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1

EFFECT OF SATELLITE LINES FROM X-RAY SOURCE ON X-RAY DIFFRACTION PEAKS  

EPA Science Inventory

The article discusses the development of a method for relating reactivity to crystallite size and strain parameters obtained by the Warren-Averbach technique. PA has been using crystallite size and strain data obtained from x-ray diffraction (XRD) peak profile analysis to predict...

2

X-Ray Diffraction.  

ERIC Educational Resources Information Center

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

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

1980-01-01

3

X-Ray Diffraction  

NSDL National Science Digital Library

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

Matter.org

4

X-ray Diffraction  

NSDL National Science Digital Library

A series of laboratory activities on x-ray diffraction physics using the Teltron Tel-X-Ometer System. Detailed explanations on the production and delivery of the beam is included, as well as a very complete safety protocol for conducting the experiments.

Langan, Shawn

2012-03-08

5

THE EFFECT OF SATELLITE LINES FROM THE X-RAY SOURCE ON X-RAY DIFFRACTION PEAKS  

EPA Science Inventory

The article discusses the development of a method for relating reactivity to crystallite size and strain parameters obtained by the Warren-Averbach technique. EPA has been using crystallite size and strain data obtained from x-ray diffraction (XRD) peak profile analysis to predic...

6

Examination of abraded MgO by X-Ray diffraction line broadening  

Microsoft Academic Search

X-ray diffraction line broadening has been used to study the deformation of MgO during abrasion and the effect of annealing on the deformed structure. These results are compared with published data for filed metals and MgO which has been deformed by other means. The results are consistent with a uniform distribution of dislocations in the abraded MgO, and with a

I. Cutter; R. McPherson

1969-01-01

7

X-Ray Diffraction Apparatus  

NASA Technical Reports Server (NTRS)

An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

1996-01-01

8

Submicron X-ray diffraction  

SciTech Connect

At the Advanced Light Source in Berkeley the authors have instrumented a beam line that is devoted exclusively to x-ray micro diffraction problems. By micro diffraction they mean those classes of problems in Physics and Materials Science that require x-ray beam sizes in the sub-micron range. The instrument is for instance, capable of probing a sub-micron size volume inside micron sized aluminum metal grains buried under a silicon dioxide insulating layer. The resulting Laue pattern is collected on a large area CCD detector and automatically indexed to yield the grain orientation and deviatoric (distortional) strain tensor of this sub-micron volume. A four-crystal monochromator is then inserted into the beam, which allows monochromatic light to illuminate the same part of the sample. Measurement of diffracted photon energy allows for the determination of d spacings. The combination of white and monochromatic beam measurements allow for the determination of the total strain/stress tensor (6 components) inside each sub-micron sized illuminated volume of the sample.

MacDowell, Alastair; Celestre, Richard; Tamura, Nobumichi; Spolenak, Ralph; Valek, Bryan; Brown, Walter; Bravman, John; Padmore, Howard; Batterman, Boris; Patel, Jamshed

2000-08-17

9

THE CHARACTERIZATION OF A SOLID SORBENT WITH CRYSTALLITE SIZE AND STRAIN DATA FROM X-RAY DIFFRACTION LINE BROADENING  

EPA Science Inventory

The paper gives results of the characterization of a solid sorbent with crystallite size and strain data from x-ray diffraction line broadening, as part of an EPA investigation of the injection of dry Ca(OH)2 into coal-fired electric power plant burners for the control of SO2 emi...

10

Focusing and imaging sharp line X-ray and gamma-ray sources using variable-metric diffraction crystals  

NASA Astrophysics Data System (ADS)

A new method was devised for focusing and imaging the radiation from sharp line sources of X-rays and gamma rays, which makes use of variable metric diffraction crystals. A variable metric diffraction crystal is one in which the spacings between the crystalline planes is varied as a function of position in the crystal by either the application of a thermal gradient or by changing the composition of a two component or multiple component crystal. This change in planar spacing changes the Bragg diffraction angle for monochromatic radition as a function of position in the crystal and makes it possible to obtain focusing and in some cases imaging of a sharp line point source or parallel beam source. This new approach to focusing X-rays and gamma rays is used to design a number of gamma ray telescopes suitable for focusing the 511 keV annihilation radiation from the strong source of the center of our galaxies.

Smither, R. K.

11

A line-broadening analysis model for the microstructural characterization of nanocrystalline materials from asymmetric x-ray diffraction peaks  

NASA Astrophysics Data System (ADS)

Nanograin sizes and crystal lattice microstrains in nanocrystalline materials are typically evaluated from the broadening of their x-ray diffraction (XRD) peaks under the assumption of symmetrical diffraction profiles. Since this assumption is not entirely satisfactory, we formulate a line-broadening analysis model of a single peak that considers explicitly the XRD peak asymmetry. The model is a generalization of the variance method in which the shape of the XRD peaks is idealized through asymmetrical split pseudo-Voigt functions. The model is validated on two nanocrystalline powders.

Pantoja-Cortés, Juan; Sánchez-Bajo, Florentino; Ortiz, Angel L.

2012-05-01

12

A line-broadening analysis model for the microstructural characterization of nanocrystalline materials from asymmetric x-ray diffraction peaks.  

PubMed

Nanograin sizes and crystal lattice microstrains in nanocrystalline materials are typically evaluated from the broadening of their x-ray diffraction (XRD) peaks under the assumption of symmetrical diffraction profiles. Since this assumption is not entirely satisfactory, we formulate a line-broadening analysis model of a single peak that considers explicitly the XRD peak asymmetry. The model is a generalization of the variance method in which the shape of the XRD peaks is idealized through asymmetrical split pseudo-Voigt functions. The model is validated on two nanocrystalline powders. PMID:22535886

Pantoja-Cortés, Juan; Sánchez-Bajo, Florentino; Ortiz, Angel L

2012-05-30

13

X-ray diffraction line profile analysis of deformation microstructure in boron modified Ti-6Al-4V alloy  

SciTech Connect

X-ray diffraction line profile analysis (XRDLPA) techniques have been applied to investigate the deformed microstructure of a recently developed boron modified two-phase titanium alloy Ti-6Al-4V. The alloy was hot compressed at 750 deg. C up to 50% height reduction at two different strain rates (10{sup -3} S{sup -1} and 1 S{sup -1}). Microstructural parameters like average domain size, average microstrain within the domain and dislocation density of the two phases were determined using X-ray diffraction line profile analysis. The results indicate an increase in the microstrain and dislocation density for the {alpha}-phase and decrease for the {beta}-phase in the case of boron modified alloys as compared to the normal material. Microstructural modifications viz. the grain refinement and the presence of hard, brittle TiB particles in the case of boron modified alloy are held responsible for the observed difference in the dislocation density. - Research Highlights: {yields} Microstructural examination of hot compressed Ti64 with and without boron addition by XRDLPA. {yields} Smaller average domain size in alpha-phase compared to the corresponding alpha-phase in all cases. {yields} Higher microstrain and dislocation density for {alpha} phase and lower for {beta} phase in case of Ti64+B. {yields} Decrease in domain size while increase in micro-strain and dislocation density with strain rate. {yields} Strain accumulation around TiB particles responsible for high dislocation density in {alpha} phase.

Sarkar, Apu; Roy, Shibayan; Suwas, Satyam, E-mail: satyamsuwas@materials.iisc.ernet.in

2011-01-15

14

Diffractive X-Ray Telescopes  

NASA Technical Reports Server (NTRS)

Diffractive X-ray telescopes, using zone plates, phase Fresnel lenses, or related optical elements have the potential to provide astronomers with true imaging capability with resolution many orders of magnitude better than available in any other waveband. Lenses that would be relatively easy to fabricate could have an angular resolution of the order of micro-arc-seconds or even better, that would allow, for example, imaging of the distorted spacetime in the immediate vicinity of the super-massive black holes in the center of active galaxies. What then is precluding their immediate adoption? Extremely long focal lengths, very limited bandwidth, and difficulty stabilizing the image are the main problems. The history, and status of the development of such lenses is reviewed here and the prospects for managing the challenges that they present are discussed.

Skinner, Gerald K.

2010-01-01

15

Oriented Graphite X-Ray Diffraction Telescope  

Microsoft Academic Search

A development program performed during the last year under a contract with the Office of Naval Research has indicated that diffraction focusing of X-rays may offer significant detection advantages when used to focus low energy gamma and X-radiation onto single detectors. The work which supports this conclusion includes a survey of diffraction crystalline materials, diffractometer X-ray measurements of selected crystal

J. B. Trice; R. J. Locker

1975-01-01

16

Beyond hard x-ray photoelectron spectroscopy: Simultaneous combination with x-ray diffraction  

SciTech Connect

Hard x-ray photoelectron spectroscopy (HAXPES) is a powerful and novel emerging technique for the nondestructive determination of electronic properties and chemical composition of bulk, buried interfaces and surfaces. It benefits from the exceptionally large escape depth of high kinetic energy photoelectrons, increasing the information depth up to several tens of nanometers. Complementing HAXPES with an atomic structure sensitive technique (such as x-ray diffraction) opens a new research field with major applications for materials science. At SpLine, the Spanish CRG beamline at the European Synchrotron Radiation Facility, we have developed a novel experimental set-up that combines HAXPES and x-ray diffraction (x-ray reflectivity, surface x-ray diffraction, grazing incidence x-ray diffraction, and reciprocal space maps). Both techniques can be operated simultaneously on the same sample and using the same excitation source. The set-up includes a robust 2S + 3D diffractometer hosting a ultrahigh vacuum chamber equipped with a unique photoelectron spectrometer (few eV < electron kinetic energy < 15 keV), x-ray tube (Mg/Ti), 15 keV electron gun, and auxiliary standard surface facilities (molecular beam epitaxy evaporator, ion gun, low energy electron diffraction, sample heating/cooling system, leak valves, load-lock sample transfer, etc.). This end-station offers the unique possibility of performing simultaneous HAXPES + x-ray diffraction studies. In the present work, we describe the experimental set-up together with two experimental examples that emphasize its outstanding capabilities: (i) nondestructive characterization of the Si/Ge and HfO{sub 2}/SiO{sub 2} interfaces on Ge-based CMOS devices, and (ii) strain study on La{sub 0.7}Ca{sub 0.3}MnO{sub 3} ultrathin films grown on SrTiO{sub 3}(001) substrate.

Rubio-Zuazo, Juan; Castro, German R. [SpLine, Spanish CRG beamline at the European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble (France) and ICMM-CSIC Cantoblanco, E-28049 Madrid (Spain)

2013-05-15

17

Single Particle X-ray Diffractive Imaging  

SciTech Connect

In nanotechnology, strategies for the creation and manipulation of nanoparticles in the gas phase are critically important for surface modification and substrate-free characterization. Recent coherent diffractive imaging with intense femtosecond X-ray pulses has verified the capability of single-shot imaging of nanoscale objects at sub-optical resolutions beyond the radiation-induced damage threshold. By intercepting electrospray-generated particles with a single 15 femtosecond soft-X-ray pulse, we demonstrate diffractive imaging of a nanoscale specimen in free flight for the first time, an important step toward imaging uncrystallized biomolecules.

Bogan, M J; Benner, W H; Boutet, S; Rohner, U; Frank, M; Seibert, M; Maia, F; Barty, A; Bajt, S; Riot, V; Woods, B; Marchesini, S; Hau-Riege, S P; Svenda, M; Marklund, E; Spiller, E; Hajdu, J; Chapman, H N

2007-10-01

18

The Dynamical Theory of X Ray Diffraction  

ERIC Educational Resources Information Center

Summarizes the Darwin theory of x-ray diffraction in thin crystals or crystals with a mosaic texture and its modified application to crystals with three-dimensional electrostatic dipoles. Indicates that the dynamical theory is brought into its present relevance by the improvement of single crystal growth techniques. (CC)

Balchin, A. A.; Whitehouse, C. R.

1974-01-01

19

X-ray powder diffraction line broadening analysis and magnetism of interacting ferrite nanoparticles obtained from acetylacetonato complexes  

Microsoft Academic Search

A study of the microstructures and magnetic properties of nanosize Zn ferrite (ZnFe2O4), Mn ferrite (MnFe2O4), and the cation deficit Zn-Mn ferrites Zn0.70Mn0.23Fe1.89O4 (S1), Zn0.41Mn0.50Fe1.84O4 (S2) and Zn0.18Mn0.67Fe1.85O4 (S3) was performed. The crystallite size for all samples was determined by x-ray powder diffraction (XRPD) analysis using four different methods, and was close to the particle size found from transmission electron

A. Kremenovic; B. Antic; V. Spasojevic; M. Vucinic-Vasic; Z. Jaglicic; J. Pirnat; Z. Trontelj

2005-01-01

20

Tomographic femtosecond X-ray diffractive imaging  

E-print Network

A method is proposed for obtaining three simultaneous projections of a target from a single radiation pulse, which also allows the relative orientation of successive targets to be determined. The method has application to femtosecond X-ray diffraction, and does not require solution of the phase problem. We show that the principle axes of a compact charge-density distribution can be obtained from projections of its autocorrelation function, which is directly accessible in diffraction experiments. The results may have more general application to time resolved tomographic pump-probe experiments and time-series imaging.

K. E. Schmidt; J. C. H. Spence; U. Weierstall; R. Kirian; X. Wang; D. Starodub; H. N. Chapman; M. R. Howells; R. B. Doak

2008-06-10

21

Optical properties of X-rays--dynamical diffraction.  

PubMed

The first attempts at measuring the optical properties of X-rays such as refraction, reflection and diffraction are described. The main ideas forming the basis of Ewald's thesis in 1912 are then summarized. The first extension of Ewald's thesis to the X-ray case is the introduction of the reciprocal lattice. In the next step, the principles of the three versions of the dynamical theory of diffraction, by Darwin, Ewald and Laue, are given. It is shown how the comparison of the dynamical and geometrical theories of diffraction led Darwin to propose his extinction theory. The main optical properties of X-ray wavefields at the Bragg incidence are then reviewed: Pendellösung, shift of the Bragg peak, fine structure of Kossel lines, standing waves, anomalous absorption, paths of wavefields inside the crystal, Borrmann fan and double refraction. Lastly, some of the modern applications of the dynamical theory are briefly outlined: X-ray topography, location of adsorbed atoms at crystal surfaces, optical devices for synchrotron radiation and X-ray interferometry. PMID:22186282

Authier, André

2012-01-01

22

X-ray diffraction with novel geometry  

NASA Astrophysics Data System (ADS)

An innovative geometry for high efficiency harvesting of diffracted X-rays is explored. Further to previous work where planar samples were fixed normal to the primary axis, this work extends focal construct geometry (FCG), to samples randomly oriented with respect to the incident beam. The effect of independent sample rotation around two axes upon the scattering distributions was investigated in analytical, simulation and empirical manners. It was found that, although the profile of Bragg maxima were modified when the sample was rotated, high intensity diffraction data was still acquired. Modelling produced a good match to the empirical data and it was shown that the distortions caused by sample rotation were not severe and predictable even when sample rotations were large. The implications for this are discussed.

Prokopiou, Danae; Rogers, Keith; Evans, Paul; Godber, Simon; Shackel, James; Dicken, Anthony

2014-01-01

23

X-Ray-Diffraction Tests Of Irradiated Electronic Devices: II  

NASA Technical Reports Server (NTRS)

Report describes research on use of x-ray diffraction to measure stresses in metal conductors of complementary metal oxide/semiconductor (CMOS) integrated circuits exposed to ionizing radiation. Expanding upon report summarized in "X-Ray-Diffraction Tests Of Irradiated Electronic Devices: I" (NPO-18803), presenting data further suggesting relationship between electrical performances of circuits and stresses and strains in metal conductors.

Shaw, David C.; Lowry, Lynn E.; Barnes, Charles E.

1993-01-01

24

Diffraction peaks in x ray spectroscopy: Friend or foe?  

NASA Astrophysics Data System (ADS)

Diffraction peaks can occur as unidentifiable peaks in the energy spectrum of an x-ray spectrometric analysis. Recently, there has been increased interest in oriented polycrystalline films and epitaxial films on single crystal substrates for electronic applications. Since these materials diffract x-rays more efficiently than randomly oriented polycrystalline materials, diffraction peaks are being observed more frequently in x-ray fluorescent spectra. In addition, micro x-ray spectrometric analysis utilizes a small, intense, collimated x-ray beam that can yield well defined diffraction peaks. In some cases these diffraction peaks can occur at the same position as elemental peaks. These diffraction peaks, although a possible problem in qualitative and quantitative elemental analysis, can give very useful information about the crystallographic structure and orientation of the material being analyzed. The observed diffraction peaks are dependent on the geometry of the x-ray spectrometer, the degree of collimation, and the distribution of wavelengths (energies) originating from the x-ray tube and striking the sample.

Tissot, R. G.; Goehner, R. P.

25

X-RAY DIFFRACTION STUDIES ON FROG MUSCLES.  

PubMed

1. X-ray diffraction studies of sartorius muscles of Rana pipiens were made in a new x-ray diffraction camera which permits exposures of 3 to 6 minutes. The object-film distance can be varied from 20 to 80 mm; the muscle inside the camera can be electrically stimulated while contracting isotonically or isometrically, and can be observed by a special device. After exposures up to 30 minutes (approximately 40,830 r) muscles are still alive and responsive. 2. Contrary to the x-ray diffraction pattern of powdered dry muscle, which pattern consists of two rings corresponding to spacings of 4.46 A.u. and 9.66 A.u., both moist and dried whole sartorius muscle show signs of orientation in both rings, consisting of two equatorial streaks (wet) or points (dry) and meridional sickles. The moist muscle shows in addition a diffuse water ring. The spacings corresponding to the orientation points and elliptical structure show only slight differences in moist and dried samples. Through statistical computations based on two different series consisting of thirteen moist and twenty-eight dried samples, and nine muscles before and after drying, it was shown that only the divergence in the smaller spacing has some real significance, which indicates that most water of the moist muscle is bound intermolecularly. Upon resoaking of dried muscle the x-ray diffraction pattern of the moist muscle is restored. 3. Stretching of muscle by weights below the breaking point produces an additional well defined diffraction line, corresponding to a spacing of 4.32 A.u. A similar diffraction line can be produced in frog tendon upon stretching. 4. The influence of heat on the x-ray diffraction pattern of muscle depends upon the maximum temperature and the length of action; 5 minutes at 50 degrees C. markedly reduces the orientation of the sample; 5 minutes' immersion in boiling Ringer's solution destroys the orientation and produces a ring corresponding to a spacing of 5.3 to 5.5 A.u. in the moist and sharpening of the backbone reflection in the dried specimen. 5. Ultraviolet light brings forth changes in the x-ray diffraction pattern varying with the intensity of the irradiation. Ultimately a disappearance of the equatorial points and of the outside sickles is achieved while the elliptical shape of the outside ring and its diffuseness persist. In addition two salt rings characteristic of NaCl indicate that the irradiated muscles have become permeable to the surrounding medium (Ringer's solution). 6. Both faradic and single shock electrical stimulation were tried on muscles. If shortening of the muscle is prevented either by sufficient weight or by tying the muscle in a frame, no changes in the x-ray diffraction pattern occur; if the muscle is allowed to shorten without weights or by using insufficient weights, then the orientation either disappears completely or partially. When the muscle is stretched while contracted by electrical stimulation the orientation of the x-ray diffraction pattern reappears. 7. A number of salts with uni- and bivalent ions in concentrations corresponding osmotically to 0.73 per cent NaCl and 10 per cent NH(4)Cl were studied in their effects upon the x-ray diffraction of muscles. Of the salts with univalent ions in the lower concentration only KCl causes a marked decrease of orientation and an increase in the permeability of the fiber membranes. Similar effects on the orientation seem to be produced by CaCl(2) while MgCl(2) causes rather a more pronounced orientation. At hypertonic salt concentrations the orientation disappears completely and the corresponding salt rings become visible. Besides, NaCNS seems to have a specific effect on the outside ring and LiCl produces a ring at 21.3 A.u. and a splitting of the outside ring. 8. Strong mineral and lactic acids in concentrations up to 0.005 N have little if any influence upon the x-ray diffraction of muscles. A further increase in acidity to 0.01 N and above destroys the orientation completely, causes sharpening of the backbone reflection, and increased membrane permeability. These

Spiegel-Adolf, M; Henny, G C; Ashkenaz, E W

1944-11-20

26

An X-ray diffraction study of titanium oxidation  

NASA Technical Reports Server (NTRS)

Titanium specimens of commercial purity were exposed at 1100 to 1400 F to laboratory air for times up to 100 hours. The extent of substrate contamination by interstitial oxygen was was determined by a new X-ray diffraction analysis involving transformation of X-ray diffraction intensity bands. The oxygen solid-solubility at the oxide-metal interfaces and its variation with time at temperature were also determined. Diffusion coefficients are deduced from the oxygen depth profiles.

Wiedemann, K. E.; Unnam, J.

1984-01-01

27

Diffraction effects in x-ray proximity printing  

Microsoft Academic Search

The influence of diffraction on the shape and size of features printed using x-ray proximity printing with a collimated x-ray source (measured beam divergence of approximately 0.2 mrad full width at half-maximum) at mask to wafer gaps of 25 [mu]m and above is described. Three major conclusions can be drawn from the results: (1) Diffraction can distort the shape of

A. D. Dubner; A. Wagner; J. Mauer; J. P. Levin

2009-01-01

28

Transient x-ray diffraction to measure the dynamic response of shocked lithium fluoride single crystal  

NASA Astrophysics Data System (ADS)

Transient x-ray diffraction, also called time-resolved x-ray diffraction and dynamic x-ray diffraction, is one novel diagnostic technique for probing shocked solids. It can provide direct information about microscopic mechanisms governing shock-induced deformation and structural changes at atomistic scales with nanosecond and picoseconds resolution, and lately, it has become possible to measure the structure of transients with sub-picoseconds and sub-Angstrom resolution with the development of ultrafast lasers which can produce femtosecond electron and x-ray pulses in the form of characteristics emission lines as well as x-ray continua in the keV range. In this paper, we detect and measure directly the dynamic response of lithium fluoride single crystal shocked compressed by laser irradiation in SHENGUANG II. In our experiments, high-intensity lasers irradiated a thin Cu foil to generate helium-like rays as x-ray source. Film (IP--image plate) recorded x rays diffracted from multiple lattice planes both perpendicular and oblique angles to the shock loading direction [100]. We gained the diffraction signals of the lattice planes (200) shocked and unshocked, what's more, other lattices (113), (1-13). The positions of the diffraction lines associated with the (200) lattice plane indicated compression of the lattice along [100] direction by 13%. In the experiment, a large-angle detector consists of two films-one rectangular in shape,one triangular in shape that are positioned to record x rays diffracted from a shocked single crystal nearly within a full ? steradian. The experiment shows that transient x-ray diffraction can diagnose the dynamical response of solid with higher resolution.

Wang, Hai-rong; Ye, Yan; Yang, Qing-guo; Li, Mu; Xiao, Sha-li; Li, Ze-ren

2013-08-01

29

Relationship between protein adsorptive capacity and the X-ray diffraction pattern of aluminium hydroxide adjuvants.  

PubMed

Thermal treatment during the preparation of aluminium hydroxide adjuvants affects the primary crystallite size of the adjuvant. The primary crystallite size can be characterized by the line broadening of the (020) reflection of the X-ray diffraction pattern. Studies of protein adsorption using bovine serum albumin as a model protein revealed a direct relationship between the albumin adsorptive capacity and the width at half height (WHH) of the (020) reflection in the X-ray diffraction pattern. PMID:8147102

Masood, H; White, J L; Hem, S L

1994-02-01

30

Cryogenic X-ray Diffraction Microscopy for Biological Samples  

SciTech Connect

X-ray diffraction microscopy (XDM) is well suited for nondestructive, high-resolution biological imaging, especially for thick samples, with the high penetration power of x rays and without limitations imposed by a lens. We developed nonvacuum, cryogenic (cryo-) XDM with hard x rays at 8 keV and report the first frozen-hydrated imaging by XDM. By preserving samples in amorphous ice, the risk of artifacts associated with dehydration or chemical fixation is avoided, ensuring the imaging condition closest to their natural state. The reconstruction shows internal structures of intact D. radiodurans bacteria in their natural contrast.

E Lima; L Wiegart; P Pernot; M Howells; J Timmins; F Zontone; A Madsen

2011-12-31

31

Cryogenic X-Ray Diffraction Microscopy for Biological Samples  

SciTech Connect

X-ray diffraction microscopy (XDM) is well suited for nondestructive, high-resolution biological imaging, especially for thick samples, with the high penetration power of x rays and without limitations imposed by a lens. We developed nonvacuum, cryogenic (cryo-) XDM with hard x rays at 8 keV and report the first frozen-hydrated imaging by XDM. By preserving samples in amorphous ice, the risk of artifacts associated with dehydration or chemical fixation is avoided, ensuring the imaging condition closest to their natural state. The reconstruction shows internal structures of intact D. radiodurans bacteria in their natural contrast.

Lima, Enju; Wiegart, Lutz; Pernot, Petra; Howells, Malcolm; Timmins, Joanna; Zontone, Federico; Madsen, Anders [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble (France)

2009-11-06

32

Three-dimensional x-ray diffraction detection and visualization  

NASA Astrophysics Data System (ADS)

A new method of sensing and analyzing three-dimensional (3D) x-ray diffraction (XRD) cones was introduced. Using a two-dimensional area detector, a sequence of frames was collected while moving the detector away from the sample with small equally spaced steps and keeping all other parameters constant. A 3D dataset was created from the subsequent frames. The 3D x-ray diffraction (XRD3) pattern contains far more information than a one-dimensional profile collected with the conventional diffractometer and 2D x-ray diffraction (XRD2). The present work discusses some fundamentals about XRD3, such as the data collection method, 3D visualization, diffraction data interpretation and potential applications of XRD3.

Allahkarami, Masoud; Hanan, Jay C.

2014-05-01

33

Tutorial on x-ray microLaue diffraction  

SciTech Connect

MicroLaue diffraction combines the oldest x-ray diffraction method-Laue diffraction-with the most modern x-ray sources, optics and detectors. The combination can resolve complex materials into single-crystal-like submicron volumes. This unique ability to nondestructively map crystal structure at and below a sample surface, with high spatial and strain resolution can address long-standing fundamental issues in materials science. For example, the three-dimensional evolution of mesoscale structure and the self organization of defects can be observed nondestructively to understand the origins of inhomogeneous grain growth, deformation and fracture.

Ice, Gene E., E-mail: IceGE@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6118 (United States); Pang, Judy W.L. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6118 (United States)

2009-11-15

34

Tutorial on x-ray microLaue diffraction  

SciTech Connect

MicroLaue diffraction combines the oldest x-ray diffraction method--Laue diffraction--with the most modern x-ray sources, optics and detectors. The combination can resolve complex materials into single-crystal-like submicron volumes. This unique ability to nondestructively map crystal structure at and below a sample surface, with high spatial and strain resolution can address long-standing fundamental issues in materials science. For example, the three-dimensional evolution of mesoscale structure and the self organization of defects can be observed nondestructively to understand the origins of inhomogeneous grain growth, deformation and fracture.

Ice, Gene E [ORNL; Pang, Judy [ORNL

2009-01-01

35

X-Ray Bragg Diffraction in Asymmetric Backscattering Geometry  

Microsoft Academic Search

We observe three effects in the Bragg diffraction of x rays in backscattering geometry from asymmetrically cut crystals. First, exact Bragg backscattering takes place not at normal incidence to the reflecting atomic planes. Second, a well-collimated (â1 μrad) beam is transformed after the Bragg reflection into a strongly divergent beam (230 μrad) with reflection angle dependent on x-ray wavelength--an effect

J. Zhao; A. Alatas; H. D. Rueter; U. Kuetgens; M. Lerche; Yu. V. Shvydko

2006-01-01

36

X-Ray Bragg Diffraction in Asymmetric Backscattering Geometry  

Microsoft Academic Search

We observe three effects in the Bragg diffraction of x rays in backscattering geometry from asymmetrically cut crystals. First, exact Bragg backscattering takes place not at normal incidence to the reflecting atomic planes. Second, a well-collimated (~=1murad) beam is transformed after the Bragg reflection into a strongly divergent beam (230murad) with reflection angle dependent on x-ray wavelength---an effect of angular

Yu. V. Shvyd'Ko; M. Lerche; U. Kuetgens; H. D. Rüter; A. Alatas; J. Zhao

2006-01-01

37

X-Ray Diffraction Wafer Mapping Method for Rhombohedral Super-Hetero-Epitaxy  

NASA Technical Reports Server (NTRS)

A new X-ray diffraction (XRD) method is provided to acquire XY mapping of the distribution of single crystals, poly-crystals, and twin defects across an entire wafer of rhombohedral super-hetero-epitaxial semiconductor material. In one embodiment, the method is performed with a point or line X-ray source with an X-ray incidence angle approximating a normal angle close to 90 deg, and in which the beam mask is preferably replaced with a crossed slit. While the wafer moves in the X and Y direction, a narrowly defined X-ray source illuminates the sample and the diffracted X-ray beam is monitored by the detector at a predefined angle. Preferably, the untilted, asymmetric scans are of {440} peaks, for twin defect characterization.

Park, Yoonjoon; Choi, Sang Hyouk; King, Glen C.; Elliott, James R.; Dimarcantonio, Albert L.

2010-01-01

38

Real-time x-ray diffraction measurements of shocked polycrystalline tin and aluminum  

Microsoft Academic Search

A new, fast, single-pulse x-ray diffraction (XRD) diagnostic for determining phase transitions in shocked polycrystalline materials has been developed. The diagnostic consists of a 37-stage Marx bank high-voltage pulse generator coupled to a needle-and-washer electron beam diode via coaxial cable, producing line and bremsstrahlung x-ray emission in a 35 ns pulse. The characteristic Kalpha lines from the selected anodes of

Dane V. Morgan; Don Macy; Gerald Stevens

2008-01-01

39

Towards high-resolution ptychographic x-ray diffraction microscopy  

SciTech Connect

Ptychographic x-ray diffraction microscopy is a lensless imaging technique with a large field of view and high spatial resolution, which is also useful for characterizing the wavefront of an x-ray probe. The performance of this technique is degraded by positioning errors due to the drift between the sample and illumination optics. We propose an experimental approach for correcting the positioning errors and demonstrate success by two-dimensionally reconstructing both the wavefront of the focused x-ray beam and the complex transmissivity of the weakly scattering objects at the pixel resolution of better than 10 nm in the field of view larger than 5 {mu}m. This method is applicable to not only the observation of organelles inside cells or nano-mesoscale structures buried within bulk materials but also the characterization of probe for single-shot imaging with x-ray free electron lasers.

Takahashi, Yukio; Suzuki, Akihiro; Yamauchi, Kazuto [Graduate School of Engineering, Osaka University, 2-1 Yamada oka, Suita, Osaka 565-0871 (Japan); Zettsu, Nobuyuki [Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University, Furocho, Chikusa-ku, Nagoya 4648603 (Japan); Kohmura, Yoshiki; Ishikawa, Tetsuya [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo, Hyogo 679-5148 (Japan); Senba, Yasunori; Ohashi, Haruhiko [Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo, Hyogo 679-5198 (Japan)

2011-06-01

40

X-Ray-Diffraction Tests Of Irradiated Electronic Devices: I  

NASA Technical Reports Server (NTRS)

X-ray-diffraction tests performed on aluminum conductors in commercial HI1-507A complementary metal oxide/semiconductor (CMOS) integrated-circuit analog multiplexers, both before and after circuits exposed to ionizing radiation from Co(60) source, and after postirradiation annealing at ambient and elevated temperatures. Tests in addition to electrical tests performed to determine effects of irradiation and of postirradiation annealing on electrical operating characteristics of circuits. Investigators sought to determine whether relationship between effects of irradiation on devices and physical stresses within devices. X-ray diffraction potentially useful for nondestructive measurement of stresses.

Shaw, David C.; Lowry, Lynn E.; Barnes, Charles E.

1993-01-01

41

Remote X-Ray Diffraction and X-Ray Fluorescence Analysis on Planetary Surfaces  

NASA Technical Reports Server (NTRS)

The legacy of planetary X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) began in 1960 when W. Parish proposed an XRD instrument for deployment on the moon. The instrument was built and flight qualified, but the Lunar XRD program was cancelled shortly before the first human landing in 1969. XRF chemical data have been collected in situ by surface landers on Mars (Viking 1 & 2, Pathfinder) and Venus (Venera 13 & 14). These highly successful experiments provide critical constraints on our current understanding of surface processes and planetary evolution. However, the mineralogy, which is more critical to planetary surface science than simple chemical analysis, will remain unknown or will at best be imprecisely constrained until X-ray diffraction (XRD) data are collected. Recent progress in X-ray detector technology allows the consideration of simultaneous XRD (mineralogic analysis) and high-precision XRF (elemental analysis) in systems miniaturized to the point where they can be mounted on fixed landers or small robotic rovers. There is a variety of potential targets for XRD/XRF equipped landers within the solar system, the most compelling of which are the poles of the moon, the southern highlands of Mars and Europa.

Blake, David F.; DeVincenzi, D. (Technical Monitor)

1999-01-01

42

X-ray diffraction tomography employing an annular beam.  

PubMed

We demonstrate depth-resolved materials characterization by scanning a sample through an annular beam of X-rays. We measure Bragg X-ray diffraction from a sample with a planar detector positioned centrally in a circular dark field defined by the annular beam. The diffraction maxima are optically encoded with the position of crystalline phases along this beam. Depth-resolved material phase images are recovered via tomosynthesis. We demonstrate our technique using a heterogeneous three-dimensional object comprising three different phases; cyclotetramethylene - tetranitramine, copper and nickel, distributed in a low density medium. Our technique has wide applicability in analytical imaging and is scalable with respect to both scan size and X-ray energy. PMID:24921314

Evans, Paul; Rogers, Keith; Dicken, Anthony; Godber, Simon; Prokopiou, Danae

2014-05-19

43

High-Energy Diffraction-Enhanced X-ray Imaging  

SciTech Connect

In order to apply the diffraction-enhanced X-ray imaging (DEI) method for much wider variety of samples, we have developed the high-energy DEI system. The energy of X-ray was increased up to 70 keV to achieve high permeability for heavy elements. The diffraction of Si(440) was used to keep large field of view. Demonstrative observation of an electrical cable was performed using the X-ray emitted from the vertical wiggler. The obtained images visualized not only the core and ground wire made of copper but also the isolator and outer jacket made of polymer clearly. The comparison of images obtained by the DEI and the absorption-contrast imaging showed that the sensitivity of DEI is about 10 times higher than that of the absorption method for light elements, and 3 times for heavy elements.

Yoneyama, Akio; Ueda, Kazuhiro [Advanced Research Laboratory, Hitachi Ltd., 2520, Akanuma, Hatoyama, Saitama, 350-0395 (Japan); Takeda, Tohoru [Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa 228-8555 (Japan); Yamazaki, Takanori [Research and Development Laboratory, Hitachi Cable, Ltd., 5-1-1, Hidakacho, Hitachi, Ibaraki, 319-1414 (Japan); Hyodo, Kazuyuki [Institute of Materials Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801 (Japan)

2010-06-23

44

The Lang method of X-ray diffraction topography  

Microsoft Academic Search

The paper sets forth the basic principles of the Lang method of X-ray diffraction topography for the investigation of imperfections in crystals. Main Techniques for its experimental implementation are described, and relations and procedures used in the interpretation of the topograms are examined. The problem of resolution is analyzed along with the main factors determining contrast at dislocations. Some of

R. Fiedler; M. Polcarova

1975-01-01

45

Coherent X-ray diffraction from collagenous soft tissues  

SciTech Connect

Coherent X-ray diffraction has been applied in the imaging of inorganic materials with great success. However, its application to biological specimens has been limited to some notable exceptions, due to the induced radiation damage and the extended nature of biological samples, the last limiting the application of most part of the phasing algorithms. X-ray ptychography, still under development, is a good candidate to overcome such difficulties and become a powerful imaging method for biology. We describe herein the feasibility of applying ptychography to the imaging of biological specimens, in particular collagen rich samples. We report here speckles in diffraction patterns from soft animal tissue, obtained with an optimized small angle X-ray setup that exploits the natural coherence of the beam. By phasing these patterns, dark field images of collagen within tendon, skin, bone, or cornea will eventually be obtained with a resolution of 60-70 nm. We present simulations of the contrast mechanism in collagen based on atomic force microscope images of the samples. Simulations confirmed the 'speckled' nature of the obtained diffraction patterns. Once inverted, the patterns will show the disposition and orientation of the fibers within the tissue, by enhancing the phase contrast between protein and no protein regions of the sample. Our work affords the application of the most innovative coherent X-ray diffraction tools to the study of biological specimens, and this approach will have a significant impact in biology and medicine because it overcomes many of the limits of current microscopy techniques.

Berenguer de la Cuesta, Felisa; Wenger, Marco P.E.; Bean, Richard J.; Bozec, Laurent; Horton, Michael A.; Robinson, Ian K.; (UCL)

2009-09-11

46

A Practical Method of Simulating X-Ray Diffraction  

ERIC Educational Resources Information Center

Describes an experiment in which the beam of X-rays is simulated through the use of a laser as a monochromatic light source and the crystal is replaced by photographically prepared masks. A strong diffraction pattern as large as 20 cm. can be obtained. (GS)

Brisse, F.; Sundararajan, P. R.

1975-01-01

47

Single photon energy dispersive x-ray diffraction.  

PubMed

With the pressure range accessible to laser driven compression experiments on solid material rising rapidly, new challenges in the diagnosis of samples in harsh laser environments are emerging. When driving to TPa pressures (conditions highly relevant to planetary interiors), traditional x-ray diffraction techniques are plagued by increased sources of background and noise, as well as a potential reduction in signal. In this paper we present a new diffraction diagnostic designed to record x-ray diffraction in low signal-to-noise environments. By utilising single photon counting techniques we demonstrate the ability to record diffraction patterns on nanosecond timescales, and subsequently separate, photon-by-photon, signal from background. In doing this, we mitigate many of the issues surrounding the use of high intensity lasers to drive samples to extremes of pressure, allowing for structural information to be obtained in a regime which is currently largely unexplored. PMID:24689599

Higginbotham, Andrew; Patel, Shamim; Hawreliak, James A; Ciricosta, Orlando; Collins, Gilbert W; Coppari, Federica; Eggert, Jon H; Suggit, Matthew J; Tang, Henry; Wark, Justin S

2014-03-01

48

Sputtering deposition, XPS and X-ray diffraction characterization of hard nitrogen-platinum thin films  

Microsoft Academic Search

Nitrogen-platinum thin films have been prepared by reactive sputtering. The surface and the bulk of these films for which nitrogen incorporation promotes adherence and hardness, have been investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), nuclear analysis and electrical measurements. The XPS data (core lines and conduction band) support the existence of a PtNx compound (x of the order

A. Hecq; J. P. Delrue; M. Hecq; T. Robert

1981-01-01

49

Resonance energy shifts during nuclear Bragg diffraction of x rays  

SciTech Connect

We have observed dramatic changes in the time distribution of synchrotron x rays resonantly scattered from {sup 57}Fe nuclei in a crystal of yttrium iron garnet, which depend on the deviation angle of the incident radiation from the Bragg angle. These changes are caused by small shifts in the effective energies of the hyperfine-split nuclear resonances, an effect of dynamical diffraction for the coherently excited nuclei in the crystal. The very high brightness of the synchro- tron x-ray source allows this effect to be observed in a 15-min measurement.

Arthur, J.; Brown, G.S.; Brown, D.E.; Ruby, S.L. (Stanford Synchrotron Radiation Laboratory, Post Office Box 4349, Bin 69, Stanford, California 94309 (US))

1989-10-09

50

Minerals Arranged by X-Ray Powder Diffraction  

NSDL National Science Digital Library

This directory provides a listing of minerals arranged by Powder X-ray Diffraction (XRD) data . XRD is one of the primary techniques used to examine the physico-chemical make-up of unknown solids, in which a powdered sample is illuminated with X rays of a fixed wavelength and the intensity of the reflected radiation is recorded using a goniometer. Minerals are arranged in increasing order of D1 spacing, with D2 and D3 spacings also provided. Each mineral name is a link to additional information on the mineral.

51

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

52

Wavefront aberrations of x-ray dynamical diffraction beams.  

PubMed

The effects of dynamical diffraction in x-ray diffractive optics with large numerical aperture render the wavefront aberrations difficult to describe using the aberration polynomials, yet knowledge of them plays an important role in a vast variety of scientific problems ranging from optical testing to adaptive optics. Although the diffraction theory of optical aberrations was established decades ago, its application in the area of x-ray dynamical diffraction theory (DDT) is still lacking. Here, we conduct a theoretical study on the aberration properties of x-ray dynamical diffraction beams. By treating the modulus of the complex envelope as the amplitude weight function in the orthogonalization procedure, we generalize the nonrecursive matrix method for the determination of orthonormal aberration polynomials, wherein Zernike DDT and Legendre DDT polynomials are proposed. As an example, we investigate the aberration evolution inside a tilted multilayer Laue lens. The corresponding Legendre DDT polynomials are obtained numerically, which represent balanced aberrations yielding minimum variance of the classical aberrations of an anamorphic optical system. The balancing of classical aberrations and their standard deviations are discussed. We also present the Strehl ratio of the primary and secondary balanced aberrations. PMID:25322219

Liao, Keliang; Hong, Youli; Sheng, Weifan

2014-10-01

53

X-ray Diffraction from Membrane Protein Nanocrystals  

PubMed Central

Membrane proteins constitute >30% of the proteins in an average cell, and yet the number of currently known structures of unique membrane proteins is <300. To develop new concepts for membrane protein structure determination, we have explored the serial nanocrystallography method, in which fully hydrated protein nanocrystals are delivered to an x-ray beam within a liquid jet at room temperature. As a model system, we have collected x-ray powder diffraction data from the integral membrane protein Photosystem I, which consists of 36 subunits and 381 cofactors. Data were collected from crystals ranging in size from 100 nm to 2 ?m. The results demonstrate that there are membrane protein crystals that contain <100 unit cells (200 total molecules) and that 3D crystals of membrane proteins, which contain <200 molecules, may be suitable for structural investigation. Serial nanocrystallography overcomes the problem of x-ray damage, which is currently one of the major limitations for x-ray structure determination of small crystals. By combining serial nanocrystallography with x-ray free-electron laser sources in the future, it may be possible to produce molecular-resolution electron-density maps using membrane protein crystals that contain only a few hundred or thousand unit cells. PMID:21190672

Hunter, M.S.; DePonte, D.P.; Shapiro, D.A.; Kirian, R.A.; Wang, X.; Starodub, D.; Marchesini, S.; Weierstall, U.; Doak, R.B.; Spence, J.C.H.; Fromme, P.

2011-01-01

54

X-ray diffraction from intact tau aggregates in human brain tissue  

SciTech Connect

We describe an instrument to record X-ray diffraction patterns from diseased regions of human brain tissue by combining an in-line visible light fluorescence microscope with an X-ray diffraction microprobe. We use thiazine red fluorescence to specifically label and detect the filamentous tau protein pathology associated with Pick's disease, as several laboratories have done previously. We demonstrate that thiazine red-enhanced regions within the tissue show periodic structure in X-ray diffraction, which is not observed in healthy tissue. One observed periodicity (4.2 {angstrom}) is characteristic of cross-beta sheet structure, consistent with previous results from powder diffraction studies performed on purified, dried tau protein.

Landahl, Eric C.; Antipova, Olga; Bongaarts, Angela; Barrea, Raul; Berry, Robert; Binder, Lester I.; Irving, Thomas; Orgel, Joseph; Vana, Laurel; Rice, Sarah E. (DePaul); (IIT); (NWU)

2011-09-15

55

Anomalous X-ray diffraction with soft X-ray synchrotron radiation.  

PubMed

Anomalous diffraction with soft X-ray synchrotron radiation opens new possibilities in protein crystallography and materials science. Low-Z elements like silicon, phosphorus, sulfur and chlorine become accessible as new labels in structural studies. Some of the heavy elements like uranium exhibit an unusually strong dispersion at their M(V) absorption edge (lambdaMV = 3.497 A, E(MV) = 3545 eV) and so does thorium. Two different test experiments are reported here showing the feasibility of anomalous X-ray diffraction at long wavelengths with a protein containing uranium and with a salt containing chlorine atoms. With 110 electrons the anomalous scattering amplitude of uranium exceeds by a factor of 4 the resonance scattering of other strong anomalous scatterers like that of the lanthanides at their L(III) edge. The resulting exceptional phasing power of uranium is most attractive in protein crystallography using the multi-wavelength anomalous diffraction (MAD) method. The anomalous dispersion of an uranium derivative of asparaginyl-tRNA synthetase (hexagonal unit cell; a = 123.4 A, c = 124.4 A) has been measured for the first time at 4 wavelengths near the M(V) edge using the beamline ID1 of ESRF (Grenoble, France). The present set up allowed to measure only 30% of the possible reflections at a resolution of 4 A, mainly because of the low sensitivity of the CCD detector. In the second experiment, the dispersion of the intensity of 5 X-ray diffraction peaks from pentakismethylammonium undecachlorodibismuthate (PMACB, orthorhombic unit cell; a = 13.003 A, b = 14.038 A, c = 15.450 A) has been measured at 30 wavelengths near the K absorption edge of chlorine (lambdaK = 4.397 A, EK= 2819.6 eV). All reflections within the resolution range from 6.4 A to 3.4 A expected in the 20 degree scan were observed. The chemical state varies between different chlorine atoms of PMACB, and so does the dispersion of different Bragg peaks near the K-edge of chlorine. The results reflect the performance of the beamline ID1 of ESRF at wavelengths beyond 3 A at the end of 1998. A gain by a factor 100 for diffraction experiments with 4.4 A photons was achieved in Autumn 1999 when two focusing mirrors had been added to the X-ray optics. Further progress is expected from area detectors more sensitive to soft X-rays. Both CCD detectors and image plates would provide a gain of two orders of measured intensity. Image plates would have the additional advantage that they can be bent cylindrically and thus cover a larger solid angle in reciprocal space. In many cases, samples need to be cooled: closed and open systems are presented. A comparison with the state of art of soft X-ray diffraction, as it had been reached at HASYLAB (Hamburg, Germany), and as it is developing at the Brookhaven National Laboratory (USA), is given. PMID:10976874

Carpentier, P; Berthet-Colominas, C; Capitan, M; Chesne, M L; Fanchon, E; Lequien, S; Stuhrmann, H; Thiaudière, D; Vicat, J; Zielinski, P; Kahn, R

2000-07-01

56

X-ray diffraction topography image materials by molecular probe  

Microsoft Academic Search

Crystallinity, composition, homogeneity and anisotropy determine the mechanical properties of materials significantly, but the performance of most non-destructive techniques is too poor for measuring these micro structures as they are optimized for finding individual flaws\\/defects. X-ray (wide angle) Diffraction Topography by single beam scanning images molecular information at a spatial resolution of several ten micrometers even in three dimensions. Especially

Manfred P. Hentschel; Axel Lange; Joerg Schors; Oliver Wald

2005-01-01

57

X-ray fluorescence holography: Going beyond the diffraction limit  

Microsoft Academic Search

X-ray fluorescence holography (XFH) is a method for obtaining diffraction-limited images of the local atomic structure around a given type of emitter. The reconstructed wave field represents a distorted image of the scatterer electron-density distribution, i.e., it is a convolution of the charge-density distribution with a point spread function characteristic of the measurement. We here consider several methods for the

S. Marchesini; C. S. Fadley; F. J. Garcia de Abajo

2003-01-01

58

The use of synchrotron radiation in time-resolved X-ray diffraction studies of myosin layer-line reflections during muscle contraction  

NASA Astrophysics Data System (ADS)

Experiments on striated muscle have been carried out at the EMBL Outstation at DESY, Hamburg, using the electron-positron storage ring DORIS as a high-intensity X-ray source. The low-angle reflections from the myosin cross-bridges could be recorded more than 1,000 times more rapidly than with the best conventional X-ray sources, and could be followed during contraction with a time resolution of 10 ms.

Huxley, H. E.; Faruqi, A. R.; Bordas, J.; Koch, M. H. J.; Milch, J. R.

1980-03-01

59

Coherent x-ray diffraction from quantum dots  

SciTech Connect

Coherent x-ray diffraction is a new experimental method for studying perfect and imperfect crystals. Instead of incoherent averaging, a coherent sum of amplitudes produces a coherent diffraction pattern originating from the real space arrangement of the sample. We applied this method for studying quantum dot samples that were specially fabricated GeSi islands of nanometer size and in a regular array embedded into a Si substrate. A coherent beam was focused by special Kirkpatric-Baez optics to a micrometer size. In the experiment it was observed that such a microfocused coherent beam produced coherent diffraction pattern with Bragg spots and broad diffuse maxima. The diffuse peak breaks up into a fine speckle pattern. The grazing incidence diffraction pattern has a typical shape resulting from the periodic array of identical islands. We used this diffraction pattern to reconstruct the average shape of the islands using a model independent approach.

Vartanyants, I.A. [HASYLAB, DESY, Notkestr. 85, Hamburg D-22607 (Germany); Department of Physics, University of Illinois, 1110 W. Green St., Urbana, Illinois 61801 (United States); Robinson, I. K.; Onken, J.D.; Pfeifer, M.A.; Williams, G.J. [Department of Physics, University of Illinois, 1110 W. Green St., Urbana, Illinois 61801 (United States); Pfeiffer, F. [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Metzger, H. [ESRF, BP 220, 38043 Grenoble (France); Zhong, Z. [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Insitut fuer Hableiter-und Festkoeperphysik, Johannes Kepler Universitaet Linz, A-4040 Linz (Austria); Bauer, G. [Insitut fuer Hableiter-und Festkoeperphysik, Johannes Kepler Universitaet Linz, A-4040 Linz (Austria)

2005-06-15

60

Fabricating Blazed Diffraction Gratings by X-Ray Lithography  

NASA Technical Reports Server (NTRS)

Gray-scale x-ray lithography is undergoing development as a technique for fabricating blazed diffraction gratings. As such, gray-scale x-ray lithography now complements such other grating-fabrication techniques as mechanical ruling, holography, ion etching, laser ablation, laser writing, and electron-beam lithography. Each of these techniques offers advantages and disadvantages for implementing specific grating designs; no single one of these techniques can satisfy the design requirements for all applications. Gray-scale x-ray lithography is expected to be advantageous for making gratings on steeper substrates than those that can be made by electron-beam lithography. This technique is not limited to sawtooth groove profiles and flat substrates: various groove profiles can be generated on arbitrarily shaped (including highly curved) substrates with the same ease as sawtooth profiles can be generated on flat substrates. Moreover, the gratings fabricated by this technique can be made free of ghosts (spurious diffraction components attributable to small spurious periodicities in the locations of grooves). The first step in gray-scale x-ray lithography is to conformally coat a substrate with a suitable photoresist. An x-ray mask (see Figure 1) is generated, placed between the substrate and a source of collimated x-rays, and scanned over the substrate so as to create a spatial modulation in the exposure of the photoresist. Development of the exposed photoresist results in a surface corrugation that corresponds to the spatial modulation and that defines the grating surface. The grating pattern is generated by scanning an appropriately shaped x-ray area mask along the substrate. The mask example of Figure 1 would generate a blazed grating profile when scanned in the perpendicular direction at constant speed, assuming the photoresist responds linearly to incident radiation. If the resist response is nonlinear, then the mask shape can be modified to account for the nonlinearity and produce a desired groove profile. An example of grating grooves generated by this technique is shown in Figure 2. A maximum relative efficiency of 88 percent has been demonstrated.

Mouroulis, Pantazis; Hartley, Frank; Wilson, Daniel

2004-01-01

61

Synchrotron x-ray powder diffraction studies in pulsed magnetic fields  

SciTech Connect

X-ray powder diffraction experiments under pulsed magnetic fields were carried out at the DUBBLE beamline (BM26B) at the ESRF. A mobile generator delivered 110 kJ to the magnet coil, which was sufficient to generate peak fields of 30 T. A liquid He flow cryostat allowed us to vary the sample temperature accurately between 8 and 300 K. Powder diffraction patterns of several samples were recorded using 21 keV monochromatic x-rays and an on-line image plate detector. Here we present the first results on the suppression of the Jahn-Teller structural distortion in TbVO{sub 4} by magnetic field. These data clearly demonstrate the feasibility of x-ray powder diffraction experiments under pulsed magnetic fields with relatively inexpensive instrumentation.

Frings, P.; Vanacken, J.; Detlefs, C.; Duc, F.; Lorenzo, J. E.; Nardone, M.; Billette, J.; Zitouni, A.; Bras, W.; Rikken, G. L. J. A. [Laboratoire National des Champs Magnetiques Pulses, 143, Avenue de Rangueil, F-31400 Toulouse (France); Laboratoire National des Champs Magnetiques Pulses, 143, Avenue de Rangueil, F-31400 Toulouse, France and Pulsveldengroep, Institute for Nanoscale Physics and Chemistry, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Laboratoire National des Champs Magnetiques Pulses, 143, Avenue de Rangueil, F-31400 Toulouse, France and European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble (France); Centre d'Elaboration de Materiaux et d'Etudes Structurales, CNRS, B.P. 94347, F-31055 Toulouse (France); Laboratoire de Cristallographie, CNRS, B.P. 166X, F-38043 Grenoble (France); Laboratoire National des Champs Magnetiques Pulses, 143, Avenue de Rangueil, F-31400 Toulouse (France); Netherlands Organisation for Scientific Research (NWO), DUBBLE CRG-ESRF, B.P. 220, F-38043 Grenoble (France); Laboratoire National des Champs Magnetiques Pulses, 143, Avenue de Rangueil, F-31400 Toulouse (France)

2006-06-15

62

Borman effect in resonant diffraction of X-rays  

SciTech Connect

A dynamic theory of resonant diffraction (occurring when the energy of incident radiation is close to the energy of the absorption edge of an element in the composition of a given substance) of synchronous X-rays is developed in the two-wave approximation in the coplanar Laue geometry for large grazing angles in perfect crystals. A sharp decrease in the absorption coefficient in the substance with simultaneously satisfied diffraction conditions (Borman effect) is demonstrated, and the theoretical and first experimental results are compared. The calculations reveal the possibility of applying this approach in analyzing the quadrupole-quadrupole contribution to the absorption coefficient.

Oreshko, A. P., E-mail: ap.oreshko@physics.msu.ru [Moscow State University (Russian Federation)

2013-08-15

63

Line-Source Based X-Ray Tomography  

PubMed Central

Current computed tomography (CT) scanners, including micro-CT scanners, utilize a point x-ray source. As we target higher and higher spatial resolutions, the reduced x-ray focal spot size limits the temporal and contrast resolutions achievable. To overcome this limitation, in this paper we propose to use a line-shaped x-ray source so that many more photons can be generated, given a data acquisition interval. In reference to the simultaneous algebraic reconstruction technique (SART) algorithm for image reconstruction from projection data generated by an x-ray point source, here we develop a generalized SART algorithm for image reconstruction from projection data generated by an x-ray line source. Our numerical simulation results demonstrate the feasibility of our novel line-source based x-ray CT approach and the proposed generalized SART algorithm. PMID:19436708

Bharkhada, Deepak; Yu, Hengyong; Liu, Hong; Plemmons, Robert; Wang, Ge

2009-01-01

64

A system for x-ray diffraction and fluorescence imaging of nanoparticle biomarkers  

Microsoft Academic Search

Both x-ray diffraction and x-ray fluorescence techniques have proven beneficial for identifying and characterizing biological tissues. X-ray diffraction analysis uses the elemental composition of the sample to discriminate between tissue types, and can provide a considerable enhancement in contrast over conventional x-ray imaging. X-ray fluorescence, in this case, is being used to locate the presence of nanoparticles, such as gold,

Kate Pepper; Christiana Christodoulou; Chiara Guazzoni; Andrea Castoldi; Cigdem Ozkan; Nicola Sodini; Diego Dreossi; Jennifer A. Griffiths; Adam P. Gibson; Gary J. Royle

2010-01-01

65

Lattice Misfit Measurement in Inconel 625 BY X-Ray Diffraction Technique  

Microsoft Academic Search

Determination of lattice misfit and microstructural parameters of the coherent precipitates in Ni based alloy Inconel-625 is a challenging problem as the diffraction peaks of the precipitate and the matrix are completely overlapping. X-ray Diffraction Line Profile Analysis (XRDLPA) has been used to characterize the bulk samples of Inconel 625 at different heat-treated conditions to determine the lattice parameters of

A. Sarkar; P. Mukherjee; P. Barat; T. Jayakumar; S. Mahadevan; Sanjay K. Rai

2008-01-01

66

ISOCAM Photometry of Narrow-Line X-ray Galaxies  

E-print Network

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

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

1998-12-23

67

Counting Dislocations in Microcrystals by Coherent X-Ray Diffraction  

NASA Astrophysics Data System (ADS)

We present here an unprecedented way of quantifying the number of dislocations in microcrystals. This method relies on a combination of several state-of-the-art techniques: coherent x-ray diffraction used as a local probe, together with the controlled compression of micro-objects. We demonstrate that by using this method, dislocations in the microcrystal can be detected and their number precisely quantified. This cannot be done with other techniques in a nondestructive way. Our method opens a route for the study of many small-scale systems with defect-dependent physical properties and it could become a critical tool for addressing future challenges in nanotechnology.

Jacques, V. L. R.; Carbone, D.; Ghisleni, R.; Thilly, L.

2013-08-01

68

The three dimensional X-ray diffraction technique  

SciTech Connect

This introductory tutorial describes the so called 3 dimensional X-ray diffraction (3DXRD) technique, which allows bulk non-destructive structural characterizations of crystalline materials. The motivations and history behind the development of this technique are described and its potentials are sketched. Examples of the use of the technique are given and future trends and developments are suggested. The primary aim of the paper is to give 3DXRD novices an easy introduction to the technique and to describe a way from a dream to reality and new results.

Jensen, D. Juul, E-mail: doje@dtu.dk [Danish Chinese Center for Nanometals, Materials Science and Advanced Characterization Section, Department of Wind Energy, Technical University of Denmark, Riso Campus (Denmark); Poulsen, H.F. [Department of Physics, Technical University of Denmark, Lyngby Campus (Denmark)] [Department of Physics, Technical University of Denmark, Lyngby Campus (Denmark)

2012-10-15

69

Multicrystal X-ray diffraction of heteroepitaxial structures  

NASA Astrophysics Data System (ADS)

An appraisal of high-resolution multi-crystal multi-reflection diffractometry (HRMCMRD) and topography is presented to illustrate its potential for structure analysis. Examples of methods for extracting lateral interface roughness, studying layered structures with imperfect epitaxy (including strained layer structures) are given to show the wealth of information available from X-ray techniques. The advantages of diffraction space mapping are discussed in addition to the use of topography to interpret the diffuse and Bragg scattering. The HRMCMRD has a dynamic range of 10 6 and can record topographs with intensities less than 1 count/s.

Fewster, Paul F.

1991-06-01

70

X-ray diffraction studies of shocked lunar analogs  

NASA Technical Reports Server (NTRS)

The X-ray diffraction experiments on shocked rock and mineral analogs of particular significance to lunar geology are described. Materials naturally shocked by meteorite impact, nuclear-shocked, or artificially shocked in a flat plate accelerator were utilized. Four areas were outlined for investigation: powder diffractometer studies of shocked single crystal silicate minerals (quartz, orthoclase, oligoclase, pyroxene), powder diffractometer studies of shocked polycrystalline monomineralic samples (dunite), Debye-Scherrer studies of single grains of shocked granodiorite, and powder diffractometer studies of shocked whole rock samples. Quantitative interpretation of peak shock pressures experienced by materials found in lunar or terrestrial impact structures is presented.

Hanss, R. E.

1979-01-01

71

Anomalous X-ray Diffraction Studies for Photovoltaic Applications  

SciTech Connect

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

2011-06-22

72

CCMR: X-Ray Diffraction Studies of Pulsed Laser Deposition  

NSDL National Science Digital Library

Pulsed laser deposition is an extremely effective method of growing thin films of materials on substrates. In this particular experiment the deposition of various pervoskite molecules onto different substrates were monitored via x-ray diffraction from a synchrotron source. Molecular compounds that were chosen were CaTiO3, SrTiO3, and BaTiO3 due to there structural similarities and correspondingly different lattice constants. The lattice constants for CaTiO3, SrTiO3, and BaTiO3 are 3.80, 3.90, and 4.06 respectively. These materials all have the same valence structure. Based upon the intensities of the diffracted x-rays at the anti-Bragg peak position, the growth of the film was monitored on a monolayer by monolayer scale at 750°C. The film quality of CaTiO3 on SrTiO3 and BaTiO3 on SrTiO3 were compared to a homoepitaxial film of SrTiO3 to determine how the strain at the interface affected growth. It was determined that the tensilely strain film, CaTiO3, grew more smoothly than the ompressively strained material BaTiO3.

Ferguson, John

2004-08-17

73

Diffraction and holography of photoelectrons and fluorescent x-rays  

SciTech Connect

Photoelectron diffraction is by now a powerful technique for studying surface structures, with special capabilities for resolving chemical and magnetic states of atoms and deriving direct structural information from both forward scattering and backscattering. Fitting experiment to theory can lead to structural accuracies in the 0.03 {Angstrom} range. Holographic inversions of such diffraction data also show considerable promise for deriving local three-dimensional structures around a given emitter with accuracies of 0.2--0.3 {Angstrom}. Resolving the photoelectron spin in some way and using circularly polarized radiation for excitation provide added dimensions for the study of magnetic systems and chiral experimental geometries. Synchrotron radiation with the highest brightness and energy resolution, as well as variable polarization, is crucial to the full exploitation of these techniques. X-ray fluorescence holography also has promise for structural studies, but will require intense excitation sources and multichannel detection to be feasible.

Fadley, C.S. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Davis, CA (United States). Dept. of Physics

1993-04-01

74

Femtosecond diffractive imaging with a soft-X-ray free-electron laser  

E-print Network

LETTERS Femtosecond diffractive imaging with a soft-X-ray free-electron laser HENRY N. CHAPMAN1 of this principle using the FLASH soft-X-ray free-electron laser. An intense 25 fs, 4 Ã? 1013 W cm-2 pulse by one10 . X-ray free-electron lasers (FELs) are expected to permit diffractive imaging at high

Loss, Daniel

75

Structural characterization of Au\\/Co multilayers by x-ray diffraction, x-ray reflectivity and glancing-incidence x-ray fluorescence  

Microsoft Academic Search

The magnetic properties of metallic multilayers are strongly influenced by their structural properties, for example interface quality, parallelism of the atomic layers, the amount of strain in the material and the coherence over long distances. In this paper we discuss analysis of such materials in a non-destructive way by the use of glancing-incidence X-ray analysis (GIXA) and high-angle X-ray diffraction.

W. W. v. D. Hoogenhof; T. W. Ryan

1993-01-01

76

IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 1 Coherent X-ray Diffraction Imaging  

E-print Network

and X-ray free-electron lasers are presently under rapid development worldwide, coherent diffraction, oversampling, phase retrieval, X-ray free-electron lasers (XFEL). I. INTRODUCTION MICROSCOPY has found broad

Miao, Jianwei "John"

77

Characterization of X-Ray Diffraction System with a Microfocus X-Ray Source and a Polycapillary Optic  

NASA Technical Reports Server (NTRS)

We present here an optimized microfocus x-ray source and polycapillary optic system designed for diffraction of small protein crystals. The x-ray beam is formed by a 5.5mm focal length capillary collimator coupled with a 40 micron x-ray source operating at 46Watts. Measurements of the x-ray flux, the divergence and the spectral characteristics of the beam are presented, This optimized system provides a seven fold greater flux than our recently reported configuration [M. Gubarev, et al., J. of Applied Crystallography (2000) 33, in press]. We now make a comparison with a 5kWatts rotating anode generator (Rigaku) coupled with confocal multilayer focusing mirrors (Osmic, CMF12- 38Cu6). The microfocus x-ray source and polycapillary collimator system delivers 60% of the x-ray flux from the rotating anode system. Additional ways to improve our microfocus x-ray system, and thus increase the x-ray flux will be discussed.

Gubarev, Mikhail; Marshall, Joy K.; Ciszak, Ewa; Ponomarev, Igor

2000-01-01

78

Synchrotron X-ray Powder Diffraction and Absorption Spectroscopy in Pulsed Magnetic Fields with Milliseconds Duration  

SciTech Connect

X-ray Powder Diffraction and X-ray Absorption Spectroscopy experiments (WAS) and X-ray magnetic circular dichroism (XMCD) experiments were carried out at the ESRF DUBBLE beam line (BM26) and at the energy dispersive beam line (ID24), respectively. A mobile pulse generator, developed at the LNCMP, delivered 110kJ to the load coil, which was sufficient to generate peak fields of 30T with a rise time of about 5 ms. A liquid He flow cryostat allowed us to vary the sample temperature accurately between 4.2K and 300K.Powder diffraction patterns of TbVO4 were recorded in a broad temperature range using 21 keV monochromatic X-rays and using an on-line image plate detector. We observed the suppression of the Jahn-Teller structural distortion in TbVO4 due to the high magnetic pulsed field.XAS spectra could be measured and finite XMCD signals, directly proportional to the magnetic moment on the Gd absorber atom, were measured in thin Gd foils. Thanks to its element and orbital selectivity, XMCD proofs to be very useful in probing the magnetic properties and due to the strong brilliance of the synchrotron beam, the signals can be measured even in the ms range.

Vanacken, J. [LNCMP, 143, avenue de Rangueil BP 14245, F31432 Toulouse (France); Pulsveldengroep, INPAC, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Detlefs, C.; Mathon, O.; Dominguez, M.-C. [ESRF, BP 220, F-38043 Grenoble (France); Frings, P.; Duc, F.; Nardone, M.; Billette, J.; Zitouni, A.; Rikken, G. [LNCMP, 143, avenue de Rangueil BP 14245, F31432 Toulouse (France); Lorenzo, J. E. [Laboratoire de Cristallographie, CNRS, B.P.166X, F-38043 Grenoble (France); Herczeg, J.; Moshchalkov, V. V. [Pulsveldengroep, INPAC, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Bras, W. [DUBBLE CRG at ESRF, BP 220, F-38043 Grenoble (France)

2007-03-30

79

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

Microsoft Academic Search

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 composition. The major components observed are amorphous glass, plagioclase of about An50 composition, minor amounts of quartz and other SiO2 polymorphs, as well as ferromagnesian constituents

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

1981-01-01

80

X-ray diffraction diagnostic design for the National Ignition Facility  

NASA Astrophysics Data System (ADS)

This paper describes the design considerations for Target Diffraction In-Situ (TARDIS), an x-ray diffraction diagnostic at the National Ignition Facility. A crystal sample is ramp-compressed to peak pressures between 10 and 30 Mbar and, during a pressure hold period, is probed with quasi-monochromatic x-rays emanating from a backlighter source foil. The crystal spectrography diffraction lines are recorded onto image plates. The crystal sample, filter, and image plates are packaged into one assembly, allowing for accurate and repeatable target to image plate registration. Unconverted laser light impinges upon the device, generating debris, the effects of which have been mitigated. Dimpled blast shields, high strength steel alloy, and high-z tungsten are used to shield and protect the image plates. A tapered opening was designed to provide adequate thickness of shielding materials without blocking the drive beams or x-ray source from reaching the crystal target. The high strength steel unit serves as a mount for the crystal target and x-ray source foil. A tungsten body contains the imaging components. Inside this sub-assembly, there are three image plates: a 160 degree field of view curved plate directly opposite the target opening and two flat plates for the top and bottom. A polycarbonate frame, coated with the appropriate filter material and embedded with registration features for image plate location, is inserted into the diagnostic body. The target assembly is metrologized and then the diagnostic assembly is attached.

Ahmed, Maryum F.; House, Allen; Smith, R. F.; Ayers, Jay; Lamb, Zachary S.; Swift, David W.

2013-09-01

81

CCMR: X-Ray Diffraction of Magnetic Tunnel Junctions  

NSDL National Science Digital Library

We examined CoFeB/MgO/CoFeB magnetic tunnel junctions with X-ray diffraction in order to determine the effects of anneal temperature, MgO growth type, and seed layer structure on electrode and tunnelbarrier crystallinity. For various sample structures and growth methods, we show electrode crystallinity and texturing improving with increasing anneal temperature, while MgO texturing peaks between 350 C and 400 C. We find the amount and texturing of electrode and barrier crystallinity varies widely with the MgO growth method, with electrode crystallization greatest in samples with MgO grown using ebeam evaporation. Finally, we report that for our sample structures, Ta/CuN seed layers promote the highest level of CoFeB electrode texturing.

Huang, Pinshane Y.

2007-08-29

82

Powder X-ray diffraction laboratory, Reston, Virginia  

USGS Publications Warehouse

The powder x-ray diffraction (XRD) laboratory is managed jointly by the Eastern Mineral and Environmental Resources and Eastern Energy Resources Science Centers. Laboratory scientists collaborate on a wide variety of research problems involving other U.S. Geological Survey (USGS) science centers and government agencies, universities, and industry. Capabilities include identification and quantification of crystalline and amorphous phases, and crystallographic and atomic structure analysis for a wide variety of sample media. Customized laboratory procedures and analyses commonly are used to characterize non-routine samples including, but not limited to, organic and inorganic components in petroleum source rocks, ore and mine waste, clay minerals, and glassy phases. Procedures can be adapted to meet a variety of research objectives.

Piatak, Nadine M.; Dulong, Frank T.; Jackson, John C.; Folger, Helen W.

2014-01-01

83

Hard X-ray nanoimaging method using local diffraction from metal wire  

NASA Astrophysics Data System (ADS)

A simple hard X-ray imaging method achieving a high spatial resolution is proposed. Images are obtained by scanning a metal wire through the wave field to be measured and rotating the sample to collect data for back projection calculations; the local diffraction occurring at the edges of the metal wire operates as a narrow line probe. In-line holograms of a test sample were obtained with a spatial resolution of better than 100 nm. The potential high spatial resolution of this method is shown by calculations using diffraction theory.

Takano, Hidekazu; Konishi, Shigeki; Shimomura, Sho; Azuma, Hiroaki; Tsusaka, Yoshiyuki; Kagoshima, Yasushi

2014-01-01

84

Nondestructive evaluation of fatigue damage in aluminum 2024 by x-ray diffraction  

NASA Technical Reports Server (NTRS)

Aluminum alloys are widely used in the automobile and aerospace industries. This is due to their attractive low density-high modulus and low density-high strength characteristics. Unfortunately, cyclic stress-strain deformations alter the microstructure of aluminum alloys when they are placed into service. These structural changes can lead to fatigue damage and ultimately service failure. Since x-ray diffraction analysis is known to be a sensitive nondestructive indicator of structural changes due to deformations, this technique is being used to evaluate changes in the microstructure of cycled aluminum 2024 commercial alloys. Line shapes, widths, and positions in an x-ray diffraction pattern depend on microstructural properties such as grain size, grain orientation, residual stress, microstrain, etc. Changes in the microstructure due to fatigue will appear as changes in the diffraction pattern. One parameter used to characterize a reflection in a diffraction pattern is the full width at half maximum (FWHM). Preliminary x-ray diffraction results on cycled Al 2024 indicate that the (111) and (222) reflections of the matrix phase do not show any variations in the FWHM due to an increase in the fatigue cycles. However, the FWHM of the (200) and (400) reflections of the same phase unexpectedly showed a dramatic decrease. These results can be interpreted as due to the relaxation of some initial nonuniform residual stresses in the matrix phase lattice. Further work is in progress to evaluate the FWHM of the second phase of the cycled alloys.

Ferguson, Milton W.

1994-01-01

85

A new theory for X-ray diffraction  

PubMed Central

This article proposes a new theory of X-ray scattering that has particular relevance to powder diffraction. The underlying concept of this theory is that the scattering from a crystal or crystallite is distributed throughout space: this leads to the effect that enhanced scatter can be observed at the ‘Bragg position’ even if the ‘Bragg condition’ is not satisfied. The scatter from a single crystal or crystallite, in any fixed orientation, has the fascinating property of contributing simultaneously to many ‘Bragg positions’. It also explains why diffraction peaks are obtained from samples with very few crystallites, which cannot be explained with the conventional theory. The intensity ratios for an Si powder sample are predicted with greater accuracy and the temperature factors are more realistic. Another consequence is that this new theory predicts a reliability in the intensity measurements which agrees much more closely with experimental observations compared to conventional theory that is based on ‘Bragg-type’ scatter. The role of dynamical effects (extinction etc.) is discussed and how they are suppressed with diffuse scattering. An alternative explanation for the Lorentz factor is presented that is more general and based on the capture volume in diffraction space. This theory, when applied to the scattering from powders, will evaluate the full scattering profile, including peak widths and the ‘background’. The theory should provide an increased understanding of the reliability of powder diffraction measurements, and may also have wider implications for the analysis of powder diffraction data, by increasing the accuracy of intensities predicted from structural models. PMID:24815975

Fewster, Paul F.

2014-01-01

86

Energy-tunable x-ray diffraction: A tool for depth profiling in polycrystalline materials  

Microsoft Academic Search

We have developed a new variant of depth-sensitive x-ray diffraction technique to study structural parameters in inhomogeneous polycrystalline materials. In this method, diffraction patterns are measured at different x-ray energies which are varied by small steps, and then the depth-resolved structural characteristics are retrieved from the energy-dependent x-ray diffraction data. In the current articles, this approach is applied to extract

E. Zolotoyabko; J. P. Quintana

2002-01-01

87

Eta Carinae: X-ray Line Variations during the 2003 X-ray Minimum, and the Orbit Orientation  

NASA Technical Reports Server (NTRS)

The future evolution of Eta Carinae will be as a supernova (or hypernova) and black hole. The evolution is highly contingent on mass and angular momentum changes and instabilities. The presence of a companion can serve to trigger instabilities and provide pathways for mass and angular momentum exchange loss. X-rays can be used a a key diagnostic tool: x-ray temperatures trace pre-shock wind velocities, periodic x-ray variability traces the orbit, and x-ray line variations traces the flow and orientation of shocked gas. This brief presentation highlights x-ray line variations from the HETG and presents a model of the colliding wind flow.

Corcoran, M. F.; Henley, D.; Hamaguchi, K.; Khibashi, K.; Pittard, J. M.; Stevens, I. R.; Gull, T. R.

2007-01-01

88

Applications of parametric X-rays for X-ray diffraction analysis  

NASA Astrophysics Data System (ADS)

Until now parametric X-rays (PXR) have not had practical applications because of the lack of a modern compact accelerator providing the required beam current and consequently high X-ray photon flux. PXR sources even with the intensities achievable at present may be applied to a number of X-ray reflectometry and diffractometry measurements which are important for the characterization of crystals and multi-layer nanostructures. In the paper we present some proposals for possible PXR applications for a number of X-ray measurements based on the smooth energy tuning, high monochromaticity and directed emission of this radiation. The theoretical background and numerical evaluations for PXR applications for determining ingredient concentration in a solid solution in the range of anomalous dispersion of the defect atoms, determination of the phase structure of a crystal, and selective PXR action in organic compounds, important for medical and biological research, are considered.

Feranchuk, I. D.; Lobko, A. S.

2008-09-01

89

Measuring the x-ray resolving power of bent potassium acid phthalate diffraction crystalsa)  

NASA Astrophysics Data System (ADS)

This report presents the results from measuring the X-ray resolving power of a curved potassium acid phthalate (KAP(001)) spectrometer crystal using two independent methods. It is part of a continuing effort to measure the fundamental diffraction properties of bent crystals that are used to study various characteristics of high temperature plasmas. Bent crystals like KAP(001) do not usually have the same diffraction properties as corresponding flat crystals. Models that do exist to calculate the effect of bending the crystal on the diffraction properties have simplifying assumptions and their accuracy limits have not been adequately determined. The type of crystals that we measured is being used in a spectrometer on the Z machine at Sandia National Laboratories in Albuquerque, New Mexico. The first technique for measuring the crystal resolving power measures the X-ray spectral line width of the characteristic lines from several metal anodes. The second method uses a diode X-ray source and a double crystal diffractometer arrangement to measure the reflectivity curve of the KAP(001) crystal. The width of that curve is inversely proportional to the crystal resolving power. The measurement results are analyzed and discussed.

Haugh, M. J.; Wu, M.; Jacoby, K. D.; Loisel, G. P.

2014-11-01

90

High Angular Resolution X-Ray Astronomy with Diffractive-Refractive Elements  

Microsoft Academic Search

No future grazing incidence X-ray telescope is likely to have an angular resolution that is signficantly superior to the Chandra X-Ray Observatory s Better angular resolution requires a new technology I describe an X-ray imaging system that has the potential to do based upon diffractive-refractive optics that transmit rather than reflect X-rays These optics are much less sensitive to figure

P. Gorenstein

2006-01-01

91

X-Ray Absorbed, Broad-Lined, Red AGN and the Cosmic X-Ray Background  

NASA Technical Reports Server (NTRS)

We have obtained XMM spectra for five red, 2MASS AGN, selected from a sample observed by Chandra to be X-ray bright and to cover a range of hardness ratios. Our results confirm the presence of substantial absorbing material in three sources which have optical classifications ranging from Type 1 to Type 2, with an intrinsically flat (hard) power law continuum indicated in the other two. The presence of both X-ray absorption and broad optical emission lines with the usual strength suggests either a small (nuclear) absorber or a favored viewing angle so as to cover the X-ray source but not the broad emission line region (BELR). A soft excess is detected in all three Type 1 sources. We speculate that this soft X-ray emission may arise in an extended region of ionized gas, perhaps linked with the polarized (scattered) light which is a feature of these sources. The spectral complexity revealed by XMM emphasizes the limitations of the low S/N Chandra data. Overall, the new XMM results strengthen our conclusions (Wilkes et al. 2002) that the observed X-ray continua of red AGN are unusually hard at energies greater than 2 keV. Whether due to substantial line-of-sight absorption or to an intrinsically hard or reflection-dominated spectrum, these 'red' AGN have an observed spectral form consistent with contributing significantly to the missing had absorbed population of the Cosmic X-ray Background (CXRB). When absorption and or reflection is taken into account, all these AGN have power law slopes typical of broad-line (Type 1) AGN (Gamma approximately 1.9). This appears to resolve the spectral paradox which for so long has existed between the CXRB and the AGN thought to be the dominant contributors. It also suggests two scenarios whereby Type 1 AGN/QSOs may be responsible for a significant fraction of the CXRB at energies above 2 keV: 1) X-ray absorbed AGN/QSOs with visible broad emission lines; 2) AGN/QSOs with complex spectra whose hardness greater than 2 keV is not detectable in the typically low S/N data of X-ray surveys. Even if absorption is present in only half of the population, the large number of 'red' AGN suggests a development of unification models, where the continuum source is surrounded, over a substantial solid angle, by the wind or atmosphere of an accretion disk/torus. X-ray observations of such AGN not only provide a check on the presence of absorption, but also a unique probe of the absorbing material. Improved information on their space density, in particular as a function of redshift, will soon be provided by Spitzer-Chandra wide area surveys, allowing better estimates of both the importance of red AGN to the full AGN population and their contribution to the CXRB.

Mushotzky, Richard (Technical Monitor); Wilkes, Belinda

2005-01-01

92

Lattice Misfit Measurement in Inconel 625 BY X-Ray Diffraction Technique  

NASA Astrophysics Data System (ADS)

Determination of lattice misfit and microstructural parameters of the coherent precipitates in Ni based alloy Inconel-625 is a challenging problem as the diffraction peaks of the precipitate and the matrix are completely overlapping. X-ray Diffraction Line Profile Analysis (XRDLPA) has been used to characterize the bulk samples of Inconel 625 at different heat-treated conditions to determine the lattice parameters of the parent phase and also the coherent precipitates by the separation of the overlapping peaks. The lattice misfits of the coherent precipitates with the matrix and their microstructural parameters like size and strain have also been determined.

Sarkar, A.; Mukherjee, P.; Barat, P.; Jayakumar, T.; Mahadevan, S.; Rai, Sanjay K.

93

Soft X-Ray Diffraction Microscopy of a Frozen Hydrated Yeast Cell  

PubMed Central

We report the first image of an intact, frozen hydrated eukaryotic cell using x-ray diffraction microscopy, or coherent x-ray diffraction imaging. By plunge freezing the specimen in liquid ethane and maintaining it below ?170 °C, artifacts due to dehydration, ice crystallization, and radiation damage are greatly reduced. In this example, coherent diffraction data using 520 eV x rays were recorded and reconstructed to reveal a budding yeast cell at a resolution better than 25 nm. This demonstration represents an important step towards high resolution imaging of cells in their natural, hydrated state, without limitations imposed by x-ray optics. PMID:20365955

Huang, Xiaojing; Nelson, Johanna; Kirz, Janos; Lima, Enju; Marchesini, Stefano; Miao, Huijie; Neiman, Aaron M.; Shapiro, David; Steinbrener, Jan; Stewart, Andrew; Turner, Joshua J.; Jacobsen, Chris

2010-01-01

94

X-ray diffraction and extended X-ray absorption fine structure study using synchrotron radiation of cobalt (II) complexes  

NASA Astrophysics Data System (ADS)

XRD and EXAFS investigation of cobalt (II) macro cyclic complexes were carried out. These complexes were synthesised by chemical rout method. On the analysis of the complexes with X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS), XRD analysis shows that complexes are crystalline in nature and having particle size and lattice parameter in the rang of few micro meter and EXAFS technique extract the local structure of complexes. The nearest neighbouring atom distance commonly known as 'bond length' were calculated using Fourier transform method. The bond lengths determined from these methods were also compared with the bond length obtained from several other known technique.

Mishra, Ashotosh; Shukla, Kritika; Dwivedi, Jagrati; Ninama, Samrath

2014-09-01

95

Fabrication of X-rays mask with carbon membrane for diffraction gratings  

Microsoft Academic Search

We have produced diffraction gratings for obtaining high resolution X-ray phase imaging, such as X-ray Talbot interferometer.\\u000a These diffraction gratings were required to have a fine, high accuracy, high aspect ratio structure. Therefore, we decided\\u000a to use the X-rays lithography technique that used synchrotron radiation of the directivity for a manufacture process. The\\u000a accuracy of the completed structure depends largely

Naoki Takahashi; Hiroshi Tujii; Megumi Katori; Kenji Yamashita; Daiji Noda; Tadashi Hattori

2010-01-01

96

X-Ray-fluorescent Fe K? Lines from Stellar Photospheres  

NASA Astrophysics Data System (ADS)

X-ray spectra from stellar coronae are reprocessed by the underlying photosphere through scattering and photoionization events. While reprocessed X-ray spectra reaching a distant observer are at a flux level of only a few percent of that of the corona itself, characteristic lines formed by inner shell photoionization of some abundant elements can be significantly stronger. The emergent photospheric spectra are sensitive to the distance and location of the fluorescing radiation and can provide diagnostics of coronal geometry and abundance. Here we present Monte Carlo simulations of the photospheric K?1,?2 doublet arising from quasi-neutral Fe irradiated by a coronal X-ray source. Fluorescent line strengths have been computed as a function of the height of the radiation source, the temperature of the ionizing X-ray spectrum, and the viewing angle. We also illustrate how the fluorescence efficiencies scale with the photospheric metallicity and the Fe abundance. Based on the results we make three comments: (1) fluorescent Fe lines seen from pre-main-sequence stars mostly suggest flared disk geometries and/or supersolar disk Fe abundances; (2) the extreme ~1400 mÅ line observed from a flare on V1486 Ori could be explained entirely by X-ray fluorescence if the flare itself were partially eclipsed by the limb of the star; and (3) the fluorescent Fe line detected by Swift during a large flare on II Peg is consistent with X-ray excitation and does not require a collisional ionization contribution. There is no convincing evidence supporting the energetically challenging explanation of electron impact excitation for observed stellar Fe K? lines.

Drake, Jeremy J.; Ercolano, Barbara; Swartz, Douglas A.

2008-05-01

97

Simultaneous X-ray diffraction and differential thermal analysis of polymers  

Microsoft Academic Search

Simultaneous measurement of X-ray diffraction patterns and differential temperature curves is an excellent method to eliminate the disadvantages in common DSC analysis. Problems in DSC analysis of polymers include phenomena such as multiple melting and fractionated crystallization. By simultaneous registration of X-ray diffraction patterns the melting and crystallization peaks can be assigned to different phases in multiphase materials. A sample

R. Androsch; M. Stolp; H.-J. Radusch

1996-01-01

98

IDENTIFICATION OF COMPOUNDS IN PARTICULATE POLLUTION BY X-RAY DIFFRACTION  

EPA Science Inventory

X-ray diffraction is a valuable tool for the identification of crystalline compounds in a multicomponent sample. Two x-ray diffraction techniques (Seeman-Bohlin and Bragg-Brentano) were examined for the identification of small amounts of material deposited on low-mass substrates....

99

A Computer Program for Calculation of Calibration Curves for Quantitative X-Ray Diffraction Analysis.  

ERIC Educational Resources Information Center

Describes a FORTRAN IV program written to supplement a laboratory exercise dealing with quantitative x-ray diffraction analysis of mixtures of polycrystalline phases in an introductory course in x-ray diffraction. Gives an example of the use of the program and compares calculated and observed calibration data. (Author/GS)

Blanchard, Frank N.

1980-01-01

100

X-Ray Diffraction and the Discovery of the Structure of DNA  

ERIC Educational Resources Information Center

A method is described for teaching the analysis of X-ray diffraction of DNA through a series of steps utilizing the original methods used by James Watson, Francis Crick, Maurice Wilkins and Rosalind Franklin. The X-ray diffraction pattern led to the conclusion of the basic helical structure of DNA and its dimensions while basic chemical principles…

Crouse, David T.

2007-01-01

101

Diffraction and imaging study of imperfections of crystallized lysozyme with coherent X-rays  

NASA Technical Reports Server (NTRS)

Phase-contrast X-ray diffraction imaging and high-angular-resolution diffraction combined with phase-contrast radiographic imaging were employed to characterize defects and perfection of a uniformly grown tetragonal lysozyme crystal in the symmetric Laue case. The full-width at half-maximum (FWHM) of a 4 4 0 rocking curve measured from the original crystal was approximately 16.7 arcsec and imperfections including line defects, inclusions and other microdefects were observed in the diffraction images of the crystal. The observed line defects carry distinct dislocation features running approximately along the <1 1 0> growth front and have been found to originate mostly in a central growth area and occasionally in outer growth regions. Inclusions of impurities or formations of foreign particles in the central growth region are resolved in the images with high sensitivity to defects. Slow dehydration led to the broadening of a fairly symmetric 4 4 0 rocking curve by a factor of approximately 2.6, which was primarily attributed to the dehydration-induced microscopic effects that are clearly shown in X-ray diffraction images. The details of the observed defects and the significant change in the revealed microstructures with drying provide insight into the nature of imperfections, nucleation and growth, and the properties of protein crystals.

Hu, Z. W.; Chu, Y. S.; Lai, B.; Thomas, B. R.; Chernov, A. A.

2004-01-01

102

perovskite: a single-crystal X-ray diffraction study  

NASA Astrophysics Data System (ADS)

Magnesium silicate perovskite is the predominant phase in the Earth's lower mantle, and it is well known that incorporation of iron has a strong effect on its crystal structure and physical properties. To constrain the crystal chemistry of (Mg, Fe)SiO3 perovskite more accurately, we synthesized single crystals of Mg0.946(17)Fe0.056(12)Si0.997(16)O3 perovskite at 26 GPa and 2,073 K using a multianvil press and investigated its crystal structure, oxidation state and iron-site occupancy using single-crystal X-ray diffraction and energy-domain Synchrotron Mössbauer Source spectroscopy. Single-crystal refinements indicate that all iron (Fe2+ and Fe3+) substitutes on the A-site only, where based on Mössbauer spectroscopy. Charge balance likely occurs through a small number of cation vacancies on either the A- or the B-site. The octahedral tilt angle ( ?) calculated for our sample from the refined atomic coordinates is 20.3°, which is 2° higher than the value calculated from the unit-cell parameters ( a = 4.7877 Å, b = 4.9480 Å, c = 6.915 Å) which assumes undistorted octahedra. A compilation of all available single-crystal data (atomic coordinates) for (Mg, Fe)(Si, Al)O3 perovskite from the literature shows a smooth increase of ? with composition that is independent of the nature of cation substitution (e.g., or substitution mechanism), contrary to previous observations based on unit-cell parameter calculations.

Sinmyo, Ryosuke; Bykova, Elena; McCammon, Catherine; Kupenko, Ilya; Potapkin, Vasily; Dubrovinsky, Leonid

2014-06-01

103

X-rayEmissionfromMassiveStars: UsingEmissionLineProfilestoConstrainWind  

E-print Network

X-rayEmissionfromMassiveStars: UsingEmissionLineProfilestoConstrainWind Kinematics Introduction:thecontextofhotstarX-rays Lineprofilediagnostics Whatdotheobservationslooklike? Whattrendsemerge? Pup:windX-rays,butlessabsorptionthanexpected OriandOri:similarsituation,verylittlewind absorption

Cohen, David

104

Synchrotron X-Ray Diffraction Analysis of Meteorites in Thin Section: Preliminary Results  

NASA Technical Reports Server (NTRS)

X-ray diffraction is the pre-eminent technique for mineral identification and structure determination, but is difficult to apply to grains in thin section, the standard meteorite preparation. Bright focused X-ray beams from synchrotrons have been used extensively in mineralogy and have been applied to extraterrestrial particles. The intensity and small spot size achievable in synchrotron X-ray beams makes them useful for study of materials in thin sections. Here, we describe Synchrotron X-ray Diffraction (SXRD) in thin section as done at the National Synchrotron Light Source, and cite examples of its value for studies of meteorites in thin section.

Treiman, A. H.; Lanzirotti, A.; Xirouchakis, D.

2004-01-01

105

On line shape analysis in X-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

Any solid state X-ray photoelectron spectrum (XPS) contains contributions due to multiple inelastic scattering in the bulk, surface excitations, energy losses originating from the screening of the final state hole (intrinsic losses), and, for non-monochromatized incident radiation, ghost lines originating from the X-ray satellites. In the present paper it is shown how all these contributions can be consecutively removed from an experimental spectrum employing a single general deconvolution procedure. Application of this method is possible whenever the contributions mentioned above are uncorrelated. It is shown that this is usually true in XPS to a good approximation. The method is illustrated on experimental non-monochromatized MgK? spectra of Au acquired at different detection angles but for the same angle of incidence of the X-rays.

Werner, Wolfgang S. M.; Cabela, Thomas; Zemek, Josef; Jiricek, Petr

2001-01-01

106

X-ray diffraction on spider silk during controlled extrusion under a synchrotron radiation X-ray beam.  

PubMed

The structure of a single thread of Nephila edulis silk has been studied by in situ X-ray diffraction from a living spider. A systematic increase of orientational order with increasing silking speed up to 40 mm s-1 was observed. Within a few mm from the spinnerets exit, crystalline domains with a beta-poly(L-alanine) structure were observed. The data also suggest an increase in crystalline fraction in the immediate vicinity of the spigot exit. PMID:11710191

Riekel, C; Madsen, B; Knight, D; Vollrath, F

2000-01-01

107

Determination of quartz in bauxite by a combined X-ray diffraction and X-ray fluorescence method  

Microsoft Academic Search

Quartz is one of the important phase constituents of any bauxite and may vary from a small fraction to over 50% of the total SiO2 concentration. At present, the most practical method of estimating quartz is by wet chemistry or by using conventional X-ray diffraction (XRD) methods. Whether employing a direct or Rietveld approach, the XRD method is difficult and

Frank R. Feret; Daniel Roy

2002-01-01

108

Real-time X-ray Diffraction Measurements of Shocked Polycrystalline Tin and Aluminum  

SciTech Connect

A new, fast, single-pulse x-ray diffraction (XRD) diagnostic for determining phase transitions in shocked polycrystalline materials has been developed. The diagnostic consists of a 37-stage Marx bank high-voltage pulse generator coupled to a needle-and-washer electron beam diode via coaxial cable, producing line and bremsstrahlung x-ray emission in a 35-ns pulse. The characteristic K? lines from the selected anodes of silver and molybdenum are used to produce the diffraction patterns, with thin foil filters employed to remove the characteristic K? line emission. The x-ray beam passes through a pinhole collimator and is incident on the sample with an approximately 3-mm by 6-mm spot and 1° full-width-half-maximum (FWHM) angular divergence in a Bragg-reflecting geometry. For the experiments described in this report, the angle between the incident beam and the sample surface was 8.5°. A Debye-Scherrer diffraction image was produced on a phosphor located 76 mm from the polycrystalline sample surface. The phosphor image was coupled to a charge-coupled device (CCD) camera through a coherent fiberoptic bundle. Dynamic single-pulse XRD experiments were conducted with thin foil samples of tin, shock loaded with a 1-mm vitreous carbon back window. Detasheet high explosive with a 2-mm-thick aluminum buffer was used to shock the sample. Analysis of the dynamic shock-loaded tin XRD images revealed a phase transformation of the tin beta phase into an amorphous or liquid state. Identical experiments with shock-loaded aluminum indicated compression of the face-centered-cubic (fcc) aluminum lattice with no phase transformation.

Dane V. Morgan, Don Macy, Gerald Stevens

2008-11-22

109

Real-time x-ray diffraction measurements of shocked polycrystalline tin and aluminum  

NASA Astrophysics Data System (ADS)

A new, fast, single-pulse x-ray diffraction (XRD) diagnostic for determining phase transitions in shocked polycrystalline materials has been developed. The diagnostic consists of a 37-stage Marx bank high-voltage pulse generator coupled to a needle-and-washer electron beam diode via coaxial cable, producing line and bremsstrahlung x-ray emission in a 35 ns pulse. The characteristic K? lines from the selected anodes of silver and molybdenum are used to produce the diffraction patterns, with thin foil filters employed to remove the characteristic K? line emission. The x-ray beam passes through a pinhole collimator and is incident on the sample with an approximately 3×6 mm2 spot and 1° full width half maximum angular divergence in a Bragg-reflecting geometry. For the experiments described in this report, the angle between the incident beam and the sample surface was 8.5°. A Debye-Scherrer diffraction image was produced on a phosphor located 76 mm from the polycrystalline sample surface. The phosphor image was coupled to a charge-coupled device camera through a coherent fiber-optic bundle. Dynamic single-pulse XRD experiments were conducted with thin foil samples of tin, shock loaded with a 1 mm vitreous carbon back window. Detasheet high explosive with a 2-mm-thick aluminum buffer was used to shock the sample. Analysis of the dynamic shock-loaded tin XRD images revealed a phase transformation of the tin beta phase into an amorphous or liquid state. Identical experiments with shock-loaded aluminum indicated compression of the face-centered-cubic aluminum lattice with no phase transformation.

Morgan, Dane V.; Macy, Don; Stevens, Gerald

2008-11-01

110

XPS and X-ray diffraction studies of aluminum-doped zinc oxide transparent conducting films  

Microsoft Academic Search

Aluminum-doped zinc oxide transparent conducting films are prepared by spray pyrolysis at different dopant concentrations. These films are subsequently characterized by X-ray diffractometric and X-ray photoelectron spectroscopic (XPS) techniques. The results are compared with those obtained from pure zinc oxide films prepared under identical conditions. X-ray diffraction measurements show an increase in lattice parameters (c and a) for aluminum-doped films

T. B. Ghosh; K. L. Chopra; H. N. Acharya

1996-01-01

111

Characterization of microstructures in Inconel 625 using X-ray diffraction peak broadening and lattice parameter measurements  

Microsoft Academic Search

This study demonstrates that, three parameters which are microstrain, lattice parameter and crystallite size, obtained from X-ray diffraction line profile analysis, can be used in a complementary way to study the precipitation\\/dissolution of various intermetallics and carbides in nickel base superalloy Inconel 625, without extracting the precipitates from the matrix.

Sanjay K. Rai; Anish Kumar; Vani Shankar; T. Jayakumar; K. Bhanu Sankara Rao; Baldev Raj

2004-01-01

112

Femtosecond X-ray diffraction from two-dimensional protein crystals.  

PubMed

X-ray diffraction patterns from two-dimensional (2-D) protein crystals obtained using femtosecond X-ray pulses from an X-ray free-electron laser (XFEL) are presented. To date, it has not been possible to acquire transmission X-ray diffraction patterns from individual 2-D protein crystals due to radiation damage. However, the intense and ultrafast pulses generated by an XFEL permit a new method of collecting diffraction data before the sample is destroyed. Utilizing a diffract-before-destroy approach at the Linac Coherent Light Source, Bragg diffraction was acquired to better than 8.5?Å resolution for two different 2-D protein crystal samples each less than 10?nm thick and maintained at room temperature. These proof-of-principle results show promise for structural analysis of both soluble and membrane proteins arranged as 2-D crystals without requiring cryogenic conditions or the formation of three-dimensional crystals. PMID:25075325

Frank, Matthias; Carlson, David B; Hunter, Mark S; Williams, Garth J; Messerschmidt, Marc; Zatsepin, Nadia A; Barty, Anton; Benner, W Henry; Chu, Kaiqin; Graf, Alexander T; Hau-Riege, Stefan P; Kirian, Richard A; Padeste, Celestino; Pardini, Tommaso; Pedrini, Bill; Segelke, Brent; Seibert, M Marvin; Spence, John C H; Tsai, Ching-Ju; Lane, Stephen M; Li, Xiao-Dan; Schertler, Gebhard; Boutet, Sebastien; Coleman, Matthew; Evans, James E

2014-03-01

113

Resolution enhancement in coherent x-ray diffraction imaging by overcoming instrumental noise.  

PubMed

We report that reference objects, strong scatterers neighboring weak phase objects, enhance the phase retrieval and spatial resolution in coherent x-ray diffraction imaging (CDI). A CDI experiment with Au nano-particles exhibited that the reference objects amplified the signal-to-noise ratio in the diffraction intensity at large diffraction angles, which significantly enhanced the image resolution. The interference between the diffracted x-ray from reference objects and a specimen also improved the retrieval of the phase of the diffraction signal. The enhancement was applied to image NiO nano-particles and a mitochondrion and confirmed in a simulation with a bacteria phantom. We expect that the proposed method will be of great help in imaging weakly scattering soft matters using coherent x-ray sources including x-ray free electron lasers. PMID:25402155

Kim, Chan; Kim, Yoonhee; Song, Changyong; Kim, Sang Soo; Kim, Sunam; Kang, Hyon Chol; Hwu, Yeukuang; Tsuei, Ku-Ding; Liang, Keng San; Noh, Do Young

2014-11-17

114

Femtosecond X-ray diffraction from two-dimensional protein crystals  

PubMed Central

X-ray diffraction patterns from two-dimensional (2-D) protein crystals obtained using femtosecond X-ray pulses from an X-ray free-electron laser (XFEL) are presented. To date, it has not been possible to acquire transmission X-ray diffraction patterns from individual 2-D protein crystals due to radiation damage. However, the intense and ultrafast pulses generated by an XFEL permit a new method of collecting diffraction data before the sample is destroyed. Utilizing a diffract-before-destroy approach at the Linac Coherent Light Source, Bragg diffraction was acquired to better than 8.5?Å resolution for two different 2-D protein crystal samples each less than 10?nm thick and maintained at room temperature. These proof-of-principle results show promise for structural analysis of both soluble and membrane proteins arranged as 2-D crystals without requiring cryogenic conditions or the formation of three-dimensional crystals. PMID:25075325

Frank, Matthias; Carlson, David B.; Hunter, Mark S.; Williams, Garth J.; Messerschmidt, Marc; Zatsepin, Nadia A.; Barty, Anton; Benner, W. Henry; Chu, Kaiqin; Graf, Alexander T.; Hau-Riege, Stefan P.; Kirian, Richard A.; Padeste, Celestino; Pardini, Tommaso; Pedrini, Bill; Segelke, Brent; Seibert, M. Marvin; Spence, John C. H.; Tsai, Ching-Ju; Lane, Stephen M.; Li, Xiao-Dan; Schertler, Gebhard; Boutet, Sebastien; Coleman, Matthew; Evans, James E.

2014-01-01

115

(X-ray diffraction experiments with condenser matter)  

SciTech Connect

This report discusses research on the following topics: high-{Tc} superconductors; The response of crystal to an applied electric field; quasicrystals; surface structure and kinetics of surface layer formation; EXAFS studies of superconductors and heterostructures; effect of iron on the crystal structure of perovskite; x-ray detector development; and SAXS experiments. (LSP)

Coppens, P.

1990-01-01

116

Quantitative x-ray diffraction phase analysis of coarse airborne particulate collected by cascade impactor sampling  

Microsoft Academic Search

Mineralogical composition of Castellon (Spanish Mediterranean coast) atmospheric aerosol was studied by X-ray diffraction by sampling with a cascade impactor without filters. Quantitative phase analysis of natural phases present in the atmospheric coarse aerosol was performed using a modified version of the computer program MENGE, that uses the standardless X-ray method developed by Rius for the quantitative analysis of multiphase

L. E. Ochando; J. M. Amigó

1997-01-01

117

X-RAY DIFFRACTION PHASE ANALYSIS OF PROCESS AND POLLUTION CONTROL DEVICE SAMPLES  

EPA Science Inventory

The paper describes the application of x-ray diffraction (XRD) analysis to several samples which show the information available from the technique. X-ray fluorescence (XRF) spectrometry was used for the elemental analysis because it provides very complete information with minimal...

118

H. Ihee et al., "Ultrafast X-ray diffraction of transient molecular structures in solution."  

E-print Network

H. Ihee et al., "Ultrafast X-ray diffraction of transient molecular structures in solutionV. The scattered X-ray signal was recorded on a 133 mm diameter fiber-coupled MarCCD at well-defined delay times (t of the parent molecule, the transient intermediates and the products in the gas phase and in solution, were

Ihee, Hyotcherl

119

Line-Focus Generation for X-Ray Laser Pumping  

NASA Astrophysics Data System (ADS)

Down-scaling of X-ray lasers towards shorter wavelengths imposes the need for higher irradiance of the pump laser systems. Typically, for a factor of 2 reduction in wavelength, a factor of ˜10 increase in irradiance was so far required. This discourages the use of refractive optics after the compressor stage of the high-power CPA laser systems commonly used for pumping X-ray lasers due to increasing nonlinear phase distortion (B-Integral). We present ray-tracing calculations of alternative focusing schemes applying reflective optics for grazing-incidence line-focus generation. The proposed mirrors deliver a narrow and shortened line focus from a high-aperture input beam, yielding an increase of irradiance on target.

Staub, F.; Bleiner, D.; Jia, F.; Balmer, J. E.

120

High-resolution x-ray diffraction microscopy of specifically labeled yeast cells  

E-print Network

High-resolution x-ray diffraction microscopy of specifically labeled yeast cells Johanna Nelsona,1 of the yeast Saccharomyces cerevisiae. Cells were plunge-frozen in liquid ethane and freeze-dried, after which

Mohseni, Hooman

121

[Research on the silk aging with x-ray diffraction spectra].  

PubMed

The present paper did some researches on the deterioration mechanism and the changes in crystallinity of silk fabrics by means of the X-ray diffraction analysis. The samples artificially aged and excavated from Hubei, Innermongolia, Shaanxi and Qinghai provinces were analyzed. The artificial aging was done by simulating three main natural aging factors: light, heat and hydrolysis. The analytical results show that X-ray diffraction analysis could reveal the aging process and characteristic of silk, as well as the changes in crystallinity during silk aging. The X-ray diffraction analysis is of practical value for the conservation state and aging mechanism studies of ancient silk. In addition, X-ray diffraction analysis could also provide important information on ancient technology of textile and apparel. PMID:20302128

Zhang, Xiao-mei; Yuan, Si-xun

2010-01-01

122

High numerical aperture tabletop soft x-ray diffraction microscopy with 70-nm resolution  

PubMed Central

Light microscopy has greatly advanced our understanding of nature. The achievable resolution, however, is limited by optical wavelengths to ?200 nm. By using imaging and labeling technologies, resolutions beyond the diffraction limit can be achieved for specialized specimens with techniques such as near-field scanning optical microscopy, stimulated emission depletion microscopy, and photoactivated localization microscopy. Here, we report a versatile soft x-ray diffraction microscope with 70- to 90-nm resolution by using two different tabletop coherent soft x-ray sources—a soft x-ray laser and a high-harmonic source. We also use field curvature correction that allows high numerical aperture imaging and near-diffraction-limited resolution of 1.5?. A tabletop soft x-ray diffraction microscope should find broad applications in biology, nanoscience, and materials science because of its simple optical design, high resolution, large depth of field, 3D imaging capability, scalability to shorter wavelengths, and ultrafast temporal resolution. PMID:18162534

Sandberg, Richard L.; Song, Changyong; Wachulak, Przemyslaw W.; Raymondson, Daisy A.; Paul, Ariel; Amirbekian, Bagrat; Lee, Edwin; Sakdinawat, Anne E.; La-O-Vorakiat, Chan; Marconi, Mario C.; Menoni, Carmen S.; Murnane, Margaret M.; Rocca, Jorge J.; Kapteyn, Henry C.; Miao, Jianwei

2008-01-01

123

State-of-the-art and problems of X-ray diffraction analysis of biomacromolecules  

NASA Astrophysics Data System (ADS)

The state-of-the-art of X-ray diffraction studies of biomacromolecules is briefly characterized, and the challenge imposed by science is discussed. These studies are characterized by a wide scope and extensive use. This field of science is of great interest and is developed in many countries. The main purpose is to solve practical problems in medicine consisting in the design of drugs against various diseases. X-ray diffraction analysis of enzymes brought the pharmaceutical industry to a new level, thus allowing the rational design of drugs against formerly untreatable diseases. Modern X-ray diffraction studies of biomacromolecules laid the basis for a new science called structural biology. This method allows one to solve fundamental problems of physical chemistry for a new state of matter existing in living systems. Here, science poses numerous problems in analysis of X-ray diffraction data on biological macromolecules. Many of theses problems are in their infancy.

Andreeva, N. S.

2006-12-01

124

Mass Spectra and X-Ray Powder Diffraction Studies on Some Ethanolamine and Quinolone Complexes  

Microsoft Academic Search

The mass spectra and X-ray powder diffraction studies of some ethanolamine and 2-quinolone complexes are discussed. The fragmentation pattern and mode of bonding were suggested. The data were explained based on the molecular structure.

Mohyi M. El-essawi; Mamdouh S. Masoud; Amira M. Amr

1990-01-01

125

Method for improve x-ray diffraction determinations of residual stress in nickel-base alloys  

DOEpatents

A process for improving the technique of measuring residual stress by x-ray diffraction in pieces of nickel-base alloys which comprises covering part of a predetermined area of the surface of a nickel-base alloy with a dispersion, exposing the covered and uncovered portions of the surface of the alloy to x-rays by way of an x-ray diffractometry apparatus, making x-ray diffraction determinations of the exposed surface, and measuring the residual stress in the alloy based on these determinations. The dispersion is opaque to x-rays and serves a dual purpose since it masks off unsatisfactory signals such that only a small portion of the surface is measured, and it supplies an internal standard by providing diffractogram peaks comparable to the peaks of the nickel alloy so that the alloy peaks can be very accurately located regardless of any sources of error external to the sample.

Berman, Robert M. (Pittsburgh, PA); Cohen, Isadore (Pittsburgh, PA)

1990-01-01

126

Method for improving x-ray diffraction determinations of residual stress in nickel-base alloys  

DOEpatents

A process for improving the technique of measuring residual stress by x-ray diffraction in pieces of nickel-base alloys is discussed. Part of a predetermined area of the surface of a nickel-base alloy is covered with a dispersion. This exposes the covered and uncovered portions of the surface of the alloy to x-rays by way of an x-ray diffractometry apparatus, making x-ray diffraction determinations of the exposed surface, and measuring the residual stress in the alloy based on these determinations. The dispersion is opaque to x-rays and serves a dual purpose, since it masks off unsatisfactory signals such that only a small portion of the surface is measured, and it supplies an internal standard by providing diffractogram peaks comparable to the peaks of the nickel alloy so that the alloy peaks can be very accurately located regardless of any sources of error external to the sample. 2 figs.

Berman, R.M.; Cohen, I.

1988-04-26

127

Ris-R-1266(EN) The 3D X-Ray Diffraction Microscope  

E-print Network

Risø-R-1266(EN) The 3D X-Ray Diffraction Microscope and its Application to the Study Preface 3 1 Introduction 5 2 The 3D X-Ray Diffraction Microscope 7 2.1 Experimental set-up 8 2.1.1 The x.3 Discussion and outlook 27 3 Recrystallization Kinetics and the 3DXRD Microscope 29 3.1 Experimental 30 3

128

Measurement of piezoelectric constants of lanthanum-gallium tantalate crystal by X-ray diffraction methods  

SciTech Connect

A method for measuring piezoelectric constants of crystals of intermediate systems by X-ray quasi-multiple-wave diffraction is proposed and implemented. This technique makes it possible to determine the piezoelectric coefficient by measuring variations in the lattice parameter under an external electric field. This method has been approved, its potential is evaluated, and a comparison with high-resolution X-ray diffraction data is performed.

Blagov, A. E.; Marchenkov, N. V., E-mail: marchenkov@ns.crys.ras.ru; Pisarevsky, Yu. V.; Prosekov, P. A.; Kovalchuk, M. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2013-01-15

129

X-ray diffraction characterization of suspended structures forMEMS applications  

SciTech Connect

Mechanical stress control is becoming one of the major challenges for the future of micro and nanotechnologies. Micro scanning X-ray diffraction is one of the promising techniques that allows stress characterization in such complex structures at sub micron scales. Two types of MEMS structure have been studied: a bilayer cantilever composed of a gold film deposited on poly-silicon and a boron doped silicon bridge. X-ray diffraction results are discussed in view of numerical simulation experiments.

Goudeau, P.; Tamura, N.; Lavelle, B.; Rigo, S.; Masri, T.; Bosseboeuf, A.; Sarnet, T.; Petit, J.-A.; Desmarres, J.-M.

2005-09-15

130

Submicron X-Ray Diffraction and Its Applications to Problems in Materials and Environmental Science  

Microsoft Academic Search

The availability of high brilliance 3rd generation synchrotron sources together with progress in achromatic focusing optics allow to add submicron spatial resolution to the conventional century-old X-ray diffraction technique. The new capabilities include the possibility to map in-situ, grain orientations, crystalline phase distribution and full strain\\/stress tensors at a very local level, by combining white and monochromatic X-ray microbeam diffraction.

N. Tamura; R. S. Celestre; A. A. MacDowell; H. A. Padmore; R. Spolenak; B. C. Valek; N. Meier Chang; A. Manceau; J. R. Patel

2002-01-01

131

Time-resolved x-ray diffraction study of photostimulated purple membrane.  

PubMed Central

A nanosecond resolution laser-driven x-ray source has been used to perform a time-resolved, x-ray diffraction study of the purple membrane of the Halobacterium halobium. Alterations in diffraction patterns have been observed 1 ms after photostimulation, and are interpreted to show disorder of bacteriorhodopsin packing in the plane of the membrane with little bacteriorhodopsin structural change. PMID:3978209

Frankel, R D; Forsyth, J M

1985-01-01

132

Study of partial melting at high-pressure using in situ X-ray diffraction  

Microsoft Academic Search

The high-pressure melting behavior of different iron alloys was investigated using the classical synchrotron-based in situ X-ray diffraction techniques. As they offer specific advantages and disadvantages, both energy-dispersive (EDX) and angle-dispersive (ADX) X-ray diffraction methods were performed at the BL04B1 beamline of SPring8 (Japan) and at the ID27-30 beamline of the ESRF (France), respectively. High-pressure vessels and pressure ranges investigated

D. Andrault; G. Morard; N. Bolfan-Casanova; O. Ohtaka; H. Fukui; H. Arima; N. Guignot; K. Funakoshi; P. Lazor; M. Mezouar

2006-01-01

133

X-ray diffraction and nanoindentation studies of nanocrystalline graphite at high pressures  

Microsoft Academic Search

We report energy dispersive x-ray diffraction studies on nanocrystalline hexagonal graphite samples (average grain size=12 nm) in a diamond-anvil cell to 65 GPa at room temperature. A structural phase transition to a hexagonal diamond phase beginning at 15 GPa is completed at 55 GPa, and is reversible on decompression. The x-ray diffraction studies were followed by nanoindentation hardness measurements on

J. Reed Patterson; Anatoliy Kudryavtsev; Yogesh K. Vohra

2002-01-01

134

Reactive sputter magnetron reactor for preparation of thin films and simultaneous in situ structural study by X-ray diffraction  

SciTech Connect

The purpose of the designed reactor is (i) to obtain polycrystalline and/or amorphous thin films by controlled deposition induced by a reactive sputtering magnetron and (ii) to perform a parallel in situ structural study of the deposited thin films by X-ray diffraction, in real time, during the whole growth process. The designed reactor allows for the control and precise variation of the relevant processing parameters, namely, magnetron target-to-sample distance, dc magnetron voltage, and nature of the gas mixture, gas pressure and temperature of the substrate. On the other hand, the chamber can be used in different X-ray diffraction scanning modes, namely, {theta}-2{theta} scanning, fixed {alpha}-2{theta} scanning, and also low angle techniques such as grazing incidence small angle X-ray scattering and X-ray reflectivity. The chamber was mounted on a standard four-circle diffractometer located in a synchrotron beam line and first used for a preliminary X-ray diffraction analysis of AlN thin films during their growth on the surface of a (100) silicon wafer.

Buergi, J.; Molleja, J. Garcia; Feugeas, J. [Instituto de Fisica Rosario (CONICET-UNR), Bv. 27 de Febrero 210 bis, S2000EZP Rosario (Argentina); Neuenschwander, R. [Laboratorio Nacional Luz Sincrotron (LNLS), Caixa Postal 6192, CEP13083-970 Campinas (Brazil); Kellermann, G. [Departamento de Fisica (Universidade Federal do Parana), Caixa Postal 19044, CEP81531-990 Curitiba (Brazil); Craievich, A. F. [Instituto de Fisica (Universidade de Sao Paulo), Rua do Matao Travessa R 187, CEP05508-090 Sao Paulo (Brazil)

2013-01-15

135

An atomic layer deposition chamber for in situ x-ray diffraction and scattering analysis  

NASA Astrophysics Data System (ADS)

The crystal structure of thin films grown by atomic layer deposition (ALD) will determine important performance properties such as conductivity, breakdown voltage, and catalytic activity. We report the design of an atomic layer deposition chamber for in situ x-ray analysis that can be used to monitor changes to the crystal structural during ALD. The application of the chamber is demonstrated for Pt ALD on amorphous SiO2 and SrTiO3 (001) using synchrotron-based high resolution x-ray diffraction, grazing incidence x-ray diffraction, and grazing incidence small angle scattering.

Geyer, Scott M.; Methaapanon, Rungthiwa; Johnson, Richard W.; Kim, Woo-Hee; Van Campen, Douglas G.; Metha, Apurva; Bent, Stacey F.

2014-05-01

136

An atomic layer deposition chamber for in situ x-ray diffraction and scattering analysis.  

PubMed

The crystal structure of thin films grown by atomic layer deposition (ALD) will determine important performance properties such as conductivity, breakdown voltage, and catalytic activity. We report the design of an atomic layer deposition chamber for in situ x-ray analysis that can be used to monitor changes to the crystal structural during ALD. The application of the chamber is demonstrated for Pt ALD on amorphous SiO2 and SrTiO3 (001) using synchrotron-based high resolution x-ray diffraction, grazing incidence x-ray diffraction, and grazing incidence small angle scattering. PMID:24880424

Geyer, Scott M; Methaapanon, Rungthiwa; Johnson, Richard W; Kim, Woo-Hee; Van Campen, Douglas G; Metha, Apurva; Bent, Stacey F

2014-05-01

137

Plasticity and X-ray Line Profile Analysis of the semicrystalline polymer poly(3-hydroxybutyrate)  

NASA Astrophysics Data System (ADS)

The evolution of the microstructure during compressive deformation of the biodegradable polymer poly(3-hydroxybutyrate) (P3HB) was investigated in-situ via X-ray diffraction using synchrotron radiation. Flow curves were measured in-situ together with X-ray profiles for several degrees of deformation. The profiles were analysed using Multi-Reflection X-ray Line Profile Analysis (MXPA) adapted by the authors for semicrystalline polymers providing lamella thickness, crystallinity, and the presence and density of dislocations as a function of the deformation. In contrast to previous investigations in ? crystallised isotactic polypropylene (?-iPP), P3HB does not exhibit a deformation induced increase of the dislocation density which suggests mechanisms other than dislocations to be involved in plastic deformation of P3HB.

Spieckermann, F.; Wilhelm, H.; Schafler, E.; Kerber, M.; Bernstorff, S.; Zehetbauer, M. J.

2010-07-01

138

In-situ X-ray diffraction system using sources and detectors at fixed angular positions  

DOEpatents

An x-ray diffraction technique for measuring a known characteristic of a sample of a material in an in-situ state. The technique includes using an x-ray source for emitting substantially divergent x-ray radiation--with a collimating optic disposed with respect to the fixed source for producing a substantially parallel beam of x-ray radiation by receiving and redirecting the divergent paths of the divergent x-ray radiation. A first x-ray detector collects radiation diffracted from the sample; wherein the source and detector are fixed, during operation thereof, in position relative to each other and in at least one dimension relative to the sample according to a-priori knowledge about the known characteristic of the sample. A second x-ray detector may be fixed relative to the first x-ray detector according to the a-priori knowledge about the known characteristic of the sample, especially in a phase monitoring embodiment of the present invention.

Gibson, David M. (Voorheesville, NY); Gibson, Walter M. (Voorheesville, NY); Huang, Huapeng (Latham, NY)

2007-06-26

139

First results from a next-generation off-plane X-ray diffraction grating  

NASA Astrophysics Data System (ADS)

Future NASA X-ray spectroscopy missions will require high throughput, high resolving power grating spectrometers. Off-plane reflection gratings are capable of meeting the performance requirements needed to realize the scientific goals of these missions. We have identified a novel grating fabrication method that utilizes common lithographic and microfabrication techniques to produce the high fidelity groove profile necessary to achieve this performance. Application of this process has produced an initial pre-master that exhibits a radial (variable line spacing along the groove dimension), high density (> 6000 grooves/mm), laminar profile. This pre-master has been tested for diffraction efficiency at the BESSY II synchrotron light facility and diffracts up to 55 % of incident light into usable spectral orders. Furthermore, tests of spectral resolving power show that these gratings are capable of obtaining resolving powers well above 1300 ( ?/? ?) with limitations due to the test apparatus, not the gratings. Obtaining these results has provided confidence that this fabrication process is capable of producing off-plane reflection gratings for the next generation of X-ray observatories.

McEntaffer, Randall; DeRoo, Casey; Schultz, Ted; Gantner, Brennan; Tutt, James; Holland, Andrew; O'Dell, Stephen; Gaskin, Jessica; Kolodziejczak, Jeffrey; Zhang, William W.; Chan, Kai-Wing; Biskach, Michael; McClelland, Ryan; Iazikov, Dmitri; Wang, Xinpeng; Koecher, Larry

2013-08-01

140

Phase Sensitive X-Ray Diffraction Imaging Study of Protein Crystals  

NASA Technical Reports Server (NTRS)

The study of defects and growth of protein crystals is of importance in providing a fundamental understanding of this important category of systems and the rationale for crystallization of better ordered crystals for structural determination and drug design. Yet, as a result of the extremely weak scattering power of x-rays in protein and other biological macromolecular crystals, the extinction lengths for those crystals are extremely large and, roughly speaking, of the order of millimeters on average compared to the scale of micrometers for most small molecular crystals. This has significant implication for x-ray diffraction and imaging study of protein crystals, and presents an interesting challenge to currently available x-ray analytical techniques. We proposed that coherence-based phase sensitive x-ray diffraction imaging could provide a way to augment defect contrast in x-ray diffraction images of weakly diffracting biological macromolecular crystals. I shall examine the principles and ideas behind this approach and compare it to other available x-ray topography and diffraction methods. I shall then present some recent experimental results in two model protein systems-cubic apofemtin and tetragonal lysozyme crystals to demonstrate the capability of the coherence-based imaging method in mapping point defects, dislocations, and the degree of perfection of biological macromolecular crystals with extreme sensitivity. While further work is under way, it is intended to show that the observed new features have yielded important information on protein crystal perfection and nucleation and growth mechanism otherwise unobtainable.

Hu, Z. W.

2003-01-01

141

Dynamical x-ray diffraction from an icosahedral Al-Pd-Mn quasicrystal  

SciTech Connect

Primary extinction effects in diffraction from single grains of Al-Pd- Mn, and presumably many other FCI alloys, may be significant and should be corrected for prior to use of diffraction data in structural determinations. Probes based on dynamical diffraction effects, such as x-ray standing wave fluorescence, multiple beam interference, and x-ray transmission topographs, may now be used to study the bulk and surface structure of some quasicrystals. The observation of dynamical diffraction from icosahedral Al-Pd-Mn is a striking confirmation of the fact that quasicrystals can present a degree of structural perfection comparable to that found in the best periodic intermetallic crystals.

Kycia, S.

1996-04-23

142

Human Interleukin4 and Variant R88Q: Phasing X-ray Diffraction Data by Molecular Replacement Using X-ray and Nuclear Magnetic Resonance Models  

Microsoft Academic Search

The structure of recombinant human interleukin-4 (hIL-4) as been determined by both NMR and X-ray diffraction methods in several laboratories, including ours. The X-ray and NMR structures were successfully applied for solving the X-ray crystal structure by molecular replacement. Due to the small size of the hIL-4 molecule (129 residues) and its lack of structural diversity (4-helix bundle), this task

Thomas Müller; Frank Oehlenschläger; Manfred Buehner

1995-01-01

143

Neutron diffraction, x-ray diffraction, and specific heat studies of orbital ordering in YVO3  

NASA Astrophysics Data System (ADS)

Neutron diffraction, synchrotron x-ray diffraction, and specific heat studies have been carried out to investigate the nature of the ordered occupation of the vanadium d orbitals in perovskite YVO3. Evidence has been found for a change in the type of orbital ordering at the 77-K phase transition in this material, manifested by a change in the type of Jahn-Teller distortion. This transition between orbital orderings is caused by an increase in octahedral tilting with decreasing temperature. The orbital ordering above 77 K is not destroyed at the magnetic ordering temperature of 116 K, but is present as far as a second structural phase transition at 200 K. The entropy changes at the onset of both spin and orbital ordering are much lower than the smallest semiclassical value of Rln2 J/(mole K).

Blake, G. R.; Palstra, T. T.; Ren, Y.; Nugroho, A. A.; Menovsky, A. A.

2002-05-01

144

Radiation response of an intraspecific somatic cell hybrid (l5178y, x-ray resistant line x l5178y, x-ray sensitive line)  

Microsoft Academic Search

The radiosensitivities of an x-ray-sensitive L5178Y line, an x-ray-resistant L5178Y line, and of two hybrid lines produced by their fusion have been studied. The hybrid cells are similar in x-ray resistance to the more resistant parent. There was no significant difference in the extrapolation number of the survival curves nor in the ability of the parental and hybrid cells to

B Dale

1979-01-01

145

In Situ Mineralogical Analysis of Planetary Materials Using X-Ray Diffraction and X-Ray Fluorescence  

NASA Technical Reports Server (NTRS)

Remote observations of Mars have led scientists to believe that its early climate was similar to that of the early Earth, having had abundant liquid water and a dense atmosphere. One of the most fascinating questions of recent times is whether simple bacterial life developed on Mars (as it did on the Earth) during this early element period. Analyses of SNC meteorites have broadened considerably our knowledge of the chemistry of certain types of Martian rocks, underscoring the tantalizing possibility of early hydrothermal systems and even of ancient bacterial life. Detailed analyses of SNC meteorites in Terrestrial laboratories utilize the most sophisticated organic, isotopic and microscopic techniques in existence. Indeed; it is unlikely that the key biogenic indicators used in McKay et al (ibid) could be identified by a remote instrument on the surface of Mars. As a result, it is probable that any robotic search for evidence of an ancient Martian biosphere will have as its focus the identification of key minerals in likely host rocks rather than the direct detection of organic or isotopic biomarkers. Even on a sample return mission, mineralogical screening will be utilized to choose the most likely candidate rocks. X-ray diffraction (XRD) is the only technique that can provide a direct determination of the crystal structures of the phases present within a sample. When many different crystalline phases are present, quantitative analysis is better constrained if used in conjunction with a determination of elemental composition, obtainable by X-ray fluorescence (XRF) using the same X-ray source as for XRD. For planetary surface analysis, a remote instrument combining XRD and XRF could be used for mineralogical characterization of both soils and rocks. We are designing a remote XRD/XRF instrument with this objective in mind. The instrument concept pays specific attention to constraints in sample preparation, weight, volume, power, etc. Based on the geometry of a pinhole camera (transmission geometry, flat two-dimensional detector perpendicular to the direct beam), the instrument (which we call CHEMIN, for Chemistry and Mineralogy) uses an X-ray sensitive CCD detector which will allow concurrent positional and energy-dispersive analysis of collected photons. Thus XRF (energy) and XRD (geometry) analysis of transmitted X-rays will be performed at the same time. Tests performed with single minerals and simple mixtures give promising results. Refinements of the prototype promise interpretable results on complex samples.

Sarrazin, P.; Blake, D.; Vaniman, D.; Chang, Sherwood (Technical Monitor)

1996-01-01

146

An instrument for combining x-ray multiple diffraction and x-ray topographic imaging for examining crystal microcrystallography and perfection  

SciTech Connect

Diffraction imaging using x-ray topography (XRT) and x-ray multiple diffraction (XRMD) provide valuable tools for examining the growth defects in crystals and the distributions from ideal lattice symmetry (microcrystallography). The topographic x-ray multiple diffraction microprobe (TMDM) combines the complementary aspects of both techniques enabling XRT and XRMD studies within the same instrument providing a useful resource for the structural characterization of materials that are not very stable in vacuum and electron beam environments. The design of the TMDM instrument is described together with data taken on GaAs (001) and potassium dihydrogen phosphate (001)

Lai, X.; Ma, C. Y.; Roberts, K. J. [Institute of Particle Science and Engineering, School of Process, Environmental and Materials Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Cardoso, L. P. [Institute of Particle Science and Engineering, School of Process, Environmental and Materials Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); IFGW, UNICAMP, CP 6165, 13083-970 Campinas, SP (Brazil); Santos, A. O. dos [IFGW, UNICAMP, CP 6165, 13083-970 Campinas, SP (Brazil); Bogg, D.; Miller, M. C. [STFC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom)

2009-03-15

147

Comparison of a CCD and an APS for soft X-ray diffraction  

NASA Astrophysics Data System (ADS)

We compare a new CMOS Active Pixel Sensor (APS) to a Princeton Instruments PIXIS-XO: 2048B Charge Coupled Device (CCD) with soft X-rays tested in a synchrotron beam line at the Diamond Light Source (DLS). Despite CCDs being established in the field of scientific imaging, APS are an innovative technology that offers advantages over CCDs. These include faster readout, higher operational temperature, in-pixel electronics for advanced image processing and reduced manufacturing cost. The APS employed was the Vanilla sensor designed by the MI3 collaboration and funded by an RCUK Basic technology grant. This sensor has 520 x 520 square pixels, of size 25 ?m on each side. The sensor can operate at a full frame readout of up to 20 Hz. The sensor had been back-thinned, to the epitaxial layer. This was the first time that a back-thinned APS had been demonstrated at a beam line at DLS. In the synchrotron experiment soft X-rays with an energy of approximately 708 eV were used to produce a diffraction pattern from a permalloy sample. The pattern was imaged at a range of integration times with both sensors. The CCD had to be operated at a temperature of -55°C whereas the Vanilla was operated over a temperature range from 20°C to -10°C. We show that the APS detector can operate with frame rates up to two hundred times faster than the CCD, without excessive degradation of image quality. The signal to noise of the APS is shown to be the same as that of the CCD at identical integration times and the response is shown to be linear, with no charge blooming effects. The experiment has allowed a direct comparison of back thinned APS and CCDs in a real soft x-ray synchrotron experiment.

Stewart, Graeme; Bates, R.; Blue, A.; Clark, A.; Dhesi, S. S.; Maneuski, D.; Marchal, J.; Steadman, P.; Tartoni, N.; Turchetta, R.

2011-12-01

148

Measurement of grain size of polycrystalline materials with confocal energy dispersive micro-X-ray diffraction technology based on polycapillary X-ray optics  

NASA Astrophysics Data System (ADS)

The confocal energy dispersive micro-X-ray diffraction (EDMXRD) based on polycapillary X-ray optics was used to determine the grain size of polycrystalline materials. The grain size of a metallographic specimen of nickel base alloy was measured by using the confocal EDMXRD. The experimental results demonstrated that the confocal EDMXRD had potential applications in measuring large grain size.

Sun, Weiyuan; Liu, Zhiguo; Sun, Tianxi; Peng, Song; Ma, Yongzhong; Li, Fangzuo; Sun, Xuepeng; Ding, Xunliang

2014-11-01

149

Weak Hard X-Ray Emission from Broad Absorption Line Quasars: Evidence for Intrinsic X-Ray Weakness  

NASA Astrophysics Data System (ADS)

We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z = 0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z < 1.3. However, their rest-frame ?2 keV luminosities are 14 to >330 times weaker than expected for typical quasars. Our results from a pilot NuSTAR study of two low-redshift BAL quasars, a Chandra stacking analysis of a sample of high-redshift BAL quasars, and a NuSTAR spectral analysis of the local BAL quasar Mrk 231 have already suggested the existence of intrinsically X-ray weak BAL quasars, i.e., quasars not emitting X-rays at the level expected from their optical/UV emission. The aim of the current program is to extend the search for such extraordinary objects. Three of the six new targets are weakly detected by NuSTAR with <~ 45 counts in the 3-24 keV band, and the other three are not detected. The hard X-ray (8-24 keV) weakness observed by NuSTAR requires Compton-thick absorption if these objects have nominal underlying X-ray emission. However, a soft stacked effective photon index (?eff ? 1.8) for this sample disfavors Compton-thick absorption in general. The uniform hard X-ray weakness observed by NuSTAR for this and the pilot samples selected with <10 keV weakness also suggests that the X-ray weakness is intrinsic in at least some of the targets. We conclude that the NuSTAR observations have likely discovered a significant population (gsim 33%) of intrinsically X-ray weak objects among the BAL quasars with significantly weak <10 keV emission. We suggest that intrinsically X-ray weak quasars might be preferentially observed as BAL quasars.

Luo, B.; Brandt, W. N.; Alexander, D. M.; Stern, D.; Teng, S. H.; Arévalo, P.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Farrah, D.; Gandhi, P.; Hailey, C. J.; Harrison, F. A.; Koss, M.; Ogle, P.; Puccetti, S.; Saez, C.; Scott, A. E.; Walton, D. J.; Zhang, W. W.

2014-10-01

150

X-ray Obscured Broad-Line AGN  

NASA Astrophysics Data System (ADS)

While the vast majority of Type I AGN show little or no X-ray obscuration, approximately 10% are heavily obscured with X-ray column densities of N_H > 10^22 cm^-2. In addition to providing a unique and necessary test of the unified model, the study of these AGN has significant consequences for our understanding of the cosmic X-ray and infrared backgrounds, and therefore for the cosmic accretion and star-formation histories of the universe. A number of explanations have been proposed to explain the seemingly contradictory behavior of these X-ray obscured, broad-line AGN, including (1) dust sublimation near the central engine, (2) dust coagulation, (3) obscuration by clouds in the broad-line region, (4) column density variability, and (5) scattering of the broad emission lines off a reflecting medium. We therefore propose for MIPS and IRAC observations of the 11 sources in our sample of 13 for which this data is not yet available. In addition, we propose low-resolution IRS spectroscopy for the brightest 5 sources as well as 1 faint source with an exceptionally high column density, and IRS Peak-Up imaging at 16 microns for the remaining 7 sources. The MIPS, IRAC, and IRS Peak-Up photometry will allow us to test for the presence of hot dust, which may be in the process of being destroyed through dust sublimation. IRS spectroscopy will allow us to test for the presence of the 9.7 micron silicate feature, which should not be present if the dust distribution is dominated by large grains as predicted in some models, or which may be seen in emission if the broad-line region clouds are themselves responsible for the odd behavior of these AGN. In combination with polarimetric data and high-quality optical spectra from the Bok 90' telescope, these observations will provide us with the ideal dataset to test concretely for the first time the many potential explanations for the strange behavior of these unexpected AGN.

Rieke, George; Donley, Jennifer; Shi, Yong; Smith, Paul

2008-03-01

151

Nanosecond x-ray Laue diffraction apparatus suitable for laser shock compression experiments.  

PubMed

We have used nanosecond bursts of x-rays emitted from a laser-produced plasma, comprised of a mixture of mid-Z elements, to produce a quasiwhite-light spectrum suitable for performing Laue diffraction from single crystals. The laser-produced plasma emits x-rays ranging in energy from 3 to in excess of 10 keV, and is sufficiently bright for single shot nanosecond diffraction patterns to be recorded. The geometry is suitable for the study of laser-shocked crystals, and single-shot diffraction patterns from both unshocked and shocked silicon crystals are presented. PMID:20815613

Suggit, Matthew; Kimminau, Giles; Hawreliak, James; Remington, Bruce; Park, Nigel; Wark, Justin

2010-08-01

152

Study on quasiperiodic Ta/Al multilayer films by x-ray diffraction  

SciTech Connect

Quasiperiodic (Fibonacci) Ta/Al multilayer films with Ta(110) and Al(111) textures were fabricated by magnetron sputtering. The structure of the multilayers was characterized in detail by x-ray diffraction. The diffraction peaks at low and high angles can be indexed by the projection method from the high-dimension periodic structure. The experimental results were in good agreement with the numerical calculation using the model for the compositionally modulated multilayers. The diffraction spectrum of the quasiperiodic Ta/Al multilayers is totally different from that of periodic structure, and the possible application of Fibonacci films as optical elements in a soft x-ray region is discussed.

Peng, R.W.; Hu, A.; Jiang, S.S. (Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210008 (People's Republic of China))

1991-11-11

153

Quantitative determination of mineral composition by powder x-ray diffraction  

DOEpatents

An external standard intensity ratio method is used for quantitatively determining mineralogic compositions of samples by x-ray diffraction. The method uses ratios of x-ray intensity peaks from a single run. Constants are previously determined for each mineral which is to be quantitatively measured. Ratios of the highest intensity peak of each mineral to be quantified in the sample and the highest intensity peak of a reference mineral contained in the sample are used to calculate sample composition.

Pawloski, G.A.

1984-08-10

154

Ultrafast Structural Dynamics in InSb Probed by Time-Resolved X-Ray Diffraction  

SciTech Connect

Ultrafast structural dynamics in laser-perturbed InSb are studied using time-resolved x-ray diffraction with a novel femtosecond x-ray source. We report the first observation of a delay in the onset of lattice expansion, which we attribute to energy relaxation processes and lattice strain propagation. In addition, we observe direct indications of ultrafast disordering on a subpicosecond time scale. {copyright} {ital 1999} {ital The American Physical Society }

Chin, A.H.; Shank, C.V. [Department of Physics, University of California, Berkeley, California 94720 (United States)] [Department of Physics, University of California, Berkeley, California 94720 (United States); Chin, A.H.; Schoenlein, R.W.; Shank, C.V. [Material Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Material Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Glover, T.E. [Advanced Light Source, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Advanced Light Source, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Leemans, W.P. [Center for Beam Physics, Accelerator and Fusion Research Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Center for Beam Physics, Accelerator and Fusion Research Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Balling, P. [Institute of Physics and Astronomy, University of Aarhus, Ny Munkegade, DK-8000, Aarhus C (Denmark)] [Institute of Physics and Astronomy, University of Aarhus, Ny Munkegade, DK-8000, Aarhus C (Denmark)

1999-07-01

155

Ultrafast Structural Dynamics in InSb Probed by Time-Resolved X-Ray Diffraction  

Microsoft Academic Search

Ultrafast structural dynamics in laser-perturbed InSb are studied using time-resolved x-ray diffraction with a novel femtosecond x-ray source. We report the first observation of a delay in the onset of lattice expansion, which we attribute to energy relaxation processes and lattice strain propagation. In addition, we observe direct indications of ultrafast disordering on a subpicosecond time scale. {copyright} {ital 1999}

A. H. Chin; C. V. Shank; R. W. Schoenlein; T. E. Glover; W. P. Leemans; P. Balling

1999-01-01

156

Femtosecond diffractive imaging with a soft-X-ray free-electron laser  

Microsoft Academic Search

Theory predicts that, with an ultrashort and extremely bright coherent X-ray pulse, a single diffraction pattern may be recorded from a large macromolecule, a virus or a cell before the sample explodes and turns into a plasma. Here we report the first experimental demonstration of this principle using the FLASH soft-X-ray free-electron laser. An intense 25fs, 4×1013Wcm-2 pulse, containing 1012

Henry N. Chapman; Anton Barty; Michael J. Bogan; Sébastien Boutet; Matthias Frank; Stefan P. Hau-Riege; Stefano Marchesini; Bruce W. Woods; Sasa Bajt; W. Henry Benner; Richard A. London; Elke Plönjes; Marion Kuhlmann; Rolf Treusch; Stefan Düsterer; Thomas Tschentscher; Jochen R. Schneider; Eberhard Spiller; Thomas Möller; Christoph Bostedt; Matthias Hoener; David A. Shapiro; Keith O. Hodgson; David van der Spoel; Florian Burmeister; Magnus Bergh; Carl Caleman; Gösta Huldt; M. Marvin Seibert; Filipe R. N. C. Maia; Richard W. Lee; Abraham Szöke; Nicusor Timneanu; Janos Hajdu

2006-01-01

157

Femtosecond Diffractive Imaging with a Soft-X-Ray Free-Electron Laser  

Microsoft Academic Search

Theory predicts that with an ultrashort and extremely bright coherent X-ray pulse, a single diffraction pattern may be recorded from a large macromolecule, a virus, or a cell before the sample explodes and turns into a plasma. Here we report the first experimental demonstration of this principle using the FLASH soft X-ray free-electron laser. An intense 25 fs, 4 x

Bogan; Michael James

2010-01-01

158

Bond-orientational anisotropy in metallic glasses observed by x-ray diffraction  

Microsoft Academic Search

The structural anisotropy in metallic glasses induced by mechanical creep was observed by x-ray diffraction, using energy-dispersive x-ray diffractometry. The creep-induced anisotropy is the origin of the anelasticity in metallic glasses. The structural anisotropy was analyzed in terms of the anisotropic structure factor and anisotropic pair distribution function. The results show that the observed anisotropy is due to the atomic-bond-orientational

Y. Suzuki; J. Haimovich; T. Egami

1987-01-01

159

Time-resolved x-ray photoabsorption and diffraction on timescales from ns to fs  

Microsoft Academic Search

Beamline 7.3.3 at the Advanced Light Source combines a femtosecond laser system with an x-ray streak camera. Time-resolved x-ray diffraction with picosecond time resolution is used to observe scattering from coherent acoustic phonons in laser-excited InSb crystals. Synchrotron radiation pulses of ~300 fs in duration have been generated by femtosecond laser pulses modulating the electron beam in the Advanced Light

P. A. Heimann; T. Missalla; A. Lindenberg; I. Kang; S. Johnson; Z. Chang; H. C. Kapteyn; R. W. Lee; R. W. Falcone; R. W. Schoenlein; T. E. Glover; A. A. Zholents; M. S. Zolotorev; H. A. Padmore

2000-01-01

160

High throughput high resolution Vortex™ detector for X-ray diffraction  

Microsoft Academic Search

Vortex™ is a multicathode drift-type X-ray detector produced from high-purity silicon using state-of-the-art CMOS production technology . Based on the Vortex™ detector, we have developed a compact detector package for X-ray diffraction applications. The spectrometric package contains a 50 mm2 detector cooled using a small Peltier element. The detector package was interfaced with a digital pulse processor, and its performance

J. S. Iwanczyk; B. E. Patt; S. Barkan; L. Feng; C. R. Tull

2003-01-01

161

X-ray diffraction and impedance spectroscopy studies of lithium manganese oxide spinel  

Microsoft Academic Search

Phase transition in lithium manganese oxide spinel synthesized by sol–gel technique and in samples prepared from commercially available powders of LiMn2O4 (Alfa-Aesar and Sigma–Aldrich) was investigated. In addition to the standard impedance measurements and the X-ray diffraction in Bragg–Brentano geometry, simultaneous measurements of impedance spectrum and X-ray pattern in non-focusing geometry were performed in the temperature range between ?25 and

M. Kope?; D. Lisovytskiy; M. Marzantowicz; J. R. Dygas; F. Krok; Z. Kaszkur; J. Pielaszek

2006-01-01

162

The structure of betaxolol from single crystal X-ray diffraction and natural bond orbital analysis  

Microsoft Academic Search

The structure of betaxolol obtained from ethanol:water solution was studied by X-ray diffraction. The geometrical parameters needed to define the structure are tabulated. The X-ray data show the existence of two conformers in the unit cell differing only in the conformation of the cyclopropylmethoxy fragment. Differences in the bond lengths angles and dihedral between both conformations are observed. The cyclopropyl

João Canotilho; Ricardo A. E. Castro; Mário T. S. Rosado; M. Ramos Silva; A. Matos Beja; J. A. Paixão; J. Simões Redinha

2008-01-01

163

Model experiment of in vivo synchrotron X-ray diffraction of human kidney stones  

NASA Astrophysics Data System (ADS)

The diffraction of synchrotron radiation (SR) was used to explore the phase composition of kidney stones placed into a specific object phantom, which imitated the human body. As an imitation of the patient breath, the kidney stone was moved vertically and rotated to an angle of 15° during the recording of the X-ray pattern. It was shown that rotation and displacement did not distort the X-ray pattern.

Ancharov, A. I.; Potapov, S. S.; Moiseenko, T. N.; Feofilov, I. V.; Nizovskii, A. I.

2007-05-01

164

Exploring X-Ray Lines as Scotogenic Signals  

E-print Network

We consider some implications of X-ray lines from certain astronomical objects as potential effects of dark matter decay in the context of the scotogenic model, where neutrinos acquire mass radiatively via one-loop interactions with dark matter. As an example, we focus on the 3.5 keV line recently detected in the X-ray spectra of galaxy clusters, assuming that it stands future scrutiny. We explore the scenario in which the line originates from the slow decay of fermionic dark matter in the model. After obtaining a number of benchmark points representing the parameter space consistent with the new data and various other constraints, we make predictions on several observables in leptonic processes. They include the effective Majorana mass in neutrinoless double-beta decay, the sum of neutrino masses, and the rate of flavor-changing decay mu -> e gamma, as well as the cross sections of e+e- collisions into final states containing nonstandard particles in the model. These are testable in ongoing or future experiments and thus offer means to probe the scotogenic scenario studied.

Gaber Faisel; Shu-Yu Ho; Jusak Tandean

2014-08-25

165

First X-Ray Diffraction Evidence for a Phase Transition during Shock-Wave Compression  

Microsoft Academic Search

The x-ray diffraction pattern of a shock-compressed material which is in the process of undergoing a crystal structure transformation has been observed for the first time. Pyrolytic BN, explosively shocked to 245 kbar, exhibits a diffraction pattern which indicates that the crystal structure during compression is like that of wurtzite.

Quintin Johnson; A. C. Mitchell

1972-01-01

166

Recombination of photodissociated iodine: A time-resolved x-ray-diffraction study  

E-print Network

-ray-diffraction experiment is presented that aims to study the recombination of laser-dissociated iodine molecules dissolvedRecombination of photodissociated iodine: A time-resolved x-ray-diffraction study M. Wulff European. INTRODUCTION The iodine photodissociation and recombination in solu- tions has been studied for 70 years

Ihee, Hyotcherl

167

A large area, 2-D, high-pressure MWPC for wide angle X-ray diffraction  

Microsoft Academic Search

Multi Wire Proportional Counters (MWPCs) possess all the required features for recording X-ray diffraction patterns: large area, high detective quantum efficiency (DQE), low dead time and simultaneous spatial and spectral information. However, their suitability as wide-angle diffraction is compromised by an effect known as parallax broadening. This phenomenon is due to the low density of the gas in the detector,

F. Ortuño-Prados; C. Hall; W. Helsby; A. Jones; R. Lewis; B. Parker; J. Sheldon; A. Bazzano; P. Ubertini

1997-01-01

168

Titration of a Solid Acid Monitored by X-Ray Diffraction  

ERIC Educational Resources Information Center

An experiment is described to introduce students to an important class of solid-state reactions while reinforcing concepts of titration by using a pH meter and a powder X-ray diffractometer. The experiment was successful in teaching students the abstract concepts of solid-state structure and diffraction by applying the diffraction concepts learned…

Dungey, Keenan E.; Epstein, Paul

2007-01-01

169

Elastic constants of fibre-textured thin films determined by X-ray diffraction  

PubMed Central

A new methodology is presented that allows the rapid determination of elastic constants of cubic fibre-textured thin films by X-ray diffraction. The theoretical concept is developed and tested on calculated examples of Cu and CrN films. The mechanical elastic constants are extrapolated from X-ray elastic constants by taking into consideration crystal and macroscopic elastic anisotropy. The derived algorithm enables the determination of a reflection and the corresponding value of the X-ray anisotropic factor ? for which the X-ray elastic constants are equal to their mechanical counterparts in the case of fibre-textured cubic polycrystalline aggregates. The approach is independent of the crystal elastic anisotropy and depends on the fibre-texture type, the texture sharpness, the number of randomly oriented crystallites and the supposed grain-interaction model. In the experimental part, out-of-plane Young’s moduli of 111 and 311 fibre-textured Cu and CrN thin films deposited on monocrystalline Si(100) substrates are determined. The moduli are extrapolated from thin-film experimental X-ray elastic constants that are determined by a combination of X-ray diffraction substrate curvature and sin2? methods. For the calculation, the film macroscopic elastic anisotropy (texture) is considered. The advantage of the new technique lies in the fact that experimental moduli are determined nondestructively, using a static diffraction experiment, and represent volume-averaged quantities. PMID:22477770

Martinschitz, K. J.; Daniel, R.; Mitterer, C.; Keckes, J.

2009-01-01

170

Characterization of ferroelectric ceramics using x-ray diffraction, transmission electron microscopy, and x-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

Ferroelectric ceramic samples of PbTiO3, prepared by a modified oxide-mixing technique, were examined by x-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques for crystalline and microstructural characterization. XRD clearly revealed only a monophasic perovskite of tetragonal symmetry for the reference PbTiO3, which was established to possess both a-a-and a-c-type 90° domains. The inclination was approximately 2° between the two different domains, as observed by high-resolution TEM. Inductively coupled plasma (ICP) analysis, electron probe microanalysis (EPMA), and x-ray photoelectron spectroscopy (XPS) were employed and the ensuing chemical composition results are discussed. The approximate molar ratios of Pb:Ti were 1:1, 1:1.5, and 1:0.8 as obtained by ICP analysis, EPMA, and XPS, respectively. Corrections for the sensitivity factor (SCorr) for Pb 4f, Ti 2p and the substitution of the matrix factors for FTi,Pb, FPb,Ti have been taken into account in obtaining the Pb:Ti ratio of 1:1 by XPS quantification. The sensitivity factor (SKratos) given by the instrumental maker was compared with the theoretical one (STheo) and the result is also discussed.

Kim, Jae-Nam; Shin, Kwang-Soo; Park, Byung-Ok; Lee, Jin-Hong; Kim, Nam-Kyoung; Cho, Sang-Hee

2003-08-01

171

Optomechanical design of a high-precision detector robot arm system for x-ray nano-diffraction with x-ray nanoprobe  

NASA Astrophysics Data System (ADS)

Collaboration between Argonne National Laboratory and Brookhaven National Laboratory has created a design for the high-precision detector robot arm system that will be used in the x-ray nano-diffraction experimental station at the Hard X-ray Nanoprobe (HXN) beamline for the NSLS-II project. The robot arm system is designed for positioning and manipulating an x-ray detector in three-dimensional space for nano-diffraction data acquisition with the HXN x-ray microscope. It consists of the following major component groups: a granite base with air-bearing support, a 2-D horizontal base stage, a vertical axis goniometer, a 2-D vertical plane robot arm, a 3-D fast scanning stages group, and a 2-D x-ray pixel detector. The design specifications and unique optomechanical structure of this novel high-precision detector robot arm system will be presented in this paper.

Shu, D.; Kalbfleisch, S.; Kearney, S.; Anton, J.; Chu, Y. S.

2014-03-01

172

Synchrotron X-Ray Diffraction Studies of Olivine from Comet Wild 2  

NASA Technical Reports Server (NTRS)

We have analyzed a collection of the Comet Wild 2 coma grains returned by the NASA Stardust Mission, using micro-area Laue diffraction equipment. The purpose of the diffraction experiment is to permit the structure refinement of olivine including site occupancies. In addition to the intrinsic importance of the olivine structures for revealing the thermal history of Wild 2 materials, we wish to test reports that olivine recovered after hypervelocity capture in silica aerogel has undergone a basic structural change due to capture heating [1]. The diffraction equipment placed at beam line BL- 4B1 of PF, KEK was developed with a micropinhole and an imaging plate (Fuji Co. Ltd.) using the Laue method combined with polychromatic X-ray of synchrotron radiation operated at energy of 2.5 GeV. The incident beam is limited to 1.6 m in diameter by a micropinhole set just upstream of the sample [2, 3]. It is essential to apply a microbeam to obtain diffracted intensities with high signal to noise ratios. This equipment has been successfully applied to various extraterrestrial materials, including meteorites and interplanetary dust particles [4]. The Laue pattern of the sample C2067,1,111,4 (Fig. 1) was successfully taken on an imaging plate after a 120 minute exposure (Fig. 2).

2008-01-01

173

X-Ray Diffraction Study on the Strain Anisotropy and Dislocation Structure of Deformed Lath Martensite  

NASA Astrophysics Data System (ADS)

18Ni (300) maraging steel possessing lath martensite structure was deformed by four passes of equal-channel angular pressing (ECAP) at ambient temperature. Line profile analysis (LPA) of X-ray diffraction (XRD) patterns identified strong strain anisotropy and remarkable increases in the relative fraction of screw dislocations after ECAP. The strain anisotropy was reasonably accounted for by the anisotropy of elastic constants. Domination of screw dislocations in the deformed structure was attributed to the preferred annihilation of edge dislocations in the early stages of deformation along with the difficulties for annihilation of screw dislocations by cross slipping. Cobalt addition was mainly assumed to make cross slipping difficult by reducing stacking-fault energy and favoring short-range ordering.

Hossein Nedjad, S.; Hosseini Nasab, F.; Movaghar Garabagh, M. R.; Damadi, S. R.; Nili Ahmadabadi, M.

2011-08-01

174

X-ray diffraction study on microstructures of shot/laser-peened AISI316 stainless steel  

NASA Astrophysics Data System (ADS)

Microstructural features of AISI316 stainless steels processed by shot peening (SP) and laser peening (LP) were studied using X-ray diffraction line profile analyses. Both specimens exhibited similar compressive residual stress profiles. Although the number of dislocations was increased and the crystallites were refined with both processes, the dislocation density in the SP specimen was significantly greater than that in the LP specimen. The crystallite size in the SP specimen was one-third that in the LP specimen. The SP process induced martensite transformation. The variations in the microstructural features differed between samples subjected to the two processes. The SP process resulted in a greater variation in the microstructural features in a sample in which residual stresses similar to that induced by the LP process were induced. Thus, the variations in the microstructural features differed depending on the deformation process.

Kumagai, Masayoshi; Akita, Koichi; Itano, Yuta; Imafuku, Muneyuki; Ohya, Shin-ichi

2013-11-01

175

X-ray diffraction from a helix of any length that displays cumulative azimuthal disorder.  

PubMed

An explicit formula has been derived to describe the attenuation and broadening of cylindrically averaged diffraction intensities from a helix of any given length which possesses cumulative azimuthal disorder. The application limits of an approximate formula, represented by the first term of this formula, are defined. Strategies to estimate the length of fibers, the degree of disorder, and the overlap of adjacent layer lines are outlined. Some features of diffraction patterns from the disordered helical structure of the HbS fiber are interpreted in light of these results. In these patterns, non-zero-order Bessel functions are attenuated and broadened due to azimuthal disorder and finite length. Adjacent layer lines overlap because of the very large axial repeat distance of the HbS fibers. As a result, the contribution of any Bessel function term with n > or = 10 is not discernible in these patterns. Only Bessel terms with n < 6 may be accurately estimated in these patterns, if instrumental broadening is negligible or correctable. The theory presented here may also be used to make a rough estimate of the degree of disorder in F-actin fibers by comparison of X-ray diffraction patterns with serial peak projections calculated assuming various degrees of disorder. PMID:9037747

Mu, X Q; Makowski, L; Fairchild, B M

1997-01-01

176

A microstructure reconstruction approach for three dimensional x-ray diffraction microscopy  

NASA Astrophysics Data System (ADS)

Three dimensional X-ray diffraction microscopy (3DXDM) is a set of techniques that can be used to explore the internal structure of polycrystalline materials in a non-destructive way. The microstructure mapping measurements of interest here are carried out at third generation synchrotron sources using high energy, focused x-rays, precision sample positioning hardware, and a high resolution area detector to image diffracted beams. The line focused beam illuminates a planar section of the sample and diffraction patterns are imaged at multiple sample-to-detector distances. The third dimension is probed by translating the sample and measuring successive layers. A variety of reconstruction algorithms for inverting observed data to deduce the microstructure that generated it have been developed but no quantitative maps of microstructure have yet been extracted. In this thesis, a software package that implements a new algorithm is presented and tested. The package uses image analysis for noise reduction and to identify and correlate diffraction spots observed at different sample-to-detector distances. Diffraction spots are back projected into the sample plane. Crystallographic orientation and grain shape are determined from multiple diffracted beams. An area filling growth algorithm determines the edges of individual grains. The program allows fully automatic analysis but also provides for user interactions during the process. Several verification tests are presented. First, simulated data are generated for a simple but non-trivial microstructure and these data are used as input to the program. The software reproduces the correct microstructure within detector digitization errors. We use this test case to study the dependence of reconstruction errors on various mechanical translation stage imperfections, both systematic and statistical. Next, several data sets measuring successively more complex samples are tested. Data were collected by our group and collaborators at beamline XOR-1ID at the Advanced Photon Source. Samples include (i) a single crystal of silicon, (ii) a 20mum diameter gold wire, (iii) an aluminum alloy, Al1050, polycrystal, and (iv) a high purity aluminum polycrystal. While aspects of (i)-(iii) are well reconstructed, the soft high purity sample had broad mosaic structure that prevented the image analysis from identifying distinct diffraction spots. The results described here show that direct inversion of 3DXDM data can be accomplished and can yield important microstructural information. The software presented is, as far as we know, the most successful to date at doing this type of reconstruction.

Xiao, Changshi

177

Exploring X-Ray Lines as Scotogenic Signals  

E-print Network

We consider some implications of X-rays with discrete energies as potential effects of dark matter decay in the context of the scotogenic model, where neutrinos acquire mass radiatively via one-loop interactions with dark matter. As an example, we focus on the 3.5 keV line recently detected in the X-ray spectra of galaxy clusters, assuming that it stands future scrutiny. We explore the scenario in which the line originates from the slow decay of fermionic dark matter in the model. After obtaining a number of benchmark points representing the parameter space consistent with the new data and various other constraints, we make predictions on several observables in leptonic processes. They include the effective Majorana mass in neutrinoless double-beta decay, the sum of neutrino masses, and the rate of flavor-changing decay mu -> e gamma, as well as the cross sections of e+e- collisions into final states containing nonstandard particles in the model. These are testable in ongoing or future experiments and thus of...

Faisel, Gaber; Tandean, Jusak

2014-01-01

178

High Pressure X-Ray Diffraction Studies of Nanocrystalline Materials  

NASA Technical Reports Server (NTRS)

Experimental evidence obtained for a variety of nanocrystalline materials suggest that the crystallographic structure of a very small size particle deviates from that in the bulk crystals. In this paper we show the effect of the surface of nanocrystals on their structure by the analysis of generation and distribution of macro- and micro-strains at high pressures and their dependence on the grain size in nanocrystalline powders of Sic. We studied the structure of Sic nanocrystals by in-situ high-pressure powder diffraction technique using synchrotron and neutron sources and hydrostatic or isostatic pressure conditions. The diffraction measurements were done in HASYLAB at DESY using a Diamond Anvil Cell (DAC) in the energy dispersive geometry in the diffraction vector range up to 3.5 - 4/A and under pressures up to 50 GPa at room temperature. In-situ high pressure neutron diffraction measurements were done at LANSCE in Los Alamos National Laboratory using the HIPD and HIPPO diffractometers with the Paris-Edinburgh and TAP-98 cells, respectively, in the diffraction vector range up to 26 Examination of the response of the material to external stresses requires nonstandard methodology of the materials characterization and description. Although every diffraction pattern contains a complete information on macro- and micro-strains, a high pressure experiment can reveal only those factors which contribute to the characteristic diffraction patterns of the crystalline phases present in the sample. The elastic properties of powders with the grain size from several nm to micrometers were examined using three methodologies: (l), the analysis of positions and widths of individual Bragg reflections (used for calculating macro- and micro-strains generated during densification) [I], (2). the analysis of the dependence of the experimental apparent lattice parameter, alp, on the diffraction vector Q [2], and (3), the atomic Pair Distribution Function (PDF) technique [3]. The results of our studies show, that Sic nanocrystals have the features of two phases, each with its distinct elastic properties. and under pressures up to 8 GPa.

Palosz, B.; Stel'makh, S.; Grzanka, E.; Gierlotka, S.; Palosz, W.

2004-01-01

179

Experimental developments to obtain real-time x-ray diffraction measurements in plate impact experiments  

NASA Astrophysics Data System (ADS)

An experimental facility was developed to obtain real-time, quantitative, x-ray diffraction data in laboratory plate impact experiments. A powder gun, to generate plane wave loading in samples, was designed and built specifically to permit flash x-ray diffraction measurements in shock-compression experiments. Spatial resolution and quality of the diffracted signals were improved significantly over past attempts through partial collimation of the incident beam and the use of two-dimensional detectors to record data from shocked crystals. The experimental configuration and synchronization issues are discussed, and relevant details of the x-ray system and the powder gun are described. Representative results are presented from experiments designed to determine unit cell compression in shock-compressed LiF single crystals subjected to both elastic and elastic-plastic deformation, respectively. The developments described here are expected to be useful for examining lattice deformation and structural changes in shock wave compression studies.

Gupta, Y. M.; Zimmerman, K. A.; Rigg, P. A.; Zaretsky, E. B.; Savage, D. M.; Bellamy, P. M.

1999-10-01

180

Ultrafast X-ray Diffraction of Photodissociation of Iodoform in Solution  

SciTech Connect

We studied structural dynamics in the photodissociation of iodoform (CHI3) dissolved in methanol by time-resolved x-ray diffraction. A femtosecond laser pulse induces the bond-breaking of an iodine atom from iodoform and an x-ray pulse generated from a synchrotron gives time-dependent diffraction signal which contains the structural information of photoproducts with 100 ps time-resolution and 0.001 Aa spatial resolution. CHI2 radical and I atom are formed by the results of the ultrafast photodissociation of iodoform and these intermediates recombine to form iodoform again via geminate recombination. The iodine atoms which escape from the cages nongeminately recombine to form I2. Solvent dynamics, heating and solvent expansion, caused by photodissociation, are also explained from time-resolved x-ray diffraction data.

Lee, Jae Hyuk; Kim, Tae Kyu; Kim, Joonghan; Ihee, Hyotcherl [Department of Chemistry and School of Molecular Science (BK21), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701 (Korea, Republic of); Lorenc, Maciej; Kong, Qingyu; Wulff, Michael [European Synchrotron Radiation Facility, Grenoble Cedex 38043, BP 220 (France)

2007-01-19

181

Coherent x-ray zoom condenser lens for diffractive and scanning microscopy.  

PubMed

We propose a coherent x-ray zoom condenser lens composed of two-stage deformable Kirkpatrick-Baez mirrors. The lens delivers coherent x-rays with a controllable beam size, from one micrometer to a few tens of nanometers, at a fixed focal position. The lens is suitable for diffractive and scanning microscopy. We also propose non-scanning coherent diffraction microscopy for extended objects by using an apodized focused beam produced by the lens with a spatial filter. The proposed apodized-illumination method will be useful in highly efficient imaging with ultimate storage ring sources, and will also open the way to single-shot coherent diffraction microscopy of extended objects with x-ray free-electron lasers. PMID:23609637

Kimura, Takashi; Matsuyama, Satoshi; Yamauchi, Kazuto; Nishino, Yoshinori

2013-04-22

182

X-ray diffraction technique with VISAR support for study of shock-compressed single crystals  

SciTech Connect

A new geometry of X-ray diffraction survey of single crystal in the monochromatic X-ray radiation was used to obtain a diffraction patterns of shock-compressed NaCl single crystals. Shock compression of the 2-mm [100]-oriented single crystals backed with 0.7-mm graphite window was produced by 6-mm Al impactors accelerated up to velocities 320-330 m/sec in 25-mm pneumatic gun. The velocity of the free surface of the graphite window was monitored by VISAR. In two shots the 30-nsec pulse X-ray source was triggered after the arrival of the elastic precursor and the plastic wave front at the NaCl-window interface. No evidence of the transversal strain were found in the diffraction patterns of the shock-compressed NaCl. The material seems to be able to maintain the state of 1-D strain under intensive plastic deformation.

Zaretsky, E. [Pearlstone Center for Aeronautical Engineering Studies, Department of Mechanical Engineering, Ben-Gurion University of the Negev, P.O.Box 653, Beer-Sheva 84105 (Israel)

1998-07-10

183

Signal-to-noise and radiation exposure considerations in conventional and diffraction x-ray microscopy  

PubMed Central

Using a signal-to-noise ratio estimation based on correlations between multiple simulated images, we compare the dose efficiency of two soft x-ray imaging systems: incoherent brightfield imaging using zone plate optics in a transmission x-ray microscope (TXM), and x-ray diffraction microscopy (XDM) where an image is reconstructed from the far-field coherent diffraction pattern. In XDM one must computationally phase weak diffraction signals; in TXM one suffers signal losses due to the finite numerical aperture and efficiency of the optics. In simulations with objects representing isolated cells such as yeast, we find that XDM has the potential for delivering equivalent resolution images using fewer photons. This can be an important advantage for studying radiation-sensitive biological and soft matter specimens. PMID:19654762

Huang, Xiaojing; Miao, Huijie; Steinbrener, Jan; Nelson, Johanna; Shapiro, David; Stewart, Andrew; Turner, Joshua; Jacobsen, Chris

2010-01-01

184

Solid-state /sup 13/C NMR and X-ray diffraction of dermatan sulfate  

SciTech Connect

Dermatan sulfate in the solid state has been studied by /sup 13/C CP/MAS nmr and X-ray diffraction in order to establish the ring conformation of the L-iduronate moiety. The solid state nmr spectrum is similar to the solution spectrum obtained previously, indicating that a ring conformation at least approximating to /sup 1/C/sub 4/ predominates in the solid state. X-ray powder diffraction data from the same sample indicate the presence of the 8-fold helix form previously observed by fiber diffraction, and interpreted in terms of a /sup 4/C/sub 1/ ring form. A likely explanation of the results is that a distorted /sup 1/C/sub 4/ L-iduronate ring conformation, not considered in the initial X-ray analysis, may emerge to provide a satisfactory interpretation of all available physical-chemical data.

Winter, W.T.; Taylor, M.G.; Stevens, E.S.; Morris, E.R.; Rees, D.A.

1986-05-29

185

The 3-dimensional X-ray diffraction microscope: 3D maps of grains and grain dynamics inpolycrystalline materials  

Microsoft Academic Search

Three-Dimensional X-Ray Diffraction (3DXRD) microscopy, an emerging characterisation tool based on high energy synchrotron radiation is presented. The 3DXRD microscope located at the Materials Science beam line at ESRF is dedieated to local mum scale structural characterisation within bulk materials. It is capable of providing information on position, volume, crystallographic orientation, and stress-state of hundreds of embedded grains simultaneously. Furthermore

E. M. Lauridsen; S. F. Nielsen; L. Margulies; S. Schmidt; H. F. Poulsen; D. Juul Jensen

2003-01-01

186

Studies of Materials at the Nanometer Scale Using Coherent X-Ray Diffraction Imaging  

NASA Astrophysics Data System (ADS)

For many years, x-ray microscopy has been attractive for materials studies with its ability to image thick samples and provide nanometer-scale resolution. However, the ability to manufacture high-resolution x-ray optics has been a hurdle to achieving the full potential of diffraction limited x-ray imaging. Recently, the advent of bright and coherent x-ray sources at synchrotrons and x-ray free electron lasers has enabled a lensless imaging technique called coherent diffractive imaging (CDI). Since it was first demonstrated in 1999, CDI has been rapidly developing into a materials imaging technique with resolutions approaching a few nanometers. This review provides an overview of the development of CDI and several applications to nanometer-scale imaging in two and three dimensions of biological and condensed mater materials. Also, we review the development of tabletop, coherent, soft x-ray sources that provide a complimentary and potentially more accessible source for nanometer-scale coherent imaging of materials.

Sandberg, Richard L.; Huang, Zhifeng; Xu, Rui; Rodriguez, Jose A.; Miao, Jianwei

2013-09-01

187

Investigating strongly correlated electron systems with synchrotron X-ray diffraction at LNLS  

Microsoft Academic Search

Recent X-ray diffraction measurements of strongly correlated electron systems performed at the Brazilian synchrotron light laboratory (LNLS) are described. These include the observation, by means of high-resolution powder diffraction, of small structural distortions likely associated with orbital ordering phenomena in transition-metal oxides, and magnetic diffraction of the intermetallic series GdmMnIn3m+2n (M=Rh or Ir). These preliminary results illustrate the opportunities offered

Eduardo Granado

2004-01-01

188

Diffraction-Enhanced Imaging of Musculoskeletal Tissues Using a Conventional X-Ray Tube  

SciTech Connect

DEI based on a conventional x-ray tube allows the visualization of skeletal and soft tissues simultaneously. Although more in-depth testing and optimization of the DEI setup must be carried out, these data demonstrate a proof of principle for further development of the technology for future clinical imaging. In conventional projection radiography, cartilage and other soft tissues do not produce enough radiographic contrast to be distinguishable from each other. Diffraction-enhanced imaging (DEI) uses a monochromatic x-ray beam and a silicon crystal analyzer to produce images in which attenuation contrast is greatly enhanced and x-ray refraction at tissue boundaries can be detected. The aim of this study was to test the efficacy of conventional x-ray tube-based DEI for the detection of soft tissues in experimental samples.

Muehleman, C.; Li, J; Connor, D; Parham, C; Pisano, E; Zhong, Z

2009-01-01

189

Toward atomic resolution diffractive imaging of isolated molecules with x-ray free-electron lasers  

E-print Network

We give a detailed account of the theoretical analysis and the experimental results of an x-ray-diffraction experiment on quantum-state selected and strongly laser-aligned gas-phase ensembles of the prototypical large asymmetric rotor molecule 2,5-diiodobenzonitrile, performed at the Linac Coherent Light Source [Phys. Rev. Lett. 112, 083002 (2014)]. This experiment is the first step toward coherent diffractive imaging of structures and structural dynamics of isolated molecules at atomic resolution, i. e., picometers and femtoseconds, using x-ray free-electron lasers.

Stern, Stephan; Filsinger, Frank; Rouzée, Arnaud; Rudenko, Artem; Johnsson, Per; Martin, Andrew V; Barty, Anton; Bostedt, Christoph; Bozek, John D; Coffee, Ryan N; Epp, Sascha; Erk, Benjamin; Foucar, Lutz; Hartmann, Robert; Kimmel, Nils; Kühnel, Kai-Uwe; Maurer, Jochen; Messerschmidt, Marc; Rudek, Benedikt; Starodub, Dmitri G; Thøgersen, Jan; Weidenspointner, Georg; White, Thomas A; Stapelfeldt, Henrik; Rolles, Daniel; Chapman, Henry N; Küpper, Jochen

2014-01-01

190

Toward atomic resolution diffractive imaging of isolated molecules with X-ray free-electron lasers.  

PubMed

We give a detailed account of the theoretical analysis and the experimental results of an X-ray-diffraction experiment on quantum-state selected and strongly laser-aligned gas-phase ensembles of the prototypical large asymmetric rotor molecule 2,5-diiodobenzonitrile, performed at the Linac Coherent Light Source [Phys. Rev. Lett.112, 083002 (2014)]. This experiment is the first step toward coherent diffractive imaging of structures and structural dynamics of isolated molecules at atomic resolution, i.e., picometers and femtoseconds, using X-ray free-electron lasers. PMID:25415561

Stern, S; Holmegaard, L; Filsinger, F; Rouzée, A; Rudenko, A; Johnsson, P; Martin, A V; Barty, A; Bostedt, C; Bozek, J; Coffee, R; Epp, S; Erk, B; Foucar, L; Hartmann, R; Kimmel, N; Kühnel, K-U; Maurer, J; Messerschmidt, M; Rudek, B; Starodub, D; Thøgersen, J; Weidenspointner, G; White, T A; Stapelfeldt, H; Rolles, D; Chapman, H N; Küpper, J

2014-01-01

191

Nanoscale Imaging of Mineral Crystals inside Biological Composite Materials Using X-Ray Diffraction Microscopy  

NASA Astrophysics Data System (ADS)

We for the first time applied x-ray diffraction microscopy to the imaging of mineral crystals inside biological composite materials—intramuscular fish bone—at the nanometer scale resolution. We identified mineral crystals in collagen fibrils at different stages of mineralization. Based on the experimental results and biomineralization analyses, we suggested a dynamic model to account for the nucleation and growth of mineral crystals in the collagen matrix. The results obtained from this study not only further our understanding of the complex structure of bone, but also demonstrate that x-ray diffraction microscopy will become an important tool to study biological materials.

Jiang, Huaidong; Ramunno-Johnson, Damien; Song, Changyong; Amirbekian, Bagrat; Kohmura, Yoshiki; Nishino, Yoshinori; Takahashi, Yukio; Ishikawa, Tetsuya; Miao, Jianwei

2008-01-01

192

Characterisation of doped-lanthanum gallates by X-ray diffraction and Raman spectroscopy  

Microsoft Academic Search

La1?xSrxGaO3?z (x=0–0.2) and LaGa1?yMyO3?z (y=0–0.2, M=Cr, Mg) were synthesised using the standard solid state technique. The structural changes, with increase in dopant concentration, were investigated using powder X-ray diffraction and Raman spectroscopy. The X-ray diffraction of Sr-doped LaGaO3 shows a shift in the orthorhombic pattern with increase in dopant concentration. At 20 mol% Sr doped on the A-site of LaGaO3

N. M. Sammes; G. A. Tompsett; R. J. Phillips; A. M. Cartner

1998-01-01

193

Phase Sensitive X-Ray Diffraction Imaging of Defects in Biological Macromolecular Crystals  

NASA Technical Reports Server (NTRS)

Characterization of defects and/or disorder in biological macromolecular crystals presents much greater challenges than in conventional small-molecule crystals. The lack of sufficient contrast of defects is often a limiting factor in x-ray diffraction topography of protein crystals. This has seriously hampered efforts to understand mechanisms and origins of formation of imperfections, and the role of defects as essential entities in the bulk of macromolecular crystals. In this report, we employ a phase sensitive x-ray diffraction imaging approach for augmenting the contrast of defects in protein crystals.

Hu, Z. W.; Lai, B.; Chu, Y. S.; Cai, Z.; Mancini, D. C.; Thomas, B. R.; Chernov, A. A.; Curreri, Peter A. (Technical Monitor)

2002-01-01

194

X-ray diffraction study of fluorene, 9-fluorenone, and 9-dicyanomethylenefluorene derivatives  

SciTech Connect

The results of a single-crystal X-ray diffraction analysis of fluorene, 9-fluorenone, and 9-dicyanomethylenefluorene derivatives as individual compounds, as well as their crystal solvates, molecular complexes, and charge-transfer complexes, are generalized. The most interesting features of the molecular geometry and conformation and the molecular packing in the crystals are discussed. The structural formula of 95 compounds and the R factors for X-ray diffraction analysis, which characterize the reliability of determining the structure, are summarized in three tables.

Chetkina, L. A.; Belsky, V. K., E-mail: vkb@rfbr.ru [Karpov Institute of Physical Chemistry (Russian Federation)

2013-01-15

195

Simulating Picosecond X-ray Diffraction from shocked crystals by Post-processing Molecular Dynamics Calculations  

SciTech Connect

Calculations of the x-ray diffraction patterns from shocked crystals derived from the results of Non-Equilibrium-Molecular-Dynamics (NEMD) simulations are presented. The atomic coordinates predicted by the NEMD simulations combined with atomic form factors are used to generate a discrete distribution of electron density. A Fast-Fourier-Transform (FFT) of this distribution provides an image of the crystal in reciprocal space, which can be further processed to produce quantitative simulated data for direct comparison with experiments that employ picosecond x-ray diffraction from laser-irradiated crystalline targets.

Kimminau, G; Nagler, B; Higginbotham, A; Murphy, W; Park, N; Hawreliak, J; Kadau, K; Germann, T C; Bringa, E M; Kalantar, D; Lorenzana, H; Remington, B; Wark, J

2008-06-19

196

X-ray diffraction and nanoindentation studies of nanocrystalline graphite at high pressures  

NASA Astrophysics Data System (ADS)

We report energy dispersive x-ray diffraction studies on nanocrystalline hexagonal graphite samples (average grain size=12 nm) in a diamond-anvil cell to 65 GPa at room temperature. A structural phase transition to a hexagonal diamond phase beginning at 15 GPa is completed at 55 GPa, and is reversible on decompression. The x-ray diffraction studies were followed by nanoindentation hardness measurements on the pressure treated samples. The obtained hardness values are in the range of 1-2 GPa. Unlike fullerenes, the room-temperature compression of nanocrystalline graphite to 65 GPa did not produce a superhard carbon material.

Patterson, J. Reed; Kudryavtsev, Anatoliy; Vohra, Yogesh K.

2002-09-01

197

X-Ray Weak Broad-Line Quasars: Absorption or Intrinsic X-Ray Weakness  

NASA Technical Reports Server (NTRS)

XMM observations of X-ray weak quasars have been performed during 2003. The data for all but the last observation are now available (there has been a delay of several months on the initial schedule, due to high background flares which contaminated the observations: as a consequence, most of them had to be rescheduled). We have reduced and analyzed these data, and obtained interesting preliminary scientific results. Out of the eight sources, 4 are confirmed to be extrimely X-ray weak, in agreement with the results of previous Chandra observations. 3 sources are confirmed to be highly variable both in flux (by factors 20-50) and in spectral properties (dramatic changes in spectral index). For both these groups of objects, an article is in preparation. Preliminary results have been presented at an international workshop on AGN surveys in December 2003, in Cozumel (Mexico). In order to further understand the nature of these X-ray weak quasars, we submitted proposals for spectroscopy at optical and infrared telescopes. We obtained time at the TNG 4 meter telescope for near-IR observations, and at the Hobby-Eberly Telescope for optical high-resolution spectroscopy. These observations will be performed in early 2004, and will complement the XMM data, in order to understand whether the X-ray weakness of these sources is an intrinsic property or is due to absorption by circumnuclear material.

Risaliti, Guido; Mushotzky, Richard F. (Technical Monitor)

2004-01-01

198

An X-ray diffractometer using mirage diffraction  

PubMed Central

Some characteristics are reported of a triple-crystal diffractometer with a (+,??,?+) setting of Si(220) using mirage diffraction. The first crystal is flat, while the second and third crystals are bent. Basically, the first crystal is used as a collimator, the second as a monochromator and the third as the sample. The third crystal also works as an analyzer. The advantages of this diffractometer are that its setup is easy, its structure is simple, the divergence angle from the second crystal is small and the energy resolution of the third crystal is high, of the order of sub-meV. PMID:25242911

Fukamachi, Tomoe; Jongsukswat, Sukswat; Ju, Dongying; Negishi, Riichirou; Hirano, Keiichi; Kawamura, Takaaki

2014-01-01

199

Diffraction crystal for sagittally focusing x-rays  

DOEpatents

The invention is a new type of diffraction crystal designed for sagittally focusing photons of various energies. The invention is based on the discovery that such focusing is not obtainable with conventional crystals because of distortion resulting from anticlastic curvature. The new crystal comprises a monocrystalline base having a front face contoured for sagittally focusing photons and a back face provided with rigid, upstanding, stiffening ribs restricting anticlastic curvature. When mounted in a suitable bending device, the reflecting face of the crystal can be adjusted to focus photons having any one of a range of energies.

Ice, Gene E. (Oak Ridge, TN); Sparks, Jr., Cullie J. (Oak Ridge, TN)

1984-01-01

200

Diffraction crystals for sagittally focusing x-rays  

DOEpatents

The invention is a new type of diffraction crystal designed for sagittally focusing photons of various energies. The invention is based on the discovery that such focusing is not obtainable with conventional crystals because of distortion resulting from anticlastic curvature. The new crystal comprises a monocrystalline base having a front face contoured for sagittally focusing photons and a back face provided with rigid, upstanding, stiffening ribs restricting anticlastic curvature. When mounted in a suitable bending device, the reflecting face of the crystal can be adjusted to focus photons having any one of a range of energies.

Ice, G.E.; Sparks, C.J. Jr.

1982-06-07

201

Characterization of an Yb:LuVO 4 single crystal using X-ray topography, high-resolution X-ray diffraction, and X-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

Knowledge on the defect and electronic structure allows for improved modeling of material properties. A short literature review has shown that the information on defect structure of rare earth orthovanadate single crystals is limited. In this paper, defect and electronic structure of a needle-shaped Yb:LuVO 4 single crystal grown by the slow cooling method have been studied by means of X-ray diffraction topography employing white synchrotron beam, high-resolution diffraction (HRD) and photoelectron spectroscopy (XPS) techniques. Topographic investigations show that the crystal is composed of two blocks disoriented by about 1.5° and separated by a narrow deformed region. Some contrasts observed within the crystal volume may be attributed to glide bands and sector boundaries. The contrasts appearing in the vicinity of the surface may be interpreted as due to the presence of small inclusions. The HRD study indicates, in particular, that among point defects, the vacancy type defects dominate and that the density of other defects is small in comparison. The XPS measurements enabled, despite highly insulating properties of the studied crystal, an analysis of its bulk electronic structure, including the main core-levels (O 1 s, V 2 p, Lu 4 f) as well as the valence band range.

Paszkowicz, W.; Romanowski, P.; B?k-Misiuk, J.; Wierzchowski, W.; Wieteska, K.; Graeff, W.; Iwanowski, R. J.; Heinonen, M. H.; Ermakova, O.; D?bkowska, H.

2011-10-01

202

Normalization schemes for ultrafast x-ray diffraction using a table-top laser-driven plasma source  

SciTech Connect

We present an experimental setup of a laser-driven x-ray plasma source for femtosecond x-ray diffraction. Different normalization schemes accounting for x-ray source intensity fluctuations are discussed in detail. We apply these schemes to measure the temporal evolution of Bragg peak intensities of perovskite superlattices after ultrafast laser excitation.

Schick, D.; Bojahr, A.; Herzog, M. [Institut fuer Physik and Astronomie, Universitaet Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam (Germany); Korff Schmising, C. von [Institut fuer Optik und Atomare Physik, Technische Universitaet Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany); Shayduk, R.; Leitenberger, W.; Gaal, P.; Bargheer, M. [Helmholtz Zentrum Berlin, Albert-Einstein-Strasse 15, 12489 Berlin (Germany)

2012-02-15

203

An X-ray Fourier line shape analysis in cold-worked hexagonal zirconium  

Microsoft Academic Search

Detailed Fourier analysis of line shapes has been carried out in hexagonal zirconium metal in the cold-worked and partially recovered states. X-ray diffraction profiles from the fault-unaffected 10.0, 00.2, 11.0, 11.2 and 00.4 and fault-affected 10.1, 10.3, 20.1, 10.2 and 20.2 reflections have been recorded using a counter diffractometer for this purpose. The line shape analysis has shown small anisotropy

S. K. Chatterjee; S. P. Sen Gupta

1974-01-01

204

Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium  

E-print Network

Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium online xxxx Keywords: Amorphous calcium carbonate; EPSR modelling; Neutron diffraction; X-ray diffraction Amorphous calcium carbonate (ACC) plays a key role in biomineralisation processes in sea organisms. Neutron

Benning, Liane G.

205

Effect of hydrostatic pressure on the crystal structure of sodium oxalate: X-ray diffraction study and ab initio simulations  

E-print Network

Effect of hydrostatic pressure on the crystal structure of sodium oxalate: X-ray diffraction study diffraction structure analysis / X-ray diffraction / Sodium oxalate Abstract. Effect of hydrostatic pressures isosymmetric first-order phase transition without hysteresis occurred. The orienta- tion of the oxalate anions

Oganov, Artem R.

206

Experimental comparison of parametric X-ray radiation and diffracted bremsstrahlung in a pyrolytic graphite crystal  

NASA Astrophysics Data System (ADS)

Spectral characteristics of diffracted bremsstrahlung (DB) and parametric X-ray radiation (PXR), that can be treated as a diffraction of the own field of a charged particle moving through a crystal, were measured under similar experimental conditions. The target used was a pyrolytic graphite crystal with a mosaic factor of ˜3 mrad. It is shown that for the thickness of a mosaic graphite target ˜0.01 rad length and ?? ??p, the contribution from diffraction of real photons into spectrum measured is comparable with that from PXR. For DB, the yield ratio falls well within the diffraction theory of X-rays in mosaic crystals, taking into account the effect of suppression of bremsstrahlung. For PXR, the yield ratio may be satisfactory explained following the kinematic theory, taking into account the PXR photon diffraction and correlation between DB and PXR intensity.

Chefonov, O. V.; Kalinin, B. N.; Naumenko, G. A.; Padalko, D. V.; Potylitsyn, A. P.; Vnukov, I. E.; Endo, I.; Inoue, M.

2001-01-01

207

Multiple-Wave Diffraction in High Energy Resolution Back-Reflecting X-Ray Optics  

SciTech Connect

We have studied the effects of multiple-wave diffraction in a novel optical scheme recently published by Shvyd'ko et al. utilizing Bragg diffraction of x rays in backscattering geometry from asymmetrically cut crystals for achieving energy resolutions beyond the intrinsic width of the Bragg reflection. By numerical simulations based on dynamic x-ray diffraction and by experimentation involving two-dimensional angular scans of the back-reflecting crystal, multiple-wave diffraction was found to contribute up to several tens percent loss of efficiency but can be avoided without degrading the energy resolution of the original scheme by careful choice of azimuthal orientation of the diffracting crystal surface and by tilting of the crystal perpendicular to the dispersion plane.

Stetsko, Yuri P.; Keister, J. W.; Coburn, D. S.; Kodituwakku, C. N.; Cunsolo, A.; Cai, Y. Q. [National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2011-10-07

208

Single-shot femtosecond x-ray diffraction from randomly oriented ellipsoidal nanoparticles  

NASA Astrophysics Data System (ADS)

Coherent diffractive imaging of single particles using the single-shot “diffract and destroy” approach with an x-ray free electron laser (FEL) was recently demonstrated. A high-resolution low-noise coherent diffraction pattern, representative of the object before it turns into a plasma and explodes, results from the interaction of the FEL with the particle. Iterative phase retrieval algorithms are used to reconstruct two-dimensional projection images of the object from the recorded intensities alone. Here we describe the first single-shot diffraction data set that mimics the data proposed for obtaining 3D structure from identical particles. Ellipsoidal iron oxide nanoparticles (250nm×50nm) were aerosolized and injected through an aerodynamic lens stack into a soft x-ray FEL. Particle orientation was not controlled with this injection method. We observed that, at the instant the x-ray pulse interacts with the particle, a snapshot of the particle’s orientation is encoded in the diffraction pattern. The results give credence to one of the technical concepts of imaging individual nanometer and subnanometer-sized objects such as single molecules or larger clusters of molecules using hard x-ray FELs and will be used to help develop robust algorithms for determining particle orientations and 3D structure.

Bogan, M. J.; Boutet, S.; Barty, A.; Benner, W. H.; Frank, M.; Lomb, L.; Shoeman, R.; Starodub, D.; Seibert, M. M.; Hau-Riege, S. P.; Woods, B.; Decorwin-Martin, P.; Bajt, S.; Schulz, J.; Rohner, U.; Iwan, B.; Timneanu, N.; Marchesini, S.; Schlichting, I.; Hajdu, J.; Chapman, H. N.

2010-09-01

209

Single-Shot Femtosecond X-ray Diffraction from Randomly Oriented Ellipsoidal Nanoparticles  

SciTech Connect

Coherent diffractive imaging of single particles using the single-shot 'diffract and destroy' approach with an x-ray free electron laser (FEL) was recently demonstrated. A high-resolution low-noise coherent diffraction pattern, representative of the object before it turns into a plasma and explodes, results from the interaction of the FEL with the particle. Iterative phase retrieval algorithms are used to reconstruct two-dimensional projection images of the object from the recorded intensities alone. Here we describe the first single-shot diffraction data set that mimics the data proposed for obtaining 3D structure from identical particles. Ellipsoidal iron oxide nanoparticles (250 nm x 50 nm) were aerosolized and injected through an aerodynamic lens stack into a soft x-ray FEL. Particle orientation was not controlled with this injection method. We observed that, at the instant the x-ray pulse interacts with the particle, a snapshot of the particle's orientation is encoded in the diffraction pattern. The results give credence to one of the technical concepts of imaging individual nanometer and subnanometer-sized objects such as single molecules or larger clusters of molecules using hard x-ray FELs and will be used to help develop robust algorithms for determining particle orientations and 3D structure.

Bogan, M.J.; /SLAC; Boutet, S.; /SLAC; Barty, A.; /LLNL, Livermore /DESY; Benner, W.H.; Frank, M.; /LLNL, Livermore; Lomb, L.; Shoeman, R.; /Heidelberg, Max Planck Inst. Med. Res. /CFEL, Hamburg; Starodub, D.; /SLAC; Seibert, M.M.; /Uppsala U.; Hau-Riege, S.P.; Woods, B.; /LLNL, Livermore; Decorwin-Martin, P.; /SLAC; Bajt, S.; /DESY; Schulz, J.; /DESY; Rohner, U.; /LLNL, Livermore /Unlisted, CH; Iwan, B.; Timneanu, N.; /Uppsala U.; Marchesini, S.; /LBL, Berkeley; Schlichting, I.; /Heidelberg, Max Planck Inst. Med. Res. /CFEL, Hamburg; Hajdu, J.; /Uppsala U.; Chapman, H.N.; /DESY /Hamburg U., Inst. Theor. Phys. II

2012-04-18

210

A Numerical Study on X-Ray Diffraction Effects within Objects  

SciTech Connect

X-rays, being waves, always undergo the propagation effects of reflection, refraction, diffraction, geometric attenuation and absorption. In most circumstances the first four effects are considered negligible given the resolution sizes demanded of the measurement systems, x-ray energies involved, and physical properties of the materials under evaluation. We have reached the point, however, in some x-ray non-destructive evaluation (NDE) and imaging where we wish to resolve features of micrometer size in millimeter size objects to less than micrometer resolution. Given this resolution and the sizes of the measurement systems, diffraction effects within the object may become observable. We studied the extent to which diffraction is observable numerically using a two-dimensional paraxial approximation wave propagation code using a multislice method. We modeled realistic parts of interest at worst-case x-ray energies, comparing wave propagation and straight-ray simulated results. In two cases, we compare the numerical results to experimental measurements. The conclusion, based upon the results of the simulation code, is that diffraction effects on the measured data will be insignificant. However, we demonstrate by a single example, that in certain cases diffraction effects may be significant.

Lehman, S K

2005-09-29

211

Line Searches in Swift X-ray Spectra  

E-print Network

Prior to the launch of the Swift mission several X-ray line detections were reported in Gamma Ray Burst afterglow spectra. To date, these pre-Swift era results have not been conclusively confirmed. The most contentious issue in this area is the choice of statistical method used to evaluate the significance of these features. In this paper we compare three different methods already extant in the literature for assessing the significance of possible line features and discuss their relative advantages and disadvantages. The methods are demonstrated by application to observations of 40 bursts from the archive of Swift XRT at early times (< few ks post trigger in the rest frame of the burst). Based on this thorough analysis we found no strong evidence for emission lines. For each of the three methods we have determined detection limits for emission line strengths in bursts with spectral parameters typical of the Swift-era sample. We also discuss the effects of the current calibration status on emission line detection.

C. P. Hurkett; S. Vaughan; J. P. Osborne; P. T. O'Brien; K. L. Page; A. Beardmore; O. Godet; D. N. Burrows; M. Capalbi; P. Evans; N. Gehrels; M. R. Goad; J. E. Hill; J. Kennea; T. Mineo; M. Perri; R. Starling

2008-02-04

212

Hydrothermal formation of tobermorite studied by in situ X-ray diffraction under autoclave condition.  

PubMed

Hydrothermal formation of tobermorite from a pre-cured cake has been investigated by transmission X-ray diffraction (XRD) using high-energy X-rays from a synchrotron radiation source in combination with a newly designed autoclave cell. The autoclave cell has a large and thin beryllium window for wide-angle X-ray diffraction; nevertheless, it withstands a steam pressure of more than 1.2 MPa, which enables in situ XRD measurements in a temperature range of 373 to 463 K under a saturated steam pressure. Formation and/or decomposition of several components has been successfully observed during 7.5 h of reaction time. From the intensity changes of the intermediate materials, namely non-crystalline C-S-H and hydroxylellestadite, two pathways for tobermorite formation have been confirmed. Thus, the newly developed autoclave cell can be used for the analyses of reaction mechanisms under specific atmospheres and temperatures. PMID:19713643

Kikuma, Jun; Tsunashima, Masamichi; Ishikawa, Tetsuji; Matsuno, Shin-ya; Ogawa, Akihiro; Matsui, Kunio; Sato, Masugu

2009-09-01

213

Spectrometer for hard X-ray free-electron laser based on diffraction focusing.  

PubMed

X-ray free-electron lasers (XFELs) generate sequences of ultra-short spatially coherent pulses of X-ray radiation. A diffraction focusing spectrometer (DFS), which is able to measure the whole energy spectrum of the radiation of a single XFEL pulse with an energy resolution of ?E/E 2 × 10(-6), is proposed. This is much better than for most modern X-ray spectrometers. Such resolution allows one to resolve the fine spectral structure of the XFEL pulse. The effect of diffraction focusing occurs in a single-crystal plate due to dynamical scattering, and is similar to focusing in a Pendry lens made from a metamaterial with a negative refraction index. Such a spectrometer is easier to operate than those based on bent crystals. It is shown that the DFS can be used in a wide energy range from 5 keV to 20 keV. PMID:23412482

Kohn, V G; Gorobtsov, O Y; Vartanyants, I A

2013-03-01

214

X-ray diffraction study of structural stability of giant proteoglycan molecules of mucus  

NASA Astrophysics Data System (ADS)

X-ray diffraction study of various native and modified gastrointestinal mucins was carried out using synchrotron radiation. The mucus X-ray patterns of mammals and invertebrates are very similar and display a large number of sharp diffraction rings at the spacing of about 4.65 nm, which are due to the helical packing of polysaccharide chains covalently connected to the protein core. A comparative analysis of the X-ray patterns obtained earlier by us from various samples of mucus and biological tissues showed that the 4.65(±0.15) nm spacing is a nanoscale structural invariant of giant proteoglycan molecules of both the mucus and the extracellular matrix of tissues. A role of structural dynamics of proteoglycan scaffolding of biological systems in mechanism of modifying adaptation of organisms to significant changes of temperature is discussed.

Vazina, A. A.; Lanina, N. F.; Vasilieva, A. A.; Korneev, V. N.; Zabelin, A. V.; Polyakova, E. P.

2009-05-01

215

Cryogenic x-ray diffraction microscopy utilizing high-pressure cryopreservation  

NASA Astrophysics Data System (ADS)

We present cryo x-ray diffraction microscopy of high-pressure-cryofixed bacteria and report high-convergence imaging with multiple image reconstructions. Hydrated D. radiodurans cells were cryofixed at 200 MPa pressure into ˜10-?m-thick water layers and their unstained, hydrated cellular environments were imaged by phasing diffraction patterns, reaching sub-30-nm resolutions with hard x-rays. Comparisons were made with conventional ambient-pressure-cryofixed samples, with respect to both coherent small-angle x-ray scattering and the image reconstruction. The results show a correlation between the level of background ice signal and phasing convergence, suggesting that phasing difficulties with frozen-hydrated specimens may be caused by high-background ice scattering.

Lima, Enju; Chushkin, Yuriy; van der Linden, Peter; Kim, Chae Un; Zontone, Federico; Carpentier, Philippe; Gruner, Sol M.; Pernot, Petra

2014-10-01

216

Dynamical diffraction theory for the parametric X-rays and coherent bremsstrahlung  

NASA Astrophysics Data System (ADS)

The various mechanisms of X-ray radiation from relativistically charged particles in a crystal are analyzed from a common point of view, based on quantum electrodynamics in a medium. Parametric X-rays (PXR), diffraction radiation (DR) and coherent bremsstrahlung (CB) lead to different contributions to the amplitude of the radiation process but because of their interference they cannot be considered separately in the radiation intensity. The role of the dynamical diffraction effects and the coherent bremsstrahlung is considered to be dependent on the crystal parameters and particle energy. The conception of the high resolution parametric X-rays (HRPXR) is introduced and the universal radiation distribution, which can simplify the analysis of the results for this case is also considered. The possible applications of HRPXR are discussed.

Feranchuk, I.; Lugovskaya, O.; Ulyanenkov, A.

2005-05-01

217

Perspective: Structural dynamics in condensed matter mapped by femtosecond x-ray diffraction  

NASA Astrophysics Data System (ADS)

Ultrashort soft and hard x-ray pulses are sensitive probes of structural dynamics on the picometer length and femtosecond time scales of electronic and atomic motions. Recent progress in generating such pulses has initiated new directions of condensed matter research, exploiting a variety of x-ray absorption, scattering, and diffraction methods to probe photoinduced structural dynamics. Atomic motion, changes of local structure and long-range order, as well as correlated electron motion and charge transfer have been resolved in space and time, providing a most direct access to the physical mechanisms and interactions driving reversible and irreversible changes of structure. This perspective combines an overview of recent advances in femtosecond x-ray diffraction with a discussion on ongoing and future developments.

Elsaesser, T.; Woerner, M.

2014-01-01

218

Residual stress measurement using X-ray diffraction  

E-print Network

that exhibit a linear behavior as in the case of a homogenous isotropic sample in a biaxial stress state is included. The plot of d vs. 2? is a straight line which slope is proportional to stress. On the other hand, the second set of samples showed... is in compression then the planes are further apart than in the stress-free state because of Poisson?s ratio. The interplanar spacing ?d? is obtained from the peak in intensity versus scattering angle and Bragg?s law...

Anderoglu, Osman

2005-02-17

219

X-ray diffraction and x-ray absorption studies of porous silicon, siloxene, heat-treated siloxene, and layered polysilane  

Microsoft Academic Search

Several porous silicon, siloxene (Si6H6O3), heat-treated siloxene, and layered polysilane (Si6H6) samples have been studied with K- and L-edge x-ray photoabsorption, photoemission, and powder x-ray diffraction. The x-ray absorption of layered polysilane and porous-Si are found to be remarkably similar. In particular, the K absorption edges of these samples shift by about 0.4–0.6 eV to higher energy relative to crystalline

J. R. Dahna; E. W. Fuller; W. J. Weydanz; J. S. Tse; D. D. Klug; T. Van Buuren; T. Tiedje

1994-01-01

220

Synchrotron X-ray Powder Diffraction Studies in Pulsed Magnetic Fields  

SciTech Connect

X-ray powder diffraction experiments under pulsed magnetic fields were carried out at the DUBBLE beamline (BM26B) at the ESRF. A mobile generator delivered 110kJ to the magnet coil, which was sufficient to generate peak fields of 30T. A liquid He flow cryostat allowed us to vary the sample temperature accurately between 8K and 300K.

Detlefs, C. [European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble (France); Frings, P.; Duc, F.; Nardone, M.; Billette, J.; Zitouni, A.; Rikken, G. L. J. A. [Laboratoire National des Champs Magnetiques Pulses, 143, avenue de Rangueil, F-31400 Toulouse (France); Vanacken, J. [Laboratoire National des Champs Magnetiques Pulses, 143, avenue de Rangueil, F-31400 Toulouse (France); Pulsveldengroep, Institute for Nanoscale Physics and Chemistry, Celestijnenlaan 200 D, B-3001 Leuven (Belgium); Lorenzo, J. E. [Laboratoire de Cristallographie, CNRS, B.P. 166X, F-38043 Grenoble (France); Bras, W. [Netherlands Organisation for Scientific Research (NWO), DUBBLE CRG at ESRF, BP 220, F-38043 Grenoble (France)

2007-01-19

221

Structural investigation of porcine stomach mucin by X-ray fiber diffraction and homology modeling  

SciTech Connect

Research highlights: {yields} Techniques to get oriented mucin fibre. {yields} X-ray fibre diffraction pattern for mucin. {yields} Molecular modeling of mucin based on X-ray fibre diffraction pattern. -- Abstract: The basic understanding of the three dimensional structure of mucin is essential to understand its physiological function. Technology has been developed to achieve orientated porcine stomach mucin molecules. X-ray fiber diffraction of partially orientated porcine stomach mucin molecules show d-spacing signals at 2.99, 4.06, 4.22, 4.7, 5.37 and 6.5 A. The high intense d-spacing signal at 4.22 A is attributed to the antiparallel {beta}-sheet structure identified in the fraction of the homology modeled mucin molecule (amino acid residues 800-980) using Nidogen-Laminin complex structure as a template. The X-ray fiber diffraction signal at 6.5 A reveals partial organization of oligosaccharides in porcine stomach mucin. This partial structure of mucin will be helpful in establishing a three dimensional structure for the whole mucin molecule.

Veluraja, K., E-mail: veluraja@msuniv.ac.in [Department of Physics, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu 627012 (India); Vennila, K.N. [CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, Tamilnadu 600025 (India)] [CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, Tamilnadu 600025 (India); Umamakeshvari, K.; Jasmine, A. [Department of Physics, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu 627012 (India)] [Department of Physics, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu 627012 (India); Velmurugan, D. [CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, Tamilnadu 600025 (India)] [CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, Tamilnadu 600025 (India)

2011-03-25

222

Mineralogy by X-ray Diffraction on Mars: The Chemin Instrument on Mars Science Laboratory  

NASA Technical Reports Server (NTRS)

To obtain detailed mineralogy information, the Mars Science Laboratory rover Curiosity carries CheMin, the first X-ray diffraction (XRD) instrument used on a planet other than Earth. CheMin has provided the first in situ XRD analyses of full phase assemblages on another planet.

Vaniman, D. T.; Bristow, T. F.; Bish, D. L.; Ming, D. W.; Blake, D. F.; Morris, R. V.; Rampe, E. B.; Chipera, S. J.; Treiman, A. H.; Morrison, S. M.; Achilles, C. N.; Downs, R. T.; Farmer, J. D.; Crisp, J. A.; Morookian, J. M.; Des Marais, D. J.; Grotzinger, J. P.; Sarrazin, P.; Yen, A. S.

2014-01-01

223

Synchrotron X-ray diffraction characterization of healthy and fluorotic human dental enamel  

NASA Astrophysics Data System (ADS)

With the introduction of fluoride as the main anticaries agent used in preventive dentistry, and perhaps an increase in fluoride in our food chain, dental fluorosis has become an increasing world-wide problem. Visible signs of fluorosis begin to become obvious on the enamel surface as opacities, implying some porosity in the tissue. The mechanisms that conduct the formation of fluorotic enamel are unknown, but should involve modifications in the basic physical-chemistry reactions of demineralization and remineralisation of the enamel of the teeth, which is the same reaction of formation of the enamel's hydroxyapatite (HAp) in the maturation phase. The increase of the amount of fluoride inside of the apatite will result in gradual increase of the lattice parameters. The aim of this work is to characterize the healthy and fluorotic enamel in human tooth using Synchrotron X-ray diffraction. All the scattering profile measurements were carried out at the X-ray diffraction beamline (XRD1) at the Brazilian Synchrotron Light Laboratory—LNLS, Campinas, Brazil. X-ray diffraction experiments were performed both in powder samples and polished surfaces. The powder samples were analyzed to obtain the characterization of a typical healthy enamel pattern. The polished surfaces were analyzed in specific areas that have been identified as fluorotic ones. X-ray diffraction data were obtained for all samples and these data were compared with the control samples and also with the literature data.

Colaço, M. V.; Barroso, R. C.; Porto, I. M.; Gerlach, R. F.; Costa, F. N.; Braz, D.; Droppa, R.; de Sousa, F. B.

2012-10-01

224

Residual stress evaluation and fatigue life prediction in the welded joint by x-ray diffraction  

NASA Astrophysics Data System (ADS)

In the fossil power plant, the reliability of the components which consist of the many welded parts depends on the quality of welding. The residual stress is occurred by the heat flux of high temperature during weld process. This decreases the mechanical properties as the strength of fatigue and fracture. The residual stress of the welded part in the recently constructed power plants has been the cause of a variety of accidents. The objective of this study is measurement of the residual stress and the full width at half maximum intensity (FWHM) by X-ray diffraction method and to estimate the feasibility of this application for fatigue life assessment of the high-temperature pipeline. The materials used for the study is P92 steel for the use of high temperature pipe on super critical condition. The test results were analyzed by the distributed characteristics of residual stresses and FWHM in x-ray diffraction intensity curve. Also, X-ray diffraction tests using specimens simulated low cycle fatigue damage were performed in order to analyze fatigue properties when fatigue damage conditions become various stages. As a result of X-ray diffraction tests for specimens simulated fatigue damages, we conformed that the ratio of the FWHM due to fatigue damage has linear relationship with fatigue life ratio algebraically. From this relationship, it was suggested that direct expectation of the life consumption rate was feasible.

Yoo, Keun Bong; Hwang, Kwon Tae; Chang, Jung Chel; Kim, Jae Hoon

2009-07-01

225

Parametric X-ray Radiation and Diffraction Bremsstrahlung from Moderately Relativistic Electrons in Pyrolytic Graphite Crystal  

NASA Astrophysics Data System (ADS)

Spectral maxima of parametric X-ray radiation (PXR) and diffraction bremsstrahlung (DBS) from moderately relativistic electrons and bremsstrahlung interacting with crystal have been observed. The maxima position of PXR and DBS depends on the crystal orientation angle and corresponds to theoretical calculations.

Vagner, A. R.; Potylitsyn, A. P.; Kuznecov, S. I.; Uglov, S. R.; Zabaev, V. N.; Razin, S. V.

2007-11-01

226

X-RAY POWDER DIFFRACTION SYSTEM FOR CHEMICAL SPECIATION OF PARTICULATE AEROSOL SAMPLES  

EPA Science Inventory

An x-ray powder diffraction system has been developed for the automated measurement and analysis of particulate aerosol samples. The system is optimized to process samples with particle loadings of about 100 micrograms/sq cm which are acquired with dichotomous air samplers. A pos...

227

X-Ray Diffraction Study of L2005 AG17 (IDPs) by Using SR  

NASA Technical Reports Server (NTRS)

X-ray diffraction study revealed the existence of magnetite and new type of pyrrhotite with the chemical formula of Fe0.56S in L2005 AG17. Considering the total chemical formula of Fe0.83S, residual iron in amorphous state might exist in this sample. Additional information is contained in the original extended abstract.

Ohsumi, K. O.; Hagiya, K. H.; Zolensky, M. E.

2002-01-01

228

High spatial resolution X-ray and gamma ray imaging system using diffraction crystals  

DOEpatents

A method and a device for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation are provided. The device comprises a plurality of arrays, with each array comprising a plurality of elements comprising a first collimator, a diffracting crystal, a second collimator, and a detector.

Smither, Robert K. (Hinsdale, IL)

2011-05-17

229

X-ray diffraction study of crystalline phases of calcium sulphate in alginate impression materials.  

PubMed

In the present study the crystalline phases of calcium sulphate present in various commercially available alginate impression materials were identified by means of x-ray diffraction. The diffractograms obtained indicated that the predominant crystalline phase in most materials was calcium sulphate dihydrate and confirmed the presence of calcium sulphate hemihydrate in some products. PMID:9021340

Anastassiadou, V; Dolopoulou, V; Kaloyannides, A

1996-01-01

230

QUANTITATIVE X-RAY POWDER DIFFRACTION ANALYSIS OF AIR PARTICULATE SAMPLES  

EPA Science Inventory

The design, operation and calibration of an x-ray powder diffraction system for the analysis of air particulate samples are described. The instrument analyzes a sample non-destructively for its major crystalline components. The system has been optimized for the non-destructive an...

231

Influence of X-Ray Diffraction Sample Preparation on Quantitative Mineralogy: Implications for Chromate Waste Treatment  

Microsoft Academic Search

Powders of chromite ore processing residue (COPR) were mineral- ogically evaluated using quantitative X-ray powder diffraction (XRPD) to illustrate the impacts of sample preparation procedures. Chromite ore processing residue is strongly alkaline, reactive, contains minerals of varying hardness and absorption coefficients, and exhibits signifi- cant amorphicity. This posesa challenge to produce powdersfor XRPD analysis that are sufficiently fine and of

Dimitris Dermatas; Maria Chrysochoou; Sarra Pardali; Dennis G. Grubb

232

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

E-print Network

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

Paris-Sud XI, Université de

233

Raman and x-ray diffraction study on the material property of oxyfluoride vitroceramics  

Microsoft Academic Search

Upconversion study is imperative now to find good material that has high laser damage threshold, good physics and chemical property, easy in processing in order to develop various up- conversion applications. This paper studies the material property of oxyfluoride vitroceramics by Raman and x-ray diffraction spectroscopy. It reveals the physical reason why the Er3+ ion's upconversion luminescence in oxyfluoride vitroceramics

Xiaobo Chen; N. Sawanobori; Yulong Liu

2000-01-01

234

An Inquiry Based Exercise Using X-ray Diffraction Data to Incite Student Learning  

NASA Astrophysics Data System (ADS)

An inquiry based learning exercise was designed for an upper division advanced inorganic laboratory course that meets one of the requirements for the Bachelor of Science degree in Chemistry and Biochemistry at the University of California, Santa Cruz. The content goals of this exercise were evaluation of whether a given solid state structure was previously known by using powder X-ray diffraction data, and understanding how the diffraction pattern relates to the crystal structure of the compound in question. The scientific process goals included searching a database to match the patterns and preparing data for oral presentations. The goals of the exercise were addressed via an activity allowing students to utilize real X-ray powder diffraction data to search and match with known structures in a database (International Crystal Structure Database) and to give an oral presentation. After students found their structures in the database, they prepared oral presentations justifying their choice for the match and their reasoning through structural analysis of the X-ray data. Students learned about X-ray diffraction theory in an inquiry type environment and gained valuable experience and confidence in presenting their findings using strong reasoning and communication skills. Assessment was implemented during active facilitation throughout the activity and during the final oral presentations.

Rogow, D. L.; McDonald, W.; Bresler, M. R.

2010-12-01

235

Energy-tunable x-ray diffraction: A tool for depth profiling in polycrystalline materials  

NASA Astrophysics Data System (ADS)

We have developed a new variant of depth-sensitive x-ray diffraction technique to study structural parameters in inhomogeneous polycrystalline materials. In this method, diffraction patterns are measured at different x-ray energies which are varied by small steps, and then the depth-resolved structural characteristics are retrieved from the energy-dependent x-ray diffraction data. In the current articles, this approach is applied to extract preferred orientation with depth resolution. In the case of uniaxial preferred orientation, the analytical algorithm has been developed based on March functions. Application of this technique to seashells allowed us to characterize the microstructure evolution in the nacre layer. Near the inner surface, adjacent to the mollusk mantle, the nacre consists of well-defined lamellas which reveal a high degree of the (001)-preferred orientation. This preferred orientation deteriorates in depth due to the accumulation of cracks and other imperfections. The texture distribution is characterized quantitatively by depth-dependent March parameters, which allows us to compare samples taken from different shells. In a similar way, energy-variable x-ray diffraction can be used for nondestructive characterization of a very broad spectrum of laminated structures and composite materials and systems.

Zolotoyabko, E.; Quintana, J. P.

2002-03-01

236

DSC AND X-RAY DIFFRACTION INVESTIGATIONS OF PHASE TRANSITIONS IN HxBABA AND NBABA  

E-print Network

DSC AND X-RAY DIFFRACTION INVESTIGATIONS OF PHASE TRANSITIONS IN HxBABA AND NBABA K. USHA DENIZ, A studied by DSC in the temperature range, -- 100 °C to 300 °C. A scheme of tran- sitions has been proposed Scanning Calorimetry (DSC). Several hitherto un- known phases have been found to occur above room

Paris-Sud XI, Université de

237

High Pressure Studies Using Energy Dispersive Diffraction of High Energy X-Rays.  

National Technical Information Service (NTIS)

The smooth continuum of white radiation produced by a 160 kV generator has been combined with Energy Dispersive X Ray Diffraction (EDXRD) and a Drickamer type cell for high pressure studies. The theory of EDXRD is briefly reviewed and the advantages of th...

W. F. Sherman, D. Haeusermann

1987-01-01

238

Structural Order-Disorder Transformations Monitored by X-Ray Diffraction and Photoluminescence  

ERIC Educational Resources Information Center

A study was conducted to examine the structural order-disorder transformation promoted by controlled heat treatment using X-ray diffraction technique (XRD) and photoluminescence (PL) techniques as tools to monitor the degree of structural order. The experiment was observed to be versatile and easily achieved with low cost which allowed producing…

Lima, R. C.; Paris, E. C.; Leite, E. R.; Espinosa, J. W. M.; Souza, A. G.; Longo, E.

2007-01-01

239

Quantitative 3D imaging of whole, unstained cells by using X-ray diffraction microscopy  

E-print Network

and structure of cellular organelles including cell wall, vacuole, endoplasmic reticulum, mitochondria, granulesQuantitative 3D imaging of whole, unstained cells by using X-ray diffraction microscopy Huaidong of cells. Cryoelectron micro- scopy can image pleomorphic structures at a resolution of 3­5 nm, but is only

Miao, Jianwei "John"

240

Investigation of nanostructured Fe 3 O 4 polypyrrole core-shell composites by X-ray absorbtion spectroscopy and X-ray diffraction using synchrotron radiation  

Microsoft Academic Search

In this article, we focus on the structural peculiarities of nanosized Fe3O4 in the core-shell nanocomposites obtained by polymerization of conducting polypyrrole shell around Fe3O4 nanoparticles. The local structure of Fe atoms was determined from the Extended X-ray Absorption Fine Structure analysis\\u000a using our own package computer programs. An X-ray diffraction method that is capable to determine average particle size,

Nicolae Aldea; Rodica Turcu; Alexandrina Nan; Izabella Craciunescu; Ovidiu Pana; Xie Yaning; Zhonghua Wu; Doina Bica; Ladislau Vekas; Florica Matei

2009-01-01

241

Applications of Synchrotron-Based X-Ray Diffraction and X-Ray Absorption Spectroscopy to the Understanding of Poorly Crystalline and Metal-Substituted Iron Oxides  

Microsoft Academic Search

The octahedral site in iron oxides has been shown to undergo changes in its occupation when iron oxides form in the presence of single and multiple foreign metals in controlled laboratory settings as well as the natural environment. X-ray absorption spectroscopy coupled with the increased precision of synchrotron-based X-ray diffraction (SXRD) have shed new light on important basic mechanisms controlling

Balwant Singh; Markus Gräfe; Navdeep Kaur; Andrea Liese

2010-01-01

242

Powder x-ray diffraction procedures for the Mound aging\\/surveillance program. [Lead styphnate; hexanitroazobenzene  

Microsoft Academic Search

Power x-ray diffraction procedures were developed and utilized for routine analysis of samples containing lead styphnate, hexanitroazobenzene and mixtures of titanium hydride and potassium perchlorate, in support of the aging\\/surveillance program at Mound. Diffraction data were collected with an automated Rigaku wide-angle powder diffractometer under remote control of a DEC PDP-11\\/44 computer that was connected to it with optical wave

D. B. Sullenger; E. F. Jendrek; B. L. Sorrell

1985-01-01

243

X-Ray-Diffraction Topographic Studies of Magnetic-Domain Configurations in Terbium Iron Garnet  

Microsoft Academic Search

The method of x-ray-diffraction topography, which is briefly described is applied to the study of magnetic domains in a single-crystal sample of Tb3Fe5O12. Comparison is made with the same domain structure observed by transmitted polarized light and Bitter patterns, and a general interpretation of the diffraction topograph is suggested. Finally, the possible applications of the technique, particularly with respect to

J. Basterfield; M. J. Prescott

1967-01-01

244

Time-resolved x-ray photoabsorption and diffraction on timescales from ns to fs  

Microsoft Academic Search

Time-resolved x-ray diffraction with picosecond time resolution is used to observe scattering from coherent acoustic phonons in laser-excited InSb crystals. The observed oscillations in the crystal reflectivity are in agreement with a model based on dynamical diffraction theory. Synchrotron radiation pulses of ~300 fs in duration have been generated by femtosecond laser pulses modulating the electron beam in the Advanced

Philip A. Heimann; Thomas Missalla; Aaron M. Lindenberg; Inuk Kang; S. Johnson; Z. Chang; H. C. Kapteyn; R. W. Lee; Roger W. Falcone; Robert E. Schoenlein; Thornton E. Glover; Alexander A. Zholents; Max Zolotorev; Howard A. Padmore

2000-01-01

245

X-Ray Diffraction Measurements of Silver during Slow Heating to the Melting Point  

Microsoft Academic Search

Measurements of the x-ray lattice parameter, the Bragg diffraction peak intensity, and the diffraction peak width were made during the very slow quasiequilibrium heating of high purity silver (99.999+% pure) to the point where melting was observed. Back-reflection measurements were made using a ?;422? reflection from a small homogeneously heated single crystal region under conditions allowing continuous visual observation of

D. R. Beaman; R. W. Balluffi; R. O. Simmons

1964-01-01

246

The energy calibration of x-ray absorption spectra using multiple-beam diffraction  

SciTech Connect

A new method for calibrating the energy scale of x-ray absorption spectra from an energy dispersive spectrometer has been developed. Distinct features in the diffracted intensity of the curved silicon crystal monochromator have been assigned to multiple-beam diffraction. The photon energies of these structures can be calculated if the precise spacing of the diffracting planes and the orientation of the crystal relative to the incident synchrotron radiation are known. The evaluation of Miller indices of operative reflections and the calculation of the corresponding photon energy is presented. The assignment of operative reflexes is simplified if the monochromator crystal can be rotated around the main diffracting vector {bold H}.

Hagelstein, M.; Cunis, S. (Fachhochschule Ostfriesland, Constantiaplatz 4, D-2970 Emden (Germany)); Frahm, R. (Hamburger Synchrotronstrahlungslabor HASYLAB at DESY, Notkestrasse 85, D-2000 Hamburg 52 (Germany)); Rabe, P. (Fachhochschule Ostfriesland, Constantiaplatz 4, D-2970 Emden (Germany))

1992-01-01

247

X-ray diffraction pattern of a Gulyaev-Bleustein surface acoustic wave in grazing geometry  

SciTech Connect

The X ray diffraction pattern of a Gulyaev-Bleustein surface acoustic wave (SAW) under grazing angles of incidence in noncoplanar symmetric Laue geometry has been considered. It is supposed that the propagation direction of an SAW makes a small angle with the diffraction vector. It is shown that small deviations from the Bragg angle ({approx}0.01'' induced by the SAW and do not affect the reflection coefficient lead to the formation of diffraction satellites both in the cases of standing and traveling SAWs. It has been established that the recorded diffraction pattern, which is a time-averaged intensity distribution, has characteristic profiles for odd and even satellites.

Levonyan, L. V., E-mail: gurgen@iapp.sci.am; Khachaturyan, G. K. [Academy of Sciences of Armenia, Institute of Applied Physics Problems (Armenia)

2006-12-15

248

The catalytic mechanism of an aspartic proteinase explored with neutron and X-ray diffraction  

SciTech Connect

Hydrogen atoms play key roles in enzyme mechanism, but as this study shows, even high-quality X-ray data to a resolution of 1 {angstrom} cannot directly visualize them. Neutron diffraction, however, can locate deuterium atoms even at resolutions around 2 {angstrom}. Both neutron and X-ray diffraction data have been used to investigate the transition state of the aspartic proteinase endothiapepsin. The different techniques reveal a different part of the story, revealing the clearest picture yet of the catalytic mechanism by which the enzyme operates. Room temperature neutron and X-ray diffraction data were used in a newly developed joint refinement software package to visualize deuterium atoms within the active site of the enzyme when a gem-diol transition state analogue inhibitor is bound at the active site. These data were also used to estimate their individual occupancy, while analysis of the differences between the bond lengths of the catalytic aspartates was performed using atomic resolution X-ray data. The two methods are in agreement on the protonation state of the active site with a transition state analogue inhibitor bound confirming the catalytic mechanism at which the enzyme operates.

Kovalevsky, Andrey [Los Alamos National Laboratory (LANL); Erskine, Peter T. [University of Southampton, England; Cooper, Jon [University of Southampton, England

2008-01-01

249

A laboratory based system for Laue micro x-ray diffraction  

SciTech Connect

A laboratory diffraction system capable of illuminating individual grains in a polycrystalline matrix is described. Using a microfocus x-ray source equipped with a tungsten anode and prefigured monocapillary optic, a micro-x-ray diffraction system with a 10 mum beam was developed. The beam profile generated by the ellipsoidal capillary was determined using the"knife edge" approach. Measurement of the capillary performance, indicated a beam divergence of 14 mrad and a useable energy bandpass from 5.5 to 19 keV. Utilizing the polychromatic nature of the incident x-ray beam and application of the Laue indexing software package X-Ray Micro-Diffraction Analysis Software, the orientation and deviatoric strain of single grains in a polycrystalline material can be studied. To highlight the system potential the grain orientation and strain distribution of individual grains in a polycrystalline magnesium alloy (Mg 0.2 wt percent Nd) was mapped before and after tensile loading. A basal (0002) orientation was identified in the as-rolled annealed alloy; after tensile loading some grains were observed to undergo an orientation change of 30 degrees with respect to (0002). The applied uniaxial load was measured as an increase in the deviatoric tensile strain parallel to the load axis (37 References).

Advanced Light Source; Tamura, Nobumichi; Lynch, P.A.; Stevenson, A.W.; Liang, D.; Parry, D.; Wilkins, S.; Tamura, N.

2007-02-28

250

Thermal transport in thin films measured by time-resolved, grazing incidence x-ray diffraction.  

SciTech Connect

We use depth- and time-resolved x-ray diffraction to study thermal transport across single crystal Bi films grown on sapphire in order to determine the thermal conductivity of the film and the Kapitza conductance of the interface. Ultrafast Ti:sapphire laser pulses were used to heat the films; x-ray diffraction then measured the film's lattice expansion. Use of grazing incidence diffraction geometry provided depth sensitivity, as the x-ray angle of incidence was varied near the critical angle. The shift of the film's Bragg peak position with time was used to determine the film temperature averaged over an x-ray penetration depth that could be selected by choice of the angle of incidence. For films that were thick compared to the laser penetration depth, we observed a large temperature gradient at early times. In this case, measurements with the incident angle near or well above the critical angle were more sensitive to the film conductivity or Kapitza conductance, respectively. For thinner films, however, cooling was dominated by the Kapitza conductance at all accessible time scales.

Walko, D. A.; Sheu, Y.-M.; Trigo, M.; Reis, D. A. (X-Ray Science Division); (Univ. of Michigan,); (SLAC National Accelerator Lab.); (Stanford Univ.)

2011-01-01

251

Femtosecond X-ray line emission from multilayer targets irradiated by short laser pulses  

Microsoft Academic Search

The invention of high-power, ultra-short-pulse lasers has opened the way to investigations aimed at the creation of a new type of bright X-ray source for various uses including material science applications and time-resolved X-ray diffraction for biology. The efficiency with which laser energy incident on a solid target is converted into an X-ray emission depends on many factors, including the

H. Nakano; A. A. Andreev; J. Limpouch

2004-01-01

252

Serial femtosecond X-ray diffraction of 30S ribosomal subunit microcrystals in liquid suspension at ambient temperature using an X-ray free-electron laser  

PubMed Central

High-resolution ribosome structures determined by X-ray crystallography have provided important insights into the mechanism of translation. Such studies have thus far relied on large ribosome crystals kept at cryogenic temperatures to reduce radiation damage. Here, the application of serial femtosecond X-ray crystallography (SFX) using an X-ray free-electron laser (XFEL) to obtain diffraction data from ribosome microcrystals in liquid suspension at ambient temperature is described. 30S ribosomal subunit microcrystals diffracted to beyond 6?Å resolution, demonstrating the feasibility of using SFX for ribosome structural studies. The ability to collect diffraction data at near-physiological temperatures promises to provide fundamental insights into the structural dynamics of the ribosome and its functional complexes. PMID:23989164

Demirci, Hasan; Sierra, Raymond G.; Laksmono, Hartawan; Shoeman, Robert L.; Botha, Sabine; Barends, Thomas R. M.; Nass, Karol; Schlichting, Ilme; Doak, R. Bruce; Gati, Cornelius; Williams, Garth J.; Boutet, Sébastien; Messerschmidt, Marc; Jogl, Gerwald; Dahlberg, Albert E.; Gregory, Steven T.; Bogan, Michael J.

2013-01-01

253

Investigations into rapid uniaxial compression of polycrystalline targets using femtosecond X-ray diffraction  

NASA Astrophysics Data System (ADS)

Although the pressures achievable in laser experiments continue to increase, the mechanisms underlying how solids deform at high strain rates are still not well understood. In particular, at higher pressures, the assumption that the difference between the longitudinal and transverse strains in a sample remains small becomes increasingly invalid. In recent years, there has been an increasing interest in simulating compression experiments on a granular level. In situ X-ray diffraction, where a target is probed with X-rays while a shock is propagating through it, is an excellent tool to test these simulations. We present data from the first long-pulse laser experiment at the MEC instrument of LCLS, the world's first hard X-ray Free Electron Laser, demonstrating large strain anisotropies. From this we infer shear stresses in polycrystalline copper of up to 1.75 GPa at a shock pressure of 32 GPa.

McGonegle, David; Higginbotham, Andrew; Galtier, Eric; McBride, Emma E.; McMahon, Malcolm I.; Milathianaki, Despina; Lee, Hae Ja; Nagler, Bob; Vinko, Sam M.; Wark, Justin S.

2014-05-01

254

Femtosecond x-ray photoelectron diffraction on gas-phase dibromobenzene molecules  

NASA Astrophysics Data System (ADS)

We present time-resolved femtosecond photoelectron momentum images and angular distributions of dissociating, laser-aligned 1,4-dibromobenzene (C6H4Br2) molecules measured in a near-infrared pump, soft-x-ray probe experiment performed at an x-ray free-electron laser. The observed alignment dependence of the bromine 2p photoelectron angular distributions is compared to density functional theory calculations and interpreted in terms of photoelectron diffraction. While no clear time-dependent effects are observed in the angular distribution of the Br(2p) photoelectrons, other, low-energy electrons show a pronounced dependence on the time delay between the near-infrared laser and the x-ray pulse.

Rolles, D.; Boll, R.; Adolph, M.; Aquila, A.; Bostedt, C.; Bozek, J. D.; Chapman, H. N.; Coffee, R.; Coppola, N.; Decleva, P.; Delmas, T.; Epp, S. W.; Erk, B.; Filsinger, F.; Foucar, L.; Gumprecht, L.; Hömke, A.; Gorkhover, T.; Holmegaard, L.; Johnsson, P.; Kaiser, Ch; Krasniqi, F.; Kühnel, K.-U.; Maurer, J.; Messerschmidt, M.; Moshammer, R.; Quevedo, W.; Rajkovic, I.; Rouzée, A.; Rudek, B.; Schlichting, I.; Schmidt, C.; Schorb, S.; Schröter, C. D.; Schulz, J.; Stapelfeldt, H.; Stener, M.; Stern, S.; Techert, S.; Thøgersen, J.; Vrakking, M. J. J.; Rudenko, A.; Küpper, J.; Ullrich, J.

2014-06-01

255

Analyzing solution-phase time-resolved x-ray diffraction data by isolated-solute models  

E-print Network

Analyzing solution-phase time-resolved x-ray diffraction data by isolated-solute models Jae Hyuk Extracting transient structural information of a solute from time-resolved x-ray diffraction TRXD data is not trivial because the signal from a solution contains not only the solute-only term as in the gas phase

Ihee, Hyotcherl

256

Machine learning for ultrafast X-ray diffraction patterns on large-scale GPU clusters  

E-print Network

The classical method of determining the atomic structure of complex molecules by analyzing diffraction patterns is currently undergoing drastic developments. Modern techniques for producing extremely bright and coherent X-ray lasers allow a beam of streaming particles to be intercepted and hit by an ultrashort high energy X-ray beam. Through machine learning methods the data thus collected can be transformed into a three-dimensional volumetric intensity map of the particle itself. The computational complexity associated with this problem is very high such that clusters of data parallel accelerators are required. We have implemented a distributed and highly efficient algorithm for inversion of large collections of diffraction patterns targeting clusters of hundreds of GPUs. With the expected enormous amount of diffraction data to be produced in the foreseeable future, this is the required scale to approach real time processing of data at the beam site. Using both real and synthetic data we look at the scaling ...

Ekeberg, Tomas; Liu, Jing

2014-01-01

257

Direct Modeling of X-Ray Diffraction Pattern from Contracting Skeletal Muscle  

PubMed Central

A direct modeling approach was used to quantitatively interpret the two-dimensional x-ray diffraction patterns obtained from contracting mammalian skeletal muscle. The dependence of the calculated layer line intensities on the number of myosin heads bound to the thin filaments, on the conformation of these heads and on their mode of attachment to actin, was studied systematically. Results of modeling are compared to experimental data collected from permeabilized fibers from rabbit skeletal muscle contracting at 5°C and 30°C and developing low and high isometric tension, respectively. The results of the modeling show that: i), the intensity of the first actin layer line is independent of the tilt of the light chain domains of myosin heads and can be used as a measure of the fraction of myosin heads stereospecifically attached to actin; ii), during isometric contraction at near physiological temperature, the fraction of these heads is ?40% and the light chain domains of the majority of them are more perpendicular to the filament axis than in rigor; and iii), at low temperature, when isometric tension is low, a majority of the attached myosin heads are bound to actin nonstereospecifically whereas at high temperature and tension they are bound stereospecifically. PMID:18539638

Koubassova, Natalia A.; Bershitsky, Sergey Y.; Ferenczi, Michael A.; Tsaturyan, Andrey K.

2008-01-01

258

Dynamical X-ray Diffraction from In x Ga1- x As Heterostructures with Dislocations  

NASA Astrophysics Data System (ADS)

High-resolution x-ray diffraction is an important nondestructive tool for structural characterization of semiconductor heterostructures, and the diffraction intensity profiles contain information on the depth profiles of strain, composition, and defect densities in device heterostructures. Much of this information remains inaccessible because the lack of phase information prevents direct inversion of the rocking curves. The current practice is to use dynamical simulations in conjunction with a curve-fitting procedure to indirectly extract the profiles of strain and composition, but such dynamical simulations have been based on perfect, dislocation-free laminar crystals, which renders the analysis inapplicable to highly mismatched structures containing dislocation densities greater than about 106 cm-2. In this work we present a dynamical model for Bragg x-ray diffraction in semiconductor device structures with nonuniform composition, strain, and dislocation density, which is based on the Takagi-Taupin equation for distorted crystals and accounts for the diffuse scattering arising from the strain mosaicity and angular mosaicity associated with dislocations. We show theoretically that the x-ray diffraction profiles from In x Ga1- x As/GaAs (001) heterostructures are strongly affected by the depth distribution of the dislocation density as well as the composition and strain, so that in principle all three distributions may be obtained by the analysis of the measured diffraction profiles.

Rago, P. B.; Ayers, J. E.

2013-08-01

259

The Diffraction of X-Rays by Gas Molecules A Comparison with Electron Diffraction and a Discussion of the Results for SiHCl3  

Microsoft Academic Search

The principles of x-ray and electron diffraction by free molecules are discussed in view of the application of these methods to the determination of molecular structures. The influence of the chemical bond is not more disturbing for x-ray measurements than for electron measurements. The hydrogen atoms are practically nonexistent for x-ray diffraction while it is not so for electron diffraction.

Maurice Henri Pirenne

1939-01-01

260

Quantitative Analysis of the Resolved X-ray Emission Line Profiles of O Stars  

E-print Network

Quantitative Analysis of the Resolved X-ray Emission Line Profiles of O Stars David Cohen.swarthmore.edu/~cohen/presentations/CfA_11jun07.pdf #12;1. Chandra spectra: emission lines are broad and asymmetric 2. Hot-star X-rays in context 3. Hot-star winds 4. Emission line shapes: constraints on hot plasma distribution and wind mass

Cohen, David

261

Study of properties of chemically modified samples of halloysite mineral with X-ray fluorescence and X-ray powder diffraction methods  

NASA Astrophysics Data System (ADS)

Elemental and chemical composition of raw and activated samples of halloysite mineral using wavelength dispersive X-ray fluorescence (WDXRF), total reflection X-ray fluorescence (TXRF) and X-ray powder diffraction (XRPD) methods were determined. As the result, it has been shown that application of the complementary X-ray spectrometry techniques allows very precise observation of changes in composition of halloysite mineral samples caused by its chemical modifications. Sample preparation procedure and usability of the research methods applied are described in details. Procedure of activation of raw halloysite mineral samples by etching them in sulfuric acid of various concentrations has been described and discussed. The ability of the samples to adsorb lead from intentionally contaminated water was tested and confirmed.

Bana?, D.; Kubala-Kuku?, A.; Braziewicz, J.; Majewska, U.; Pajek, M.; Wudarczyk-Mo?ko, J.; Czech, K.; Garnuszek, M.; S?omkiewicz, P.; Szczepanik, B.

2013-12-01

262

Small-angle x-ray scattering/diffraction system for studies of biological and other materials at the Stanford Synchrotron Radiation Laboratory (abstract)  

SciTech Connect

A versatile small-angle x-ray diffraction/scattering system has been developed at Stanford Synchrotron Radiation Laboratory for studies of biological and other materials. The system includes two sets of collimation slits separated by an ionization chamber, a sample holder cooled by a circulation bath, a vacuum/He scattering path after the sample holder and a detector, either a linear one-dimensional position-sensitive proportional counter or a position-sensitive quadrant detector. Data aquisition is controlled by a VAXstation through a CAMAC interface. Menu-driven data acquisition and on-line analysis software has been developed. The system can be used to collect small- to intermediate-angle x-ray scattering and diffraction data. Monochromatic, anomalous, and time-resolved diffraction/scattering experiments are possible. A time-resolved spectrophotometer using photodiode arrays has also been developed for simultaneous measurements of optical absorption spectra and x-ray scattering/diffraction.

Wakatsuki, S.; Hodgson, K.O. (Department of Chemistry, Stanford University, Stanford, California 94305 (United States)); Eliezer, D. (Department of Physics, Stanford University, Stanford, California 94305 (United States)); Rice, M. (Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)); Hubbard, S.; Gillis, N.; Doniach, S. (Department of Applied Physics, Stanford University, Stanford, California 94305 (United States)); Spann, U. (Stanford Synchrotron Radiation Laboratory, California 94205 (United States))

1992-01-01

263

X-Ray Continua of Broad Absorption Line Quasars  

NASA Technical Reports Server (NTRS)

The targets for this program, PG1416-129 and LBQS 2212-1759 were known to be Broad Absorption Line Quasars (BALQSOs). BALQSOs are highly absorbed in soft X-rays. Good high energy response of Rossi-XTE made them ideal targets for observation. We observed LBQS 2212-1759 with PCA. We have now analyzed the data and found that the source was not detected. Since our target was expected to be faint, reliable estimate of background was very important. With the release of new FTOOLS (version 4.1) we were able to do so. We also analyzed a well known bright object and verified our results with the published data. This gave us confidence in the non-detection of our target LBQS 2212-1759. We are currently investigating the implications of this non-detection. Due to some scheduling problems, our second target PG1416-129 was not observed in A01. It was observed on 06/26/98. This target was detected with RXTE. We are now working on the spectral analysis with XSPEC.

Mathur, S.

1999-01-01

264

In-line phase-contrast imaging based on Tsinghua Thomson scattering x-ray source.  

PubMed

Thomson scattering x-ray sources can produce ultrashort, energy tunable x-ray pulses characterized by high brightness, quasi-monochromatic, and high spatial coherence, which make it an ideal source for in-line phase-contrast imaging. We demonstrate the capacity of in-line phase-contrast imaging based on Tsinghua Thomson scattering X-ray source. Clear edge enhancement effect has been observed in the experiment. PMID:25173262

Zhang, Zhen; Du, Yingchao; Yan, Lixin; Hua, Jianfei; Yang, Jin; Xiao, Yongshun; Huang, Wenhui; Chen, Huaibi; Tang, Chuanxiang

2014-08-01

265

In-line phase-contrast imaging based on Tsinghua Thomson scattering x-ray source  

NASA Astrophysics Data System (ADS)

Thomson scattering x-ray sources can produce ultrashort, energy tunable x-ray pulses characterized by high brightness, quasi-monochromatic, and high spatial coherence, which make it an ideal source for in-line phase-contrast imaging. We demonstrate the capacity of in-line phase-contrast imaging based on Tsinghua Thomson scattering X-ray source. Clear edge enhancement effect has been observed in the experiment.

Zhang, Zhen; Du, Yingchao; Yan, Lixin; Hua, Jianfei; Yang, Jin; Xiao, Yongshun; Huang, Wenhui; Chen, Huaibi; Tang, Chuanxiang

2014-08-01

266

Optimal mapping of x-ray laser diffraction patterns into three dimensions using routing algorithms.  

PubMed

Coherent diffractive imaging with x-ray free-electron lasers (XFEL) promises high-resolution structure determination of noncrystalline objects. Randomly oriented particles are exposed to XFEL pulses for acquisition of two-dimensional (2D) diffraction snapshots. The knowledge of their orientations enables 3D imaging by multiview reconstruction, combining 2D diffraction snapshots in different orientations. Here we introduce a globally optimal algorithm that can infer these orientations. We apply it to experimental XFEL data of nanoparticles and so determine their 3D electron density. PMID:24229216

Kassemeyer, Stephan; Jafarpour, Aliakbar; Lomb, Lukas; Steinbrener, Jan; Martin, Andrew V; Schlichting, Ilme

2013-10-01

267

Self-terminating diffraction gates femtosecond X-ray nanocrystallography measurements  

NASA Astrophysics Data System (ADS)

X-ray free-electron lasers have enabled new approaches to the structural determination of protein crystals that are too small or radiation-sensitive for conventional analysis. For sufficiently short pulses, diffraction is collected before significant changes occur to the sample, and it has been predicted that pulses as short as 10 fs may be required to acquire atomic-resolution structural information. Here, we describe a mechanism unique to ultrafast, ultra-intense X-ray experiments that allows structural information to be collected from crystalline samples using high radiation doses without the requirement for the pulse to terminate before the onset of sample damage. Instead, the diffracted X-rays are gated by a rapid loss of crystalline periodicity, producing apparent pulse lengths significantly shorter than the duration of the incident pulse. The shortest apparent pulse lengths occur at the highest resolution, and our measurements indicate that current X-ray free-electron laser technology should enable structural determination from submicrometre protein crystals with atomic resolution.

Barty, Anton; Caleman, Carl; Aquila, Andrew; Timneanu, Nicusor; Lomb, Lukas; White, Thomas A.; Andreasson, Jakob; Arnlund, David; Bajt, Saša; Barends, Thomas R. M.; Barthelmess, Miriam; Bogan, Michael J.; Bostedt, Christoph; Bozek, John D.; Coffee, Ryan; Coppola, Nicola; Davidsson, Jan; Deponte, Daniel P.; Doak, R. Bruce; Ekeberg, Tomas; Elser, Veit; Epp, Sascha W.; Erk, Benjamin; Fleckenstein, Holger; Foucar, Lutz; Fromme, Petra; Graafsma, Heinz; Gumprecht, Lars; Hajdu, Janos; Hampton, Christina Y.; Hartmann, Robert; Hartmann, Andreas; Hauser, Günter; Hirsemann, Helmut; Holl, Peter; Hunter, Mark S.; Johansson, Linda; Kassemeyer, Stephan; Kimmel, Nils; Kirian, Richard A.; Liang, Mengning; Maia, Filipe R. N. C.; Malmerberg, Erik; Marchesini, Stefano; Martin, Andrew V.; Nass, Karol; Neutze, Richard; Reich, Christian; Rolles, Daniel; Rudek, Benedikt; Rudenko, Artem; Scott, Howard; Schlichting, Ilme; Schulz, Joachim; Seibert, M. Marvin; Shoeman, Robert L.; Sierra, Raymond G.; Soltau, Heike; Spence, John C. H.; Stellato, Francesco; Stern, Stephan; Strüder, Lothar; Ullrich, Joachim; Wang, X.; Weidenspointner, Georg; Weierstall, Uwe; Wunderer, Cornelia B.; Chapman, Henry N.

2012-01-01

268

Feasibility of imaging living cells at subnanometer resolutions by ultrafast X-ray diffraction.  

PubMed

Detailed structural investigations on living cells are problematic because existing structural methods cannot reach high resolutions on non-reproducible objects. Illumination with an ultrashort and extremely bright X-ray pulse can outrun key damage processes over a very short period. This can be exploited to extend the diffraction signal to the highest possible resolution in flash diffraction experiments. Here we present an analysis of the interaction of a very intense and very short X-ray pulse with a living cell, using a non-equilibrium population kinetics plasma code with radiation transfer. Each element in the evolving plasma is modeled by numerous states to monitor changes in the atomic populations as a function of pulse length, wavelength, and fluence. The model treats photoionization, impact ionization, Auger decay, recombination, and inverse bremsstrahlung by solving rate equations in a self-consistent manner and describes hydrodynamic expansion through the ion sound speed. The results show that subnanometer resolutions could be reached on micron-sized cells in a diffraction-limited geometry at wavelengths between 0.75 and 1.5 nm and at fluences of 1011-1012 photons microm-2 in less than 10 fs. Subnanometer resolutions could also be achieved with harder X-rays at higher fluences. We discuss experimental and computational strategies to obtain depth information about the object in flash diffraction experiments. PMID:19079804

Bergh, Magnus; Huldt, Gösta; Tîmneanu, Nicusor; Maia, Filipe R N C; Hajdu, Janos

2008-01-01

269

Bayesian orientation estimate and structure information from sparse single-molecule x-ray diffraction images  

NASA Astrophysics Data System (ADS)

We developed a Bayesian method to extract macromolecular structure information from sparse single-molecule x-ray free-electron laser diffraction images. The method addresses two possible scenarios. First, using a "seed" structural model, the molecular orientation is determined for each of the provided diffraction images, which are then averaged in three-dimensional reciprocal space. Subsequently, the real space electron density is determined using a relaxed averaged alternating reflections algorithm. In the second approach, the probability that the "seed" model fits to the given set of diffraction images as a whole is determined and used to distinguish between proposed structures. We show that for a given x-ray intensity, unexpectedly, the achievable resolution increases with molecular mass such that structure determination should be more challenging for small molecules than for larger ones. For a sufficiently large number of recorded photons (>200) per diffraction image an M1/6 scaling is seen. Using synthetic diffraction data for a small glutathione molecule as a challenging test case, successful determination of electron density was demonstrated for 20000 diffraction patterns with random orientations and an average of 82 elastically scattered and recorded photons per image, also in the presence of up to 50% background noise. The second scenario is exemplified and assessed for three biomolecules of different sizes. In all cases, determining the probability of a structure given set of diffraction patterns allowed successful discrimination between different conformations of the test molecules. A structure model of the glutathione tripeptide was refined in a Monte Carlo simulation from a random starting conformation. Further, effective distinguishing between three differently arranged immunoglobulin domains of a titin molecule and also different states of a ribosome in a tRNA translocation process was demonstrated. These results show that the proposed method is robust and enables structure determination from sparse and noisy x-ray diffraction images of single molecules spanning a wide range of molecular masses.

Walczak, Micha?; Grubmüller, Helmut

2014-08-01

270

Bayesian orientation estimate and structure information from sparse single-molecule x-ray diffraction images.  

PubMed

We developed a Bayesian method to extract macromolecular structure information from sparse single-molecule x-ray free-electron laser diffraction images. The method addresses two possible scenarios. First, using a "seed" structural model, the molecular orientation is determined for each of the provided diffraction images, which are then averaged in three-dimensional reciprocal space. Subsequently, the real space electron density is determined using a relaxed averaged alternating reflections algorithm. In the second approach, the probability that the "seed" model fits to the given set of diffraction images as a whole is determined and used to distinguish between proposed structures. We show that for a given x-ray intensity, unexpectedly, the achievable resolution increases with molecular mass such that structure determination should be more challenging for small molecules than for larger ones. For a sufficiently large number of recorded photons (>200) per diffraction image an M^{1/6} scaling is seen. Using synthetic diffraction data for a small glutathione molecule as a challenging test case, successful determination of electron density was demonstrated for 20000 diffraction patterns with random orientations and an average of 82 elastically scattered and recorded photons per image, also in the presence of up to 50% background noise. The second scenario is exemplified and assessed for three biomolecules of different sizes. In all cases, determining the probability of a structure given set of diffraction patterns allowed successful discrimination between different conformations of the test molecules. A structure model of the glutathione tripeptide was refined in a Monte Carlo simulation from a random starting conformation. Further, effective distinguishing between three differently arranged immunoglobulin domains of a titin molecule and also different states of a ribosome in a tRNA translocation process was demonstrated. These results show that the proposed method is robust and enables structure determination from sparse and noisy x-ray diffraction images of single molecules spanning a wide range of molecular masses. PMID:25215765

Walczak, Micha?; Grubmüller, Helmut

2014-08-01

271

Diagnostics of plasma based on K, L and M x-ray line positions  

NASA Astrophysics Data System (ADS)

Ionization can affect the energy of characteristic x-ray lines sufficiently for a single line to be of value in plasma diagnostics. Recently, the ionization of a hot, dense tungsten plasma was determined from a detailed analysis of a single, highly resolved L x-ray line, and in an iridium plasma the change in energy of a single K x-ray line confirmed the theoretical estimate of the ionization. Diagnosing plasmas by these ionization energy shifts depends essentially on computations that can now be performed with sufficient accuracy, e.g. with the multi-configuration Dirac-Fock method. Besides extending earlier computations on the influence of outer-shell ionization on the energy of tungsten's K and L x-ray lines, this paper also presents the effect of ionization on the lower-energy M x-ray lines and a discussion of their relative merits for plasma diagnostics.

S?abkowska, Katarzyna; Szyma?ska, Ewa; Starosta, Joanna; Polasik, Marek; Pereira, Nino R.; Rzadkiewicz, Jacek; Kubkowska, Monika; Czarnecka, Agata

2014-05-01

272

Spectroscopic and X-ray Diffraction Study of Structural Disorder in Cryomilled and Amorphous Griseofulvin  

SciTech Connect

Structural disorder induced by cryogenic milling and by heating to the amorphous phase in the active pharmaceutical ingredient Griseofulvin has been studied using Raman spectroscopy, X-ray powder diffraction (XRPD), and fluorescence spectroscopy. A broad, exciting-frequency-independent scattering background in the Raman spectra and changes in intensities and splitting of some of the Raman lines due to lattice and molecular modes have been observed. In the cryomilled samples this strong background is deconvoluted into two components: one due to lattice disorder induced by cryomilling and the other due to Mie scattering from nanosized crystallites. A single-component background scattering attributed to lattice disorder is seen in the Raman spectrum of the amorphous sample. Fluorescence measurements showed an intrinsic fluorescence signal in as-received Griseofulvin that does not correspond to the inelastic background in the Raman spectra and, moreover, decreases in intensity upon cryomilling, thus excluding an assignment of the Raman background intensity to impurity- or molecular-defect-induced fluorescence. Wide-angle XRPD measurements on cryomilled Griseofulvin shows a broad two-component background consistent with the background-scattering component in the Raman data associated with lattice disorder, but at longer correlation lengths. Persistence of this disorder to even longer lengths is evident in small-angle synchrotron XRPD data on micronized Griseofulvin taken as a function of temperature from the crystalline to the amorphous phase.

A Zarow; B Zhou; X Wang; R Pinal; Z Iqbal

2011-12-31

273

Crystallization of medium length 1-alcohols in mesoporous silicon: An X-ray diffraction study  

E-print Network

The linear 1-alcohols n-C16H33OH, n-C17H35OH, n-C19H37OH have been imbibed and solidified in lined up, tubular mesopores of silicon with 10 nm and 15 nm mean diameters, respectively. X-ray diffraction measurements reveal a set of six discrete orientation states (''domains'') characterized by a perpendicular alignment of the molecules with respect to the long axis of the pores and by a four-fold symmetry about this direction, which coincides with the crystalline symmetry of the Si host. A Bragg peak series characteristic of the formation of bilayers indicates a lamellar structure of the spatially confined alcohol crystals in 15 nm pores. By contrast, no layering reflections could be detected for 10 nm pores. The growth mechanism responsible for the peculiar orientation states is attributed to a nano-scale version of the Bridgman technique of single-crystal growth, where the dominant growth direction is aligned parallelly to the long pore axes. Our observations are analogous to the growth phenomenology encounte...

Henschel, Anke; Knorr, Klaus

2008-01-01

274

Crystallization of medium length 1-alcohols in mesoporous silicon: An X-ray diffraction study  

E-print Network

The linear 1-alcohols n-C16H33OH, n-C17H35OH, n-C19H37OH have been imbibed and solidified in lined up, tubular mesopores of silicon with 10 nm and 15 nm mean diameters, respectively. X-ray diffraction measurements reveal a set of six discrete orientation states (''domains'') characterized by a perpendicular alignment of the molecules with respect to the long axis of the pores and by a four-fold symmetry about this direction, which coincides with the crystalline symmetry of the Si host. A Bragg peak series characteristic of the formation of bilayers indicates a lamellar structure of the spatially confined alcohol crystals in 15 nm pores. By contrast, no layering reflections could be detected for 10 nm pores. The growth mechanism responsible for the peculiar orientation states is attributed to a nano-scale version of the Bridgman technique of single-crystal growth, where the dominant growth direction is aligned parallelly to the long pore axes. Our observations are analogous to the growth phenomenology encountered for medium length n-alkanes confined in mesoporous silicon (Phys. Rev. E 75, 021607 (2007)) and may further elucidate why porous silicon matrices act as an effective nucleation-inducing material for protein solution crystallization.

Anke Henschel; Patrick Huber; Klaus Knorr

2008-03-27

275

TOPICAL REVIEW Quantitative strain analysis of surfaces and interfaces using extremely asymmetric x-ray diffraction  

NASA Astrophysics Data System (ADS)

Strain can reduce carrier mobility and the reliability of electronic devices and affect the growth mode of thin films and the stability of nanometer-scale crystals. To control lattice strain, a technique for measuring the minute lattice strain at surfaces and interfaces is needed. Recently, an extremely asymmetric x-ray diffraction method has been developed for this purpose. By employing Darwin's dynamical x-ray diffraction theory, quantitative evaluation of strain at surfaces and interfaces becomes possible. In this paper, we review our quantitative strain analysis studies on native SiO2/Si interfaces, reconstructed Si surfaces, Ni/Si(111)-H interfaces, sputtered III-V compound semiconductor surfaces, high-k/Si interfaces, and Au ion-implanted Si.

Akimoto, Koichi; Emoto, Takashi

2010-12-01

276

Calcinosis Circumscripta. A Case Report with X-ray Diffraction Studies  

PubMed Central

A small subcutaneous mass located on the right foreleg of a 3 months old Brittany spaniel was observed to progressively enlarge over a 2 month period. The lesion which had not affected locomotion was removed at 5 months of age and was diagnosed as calcinosis circumscripta. The chalk-like material contained in the lesion was studied by x-ray diffraction and from the crystallographic view point, the structure of this growth was not different from that of normal or abnormal calcification. As there is no agreement on the exact chemical arrangement of bone salts (13), the observed x-ray powder diffraction pattern may be taken as that corresponding to a calcium phosphate hydrated (14), a calcium phosphate of apatite structure (15), a pseudo-apatite (16), or a hydroxy apatite (17). ImagesFigure 1.Figure 2.Figure 3.Figure 4. PMID:17649393

Grice, H. C.; Hutchison, J. A.; Cloutier, J. A. R.

1962-01-01

277

Realizing in-plane surface diffraction by x-ray multiple-beam diffraction with large incidence angle  

NASA Astrophysics Data System (ADS)

Based on rigorous dynamical-theory calculations, we demonstrate the principle of an x-ray multiple-beam diffraction (MBD) scheme that overcomes the long-lasting difficulties of high-resolution in-plane diffraction from crystal surfaces. This scheme only utilizes symmetric reflection geometry with large incident angles but activates the out-of-plane and in-plane diffraction processes simultaneously and separately in the continuous MBD planes. The in-plane diffraction is realized by detoured MBD, where the intermediate diffracted waves propagate parallel to the surface, which corresponds to an absolute Bragg surface diffraction configuration that is extremely sensitive to surface structures. A series of MBD diffraction and imaging techniques may be developed from this principle to study surface/interface (misfit) strains, lateral nanostructures, and phase transitions of a wide range of (pseudo)cubic crystal structures, including ultrathin epitaxial films and multilayers, quantum dots, strain-engineered semiconductor or (multi)ferroic materials, etc.

Huang, Xian-Rong; Peng, Ru-Wen; Gog, Thomas; Siddons, D. P.; Assoufid, Lahsen

2014-11-01

278

X-ray diffraction study of elemental erbium to 70 GPa  

NASA Astrophysics Data System (ADS)

We have investigated phase transitions in elemental erbium in a diamond anvil cell (DAC) up to 70GPa using angular-dispersive x-ray powder diffraction methods. We present evidence of a series of phase transitions that appear to follow the anticipated hcp?Sm-type?doublehcp(dhcp)?distorted fcc sequence. In particular, we present evidence for the predicted dhcp?distorted fcc transition above 63GPa . Equation of state data are also presented up to 70GPa .

Pravica, Michael G.; Romano, Edward; Quine, Zachary

2005-12-01

279

Electrochemistry and in-situ X-ray diffraction of InSb in lithium batteries  

Microsoft Academic Search

The electrochemical reactions of lithium with the intermetallic compound, InSb, were studied in lithium coin cells using laminate electrodes fabricated from either single-crystal InSb wafers or ball-milled samples. In-situ X-ray diffraction data show that the InSb zinc-blende framework is unstable to extensive reaction with lithium; In is extruded from a fixed Sb lattice during `discharge' and is partially incorporated back

C. S. Johnson; J. T. Vaughey; M. M. Thackeray; T. Sarakonsri; S. A. Hackney; L. Fransson; K. Edström; J. O. Thomas

2000-01-01

280

Characterisation of Constructed Wetland Substrates by Chemical Sequential Extraction and X-Ray Diffraction Analyses  

Microsoft Academic Search

Substrates from four-and-a-half year old constructed wetlands built to treat wastewater from an active metal mine were analysed for elevated metal and sulphur concentrations by chemical sequential extractions and X-ray diffraction analyses. Amounts of Fe, Pb, Zn and S were quantified in substrates from the first cells of multi-celled (in-series) treatment wetland systems at three different depths. The analyses showed

Aisling D. O'Sullivan; Ronald Conlon; Bredagh Moran; Marinus Otte

2005-01-01

281

Time Resolved X-Ray Diffraction Measurements Of Phase Transitions In Lipid-Water Systems  

NASA Astrophysics Data System (ADS)

Time-resolved X-ray diffraction has been used to investigate phase transitions in lipid-water systems. A variety of lamellar and non-lamellar phases have been examined and the transit time of the transitions between phases determined. A comparison is made between the characteristic phase transition transit times for phospholipids, galactolipids and surfactants. Transitions have been measured which span times of less than one second to orders of minutes and longer.

Lis, L. J.; Quinn, P. J.

1986-08-01

282

Visualizing Chemical Reactions in Solution by Picosecond X-Ray Diffraction  

Microsoft Academic Search

We present a time-resolved x-ray diffraction study to monitor the recombination of laser-dissociated iodine molecules dissolved in CCl4. The change in structure of iodine is followed during the whole recombination process. The deexcitation of solute molecules produces a heating of the solvent and induces tiny changes in its structure. The variations in the distance between pairs of chlorine atoms in

Anton Plech; Michael Wulff; Savo Bratos; Fabien Mirloup; Rodolphe Vuilleumier; Friedrich Schotte; Philip A. Anfinrud

2004-01-01

283

Analysis of interfacial micromechanics of model composites using synchrotron microfocus X-ray diffraction  

Microsoft Academic Search

The deformation micromechanics of single-fibre embedded model composites of poly(p-phenylene benzobisoxazole) (PBO) and poly(p-phenylene terephthalamide) (PPTA) fibres, embedded in an epoxy resin have been examined using synchrotron microfocus X-ray\\u000a diffraction. Single fibres (in air) were deformed and the c-spacing monitored to establish a calibration of crystal strain against applied stress. Subsequently, the variation in crystal\\u000a strain along fibres, embedded in

Y. T. Shyng; J. A. Bennett; R. J. Young; R. J. Davies; S. J. Eichhorn

2006-01-01

284

Use of X-ray diffraction in a study of ammonia leaching of multimetal sulfides  

Microsoft Academic Search

X-ray diffraction has been used to study the changes in mineralogy that occur during ammonia leaching of sulfide minerals\\u000a and complex bulk sulfide concentrates. Leaching results in high extraction rates (>90 pct) of copper from chalcopyrite, zinc\\u000a from sphalerite, and lead from galena. However, under experimental leaching conditions (temperature, 115 C to 135 C; par-tial\\u000a pressure of oxygen, 1.5 kg\\/cm2;

K. Sarveswara Rao; R. P. Das; P. G. Mukunda; H. S. Ray

1993-01-01

285

Use of X-ray diffraction in a study of ammonia leaching of multimetal sulfides  

Microsoft Academic Search

X-ray diffraction has been used to study the changes in mineralogy that occur during ammonia leaching of sulfide minerals and complex bulk sulfide concentrates. Leaching results in high extraction rates (>90 pct) of copper from chalcopyrite, zinc from sphalerite, and lead from galena. However, under experimental leaching conditions (temperature, 115 °C to 135 °C; par-tial pressure of oxygen, 1.5 kg\\/cm2;

K. Sarveswara Rao; R. P. Das; P. G. Mukunda; H. S. Ray

1993-01-01

286

X-ray diffraction determination of residual stresses in functionally graded WC–Co composites  

Microsoft Academic Search

X-ray diffraction was used to determine the thermal residual stresses that develop in a functionally graded WC–Co composite. Stresses were measured in both WC and Co phases at various depths. Pole figures were obtained in order to determine optimal sample orientations that provided adequate intensity for measurements in the Co phase. For WC, the in-plane compressive residual stresses varied approximately

C. Larsson; M. Odén

2004-01-01

287

Evolution of Surface Morphology During Pulsed Laser Deposition from Time Resolved X-ray Surface Diffraction  

Microsoft Academic Search

We have used in situ time-resolved surface x-ray diffraction measurements during pulsed laser deposition (PLD) of SrTiO3 to study the kinetics and morphology of surface aggregation during film growth. The arrival of atoms within 2 mu s during PLD separates the crystallization from the evolution phase. Previous surface truncation rod (STR) measurements have shown that crystallization into SrTiO3 islands occurs

J. Z. Tischler; B. C. Larson; Gyula Eres; C. M. Rouleau; P. Zschack

2002-01-01

288

Rietveld Refinement on X-Ray Diffraction Patterns of Bioapatite in Human Fetal Bones  

PubMed Central

Bioapatite, the main constituent of mineralized tissue in mammalian bones, is a calcium-phosphate-based mineral that is similar in structure and composition to hydroxyapatite. In this work, the crystallographic structure of bioapatite in human fetuses was investigated by synchrotron radiation x-ray diffraction (XRD) and microdiffraction (?-XRD) techniques. Rietveld refinement analyses of XRD and ?-XRD data allow for quantitative probing of the structural modifications of bioapatite as functions of the mineralization process and gestational age. PMID:12609904

Meneghini, Carlo; Dalconi, Maria Chiara; Nuzzo, Stefania; Mobilio, Settimio; Wenk, Rudy H.

2003-01-01

289

Lattice Misfit Measurement in Inconel 625 by X-Ray Diffraction Technique  

Microsoft Academic Search

Determination of lattice misfit and microstructural parameters of the coherent precipitates in Ni based alloy Inconel-625 is a challenging problem as their peaks are completely overlapping among themselves and also with the matrix. We have used a novel X-ray diffraction technique on the bulk samples of Inconel 625 at different heat-treated conditions to determine the lattice parameters, the lattice misfit

P. Mukherjee; A. Sarkar; P. Barat; T. Jayakumar; S. Mahadevan; Sanjay K. Rai

2006-01-01

290

X-ray diffraction studies of phase transformations in heavy-metal fluoride glasses  

NASA Technical Reports Server (NTRS)

Powder X-ray diffraction and differential scanning calorimetry studies of the crystallization properties of five ZrF4-based glass compositions have indicated that the crystalline phase in Zr-Ba-La-Pb fluoride glass is beta-BaZrF6; no such identification of crystal phases was obtainable, however, for the other glasses. Reversible polymorphic phase transformations occur in Zr-Ba-La-Li and Zr-Ba-La-Na fluoride glasses, upon heating to higher temperatures.

Bansal, N. P.; Doremus, R. H.

1985-01-01

291

Recombination of photodissociated iodine: A time-resolved x-ray-diffraction study  

SciTech Connect

A time-resolved x-ray-diffraction experiment is presented that aims to study the recombination of laser-dissociated iodine molecules dissolved in CCl{sub 4}. This process is monitored over an extended time interval from pico- to microseconds. The variations of atom-atom distances are probed with a milliangstrom resolution. A recent theory of time-resolved x-ray diffraction is used to analyze the experimental data; it employs the correlation function approach of statistical mechanics. The most striking outcome of this study is the experimental determination of time-dependent I-I atom-atom distribution functions. The structure of the CCl{sub 4} solvent changes simultaneously; the solvent thus appears as a reaction partner rather than an inert medium hosting it. Thermal expansion of the system is nonuniform in time, an effect due to the presence of the acoustic horizon. One concludes that a time-resolved x-ray diffraction permits real-time visualization of solvent and solute motions during a chemical reaction.

Wulff, M.; Bratos, S.; Plech, A.; Vuilleumier, R.; Mirloup, F.; Lorenc, M.; Kong, Q.; Ihee, H. [European Synchrotron Radiation Facility, Grenoble Cedex 38043, BP 220 (France); Laboratoire de Physique, Theorique des Liquides, Universite Pierre et Marie Curie, Case Courrier 121, 4 Place Jussieu, Paris Cedex 75252 (France); Fachbereich Physik der Universitaet Konstanz, Universitaetsstrasse 10, D-78457 Constance (Germany); Laboratoire de Physique, Theorique des Liquides, Universite Pierre et Marie Curie, Case Courrier 121, 4 Place Jussieu, Paris Cedex 75252 (France); European Synchrotron Radiation Facility, Grenoble Cedex 38043, BP 220 (France); Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of) and School of Molecular Science (BK21), Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea)

2006-01-21

292

X-Ray Diffraction Analysis of NLO Crystals: Traditional Applications and More New Opportunities  

NASA Technical Reports Server (NTRS)

Single crystal X-ray diffraction analysis is one of the more important methods for the molecular and crystal structure determination of matter and therefore it has a great importance in material science including design and engineering of different compounds with non-linear optical (NLO) properties. It was shown in our previous publications that this method provides unique information about molecular structure of NLO compounds, their crystal symmetry and crystal packing arrays, molecular conformation and geometries and many other structural and electronic characteristics that are important for understanding the nature of NLO properties of solids. A very new application of the X-ray diffraction method is related to analysis of the electron density distribution p(r) in crystals and some of its characteristics (atomic and group charges, dipole and higher multipole moments, etc.), that may be obtained directly form the diffraction measurements. In the present work, we will discuss our preliminary low temperature high-resolution X-ray data for the m-nitroaniline (mNA) single crystal (VI). This is one of the "classical" organic NLO materials and electron density distribution analysis in this simple compound has a great scientific interest.

Antipin, Mikhail Yu.; Clark, Ronald D.; Nesterov, Vladimir N.

1998-01-01

293

Experimental developments to obtain real-time x-ray diffraction measurements in plate impact experiments  

SciTech Connect

An experimental facility was developed to obtain real-time, quantitative, x-ray diffraction data in laboratory plate impact experiments. A powder gun, to generate plane wave loading in samples, was designed and built specifically to permit flash x-ray diffraction measurements in shock-compression experiments. Spatial resolution and quality of the diffracted signals were improved significantly over past attempts through partial collimation of the incident beam and the use of two-dimensional detectors to record data from shocked crystals. The experimental configuration and synchronization issues are discussed, and relevant details of the x-ray system and the powder gun are described. Representative results are presented from experiments designed to determine unit cell compression in shock-compressed LiF single crystals subjected to both elastic and elastic-plastic deformation, respectively. The developments described here are expected to be useful for examining lattice deformation and structural changes in shock wave compression studies. {copyright} {ital 1999 American Institute of Physics.}

Gupta, Y.M.; Zimmerman, K.A.; Rigg, P.A.; Zaretsky, E.B.; Savage, D.M.; Bellamy, P.M. [Institute for Shock Physics and Department of Physics, Washington State University, Pullman, Washington 99164-2816 (United States)] [Institute for Shock Physics and Department of Physics, Washington State University, Pullman, Washington 99164-2816 (United States)

1999-10-01

294

Residual stress characterization of welds and post-weld processes using x-ray diffraction techniques  

NASA Astrophysics Data System (ADS)

This paper illustrates the importance of residual stress characterization in welds and post weld processes. The failure to characterize residual stresses created during welding and/or post weld processes can lead to unexpected occurrences of stress corrosion cracking, distortion, fatigue cracking as well as instances of over design or over processing. The development of automated residual stress mapping and the availability of portable and fast equipment have now made the characterization of residual stresses using x-ray diffraction practical for process control and optimization. The paper presents examples where x-ray diffraction residual stress characterization techniques were applied on various kinds of welds including arc welds, TIG welds, resistance welds, laser welds and electron beam welds. The nondestructive nature of the x-ray diffraction technique has made the residual stress characterization of welds a useful tool for process optimization and failure analysis, particularly since components can be measured before and after welding and post welding processes. Some examples presented show the residual stresses before and after the application of post weld processes such as shot peening, grinding and heat treatment.

Brauss, Michael E.; Pineault, James A.; Eckersley, John S.

1998-03-01

295

Femtosecond Diffractive Imaging with a Soft-X-Ray Free-Electron Laser  

SciTech Connect

Theory predicts that with an ultrashort and extremely bright coherent X-ray pulse, a single diffraction pattern may be recorded from a large macromolecule, a virus, or a cell before the sample explodes and turns into a plasma. Here we report the first experimental demonstration of this principle using the FLASH soft X-ray free-electron laser. An intense 25 fs, 4 x 10{sup 13} W/cm{sup 2} pulse, containing 10{sup 12} photons at 32 nm wavelength, produced a coherent diffraction pattern from a nano-structured non-periodic object, before destroying it at 60,000 K. A novel X-ray camera assured single photon detection sensitivity by filtering out parasitic scattering and plasma radiation. The reconstructed image, obtained directly from the coherent pattern by phase retrieval through oversampling, shows no measurable damage, and extends to diffraction-limited resolution. A three-dimensional data set may be assembled from such images when copies of a reproducible sample are exposed to the beam one by one.

Chapman, H.N.; Barty, A.; Bogan, M.J.; Boutet, S.; Frank, M.; Hau-Riege, S.P.; Marchesini, S.; Woods, B.W.; Bajt, S.; Benner, H.; London, R.A.; Plonjes, E.; Kuhlmann, M.; Treusch, R.; Dusterer, S.; Tschentscher, T.; Schneider, J.R.; Spiller, E.; Moller, T.; Bostedt, C.; Hoener, M.; /LLNL, Livermore /UC, Davis /SLAC, SSRL /Uppsala U. /DESY /Berlin, Tech. U.; ,

2010-10-07

296

Analysis of diatomite sediments from a paleolake in central Mexico using PIXE, X-ray tomography and X-ray diffraction  

NASA Astrophysics Data System (ADS)

Diatomite samples from paleolake Tlaxcala, in Central Mexico, have been analyzed using proton induced X-ray emission (PIXE), X-ray tomography and X-ray diffraction. Chiseled blocks were scanned with a 0.7 MeV proton beam, 0.1 mm in diameter, in 0.25 mm steps across the sediments. X-ray tomography with the same step sizes was then applied, in order to compare the concentrations obtained with PIXE and the material density in the sediment layers. Three different kinds of layers were found, related to their colors: dark, white and gray. The composition of the layers is fairly uniform. The dark zone is enriched in Al, K, Ca, Ti, Mn, and Fe. This dark layer may be associated with eruptions of the Malitzin volcano. The white zone is found to contain diatomite of a high purity, with traces of K, Ca, and Fe, while the gray zones are also Al enriched, suggesting a clay contamination of the diatomite. X-ray diffraction of materials obtained from each main layer showed that the white and gray phases are highly amorphous, with a small component of cristobalite, as expected from the diatom sediment diagenesis, while the dark layer contains also important amounts of anorthite and orthoclase, supporting the volcanic origin of this layer.

Miranda, J.; Oliver, A.; Vilaclara, G.; Rico-Montiel, R.; Macías, V. M.; Ruvalcaba, J. L.; Zenteno, M. A.

1994-03-01

297

X-ray and neutron diffraction measurements of dislocation density and subgrain size in a friction stir welded aluminum alloy  

SciTech Connect

The dislocation density and subgrain size were determined in the base material and friction-stir welds of 6061-T6 aluminum alloy. High-resolution X-ray diffraction measurement was performed in the base material. The result of the line profile analysis of the X-ray diffraction peak shows that the dislocation density is about 4.5 x 10{sup 14} m{sup 02} and the subgrain size is about 200 nm. Meanwhile, neutron diffraction measurements have been performed to observe the diffraction peaks during friction-stir welding (FSW). The deep penetration capability of the neutron enables us to measure the peaks from the midplane of the Al plate underneath the tool shoulder of the friction-stir welds. The peak broadening analysis result using the Williamson-Hall method shows the dislocation density of about 3.2 x 10{sup 15} m{sup -2} and subgrain size of about 160 nm. The significant increase of the dislocation density is likely due to the severe plastic deformation during FSW. This study provides an insight into understanding the transient behavior of the microstructure under severe thermomechanical deformation.

Claussen, Bjorn [Los Alamos National Laboratory; Woo, Wanchuck [ORNL; Zhili, Feng [ORNL; Edward, Kenik [ORNL; Ungar, Tamas [EOTVOS UNIV.

2009-01-01

298

X-ray absorption microtomography (microCT) and small beam diffraction mapping of sea urchin teeth  

Microsoft Academic Search

Two noninvasive X-ray techniques, laboratory X-ray absorption microtomography (microCT) and X-ray diffraction mapping, were used to study teeth of the sea urchin Lytechinus variegatus. MicroCT revealed low attenuation regions at near the tooth’s stone part and along the carinar process—central prism boundary; this latter observation appears to be novel. The expected variation of Mg fraction x in the mineral phase

S. R. Stock; J. Barss; T. Dahl; A. Veis; J. D. Almer

2002-01-01

299

Hybrid quantitative simulation on the in-line phase-contrast x-ray imaging of three dimensional samples under actual clinic imaging parameters  

SciTech Connect

A hybrid model combining Monte Carlo method with diffraction theory of wave optics has been developed and applied to quantitatively simulate the in-line diffractive phase-contrast x-ray imaging of three dimensional tissue samples under actual clinic imaging parameters. The primary microcosmic interactions of medical-energy x-ray within matter including photoabsorption, Compton scattering, and coherent scattering, have been taken into account in the Monte Carlo simulation. A diffraction processing based on Fresnel diffraction theory is carried out to simulate the macroscopic diffraction effect. A comparison with experiment results has also been performed.

Yu Hong; Han Shensheng [Key Laboratory for Quantum Optics of CAS, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800 (China); Ding Jianhui; Jiang Zhaoxia; Peng Weijun [Department of Radiology, Fudan University, Shanghai Cancer Center, Shanghai 200032 (China)

2009-07-06

300

Hybrid quantitative simulation on the in-line phase-contrast x-ray imaging of three dimensional samples under actual clinic imaging parameters  

NASA Astrophysics Data System (ADS)

A hybrid model combining Monte Carlo method with diffraction theory of wave optics has been developed and applied to quantitatively simulate the in-line diffractive phase-contrast x-ray imaging of three dimensional tissue samples under actual clinic imaging parameters. The primary microcosmic interactions of medical-energy x-ray within matter including photoabsorption, Compton scattering, and coherent scattering, have been taken into account in the Monte Carlo simulation. A diffraction processing based on Fresnel diffraction theory is carried out to simulate the macroscopic diffraction effect. A comparison with experiment results has also been performed.

Yu, Hong; Han, Shensheng; Ding, Jianhui; Jiang, Zhaoxia; Peng, Weijun

2009-07-01

301

Time-resolved coherent X-ray diffraction imaging of surface acoustic waves  

PubMed Central

Time-resolved coherent X-ray diffraction experiments of standing surface acoustic waves, illuminated under grazing incidence by a nanofocused synchrotron beam, are reported. The data have been recorded in stroboscopic mode at controlled and varied phase between the acoustic frequency generator and the synchrotron bunch train. At each time delay (phase angle), the coherent far-field diffraction pattern in the small-angle regime is inverted by an iterative algorithm to yield the local instantaneous surface height profile along the optical axis. The results show that periodic nanoscale dynamics can be imaged at high temporal resolution in the range of 50?ps (pulse length). PMID:25294979

Nicolas, Jan-David; Reusch, Tobias; Osterhoff, Markus; Sprung, Michael; Schulein, Florian J. R.; Krenner, Hubert J.; Wixforth, Achim; Salditt, Tim

2014-01-01

302

High resolution X-ray diffraction imaging of lead tin telluride  

NASA Technical Reports Server (NTRS)

High resolution X-ray diffraction images of two directly comparable crystals of lead tin telluride, one Bridgman-grown on Space Shuttle STS 61A and the other terrestrially Bridgman-grown under similar conditions from identical material, present different subgrain structure. In the terrestrial, sample 1 the appearance of an elaborate array of subgrains is closely associated with the intrusion of regions that are out of diffraction in all of the various images. The formation of this elaborate subgrain structure is inhibited by growth in microgravity.

Steiner, Bruce; Dobbyn, Ronald C.; Black, David; Burdette, Harold; Kuriyama, Masao; Spal, Richard; Simchick, Richard; Fripp, Archibald

1991-01-01

303

On the microstructure of nanoporous gold: an x-ray diffraction study  

SciTech Connect

The evolution of the grain structure, internal stresses, and the lattice misorientations of nanoporous gold (npAu) during dealloying of bulk (3D) Ag-Au alloy samples was studied by various in-situ and ex-situ X-ray diffraction techniques including powder and Laue diffraction. The experiments reveal that the dealloying process preserves the original crystallographic structure, but leads to a small spread in orientations within individual grains. Furthermore, most grains develop in-plane tensile stress. The feature size of the developing nanoporous structure increases with increasing dealloying time.

Van Petegem, S; Brandstetter, S; Maa?, R; Schmitt, B; Borca, C; Van Swygenhoven, H; Hodge, A M; El-Dasher, B S; Biener, J

2008-08-26

304

Diffractive imaging at large Fresnel number: Challenge of dynamic mesoscale imaging with hard x rays  

NASA Astrophysics Data System (ADS)

Real materials have structure at both the atomic or crystalline scale as well as at interfaces and defects at the larger scale of grains. There is a need for the study of materials at the "mesoscale," the scale at which subgranular physical processes and intergranular organization couple to determine microstructure, crucially impacting constitutive response at the engineering macroscale. Diffractive imaging using photons that can penetrate multiple grains of material would be a transformative technique for the study of the performance of materials in dynamic extremes. Thicker samples imply higher energy photons of shorter wavelength, and imaging of multiple grains implies bigger spot sizes. Such imaging requires the use of future planned and proposed hard x-ray free electron lasers (such as the European XFEL) to provide both the spatial coherence transverse to the large spots and the peak brilliance to provide the short illumination times. The result is that the Fresnel number of the system becomes large and is no longer in the Fraunhofer far-field limit. The interrelated issues of diffractive imaging at large Fresnel number are analyzed, including proof that diffractive imaging is possible in this limit and estimates of the signal-to-noise possible. In addition, derivation of the heating rates for brilliant pulses of x rays are presented. The potential and limitations on multiple dynamic images are derived. This paper will present a study of x-ray interactions with materials in this new regime of spatially coherent but relatively large mesoscale spots at very hard energies. It should provide the theory and design background for the experiments and facilities required to control materials in extreme environments, in particular for the next generation of very-hard-x-ray free electron lasers.

Barber, John L.; Barnes, Cris W.; Sandberg, Richard L.; Sheffield, Richard L.

2014-05-01

305

Real-time, high-resolution x-ray diffraction measurements on shocked crystals at a synchrotron facility  

SciTech Connect

The Advanced Photon Source (APS) at Argonne National Laboratory was used to obtain real-time, high-resolution x-ray diffraction measurements to determine the microscopic response of shock-compressed single crystals. Disk shaped samples were subjected to plane shock wave compression by impacting them with half-inch diameter, flat-faced projectiles. The projectiles were accelerated to velocities ranging between 300 and 1200 m/s using a compact powder gun designed specifically for use at a synchrotron facility. The experiments were designed to keep the sample probed volume under uniaxial strain and constant stress for a duration longer than the 153.4 ns spacing between x-ray bunches. X-rays from a single pulse (<100 ps duration) out of the periodic x-ray pulses emitted by the synchrotron were used for the diffraction measurements. A synchronization and x-ray detection technique was developed to ensure that the measured signal was obtained unambiguously from the desired x-ray pulse incident on the sample while the sample was in a constant uniaxial strain state. The synchronization and x-ray detection techniques described can be used for a variety of x-ray measurements on shock compressed solids and liquids at the APS. Detailed procedures for applying the Bragg-Brentano parafocusing approach to single crystals at the APS are presented. Analytic developments to determine the effects of crystal substructure and non-ideal geometry on the diffraction pattern position and shape are presented. Representative real-time x-ray diffraction data, indicating shock-induced microstructural changes, are presented for a shock-compressed Al(111) sample. The experimental developments presented here provided, in part, the impetus for the Dynamic Compression Sector (DCS) currently under development at the APS. Both the synchronization/x-ray detection methods and the analysis equations for high-resolution single crystal x-ray diffraction can be used at the DCS.

Gupta, Y. M.; Turneaure, Stefan J.; Perkins, K.; Zimmerman, K.; Arganbright, N. [Institute for Shock Physics and the Department of Physics, Washington State University, Pullman, Washington 99164-2816 (United States); Shen, G.; Chow, P. [HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60437 (United States)

2012-12-15

306

Comparison of Extended X-ray Absorption Fine Structure and Scherrer Analysis of X-ray Diffraction as Methods for Determining Mean Sizes of Polydisperse Nanoparticles  

SciTech Connect

Curve fitting of extended x-ray absorption fine structure (EXAFS) spectra, transmission electron microscopy (TEM) imaging, and Scherrer analysis of x-ray diffraction (XRD) are compared as methods for determining the mean crystallite size in polydisperse samples of platinum nanoparticles. By applying the techniques to mixtures of pure samples, it is found that EXAFS correctly determines the relative mean sizes of these polydisperse samples, while XRD tends to be weighted more toward the largest crystallites in the sample. Results for TEM are not clear cut, due to polycrystallinity and aggregation, but are consistent with the other results.

Calvin,S.; Luo, S.; Caragianis-Broadbridge, C.; McGuinness, J.; Anderson, E.; Lehman, A.; Wee, K.; Morrison, S.; Kurihara, L.

2005-01-01

307

Solar X-Ray Spectroscopy and Optical Line Polarimetry.  

National Technical Information Service (NTIS)

An experiment was performed to measure the X-ray spectrum of the solar corona between 1.8 and 5.4A. Panels of mosaic graphite crystals were used as dispersive elements and proportional counters as detectors. The spectrometer was carried aloft by an Aerobe...

J. R. P. Angel, M. C. Weisskopf, R. Novick, R. S. Wolff

1973-01-01

308

DynAMITe: a prototype large area CMOS APS for breast cancer diagnosis using x-ray diffraction measurements  

NASA Astrophysics Data System (ADS)

X-ray diffraction studies are used to identify specific materials. Several laboratory-based x-ray diffraction studies were made for breast cancer diagnosis. Ideally a large area, low noise, linear and wide dynamic range digital x-ray detector is required to perform x-ray diffraction measurements. Recently, digital detectors based on Complementary Metal-Oxide- Semiconductor (CMOS) Active Pixel Sensor (APS) technology have been used in x-ray diffraction studies. Two APS detectors, namely Vanilla and Large Area Sensor (LAS), were developed by the Multidimensional Integrated Intelligent Imaging (MI-3) consortium to cover a range of scientific applications including x-ray diffraction. The MI-3 Plus consortium developed a novel large area APS, named as Dynamically Adjustable Medical Imaging Technology (DynAMITe), to combine the key characteristics of Vanilla and LAS with a number of extra features. The active area (12.8 × 13.1 cm2) of DynaMITe offers the ability of angle dispersive x-ray diffraction (ADXRD). The current study demonstrates the feasibility of using DynaMITe for breast cancer diagnosis by identifying six breast-equivalent plastics. Further work will be done to optimize the system in order to perform ADXRD for identification of suspicious areas of breast tissue following a conventional mammogram taken with the same sensor.

Konstantinidis, A.; Anaxagoras, T.; Esposito, M.; Allinson, N.; Speller, R.

2012-03-01

309

Quantitative X-RAy Diffraction Analysis of Four Types of Amphibolic Asbestos by the Silver Membrane Filter Method  

Microsoft Academic Search

In this paper, the method that utilizes the X-ray diffraction technique combined with a procedure for X-ray absorption correction, already applied to chrysotile, was extended to the quantitative determination of microgram quantities of four types of amphibolic asbestos. These are: crocidolite, amosite, tremolite and anthophyllite. The effectiveness of the absorption correction procedure, based on the use of a silver membrane

S. Puledda; A. Marconi

1989-01-01

310

Quantitative X-Ray Diffraction Analysis of Asbestos by the Silver Membrane Filter Method: Application to Chrysotile  

Microsoft Academic Search

A method is described for the quantitative analysis of microgram quantities of chrysotile. This method utilizes X-ray diffraction combined with an X-ray absorption correction procedure, based on the use of a silver membrane filter and includes a dispersion technique that eliminates the possibility of chrysotile fiber alterations. It also proposes an appropriate value for the deposition area of the sample

S. PULEDDA; A. MARCONI

1990-01-01

311

Microelemental and mineral compositions of pathogenic biomineral concrements: SRXFA, X-ray powder diffraction and vibrational spectroscopy data  

NASA Astrophysics Data System (ADS)

X-ray fluorescence analysis using synchrotron radiation (SRXRF), X-ray powder diffraction, infrared and Raman spectroscopy had been applied for determination of microelemental and mineral composition of the kidney stones, gallstones and salivalities from natives of Novosibirsk and Novosibirsk region, Russia. The relationship between mineral, organic and microelemental composition of pathogenic calcilus was shown.

Moroz, T. N.; Palchik, N. A.; Dar'in, A. V.

2009-05-01

312

Imaging live cell in micro-liquid enclosure by X-ray laser diffraction  

NASA Astrophysics Data System (ADS)

Emerging X-ray free-electron lasers with femtosecond pulse duration enable single-shot snapshot imaging almost free from sample damage by outrunning major radiation damage processes. In bioimaging, it is essential to keep the sample close to its natural state. Conventional high-resolution imaging, however, suffers from severe radiation damage that hinders live cell imaging. Here we present a method for capturing snapshots of live cells kept in a micro-liquid enclosure array by X-ray laser diffraction. We place living Microbacterium lacticum cells in an enclosure array and successively expose each enclosure to a single X-ray laser pulse from the SPring-8 Angstrom Compact Free-Electron Laser. The enclosure itself works as a guard slit and allows us to record a coherent diffraction pattern from a weakly-scattering submicrometre-sized cell with a clear fringe extending up to a 28-nm full-period resolution. The reconstructed image reveals living whole-cell structures without any staining, which helps advance understanding of intracellular phenomena.

Kimura, Takashi; Joti, Yasumasa; Shibuya, Akemi; Song, Changyong; Kim, Sangsoo; Tono, Kensuke; Yabashi, Makina; Tamakoshi, Masatada; Moriya, Toshiyuki; Oshima, Tairo; Ishikawa, Tetsuya; Bessho, Yoshitaka; Nishino, Yoshinori

2014-01-01

313

Imaging live cell in micro-liquid enclosure by X-ray laser diffraction.  

PubMed

Emerging X-ray free-electron lasers with femtosecond pulse duration enable single-shot snapshot imaging almost free from sample damage by outrunning major radiation damage processes. In bioimaging, it is essential to keep the sample close to its natural state. Conventional high-resolution imaging, however, suffers from severe radiation damage that hinders live cell imaging. Here we present a method for capturing snapshots of live cells kept in a micro-liquid enclosure array by X-ray laser diffraction. We place living Microbacterium lacticum cells in an enclosure array and successively expose each enclosure to a single X-ray laser pulse from the SPring-8 Angstrom Compact Free-Electron Laser. The enclosure itself works as a guard slit and allows us to record a coherent diffraction pattern from a weakly-scattering submicrometre-sized cell with a clear fringe extending up to a 28-nm full-period resolution. The reconstructed image reveals living whole-cell structures without any staining, which helps advance understanding of intracellular phenomena. PMID:24394916

Kimura, Takashi; Joti, Yasumasa; Shibuya, Akemi; Song, Changyong; Kim, Sangsoo; Tono, Kensuke; Yabashi, Makina; Tamakoshi, Masatada; Moriya, Toshiyuki; Oshima, Tairo; Ishikawa, Tetsuya; Bessho, Yoshitaka; Nishino, Yoshinori

2014-01-01

314

Imaging live cell in micro-liquid enclosure by X-ray laser diffraction  

PubMed Central

Emerging X-ray free-electron lasers with femtosecond pulse duration enable single-shot snapshot imaging almost free from sample damage by outrunning major radiation damage processes. In bioimaging, it is essential to keep the sample close to its natural state. Conventional high-resolution imaging, however, suffers from severe radiation damage that hinders live cell imaging. Here we present a method for capturing snapshots of live cells kept in a micro-liquid enclosure array by X-ray laser diffraction. We place living Microbacterium lacticum cells in an enclosure array and successively expose each enclosure to a single X-ray laser pulse from the SPring-8 Angstrom Compact Free-Electron Laser. The enclosure itself works as a guard slit and allows us to record a coherent diffraction pattern from a weakly-scattering submicrometre-sized cell with a clear fringe extending up to a 28-nm full-period resolution. The reconstructed image reveals living whole-cell structures without any staining, which helps advance understanding of intracellular phenomena. PMID:24394916

Kimura, Takashi; Joti, Yasumasa; Shibuya, Akemi; Song, Changyong; Kim, Sangsoo; Tono, Kensuke; Yabashi, Makina; Tamakoshi, Masatada; Moriya, Toshiyuki; Oshima, Tairo; Ishikawa, Tetsuya; Bessho, Yoshitaka; Nishino, Yoshinori

2014-01-01

315

X-ray diffraction in the pulsed laser heated diamond anvil cell  

SciTech Connect

We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell at pressure up to 60 GPa. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 {mu}s pulse width synchronized with a gated x-ray detector (Pilatus) and time-resolved radiometric temperature measurements. This enables the time domain measurements as a function of temperature in a microsecond time scale (averaged over many events, typically more than 10 000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration, samples 4 {mu}m thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformities as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. This delicate control, which may also prevent chemical reactivity and diffusion, enables accurate measurement of melting curves, phase changes, and thermal equations of state.

Goncharov, Alexander F.; Struzhkin, Viktor V.; Dalton, D. Allen [Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd., NW, Washington, DC 20015 (United States); Prakapenka, Vitali B.; Kantor, Innokenty; Rivers, Mark L. [Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637 (United States)

2010-11-15

316

X-ray diffraction in the pulsed laser heated diamond anvil cell  

SciTech Connect

We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell at pressure up to 60 GPa. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 {micro}s pulse width synchronized with a gated x-ray detector (Pilatus) and time-resolved radiometric temperature measurements. This enables the time domain measurements as a function of temperature in a microsecond time scale (averaged over many events, typically more than 10,000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration, samples 4 {micro}m thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformities as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. This delicate control, which may also prevent chemical reactivity and diffusion, enables accurate measurement of melting curves, phase changes, and thermal equations of state.

Goncharov, Alexander F.; Prakapenka, Vitali B.; Struzhkin, Viktor V.; Kantor, Innokenty; Rivers, Mark L.; Dalton, D. Allen (CIW); (UC)

2010-11-19

317

Room temperature femtosecond X-ray diffraction of photosystem II microcrystals  

PubMed Central

Most of the dioxygen on earth is generated by the oxidation of water by photosystem II (PS II) using light from the sun. This light-driven, four-photon reaction is catalyzed by the Mn4CaO5 cluster located at the lumenal side of PS II. Various X-ray studies have been carried out at cryogenic temperatures to understand the intermediate steps involved in the water oxidation mechanism. However, the necessity for collecting data at room temperature, especially for studying the transient steps during the O–O bond formation, requires the development of new methodologies. In this paper we report room temperature X-ray diffraction data of PS II microcrystals obtained using ultrashort (< 50 fs) 9 keV X-ray pulses from a hard X-ray free electron laser, namely the Linac Coherent Light Source. The results presented here demonstrate that the ”probe before destroy” approach using an X-ray free electron laser works even for the highly-sensitive Mn4CaO5 cluster in PS II at room temperature. We show that these data are comparable to those obtained in synchrotron radiation studies as seen by the similarities in the overall structure of the helices, the protein subunits and the location of the various cofactors. This work is, therefore, an important step toward future studies for resolving the structure of the Mn4CaO5 cluster without any damage at room temperature, and of the reaction intermediates of PS II during O–O bond formation. PMID:22665786

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

2012-01-01

318

Room temperature femtosecond X-ray diffraction of photosystem II microcrystals.  

PubMed

Most of the dioxygen on earth is generated by the oxidation of water by photosystem II (PS II) using light from the sun. This light-driven, four-photon reaction is catalyzed by the Mn(4)CaO(5) cluster located at the lumenal side of PS II. Various X-ray studies have been carried out at cryogenic temperatures to understand the intermediate steps involved in the water oxidation mechanism. However, the necessity for collecting data at room temperature, especially for studying the transient steps during the O-O bond formation, requires the development of new methodologies. In this paper we report room temperature X-ray diffraction data of PS II microcrystals obtained using ultrashort (< 50 fs) 9 keV X-ray pulses from a hard X-ray free electron laser, namely the Linac Coherent Light Source. The results presented here demonstrate that the "probe before destroy" approach using an X-ray free electron laser works even for the highly-sensitive Mn(4)CaO(5) cluster in PS II at room temperature. We show that these data are comparable to those obtained in synchrotron radiation studies as seen by the similarities in the overall structure of the helices, the protein subunits and the location of the various cofactors. This work is, therefore, an important step toward future studies for resolving the structure of the Mn(4)CaO(5) cluster without any damage at room temperature, and of the reaction intermediates of PS II during O-O bond formation. PMID:22665786

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

2012-06-19

319

Glancing Angle Dependence of the X-Ray Emission Measured under Total Reflection Angle X-Ray Spectroscopy (TRAXS) Condition during Reflection High Energy Electron Diffraction Observation  

NASA Astrophysics Data System (ADS)

We measured the glancing angle (?g) dependence of the X-ray emission from Si(111)-\\sqrt{3}×\\sqrt{3}-Ag and ?-\\sqrt{3}×\\sqrt{3}-Au surfaces during Reflection High Energy Electron Diffraction observation under the Total Reflection Angle X-ray Spectroscopy condition. The characteristic X-rays AgL and AuM decreased according to 1/sin ?g. The function 1/\\sin?g is easily understood in terms of Ag and Au atoms located at the top layer of the surface. The SiK and the bremsstrahlung showed broad peaks around 8°. These trends of the curves are explained by an analysis using Monte Carlo electron trajectory simulation. By measuring the glancing angle dependence we can easily distinguish whether or not a specific kind of atom is confined at the top layer of the surface.

Yamanaka, Toshiro; Hanada, Takashi; Ino, Shozo; Daimon, Hiroshi

1992-10-01

320

Imaging at the X-ray Frontier: Coherent Diffraction Imaging (CDI) for Nano and Bioscience  

NASA Astrophysics Data System (ADS)

For centuries, lens-based microscopy, such as light, phase-contrast, fluorescence, confocal and electron microscopy, has played an important role in the evolution of modern sciences and technologies. In 1999, a novel form of microscopy, i.e. coherent diffraction imaging (also termed coherent diffraction microscopy or lensless imaging) was developed and transformed our traditional view of microscopy, in which the diffraction pattern of a noncrystalline object or a nanocrystal is first measured and then directly phased to obtain a high resolution image. The well-known phase problem is solved by the oversampling method in combination with iterative algorithms whose principle can be traced back to the Shannon sampling theorem. In this talk, I will briefly discuss the principle of coherent diffraction imaging and illustrate its broad application in nano and bioscience by using synchrotron radiation, high harmonic generation and X-ray free electron lasers.

Miao, Jianwei

2013-03-01

321

Data preparation and evaluation techniques for x-ray diffraction microscopy  

PubMed Central

The post-experiment processing of X-ray Diffraction Microscopy data is often time-consuming and difficult. This is mostly due to the fact that even if a preliminary result has been reconstructed, there is no definitive answer as to whether or not a better result with more consistently retrieved phases can still be obtained. We show here that the first step in data analysis, the assembly of two-dimensional diffraction patterns from a large set of raw diffraction data, is crucial to obtaining reconstructions of highest possible consistency. We have developed software that automates this process and results in consistently accurate diffraction patterns. We have furthermore derived some criteria of validity for a tool commonly used to assess the consistency of reconstructions, the phase retrieval transfer function, and suggest a modified version that has improved utility for judging reconstruction quality. PMID:20940752

Steinbrener, Jan; Nelson, Johanna; Huang, Xiaojing; Marchesini, Stefano; Shapiro, David; Turner, Joshua J; Jacobsen, Chris

2011-01-01

322

Use of x-ray fluorescence and diffraction techniques in studying ancient ceramics of Sri Lanka  

NASA Astrophysics Data System (ADS)

Ceramics were produced for centuries in Sri Lanka for various purposes. Ancient ceramic articles such as pottery, bricks, tiles, sewer pipes, etc, were made from naturally occurring raw materials. Use of X-ray fluorescence (XRF), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) in characterizing of two ancient ceramic samples from two different archaeological sites in Sri Lanka is presented. The information obtained in this manner is used to figure out the ancient ceramic technology, particularly to learn about the raw materials used, the source of raw materials, processing parameters such as firing temperature or binders used in ceramic production. This information then can be used to explore the archaeometric background such as the nature and extent of cultural and technological interaction between different periods of history in Sri Lanka.

Karunaratne, B. S. B.

2012-07-01

323

Synchrotron X-ray diffraction and fluorescence study of the astrolabe  

NASA Astrophysics Data System (ADS)

The astrolabe is an ancient analogue astronomical computing device used for calculations relating to position and time of the observer's location. In its most common form (the planispheric astrolabe), it consists of an engraved plate or series of plates held together and pinned in a housing, the assembly usually being made of brass. The present study describes the use of X-ray diffraction (XRD) and X-ray fluorescence (XRF) in a synchrotron to elucidate the composition of, and fabrication techniques used for, the major component parts of the astrolabe. The synchrotron XRF studies are compared to similar studies made with a handheld XRF instrument and the advantages and disadvantages of both approaches are discussed.

Notis, Michael; Newbury, Brian; Stephenson, Bruce; Stephenson, G. Brian

2013-04-01

324

Automated high pressure cell for pressure jump x-ray diffraction  

SciTech Connect

A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

Brooks, Nicholas J.; Gauthe, Beatrice L. L. E.; Templer, Richard H.; Ces, Oscar; Seddon, John M. [Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Terrill, Nick J. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Rogers, Sarah E. [ISIS, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX (United Kingdom)

2010-06-15

325

Calcination products of gibbsite studied by X-ray diffraction, XPS and solid-state NMR  

NASA Astrophysics Data System (ADS)

The changes caused by heat treatment of gibbsite powder at 300-1473 K were studied using the X-ray diffraction (XRD), X-ray photoemission (XPS) spectra and 27Al magic angle spinning nuclear magnetic resonance spectroscopy (27Al MAS NMR). XRD analysis indicates that the transformation sequence involves the formation of ?-Al2O3 as an intermediate phase between ?- and ?-Al2O3. The crystallite size of ?-Al2O3 is as small as 10 nm. XPS analysis indicates that the ratio of aluminium atoms to oxygen atoms in ?-Al2O3 and ?-Al2O3 increases, whereas the expected ratio is observed in ?-Al2O3. The percentage of AlO4 units in the transition aluminas follows the same behaviour as the ratio of Al/O.

Malki, A.; Mekhalif, Z.; Detriche, S.; Fonder, G.; Boumaza, A.; Djelloul, A.

2014-07-01

326

Investigating crystal microstructure of niobium materials by an x-ray diffraction reciprocal space mapping technique  

NASA Astrophysics Data System (ADS)

An x-ray diffraction reciprocal spacing mapping (RSM) technique was applied to investigate crystal quality of Nb films and bulk materials, relevant to superconducting radio frequency applications. The RSM study used different x-ray penetration depths to study material processes after two different surface treatments: mechanical polishing or energetic condensation (a plasma process). The study revealed the material's microstructure evolution for the two different processes. The RSM plots revealed crystal quality of the materials at different thickness. The novel, differential-depth RSM technique presented in this study substantiated the following facts: (1) For a heteroepitaxial Nb film Nb(100)/MgO(100), a film thickening process, via a cathodic arc-discharge Nb ion deposition (energetic condensation), created a near-perfect single crystal Nb on the surface top layer. (2) For a fine mechanically polished single-crystal bulk Nb material, the microstructure on the top surface layer is more disordered than that at a greater depth.

Yang, Qiguang; Williams, Frances; Zhao, Xin; Reece, Charles; Krishnan, Mahadevan

2014-01-01

327

Object image correction using an X-ray dynamical diffraction Fraunhofer hologram.  

PubMed

Taking into account background correction and using Fourier analysis, a numerical method of an object image correction using an X-ray dynamical diffraction Fraunhofer hologram is presented. An example of the image correction of a cylindrical beryllium wire is considered. A background correction of second-order iteration leads to an almost precise reconstruction of the real part of the amplitude transmission coefficient and improves the imaginary part compared with that without a background correction. Using Fourier analysis of the reconstructed transmission coefficient, non-physical oscillations can be avoided. This method can be applied for the determination of the complex amplitude transmission coefficient of amplitude as well as phase objects, and can be used in X-ray microscopy. PMID:24562568

Balyan, Minas K

2014-03-01

328

X-ray line profile analysis of equal channel angular pressing processed Cu  

NASA Astrophysics Data System (ADS)

The effect of equal channel angular pressing on the microstructure of copper samples was studied by X-ray line profile analysis. Pure Cu samples were processed by equal channel angular pressing with 3 passes in route A. Samples were taken from the vicinity of the channel intersection, and along a profile across the deformation zone, microhardness and XRD measurements were performed. For the high resolution line profile analysis of the diffraction spectra, convolutional-multiple-whole-profile CMWP method was applied, dislocation density and grain size were calculated, furthermore the density of twin boundaries were determined. Results show a rearrangement in the dislocations in the third pass leading to a rise in the density of twin boundaries.

Jóni, B.; Gonda, V.; Verö, B.; Ungár, T.

2014-08-01

329

Thirty-Meter X-Ray Pencil Beam Line at the Institute of Space and Astronautical Science  

Microsoft Academic Search

A 30-m-long X-ray beam line has been built at the Institute of Space and Astronautical Science (ISAS) to evaluate the performance of X-ray optical instruments for space programs, in particular for the X-ray telescope onboard the Astro-D (Asca) satellite. This beam line consists of an X-ray generator, a 30-m-long vacuum duct, and measuring chambers. Strong and stable X-ray pencil beams

Hideyo Kunieda; Yoshiyuki Tsusaka; Hisanori Suzuki; Yasushi Ogasaka; Hisamitsu Awaki; Yuzuru Tawara; Koujun Yamashita; Takashi Yamazaki; Masayuki Itoh; Tsuneo Kii; Fumiyoshi Makino; Yoshiaki Ogawara; Hiroshi Tsunemi; Kiyoshi Hayashida; Susumu Nomoto; Mikio Wada; Emi Miyata; Isamu Hatsukade

1993-01-01

330

A novel wafer-scale CMOS APS X-ray detector for breast cancer diagnosis using X-ray diffraction studies  

NASA Astrophysics Data System (ADS)

The current study uses a novel large area (12.8 cm × 13.1 cm) complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) X-ray detector, named Dynamic range Adjustable for Medical Imaging Technology (DynAMITe), for breast cancer diagnosis. The detector consists of two geometrically superimposed grids: a) 2560 × 2624 fine-pitch grid of pixels (50 ?m pitch), named Sub-Pixels (SP camera), for low intrinsic noise and high spatial resolution and b) 1280 × 1312 large-pitch grid of pixels (100 ?m pitch), named Pixels (P camera), for high dynamic range. X-ray performance characterization measurements show that the detective quantum efficiency (DQE) of the SP camera is in the range 0.7-0.75 at low spatial frequencies using a tungsten (W) anode X-ray source at 28 kV. Hence, the detector is suitable for mammography. Furthermore, we used the SP camera to combine mammograms with angle dispersive X-ray diffraction (ADXRD) measurements in order to apply the X-ray biopsy concept in one examination. The results show that ADXRD technique indicates the presence of cancer in suspicious areas on the mammogram. Hence, it could be used to determine the region affected by cancer and assist in planning surgery. This study is the proof of concept that mammography and ADXRD can be combined in one examination.

Konstantinidis, A.; Zheng, Y.; Philip, D.; Vinnicombe, S.; Speller, R.

2012-12-01

331

Scanning Coherent X-ray Diffraction Imaging of GdFe Magnetic Multilayers  

NASA Astrophysics Data System (ADS)

Crucial to understanding fundamental physics puzzles such as colossal magnetoresistance and developing future technologies for magnetic data storage is an understanding of the nanoscale behavior of magnetism. Probes with the ability to see beyond surfaces on this length scale, ultimately on ultrafast time scales, would greatly enhance this understanding. Coherent X-ray Diffraction Imaging (CXDI) is a promising new technique with wavelength-limited resolution that can probe deeply beyond surfaces. We studied the evolution of ``worm'' domains in a ferrimagnetic GdFe multilayer film as a function of applied field using CXDI. Ferromagnetic domains in the multilayer produce high contrast speckle when the film is illuminated with linearly polarized coherent x-rays resonant at the Gd M5 edge. This diffraction is purely magnetic since the sample is electronically amorphous. We recorded coherent diffraction data by scanning overlapping regions on the sample. These diverse diffraction patterns are then numerically inverted using ptychographic iterative algorithms to give a high resolution map of the ferromagnetic domain configuration.

Tripathi, A.; Kim, S. S.; Mohanty, J.; Dietze, S.; Shipton, E.; Chan, K.; Fullerton, E.; Shpyrko, O.; McNulty, I.

2010-03-01

332

Polycrystalline solids under nonhydrostatic compression: Determination of strength from x-ray diffraction data  

NASA Astrophysics Data System (ADS)

A polycrystalline sample compressed in a diamond anvil cell (DAC) without any pressure transmitting medium develops a stress state at the centre of the sample that is axially symmetric about the load axis. The axial stress component is larger than the radial component and the difference t between the two is taken as a measure of the compressive strength of the sample material at a confining pressure that equals the mean normal stress. A proper analysis of the diffraction data yields t. The data taken with the radial diffraction geometry, wherein the incident x-ray beam is perpendicular to the load axis of the DAC, give reliable estimates of strength. The diffraction data obtained with the conventional geometry, wherein the incident x-ray beam passes parallel to the DAC axis, provide reasonable estimates of strength. However, even in this case, reliable strength data can be obtained by combining the measured pressure-volume data under nonhydrostatic compression and the hydrostat derived from an independent source. The determination of strength from high pressure diffraction data is discussed.

Singh, A. K.

2014-05-01

333

Theory of radial X-ray Diffraction from a Polycrystalline Sample Undergoing Plastic Deformation  

SciTech Connect

Theory of lattice strain in a polycrystalline aggregate under deviatoric stress is extended to include the influence of ongoing plastic deformation. When deviatoric stress is applied to a polycrystalline material at high temperatures (or above the yield stress), applied macroscopic stress is redistributed to individual grains by plastic deformation according to their orientations with respect to the macroscopic stress and plastic anisotropy of a given crystal. This microstress causes elastic deformation of individual grains that can be measured by x-ray diffraction. Consequently, the observed lattice strain depends on two material properties, viscosity (plasticity) and elastic compliance as well as the applied macroscopic stress and the stress-strain distribution among various grains. The influence of plastic deformation on lattice strain is analyzed using an anisotropic and nonlinear power-law constitutive relationship. In this model, the dependence of inferred macroscopic stress on the crystallographic orientation of diffraction plane (hkl) comes from elastic and plastic anisotropy of a crystal. In many materials, plastic anisotropy dominates over elastic anisotropy. This explains the observed large dependence of inferred stress on the diffraction plane and means that the determination of elastic anisotropy is difficult when plastic deformation occurs with anisotropic plasticity. When elastic anisotropy is known, plastic anisotropy of single crystal and/or stress-strain distribution in a deformed polycrystal can be determined from radial x-ray diffraction using the present model. Some examples are presented using the data on MgO.

S Karato

2011-12-31

334

KOTOBUKI-1 apparatus for cryogenic coherent X-ray diffraction imaging  

NASA Astrophysics Data System (ADS)

We have developed an experimental apparatus named KOTOBUKI-1 for use in coherent X-ray diffraction imaging experiments of frozen-hydrated non-crystalline particles at cryogenic temperature. For cryogenic specimen stage with small positional fluctuation for a long exposure time of more than several minutes, we here use a cryogenic pot cooled by the evaporation cooling effect for liquid nitrogen. In addition, a loading device is developed to bring specimens stored in liquid nitrogen to the specimen stage in vacuum. The apparatus allows diffraction data collection for frozen-hydrated specimens at 66 K with a positional fluctuation of less than 0.4 ?m and provides an experimental environment to easily exchange specimens from liquid nitrogen storage to the specimen stage. The apparatus was developed and utilized in diffraction data collection of non-crystalline particles with dimensions of ?m from material and biological sciences, such as metal colloid particles and chloroplast, at BL29XU of SPring-8. Recently, it has been applied for single-shot diffraction data collection of non-crystalline particles with dimensions of sub-?m using X-ray free electron laser at BL3 of SACLA.

Nakasako, Masayoshi; Takayama, Yuki; Oroguchi, Tomotaka; Sekiguchi, Yuki; Kobayashi, Amane; Shirahama, Keiya; Yamamoto, Masaki; Hikima, Takaaki; Yonekura, Koji; Maki-Yonekura, Saori; Kohmura, Yoshiki; Inubushi, Yuichi; Takahashi, Yukio; Suzuki, Akihiro; Matsunaga, Sachihiro; Inui, Yayoi; Tono, Kensuke; Kameshima, Takashi; Joti, Yasumasa; Hoshi, Takahiko

2013-09-01

335

Characterization of an Yb:LuVO 4 single crystal using X-ray topography, high-resolution X-ray diffraction, and X-ray photoelectron spectroscopy  

Microsoft Academic Search

Knowledge on the defect and electronic structure allows for improved modeling of material properties. A short literature review has shown that the information on defect structure of rare earth orthovanadate single crystals is limited. In this paper, defect and electronic structure of a needle-shaped Yb:LuVO4 single crystal grown by the slow cooling method have been studied by means of X-ray

W. Paszkowicz; P. Romanowski; J. Bak-Misiuk; W. Wierzchowski; K. Wieteska; W. Graeff; R. J. Iwanowski; M. H. Heinonen; O. Ermakova; H. Dabkowska

2011-01-01

336

X-ray diffraction from isolated and strongly aligned gas-phase molecules with a free-electron laser  

E-print Network

We report experimental results on x-ray diffraction of quantum-state-selected and strongly aligned ensembles of the prototypical asymmetric rotor molecule 2,5-diiodobenzonitrile using the Linac Coherent Light Source. The experiments demonstrate pioneering steps toward a new bottom-up approach to diffractive imaging of distinct structures of individual, isolated gas-phase molecules. We confirm several key ingredients of single molecule diffraction experiments: the abilities to detect and count individual scattered x-ray photons in single shot diffraction data, to deliver state-selected, e.g., structural-isomer-selected, ensembles of molecules to the x-ray interaction volume, and to strongly align the scattering molecules. Our approach, using ultrashort x-ray pulses, is suitable to study ultrafast dynamics of isolated molecules.

Küpper, Jochen; Holmegaard, Lotte; Filsinger, Frank; Rouzée, Arnaud; Rolles, Daniel; Rudenko, Artem; Johnsson, Per; Martin, Andrew V; Adolph, Marcus; Aquila, Andrew; Bajt, Saša; Barty, Anton; Bostedt, Christoph; Bozek, John; Caleman, Carl; Coffee, Ryan; Coppola, Nicola; Delmas, Tjark; Epp, Sascha; Erk, Benjamin; Foucar, Lutz; Gorkhover, Tais; Gumprecht, Lars; Hartmann, Andreas; Hartmann, Robert; Hauser, Günter; Holl, Peter; Hömke, Andre; Kimmel, Nils; Krasniqi, Faton; Kühnel, Kai-Uwe; Maurer, Jochen; Messerschmidt, Marc; Mosshammer, Robert; Reich, Christian; Rudek, Benedikt; Santra, Robin; Schlichting, Ilme; Schmidt, Carlo; Schorb, Sebastian; Schulz, Joachim; Soltau, Heike; Strüder, Lothar; Thøgersen, Jan; Vrakking, Marc J J; Weidenspointner, Georg; White, Thomas A; Wunderer, Cornelia; Meijer, Gerard; Ullrich, Joachim; Stapelfeldt, Henrik; Chapman, Henry N

2013-01-01

337

X-Ray Diffraction from Isolated and Strongly Aligned Gas-Phase Molecules with a Free-Electron Laser  

NASA Astrophysics Data System (ADS)

We report experimental results on x-ray diffraction of quantum-state-selected and strongly aligned ensembles of the prototypical asymmetric rotor molecule 2,5-diiodobenzonitrile using the Linac Coherent Light Source. The experiments demonstrate first steps toward a new approach to diffractive imaging of distinct structures of individual, isolated gas-phase molecules. We confirm several key ingredients of single molecule diffraction experiments: the abilities to detect and count individual scattered x-ray photons in single shot diffraction data, to deliver state-selected, e.g., structural-isomer-selected, ensembles of molecules to the x-ray interaction volume, and to strongly align the scattering molecules. Our approach, using ultrashort x-ray pulses, is suitable to study ultrafast dynamics of isolated molecules.

Küpper, Jochen; Stern, Stephan; Holmegaard, Lotte; Filsinger, Frank; Rouzée, Arnaud; Rudenko, Artem; Johnsson, Per; Martin, Andrew V.; Adolph, Marcus; Aquila, Andrew; Bajt, Saša; Barty, Anton; Bostedt, Christoph; Bozek, John; Caleman, Carl; Coffee, Ryan; Coppola, Nicola; Delmas, Tjark; Epp, Sascha; Erk, Benjamin; Foucar, Lutz; Gorkhover, Tais; Gumprecht, Lars; Hartmann, Andreas; Hartmann, Robert; Hauser, Günter; Holl, Peter; Hömke, Andre; Kimmel, Nils; Krasniqi, Faton; Kühnel, Kai-Uwe; Maurer, Jochen; Messerschmidt, Marc; Moshammer, Robert; Reich, Christian; Rudek, Benedikt; Santra, Robin; Schlichting, Ilme; Schmidt, Carlo; Schorb, Sebastian; Schulz, Joachim; Soltau, Heike; Spence, John C. H.; Starodub, Dmitri; Strüder, Lothar; Thøgersen, Jan; Vrakking, Marc J. J.; Weidenspointner, Georg; White, Thomas A.; Wunderer, Cornelia; Meijer, Gerard; Ullrich, Joachim; Stapelfeldt, Henrik; Rolles, Daniel; Chapman, Henry N.

2014-02-01

338

Advanced combined application of micro-X-ray diffraction/micro-X-ray fluorescence with conventional techniques for the identification of pictorial materials from Baroque Andalusia paintings.  

PubMed

The process of investigating paintings includes the identification of materials to solve technical and historical art questions, to aid in the deduction of the original appearance, and in the establishment of the chemical and physical conditions for adequate restoration and conservation. In particular, we have focused on the identification of several samples taken from six famous canvases painted by Pedro Atanasio Bocanegra, who created a very special collection depicting the life of San Ignacio, which is located in the church of San Justo y Pastor of Granada, Spain. The characterization of the inorganic and organic compounds of the textiles, preparation layers, and pictorial layers have been carried out using an XRD diffractometer, SEM observations, EDX spectrometry, FT-IR spectrometry (both in reflection and transmission mode), pyrolysis/gas chromatography/mass spectrometry and synchrotron-based micro-X-ray techniques. In this work, the advantages over conventional X-ray diffraction of using combined synchrotron-based micro-X-ray diffraction and micro-X-ray fluorescence in the identification of multi-layer paintings is demonstrated. PMID:19782194

Herrera, L K; Montalbani, S; Chiavari, G; Cotte, M; Solé, V A; Bueno, J; Duran, A; Justo, A; Perez-Rodriguez, J L

2009-11-15

339

Comparison of a CCD and an APS for soft X-ray diffraction  

Microsoft Academic Search

We compare a new CMOS Active Pixel Sensor (APS) to a Princeton Instruments PIXIS-XO: 2048B Charge Coupled Device (CCD) with soft X-rays tested in a synchrotron beam line at the Diamond Light Source (DLS). Despite CCDs being established in the field of scientific imaging, APS are an innovative technology that offers advantages over CCDs. These include faster readout, higher operational

Graeme Stewart; R Bates; A Blue; A Clark; S S Dhesi; D Maneuski; J Marchal; P Steadman; N Tartoni; R Turchetta

2011-01-01

340

Discovery of an X-ray Violently Variable Broad Absorption Line Quasar  

NASA Technical Reports Server (NTRS)

In this letter, we report on a quasar that is violently variable in the X-rays, XVV. It is also a broad absorption line quasar (BALQSO) that exhibits both high ionization and low ionization UV absorption lines (LoBALQSO). It is very luminous in the X-rays (approximately 10(exp 46) ergs s(sup -l) over the entire X-ray band). Surprisingly, this does not over ionize the LoBAL outflow. The X-rays vary by a factor of two within minutes in the quasar rest frame, which is shorter than 1/30 of the light travel time across a scale length equal to the black hole radius. We concluded that the X-rays are produced in a relativistic jet beamed toward earth in which variations in the Doppler enhancement produce the XVV behavior.

Ghosh, Kajal K.; Gutierrez, Carlos M.; Punsly, Brian; Chevallier, Loic; Goncalves, Anabela C.

2006-01-01

341

Furthering the understanding of silicate-substitution in ?-tricalcium phosphate: an X-ray diffraction, X-ray fluorescence and solid-state nuclear magnetic resonance study.  

PubMed

High-purity (SupT) and reagent-grade (ST), stoichiometric and silicate-containing ?-tricalcium phosphate (?-TCP: ST0/SupT0 and Si-TCP x=0.10: ST10/SupT10) were prepared by solid-state reaction based on the substitution mechanism Ca3(PO4)(2-x)(SiO4)x. Samples were determined to be phase pure by X-ray diffraction (XRD), and Rietveld analysis performed on the XRD data confirmed inclusion of Si in the ?-TCP structure as determined by increases in unit cell parameters; particularly marked increases in the b-axis and ?-angle were observed. X-ray fluorescence (XRF) confirmed the presence of expected levels of Si in Si-TCP compositions as well as significant levels of impurities (Mg, Al and Fe) present in all ST samples; SupT samples showed both expected levels of Si and a high degree of purity. Phosphorus ((31)P) magic-angle-spinning solid-state nuclear magnetic resonance (MAS NMR) measurements revealed that the high-purity reagents used in the synthesis of SupT0 can resolve the 12 expected peaks in the (31)P spectrum of ?-TCP compared to the low-purity ST0 that showed significant spectral line broadening; line broadening was also observed with the inclusion of Si which is indicative of induced structural disorder. Silicon ((29)Si) MAS NMR was also performed on both Si-TCP samples which revealed Q(0) species of Si with additional Si Q(1)/Q(2) species that may indicate a potential charge-balancing mechanism involving the inclusion of disilicate groups; additional Q(4) Si species were also observed, but only for ST10. Heating and cooling rates were briefly investigated by (31)P MAS NMR which showed no significant line broadening other than that associated with the emergence of ?-TCP which was only realised with the reagent-grade sample ST0. This study provides an insight into the structural effects of Si-substitution in ?-TCP and could provide a basis for understanding how substitution affects the physicochemical properties of the material. PMID:24287162

Duncan, J; Hayakawa, S; Osaka, A; MacDonald, J F; Hanna, J V; Skakle, J M S; Gibson, I R

2014-03-01

342

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

343

A method of rapidly obtaining concentration-depth profiles from X-ray diffraction  

NASA Technical Reports Server (NTRS)

A broadened diffraction peak, or intensity band, is observed in the case diffraction from a nonhomogeneous phase in which the variations in compositions result in a range of lattice spacings. An intriguing aspect regarding the relationship between the X-ray diffraction band and the composition-depth profile is the hypersensitivity of the intensity band to the shape of the profile. A number of investigators have sought to use this sensitivity to construct high-precision profiles. Difficulties encountered are related to complications due to intensity broadening, and prohibitive computational requirements. Simulation techniques have provided the most accurate interpretation of the intensity band. However, the involved calculations have been prohibitively long. The present study discusses a technique which has simple computational requirements and is as accurate and flexible as the simulation techniques.

Wiedemann, K. E.; Unnam, J.

1985-01-01

344

Scanning Coherent X-ray Diffraction Imaging of Pinned GdFe Magnetic Multilayers  

NASA Astrophysics Data System (ADS)

Crucial to understanding fundamental physics puzzles such as colossal magnetoresistance and developing future technologies for magnetic data storage is an understanding of the nanoscale behavior of magnetism. We study Gd/Fe multilayers exhibiting ordered stripes due to perpendicular magnetic anisotropy (PMA) that are pinned by artificial Au patterns. Using element sensitivity and depth resolution of Coherent X-ray Diffraction Imaging (CXDI), we investigate the magnetic domain structure, observing the role of disorder in the formation and stability of the magnetic domains. We recorded coherent diffraction data by scanning overlapping regions on the sample using linearly polarized light both on and off the Gd M5 resonant edge These diffraction patterns are then numerically inverted using ptychographic iterative algorithms to give a high resolution map of the Au structure and the ferromagnetic domain configuration as we scan through the magnetization hysteresis loop.

Dietze, Sebastian; Marsh, Moses; Tripathi, Ashish; Uhlir, Vojtech; Fullerton, Eric; Vine, David; McNulty, Ian; Shpyrko, Oleg

2012-02-01

345

Standing-wave effects in grazing-incidence x-ray diffraction from polycrystalline multilayers  

NASA Astrophysics Data System (ADS)

The intensity of x-ray diffraction from a polycrystalline multilayer in a grazing-incidence scattering geometry is modulated by a standing wave created by the interference of the radiation transmitted through the multilayer stack with the wave field specularly reflected from the superlattice interfaces. Similarly, the radiation being diffracted from the polycrystalline structure is reflected specularly from the interfaces and a standing-wave interference pattern results as well. This effect is demonstrated by a series of diffraction measurements on C /Ni periodic multilayers; the experimental data have been modeled using the distorted-wave Born approximation and a very good correspondence with the experiments was achieved. The method was used for the study of the profiles of the crystallite sizes and strains in multilayers.

Kr?má?, J.; Holý, V.; Horák, L.; Metzger, T. H.; Sobota, J.

2008-02-01

346

Fundamental parameters approach applied to focal construct geometry for X-ray diffraction  

NASA Astrophysics Data System (ADS)

A novel geometry for the acquisition of powder X-ray diffraction data, referred to as focal construct geometry (FCG), is presented. Diffraction data obtained by FCG have been shown to possess significantly enhanced intensity due to the hollow tube beam arrangement utilized. In contrast to conventional diffraction, the detector is translated to collect images along a primary axis and record the location of Bragg maxima. These high intensity condensation foci are unique to FCG and appear due to the convergence of Debye cones at single points on the primary axis. This work focuses on a two dimensional, fundamental parameter's approach to simulate experimental data and subsequently aid with interpretation. This convolution method is shown to favorably reproduce the experimental diffractograms and can also accommodate preferred orientation effects in some circumstances.

Rogers, K.; Evans, P.; Prokopiou, D.; Dicken, A.; Godber, S.; Rogers, J.

2012-10-01

347

X-ray diffraction analysis of residual stress in zirconia dental composites  

NASA Astrophysics Data System (ADS)

Dental restoration ceramic is a complex system to be characterized. Beside its essential biocompatibility, and pleasant appearance, it requires being mechanically strong in a catastrophic loading environment. Any design is restricted with geometry boundary and material property limits. Inspired by natural teeth, a multilayer ceramic is a smart way of achieving an enhanced restoration. Bi-layers of zirconia core covered by porcelain are known as one of the best multilayer restorations. Residual stresses may be introduced into a bi-layer dental ceramic restoration during its entire manufacturing process due to thermal expansion and elastic property mismatch. It is impossible to achieve a free of residual stresses bi-layer zirconia-porcelain restoration. The idea is to take the advantage of residual stress in design in such a way to prevent the crack initiation and progression. The hypothesis is a compressive residual stress at external contact surface would be enabling the restoration to endure a greater tensile stress. Optimizing the layers thickness, manufacturing process, and validating 3D simulations require development of new techniques of thickness, residual stresses and phase transformation measurement. In the present work, a combined mirco-tomography and finite element based method were adapted for thickness measurement. Two new 2D X-ray diffraction based techniques were adapted for phase transformation area mapping and combined phase transformation and residual stress measurement. Concerning the complex geometry of crown, an efficient method for X-ray diffraction data collection mapping on a given curved surface was developed. Finally a novel method for 3D dimensional x-ray diffraction data collection and visualization were introduced.

Allahkarami, Masoud

348

Laboratory manual: mineral X-ray diffraction data retrieval/plot computer program  

USGS Publications Warehouse

The Mineral X-Ray Diffraction Data Retrieval/Plot Computer Program--XRDPLT (VanTrump and Hauff, 1976a) is used to retrieve and plot mineral X-ray diffraction data. The program operates on a file of mineral powder diffraction data (VanTrump and Hauff, 1976b) which contains two-theta or 'd' values, and intensities, chemical formula, mineral name, identification number, and mineral group code. XRDPLT is a machine-independent Fortran program which operates in time-sharing mode on a DEC System i0 computer and the Gerber plotter (Evenden, 1974). The program prompts the user to respond from a time-sharing terminal in a conversational format with the required input information. The program offers two major options: retrieval only; retrieval and plot. The first option retrieves mineral names, formulas, and groups from the file by identification number, by the mineral group code (a classification by chemistry or structure), or by searches based on the formula components. For example, it enables the user to search for minerals by major groups (i.e., feldspars, micas, amphiboles, oxides, phosphates, carbonates) by elemental composition (i.e., Fe, Cu, AI, Zn), or by a combination of these (i.e., all copper-bearing arsenates). The second option retrieves as the first, but also plots the retrieved 2-theta and intensity values as diagrammatic X-ray powder patterns on mylar sheets or overlays. These plots can be made using scale combinations compatible with chart recorder diffractograms and 114.59 mm powder camera films. The overlays are then used to separate or sieve out unrelated minerals until unknowns are matched and identified.

Hauff, Phoebe L.; VanTrump, George

1976-01-01

349

X-ray diffraction and reflectometry studies of porous silicon:. n-type layers and holographic gratings  

NASA Astrophysics Data System (ADS)

X-ray diffraction and reflectometry allows the measurements of various parameters (thickness, porosity, roughness and strain) of thin layers of porous silicon. Measurements on n-type porous silicon layers of different doping give very different results: for lightly doped samples, the layer properties vary smoothly as a function of formation time, while for heavily doped samples several regimes are observed for short formation times. X-ray satellites have been observed in the X-ray reflexion or diffraction from holographic gratings.

Chamard, V.; Dolino, G.; Lérondel, G.; Setzu, S.

1998-06-01

350

Fixture for supporting and aligning a sample to be analyzed in an x-ray diffraction apparatus  

DOEpatents

A fixture is provided for supporting and aligning small samples of material on a goniometer for x-ray diffraction analysis. A sample-containing capillary is accurately positioned for rotation in the x-ray beam by selectively adjusting the fixture to position the capillary relative to the x and y axes thereof to prevent wobble and position the sample along the z axis or the axis of rotation. By employing the subject fixture relatively small samples of materials can be analyzed in an x-ray diffraction apparatus previously limited to the analysis of much larger samples.

Green, L.A.; Heck, J.L. Jr.

1985-04-23

351

Fixture for supporting and aligning a sample to be analyzed in an X-ray diffraction apparatus  

DOEpatents

A fixture is provided for supporting and aligning small samples of material on a goniometer for X-ray diffraction analysis. A sample-containing capillary is accurately positioned for rotation in the X-ray beam by selectively adjusting the fixture to position the capillary relative to the x and y axes thereof to prevent wobble and position the sample along the z axis or the axis of rotation. By employing the subject fixture relatively small samples of materials can be analyzed in an X-ray diffraction apparatus previously limited to the analysis of much larger samples.

Green, Lanny A. (Knoxville, TN); Heck, Jr., Joaquim L. (Knoxville, TN)

1987-01-01

352

Picosecond acoustic response of a laser-heated gold-film studied with time-resolved x-ray diffraction  

NASA Astrophysics Data System (ADS)

We apply time-resolved x-ray diffraction using ultrashort x-ray pulses from a laser-produced plasma to probe the picosecond acoustic response of a thin laser-heated gold film. Measurements of the temporal changes in the angular distribution of diffracted x-rays provide direct quantitative information on the transient evolution of lattice strain. This allows to disentangle electronic and thermal pressure contributions driving lattice expansion after impulsive laser excitation. The electron-lattice energy equilibration time ?E=(5±0.3) ps as well as the electronic Grüneisen parameter ?e=(1.48±0.3) have been determined.

Nicoul, Matthieu; Shymanovich, Uladzimir; Tarasevitch, Alexander; von der Linde, Dietrich; Sokolowski-Tinten, Klaus

2011-05-01

353

Tracking the motion of charges in a terahertz light field by femtosecond X-ray diffraction.  

PubMed

In condensed matter, light propagation near resonances is described in terms of polaritons, electro-mechanical excitations in which the time-dependent electric field is coupled to the oscillation of charged masses. This description underpins our understanding of the macroscopic optical properties of solids, liquids and plasmas, as well as of their dispersion with frequency. In ferroelectric materials, terahertz radiation propagates by driving infrared-active lattice vibrations, resulting in phonon-polariton waves. Electro-optic sampling with femtosecond optical pulses can measure the time-dependent electrical polarization, providing a phase-sensitive analogue to optical Raman scattering. Here we use femtosecond time-resolved X-ray diffraction, a phase-sensitive analogue to inelastic X-ray scattering, to measure the corresponding displacements of ions in ferroelectric lithium tantalate, LiTaO(3). Amplitude and phase of all degrees of freedom in a light field are thus directly measured in the time domain. Notably, extension of other X-ray techniques to the femtosecond timescale (for example, magnetic or anomalous scattering) would allow for studies in complex systems, where electric fields couple to multiple degrees of freedom. PMID:16900195

Cavalleri, A; Wall, S; Simpson, C; Statz, E; Ward, D W; Nelson, K A; Rini, M; Schoenlein, R W

2006-08-10

354

Tracking the motion of charges in a terahertz light field byfemtosecond X-ray diffraction  

SciTech Connect

In condensed matter, light propagation near resonances isdescribed in terms of polaritons, electro-mechanical excitations in whichthe time-dependent electric field is coupled to the oscillation ofcharged masses. This description under pins our understanding of themacroscopic optical properties of solids, liquids and plasmas, as well asof their dispersion with frequency. In ferroelectric materials, terahertzradiation propagates by driving infrared-active lattice vibrations,resulting in phononpolariton waves. Electro-optic sampling withfemtosecond optical pulses can measure the time-dependent electricalpolarization, providing a phase-sensitive analogue to optical Ramanscattering. Here we use femtosecond time-resolved X-ray diffraction, aphase-sensitive analogue to inelastic X-ray scattering, to measure thecorresponding displacements of ions in ferroelectric lithium tantalate,LiTaO3. Amplitude and phase of all degrees of freedom in a light fieldare thus directly measured in the time domain. Notably, extension ofother X-ray techniques to the femtosecond timescale (for example,magnetic or anomalous scattering) would allow for studies in complexsystems, where electric fields couple to multiple degrees offreedom.

Cavalleri, A.; Wall, S.; Simpson, C.; Statz, E.; Ward, D.W.; Nelson, K.A.; Rini, M.; Schoenlein, R.W.

2006-07-01

355

Spontaneous soft x-ray fluorescence from a superlattice under Kossel diffraction conditions  

NASA Astrophysics Data System (ADS)

The present study gives the proof of principle of a technique that is an extension of Kossel diffraction both from crystals to superlattices and toward the soft x-ray region, allowing the characterization of the interfaces within a periodic structure. We measure the intensity of the Co L? and Mg K? characteristic fluorescence emissions from a Mg/Co superlattice upon soft x-ray excitation. The observation is made so that the angle between the sample surface and the detection direction is scanned around the first and second Bragg peaks of the fluorescence emissions. Clear modulations of the emitted intensities are observed and well reproduced by simulations based on the reciprocity theorem and assuming a perfect stack. The present work gives evidence that such a superlattice plays the role of an optical cavity for the spontaneous emission generated within the stack. This should also be the case for stimulated emission, which when combined with pumping free electron laser, will open the road to innovative x-ray distributed feedback lasers.

Jonnard, P.; Yuan, Y.-Y.; Le Guen, K.; André, J.-M.; Zhu, J.-T.; Wang, Z.-S.; Bridou, F.

2014-08-01

356

Investigation of Solid Phase Composition on Tablet Surfaces by Grazing Incidence X-ray Diffraction  

Microsoft Academic Search

Purpose  To investigate solid state transformations of drug substances during compaction using grazing incidence X-ray diffraction\\u000a (GIXD).\\u000a \\u000a \\u000a \\u000a \\u000a Methods  The solid forms of three model drugs–theophylline (TP), nitrofurantoin (NF) and amlodipine besylate (AMB)–were compacted at\\u000a different pressures (from 100 to 1000 MPa); prepared tablets were measured using GIXD. After the initial measurements of freshly\\u000a compacted tablets, tablets were subjected to suitable recrystallization treatment, and

Vishal Koradia; Mikko Tenho; Heidi Lopez de Diego; Michiel Ringkjøbing-Elema; Jørn Møller-Sonnergaard; Jarno Salonen; Vesa-Pekka Lehto; Jukka Rantanen

357

Darwin's approach to X-ray diffraction on lateral crystalline structures.  

PubMed

Darwin's dynamical theory of X-ray diffraction is extended to the case of lateral (i.e., having a finite length in the lateral direction) crystalline structures. This approach allows one to calculate rocking curves as well as reciprocal-space maps for lateral crystalline structures having a rectangular cross section. Numerical modelling is performed for these structures with different lateral sizes. It is shown that the kinematical approximation is valid for thick crystalline structures having a small length in the lateral direction. PMID:24419171

Punegov, Vasily I; Kolosov, Sergey I; Pavlov, Konstantin M

2014-01-01

358

Blind deconvolution of x-ray diffraction profiles by using high-order statistics  

NASA Astrophysics Data System (ADS)

A high-order statistical-based, blind deconvolution algorithm is proposed for x-ray powder diffraction profiles. Maximizing the kurtosis amplitude of the deconvolved data ensures that only the data with maximized kurtosis amplitude is extracted. The ill-posed nature of deconvolution is, thus, bypassed. Using simulation and experiments, this method is seen to be very robust with respect to noise. The profile resolution is enhanced considerably, and the deconvolved profile fits the pseudo-Voigt profile nicely. However, noise is enhanced in the deconvolved data, so the algorithm may be invalid for experimental data with low signal-to-noise.

Yuan, Jinghe

2009-07-01

359

X-ray diffraction studies and equation of state of methane at 202 GPa  

SciTech Connect

Solid methane (CH{sub 4}) was compressed up to 202 GPa at 300 K in a diamond-anvil cell. The crystal structure and equation of state over this entire range were determined from angle dispersive X-ray diffraction results. CH{sub 4} undergoes phase transitions from rhombohedral to a simple cubic phase at 19 GPa and from simple cubic to a higher pressure cubic phase at approximately 94 GPa. This higher pressure cubic phase was stable to the maximum pressure investigated. Combined with previous optical measurements, it was found that at room temperature compressed CH{sub 4} remains an insulator with cubic structure to 202 GPa.

Sun, Liling; Yi, Wei; Wang, Lin; Shu, Jinfu; Sinogeikin, Stas; Meng, Yue; Shen, Guoyin; Bai, Ligang; Li, Yanchuan; Liu, Jing; Mao, Ho-kwang; Mao, Wendy L.; (Stanford); (CIW); (Chinese Aca. Sci.)

2009-04-22

360

High Pressure X-ray Diffraction Study on Icosahedral Boron Arsenide (B12As2)  

SciTech Connect

The high pressure properties of icosahedral boron arsenide (B12As2) were studied by in situ X-ray diffraction measurements at pressures up to 25.5 GPa at room temperature. B12As2 retains its rhombohedral structure; no phase transition was observed in the pressure range. The bulk modulus was determined to be 216 GPa with the pressure derivative 2.2. Anisotropy was observed in the compressibility of B12As2-c-axis was 16.2% more compressible than a-axis. The boron icosahedron plays a dominant role in the compressibility of boron-rich compounds.

J Wu; H Zhu; D Hou; C Ji; C Whiteley; J Edgar; Y Ma

2011-12-31

361

Investigation of hepatic fibrosis in rats with x-ray diffraction enhanced imaging  

SciTech Connect

X-ray diffraction enhanced imaging (DEI) is a phase contrast technique that generates excellent contrast of biological soft tissues compared to conventional absorption radiography. We explore the application of DEI in the diagnosis of hepatic fibrosis. The produced refraction contrast images of fibrous rat liver samples show clearly abnormal liver architectures. Moreover, by comparing to histological pictures, different stages of fibrosis are discriminated, and the corresponding morphological features are analyzed. Besides, quantitative analyses of texture features are presented. The results reported herein show that DEI can be a potential noninvasive technique to diagnose and stage hepatic fibrosis.

Li Hui [School of Biomedical Engineering, Capital Medical University, Beijing 100069 (China); Department of Medical Physics, Peking University Health Science Center, Beijing 100191 (China); Zhang Lu; Wang Xueyan; Luo Shuqian [School of Biomedical Engineering, Capital Medical University, Beijing 100069 (China); Wang Tailing [Department of Pathology, China-Japan Friendship Hospital, Beijing 100029 (China); Wang Baoen; Zhao Xinyan [Liver Research Center, Beijing Friendship Hospital, Beijing 100050 (China)

2009-03-23

362

Effect of epilayer microstructure on shape of X-Ray diffraction peaks  

NASA Astrophysics Data System (ADS)

The X-Ray diffraction (XRD) reflections from epitaxial layers with various microstructures have been measured in the Bragg and Laue geometries. The shapes of XRD peaks measured in the ? and ?-2? scan modes have been analyzed using the approximation by the Voigt function. It is shown that, for the structures with more regular dislocation systems, the Gaussian component predominates, whereas a more chaotic distribution of dislocations leads to an increase in the Lorentzian component. Far on the wings of XRD peaks, the rate of intensity decrease exceeds that predicted by the Voigt function.

Kyutt, R. N.; Dyshekov, A. A.

2011-04-01

363

Synchrotron X-ray diffraction study of ZnTe at high pressure  

NASA Astrophysics Data System (ADS)

ZnTe has been studied at high pressure to 76 GPa and at room temperature in a diamond-anvil cell using angle-dispersive X-ray diffraction technique with synchrotron radiation and an imaging plate detector. The equation-of-state parameters of the two high-pressure phases of ZnTe were for the first time derived to be B0=91.3(7.0) GPa and B0'=0.8(1.0) for the cinnabar-type phase and B0=134(5) GPa and B0'=2.4(1) for the Cmcm-type phase, respectively.

Onodera, A.; Ohtani, A.; Tsuduki, S.; Shimomura, O.

2008-02-01

364

Multinuclear NMR and Powder X-ray Diffraction Studies of Si and Sn Clathrates of Alkali  

SciTech Connect

The Structure I type binary metal clathrates of K/Si, Rb/Si and Cs/Sn have been synthesised and studied by powder X-ray diffraction and solid state NMR. Rietveld analysis shows that in all three materials some of the cages are empty, and that in the Cs/Sn clathrate there are vacancies in the Sn framework. The NMR results yield Knight shifts for 29Si and 39K and confirm that the Cs/Sn clathrate is not conducting. Many of the features of the NMR spectra can be understood in terms of the distributions of atom vacancies.

Ferguson, Michael J.; Moudrakovski, Igor L.; Ratcliffe, C. I.; Tse, John S.

2001-12-01

365

Load transfer in bovine plexiform bone determined by synchrotron x-ray diffraction.  

SciTech Connect

High-energy synchrotron x-ray diffraction (XRD) has been used to quantify load transfer in bovine plexiform bone. By using both wide-angle and small-angle XRD, strains in the mineral as well as the collagen phase of bone were measured as a function of applied compressive stress. We suggest that a greater proportion of the load is borne by the more mineralized woven bone than the lamellar bone as the applied stress increases. With a further increase in stress, load is shed back to the lamellar regions until macroscopic failure occurs. The reported data fit well with reported mechanisms of microdamage accumulation in bovine plexiform bone.

Akhtar, R.; Daymond, M.; Almer, J.; Mummery, P.; The Univ. of Manchester; Queen's Univ.

2008-02-01

366

Real-space interpretation of x-ray-excited Auger-electron diffraction from Cu(001)  

NASA Astrophysics Data System (ADS)

Angle-resolved Auger-electron diffraction from single-crystal Cu(001) surfaces is reported covering the complete range of emission solid angle between inequivalent mirror planes. Contour maps of the Auger-electron polar and azimuthal angular distribution clearly show the relationship of the measured intensity to low-index real-space crystallographic axes. An experimental approach is described which provides a means for surface-sensitive structure determinations in x-ray-excited electron spectroscopy by comparison to the direct lattice using geometrical constructions.

Li, H.; Tonner, B. P.

1988-03-01

367

Crystallization and preliminary X-ray diffraction analysis of red clover necrotic mosaic virus  

PubMed Central

Red clover necrotic mosaic virus (RCNMV) is a species that belongs to the Tombusviridae family of plant viruses with a T = 3 icosahedral capsid. RCNMV virions were purified and were crystallized for X-ray analysis using the hanging-drop vapor-diffusion method. Self-rotation functions and systematic absences identified the space group as I23, with two virions in the unit cell. The crystals diffracted to better than 4?Å resolution but were very radiation-sensitive, causing rapid decay of the high-resolution reflections. The data were processed to 6?Å in the analysis presented here. PMID:21045294

Martin, Stanton L.; Guenther, Richard H.; Sit, Tim L.; Swartz, Paul D.; Meilleur, Flora; Lommel, Steven A.; Rose, Robert B.

2010-01-01

368

X-ray diffraction investigation of 1-phenyl-3-isopropyl-5-(benzothiazol-2-yl)formazan  

SciTech Connect

The crystal structure of 1-phenyl-3-isopropyl-5-(benzothiazol-2-yl)formazan is investigated using X-ray diffraction. The compound crystallizes in the form of two crystallographically independent molecules (A and B) in identical conformations that are stabilized by intermolecular hydrogen bonds. The intermolecular hydrogen bonds N-H-N (N-N, 2.892 and 2.939 A) link molecules into AB dimers. Both molecules have a flattened structure, except for the isopropyl fragment. The bonds in the formazan chains are delocalized. Molecules A and B have close geometric characteristics.

Slepukhin, P. A. [Russian Academy of Sciences, Postovskii Institute of Organic Synthesis, Ural Division (Russian Federation)], E-mail: slepukhin@ios.uran.ru; Pervova, I. G.; Rezinskikh, Z. G. [Ural State Forestry Engineering University (Russian Federation); Lipunova, G. N. [Ural State Technical University (UPI) (Russian Federation); Gorbatenko, Yu. A.; Lipunov, I. N. [Ural State Forestry Engineering University (Russian Federation)

2008-01-15

369

Mössbauer, x-ray diffraction, and microscopy investigations of novel electrodeposited amorphous alloys  

NASA Astrophysics Data System (ADS)

New Sn-Fe binary, Sn-Co-Fe, and Sn-Ni-Fe ternary alloys were successfully deposited from an electrolyte based on sodium gluconate. X-ray diffraction and 57Fe and 119Sn Mössbauer results confirmed the existence of new metastable amorphous ferromagnetic and paramagnetic alloy phases within these deposits. It was possible to find deposition conditions at which the amorphous alloy phase was found to be a dominant phase for all the electrodeposits investigated. A nearly random distribution of alloying elements may be considered as a model of short-range order in the amorphous phases.

Kuzmann, E.; Sziráki, L.; Lak, G. B.; Stichleutner, S.; Havancsák, K.; Süvegh, K.; El-Sharif, M.; Chishholm, C. U.; Homonnay, Z.; Vértes, A.

2012-10-01

370

Quantitative X-ray diffraction analysis of oxides formed on superalloys  

NASA Technical Reports Server (NTRS)

Methods were developed for quantitative analysis by X-ray diffraction of the oxides Al2O3, NiO, Cr2O3, CoO, and CoCr2O4 within a standard deviation of about 10 percent of the weight fraction reported or within 1 percent absolute. These error limits assume that the sample oxides are well characterized and that the physiochemical structure of the oxides in the samples are identical with those in the synthesized standards. Results are given for the use of one of the techniques in the analysis of spalls from a series of oxidation tests of the cobalt base alloy WI-52.

Garlick, R. G.

1972-01-01

371

Development of an adaptable coherent x-ray diffraction microscope with the emphasis on imaging hydrated specimens  

SciTech Connect

This paper describes the development of a versatile coherent x-ray diffraction microscope capable of imaging biological specimens in solution. The microscope is a flexible platform accommodating various conditions, from low vacuum (10{sup ?2} Pa) to helium gas filled ambient pressure. This flexibility greatly expands the application area, from in situ materials science to biology systems in their native state, by significantly relaxing restrictions to the sample environment. The coherent diffraction microscope has been used successfully to image a yeast cell immersed in buffer solution. We believe that the design of this coherent diffraction microscope can be directly adapted to various platforms such as table top soft x-ray laser, synchrotron x-ray sources, and x-ray free electron laser with minor relevant adjustments.

Nam, Daewoong [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan) [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Park, Jaehyun; Shimada, Hiroki; Kim, Sangsoo; Kim, Sunam; Kohmura, Yoshiki; Ishikawa, Tetsuya; Song, Changyong [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan)] [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Gallagher-Jones, Marcus [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan) [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB (United Kingdom)

2013-11-15

372

Experimental novaculite deformation: interpretation of in-situ X-ray diffraction data using EPSC models  

NASA Astrophysics Data System (ADS)

The deformation behavior of fine-grained polycrystalline quartz (novaculite) was studied experimentally using in-situ X-ray diffraction and theoretically by elastic plastic self consistent modeling (EPSC). Previous experimental work has shown that different subpopulations of crystals experience different stress levels during high pressure deformation and reflection stresses may lead to poor approximations of macroscopic sample stresses, since in-situ diffraction data originates from grain scale phenomena rather than macroscopic sample properties [1]. In this context EPSC models have been utilized to interpret diffraction data, i.e., to independently derive the macroscopic sample load and to directly compare results with diffraction data. In our study a series of novaculite samples with 645 ± 50 wt ppm H2O was deformed in different regimes of disclocation-creep, at 2.5 GPa and up to ~1000 °C, in the D-DIA apparatus at the NSLS X17B2 beamline. In-situ synchrotron X-ray diffraction was used to monitor the sample stress state during controlled deformation and to observe the strain behavior of the individual lattice reflections of novaculite. Lattice strains were calculated from measured lattice spacings. The macroscopic sample strain was determined by sample radiographs. The strains provide information about how individual grains or grain populations react to stress depending on their orientation within the aggregate. We observe a reproducible elastic slope across the series of experiments and a temperature dependence of individual lattice strains and yield strength. In addition, EPSC models were calculated to theoretically determine macroscopic sample stresses and to match measured rheological sample properties with simulations. Depending on deformation conditions measured elastic lattice strains could be matched by activating basal and/or prism and/or pyramidal slip systems of the crystal structure. Here, we present EPSC models, compare macroscopic stresses obtained from in-situ deformation experiments and simulations, and discuss the practicability of using experimentally derived reflection stresses as proxy for the macroscopic sample load. [1] Burnley, P. C. and Zhang, D. (2008) Interpreting in situ x-ray diffraction data from high pressure deformation experiments using elastic-plastic self-consistent models: an example using quartz. J. Phys.: Condens. Matter, 20, 285201.

Thomas, S.; Willenweber, A.; Cline, C. J.; Sas, M.; Pape, D.; Erickson, B.; Bright, T.; Burnley, P. C.

2012-12-01

373

X-ray diffraction from flight muscle with a headless myosin mutation: implications for interpreting reflection patterns  

PubMed Central

Fruit fly (Drosophila melanogaster) is one of the most useful animal models to study the causes and effects of hereditary diseases because of its rich genetic resources. It is especially suitable for studying myopathies caused by myosin mutations, because specific mutations can be induced to the flight muscle-specific myosin isoform, while leaving other isoforms intact. Here we describe an X-ray-diffraction-based method to evaluate the structural effects of mutations in contractile proteins in Drosophila indirect flight muscle. Specifically, we describe the effect of the headless myosin mutation, Mhc10-Y97, in which the motor domain of the myosin head is deleted, on the X-ray diffraction pattern. The loss of general integrity of the filament lattice is evident from the pattern. A striking observation, however, is the prominent meridional reflection at d = 14.5 nm, a hallmark for the regularity of the myosin-containing thick filament. This reflection has long been considered to arise mainly from the myosin head, but taking the 6th actin layer line reflection as an internal control, the 14.5-nm reflection is even stronger than that of wild-type muscle. We confirmed these results via electron microscopy, wherein image analysis revealed structures with a similar periodicity. These observations have major implications on the interpretation of myosin-based reflections.

Iwamoto, Hiroyuki; Trombitas, Karoly; Yagi, Naoto; Suggs, Jennifer A.; Bernstein, Sanford I.

2014-01-01

374

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)

2012-10-15

375

Widths of the L x-ray lines of the rare-earth elements  

Microsoft Academic Search

An improved version of a single-crystal high-angle goniometer and a NaI scintillation detector were used to measure the widths of the L alpha1.2, L beta1-4, and L gamma1 x-ray lines of the elements 58<=Z<=74 and the widths of the less prominent lines L beta15, Ll, L eta, and Lgamma'1 of several elements in the same group. The x-ray spectrum of

S. I. Salem; P. L. Lee

1974-01-01

376

A suite of programs for calculating x-ray absorption, reflection, and diffraction performance for a variety of materials at arbitrary wavelengths  

SciTech Connect

One of the most useful characteristics of synchrotron radiation is the wide spectral distribution of the source. For applications involving tuned monochromatic beams it is often helpful to predict the x-ray optical characteristics of a sample or the beam line optics at a particular wavelength. In contrast to this desire stands the fact that tabulated values for the optical parameters of interest are generally available only at wavelengths corresponding to typical x-ray tube sources. We have developed a suite of FORTRAN programs which calculate photoabsorption cross sections and atomic scattering factors for materials of arbitrary, uniform composition or for arbitrary layered materials. Further, the suite includes programs for calculation of x-ray diffraction or reflection from such materials. These programs are of use for experimental planning, data analysis, and predictions of performance of beam line optical elements.

Brennan, S. (Stanford Synchrotron Radiation Laboratory, Stanford, California 94309 (United States)); Cowan, P.L. (National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States))

1992-01-01

377

Application of the X-ray fluorescence analysis and X-ray diffraction in geochemical studies of the Pleistocene tills from Holy Cross Mountains  

NASA Astrophysics Data System (ADS)

X-ray fluorescence analysis methods (wavelength dispersive X-ray fluorescence analysis (WDXRF) and total reflection X-ray fluorescence (TXRF)) and X-ray powder diffraction (XRPD) have been applied in complementary geochemical studies of the Pleistocene till samples. The XRPD technique gave information about the mineral composition of the analyzed samples while the WDXRF and TXRF studies allowed the fast elemental analysis. The till samples were collected from different regions of Holy Cross Mountains (located in central Poland) which are still not unambiguously described in the context of the geochemical studies of the Quaternary sediments. The analysis was concentrated on the geochemical composition of the till samples both for materials occurring on the surface (characterized by continuous weathering processes) and for samples taken from core borehole. The overriding purpose of these studies is determination of the local lithotype of the tills and its lithologic and petrographic diagnostic properties, including the chemical composition of clay and minerals found in the clay. In the presented work the experimental sets up, sample preparation procedure and measurements programme will be discussed in details. Finally, the elemental and mineral compositions will be presented for studied different groups of the samples.

Kubala-Kuku?, A.; Ludwikowska-K?dzia, M.; Bana?, D.; Braziewicz, J.; Majewska, U.; Pajek, M.; Wudarczyk-Mo?ko, J.

2013-12-01

378

Taking snapshots of photosynthetic water oxidation using femtosecond X-ray diffraction and spectroscopy  

NASA Astrophysics Data System (ADS)

The dioxygen we breathe is formed by light-induced oxidation of water in photosystem II. O2 formation takes place at a catalytic manganese cluster within milliseconds after the photosystem II reaction centre is excited by three single-turnover flashes. Here we present combined X-ray emission spectra and diffraction data of 2-flash (2F) and 3-flash (3F) photosystem II samples, and of a transient 3F’ state (250??s after the third flash), collected under functional conditions using an X-ray free electron laser. The spectra show that the initial O-O bond formation, coupled to Mn reduction, does not yet occur within 250??s after the third flash. Diffraction data of all states studied exhibit an anomalous scattering signal from Mn but show no significant structural changes at the present resolution of 4.5?Å. This study represents the initial frames in a molecular movie of the structural changes during the catalytic reaction in photosystem II.

Kern, Jan; Tran, Rosalie; Alonso-Mori, Roberto; Koroidov, Sergey; Echols, Nathaniel; Hattne, Johan; Ibrahim, Mohamed; Gul, Sheraz; Laksmono, Hartawan; Sierra, Raymond G.; Gildea, Richard J.; Han, Guangye; Hellmich, Julia; Lassalle-Kaiser, Benedikt; Chatterjee, Ruchira; Brewster, Aaron S.; Stan, Claudiu A.; Glöckner, Carina; Lampe, Alyssa; Difiore, Dörte; Milathianaki, Despina; Fry, Alan R.; Seibert, M. Marvin; Koglin, Jason E.; Gallo, Erik; Uhlig, Jens; Sokaras, Dimosthenis; Weng, Tsu-Chien; Zwart, Petrus H.; Skinner, David E.; Bogan, Michael J.; Messerschmidt, Marc; Glatzel, Pieter; Williams, Garth J.; Boutet, Sébastien; Adams, Paul D.; Zouni, Athina; Messinger, Johannes; Sauter, Nicholas K.; Bergmann, Uwe; Yano, Junko; Yachandra, Vittal K.

2014-07-01

379

Mesoscale morphology of airborne core-shell nanoparticle clusters: x-ray laser coherent diffraction imaging  

NASA Astrophysics Data System (ADS)

Unraveling the complex morphology of functional materials like core-shell nanoparticles and its evolution in different environments is still a challenge. Only recently has the single-particle coherent diffraction imaging (CDI), enabled by the ultrabright femtosecond free-electron laser pulses, provided breakthroughs in understanding mesoscopic morphology of nanoparticulate matter. Here, we report the first CDI results for Co@SiO2 core-shell nanoparticles randomly clustered in large airborne aggregates, obtained using the x-ray free-electron laser at the Linac Coherent Light Source. Our experimental results compare favourably with simulated diffraction patterns for clustered Co@SiO2 nanoparticles with ˜10 nm core diameter and ˜30 nm shell outer diameter, which confirms the ability to resolve the mesoscale morphology of complex metastable structures. The findings in this first morphological study of core-shell nanomaterials are a solid base for future time-resolved studies of dynamic phenomena in complex nanoparticulate matter using x-ray lasers.

Pedersoli, E.; Loh, N. D.; Capotondi, F.; Y Hampton, C.; Sierra, R. G.; Starodub, D.; Bostedt, C.; Bozek, J.; Nelson, A. J.; Aslam, M.; Li, S.; Dravid, V. P.; Martin, A. V.; Aquila, A.; Barty, A.; Fleckenstein, H.; Gumprecht, L.; Liang, M.; Nass, K.; Schulz, J.; White, T. A.; Coppola, N.; Bajt, S.; Barthelmess, M.; Graafsma, H.; Hirsemann, H.; Wunderer, C.; Epp, S. W.; Erk, B.; Rudek, B.; Rudenko, A.; Foucar, L.; Kassemeyer, S.; Lomb, L.; Rolles, D.; Shoeman, R. L.; Steinbrener, J.; Hartmann, R.; Hartmann, A.; Hauser, G.; Holl, P.; Kimmel, N.; Reich, C.; Soltau, H.; Weidenspointner, G.; Benner, W. H.; Farquar, G. R.; Hau-Riege, S. P.; Hunter, M. S.; Ekeberg, T.; Hantke, M.; Maia, F. R. N. C.; Tobias, H. J.; Marchesini, S.; Frank, M.; Strüder, L.; Schlichting, I.; Ullrich, J.; Chapman, H. N.; Bucksbaum, P. H.; Kiskinova, M.; Bogan, M. J.

2013-08-01

380

Analysis of urinary stone composition in Eastern India by X-ray diffraction crystallography  

PubMed Central

Background: Stones in the urinary system are common in our country. This study was done to assess the composition of the urinary stones in eastern part of India. Materials and Methods: A prospective study was done over a period of thirty months. A total of 90 stones were analyzed in this time period by using X-ray diffraction crystallography. Results: Of the 90 stones analyzed, 77 were renal stones, 12 were ureteric stones and one was a bladder stone. Six stones (all renal) did not have properties to be represented by X-ray diffraction crystallography. The overall prevalence of the oxalate containing stones was 85.7% with calcium oxalate monohydrate (COM) being the major constituent. Calcium oxalate dihydrate (COD) was the next most common constituent. Struvite stones constituted 9.5% of the stones analyzed. Pure calcium phosphate stones were found in 4.7% of the cases. Conclusion: Our study reveals that the stone composition in the eastern part of India is different from that in other parts of the country. We have a comparatively lower prevalence of oxalate stones while a higher prevalence of phosphate and struvite stones. PMID:25337533

Jindal, Tarun; Mandal, Soumendra Nath; Sonar, Pankaj; Kamal, Mir Reza; Ghosh, Nabankur; Karmakar, Dilip

2014-01-01

381

Dynamic in-situ X-ray Diffraction of Catalyzed Alanates  

SciTech Connect

The discovery that hydrogen can be reversible absorbed and desorbed from NaAlH{sub 4} by the addition of catalysts has created an entirely new prospect for lightweight hydrogen storage. NaAlH{sub 4} releases hydrogen through the following set of decomposition reactions: NaAlH{sub 4} {r_arrow} 1/3({alpha}-Na{sub 3}AlH{sub 6}) + 2/3Al + H{sub 2} {r_arrow} NaH + Al + 3/2H{sub 2}. These decomposition reactions as well as the reverse recombination reactions were directly observed using time-resolved in-situ x-ray powder diffraction. These measurements were performed under conditions similar to those found in PEM fuel cell operations (hydrogen absorption: 50--70 C, 10--15 bar Hz, hydrogen resorption: 80--110 C, 5--100 mbar H{sub 2}). Catalyst doping was found to dramatically improve kinetics under these conditions. In this study, the alanate was doped with a catalyst by dry ball-milling NaAlH{sub 4} with 2 mol.% solid TiCl{sub 3}. X-ray diffraction clearly showed that TiCl{sub 3} reacts with NaAlH{sub 4} to form NaCl during the doping process. Partial desorption of NaAlH{sub 4} was even observed to occur during the catalyst doping process.

Gross, K.J.; Sandrock, G.; Thomas, G.J.

2000-11-01

382

Development of an ultra-high resolution diffraction grating forsoft x-rays  

SciTech Connect

Resonant Inelastic X-ray Scattering (RIXS) is the one of themost powerful methods for investigation of the electronic structure ofmaterials, specifically of excitations in correlated electron systems.However the potential of the RIXS technique has not been fully exploitedbecause conventional grating spectrometers have not been capable ofachieving the extreme resolving powers that RIXS can utilize. State ofthe art spectrometers in the soft x-ray energy range achieve ~;0.25 eVresolution, compared to the energy scales of soft excitations andsuperconducting gap openings down to a few meV. Development ofdiffraction gratings with super high resolving power is necessary tosolve this problem. In this paper we study the possibilities offabrication of gratings of resolving power of up to 106 for the 0.5 1.5KeV energy range. This energy range corresponds to all or most of theuseful dipole transitions for elements of interest in most correlatedelectronic systems, i.e., oxygen K-edge of relevance to all oxides, thetransition metal L2,3 edges, and the M4,5 edges of the rare earths.Various approaches based on different kinds of diffraction gratings suchas deep-etched multilayer gratings, and multilayer coated echelettes arediscussed. We also present simulations of diffraction efficiency for suchgratings, and investigate the necessary fabricationtolerances.

Voronov, Dmitriy L.; Cambie, Rossana; Feshchenko, Ruslan M.; Gullikson, Eric M.; Padmore, Howard A.; Vinogradov, Alexander V.; Yashchuk, Valeriy V.

2007-08-21

383

X-Ray Diffraction Studies on Metal Deposition in Group D Streptococci  

PubMed Central

Tucker, Fayne L. (University of Southern California, Los Angeles), John W. Thomas, Milo D. Appleman, Stewart H. Goodman, and Jerry Donohue. X-ray diffraction studies on metal deposition in group D streptococci. J. Bacteriol. 92:1311–1314. 1966.—Streptococcus faecalis N83 and S. faecium K6A reduced several compounds of Group VI elements to the elemental form, but reduced none of several compounds tested containing elements of other groups. The elemental tellurium deposited by S. faecium K6A was in general of a larger particle size than that deposited by S. faecalis N83 as judged from X-ray diffraction analysis. The particle size of the deposited tellurium was correlated with the blackness of the precipitate produced by cells growing in the presence of tellurite. A black and gray variation was observed in S. faecium K6A which was considered to be due to particle size, the amount of tellurium present, and the location of the deposited tellurium. The gray color of S. faecium K6A was not due to the presence of any oxidized tellurium products. PMID:4958879

Tucker, Fayne L.; Thomas, John W.; Appleman, Milo D.; Goodman, Stewart H.; Donohue, Jerry

1966-01-01

384

Crystallization and preliminary X-ray diffraction of malate dehydrogenase from Plasmodium falciparum  

PubMed Central

The expression, purification, crystallization and preliminary X-ray diffraction characterization of malate dehydrogenase (MDH) from the malarial parasite Plasmodium falciparum (PfMDH) are reported. In order to gain a deeper understanding of the function and role of PfMDH, the protein was purified to homogeneity. The purified protein crystallized in space group P1, with unit-cell parameters a = 72, b = 157, c = 159?Å, ? = 105, ? = 101, ? = 95°. The resulting crystals diffracted to a maximal resolution of 2.24?Å and the structure has been solved by molecular replacement, with 16 monomers in the asymmetric unit. The 16 monomers are arranged into four independent tetramers, in agreement with previous reports demonstrating the tetrameric solution state of PfMDH. The X-­ray structure of PfMDH is expected to clarify the differences in catalysis by PfMDH compared with other MDH family members and to provide a basis for the structure-based design of specific PfMDH inhibitors as well as general MDH inhibitors. PMID:22684064

Wrenger, Carsten; Muller, Ingrid B.; Butzloff, Sabine; Jordanova, Rositsa; Lunev, Sergey; Groves, Matthew R.

2012-01-01

385

X-ray Diffraction Study of the Static Strength of tungsten to 69 Gpa  

SciTech Connect

The strength of tungsten was determined under static high pressures to 69 GPa using x-ray diffraction techniques in a diamond anvil cell. Analysis of x-ray diffraction peak broadening and measurement of peak shifts associated with lattice strains are two different methods for strength determination of materials under large nonhydrostatic compressions. Here these methods are directly compared under uniaxial compression in a diamond anvil cell. Our results demonstrate the consistency of the two approaches, and show that the yield strength of tungsten increases with compression, reaching a value of 5.3 GPa at the highest pressure. The obtained yield strength of tungsten is also compared with previous experimental data involving shock wave and static compression measurements, and with theoretical predictions. The high-pressure strength of tungsten is comparable to that of other dense metals such as Re and Mo, and ratio of yield strength to shear modulus is about 0.02 for all these materials between 20 and 70 GPa. The static strength of tungsten is much greater than values observed for W under shock loading but is very similar to values observed under quasi-isentropic loading.

He,D.; Duffy, T.

2006-01-01

386

X-ray diffraction study of the static strength of tungsten to 69 GPa  

SciTech Connect

The strength of tungsten was determined under static high pressures to 69 GPa using x-ray diffraction techniques in a diamond anvil cell. Analysis of x-ray diffraction peak broadening and measurement of peak shifts associated with lattice strains are two different methods for strength determination of materials under large nonhydrostatic compressions. Here these methods are directly compared under uniaxial compression in a diamond anvil cell. Our results demonstrate the consistency of the two approaches, and show that the yield strength of tungsten increases with compression, reaching a value of 5.3 GPa at the highest pressure. The obtained yield strength of tungsten is also compared with previous experimental data involving shock wave and static compression measurements, and with theoretical predictions. The high-pressure strength of tungsten is comparable to that of other dense metals such as Re and Mo, and ratio of yield strength to shear modulus is about 0.02 for all these materials between 20 and 70 GPa. The static strength of tungsten is much greater than values observed for W under shock loading but is very similar to values observed under quasi-isentropic loading.

He Duanwei; Duffy, Thomas S. [Department of Geosciences, Princeton University, Princeton, New Jersey 08544 (United States)

2006-04-01

387

Three dimensional x-ray diffraction microscope studies of bulk materials microstructure  

NASA Astrophysics Data System (ADS)

We have developed a synchrotron x-ray diffraction microscope at beamline 1-ID of the Advanced Photon Source capable of resolving Bragg reflections from the bulk in single crystals and coarse-grained polycrystalline materials. This three-dimensional x-ray diffraction microscope (3DXDM) can simultaneously map the spatial location, crystal orientation, and strain of ˜1000 grains in a polycrystal. Spatial accuracy is currently 30mum, with potential to reach a few mum. We can map the microstructure of 1 mm3 of material in 20 hours, or track the growth and change in orientation of a single grain in situ during annealing with a time resolution of 10 s. The measurements are non-destructive. This instrument has great potential to aid in investigations of basic problems of grain growth and deformation in materials. In this dissertation, we develop the mathematical and computational framework underlying the acquisition and analysis of 3DXDM data, and illustrate the power of the instrument by analysis of four types of data sets. Measurements of single crystal Si and Al serve to calibrate the instrument and demonstrate its resolving power. Measurements of a drawn-wire Au sample are used to develop the capability of resolving intragranular strain. An industrial purity Al sample is mapped ex-situ during a series of anneals. Finally, a single grain in an Al polycrystal is tracked in situ during annealing. A complete description of the instrument and data collection techniques is provided.

Hennessy, Daniel

388

Synchrotron Powder X-ray Diffraction Study of the Structure and Dehydration Behavior of Sepiolite  

SciTech Connect

Rietveld refinements using synchrotron powder X-ray diffraction data were used to study the crystal structure and dehydration behavior of sepiolite from Durango, Mexico. The room-temperature (RT) sepiolite structure in air compares well with previous models but reveals an additional zeolitic H{sub 2}O site. The RT structure under vacuum retained only {approx}1/8 of the zeolitic H{sub 2}O and the volume decreased by 1.3%. Real-time, temperature-resolved synchrotron powder X-ray diffraction data and Rietveld refinements were used to investigate the behavior of the sepiolite structure from 300 to 925 K. Rietveld refinements revealed that most of the zeolitic H{sub 2}O is lost by {approx}390 K, accompanied by a decrease in the a and c unit-cell parameters. Above {approx}600 K the sepiolite structure folds as one-half of the crystallographically bound H{sub 2}O is lost. Rietveld refinements of the 'anhydrous' sepiolite structure reveal that, in general, unit-cell parameters a and b and volume steadily decrease with increasing temperature; there is an obvious change in slope at {approx}820 K suggesting a phase transformation coinciding with the loss of the remaining bound H{sub 2}O molecule.

Post,J.; Bish, D.; Heaney, P.

2007-01-01

389

Photoionization and Photoemission by the Standing - Intensity of Dynamical X-Ray Diffraction.  

NASA Astrophysics Data System (ADS)

This thesis contains theoretical studies of nonrelativistic, inner-shell photoionization, and angle-resolved, photoelectron ejection by the standing-wave intensity of dynamical x -ray diffraction in the Bragg reflection geometry. These studies are carried out for two purposes: (1) to put the yield formulae of the X-Ray Standing Wave Technique (XSWT) in the differential form most appropriate for the application of photoelectron spectroscopy, and (2) to answer a lingering question on the adequacy of the dipole approximation for describing the photoeffect spectra of XSWT via investigating the effects of quadrupole retardation on the determination of the coherent fraction and the coherent position. In the dipole approximation, electron photoejection by the standing-wave intensity of XSWT has been found to differ from corresponding fluorescence and Auger emissions in that it proceeds at rate not proportional to the standing -wave intensity unless the dynamical diffraction field is in the sigma polarization geometry, or otherwise the XSWT experiment is performed at small Bragg angles or near-normal incidence conditions. It has also been found that the coherent position is by no means sensitive to effects owing to quadrupole retardation, whereas numerical results calculated for a Si adsorbate on a Ge substrate have exhibited changes exceeding 10% in the magnitude of the coherent fraction, but only for unfavorable experimental conditions. This observation has led to concluding the dipole approximation sound and accurate for most practical XSWT experiments.

Kayed, Mohammad Ahmad

390

Time-Resolved Soft X-ray Diffraction Reveals Transient Structural Distortions of Ternary Liquid Crystals  

PubMed Central

Home-based soft X-ray time-resolved scattering experiments with nanosecond time resolution (10 ns) and nanometer spatial resolution were carried out at a table top soft X-ray plasma source (2.2–5.2 nm). The investigated system was the lyotropic liquid crystal C16E7/paraffin/glycerol/formamide/IR 5. Usually, major changes in physical, chemical, and/or optical properties of the sample occur as a result of structural changes and shrinking morphology. Here, these effects occur as a consequence of the energy absorption in the sample upon optical laser excitation in the IR regime. The liquid crystal shows changes in the structural response within few hundred nanoseconds showing a time decay of 182 ns. A decrease of the Bragg peak diffracted intensity of 30% and a coherent macroscopic movement of the Bragg reflection are found as a response to the optical pump. The Bragg reflection movement is established to be isotropic and diffusion controlled (1 ?s). Structural processes are analyzed in the Patterson analysis framework of the time-varying diffraction peaks revealing that the inter-lamellar distance increases by 2.7 Å resulting in an elongation of the coherently expanding lamella crystallite. The present studies emphasize the possibility of applying TR-SXRD techniques for studying the mechanical dynamics of nanosystems. PMID:20087463

Quevedo, Wilson; Peth, Christian; Busse, Gerhard; Scholz, Mirko; Mann, Klaus; Techert, Simone

2009-01-01

391

Crystallization and X-ray diffraction of virus-like particles from a piscine betanodavirus.  

PubMed

Dragon grouper nervous necrosis virus (DGNNV), a member of the genus Betanodavirus, causes high mortality of larvae and juveniles of the grouper fish Epinephelus lanceolatus. Currently, there is no reported crystal structure of a fish nodavirus. The DGNNV virion capsid is derived from a single open reading frame that encodes a 338-amino-acid protein of approximately 37?kDa. The capsid protein of DGNNV was expressed to form virus-like particles (VLPs) in Escherichia coli. The VLP shape is T = 3 quasi-symmetric with a diameter of ?38?nm in cryo-electron microscopy images and is highly similar to the native virion. In this report, crystals of DGNNV VLPs were grown to a size of 0.27?mm within two weeks by the hanging-drop vapour-diffusion method at 283?K and diffracted X-rays to ?7.5?Å resolution. In-house X-ray diffraction data of the DGNNV VLP crystals showed that the crystals belonged to space group R32, with unit-cell parameters a = b = 353.00, c = 800.40?Å, ? = ? = 90, ? = 120°. 23?268 unique reflections were acquired with an overall Rmerge of 18.2% and a completeness of 93.2%. Self-rotation function maps confirmed the fivefold, threefold and twofold symmetries of the icosahedron of DGNNV VLPs. PMID:25084387

Luo, Yu-Chun; Wang, Chun-Hsiung; Wu, Yi-Min; Liu, Wangta; Lu, Ming-Wei; Lin, Chan-Shing

2014-08-01

392

Diffraction in forward direction of parametric X-ray radiation from relativistic particles of moderate energy  

NASA Astrophysics Data System (ADS)

The analytical expressions for the difference between the classical frequency of the parametric X-ray radiation (PXR) and the Bragg frequency in the PXR reflection are derived. The difference increases proportionally to the square of the angular distance to the PXR reflection center and also the Bragg frequency always exceeds the PXR one from the same system of crystallographic planes. A possibility of the existence of PXR diffraction from electrons of moderate energy to forward direction due to PXR peak broadening in a thin crystal and also in polycrystal or mosaic crystal is described. The experiment at accelerator for observation of PXR diffracted to forward direction in textured polycrystal or mosaic crystal is proposed. Application of PXR spectral peak broadening for measurement of thin crystal thickness, crystalline grains or domains size is proposed.

Shchagin, A. V.

2007-05-01

393

An x-ray diffraction method for semiquantitative mineralogical analysis of chilean nitrate ore  

USGS Publications Warehouse

Computer analysis of X-ray diffraction (XRD) data provides a simple method for determining the semiquantitative mineralogical composition of naturally occurring mixtures of saline minerals. The method herein described was adapted from a computer program for the study of mixtures of naturally occurring clay minerals. The program evaluates the relative intensities of selected diagnostic peaks for the minerals in a given mixture, and then calculates the relative concentrations of these minerals. The method requires precise calibration of XRD data for the minerals to be studied and selection of diffraction peaks that minimize inter-compound interferences. The calculated relative abundances are sufficiently accurate for direct comparison with bulk chemical analyses of naturally occurring saline mineral assemblages.

John, C.; George, J.; Ericksen, E.

1997-01-01

394

An X-ray diffraction method for semiquantitative mineralogical analysis of Chilean nitrate ore  

USGS Publications Warehouse

Computer analysis of X-ray diffraction (XRD) data provides a simple method for determining the semiquantitative mineralogical composition of naturally occurring mixtures of saline minerals. The method herein described was adapted from a computer program for the study of mixtures of naturally occurring clay minerals. The program evaluates the relative intensities of selected diagnostic peaks for the minerals in a given mixture, and then calculates the relative concentrations of these minerals. The method requires precise calibration of XRD data for the minerals to be studied and selection of diffraction peaks that minimize inter-compound interferences. The calculated relative abundances are sufficiently accurate for direct comparison with bulk chemical analyses of naturally occurring saline mineral assemblages.

Jackson, J. C.; Ericksent, G. E.

1997-01-01

395

Time-, frequency-, and wavevector-resolved x-ray diffraction from single molecules Kochise Bennett, Jason D. Biggs, Yu Zhang, Konstantin E. Dorfman, and Shaul Mukamel  

E-print Network

(2005); 10.1063/1.1844291 Time-resolved x-ray photoabsorption and diffraction on timescales from nsTime-, frequency-, and wavevector-resolved x-ray diffraction from single molecules Kochise Bennett soft X-ray scattering map of cysteine J. Chem. Phys. 138, 034306 (2013); 10.1063/1.4774059 Resonant

Mukamel, Shaul

396

OI Fluorescent Line Contamination in Soft X-Ray Diffuse Background Obtained with Suzaku/XIS  

E-print Network

The quantitative measurement of OVII line intensity is a powerful method for understanding the soft X-ray diffuse background. By systematically analyzing the OVII line intensity in 145 high-latitude Suzaku/XIS observations, the flux of OI fluorescent line in the XIS spectrum, contaminating the OVII line, is found to have an increasing trend with time especially after 2011. For these observations, the OVII line intensity would be overestimated unless taking into consideration the OI fluorescent line contamination. Since the OI line emission originates from solar X-rays, this increase suggests that incident solar X-rays at the OI fluorescence energy tend to be larger than the early phase of Suzaku observations (2005 - 2010).

Sekiya, Norio; Mitsuda, Kazuhisa; Takei, Yoh

2014-01-01

397

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

SciTech Connect

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)

2010-06-23

398

Development of a hard X-ray delay line for X-ray photon correlation spectroscopy and jitter-free pump-probe experiments at X-ray free-electron laser sources  

PubMed Central

A hard X-ray delay line capable of splitting and delaying single X-ray pulses has been developed with the aim of performing X-ray photon correlation spectroscopy (XPCS) and X-ray pump–probe experiments at hard X-ray free-electron laser sources. The performance of the device was tested with 8.39?keV synchrotron radiation. Time delays up to 2.95?ns have been demonstrated. The feasibility of the device for performing XPCS studies was tested by recording static speckle patterns. The achieved speckle contrast of 56% indicates the possibility of performing ultra-fast XPCS studies with the delay line. PMID:21525658

Roseker, Wojciech; Franz, Hermann; Schulte-Schrepping, Horst; Ehnes, Anita; Leupold, Olaf; Zontone, Federico; Lee, Sooheyong; Robert, Aymeric; Grubel, Gerhard

2011-01-01

399

X-ray absorption fine structure and x-ray diffraction studies of crystallographic grains in nanocrystalline FePd:Cu thin films  

NASA Astrophysics Data System (ADS)

FePd alloys have recently attracted considerable attention as candidates for ultrahigh density magnetic storage media. In this paper we investigate FePd thin alloy film with a copper admixture composed of nanometer-sized grains. [Fe(0.9 nm)/Pd(1.1 nm)/Cu(d nm)]×5 multilayers were prepared by thermal deposition at room temperature in UHV conditions on Si(100) substrates covered by 100 nm SiO2. The thickness of the copper layer has been changed from 0 to 0.4 nm. After deposition, the multilayers were rapidly annealed at 600 °C in a nitrogen atmosphere, which resulted in the creation of the FePd:Cu alloy. The structure of alloy films obtained this way was determined by x-ray diffraction (XRD), glancing angle x-ray diffraction, and x-ray absorption fine structure (EXAFS). The measurements clearly showed that the L10 FePd:Cu nanocrystalline phase has been formed during the annealing process for all investigated copper compositions. This paper concentrates on the crystallographic grain features of FePd:Cu alloys and illustrates that the EXAFS technique, supported by XRD measurements, can help to extend the information about grain size and grain shape of poorly crystallized materials. We show that, using an appropriate model of the FePd:Cu grains, the comparison of EXAFS and XRD results gives a reasonable agreement.

Krupinski, M.; Perzanowski, M.; Polit, A.; Zabila, Y.; Zarzycki, A.; Dobrowolska, A.; Marszalek, M.

2011-03-01

400

High energy x-ray diffraction/x-ray fluorescence spectroscopy for high-throughput analysis of composition spread thin films  

PubMed Central

High-throughput crystallography is an important tool in materials research, particularly for the rapid assessment of structure-property relationships. We present a technique for simultaneous acquisition of diffraction images and fluorescence spectra on a continuous composition spread thin film using a 60 keV x-ray source. Subsequent noninteractive data processing provides maps of the diffraction profiles, thin film fiber texture, and composition. Even for highly textured films, our diffraction technique provides detection of diffraction from each family of Bragg reflections, which affords direct comparison of the measured profiles with powder patterns of known phases. These techniques are important for high throughput combinatorial studies as they provide structure and composition maps which may be correlated with performance trends within an inorganic library. PMID:20059152

Gregoire, John M.; Dale, Darren; Kazimirov, Alexander; DiSalvo, Francis J.; van Dover, R. Bruce

2009-01-01

401

Enhancement of x-ray line emission from plasmas produced by short high-intensity laser double pulses  

E-print Network

Enhancement of x-ray line emission from plasmas produced by short high-intensity laser double laser-produced plasmas are bright ultrafast line x-ray sources potentially suitable for different onto a solid target into the x-ray emission is significantly enhanced when a laser prepulse precedes

Limpouch, Jiri

402

Feasibility of in-line instruments for high-resolution inelastic X-ray scattering.  

PubMed

Inelastic X-ray scattering instruments in operation at third-generation synchrotron radiation facilities are based on backreflections from perfect silicon crystals. This concept reaches back to the very beginnings of high-energy-resolution X-ray spectroscopy and has several advantages but also some inherent drawbacks. In this paper an alternate path is investigated using a different concept, the `M(4) instrument'. It consists of a combination of two in-line high-resolution monochromators, focusing mirrors and collimating mirrors. Design choices and performance estimates in comparison with existing conventional inelastic X-ray scattering instruments are presented. PMID:21335910

Sturhahn, W; Toellner, T S

2011-03-01

403

Beryllium window and acoustic delay line design for x-ray lithography beam lines at the University of Wisconsin Center for X-ray Lithography  

SciTech Connect

X-ray lithography systems require sample chambers that can perform exposures in helium gas at atmospheric pressure. The interface between the experimental chamber and the beamline is critical for x-ray lithography and the storage ring. It must allow a high x-ray flux throughput while providing a vacuum barrier so that helium gas does not leak into the beam line and the storage ring. The beam line must also be designed to have protection in the case that a window does fail in order to minimize adverse effects to the ring and other systems. The details of the design for the vacuum system used on beam lines for the Center for X-ray Lithography at the University of Wisconsin Synchrotron Radiation Center 1-GeV electron storage ring are reported. Curved beryllium windows with a 1{times}5-cm{sup 2} aperture and 13 {mu}m thick that have a leak rate less than 10{sup {minus}10} Torr l/s have been successfully used at the experimental chamber beam-line interface. This thin flat beryllium foil is mounted in a curved housing with a wire seal to minimize helium leakage. The window assembly is designed and has been tested to withstand substantial overpressure before failure. If the beryllium window does fail, the beamline has an acoustic delay line that is designed to delay the incoming shock wave of helium gas so that a fast valve at the end of the beam line will close and minimize leakage of helium into the storage ring. The acoustic delay line is designed with baffles to slow the shock front and a secondary thin window to protect against molecular diffusion into the storage ring. The acoustic delay line has been tested to determine the effect of baffle design on delay of the shock wave. A theoretical model that provides a good description of the acoustic delay has also been developed.

Brodsky, E.L. (Center for X-ray Lithography, University of Wisconsin, 3731 Schneider Drive, Stoughton, Wisconsin 53589 (United States)); Hamilton, W. (Nuclear Engineering and Engineering Physics, University of Wisconsin, 153 Engineering Research Building, Madison, Wisconsin 53705 (United States)); Wells, G.; Cerrina, F. (Center for X-ray Lithography, University of Wisconsin, 3731 Schneider Drive, Stoughton, Wisconsin 53589 (United States)); Corradini, M. (Nuclear Engineering and Engineering Physics, University of Wisconsin, 153 Engineering Research Building, Madison, Wisconsin 53705 (United States))

1992-01-01

404

ALS-II, a Potential Soft X-ray, Diffraction Limited Upgrade of the Advanced Light Source  

NASA Astrophysics Data System (ADS)

The Advanced Light Source (ALS) at Berkeley Lab has seen many upgrades over the years, keeping it one of the brightest sources for soft x-rays worldwide. Recent developments in magnet technology and lattice design appear to open the door for very large further increases in brightness [1], particularly by reducing the horizontal emittance, even within the space constraints of the existing tunnel. Initial studies for possible lattices will be presented that could approach the soft x-ray diffraction limit around 2 keV in both planes within the ALS footprint. Emerging scientific applications and experimental methods that would greatly benefit from ring based sources having much higher brightness and transverse coherence than present or near future storage ring facilities include nanometer imaging applications, X-ray correlation spectroscopy, diffraction microscopy, holography, ptychography, and resonant inelastic soft X-ray scattering at high resolution.

Tarawneh, H.; Steier, C.; Falcone, R.; Robin, D.; Nishimura, H.; Sun, C.; Wan, W.

2014-03-01

405

Macromolecular structures probed by combining single-shot free-electron laser diffraction with synchrotron coherent X-ray imaging.  

PubMed

Nanostructures formed from biological macromolecular complexes utilizing the self-assembly properties of smaller building blocks such as DNA and RNA hold promise for many applications, including sensing and drug delivery. New tools are required for their structural characterization. Intense, femtosecond X-ray pulses from X-ray free-electron lasers enable single-shot imaging allowing for instantaneous views of nanostructures at ambient temperatures. When combined judiciously with synchrotron X-rays of a complimentary nature, suitable for observing steady-state features, it is possible to perform ab initio structural investigation. Here we demonstrate a successful combination of femtosecond X-ray single-shot diffraction with an X-ray free-electron laser and coherent diffraction imaging with synchrotron X-rays to provide an insight into the nanostructure formation of a biological macromolecular complex: RNA interference microsponges. This newly introduced multimodal analysis with coherent X-rays can be applied to unveil nano-scale structural motifs from functional nanomaterials or biological nanocomplexes, without requiring a priori knowledge. PMID:24786694

Gallagher-Jones, Marcus; Bessho, Yoshitaka; Kim, Sunam; Park, Jaehyun; Kim, Sangsoo; Nam, Daewoong; Kim, Chan; Kim, Yoonhee; Noh, Do Young; Miyashita, Osamu; Tama, Florence; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Tono, Kensuke; Kohmura, Yoshiki; Yabashi, Makina; Hasnain, S Samar; Ishikawa, Tetsuya; Song, Changyong

2014-01-01

406

Macromolecular structures probed by combining single-shot free-electron laser diffraction with synchrotron coherent X-ray imaging  

NASA Astrophysics Data System (ADS)

Nanostructures formed from biological macromolecular complexes utilizing the self-assembly properties of smaller building blocks such as DNA and RNA hold promise for many applications, including sensing and drug delivery. New tools are required for their structural characterization. Intense, femtosecond X-ray pulses from X-ray free-electron lasers enable single-shot imaging allowing for instantaneous views of nanostructures at ambient temperatures. When combined judiciously with synchrotron X-rays of a complimentary nature, suitable for observing steady-state features, it is possible to perform ab initio structural investigation. Here we demonstrate a successful combination of femtosecond X-ray single-shot diffraction with an X-ray free-electron laser and coherent diffraction imaging with synchrotron X-rays to provide an insight into the nanostructure formation of a biological macromolecular complex: RNA interference microsponges. This newly introduced multimodal analysis with coherent X-rays can be applied to unveil nano-scale structural motifs from functional nanomaterials or biological nanocomplexes, without requiring a priori knowledge.

Gallagher-Jones, Marcus; Bessho, Yoshitaka; Kim, Sunam; Park, Jaehyun; Kim, Sangsoo; Nam, Daewoong; Kim, Chan; Kim, Yoonhee; Noh, Do Young; Miyashita, Osamu; Tama, Florence; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Tono, Kensuke; Kohmura, Yoshiki; Yabashi, Makina; Hasnain, S. Samar; Ishikawa, Tetsuya; Song, Changyong

2014-05-01

407

X-ray diffraction and absorption spectroscopic studies of copper mixed ligand complexes with aminophenol as one of the ligands  

NASA Astrophysics Data System (ADS)

X-ray diffraction (XRD) and X-ray absorption spectroscopic (XAS) studies have been conducted on two copper complexes, i.e., copper macrocyclic complex of succinic acid and ortho aminophenol (complex-1) and copper macrocyclic complex of pthalic acid and ortho aminophenol (complex-2). The diffraction pattern of the complexes have been recorded using Rigaku RINT-2000 X-ray diffractometer equipped with rotating anode X-ray tube operated at 40 kV and 100 mA. The X-ray absorption spectra of the complexes have been recorded at the K-edge of copper on Cauchois type bent crystal spectrograph having radius 0.4 m employing a mica crystal, oriented to reflect from (100) planes, for dispersion. The X-ray absorption near edge structure (XANES) parameters, viz., chemical shift, energy position of the principal absorption maximum and edge-width have been determined and discussed. From the extended X-ray absorption fine structure (EXAFS) data, the bond lengths have been calculated using three methods, namely, Levy's method, Lytle, Sayers and Stern's (LSS) method and Fourier transformation method. The results obtained have been compared with each other and discussed.

Mishra, A.; Jain, Garima; Patil, H.

2012-05-01

408

Single-shot x-ray differential phase contrast and diffraction imaging using two-dimensional transmission gratings  

PubMed Central

We describe an x-ray differential phase contrast imaging method based on two-dimensional transmission gratings that are directly resolved by an x-ray camera. X-ray refraction and diffraction in the sample lead to variations of the positions and amplitudes of the grating fringes on the camera. These effects can be quantified through spatial harmonic analysis. The use of 2D gratings allows differential phase contrast in several directions to be obtained from a single image. When compared to previous grating-based interferometry methods, this approach obviates the need for multiple exposures and separate measurements for different directions, and thereby accelerates imaging speed. PMID:20548343

Wen, Harold H.; Bennett, Eric E.; Kopace, Rael; Stein, Ashley F.; Pai, Vinay

2011-01-01

409

Strain and Texture in Al-Interconnect Wires Measured by X-Ray Microbeam Diffraction  

SciTech Connect

The local strain and texture in Al interconnect wires have been investigated using white and monochromatic x-ray microbeams on the MHATTCAT undulator beam line at the Advanced Photon Source. Intergrain and intragrain orientations were obtained with ~0.01 degree sensitivity using white beam measurements on wide Al pads (~100 Mu-m) and thin (2 Mu-m) Al wires. Orientation changes of up to 1 degree were found within individual grains of the (111) textured Al interconnects. Deviatoric strain measurements indicate small intragranular strain variations, but intergranular strain variations were found to be quite large.

Budai, J.D.; Chung, J.-S.; Ice, G.E.; Larson, B.C.; Lowe, W.P.; Tamura, N.; Tischler, J.Z.; Williams, E.L.; Yoon, M.

1999-04-05

410

Synchrotron Powder X-ray Diffraction Study of the Structure and Dehydration Behavior of Palygorskite  

SciTech Connect

Rietveld refinements using synchrotron powder X-ray diffraction data were used to study the crystal structure and dehydration behavior of pure monoclinic palygorskite samples from Korea and Alaska. The 300 and 100 K palygorskite structures in air compare well with previous models but provide additional details about zeolitic H2O sites and reveal that the Al atoms are ordered into the inner M2 octahedral sites and the Mg cations into the M3 sites at the edges of the tunnels. Real-time, temperature-resolved synchrotron powder X-ray diffraction data and Rietveld refinements were used to investigate the monoclinic palygorskite structure from 300 to 1400 K (in air). Rietveld refinements showed that most of the zeolitic H2O is lost by 425 K, accompanied by a decrease in the unit-cell volume of 1.3%, primarily owing to a decrease in the a unit-cell parameter and an increase in the ? angle. The structurally bound H2O is lost in two stages, at temperature intervals of 475-540 and 580-725 K. Above 825 K in air a portion of the Korean sample transformed to a folded structure; the Alaskan sample folded at 575 K under vacuum. A structure model was refined for the folded structure. At 1015 K for the sample heated in air, ?-quartz diffraction peaks appeared and increased in intensity as heating continued to the maximum temperature. Cristobalite formed above 1050 K, along with a small amount of clinoenstatite, and both phases persisted to the maximum temperature studied.

Post, J.; Heaney, P

2008-01-01

411

Capturing Transient Structures in the Elimination Reaction of Haloalkane in Solution by Transient X-ray Diffraction  

E-print Network

on beamline ID09B at the ESRF using a pump-probe scheme.1a,b Picosecond laser pulses (2 ps, 267 nm, 50 µ,2- diiodotetrafluoroethane (C2F4I2) in methanol solution using transient X-ray diffraction (TXD).1 The iodine eliminationJ/pulse) were used to initiate iodine elimination in C2F4I2, and delayed X-ray pulses (5 � 108 photons per pulse

Ihee, Hyotcherl

412

Influence of diffraction in crystals on the coherence properties of X-ray free-electron laser pulses  

SciTech Connect

The spatial and temporal evolution of the field of random X-ray femtosecond pulses and their coherent properties upon pulse propagation in free space and under dynamical diffraction in perfect crystals in the Bragg and Laue geometries has been analyzed on the basis of the formalism developed in statistical optics. Particular attention is paid to the influence of large pulse propagation distances, which are characteristic of lengthy channels of X-ray free-electron lasers.

Bushuev, V. A., E-mail: vabushuev@yandex.ru [Moscow State University (Russian Federation); Samoylova, L. [European XFEL GmbH (Germany)

2011-09-15

413

Soft X-Ray Microscopy at HZB: Zone Plate Development and Imaging Using the Third Order of Diffraction  

Microsoft Academic Search

The Helmholtz-Zentrum Berlin (HZB) operates a transmission x-ray microscope (TXM) in the soft x-ray photon energy range with an energy resolution up to E\\/DeltaE = 104 [1]. An approach to achieve ultrahigh spatial resolution with conventional, standard zone plate optics is to employ higher orders of diffraction of the zone plate objective [2]. In this paper, we demonstrate that 11-nm

S. Rehbein; P. Guttmann; S. Werner; G. Schneider

2011-01-01

414

Grazing incident asymmetric X-ray diffraction of ?-FeSi 2 layers, produced by ion beam synthesis  

Microsoft Academic Search

The crystal structure of ?-FeSi2 phase, prepared by ion beam synthesis (IBS) method, followed by rapid thermal annealing (RTA) is investigated by grazing incident asymmetric X-ray diffraction (GIAXRD). The X-ray spectra, obtained at different grazing angles, indicated that the ?-FeSi2 phase is formed in the whole implantation range. From the comparison of the reflections intensities ratios, it is found that

A. Atanassov; M. Baleva; V. Darakchieva; E. Goranova

2004-01-01

415

X-Ray Variability of the Narrow-Line Seyfert 1 Galaxy Markarian 478  

Microsoft Academic Search

We report the results of a timing analysis of X-ray observations of the bright narrow-line Seyfert 1 (NLS1) galaxy Mrk 478, obtained with the European Photon Imaging Camera (EPIC) on board XMM-Newton. The source was observed on four separate occasions between 2001 December and 2003 January, with the longest observation being ≈ 32 ks. X-ray light curves of Mrk 478

Adam R. Villarreal; T. E. Strohmayer

2006-01-01

416

Characterization of Delhi iron pillar rust by X-ray diffraction, Fourier transform infrared spectroscopy and Mössbauer spectroscopy  

Microsoft Academic Search

Rust samples obtained from the region just below the decorative bell capital of the Delhi iron pillar (DIP) have been analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Mössbauer spectroscopy. The identification of iron hydrogen phosphate hydrate in the crystalline form by XRD was unambiguous. Very weak diffraction from the oxyhydroxides\\/oxides of iron was observed indicating that

R Balasubramaniam; A. V Ramesh Kumar

2000-01-01

417

Relative X-ray line intensities and their application to a single standard procedure for quantitative X-ray microanalysis of bulk samples and thin films  

Microsoft Academic Search

X-ray spectra collected by an energy dispersive spectrometer on an electron microprobe analyzer were fitted to determine relative line intensities between elements for a wide range of atomic numbers. The relative line intensities within spectral series for K, L and M lines were also obtained. In the case of Kalpha lines an empirical formula is proposed for the prediction of

Michael S. Hatzistergos

2007-01-01

418

Combined Hydrodynamic and Diffraction Simulations of Femtosecond X-ray Scattering from Laser-Shocked Crystals  

NASA Astrophysics Data System (ADS)

We describe a simple hydrocode based on a two-step integration scheme that models the evolution of elastic and plastic strains in crystals subject to rapid laser-shock loading. By monitoring the elastic strains during plastic flow we track the rotation and spacing of lattice planes within the polycrystalline sample, and can thus predict the signal that would be produced by x-ray diffraction in a variety of experimental geometries. By employing a simple Taylor-Orowan dislocation model we simulate diffraction patterns in a Debye-Scherrer geometry to track the orthogonal strain states within a laser-shocked sample. The yielding rate is approximately matched to those observed in multi-million atom molecular dynamics (MD) simulations, allowing movies to be made of the diffraction images that would be seen in a real experimental geometry, and illustrating the pertinent experimental requirements, including target texture. Judicious choice of geometry allows clear demarcation of the initial elastic response of the target to be made from the subsequent plastic relaxation. We discuss the simulations in the context of the novel experimental capabilities that have recently become available with the advent of 4th generation light sources, which allow single-shot diffraction with sub-100-fsec resolution.

Wark, Justin S.; Higginbotham, Andrew; Milathianaki, Despina; Gleason, Arianna

2014-05-01

419

In situ time-resolved X-ray diffraction of tobermorite synthesis process under hydrothermal condition  

NASA Astrophysics Data System (ADS)

Hydrothermal synthesis process of tobermorite (5CaO.6SiO2.5H2O) has been investigated by in situ X-ray diffraction (XRD) using high-energy X-rays from a synchrotron radiation source in combination with a laboratory-made autoclave cell and a photon-counting pixel array detector. Three types of quartz sand having different particle size distributions were used. Not only the dissolution rate of quartz but also that of portlandite (Ca(OH)2) were largely affected by particle size distribution of quartz in starting mixtures. The effect of ?-Al2O3 on quartz dissolution and tobermorite formation was also investigated. In all cases, portlandite dissolved completely before the tobermorite formation, while a certain amount of quartz remained undissolved at the timing for tobermorite to start to be detected (denoted as T0). However, the composition (Ca/Si) of non-crystalline C-S-H at T0 was identical regardless of the quartz dissolution rate. Possible reaction mechanism for tobermorite formation has been discussed in terms of distribution of Ca/Si in non-crystalline C-S-H.

Kikuma, J.; Tsunashima, M.; Ishikawa, T.; Matsuno, S.; Ogawa, A.; Matsui, K.; Sato, M.

2011-03-01

420

Solution Synchrotron X-ray Diffraction Reveals Structural Details of Lipid Domains in Ternary Mixtures  

SciTech Connect

The influence of cholesterol on lipid bilayer structure is significant and the effect of cholesterol on lipid sorting and phase separation in lipid-raft-forming model membrane systems has been well investigated by microscopy methods on giant vesicles. An important consideration however is the influence of fluorescence illumination on the phase state of these lipids and this effect must be carefully minimized. In this paper, we show that synchrotron x-ray scattering on solution lipid mixtures is an effective alternative technique for the identification and characterization of the l o (liquid ordered) and l d (liquid disordered) phases. The high intensity of synchrotron x rays allows the observation of up to 5 orders of diffraction from the l o phase, whereas only two are clearly visible when the l d phase alone is present. This data can be collected in approximately 1 min/sample, allowing rapid generation of phase data. In this paper, we measure the lamellar spacing in both the liquid-ordered and liquid-disordered phases simultaneously, as a function of cholesterol concentration in two different ternary mixtures. We also observe evidence of a third gel-phaselike population at 10-12 mol % cholesterol and determine the thickness of the bilayer for this phase. Importantly we are able to look at phase coexistence in the membrane independent of photoeffects.

Yuan, J.; Kiss, A; Pramudya, Y; Nguyen, L; Hirst, L

2009-01-01

421

Surface x-ray diffraction of complex metal oxide surfaces and interfaces—a new era  

NASA Astrophysics Data System (ADS)

The availability of high-brilliance hard x-ray synchrotron radiation and the advent of novel photon counting area detectors have brought surface x-ray diffraction (SXRD) into a new era. It is now possible to record large numbers of structure factors with much improved reliability within reasonable beamtime durations. As a result, structural determination of the surfaces and interfaces of complex crystallographic systems and heterostructures has now become feasible, especially in conjunction with phase-retrieval methods. It is thereby hoped that detailed structural information will shed light on the unusual physical properties of these systems. Complex metal oxide systems investigated at the Materials Science beamline of the Swiss Light Source, including the surface of SrTiO3, the interface between LaAlO3 and SrTiO3, and the structure of YBa2Cu3O7 grown on NdGaO3, SrTiO3, and (LaSr)(AlTa)O3 will be presented as examples of what is now possible using SXRD.

Schlepü; tz, C. M.; Willmott, P. R.; Pauli, S. A.; Herger, R.; Martoccia, D.; Björck, M.; Kumah, D.; Clarke, R.; Yacoby, Y.

2009-01-01

422

X-ray diffraction analysis and source apportionment of Denver aerosol  

NASA Astrophysics Data System (ADS)

Continuous sampling of airborne particulate matter at Commerce City in northeast metropolitan Denver was carried out for 3-1/2 days in late January 1982.The resulting low-volume and dichotomous filter samples were analyzed by X-ray powder diffraction, X-ray transmission and optical polarizing microscopy. Major species identified in the coarse fraction include quartz, clays, two varieties of feldspar (one, potassiumrich) and muscovite. Carbonaceous matter occurs primarily in the fine fraction where 52.9 % was observed in the dichotomous sample. Artifact sodium nitrate was observed deep within the fine fraction filter substrate of the dichotomous sample. A least squares effective variance source apportionment was applied to both sample sets yielding the following mass-weighted average source contributions: soil material, 47 %; salt aerosol from street standing, 5 %; normal vehicular combustion, 4 %; and local diesel emissions, 20.5 %. Also observed was 2.6 % nitrate of undefined source and approximately 1 % receptor mass, each from adjacent flour mill activities and a nearby coal-fired power plant.

Davis, Briant L.

423

Upgrade of X-ray Magnetic Diffraction Experimental System and Its Application to Ferromagnetic Material  

SciTech Connect

We have performed X-ray magnetic diffraction (XMD) experiment of ferromagnets at the Photon Factory (PF) of the High Energy Accelerator Research Organization (KEK) in Tsukuba. In this study, we have upgraded the XMD experimental system in order to apply this method to as many samples as possible. Upgrade was made for (1) the X-ray counting system and related measurement program, (2) the electromagnet, and (3) the refrigerator. The performance of the system was enhanced so that (1) the counting rate capability was improved from 104cps to 105cps, (2) the maximum magnetic field was increased from 0.85T to 2.15T, and (3) the lowest sample temperature was reduced from 15K to 5K. The new system was applied to an orbital ordering compound of YTiO3, and we obtained spin magnetic form factor for the reflection plane (010) perpendicular to the b axis. The magnetic field of 2T was needed to saturate the magnetization of YTiO3 along the b axis. These are the first data with the magnetization of YTiO3 saturated along the b axis by the XMD.

Suzuki, Kosuke; Tsuji, Naruki; Akiyama, Hiromitu [Graduate School of Engineering, Gunma University, Tenjin-cho 1-5-1, Kiryu, Gunma 376-8515 (Japan); Ito, Masahisa; Kitani, Kensuke [Faculty of Engineering, Gunma University, Tenjin-cho 1-5-1, Kiryu, Gunma 376-8515 (Japan); Adachi, Hiromichi; Kawata, Hiroshi [Institute of Materials Structure Science, KEK, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan)

2007-01-19

424

Revealing the dynamic structure of complex solid catalysts using modulated excitation X-ray diffraction.  

PubMed

X-ray diffraction (XRD) is typically silent towards information on low loadings of precious metals on solid catalysts because of their finely dispersed nature. When combined with a concentration modulation approach, time-resolved high-energy XRD is able to provide the detailed redox dynamics of palladium nanoparticles with a diameter of 2?nm in 2?wt?% Pd/CZ (CZ = ceria-zirconia), which is a difficult sample for extended X-ray absorption fine structure (EXAFS) measurements because of the cerium component. The temporal evolution of the Pd(111) and Ce(111) reflections together with surface information from synchronous diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements reveals that Ce maintains Pd oxidized in the CO pulse, whereas reduction is detected at the beginning of the O2 pulse. Oxygen is likely transferred from Pd to Ce(3+) before the onset of Pd re-oxidation. In this context, adsorbed carbonates appear to be the rate-limiting species for re-oxidation. PMID:24903631

Ferri, Davide; Newton, Mark A; Di Michiel, Marco; Chiarello, Gian Luca; Yoon, Songhak; Lu, Ye; Andrieux, Jérôme

2014-08-18

425

X-ray diffraction, Raman, and photoacoustic studies of ZnTe nanocrystals  

NASA Astrophysics Data System (ADS)

Nanocrystalline ZnTe was prepared by mechanical alloying. X-ray diffraction (XRD), energy dispersive spectroscopy, Raman spectroscopy, and photoacoustic absorption spectroscopy techniques were used to study the structural, chemical, optical, and thermal properties of the as-milled powder. An annealing of the mechanical alloyed sample at 590 °C for 6 h was done to investigate the optical properties in a defect-free sample (close to bulk form). The main crystalline phase formed was the zinc-blende ZnTe, but residual trigonal tellurium and hexagonal ZnO phases were also observed for both as-milled and annealed samples. The structural parameters, phase fractions, average crystallite sizes, and microstrains of all crystalline phases were obtained from Rietveld analyses of the X-ray patterns. Raman results corroborate the XRD results, showing the longitudinal optical phonons of ZnTe (even at third order) and those modes of trigonal Te. Nonradiative surface recombination and thermal bending heat transfer mechanisms were proposed from photoacoustic analysis. An increase in effective thermal diffusivity coefficient was observed after annealing and the carrier diffusion coefficient, the surface recombination velocity, and the recombination time parameters remained the same.

Ersching, K.; Campos, C. E. M.; de Lima, J. C.; Grandi, T. A.; Souza, S. M.; da Silva, D. L.; Pizani, P. S.

2009-06-01

426

High-throughput synchrotron X-ray diffraction for combinatorial phase mapping.  

PubMed

Discovery of new materials drives the deployment of new technologies. Complex technological requirements demand precisely tailored material functionalities, and materials scientists are driven to search for these new materials in compositionally complex and often non-equilibrium spaces containing three, four or more elements. The phase behavior of these high-order composition spaces is mostly unknown and unexplored. High-throughput methods can offer strategies for efficiently searching complex and multi-dimensional material genomes for these much needed new materials and can also suggest a processing pathway for synthesizing them. However, high-throughput structural characterization is still relatively under-developed for rapid material discovery. Here, a synchrotron X-ray diffraction and fluorescence experiment for rapid measurement of both X-ray powder patterns and compositions for an array of samples in a material library is presented. The experiment is capable of measuring more than 5000 samples per day, as demonstrated by the acquisition of high-quality powder patterns in a bismuth-vanadium-iron oxide composition library. A detailed discussion of the scattering geometry and its ability to be tailored for different material systems is provided, with specific attention given to the characterization of fiber textured thin films. The described prototype facility is capable of meeting the structural characterization needs for the first generation of high-throughput material genomic searches. PMID:25343793

Gregoire, J M; Van Campen, D G; Miller, C E; Jones, R J R; Suram, S K; Mehta, A

2014-11-01

427

Diffraction-enhanced X-ray medical imaging at the ELETTRA synchrotron light source  

NASA Astrophysics Data System (ADS)

Conventional X-ray medical imaging makes use of the transmission properties of the sample. On the other hand, recently introduced phase-sensitive techniques take advantage of the phase shifts that occur when an electromagnetic wave encounters different refraction indices. Diffraction-Enhanced Imaging (DEI) is a phase-sensitive X-ray imaging technique based on the use of an analyzer placed between the sample and the detector. DEI performed at several synchrotron radiation facilities worldwide has proven outstanding image quality both in material science and medical imaging. At the medical imaging beamline SYRMEP under operation at the synchrotron radiation facility ELETTRA (Trieste, Italy), an analyzer system has been implemented to perform DEI. Experiments to evaluate the associated improvements in image quality were carried out on phantoms and biological samples and to prove that DEI is an appropriate tool for studying refraction and scattering properties. The results observed on the examples reported in this work suggest that t