, and synchrotron radiation facilities. (WRF)

Vaughan, D. (ed.)

1986-04-01T23:59:59.000Z

146

Soft x-ray circular dichroism and scattering using a modulated elliptically polarizing wiggler and double synchronous detection  

Science Conference Proceedings (OSTI)

We have constructed an experimental station (beamline) at the National Synchrotron Light Source to measure circular dichroism (CD) using soft x-rays (250 {le} hv {le} 900 eV) from a time modulated elliptically polarizing wiggler. The polarization of the soft x-ray beam switches periodically between two opposite polarizations, hence permitting the use of phase-sensitive (lock-in) detection. While the wiggler can be modulated at frequencies up to 100 Hz, switching transients limit the actual practical frequency to {approx}25 Hz. With analog detection, switching transients are blocked by a chopper synchronized to the frequency and phase of the wiggler. The CD is obtained from the ratio of the signal recovered at the frequency of polarization modulation, f, to the average beam intensity, which is recovered by synchronous detection at frequency 2f.

Sutherland, J.C.; Polewski, K.; Monteleone, D.C. [and others

1998-01-23T23:59:59.000Z

147

Study of the Stability of 3C-SiC Single Crystals Using High-Resolution Diffuse X-Ray Scattering  

SciTech Connect

The stability of (001)-oriented 3C silicon carbide crystals is studied by a method coupling high resolution x-ray diffraction and numerical simulations. The analysis of the diffuse scattering intensity distribution along selected directions in reciprocal space allows us to obtain qualitative and quantitative informations regarding the 3C-6H transition. Our latest results concerning the influence of the initial crystal quality (presence of defects) and of annealing time on the 3C-6H transition are presented in this article.

Dompoint, D.; Boulle, A. [Science des Procedes Ceramiques et de Traitements de Surface (SPCTS) CNRS UMR 6638, ENSCI, 47 avenue Albert Thomas 87065 Limoges Cedex (France); Galben-Sandulache, I. G.; Chaussende, D. [Laboratoire des Materiaux et du Genie Physique (LMGP) CNRS UMR 5628, Grenoble INP, Minatec, 3 parvis Louis Neel, BP 257, 38016 Grenoble Cedex 01 (France)

2010-11-01T23:59:59.000Z

148

X-ray Imaging Workshop  

NLE Websites -- All DOE Office Websites (Extended Search)

Imaging and Spectro-microscopy: Imaging and Spectro-microscopy: the Present and the Future Stanford Synchrotron Radiation Laboratory October 8-9, 2002 Organizers: John Miao & Keith Hodgson A workshop on "X-ray Imaging and Spectro-microscopy: the Present and the Future" was held on October 8-9, 2002. This workshop, organized by John Miao (SSRL) and Keith Hodgson (SSRL) provided a forum to discuss the scientific applications of a variety of imaging and spectro-microscopic techniques, including photoemission electron microscopy (PEEM), angle resolved photoemission spectroscopy (ARPES), coherent diffraction imaging, x-ray microscopy, micro-tomography, holographic imaging, and x-ray micro-probe. Twelve invited speakers discussed the important scientific applications of these techniques, and also predicted the future scientific directions with the advance of instrumentation and x-ray sources. The workshop was well attended with over fifty registered attendees.

149

A multi-crystal wavelength dispersive x-ray spectrometer  

Science Conference Proceedings (OSTI)

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.

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)

2012-07-15T23:59:59.000Z

150

An iterative three-dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam  

Science Conference Proceedings (OSTI)

X-ray film-screen mammography is currently the gold standard for detecting breast cancer. However, one disadvantage is that it projects a three-dimensional (3D) object onto a two-dimensional (2D) image, reducing contrast between small lesions and layers of normal tissue. Another limitation is its reduced sensitivity in women with mammographically dense breasts. Computed tomography (CT) produces a 3D image yet has had a limited role in mammography due to its relatively high dose, low resolution, and low contrast. As a first step towards implementing quantitative 3D mammography, which may improve the ability to detect and specify breast tumors, we have developed an analytical technique that can use Compton scatter to obtain 3D information of an object from a single projection. Imaging material with a pencil beam of polychromatic x rays produces a characteristic scattered photon spectrum at each point on the detector plane. A comparable distribution may be calculated using a known incident x-ray energy spectrum, beam shape, and an initial estimate of the object's 3D mass attenuation and electron density. Our iterative minimization algorithm changes the initially arbitrary electron density voxel matrix to reduce regular differences between the analytically predicted and experimentally measured spectra at each point on the detector plane. The simulated electron density converges to that of the object as the differences are minimized. The reconstruction algorithm has been validated using simulated data produced by the EGSnrc Monte Carlo code system. We applied the imaging algorithm to a cylindrically symmetric breast tissue phantom containing multiple inhomogeneities. A preliminary ROC analysis scores greater than 0.96, which indicate that under the described simplifying conditions, this approach shows promise in identifying and localizing inhomogeneities which simulate 0.5 mm calcifications with an image voxel resolution of 0.25 cm and at a dose comparable to mammography.

Van Uytven, Eric; Pistorius, Stephen; Gordon, Richard [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada) and Medical Physics, CancerCare Manitoba, 675 McDermot Ave., Winnipeg, Manitoba, R3A 1R9 (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Medical Physics, CancerCare Manitoba, 675 McDermot Ave., Winnipeg, Manitoba R3A 1R9 (Canada) and Department of Radiology, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9 (Canada); Department of Radiology, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9 (Canada) and Department of Electrical and Computer Engineering, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9 (Canada)

2007-01-15T23:59:59.000Z

151

Sure, a textbook can tell you about Bragg's Law and the x-ray absorption energies for any element in the periodic table, but it can't tell you how to plan and carry out an x-ray scattering experiment at one of the 50 or so synchrotron radiation facilitie  

NLE Websites -- All DOE Office Websites (Extended Search)

Report Report SSRL 6 th Annual School on Synchrotron X-ray Scattering Techniques in Materials and Environmental Sciences: Theory and Application SSRL SR-XRS participants. Synchrotron-based X-ray scattering (SR-XRS) techniques offer the ability to probe nano- and atomic-scale structure that dictates the properties of advanced technological and environmental materials. Important materials studied at the Stanford Synchrotron Radiation Lightsource (SSRL) include organic and inorganic thin films and interfaces, nanoparticles, complex oxides, solutions, polymers, minerals and poorly crystalline materials. Good planning and a good working knowledge of beam lines and techniques are required to successfully conduct SR-XRS measurements. This sixth annual School at SSRL on Synchrotron X-ray

152

Place-exchange mechanism of Pt (111) oxidation/reduction as observed by synchrotron X-ray scattering  

DOE Green Energy (OSTI)

Structural changes in the Pt(111) single crystal surface associated with incipient electrochemical oxidation/reduction were studied by {ital in}{ital situ} synchrotron x-ray reflectivity. It was shown that lifting of Pt atoms of the surface layer occurs, substantiating the long-standing hypothesis of a place-exchange mechanism for solution/metal interface oxidation. It was also shown that, for a charge transfer of {approx_lt}1.7 e{sup -}/Pt atom, the initially flat surface structure could be recovered by electrochemical reduction. In constrast, the surface was irreversibly roughened for amounts of charge transfer exceeding {approx}1.7 e{sup -}/Pt, but the roughening involved only the atoms in the top layer of the original flat surface. A detailed mechanism is proposed for the place-exchange mechanism and the subsequent roughening of the electrode surface.

You, H.; Nagy, Z.; Zurawski, D.J.; Chiarello, R.P.

1996-07-01T23:59:59.000Z

153

Changes in Delta-Plutonium Due to Aging as Observed by Continuous in-situ X-ray Scattering  

Science Conference Proceedings (OSTI)

The aging in plutonium is predominantly caused by its internal self irradiation. The self-irradiation in Pu-239 is by the decay process of transmuting the Pu atom into uranium atom and emitting an {alpha}-particle. Most of the lattice damage comes from the uranium recoil resulting in Frenkel type defects consisting of vacancies and self-interstitial atoms, helium in growth and defect clusters and possibly even though it is not yet observed, the generation of voids. As part of the stockpile stewardship, it is important to understand the changes in the structure and microstructures and their correlations to the physical properties. Changes in the physical properties has direct relationship to the quality of the structure, in terms of formation of defects and defect clustering, accumulation of voids, grain boundaries, phase changes and etc. which can adversely affects the stability of the material. These changes are very difficult to monitor because of the high activity of the sample, high atomic number making x-ray and synchrotron probe into the bulk very difficult (neutron probe is not feasible) and the long life time which normally requires decades to measure. In this paper we describe the development of an in-situ in-house transmission X-ray diffraction (XRD) experimental technique used to monitor the structural changes in these materials. This technique calls for a very thin sample of less that 2 {mu}m and to accelerate the aging process due to self-irradiation, spiked alloy of 7.5 weight percent of Pu-238 is used. This is equivalent to roughly 17 times the normal rate of aging. Current results suggest that over a period of 2.8 equivalent years, an increase of 0.5% in unit cell parameter is observed. The increase appears to be an abrupt jump at about 1.1 equivalent years, brought about by the collapsing of the atoms from the interstitials to the lattice sites. Further data analysis is on the way. (authors)

Saw, Cheng K.; Wall, Mark A.; Chung, Brandon W. [MSTD-CMS, Lawrence Livermore National Laboratory, Livermore, California (United States)

2007-07-01T23:59:59.000Z

154

On the absence of a positive sound dispersion in the THz dynamics of glycerol: an inelastic x-ray scattering study  

Science Conference Proceedings (OSTI)

The high frequency transport properties of glycerol are derived from inelastic x-ray scattering spectra measured at different pressures and compared with ultrasound absorption data. As a result, the presence of two distinct relaxation processes is inferred: a slow one, occurring in the GHz window and having an essentially structural character, and a fast one, related instead to microscopic degrees of freedom. While the former originates a neat increase of the apparent, i.e. frequency-dependent, sound velocity, the latter induces no visible dispersive effects on the acoustic propagation. The observed behavior is likely paradigmatic of all glass formers near or below the melting and it is here discussed and explained in some detail.

Cunsolo, Alessandro (BNL)

2012-10-23T23:59:59.000Z

155

Combined Use of Residual Dipolar Couplings and Solution X-ray Scattering To Rapidly Probe Rigid-Body Conformational Transitions in a Non-phosphorylatable Active-Site Mutant of the 128 kDa Enzyme I Dimer  

Science Conference Proceedings (OSTI)

The first component of the bacterial phosphotransferase system, enzyme I (EI), is a multidomain 128 kDa dimer that undergoes large rigid-body conformational transitions during the course of its catalytic cycle. Here we investigate the solution structure of a non-phosphorylatable active-site mutant in which the active-site histidine is substituted by glutamine. We show that perturbations in the relative orientations and positions of the domains and subdomains can be rapidly and reliably determined by conjoined rigid-body/torsion angle/Cartesian simulated annealing calculations driven by orientational restraints from residual dipolar couplings and shape and translation information afforded by small- and wide-angle X-ray scattering. Although histidine and glutamine are isosteric, the conformational space available to a Gln side chain is larger than that for the imidazole ring of His. An additional hydrogen bond between the side chain of Gln189 located on the EIN{sup {alpha}/{beta}} subdomain and an aspartate (Asp129) on the EIN{sup {alpha}} subdomain results in a small ({approx}9{sup o}) reorientation of the EIN{sup {alpha}} and EIN{sup {alpha}/{beta}} subdomains that is in turn propagated to a larger reorientation ({approx}26{sup o}) of the EIN domain relative to the EIC dimerization domain, illustrating the positional sensitivity of the EIN domain and its constituent subdomains to small structural perturbations.

Takayama, Yuki; Schwieters, Charles D.; Grishaev, Alexander; Ghirlando, Rodolfo; Clore, G. Marius (NIH)

2012-10-23T23:59:59.000Z

156

Direct detection of x-rays for protein crystallography  

DOE Patents (OSTI)

An apparatus and method for directly determining the crystalline structure of a protein crystal. The crystal is irradiated by a finely collimated x-ray beam. The interaction o f the x-ray beam with the crystal produces scattered x-rays. These scattered x-rays are detected by means of a large area, thick CCD which is capable of measuring a significant number of scattered x-rays which impact its surface. The CCD is capable of detecting the position of impact of the scattered x-ray on the surface of the CCD and the quantity of scattered x-rays which impact the same cell or pixel. This data is then processed in real-time and the processed data is outputted to produce an image of the structure of the crystal. If this crystal is a protein the molecular structure of the protein can be determined from the data received.

Atac, Muzaffer; McKay, Timothy

1997-12-01T23:59:59.000Z

157

X-Ray Topography  

Science Conference Proceedings (OSTI)

Sep 17, 2009 ... Stress Mapping Analysis by Ray Tracing (SMART): A New Technique ... technique of synchrotron X-ray topography, where a grid made out of ...

158

Obliquity factors for {sup 60}Co and 4, 10, and 18 MV x rays for concrete, steel, and lead and angles of incidence between 0{degrees} and 70{degrees}  

SciTech Connect

The attenuation of {sup 60}Co gamma rays and photons of 4, 10, and 18 MV x-ray beams by concrete, steel, and lead has been studied using the Monte Carlo technique for angles of incidence 0{degrees}, 30{degrees}, 45{degrees}, 60{degrees}, and 70{degrees}. Transmission factors have been determined down to < 2 x 10{sup {minus}5} in all cases. The results show that deviation from the obliquity factor increases with angle but is not significant for angles {le} 45{degrees}. AT 70{degrees} angle of incidence and a transmission factor of 10{sup {minus}5}, the obliquity factor varies between 1.2 and 1.9 for concrete, between 1.4 and 1.7 for steel, and between 1.4 and 1.5 for lead for the range of energies investigated. This amounts to an additional 86 and 50 cm of concrete, 25 and 23 cm of steel, and 8 and 14 cm of lead for {sup 60}Co and 18 MV x rays, respectively. The results for {sup 60}Co is concrete and lead are in good agreement with previously published experimental work. Fits to the data using mathematical models allow reconstruction of all data curves to better than 1% on average and 7% in the worst single case. 9 refs., 14 figs., 6 tabs.

Biggs, P.J. [Harvard Medical School, Boston, MA (United States)

1996-04-01T23:59:59.000Z

159

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

DOE Data Explorer (OSTI)

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

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

160

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

SciTech Connect

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

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

1997-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Effective recombination coefficient and solar zenith angle effects on low-latitude D-region ionosphere evaluated from VLF signal amplitude and its time delay during X-ray solar flares  

E-Print Network (OSTI)

Excess solar X-ray radiation during solar flares causes an enhancement of ionization in the ionospheric D-region and hence affects sub-ionospherically propagating VLF signal amplitude and phase. In first part of the work, using the well known LWPC technique, we simulated the flare induced excess lower ionospheric electron density by amplitude perturbation method. Unperturbed D-region electron density is also obtained from simulation and compared with IRI-model results. Using these simulation results and time delay as key parameters, we calculate the effective electron recombination coefficient ($\\alpha_{eff}$) at solar flare peak region. Our results match with the same obtained by other established models. In the second part, we dealt with the solar zenith angle effect on D-region during flares. We relate this VLF data with the solar X-ray data. We find that the peak of the VLF amplitude occurs later than the time of the X-ray peak for each flare. We investigate this so-called time delay ($\\bigtriangleup t$)....

Basak, Tamal

2013-01-01T23:59:59.000Z

162

X-ray beamsplitter  

DOE Patents (OSTI)

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.

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

1989-01-01T23:59:59.000Z

163

Investigations of the R5(SixGe1-x)4 Intermetallic Compounds by X-Ray Resonant Magnetic Scattering  

SciTech Connect

The XRMS experiment on the Gd{sub 5}Ge{sub 4} system has shown that, below the Neel temperature, T{sub N} = 127 K, the magnetic unit cells is the same as the chemical unit cell. From azimuth scans and the Q dependence of the magnetic scattering, all three Gd sites in the structure were determined to be in the same magnetic space group Pnma. The magnetic moments are aligned along the c-axis and the c-components of the magnetic moments at the three different sites are equal. The ferromagnetic slabs are stacked antiferromagnetically along the b-direction. They found an unusual order parameter curve in Gd{sub 5}Ge{sub 4}. A spin-reorientation transition is a possibility in Gd{sub 5}Ge{sub 4}, which is similar to the Tb{sub 5}Ge{sub 4} case. Tb{sub 5}Ge{sub 4} possesses the same Sm{sub 5}Ge{sub 4}-type crystallographic structure and the same magnetic space group as Gd{sub 5}Ge{sub 4} does. The difference in magnetic structure is that Tb{sub 5}Ge{sub 4} has a canted one but Gd{sub 5}Ge{sub 4} has nearly a collinear one in the low temperature antiferromagnetic phase. The competition between the magneto-crystalline anisotropy and the nearest-neighbor magnetic exchange interactions may allow a 3-dimensional canted antiferromagnetic structure in Tb{sub 5}Ge{sub 4}. The spin-reorientation transition in both Gd{sub 5}Ge{sub 4} and Tb{sub 5}Ge{sub 4} may arise from the competition between the magnetic anisotropy from the spin-orbit coupling of the conduction electrons and the dipolar interactions anisotropy.

Lizhi Tan

2008-08-18T23:59:59.000Z

164

Development of soft x-ray time-resolved photoemission spectroscopy system with a two-dimensional angle-resolved time-of-flight analyzer at SPring-8 BL07LSU  

Science Conference Proceedings (OSTI)

We have developed a soft x-ray time-resolved photoemission spectroscopy system using synchrotron radiation (SR) at SPring-8 BL07LSU and an ultrashort pulse laser system. Two-dimensional angle-resolved measurements were performed with a time-of-flight-type analyzer. The photoemission spectroscopy system is synchronized to light pulses of SR and laser using a time control unit. The performance of the instrument is demonstrated by mapping the band structure of a Si(111) crystal over the surface Brillouin zones and observing relaxation of the surface photo-voltage effect using the pump (laser) and probe (SR) method.

Ogawa, Manami; Yamamoto, Susumu; Nakamura, Fumitaka; Yukawa, Ryu; Fukushima, Akiko; Harasawa, Ayumi; Kakizaki, Akito; Matsuda, Iwao [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8581 (Japan); Kousa, Yuka; Kondoh, Hiroshi [Department of Chemistry, Keio University, Yokohama 223-8522 (Japan); Tanaka, Yoshihito [RIKEN/SPring-8 Center, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2012-02-15T23:59:59.000Z

165

X-ray generator  

DOE Patents (OSTI)

Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

Dawson, John M. (Los Angeles, CA)

1976-01-01T23:59:59.000Z

166

Gamma Radiation & X-Rays  

NLE Websites -- All DOE Office Websites (Extended Search)

Gamma Radiation and X-Rays 1. Gamma radiation and X-rays are electromagnetic radiation like visible light, radio waves, and ultraviolet light. These electromagnetic radiations...

167

Reply to Comment on X-ray resonant scattering studies of orbital and charge ordering in Pr[sub 1-x]Ca[sub x]MnO[sub 3].  

SciTech Connect

The interpretation given in our recent x-ray scattering study of Pr{sub 1-x}Ca{sub x}MnO{sub 3} in terms of charge and orbital ordering is questioned in the preceding Comment by Garcia and Subias. They argue that anisotropy of the charge distribution induced by local distortions gives rise to the so-called charge order reflections. In this Reply we suggest that the two different pictures are reconcilable.

Zimmermann, M. V.; Grenier, S.; Nelson, C. S.; Hill, J. P.; Gibbs, D.; Blume, M.; Casa, D.; Keimer, B.; Murakami, Y.; Kao, C.-C.; Venkataraman, C.; Gog, T.; Tomioka, Y.; Tokura, Y.; HASYLAB, DESY; BNL; Rutgers Univ.; Max-Planck-Institut; Tohoku Univ.; NSLS; JRCAT; Univ. of Tokyo

2003-09-01T23:59:59.000Z

168

Scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

Scattering Print Scattering Print When a crystalline sample is illuminated with x-rays, the x-rays are scattered (diffracted) into very specific directions with various intensities. Detectors are used to measure this "diffraction pattern," which is then processed by computers to deduce the arrangement of atoms within the crystal. Hard x-rays have wavelengths comparable to the distance between atoms. Essentially everything we know about the atomic structure of materials is based on results from x-ray and neutron diffraction. From advanced ceramics to catalysts, from semiconductor technology to the frontiers of medicine, and from new magnetic materials and devices to framework compounds used to sequester radioactive waste, crystallography using hard x-ray diffraction techniques at synchrotron radiation facilities plays a crucial role in our ability to understand and control the world in which we live.

169

Scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

Scattering Print Scattering Print When a crystalline sample is illuminated with x-rays, the x-rays are scattered (diffracted) into very specific directions with various intensities. Detectors are used to measure this "diffraction pattern," which is then processed by computers to deduce the arrangement of atoms within the crystal. Hard x-rays have wavelengths comparable to the distance between atoms. Essentially everything we know about the atomic structure of materials is based on results from x-ray and neutron diffraction. From advanced ceramics to catalysts, from semiconductor technology to the frontiers of medicine, and from new magnetic materials and devices to framework compounds used to sequester radioactive waste, crystallography using hard x-ray diffraction techniques at synchrotron radiation facilities plays a crucial role in our ability to understand and control the world in which we live.

170

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (Extended Search)

Lensless X-Ray Imaging in Lensless X-Ray Imaging in Reflection Lensless X-Ray Imaging in Reflection Print Wednesday, 26 October 2011 00:00 The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs combine the advantages of sychrotron light sources (high brightness and x-ray wavelengths relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray diffraction imaging-lensless imaging techniques that are proving to be integral to single-shot, high-resolution imaging of both complex materials and biological samples. Existing techniques are typically designed for transmission geometry, however, and use isolated objects, requiring special sample fabrication and restricting the type of samples under investigation. Recently, researchers from the ALS and the University of Oregon have shown at ALS Beamline 12.0.2 that it is possible to form x-ray holograms in reflection geometry by using the light scattered from a sample, opening the door to lensless imaging of a wealth of new material samples.

171

X-ray grid-detector apparatus  

DOE Patents (OSTI)

A hybrid grid-detector apparatus for x-ray systems wherein a microchannel plate structure has an air-interspaced grid portion and a phosphor/optical fluid-filled grid portion. The grids are defined by multiple adjacent channels separated by lead-glass septa. X-rays entering the air-interspaced grid portion at an angle of impingement upon the septa are attenuated, while non-impinging x-rays pass through to the phosphor/fluid filled portion. X-ray energy is converted to luminescent energy in the phosphor/fluid filled portion and the resultant beams of light are directed out of the phosphor/optical fluid filled portion to an imaging device.

Boone, John M. (Folsom, CA); Lane, Stephen M. (Oakland, CA)

1998-01-27T23:59:59.000Z

172

X-ray Microscopy and Imaging: 2-BM  

NLE Websites -- All DOE Office Websites (Extended Search)

BM BM Introduction The 2-BM beamline offers measurement capabilities for x-ray microtomography, x-ray topography and x-ray microdiffraction. X-ray microtomography and x-ray diffraction instruments are installed on separate optical tables for independent operation with fast switch over time. Optically-coupled high-resolution CCD system is used for microtomography and topography with up to 1 micron spatial resolution. X-ray microdiffraction setup consists of KB microfocussing mirrors (~3 micron minimum spot), four-circle Huber diffractometer, high-precision translation sample stage, two orthogonally-mounted video cameras for viewing sample, fluorescence detector (Si-drift diode) and diffraction detector (a scintillation detector or a CCD). Three different levels of monochromaticity are available. Conventional monochromatic x-rays from a double-bounced Si (111) crystal monochromator (DCM, D E/E=1E-4), wide band-pass monochromatic x-rays from a double multilayer monochromator (DMM, D E/E=1~4E-2) and pink beam. The available x-ray range is from 5 keV to 30 keV. The lower limit is due to the x-ray windows and the upper limit is due to the critical angle of the x-ray mirror. Two different coatings (Cr and Pt) for the x-ray mirror allow either 20 keV or 30 keV energy cutoff.

173

X-ray microtomography  

SciTech Connect

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.

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)

2010-12-15T23:59:59.000Z

174

Comparison of heavy charged particles and x-rays for axial tomograpic scanning  

SciTech Connect

Heavy charged particles are applicable to the problem of 3- dimensional reconstruction of electron density distributions of biological samples. The transverse uncertainty in the path of a heavy charged particle due to multiple scattering can be reduced by measuring the entrance and exit positions and angles of the particle. Patient doses for He ions and 80 keV x rays are compared under conditions suitable for imaging the human head. (auth)

Huesman, R.H.; Rosenfeld, A.H.; Solmitz, F.T.

1975-09-01T23:59:59.000Z

175

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (Extended Search)

Lensless X-Ray Imaging in Reflection Print Lensless X-Ray Imaging in Reflection Print The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs combine the advantages of sychrotron light sources (high brightness and x-ray wavelengths relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray diffraction imaging-lensless imaging techniques that are proving to be integral to single-shot, high-resolution imaging of both complex materials and biological samples. Existing techniques are typically designed for transmission geometry, however, and use isolated objects, requiring special sample fabrication and restricting the type of samples under investigation. Recently, researchers from the ALS and the University of Oregon have shown at ALS Beamline 12.0.2 that it is possible to form x-ray holograms in reflection geometry by using the light scattered from a sample, opening the door to lensless imaging of a wealth of new material samples.

176

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (Extended Search)

Lensless X-Ray Imaging in Reflection Print Lensless X-Ray Imaging in Reflection Print The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs combine the advantages of sychrotron light sources (high brightness and x-ray wavelengths relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray diffraction imaging-lensless imaging techniques that are proving to be integral to single-shot, high-resolution imaging of both complex materials and biological samples. Existing techniques are typically designed for transmission geometry, however, and use isolated objects, requiring special sample fabrication and restricting the type of samples under investigation. Recently, researchers from the ALS and the University of Oregon have shown at ALS Beamline 12.0.2 that it is possible to form x-ray holograms in reflection geometry by using the light scattered from a sample, opening the door to lensless imaging of a wealth of new material samples.

177

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging in Reflection Print X-Ray Imaging in Reflection Print The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs combine the advantages of sychrotron light sources (high brightness and x-ray wavelengths relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray diffraction imaging-lensless imaging techniques that are proving to be integral to single-shot, high-resolution imaging of both complex materials and biological samples. Existing techniques are typically designed for transmission geometry, however, and use isolated objects, requiring special sample fabrication and restricting the type of samples under investigation. Recently, researchers from the ALS and the University of Oregon have shown at ALS Beamline 12.0.2 that it is possible to form x-ray holograms in reflection geometry by using the light scattered from a sample, opening the door to lensless imaging of a wealth of new material samples.

178

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Imaging in Reflection Print X-Ray Imaging in Reflection Print The advent of x-ray free-electron laser (XFEL) light sources has led to an outburst of research activities in the field of lensless imaging. XFELs combine the advantages of sychrotron light sources (high brightness and x-ray wavelengths relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray diffraction imaging-lensless imaging techniques that are proving to be integral to single-shot, high-resolution imaging of both complex materials and biological samples. Existing techniques are typically designed for transmission geometry, however, and use isolated objects, requiring special sample fabrication and restricting the type of samples under investigation. Recently, researchers from the ALS and the University of Oregon have shown at ALS Beamline 12.0.2 that it is possible to form x-ray holograms in reflection geometry by using the light scattered from a sample, opening the door to lensless imaging of a wealth of new material samples.

179

Compton backscattered collimated x-ray source  

SciTech Connect

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

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

1998-01-01T23:59:59.000Z

180

Compton backscattered collmated X-ray source  

SciTech Connect

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

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

2000-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

APS 7-BM Beamline: X-Ray Resources  

NLE Websites -- All DOE Office Websites (Extended Search)

Useful Websites Useful Websites X-Ray Interactions with Matter from CRXO at LBNL. Intuitive interface for x-ray transmission and reflectivity for a wide range of materials. X-Ray Data Booklet from LBNL. Slightly outdated in places, but many useful tables of edge energies, fluorescence lines, and crystal lattice spacings. NIST XCOM Database. Powerful database of photoelectric absorption, elastic scattering, and Compton scattering cross-sections for a wide range of materials. X-Ray Server. Maintained by Sergey Stepanov at GMCA at the APS, this website has several powerful calculators for simulating x-ray reflection and diffraction. Software X-Ray Oriented Programs (XOP). This program, written by scientists at the ESRF and APS, is widely used in the synchrotron research community.

182

Characterization of photosynthetic supramolecular assemblies using small angle neutron scattering  

DOE Green Energy (OSTI)

We are using small angle neutron scattering (SANS) to resolve structural features of supramolecular assemblies of photosynthetic proteins in liquid and frozen solutions. SANS resolves the size, shape, and structural homogeneity of macromolecular assemblies in samples identical to those used for spectroscopic assays of photosynthetic function. Likely molecular structures of the supramolecular assemblies can be identified by comparing experimental scattering data with scattering profiles calculated for model supramolecular assemblies built from crystal structures of the individual proteins. SANS studies of the Rhodobacter sphaeroides reaction center, RC, presented here, show that the detergent solubilized RC exists in a variety of monomeric and aggregation states. The distribution between monomer and aggregate was found to depend strongly upon detergent, temperature and nature of additives, such as ethylene glycol used for low temperature spectroscopy and polyethylene glycol used for crystallization. Likely aggregate structures are being identified by fitting the experimental scattering profiles with those calculated for model aggregates built-up using the RC crystal structure. This work establishes the foundation for using SANS to identify intermediates in the RC crystallization pathways, and for determining likely structures of complexes formed between the RC and its physiological reaction partners, cytochrome c, and the LHI antenna complex.

Tiede, D.M.; Marone, P.; Wagner, A.M.; Thiyagarajan, P.

1995-12-31T23:59:59.000Z

183

X-Ray and Neutron Diffraction  

Science Conference Proceedings (OSTI)

Oct 20, 2010 ... Advanced X-Ray Scattering Techniques for Multi-Length Scale ... ?-Ti using the 3DXRD station 34-ID-E at the Advanced Photon Source, Argonne National Laboratory. ... Research at APS 34-ID-E, partly funded by BES/DOE.

184

Kinematics of Compton backscattering x-ray source for angiography  

SciTech Connect

Calculations of X-Ray production rates, energy spread, and spectrum of Compton-backscattered photons from a Free Electron Laser on an electron beam in a low energy (136-MeV) compact (8.5-m circumference) storage ring indicate that an X-Ray intensity of 34.6 10{sup 7} X-Ray photons per 0.5-mm {times} 0.5-mm pixel for Coronary Angiography near the 33.169-keV iodine K-absorption edge can be achieved in a 4-msec pulse within a scattering cone of 1-mrad half angle. This intensity, at 10-m from the photon-electron interaction point to the patient is about a factor of 10 larger than presently achieved from a 4.5-T superconducting wiggler source in the NSLS 2.5-GeV storage ring and over an area about 5 times larger. The 2.2-keV energy spread of the Compton-backscattered beam is, however, much larger than the 70-eV spread presently attained form the wiggler source and use of a monochromator. The beam spot at the 10-m interaction point-to-patient distance is 20-mm diameter; larger spots are attainable at larger distances but with a corresponding reduction in X-Ray flux. Such a facility could be an inexpensive clinical alternative to present methods of non-invasive Digital Subtraction Angiography (DSA), small enough to be deployed in an urban medical center, and could have other medical, industrial and aerospace applications. Problems with the Compton backscattering source include laser beam heating of the mirror in the FEL oscillator optical cavity, achieving a large enough X-Ray beam spot at the patient, and obtaining radiation damping of the transverse oscillations and longitudinal emittance dilution of the storage ring electron beam resulting from photon-electron collisions without going to higher electron energy where the X-Ray energy spread becomes excessive for DSA. 38 refs.

Blumberg, L.N.

1992-05-01T23:59:59.000Z

185

NUMERICAL SIMULATIONS OF CHROMOSPHERIC HARD X-RAY SOURCE SIZES IN SOLAR FLARES  

Science Conference Proceedings (OSTI)

X-ray observations are a powerful diagnostic tool for transport, acceleration, and heating of electrons in solar flares. Height and size measurements of X-ray footpoint sources can be used to determine the chromospheric density and constrain the parameters of magnetic field convergence and electron pitch-angle evolution. We investigate the influence of the chromospheric density, magnetic mirroring, and collisional pitch-angle scattering on the size of X-ray sources. The time-independent Fokker-Planck equation for electron transport is solved numerically and analytically to find the electron distribution as a function of height above the photosphere. From this distribution, the expected X-ray flux as a function of height, its peak height, and full width at half-maximum are calculated and compared with RHESSI observations. A purely instrumental explanation for the observed source size was ruled out by using simulated RHESSI images. We find that magnetic mirroring and collisional pitch-angle scattering tend to change the electron flux such that electrons are stopped higher in the atmosphere compared with the simple case with collisional energy loss only. However, the resulting X-ray flux is dominated by the density structure in the chromosphere and only marginal increases in source width are found. Very high loop densities (>10{sup 11} cm{sup -3}) could explain the observed sizes at higher energies, but are unrealistic and would result in no footpoint emission below about 40 keV, contrary to observations. We conclude that within a monolithic density model the vertical sizes are given mostly by the density scale height and are predicted smaller than the RHESSI results show.

Battaglia, M.; Kontar, E. P.; Fletcher, L.; MacKinnon, A. L., E-mail: marina.battaglia@fhnw.ch [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

2012-06-10T23:59:59.000Z

186

X-ray Science Division: Groups  

NLE Websites -- All DOE Office Websites (Extended Search)

Division: Groups Division: Groups Atomic, Molecular and Optical Physics (AMO) Primary Contact: Stephen Southworth Work focuses on understanding how strong optical and x-ray fields interact with matter, with an emphasis on photonic control of electronic, atomic and molecular motion. Chemical and Materials Science (CMS) Primary Contact: Randy Winans Research Disciplines: Chemistry, Materials Science Detectors (DET) Primary Contact: Antonino Miceli GMCA Structural Biology Facility (MX) Primary Contact: Robert Fischetti Research Disciplines: Biology, Life Sciences Imaging (IMG) Primary Contact: Francesco DeCarlo Research Disciplines: Materials Science, Biology, Physics, Life Sciences Inelastic X-ray & Nuclear Resonant Scattering (IXN) Primary Contact: Thomas Gog Research Disciplines: Condensed Matter Physics, Geophysics, Materials

187

X-ray Security Screening  

Science Conference Proceedings (OSTI)

National and International Standards for X-ray Security Screening Applications. Summary: The primary objective of this ...

2013-03-13T23:59:59.000Z

188

X-Ray Diffraction Microscopy of Magnetic Structures  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Diffraction Microscopy of Magnetic Structures Print X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing short-exposure nanoscale images of the magnetic structure of materials. The new method combines aspects of coherent x-ray diffraction, which can determine 3-D charge distributions, and resonant magnetic scattering, which is sensitive to magnetic structures. Physicists have used coherent x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of magnetic atoms, but these terms are traditionally ignored since coherent x-ray diffraction has not been used to retrieve magnetic information. Using the full formula allows for the determination of not only the electron density, but also the magnetic spin distribution and its orientation.

189

X-Ray Diffraction Microscopy of Magnetic Structures  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Diffraction Microscopy of Magnetic Structures Print X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing short-exposure nanoscale images of the magnetic structure of materials. The new method combines aspects of coherent x-ray diffraction, which can determine 3-D charge distributions, and resonant magnetic scattering, which is sensitive to magnetic structures. Physicists have used coherent x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of magnetic atoms, but these terms are traditionally ignored since coherent x-ray diffraction has not been used to retrieve magnetic information. Using the full formula allows for the determination of not only the electron density, but also the magnetic spin distribution and its orientation.

190

X-Ray Diffraction Microscopy of Magnetic Structures  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Diffraction Microscopy of Magnetic Structures Print X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing short-exposure nanoscale images of the magnetic structure of materials. The new method combines aspects of coherent x-ray diffraction, which can determine 3-D charge distributions, and resonant magnetic scattering, which is sensitive to magnetic structures. Physicists have used coherent x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of magnetic atoms, but these terms are traditionally ignored since coherent x-ray diffraction has not been used to retrieve magnetic information. Using the full formula allows for the determination of not only the electron density, but also the magnetic spin distribution and its orientation.

191

Scanning x-ray microscope  

Science Conference Proceedings (OSTI)

A scanning x-ray microscope is described including: an x-ray source capable of emitting a beam of x-rays; a collimator positioned to receive the beam of x-rays and to collimate this beam, a focusing cone means to focus the beam of x-rays, directed by the collimator, onto a focal plane, a specimen mount for supporting a specimen in the focal plane to receive the focused beam of x-rays, and x-ray beam scanning means to relatively move the specimen and the focusing cone means and collimator to scan the focused x-ray beam across the specimen. A detector is disposed adjacent the specimen to detect flourescent photons emitted by the specimen upon exposure to the focused beam of x-rays to provide an electrical output representative of this detection. Means are included for displaying and/or recording the information provided by the output from the detector, as are means for providing information to the recording and/or display means representative of the scan rate and position of the focused x-ray beam relative to the specimen whereby the recording and/or display means can correlate the information received to record and/or display quantitive and distributive information as to the quantity and distribution of elements detected in the specimen. Preferably there is provided an x-ray beam modulation means upstream, relative to the direction of emission of the xray beam, of the focusing cone means.

Wang, C.

1982-02-23T23:59:59.000Z

192

X-ray lithography source  

SciTech Connect

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

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

1991-01-01T23:59:59.000Z

193

X-ray lithography source  

DOE Patents (OSTI)

A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits is disclosed. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and eliminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an excellent moderate-priced X-ray source for lithography. 26 figures.

Piestrup, M.A.; Boyers, D.G.; Pincus, C.

1991-12-31T23:59:59.000Z

194

Kinoform optics applied to X-ray photon correlation specroscopy  

Science Conference Proceedings (OSTI)

Moderate-demagnification higher-order silicon kinoform focusing lenses have been fabricated to facilitate small-angle X-ray photon correlation spectroscopy (XPCS) experiments. The geometric properties of such lenses, their focusing performance and their applicability for XPCS measurements are described. It is concluded that one-dimensional vertical X-ray focusing via silicon kinoform lenses significantly increases the usable coherent flux from third-generation storage-ring light sources for small-angle XPCS experiments.

Sandy, A.R.; Evans-Lutterodt, K.; Narayanan, S.; Sprung, M.; Su, J.D; Isakovic, A.F.; Stein, A.

2010-03-01T23:59:59.000Z

195

Miniature x-ray source  

DOE Patents (OSTI)

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.

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)

2002-01-01T23:59:59.000Z

196

Measurement of the Weak Mixing Angle in Moller Scattering  

DOE Green Energy (OSTI)

The weak mixing parameter, sin{sup 2} {theta}{sub w}, is one of the fundamental parameters of the Standard Model. Its tree-level value has been measured with high precision at energies near the Z{sup 0} pole; however, due to radiative corrections at the one-loop level, the value of sin{sup 2} {theta}{sub w} is expected to change with the interaction energy. As a result, a measurement of sin{sup 2} {theta}{sub w} at low energy (Q{sup 2} << m{sub Z}, where Q{sup 2} is the momentum transfer and m{sub Z} is the Z boson mass), provides a test of the Standard Model at the one-loop level, and a probe for new physics beyond the Standard Model. One way of obtaining sin{sup 2} {theta}{sub w} at low energy is from measuring the left-right, parity-violating asymmetry in electron-electron (Moeller) scattering: A{sub PV} = {sigma}{sub R}-{sigma}{sub L}/{sigma}{sub R}+{sigma}{sub L}, where {sigma}{sub R} and {sigma}{sub L} are the cross sections for right- and left-handed incident electrons, respectively. The parity violating asymmetry is proportional to the pseudo-scalar weak neutral current coupling in Moeller scattering, g{sub ee}. At tree level g{sub ee} = (1/4 -sin{sup 2} {theta}{sub w}). A precision measurement of the parity-violating asymmetry in Moeller scattering was performed by Experiment E158 at the Stanford Linear Accelerator Center (SLAC). During the experiment, {approx}50 GeV longitudinally polarized electrons scattered off unpolarized atomic electrons in a liquid hydrogen target, corresponding to an average momentum transfer Q{sup 2} {approx} 0.03 (GeV/c){sup 2}. The tree-level prediction for A{sub PV} at such energy is {approx}300 ppb. However one-loop radiative corrections reduce its value by {approx}40%. This document reports the E158 results from the 2002 data collection period. The parity-violating asymmetry was found to be A{sub PV} = -160 {+-} 21 (stat.) {+-} 17 (syst.) ppb, which represents the first observation of a parity-violating asymmetry in Moeller scattering. This value corresponds to a weak mixing angle at Q{sup 2} = 0.026 (GeV/c){sup 2} of sin{sup 2} {theta}{sub w{ovr MS}} = 0.2379 {+-} 0.0016 (stat.) {+-} 0.0013 (syst.), which is -0.3 standard deviations away from the Standard Model prediction: sin{sup 2} {theta}{sub w{ovr MS}}{sup predicted} = 0.2385 {+-} 0.0006 (theory). The E158 measurement of sin{sup 2} {theta}{sub w} at a precision of {delta}(sin{sup 2} {theta}{sub w}) = 0.0020 provides new physics sensitivity at the TeV scale.

Klejda, B.

2005-01-28T23:59:59.000Z

197

Synchrotron X-ray Measurements  

Science Conference Proceedings (OSTI)

... fine structure (EXAFS) spectroscopy; (3) variable kinetic energy X-ray ... advanced materials is critical to the development and optimization of products ...

2012-10-04T23:59:59.000Z

198

X-ray Absorption Spectroscopy  

SciTech Connect

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.

Yano, Junko; Yachandra, Vittal K.

2009-07-09T23:59:59.000Z

199

Synchrotron x-ray sources and new opportunities in the soil and environmental sciences  

Science Conference Proceedings (OSTI)

This report contains the following papers: characteristics of the advanced photon source and comparison with existing synchrotron facilities; x-ray absorption spectroscopy: EXAFS and XANES -- A versatile tool to study the atomic and electronic structure of materials; applications of x-ray spectroscopy and anomalous scattering experiments in the soil and environmental sciences; X-ray fluorescence microprobe and microtomography.

Schulze, D. (Purdue Univ., Lafayette, IN (USA)); Anderson, S. (Michigan State Univ., East Lansing, MI (USA)); Mattigod, S. (Pacific Northwest Lab., Richland, WA (USA))

1990-07-01T23:59:59.000Z

200

Sharper Focusing of Hard X-rays  

NLE Websites -- All DOE Office Websites (Extended Search)

Sharper Focusing of Hard X-rays FROM: Physics News Update Number 773 #1, April 12, 2006, by Phil Schewe and Ben Stein Note: This text has been slightly modified from the original. Sharper focusing of hard x-rays has been achieved with a device developed at Argonne National Lab. Because of their high energy, x-rays are hard to focus: they can be reflected from a surface but only at a glancing angle (less than a tenth of a degree); they can be refracted but the index of refraction is very close to 1, so that making efficient lenses becomes a problem; and they can be diffracted, but the relatively thick, variable pitch grating required for focusing is tricky to achieve. The Argonne device is of the diffraction type, and it consists of a stack of alternating layers of metal and silicon, made by depositing progressively thicker layers. When the x-rays fall on such a structure, nearly edge-on, what they see is a grating (called a linear zone plate) consisting of a sort of bar-code pattern.

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Multiple wavelength x-ray monochromators  

DOE Patents (OSTI)

An 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 second 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.

Steinmeyer, P.A.

1991-01-01T23:59:59.000Z

202

Multiple wavelength x-ray monochromators  

DOE Patents (OSTI)

An 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 second 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.

Steinmeyer, P.A.

1991-12-31T23:59:59.000Z

203

Changes in delta-Plutonium due to self-irradiation aging observed by Continuous in-situ X-ray Scattering  

Science Conference Proceedings (OSTI)

The aging in plutonium is predominantly caused by its internal self-irradiation. The self-irradiation in Pu-239 is by the decay process of transmuting the Pu atom into uranium atom and emitting an {alpha}-particle. Most of the lattice damage comes from the uranium recoil resulting in Frenkel-type defects consisting of vacancies and self-interstitial atoms, helium in-growth and defect clusters and possibly even though it is not yet observed, the generation of voids. As part of the stockpile stewardship, it is important to understand the changes in the structure and microstructures and their correlations to the physical properties. Changes in the physical properties have a direct relationship to the quality of the structure, in terms of formation of defects and defect clustering, accumulation of voids, grain boundaries, phase changes and etc. which can adversely affect the stability of the material. These changes are very difficult to monitor because of the high activity of the sample, high atomic number making x-ray and synchrotron probe into the bulk very difficult (neutron probe is not feasible) and the long life time which normally requires decades to measure. In this paper we describe the development of an in-situ in-house transmission x-ray diffraction (XRD) experimental technique used to monitor the structural changes in these materials. This technique calls for a very thin sample of less that 2 mm and to accelerate the aging process due to self-irradiation, spiked alloy of 7.5 weight percent of Pu-238 is used. This is equivalent to roughly 17 times the normal rate of aging. Current results suggest that over a period of 2.8 equivalent years, an increase of 0.5% in unit cell parameter is observed. The increase appears to be an abrupt jump at about 1.1 equivalent years, brought about by the collapsing of the atoms from the interstitials to the lattice sites. Further data analysis is on the way.

Saw, C K; Chung, B W; Wall, M A

2007-01-05T23:59:59.000Z

204

Angle-resolved scattering spectroscopy of explosives using an external cavity quantum cascade laser  

Science Conference Proceedings (OSTI)

Investigation of angle-resolved scattering from solid explosives residues on a car door for non-contact sensing geometries. Illumination with a mid-infrared external cavity quantum cascade laser tuning between 7 and 8 microns was detected both with a sensitive single point detector and a hyperspectral imaging camera. Spectral scattering phenomena were discussed and possibilities for hyperspectral imaging at large scattering angles were outlined.

Suter, Jonathan D.; Bernacki, Bruce E.; Phillips, Mark C.

2012-04-01T23:59:59.000Z

205

X-ray diffuse scattering measurements of chemical short-range order and lattice strains in a highly magnetostrictive Fe0.813Ga0.187 alloy in an applied magnetic field  

SciTech Connect

The rapid growth of the magnetostriction coefficient of ferromagnetic Fe1?xGax alloys that occurs at a composition range from 0X-ray diffuse scattering measurements sensitive to the atomic short-range ordering and lattice strain were performed on a quenched 18.7 at. % Ga alloy and show no dependence on the application of a magnetic field. This negative result sets limits on the role of nanoscale precipitates in magnetostriction.

Du, Yingzhou; Lograsso, Thomas A.; McQueeney, Robert J.

2012-06-28T23:59:59.000Z

206

A highly modular beamline electrostatic levitation facility, optimized for in situ high-energy x-ray scattering studies of equilibrium and supercooled liquids  

Science Conference Proceedings (OSTI)

High-energy x-ray diffraction studies of metallic liquids provide valuable information about structural evolution on the atomic length scale, leading to insights into the origin of the nucleation barrier and the processes of supercooling and glass formation. The containerless processing of the beamline electrostatic levitation (BESL) facility allows coordinated thermophysical and structural studies of equilibrium and supercooled liquids to be made in a contamination-free, high-vacuum ({approx}10{sup -8} Torr) environment. To date, the incorporation of electrostatic levitation facilities into synchrotron beamlines has been difficult due to the large footprint of the apparatus and the difficulties associated with its transportation and implementation. Here, we describe a modular levitation facility that is optimized for diffraction studies of high-temperature liquids at high-energy synchrotron beamlines. The modular approach used in the apparatus design allows it to be easily transported and quickly setup. Unlike most previous electrostatic levitation facilities, BESL can be operated by a single user instead of a user team.

Mauro, N.A.; Kelton, K.F. (WU)

2011-10-27T23:59:59.000Z

207

Introduction to Small-Angle Neutron Scattering and Neutron ...  

Science Conference Proceedings (OSTI)

... where g(r) is the pair correlation function for the scattering objects and lng(r) is directly related to the potential energy function that describes the ...

2010-04-29T23:59:59.000Z

208

Small and Intermediate-Angle Scattering Instruments for Materials ...  

Science Conference Proceedings (OSTI)

It is becoming clear that even at such low power sources, we can conduct ... Scattering Methods for Investigations on Magnetic Thin Film Nanostructures.

209

Bio-SANS: the Biological Small-Angle Neutron Scattering Instrument...  

NLE Websites -- All DOE Office Websites (Extended Search)

Biological Small-Angle Neutron Scattering Instrument at HFIR Detector tanks for the new SANS instruments at HFIR. The Bio-SANS detector is on the right. Detector tanks for the SANS...

210

Miniature x-ray source  

DOE Patents (OSTI)

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.

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

2000-01-01T23:59:59.000Z

211

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

DOE Patents (OSTI)

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.

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

1985-01-01T23:59:59.000Z

212

Tokamak x ray diagnostic instrumentation  

SciTech Connect

Three classes of x-ray diagnostic instruments enable measurement of a variety of tokamak physics parameters from different features of the x-ray emission spectrum. (1) The soft x-ray (1 to 50 keV) pulse-height-analysis (PHA) diagnostic measures impurity concentrations from characteristic line intensities and the continuum enhancement, and measures the electron temperature from the continuum slope. (2) The Bragg x-ray crystal spectrometer (XCS) measures the ion temperature and neutral-beam-induced toroidal rotation velocity from the Doppler broadening and wavelength shift, respectively, of spectral lines of medium-Z impurity ions. Impurity charge state distributions, precise wavelengths, and inner-shell excitation and recombination rates can also be studied. X rays are diffracted and focused by a bent crystal onto a position-sensitive detector. The spectral resolving power E/..delta..E is greater than 10/sup 4/ and time resolution is 10 ms. (3) The x-ray imaging system (XIS) measures the spatial structure of rapid fluctuations (0.1 to 100 kHZ) providing information on MHD phenomena, impurity transport rates, toroidal rotation velocity, plasma position, and the electron temperature profile. It uses an array of silicon surface-barrier diodes which view different chords of the plasma through a common slot aperture and operate in current (as opposed to counting) mode. The effectiveness of shields to protect detectors from fusion-neutron radiation effects has been studied both theoretically and experimentally.

Hill, K.W.; Beiersdorfer, P.; Bitter, M.; Fredrickson, E.; Von Goeler, S.; Hsuan, H.; Johnson, L.C.; Liew, S.L.; McGuire, K.; Pare, V.

1987-01-01T23:59:59.000Z

213

X-ray Transition Energies Search Form  

Science Conference Proceedings (OSTI)

[skip navigation] X-ray Transition Energies Database Main Page Search for X-ray transition energies by element(s), transition ...

214

Femtosecond Time-Delay X-ray Holography  

NLE Websites -- All DOE Office Websites (Extended Search)

Time-Delay X-ray Holography Time-Delay X-ray Holography X-ray free-electron lasers (XFELs) will produce photon pulses with a unique and desirable combination of properties. Their short X-ray wavelengths allow penetration into materials and the ability to probe structure at and below the nanometer scale. Their ultra-short duration gives information about this structure at the fundamental time-scales of atoms and molecules. The extreme intensity of the pulses will allow this information to be acquired in a single shot, so that these studies can be carried out on non-repeatable processes or on weakly-scattering objects that will be modified by the pulse. A fourth property of XFEL pulses is their high transverse coherence, which brings the promise of decades of innovation in visible optics to the X-ray regime, such as holography, interferometry, and laser-based imaging. Making an effective use of XFEL pulses, however, will benefit from innovations that are new to both X-ray science and coherent optics. One such innovation is the new method of time-delay X-ray holography [i], recently demonstrated at the FLASH FEL at DESY in Hamburg, to measure the evolution of objects irradiated by intense pulses.

215

Small-angle Compton Scattering to Determine the Depth of a Radioactive Source in Matter  

SciTech Connect

A gamma-ray peak in a spectrum is often accompanied by a discontinuity in the Compton continuum at the peak. The Compton continuum results from Compton scattering in the detector. The discontinuity at a peak results from small-angle Compton scattering by the gamma rays in matter situated directly between the gamma-ray source and the detector. The magnitude of this discontinuity with respect to the gamma-ray peak is therefore an indicator of the amount of material or shielding between the gamma-ray source and the detector. This small-angle scattering was used to determine the depth of highly-enriched uranium (HEU) solution standards in a concrete floor mockup. The empirical results of the use of this small-angle scattering discontinuity in a concrete floor experiment will be described. A Monte Carlo calculation of the experiment will also be described. In addition, the depth determined from small-angle scattering was used in conjunction with differential attenuation to more accurately measure the uranium content of the mockup. Following these empirical results, the theory of small-angle scattering will be discussed. The magnitude of the discontinuity compared to the peak count rate is directly related to the depth of the gamma-ray source in matter. This relation can be described by relatively simple mathematical expressions. This is the first instance that we are aware of in which the small-angle Compton scattering has been used to determine the depth of a radioactive source. Furthermore this is the first development of the theoretical expressions for the magnitude of the small-angle scattering discontinuity.

Oberer, R. B.; Gunn, C. A.; Chiang, L. G.; Valiga, R. E.; Cantrell, J. A.

2011-04-01T23:59:59.000Z

216

Real time x-ray studies during nanostructure formation on silicon via low energy ion beam irradiation using ultrathin iron films  

SciTech Connect

Real time grazing incidence small angle x-ray scattering and x-ray fluorescence (XRF) are used to elucidate nanodot formation on silicon surfaces during low energy ion beam irradiation of ultrathin iron-coated silicon substrates. Four surface modification stages were identified: (1) surface roughening due to film erosion, (2) surface smoothing and silicon-iron mixing, (3) structure formation, and (4) structure smoothing. The results conclude that 2.5 Multiplication-Sign 10{sup 15} iron atoms in a 50 nm depth triggers surface nanopatterning with a correlated nanodots distance of 25 nm. Moreover, there is a wide window in time where the surface can have correlated nanostructures even after the removal of all the iron atoms from the sample as confirmed by XRF and ex-situ x-ray photoelectron spectroscopy (XPS). In addition, in-situ XPS results indicated silicide formation, which plays a role in the structure formation mechanism.

El-Atwani, Osman [School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Suslova, Anastassiya; Gonderman, Sean; Fowler, Justin; El-Atwani, Mohamad [School of Nuclear Engineering, Purdue University, West Lafayette, Indiana, 47907 (United States); DeMasi, Alexander; Ludwig, Karl [Physics Department, Boston University, Boston, Massachusetts 02215 (United States); Paul Allain, Jean [School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); School of Nuclear Engineering, Purdue University, West Lafayette, Indiana, 47907 (United States)

2012-12-24T23:59:59.000Z

217

Compact x-ray source and panel  

SciTech Connect

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

Sampayon, Stephen E. (Manteca, CA)

2008-02-12T23:59:59.000Z

218

X-ray emission from colliding laser plasmas  

SciTech Connect

Colliding Au, CD and Ti-Cr plasmas have been generated by illuminating two opposing foils each with a {approximately} 100J, 0.5 nsec, 2{omega} Nd-glass laser beam from the Trident laser facility at Los Alamos. The plasmas are being used to study plasma interactions which span the parameter regime from interpenetrating to collisional stagnation. X-ray emission during the laser target interaction and the subsequent collision is used to diagnose the initial plasma conditions and the colliding plasma properties. X-ray instrumentation consists of a 100 ps gated x-ray pinhole imager, a time-integratcd bremsstrahlung x-ray spectrograph and a gated x-ray spectrograph used to record isoelectronic spectra from the Ti-Cr plasmas. The imager has obtained multi-frame images of the collision and therefore, a measure of the stagnation length which is a function of the ion charge state and density and a strong function of the electron temperature. Other instrumentation includes a Thomson scattering spectrometer with probe beam, neutron detectors used to monitor the CD coated foil collisions and an ion spectrometer. We will describe the current status of the experiments and current results with emphasis on the x-ray emission diagnostics. We will also briefly describe the modeling using Lasnex and ISIS, a particle-in-cell code with massless fluid electrons and inter particle (classical) collisions.

Wilke, M.; Obst, A.W.; Winske, D. [and others

1995-09-01T23:59:59.000Z

219

Enhanced Electron Efficiency in an X-ray Diode  

SciTech Connect

The goal for this research is to optimize the XRD structure and usage configurations and increase the efficiency of the XRD. This research was successful in optimizing the XRD structure and usage configurations, thus creating a high efficiency XRD. Best efficiency occurs when there is an angle between the photocathode and incident X-rays.

K. Sun, L. MacNeil

2010-05-20T23:59:59.000Z

220

Pitch angle scattering of relativistic electrons from stationary magnetic waves: Continuous Markov process and quasilinear theory  

Science Conference Proceedings (OSTI)

We develop a Markov process theory of charged particle scattering from stationary, transverse, magnetic waves. We examine approximations that lead to quasilinear theory, in particular the resonant diffusion approximation. We find that, when appropriate, the resonant diffusion approximation simplifies the result of the weak turbulence approximation without significant further restricting the regime of applicability. We also explore a theory generated by expanding drift and diffusion rates in terms of a presumed small correlation time. This small correlation time expansion leads to results valid for relatively small pitch angle and large wave energy density - a regime that may govern pitch angle scattering of high-energy electrons into the geomagnetic loss cone.

Lemons, Don S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2012-01-15T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis  

SciTech Connect

This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

Meyer, Matthew W. [Ames Laboratory

2013-03-14T23:59:59.000Z

222

Microgap x-ray detector  

DOE Patents (OSTI)

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

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

1994-01-01T23:59:59.000Z

223

Coulomb Correction to the Screening Angle of the Moliere Multiple Scattering Theory  

E-Print Network (OSTI)

High-energy Coulomb correction to the screening angular parameter of the Moliere multiple scattering theory is found. Numerical calculations are presented in the range of nuclear charge from Z=4 to Z=82. Comparison with the Moliere result for the screening angle reveals up to 30% deviation from it for sufficiently heavy elements of the target material.

E. A. Kuraev; O. O. Voskresenskaya; A. V. Tarasov

2012-11-29T23:59:59.000Z

224

Small-Angle Neutron Scattering Studies of a-Si:H and a-Si:D  

DOE Green Energy (OSTI)

The heterogeneity of hydrogen and deuterium on the nanometer scale has been probed by samll-angle neutron scattering (SANS) from a-Si:H and a-Si:D films. Films were depsoited by two techniques, plasma-enhanced chemical vapor deposition (PECVD) and hot-wire chemical vapor deposition (HWCVD) using conditions that yield high quality films and devices.

Williamson, D. L.; Marr, D. W. M.; Nelson, B. P.; Iwaniczko, E.; Yang, J.; Yan, B.; Guha, S.

2000-01-01T23:59:59.000Z

225

Chest x-Rays | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Chest x-Rays Chest x-Rays Chest x-Rays Chest X-ray B-Reading The B-reading is a special reading of a standard chest x-ray film performed by a physician certified by the National Institute for Occupational Safety and Health (NIOSH). The reading looks for changes on the chest x-ray that may indicate exposure and disease caused by agents such as asbestos or silica. The B-reading is considered a special reading because doctors who are certified by NIOSH to perform B-readings use a specific protocol to read and record the findings as developed by the International Labour Organization (ILO). The ILO's protocol provides rules for systematically examining the x-ray in a step-by-step method and recording certain abnormalities or changes on the chest x-ray that can be attributable to

226

Spectral analysis of X-ray binaries  

E-Print Network (OSTI)

In this thesis, I present work from three separate research projects associated with observations of X-ray binaries. Two of those revolve around spectral characteristics of neutron star low-mass X-ray binaries (NS-LMXBs), ...

Fridriksson, Joel Karl

2011-01-01T23:59:59.000Z

227

EQ-SANS: the Extended Q-Range Small-Angle Neutron Scattering Diffractometer  

NLE Websites -- All DOE Office Websites (Extended Search)

The Extended Q-Range Small-Angle Neutron Scattering Diffractometer at SNS The Extended Q-Range Small-Angle Neutron Scattering Diffractometer at SNS Extended Q-Range Small Angle Diffractometer EQ-SANS detector array The EQ-SANS Diffractometer is designed to study non-crystalline, nano-sized materials in solid, liquid, or gas forms such as polymers, micelles, proteins, and other large biological molecular complexes in solution. It offers high neutron flux, high wavelength resolution (precision), and wide Q-coverage. EQSANS is located on beam line 6, viewing the top-downstream, coupled supercritical hydrogen moderator. It has a curved multichannel beam bender to avoid the direct line of sight of the moderator, which cleans out the background from the prompt neutron pulse quite effectively. The cutoff wavelength of the optics is ~1.5 Å. Above this minimum wavelength, the

228

Modelling the X-ray polarimetric signatures of complex geometry: the case study of the "changing look" AGN NGC 1365  

E-Print Network (OSTI)

"Changing look" Active Galactic Nuclei (AGN) are a subset of Seyfert galaxies characterized by rapid transitions between Compton-thin and Compton-thick regimes. In their Compton-thin state, the central engine is less obscured, hence spectroscopy or timing observations can probe their innermost structures. However, it is not clear if the observed emission features and the Compton hump are associated with relativistic reflection onto the accretion disc, or complex absorption by distant, absorbing gas clouds passing by the observer's line-of-sight. Here, we investigate these two scenarios under the scope of X-ray polarimetry, providing the first polarisation predictions for an archetypal "changing look" AGN: NGC 1365. We explore the resulting polarisation emerging from lamp-post emission and scattering off an accretion disc in the immediate vicinity of a supermassive black hole. The computed polarisation signatures are compared to the results of an absorption-dominated model, where high column density gas partially covers the central source. While the shape of the polarisation spectrum is similar, the two models differ in net polarisation percentage, with the relativistic reflection scenario producing significantly stronger polarisation. Additionally, the variation of the polarisation position angle is distinctly different between both scenarios: the reflection-dominated model produces smooth rotations of the polarisation angle with photon energy whereas circumnuclear absorption causes an orthogonal switch of the polarisation angle between the soft and the hard X-ray bands. By comparing the predicted polarisation of NGC 1365 to the detectability levels of X-ray polarimetry mission concepts proposed in the past, we demonstrate that with a large, soft X-ray observatory or a medium-sized mission equipped with a hard (6 - 35 keV) polarimeter, the correct interpretation would be unambiguous.

Frederic Marin; Delphine Porquet; Rene W. Goosmann; Michal Dovciak; Fabio Muleri; Nicolas Grosso; Vladimir Karas

2013-09-06T23:59:59.000Z

229

Cryotomography x-ray microscopy state  

Science Conference Proceedings (OSTI)

An x-ray microscope stage enables alignment of a sample about a rotation axis to enable three dimensional tomographic imaging of the sample using an x-ray microscope. A heat exchanger assembly provides cooled gas to a sample during x-ray microscopic imaging.

Le Gros, Mark (Berkeley, CA); Larabell, Carolyn A. (Berkeley, CA)

2010-10-26T23:59:59.000Z

230

Concave Accretion Discs and X-ray Reprocessing  

E-Print Network (OSTI)

Spectra of Seyfert Is are commonly modelled as emission from an X-ray illuminated flat accretion disc orbiting a central black hole. This provides both a reprocessed and direct component of the X-ray emission as required by observations of individual objects and possibly a fraction of the cosmological X-ray background. There is some observational motivation to at least consider the role that an effectively concave disc surface might play: (1) a reprocessed fraction $\\gsim 1/2$ in some Seyferts and possibly in the X-ray background, and (2) the commonality of a sharp iron line peak for Seyferts at 6.4KeV despite a dependence of peak location on inclination angle for flat disc models. Here it is shown that a concave disc may not only provide a larger total fraction of reprocessed photons, but can also reprocess a much larger fraction of photons in its outer regions when compared to a flat disc. This reduces the sensitivity of the 6.4KeV peak location to the inner disc inclination angle because the outer regions are less affected by Doppler and gravitational effects. If the X-ray source is isotropic, the reprocessed fraction is directly determined by the concavity. If the X-ray source is anisotropic, the location of iron line peak can still be determined by concavity but the total reflected fraction need not be as large as for the isotropic emitter case. The geometric calculations herein are applicable to general accretion disc systems illuminated from the center.

Eric G. Blackman

1999-01-16T23:59:59.000Z

231

Research article: Monte Carlo-based rigid body modelling of large protein complexes against small angle scattering data  

Science Conference Proceedings (OSTI)

We present a modular, collaborative, open-source architecture for rigid body modelling based upon small angle scattering data, named sas_rigid. It is designed to provide a fast and extensible scripting interface using the easy-to-learn Python programming ... Keywords: Hemocyanin, Monte Carlo with simulated annealing, Rigid body modelling, Small angle scattering (SAS)

Christian Meesters; Bruno Pairet; Anja Rabenhorst; Heinz Decker; Elmar Jaenicke

2010-06-01T23:59:59.000Z

232

X-ray transmissive debris shield  

DOE Patents (OSTI)

An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

Spielman, R.B.

1996-05-21T23:59:59.000Z

233

X-ray transmissive debris shield  

DOE Patents (OSTI)

An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

Spielman, Rick B. (Albuquerque, NM)

1996-01-01T23:59:59.000Z

234

Concave accretion discs and X-ray reprocessing  

E-Print Network (OSTI)

Spectra of Seyfert Is are commonly modelled as emission from an X-ray illuminated flat accretion disc orbiting a central black hole. This provides both a reprocessed and direct component of the X-ray emission as required by observations of individual objects and possibly of the cosmological X-ray background. However, there is observational motivation to consider the role that an effectively concave disc surface might play: (1) a reprocessed fraction $> 1$ in individual Seyferts and the X-ray background, and (2) the commonality of a sharp iron line peak for Seyferts at 6.4KeV despite a strong dependence of peak location on inclination angle for flat disc models. Here it is shown that a concave disc may not only provide a larger total fraction of reprocessed photons but can also reprocess a much larger fraction of photons in its outer regions when compared to a flat disc. This reduces the sensitivity of the 6.4KeV peak location to the inner disc inclination angle because the outer regions are less affected by D...

Blackman, E G

1999-01-01T23:59:59.000Z

235

Directional x-ray dark-field imaging of strongly ordered systems  

Science Conference Proceedings (OSTI)

Recently a novel grating based x-ray imaging approach called directional x-ray dark-field imaging was introduced. Directional x-ray dark-field imaging yields information about the local texture of structures smaller than the pixel size of the imaging system. In this work we extend the theoretical description and data processing schemes for directional dark-field imaging to strongly scattering systems, which could not be described previously. We develop a simple scattering model to account for these recent observations and subsequently demonstrate the model using experimental data. The experimental data includes directional dark-field images of polypropylene fibers and a human tooth slice.

Jensen, Torben Haugaard; Feidenhans'l, Robert [Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Bech, Martin; Pfeiffer, Franz [Department of Physics, Technical University of Munich, 85747 Garching (Germany); Zanette, Irene; Weitkamp, Timm [European Synchrotron Radiation Facility, 38043 Grenoble (France); David, Christian; Rutishauser, Simon [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Deyhle, Hans [Biomaterials Science Center, University of Basel, 4031 Basel (Switzerland); Institute for Materials Science, School of Dental Medicine, University of Basel, 4031 Basel (Switzerland); Reznikova, Elena; Mohr, Juergen [Karlsruhe Institute of Technology, Institute for Microstructure Technology, 76021 Karlsruhe (Germany)

2010-12-01T23:59:59.000Z

236

The General-Purpose Small-Angle Neutron Scattering Diffractometer at HFIR -  

NLE Websites -- All DOE Office Websites (Extended Search)

General-Purpose Small-Angle Neutron Scattering Diffractometer at HFIR General-Purpose Small-Angle Neutron Scattering Diffractometer at HFIR Instrument scientist Ken Littrell at GP-SANS. Instrument scientist Ken Littrell at GP-SANS. The General-Purpose Small-Angle Neutron Scattering Diffractometer (GP-SANS) instrument is optimized for providing information about structure and interactions in materials in the size range of 0.5 - 200 nm. It has a cold neutron flux on sample and capabilities comparable to those of the best SANS instruments worldwide, including a wide range of neutron wavelengths λ 5 - 30 Å, resolution Δλ ⁄ λ 9=45%, and a 1m2 area detector with 5 × 5mm2 pixel resolution with a maximum counting capability of up to 2.5 kHz. The sample-to-detector distance can be varied from 1 to 20 m, and the detector can be offset horizontally by up to 45 cm, allowing

237

Diffuse Scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

Diffuse Scattering Diffuse Scattering * Anticipatory (trick) question: If you have an x-ray or neutron detector looking at a small sample volume, which will scatter more x- rays or neutrons into the detector 1 atom 100 atoms or 1000 atoms? X-ray or neutron beam Answer: Depends! Diffuse Scattering Gene E. Ice Materials Science and Technology Division Oak Ridge National Laboratory, USA National School on Neutron and X-ray Scattering ORNL/SNS June 2011 Presentation concentrates year graduate-level course into 1 hour * Skip mathematical complexities * Expose to range of applications * Develop intuition for length scales * Talk like x-ray/neutron scattering guru - Reciprocal space - Debye Temperature - Laue monotonic - Krivoglaz defects of 1st/2nd kinds! Great for cocktail parties or impressing attractive strangers-

238

X-ray transmissive debris shield  

DOE Patents (OSTI)

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

Spielman, Rick B. (Albuquerque, NM)

1994-01-01T23:59:59.000Z

239

NIST X-Ray Transition Energies  

Science Conference Proceedings (OSTI)

... with the International System of measurement ... titled "X-ray transition energies: new approach ... and by NIST's Systems Integration for Manufacturing ...

2011-12-09T23:59:59.000Z

240

X-ray Line Profile Analysis  

Science Conference Proceedings (OSTI)

... Magnetic Composite Materials · X-Ray Studies of Structural Effects Induced by Pulsed (30 Tesla), High Magnetic Fields at the Advanced Photon Source ...

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

NIST: X-Ray Mass Attenuation Coefficients  

Science Conference Proceedings (OSTI)

... NIST reserves the right to charge for these data in the ... ?/? and the mass energy-absorption coefficient ... The tables cover energies of the photon (x-ray ...

2011-12-09T23:59:59.000Z

242

Lensless X-Ray Imaging in Reflection  

NLE Websites -- All DOE Office Websites (Extended Search)

relevant to atomic and molecular phenomena) with the advantages of visible-light lasers (highly coherent beams). All of these characteristics are important for coherent x-ray...

243

Hard X-Ray Quad Collimator  

Technology Development and Commercialization Division One of the best ways to obtain small?size x?ray beams for structural biology research is to ...

244

Fast Lidar and Radar Multiple-Scattering Models. Part II: Wide-Angle Scattering Using the Time-Dependent Two-Stream Approximation  

Science Conference Proceedings (OSTI)

Spaceborne lidar returns from liquid water clouds contain significant contributions from photons that have experienced many wide-angle multiple-scattering events, resulting in returns appearing to originate from far beyond the end of the cloud. A ...

Robin J. Hogan; Alessandro Battaglia

2008-12-01T23:59:59.000Z

245

The second-order differential phase contrast and its retrieval for imaging with x-ray Talbot interferometry  

SciTech Connect

Purpose: The x-ray differential phase contrast imaging implemented with the Talbot interferometry has recently been reported to be capable of providing tomographic images corresponding to attenuation-contrast, phase-contrast, and dark-field contrast, simultaneously, from a single set of projection data. The authors believe that, along with small-angle x-ray scattering, the second-order phase derivative {Phi}{sup Double-Prime }{sub s}(x) plays a role in the generation of dark-field contrast. In this paper, the authors derive the analytic formulae to characterize the contribution made by the second-order phase derivative to the dark-field contrast (namely, second-order differential phase contrast) and validate them via computer simulation study. By proposing a practical retrieval method, the authors investigate the potential of second-order differential phase contrast imaging for extensive applications. Methods: The theoretical derivation starts at assuming that the refractive index decrement of an object can be decomposed into {delta}={delta}{sub s}+{delta}{sub f}, where {delta}{sub f} corresponds to the object's fine structures and manifests itself in the dark-field contrast via small-angle scattering. Based on the paraxial Fresnel-Kirchhoff theory, the analytic formulae to characterize the contribution made by {delta}{sub s}, which corresponds to the object's smooth structures, to the dark-field contrast are derived. Through computer simulation with specially designed numerical phantoms, an x-ray differential phase contrast imaging system implemented with the Talbot interferometry is utilized to evaluate and validate the derived formulae. The same imaging system is also utilized to evaluate and verify the capability of the proposed method to retrieve the second-order differential phase contrast for imaging, as well as its robustness over the dimension of detector cell and the number of steps in grating shifting. Results: Both analytic formulae and computer simulations show that, in addition to small-angle scattering, the contrast generated by the second-order derivative is magnified substantially by the ratio of detector cell dimension over grating period, which plays a significant role in dark-field imaging implemented with the Talbot interferometry. Conclusions: The analytic formulae derived in this work to characterize the second-order differential phase contrast in the dark-field imaging implemented with the Talbot interferometry are of significance, which may initiate more activities in the research and development of x-ray differential phase contrast imaging for extensive preclinical and eventually clinical applications.

Yang Yi; Tang Xiangyang [Imaging and Medical Physics, Department of Radiology and Imaging Sciences, Emory University School of Medicine, 1701 Uppergate Dr., C-5018, Atlanta, Georgia 30322 (United States)

2012-12-15T23:59:59.000Z

246

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

E-Print Network (OSTI)

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

Krauss, Miriam Ilana

2007-01-01T23:59:59.000Z

247

X-Ray Multilayer Database from the LBL Center for X-Ray Optics (CXRO)  

DOE Data Explorer (OSTI)

An important activity of the Center for X-ray Optics (CXRO) is research on x-ray mirrors and their use in optical devices to focus and deflect x-ray beams. The two kinds of mirrors most widely used are glancing incidence reflectors and multilayer coatings. The X-Ray Multilayer Database is based on the results of surveys taken at the biennial Physics of X-Ray Multilayer Structures conferences. It contains measured x-ray reflectances reported for various multilayers. The database is provided as a service to the x-ray and multilayer research communities and is intended to reflect the state-of-the-art in multilayer x-ray mirrors. (Specialized Interface)

248

A Precision Low-Energy Measurement of the Weak Mixing Angle in Moller Scattering  

DOE Green Energy (OSTI)

The E-158 experiment at the Stanford Linear Accelerator Center (SLAC) measures the parity-violating cross-section asymmetry in electron-electron (Moeller) scattering at low Q{sup 2}. This asymmetry, whose Standard Model prediction is roughly -150 parts per billion (ppb), is directly proportional to (1-4 sin{sup 2} {theta}{sub W}), where {theta}{sub W} is the weak mixing angle. Measuring this asymmetry to within 10% provides an important test of the Standard Model at the quantum loop level and probes for new physics at the TeV scale. The experiment employs the SLAC 50 GeV electron beam, scattering it off a liquid hydrogen target. A system of magnets and collimators is used to isolate and focus the Moeller scattering events into an integrating calorimeter. The electron beam is generated at the source using a strained, gradient-doped GaAs photocathode, which produces roughly 5 x 10{sup 11} electrons/pulse (at a beam rate of 120 Hz) with {approx} 80% longitudinal polarization. The helicity of the beam can be rapidly switched, eliminating problems associated with slow drifts. Helicity-correlations in the beam parameters (charge, position, angle and energy) are minimized at the source and corrected for using precision beam monitoring devices.

Mastromarino, P.

2005-01-26T23:59:59.000Z

249

Materials Analysis by Soft x-ray Scanning Transmission X-ray ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Optical and X-ray Imaging Techniques for Material Characterization.

250

Elevation angle alignment of quasi optical receiver mirrors of collective Thomson scattering diagnostic by sawtooth measurements  

Science Conference Proceedings (OSTI)

Localized measurements of the fast ion velocity distribution function and the plasma composition measurements are of significant interest for the fusion community. Collective Thomson scattering (CTS) diagnostics allow such measurements with spatial and temporal resolution. Localized measurements require a good alignment of the optical path in the transmission line. Monitoring the alignment during the experiment greatly benefits the confidence in the CTS measurements. An in situ technique for the assessment of the elevation angle alignment of the receiver is developed. Using the CTS diagnostic on TEXTOR without a source of probing radiation in discharges with sawtooth oscillations, an elevation angle misalignment of 0.9 Degree-Sign was found with an accuracy of 0.25 Degree-Sign .

Moseev, D. [FOM DIFFER - Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Nieuwegein (Netherlands); Max-Planck-Institut fuer Plasmaphysik, Euratom Association-IPP, 85748 Garching (Germany); Meo, F.; Korsholm, S. B.; Leipold, F.; Michelsen, P. K.; Nielsen, S. K.; Salewski, M.; Stejner, M. [Association EURATOM - DTU, Department of Physics, Technical University of Denmark, Riso Campus, 4000 Roskilde (Denmark); Bindslev, H. [Faculty of Science and Technology, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Furtula, V. [Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Kantor, M. [FOM DIFFER - Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Nieuwegein (Netherlands); FZ Juelich GmbH, EURATOM, Trilateral Euregio Cluster, D-52425 Juelich (Germany); Ioffe Institute, RAS, Saint Petersburg 194021 (Russian Federation)

2012-10-15T23:59:59.000Z

251

Initial characterization of mudstone nanoporosity with small angle neutron scattering using caprocks from carbon sequestration sites.  

Science Conference Proceedings (OSTI)

Geological carbon sequestration relies on the principle that CO{sub 2} injected deep into the subsurface is unable to leak to the atmosphere. Structural trapping by a relatively impermeable caprock (often mudstone such as a shale) is the main trapping mechanism that is currently relied on for the first hundreds of years. Many of the pores of the caprock are of micrometer to nanometer scale. However, the distribution, geometry and volume of porosity at these scales are poorly characterized. Differences in pore shape and size can cause variation in capillary properties and fluid transport resulting in fluid pathways with different capillary entry pressures in the same sample. Prediction of pore network properties for distinct geologic environments would result in significant advancement in our ability to model subsurface fluid flow. Specifically, prediction of fluid flow through caprocks of geologic CO{sub 2} sequestration reservoirs is a critical step in evaluating the risk of leakage to overlying aquifers. The micro- and nanoporosity was analyzed in four mudstones using small angle neutron scattering (SANS). These mudstones are caprocks of formations that are currently under study or being used for carbon sequestration projects and include the Marine Tuscaloosa Group, the Lower Tuscaloosa Group, the upper and lower shale members of the Kirtland Formation, and the Pennsylvanian Gothic shale. Total organic carbon varies from shale and Kirtland Formation, respectively. Neutrons effectively scatter from interfaces between materials with differing scattering length density (i.e. minerals and pores). The intensity of scattered neutrons, I(Q), where Q is the scattering vector, gives information about the volume of pores and their arrangement in the sample. The slope of the scattering data when plotted as log I(Q) vs. log Q provides information about the fractality or geometry of the pore network. Results from this study, combined with high-resolution TEM imaging, provide insight into the differences in volume and geometry of porosity between these various mudstones.

McCray, John (Colorado School of Mines); Navarre-Sitchler, Alexis (Colorado School of Mines); Mouzakis, Katherine (Colorado School of Mines); Heath, Jason E.; Dewers, Thomas A.; Rother, Gernot (Oak Ridge National Laboratory)

2010-11-01T23:59:59.000Z

252

Use of Small Angle Neutron Scattering to Study Various Properties of Wool and Mohair Fibres  

SciTech Connect

To maintain a competitive edge in the wool and mohair industry, a detailed knowledge and understanding of the properties of wool fibres is essential. Standard techniques are used to determine fibre diameter, length and strength; however, properties such as hydroscopicity, lustre and changes in fibre structure following chemical or mechanical treatment are not so well understood. The unique capabilities of small angle neutron scattering to study changes in the supermolecular structure of wool fibres, particularly at the level of the microfibril-matrix complex, have been used to provide previously unknown features of the fibres. The results of these studies are presented.

Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa); Toeroek, Gy. [Research Institute for Solid State Physics and Optics, H-1525 Budapest, POB 49 (Hungary)

2011-12-13T23:59:59.000Z

253

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

SciTech Connect

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

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

2012-05-10T23:59:59.000Z

254

Precision Beam Parameter Monitoring in a Measurement of the Weak Mixing Angle in Moeller Scattering  

DOE Green Energy (OSTI)

A precision measurement of the parity nonconserving left-right asymmetry, A{sub LR}, in Moeller scattering (e{sup -}e{sup -} {yields} e{sup -}e{sup -}) is currently in progress at the Stanford Linear Accelerator Center (SLAC). This experiment, labeled SLAC-E158, scatters longitudinally polarized electrons off atomic electrons in an unpolarized hydrogen target at a Q{sup 2} of 0.03 (GeV/c){sup 2}. The asymmetry, which is the fractional difference in the scattering cross-sections, measures the effective pseudo-scalar weak neutral current coupling, g{sub ee}, governing Moeller scattering. This quantity is in turn proportional to (1/4 - sin{sup 2} {theta}{sub w}), where {theta}{sub w} is the electroweak mixing angle. The goal is to measure the asymmetry to a precision of 1 x 10{sup -8} which corresponds to {delta}(sin{sup 2} {theta}{sub w}) {approx} 0.0007. Since A{sub LR} is a function of the cross-sections, and the cross-sections depend on the beam parameters, the desired precision of A{sub LR} places stringent requirements on the beam parameters. This paper investigates the requirements on the beam parameters and discusses the means by which they are monitored and accounted for.

Cooke, M.S.

2005-04-11T23:59:59.000Z

255

Ultrafast three-dimensional x-ray computed tomography  

SciTech Connect

X-ray computed tomography (CT) is a well established visualization technique in medicine and nondestructive testing. However, since CT scanning requires sampling of radiographic projections from different viewing angles, common CT systems with mechanically moving parts are too slow for dynamic imaging, for instance of multiphase flows or live animals. Here, we introduce an ultrafast three-dimensional x-ray CT method based on electron beam scanning, which achieves volume rates of 500 s{sup -1}. Primary experiments revealed the capability of this method to recover the structure of phase boundaries in gas-solid and gas-liquid two-phase flows, which undergo three-dimensional structural changes in the millisecond scale.

Bieberle, Martina; Barthel, Frank; Hampel, Uwe [Institute of Safety Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Menz, Hans-Juergen; Mayer, Hans-Georg [Institute of Nuclear Technology and Energy Systems, University of Stuttgart, 70569 Stuttgart (Germany)

2011-01-17T23:59:59.000Z

256

Fiber fed x-ray/gamma ray imaging apparatus  

SciTech Connect

X-ray/gamma ray imaging apparatus is disclosed for detecting the position, energy, and intensity of x-ray/gamma ray radiation comprising scintillation means disposed in the path of such radiation and capable of generating photons in response to such radiation; first photodetection means optically bonded to the scintillation means and capable of generating an electrical signal indicative of the intensity, and energy of the radiation detected by the scintillation means; second photodetection means capable of generating an electrical signal indicative of the position of the radiation in the radiation pattern; and means for optically coupling the scintillation means to the second photodetection means. The photodetection means are electrically connected to control and storage means which may also be used to screen out noise by rejecting a signal from one photodetection means not synchronized to a signal from the other photodetection means; and also to screen out signals from scattered radiation.

Hailey, Charles J. (San Francisco, CA); Ziock, Klaus-Peter (Livermore, CA)

1992-01-01T23:59:59.000Z

257

APS Bending Magnet X-rays and  

NLE Websites -- All DOE Office Websites (Extended Search)

Irradiation of Nd-Fe-B Permanent Magnets with Irradiation of Nd-Fe-B Permanent Magnets with APS Bending Magnet X-rays and 60 Co γ-rays J. Alderman and P.K. Job APS Operations Division Advanced Photon Source J. Puhl Ionizing Radiation Division National Institute of Standards and Technology June 2000 Table of Contents Introduction Radiation-Induced Demagnetization of Permanent Magnets Resources Required γ-ray Irradiation Results and Analysis of γ-ray Irradiation X-ray Irradiation Results and Analysis of X-ray Irradiation Summary and Conclusions Acknowledgements References Tables and Figures Introduction The Advanced Photon Source (APS), as well as other third-generation synchrotron light sources, uses permanent magnets in the insertion devices to produce x-rays for scientific

258

High-Resolution X-ray Spectroscopy  

Science Conference Proceedings (OSTI)

... In support of these efforts, we also maintain laboratory x-ray sources from 1 keV to 300 keV, energy and intensity calibration facilities, and a vacuum ...

2013-02-26T23:59:59.000Z

259

X-ray image intensifier phosphor  

DOE Patents (OSTI)

Y/sub 1-x/Gd/sub x/.PO$sub 4$:Tb$sup 3+$ is an effective phosphor for use in X-ray intensifier screens and in nuclear radiation detection systems.

D' Silva, A.P.; Fassel, V.A.

1975-12-01T23:59:59.000Z

260

Kaonic Atom X?ray Spectra  

Science Conference Proceedings (OSTI)

In kaonic atoms energy displacement and broadening of states result from the strong interaction. The most simple kaonic atoms like kaonic hydrogen and deuterium open the possibility to measure this strong interaction induced shift and width by x?ray spectroscopy. In the SIDDHARTA experiment al LNF (Frascati) the DA?NE electron?positron collider delivers nearly mono?energetic negatively charged kaons from ? meson decay. This unique kaon source is used to form kaonic atoms. New high performance x?ray detectors (silicon drift detectors) arranged in an array allow x?ray spectroscopy with high energy resolution combined with timing capability. High precision x?ray measurements like SIDDHARTA at LNF will open the way to study the low energy regime of the strong force in the antikaon?nucleon interaction. The experiment and its current status is presented in this talk.

J. Marton; on behalf of the SIDDHARTA Collaboration

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

World's First Hard X-ray Laser  

NLE Websites -- All DOE Office Websites (Extended Search)

LCLS is the world's most powerful X-ray laser. Its highly focused beam, which arrives in staccato bursts a few quadrillionths of a second long, allows researchers to probe complex,...

262

X-Ray Nanoimaging: Instruments and Methods  

NLE Websites -- All DOE Office Websites (Extended Search)

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

263

SCATMECH: Polarized Light Scattering C++ Class Library ...  

Science Conference Proceedings (OSTI)

... cout tab // Scattering angle (theta) tab // Scattering angle (phi) tab // Principal angle of ...

2012-09-27T23:59:59.000Z

264

X-Ray Emission from Compact Sources  

SciTech Connect

This paper presents a review of the physical parameters of neutron stars and black holes that have been derived from X-ray observations. I then explain how these physical parameters can be used to learn about the extreme conditions occurring in regions of strong gravity, and present some recent evidence for relativistic effects seen in these systems. A glossary of commonly used terms and a short tutorial on the names of X-ray sources are also included.

Cominsky, L

2004-03-23T23:59:59.000Z

265

Argonne CNM: X-Ray Microscopy Capabilities  

NLE Websites -- All DOE Office Websites (Extended Search)

X-Ray Microscopy Facilities X-Ray Microscopy Facilities The Hard X-Ray Nanoprobe (HXN) facility provides scanning fluorescence, scanning diffraction, and full-field transmission and tomographic imaging capabilities with a spatial resolution of 30 nm over a spectral range of 6-12 keV. Modes of Operation Full-Field Transmission Imaging and Nanotomography X-ray transmission imaging uses both the absorption and phase shift of the X-ray beam by the sample as contrast mechanisms. Absorption contrast is used to map the sample density. Elemental constituents can be located by using differential edge contrast in this mode. Phase contrast can be highly sensitive to edges and interfaces even when the X-ray absorption is weak. These contrast mechanisms are exploited to image samples rapidly in full-field transmission mode under various environmental conditions, or combined with nanotomography methods to study the three-dimensional structure of complex and amorphous nanomaterials with the HXN.

266

X-ray Synchrotron Radiation in a Plasma Wiggler  

SciTech Connect

A relativistic electron beam can radiate due to its betatron motion inside an ion channel. The ion channel is induced by the electron bunch as it propagates through an underdense plasma. In the theory section of this thesis the formation of the ion channel, the trajectories of beam electrons inside the ion channel, the radiation power and the radiation spectrum of the spontaneous emission are studied. The comparison between different plasma wiggler schemes is made. The difficulties in realizing stimulated emission as the beam traverses the ion channel are investigated, with particular emphasis on the bunching mechanism, which is important for the ion channel free electron laser. This thesis reports an experiment conducted at the Stanford Linear Accelerator Center (SLAC) to measure the betatron X-ray radiations for the first time. They first describe the construction and characterization of the lithium plasma source. In the experiment, the transverse oscillations of the SLAC 28.5 GeV electron beam traversing through a 1.4 meter long lithium plasma source are clearly seen. These oscillations lead to a quadratic density dependence of the spontaneously emitted betatron X-ray radiation. The divergence angle of the X-ray radiation is measured. The absolute photon yield and the spectral brightness at 14.2 KeV photon energy are estimated and seen to be in reasonable agreement with theory.

Wang, Shuoquin; /UCLA /SLAC, SSRL

2005-09-27T23:59:59.000Z

267

Copper Ridges Nearly Double X-ray Sensor Performance  

Science Conference Proceedings (OSTI)

... Physics Letters,* can measure X-ray energies with an ... X-rays and measure the energy based on ... by NASA and the NIST Office of Microelectronics ...

2011-10-03T23:59:59.000Z

268

Sandia National Laboratories X-ray Tube with Magnetic Electron ...  

... for the U.S. Department of Energy’s National ... high average power large area X-ray tube provides increased X-ray generation efficiency through ...

269

XIPE: the X-ray Imaging Polarimetry Explorer  

E-Print Network (OSTI)

X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and temporal variability measurements and to imaging, allows a wealth of physical phenomena in astrophysics to be studied. X-ray polarimetry investigates the acceleration process, for example, including those typical of magnetic reconnection in solar flares, but also emission in the strong magnetic fields of neutron stars and white dwarfs. It detects scattering in asymmetric structures such as accretion disks and columns, and in the so-called molecular torus and ionization cones. In addition, it allows fundamental physics in regimes of gravity and of magnetic field intensity not accessible to experiments on the Earth to be probed. Finally, models that describe fundamental interactions (e.g. quantum gravity and the extension of the Standard Model) can be tested. We describe in this paper the X-ray Imaging Polarimetry Explorer (XIPE), proposed in June 2012 to the first ESA call for a small mission with a launch in 2017 but not selected. XIPE ...

Soffitta, Paolo; Bellazzini, Ronaldo; Braga, João; Costa, Enrico; Fraser, George W; Gburek, Szymon; Huovelin, Juhani; Matt, Giorgio; Pearce, Mark; Poutanen, Juri; Reglero, Victor; Santangelo, Andrea; Sunyaev, Rashid A; Tagliaferri, Gianpiero; Weisskopf, Martin; Aloisio, Roberto; Amato, Elena; Attiná, Primo; Axelsson, Magnus; Baldini, Luca; Basso, Stefano; Bianchi, Stefano; Blasi, Pasquale; Bregeon, Johan; Brez, Alessandro; Bucciantini, Niccoló; Burderi, Luciano; Burwitz, Vadim; Casella, Piergiorgio; Churazov, Eugene; Civitani, Marta; Covino, Stefano; da Silva, Rui Miguel Curado; Cusumano, Giancarlo; Dadina, Mauro; D'Amico, Flavio; De Rosa, Alessandra; Di Cosimo, Sergio; Di Persio, Giuseppe; Di Salvo, Tiziana; Dovciak, Michal; Elsner, Ronald; Eyles, Chris J; Fabian, Andrew C; Fabiani, Sergio; Feng, Hua; Giarrusso, Salvatore; Goosmann, René W; Grandi, Paola; Grosso, Nicolas; Israel, Gianluca; Jackson, Miranda; Kaaret, Philip; Karas, Vladimir; Kuss, Michael; Lai, Dong; La Rosa, Giovanni; Larsson, Josefin; Larsson, Stefan; Latronico, Luca; Maggio, Antonio; Maia, Jorge; Marin, Frédéric; Massai, Marco Maria; Mineo, Teresa; Minuti, Massimo; Moretti, Elena; Muleri, Fabio; O'Dell, Stephen L; Pareschi, Giovanni; Peres, Giovanni; Pesce, Melissa; Petrucci, Pierre-Olivier; Pinchera, Michele; Porquet, Delphine; Ramsey, Brian; Rea, Nanda; Reale, Fabio; Rodrigo, Juana Maria; Ró?a?ska, Agata; Rubini, Alda; Rudawy, Pawel; Ryde, Felix; Salvati, Marco; Júnior, Valdivino Alexandre de Santiago; Sazonov, Sergey; Sgró, Carmelo; Silver, Eric; Spandre, Gloria; Spiga, Daniele; Stella, Luigi; Tamagawa, Toru; Tamborra, Francesco; Tavecchio, Fabrizio; Dias, Teresa Teixeira; van Adelsberg, Matthew; Wu, Kinwah; Zane, Silvia

2013-01-01T23:59:59.000Z

270

LATE-TIME DETECTIONS OF THE X-RAY AFTERGLOW OF GRB 060729 WITH CHANDRA-THE LATEST DETECTIONS EVER OF AN X-RAY AFTERGLOW  

SciTech Connect

We report on five Chandra observations of the X-ray afterglow of the gamma-ray burst (GRB) 060729 performed between 2007 March and 2008 May. In all five observations, the afterglow is clearly detected. The last Chandra pointing was performed on 2008 May 4, 642 days after the burst-the latest detection of a GRB X-ray afterglow ever. A reanalysis of the Swift XRT light curve together with the three detections by Chandra in 2007 reveals a break at {approx}1.0 Ms after the burst with a slight steepening of the decay slope from alpha = 1.32 to 1.61. This break coincides with a significant hardening of the X-ray spectrum, consistent with a cooling break in the wind medium scenario, in which the cooling frequency of the afterglow crosses the X-ray band. The last two Chandra observations in 2007 December and 2008 May provide evidence for another break at about one year after the burst. If interpreted as a jet break, this late-time break implies a jet half-opening angle of {approx}14{sup 0} for a wind medium. Alternatively, this final break may have a spectral origin, in which case no jet break has been observed and the half-opening angle of the jet of GRB 060729 must be larger than {approx}15{sup 0} for a wind medium. We compare the X-ray afterglow of GRB 060729 in a wind environment with other bright X-ray afterglows, in particular GRBs 061121 and 080319B, and discuss why the X-ray afterglow of GRB 060729 is such an exceptionally long-lasting event.

Grupe, Dirk; Burrows, David N.; Wu Xuefeng; Wang Xiangyu; Garmire, Gordon; Nousek, John A. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Zhang Bing [Department of Physics, University of Nevada, Las Vegas, NV 89154 (United States); Liang Enwei [Department of Physics, Guangxi University, Nanning 530004 (China); Gehrels, Neil [Astrophysics Science Division, Astroparticle Physics Laboratory, Code 661, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ricker, George R.; Bautz, Marshall W., E-mail: grupe@astro.psu.ed [Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139-4307 (United States)

2010-03-10T23:59:59.000Z

271

Waveguide detection of right-angle-scattered light in flow cytometry  

DOE Patents (OSTI)

A transparent flow cell is used as an index-guided optical waveguide. A detector for the flow cell but not the liquid stream detects the Right-Angle-Scattered (RAS) Light exiting from one end of the flow cell. The detector(s) could view the trapped RAS light from the flow cell either directly or through intermediate optical light guides. If the light exits one end of the flow cell, then the other end of the flow cell can be given a high-reflectivity coating to approximately double the amount of light collected. This system is more robust in its alignment than the traditional flow cytometry systems which use imaging optics, such as microscope objectives.

Mariella, Jr., Raymond P. (Danville, CA)

2000-01-01T23:59:59.000Z

272

Small angle neutron scattering analysis of novel carbons for lithium secondary batteries.  

DOE Green Energy (OSTI)

Small angle neutron scattering analyses of carbonaceous materials used as anodes in lithium ion cells have been performed. The carbons have been synthesized using pillared clays (PILCs) as inorganic templates. Pillared clays are layered silicates whose sheets have been permanently propped open by sets of thermally stable molecular props. The calcined PILC was loaded with five different organic precursors and heated at 700 C under nitrogen. When the inorganic pillars were removed by acid treatment, carbon sheets are produced with holes. The fitting of the data in the high q region suggested that the carbon sheets have voids with radii ranging from 4 to 8 {angstrom}. Similar radii were obtained for the PILC and PILC/organic precursor, which suggests that the carbon was well distributed in the clay prior to pyrolysis.

Sandi, G.; Thiyagarajan, P.; Winans, R.; Carrado, K.

1998-01-14T23:59:59.000Z

273

A Precision Measurement of the Weak Mixing Angle in Moller Scattering at Low Q^2  

DOE Green Energy (OSTI)

The electroweak theory has been probed to a high level of precision at the mass scale of the Z{sup 0} through the joint contributions of LEP at CERN and the SLC at SLAC. The E158 experiment at SLAC complements these results by measuring the weak mixing angle at a Q{sup 2} of 0.026 (GeV/c){sup 2}, far below the weak scale. The experiment utilizes a 48 GeV longitudinally polarized electron beam on unpolarized atomic electrons in a target of liquid hydrogen to measure the parity-violating asymmetry A{sup PV} in Moeller scattering. The tree-level prediction for A{sup PV} is proportional to 1-4 sin{sup 2} {theta}{sub W}. Since sin{sup 2} {theta}{sub W} {approx} 0.25, the effect of radiative corrections is enhanced, allowing the E158 experiment to probe for physics effects beyond the Standard Model at the TeV scale. This work presents the results from the first two physics runs of the experiment, covering data collected in the year 2002. The parity-violating asymmetry A{sup PV} was measured to be A{sup PV} = -158 ppb {+-} 21 ppb (stat) {+-} 17 ppb (sys). The result represents the first demonstration of parity violation in Moeller scattering. The observed value of A{sup PV} corresponds to a measurement of the weak mixing angle of sin{sup 2} {theta}{sub W}{sup eff} = 0.2380 {+-} 0.0016(stat) {+-} 0.0013(sys), which is in good agreement with the theoretical prediction of sin{sup 2} {theta}{sub W}{sup eff} = 0.2385 {+-} 0.0006 (theory).

Jones, G.

2005-01-28T23:59:59.000Z

274

The effect of the shape function on small-angle scattering analysis by the maximum entropy method  

SciTech Connect

Analysis of small-angle scattering data to obtain a particle size distribution is dependent upon the shape function used to model the scattering. Using a maximum entropy analysis of small-angle scattering data, the effect of shape function selection on obtained size distribution is demonstrated using three different shape functions to describe the same scattering data from each of two steels. The alloys have been revealed by electron microscopy to contain a distribution of randomly oriented and mainly non-interacting, irregular, ellipsoidal precipitates. Comparison is made between the different forms of the shape function. Effect of an incident wavelength distribution is also shown. The importance of testing appropriate shape functions and validating these against other microstructural studies is discussed.

Jemian, P.R. [Argonne National Lab., IL (United States); Allen, A.J. [Univ. of Maryland, College Park, MD (United States). Department of Physics]|[National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1992-09-15T23:59:59.000Z

275

The Road to Ultrahigh-Resolution X-ray Spectrometers | Advanced Photon  

NLE Websites -- All DOE Office Websites (Extended Search)

How Atoms Behave: Characteristics of Microstructural Avalanches How Atoms Behave: Characteristics of Microstructural Avalanches Iodate Refuses to Intimidate Creating the Heart of a Planet in the Heart of a Gem How a Powerful Antibody Neutralizes HIV Taking a Page from Nature to Build Better Nanomaterials Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed The Road to Ultrahigh-Resolution X-ray Spectrometers NOVEMBER 22, 2011 Bookmark and Share Basic phenomena underlying the AD&AT x-ray optics. In x-ray Bragg diffraction from atomic planes composing nonzero angle η to the crystal entrance face, the crystal acts (a) like an optical prism dispersing the photons into a divergent x-ray fan with photons of different energies E

276

Time-domain sampling of x-ray pulses using an ultrafast sample response  

Science Conference Proceedings (OSTI)

We employ the ultrafast response of a 15.4 nm thin SrRuO{sub 3} layer grown epitaxially on a SrTiO{sub 3} substrate to perform time-domain sampling of an x-ray pulse emitted from a synchrotron storage ring. Excitation of the sample with an ultrashort laser pulse triggers coherent expansion and compression waves in the thin layer, which turn the diffraction efficiency on and off at a fixed Bragg angle during 5 ps. This is significantly shorter than the duration of the synchrotron x-ray pulse of 100 ps. Cross-correlation measurements of the ultrafast sample response and the synchrotron x-ray pulse allow to reconstruct the x-ray pulse shape.

Gaal, P.; Shayduk, R. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Wilhelm-Conrad-Roentgen Campus, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Schick, D.; Herzog, M.; Bojahr, A.; Goldshteyn, J.; Navirian, H. A.; Leitenberger, W. [Institut fuer Physik und Astronomie, Universitaet Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam (Germany); Vrejoiu, I. [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Khakhulin, D.; Wulff, M. [European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz, 38000 Grenoble (France); Bargheer, M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Wilhelm-Conrad-Roentgen Campus, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Institut fuer Physik und Astronomie, Universitaet Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam (Germany)

2012-12-10T23:59:59.000Z

277

Cooling flows, central galaxy--cluster alignments, X-ray absorption and dust  

E-Print Network (OSTI)

We present the analysis of pointed ROSAT PSPC observations of five of the most luminous, intermediate redshift ($0.1 cooling flows. The alignment between CCGs and their host clusters has been investigated. For those clusters with cooling flows, the position angles of the X-ray emission from the clusters and the optical emission from the CCGs agrees within 5 degrees. For the one probable non-cooling flow cluster in the sample, Abell 2208, the alignment is significantly poorer. We examine the evidence for intrinsic X-ray absorption in the clusters. The X-ray spectra for Abell 1068 and Abell 1664 show that the cooling flows in these clusters are intrinsically absorbed by equivalent hydrogen column densities $\\geq 10^{21} atom cm$^{-2}$. The optical spectra of the CCGs in these clusters exhibit substantial intrinsic reddening, at levels consistent with the X-ray absorption results if standard dust to gas ratios are assumed.

S. W. Allen; A. C. Fabian; A. C. Edge; H. Bohringer; D. A. White

1995-03-28T23:59:59.000Z

278

X-Ray Light Sources | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

X-Ray Light Sources X-Ray Light Sources Scientific User Facilities (SUF) Division SUF Home About User Facilities X-Ray Light Sources Neutron Scattering Facilities Nanoscale Science Research Centers Electron-Beam Microcharacterization Centers Accelerator & Detector Research & Development Principal Investigators' Meetings Scientific Highlights Construction Projects BES Home User Facilities X-Ray Light Sources Print Text Size: A A A RSS Feeds FeedbackShare Page This activity supports the operation of five DOE light sources. The unique properties of synchrotron radiation include its continuous spectrum, high flux and brightness, and in the case of the Linac Coherent Light Source, high coherence, which makes it an indispensable tool in the exploration of matter. The wavelengths of the emitted photons span a range of dimensions

279

Radiographic X-Ray Pulse Jitter  

Science Conference Proceedings (OSTI)

The Dual Beam Radiographic Facility consists of two identical radiographic sources. Major components of the machines are: Marx generator, water-filled pulse-forming line (PFL), water-filled coaxial transmission line, three-cell inductive voltage adder, and rod-pinch diode. The diode pulse has the following electrical specifications: 2.25-MV, 60-kA, 60-ns. Each source has the following x-ray parameters: 1-mm-diameter spot size, 4-rad at 1 m, 50-ns full width half max. The x-ray pulse is measured with PIN diode detectors. The sources were developed to produce high resolution images on single-shot, high-value experiments. For this application it is desirable to maintain a high level of reproducibility in source output. X-ray pulse jitter is a key metric for analysis of reproducibility. We will give measurements of x-ray jitter for each machine. It is expected that x-ray pulse jitter is predominantly due to PFL switch jitter, and therefore a correlation of the two will be discussed.

Mitton, C. V., Good, D. E., Henderson, D. J., Hogge, K. W.

2011-01-15T23:59:59.000Z

280

Frontiers in X-Ray Science  

Science Conference Proceedings (OSTI)

The year 2010 marked the fiftieth anniversary of the optical laser and the first anniversary of the world's first hard x-ray free-electron laser, the Linac Coherent Light Source (LCLS) at SLAC. This exciting, new accelerator-based source of x-rays provides peak brilliances roughly a billion times greater than currently available from synchrotron sources such as the Advanced Photon Source at Argonne, and thus explores a qualitatively different parameter space. This talk will describe the first experiments at the LCLS aimed at understanding the nature of high intensity x-ray interactions, related applications in ultrafast imaging on the atomic scale and sketch nascent plans for the extension of both linac and storage-ring based photon sources.

Linda Young

2011-02-23T23:59:59.000Z

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281

Multicontrast x-ray computed tomography imaging using Talbot-Lau interferometry without phase stepping  

SciTech Connect

Purpose: The purpose of this work is to demonstrate that multicontrast computed tomography (CT) imaging can be performed using a Talbot-Lau interferometer without phase stepping, thus allowing for an acquisition scheme like that used for standard absorption CT. Methods: Rather than using phase stepping to extract refraction, small-angle scattering (SAS), and absorption signals, the two gratings of a Talbot-Lau interferometer were rotated slightly to generate a moire pattern on the detector. A Fourier analysis of the moire pattern was performed to obtain separate projection images of each of the three contrast signals, all from the same single-shot of x-ray exposure. After the signals were extracted from the detector data for all view angles, image reconstruction was performed to obtain absorption, refraction, and SAS CT images. A physical phantom was scanned to validate the proposed data acquisition method. The results were compared with a phantom scan using the standard phase stepping approach. Results: The reconstruction of each contrast mechanism produced the expected results. Signal levels and contrasts match those obtained using the phase stepping technique. Conclusions: Absorption, refraction, and SAS CT imaging can be achieved using the Talbot-Lau interferometer without the additional overhead of long scan time and phase stepping.

Bevins, Nicholas; Zambelli, Joseph; Li Ke; Qi Zhihua; Chen Guanghong [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States) and Department of Radiology, University of Wisconsin-Madison, 600 Highland Avenue, Madison, Wisconsin 53792 (United States)

2012-01-15T23:59:59.000Z

282

Radiobiological studies using gamma and x rays.  

Science Conference Proceedings (OSTI)

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

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

2013-02-01T23:59:59.000Z

283

Non-Invasive Early Detection and Molecular Analysis of Low X-ray Dose  

NLE Websites -- All DOE Office Websites (Extended Search)

Invasive Early Detection & Molecular Analysis of Low X-ray Dose Effects Invasive Early Detection & Molecular Analysis of Low X-ray Dose Effects in the Lens Lee Goldstein Boston University School of Medicine Abstract Purpose: The lens is a highly-ordered tissue with unique optical properties and exquisite radiosensitivity. The focus of this project is to evaluate radiation cataract dose response and mechanisms associated with low-linear energy transfer (LET) X-rays. We aim to investigate the natural history of Rayleigh light scattering changes in pre-cataractous lenses of mice exposed to radiations using a fully-validated, performance-tested quasi-elastic light scattering (QLS) instrument developed by Dr. Goldstein and colleagues at Boston University. This innovative laser-based technology quantitatively assays pre-cataractous molecular pathology in the lenses of living mice

284

Analysis of hard X-ray eclipse in SS433 from INTEGRAL observations  

E-Print Network (OSTI)

The analysis of hard X-ray INTEGRAL observations (2003-2008) of superaccreting galactic microquasar SS433 at precessional phases of the source with the maximum disk opening angle is carried out. It is found that the shape and width of the primary X-ray eclipse is strongly variable suggesting additional absorption in dense stellar wind and gas outflows from the optical A7I-component and the wind-wind collision region. The independence of the observed hard X-ray spectrum on the accretion disk precessional phase suggests that hard X-ray emission (20-100 keV) is formed in an extended, hot, quasi-isothermal corona, probably heated by interaction of relativistic jet with inhomogeneous wind outflow from the precessing supercritical accretion disk. A joint modeling of X-ray eclipsing and precessional hard X-ray variability of SS433 revealed by INTEGRAL by a geometrical model suggests the binary mass ratio $q=m_x/m_v\\simeq 0.25\\div 0.5$. The absolute minimum of joint orbital and precessional $\\chi^2$ residuals is reac...

Cherepashchuk, A M; Postnov, K A; Antokhina, E A; Molkov, S V

2009-01-01T23:59:59.000Z

285

Development of a Novel Tunable X-Ray Source for the RPI-LINAC  

Science Conference Proceedings (OSTI)

This document summarizes the results of a three year effort to develop a parametric x-ray (PXR) source. The emphasis of this research was to demonstrate production of high yield monoenergetic x-rays. Production of PXR is accomplished by placing a crystal in a relativistic electron beam. The process was first demonstrated in 1985 in Russia. Numerous papers were written about the characteristics of PXR from both experimental and theoretical perspectives. The advantage of PXR over other monoenergetic x-ray sources is that it is produced at large angle relative to the electron beam and at high intensity. None of the previous work described in the literature capitalized on this effect to study what is required in order to generate an effective monoenergetic x-ray source that can be used for practical applications. The work summarized here describes the process done in order to optimize the PXR production process by selecting an appropriate crystal and the optimal conditions. The research focused on production of 18 keV x-rays which are suitable for mammography however the results are not limited to this application or energy range. We are the first group to demonstrate x-ray imaging using PXR. Such sources can improve current medical imaging modalities. More research is required in order to design a prototype of a compact source.

Y. Danon; R.C. Block

2004-11-30T23:59:59.000Z

286

The Soft-X-Ray Spectral Shape of X-Ray-Weak Seyferts  

E-Print Network (OSTI)

(I) We observed eight Seyfert~2s and two X--ray--weak Seyfert~1/QSOs with the ROSAT PSPC, and one Seyfert~2 with the ROSAT HRI. These targets were selected from the Extended 12\\um\\ Galaxy Sample. (II) Both Seyfert~1/QSOs vary by factors of 1.5---2. The photon indices steepen in the more luminous state, consistent with the variability being mainly due to the softest X--rays, which are confined to a size of less than a parsec. (III) Both the Seyfert~2s and Seyfert~1/QSOs are best fit with a photon index of $\\Gamma\\sim3$, which is steeper than the canonical value of $\\Gamma\\sim1.7$ measured for X--ray--strong Seyferts by ROSAT and at higher energies. Several physical explanations are suggested for the steeper slopes of X--ray--weak objects. (IV) We observed one Seyfert~2, NGC~5005, with the ROSAT HRI, finding about 13\\% of the soft X--rays to come from an extended component. This and other observations suggest that different components to the soft X--ray spectrum of some, if not all, X--ray--weak Seyferts may come from spatially distinct regions.

Brian Rush; Matthew A. Malkan

1995-07-27T23:59:59.000Z

287

High-Energy X-ray Studies of Real Materials Under Real Conditions and in Real Time  

SciTech Connect

High-energy x-rays from 3rd generation synchrotron sources, including the APS, possess a unique combination of high penetration power and high spatial, reciprocal space, and temporal resolution. These characteristics can be exploited to non-destructively measure phase, texture and strain distributions under extreme environments including thermo-mechanical loading, high-pressure, irradiation and supercritical environments. Over the past several years, the 1-ID beamline has developed a number of programs for these purposes, namely (i) high-energy diffraction microscopy, in which grain and sub-grain volumes are mapped in polycrystalline aggregates, and (ii) combined small-and wide-angle x-ray scattering which permits information over a broad range of length scales to be collected from the same (micron-level) volume. These programs have been increasingly used to test and extend predictive simulations of materials behavior over size scales ranging from nm to mm. Select studies will be presented including nucleation and growth of nanomaterials, void and structural evolution in complex composites under thermo-mechanical and irradiated environments, and microstructural changes in layered systems including thermal-barrier coatings, batteries and fuel cells. Finally, extension of these programs, through the planned APS upgrade, to higher spatio-temporal resolution will be described.

Almer, Jonathan (ANL)

2011-05-11T23:59:59.000Z

288

Soluble Hydrogen-bonding Interpolymer Complexes in Water: A Small-Angle Neutron Scattering Study  

E-Print Network (OSTI)

The hydrogen-bonding interpolymer complexation between poly(acrylic acid) (PAA) and the poly(N,N-dimethylacrylamide) (PDMAM) side chains of the negatively charged graft copolymer poly(acrylic acid-co-2-acrylamido-2-methyl-1-propane sulfonic acid)-graft-poly(N, N dimethylacrylamide) (P(AA-co-AMPSA)-g-PDMAM), containing 48 wt % of PDMAM, and shortly designated as G48, has been studied by small-angle neutron scattering in aqueous solution. Complexation occurs at low pH (pH hydrogen-bonding interpolymer complexes, whose radius is estimated to be around 165 A. As these particles involve more than five graft copolymer chains, they act as stickers between the anionic chains of the graft copolymer backbone. This can explain the characteristic thickening observed in past rheological measurements with these mixtures in the semidilute solution, with decreasing pH. We have also examined the influence of pH and PAA molecular weight on the formation of these nanoparticles.

Maria Sotiropoulou; Julian Oberdisse; Georgios Staikos

2006-04-03T23:59:59.000Z

289

Soft x-ray laser microscope  

Science Conference Proceedings (OSTI)

The program consisted of two phases (Phase I and Phase II). The goal of the Phase I (first year program) was to design and construct the Soft X-ray Laser Contact Microscope. Such microscope was constructed and adapted to PPL's 18.2nm soft X-ray Laser (SXL), which in turn was modified and prepared for microscopy experiments. Investigation of the photoresist response to 18.2nm laser radiation and transmissivity of 0.1m thick silicion-nitride (Si[sub 3]N[sub 4]) windows were important initial works. The goal of the first year of Phase II was to construct X-ray contact microscope in combination with existing optical phase microscope, already used by biologists. In the second year of Phase II study of dehydrated Horeseshoe Crab and Hela cancer cells were performed with COXRALM. Also during Phase II, the Imaging X-Ray Laser Microscope (IXRALM) was designed and constructed. This paper describes the development of each of the microscopes and their application for research.

Suckewer, P.I.

1990-10-01T23:59:59.000Z

290

Scanner for integrated x-ray breast tomosynthesis and molecular breast imaging tomosynthesis  

Science Conference Proceedings (OSTI)

A dual modality tomosynthesis (DMT) breast scanner has been developed that combines x-ray breast tomosynthesis (XBT) and molecular breast imaging tomosynthesis (MBIT) on a common upright gantry to obtain co-registered structural and functional tomosynthesis ... Keywords: breast tomosynthesis, hybrid scanners, limited angle SPECT, molecular breast imaging, multimodality imaging

Mark B. Williams; Patricia G. Judy; Zongyi Gong; Audrey E. Graham; Stan Majewski; Spencer Gunn

2010-06-01T23:59:59.000Z

291

Active probing of cloud multiple scattering, optical depth, vertical thickness, and liquid water content using wide-angle imaging LIDAR.  

SciTech Connect

At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is the essence of our unique instrument, Wide Angle Imaging Lidar (WAIL). In effect, WAIL produces wide-field (60-degree full-angle) 'movies' of the scattering process and records the cloud's radiative Green functions. A direct data product of WAIL is the distribution of photon path lengths resulting from multiple scattering in the cloud. Following insights from diffusion theory, we can use the measured Green functions to infer the physical thickness and optical depth of the cloud layer, and, from there, estimate the volume-averaged liquid water content. WAIL is notable in that it is applicable to optically thick clouds, a regime in which traditional lidar is reduced to ceilometry. Here we present recent WAIL data oti various clouds and discuss the extension of WAIL to full diurnal monitoring by means of an ultra-narrow magneto-optic atomic line filter for daytime measurements.

Love, Steven P.; Davis, A. B. (Anthony B.); Rohde, C. A. (Charles A.); Tellier, L. L. (Larry L.); Ho, Cheng,

2002-01-01T23:59:59.000Z

292

Rise time measurement for ultrafast X-ray pulses  

Science Conference Proceedings (OSTI)

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

Celliers, Peter M. (Berkeley, CA); Weber, Franz A. (Oakland, CA); Moon, Stephen J. (Tracy, CA)

2005-04-05T23:59:59.000Z

293

Rise Time Measurement for Ultrafast X-Ray Pulses  

DOE Patents (OSTI)

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

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

2005-04-05T23:59:59.000Z

294

X-ray flashes and X-ray rich gamma ray bursts. Memorie della Societa’ Astronomica Italiana  

E-Print Network (OSTI)

Abstract. X-ray flashes are detected in the Wide Field Cameras on BeppoSAX in the energy range 2-25 keV as bright X-ray sources lasting of the order of minutes, but remaining undetected in the Gamma Ray Bursts Monitor on BeppoSAX. They have properties very similar to the x-ray counterparts of GRBs and account for some of the Fast X-ray Transient events seen in almost every x-ray satellite. We review their X-ray properties and show that x-ray flashes are in fact very soft, x-ray rich, untriggered gamma ray bursts, in which the peak energy in 2-10 keV x-rays could be up to a factor of 100 larger than the peak energy in the 50-300 keV gamma ray range. The frequency is ? 100 yr ?1. 1 Fast X-ray Transients/High-latitude X-ray Transients Fast X-ray Transients have been observed with many x-ray satellites. In particular they are seen with x-ray instruments that scan the entire sky on a regular basis. Such events are detected in one sky scan and disappeared in the next, typically limiting the duration to be longer than a minute and shorter than a few hours. For this reason they are called Fast Transients. The first transients

John Heise; Jean In ’t Z; Peter M. Woods

2001-01-01T23:59:59.000Z

295

X-Ray Absorption and X-Ray Raman Scattering Studies of Battery ...  

Science Conference Proceedings (OSTI)

Knowledge of the redox chemistry and changes in the structure during electrochemical cycling is of paramount importance in designing new battery materials ...

296

Simulated X-Ray Absorption Spectroscopy on the Water Dimer  

DOE Green Energy (OSTI)

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

Wung, A

2004-02-05T23:59:59.000Z

297

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

DOE Green Energy (OSTI)

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

Guo, Jinghua

2008-09-22T23:59:59.000Z

298

Core and Valence Excitations in Resonant X-ray Spectroscopy using Restricted Excitation Window Time-dependent Density Functional Theory  

Science Conference Proceedings (OSTI)

We report simulations of X-ray absorption near edge structure (XANES), resonant inelastic X-ray scattering (RIXS) and 1D stimulated X-ray Raman spectroscopy (SXRS) signals of cysteine at the oxygen, nitrogen and sulfur K and L2,3 edges. The simulated XANES signals from the restricted window time-dependent density functional theory (REW-TDDFT) and the static exchange (STEX) method are compared with experiments, showing that REW-TDDFT is more accurate and computationally less expensive than STEX. Simulated RIXS and 1D SXRS signals from REW-TDDFT give some insights on the correlation of different excitations in the molecule.

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

2012-11-21T23:59:59.000Z

299

X-rays Illuminate Ancient Archimedes Text  

NLE Websites -- All DOE Office Websites (Extended Search)

Related Links: Related Links: May 2005 Headlines TIP Article Press Release Walters Art Museum SSRL Home Page SLAC Home Page Stanford Home Page Tuesday, 31 May 2005 X-rays Illuminate Ancient Archimedes Text (contact: Uwe Bergmann, bergmann@slac.stanford.edu) Archimedes Figure Image provided by Will Noel, The Walters Art Museum An early transcription of Archimedes' mathematical theories has been brought to light through the probing of high-intensity x-rays at SSRL's BL6-2. The text contains part of the Method of Mechanical Theorems, one of Archimedes' most important works, which was probably copied out by a scribe in the tenth century. The parchment on which it was written was later scraped down and reused as pages in a twelfth century prayer book, producing a document known as a palimpsest (which comes from the Greek,

300

High resolution x-ray microscope  

Science Conference Proceedings (OSTI)

The authors present x-ray images of grid meshes and biological material obtained using a microspot x-ray tube with a multilayer optic and a 92-element parabolic compound refractive lens (CRL) made of a plastic containing only hydrogen and carbon. Images obtained using this apparatus are compared with those using an area source with a spherical lens and a spherical lens with multilayer condenser. The authors found the best image quality using the multilayer condenser with a parabolic lens, compared to images with a spherical lens and without the multilayer optics. The resolution was measured using a 155-element parabolic CRL and a multilayer condenser with the microspot tube. The experiment demonstrates about 1.1 {mu}m resolution.

Gary, C. K.; Park, H.; Lombardo, L. W.; Piestrup, M. A.; Cremer, J. T.; Pantell, R. H.; Dudchik, Y. I. [Adelphi Technology, Inc. 981-B Industrial Road, San Carlos, California 94070 (United States); Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Institute of Applied Physics Problems, Kurchatova 7, Minsk 220064 (Belarus)

2007-04-30T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Sample holder for x-ray diffractometry  

DOE Patents (OSTI)

A sample holder for use with x-ray diffractometers with the capability to rotate the sample, as well as to adjust the position of the sample in the x, y, and z directions. Adjustment in the x direction is accomplished through loosening set screws, moving a platform, and retightening the set screws. Motion translators are used for adjustment in the y and z directions. An electric motor rotates the sample, and receives power from the diffractometer.

Hesch, V.L.

1991-12-31T23:59:59.000Z

302

Scattering Functions of Yolk-Shell Particles  

SciTech Connect

The single-particle small-angle scattering properties of the yolk-shell particle, a new type of core-shell particle with a mobile core within the hosting shell, are systematically investigated. The Debye spatial autocorrelation function, pair distance distribution function and intraparticle structure factor (form factor) are calculated and compared to the corresponding scattering functions of reference systems of hard sphere and concentric core-shell particles with identical sizes. Based on our theoretical calculations, we find that the broken centrosymmetry, originating from the mobility of the trapped yolk, results in an imaginary scattering amplitude. As a result, it contributes an additional destructive interference term which smears certain features present in the scattering functions of the reference systems. Based on our theoretical models, we present the prospect of jointly using small angle neutron and x-ray scattering techniques to quantitatively determine the structural characteristics of yolk-shell particles.

Li, Xin [ORNL] [ORNL; Liu, Kao-Hsiang [National Taiwan University] [National Taiwan University; Wu, Bin [ORNL] [ORNL; Sanchez-Diaz, Luis E [ORNL] [ORNL; Smith, Gregory Scott [ORNL] [ORNL; Chen, Wei-Ren [ORNL] [ORNL

2013-01-01T23:59:59.000Z

303

TENDER ENERGY X-RAY ABSORPTION  

NLE Websites -- All DOE Office Websites (Extended Search)

TENDER ENERGY X-RAY ABSORPTION TENDER ENERGY X-RAY ABSORPTION SPECTROSCOPY (TES) Project Team: S. Bare 1,2 , J. Brandes 3 , T. Buonassisi 4 , J. Chen 5,2 , M. Croft 6 , E. DiMasi 7 , A. Frenkel 8,2 , D. Hesterberg 9 , S. Hulbert 7,2 , S. Khalid 7 , S. Myneni 10 , P. Northrup 7,11 , E.T. Rasbury 11 , B. Ravel 12 , R. Reeder 11 , J. Rodriguez 7,2 , D. Sparks 5,13 , V. Stojanoff 7 , G. Waychunas 14 1 UOP LLC, 2 Synchrotron Catalysis Consortium, 3 Skidaway Inst. of Oceanography, 4 MIT Laboratory for Photovoltaics Research, 5 Univ. of Delaware, 6 Rutgers Univ., 7 Brookhaven National Lab, 8 Yeshiva Univ., 9 North Carolina State Univ., 10 Princeton Univ., 11 Stony Brook Univ., 12 NIST, 13 Delaware Environmental Inst., 14 Lawrence Berkeley National Lab TECHNIQUES: High performance and in-situ X-ray absorption spectroscopy and spatially-resolved XAS of

304

Hard X-ray Variability of AGN  

E-Print Network (OSTI)

Aims: Active Galactic Nuclei are known to be variable throughout the electromagnetic spectrum. An energy domain poorly studied in this respect is the hard X-ray range above 20 keV. Methods: The first 9 months of the Swift/BAT all-sky survey are used to study the 14 - 195 keV variability of the 44 brightest AGN. The sources have been selected due to their detection significance of >10 sigma. We tested the variability using a maximum likelihood estimator and by analysing the structure function. Results: Probing different time scales, it appears that the absorbed AGN are more variable than the unabsorbed ones. The same applies for the comparison of Seyfert 2 and Seyfert 1 objects. As expected the blazars show stronger variability. 15% of the non-blazar AGN show variability of >20% compared to the average flux on time scales of 20 days, and 30% show at least 10% flux variation. All the non-blazar AGN which show strong variability are low-luminosity objects with L(14-195 keV) < 1E44 erg/sec. Conclusions: Concerning the variability pattern, there is a tendency of unabsorbed or type 1 galaxies being less variable than the absorbed or type 2 objects at hardest X-rays. A more solid anti-correlation is found between variability and luminosity, which has been previously observed in soft X-rays, in the UV, and in the optical domain.

V. Beckmann; S. D. Barthelmy; T. J. -L. Courvoisier; N. Gehrels; S. Soldi; J. Tueller; G. Wendt

2007-09-14T23:59:59.000Z

305

Local structure of Rb{sub 2}Li{sub 4}(SeO{sub 4}){sub 3}{center_dot}2H{sub 2}O by the modeling of X-ray diffuse scattering - from average-structure to microdomain model  

Science Conference Proceedings (OSTI)

Local structure of dirubidium tetralithium tris(selenate(VI)) dihydrate - Rb{sub 2}Li{sub 4}(SeO{sub 4}){sub 3}{center_dot} 2H{sub 2}O has been determined basing on the modeling of X-ray diffuse scattering. The origin of observed structured diffuse streaks is SeO{sub 4} tetrahedra switching between two alternative positions in two quasi-planar layers existing in each unit cell and formation of domains with specific SeO{sub 4} tetrahedra configuration locally fulfilling condition for C-centering in the 2a Multiplication-Sign 2b Multiplication-Sign c superstructure cell. The local structure solution is characterized by a uniform distribution of rather large domains (ca. thousand of unit cells) in two layers, but also monodomains can be taken into account. Inside a single domain SeO{sub 4} tetrahedra are ordered along ab-diagonal forming two-string ribbons. Inside the ribbons SeO{sub 4} and LiO{sub 4} tetrahedra share the oxygen corners, whereas ribbons are bound to each other by a net of hydrogen bonds and fastened by corner sharing SeO{sub 4} tetrahedra of the neighboring layers. - Graphical abstract: Experimental sections of the reciprocal space showing diffraction effects observed for RLSO. Bragg spots are visible on sections with integer indices (1 kl section - on the left), streaks - on sections with fractional ones (1.5 kl section - on the right). At the center: resulting local structure of the A package modeled as a microdomain: two-string ribbons of ordered oxygen-corners-sharing SeO{sub 4} and LiO{sub 4} terahedra extended along ab-diagonal are seen; ribbons are bound by hydrogen bonds (shown in pink); the multiplied 2a Multiplication-Sign 2b unit cell is shown. Highlights: Black-Right-Pointing-Pointer X-ray diffuse scattering in RLSO was registered and modeled. Black-Right-Pointing-Pointer The origin of diffuse streaks is SeO{sub 4} tetrahedra switching in two structure layers. Black-Right-Pointing-Pointer The local structure is characterized by a uniform distribution of microdomains. Black-Right-Pointing-Pointer Inside a single domain SeO{sub 4} tetrahedra are ordered along ab-diagonal forming ribbons. Black-Right-Pointing-Pointer The ribbons are bound to each other by a net of hydrogen bonds.

Komornicka, Dorota [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okolna 2, 50-420 Wroclaw (Poland); Wolcyrz, Marek, E-mail: m.wolcyrz@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okolna 2, 50-420 Wroclaw (Poland); Pietraszko, Adam [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, ul. Okolna 2, 50-420 Wroclaw (Poland)

2012-08-15T23:59:59.000Z

306

Anomalous X-ray Diffraction Studies for Photovoltaic Applications  

DOE Green Energy (OSTI)

Anomalous X-ray Diffraction (AXRD) has become a useful technique in characterizing bulk and nanomaterials as it provides specific information about the crystal structure of materials. In this project we present the results of AXRD applied to materials for photovoltaic applications: ZnO loaded with Ga and ZnCo{sub 2}O{sub 4} spinel. The X-ray diffraction data collected for various energies were plotted in Origin software. The peaks were fitted using different functions including Pseudo Voigt, Gaussian, and Lorentzian. This fitting provided the integrated intensity data (peaks area values), which when plotted as a function of X-ray energies determined the material structure. For the first analyzed sample, Ga was not incorporated into the ZnO crystal structure. For the ZnCo{sub 2}O{sub 4} spinel Co was found in one or both tetrahedral and octahedral sites. The use of anomalous X-ray diffraction (AXRD) provides element and site specific information for the crystal structure of a material. This technique lets us correlate the structure to the electronic properties of the materials as it allows us to probe precise locations of cations in the spinel structure. What makes it possible is that in AXRD the diffraction pattern is measured at a number of energies near an X-ray absorption edge of an element of interest. The atomic scattering strength of an element varies near its absorption edge and hence the total intensity of the diffraction peak changes by changing the X-ray energy. Thus AXRD provides element specific structural information. This method can be applied to both crystalline and liquid materials. One of the advantages of AXRD in crystallography experiments is its sensitivity to neighboring elements in the periodic tables. This method is also sensitive to specific crystallographic phases and to a specific site in a phase. The main use of AXRD in this study is for transparent conductors (TCs) analysis. TCs are considered to be important materials because of their efficiency and low risk of environmental pollution. These materials are important to solar cells as a result of their remarkable combination of optical and electrical properties, including high electrical conductivity and high optical transparency in the spectrum of visible light. TCs provide a transparent window, which allows sunlight to pass through while also allowing electricity to conduct out of the cell. Spinel materials have the chemical form AB{sub 2}O{sub 4}, and are made of a face-centered cubic (FCC) lattice of oxygen anions and cations in specific interstitial sites. A normal spinel has all A cations on tetrahedral sites and B cations on octahedral sites. In contrast; an inverse spinel has the A and half of the B cations on octahedral sites and the other half of the B cations on tetrahedral sites; a mixed spinel lies between. In the spinel structure, 8 of 64 possible tetrahedral sites and 16 of 32 possible octahedral sites are filled. Normal spinels have particularly high conduction as the linear octahedral chains of B cations likely serve as conduction paths. In this paper we present how the data obtained with AXRD is used to analyze TCs properties as they apply to photovoltaic applications. One of the materials used for this analysis is zinc oxide. It has been loaded with 5% and 10% of Ga, which has an absorption edge of 10367 eV. The peak (100) was measured for the zinc oxide loaded with 10% Ga. In the case of 5% Ga, we measured peaks (100) and (101). With the information provided by the AXRD we can identify if Ga is being incorporated in the ZnO crystal structure. The analysis of 311 plane in the ZnCo{sub 2}O{sub 4} spinel shows if Co is in tetrahedral or octahedral site.

Not Available

2011-06-22T23:59:59.000Z

307

Energy Determination of X-Ray Transition Energies Using the ...  

Science Conference Proceedings (OSTI)

... We chose to measure x-ray transition energies from NIST ... This resulted in the production of x-ray emission ... would yield not only an energy scale for ...

2012-10-02T23:59:59.000Z

308

SLAC National Accelerator Laboratory - SLAC's X-ray Laser Explores...  

NLE Websites -- All DOE Office Websites (Extended Search)

X-ray Laser Explores Big Data Frontier By Glenn Roberts Jr. June 12, 2013 It's no surprise that the data systems for SLAC's Linac Coherent Light Source X-ray laser have drawn...

309

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Print Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in...

310

SLAC National Accelerator Laboratory - SLAC X-rays Help Discover...  

NLE Websites -- All DOE Office Websites (Extended Search)

which pulses 120 times a second. In the instant before the intense X-rays destroy a nanocrystal, detectors record a flash of X-ray diffraction information. Finally, scientists use...

311

Using Light to Control How X Rays Interact with Matter  

NLE Websites -- All DOE Office Websites (Extended Search)

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

312

Nuclear resonant X-ray spectroscopy of (Mg,Fe)SiO3 orthoenstatites JENNIFER M. JACKSON1,*, EMILY A. HAMECHER1  

E-Print Network (OSTI)

Nuclear resonant X-ray spectroscopy of (Mg,Fe)SiO3 orthoenstatites JENNIFER M. JACKSON1,*, EMILY A, 9700 S. Cass Ave., Argonne, IL 60439, USA Abstract: We present nuclear resonant inelastic X-ray scattering (NRIXS) and synchrotron Mo¨ssbauer spectroscopy (SMS) measurements, both nuclear resonant X

Jackson, Jennifer M.

313

Strengthened lithium for x-ray blast windows  

Science Conference Proceedings (OSTI)

Lithium's high x-ray transparency makes it an attractive material for windows intended to protect soft x-ray diagnostics in high energy density experiments. Pure lithium is soft and weak, but lithium mixed with lithium hydride powder becomes harder and stronger, in principle without any additional x-ray absorption. A comparison with the standard material for x-ray windows, beryllium, suggests that lithium or lithium strengthened by lithium hydride may well be an excellent option for such windows.

Pereira, N. R. [Ecopulse Inc., P.O. Box 528, Springfield, Virginia 22150 (United States); Imam, M. A. [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2008-05-15T23:59:59.000Z

314

Electron and X-Ray Microscopy: Structural Characterization of ...  

Science Conference Proceedings (OSTI)

Oct 28, 2009 ... Recent Advances in Structural Characterization of Materials: Electron and X-Ray Microscopy: Structural Characterization of Nanoscale ...

315

Design of a triaxial residual stress measurement system using high energy x-ray diffraction  

Science Conference Proceedings (OSTI)

Previous design studies in developing concepts for residual stress measurement in engineering materials have been extended. A pre-prototype energy dispersive x-ray diffraction (EDXRD) system has been fabricated. A 300 kV radiography source is used in conjunction with an intrinsic germanium detector and a MacII/LabVIEW data acquisition system. Specimens up to 25mm equivalent steel thickness (and one meter gross dimensions) can now be evaluated. The pre-prototype system serves as the hard x-ray, bulk stress measurement component of the previously reported hybrid stress measuring system (which would include a traditional multi-angle surface measurement system using soft x-rays). In addition, a detailed study of residual stress analytical equations has been completed and applied to various metallic and ceramic materials. During the grant period, related studies were completed on stress measurement using synchrotron radiation and on a critical review of the residual stress literature. 6 refs., 3 figs.

Shackelford, J.F.; Brown, B.D.; Park, J.S.

1989-01-01T23:59:59.000Z

316

Beamline and exposure station for deep x-ray lithography at the Advanced Photon Source  

Science Conference Proceedings (OSTI)

APS is a third-generation synchrotron radiation source. With an x-ray energy of 19.5 keV and highly collimated beam ( 1 mm) using deep x-ray lithography (DXRL). The 2-BM beamline was constructed and will be used for DXRL at APS. Selection of appropriate x-ray energy range is done through a variable-angle mirror and various filters in the beamline. At the exposure station, the beam size will be 100(H) x 5(V) mm{sup 2}. Uniform exposure will be achieved by a high-speed (100 mm/sec) vertical scanner, which allows precise angular ({approximately}0.1 mrad) and positional (conicals and other profiles. For 1-mm-thick PMMA, a 100 x 25 mm{sup 2} area can be fully exposed in about 1/2 hr, while even 10-mm-thick PMMA will require only 2-3 hours.

Lai, B.; Mancini, D.C.; Yun, W.; Gluskin, E.

1996-12-31T23:59:59.000Z

317

Phase Contrast Microscopy with Soft and Hard X-rays  

E-Print Network (OSTI)

Calibration ­ Uses up part of dynamic range · Solution: ­ Soft x-rays: Back side Illumination ­ Hard xPhase Contrast Microscopy with Soft and Hard X-rays Using a Segmented Detector Benjamin Hornberger ­ Phase Contrast 101 · A Segmented Detector for Hard X-ray Microprobes ­ Segmented Silicon Chip ­ Charge

Homes, Christopher C.

318

A bright point source of ultrashort hard x-rays from laser bioplasmas  

E-Print Network (OSTI)

Micro and nano structures scatter light and amplify local electric fields very effectively. Energy incident as intense ultrashort laser pulses can be converted to x-rays and hot electrons more efficiently with a substrate that suitably modifies the local fields. Here we demonstrate that coating a plain glass surface with a few micron thick layer of an ubiquitous microbe, {\\it Escherichia coli}, catapults the brightness of hard x-ray bremsstrahlung emission (up to 300 keV) by more than two orders of magnitude at an incident laser intensity of 10$^{16}$ W cm$^{-2}$. This increased yield is attributed to the local enhancement of electric fields around individual {\\it E. coli} cells and is reproduced by detailed particle-in-cell (PIC) simulations. This combination of laser plasmas and biological targets can lead to turnkey, multi-kilohertz and environmentally safe sources of hard x-rays.

Krishnamurthy, M; Lad, Amit D; Ahmad, Saima; Narayanan, V; Rajeev, R; Kundu, M; Kumar, G Ravindra; Ray, Krishanu

2010-01-01T23:59:59.000Z

319

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

DOE Green Energy (OSTI)

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

Friebel, Daniel

2011-08-24T23:59:59.000Z

320

Advanced Research in Diesel Fuel Sprays Using X-rays From The Advanced Photon Source  

DOE Green Energy (OSTI)

The fuel distribution and degree of atomization in the combustion chamber is a primary factor in the formation of emissions in diesel engines. A number of diagnostics to study sprays have been developed over the last twenty years; these are primarily based on visible light measurement techniques. However, visible light scatters strongly from fuel droplets surrounding the spray, which prevents penetration of the light. This has made quantitative measurements of the spray core very difficult, particularly in the relatively dense near- nozzle region [1-3]. For this reason we developed the x-ray technique to study the properties of fuel sprays in a quantitative way [4]. The x-ray technique is not limited by scattering, which allows it to be used to make quantitative measurements of the fuel distribution. These measurements are particularly effective in the region near the nozzle where other techniques fail. This technique has led to a number of new insights into the structure of fuel sprays, including the discovery and quantitative measurement of shock waves generated under some conditions by high-pressure diesel sprays [5]. We also performed the first-ever quantitative measurements of the time-resolved mass distribution in the near-nozzle region, which demonstrated that the spray is atomized only a few nozzle diameters from the orifice [6]. Our recent work has focused on efforts to make measurements under pressurized ambient conditions. We have recently completed a series of measurements at pressures up to 5 bar and are looking at the effect of ambient pressure on the structure of the spray. The enclosed figure shows the mass distributions measured for 1,2, and 5 bar ambient pressures. As expected, the penetration decreases as the pressure increases. This leads to changes in the measured mass distribution, including an increase in the density at the leading edge of the spray. We have also observed a narrowing in the cone angle of the spray core as the pressure increases. This is counter to visible light spray measurements, and current work is underway in an effort to understand this effect.

Powell, C

2003-08-24T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

X-Ray Shines Light on Water Mystery  

DOE Green Energy (OSTI)

Water is the key compound for our existence on this planet and it is involved in many important physical, chemical, biological and geological processes. Although water is the most common molecular substance it is also most unusual with many anomalies in its thermodynamic properties such as compressibility, density variation and heat capacity. The question of the structure of the hydrogen bonding network in water has been discussed intensively for over 100 years and has not yet been resolved. This talk will describe recent x-ray spectroscopy and scattering measurements showing that the liquid can be described as fluctuations between two types of local hydrogen bonded structures driven by in commensurate requirements for minimizing enthalpy and maximizing entropy.

Nilsson, Anders (SLAC)

2010-11-17T23:59:59.000Z

322

Quantitative Analysis of Mt. St. Helens Ash by X-Ray Diffraction and X-Ray Fluorescence Spectrometry  

Science Conference Proceedings (OSTI)

A quantitative study by x-ray diffraction, optical polarizing microscopy, and x-ray fluorescence spectrometry of fallout and ambient ash from three Mt. St. Helens eruptions has revealed a consistent picture of the mineralogical and elemental ...

Briant L. Davis; L. Ronald Johnson; Dana T. Griffen; William Revell Phillips; Robert K. Stevens; David Maughan

1981-08-01T23:59:59.000Z

323

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

DOE Patents (OSTI)

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

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

1999-05-01T23:59:59.000Z

324

Calibrating X-ray Imaging Devices for Accurate Intensity Measurement  

SciTech Connect

The purpose of the project presented is to develop methods to accurately calibrate X-ray imaging devices. The approach was to develop X-ray source systems suitable for this endeavor and to develop methods to calibrate solid state detectors to measure source intensity. NSTec X-ray sources used for the absolute calibration of cameras are described, as well as the method of calibrating the source by calibrating the detectors. The work resulted in calibration measurements for several types of X-ray cameras. X-ray camera calibration measured efficiency and efficiency variation over the CCD. Camera types calibrated include: CCD, CID, back thinned (back illuminated), front illuminated.

Haugh, M. J.

2011-07-28T23:59:59.000Z

325

Deducing the Orientation of the Semimajor Axis of the Eta Carinae Binary System from X-ray Observations  

E-Print Network (OSTI)

We study the usage of the X-ray light curve, column density toward the hard X-ray source, and emission measure (density square times volume), of the massive binary system Eta Carinae to determine the orientation of its semi-major axis. The source of the hard X-ray emission is the shocked secondary wind. We argue that, by itself, the observed X-ray flux cannot teach us much about the orientation of the semi-major axis. Minor adjustment of some unknown parameters of the binary system allows to fit theX-ray light curve with almost any inclination angle and orientation. The column density and X-ray emission measure, on the other hand, impose strong constrains on the orientation. We improve our previous calculations and show that the column density is more compatible with an orientation where for most of the time the secondary - the hotter, less massive star - is behind the primary star. The secondary comes closer to the observer only for a short time near periastron passage. The ten-week X-ray deep minimum, which...

Soker, Amit Kashi Noam

2009-01-01T23:59:59.000Z

326

Apparatus for monitoring x-ray beam alignment  

DOE Patents (OSTI)

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

Steinmeyer, P.A.

1989-09-12T23:59:59.000Z

327

[Research at and operation of the material science x-ray absorption beamline (X-11) at the National Synchrotron Light Source]. Progress report  

Science Conference Proceedings (OSTI)

This report discusses three projects at the Material Science X-Ray Absorption Beamline. Topics discussed include: XAFS study of some titanium silicon and germanium compounds; initial XAS results of zirconium/silicon reactions; and low angle electron yield detector.

Not Available

1992-08-01T23:59:59.000Z

328

(Research at and operation of the material science x-ray absorption beamline (X-11) at the National Synchrotron Light Source)  

Science Conference Proceedings (OSTI)

This report discusses three projects at the Material Science X-Ray Absorption Beamline. Topics discussed include: XAFS study of some titanium silicon and germanium compounds; initial XAS results of zirconium/silicon reactions; and low angle electron yield detector.

Not Available

1992-01-01T23:59:59.000Z

329

Photon Sciences | Beamlines | HXN: Hard X-ray Nanoprobe  

NLE Websites -- All DOE Office Websites (Extended Search)

HXN: Hard X-ray Nanoprobe HXN: Hard X-ray Nanoprobe Poster | Fact Sheet | Preliminary Design Report Scientific Scope The Hard X-ray Nanoprobe beamline and endstation instruments (HXN) will be designed and constructed to explore new frontiers of hard x-ray microscopy applications with the highest achievable spatial resolution. Currently the available spatial resolution for scientific applications, provided by scanning x-ray microscopes in the hard x-ray regime, is limited to ~50nm, which is still insufficient for probing the nanoscale interfacial structures critical in determining properties and functionalities of material and biological systems. The HXN beamline aims to enable x-ray experiments at spatial resolutions ranging from 10 to 30 nm with an ultimate goal of ~1 nm. Beamline Description

330

Virtual Compton scattering and neutral pion electroproduction in the resonance region up to the deep inelastic region at backward angles  

Science Conference Proceedings (OSTI)

We have made the first measurements of the virtual Compton scattering (VCS) process via the H(e,e'p)? exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the W-dependence at fixed Q2=1 GeV2, and for the Q2-dependence at fixed W near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed Q2-dependence is smooth. The measured ratio of H(e,e'p)? to H(e,e'p)?0 cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to Real Compton Scattering (RCS) at high energy and large angles, our VCS data at the highest W (1.8-1.9 GeV) show a striking Q2-independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.

Laveissiere, Geraud; Degrande, Natalie; Jaminion, Stephanie; Jutier, Christophe; Todor, Luminita; Di Salvo, Rachele; Van Hoorebeke, L.; Alexa, L.C.; Anderson, Brian; Aniol, Konrad; Arundell, Kathleen; Audit, Gerard; Auerbach, Leonard; Baker, F.; Baylac, Maud; Berthot, J.; Bertin, Pierre; Bertozzi, William; Bimbot, Louis; Boeglin, Werner; Brash, Edward; Breton, Vincent; Breuer, Herbert; Burtin, Etienne; Calarco, John; Cardman, Lawrence; Cavata, Christian; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chang, C.; Chang, C.C.; Chen, Jian-Ping; Chudakov, Eugene; Cisbani, Evaristo; Dale, Daniel; De Jager, Cornelis; De Leo, Raffaele; Deur, Alexandre; D'Hose, Nicole; Dodge, Gail; Domingo, John; Elouadrhiri, Latifa; Epstein, Martin; Ewell, Lars; Finn, John; Fissum, Kevin; Fonvieille, Helene; Fournier, Guy; Frois, Bernard; Frullani, Salvatore; Furget, Christophe; Gao, Haiyan; Gao, Juncai; Garibaldi, Franco; Gasparian, Ashot; Gilad, Shalev; Gilman, Ronald; Glamazdin, Oleksandr; Glashausser, Charles; Gomez, Javier; Gorbenko, Viktor; Grenier, Philippe; Guichon, Pierre; Hansen, Jens-Ole; Holmes, Richard; Holtrop, Maurik; Howell, Calvin; Huber, Garth; Hyde, Charles; Incerti, Sebastien; Iodice, Mauro; Jardillier, Johann; Jones, Mark; Kahl, William; Kamalov, Sabit; Kato, Seigo; Katramatou, A.T.; Kelly, James; Kerhoas, Sophie; Ketikyan, Armen; Khayat, Mohammad; Kino, Kouichi; Kox, Serge; Kramer, Laird; Kumar, Krishna; Kumbartzki, Gerfried; Kuss, Michael; Leone, Antonio; LeRose, John; Liang, Meihua; Lindgren, Richard; Liyanage, Nilanga; Lolos, George; Lourie, Robert; Madey, Richard; Maeda, Kazushige; Malov, Sergey; Manley, D.; Marchand, Claude; Marchand, Dominique; Margaziotis, Demetrius; Markowitz, Pete; Marroncle, Jacques; Martino, Jacques; McCormick, Kathy; McIntyre, Justin; Mehrabyan, Surik; Merchez, Fernand; Meziani, Zein-Eddine; Michaels, Robert; Miller, Gerald; Mougey, Jean; Nanda, Sirish; Neyret, Damien; Offermann, Edmond; Papandreou, Zisis; Perdrisat, Charles; Perrino, R.; Petratos, Gerassimos; Platchkov, Stephane; Pomatsalyuk, Roman; Prout, David; Punjabi, Vina; Pussieux, Thierry; Quemener, Gilles; Ransome, Ronald; Ravel, Oliver; Real, Jean-Sebastien; Renard, F.; Roblin, Yves; Rowntree, David; Rutledge, Gary; Rutt, Paul; Saha, Arunava; Saito, Teijiro; Sarty, Adam; Serdarevic, A.; Smith, T.; Smirnov, G.; Soldi, K.; Sorokin, Pavel; Souder, Paul; Suleiman, Riad; Templon, Jeffrey; Terasawa, Tatsuo; Tiator, Lothar; Tieulent, Raphael; Tomasi-Gustaffson, E.; Tsubota, Hiroaki; Ueno, Hiroaki; Ulmer, Paul; Urciuoli, Guido; Van De Vyver, R.; van der Meer, Rob; Vernin, Pascal; Vlahovic, B.; Voskanyan, Hakob; Voutier, Eric; Watson, J.W.; Weinstein, Lawrence; Wijesooriya, Krishni; Wilson, R.; Wojtsekhowski, Bogdan; Zainea, Dan; Zhang, Wei-Ming; Zhao, Jie; Zhou, Z.-L.

2009-01-01T23:59:59.000Z

331

Virtual Compton scattering and neutral pion electroproduction in the resonance region up to the deep inelastic region at backward angles  

Science Conference Proceedings (OSTI)

We have made the first measurements of the virtual Compton scattering (VCS) process via the H(e, e{sup '}p){gamma} exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the W-dependence at fixed Q{sup 2}=1 GeV{sup 2} and for the Q{sup 2} dependence at fixed W near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed Q{sup 2} dependence is smooth. The measured ratio of H(e, e{sup '}p){gamma} to H(e, e{sup '}p){pi}{sup 0} cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to real Compton scattering (RCS) at high energy and large angles, our VCS data at the highest W (1.8-1.9 GeV) show a striking Q{sup 2} independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.

Laveissiere, G.; Jaminion, S.; Salvo, R. Di; Berthot, J.; Bertin, P. Y.; Breton, V.; Fonvieille, H.; Grenier, P.; Ravel, O.; Roblin, Y.; Smirnov, G. [LPC-Clermont, Universite Blaise Pascal, CNRS/IN2P3, F-63177 Aubiere Cedex (France); Degrande, N.; Hoorebeke, L. van; Vyver, R. van de [University of Gent, B-9000 Gent (Belgium); Jutier, C.; Hyde, C. E. [LPC-Clermont, Universite Blaise Pascal, CNRS/IN2P3, F-63177 Aubiere Cedex (France); Old Dominion University, Norfolk, Virginia 23529 (United States); Todor, L.; Dodge, G. E.; McCormick, K.; Ulmer, P. E. [Old Dominion University, Norfolk, Virginia 23529 (United States)] (and others)

2009-01-15T23:59:59.000Z

332

X-ray chemistry in envelopes around young stellar objects  

E-Print Network (OSTI)

We present chemical models of the envelope of a young stellar object (YSO) exposed to a central X-ray source. The models are applied to the massive star-forming region AFGL 2591 for different X-ray fluxes. The total X-ray ionization rate is dominated by the `secondary' ionization rate of H2 resulting from fast electrons. The carbon, sulphur and nitrogen chemistries are discussed. It is found that He+ and H3+ are enhanced and trigger a peculiar chemistry. Several molecular X-ray tracers are found and compared to tracers of the far ultraviolet (FUV) field. Like ultraviolet radiation fields, X-rays enhance simple hydrides, ions and radicals. In contrast to ultraviolet photons, X-rays can penetrate deep into the envelope and affect the chemistry even at large distances from the source. Whereas the FUV enhanced species cover a region of 200-300 AU, the region enhanced by X-rays is >1000 AU. Best-fit models for AFGL 2591 predict an X-ray luminosity LX > 1e+31 ergs/s with a hard X-ray spectrum TX > 3e+07 K. Furthermore, we find LX/Lbol ~ 1e-6. The chemistry of the bulk of the envelope mass is dominated by cosmic-ray induced reactions rather than by X-ray induced ionization for X-ray luminosities LX < 1e+33 ergs/s. The calculated line intensities of HCO+ and HCS+ show that high-J lines are more affected than lower J lines by the presence of X-rays due to their higher critical densities, and that such differences are detectable even with large aperture single-dish telescopes. Future instruments such as Herschel-HIFI or SOFIA will be able to observe X-ray enhanced hydrides whereas the sensitivity and spatial resolution of ALMA is well-suited to measure the size and geometry of the region affected by X-rays.

P. Staeuber; S. D. Doty; E. F. van Dishoeck; A. O. Benz

2005-06-14T23:59:59.000Z

333

ASCA Observation of an X-Ray-Luminous Active Nucleus in Markarian 231  

E-Print Network (OSTI)

We have obtained a moderately long (100 kilosecond) ASCA observation of the Seyfert 1 galaxy Markarian 231, the most luminous of the local ultraluminous infrared galaxy (ULIRG) population. In the best-fitting model we do not see the X-ray source directly; the spectrum consists of a scattered power-law component and a reflection component, both of which have been absorbed by a column N_H \\approx 3 X 10^(22)/cm^2. About 3/4 of the observed hard X-rays arise from the scattered component, reducing the equivalent width of the iron K alpha line. The implied ratio of 1-10 keV X-ray luminosity to bolometric luminosity, L_x/L_bol \\sim 2%, is typical of Sy 1 galaxies and radio-quiet QSOs of comparable bolometric luminosities, and indicates that the bolometric luminosity is dominated by the AGN. Our estimate of the X-ray luminosity also moves Mrk 231 in line with the correlations found for AGN with extremely strong Fe II emission. A second source separated by about 2 arcminutes is also clearly detected, and contributes ...

Maloney, P R; Maloney, Philip R.; Reynolds, Christopher S

2000-01-01T23:59:59.000Z

334

X-Ray Diffraction on NIF  

SciTech Connect

The National Ignition Facility (NIF) is currently a 192 beam, 1.6 MJ laser. NIF Ramp-Compression Experiments have already made the relevant exo-planet pressure range from 1 to 50 Mbar accessible. We Proposed to Study Carbon Phases by X-Ray Diffraction on NIF. Just a few years ago, ultra-high pressure phase diagrams for materials were very 'simple'. New experiments and theories point out surprising and decidedly complex behavior at the highest pressures considered. High pressures phases of aluminum are also predicted to be complex. Recent metadynamics survey of carbon proposed a dynamic pathway among multiple phases. We need to develop diagnostics and techniques to explore this new regime of highly compressed matter science. X-Ray Diffraction - Understand the phase diagram/EOS/strength/texture of materials to 10's of Mbar. Strategy and physics goals: (1) Powder diffraction; (2) Begin with diamond; (3) Continue with metals etc.; (4) Explore phase diagrams; (5) Develop liquid diffraction; and (6) Reduce background/improve resolution.

Eggert, J H; Wark, J

2012-02-15T23:59:59.000Z

335

Proton induced quasi-monochromatic x-ray beams for soft x-ray spectroscopy studies and selective x-ray fluorescence analysis  

Science Conference Proceedings (OSTI)

We present the analytical features and performance of an x-ray spectroscopy end station of moderate energy resolution operating with proton-induced quasi-monochromatic x-ray beams. The apparatus was designed, installed and operated at the 5.5 MV Tandem VdG Accelerator Laboratory of the Institute of Nuclear Physics, N.C.S.R. 'Demokritos,' Athens. The setup includes a two-level ultrahigh vacuum chamber that hosts in the lower level up to six primary targets in a rotatable holder; there, the irradiation of pure element materials-used as primary targets-with few-MeV high current ({approx}{mu}A) proton beams produces intense quasi-monochromatic x-ray beams of selectable energy. In the chamber's upper level, a six-position rotatable sample holder hosts the targets considered for x-ray spectroscopy studies. The proton-induced x-ray beam, after proper collimation, is guided to the sample position whereas various filters can be also inserted along the beam's path to eliminate the backscattered protons or/and to absorb selectively components of the x-ray beam. The apparatus incorporates an ultrathin window Si(Li) spectrometer (FWHM 136 eV at 5.89 keV) coupled with low-noise electronics capable of efficiently detecting photons down to carbon K{alpha}. Exemplary soft x-ray spectroscopy studies and results of selective x-ray fluorescence analysis are presented.

Sokaras, D. [Institute of Nuclear Physics, N.C.S.R. Demokritos, Aghia Paraskevi, 15310 Athens (Greece); Zarkadas, Ch. [PANalytical B.V., 7600 AA Almelo (Netherlands); Fliegauf, R.; Beckhoff, B. [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany); Karydas, A. G. [Institute of Nuclear Physics, N.C.S.R. Demokritos, Aghia Paraskevi, 15310 Athens (Greece); Nuclear Spectrometry and Applications Laboratory, IAEA Laboratories, A-2444 Seibersdorf (Austria)

2012-12-15T23:59:59.000Z

336

A Liquid Hydrogen Target for Precision Measurement of the Weak Mixing Angle in Moller Scattering at SLAC  

DOE Green Energy (OSTI)

A 150 cm long liquid hydrogen target has been built for the SLAC End Station A E158 experiment. The target loop volume is 55 liters, and the maximum target heat load deposited by the electron beam is {approx} 700 W. The liquid hydrogen density fluctuation with full beam current (120 Hz repetition rate, 6 x 10{sup 11} electrons/spill) on target is well below 10{sup -4} level, which fulfills the requirement for a precision measurement of the weak mixing angle in the polarized electron-electron scattering process.

Weisend, John G

2002-11-07T23:59:59.000Z

337

2011 X-Ray Science Gordon Research Conference (August 7-12, 2011, Colby, College. Waterville, ME)  

SciTech Connect

The 2011 Gordon Research Conference on X-ray Science will feature forefront x-ray-based science enabled by the rapid improvements in synchrotron and x-ray laser sources. Across the world, x-ray sources are playing an increasingly important role in physics, materials, chemistry, and biology, expanding into ever broadening areas of science and engineering. With the first hard x-ray free electron laser source beginning operation and with other advanced x-ray sources operational and planned, it is a very exciting and pivotal time for exchange ideas about the future of x-ray science and applications. The Conference will provide the forum for this interaction. An international cast of speakers will illuminate sessions on ultrafast science, coherence, imaging, in situ studies, extreme conditions, new developments in optics, sources, and detectors, inelastic scattering, nanoscience, life science, and energy sciences. The Conference will bring together investigators at the forefront of these areas, and will provide a venue for young scientists entering a career in x-ray research to present their research in poster format, hold discussions in a friendly setting, and exchange ideas with leaders in the field. Some poster presenters will be selected for short talks. The collegial atmosphere of this Conference, with ample time for discussion as well as opportunities for informal gatherings in the afternoons and evenings, will provide an avenue for scientists from different disciplines to exchange ideas about forefront x-ray techniques and will promote cross-fertilization between the various research areas represented.

Gregory Stephenson

2011-08-12T23:59:59.000Z

338

Absolute x-ray energy calibration over a wide energy range using a diffraction-based iterative method  

SciTech Connect

In this paper, we report a method of precise and fast absolute x-ray energy calibration over a wide energy range using an iterative x-ray diffraction based method. Although accurate x-ray energy calibration is indispensable for x-ray energy-sensitive scattering and diffraction experiments, there is still a lack of effective methods to precisely calibrate energy over a wide range, especially when normal transmission monitoring is not an option and complicated micro-focusing optics are fixed in place. It is found that by using an iterative algorithm the x-ray energy is only tied to the relative offset of sample-to-detector distance, which can be readily varied with high precision of the order of 10{sup -5}-10{sup -6} spatial resolution using gauge blocks. Even starting with arbitrary initial values of 0.1 A, 0.3 A, and 0.4 A, the iteration process converges to a value within 3.5 eV for 31.122 keV x-rays after three iterations. Different common diffraction standards CeO{sub 2}, Au, and Si show an energy deviation of 14 eV. As an application, the proposed method has been applied to determine the energy-sensitive first sharp diffraction peak of network forming GeO{sub 2} glass at high pressure, exhibiting a distinct behavior in the pressure range of 2-4 GPa. Another application presented is pair distribution function measurement using calibrated high-energy x-rays at 82.273 keV. Unlike the traditional x-ray absorption-based calibration method, the proposed approach does not rely on any edges of specific elements, and is applicable to the hard x-ray region where no appropriate absorption edge is available.

Hong Xinguo; Chen Zhiqiang [Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794 (United States); Duffy, Thomas S. [Department of Geosciences, Princeton University, Princeton, New Jersey 08544 (United States)

2012-06-15T23:59:59.000Z

339

The Supergiant Fast X-ray Transient with the shortest orbital period: Suzaku observes one orbit in IGRJ16479-4514  

E-Print Network (OSTI)

The eclipsing hard X-ray source IGR J16479-4514 is the Supergiant Fast X-ray Transient (SFXT) with the shortest orbital period (3.32 days). This allowed us to perform a 250 ks long X-ray observation with Suzaku in 2012 February, covering most of its orbit, including the eclipse egress. Outside the eclipse, the source luminosity is around a few 1E34erg/s. The X-ray spectrum can be fit with an absorbed power law together with a neutral iron emission line at 6.4 keV. The column density is constant at 1E23 cm-2 outside the X-ray eclipse. During the eclipse it is lower, consistent with a scattering origin for the low X-ray emission during the eclipse by the supergiant companion wind. The scattered X-ray emission during the X-ray eclipse is used to directly probe the density of the companion wind at the orbital separation, resulting in 7E-14 g/cm3, which translates into a ratio Mdot_w/v_terminal = 7E-17 solar masses/km of the wind mass loss rate to the wind terminal velocity. This ratio, assuming reasonable termina...

Sidoli, L; Sguera, V; Bodaghee, A; Tomsick, J A; Pottschmidt, K; Rodriguez, J; Romano, P; Wilms, J

2013-01-01T23:59:59.000Z

340

Gray scale x-ray mask  

DOE Patents (OSTI)

The present invention describes a method for fabricating an embossing tool or an x-ray mask tool, providing microstructures that smoothly vary in height from point-to-point in etched substrates, i.e., structure which can vary in all three dimensions. The process uses a lithographic technique to transfer an image pattern in the surface of a silicon wafer by exposing and developing the resist and then etching the silicon substrate. Importantly, the photoresist is variably exposed so that when developed some of the resist layer remains. The remaining undeveloped resist acts as an etchant barrier to the reactive plasma used to etch the silicon substrate and therefore provides the ability etch structures of variable depths.

Morales, Alfredo M. (Livermore, CA); Gonzales, Marcela (Seattle, WA)

2006-03-07T23:59:59.000Z

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341

Extending synchrotron-based atomic physics experiments into the hard X-ray region  

Science Conference Proceedings (OSTI)

The high-brightness, hard x-ray beams available from third-generation synchrotron sources are opening new opportunities to study the deepest inner shells of atoms, an area where little work has been done and phenomena not observed in less tightly bound inner-shells are manifested. In addition scattering processes which are weak at lower energies become important, providing another tool to investigate atomic structure as well as an opportunity to study photon/atom interactions beyond photoabsorption. In this contribution the authors discuss some of the issues related to extending synchrotron-based atomic physics experiments into the hard x-ray region from the physical and the experimental point of view. They close with a discussion of a technique, resonant Raman scattering, that may prove invaluable in determining the spectra of the very highly-excited states resulting from the excitation of deep inner shells.

LeBrun, T. [Argonne National Lab., IL (United States). Physics Div.

1996-12-31T23:59:59.000Z

342

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Print Biological Imaging by Soft X-Ray Diffraction Microscopy Print Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in their ability to image with nanometer-scale resolution in three dimensions nonperiodic objects that are several microns in size. To fill this gap, the technique of coherent x-ray diffraction imaging now under development takes advantage of the penetrating power of x rays while simultaneously removing the limitations imposed by lens-based optical systems. Researchers from Stony Brook University, in collaboration with scientists at the ALS and Cornell University, have taken a large step in this direction by using a lensless x-ray diffraction microscope to image a freeze-dried yeast cell to better than 30-nm resolution. Images were made at several angular orientations of the cell.

343

Definition: X-Ray Diffraction (XRD) | Open Energy Information  

Open Energy Info (EERE)

X-Ray Diffraction (XRD) X-Ray Diffraction (XRD) Jump to: navigation, search Dictionary.png X-Ray Diffraction (XRD) X-Ray Diffraction (XRD) is a laboratory-based technique commonly used for identification of crystalline materials and analysis of unit cell dimensions. One of two primary types of XRD analysis (X-ray powder diffraction and single-crystal XRD) is commonly applied to samples to obtain specific information about the crystalline material under investigation. X-ray powder diffraction is widely used in geology, environmental science, material science, and engineering to rapidly identify unknown crystalline substances (typically in less than 20 minutes). A pure, finely ground, and homogenized sample is required for determination of the bulk composition. Additional uses include detailed

344

X-Ray Diffraction (XRD) | Open Energy Information  

Open Energy Info (EERE)

X-Ray Diffraction (XRD) X-Ray Diffraction (XRD) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: X-Ray Diffraction (XRD) Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Rock Lab Analysis Information Provided by Technique Lithology: Rapid and unambiguous identification of unknown minerals.[1] Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png X-Ray Diffraction (XRD): X-Ray Diffraction (XRD) is a laboratory-based technique commonly used for identification of crystalline materials and analysis of unit cell dimensions. One of two primary types of XRD analysis (X-ray powder diffraction and single-crystal XRD) is commonly applied to samples to

345

Portable X-Ray Diffraction (XRD) | Open Energy Information  

Open Energy Info (EERE)

Portable X-Ray Diffraction (XRD) Portable X-Ray Diffraction (XRD) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Portable X-Ray Diffraction (XRD) Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Data Collection and Mapping Parent Exploration Technique: Data Collection and Mapping Information Provided by Technique Lithology: Rapid and unambiguous identification of unknown minerals.[1] Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Portable X-Ray Diffraction (XRD): Portable X-Ray Diffraction (XRD) is a field-based technique that can be used for identification of crystalline materials and analysis of unit cell dimensions. Portable XRD analysis is similar to X-ray powder diffraction,

346

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Print Biological Imaging by Soft X-Ray Diffraction Microscopy Print Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in their ability to image with nanometer-scale resolution in three dimensions nonperiodic objects that are several microns in size. To fill this gap, the technique of coherent x-ray diffraction imaging now under development takes advantage of the penetrating power of x rays while simultaneously removing the limitations imposed by lens-based optical systems. Researchers from Stony Brook University, in collaboration with scientists at the ALS and Cornell University, have taken a large step in this direction by using a lensless x-ray diffraction microscope to image a freeze-dried yeast cell to better than 30-nm resolution. Images were made at several angular orientations of the cell.

347

X-Ray Fluorescence (XRF) | Open Energy Information  

Open Energy Info (EERE)

X-Ray Fluorescence (XRF) X-Ray Fluorescence (XRF) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: X-Ray Fluorescence (XRF) Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Rock Lab Analysis Information Provided by Technique Lithology: Bulk and trace element analysis of rocks, minerals, and sediments. Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png X-Ray Fluorescence (XRF): X-Ray Fluorescence is a lab-based technique used for bulk chemical analysis of rock, mineral, sediment, and fluid samples. The technique depends on the fundamental principles of x-ray interactions with solid materials, similar

348

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Print Biological Imaging by Soft X-Ray Diffraction Microscopy Print Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in their ability to image with nanometer-scale resolution in three dimensions nonperiodic objects that are several microns in size. To fill this gap, the technique of coherent x-ray diffraction imaging now under development takes advantage of the penetrating power of x rays while simultaneously removing the limitations imposed by lens-based optical systems. Researchers from Stony Brook University, in collaboration with scientists at the ALS and Cornell University, have taken a large step in this direction by using a lensless x-ray diffraction microscope to image a freeze-dried yeast cell to better than 30-nm resolution. Images were made at several angular orientations of the cell.

349

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Biological Imaging by Soft X-Ray Diffraction Microscopy Print Biological Imaging by Soft X-Ray Diffraction Microscopy Print Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in their ability to image with nanometer-scale resolution in three dimensions nonperiodic objects that are several microns in size. To fill this gap, the technique of coherent x-ray diffraction imaging now under development takes advantage of the penetrating power of x rays while simultaneously removing the limitations imposed by lens-based optical systems. Researchers from Stony Brook University, in collaboration with scientists at the ALS and Cornell University, have taken a large step in this direction by using a lensless x-ray diffraction microscope to image a freeze-dried yeast cell to better than 30-nm resolution. Images were made at several angular orientations of the cell.

350

Density gradient free electron collisionally excited x-ray laser  

DOE Patents (OSTI)

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

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

1984-11-29T23:59:59.000Z

351

Fabrication process for a gradient index x-ray lens  

DOE Patents (OSTI)

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

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

1995-01-01T23:59:59.000Z

352

Fabrication process for a gradient index x-ray lens  

DOE Patents (OSTI)

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

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

1995-01-17T23:59:59.000Z

353

Multilayers for next generation x-ray sources  

Science Conference Proceedings (OSTI)

Multilayers are artificially layered structures that can be used to create optics and optical elements for a broad range of x-ray wavelengths, or can be optimized for other applications. The development of next generation x-ray sources (synchrotrons and x-ray free electron lasers) requires advances in x-ray optics. Newly developed multilayer-based mirrors and optical elements enabled efficient band-pass filtering, focusing and time resolved measurements in recent FLASH (Free Electron LASer in Hamburg) experiments. These experiments are providing invaluable feedback on the response of the multilayer structures to high intensity, short pulsed x-ray sources. This information is crucial to design optics for future x-ray free electron lasers and to benchmark computer codes that simulate damage processes.

Bajt, S; Chapman, H N; Spiller, E; Hau-Riege, S; Alameda, J; Nelson, A J; Walton, C C; Kjornrattanawanich, B; Aquila, A; Dollar, F; Gullikson, E; Tarrio, C

2007-05-04T23:59:59.000Z

354

Rigorous Simulation of X-Ray Thermal Diffuse Scattering  

Science Conference Proceedings (OSTI)

In-Situ Neutron Diffraction and Crystal Plasticity Modeling of a-Uranium · In-Situ Studies of the ... Thermal Residual Stresses and Strains in Depleted Uranium.

355

X-ray Diffuse Scattering Measurements of Nucleation Dynamics...  

NLE Websites -- All DOE Office Websites (Extended Search)

high pressure conditions which relax into the liquid-vapor coexistence region of the phase diagram, leading to a rapid phase-explosion-driven boiling process within the...

356

NIST X-Ray Form Factor, Atten., and Scattering Database  

Science Conference Proceedings (OSTI)

... regard to extrapolation to energies outside tabulated ... K , as functions of energy and wavelength ... and by NIST's Systems Integration for Manufacturing ...

2011-12-09T23:59:59.000Z

357

National School on Neutron and X-ray Scattering  

NLE Websites -- All DOE Office Websites (Extended Search)

B See "Experiments Schedule" Experiment Time C See "Experiments Schedule" ReceptionBanquet Argonne Guest House Building 460 6:00 pm - Reception 7:00 pm - Dinner 7:00 pm Dinner...

358

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

Symposium on Optics and Photonics, San Diego, California, July 31-August 4, 2005. Proc. SPIE, Vol. 5932, 59322A, Sept. 19, 2005. Turgeman, R., Gershevitz, O., Deutsch, M., Ocko,...

359

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

S.-W. Magnetic-field-induced collapse of charge-ordered nanoclusters and the colossal magnetoresistance effect in Nd0.7Sr0.3MnO3. Phys. Rev. B 64, 220405(R), 1-5 (2001)....

360

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

G., Balicas, L., Xin, Y., Dagotto, E., Crow, J., Nelson, C., and Agterberg, D. Tunneling magnetoresistance and quantum oscillations in bilayered Ca3Ru2O7. Phys. Rev. B 67, 060406...

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


361

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

Group Photos August 2013: John with the Beamline Advisory Team for the SIX project at NSLS-II. The preparations for the external building for SIX can be seen in the background....

362

Photon Sciences | Beamlines | CHX: Coherent Hard X-ray Scattering...  

NLE Websites -- All DOE Office Websites (Extended Search)

exceeding, for a photon energy near E8 keV, 1021 phsmrad2mm20.1 % bw (more than one order of magnitude higher than that of the Advanced Photon Source), the CHX beamline will...

363

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

highlights Quantum Persistence of Magnetic Excitations in Overdoped High Temperature Superconductors Novel Magnetic Dispersions by Mixing Ir and Cu Materials Today Popular...

364

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

T., and Billinge, S. Local structural investigation of SmFeAsO1-xFx high temperature superconductors. J. Phys.: Condens. Matter 23, 272201 (2011). Partzsch, S., Wilkins,...

365

Femtosecond X-Rays from 90{degree} Thomson Scattering  

E-Print Network (OSTI)

system allows single bunch measurement of beam emittance, energy, charge and bunch length. The main laser

Leemans, W.

2008-01-01T23:59:59.000Z

366

NIST X-Ray Form Factor, Atten., and Scattering Database ...  

Science Conference Proceedings (OSTI)

... and Liberman while much of the experimental data was synthesised by ... for the range of Z and energy of general ... the range of Z and energies, and in ...

2010-10-05T23:59:59.000Z

367

Time-resolved x-ray scattering instrumentation  

DOE Patents (OSTI)

An apparatus and method for increased speed and efficiency of data compilation and analysis in real time is presented in this disclosure. Data is sensed and grouped in combinations in accordance with predetermined logic. The combinations are grouped so that a simplified reduced signal results, such as pairwise summing of data values having offsetting algebraic signs, thereby reducing the magnitude of the net pair sum. Bit storage requirements are reduced and speed of data compilation and analysis is increased by manipulation of shorter bit length data values, making real time evaluation possible.

Borso, C.S.

1985-11-21T23:59:59.000Z

368

Fourteenth National School on Neutron and X-ray Scattering  

E-Print Network (OSTI)

either nuclear physics parameters such as the effective delayed neutron fraction, or the so- called several new features in the physics of the ADS that require further development of the theory of neutron / q 3.784= #12;Neutron Fluctuations in Reactors R111 The physical reason for the above

Pennycook, Steve

369

Thirteenth National School on Neutron and X-ray Scattering  

E-Print Network (OSTI)

Spallation-Driven Cold Neutron Sources Dr. Bradley J. Micklich Senior Physicist, Physics Division physics research Want neutron wavelengths about the dimensions of interest, or neutron energies that can using an intense source of longerwavelength neutrons ­ fundamental nuclear physics (neutron halflife

370

National School on Neutron and X-ray Scattering  

E-Print Network (OSTI)

Cooling of isolated neutron stars as a probe of superdense matter physics Alexander Kaminker physics Alexander Kaminker 1. Introduction Microscopic theories of superdense matter in neutron star cores #12;Cooling of isolated neutron stars as a probe of superdense matter physics Alexander Kaminker

371

X-Ray Scattering Group, Condensed Matter Physics & Materials...  

NLE Websites -- All DOE Office Websites (Extended Search)

of Groningen Josh Turner LCLS Mary Upton Argonne National Lab Julian Baumert Yuguang Cai University of Kentucky Antonio Checco Soft Matter Group, BNL Scott Coburn NSLSII, BNL...

372

Probing warm dense lithium by inelastic X-ray scattering  

E-Print Network (OSTI)

-26000, NWFP, Pakistan 9 Institut f¨ur Kernphysik, Technische Universit¨at Darmstadt, Schlo�gartenstr. 9-temperature superconductors and nuclear matter1 . Warm dense matter, defined by temperatures of a few electron volts

Loss, Daniel

373

Ultra-short wavelength x-ray system  

DOE Patents (OSTI)

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

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

2008-01-22T23:59:59.000Z

374

NIST X-Ray Mass Attenuation Coefficients - Version History  

Science Conference Proceedings (OSTI)

... year, month day with database access date.) Hubbell, JH and Seltzer, SM (2004), Tables of X-Ray Mass Attenuation Coefficients and Mass Energy- ...

2010-10-05T23:59:59.000Z

375

4D Functional Materials Science with X-ray Microscopy  

Science Conference Proceedings (OSTI)

Ultrafast Electron Diffraction Studies of Lattice Dynamics in Thin Bismuth Films · Understanding Fatigue and Corrosion-Fatigue Behavior by In Situ 3D X-ray ...

376

Optical and X-ray Imaging Techniques for Material Characterization ...  

Science Conference Proceedings (OSTI)

Ultrafast X-ray and 2-dimensional UV Spectroscopy of TiO2 Nanoparticles: Majed Chergui1; 1Ecole Polytechnique Fédérale de Lausanne Mesoporous titanium ...

377

X-Ray and Neutron Diffraction - Programmaster.org  

Science Conference Proceedings (OSTI)

Oct 20, 2010 ... Strain Determination in Nanoscale Microelectronic Materials Using X-Ray Diffraction: Conal Murray1; 1IBM T.J. Watson Research Center

378

High Temperature X-ray Diffraction Characterization of Thermal ...  

Science Conference Proceedings (OSTI)

Application of Conical Beam X-Ray Tomography to Multi-Phase Materials ... Digital Construction and Characterization of Reticulated Porous Microstructures ...

379

dosimetry of x-rays, gamma rays and electrons  

Science Conference Proceedings (OSTI)

... NIST and BIPM Standards for Air Kerma in Medium-Energy X-rays ... of the codes are available from the Government Printing Office, Washington, DC ...

2013-06-28T23:59:59.000Z

380

APS X-ray Optics Fabrication and Characterization Facility  

SciTech Connect

The APS is in the process of assembling an X-ray Optics Fabrication and characterization Facility. This report will describe its current (as of February 1993) design.

Davey, S.

1993-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

X-ray compass for determining device orientation  

DOE Patents (OSTI)

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

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

1999-06-15T23:59:59.000Z

382

Synchrotron X-ray Studies of Supercritical Carbon Dioxide/ Reservoir...  

Open Energy Info (EERE)

Edit with form History Facebook icon Twitter icon Synchrotron X-ray Studies of Supercritical Carbon Dioxide Reservoir Rock Interfaces Geothermal Lab Call Project Jump to:...

383

Phase Sensitive X-ray Imager for More Accurate Digital ...  

Livermore Lab Report. News Archive. News ... use of higher energy X-rays which would result in a lower amount of absorbed radiation to the ... testing ...

384

Neutron and X-Ray Studies of Advanced Materials IV  

Science Conference Proceedings (OSTI)

We propose to organize a seven-session Symposium on Neutron and X-Ray ... the advent of new powerful neutron sources such as the Spallation Neutron ...

385

Available Technologies: High Temperature Strain Cell for X-ray ...  

High Temperature Strain Cell for X-ray ... Six hexapole infrared lamps focus inside the sample chamber onto a ceramic material sample with a spherical ...

386

X-ray compass for determining device orientation  

DOE Patents (OSTI)

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

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

1999-01-01T23:59:59.000Z

387

SLAC National Accelerator Laboratory - X-ray Laser Pulses in...  

NLE Websites -- All DOE Office Websites (Extended Search)

SLAC researchers have demonstrated for the first time how to produce pairs of X-ray laser pulses in slightly different wavelengths, or colors, with finely adjustable intervals...

388

NIST X-Ray Transition Energies Version History  

Science Conference Proceedings (OSTI)

... Jr., P. Indelicato, L. de Billy, E. Lindroth, and J. Anton, "X-ray transition energies: new approach to a ... [Type of medium] Available: URL [Access date]. ...

2010-10-05T23:59:59.000Z

389

Optical and X-ray Imaging Techniques for Material Characterization  

Science Conference Proceedings (OSTI)

Hyperspectral CARS Microscopy in the Fingerprint Region · In Situ X-ray ... Opportunities for Multimodal CARS Microscopy in Materials Science · Photoemission ...

390

Particle Accelerator & X-Ray Optics | Argonne National Laboratory  

NLE Websites -- All DOE Office Websites (Extended Search)

Hard X-Ray Quad Collimator Facilitates Microcrystallography Experiments Isotopic Abundance in Atom Trap Trace Analysis Nanomaterials Analysis using a Scanning Electron Microscope...

391

X RAY TU E WITH MAGNETI ELE TRON STEERING  

Sandia National Laboratories has created an improved efficiency compact X-ray source to address a wide range ... escape the anode and cause electron h ...

392

Temporal multiplexing radiography for dynamic x-ray imaging  

Science Conference Proceedings (OSTI)

All current x-ray imaging devices acquire images sequentially, one at a time. Using a spatially distributed multibeam x-ray source we recently demonstrated the feasibility for multiplexing x-ray imaging, which can significantly increase the data collection speed. Here we present a general methodology for dynamic x-ray imaging of an object in cyclic motion with temporal multiplexing. Compared to the conventional sequential imaging technique, where 2N-1 phase images are required and N exposures are needed for a single phase image, a temporal multiplexing of dimension 2N-1 can reduce the imaging time by a factor of N while maintaining the temporal resolution.

Cao Guohua [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Zhang Jian [Department of Radiation Oncology and Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Zhou, Otto; Lu Jianping [Department of Physics and Astronomy and Curriculum in Applied Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina, 27599 (United States)

2009-09-15T23:59:59.000Z

393

Refractive Optics for Hard X-ray Transmission Microscopy  

Science Conference Proceedings (OSTI)

For hard x-ray transmission microscopy at photon energies higher than 15 keV we design refractive condenser and imaging elements to be used with synchrotron light sources as well as with x-ray tube sources. The condenser lenses are optimized for low x-ray attenuation--resulting in apertures greater than 1 mm--and homogeneous intensity distribution on the detector plane, whereas the imaging enables high-resolution (condenser and imaging lenses are being developed. The imaging lenses (compound refractive lenses, CRLs) are made of SU-8 negative resist by deep x-ray lithography. SU-8 shows high radiation stability. The fabrication technique enables high-quality lens structures regarding surface roughness and arrangement precision with arbitrary 2D geometry. To provide point foci, crossed pairs of lenses are used. Condenser lenses have been made utilizing deep x-ray lithographic patterning of thick SU-8 layers, too, whereas in this case, the aperture is limited due to process restrictions. Thus, in terms of large apertures, condenser lenses made of structured and rolled polyimide film are more attractive. Both condenser types, x-ray mosaic lenses and rolled x-ray prism lenses (RXPLs), are considered to be implemented into a microscope setup. The x-ray optical elements mentioned above are characterized with synchrotron radiation and x-ray laboratory sources, respectively.

Simon, M.; Last, A.; Mohr, J.; Nazmov, V.; Reznikova, E. [Institute for Microstructure Technology, Karlsruhe Institute of Technology Kaiserstrasse 12, 76131 Karlsruhe (Germany); Ahrens, G.; Voigt, A. [Microresist Technology, Koepenikerstrasse 325, 12555 Berlin (Germany)

2011-09-09T23:59:59.000Z

394

SLAC National Accelerator Laboratory - X-ray Science  

NLE Websites -- All DOE Office Websites (Extended Search)

energy technologies. SLAC's unique X-ray facilities - the Linac Coherent Light Source (LCLS) and the Stanford Synchrotron Radiation Lightsource (SSRL) - attract thousands of...

395

Bibliography of NRL Works on X-Ray Fluorescence Authored ...  

Science Conference Proceedings (OSTI)

... LS Birks, and EJ Brooks, "Grain-Boundary Diffusion of Zinc in Copper ... 111 J. Gilfrich, "X-Ray Diffraction Studies on the Titanium-Nickel System," in ...

2012-10-05T23:59:59.000Z

396

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

NLE Websites -- All DOE Office Websites (Extended Search)

to accurately characterize the dynamic electrochemical processes at the nanometer and atomic level, we have employed a set of complementary, in situ X-ray characterization...

397

For Prospective Users: Learn about x-ray research  

NLE Websites -- All DOE Office Websites (Extended Search)

research in the fields of materials science; biological science; physics; chemistry; environmental, geophysical, and planetary science; and innovative x-ray instrumentation....

398

Improved Treatment of X-ray Resistant & Inoperable Cancers ...  

If the electron beam can be transported to the internal cancer without exposure to tissue, ... This figure shows a comparison of X-ray radiation ...

399

Spatially-Resolved X-Ray Microdiffraction Studies Inside Individual ...  

Science Conference Proceedings (OSTI)

This talk will describe recent advances including increased scanning speed, and will describe the use of this x-ray microscope to study mesoscale structural ...

400

Development of Coherent X-Ray Diffraction Microscopy and Its ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2010 TMS Annual Meeting & Exhibition. Symposium , Neutron and X-Ray Studies of Advanced Materials III. Presentation Title, 2010 ...

Note: This page contains sample records for the topic "angle x-ray scattering" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Background X-ray Spectrum of Radioactive Samples  

Science Conference Proceedings (OSTI)

An energy-dispersive X-ray spectrometer (EDS) is commonly used with a scanning electron microscope (SEM) to analyze the elemental compositions and microstructures of a variety of samples. For example, the microstructures of nuclear fuels are commonly investigated with this technique. However, the radioactivity of some materials introduces additional X-rays that contribute to the EDS background spectrum. These X-rays are generally not accounted for in spectral analysis software, and can cause misleading results. X-rays from internal conversion [1], Bremsstrahlung [2] radiation associated with alpha ionizations and beta particle interactions [3], and gamma rays from radioactive decay can all elevate the background of radioactive materials.

Shannon Yee; Dawn E. Janney

2008-02-01T23:59:59.000Z

402

Grain Boundary Deformation Analyzed Via X-Ray Diffraction ...  

Science Conference Proceedings (OSTI)

Modeling the Influence of the Second Phase Particle Spatial Distribution on Recrystallization of AA 7050 · Near-Field High Energy X-ray Diffraction Microscopy ...

403

Applications of High Resolution X-ray Computed Tomography in ...  

Science Conference Proceedings (OSTI)

... data, including concentration profiles from x-ray absorption measurements during ... Dynamic Evolution of Liquid-liquid Phase Separation While Cooling in a

404

Determining the Uncertainty of X-Ray Absorption ...  

Science Conference Proceedings (OSTI)

... The apparatus uses a tungsten filament and a tungsten target to generate x rays and the detector contains a CZT crystal. ...

2005-01-28T23:59:59.000Z

405

X-ray Detection with Large Area Avalanche Photodiodes for ...  

Science Conference Proceedings (OSTI)

... The primary photon detector was a 12-element ... The overall energy range for the experiment was ... to directly detect X-rays with energies between 0.3 ...

2013-07-23T23:59:59.000Z

406

Spectrometry of X-Ray Beams Used for Calibrations  

Science Conference Proceedings (OSTI)

... and used to calibrate a wavelength-dispersive crystal x-ray spectrograph used by Lawrence Livermore National Laboratory (LLNL) to diagnose ...

2012-06-26T23:59:59.000Z

407

X-ray Tube with Magnetic Electron Steering - Energy ...  

The high average power large area X-ray tube provides ... Solar Photovoltaic; Solar ... Description This invention consists of a cathode and anode ...

408

X-Ray Microdiffraction for VLSI  

Science Conference Proceedings (OSTI)

Energy windows, with resolutions Ehkl(2 )/Ehkl(2 )=0.03, were then opened in the multichannel analyzer (MCA), and the scattered intensities Ihkl were ...

409

X-ray Methods in High-Intensity Discharges and Metal-Halide Lamps: X-ray Induced Fluorescence  

SciTech Connect

We describe the use of x-ray induced fluorescence to study metal-halide high-intensity discharge lamps and to measure equilibrium vapor pressures of metal-halide salts. The physical principles of metal-halide lamps, relevant aspects of x-ray-atom interactions, the experimental method using synchrotron radiation, and x-ray induced fluorescence measurements relevant to metal-halide lamps are covered.

Curry, John J.; Lapatovich, Walter P.; Henins, Albert (NIST)

2011-12-09T23:59:59.000Z

410

Discovery of Two Types of X-ray Dips in Cyg X-1  

E-Print Network (OSTI)

We observed Cyg X-1 with {\\em RXTE} contiguously over its 5.6-day binary orbit. The source was found to be in the hard state throughout the observation. Many intensity dips were detected in the X-ray light curves. We found that the dips fell into two distinct categories based on their spectral properties. One type exhibits strong energy-dependent attenuation of X-ray emission at low energies during a dip, which is characteristic of photoelectric absorption, but the other type shows nearly energy-independent attenuation. While the first type of dips are likely caused by density enhancement in an inhomogeneous wind of the companion star, as previous studies have indicated, the second type might be due to partial obscuration of an extended X-ray emitting region by optically thick ``clumps'' in the accretion flow. It is also possible that the latter are caused by a momentary decrease in the X-ray luminosity of the source, due, for instance, to a decrease in the mass accretion rate, or by Thomson scattering in highly ionized ``clumps''. We discuss the implications of these scenarios.

Y. X. Feng; Wei Cui

2001-12-06T23:59:59.000Z

411

COSMIC-RAY AND X-RAY HEATING OF INTERSTELLAR CLOUDS AND PROTOPLANETARY DISKS  

SciTech Connect

Cosmic-ray and X-ray heating are derived from the electron energy-loss calculations of Dalgarno, Yan, and Liu for hydrogen-helium gas mixtures. These authors treated the heating from elastic scattering and collisional de-excitation of rotationally excited hydrogen molecules. Here we consider the heating that can arise from all ionization and excitation processes, with particular emphasis on the reactions of cosmic-ray and X-ray generated ions with the heavy neutral species, which we refer to as chemical heating. In molecular regions, chemical heating dominates and can account for 50% of the energy expended in the creation of an ion pair. The heating per ion pair ranges in the limit of negligible electron fraction from {approx}4.3 eV for diffuse atomic gas to {approx}13 eV for the moderately dense regions of molecular clouds and to {approx}18 eV for the very dense regions of protoplanetary disks. An important general conclusion of this study is that cosmic-ray and X-ray heating depends on the physical properties of the medium, i.e., on the molecular and electron fractions, the total density of hydrogen nuclei, and, to a lesser extent, on the temperature. It is also noted that chemical heating, the dominant process for cosmic-ray and X-ray heating, plays a role in UV irradiated molecular gas.

Glassgold, Alfred E. [Astronomy Department, University of California, Berkeley, CA 94720-3411 (United States); Galli, Daniele [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 (Italy); Padovani, Marco, E-mail: aglassgold@berkeley.edu, E-mail: galli@arcetri.astro.it, E-mail: marco.padovani@lra.ens.fr [Laboratoire de Radioastronomie Millimetrique, UMR 8112 du CNRS, Ecole Normale Superieure et Observatoire de Paris, 24 rue Lhomond, F-75231 Paris Cedex 05 (France)

2012-09-10T23:59:59.000Z

412

Angular Correlations of the X-Ray Background and Clustering of Extragalactic X-Ray Sources  

E-Print Network (OSTI)

The information content of the autocorrelation function (ACF) of intensity fluctuations of the X-ray background (XRB) is analyzed. The tight upper limits set by ROSAT deep survey data on the ACF at arcmin scales imply strong constraints on clustering properties of X-ray sources at cosmological distances and on their contribution to the soft XRB. If quasars have a clustering radius r_0=12-20 Mpc (H_0=50), and their two point correlation function, is constant in comoving coordinates as indicated by optical data, they cannot make up more 40-50% of the soft XRB (the maximum contribution may reach 80% in the case of stable clustering, epsilon=0). Active Star-forming (ASF) galaxies clustered like normal galaxies, with r_0=10-12 Mpc can yield up to 20% or up to 40% of the soft XRB for epsilon=-1.2 or epsilon=0, respectively. The ACF on degree scales essentially reflects the clustering properties of local sources and is proportional to their volume emissivity. The upper limits on scales of a few degrees imply that hard X-ray selected AGNs have r_06 deg, if real, may be due to AGNs with r_0=20 Mpc; the contribution from clusters of galaxies with r_0~50 Mpc is a factor 2 lower.

L. Danese; L. Toffolatti; A. Franceschini; J. M. Martin-Mirones; G. De Zotti

1993-02-24T23:59:59.000Z

413

Energy distribution measurement of narrow-band ultrashort x-ray beams via K-edge filters subtraction  

Science Conference Proceedings (OSTI)

The characterization of novel x-ray sources includes the measurement of the photon flux and the energy distribution of the produced beam. The aim of BEATS2 experiment at the SPARC-LAB facility of the INFN National Laboratories of Frascati (Rome, Italy) is to investigate possible medical applications of an x-ray source based on Thomson relativistic back-scattering. This source is expected to produce a pulsed quasi-monochromatic x-ray beam with an instantaneous flux of 10{sup 20} ph/s in pulses 10 ps long and with an average energy of about 20 keV. A direct measurement of energy distribution of this beam is very difficult with traditional detectors because of the extremely high photon flux. In this paper, we present a method for the evaluation of the energy distribution of quasi-monochromatic x-ray beams based on beam filtration with K-edge absorbing foils in the energy range of interest (16-22 keV). The technique was tested measuring the energy distribution of an x-ray beam having a spectrum similar to the expected one (SPARC-LAB Thomson source) by using a tungsten anode x-ray tube properly filtered and powered. The energy distribution obtained has been compared with the one measured with a HPGe detector showing very good agreement.

Cardarelli, Paolo; Di Domenico, Giovanni; Marziani, Michele; Mucollari, Irena; Pupillo, Gaia; Sisini, Francesco; Taibi, Angelo; Gambaccini, Mauro [Dipartimento di Fisica, Universita di Ferrara and INFN - Ferrara, via Saragat 1, I-44122 Ferrara (Italy)

2012-10-01T23:59:59.000Z

414

GRB 071112C: A CASE STUDY OF DIFFERENT MECHANISMS IN X-RAY AND OPTICAL TEMPORAL EVOLUTION  

SciTech Connect

We present a study on GRB 071112C X-ray and optical light curves. In these two wavelength ranges, we have found different temporal properties. The R-band light curve showed an initial rise followed by a single power-law decay, while the X-ray light curve was described by a single power-law decay plus a flare-like feature. Our analysis shows that the observed temporal evolution cannot be described by the external shock model in which the X-ray and optical emission are produced by the same emission mechanism. No significant color changes in multi-band light curves and a reasonable value of the initial Lorentz factor ({Gamma}{sub 0} = 275 {+-} 20) in a uniform interstellar medium support the afterglow onset scenario as the correct interpretation for the early R band rise. The result suggests that the optical flux is dominated by afterglow. Our further investigations show that the X-ray flux could be created by an additional feature related to energy injection and X-ray afterglow. Different theoretical interpretations indicate the additional feature in X-ray can be explained by either late internal dissipation or local inverse-Compton scattering in the external shock.

Huang, K. Y.; Tung, Y. H.; Lin, H. M.; Wang, S. Y.; Lehner, M. J.; Wang, J. H.; Wen, C. Y. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Urata, Y.; Ip, W. H. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Xin, L. P.; Qiu, Y.; Wei, J. [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Yoshida, M. [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Zheng, W.; Akerlof, C. [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Bianco, F. B. [Department of Physics, University of California Santa Barbara, Mail Code 9530, Santa Barbara, CA 93106-9530 (United States); Kawai, N. [Department of Physics, Tokyo Institute of Technology, 2-21-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Kuroda, D. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Kamogata, Asakuchi, Okayama 719-0232 (Japan); Marshall, S. L. [Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, MS 29, Menlo Park, CA 94025 (United States); Schwamb, M. E. [Department of Physics, Yale University, P.O. Box 208121, New Haven, CT 06520-8121 (United States); and others

2012-03-20T23:59:59.000Z

415

X-RAY SUBSTRUCTURE STUDIES OF FOUR GALAXY CLUSTERS USING XMM-NEWTON DATA  

SciTech Connect

Mahdavi et al. find that the degree of agreement between weak lensing and X-ray mass measurements is a function of cluster radius. Numerical simulations also point out that X-ray mass proxies do not work equally well at all radii. The origin of the effect is thought to be associated with cluster mergers. Recent work presenting the cluster maps showed an ability of X-ray maps to reveal and study cluster mergers in detail. Here, we present a first attempt to use the study of substructure in assessing the systematics of the hydrostatic mass measurements using two-dimensional (2D) X-ray diagnostics. The temperature map is uniquely able to identify the substructure in an almost relaxed cluster which would be unnoticed in the intracluster medium electron number density and pressure maps. We describe the radial fluctuations in the 2D maps by a cumulative/differential scatter profile relative to the mean profile within/at a given radius. The amplitude indicates {approx}10% fluctuations in the temperature, electron number density, and entropy maps, and {approx}15% fluctuations in the pressure map. The amplitude of and the discontinuity in the scatter complement 2D substructure diagnostics, e.g., indicating the most disturbed radial range. There is a tantalizing link between the substructure identified using the scatter of the entropy and pressure fluctuations and the hydrostatic mass bias relative to the expected mass based on the M-Y{sub X} and M-M{sub gas} relations particularly at r{sub 500}. XMM-Newton observations with {approx}120,000 source photons from the cluster are sufficient to apply our substructure diagnostics via the spectrally measured 2D temperature, electron number density, entropy, and pressure maps.

Zhang Yuying; Reiprich, Thomas H.; Hudson, Daniel S. [Argelander Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, 53121 Bonn (Germany); Finoguenov, Alexis [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Sarazin, Craig L. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)

2009-07-10T23:59:59.000Z

416

X-ray spectral states of microquasars  

E-Print Network (OSTI)

We discuss the origin of the dramatically different X-ray spectral shapes observed in the Low Hard State (LHS: dominated by thermal comptonisation) and the High Soft State (HSS: dominated by the accretion disc thermal emission and non-thermal comptonisation in the corona). We present numerical simulations using a new code accounting for the so-called synchrotron boiler effect. These numerical simulations when compared to the data allow us to constrain the magnetic field and temperature of the hot protons in the corona. For the hard state of Cygnus X-1 we find a magnetic field below equipartition with radiation, suggesting that the corona is not powered through magnetic field dissipation (as assumed in most accretion disc corona models). On the other hand, our results also point toward proton temperatures that are substantially lower than typical temperatures of the ADAF models. Finally, we show that in both spectral states Comptonising plasma could be powered essentially through power-law acceleration of non-thermal electrons, which are then partly thermalised by the synchrotron and Coulomb boiler. This suggests that, contrary to current beliefs, the corona of the HSS and that of the LHS could be of very similar nature. The differences between the LHS and HSS coronal spectra would then be predominantly caused by the strong disc soft cooling emission which is present in the HSS and absent in the LHS.

Julien Malzac; Renaud Belmont

2008-10-25T23:59:59.000Z

417

X-ray attenuation properties of stainless steel (u)  

SciTech Connect

Stainless steel vessels are used to enclose solid materials for studying x-ray radiolysis that involves gas release from the materials. Commercially available stainless steel components are easily adapted to form a static or a dynamic condition to monitor the gas evolved from the solid materials during and after the x-ray irradiation. Experimental data published on the x-ray attenuation properties of stainless steel, however, are very scarce, especially over a wide range of x-ray energies. The objective of this work was to obtain experimental data that will be used to determine how a poly-energetic x-ray beam is attenuated by the stainless steel container wall. The data will also be used in conjunction with MCNP (Monte Carlos Nuclear Particle) modeling to develop an accurate method for determining energy absorbed in known solid samples contained in stainless steel vessels. In this study, experiments to measure the attenuation properties of stainless steel were performed for a range of bremsstrahlung x-ray beams with a maximum energy ranging from 150 keV to 10 MeV. Bremsstrahlung x-ray beams of these energies are commonly used in radiography of engineering and weapon components. The weapon surveillance community has a great interest in understanding how the x-rays in radiography affect short-term and long-term properties of weapon materials.

Wang, Lily L [Los Alamos National Laboratory; Berry, Phillip C [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

418

Hard X-ray Phase Contrast -Techniques and Applications -  

E-Print Network (OSTI)

Hard X-ray Phase Contrast Microscopy - Techniques and Applications - A Dissertation Presented of the Graduate School ii #12;Abstract of the Dissertation Hard X-ray Phase Contrast Microscopy - Techniques . . . . . . . . . . . . . . . . . . 58 3.2.4 Reconstruction Example for Integration Method . . . . 59 3.2.5 The Imaginary Part

419

High-energy x-ray production with pyroelectric crystals  

Science Conference Proceedings (OSTI)

The invention of pyroelectric x-ray generator technology has enabled researchers to develop ultraportable, low-power x-ray sources for use in imaging, materials analysis, and other applications. For many applications, the usefulness of an x-ray source is determined by its yield and endpoint energy. In x-ray fluorescence, for example, high-energy sources enable the excitation of the K-shell x-ray peaks for high-Z materials as well as the lower-energy L-shell peaks, allowing more positive sample identification. This report shows how a paired-crystal pyroelectric source can be used to approximately double the endpoint x-ray energy, in addition to doubling the x-ray yield, versus a single-crystal source. As an example of the advantage of a paired-crystal system, we present a spectrum showing the fluorescence of the K shell of thorium using a pyroelectric source, as well as a spectrum showing the fluorescence of the K shell of lead. Also shown is an x-ray spectrum with an endpoint energy of 215 keV.

Geuther, Jeffrey A.; Danon, Yaron [Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2005-05-15T23:59:59.000Z

420

Improved Anti-Scatter Grids and Collimators  

Office of Technology Transfer Improved Anti-Scatter Grids and Collimators New Fabrication Method Enhances X-Ray, Nuclear Imaging to Save Lives, Reduce ...

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421

Flat Quartz-Crystal X-ray Spectrometer for Nuclear Forensics Applications  

E-Print Network (OSTI)

The ability to quickly and accurately quantify the plutonium (Pu) content in pressurized water reactor (PWR) spent nuclear fuel (SNF) is critical for nuclear forensics purposes. One non-destructive assay (NDA) technique being investigated to detect bulk Pu in SNF is measuring the self-induced x-ray fluorescence (XRF). Previous XRF measurements of Three Mile Island (TMI) PWR SNF taken in July 2008 and January 2009 at Oak Ridge National Laboratory (ORNL) successfully illustrated the ability to detect the 103.7 keV x ray from Pu using a planar high-purity germanium (HPGe) detector. This allows for a direct measurement of Pu in SNF. Additional gamma ray and XRF measurements were performed on TMI SNF at ORNL in October 2011 to measure the signal-to-noise ratio for the 103.7 keV peak. Previous work had shown that the Pu/U peak ratio was directly proportional to the Pu/U content and increased linearly with burnup. However, the underlying Compton background significantly reduced the signal-to-noise ratio for the x-ray peaks of interest thereby requiring a prolonged count time. Comprehensive SNF simulations by Stafford et al showed the contributions to the Compton continuum were due to high-energy gamma rays scattering in the fuel, shipping tube, cladding, collimator and detector1. The background radiation was primarily due to the incoherent scattering of the 137Cs 661.7 keV gamma. In this work methods to reduce the Compton background and thereby increase the signal-to-noise ratio were investigated. To reduce the debilitating effects of the Compton background, a crystal x-ray spectrometer system was designed. This wavelength-dispersive spectroscopy technique isolated the Pu and U x rays according to Bragg's law by x-ray diffraction through a crystal structure. The higher energy background radiation was blocked from reaching the detector using a customized collimator and shielding system. A flat quartz-crystal x-ray spectrometer system was designed specifically to fit the constraints and requirements of detecting XRF from SNF. Simulations were performed to design and optimize the collimator design and to quantify the improved signal-to-noise ratio of the Pu and U x-ray peaks. The proposed crystal spectrometer system successfully diffracted the photon energies of interest while blocking the high-energy radiation from reaching the detector and contributing to background counts. The spectrometer system provided a higher signal-to-noise ratio and lower percent error for the XRF peaks of interest from Pu and U. Using the flat quartz-crystal x-ray spectrometer and customized collimation system, the Monte Carlo N-Particle (MCNP) simulations showed the 103.7 keV Pu x-ray peak signal-to-noise ratio improved by a factor of 13 and decreased the percent error by a factor of 3.3.

Goodsell, Alison

2012-08-01T23:59:59.000Z

422

Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism  

NLE Websites -- All DOE Office Websites (Extended Search)

Unexpected Angular Dependence of Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Wednesday, 29 August 2007 00:00 Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and x-ray polarization, but their orientation relative to the crystallographic axes must be taken into account for accurate interpretation of XMLD data. Magnetism and X Rays

423

Broadband high resolution X-ray spectral analyzer  

DOE Patents (OSTI)

A broad bandwidth high resolution x-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces x-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available x-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for x-ray microanalysis or in research applications such as laboratory and astrophysical x-ray and particle spectroscopy.

Silver, Eric H. (Berkeley, CA); Legros, Mark (Berkeley, CA); Madden, Norm W. (Livermore, CA); Goulding, Fred (Lafayette, CA); Landis, Don (Pinole, CA)

1998-01-01T23:59:59.000Z

424

X-Ray Observations of Gamma-Ray Burst Afterglows  

E-Print Network (OSTI)

The discovery by the BeppoSAX satellite of X-ray afterglow emission from the gamma-ray burst which occurred on 28 February 1997 produced a revolution in our knowledge of the gamma-ray burst phenomenon. Along with the discovery of X-ray afterglows, the optical afterglows of gamma-ray bursts were discovered and the distance issue was settled, at least for long $\\gamma$-ray bursts. The 30 year mystery of the gamma-ray burst phenomenon is now on the way to solution. Here I rewiew the observational status of the X-ray afterglow emission, its mean properties (detection rate, continuum spectra, line features, and light curves), and the X-ray constraints on theoretical models of gamma-ray bursters and their progenitors. I also discuss the early onset afterglow emission, the remaining questions, and the role of future X-ray afterglow observations.

Filippo Frontera

2004-06-25T23:59:59.000Z

425

Broadband high resolution X-ray spectral analyzer  

DOE Patents (OSTI)

A broad bandwidth high resolution X-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces X-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available X-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for X-ray microanalysis or in research applications such as laboratory and astrophysical X-ray and particle spectroscopy. 6 figs.

Silver, E.H.; Legros, M.; Madden, N.W.; Goulding, F.; Landis, D.

1998-07-07T23:59:59.000Z

426

USING THE X-RAY EMISSION LINES OF SEYFERT 2 AGN TO MEASURE ABUNDANCE RATIOS  

E-Print Network (OSTI)

We measure the metal abundance ratios in the X-ray photoionized gas located near the narrow line region of a sample of Seyfert 2 AGN. The high-resolution X-ray spectra observed with the Chandra high- and low-energy transmission grating spectrometers are compared with models of the resonant scattering and recombination emission from a plasma in thermal balance, and with multiple temperature zones. The abundance ratios in the sample are close to the Solar values, with slight over-abundances of N in NGC 1068, and of Ne in NGC 4151. Our X-ray spectral models use fewer degrees of freedom than previous works. Motivation. Our goal is to use X-ray abundance measurements to cross-calibrate with the optical spectra of quasars. These optical spectra are used to measure the star formation history of the early Universe. 1 To Determine the Abundance Ratios, we fit the Seyfert 2 spectra with models of photoionized plasmas, and then search for deviations in the data from Solar abundances, as shown in Fig. 1. The fluxes of radiative recombination continuum (RRC) features and the radiative recombination (RR) forbidden lines depend little on radiation transfer effects, so they are the most reliable abundance indicators. At low continuum optical depths, the recombination emission flux scales linearly with abundances. Our model allows us to fit the RRC and RR fluxes by accounting for the broad ionization distribution in the plasma. X-ray Emission Line Model. We model a photoionized plasma in ionization equilibrium and thermal balance with a grid of zones, each with ionization parameter log ? = 1.0, 1.5,...4.5 (in c.g.s. units). The XSTAR plasma code yields the charge state distribution of each zone. 2 In order to calculate the recombination emission, we use the photoelectric cross sections

Mario A. Jimenez-garate; Toan Khu

2004-01-01T23:59:59.000Z

427

{gamma}Z corrections to forward-angle parity-violating ep scattering  

Science Conference Proceedings (OSTI)

We use dispersion relations to evaluate the {gamma}Z box contribution to parity-violating electron scattering in the forward limit arising from the axial-vector coupling at the electron vertex. The calculation makes full use of the critical constraints from recent JLab data on electroproduction in the resonance region as well as high-energy data from HERA. At the kinematics of the Q{sub weak} experiment, this gives a correction of 0.0047{sub -0.0004}{sup +0.0011} to the standard model value 0.0713(8) of the proton weak charge. While the magnitude of the correction is highly significant, the uncertainty is within the anticipated experimental uncertainty of {+-}0.003.

Sibirtsev, A. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Universitaet Bonn, D-53115 Bonn (Germany); Jefferson Lab, 12000 Jefferson Avenue, Newport News, Virginia 23606 (United States); Blunden, P. G. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2 (Canada); Jefferson Lab, 12000 Jefferson Avenue, Newport News, Virginia 23606 (United States); Melnitchouk, W. [Jefferson Lab, 12000 Jefferson Avenue, Newport News, Virginia 23606 (United States); Thomas, A. W. [CSSM, School of Chemistry and Physics, University of Adelaide, Adelaide SA 5005 (Australia)

2010-07-01T23:59:59.000Z

428

Enhancement of Terrestrial Diffuse X-ray Emission Associated With Coronal Mass Ejection and Geomagnetic Storm  

E-Print Network (OSTI)

We present an analysis of a Suzaku observation taken during the geomagnetic storm of 2005 August 23-24. We found time variation of diffuse soft X-ray emission when a coronal mass ejection hit Earth and caused a geomagnetic storm. The diffuse emission consists of fluorescent scattering of solar X-rays and exospheric solarwind charge exchange. The former is characterized by a neutral oxygen emission line due to strong heating of the upper atmosphere during the storm time, while the latter is dominated by a sum of C V, C VI, N VI, N VII, O VII, and O VIII emission lines due to the enhanced solar wind flux in the vicinity of the exosphere. Using the solar wind data taken with the ACE and WIND satellites,a time correlation between the solar wind and the strong O VII line flux were investigated. We estimated necessary column densities for the solar X-ray scattering and exospheric SWCX. From these results, we argue that a part of the solar wind ions enter inside the magnetosphere and cause the SWCX reaction.

Ezoe, Yuichiro; Yoshitake, Hiroshi; Mitsuda, Kazuhisa; Terada, Naoki; Oishi, Shihoko; Ohashi, Takaya

2011-01-01T23:59:59.000Z

429

Crosscheck of different techniques for two dimensional power spectral density measurements of x-ray optics  

Science Conference Proceedings (OSTI)

The consistency of different instruments and methods for measuring two-dimensional (2D) power spectral density (PSD) distributions are investigated. The instruments are an interferometric microscope, an atomic force microscope (AFM) and the X-ray Reflectivity and Scattering experimental facility, all available at Lawrence Berkeley National Laboratory. The measurements were performed with a gold-coated mirror with a highly polished stainless steel substrate. It was shown that these three techniques provide essentially consistent results. For the stainless steel mirror, an envelope over all measured PSD distributions can be described with an inverse power-law PSD function. It is also shown that the measurements can be corrected for the specific spatial frequency dependent systematic errors of the instruments. The AFM and the X-ray scattering measurements were used to determine the modulation transfer function of the interferometric microscope. The corresponding correction procedure is discussed in detail. Lower frequency investigation of the 2D PSD distribution was also performed with a long trace profiler and a ZYGO GPI interferometer. These measurements are in some contradiction, suggesting that the reliability of the measurements has to be confirmed with additional investigation. Based on the crosscheck of the performance of all used methods, we discuss the ways for improving the 2D PSD characterization of X-ray optics.

Yashchuk, Valeriy V.; Irick, Steve C.; Gullikson, Eric M.; Howells, Malcolm R.; MacDowell, Alastair A.; McKinney, Wayne R.; Salmassi, Farhad; Warwick, Tony

2005-07-12T23:59:59.000Z

430

In-Situ Observation of Solid Electrolyte Interphase Formation in Ordered Mesoporous Hard Carbon by Small-Angle Neutron Scattering  

Science Conference Proceedings (OSTI)

The aim of this work was to better understand the electrochemical processes occurring during the cycling of a lithium-ion half-cell containing ordered mesoporous hard carbon using time-resolved in situ small-angle neutron scattering (SANS). Utilizing electrolytes containing mixtures of deuterated (2H) and non-deuterated (1H) carbonates, we have addressed the challenging task of monitoring the formation and evolution of the solid-electrolyte interphase (SEI) layer. An evolution occurs in the SEI layer during discharge from a composition dominated by a higher scattering length density (SLD) lithium salt, to a lower SLD lithium salt for the ethylene carbonate/dimethyl carbonate (EC/DMC) mixture employed. By comparing half-cells containing different solvent deuteration levels, we show that it is possible to observe both SEI formation and lithium intercalation occurring concurrently at the low voltage region in which lithium intercalates into the hard carbon. These results demonstrate that SANS can be employed to monitor complicated electrochemical processes occurring in rechargeable batteries, in a manner that simultaneously provides information on the composition and microstructure of the electrode.

Bridges, Craig A [ORNL; Paranthaman, Mariappan Parans [ORNL; Sun, Xiao-Guang [ORNL; Zhao, Jinkui [ORNL; Dai, Sheng [ORNL

2012-01-01T23:59:59.000Z

431

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

SciTech Connect

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.

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)

2011-11-28T23:59:59.000Z

432

Fast-switching elliptically polarized soft X-ray beam X13A at NSLS  

SciTech Connect

The X13A beamline at NSLS is dedicated to the generation and uses of fast-switching elliptically polarized soft X-ray radiation in the energy range from 250 to {approx}1600 eV. The source for this beamline is an elliptically polarized wiggler (EPW) that delivers linearly elliptically polarized soft X-rays at a switching rate, between right- and left-handed polarization, up to 100 Hz. The optical design is a spherical grating monochromator (SGM) that focuses and diffracts in plane orthogonal to the polarization switching direction. The X13A beamline scientific program is dedicated to spectroscopy and scattering studies of magnetism and magnetic materials. The fast-switching capability of the EPW enables the use of lock-in techniques, thereby greatly enhancing the detection sensitivity for small polarization-dependent signals.

Sanchez-Hanke, C.; Kao, C.; Hulbert, S.

2009-07-21T23:59:59.000Z

433

Structure determination of thin CoFe films by anomalous x-ray diffraction  

Science Conference Proceedings (OSTI)

This work reports on the investigation of structure-property relationships in thin CoFe films grown on MgO. Because of the very similar scattering factors of Fe and Co, it is not possible to distinguish the random A2 (W-type) structure from the ordered B2 (CsCl-type) structure with commonly used x-ray sources. Synchrotron radiation based anomalous x-ray diffraction overcomes this problem. It is shown that as grown thin films and 300 K post annealed films exhibit the A2 structure with a random distribution of Co and Fe. In contrast, films annealed at 400 K adopt the ordered B2 structure.

Gloskovskii, Andrei; Stryganyuk, Gregory; Ouardi, Siham [Institut fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); Fecher, Gerhard H.; Felser, Claudia [Institut fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden (Germany); Hamrle, Jaroslav; Pistora, Jaromir [Department of Physics and Nanotechnology Centre, VSB-Technical University of Ostrava, 70833 Ostrava (Czech Republic); Bosu, Subrojati; Saito, Kesami; Sakuraba, Yuya; Takanashi, Koki [Institute for Materials Research (IMR), Tohoku University, Sendai 980-8577 (Japan)

2012-10-01T23:59:59.000Z

434

Biological Imaging by Soft X-Ray Diffraction Microscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Biological Imaging by Soft X-Ray Biological Imaging by Soft X-Ray Diffraction Microscopy Biological Imaging by Soft X-Ray Diffraction Microscopy Print Wednesday, 30 November 2005 00:00 Electron and x-ray microscopes are a valuable tool for both the life and materials sciences, but they are limited in their ability to image with nanometer-scale resolution in three dimensions nonperiodic objects that are several microns in size. To fill this gap, the technique of coherent x-ray diffraction imaging now under development takes advantage of the penetrating power of x rays while simultaneously removing the limitations imposed by lens-based optical systems. Researchers from Stony Brook University, in collaboration with scientists at the ALS and Cornell University, have taken a large step in this direction by using a lensless x-ray diffraction microscope to image a freeze-dried yeast cell to better than 30-nm resolution. Images were made at several angular orientations of the cell.

435

Resonant Auger Effect at High X-Ray Intensity  

SciTech Connect

The resonant Auger effect of atomic neon exposed to high-intensity x-ray radiation in resonance with the 1s {yields} 3p transition is discussed. High intensity here means that the x-ray peak intensity is sufficient ({approx} 10{sup 18} W/cm{sup 2}) to induce Rabi oscillations between the neon ground state and the 1s{sup -1}3p ({sup 1}P) state within the relaxation lifetime of the inner-shell vacancy. For the numerical analysis presented, an effective two-level model, including a description of the resonant Auger decay process, is employed. Both coherent and chaotic x-ray pulses are treated. The latter are used to simulate radiation from x-ray free-electron lasers based on the principle of self-amplified spontaneous emission. Observing x-ray-driven atomic population dynamics in the time domain is challenging for chaotic pulse ensembles. A more practical option for experiments using x-ray free-electron lasers is to measure the line profiles in the kinetic energy distribution of the resonant Auger electron. This provides information on both atomic population dynamics and x-ray pulse properties.

Rohringer, N; Santra, R

2008-03-27T23:59:59.000Z

436

X-ray emission from laser-produced plasmas  

SciTech Connect

The intensity and spectral characteristics of x-ray emitted from laser-produced plasmas have been investigated computatinoally and experimentally. a two-dimensional implosi code was used successfully to calculate laser-plasma radiation characteristics and to aid in the design of laser targets for high-yield x-ray production. Other computer codes, in use or under development predict lime strengths and energies for laser-plasma x-ray emission. An experimental effort is aimed at reliable measurements of x-ray yields and spectra. a wide variety of x-ray detection methods have been evaluated, and x-ray yields have been measured from plasmas produced with two dissimilar laser systems. The high energy x-ray spectrum, from about 10 to 140 keV, has been studied using high-gain scintillatino detectors and thick K-edge filters. Various supplementary measurements have provided information concerning characteristics of the target-reflected laser light, the ion energies, and the laser intensity patterns.

Violet, C.E. [ed.

1974-07-01T23:59:59.000Z

437

Optical systems for synchrotron radiation: lecture 4. Soft x-ray imaging systems  

Science Conference Proceedings (OSTI)

The history and present techniques of soft x-ray imaging are reviewed briefly. The physics of x-ray imaging is described, including the temporal and spatial coherence of x-ray sources. Particular technologies described are: contact x-ray microscopy, zone plate imaging, scanned image zone plate microscopy, scanned image reflection microscopy, and soft x-ray holography and diffraction. (LEW)

Howells, M.R.

1986-04-01T23:59:59.000Z

438

X-ray afterglows from gamma-ray bursts  

E-Print Network (OSTI)

We consider possible interpretations of the recently detected X- ray afterglow from the gamma-ray burst source GRB 970228. Cosmological and Galactic models of gamma-ray bursts predict different flux and spectral evolution of X-ray afterglows. We show that models based on adiabatic expansion of relativistic forward shocks require very efficient particle energization or post-burst re-acceleration during the expansion. Cooling neutron star models predict a very distinctive spectral and flux evolution that can be tested in current X-ray data.

M. Tavani

1997-03-24T23:59:59.000Z

439

Ten years of Vela x-ray observations  

SciTech Connect

The Vela spacecraft, particularly Vela 5B, produced all-sky X-ray data of unprecedented length and completeness. The data led to the discovery of X-ray bursts and numerous transient outbursts. Recent re-analysis has put the data in the form of 10-day skymaps covering a 7-year period,