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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

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...

5

In-line holography and coherent diffractive imaging with x-ray waveguides  

SciTech Connect

A Fresnel coherent diffraction imaging experiment with hard x rays is here presented, using two planar crossed waveguides as optical elements, leading to a virtual pointlike source. The coherent wave field obtained with this setup is used to illuminate a micrometric single object having the shape of a butterfly. A digital two-dimensional in-line holographic reconstruction of the unknown object at low resolution (200 nm) has been obtained directly via fast Fourier transform (FFT) of the raw data. The object and its twin image are well separated because suitable geometrical conditions are satisfied. A good estimate of the incident wave field phase has been extracted directly from the FFT of the raw data. A partial object reconstruction with 50 nm spatial resolution was achieved by fast iterative phase retrieval, the major limitation for a full reconstruction being the nonideal structure of the guided beam. The method offers a route for fast and reliable phase retrieval in x-ray coherent diffraction.

De Caro, L.; Giannini, C.; Guagliardi, A. [Istituto di Cristallografia, Consiglio Nazionale delle Ricerche (IC-CNR), via Amendola 122/O, I-70126 Bari (Italy); Pelliccia, D. [Dipartimento di Fisica, Universita di Roma 'La Sapienza' and INFN Sezione Roma 1, Roma (Italy); Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), via Cineto Romano 42, I-00156 Roma (Italy); Mocuta, C.; Metzger, T. H. [ESRF, Boite Postale 220, F-38043 Grenoble Cedex (France); Cedola, A.; Burkeeva, I.; Lagomarsino, S. [Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche (IFN-CNR), via Cineto Romano 42, I-00156 Roma (Italy)

2008-02-15

6

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

7

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...

8

Structural Transitions of NiMn Precipitation Nanostructures as Determined by X-ray Diffraction Line Broadening and M鰏sbauer Spectroscopy  

NASA Astrophysics Data System (ADS)

Structural transitions of nanometer-sized NiMn preprecipitates during isothermal aging of Fe-Ni-Mn alloys have been faintly indicated by the measurement of hardness and electrical resistivity changes. It is shown that a precise measurement of X-ray diffraction (XRD) line breadths in association with M鰏sbauer spectroscopy aims a better understanding of the structural transition of the precipitation nanostructures. Changes in the XRD line breadths clearly identified three stages corresponding to the stimulated clustering of solute elements, the formation of Guinier-Preston (GP) zones and subsequent transformation to the second-phase precipitates. Effective hardening takes place when preliminary solute clusters evolve to paramagnetic GP zones.

Movaghar Garabagh, Mohamad Reza; Hossein Nedjad, Syamak

2015-01-01

9

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

10

Diffraction enhanced x-ray imaging  

Microsoft Academic Search

Diffraction enhanced imaging is a new x-ray radiographic imaging modality using monochromatic x-rays from a synchrotron which produces images of thick absorbing objects that are almost completely free of scatter. They show dramatically improved contrast over standard imaging applied to the same phantom. The contrast is based not only on attenuation but also the refraction and diffraction properties of the

D. Chapman; W. Thomlinson; R. E. Johnston; D. Washburn; E. Pisano; N. Gm黵; Z. Zhong; R. Menk; F. Arfelli; D. Sayers

1997-01-01

11

X-ray Diffraction (XRD) 1.0 What is X-ray Diffraction  

E-print Network

X-ray Diffraction (XRD) 路 1.0 What is X-ray Diffraction 路 2.0 Basics of Crystallography 路 3.0 Production of X-rays 路 4.0 Applications of XRD 路 5.0 Instrumental Sources of Error 路 6.0 Conclusions #12 (Roentgenstrahlinterferenzen), commonly known as X-ray diffraction (XRD), and was direct evidence for the periodic atomic

Moeck, Peter

12

A comparison between different X-ray diffraction line broadening analysis methods for nanocrystalline ball-milled FCC powders  

NASA Astrophysics Data System (ADS)

The microstructural characteristics of aluminum, copper and nickel powders are investigated using different X-ray diffraction line broadening analysis approaches. Prior to analysis, the powders were ball-milled to produce a nanocrystalline structure with high density of probable types of lattice defects. A variety of methods, including Scherrer, Williamson-Smallman, Williamson-Hall, Warren-Averbach, modified Williamson-Hall, modified Warren-Averbach, Rietveld refinement and whole powder pattern modeling (WPPM) approaches are applied. In this way, microstructural characteristics such as crystallite size, microstrain, dislocation density, effective outer cut-off radius of dislocations and the probability of twining and stacking faults are calculated. On the other hand, the results of conventional and advanced line broadening analysis methods are compared. It is revealed that the density of linear and planar defects in the mechanically deformed aluminum powder is significantly smaller than that of copper and nickel, as well as the level of anisotropic strain broadening. Moreover, the WPPM procedure provided a better profile fitting with more accurate results.

Soleimanian, V.; Mojtahedi, M.

2015-02-01

13

X-Ray Diffractive Optics  

NASA Technical Reports Server (NTRS)

X-ray optics were fabricated with the capability of imaging solar x-ray sources with better than 0.1 arcsecond angular resolution, over an order of magnitude finer than is currently possible. Such images would provide a new window into the little-understood energy release and particle acceleration regions in solar flares. They constitute one of the most promising ways to probe these regions in the solar atmosphere with the sensitivity and angular resolution needed to better understand the physical processes involved. A circular slit structure with widths as fine as 0.85 micron etched in a silicon wafer 8 microns thick forms a phase zone plate version of a Fresnel lens capable of focusing approx. =.6 keV x-rays. The focal length of the 3-cm diameter lenses is 100 microns, and the angular resolution capability is better than 0.1 arcsecond. Such phase zone plates were fabricated in Goddard fs Detector Development Lab. (DDL) and tested at the Goddard 600-microns x-ray test facility. The test data verified that the desired angular resolution and throughput efficiency were achieved.

Dennis, Brian; Li, Mary; Skinner, Gerald

2013-01-01

14

X-Ray Diffraction Analysis Program  

NASA Technical Reports Server (NTRS)

SOPAD separates overlapping peaks and analyzes derivatives of X-ray diffraction data. SOPAD helps analyst get most information out of available diffraction data. SOPAD uses Marquardt-type nonlinear regression routine to refine initial estimates of individual peak positions, intensities, shapes, and half-widths.

Wiedemann, K. E.; Unnam, J.; Naidu, S. V. N.; Houska, C. R.

1986-01-01

15

X-Ray Diffraction Studies on Selected Bacterial Cell Walls  

PubMed Central

The cell walls of selected bacteria were studied by X-ray diffraction analysis to determine and characterize crystalline components. The walls were isolated by mechanical disruption and purified by enzymatic and washing procedures. The X-ray diffraction lines which appeared from the gram-positive cell walls were shown to be due to the constituent 搈ucopeptide fraction. No diffraction lines could be obtained from the gram-negative bacterium studied. The results show that crystallinity is associated with mucopeptide. Images PMID:4960150

Carito, Sebastian L.; Bazil, Stephen L.; DiGiacomo, Giulio

1967-01-01

16

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

17

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

18

Stress Analysis by X-Ray Diffraction  

Microsoft Academic Search

A mathematical analysis is presented for the problem of determining stresses in a metal by x-ray diffraction. The treatment is a general one, including as special cases the various methods for the determination of uniaxial stresses or the sum of two principal stresses in the plane of the metal surface. The analysis is extended to the problem of determining the

C. S. Barrett; M. Gensamer

1936-01-01

19

X-ray Diffraction Practicals 1 Graphics Programs  

E-print Network

X-ray Diffraction Practicals 1 Graphics Programs that will read SHELX or CIF files J. Reibenspies, N. Bhuvanesh ver 1.0.0 #12;X-ray Diffraction Practicals 2 Free software. Gretep : Reads SHELX files-ray Diffraction Practicals 3 Examples Gretep #12;X-ray Diffraction Practicals 4 Balls and Sticks example #12;X

Meagher, Mary

20

X-Ray Diffraction The X-Ray Diffraction facility is equipped with state-of-the-art  

E-print Network

.a.hriljac@bham.ac.uk Single Crystal X-Ray Instruments Rapid data collection and structure determination Low temperature structural characterisation Learn more For more details on single crystal X-Ray analysis contact Dr B Kariuki offering both single crystal and powder X-Ray diffraction. Powder X-Ray Diffraction High resolution data

Birmingham, University of

21

X-Ray Diffraction on NIF  

SciTech Connect

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

Eggert, J H; Wark, J

2012-02-15

22

In-line x-ray phase-contrast tomography and diffraction-contrast tomography study of the ferrite-cementite microstructure in steel  

NASA Astrophysics Data System (ADS)

This work presents the development of a non-destructive imaging technique for the investigation of the microstructure of cementite grains embedded in a ferrite matrix of medium-carbon steel. The measurements were carried out at the material science beamline of the European Synchrotron Radiation Facility (ESRF) ID11. It was shown that in-line X-ray phase-contrast tomography (PCT) can be used for the detection of cementite grains of several microns in size. X-ray PCT of the cementite structure can be achieved by either a `single distance' or a `multiple distance' acquisition protocol. The latter permits quantitative phase retrieval. A second imaging technique, X-ray diffraction-contrast tomography (DCT), was employed to obtain information about the shapes and crystallographic orientations of the distinct ferrite grains surrounding the cementite structures. The initial results demonstrate the feasibility of determining the geometry of the cementite grains after the austenite-ferrite phase-transformation in a non-destructive manner. The results obtained with PCT and DCT are verified with ex-situ optical microscopy studies of the same specimen.

Kostenko, Alexander; Sharma, Hemant; Dere, E. G鰖de; King, Andrew; Ludwig, Wolfgang; Van Oel, Wim; Offerman, S. Erik; Stallinga, Sjoerd; Vliet, Lucas J. van

2012-05-01

23

X-ray resonant powder diffraction  

NASA Astrophysics Data System (ADS)

X-ray resonant diffraction can be applied in structural chemistry studies on powder samples. It enables an important limitation of powder diffraction to be overcome. This limitation is related to the low ability of powder diffraction to differentiate elements with close atomic numbers when they occupy the same or close crystallographic sites (mixed occupancy case) and also to discriminate cations with different valence states in different sites. However the resonant effect usually has a second order influence on the measured intensity. As a consequence, the efficiency of this method directly implies the need for excellent quality data collection and has generally been better assessed on elements present in single phase powder samples. In recent years, instrumental developments have been made in synchrotron radiation facilities which allow easier use of resonant powder diffraction for site-specific contrast and valence i.e. oxidation state analyses. Moreover, resonant contrast diffraction tools also have been proposed for better visualization of the anomalous effect both in direct and reciprocal space by using differences between electron density maps or diffraction patterns. Finally the potentialities of this technique for de novo structure solution on macromolecular systems are mentioned.

Palancher, H.; Bos, S.; B閞ar, J. F.; Margiolaki, I.; Hodeau, J. L.

2012-06-01

24

X-ray line emission from Capella  

NASA Astrophysics Data System (ADS)

X-ray emission-line components from Mg, Si, S, and Fe are unambiguously detected from Capella with the solid-state spectrometer onboard the Einstein Observatory. The X-ray spectrum is inconsistent with an isothermal corona, and requires components between 6-million K and at least 24-million K for an adequate fit. An inhomogeneous corona in which the X-ray emitting plasma is confined to magnetically contained loops appears to be reconcilable with all of the experimental evidence.

Holt, S. S.; Boldt, E. A.; Serlemitsos, P. J.; White, N. E.; Becker, R. H.; Mushotzky, R. F.; Smith, B. W.

1979-11-01

25

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

SciTech Connect

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

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

1997-12-01

26

X-ray Diffraction Laboratory Department of Chemistry  

E-print Network

X-ray Diffraction Laboratory Department of Chemistry Texas A & M University College Station, Texas Phone : 979-845-9125 www.chem.tamu.edu/xray xray@tamu.edu X-rayDiffractionLaboratory Departmentof-ray diffraction analysis to the Texas A & M University system and to educate our students in the science

Meagher, Mary

27

Studies on X-ray diffraction microscopy  

NASA Astrophysics Data System (ADS)

This dissertation includes three main parts: studies on coherence requirements for the diffraction microscopy experiments, ice formation on frozen-hydrated sample during data collection, and centering of the diffraction data sets. These three subjects are all in support of our groups overall goal of high resolution 3D imaging of frozen hydrated eukaryotic cells via x-ray diffraction microscopy. X-ray diffraction microscopy requires coherent illumination. However, the actual degree of coherence at some beamlines has never been tested. In research on coherence, our first aim is to determine the transverse coherence width at the sample plane at BL 9.0.1 at the Advanced Light Source in Lawrence Berkeley National Laboratory. An analytical calculation of the coherence at the sample plane is presented. Experimental diffraction patterns of pinhole-pair samples were also taken at the beamline to determine the coherence. Due to the irregular shape of the pinholes and other optics complexity, it was very difficult to fit the data with known theoretical equations as it was traditionally done with 1D data. However, we found out that the auto-correlation function shows clearly three spots. Theoretical calculation have been carried out to show that the degree of coherence can be obtained from the intensities of the three spots. These results are compared with the results from the analytical calculation. We then perform a simulation, showing the required transverse coherence width for reconstructing samples with a given size. Ice accumulation has been a major problem in X-ray diffraction microscopy with frozen hydrated samples. Since the ice structure is different from point to point, we cannot subtract the scattering from ice, nor assume a completely "empty" region outside the finite support constraint area as required for reconstruction. Ice forms during the sample preparation and transfer. However, from the tests we did in September 2007, we found that the ice layer thickens significantly during the data collecting process. One of the tests we did was putting a dry room-temperature grid into the beam, cooling it down to liquid nitrogen temperature, and then collecting the diffraction pattern of it over time. This test showed that, after the cold grid remained in the chamber for a while, a ring could be observed in the diffraction pattern. The time necessary for this ring to be visible is highly dependent on the pressure and vacuum history of the chamber. We will discuss how the chamber pressure influences the ice accumulation rate, how an anti-contamination device can help to reduce the rate, and how this ring forms. The last part of the research is based on simulations and a real data set collected on beamline 9.0.1 at the ALS in Berkeley. In X-ray diffraction microscopy, one of the major challenges when processing the data is to accurately determine the true center of the recorded data; that is, the zero spatial frequency position. Simulations of reconstructing shifted data show that if the center of a 2D diffraction pattern is shifted by more than 3 pixels from its true center, the positivity constraint to the phase, which otherwise might be applied to improve the convergence of the reconstruction algorithm, cannot be imposed. Moreover, the phase unwrapping problem may appear during the reconstruction. These issues undermine the quality of the reconstruction of 2D data. Furthermore, the individual shift in each 2D pattern will lead to errors when assembling a 3D diffraction data cube, making the 3D reconstruction very difficult. We developed a method which uses power spectra of the partial diffraction pattern to pre-align the data. A reconstruction without severe phase unwrapping can then be obtained from the pre-aligned data. Next, the precise zero spatial frequency position can be found by examining the linear ramp present in the reconstructed phase. This method was applied to a freeze-dried yeast data set to show that this approach is effective with experimental data.

Miao, Huijie

28

Phase retrieval in x-ray coherent Fresnel projection-geometry diffraction  

SciTech Connect

Coherent x-ray diffraction experiments were performed in Fresnel regime, within a line-projection geometry. A planar x-ray waveguide was used to focus coherent cylindrical waves onto a 7.2 {mu}m Kevlar fiber, which acts as a phase object for hard x rays. The phase was retrieved, by using a Fourier-based iterative phasing algorithm, consistent with measured diffraction data and known constraints in real space, with a submicrometer spatial resolution.

De Caro, Liberato; Giannini, Cinzia; Cedola, Alessia; Pelliccia, Daniele; Lagomarsino, Stefano; Jark, Werner [Istituto di Cristallografia-Consiglio Nazionale delle Ricerche (IC-CNR), via Amendola 122/O, I-70126 Bari (Italy); Istituto di Fotonica e Nanotecnologie-Consiglio Nazionale delle Ricerche (IFN-CNR), via Cineto Romano 42, I-00156 Roma (Italy); Sincrotrone Trieste, S.S. 14 km 163.5, I-34012 Basovizza (TS) (Italy)

2007-01-22

29

The characterization of materials using x ray diffraction  

NASA Technical Reports Server (NTRS)

The objectives of this educational exercise are the following: to familiarize the student with x-ray techniques for diffraction pattern generation; to show the student how to utilize x-ray diffraction data for crystal structure determination; and to illustrate systematic and random errors associated with experimental data.

Sprecher, A. F., Jr.; West, Harvey A.; Fahmy, A. A.

1993-01-01

30

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

31

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

E-print Network

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

Cui, Yi

32

X-ray line emission from Capella  

NASA Astrophysics Data System (ADS)

X-ray emission line components from Mg, Si, S and Fe were unambiguously detected from Capella with the Solid-State Spectrometer onboard the Einstein Observatory. The X-ray spectrum is inconsistent with an isothermal corona, and requires components between 6,000,000 K and at least 24,000,000 K for an adequate fit. An inhomogeneous corona in which the X-ray emitting plasma is confined to magnetically-contained loops appears to be reconcilable with all of the experimental evidence.

Holt, S. S.; White, N. E.; Becker, R. H.; Boldt, E. A.; Mushotzky, R. F.; Serlemitsos, P. J.; Smith, B. W.

1979-06-01

33

Architectures and algorithms for x-ray diffraction imaging  

NASA Astrophysics Data System (ADS)

X-ray imaging is the predominant modality used in luggage inspection systems for explosives detection. Conventional or dual energy X-ray computed tomography imaging reconstructs the X-ray absorption characteristics of luggage contents at the different energies; however, material characterization based on absorption characteristics at these energies is often ambiguous. X-ray diffraction imaging (XDI) measures coherently scattered X-rays to construct diffraction profiles of materials that can provide additional molecular signature information to improve the identification of specific materials. In this paper, we present recent work on developing XDI algorithms for different architectures, which include limited angle tomography and the use of coded aperture masks. We study the potential benefits of fusion of dual energy CT information with X-ray diffraction imaging. We illustrate the performance of different approaches using Monte Carlo propagation simulations through 3-D media.

Chen, Ke; Casta耋n, David A.

2013-03-01

34

X-Ray Diffraction and Scattering Equipment and General Area Detector Diffraction System (GADDS)  

E-print Network

X-Ray Diffraction and Scattering Equipment and General Area Detector Diffraction System (GADDS) The materials characterization laboratory is equipped with state-of-the-art analytical x-ray diffraction, and structure refinement by the Rietveld method. Figure 1: State-of-the-art analytical x-ray diffraction

Gelfond, Michael

35

Mammography spectrum measurement using an x-ray diffraction device  

NASA Astrophysics Data System (ADS)

The use of a diffraction spectrometer developed by Deslattes for the determination of mammographic kV is extended to the measurement of accurate, relative x-ray spectra. Raw x-ray spectra (photon fluence versus energy) are determined by passing an x-ray beam through a bent quartz diffraction crystal, and the diffracted x-rays are detected by an x-ray intensifying screen coupled to a charge coupled device. Two nonlinear correction procedures, one operating on the energy axis and the other operating on the fluence axis, are described and performed on measured x-ray spectra. The corrected x-ray spectra are compared against tabulated x-ray spectra measured under nearly identical conditions. Results indicate that the current device is capable of producing accurate relative x-ray spectral measurements in the energy region from 12 keV to 40 keV, which represents most of the screen-film mammography energy range. Twelve keV is the low-energy cut-off, due to the design geometry of the device. The spectrometer was also used to determine the energy-dependent x-ray mass attenuation coefficients for aluminium, with excellent results in the 12-30 keV range. Additional utility of the device for accurately determining the attenuation characteristics of various normal and abnormal breast tissues and phantom substitutes is anticipated.

Boone, John M.; Yu, Tong; Seibert, Anthony

1998-09-01

36

Fractal analysis of powder X-ray diffraction patterns  

NASA Astrophysics Data System (ADS)

X-ray diffraction (XRD) patterns with broad background are commonly found in the characterization of materials with a certain degree of amorphicity, so the sharp intensity peaks associated with material phases are not well defined. This work used rescaled range (denoted by R/S) analysis, a method intended for fractal analysis of noisy signals, to characterize XRD patterns with broad background. It is found that XRD patterns with broad background are not random at all, but contain information on regularities expressed as autocorrelations of the intensity signal. Sol-gel alumina fired at different temperatures was used as an example to illustrate the applicability of the method. It is shown that fractal R/S analysis is able to locate angular regions that can be associated to ideal International Centre for Diffraction Data Powder Diffraction File (ICDD PDF) lines of diverse alumina phases.

Ortiz-Cruz, A.; Santolalla, C.; Moreno, E.; de los Reyes-Heredia, J. A.; Alvarez-Ramirez, J.

2012-02-01

37

Displaced Vertices from X-ray Lines  

E-print Network

We present a simple model of weak-scale thermal dark matter that gives rise to X-ray lines. Dark matter consists of two nearly degenerate states near the weak scale, which are populated thermally in the early universe via co-annihilation with slightly heavier states that are charged under the Standard Model. The X-ray line arises from the decay of the heavier dark matter component into the lighter one via a radiative dipole transition, at a rate that is slow compared to the age of the universe. The model predicts observable signatures at the LHC in the form of exotic events with missing energy and displaced leptons and jets. As an application, we show how this model can explain the recently observed 3.55 keV X-ray line.

Adam Falkowski; Yonit Hochberg; Joshua T. Ruderman

2014-09-09

38

1. Diffraction and the X-Ray Powder Diffractometer  

E-print Network

1. Diffraction and the X-Ray Powder Diffractometer 1.1 Diffraction 1.1.1 Introduction to Diffraction Materials are made of atoms. Knowledge of how atoms are arranged into crystal structures experimental techniques, but most of them involve diffraction. To date, most of our knowledge about the spatial

39

Diffractive-refractive optics: X-ray collimator  

Microsoft Academic Search

Diffractive-refractive optics are x-ray focusing monochromators based on the diffraction on profiled crystal surface. Diffraction on longitudinal parabolic groove machined in crystal surface forms a sagittaly focused synchrotron radiation beam. Such kind of monochromator may be realized as a crystal with parabolic hole, where the beam is diffracted on the inner wall of the hole. Two such asymmetrically cut crystals

Jarom韗 Hrd; Peter Oberta

2008-01-01

40

High-Resolution Detector For X-Ray Diffraction  

NASA Technical Reports Server (NTRS)

Proposed x-ray-sensitive imaging detector offers superior spatial resolution, counting-rate capacity, and dynamic range. Instrument based on laser-stimulated luminescence and reusable x-ray-sensitive film. Detector scans x-ray film line by line. Extracts latent image in film and simultaneously erases film for reuse. Used primarily for protein crystallography. Principle adapted to imaging detectors for electron microscopy and fluorescence spectroscopy and general use in astronomy, engineering, and medicine.

Carter, Daniel C.; Withrow, William K.; Pusey, Marc L.; Yost, Vaughn H.

1988-01-01

41

X-Ray Diffraction Studies of Copper Nanopowder  

E-print Network

Copper nanopowder preparation and its X-Ray diffraction studies are reported in this paper. Electrolytic cathode deposition method is simple and cheapest process for its preparation. Copper nanopowder has been prepared from aqueous copper sulphate solution. Wide range of experimental conditions has been adopted in this process and its X-Ray diffraction characterizations have been studied. The results confirming copper nanopowder with size below 30 nm. Uniformed size Copper nanopowder preparation, in normal room temperature is importance of this study.

T. Theivasanthi; M. Alagar

2010-03-31

42

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

43

Hard X-Ray Scanning Microscopy with Coherent Diffraction Contrast  

NASA Astrophysics Data System (ADS)

A hard x-ray scanning microscope based on nanofocusing refractive x-ray lenses is well suited for coherent x-ray diffraction imaging, in particular for scanning coherent diffraction microscopy also known as ptychography. Using this technique, the complex transmission function of the object can be obtained with a spatial resolution better than that given by the size of the nanofocus. In addition, the full complex wave field in the plane of the sample can be reconstructed simultaneously, allowing for a complete characterization of the illuminating nanobeam. This is illustrated by a ptychogram of a test structure recorded at 24.3 keV.

Schroer, C. G.; Schropp, A.; Boye, P.; Hoppe, R.; Patommel, J.; H鰊ig, S.; Samberg, D.; Stephan, S.; Sch鰀er, S.; Burghammer, M.; Wellenreuther, G.; Falkenberg, G.

2011-09-01

44

In-situ mechanical testing during X-ray diffraction  

SciTech Connect

Deforming metals during recording X-ray diffraction patterns is a useful tool to get a deeper understanding of the coupling between microstructure and mechanical behaviour. With the advances in flux, detector speed and focussing techniques at synchrotron facilities, in-situ mechanical testing is now possible during powder diffraction and Laue diffraction. The basic principle is explained together with illustrative examples.

Van Swygenhoven, Helena, E-mail: helena.vanswygenhoven@psi.ch; Van Petegem, Steven

2013-04-15

45

1. Diffraction and the X-Ray Powder Diffractometer . . . . . . . . 1 1.1 Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1  

E-print Network

Contents 1. Diffraction and the X-Ray Powder Diffractometer . . . . . . . . 1 1.1 Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 Introduction to Diffraction . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.2 Bragg Diffraction . . . . . . . . . . . . . . . . . 25 1.3.3 Monochromators, Filters, Mirrors

46

X-Ray Diffraction Microscopy of Magnetic Structures  

SciTech Connect

We report the first proof-of-principle experiment of iterative phase retrieval from magnetic x-ray diffraction. By using the resonant x-ray excitation process and coherent x-ray scattering, we show that linearly polarized soft x rays can be used to image both the amplitude and the phase of magnetic domain structures. We recovered the magnetic structure of an amorphous terbium-cobalt thin film with a spatial resolution of about 75 nm at the Co L{sub 3} edge at 778 eV. In comparison with soft x-ray microscopy images recorded with Fresnel zone plate optics at better than 25 nm spatial resolution, we find qualitative agreement in the observed magnetic structure.

Turner, J.; Lima, E.; Huang, X.; Krupin, O.; Seu, K.; Parks, D.; Kevan, S.; Kisslinger, K.; McNulty, I.; Gambino, R.; Mangin, S.; Roy, S. and Fischer, P.

2011-07-14

47

Potentialities of achromatized diffractive and diffractive-refractive X-ray focusing systems  

NASA Astrophysics Data System (ADS)

The potentialities of a single diffractive lens, a diffractive doublet-achromate, and a diffractive-refractive system for focusing of X-ray, undulator, and laser radiations are compared. The focusing quality was estimated from the rms radii of the X-ray scattering pattern and the radii of Airy disks in the diffraction-limited images of a point source.

Greisukh, G. I.; Ezhov, E. G.; Kazin, S. V.; Stepanov, S. A.

2012-03-01

48

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

49

Spectroscopic imaging, diffraction, and holography with x-ray photoemission  

SciTech Connect

X-ray probes are capable of determining the spatial structure of an atom in a specific chemical state, over length scales from about a micron all the way down to atomic resolution. Examples of these probes include photoemission microscopy, energy-dependent photoemission diffraction, photoelectron holography, and X-ray absorption microspectroscopy. Although the method of image formation, chemical-state sensitivity, and length scales can be very different, these X-ray techniques share a common goal of combining a capability for structure determination with chemical-state specificity. This workshop will address recent advances in holographic, diffraction, and direct imaging techniques using X-ray photoemission on both theoretical and experimental fronts. A particular emphasis will be on novel structure determinations with atomic resolution using photoelectrons.

Not Available

1992-02-01

50

High-throughput baggage scanning employing x-ray diffraction for accurate explosives detection  

NASA Astrophysics Data System (ADS)

X-ray systems dominate the installed base of airport baggage scanning systems for explosives detection. The majority are conveyer systems with projection line scanners. These systems can achieve a high throughput but exhibit a high false positive rate and require significant operator involvement. Systems employing computed tomography (CT) are currently being installed at a rapid rate. These can provide good discrimination of levels of xray absorption coefficient and can largely circumvent superimposition effects. Nonetheless CT measures only x-ray absorption coefficient per voxel which does not provide a means of specific material identification resulting in many false positives, and it is relatively straightforward to configure explosive materials so that they are undetectable by CT systems. Diffraction-based x-ray systems present a solution to this problem. They detect and measure atomic layer spacings in crystalline and microcrystalline materials with high sensitivity. This provides a means of specific material identification. The majority of explosive compounds are well crystallized solids at room temperature. X-ray diffraction systems using both conventional wavelength-dispersive diffraction and fixed-angle, multi-wavelength diffraction for improved throughput are described. Large-area, flat-panel x-ray detector technology coupled with an extended x-ray source will permit a full 3D volumetric x-ray diffraction scan of a bag in a single pass, (patent pending).

Green, Michael C.; Partain, Larry D.

2003-07-01

51

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

52

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

53

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

54

High Pressure桯igh Temperature, X-Ray Diffraction Apparatus  

Microsoft Academic Search

A tetrahedral-anvil press has been developed that permits x-ray diffraction powder measurements at pressures to 75 kb and temperatures to 1000癈. A counting technique, rather than photographic film, is used for x-ray detection. Sample tetrahedra of compressed LiH, boron, and boron-filled plastic are used in place of the pyrophyllite customarily used for this purpose. Two possible entrance pupils are used

J. Dean Barnett; H. Tracy Hall

1964-01-01

55

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPUSERFD form that can be accessed by the X-ray diffraction webpage. RESPONSIBILITY: The X-ray Diffraction and suggestions in a timely manner. MATERIALS: 路 Computer Database 路 Web interface #12;X-ray Diffraction

Meagher, Mary

56

High-resolution Hard-x-ray Microscopy using Second-order Zone-plate Diffraction  

SciTech Connect

Odd-order diffraction of zone plates (ZPs) is already used for x-ray microscopy but the potential offered by even-order diffraction must still be fully exploited. Width differences between lines and interline spaces transfer intensity from odd-order to even-order diffractions. Here we show that the resulting intense second-order diffraction provides a reasonable tradeoff between spatial resolution and intensity - and constitutes a viable strategy for x-ray microscopy to reach sub-20 nm resolution, in spite of the imperfections of high-aspect-ratio ZPs and of other difficulties.

J Yi; Y Chu; Y Chen; T Chen; Y Hwu; G Margaritondo

2011-12-31

57

Biological imaging by soft x-ray diffraction microscopy  

DOE PAGESBeta

We have used the method of x-ray diffraction microscopy to image the complex-valued exit wave of an intact and unstained yeast cell. The images of the freeze-dried cell, obtained by using 750-eV x-rays from different angular orientations, portray several of the cell's major internal components to 30-nm resolution. The good agreement among the independently recovered structures demonstrates the accuracy of the imaging technique. To obtain the best possible reconstructions, we have implemented procedures for handling noisy and incomplete diffraction data, and we propose a method for determining the reconstructed resolution. This work represents a previously uncharacterized application of x-ray diffraction microscopy to a specimen of this complexity and provides confidence in the feasibility of the ultimate goal of imaging biological specimens at 10-nm resolution in three dimensions.

Shapiro, D.; Thibault, P.; Beetz, T.; Elser, V.; Howells, M.; Jacobsen, C.; Kirz, J.; Lima, E.; Miao, H.; Neiman, A. M.; Sayre, D.

2005-10-25

58

X-Ray Diffraction of Myelin Membrane  

PubMed Central

The phase signs of the five main X-ray reflections from normal frog sciatic nerve have been determined as all positive using a technique of labeling with very small amounts of heavy metal. The changes in intensity of the individual reflections were studied as a function of uptake of metal label by the membrane. The possible localization of the metal label was decided from computer-analogue studies and from Patterson calculations. These phases are different from those determined by previous workers using techniques of trial of the best set of phases, or a step model, to give the best fit of the combined intensity data of normal and swollen myelin membranes. The electron density map has been calculated using eight reflections and their experimentally determined phases. The map shows an inner low electron density region which is different from that shown by earlier calculations. The center of the low electron density region shows a small region of increased electron density. However, without fixing absolute electron density levels in the map, it is not yet possible to allocate regions of low electron density to pure lipid or lipoprotein. The map shows the two sides of the membranes to be different in molecular structure without significant water spaces between the membranes. PMID:5414534

Akers, C. K.; Parsons, D. F.

1970-01-01

59

Dynamical diffraction imaging (topography) with X-ray synchrotron radiation  

NASA Technical Reports Server (NTRS)

By contrast to electron microscopy, which yields information on the location of features in small regions of materials, X-ray diffraction imaging can portray minute deviations from perfect crystalline order over larger areas. Synchrotron radiation-based X-ray optics technology uses a highly parallel incident beam to eliminate ambiguities in the interpretation of image details; scattering phenomena previously unobserved are now readily detected. Synchrotron diffraction imaging renders high-resolution, real-time, in situ observations of materials under pertinent environmental conditions possible.

Kuriyama, M.; Steiner, B. W.; Dobbyn, R. C.

1989-01-01

60

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

61

Hard x-ray nanobeam characterization by coherent diffraction microscopy  

SciTech Connect

We have carried out a ptychographic scanning coherent diffraction imaging experiment on a test object in order to characterize the hard x-ray nanobeam in a scanning x-ray microscope. In addition to a high resolution image of the test object, a detailed quantitative picture of the complex wave field in the nanofocus is obtained with high spatial resolution and dynamic range. Both are the result of high statistics due to the large number of diffraction patterns. The method yields a complete description of the focus, is robust against inaccuracies in sample positioning, and requires no particular shape or prior knowledge of the test object.

Schropp, A.; Boye, P.; Feldkamp, J. M.; Hoppe, R.; Patommel, J.; Samberg, D.; Stephan, S.; Schroer, C. G. [Institute of Structural Physics, Technische Universitaet Dresden, D-01062 Dresden (Germany); Giewekemeyer, K.; Wilke, R. N.; Salditt, T. [Institute of X-Ray Physics, Universitaet Goettingen, D-37077 Goettingen (Germany); Gulden, J.; Mancuso, A. P.; Vartanyants, I. A.; Weckert, E. [Deutsches Elektronen Synchrotron DESY, D-22607 Hamburg (Germany); Schoeder, S.; Burghammer, M. [European Synchrotron Radiation Facility (ESRF), BP 220, F-38043 Grenoble Cedex (France)

2010-03-01

62

Towards high-resolution ptychographic x-ray diffraction microscopy  

NASA Astrophysics Data System (ADS)

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 ?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; Zettsu, Nobuyuki; Kohmura, Yoshiki; Senba, Yasunori; Ohashi, Haruhiko; Yamauchi, Kazuto; Ishikawa, Tetsuya

2011-06-01

63

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

64

Diffraction and Imaging Study of Imperfections of Protein Crystals with Coherent X-rays  

NASA Technical Reports Server (NTRS)

High angular-resolution x-ray diffraction and phase contrast x-ray imaging were combined to study defects and perfection of protein crystals. Imperfections including line defects, inclusions and other microdefects were observed in the diffraction images of a uniformly grown lysozyme crystal. The observed line defects carry distinct dislocation features running approximately along the <110> growth front and have been found to originate mostly in a central growth area and occasionally in outer growth regions. 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 diffraction images. X-ray imaging and diffraction characterization of the quality of apoferritin crystals will also be discussed in the presentation.

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

2004-01-01

65

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

66

X-ray diffraction-based electronic structure calculations and experimental x-ray analysis for medical and materials applications  

Microsoft Academic Search

This thesis includes x-ray experiments for medical and materials applications and the use of x-ray diffraction data in a first-principles study of electronic structures and hyperfine properties of chemical and biological systems. Polycapillary focusing lenses were used to collect divergent x rays emitted from conventional x-ray tubes and redirect them to form an intense focused beam. These lenses are routinely

Dip Narayan Mahato

2009-01-01

67

Laboratory Manual 1.0.6 What is X-ray Diffraction?  

E-print Network

Laboratory Manual 1.0.6 Background What is X-ray Diffraction? X-rays scatter off of electrons, in a process of absorption and re-admission. Diffraction is the accumulative result of the x-ray scattering-rays in 1895 enabled scientists to probe crystalline structure at the atomic level. X-ray diffraction has been

Meagher, Mary

68

Laboratory Manual 1.0.7 What is X-ray Diffraction?  

E-print Network

Laboratory Manual 1.0.7 Background What is X-ray Diffraction? X-rays scatter off of electrons, in a process of absorption and re-admission. Diffraction is the accumulative result of the x-ray scattering-rays in 1895 enabled scientists to probe crystalline structure at the atomic level. X-ray diffraction has been

Meagher, Mary

69

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

70

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

71

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

72

X-ray diffraction characterization of thin superconductive films  

Microsoft Academic Search

The physical and mechanical properties of thin films are often different from the properties of bulk material and are dictated by the film\\/substrate orientation relationship, crystal anisotropy and crystalgraphic texture of the film. X-ray diffraction texture analysis provides information about preferential film growth and can be used for optimization of deposition parameters and prediction of properties of thin films. An

K. J. Kozaczek; T. R. Watkins; W. B. Carter

1995-01-01

73

X-ray diffraction study of pure plutonium under pressure  

Microsoft Academic Search

Atomic volume and bulk modulus represent basic cohesion properties of a material and are therefore linked to many other physical properties. However, large discrepancies are found in the literature regarding values for the bulk modulus of pure plutonium (?-phase). New X-ray diffraction measurements of plutonium in diamond anvil cell are presented and the isothermal bulk modulus is extracted.

Ph. Faure; C. Genestier

2009-01-01

74

X-Ray Diffraction Simulation Using Laser Pointers and Printers.  

ERIC Educational Resources Information Center

Uses a laser pointer to demonstrate the analogy between optical and X-ray diffraction and a laser printer with 600 or 1200 dot resolution to create and modify arrays, print them on transparencies, and illuminate them with laser pointers. Includes 14 references. (Author/YDS)

Johnson, Neil E.

2001-01-01

75

Single photon energy dispersive x-ray diffraction  

SciTech Connect

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.

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

2014-03-15

76

Single photon energy dispersive x-ray diffraction  

NASA Astrophysics Data System (ADS)

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.

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

77

Computing Composition/Depth Profiles From X-Ray Diffraction  

NASA Technical Reports Server (NTRS)

Diffraction-intensity bands deconvolved relatively quickly. TIBAC constructs composition/depth profiles from X-ray diffraction-intensity bands. Intensity band extremely sensitive to shape of composition/depth profile. TIBAC incorporates straightforward transformation of intensity band that retains accuracy of earlier simulation models, but is several orders of magnitude faster in total computational time. TIBAC written in FORTRAN 77 for batch execution.

Wiedemann, K. E.; Unnam, J.

1986-01-01

78

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

79

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

80

Resonance energy shifts during nuclear Bragg diffraction of x rays  

NASA Astrophysics Data System (ADS)

We have observed dramatic changes in the time distribution of synchrotron x rays resonantly scattered from 57Fe 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.

1989-10-01

81

Diffraction enhanced X-ray imaging of mammals crystalline lens  

NASA Astrophysics Data System (ADS)

Crystalline lenses are transparent biological materials where the organization of the lens fibers can also be affected by changes at molecular level, and therefore the structure and morphology of the tissue can be correlated to the loss of transparency of the lens. In this work, internal structure of mammal lenses regarding the long-range ordering of the fibers are investigated by diffraction enhanced X-ray imaging (DEI) radiography. Moreover, DEI and absorption X-ray synchrotron radiographs for healthy and cataractous crystalline lenses are compared. Significant differences in healthy and cataractous crystalline lenses are observed.

Antunes, A.; H鰊nicke, M. G.; Safatle, A. M. V.; Cusatis, C.; Moraes Barros, P. S.; Morelh鉶, S. L.

2005-08-01

82

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.

83

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

84

Discovery and development of x-ray diffraction  

NASA Astrophysics Data System (ADS)

In 1912 Max Laue at University of Munich reasoned x-rays to be short wavelength electromagnetic waves and figured interference would occur when scattered off crystals. Arnold Sommerfeld, W. Wien, Ewald and others, raised objections to Laue's idea, but soon Walter Friedrich succeeded in recording x-ray interference patterns off copper sulfate crystals. But the Laue-Ewald's 3-dimensional formula predicted excess spots. Fewer spots were observed. William Lawrence Bragg then 22 year old studying at Cambridge University heard the Munich results from father William Henry Brag, physics professor at Univ of Leeds. Lawrence figured the spots are 2-d interference of x-ray wavelets reflecting off successive atomic planes and derived a simple eponymous equation, the Bragg equation d*sin(theta)= n*lamda. 1913 onward the Braggs dominated the crystallography. Max Laue was awarded the physics Nobel in 1914 and the Braggs shared the same in 1915. Starting with Rontgen's first ever prize in 1901, the importance of x-ray techniques is evident from the four out of a total 16 physics Nobels between 1901-1917. We will outline the historical back ground and importance of x-ray diffraction giving rise to techniques that even in 2013, remain work horses in laboratories all over the globe.

Jeong, Yeuncheol; Yin, Ming; Datta, Timir

2013-03-01

85

Ultrafast time resolved x-ray diffraction, extended x-ray absorption fine structure and x-ray absorption near edge structure  

NASA Astrophysics Data System (ADS)

Ultrafast time resolved x-ray absorption and x-ray diffraction have made it possible to measure, in real time, transient phenomena structures and processes induced by optical femtosecond pulses. To illustrate the power of these experimental methods, we present several representative examples from the literature. (I) Time resolved measurements of photon/electron coupling, electron/phonon interaction, pressure wave formation, melting and recrystallization by means of time resolved x-ray diffraction. (II) Ultrafast x-ray absorption, EXAFS, for the direct measurement of the structures and their kinetics, evolved during electron transfer within molecules in liquid phase. (III) XANES experiments that measure directly pathway for the population of high spin states and the study of the operating mechanism of dye activated TiO2 solar cell devices. The construction and use of novel polycapillary x-ray lenses that focus and collimate hard x-rays efficiently are described.

Oguz Er, Ali; Chen, Jie; Rentzepis, Peter M.

2012-08-01

86

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; Thiaudi鑢e, D; Vicat, J; Zielinski, P; Kahn, R

2000-07-01

87

Liquid detection trial with x-ray diffraction  

NASA Astrophysics Data System (ADS)

SALOME (an acronym for Small Angle Lab Operation Measuring Equipment) is a versatile, energy-dispersive x-ray diffraction imaging (XDi) test-bed facility commissioned and supported by the Transportation Security Laboratory, Atlantic City, USA. In work presented here, the Inverse Fan-beam (IFB) topology has been realized on SALOME and used to investigate the liquids identification capability of x-ray diffraction (XRD). Liquids were investigated from four classes of materials of relevance to security screening of aircraft passenger luggage; namely: dilute aqueous liquids; concentrated aqueous liquids; hydrocarbon fuels; and oxidizers. A set of features associated with the Molecular Interference Function (MIF) were used to classify the liquids. Within the limited scope of this investigation, XRD proved to have excellent capability for discriminating liquids from one another; in particular, for isolating the threat materials without raising false alarms from either household or innocuous substances. Consequences for XRD-based screening of air passenger luggage are summarized.

Harding, G.; Fleckenstein, H.; Olesinski, S.; Zienert, G.

2010-08-01

88

X-ray Diffraction Topographic Studies of Dislocations in Natural Large Ice Single Crystals  

Microsoft Academic Search

The method of X-ray diffraction topography was adopted to reveal the dislocation structure in natural, large ice single crystals which has been hitherto used for the extensive experiments of plastic deformation. The topographs show clear images of curved and straight dislocation lines lying on the basal planes of the crystal. Dislocation density is in the order of 104 cm-2 and

Akeharu Fukuda; Akira Higashi

1969-01-01

89

Image Intensification of X-Ray Diffraction Patterns from Protein Molecules  

Microsoft Academic Search

An image intensifier film system has been used to obtain X-ray diffraction patterns suitable for quantitative measurements of protein structure. Relevant image tube characteristics have been measured, as have the corresponding TV vidicon parameters for extension of the systems to on-line digital recording and analysis.

J. R. Milch; Geo. T. Reynolds; T. C. Minor

1975-01-01

90

High pressure X-ray diffraction study of tungsten disulfide  

Microsoft Academic Search

Synchrotron X-ray diffraction was used in conjunction with a diamond anvil cell to investigate the properties of tungsten disulfide (WS2) to 25.5GPa at room temperature. No pressure medium was used to generate hydrostatic pressure. No phase transformation was observed in the pressure range studied. By fitting the pressure-volume data to the third-order Birch-Murnaghan equation of state, the bulk modulus was

Emre Selvi; Yanzhang Ma; Resul Aksoy; Atila Ertas; Allen White

2006-01-01

91

Coherent X-ray diffraction from collagenous soft tissues  

PubMed Central

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 6070 nm. We present simulations of the contrast mechanism in collagen based on atomic force microscope images of the samples. Simulations confirmed the 憇peckled 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. PMID:19706395

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

2009-01-01

92

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

93

First x-ray diffraction photograph of a shaped charge jet  

Microsoft Academic Search

A flash x-ray diffraction system has been constructed which permits x-ray diffraction patterns to be recorded from shaped charge jets. The system was tested by recording an x-ray diffraction pattern from an aluminum jet 80 ?sec after charge detonation with a single pulse of 70 nsec duration. This result represents the first successful recording of an x-ray diffraction pattern from

Robert E. Green

1975-01-01

94

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

95

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

96

X-ray diffraction of strained muscle fibers in rigor.  

PubMed Central

The effect of strain on the equatorial x-ray diffraction pattern of glycerinated rabbit psoas fibers was studied in the rigor (ATP free) state. Strains between 30 and 100 A per half sarcomere, measured directly by laser diffraction, did not change the intensity ratio, (10)/ . (11). Because the intensity ratio depends on the distribution of mass within the myofilament lattice, the negative result indicates that strain does not change the angle of attachment of the subfragment 1 (S1) moiety of the myosin molecule to the actin filament. The effect of strain on the ordering of the actin filaments also was considered and judged to be negligible. Images PMID:6946493

Naylor, G R; Podolsky, R J

1981-01-01

97

Diffraction effects on angular response of X-ray collimators  

NASA Technical Reports Server (NTRS)

Angular responses have been measured for X-ray collimators with half-widths ranging from minutes of arc down to 10 arcsec. In the seconds-of-arc range, diffraction peaks at off-axis angles can masquerade as side lobes of the collimator angular response. Measurements and qualitative physical arguments lead to a rule of thumb for collimator design; namely, the angle of first minimum in the Fraunhofer single-slit diffraction pattern should be less than one-fourth of the collimator geometrical full-width at half-maximum intensity.

Blake, R. L.; Barrus, D. M.; Fenimore, E.

1976-01-01

98

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPSAXSLA Rev;Operation of Siemens D-500 X-ray Diffractometers Approved :JHR 1/8/2009 路 The X-ray Diffraction Laboratory applicable training assignments in accordance the EHSO guidelines. #12;Xray Diffraction Laboratory: Texas

Meagher, Mary

99

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPABSSTR. BACKGROUND AND PRECAUTIONS 1. Single-Crystal X-ray diffraction is a method by which investigators can pertaining to radiation producing devices. 路 The X-ray Diffraction Laboratory manager will monitor the proper

Meagher, Mary

100

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPPOWGAD AND PRECAUTIONS 1. Powder X-ray diffraction is a method by which investigators can identify the materials) guidelines pertaining to radiation producing devices. 路 The X-ray Diffraction Laboratory manager will monitor

Meagher, Mary

101

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPALIGNA data possible. BACKGROUND AND PRECAUTIONS 1. Single-Crystal X-ray diffraction is a method by which pertaining to radiation producing devices. 路 The X-ray Diffraction Laboratory manager will monitor the proper

Meagher, Mary

102

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPDATGAD. BACKGROUND AND PRECAUTIONS 1. Single-Crystal X-ray diffraction is a method by which investigators can pertaining to radiation producing devices. 路 The X-ray Diffraction Laboratory manager will monitor the proper

Meagher, Mary

103

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPALIGNS data possible. BACKGROUND AND PRECAUTIONS 1. Single-Crystal X-ray diffraction is a method by which pertaining to radiation producing devices. 路 The X-ray Diffraction Laboratory manager will monitor the proper

Meagher, Mary

104

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPDATSM1. BACKGROUND AND PRECAUTIONS 1. Single-Crystal X-ray diffraction is a method by which investigators can pertaining to radiation producing devices. 路 The X-ray Diffraction Laboratory manager will monitor the proper

Meagher, Mary

105

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPDATSMA. BACKGROUND AND PRECAUTIONS 1. Single-Crystal X-ray diffraction is a method by which investigators can pertaining to radiation producing devices. 路 The X-ray Diffraction Laboratory manager will monitor the proper

Meagher, Mary

106

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPDATAP1. BACKGROUND AND PRECAUTIONS 1. Single-Crystal X-ray diffraction is a method by which investigators can pertaining to radiation producing devices. 路 The X-ray Diffraction Laboratory manager will monitor the proper

Meagher, Mary

107

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPDATAP2. BACKGROUND AND PRECAUTIONS 1. Single-Crystal X-ray diffraction is a method by which investigators can pertaining to radiation producing devices. 路 The X-ray Diffraction Laboratory manager will monitor the proper

Meagher, Mary

108

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPLABSEC that will prevent unwanted access to X-ray diffraction laboratory by unauthorized users. POLICY: All entrance to the X-ray Diffraction Laboratory is controlled by magnetic ID cards issued by Texas A & M University

Meagher, Mary

109

Diffraction enhanced kinetic depth X-ray imaging  

NASA Astrophysics Data System (ADS)

An increasing number of fields would benefit from a single analytical probe that can characterise bulk objects that vary in morphology and/or material composition. These fields include security screening, medicine and material science. In this study the X-ray region is shown to be an effective probe for the characterisation of materials. The most prominent analytical techniques that utilise X-radiation are reviewed. The study then focuses on methods of amalgamating the three dimensional power of kinetic depth X-ray (KDFX) imaging with the materials discrimination of angular dispersive X-ray diffraction (ADXRD), thus providing KDEX with a much needed material specific counterpart. A knowledge of the sample position is essential for the correct interpretation of diffraction signatures. Two different sensor geometries (i.e. circumferential and linear) that are able to collect end interpret multiple unknown material diffraction patterns and attribute them to their respective loci within an inspection volume are investigated. The circumferential and linear detector geometries are hypothesised, simulated and then tested in an experimental setting with the later demonstrating a greater ability at discerning between mixed diffraction patterns produced by differing materials. Factors known to confound the linear diffraction method such as sample thickness and radiation energy have been explored and quantified with a possible means of mitigation being identified (i.e. via increasing the sample to detector distance). A series of diffraction patterns (following the linear diffraction approach) were obtained from a single phantom object that was simultaneously interrogated via KDEX imaging. Areas containing diffraction signatures matched from a threat library have been highlighted in the KDEX imagery via colour encoding and match index is inferred by intensity. This union is the first example of its kind and is called diffraction enhanced KDEX imagery. Finally an additional source of information obtained from object disparity is explored as an alternative means of calculating sample loci. This offers a greater level of integration between these two complimentary techniques as object disparity could be used to reinforce the results produced by the linear diffraction geometry.

Dicken, A.

110

Refractive and diffractive x-ray optical elements  

NASA Astrophysics Data System (ADS)

The planar microelectronics technology, involving lithography and highly anisotropic plasma etching techniques, allows manufacturing high quality refractive and diffractive lenses, which may be used in hard X-ray microprobe and microscopy applications. These silicon lenses are mechanically robust and can withstand high beat load of the white X-ray beam at third generation synchrotron radiation sources. For the first time we designed and manufactured a new type of lenses: kinoform lenses and parabolic lenses with scaled reduction of curvature radii. The theoretical background for such type of lens features is presented. Focusing properties in the terms of focus spot and efficiency of all these lenses were tested at the ESRF beamlines. Magnified imaging with planar lense was realized. Some future developments are discussed.

Snigireva, Irina; Snigirev, Anatoly A.; Kuznetsov, Serguei; Rau, Christoph; Weitkamp, Timm; Shabelnikov, Leonid; Grigoriev, Michail; Yunkin, Vecheslav; Hoffmann, Martin; Voges, Edgar I.

2001-12-01

111

Fabrication, measurement, and analysis of multilayer x- ray diffraction gratings  

NASA Astrophysics Data System (ADS)

I examine the theory and fabrication of lamellar multilayer x-ray diffraction gratings. I use current theory based on the Kirchoff Integral for amplitude gratings and a new equation for phase gratings to analyze current technology multilayer grating performance (where the period/? exceeds 10). I examine the possible fabrication methods and define two general categories (additive: multilayer added to patterned substrate, subtractive: grating etched into multilayer). I conclude the additive approach is superior, leading to x-ray analogues to binary optics and holographic optical elements. I define an additive process in detail and demonstrate the serviceability of the key processes: thermal growth of silicon dioxide on silicon, lithography, a combined plasma-etch and wet-etch. Multilayer fabrication difficulties on patterned substrates are identified, including: mushroom cap growth, and filleting in the grooves. Measurements done at NSLS on 2 amplitude gratings and 1 phase grating are reported. The data is shown to be compatible with the Kirchoff theory.

Hansen, Douglas P.

1997-12-01

112

Diffractive soft and hard X-ray optics  

NASA Astrophysics Data System (ADS)

The Laboratory for Micro- and Nanotechnology provides the essential technologies necessary for the design and fabrication of diffractive x-ray optics for a wide range of applications. Over the past years, a large variety of optics has been fabricated and tested in collaboration with a large number of partners. To ensure good performance of the devices, they have to be tailored to the specific needs of a specific x-ray optical experiment in terms of photon energy and spatial coherence of the source, as well as required spatial resolution, working distance and diffraction efficiency. We report on a selection of such developments including transmission Fresnel phase zone plates for microscopy or microprobe applications at photon energies ranging from the EUV to the multi-keV region. For photon energies beyond 10 keV transmission zone plates are very rarely used. Our recent development of linear optics with ultra high aspect ratio structures has opened up a way to extend the applications of diffractive optics at least to the 30 keV range. Besides focusing elements, other diffractive optics such as decoherers or beam splitters for interferometric applications are presented.

David, C.; N鰄ammer, B.; Solak, H. H.; Glaus, F.; Haas, B.; Grubelnik, A.; Dolocan, A.; Ziegler, E.; Hignette, O.; Burghammer, M.; Kaulich, B.; Susini, J.; Bongaerts, J. H. H.; van der Veen, J. F.

2003-03-01

113

Identifications studies of Lauha Bhasma by X-ray diffraction and X-ray fluorescence.  

PubMed

Procedures for preparation of Lauha Bhasma are described in ancient texts of Ayurveda. These procedures also begin with different source material for iron such as Teekshna Lauha and Kanta Lauha etc. In the present study, we have selected different source materials viz. magnetite iron ore for Kanta Lauha and pure (Armco grade) iron turnings for Teekshna Lauha. The standard procedures of preparation of Lauha Bhasma are carried out in identical conditions for these two raw materials. The final product from the Puta are characterized by using X-ray diffraction and X-ray fluorescence spectroscopy to understanding the crystallographic form or forms of iron oxides and their composition at the end of each Puta. The iron content at the end of repeated Putas (18 for Kanta Lauha and 20 for Teekshna Lauha) have shown a decrease in case of Teekshna Lauha since the starting material is pure iron while it showed only marginal decreases in the case of Kanta Lauha because the Fe(3)O(4) of magnetite is undergoing oxidation to Fe(2)O(3). The trace elements remain within the Bhasma in the form of various oxides of Si, Al, Ca, etc. PMID:23049200

Bhargava, S C; Reddy, K R C; Sastry, G V S

2012-01-01

114

Identifications studies of Lauha Bhasma by X-ray diffraction and X-ray fluorescence  

PubMed Central

Procedures for preparation of Lauha Bhasma are described in ancient texts of Ayurveda. These procedures also begin with different source material for iron such as Teekshna Lauha and Kanta Lauha etc. In the present study, we have selected different source materials viz. magnetite iron ore for Kanta Lauha and pure (Armco grade) iron turnings for Teekshna Lauha. The standard procedures of preparation of Lauha Bhasma are carried out in identical conditions for these two raw materials. The final product from the Puta are characterized by using X-ray diffraction and X-ray fluorescence spectroscopy to understanding the crystallographic form or forms of iron oxides and their composition at the end of each Puta. The iron content at the end of repeated Putas (18 for Kanta Lauha and 20 for Teekshna Lauha) have shown a decrease in case of Teekshna Lauha since the starting material is pure iron while it showed only marginal decreases in the case of Kanta Lauha because the Fe3O4 of magnetite is undergoing oxidation to Fe2O3. The trace elements remain within the Bhasma in the form of various oxides of Si, Al, Ca, etc. PMID:23049200

Bhargava, S. C.; Reddy, K. R. C; Sastry, G. V. S

2012-01-01

115

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

116

Diffraction line-profile shape by synchrotron and laboratory x-ray sources* Davor Balzar `Jo,Peter W. Stephens 2,and Hassel Ledbetter 1  

E-print Network

, Brookhaven National Laboratory, Upton, NY 11973 and Physics Department, State University of New York, Stony Brook, NY 11794 3On leave from X-ray Laboratory, Division of Materials Research and Electronics, Physics for peak width based on the Gauss approximation for transmission functions of all optical elements fails

Balzar, Davor

117

X-ray weak broad-line quasars: absorption or intrinsic X-ray weakness ?  

NASA Astrophysics Data System (ADS)

We propose seven short observations of X-ray weak quasars, with the aim of understanding the origin of their low X-ray to optical ratio. The sources belong to the spectroscopically selected Hamburg Quasar Survey, and have been observed with Chandra and in the optical. They show unusual optical properties (most of them have a red continuum and very high EW broad emission lines), while the nature of their X-ray weakness (intrinsic or due to absorption ?) is not yet clear, because of the low signal-to-noise of the Chandra spectra. Four short observations with XMM-Newton gave the answer for four sources, showing absorption in two cases, and an unabsorbed spectrum in the other two. This shows that XMM-Newton can unveil the nature of the X-ray emission of these sources.

Risaliti, Guido

2005-10-01

118

Coherent x-ray diffraction imaging of silicon oxide growth  

SciTech Connect

We have measured the morphology of Si samples as a function of time in air after stripping of the native oxide. For this purpose we examined the reflectivity of a coherent beam of x rays, which produces a structured diffraction pattern. We have made further progress in the development of an inversion algorithm for conversion of these patterns into one-dimensional height images. Nanometer-sized features are found to grow and evolve in waves across the surface on the time scale of minutes to hours. {copyright} {ital 1999} {ital The American Physical Society}

Robinson, I.K.; Libbert, J.L. [Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States)] [Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States); Vartanyants, I.A. [Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States)] [Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States); [Institute of Crystallography RAS, Leninsky prospect 59, 117333 Moscow (Russia); Pitney, J.A. [Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States)] [Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States); Smilgies, D.M.; Abernathy, D.L.; Gruebel, G. [European Synchrotron Radiation Facility, 38043 Grenoble (France)] [European Synchrotron Radiation Facility, 38043 Grenoble (France)

1999-10-01

119

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

120

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; Poulsen, H.F. (Denmark)

2012-10-24

121

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

122

Modeling of the M X-ray line structures for tungsten and L X-ray line structures for molybdenum  

NASA Astrophysics Data System (ADS)

Modeled within the Collisional-Radiative approach, for parameters relevant to plasmas in the centre of JET, the M X-ray line structures for tungsten and L X-ray line structures for molybdenum both occur in the wave length range 5.0-5.35 and, their strengths are comparable. Therefore, the spectra obtained with the upgraded high-resolution X-ray spectrometer KX1 on JET should include both tungsten and molybdenum in their interpretation. The same will be true for the high-resolution X- ray diagnostic on tokamaks such as WEST and ITER, where tungsten plasma-facing components will be implemented.

S?abkowska, K.; Polasik, M.; Syrocki, ?.; Szyma?ska, E.; Rzadkiewicz, J.; Pereira, N. R.

2015-01-01

123

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

124

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 ? 1013 W cm-2 pulse by one10 . X-ray free-electron lasers (FELs) are expected to permit diffractive imaging at high

Loss, Daniel

125

Diffraction peaks restoration and extraction in energy dispersive X-ray diffraction Ferrol Souleza,b,1,  

E-print Network

Diffraction peaks restoration and extraction in energy dispersive X-ray diffraction Ferr茅ol Souleza to restore energy dispersive X-ray diffraction (EDXRD) spectra and to extract diffraction peaks. It follows. It separates peaks due to the diffraction by crystalline material from a countinuous background. Tested on real

Paris-Sud XI, Universit茅 de

126

Beam line for experiments with coherent soft x-rays  

SciTech Connect

The advantages of coherent soft x-rays for three-dimensional imaging of biological specimens are discussed, the x-ray source requirements are described, and the general design of the beam line and its optical system are given. (WHK)

Howells, M.R.; Kirz, J.; Krinsky, S.

1982-12-01

127

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

128

Study of pig valve heterografts by x-ray diffraction.  

PubMed

The study of collagen fibers by X-ray diffraction, utilizing semiquantitative indices for appraisal of "structuration" and "orientation" was applied to 30 aortic valve grafts. These grafts, of pig origin, were studied in the fresh state, after tanning with aldehydes, and after having been implanted in patients for at least 18 months. It was shown that the collagen fibers are preferentially orientated parallel to the transverse axis of the valve cusps, and that this arrangement, enhanced by tanning, had a tendency to disappear in the post-implantation samples. The structuration index which concerns the fibril network was also augmented by tanning, and was found a little high or slightly diminished in post-implantation cusps. Evidence for a new compound, probably fibrin, was found in the diffraction patterns of implanted cusps, but crystallized calcium was noticeably absent. PMID:1176472

Huc, A; Planche, C; Weiss, M; Mannschott, P; Chapin, F; Chabrand, D

1975-01-01

129

X-ray Diffraction Spectra in Cu-Implanted SiO{sub 2} Films on Si(100) Substrates  

SciTech Connect

Cu-implanted SiO{sub 2} films on Si(100) have been studied using x-ray methods and x-ray diffraction pattern processing. The x-ray results indicate the presence of a preferred orientation for Cu {l_brace}111{r_brace} planes parallel to the substrate surface without directional orientation for Cu-implanted SiO{sub 2}/Si(100) and nano-crystalline-Cu/SiO{sub 2}/Si(100)(ie. after implanted and annealed Cu). The x-ray diffraction spectra of the Cu-implanted and nano-crystalline-Cu phases were analyzed (ie. in terms of peak search, profile fit, crystallite size) and compared to data from complimentary techniques (RBS, TEM). Results are discussed with respect to x-ray spectral lines shapes derived from XRD spectra processing and the nanostructure problem.

Shirokoff, J. [Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John's, Newfoundland, A1B 3X5 (Canada); Lewis, J. Courtenay [Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, Newfoundland, A1B 3X7 (Canada)

2010-10-29

130

Diffractive-refractive optics: X-ray splitter.  

PubMed

The possibility of splitting a thin (e.g. undulator) X-ray beam based on diffraction-refraction effects is discussed. The beam is diffracted from a crystal whose diffracting surface has the shape of a roof with the ridge lying in the plane of diffraction. The crystal is cut asymmetrically. One half of the beam impinges on the left-hand part of the roof and the other half impinges on the right-hand side of the roof. Owing to refraction the left part of the beam is deviated to the left whereas the right part is deviated to the right. The device proposed consists of two channel-cut crystals with roof-like diffraction surfaces; the crystals are set in a dispersive position. The separation of the beams after splitting is calculated at a distance of 10 m from the crystals for various asymmetry and inclination angles. It is shown that such a splitting may be utilized for long beamlines. Advantages and disadvantages of this method are discussed. PMID:20029121

Hrd, Jarom韗

2010-01-01

131

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

132

X-ray Diffraction and Polarized X-ray Absorption Study of Single Crystal LiFePO4  

Microsoft Academic Search

Large size LiFePO4 single crystals have been grown by standard flux growth technique with the LiCl as the flux. Single crystal x-ray diffraction (XRD) and synchrotron polarized x-ray absorption spectroscopy (XAS) measurements have been performed on the crystals. The XRD measurements were performed at T = 293 K using Mo Kalpha radiation (lambda = 0.7107) to a resolution corresponding to

Gan Liang; Ron Benson; Jiying Li; David Vaknin; Mark Croft

2006-01-01

133

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

134

X-Ray Diffraction and Imaging Study of Imperfections of Crystallized Lysozyme with Coherent X-Rays  

NASA Technical Reports Server (NTRS)

Phase-sensitive x-ray diffraction imaging and high angular-resolution diffraction combined with phase contrast radiographic imaging are employed to characterize defects and perfection of a uniformly grown tetragonal lysozyme crystal in symmetric Laue case. The fill width at half-maximum (FWHM) of a 4 4 0 rocking curve measured from the original crystal is approximately 16.7 arcseconds, and defects, which include point defects, line defects, and microscopic domains, have been clearly observed in the diffraction images of the crystal. The observed line defects carry distinct dislocation features running approximately along the <110> growth front, and they have been found to originate mostly at a central growth area and occasionally at outer growth regions. Individual point defects trapped at a crystal nucleus are resolved in the images of high sensitivity to defects. Slow dehydration has led to the broadening of the 4 4 0 rocking curve by a factor of approximately 2.4. A significant change of the defect structure and configuration with drying has been revealed, which suggests the dehydration induced migration and evolution of dislocations and lattice rearrangements to reduce overall strain energy. The sufficient details of the observed defects shed light upon perfection, nucleation and growth, and properties of protein crystals.

Hu, Zheng-Wei; Chu, Y. S.; Lai, B.; Cai, Z.; Thomas, B. R.; Chernov, A. A.

2003-01-01

135

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

Microsoft Academic Search

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

Anna Zar體; Bo Zhou; Xianqin Wang; Rodolfo Pinal; Zafar Iqbal

2011-01-01

136

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

137

A New Furnace For High-Temperature Synchrotron X-ray Powder Diffraction Experiments - Electron Density Analysis By Powder X-ray Diffraction At 1300 deg. C  

SciTech Connect

A new furnace for synchrotron X-ray powder diffraction experiments in a high-temperature range up to 1600 deg. C has been developed in order to obtain the detailed crystallographic information around high-temperature structural phase transition for the diffractometer of the beam-line 3A at the Photon Factory. The new furnace optical design is based on the flat-specimen reflection geometry using a parallel beam. We have successfully acquired the electron density distribution map of CaTiO3 at about 1300 deg. C with this new furnace using Rietveld and maximum-entropy-method analysis.

Tanaka, Masahiko; Mori, Takeharu [Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Oho, Tsukuba Ibaraki, 305-0801 (Japan); Yashima, Masatomo [Department of Material Science and Engineering, Interdisciplinary Graduate School and Engineering, Tokyo Institute of Technology 4259 Nagatuta-cho, Midori-ku, Yokohama 226-8502 (Japan)

2004-05-12

138

Structured illumination for compressive x-ray diffraction tomography  

NASA Astrophysics Data System (ADS)

Coherent x-ray scatter (also know as x-ray diffraction) has long been used to non-destructively investigate the molecular structure of materials for industrial, medical, security, and fundamental purposes. Unfortunately, molecular tomography based on coherent scatter typically requires long scan times and/or large incident fluxes, which has limited the practical applicability of such schemes. One can overcome the conventional challenges by employing compressive sensing theory to optimize the information obtained per incident photon. We accomplish this in two primary ways: we use a coded aperture to structure the incident illumination and realize massive measurement parallelization and use photon-counting, energy-sensitive detection to recover maximal information from each detected photon. We motivate and discuss here the general imaging principles, investigate different coding and sampling strategies, and provide results from theoretical studies for our structured illumination scheme. We find that this approach promises real-time molecular tomography of bulk objects without a loss in imaging performance.

Greenberg, Joel A.; Brady, David J.

2013-03-01

139

X-ray diffraction characterization of thin superconductive films  

SciTech Connect

The physical and mechanical properties of thin films are often different from the properties of bulk material and are dictated by the film/substrate orientation relationship, crystal anisotropy and crystalgraphic texture of the film. X-ray diffraction texture analysis provides information about preferential film growth and can be used for optimization of deposition parameters and prediction of properties of thin films. An x-ray back reflection technique using the Braga-Brentano geometry with experimental corrections for absorption and defocusing was used to study thin ceramic films deposited by combustion chemical vapor deposition (CCVD). The film/substrate orientation relationships of YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) superconducting thin films deposited via CCVD on single crystal MgO and polycrystalline silver substrates were studied. The as-deposited films on single crystal (100) MgO substrates showed strong preferential growth with the basal plane parallel to the substrate surface (c-axis up growth). Texture analysis showed two in-plane alignment orientations of the film with respect to the substrate, with YBCO [100] and [110] aligned with the [100] MgO substrate. YBCO films deposited on cold-rolled polycrystalline silver displayed c-axis up growth indicating that the orientation of the polycrystalline substrate (brass type texture) did not induce detectable in-plane preferential growth of the YBCO.

Kozaczek, K.J.; Watkins, T.R. [Oak Ridge National Lab., TN (United States); Book, G.W.; Carter, W.B. [Georgia Institute of Technology, Atlanta, GA (United States). School of Materials Science and Engineering

1995-12-31

140

The first X-ray diffraction measurements on Mars  

PubMed Central

The Mars Science Laboratory landed in Gale crater on Mars in August 2012, and the Curiosity rover then began field studies on its drive toward Mount Sharp, a central peak made of ancient sediments. CheMin is one of ten instruments on or inside the rover, all designed to provide detailed information on the rocks, soils and atmosphere in this region. CheMin is a miniaturized X-ray diffraction/X-ray fluorescence (XRD/XRF) instrument that uses transmission geometry with an energy-discriminating CCD detector. CheMin uses onboard standards for XRD and XRF calibration, and beryl:quartz mixtures constitute the primary XRD standards. Four samples have been analysed by CheMin, namely a soil sample, two samples drilled from mudstones and a sample drilled from a sandstone. Rietveld and full-pattern analysis of the XRD data reveal a complex mineralogy, with contributions from parent igneous rocks, amorphous components and several minerals relating to aqueous alteration. In particular, the mudstone samples all contain one or more phyllosilicates consistent with alteration in liquid water. In addition to quantitative mineralogy, Rietveld refinements also provide unit-cell parameters for the major phases, which can be used to infer the chemical compositions of individual minerals and, by difference, the composition of the amorphous component. PMID:25485131

Bish, David; Blake, David; Vaniman, David; Sarrazin, Philippe; Bristow, Thomas; Achilles, Cherie; Dera, Przemyslaw; Chipera, Steve; Crisp, Joy; Downs, R. T.; Farmer, Jack; Gailhanou, Marc; Ming, Doug; Morookian, John Michael; Morris, Richard; Morrison, Shaunna; Rampe, Elizabeth; Treiman, Allan; Yen, Albert

2014-01-01

141

The first X-ray diffraction measurements on Mars.  

PubMed

The Mars Science Laboratory landed in Gale crater on Mars in August 2012, and the Curiosity rover then began field studies on its drive toward Mount Sharp, a central peak made of ancient sediments. CheMin is one of ten instruments on or inside the rover, all designed to provide detailed information on the rocks, soils and atmosphere in this region. CheMin is a miniaturized X-ray diffraction/X-ray fluorescence (XRD/XRF) instrument that uses transmission geometry with an energy-discriminating CCD detector. CheMin uses onboard standards for XRD and XRF calibration, and beryl:quartz mixtures constitute the primary XRD standards. Four samples have been analysed by CheMin, namely a soil sample, two samples drilled from mudstones and a sample drilled from a sandstone. Rietveld and full-pattern analysis of the XRD data reveal a complex mineralogy, with contributions from parent igneous rocks, amorphous components and several minerals relating to aqueous alteration. In particular, the mudstone samples all contain one or more phyllosilicates consistent with alteration in liquid water. In addition to quantitative mineralogy, Rietveld refinements also provide unit-cell parameters for the major phases, which can be used to infer the chemical compositions of individual minerals and, by difference, the composition of the amorphous component. PMID:25485131

Bish, David; Blake, David; Vaniman, David; Sarrazin, Philippe; Bristow, Thomas; Achilles, Cherie; Dera, Przemyslaw; Chipera, Steve; Crisp, Joy; Downs, R T; Farmer, Jack; Gailhanou, Marc; Ming, Doug; Morookian, John Michael; Morris, Richard; Morrison, Shaunna; Rampe, Elizabeth; Treiman, Allan; Yen, Albert

2014-11-01

142

Association of X-ray arches with chromospheric neutral lines  

Microsoft Academic Search

Daily maps of magnetic neutral lines derived from Ha observations have been superimposed on solar X-ray images for the period 1530 June 1973. Nearly all X-ray-emitting structures consist of systems of arches covering chromospheric neutral lines. Areas of low emissivity, coronal holes, appear as the areas between arcades of arches. The presence of a coronal hole, therefore, is determined by

Patrick S. McIntosh; A. S. Krieger; J. T. Nolte; G. Vaiana

1976-01-01

143

High pressure x-ray diffraction study of tungsten disulfide  

SciTech Connect

Synchrotron X-ray diffraction was used in conjunction with a diamond anvil cell to investigate the properties of tungsten disulfide (WS{sub 2}) to 25.5 GPa at room temperature. No pressure medium was used to generate hydrostatic pressure. No phase transformation was observed in the pressure range studied. By fitting the pressure-volume data to the third-order Birch-Murnaghan equation of state, the bulk modulus was determined to be K{sub 0T}=61{+-}1 GPa with its pressure derivative K{prime}{sub 0T}=9.0{+-}0.3. It is also found that the c-direction of the hexagonal structure is much more compressible than the a-direction.

Selvi,E.; Ma, Y.; Aksoy, R.; Ertas, A.; White, A.; Sandhu, J.

2006-01-01

144

High pressure X-ray diffraction study of tungsten disulfide  

NASA Astrophysics Data System (ADS)

Synchrotron X-ray diffraction was used in conjunction with a diamond anvil cell to investigate the properties of tungsten disulfide (WS2) to 25.5 GPa at room temperature. No pressure medium was used to generate hydrostatic pressure. No phase transformation was observed in the pressure range studied. By fitting the pressure-volume data to the third-order Birch-Murnaghan equation of state, the bulk modulus was determined to be K0T=611 GPa with its pressure derivative K?0T=9.00.3. It is also found that the c-direction of the hexagonal structure is much more compressible than the a-direction.

Selvi, Emre; Ma, Yanzhang; Aksoy, Resul; Ertas, Atila; White, Allen

2006-09-01

145

Special properties of X-ray diffraction on carbon onions  

SciTech Connect

The kinematic theory of X-ray diffraction was applied to the study of the most intense Bragg's reflection observed for carbon onions. It was shown that the agreement with experimental data was attained using a convolution of a Lorentzian contour with regard to the distribution of onion sizes and of an asymmetric contour taking into account the fluctuations of intershell distances inside the particle. It can be assumed that the observed scatter in intershell distances indicates a nonequilibrium state of the internal configuration of onion shells. It appeared to be possible to estimate not only the average onion size, which exceeds the average size of pristine nanodiamonds that are used for onion preparation by annealing, but their size distribution function as well.

Yastrebov, S. G., E-mail: yastrebov@mail.ioffe.ru; Ivanov-Omskii, V. I. [Russian Academy of Sciences, Ioffe Physicotechnical Instutute (Russian Federation)

2007-12-15

146

Partially coherent x-ray diffractive imaging of complex objects  

NASA Astrophysics Data System (ADS)

Lack of both spatial and temporal coherence at present x-ray light sources has hindered the application of coherent diffractive imaging techniques, as the computational algorithms which solve the phase problem to invert coherent speckle patterns have traditionally required fully coherent illumination. For this reason, new algorithms which incorporate knowledge of the illumination's coherence properties have been developed and shown to improve the reconstructed image of the scatterer in relatively simple test systems. In this paper we examine the performance of a reconstruction algorithm which incorporates knowledge of the spatial coherence of the illumination in the case of samples with complicated phase structure, and find that even perfect knowledge of the illumination's coherence does not improve the reconstructed image. We speculate that this failure to improve the reconstruction results from an underdetermination of the phase problem in the case of partially coherent illumination.

Parks, D. H.; Shi, X.; Kevan, S. D.

2014-06-01

147

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

148

X-ray diffraction from ion implanted zones  

SciTech Connect

Measurements of x-ray profiles and diffuse scattering from (111), (100) single crystal Niobium films implanted with Nitrogen to average levels of 5 and 0.5 atomic percent are discussed. Theoretical analysis of the asymmetric profiles are used to determine the strain profile in the implanted films. The measured strain profile results from two factors: (1) depth distribution of implants and knock-on damage and (2) elastic constraints. Residual elastic strains develop due to the constraints imposed by a sapphire substrate. Comparison of the diffraction results with theoretical predictions of TRIM indicates the presence of measurable knock-on damage in the films. Huang and Stokes-Wilson scattering measurements made using synchrotron radiation at the ORNL beamline, Brookhaven National Laboratory, were used to reveal the identity of defects formed during the knock-on process.

Rao, S.I.; Houska, C.R.; Grabowski, K.; Claussen, J.; Ice, G.; Habenschuss, A.

1988-01-01

149

Anomalous scattering effects on the invariant phases in near-absorption-edge multiple diffraction of x rays  

Microsoft Academic Search

Effects of anomalous scattering on the invariant phases Psi associated with multiple diffraction are investigated through the alteration of the asymmetry of diffraction lines near the K absorption edges lambdaK for a noncentrosymmetric crystal. The alteration is found to occur when the x-ray wavelength lambda is varied across the absorption edges. It is shown that the alteration of asymmetry is

Shih-Lin Chang

1986-01-01

150

Diffracted X-ray tracking for monitoring intramolecular motion in individual protein molecules using broad band X-ray  

NASA Astrophysics Data System (ADS)

Diffracted X-ray tracking (DXT) enables the tilting and twisting motions of single protein molecules to be monitored with micro- to milliradian resolution using a highly brilliant X-ray source with a wide energy bandwidth. We have developed a technique to monitor single molecules using gold nanocrystals attached to individual protein molecules using the BL28B2 beamline at SPring-8. In this paper we present the installation of a single toroidal X-ray mirror at BL28B2 to focus X-rays in an energy range of 10-20 keV (?E/E = 82% for an X-ray with a wide energy bandwidth). With this beamline we tracked diffraction spots from gold nanocrystals over a wide angle range than that using quasi-monochromatic X-rays. Application of the wide angle DXT technique to biological systems enabled us to observe the on-site motions of single protein molecules that have been functionalized in vivo. We further extend the capability of DXT by observing the fractional tilting and twisting motions of inner proteins under various conditions. As a proof of this methodology and to determine instrumental performance the intramolecular motions of a human serum albumin complex with 2-anthracenecarboxylic acid was investigated using the BL28B2 beamline. The random tilting and twisting intramolecular motions are shown to be directly linked to the movement of individual protein molecules in the buffer solution.

Ichiyanagi, Kouhei; Sekiguchi, Hiroshi; Hoshino, Masato; Kajiwara, Kentaro; Hoshisashi, Kentaro; Jae-won, Chang; Tokue, Maki; Matsushita, Yufuku; Nishijima, Masaki; Inoue, Yoshihisa; Senba, Yasunori; Ohashi, Haruhiko; Ohta, Noboru; Yagi, Naoto; Sasaki, Yuji C.

2013-10-01

151

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPPOWD8 Standard Operating Procedure Title: X-ray Powder Diffraction: D8 Advanced Rev No: Issue date: 1.001 12-ray Powder Diffraction: D8 Advanced PURPOSE: This Standard Operating Procedure (SOP) states

Meagher, Mary

152

Ris-R-747(EN) Neutron and X-Ray Diffraction  

E-print Network

& Ris酶-R-747(EN) Neutron and X-Ray Diffraction from Modulated Structures Pernille Harris Ris酶 National Laboratory, Roskilde, Denmark July 1994 #12;Neutron and X-Ray Diffraction M禄*WW> from Modulated and diverging peak widths as they approach the [001] direction. From the diffraction pattern phase 'A' a small

153

X-ray Diffraction / MSE 603 Spring 2002 Qun Shen / CHESS qs11@cornell.edu  

E-print Network

X-ray Diffraction / MSE 603 Spring 2002 Qun Shen / CHESS qs11@cornell.edu 1. X-ray production & basic properties 颅 common sources for diffraction experiments 颅 synchrotron radiation 颅 response to x. Diffraction from surface structures 颅 specular reflectivity 颅 crystal truncation rod (CTR) 颅 grazing incidence

Shen, Qun

154

Setup for in situ x-ray diffraction study of swift heavy ion irradiated materials.  

PubMed

An in situ x-ray diffraction (XRD) setup is designed and installed in the materials science beam line of the Pelletron accelerator at the Inter-University Accelerator Centre for in situ studies of phase change in swift heavy ion irradiated materials. A high vacuum chamber with suitable windows for incident and diffracted X-rays is integrated with the goniometer and the beamline. Indigenously made liquid nitrogen (LN2) temperature sample cooling unit is installed. The snapshots of growth of particles with fluence of 90 MeV Ni ions were recorded using in situ XRD experiment, illustrating the potential of this in situ facility. A thin film of C60 was used to test the sample cooling unit. It shows that the phase of the C60 film transforms from a cubic lattice (at room temperature) to a fcc lattice at around T=255 K. PMID:18052482

Kulriya, P K; Singh, F; Tripathi, A; Ahuja, R; Kothari, A; Dutt, R N; Mishra, Y K; Kumar, Amit; Avasthi, D K

2007-11-01

155

Setup for in situ x-ray diffraction study of swift heavy ion irradiated materials  

NASA Astrophysics Data System (ADS)

An in situ x-ray diffraction (XRD) setup is designed and installed in the materials science beam line of the Pelletron accelerator at the Inter-University Accelerator Centre for in situ studies of phase change in swift heavy ion irradiated materials. A high vacuum chamber with suitable windows for incident and diffracted X-rays is integrated with the goniometer and the beamline. Indigenously made liquid nitrogen (LN2) temperature sample cooling unit is installed. The snapshots of growth of particles with fluence of 90MeV Ni ions were recorded using in situ XRD experiment, illustrating the potential of this in situ facility. A thin film of C60 was used to test the sample cooling unit. It shows that the phase of the C60 film transforms from a cubic lattice (at room temperature) to a fcc lattice at around T =255K.

Kulriya, P. K.; Singh, F.; Tripathi, A.; Ahuja, R.; Kothari, A.; Dutt, R. N.; Mishra, Y. K.; Kumar, Amit; Avasthi, D. K.

2007-11-01

156

Phosphor Scanner For Imaging X-Ray Diffraction  

NASA Technical Reports Server (NTRS)

Improved optoelectronic scanning apparatus generates digitized image of x-ray image recorded in phosphor. Scanning fiber-optic probe supplies laser light stimulating luminescence in areas of phosphor exposed to x rays. Luminescence passes through probe and fiber to integrating sphere and photomultiplier. Sensitivity and resolution exceed previously available scanners. Intended for use in x-ray crystallography, medical radiography, and molecular biology.

Carter, Daniel C.; Hecht, Diana L.; Witherow, William K.

1992-01-01

157

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 態ragg position even if the 態ragg 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 態ragg 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 態ragg-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 慴ackground. 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

158

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

SciTech Connect

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., E-mail: haughmj@nv.doe.gov; Jacoby, K. D. [National Security Technologies, LLC, Livermore, California 94550 (United States); Wu, M.; Loisel, G. P. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)

2014-11-15

159

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

160

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

161

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.

162

A comparison of different methods for x-ray diffraction line broadening analysis of Ti and Ag UHV deposited thin films: nanostructural dependence on substrate temperature and film thickness  

NASA Astrophysics Data System (ADS)

The influence of substrate temperature and film thickness on the nanostructure of titanium (HCP) and silver (FCC) thin films deposited on glass substrates under UHV conditions by electron beam evaporation is investigated. The preferred orientation, nanostrain and stacking and twin fault probabilities in Ag and Ti films are determined as a function of film thickness and substrate temperature. A (111) preferred orientation is observed for silver films, which is dependent on both the film thickness and substrate temperature, with the highest value at a substrate temperature of 500 K. Ti/glass films showed a (002) preferred orientation. Nanostructural parameters such as the crystallite size (size of coherently diffracting domains) and nanostrain are evaluated using the Scherrer and Stocks-Wilson relations, the Williamson-Hall plot, and the single-Voigt (SV), double-Voigt (DV) and Warren-Averbach (WA) methods. Analysis of the results obtained using these methods showed that the most suitable approaches to x-ray diffraction line broadening analysis, applicable to both FCC and HCP polycrystalline thin film structures, are SV, DV and WA. The results show that the crystallite sizes increase with substrate temperature and film thickness, while the nanostrain and lattice constants decrease with thickness. The crystallite size distribution function was obtained from the size broadened part of the DV function, and the results show a shift in the maximum to larger sizes with increasing temperature and thickness.

Savaloni, H.; Gholipour-Shahraki, M.; Player, M. A.

2006-05-01

163

X-ray Weak Broad-line Qquasars: Absorption or Intrinsic X-ray Weakness  

NASA Technical Reports Server (NTRS)

XMM observations of X-ray weak quasars have been performed during 2003 and 2004. The data for all the observations have become available in 2004 (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 all the data, and obtained interesting scientific results. Out of the eight sources, 4 are confirmed to be extremely X-ray weak, in agreement with the results of previous Chandra observations. 3 sources are confined to be highly variable both in flux (by factor 20-50) and in spectral properties (dramatic changes in spectral index). For both these groups of objects we are completing a publication: 1) For the X-ray weak sources, a paper is submitted with a complete analysis of the X-ray spectra both from Chandra and XMM-Newton, and a comparison with optical and near-IR photometry obtained from all-sky surveys. Possible models for the unusual spectral energy distribution of these sources are also presented. 2) For the variable sources, a paper is being finalized where the X-ray spectra obtained with XMM-Newton are compared with previous X-ray observations and with observations at other wavelengths. It is shown that these sources are high luminosity and extreme cases of the highly variable class of narrow-line Seyfert Is. 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 have been performed in early 2004. They will complement the XMM data and will lead to understanding of whether the X-ray weakness of these sources is an intrinsic property or is due to absorption by circum-nuclear material. The infrared spectra of the variable sources have been already analyzed and are discussed in the paper by Memola et al. which will be soon submitted.

Mushotzky, Richard (Technical Monitor); Risaliti, Guida

2005-01-01

164

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

DOE PAGESBeta

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 degrees 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.

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

2009-11-01

165

X-ray Diffraction Study of Molybdenum to 900 GPa  

NASA Astrophysics Data System (ADS)

Molybdenum (Mo) is a transition metal that is important as a high-pressure standard. Its equation of state, structure, and melting behavior have been explored extensively in both experimental and theoretical studies. Melting data up to the Mbar pressure region from static compression experiments in the diamond anvil cell [Errandonea et al. 2004] are inconsistent with shock wave sound velocity measurements [Hixson et al., 1989]. There are also conflicting reports as to whether body-centered cubic (BCC) Mo transforms to a face-centered cubic (FCC), hexagonal close packed (HCP) or double hexagonal close packed (DHCP) structure at either high pressure or high pressure and temperature conditions [Belonoshko et al. 2008, Mikhaylushkin et al., 2008 and Cazorla et al., 2008]. Recently, a phase transition from BCC to the DHCP phase at 660 GPa and 0 K was predicted using the particle swam optimization (PSO) method (Wang et al, 2013). Here we report an x-ray diffraction study of dynamically compressed molybdenum. Experiments were conducted using the Omega laser at the Laboratory for Laser Energetics at the University of Rochester. Mo targets were either ramp or shock compressed using a laser drive. In ramp loading, the sample is compressed sufficiently slowly that a shock wave does not form. This results in lower temperatures, keeping the sample in the solid state to higher pressures. X-ray diffraction measurements were performed using quasi-monochromatic x-rays from a highly ionized He-? Cu source and image plate detectors. Upon ramp compression, we found no evidence of phase transition in solid Mo up to 900 GPa. The observed peaks can be assigned to the (110) and (200) or (220) reflections of BCC Mo up to the highest pressure, indicating that Mo does not melt under ramp loading to maximum pressure reached. Under shock loading, we did not observe any evidence for the solid-solid phase transformation around 210 GPa as reported in previous work (Hixson et al, 1989). The BCC phase of Mo remained stable along the Hugoniot up to at least 350 GPa. Our observation of diffraction peaks from shocked Mo shows that Hugoniot does not cross the melting curve until at least this pressure. This indicates that previous diamond cell experiments (Errandonea et al., 2004) have underestimated the Mo melting curve. We acknowledge the Omega staff at LLE for their assistance, and the Target Engineering Team at LLNL for fabrication of the targets used in these experiments. The research was supported by NNSA/DOE through the National Laser Users' Facility Program under contracts DE-NA0000856 and DE-FG52-09NA29037. References: [1] R.S. Hixson, D.A. Boness, and J.W. Shaner, Phys. Rev. Lett., 62, 637 (1989). [2] D. Errandonea, B. Schwager, R. Ditz, C. Gessmann, R. Boehler, and M. Ross, Phys. Rev. B, 63, 132104 (2004). [3] A.B. Belonoshko, L. Burakovsky, S.P. Chen, B. Johansson, A.S. Mikhaylushkin, D.L. Preston, S.I. Simak, and D.C. Swift, Phys. Rev. Lett., 100, 135701 (2008). [4] C. Cazorla, D. Alf, and M.J. Gillan, Phys. Rev. Lett. 101, 049601 (2008). [5] A.S. Mikhaylushkin, S.I. Simak ,L. Burakovsky, S.P. Chen, B. Johansson, D.L. Preston, D.C. Swift, and A.B. Belonoshko Phys. Rev. Lett., 101, 049602 (2008). [6] B. Wang, G. Zhang, and Y. Wang, J. Alloys Compd., 556, 116-120, (2013).

Wang, J.; Coppari, F.; Smith, R.; Eggert, J.; Boehly, T.; Collins, G. W.; Duffy, T. S.

2013-12-01

166

The potentialities of X-ray diffraction studies in non-destructive testing  

Microsoft Academic Search

The concept of a non-destructive test is defined. One of the criteria - that the purpose of examination be to relate past history of a particular specimen (or group of specimens) with expected future service performance - is not fulfilled by much conventional X-ray diffraction work. Nevertheless, five groups of X-ray diffraction tests are useful in non-destructive examinations: (i) X-ray

J R Rait; H S Peiser

1957-01-01

167

Quantitative description of microstructure defects in hexagonal boron nitrides using X-ray diffraction analysis  

SciTech Connect

A routine for simultaneous quantification of turbostratic disorder, amount of puckering and the dislocation and stacking fault density in hexagonal materials was proposed and tested on boron nitride powder samples that were synthesised using different methods. The routine allows the individual microstructure defects to be recognised according to their effect on the anisotropy of the X-ray diffraction line broadening. For quantification of the microstructure defects, the total line broadening is regarded as a linear combination of the contributions from the particular defects. The total line broadening is obtained from the line profile fitting. As testing material, graphitic boron nitride (h-BN) was employed in the form of hot-isostatically pressed h-BN, pyrolytic h-BN or a h-BN, which was chemically vapour deposited at a low temperature. The kind of the dominant microstructure defects determined from the broadening of the X-ray diffraction lines was verified by high resolution transmission electron microscopy. Their amount was attempted to be verified by alternative methods. - Highlights: Reliable method for quantification of microstructure defects in BN was suggested. The method is based on the analysis of anisotropic XRD line broadening. This XRD line broadening is unique and characteristic of the respective defect. Thus, the quantification of coexistent microstructure defects is possible. The method was tested on hexagonal BN, which was produced by different techniques.

Schimpf, C., E-mail: schimpf@iww.tu-freiberg.de; Motylenko, M.; Rafaja, D.

2013-12-15

168

Atomic calculations for the Fe XX X-ray lines  

NASA Technical Reports Server (NTRS)

The atomic data presented here and in Bhatia and Mason (1980) allow the calculation of theoretical intensity ratios for all the EUV, UV, and X-ray lines from Fe XX. Tabulations are presently given for the transitions between levels in the 2s2 2p3, 2s2 2p2 3s, and 2s2 2p2 3d configurations of Fe(19+), and electron collision strengths are calculated by means of the 'distorted wave' approximation. In addition to the theoretical X-ray line intensity ratios, new spectral line identifications from a solar flare are presented.

Mason, H. E.; Bhatia, A. K.

1983-01-01

169

X-ray diffraction study of the static strength of tungsten to 69 GPa  

Microsoft Academic Search

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

He Duanwei; Thomas S. Duffy

2006-01-01

170

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

171

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

172

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....

173

X-ray powder diffraction study of the high pressure behaviour of uranium dioxide  

E-print Network

L-171 X-ray powder diffraction study of the high pressure behaviour of uranium dioxide U. Benedict du bioxyde d'uranium sous des pressions jusqu' 40 GPa a 閠 閠udi par diffraction X sur poudre dans une d閘ocalisation d'閘ectrons 5f. Abstract. 2014 Uranium dioxide was studied by X-ray powder

Paris-Sud XI, Universit de

174

In situ X-ray diffraction and X-ray absorption studies of high-rate lithium-ion batteries  

Microsoft Academic Search

A combination of in situ synchrotron X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) was used to study a two-electrode lithium-ion cell made from electrodes from a high-rate lithium-ion battery. The cathode was LiNi0.85Co0.15O2. Both the XRD and the XAS were done in the transmission mode. XAS was done while the cell was charged at the C\\/2 rate to 4.5V.

M Balasubramanian; X Sun; X. Q Yang; J McBreen

2001-01-01

175

Strain measurement of pure titanium covered with soft tissue using X-ray diffraction.  

PubMed

Measurement of the stress and strain applied to implants and bone tissue in the human body are important for fracture prediction and evaluations of implant adaptation. The strain of titanium (Ti) materials can be measuring by X-ray diffraction techniques. This study applied X-ray diffraction to the skin tissue-covered Ti. Characteristic X-rays of Mo Kalpha were used and the X-rays diffracted from the Ti were detected through the covering skin tissue. The X-ray absorption by skin tissue is large under the diffracted X-rays detected in low angles because the length of penetration depends on the angle of inclination, equal to the Bragg angle. The effects of skin tissue to detect the diffracted X-rays were investigated in the experiments. And the strain measurements were conducted under bending loads applied to the Ti specimen. The effect of skin tissue was absorption of X-rays as well as the X-rays scattered from the physiological saline contained in the tissue. The X-rays scattered by the physiological saline creates a specific background pattern near the peaks from the (002) and (011) lattice planes of Ti in the X-ray diffraction profile. Diffracted X-rays from the Ti were detected after being transmitted through 1 mm thick skin tissue by Mo Kalpha. Individual peaks such as (010), (002), (011), and (110) were clearly established by using a parallel beam arrangement. The strains of (110) lattice planes were measured with or without the tissue cover were very similar. The strain of the (110) lattice planes of Ti could be measured by Mo Kalpha when the Ti specimen was located under the skin tissue. PMID:20459192

Fujisaki, Kazuhiro; Tadano, Shigeru

2010-03-01

176

X-ray diffraction study of crystalline barium titanate ceramics  

SciTech Connect

In this study, BaTiO{sub 3} ceramics have been prepared via solid-state reaction method. The powders were calcined for 2 hours at different temperatures ranging from 600癈 to 1200癈. Using X-ray diffraction with a Rietveld analysis, the phase formation and crystal structure of the BaTiO{sub 3} powders were studied. Change in crystallite size and tetragonality as a function of calcination temperature were also discussed. It has been found that the formation of pure perovskite phase of BaTiO{sub 3} began at calcination condition of 1000 癈 for 2 hours. The crystal structure of BaTiO{sub 3} formed is in the tetragonal structure. The second phases of BaCO{sub 3} and TiO{sub 2} existed with calcination temperature below 1000 癈. Purity, crystallite size and tetragonality of BaTiO{sub 3} powders were found to increase with increasing calcination temperature.

Zali, Nurazila Mat; Mahmood, Che Seman; Mohamad, Siti Mariam; Foo, Choo Thye; Murshidi, Julie Adrianny [Malaysian Nuclear Agency, Bangi, 43000 Kajang Selangor (Malaysia)

2014-02-12

177

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

178

Combined synchrotron X-ray tomography and X-ray powder diffraction using a fluorescing metal foil  

SciTech Connect

This study realizes the concept of simultaneous micro-X-ray computed tomography and X-ray powder diffraction using a synchrotron beamline. A thin zinc metal foil was placed in the primary, monochromatic synchrotron beam to generate a divergent wave to propagate through the samples of interest onto a CCD detector for tomographic imaging, thus removing the need for large beam illumination and high spatial resolution detection. Both low density materials (kapton tubing and a piece of plant) and higher density materials (Egyptian faience) were investigated, and elemental contrast was explored for the example of Cu and Ni meshes. The viability of parallel powder diffraction using the direct beam transmitted through the foil was demonstrated. The outcomes of this study enable further development of the technique towards in situ tomography/diffraction studies combining micrometer and crystallographic length scales, and towards elemental contrast imaging and reconstruction methods using well defined fluorescence outputs from combinations of known fluorescence targets (elements).

Kappen, P. [Department of Physics, La Trobe University, Victoria 3086 (Australia); Arhatari, B. D.; Luu, M. B.; Balaur, E. [Department of Physics, La Trobe University, Victoria 3086 (Australia); ARC Centre of Excellence for Coherent X-ray Science, Melbourne (Australia); Caradoc-Davies, T. [Australian Synchrotron, 800 Blackburn Road, Victoria 3168 (Australia)

2013-06-15

179

Combined synchrotron X-ray tomography and X-ray powder diffraction using a fluorescing metal foil.  

PubMed

This study realizes the concept of simultaneous micro-X-ray computed tomography and X-ray powder diffraction using a synchrotron beamline. A thin zinc metal foil was placed in the primary, monochromatic synchrotron beam to generate a divergent wave to propagate through the samples of interest onto a CCD detector for tomographic imaging, thus removing the need for large beam illumination and high spatial resolution detection. Both low density materials (kapton tubing and a piece of plant) and higher density materials (Egyptian faience) were investigated, and elemental contrast was explored for the example of Cu and Ni meshes. The viability of parallel powder diffraction using the direct beam transmitted through the foil was demonstrated. The outcomes of this study enable further development of the technique towards in situ tomography?diffraction studies combining micrometer and crystallographic length scales, and towards elemental contrast imaging and reconstruction methods using well defined fluorescence outputs from combinations of known fluorescence targets (elements). PMID:23822348

Kappen, P; Arhatari, B D; Luu, M B; Balaur, E; Caradoc-Davies, T

2013-06-01

180

Combined synchrotron X-ray tomography and X-ray powder diffraction using a fluorescing metal foil  

NASA Astrophysics Data System (ADS)

This study realizes the concept of simultaneous micro-X-ray computed tomography and X-ray powder diffraction using a synchrotron beamline. A thin zinc metal foil was placed in the primary, monochromatic synchrotron beam to generate a divergent wave to propagate through the samples of interest onto a CCD detector for tomographic imaging, thus removing the need for large beam illumination and high spatial resolution detection. Both low density materials (kapton tubing and a piece of plant) and higher density materials (Egyptian faience) were investigated, and elemental contrast was explored for the example of Cu and Ni meshes. The viability of parallel powder diffraction using the direct beam transmitted through the foil was demonstrated. The outcomes of this study enable further development of the technique towards in situ tomography/diffraction studies combining micrometer and crystallographic length scales, and towards elemental contrast imaging and reconstruction methods using well defined fluorescence outputs from combinations of known fluorescence targets (elements).

Kappen, P.; Arhatari, B. D.; Luu, M. B.; Balaur, E.; Caradoc-Davies, T.

2013-06-01

181

Determination by x-ray microscopy of the phases of the x-ray diffraction by macromolecular structures  

NASA Astrophysics Data System (ADS)

The use of soft x-ray imaging is considered for the determination of the repeating macromolecular structure of biological fibers (e.g., collagen and muscle), within the available image resolution and subject to the effects of radiation damage. A comparison is made between the structure in sarcomere (2 (mu) to 3 (mu) long repeating unit) of striated muscle as seen directly by x-ray microscopy and as derived from published interpretations of x-ray diffraction data from whole muscle. The comparison shows that the loss by radiation damage of the ability of a muscle myofibril to contract is related to the loss of fine structure. Ways to minimize the effects of beam damage are discussed, including the use of images taken in phase, rather than amplitude contrast, and with photon energies above the `water window.'

Burge, Ronald E.; Buckley, Christopher J.; Foster, Guy F.; Bennett, Pauline

1993-01-01

182

Capability of X-ray diffraction for the study of microstructure of metastable thin films  

PubMed Central

Metastable phases are often used to design materials with outstanding properties, which cannot be achieved with thermodynamically stable compounds. In many cases, the metastable phases are employed as precursors for controlled formation of nanocomposites. This contribution shows how the microstructure of crystalline metastable phases and the formation of nanocomposites can be concluded from X-ray diffraction experiments by taking advantage of the high sensitivity of X-ray diffraction to macroscopic and microscopic lattice deformations and to the dependence of the lattice deformations on the crystallographic direction. The lattice deformations were determined from the positions and from the widths of the diffraction lines, the dependence of the lattice deformations on the crystallographic direction from the anisotropy of the line shift and the line broadening. As an example of the metastable system, the supersaturated solid solution of titanium nitride and aluminium nitride was investigated, which was prepared in the form of thin films by using cathodic arc evaporation of titanium and aluminium in a nitrogen atmosphere. The microstructure of the (Ti,Al)N samples under study was tailored by modifying the [Al]/[Ti] ratio in the thin films and the surface mobility of the deposited species. PMID:25485125

Rafaja, David; W黶tefeld, Christina; Dopita, Milan; Motylenko, Mykhaylo; Baehtz, Carsten

2014-01-01

183

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

184

Soft X-ray Excesses and X-ray Line Variability in Cygnus X-3  

NASA Astrophysics Data System (ADS)

Cygnus X-3 is an X-ray binary (XRB) system containing a stellar-mass compact object, most likely a black hole, and a Wolf-Rayet companion star, which produces collimated, relativistic jets, placing it in the sub-class of XRBs known as microquasars. During a Swift/XRT monitoring program of Cygnus X-3, a soft X-ray excess (below 1 keV) was observed at certain states and phases of activity. This soft excess appears to be similar to the variable soft emission observed in Seyfert galaxies. The presence of these features in Cygnus X-3 would argue for a greater support of the black-hole nature of the compact object and serve to better highlight the similarities of microquasars and AGN. We present the results of our investigations of these soft excesses, as well as the variations of the X-ray Fe line region (6.4-7.0 keV) as a function of the state activity and orbital phase.

Varlotta, Angelo; McCollough, Michael L

2014-06-01

185

DIIS: A cross-platform program for the reduction of X-ray diffraction data from a cylindrical area detector  

NASA Astrophysics Data System (ADS)

A new program capable of rapidly and accurately reducing a two-dimensional X-ray diffraction pattern obtained from a Debye-Scherrer or Gandolfi camera to a quantitative digital diffractogram is described. By implementing geometric optimization routines based on the symmetry and sharpness of diffraction lines, the optimal configuration of the camera, X-ray path, and sample can be determined, thus providing the best possible set of integration parameters. Results for NIST standard reference materials 640c (Si) and 676 (Al 2O 3) are included to illustrate program functionality.

Petrus, J. A.; Ross, K. C.; McDonald, A. M.

2012-01-01

186

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

187

Transmission X-ray diffraction grating alignment using a photoelastic modulator  

NASA Technical Reports Server (NTRS)

A high-resolution alignment technique which utilizes the partial polarization property of fine period transmission gratings has been developed. It is especially useful when the grating period is sufficiently small so that there are no visible diffracted orders. This technique uses a photoelastic modulator (PEM) to produce an intensity signal that is proportional to the sine of twice the angle between the grating lines and the PEM crystal axis. The experimentally demonstrated resolution of this technique on 200-nm period gold transmission gratings is better than 1 arc sec. This technique was developed to align X-ray transmission gratings for spectroscopy and interferometry applications.

Anderson, Erik H.; Levine, Alan M.; Schattenburg, Mark L.

1988-01-01

188

Retrieval of the atomic displacements in the crystal from the coherent X-ray diffraction pattern.  

PubMed

The retrieval of spatially resolved atomic displacements is investigated via the phases of the direct(real)-space image reconstructed from the strained crystal's coherent X-ray diffraction pattern. It is demonstrated that limiting the spatial variation of the first- and second-order spatial displacement derivatives improves convergence of the iterative phase-retrieval algorithm for displacements reconstructions to the true solution. This approach is exploited to retrieve the displacement in a periodic array of silicon lines isolated by silicon dioxide filled trenches. PMID:24971974

Minkevich, A A; K鰄l, M; Escoubas, S; Thomas, O; Baumbach, T

2014-07-01

189

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

190

Anti-contamination device for cryogenic soft X-ray diffraction microscopy  

DOE PAGESBeta

Cryogenic microscopy allows one to view frozen hydrated biological and soft matter specimens with good structural preservation and a high degree of stability against radiation damage. We describe a liquid nitrogen-cooled anti-contamination device for cryogenic X-ray diffraction microscopy. The anti-contaminator greatly reduces the buildup of ice layers on the specimen due to condensation of residual water vapor in the experimental vacuum chamber. We show by coherent X-ray diffraction measurements that this leads to fivefold reduction of background scattering, which is important for far-field X-ray diffraction microscopy of biological specimens.

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

2011-05-01

191

X-Ray Diffraction Studies on Material Corrosions in Renewable Energy Storage Electrolyzers  

NASA Astrophysics Data System (ADS)

As a core component of the proton exchange water electrolyzer system, membrane electrode assemblies degrade due to the corrosion of the material. This creates a loss of interfacial contact necessary for the electron transports and electrochemical reactions, thus decreasing the performance. X-ray diffraction has been demonstrated to be an effective method that readily provides quantitative information about the phase-composition of solid materials. In this study, a group of materials have been selected and tested in the standard conditions for investigating the corrosion mechanisms with X-ray diffraction. The material lattice parameter and the crystal size were examined by X-ray diffraction spectrum.

Mo, J.; Steen, S. M., Iii; Zhang, F.-Y.

2014-11-01

192

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

193

Influence of conversion material morphology on electrochemistry studied with operando x-ray tomography and diffraction.  

PubMed

X-ray diffraction and X-ray tomography are performed on intermetallic particles undergoing lithiation in a porous electrode. Differences between ensemble phase evolution and that at a single-particle level are explored. It is found that all particles evidence core-shell lithiation; however, particles with internal porosity are more mechanically robust and exhibit less fracture. PMID:25619158

Villevieille, Claire; Ebner, Martin; G髆ez-C醡er, Juan Luis; Marone, Federica; Nov醟, Petr; Wood, Vanessa

2015-03-01

194

X-ray diffraction study of the static strength of tungsten to 69 GPa Duanwei He* and Thomas S. Duffy  

E-print Network

X-ray diffraction study of the static strength of tungsten to 69 GPa Duanwei He* and Thomas S 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

Duffy, Thomas S.

195

X-Ray Spectrum of a Narrow-Line QSO  

NASA Technical Reports Server (NTRS)

During the reporting period, seven papers using ASCA data, supported in whole or in part by this grant, were published or submitted to refereed journals. Their abstracts are given in this report, and the complete bibliographic references are listed in the Appendix. Titles include (1) A Broad-Band X-ray Study of the Geminga Pulsar; (2) ASCA Observations of PSR 1920+10 and PSR 0950+08; (3) X-ray and Optical Spectroscopy of IRAS 20181-2244: Not a Type 2 QSO, but a I Zw I Object; (4) Models for X-ray Emission from Isolated Pulsars; (5) Optical and X-ray Spectroscopy of 1E 0449.4-1823: Demise of the Original Type 2 QSO; (6) The ASCA Spectrum of the Broad-Line Radio Galaxy Pictor A: A Simple Power Law with No Fe Ka Line; and (7) ASCA Spectra of NGC 4388 and ESO 103-G35: Absorption, Reflection, and Variability in Intermediate Type Seyfert Galaxies.

Halpern, Jules P.

1998-01-01

196

Bragg diffraction using a 100ps 17.5 keV x-ray backlighter and the Bragg Diffraction Imager  

SciTech Connect

A new diagnostic for measuring Bragg diffraction from a laser-driven crystal using a 100ps 17.5 kV x-ray backlighter source is designed and tested successfully at the Omega EP laser facility on static Mo and Ta single crystal samples using a Mo Ka backlighter. The Bragg Diffraction Imager (BDI) consists of a heavily shielded enclosure and a precisely positioned beam block, attached to the main enclosure by an Aluminum arm. Image plate is used as the x-ray detector. The diffraction lines from Mo and Ta <222> planes are clearly detected with a high signal-to-noise using the 17.5 keV and 19.6 keV characteristic lines generated by a petawatt-driven Mo foil. This technique will be applied to shock and ramp-loaded single crystals on the Omega EP laser. Pulsed x-ray diffraction of shock- and ramp-compressed materials is an exciting new technique that can give insight into the dynamic behavior of materials at ultra-high pressure not achievable by any other means to date. X-ray diffraction can be used to determine not only the phase and compression of the lattice at high pressure, but by probing the lattice compression on a timescale equal to the 3D relaxation time of the material, information about dislocation mechanics, including dislocation multiplication rate and velocity, can also be derived. Both Bragg, or reflection, and Laue, or transmission, diffraction have been developed for shock-loaded low-Z crystalline structures such as Cu, Fe, and Si using nano-second scale low-energy implosion and He-{alpha} x-ray backlighters. However, higher-Z materials require higher x-ray probe energies to penetrate the samples, such as in Laue, or probe deep enough into the target, as in the case of Bragg diffraction. Petawatt laser-generated K{alpha} x-ray backlighters have been developed for use in high-energy radiography of dense targets and other HED applications requiring picosecond-scale burst of hard x-rays. While short pulse lasers are very efficient at producing high-energy x-rays, the characteristic x-rays produced in these thin foil targets are superimposed on a broad bremsstrahlung background and can easily saturate a detector if careful diagnostic shielding and experimental geometry are not implemented. A new diagnostic has been designed to measure Bragg diffraction from laser-driven crystal targets using characteristic x-rays from a short-pulse laser backlighter on the Omega EP laser. The Bragg Diffraction Imager, or BDI, is a TIM-mounted instrument consisting of a heavily shielded enclosure made from 3/8-inch thick Heavymet (W-Fe-Ni alloy) and a precisely positioned beam bock, attached to the main enclosure by an Aluminum arm. The beam block is made of 1-inch thick, Al-coated Heavymet and serves to block the x-rays directly from the petawatt backlight, while allowing the diffraction x-rays from the crystal to pass to the enclosure. A schematic of the BDI is shown in Fig. 1a. Image plates are used as the x-ray detector and are loaded through the top of the diagnostic in an Aluminum, light-tight cartridge. The front of the enclosure can be fitted with various filters to maximize the diffraction signal-to-noise.

Maddox, B R; Park, H; Hawreliak, J; Comley, A; Elsholz, A; Van Maren, R; Remington, B A; Wark, J

2010-05-13

197

Real-time X-ray Diffraction: Applications to Materials Characterization  

NASA Technical Reports Server (NTRS)

With the high speed growth of materials it becomes necessary to develop measuring systems which also have the capabilities of characterizing these materials at high speeds. One of the conventional techniques of characterizing materials was X-ray diffraction. Film, which is the oldest method of recording the X-ray diffraction phenomenon, is not quite adequate in most circumstances to record fast changing events. Even though conventional proportional counters and scintillation counters can provide the speed necessary to record these changing events, they lack the ability to provide image information which may be important in some types of experiment or production arrangements. A selected number of novel applications of using X-ray diffraction to characterize materials in real-time are discussed. Also, device characteristics of some X-ray intensifiers useful in instantaneous X-ray diffraction applications briefly presented. Real-time X-ray diffraction experiments with the incorporation of image X-ray intensification add a new dimension in the characterization of materials. The uses of real-time image intensification in laboratory and production arrangements are quite unlimited and their application depends more upon the ingenuity of the scientist or engineer.

Rosemeier, R. G.

1984-01-01

198

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

NASA Astrophysics Data System (ADS)

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, ?-2? scanning, fixed ?-2? 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.

B黵gi, J.; Neuenschwander, R.; Kellermann, G.; Molleja, J. Garc韆; Craievich, A. F.; Feugeas, J.

2013-01-01

199

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

PubMed

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, ?-2? scanning, fixed ?-2? 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. PMID:23387690

B黵gi, J; Neuenschwander, R; Kellermann, G; Garc韆 Molleja, J; Craievich, A F; Feugeas, J

2013-01-01

200

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

SciTech Connect

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

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

2003-01-27

201

X-Ray Diffraction Powder Patterns and Thin Section Observations from the Sierra Madera Impact Structure  

NASA Astrophysics Data System (ADS)

X-Ray powder diffraction analysis and thin section observations of carbonate and siliciclastic samples from the Sierra Madera impact structure indicate moderate shock pressures (8 to 30 GPa) were generated during the formation of this crater.

Huson, S. A.; Foit, F. F.; Watkinson, A. J.; Pope, M. C.

2006-03-01

202

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梐 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

203

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

SciTech Connect

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. [Russian Academy of Sciences, Engelhardt Institute of Molecular Biology (Russian Federation)], E-mail: andreeva@eimb.ru

2006-12-15

204

A Bayesian Approach to Surface X-ray Diffraction  

SciTech Connect

We report on the development of an iterative method to directly invert surface x-ray diffraction (SXRD) data and thereby provide a map of electron density in the near-surface region of a solid. We have termed this method PARADIGM, which stands for Phase and Amplitude Recovery And Diffraction Image Generation Method. Significant advances in the PARADIGM theory were made during the grant period, and experimental milestones have also been achieved. The two components of the research program worked in concert, each spurring progress in the other. The method works by iteratively recovering the phases of surface scattering factors. Initially, random phases are assigned to the structure factors. After subtracting off the known bulk component, a Fourier transform converts these factors into an estimate of the real-space electron density map. This map is subjected to a support constraint, which holds that the electron density may only be non-zero near the solid surface. The modified electron density is then subjected to an inverse Fourier transform, and the bulk contributions are added back in. This renders an improved estimate of the phases of the surface structure factors. A constraint in reciprocal space is then applied, namely, the amplitudes of the scattering factors are set equal to the experimentally observed ones. This cycle is repeated, transforming between real and reciprocal space and applying constraints in each, until convergence is reached. The result renders a good initial model of the unknown surface structure. Such a direct method is important because conventional structural refinement methods rely on having a guess of the starting structure that sufficiently good that it may be refined into a model with the correct atomic positions. If the starting model has, for example, the wrong number or identity of atoms in the surface unit cell, it can never refine to the correct model. Even in cases where the starting model contains the correct number and identity of atoms, it is relatively easy for refinement routines to get trapped in false minima; finding a global minimum of a multi-parameter phase space is a notoriously difficult problem. The utility of the present method, then, stems from its ability to, independently of preconceived notions, identify robust starting models for testing by conventional refinement techniques. The method has been shown to work well on three independent experimental data sets. First, the efficacy of the method was demonstrated on a known reconstruction, the well-known missing-row Au(110)-(2x1) surface. The method recovered all known structural features of this reconstruction. Next, the method was applied to two heretofore unknown reconstructions of the Au(110) surface that are induced by Sb adsorption, the c(2x2) and the (rt(3)xrt(3))R54.7 reconstructions. In each case, the direct method provided an excellent starting model for later refinement by conventional means.

Lyman, Paul F.; Saldin, Dilano K.

2006-11-17

205

(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

206

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

207

X-ray diffraction study of the static strength of tungsten to 69GPa  

Microsoft Academic Search

The strength of tungsten was determined under static high pressures to 69GPa 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

Duanwei He; Thomas S. Duffy

2006-01-01

208

X-ray diffraction of HNS. Period covered: April--June 1975  

Microsoft Academic Search

X-ray diffraction data obtained from HNS (hexanitrostilbene) recrystallized from various solvents are reported. The same x-ray diffraction patterns were observed for all of the HNS samples except dioxane. All of the solvents appear to yield HNS of the same crystal structure. The only basic difference appears to be in the crystal size. HNS-I and HNS-II are not polymorphs. The morphology

Blair

1975-01-01

209

Better Living Through Minerals: X-Ray Diffraction of Household Products  

NSDL National Science Digital Library

X-ray diffraction is a quick and valuable tool for identifying minerals. Minerals are an integral portion of our everyday life, in addition to composing our planet! They help bring electricity into our homes and remove our bathtub rings. In this lab, students analyze the X-ray diffraction patterns of three household cleansers, Ajax, White Magic, and Soft Scrub, in order to identify the abrasive minerals in each.

Barb Dutrow

210

APPLICATIONS OF X-RAY DIFFRACTION IN CONSERVATION SCIENCE AND ARCHAEOMETRY  

Microsoft Academic Search

This paper presents case studies that illustrate the usefulness of X-ray diffraction in the field of conservation science and archaeometry. X-ray diffraction was instrumental in discovering new pigments such as a yellow lead silicate sulfate chloride of the ellestadite group found on fresco fragments from an Abbasid structure built in the early eight century A.D. in Jordan; the yellow compound

M.-C. Corbeil

2004-01-01

211

Temperature-dependent X-ray diffraction as a probe of protein structural dynamics  

Microsoft Academic Search

X-ray diffraction at four temperatures from 220 to 300 K coupled with crystallographic refinement yields the mean-square displacements and conformational potentials of all 1,261 non-hydrogen atoms of metmyoglobin. The results are interpreted to indicate a condensed core around the haem, semi-liquid regions towards the outside and a possible pathway for ligands. It is concluded that X-ray diffraction can provide the

Hans Frauenfelder; Gregory A. Petsko; Demetrius Tsernoglou

1979-01-01

212

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

213

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 (Xray 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.

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

2011-10-01

214

X-Ray diffraction study of carriers and deposited metallic catalysts  

Microsoft Academic Search

The possibilities of applying some X-ray diffraction methods in the study of multicomponent highly disperse systems are examined. Such methods include the method based on the radial distribution of atoms (RDA), full-profile X-ray diffraction analysis (FPA), and the method involving the determination of substructural characteristics (MDSC). Examples of the determination of the structural and substructural characteristics of the most important

Ella M Moroz

1992-01-01

215

X-ray Diffraction Crystal Calibration and Characterization  

SciTech Connect

National Security Technologies X-ray Laboratory is comprised of a multi-anode Manson type source and a Henke type source that incorporates a dual goniometer and XYZ translation stage. The first goniometer is used to isolate a particular spectral band. The Manson operates up to 10 kV and the Henke up to 20 kV. The Henke rotation stages and translation stages are automated. Procedures have been developed to characterize and calibrate various NIF diagnostics and their components. The diagnostics include X-ray cameras, gated imagers, streak cameras, and other X-ray imaging systems. Components that have been analyzed include filters, filter arrays, grazing incidence mirrors, and various crystals, both flat and curved. Recent efforts on the Henke system are aimed at characterizing and calibrating imaging crystals and curved crystals used as the major component of an X-ray spectrometer. The presentation will concentrate on these results. The work has been done at energies ranging from 3 keV to 16 keV. The major goal was to evaluate the performance quality of the crystal for its intended application. For the imaging crystals we measured the laser beam reflection offset from the X-ray beam and the reflectivity curves. For the curved spectrometer crystal, which was a natural crystal, resolving power was critical. It was first necessary to find sources of crystals that had sufficiently narrow reflectivity curves. It was then necessary to determine which crystals retained their resolving power after being thinned and glued to a curved substrate.

Michael J. Haugh; Richard Stewart; Nathan Kugland

2009-06-05

216

Structure studies of the R-phase using the X-ray and electron diffraction method  

NASA Astrophysics Data System (ADS)

The R-phase was induced in polycrystalline 50.6at% Ni-Ti and 51.2at% Ni-Ti alloys by deformation of \\varepsilon=5% and annealing at 350癈 for 70 hours. This procedure allowed for a good separation of transformations: B2{to}R and R{to}B19'. The X-ray diffraction patterns were refined with Rietveld method for three structure models of the following space groups: P3, P{-}3 and P31m. The atomic positions were calculated from the Patterson maps determined from the LeBail method. The comparable lowest value of reliability factors was obtained from the Rietveld refinement for P3 and P{-}3 space groups. Electron diffraction patterns registered for basics zones were compared with kinematically calculated models. Profile line analysis was done in rows with significant differences. All results supported the P{-}3 model.

Goryczka, T.; Morawiec, H.

2003-10-01

217

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

218

Three-Dimensional Visualization of a Human Chromosome Using Coherent X-Ray Diffraction  

SciTech Connect

Coherent x-ray diffraction microscopy is a lensless phase-contrast imaging technique with high image contrast. Although electron tomography allows intensive study of the three-dimensional structure of cellular organelles, it has inherent difficulty with thick objects. X rays have the unique benefit of allowing noninvasive analysis of thicker objects and high spatial resolution. We observed an unstained human chromosome using coherent x-ray diffraction. The reconstructed images in two or three dimensions show an axial structure, which has not been observed under unstained conditions.

Nishino, Yoshinori; Ishikawa, Tetsuya [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Takahashi, Yukio [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Imamoto, Naoko; Maeshima, Kazuhiro [Cellular Dynamics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

2009-01-09

219

Structure-induced negatively skewed X-ray diffraction pattern of carbon onions  

NASA Astrophysics Data System (ADS)

The idea is discussed that a gradual change of intershell separation in carbon onions may introduce a negative skewness into the most intense X-ray diffraction band. As an example, the experimental X-ray diffraction pattern of carbon onions is analysed using a weighted Lorentzian X-ray profile broadening model for each intershell separation contributing to the profile. The dependence of the mean radius for carbon onion shells on the intershell spacing between the adjacent shells is derived from the model analysis. Comparison with the internal distribution of atomic density in carbon onions measured with high resolution transmission electron microscopy is discussed.

Siklitskaya, Alexandra; Yastrebov, Sergey; Smith, Roger

2013-10-01

220

Determination of thickness of multiple layer thin films by an x-ray-diffraction technique  

NASA Astrophysics Data System (ADS)

An x-ray-diffraction method for determining the thickness of multiple layer thin films grown on a single-crystal substratre is presented. The equations, based on the kinematical theory of x-ray diffraction and the mosaic crystal model, were developed. As an example of the application of the method, thickness of a double heterostructure system, namely AlAs/AlGaAs/GaAs, were determined. Good agreement was obtained between the results from x-ray measurement and scanning electron microscopy data, demonstrating the high precision of this technique.

Chaudhuri, J.; Hashmi, F.

1994-10-01

221

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPSAMPOW Standard Operating Procedure Title: Mounting Samples for Powder Diffraction Rev No: Issue date: 1.001 12/1/2009 Mounting Samples for Powder Diffraction PURPOSE: This Standard Operating Procedure (SOP) states

Meagher, Mary

222

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University  

E-print Network

X-ray Diffraction Laboratory: Department of Chemistry Texas A & M University Doc. No: SOPPOWCAP Standard Operating Procedure Title: Mounting Samples for Micro Powder Diffraction Rev No: Issue date: 1: 1/1/2009 Mounting Samples for Micro- Powder Diffraction PURPOSE: This Standard Operating Procedure

Meagher, Mary

223

Versatile wide angle diffraction setup for simultaneous wide and small angle x-ray scattering measurements with synchrotron radiation  

SciTech Connect

Here we present a novel, simple, and versatile experimental setup aimed to perform wide angle x-ray scattering (WAXS) measurements alone or in simultaneous combination with small angle x-ray scattering measurements. The design of the WAXS goniometer allows one to obtain high resolution diffraction patterns in a broad angular range. The setup can incorporate a hot stage in order to evaluate temperature resolved experiments. The performance of the equipment has been verified in the BM16 beam line of the European Synchrotron Radiation Facility with different well known samples such as alumina, isotropic film of high density polyethylene (HDPE), and oriented HPDE fiber.

Rueda, D.R.; Garcia-Gutierrez, M.C.; Nogales, A.; Capitan, M.J.; Ezquerra, T.A.; Labrador, A.; Fraga, E.; Beltran, D.; Juanhuix, J.; Herranz, J.F.; Bordas, J. [Instituto de Estructura de la Materia, CSIC, Serrano 119, 28006 Madrid (Spain); LLS, BM16-ESRF, 6 rue Jules Horowitz, BP220, 38043 Grenoble (France)

2006-03-15

224

Versatile wide angle diffraction setup for simultaneous wide and small angle x-ray scattering measurements with synchrotron radiation  

NASA Astrophysics Data System (ADS)

Here we present a novel, simple, and versatile experimental setup aimed to perform wide angle x-ray scattering (WAXS) measurements alone or in simultaneous combination with small angle x-ray scattering measurements. The design of the WAXS goniometer allows one to obtain high resolution diffraction patterns in a broad angular range. The setup can incorporate a hot stage in order to evaluate temperature resolved experiments. The performance of the equipment has been verified in the BM16 beam line of the European Synchrotron Radiation Facility with different well known samples such as alumina, isotropic film of high density polyethylene (HDPE), and oriented HPDE fiber.

Rueda, D. R.; Garc韆-Guti閞rez, M. C.; Nogales, A.; Capit醤, M. J.; Ezquerra, T. A.; Labrador, A.; Fraga, E.; Beltr醤, D.; Juanhuix, J.; Herranz, J. F.; Bordas, J.

2006-03-01

225

Curved anode wire chambers for x-ray diffraction applications  

SciTech Connect

Curved position sensitive proportional detectors are described. The first has a radius of curvature of 135 mm and a 60/sup 0/ angular range. The second has a radius of curvature of 360 mm and a 45/sup 0/ angular range. For high quantum efficiency for x-ray energies up to 60 keV, a relatively large x-ray path and high gas pressure are required. The anode wires are suspended in circular arcs by the interaction of a current flowing through them and a magnetic field provided by two permanent magnets placed above and below the wire running parallel to it over the full length of the curved chambers. Anode wire stability under the combined action of the magnetic and electrostatic forces is discussed. (LEW)

Perez-Mendez, V.; Wiedenbeck, P.; Wagner, C.N.J.; Woelfel, E.

1983-01-01

226

X-ray Diffraction and Polarized X-ray Absorption Study of Single Crystal LiFePO4  

NASA Astrophysics Data System (ADS)

Large size LiFePO4 single crystals have been grown by standard flux growth technique with the LiCl as the flux. Single crystal x-ray diffraction (XRD) and synchrotron polarized x-ray absorption spectroscopy (XAS) measurements have been performed on the crystals. The XRD measurements were performed at T = 293 K using Mo K? radiation (? = 0.7107) to a resolution corresponding to sin?/? = 0.6486 -1, with 2?max = 54.9 . A total number of 1330 reflections were processed with 350 unique data. The obtained crystal structure data were the following: lithium iron (II) phosphate, LiFePO4, orthorhombic, space group Pnma, lattice constants: a = 10.3172 (11) , b = 6.0096(8) , c = 4.6775 (4) , Z = 4, formula weight: 157.76, density: 3.613, ? = 55.562 cm-1. The bond lengths between Fe and O and between P and O were obtained. The polarized XAS was performed at the Fe K-edge with the x-ray E-vector along the a-, b-, and c-axis. The XAS results show that the Fe ions in the LiFePO4 single crystals are divalent. We also observed a big shift in both the energies of the pre-edge 1s -> 3d transition feature and the main edge when the polarization direction of the E-vector changes from along a-axis to along c-axis.

Liang, Gan; Benson, Ron; Li, Jiying; Vaknin, David; Croft, Mark

2006-10-01

227

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

228

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

SciTech Connect

X-ray diffraction microscopy complements other x-ray microscopy methods by being free of lens-imposed radiation dose and resolution limits, and it allows for high-resolution imaging of biological specimens too thick to be viewed by electron microscopy. We report here the highest resolution (11-13 nm) x-ray diffraction micrograph of biological specimens, and a demonstration of molecular-specific gold labeling at different depths within cells via through-focus propagation of the reconstructed wavefield. The lectin concanavalin A conjugated to colloidal gold particles was used to label the ?-mannan sugar in the cell wall of the yeast Saccharomyces cerevisiae. Cells were plunge-frozen in liquid ethane and freeze-dried, after which they were imaged whole using x-ray diffraction microscopy at 750 eV photon energy.

Nelson, Johanna [Stony Brook Univ., Stony Brook, NY (United States); Huang, Xiaojing [Stony Brook Univ., Stony Brook, NY (United States); Steinbrener, Jan [Stony Brook Univ., Stony Brook, NY (United States); Shapiro, David [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source; Kirz, Janos [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source; Marchesini, Stephano [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source; Neiman, Aaron M. [Northwestern Univ., Evanston, IL (United States); Turner, Joshua J. [Stony Brook Univ., Stony Brook, NY (United States); Jacobsen, Chris [Stony Brook Univ., Stony Brook, NY (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source; Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source

2010-04-20

229

High-resolution ab initio three-dimensional x-ray diffraction microscopy  

DOE PAGESBeta

Coherent x-ray diffraction microscopy is a method of imaging nonperiodic isolated objects at resolutions limited, in principle, by only the wavelength and largest scattering angles recorded. We demonstrate x-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the three-dimensional diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a nonperiodic object. We also construct two-dimensional images of thick objects with greatly increased depth of focus (without loss of transverse spatial resolution). These methods can be used to image biological and materials science samples at high resolution with x-ray undulator radiation and establishes the techniques to be used in atomic-resolution ultrafast imaging at x-ray free-electron laser sources.

Chapman, Henry N.; Barty, Anton; Marchesini, Stefano; Noy, Aleksandr; Hau-Riege, Stefan P.; Cui, Congwu; Howells, Malcolm R.; Rosen, Rachel; He, Haifeng; Spence, John C.; Weierstall, Uwe; Beetz, Tobias; Jacobsen, Chris; Shapiro, David

2006-01-01

230

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

DOE PAGESBeta

X-ray diffraction microscopy complements other x-ray microscopy methods by being free of lens-imposed radiation dose and resolu- tion limits, and it allows for high-resolution imaging of biological specimens too thick to be viewed by electron microscopy. We report here the highest resolution (1113 nm) x-ray diffraction micrograph of biological specimens, and a demonstration of mole- cular-specific gold labeling at different depths within cells via through-focus propagation of the reconstructed wavefield. The lec- tin concanavalin A conjugated to colloidal gold particles was used to label the ?-mannan sugar in the cell wall of the yeast Saccharomyces cerevisiae. Cells were plunge-frozen in liquid ethane and freeze-dried, after which they were imaged whole using x-ray diffraction microscopy at 750 eV photon energy.

Nelson, J.; Huang, X.; Steinbrener, J.; Shapiro, D.; Kirz, J.; Marchesini, S.; Neiman, A. M.; Turner, J. J.; Jacobsen, C.

2010-04-20

231

An x-ray diffraction method for measuring thicknesses of epitaxial thin films  

NASA Astrophysics Data System (ADS)

An x-ray diffraction technique capable of measuring the thicknesses of epitaxial thin films with high precision is described. The advantages of this method are that it is nondestructive, straightforward, and rapidly performed. The equations, based on the kinematical theory of x-ray diffraction and the mosaic crystal model, were developed. As an example of the application of this method, thicknesses of AlxGa1-xAs thin films on GaAs were determined. The integrated reflected intensities from the film and the substrate were obtained using an x-ray double-crystal diffractometer. Excellent agreement between the results from x-ray measurements and reflection high-energy electron diffraction oscillation data was obtained.

Chaudhuri, J.; Shah, S.; Harbison, J. P.

1989-12-01

232

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

233

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

234

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

NASA Astrophysics Data System (ADS)

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

Sandberg, Richard Lunt

235

Hard X-Ray Spectra of Broad-Line Radio Galaxies from the Rossi X-Ray Timing Explorer  

NASA Astrophysics Data System (ADS)

We present the results of hard X-ray observations of four broad-line radio galaxies (BLRGs) with the Rossi X-Ray Timing Explorer. The original motivation behind the observations was to search for systematic differences between the BLRGs and their radio-quiet counterparts, the Seyfert galaxies. We do, indeed, find that the Fe K? lines and Compton ``reflection'' components, which are hallmarks of the X-ray spectra of Seyfert galaxies, are weaker in BLRGs by about a factor of 2. This observational result is in agreement with the conclusions of other recent studies of these objects. We examine several possible explanations for this systematic difference, including beaming of the primary X-rays away from the accretion disk, a low iron abundance, a small solid angle subtended by the disk to the primary X-ray source, and dilution of the observed spectrum by beamed X-rays from the jet. We find that a small solid angle subtended by the disk to the primary X-ray source is a viable and appealing explanation, while all others suffer from drawbacks. We interpret this as an indication of a difference in the inner accretion disk structure between Seyfert galaxies and BLRGs, namely that the inner accretion disks of BLRGs have the form of an ion-supported torus or an advection-dominated accretion flow, which irradiates the geometrically thin outer disk.

Eracleous, Michael; Sambruna, Rita; Mushotzky, Richard F.

2000-07-01

236

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

NASA Astrophysics Data System (ADS)

We propose to observe a sample of 23 soft X-ray weak, optically red quasars, discovered by the Hamburg Quasar Survey. The lack of detection in the ROSAT PSPC, despite their relatively bright optical emission make them a peculiar class of quasars, classified as type 1 in the optical but type 2 in the X-rays. Establishing the X-ray properties of these objects is important for (1) the X-ray background synthesis models (they could be the missing "QSO2s"), (2) the unified models (they challenge the traditional torus model) and (3) the long debated problem on the discrepancy between optical and X-ray luminosity functions. With 180 ks with ACIS-S we can observe a well defined sample of sources and measure their absorption column density in many cases.

Risaliti, Guido

2001-09-01

237

X-ray diffraction and absorption spectroscopic studies of copper mixed ligand complexes with aminophenol as one of the ligands  

Microsoft Academic Search

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

A Mishra; Garima Jain; H Patil

2012-01-01

238

In situ X-ray diffraction investigation of nanocrystallization of amorphous Co-Fe-Zr-B alloys  

NASA Astrophysics Data System (ADS)

Cobalt-rich soft-magnetic alloys were recently developed as amorphous materials with promising engineering properties, e.g. high mechanical strength, excellent magnetic properties and high corrosion resistance. The crystallization of the as-prepared amorphous alloys plays a crucial role in most technological applications of these advanced soft-magnetic nanomaterials. Amorphous ribbons with nominal composition Co 56Fe 16Zr 8B 20 (at%) were here obtained by single-roller melt spinning. The nucleation and growth of nanoscale phases during constant-rate heating of as-quenched and of high-energy ball-milled Co-rich amorphous soft-magnetic alloys were investigated by differential scanning calorimetry and by in situ high-temperature powder X-ray diffraction using synchrotron radiation. The temperature/time evolution of the crystallite size and of average microstrain was obtained from the X-ray diffraction line-profile analysis (LPA) of the powder diffraction patterns.

Bednar?韐, J.; Nicula, R.; Stir, M.; Burkel, E.

2007-09-01

239

Stress Measurement in Graphite\\/Epoxy Composites By X-Ray Diffraction from Fillers  

Microsoft Academic Search

The purpose of this work was to measure stresses in graphite\\/epoxy composites by diffracting X-rays from crystalline filler particles embedded in unidirectional laminates before curing. Particles used were Ag, Nb and CdO, having sharp diffraction peaks at large diffraction angles, ?. The diffraction peaks shift linearly with applied stress in the fiber direction and have stress sensitivities of (2.6, 3.9

Paul Predecki; Charles S. Barrett

1979-01-01

240

Phase sensitive x-ray diffraction imaging of defects in biological macromolecular crystals  

NASA Technical Reports Server (NTRS)

Conventional x-ray diffraction topography is currently used to map defects in the bulk of protein crystals, but the lack of sufficient contrast is frequently a limiting factor. We experimentally demonstrate that this barrier can be circumvented using a method that combines phase sensitive and diffraction imaging principles. Details of defects revealed in tetragonal lysozyme and cubic ferritin crystals are presented and discussed. The approach enabling the detection of the phase changes of diffracted x rays should prove to be useful in the study of defect structures in a broad range of biological macromolecular crystals.

Hu, Z. W.; Lai, B.; Chu, Y. S.; Cai, Z.; Mancini, D. C.; Thomas, B. R.; Chernov, A. A.

2001-01-01

241

Apparatus for use in examining the lattice of a semiconductor wafer by X-ray diffraction  

NASA Technical Reports Server (NTRS)

An improved apparatus for examining the crystal lattice of a semiconductor wafer utilizing X-ray diffraction techniques was presented. The apparatus is employed in a method which includes the step of recording the image of a wafer supported in a bent configuration conforming to a compound curve, produced through the use of a vacuum chuck provided for an X-ray camera. The entire surface thereof is illuminated simultaneously by a beam of incident X-rays which are projected from a distant point-source and satisfy conditions of the Bragg Law for all points on the surface of the water.

Parker, D. L.; Porter, W. A. (inventor)

1978-01-01

242

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, Gayle A. (Livermore, CA)

1986-01-01

243

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

244

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

245

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

246

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, 41013Wcm-2 pulse, containing 1012

Henry N. Chapman; Anton Barty; Michael J. Bogan; S閎astien Boutet; Matthias Frank; Stefan P. Hau-Riege; Stefano Marchesini; Bruce W. Woods; Sasa Bajt; W. Henry Benner; Richard A. London; Elke Pl鰊jes; Marion Kuhlmann; Rolf Treusch; Stefan D黶terer; Thomas Tschentscher; Jochen R. Schneider; Eberhard Spiller; Thomas M鰈ler; Christoph Bostedt; Matthias Hoener; David A. Shapiro; Keith O. Hodgson; David van der Spoel; Florian Burmeister; Magnus Bergh; Carl Caleman; G鰏ta Huldt; M. Marvin Seibert; Filipe R. N. C. Maia; Richard W. Lee; Abraham Sz鰇e; Nicusor Timneanu; Janos Hajdu

2006-01-01

247

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

Jo鉶 Canotilho; Ricardo A. E. Castro; M醨io T. S. Rosado; M. Ramos Silva; A. Matos Beja; J. A. Paix鉶; J. Sim鮡s Redinha

2008-01-01

248

Proposal of a novel Diffraction Enhanced Imaging setup based on polycapillary X-ray optics  

Microsoft Academic Search

Diffraction Enhanced Imaging (DEI) is a recent technique developed to improve the diagnostic capabilities of radiography by exploiting coherently scattered X-rays to generate images that provide higher contrast than conventional transmission imaging. Earlier experiments, carried out in the synchrotron environment using a mechanical parallel-hole collimator coupled to a 2D X-ray imager, confirmed the potential of this technique in mammography. The

Andrea Castoldi; C. Ozkan; C. Guazzoni; A. Bjeoumikhov; J. Griffiths; G. Royle; R. Hartmann

2008-01-01

249

The effect of laser radiation on the diffraction of X-rays in crystals  

NASA Astrophysics Data System (ADS)

The effect of laser radiation on the intensity of the X-ray diffraction peaks of KDP, ADP, and CuSO4-5H2O crystals was studied experimentally. This intensity was found to increase as a function of the laser beam power. This result suggests that it is possible to use laser beams to control X-ray intensity in the crystals considered.

Trushin, V. N.; Chuprunov, E. V.; Khokhlov, A. F.

1988-10-01

250

Studies of Surface and Thin Film Structures by X-Ray Photoelectron Diffraction  

Microsoft Academic Search

The knowledge of atomic structure in the surface region is essential to the comprehension of surface physical phenomena. In this thesis research, x-ray photoelectron diffraction and Auger electron diffraction (XPD) have been used to study a series of single crystal surface and thin film structures, ranging from simple fcc lattices to more complicated diamond and calcium fluorite structures. The systems

Jian Zhang

1994-01-01

251

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

E-print Network

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

Ihee, Hyotcherl

252

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

253

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.; Ar関alo, 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

254

Measurement of coronal X-ray emission lines from Capella  

NASA Technical Reports Server (NTRS)

The Einstein Observatory's Focal Plane Crystal Spectrometer has detected X-ray emission lines due to O VIII, Fe XVII, and Fe XX, from the binary star system Capella. Line luminosities are well fitted by an emitting plasma at a single temperature of 6.29 + or - 0.01 - 0.03 million K, and a volume emission measure of about 8.6 x 10 to the 52nd/cu cm, corresponding to the low temperature component previously observed. A high temperature component is undetectable, since the observed lines are not produced in plasma at temperatures above about 20 million K. Nearly isothermal plasma would be expected if many of the magnetically confined coronal loops have similar sizes and pressures, and a second population of longer loops would be required to account for the hotter component. An alternative interpretation of the observed X-ray line emission and upper limit is that the plasma contains a continuous distribution of emission measure versus temperature that rises sharply to 3 million K and then falls by nearly a decade to 16 million. An extrapolation of the loop sizes suggested by this alternative to hotter, longer loops may also account for the higher temperature emission.

Vedder, P. W.; Canizares, C. R.

1983-01-01

255

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

256

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抯 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

257

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

258

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

259

Supersymmetric Higgs-portal and X-ray lines  

E-print Network

We consider a Dirac singlet fermion as thermal dark matter for explaining the X-ray line in the context of a supersymmetric Higgs-portal model or a generalized Dirac NMSSM. The Dirac singlet fermion gets a mass splitting due to their Yukawa couplings to two Higgs doublets and their superpartners, Higgsinos, after electroweak symmetry breaking. We show that a correct relic density can be obtained from thermal freeze-out, due to the co-annihilation with Higgsinos for the same Yukawa couplings. We discuss the phenomenology of the Higgsinos in this model such as displaced vertices at the LHC.

Lee, Hyun Min; Park, Myeonghun

2015-01-01

260

Supersymmetric Higgs-portal and X-ray lines  

E-print Network

We consider a Dirac singlet fermion as thermal dark matter for explaining the X-ray line in the context of a supersymmetric Higgs-portal model or a generalized Dirac NMSSM. The Dirac singlet fermion gets a mass splitting due to their Yukawa couplings to two Higgs doublets and their superpartners, Higgsinos, after electroweak symmetry breaking. We show that a correct relic density can be obtained from thermal freeze-out, due to the co-annihilation with Higgsinos for the same Yukawa couplings. We discuss the phenomenology of the Higgsinos in this model such as displaced vertices at the LHC.

Hyun Min Lee; Chan Beom Park; Myeonghun Park

2015-01-29

261

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

2014-10-10

262

Exploring X-ray lines as scotogenic signals  

NASA Astrophysics Data System (ADS)

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 ? ? e?, 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.

Faisel, Gaber; Ho, Shu-Yu; Tandean, Jusak

2014-11-01

263

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

DOE PAGESBeta

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.

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

2009-01-01

264

Effect of amorphous interface layers on crystalline thin-film x-ray diffraction  

NASA Astrophysics Data System (ADS)

In this work, an analysis method of x-ray diffraction data of crystalline structures with amorphous interface layers is presented and applied to single crystalline films on amorphous interface layers. Thickness and morphology of crystalline films are obtained from x-ray diffraction at conditions where no significant interference effects between crystalline film and substrate occur. Extending the x-ray diffraction analysis to conditions where interference effects between the crystalline film and the substrate appear, it is also possible to determine the morphology of the amorphous interface film. The analysis method presented in this work is useful for the current and future analyses of amorphous structures between crystalline structures in general and is therefore applicable to many different material systems. This incorporates crystalline thin and ultrathin films on crystalline substrates as well as crystalline multilayers on crystalline and also on amorphous substrates. We apply the method developed here to characterize both crystalline praseodymia films and amorphous interface layers, which could be detected neither by x-ray reflection nor by x-ray diffraction previously.

Weisemoeller, T.; Bertram, F.; Gevers, S.; Deiter, C.; Greuling, A.; Wollschl鋑er, J.

2009-06-01

265

Combined X-ray and neutron fibre diffraction studies of biological and synthetic polymers.  

SciTech Connect

The fibrous state is a natural one for polymer molecules which tend to assume regular helical conformations rather than the globular structures characteristic of many proteins. Fibre diffraction therefore has broad application to the study of a wide range of biological and synthetic polymers. The purpose of this paper is to illustrate the general scope of the method and in particular to demonstrate the impact of a combined approach involving both X-ray and neutron diffraction methods. While the flux of modern X-ray synchrotron radiation sources allows high quality datasets to be recorded with good resolution within a very short space of time, neutron studies can provide unique information through the ability to locate hydrogen or deuterium atoms that are often difficult or impossible to locate using X-ray methods. Furthermore, neutron fibre diffraction methods can, through the ability to selectively label specific parts of a structure, be used to highlight novel aspects of polymer structure that can not be studied using X-rays. Two examples are given. The first describes X-ray and neutron diffraction studies of conformational transitions in DNA. The second describes structural studies of the synthetic high-performance polymer poly(p-phenylene terephthalamide) (PPTA), known commercially as Kevlar{reg_sign} or Twaron{reg_sign}.

Parrot, I. M. [Institut Laue-Langevin (ILL); Urban, Volker S [ORNL; Gardner, K. H. [DuPont Experimental Station; Forsyth, V. T. [Institut Laue Langevin and Keele University

2005-04-01

266

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

SciTech Connect

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

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

2014-04-15

267

X-Ray Diffraction Techniques for a Field Instrument: Patterns of Lithologic Provences  

NASA Technical Reports Server (NTRS)

Future exploration of Mars will attempt to shed light on the mineralogy of surface materials. Instruments deployed from remote platforms should have the capability to conduct both intensive analyses as well as rapid, reconnaissance surveys while they function in the martian environment as surrogate geologists. In order to accommodate the reconnaissance mode of analysis and to compensate for analytical limitations imposed by the space-flight conditions, data analysis methods are being developed that will permit interpretation of data by recognition of signatures or "fingerprints". Specifically, we are developing a technique which will allow interpretation of diffraction patterns by recognition of characteristic signatures of different lithologic provences. This technique allows a remote vehicle to function in a rapid-scan mode using the lithologic signature to determine where a more thorough analysis is needed. An x-ray diffraction pattern is characterized by the angular positions of diffracted x-rays, x-ray intensity levels and background radiation levels. These elements may be used to identify a generalized x-ray signature. Lithologic signatures are being developed in two ways. A signature is composed using the ideal powder diffraction indices from the mineral assembledge common to a specific lithologic provence. This is then confirmed using a laboratory diffraction pattern of a whole rock powder. Preliminary results comparing the diffraction signatures of the major mineral assembledges common to basalt, carbonate, and evaporite basin deposits indicate that lithologies are differentiable as a "fingerprint". Statistical analyses are being performed to establish the confidence levels of this technique.

Marshall, J.; Keaten, R.

1999-01-01

268

Pump-probe X-ray Diffraction Technique for Irreversible Phase Change Materials  

SciTech Connect

We have developed a pump-probe X-ray diffraction measurement system for a sample with irreversible reaction at BL40XU in the SPring-8. The system mainly consists of a time-resolved measurement system, a sample disk rotation system, and an X-ray microbeam system. The time-resolved measurement system gives time resolution of 50 ps in laser-pump and X-ray probe method. A sample disk rotation system for repetitive measurements was made to give a virgin sample for every measurement. The number of repetitions for one sample disk was increased by using the X-ray microbeam technique. To keep the overlap of the X-ray microbeam and the laser beam on the sample surface during the disk rotation, the sample disk rotation system was constructed by a low-eccentric spindle motor. By using this system, the pump-probe X-ray diffraction measurement was demonstrated for a crystallization process of a DVD material.

Fukuyama, Yoshimitsu; Yasuda, Nobuhiro; Kimura, Shigeru; Osawa, Hitoshi; Kim, Jungeun [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Japan Science and Technology Agency, CREST, 5, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Tanaka, Yoshihito; Takata, Masaki [Japan Science and Technology Agency, CREST, 5, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Murayama, Haruno [Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551 (Japan); Moritomo, Yutaka [Japan Science and Technology Agency, CREST, 5, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8571 (Japan); Toriumi, Koshiro [Japan Science and Technology Agency, CREST, 5, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297 (Japan); Tanaka, Hitoshi [RIKEN XFEL Joint Project/SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2010-06-23

269

X-ray diffraction of krypton and xenon mixtures adsorbed on graphite T. Ceva, M. Goldmann (*) and C. Marti  

E-print Network

1527 X- ray diffraction of krypton and xenon mixtures adsorbed on graphite T. Ceva, M. Goldmann 1986) R茅sum茅. 2014 En 茅tudiant, par diffraction des rayons X, les m茅langes xenon-krypton absorb茅s sur. Abstract 2014 Mixtures of xenon and krypton adsorbed on graphite at 45 K are studied by X ray diffraction

Boyer, Edmond

270

In-situ X-Rays Diffraction and Multiscale Modeling of Shape Memory Alloys M.D. Fall1,*  

E-print Network

-Ray Diffraction (XRD) measurements are performed during tensile tests and heating-cooling cycles. XRD permits, pseudoelasticity, X Ray diffraction (XRD). INTRODUCTION Shape Memory Alloys (SMA) are widely used in many and orientation so that in situ X-Ray Diffraction (XRD) may represent an interesting tool in order to validate

271

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

272

Toward the diffraction limit with transmissive x-ray lenses in astronomy.  

PubMed

We develop an analytical approach to refractive, blazed diffractive, and achromatic x-ray lenses of scalable dimensions for energies from 1 to 20 keV. Based on the parabolic wave equation, their wideband imaging properties are compared and optimized for a given spectral range. Low-Z lens materials for massive cores and rugged alternatives, such as polycarbonate or Si for flat Fresnel components, are investigated with respect to their suitability for diffraction-limited high-energy astronomy. Properly designed "hybrid" combinations can serve as an approach to x-ray telescopes with an enhanced efficiency throughout the whole considered band, nearly regardless of their inherent absorption. PMID:22781239

Braig, Christoph; Predehl, Peter

2012-07-10

273

A framework for 3-D coherent diffraction imaging by focused beam x-ray Bragg ptychography.  

SciTech Connect

We present the framework for convergent beam Bragg ptychography, and, using simulations, we demonstrate that nanocrystals can be ptychographically reconstructed from highly convergent x-ray Bragg diffraction. The ptychographic iterative engine is extended to three dimensions and shown to successfully reconstruct a simulated nanocrystal using overlapping raster scans with a defocused curved beam, the diameter of which matches the crystal size. This object reconstruction strategy can serve as the basis for coherent diffraction imaging experiments at coherent scanning nanoprobe x-ray sources.

Hruszkewycz, S. O.; Holt, M. V.; Tripathi, A.; Maser, J.; Fuoss, P. H. (Center for Nanoscale Materials); ( MSD); (Univ. of California at San Diego)

2011-06-15

274

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; Rouz閑, 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; K黨nel, Kai-Uwe; Maurer, Jochen; Messerschmidt, Marc; Rudek, Benedikt; Starodub, Dmitri G; Th鴊ersen, Jan; Weidenspointner, Georg; White, Thomas A; Stapelfeldt, Henrik; Rolles, Daniel; Chapman, Henry N; K黳per, Jochen

2014-01-01

275

Transmission diffraction-tomography system using a high-energy X-ray tube.  

PubMed

A high-energy bench-top energy dispersive X-ray diffraction (EDXRD) system for 3-dimensional mapping of the crystalline structure and phase transformations in steel is described, for which preliminary data and system development are presented here. The use of precision tungsten slit screens with up to 225 keV X-rays allows for diffraction through samples of 304 L austenitic stainless steel of thickness 3-10 mm, while sample positioning is carried out with a precision goniometer and translation stage system. PMID:19962905

Garrity, D J; Jenneson, P M; Crook, R; Vincent, S M

2010-01-01

276

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

277

Nanoscale imaging of mineral crystals inside biological composite materials using X-ray diffraction microscopy.  

PubMed

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. PMID:18233041

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

2008-01-25

278

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梚ntramuscular fish bone梐t 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

279

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; Rouz閑, 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; K黨nel, K-U; Maurer, J; Messerschmidt, M; Rudek, B; Starodub, D; Th鴊ersen, J; Weidenspointner, G; White, T A; Stapelfeldt, H; Rolles, D; Chapman, H N; K黳per, J

2014-01-01

280

X-Ray diffraction study of carriers and deposited metallic catalysts  

NASA Astrophysics Data System (ADS)

The possibilities of applying some X-ray diffraction methods in the study of multicomponent highly disperse systems are examined. Such methods include the method based on the radial distribution of atoms (RDA), full-profile X-ray diffraction analysis (FPA), and the method involving the determination of substructural characteristics (MDSC). Examples of the determination of the structural and substructural characteristics of the most important catalyst carriers as well as deposited and non-deposited metallic catalysts are presented. The bibliography includes 129 references.

Moroz, Ella M.

1992-02-01

281

X-ray and neutron diffraction determination of residual stresses in a pressed and welded component  

NASA Astrophysics Data System (ADS)

X-ray and neutron diffraction experiments have been carried out, in order to determine the residual stress (RS) field in a pressed and welded mock-up of an engine support for motor-bike technology. Such investigation is suggested by the need to know the stress state of the component after forming and welding. This allows to assess the quality of the first machining and further to theoretically simulate its performances under operation. Results are presented below, showing a good agreement between X-ray and neutron diffraction experiments.

Albertini, G.; Bruno, G.; Fiori, F.; Girardin, E.; Giuliani, A.; Quadrini, E.

2000-03-01

282

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

283

Coherent x-ray diffraction imaging of paint pigmentparticles by scanning a phase plate modulator  

SciTech Connect

We have implemented a coherent x-ray diffraction imaging technique that scans a phase plate to modulate wave-fronts of the x-ray beam transmitted by samples. The method was applied to measure a decorative alkyd paint containing iron oxide red pigment particles. By employing an iterative algorithm for wave-front modulation phase retrieval, we obtained an image of the paint sample that shows the distribution of the pigment particles and is consistent with the result obtained from a transmission x-ray microscope. The technique has been experimentally proven to be a feasible coherent x-ray imaging method with about 120 nm spatial resolution and was shown to work well with industrially relevant specimens.

Chu Y. S.; Chen B.; Zhang F.; Berenguer F.; Bean R.; Kewish C.; Vila-Comamala J.; Rodenburg J.; Robinson I.

2011-10-19

284

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

285

Experimental methods for optimal tuning of bendable mirrors for diffraction-limited soft x-ray focusing  

NASA Astrophysics Data System (ADS)

We report on hands-on experimental methods developed at the Advanced Light Source (ALS) for optimal tuning of mechanically bendable x-ray mirrors for diffraction-limited soft x-ray nano-focusing. For ex situ tuning of the benders for optimal beam-line performance, we use a revised version of the method of characteristic functions recently developed at the ALS optical metrology laboratory. At-wavelength optimal tuning of bendable optics consists of a series of wavefront-sensing tests with increasing accuracy and sensitivity, including modified scanning-slit Hartmann tests. The methods have been experimentally validated at ALS test beamline 5.3.1 and the micro-diffraction beamline 12.3.2 in applications to optimally set bendable Kirkpatrick-Baez mirrors designed for sub-micron focusing.

Yashchuk, V. V.; Merthe, D. J.; Goldberg, K. A.; Artemiev, N. A.; Celestre, R.; Domning, E. E.; Kunz, M.; McKinney, W. R.; Morrison, G. Y.; Smith, B. V.; Tamura, N.

2013-03-01

286

High Resolution Triple Axis X-Ray Diffraction Analysis of II-VI Semiconductor Crystals  

NASA Technical Reports Server (NTRS)

The objective of this research program is to develop methods of structural analysis based on high resolution triple axis X-ray diffractometry (HRTXD) and to carry out detailed studies of defect distributions in crystals grown in both microgravity and ground-based environments. HRTXD represents a modification of the widely used double axis X-ray rocking curve method for the characterization of grown-in defects in nearly perfect crystals. In a double axis rocking curve experiment, the sample is illuminated by a monochromatic X-ray beam and the diffracted intensity is recorded by a fixed, wide-open detector. The intensity diffracted by the sample is then monitored as the sample is rotated through the Bragg reflection condition. The breadth of the peak, which is often reported as the full angular width at half the maximum intensity (FWHM), is used as an indicator of the amount of defects in the sample. This work has shown that high resolution triple axis X-ray diffraction is an effective tool for characterizing the defect structure in semiconductor crystals, particularly at high defect densities. Additionally, the technique is complimentary to X-ray topography for defect characterization in crystals.

Volz, H. M.; Matyi, R. J.

1999-01-01

287

Compact ultrahigh vacuum sample environments for x-ray nanobeam diffraction and imaging  

NASA Astrophysics Data System (ADS)

X-ray nanobeams present the opportunity to obtain structural insight in materials with small volumes or nanoscale heterogeneity. The effective spatial resolution of the information derived from nanobeam techniques depends on the stability and precision with which the relative position of the x-ray optics and sample can be controlled. Nanobeam techniques include diffraction, imaging, and coherent scattering, with applications throughout materials science and condensed matter physics. Sample positioning is a significant mechanical challenge for x-ray instrumentation providing vacuum or controlled gas environments at elevated temperatures. Such environments often have masses that are too large for nanopositioners capable of the required positional accuracy of the order of a small fraction of the x-ray spot size. Similarly, the need to place x-ray optics as close as 1 cm to the sample places a constraint on the overall size of the sample environment. We illustrate a solution to the mechanical challenge in which compact ion-pumped ultrahigh vacuum chambers with masses of 1-2 kg are integrated with nanopositioners. The overall size of the environment is sufficiently small to allow their use with zone-plate focusing optics. We describe the design of sample environments for elevated-temperature nanobeam diffraction experiments demonstrate in situ diffraction, reflectivity, and scanning nanobeam imaging of the ripening of Au crystallites on Si substrates.

Evans, P. G.; Chahine, G.; Grifone, R.; Jacques, V. L. R.; Spalenka, J. W.; Sch黮li, T. U.

2013-11-01

288

Compact ultrahigh vacuum sample environments for x-ray nanobeam diffraction and imaging  

SciTech Connect

X-ray nanobeams present the opportunity to obtain structural insight in materials with small volumes or nanoscale heterogeneity. The effective spatial resolution of the information derived from nanobeam techniques depends on the stability and precision with which the relative position of the x-ray optics and sample can be controlled. Nanobeam techniques include diffraction, imaging, and coherent scattering, with applications throughout materials science and condensed matter physics. Sample positioning is a significant mechanical challenge for x-ray instrumentation providing vacuum or controlled gas environments at elevated temperatures. Such environments often have masses that are too large for nanopositioners capable of the required positional accuracy of the order of a small fraction of the x-ray spot size. Similarly, the need to place x-ray optics as close as 1 cm to the sample places a constraint on the overall size of the sample environment. We illustrate a solution to the mechanical challenge in which compact ion-pumped ultrahigh vacuum chambers with masses of 12 kg are integrated with nanopositioners. The overall size of the environment is sufficiently small to allow their use with zone-plate focusing optics. We describe the design of sample environments for elevated-temperature nanobeam diffraction experiments demonstrate in situ diffraction, reflectivity, and scanning nanobeam imaging of the ripening of Au crystallites on Si substrates.

Evans, P. G., E-mail: evans@engr.wisc.edu; Spalenka, J. W. [Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)] [Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Chahine, G.; Grifone, R.; Jacques, V. L. R.; Sch黮li, T. U. [European Synchrotron Radiation Facility, Grenoble 38043 (France)] [European Synchrotron Radiation Facility, Grenoble 38043 (France)

2013-11-15

289

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

290

Phase retrieval in in-line x-ray phase contrast imaging based on total variation  

E-print Network

Phase retrieval in in-line x-ray phase contrast imaging based on total variation minimization X-ray phase-contrast imaging are aiming to solve an underdetermined linear system of equations of America OCIS codes: (110.7440) X-ray imaging; (100.5070) Phase retrieval; (100.3190) Inverse prob- lems

van Vliet, Lucas J.

291

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

NASA Astrophysics Data System (ADS)

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 癈 to 135 癈; par-tial pressure of oxygen, 1.5 kg/cm2; pH 10.0), the pyrite grains are practically inert. Ap-parently, the amount of pyrite in leach residue is constant in absolute terms. However, its relative percentage changes because the amount of copper and zinc minerals is reduced in the leach residue during progressive leaching. The products formed during the leaching reaction, such as goethite and lead sulfate, tend to increase the weight of the leach residue, and thus the relative weight of pyrite remains nearly unchanged. The ratios of selected line pair intensities of pyrite lines and characteristic (selected) lines of chalcopyrite, sphalerite, and galena are used to establish the oxidative ammonia leaching kinetics of Cu-Zn-Pb bulk concentrates. That is, the variation in the line pair intensity ratios, with time, correlates with the changes in the el-emental concentrations in the leach liquor.

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

1993-12-01

292

The PG X-Ray QSO Sample: Links between the Ultraviolet-X-Ray Continuum and Emission Lines  

NASA Astrophysics Data System (ADS)

Two sets of relationships relate QSO UV to soft X-ray continua with the broad-line region. These are (i) the Baldwin relationships, which are inverse relationships between the broad-line equivalent width and the continuum luminosity, and (ii) Boroson & Green's optical ``Principal Component 1'' relationships, linking steeper soft X-ray spectra with narrower H? emission, stronger H? blue wings, stronger optical Fe II emission, and weaker [O III] ?5007 lines. In order to understand these relationships, we extended the spectra into the UV for 22 QSOs with high-quality soft X-ray spectra. These are from the complete sample of QSOs from the Bright Quasar Survey for which Laor et al. demonstrated strong luminosity and X-ray-optical Principal Component 1 relationships. We show that these extend to a whole new set of UV relationships: Principal Component 1 (in the sense of steeper X-ray spectra) is related to narrower C III] ?1909 lines, larger Si III] ?1892/C III] ?1909 ratios (a high-density indicator), stronger low-ionization lines, and weaker C IV ?1549 but stronger N V ?1240 lines. We speculate that high accretion rates are linked to high columns of dense (~1011 cm-3), nitrogen-enhanced, low-ionization gas from nuclear starbursts. Line width, inverse Fe II-[O III] and inverse Fe II-C IV relationships hint at the geometrical arrangement of this gas. These Principal Component 1 relationships appear to be independent of luminosity and therefore of the Baldwin relationships.

Wills, Beverley J.; Laor, A.; Brotherton, M. S.; Wills, D.; Wilkes, B. J.; Ferland, G. J.; Shang, Zhaohui

1999-04-01

293

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

294

In situ laser heating and radial synchrotron X-ray diffraction ina diamond anvil cell  

SciTech Connect

We report a first combination of diamond anvil cell radialx-ray diffraction with in situ laser heating. The laser-heating setup ofALS beamline 12.2.2 was modified to allow one-sided heating of a samplein a diamond anvil cell with an 80 W yttrium lithium fluoride laser whileprobing the sample with radial x-ray diffraction. The diamond anvil cellis placed with its compressional axis vertical, and perpendicular to thebeam. The laser beam is focused onto the sample from the top while thesample is probed with hard x-rays through an x-ray transparentboron-epoxy gasket. The temperature response of preferred orientation of(Fe,Mg)O is probed as a test experiment. Recrystallization was observedabove 1500 K, accompanied by a decrease in stress.

Kunz, Martin; Caldwell, Wendel A.; Miyagi, Lowell; Wenk,Hans-Rudolf

2007-06-29

295

Coherent X-Ray Diffraction Imaging of Morphology and Strain in Nanomaterials  

NASA Astrophysics Data System (ADS)

The last decade has seen a remarkable surge in x-ray characterization methods (Willmott, An Introduction to Synchrotron Radiation, John Wiley & Sons, Inc., New York, 2011). Imaging with x-rays has evolved from simple radiography, to image internal structure and diagnose injury, to a full-fledged tool for nanoscale characterization (Holt et al., Annu Rev Mater Res 43:1, 2013). Central to this development has been the advent of high-brilliance synchrotron and free electron laser sources of x-rays. The high degree of spacial coherence of the resulting beams has enabled novel imaging methods. Of these, coherent diffraction imaging has proven highly successful at imaging the structure in nano materials (Miao et al., Nature 400:342, 1999). In addition, this imaging method can be combined with Bragg diffraction to image strain with high sensitivity (Pfeifer et al., Nature 442:63, 2006; Robinson and Harder, Nat Mater 8:291, 2009).

Harder, Ross; Robinson, Ian K.

2013-09-01

296

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

SciTech Connect

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. [Max-Born-Institut f黵 Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin (Germany)] [Max-Born-Institut f黵 Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin (Germany)

2014-01-14

297

Data management and visualization of x-ray diffraction spectra from thin film ternary composition spreads  

NASA Astrophysics Data System (ADS)

We discuss techniques for managing and visualizing x-ray diffraction spectrum data for thin film composition spreads which map large fractions of ternary compositional phase diagrams. An in-house x-ray microdiffractometer is used to obtain spectra from over 500 different compositions on an individual spread. The MATLAB software is used to quickly organize the data and create various plots from which one can quickly grasp different information regarding structural and phase changes across the composition spreads. Such exercises are valuable in rapidly assessing the "overall" picture of the structural evolution across phase diagrams before focusing in on specific composition regions for detailed structural analysis. We have also shown that simple linear correlation analysis of the x-ray diffraction peak information (position, intensity and full width at half maximum) and physical properties such as magnetization can be used to obtain insight about the physical properties.

Takeuchi, I.; Long, C. J.; Famodu, O. O.; Murakami, M.; Hattrick-Simpers, J.; Rubloff, G. W.; Stukowski, M.; Rajan, K.

2005-06-01

298

X-ray diffraction of indirect flight muscle from Drosohila in vivo  

SciTech Connect

The indirect flight muscle (IFM) of the fruit fly, Drosophila, represents a powerful model system for integrated structure and function studies because of the ease of genetically manipulating this organism. Recent advances in synchrotron technology have allowed collection of high quality two dimensional x-ray fiber diffraction patterns from the IFM of living fruit flies both at rest and during tethered flight. Based on many decades of x-ray and electron microscopic studies of vertebrate muscle and IFM from the waterbug, Lethocerus, there now exists a framework for interpreting changes in the x-ray diffraction patterns in terms of structural changes at the myofilament level. These developments allow testing of hypotheses concerning muscle function in a truly in vivo system.

Irving, T. (IIT)

2007-02-09

299

Hydrogen atoms in protein structures: high-resolution X-ray diffraction structure of the DFPase  

PubMed Central

Background Hydrogen atoms represent about half of the total number of atoms in proteins and are often involved in substrate recognition and catalysis. Unfortunately, X-ray protein crystallography at usual resolution fails to access directly their positioning, mainly because light atoms display weak contributions to diffraction. However, sub-舗gstrom diffraction data, careful modeling and a proper refinement strategy can allow the positioning of a significant part of hydrogen atoms. Results A comprehensive study on the X-ray structure of the diisopropyl-fluorophosphatase (DFPase) was performed, and the hydrogen atoms were modeled, including those of solvent molecules. This model was compared to the available neutron structure of DFPase, and differences in the protein and the active site solvation were noticed. Conclusions A further examination of the DFPase X-ray structure provides substantial evidence about the presence of an activated water molecule that may constitute an interesting piece of information as regard to the enzymatic hydrolysis mechanism. PMID:23915572

2013-01-01

300

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

301

Protegrin interaction with lipid monolayers: Grazing incidence X-ray diffraction and X-ray reflectivity study  

PubMed Central

Interactions of the antimicrobial peptide protegrin-1 (PG-1) with phospholipid monolayers have been investigated by using grazing incidence X-ray diffraction (GIXD) and specular X-ray reflectivity (XR). The structure of a PG-1 film at the air-aqueous interface was also investigated by XR for the first time. Lipid A, dipalmitoyl-phosphatidylglycerol (DPPG) and dipalmitoyl-phosphatidylcholine (DPPC) monolayers were formed at the air-aqueous interface to mimic the surface of the bacterial cell wall and the outer leaflet of the erythrocyte cell membrane, respectively. Experiments were carried out under constant area conditions where the pressure changes upon insertion of peptide into the monolayer. GIXD data suggest that the greatest monolayer disruption produced by PG-1 is seen with the DPPG system at 20 mN/m since the Bragg peaks completely disappear after introduction of PG-1 to the system. PG-1 shows greater insertion into the lipid A system compared to the DPPC system when both films are held at the same initial surface pressure of 20 mN/m. The degree of insertion lessens at 30 mN/m with both DPPC and DPPG monolayer systems. XR data further reveal that PG-1 inserts primarily in the head group region of lipid monolayers. However, only the XR data of the anionic lipids suggest the existence of an additional adsorbed peptide layer below the head group of the monolayer. Overall the data show that the extent of peptide/lipid interaction and lipid monolayer disruption depends not only on the lipid composition of the monolayer, but the packing density of the lipids in the monolayer prior to the introduction of peptide to the subphase. PMID:19672319

Neville, Frances; Ishitsuka, Yuji; Hodges, Chris S.; Konovalov, Oleg; Waring, Alan J.; Lehrer, Robert; Lee, Ka Yee C.; Gidalevitz, David

2009-01-01

302

Mapping Strain in Nanocrystalline Nitinol: an X-ray Diffraction Method (SULI paper)  

SciTech Connect

Understanding the mechanical properties of biomedical devices is critical in predicting and preventing their failure in the body. Such knowledge is essential, for example, in the design of biomedical stents, which must undergo repeated strain over their ten year lifetimes without breaking. Computational models are used to predict mechanical response of a device, but these models are not complete; there are significant deviations from the predictions, especially when devices are subjected to repeated multi-axial loads. Improving these models requires comparisons with actual measurements of strained nitinol. Local measurements of the full strain tensor can be made using X-ray diffraction techniques, but they are currently limited to materials whose grain size is larger than the X-ray beam size or require several diffraction patterns produced by rotation of the sample. Nitinol stents are nanocrystalline, with grains smaller than any available X-ray beam. We present a method for measuring the local strain in a nanocrystalline material from a single X-ray diffraction pattern by extending current powder diffraction techniques. The components of the strain tensor are mapped onto a displacement ellipsoid, which is then reconstructed from diffraction data through Bragg's law and least-squares fitting. Using simulated diffraction data, we performed sensitivity tests to examine how the accuracy of the method depends on how much of the diffraction pattern is measured. We found that strain can be accurately calculated from measurements of at least three diffraction arcs of at least 20{sup o} in length. Thus we believe that our method is a viable approach to calculating strain provided a sufficient amount of diffraction pattern is recorded.

Bibee, Mathew; /SLAC, SSRL

2006-01-04

303

Magnetic symmetries in neutron and resonant x-ray Bragg diffraction patterns of four iridium oxides  

NASA Astrophysics Data System (ADS)

The magnetic properties of Sr2IrO4, Na2IrO3, Sr3Ir2O7 and CaIrO3 are discussed, principally in the light of experimental data in recent literature for Bragg intensities measured in x-ray diffraction with enhancement at iridium L-absorption edges. The electronic structure factors we report, which incorporate parity-even and acentric entities, serve the immediate purpose of making full use of crystal and magnetic symmetry to refine our knowledge of the magnetic properties of the four iridates from resonant x-ray diffraction data. They also offer a platform on which to interpret future investigations, using dichroic signals, resonant x-ray diffraction and neutron diffraction, for example, as well as ab initio calculations of electronic structure. Unit-cell structure factors, suitable for x-ray Bragg diffraction enhanced by an electric dipole-electric dipole (E1-E1) event, reveal exactly which iridium multipoles are visible, e.g., a magnetic dipole parallel to the crystal c-axis (z-axis) and an electric quadrupole with yz-like symmetry in the specific case of CaIrO3. Magnetic space-groups are assigned to Sr2IrO4, Sr3Ir2O7 and CaIrO3, namely, PIcca, PAban and Cm?cm?, respectively, in the Belov-Neronova-Smirnova notation. The assignment for Sr2IrO4 is possible because of our new high-resolution neutron diffraction data, gathered on a powder sample. In addition, the new data are used to show that the ordered magnetic moment of an Ir4+ ion in Sr2IrO4 does not exceed 0.29(4) ?B. Na2IrO3 has two candidate magnetic space-groups that are not resolved with currently available resonant x-ray data.

Lovesey, S. W.; Khalyavin, D. D.; Manuel, P.; Chapon, L. C.; Cao, G.; Qi, T. F.

2012-12-01

304

The impact of powder X-ray diffraction on mineral science, mineral processing and process  

E-print Network

The impact of powder X-ray diffraction on mineral science, mineral processing and process.8% Australia 8.8% South Africa 8.6% Brazil 3.6% India 2.3% http://minerals.usgs.gov/minerals/pubs Research in this field is a priority Resource sustainability is also important 2 #12;XRD in the Minerals Industry

Magee, Joseph W.

305

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...

306

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

307

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

308

Mass Spectrometric Analysis of Mercury Incorporation into Proteins for X-ray Diffraction  

E-print Network

of incorporation. Here we show that mass spec- trometry is an effective tool for determining the extent of heavyMass Spectrometric Analysis of Mercury Incorporation into Proteins for X-ray Diffraction Phase/ionization mass spectrometry (MALDI-MS) and elec- trospray ionization mass spectrometry (ESI-MS) for as- saying

Chait, Brian T.

309

Interaction between Lipid Monolayers and Poloxamer 188: An X-Ray Reflectivity and Diffraction Study  

E-print Network

Interaction between Lipid Monolayers and Poloxamer 188: An X-Ray Reflectivity and Diffraction Study,20), red blood cell from sickle cell disease (21), etc. Although these results show that P188 is effective in restoring damaged cell mem- branes, the underlying mechanisms have barely been studied until recently (22

Lee, Ka Yee C.

310

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

311

In Situ 3D Coherent X-ray Diffraction Imaging of Shock Experiments: Possible?  

NASA Astrophysics Data System (ADS)

In traditional coherent X-ray diffraction imaging (CXDI), a 2D or quasi-2D object is illuminated by a beam of coherent X-rays to produce a diffraction pattern, which is then manipulated via a process known as iterative phase retrieval to reconstruct an image of the original 2D sample. Recently, there have been dramatic advances in methods for performing fully 3D CXDI of a sample from a single diffraction pattern [Raines et al, Nature 463 214-7 (2010)], and these methods have been used to image samples tens of microns in size using soft X-rays. In this work, I explore the theoretical possibility of applying 3D CXDI techniques to the in situ imaging of the interaction between a shock front and a polycrystal, a far more stringent problem. A delicate trade-off is required between photon energy, spot size, imaging resolution, and the dimensions of the experimental setup. In this talk, I will outline the experimental and computational requirements for performing such an experiment, and I will present images and movies from simulations of one such hypothetical experiment, including both the time-resolved X-ray diffraction patterns and the time-resolved sample imagery.

Barber, John

2011-03-01

312

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

PubMed

Light microscopy has greatly advanced our understanding of nature. The achievable resolution, however, is limited by optical wavelengths to approximately 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 1.5lambda. 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

313

Diffractive lenses for photon energies ranging from the extreme ultraviolet to hard x rays  

NASA Astrophysics Data System (ADS)

Diffractive optics for the x-ray range have to meet the various requirements of experimental set-ups at synchrotron or other light sources. In the case of focusing elements it is essential that the devices are matched to parameters such as the photon energy and spatial coherence of the source, as well as the required spatial resolution, working distance, and diffraction efficiency. In some cases, a suppression of disturbing diffraction orders requires additional features such as an opaque central stop integrated into the lens. The Laboratory for Micro- and Nanotechnology provides the essential technologies necessary for the design and fabrication of diffractive x-ray lenses for a wide range of photon energies and applications. Over the past years, a large variety of optics tailored to the specific needs of x-ray optical experiments have been fabricated and tested. These include transmission Fresnel phase zone plate for microscopy, microprobe, or beam monitoring applications, as well as condensers to increase the flux in waveguiding experiments in the hard x-ray range. An overview of the nanofabrication technologies and a selection of experiments demonstrating the devices performance are presented.

David, Christian; Noehammer, Bernd; Solak, Harun H.; Haas, Bianca; Glaus, Fredy; van der Veen, J. Friso; Schlott, Volker; Bongaerts, Jeroen; Kaulich, Burkhard; Susini, Jean

2001-12-01

314

32Curiosity Uses X-Ray Diffraction to Identify Minerals The Curiosity Rover recently used a  

E-print Network

32Curiosity Uses X-Ray Diffraction to Identify Minerals The Curiosity Rover recently used sample on the surface of Mars. The image to the left shows what this data looks like. The exact radii and s so that the wave crests exactly match up? Problem 4 Suppose that in the Curiosity data

315

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

316

Radial x-ray diffraction of tungsten tetraboride to 86 GPa under nonhydrostatic compression  

E-print Network

Radial x-ray diffraction of tungsten tetraboride to 86 GPa under nonhydrostatic compression Lun December 2012; published online 16 January 2013) Investigations of the equation of state of tungsten moduli and hardness exceed- ing or closing that of diamond. Tungsten tetraboride (WB4) is a candidate

Lin, Jung-Fu "Afu"

317

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...

318

Synchrotron X-ray diffraction study of the room temperature incommensurate phase in graphite-bromine  

E-print Network

L-761 Synchrotron X-ray diffraction study of the room temperature incommensurate phase in graphite-bromine- bromine en second stade 脿 temp茅rature ambiante. Le compos茅 graphite-brome a 茅t茅 pr茅par茅 脿 partir d- perature incommensurate phase in stage-2 graphite-bromine prepared with single crystal graphite in bromine

Paris-Sud XI, Universit茅 de

319

X-ray diffraction investigation of a spin crossover hysteresis loop. P Guionneau1,  

E-print Network

@icmcb-bordeaux.cnrs.fr The nature and the mechanism of the magnetic hysteresis for the thermal spin crossover exhibited by an iron(II) compound is investigated by mean of variable temperature powder and single crystals X-ray diffraction in the spin crossover features according to the nature of the sample powder or single crystal that should

Boyer, Edmond

320

J. Mol. Biol. (1984) 177, 201-206 Some X-ray Diffraction Patterns from  

E-print Network

Ribosomal Subunit from Bacillus stearothermophilus X-ray diffraction patterns of three-dimensional crystals of the large ribosomal subunit from Bacillus stearothemwphilus have been obtained using a synchrotron radiation) and of the large ribosomal subunits from Bacillus stearothermophdlus (Yonath et al., 1980,1983a,b). In all cases

Yonath, Ada E.

321

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

322

Femtosecond time-resolved powder diffraction experiments using hard X-ray free-electron lasers.  

PubMed

In the next decade the scientific community expects a strong impact in physics, chemistry, biology, material research and life sciences by the availability of high-brilliance X-ray radiation from free-electron laser (FEL) sources. In particular, in the field of ultrafast science these new sources will allow new types of experiments, enabling new phenomena to be discovered. Whereas today ultrafast X-ray diffraction experiments are strongly restricted by the limited X-ray flux of current sources of sub-picosecond X-ray pulses, FELs will provide short pulses of typically 10(12) photons with a duration of the order of 100 fs and monochromaticity of 10(-3). Here, the feasibility of time-resolved single-shot powder diffraction experiments using these intense pulses, and the requirements of these experiments, are discussed. The detector count rates are estimated for diffraction from a model compound in a wide q-regime under the special consideration of high resolving power. In the case of LCLS radiation parameters, single-shot experiments will be feasible although high-resolution powder diffraction will require a reduction of the intrinsic FEL radiation bandwidth. PMID:16239753

Blome, C; Tschentscher, Th; Davaasambuu, J; Durand, P; Techert, S

2005-11-01

323

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桳NLS, 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.

Cola鏾, 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

324

Characterization of calcium crystals in Abelia using x-ray diffraction and electron microscopes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Localization, chemical composition, and morphology of calcium crystals in leaves and stems of Abelia mosanensis and A. 譯randiflora were analyzed with a variable pressure scanning electron microscope (VP-SEM) equipped with an X-ray diffraction system, low temperature SEM (LT-SEM) and a transmission ...

325

A-DNA and B-DNA: Comparing Their Historical X-Ray Fiber Diffraction Images  

ERIC Educational Resources Information Center

A-DNA and B-DNA are two secondary molecular conformations (among other allomorphs) that double-stranded DNA drawn into a fiber can assume, depending on the relative water content and other chemical parameters of the fiber. They were the first two forms to be observed by X-ray fiber diffraction in the early 1950s, respectively by Wilkins and

Lucas, Amand A.

2008-01-01

326

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

327

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

328

Quantitative measurement of deformation-induced martensite in 304 stainless steel by X-ray diffraction  

Microsoft Academic Search

A single X-ray diffraction scan is effectively used for identifying and evaluating deformation-induced transformation in 304 austenitic stainless steel. Variations in grain size influence surface constraint and hence the through-thickness transformation response. The initial stage of transformation in this steel is most likely dominated by ?杕artensite formation.

Amar K. De; David C. Murdock; Martin C. Mataya; John G. Speer; David K. Matlock

2004-01-01

329

A wide-beam X-ray source suitable for diffraction enhanced imaging applications  

NASA Astrophysics Data System (ADS)

Research in diffraction-enhanced imaging (DEI), using a synchrotron source with an X-ray flux of 1.410 12 ph/mm 2/s, has shown strong potential in obtaining high-resolution images as compared to conventional radiographs. This research investigates the feasibility of developing a large area circular X-ray source with fluxes comparable to a synchrotron source. The source should be capable of integration into a compact system with peak powers not to exceed 200 kW to be feasible for use in a major medical facility, industrial complex or screening facility (such as cargo or airport). A computational study of a circular concentric filament wide-beam area X-ray source has been investigated in this research. The design features are based on generating electrons from three concentric circular filaments to provide an area electron flux, with a 60 kV accelerating potential and a beam current of up to 3 A. The X-ray target is a grounded stationary oxygen-free copper target with a layer of molybdenum. This target feature differs from standard rotating X-ray targets in conventional X-ray systems. Studies of electron trajectories and their distribution on the target were conducted using the SIMION 3D code. Heat loading and thermal management were studied using heat transfer modules from the coupled FEMLAB multi-physics and MATLAB codes. The Monte Carlo code MCNP 5 was used to obtain the X-ray flux and energy distribution for aluminum and beryllium windows. This computational study shows that this target configuration generates X-rays with photon flux comparable to synchrotron source and sufficient for DEI applications. The maximum target temperature rise is 1357 K after 70 s when cooling the back of the target to liquid nitrogen temperature using cold finger contact, and 325 K for an invaded target, in which liquid nitrogen circulates inside the target.

Kim, Chang H.; Bourham, Mohamed A.; Michael Doster, J.

2006-10-01

330

Investigation of Renal Stones by X-ray and Neutron Diffraction  

NASA Astrophysics Data System (ADS)

Renal stones were investigated by X-ray diffraction. The obtained results showed only one crystal phase in every sample. With the aim to verify eventual availability of second phase (under 3 volume %) the same renal stones were investigated by neutron diffraction. The neutron spectra proved that additional crystal phase was absent in the renal stones. The obtained results are scientific-practical, in aid of the medicine, especially in the case of renal stone disease.

Baeva, M.; Beskrovnyi, A. I.; Boianova, A.; Shelkova, I.

2007-04-01

331

X-ray-diffraction characterization of silicon-on-insulator films  

SciTech Connect

Silicon-on-insulator layers produced by the processes of oxygen implantation into single-crystal silicon substrates, zone melt recrystallization of deposited polysilicon films, and silicon epitaxy on sapphire substrates have been examined by an improved x-ray-diffraction technique. The technique incorporates a position-sensitive x-ray detector placed on the 2{theta} arm of a conventional double-crystal diffractometer, thus allowing the measurement of scattered x-ray intensity in both the incident and diffracted x-ray beam angles simultaneously. X-ray scattering intensity maps plotted in {ital k} space reveal the relative strain and mosaic spread of the silicon overlayers with respect to the (001) silicon substrates. Oxygen-implanted films and graphite strip recrystallized films exhibit mosaic spreads ({lt}{plus minus}0.08{degree} and {plus minus}0.05{degree}, respectively) approaching that of bulk single-crystal Si. The electron-beam-recrystallized films exhibit significantly larger mosaic spreads ({approx}{plus minus}0.52{degree}). These silicon overlayer films all exhibit similar perpendicular strain values with an average of approximately 0.08%. Silicon layers produced by both zone melt recrystallization techniques contain a preferential tilt of the diffraction planes along the recrystallization scan direction with respect to the underlying (001)-oriented silicon substrate. Silicon-on-sapphire samples exhibit both a large mosaic spread ({plus minus}0.18{degree}) and a large perpendicular strain (0.13%). These x-ray results are consistent with crystalline data taken by backscattered electron images and Rutherford ion backscattering.

Thompson, L.R.; Collins, G.J. (Electrical Engineering, Colorado State University, Fort Collins, Colorado (USA)); Doyle, B.L.; Knapp, J.A. (Sandia National Laboratories, Albuquerque, New Mexico (USA))

1991-11-01

332

X-Ray Line Spectroscopy of Massive X-Ray Binaries  

NASA Technical Reports Server (NTRS)

Spectra from ASCA have provided the most, detailed view to date of the X-ray spectral properties of stellar winds in massive X-ray binaries. Using detailed atomic models that account for recombination cascade kinetics, we have reexamined archival data from Vela X-1 and Cen X-3 in the context of simple models of their wind geometries and velocity distributions. Our approach emphasizes apparent differential emission measure (DEM) distributions, and their dependence on orbital phase and wind parameters. A grid of theoretical DEM distributions is used to generate model spectra, which are compared to the data. We obtain good fits, and derive constraints oil the stellar wind parameters. We provide a summary of the method, and show that, even though the companion stars in Vela X-1 and Cen X-3 have comparable mass-loss rates, the winds in these two systems are dramatically different, in character.

Liedahl, D. A.; Sako, M.; Wojdowski, P. S.; Paerels, F.; Kahn, S. M.

2000-01-01

333

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 and X-ray diffraction have been performed for a sample of magnesium-stabilised ACC, which was prepared refinement method has been used to make a model of magnesium-stabilised ACC and the results revealed a fair

Benning, Liane G.

334

Charge Density Wave Dislocation as Revealed by Coherent X-Ray Diffraction D. Le Bolloc'h,1  

E-print Network

Charge Density Wave Dislocation as Revealed by Coherent X-Ray Diffraction D. Le Bolloc'h,1 S. Ravy crystals of the charge density wave (CDW) system K0:3MoO3. The satellite reflections associated dislocation. Beyond charge density wave systems, this experiment shows that coherent x-ray diffraction

Paris-Sud 11, Universit de

335

Structural characterization of a Mo/Si multilayer reflector by means of x-ray diffraction measurements  

E-print Network

of these various structural parameters on the small-angle x-ray diffraction XRD pattern are investigated of the Bragg peaks. Based on the above results, we present an analysis of the experimental XRD data in order microscopy TEM , x-ray diffraction XRD , large- angle XRD, Rutherford backscattering spectroscopy RBS

Kim, Jae-Hoon

336

X-ray powder diffraction study of poly/carbon monofluoride/, CF/1.12/  

NASA Technical Reports Server (NTRS)

Data from X-ray diffraction studies of the poly(carbon monofluoride) with empirical formula CF(1.09-1.15) are reported, and possible intercalation arrangements for the substance are discussed. The data do not conform to true hexagonal symmetry, indicating that the carbon atoms are not coplanar. Each bond angle of carbon is 118.8 deg, and the carbon-carbon distance is 1.47 A. The interlayer distance is 5.76 A. A total absence of (hkl) reflections in the X-ray pattern shows that the separate CF layers are not regularly arranged with respect to one another.

Mahajan, V. K.; Badachhape, R. B.; Margrave, J. L.

1974-01-01

337

Synchrotron X-ray diffraction measurements of single-crystal hydrogen to 26.5 gigapascals  

NASA Technical Reports Server (NTRS)

The crystal structure and equation of state of solid hydrogen have been determined directly to 26.5 gigapascals at room temperature by new synchrotron X-ray diffraction techniques. Solid hydrogen remains in the hexagonal close packed structure under these pressure-temperature conditions and exhibits increasing structural anisotropy with pressure. The pressure-volume curve determined from the X-ray data represents the most accurate experimental measurement of the equation of state to date in this pressure range. The results remove the discrepancy between earlier indirect determinations and provide a new experimental constraint on the molecular-to-atomic transition predicted at higher pressures.

Mao, H. K.; Jephcoat, A. P.; Hemley, R. J.; Finger, L. W.; Zha, C. S.

1988-01-01

338

X-ray diffraction studies of model compounds of thermoplastic polyimides  

NASA Technical Reports Server (NTRS)

Several model compounds which represent aspects of the chemical structure of the Langley Research Center thermoplastic (LARC-TPI) have been synthesized for comparison studies using wide angle X-ray scattering (WAXS) as the discriminatory tool. The model compounds included N-phenylphthalimide, 3,3',4,4'-benzophenonetetracarboxylic diphthalimide, and N,N'-diphenyl-3,3',4,4'-benzophenonetetracarboxylic diphthalimide. X-ray diffraction studies of appropriate model compounds can yield information to aid in the understanding of polymeric crystallographic structure. Crystallinity and physical property changes can thus be induced into materials having complicated structures by chemical and thermal processes.

Wakelyn, N. T.; Pratt, J. R.

1989-01-01

339

Analysis of the strain profile in thin Au/Ni multilayers by x-ray diffraction  

NASA Astrophysics Data System (ADS)

The strain relaxation in Au/Ni multilayers was analyzed in detail using a dynamical theory of x-ray diffraction. The depth profile of strain in the modulation direction was determined by an iterative fitting of the calculated rocking curve with the experimental one. The repeat periods of Au/Ni multilayers used in this study range from 0.82 to 9.0 nm. The analysis indicates that the theoretical x-ray patterns are extremely sensitive to the amount of strain at the interface.

Chaudhuri, J.; Gondhalekar, V.; Jankowski, A. F.

1992-04-01

340

Interaction between Lipid Monolayers and Poloxamer 188: An X-Ray Reflectivity and Diffraction Study  

PubMed Central

The mechanism by which poloxamer 188 (P188) seals a damaged cell membrane is examined using the lipid monolayer as a model system. X-ray reflectivity and grazing-incidence x-ray diffraction results show that at low nominal lipid density, P188, by physically occupying the available area and phase separating from the lipids, forces the lipid molecules to pack tightly and restore the barrier function of the membrane. Upon compression to bilayer equivalent pressure, P188 is squeezed out from the lipid monolayer, allowing a graceful exit of P188 when the membrane integrity is restored. PMID:16100276

Wu, Guohui; Majewski, Jaroslaw; Ege, Canay; Kjaer, Kristian; Weygand, Markus Jan; Lee, Ka Yee C.

2005-01-01

341

X-ray diffraction study of elemental thulium to 86 GPa  

NASA Astrophysics Data System (ADS)

We have studied the structures and equation of state of elemental thulium up to 86 GPa in a diamond anvil cell using angular-dispersive x-ray powder diffraction methods at the Advanced Photon Source. This is part of a study of phase transitions in the lanthanide-series metals using cyclohexane as a quasi-hydrostatic medium. We present evidence of a series of phase transitions that appear to follow the anticipated hcp ->Sm-type -> dhcp -> distorted fcc sequence of transitions and show the equation of state derived from the x-ray fit data.

Pravica, Michael; Romano, Edward; Quine, Zachary; Pravica, Walter

2006-03-01

342

MBE apparatus for in situ grazing incidence x-ray diffraction  

NASA Astrophysics Data System (ADS)

A molecular beam epitaxy (MBE) apparatus furnished with two E-gun evaporators, two Knudsen cells and RHEED, was built for in situ grazing incidence x-ray diffraction studies. By adopting horizontal sample setting geometry, the entire ultrahigh vacuum chamber was rotated simply with the aid of a spring, and a large sample area was irradiated by the x-rays. Using this apparatus, we observed the 77 superstructure on a Si(111) surface and at a SiO2/Si(111) interface.

Akimoto, K.; Mizuki, J.; Hirosawa, I.; Matsui, J.

1989-07-01

343

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

SciTech Connect

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

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

2007-02-01

344

Femtosecond x-ray line emission from specially designed targets irradiated by short laser pulses  

Microsoft Academic Search

The invention of high-power ultra short pulse lasers has opened way to investigations aimed at creation of a new type of bright x-ray source for different applications including material science and time resolved x-ray diffraction for biology. The conversion efficiency of the laser energy incident onto a solid target into the x-ray emission depends on many factors, including the temporal

Alexander A. Andreev; Hidetoshi Nakano; Jiri Limpouch

2004-01-01

345

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

346

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

SciTech Connect

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

Terwilliger, T.C.; Berendzen, J.

1998-02-25

347

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? 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, S閎astien; Messerschmidt, Marc; Jogl, Gerwald; Dahlberg, Albert E.; Gregory, Steven T.; Bogan, Michael J.

2013-01-01

348

A regularized iterative reconstruction algorithm for x-ray diffraction tomography  

NASA Astrophysics Data System (ADS)

Material discrimination based on conventional or dual energy X-ray computed tomography (CT) imaging can be ambiguous. X-ray diraction imaging (XDI) can be used to construct diraction proles of objects, providing molecular signature information that can be used to characterize the presence of specic materials. Combining X-ray CT and diraction imaging can lead to enhanced detection and identication of explosives in luggage screening. Current XDI scan systems are based on direct imaging rather than tomographic imaging, which require the use of line collimators to localize scattering location and thus result in slow scan performance. In an eort to gain faster scan times and better signal-to-noise ratio, we focus on tomographic inversion techniques for X-ray Diraction Tomography (XDT) and look for joint reconstruction of CT absorption and X-ray diraction prole images of object. We present a fast reconstruction algorithm with geometric feature preserving regularization (IREP) using image-wise based iterative coordinate descent (ICD).We validate the initial results via Monte Carlo simulation of X-ray absorption and coherent scattering in 2 dimensions (2D), and compare the performance of the IREP algorithm with existing inversion techniques such as the ltered backprojection method and the algebraic reconstruction technique. The experimental results show that the IREP method oers improved image quality for enhanced material identication.

Chen, Ke; Casta耋n, David A.

2012-06-01

349

Apparatus for X-ray diffraction microscopy and tomography of cryo specimens  

DOE PAGESBeta

An apparatus for diffraction microscopy of biological and materials science specimens is described. In this system, a coherent soft X-ray beam is selected with a pinhole, and the illuminated specimen is followed by an adjustable beamstop and CCD camera to record diffraction data from non-crystalline specimens. In addition, a Fresnel zone plate can be inserted to allow for direct imaging. The system makes use of a cryogenic specimen holder with cryotransfer capabilities to allow frozen hydrated specimens to be loaded. The specimen can be tilted over a range of +/- 80 degrees for three-dimensional imaging; this is done by computer-controlled motors, enabling automated alignment of the specimen through a tilt series. The system is now in use for experiments in soft X-ray diffraction microscopy.

Beetz, T.; Howells, M.R.; Jacobsen, C.; Kao, C.-C.; Kirz, J.; Lima, E.; Mentes, T.O.; Miao, H.; Sanchez-Hanke, C.; Sayre, D.; Shapiro, D.

2005-06-01

350

Transient x-ray diffraction with simultaneous imaging under high strain-rate loading.  

PubMed

Real time, in situ, multiframe, diffraction, and imaging measurements on bulk samples under high and ultrahigh strain-rate loading are highly desirable for micro- and mesoscale sciences. We present an experimental demonstration of multiframe transient x-ray diffraction (TXD) along with simultaneous imaging under high strain-rate loading at the Advanced Photon Source beamline 32ID. The feasibility study utilizes high strain-rate Hopkinson bar loading on a Mg alloy. The exposure time in TXD is 2-3 ?s, and the frame interval is 26.7-62.5 ?s. Various dynamic deformation mechanisms are revealed by TXD, including lattice expansion or compression, crystal plasticity, grain or lattice rotation, and likely grain refinement, as well as considerable anisotropy in deformation. Dynamic strain fields are mapped via x-ray digital image correlation, and are consistent with the diffraction measurements and loading histories. PMID:25430119

Fan, D; Lu, L; Li, B; Qi, M L; E, J C; Zhao, F; Sun, T; Fezzaa, K; Chen, W; Luo, S N

2014-11-01

351

Apparatus for X-ray diffraction microscopy and tomography of cryo specimens  

SciTech Connect

An apparatus for diffraction microscopy of biological and materials science specimens is described. In this system, a coherent soft X-ray beam is selected with a pinhole, and the illuminated specimen is followed by an adjustable beamstop and CCD camera to record diffraction data from non-crystalline specimens. In addition, a Fresnel zone plate can be inserted to allow for direct imaging. The system makes use of a cryogenic specimen holder with cryotransfer capabilities to allow frozen hydrated specimens to be loaded. The specimen can be tilted over a range of 80 degrees for three-dimensional imaging; this is done by computer-controlled motors, enabling automated alignment of the specimen through a tilt series. The system is now in use for experiments in soft X-ray diffraction microscopy.

Beetz, T. [Stony Brook Univ., Stony Brook, NY (United States); Howells, M. R. [Brookhaven National Laboratory (BNL), Upton, NY (United States). National Synchrotron Light Source; Brookhaven National Laboratory (BNL), Upton, NY (United States). Center for Functional Nanomaterials; Jacobsen, C. [Stony Brook Univ., Stony Brook, NY (United States); Kao, C. -C. [Brookhaven National Laboratory (BNL), Upton, NY (United States). National Synchrotron Light Source; Kirz, J. [Stony Brook Univ., Stony Brook, NY (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source; Lima, E. [Stony Brook Univ., Stony Brook, NY (United States); Mentes, T. O. [Stony Brook Univ., Stony Brook, NY (United States); TASC-INFM National Lab, Trieste (Italy); Miao, H. [Stony Brook Univ., Stony Brook, NY (United States); Sanchez-Hanke, C. [Brookhaven National Laboratory (BNL), Upton, NY (United States). National Synchrotron Light Source; Sayre, D. [Stony Brook Univ., Stony Brook, NY (United States); Shapiro, D. [Stony Brook Univ., Stony Brook, NY (United States)

2005-06-01

352

Transient x-ray diffraction with simultaneous imaging under high strain-rate loading  

NASA Astrophysics Data System (ADS)

Real time, in situ, multiframe, diffraction, and imaging measurements on bulk samples under high and ultrahigh strain-rate loading are highly desirable for micro- and mesoscale sciences. We present an experimental demonstration of multiframe transient x-ray diffraction (TXD) along with simultaneous imaging under high strain-rate loading at the Advanced Photon Source beamline 32ID. The feasibility study utilizes high strain-rate Hopkinson bar loading on a Mg alloy. The exposure time in TXD is 2-3 ?s, and the frame interval is 26.7-62.5 ?s. Various dynamic deformation mechanisms are revealed by TXD, including lattice expansion or compression, crystal plasticity, grain or lattice rotation, and likely grain refinement, as well as considerable anisotropy in deformation. Dynamic strain fields are mapped via x-ray digital image correlation, and are consistent with the diffraction measurements and loading histories.

Fan, D.; Lu, L.; Li, B.; Qi, M. L.; E, J. C.; Zhao, F.; Sun, T.; Fezzaa, K.; Chen, W.; Luo, S. N.

2014-11-01

353

Synchrotron X-Ray Reciprocal Space Mapping, Topography and Diffraction Resolution Studies of Macromolecular Crystal Quality  

NASA Technical Reports Server (NTRS)

A comprehensive study of microgravity and ground grown chicken egg white lysozyme crystals is presented using synchrotron X-ray reciprocal space mapping, topography techniques and diffraction resolution. Microgravity crystals displayed, on average, reduced intrinsic mosaicities but no differences in terms of stress over their earth grown counterparts. Topographic analysis revealed that in the microgravity case the majority of the crystal was contributing to the peak of the reflection at the appropriate Bragg angle. In the earth case at the diffraction peak only a small volume of the crystal contributed to the intensity. The techniques prove to be highly complementary with the reciprocal space mapping providing a quantitative measure of the crystal mosaicity and stress (or variation in lattice spacing) and topography providing a qualitative overall assessment of the crystal in terms of its X-ray diffraction properties. Structural data collection was also carried out both at the synchrotron and in the laboratory.

Boggon, T. J.; Helliwell, J. R.; Judge, Russell A.; Siddons, D. P.; Snell, Edward H.; Stojanoff, V.

2000-01-01

354

High-pressure X-ray diffraction studies of potassium chlorate  

SciTech Connect

Two static high-pressure X-ray diffraction (XRD) studies of potassium chlorate have been performed at pressures of up to {approx}14.3 GPa in a diamond anvil cell at ambient temperature using the 16 ID-B undulator beamline at the Advanced Photon Source for the X-ray source. The first experiment was conducted to ascertain decomposition rates of potassium chlorate as a function of pressure. Below 2 GPa, the sample was observed to decompose rapidly in the presence of the X-ray beam and release oxygen. Above 2 GPa (near the phase I phase II transition), the decomposition rate dramatically slowed so that good quality XRD patterns could be acquired. This suggests a phase-dependent decomposition rate. In the second study, X-ray diffraction spectra were collected at pressures from 2 to 14.3 GPa by aligning virgin portions of the sample into the focused X-ray beam at each pressure. The results suggest the co-existence of mixed monoclinic (I) and rhombohedral (II) phases of potassium chlorate near 2 GPa. At pressures beyond 4 GPa, the XRD patterns show a very good fit to KClO{sub 3} in the rhombohedral phase with space group R3m, in agreement with earlier studies. No further phase transitions were observed with pressure. Decompression of the sample to ambient pressure indicated mixed phases I and II coupled with a small amount of synchrotron X-ray-induced decomposition product. The equation of state within this pressure regime has been determined.

Pravica, Michael; Bai, Ligang; Bhattacharya, Neelanjan (UNLV)

2012-03-15

355

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

356

Determination of line profiles on nano-structured surfaces using EUV and x-ray scattering  

NASA Astrophysics Data System (ADS)

Non-imaging techniques like X-ray scattering are supposed to play an important role in the further development of CD metrology for the semiconductor industry. Grazing Incidence Small Angle X-ray Scattering (GISAXS) provides directly assessable information on structure roughness and long-range periodic perturbations. The disadvantage of the method is the large footprint of the X-ray beam on the sample due to the extremely shallow angle of incidence. This can be overcome by using wavelengths in the extreme ultraviolet (EUV) spectral range, EUV small angle scattering (EUVSAS), which allows for much steeper angles of incidence but preserves the range of momentum transfer that can be observed. Generally, the potentially higher momentum transfer at shorter wavelengths is counterbalanced by decreasing diffraction efficiency. This results in a practical limit of about 10 nm pitch for which it is possible to observe at least the +/- 1st diffraction orders with reasonable efficiency. At the Physikalisch-Technische Bundesanstalt (PTB), the available photon energy range extends from 50 eV up to 10 keV at two adjacent beamlines. PTB commissioned a new versatile Ellipso-Scatterometer which is capable of measuring 6" square substrates in a clean, hydrocarbon-free environment with full flexibility regarding the direction of the incident light polarization. The reconstruction of line profiles using a geometrical model with six free parameters, based on a finite element method (FEM) Maxwell solver and a particle swarm based least-squares optimization yielded consistent results for EUV-SAS and GISAXS. In this contribution we present scatterometry data for line gratings and consistent reconstruction results of the line geometry for EUV-SAS and GISAXS.

Soltwisch, Victor; Wernecke, Jan; Haase, Anton; Probst, J黵gen; Schoengen, Max; Krumrey, Michael; Scholze, Frank; Pomplun, Jan; Burger, Sven

2014-09-01

357

Study on the structure of aqueous potassium chloride solutions using the X-ray diffraction and Raman spectroscopy methods  

NASA Astrophysics Data System (ADS)

Many researchers have studied potassium chloride aqueous solutions, whereas, for the tests were carried out at different conditions, the results with diverse concentrations were not comparable. In this study, the structure of aqueous potassium chloride solutions were determined by X-ray diffraction (both using the synchrotron beam line and laboratory X-ray source) and Raman spectroscopy. Potassium chloride solutions at the concentrations ranging from 0.07% to 26.00% were systematically tested through these methods. For the solutions studied, a semi quantitative structural analysis was performed at the level of the reduced pair distribution functions (RPDFs) deduced from X-ray diffraction diagrams. The structure features can be seen directly from the RPDFs, which show systematic variations with the increase of the solutions. According to the results, when the concentration was above 15.00%, characteristic peak of K+-Cl- contact ion pairs was observed in the RPDFs at 3.15 , and their contributions became more and more significant with the increase of the concentrations. Furthermore, O-H bond lengths in water molecules are stretched with the increase of the concentration. Raman spectroscopy was carried out to support the conclusion that the hydrogen bonds in the aqueous solutions were disrupted with the increase of the potassium chloride concentration.

Li, Fei; Yuan, Junsheng; Li, Dongchan; Li, Shenyu; Han, Zhen

2015-02-01

358

X-Ray Diffraction Study of the Internal Structure of Supercooled Water  

NASA Technical Reports Server (NTRS)

A Bragg X-ray spectrometer equipped with a volume-sensitive Geiger counter and Soller slits and employing filtered molybdenum Ka radiation was used to obtain a set of diffracted intensity curves as a Punction of angle for supercooled water. Diffracted intensity curves in the temperature region of 21 to -16 C were obtained. The minimum between the two main diffraction peaks deepened continuously with lowering temperature, indicating a gradual change in the internal structure of the water. No discontinuity in this trend was noted at the melting point. The internal structure of supercooled water was concluded to become progressively more ice-like as the temperature is lowered.

Dorsch, Robert G.; Boyd, Bemrose

1951-01-01

359

Femtosecond X-ray diffraction maps field-driven charge dynamics in ionic crystals.  

PubMed

X-Ray diffraction provides insight into the distribution of electronic charge in crystals. Equilibrium electron distributions have been determined with high spatial resolution by recording and analysing a large number of diffraction peaks under stationary conditions. In contrast, transient electron densities during and after structure-changing processes are mainly unknown. Recently, we have introduced femtosecond X-ray powder diffraction from polycrystalline samples to determine transient electron density maps with a spatial resolution of 0.03 nm and a temporal resolution of 100 fs. In a pump-probe approach with a laser-driven tabletop hard X-ray source, optically induced structure changes are resolved in time by diffracting the hard X-ray probe pulses at different time delays from the excited powder sample and recording up to several tens of reflections simultaneously. Time-dependent changes of the atomic arrangement in the crystal lattice as well as modified electron densities are derived from the diffraction data. As a prototypical field-driven process, we address here quasi-instantaneous changes of electron density in LiBH(4), LiH and NaBH4 in response to a non-resonant strong optical field. The light-induced charge relocation in LiBH(4) and NaBH(4) exhibits an electron transfer from the anion (BH) to the respective cation. The distorted geometry of the BH4 tetrahedron in LiBH(4) leads to different contributions of the H atoms to electron transfer. LiH displays a charge transfer from Li to H, i.e., an increase of the ionicity of LiH in the presence of the strong electric field. This unexpected behavior originates from strong electron correlations in LiH as is evident from a comparison with quasi-particle bandstructures calculated within the Coulomb-hole-plus-screened-exchange (COHSEX) formalism. PMID:25415431

Woerner, Michael; Holtz, Marcel; Juv, Vincent; Elsaesser, Thomas; Borgschulte, Andreas

2014-01-01

360

X-ray diffraction study of laser deposited high T/sub c/ thin films on (001) SrTiO/sub 3/  

SciTech Connect

We present a detailed x-ray diffraction structural study of a YBa/sub 2/Cu/sub 3/O/sub 7-x/ superconducting film, deposited by a pulsed laser technique on (001) SrTiO/sub 3/. The film was found to be polycrystalline with c-axis preferential orientation normal to the substrate plane. We have also performed in-plane diffraction experiments where we find that these grains are aligned along the substrate crystallographic axes in the plane in the film. From the x-ray line widths, we observe residual strain broadening which we attribute to macroscopic compositional inhomogeneity.

Miceli, P.F.; Venkatesan, T.; Wu, X.D.; Potenza, J.A.

1988-02-25

361

The structure of actin-rich filaments of muscles according to x-ray diffraction.  

PubMed

From analysis of moderate- to small-angle x-ray diffraction patterns, in the light of similar experience with paramyosin, has been derived the following description for the structure of actin-rich filaments in "tinted" portions of the adductor muscle of the clam, Venus mercenaria: 1. Some 11 diffraction maxima, widely streaked along layer lines and occurring at moderate diffraction angles (spacings 7 to 60 A) appear to be accounted for as (hk) reflections of a net whose cell elements are, for dry material: a =... 82 A, b = 406 A (filament axis identity period), and gamma =... 82 degrees (angle between a and b axes). These reflections follow a selection rule which indicates that the net cell is non-primitive and contains 15 equivalent locations (nodes) arranged as shown in Fig. 5. An alternative net has b' = 351 A and 13 nodes per cell. 2. Another interpretation rolls the net into a large-scale helix and places the 15 (or 13) nodes along 7 (or 6) turns of a helical locus projecting 406 (or 351) A along the filament axis. Whether considered to be built of planar-net or helix-net cells, the individual filament contains a single cell width transverse to its axis. Transverse filament dimensions are, therefore, in either case similar (50 to 100 A). 3. Consideration of existing electron-optical, physicochemical, and x-ray diffraction data regarding isolated actin suggests that the net cell is built of rods, each containing in cross-section from one to four actin molecules which run parallel to or twisted about rod axes that extend at 12 degrees to the filament axis along the (21) diagonals of the cell. Depending on monomer shape, 2 to 15 monomers furnish length to reach across two cells, and the actin molecules are built into each rod in such a way as to repeat (or nearly repeat) structure 15 (or 13) times along the double cell length. Further details of intra-rod structure cannot be suggested because of lack of wide-angle diffraction information. 4. The actin system is sensitive to treatment of the muscle with ethanol. Concentrations of 5 per cent or greater abolish the net reflections. Other solvents-water, benzene, ether, pyridine, acetone-do not alter the pattern materially. 5. Two other reflections, occurring at the first and second layer lines of an axial periodicity of about 400 A, do not clearly belong to the actin-net system. They represent either a superstructure built upon the filaments by parts of the actin molecules themselves or by incorporated other molecular species, or they arise from an additional macromolecular component (possibly myosin, or its homologues or fractions) of similar axial periodicity. PMID:13295312

SELBY, C C; BEAR, R S

1956-01-25

362

X-ray Diffraction Studies of the Thick Filament in Permeabilized Myocardium from Rabbit  

SciTech Connect

Low angle x-ray diffraction patterns from relaxed permeabilized rabbit cardiac trabeculae and psoas muscle fibers were compared. Temperature was varied from 25{sup o}C to 5{sup o}C at 200 mM and 50 mM ionic strengths ({mu}), respectively. Effects of temperature and {mu} on the intensities of the myosin layer lines (MLL), the equatorial intensity ratio I{sub 1,1}/I{sub 1,0}, and the spacing of the filament lattice are similar in both muscles. At 25{sup o}C, particularly at {mu} = 50 mM, the x-ray patterns exhibited up to six orders of MLL and sharp meridional reflections, signifying that myosin heads (cross-bridges) are distributed in a well-ordered helical array. Decreasing temperature reduced MLL intensities but increased I{sub 1,1}/I{sub 1,0}. Decreases in the MLL intensities indicate increasing disorder in the distribution of cross-bridges on the thick filaments surface. In the skeletal muscle, order/disorder is directly correlated with the hydrolysis equilibrium of ATP by myosin, [M.ADP.P{sub i}]/[M.ATP]. Similar effects of temperature on MLL and similar biochemical ATP hydrolysis pathway found in both types of muscles suggest that the order/disorder states of cardiac cross-bridges may well be correlated with the same biochemical and structural states. This implies that in relaxed cardiac muscle under physiological conditions, the unattached cross-bridges are largely in the M.ADP.P{sub i} state and with the lowering of the temperature, the equilibrium is increasingly in favor of [M.ATP] and [A.M.ATP]. There appear to be some differences in the diffraction patterns from the two muscles, however. Mainly, in the cardiac muscle, the MLL are weaker, the I{sub 1,1}/I{sub 1,0} ratio tends to be higher, and the lattice spacing D{sub 10}, larger. These differences are consistent with the idea that under a wide range of conditions, a greater fraction of cross-bridges is weakly bound to actin in the myocardium.

Xu,S.; Martyn, D.; Zaman, J.; Yu, L.

2007-01-01

363

X-ray Diffraction Studies of the Thick Filament in Permeabilized Myocardium from Rabbit  

SciTech Connect

Low angle x-ray diffraction patterns from relaxed permeabilized rabbit cardiac trabeculae and psoas muscle fibers were compared. Temperature was varied from 25{sup o}C to 5{sup o}C at 200 mM and 50 mM ionic strengths ({mu}), respectively. Effects of temperature and {mu} on the intensities of the myosin layer lines (MLL), the equatorial intensity ratio I{sub 1,1}/I{sub 1,0}, and the spacing of the filament lattice are similar in both muscles. At 25{sup o}C, particularly at {mu} = 50 mM, the x-ray patterns exhibited up to six orders of MLL and sharp meridional reflections, signifying that myosin heads (cross-bridges) are distributed in a well-ordered helical array. Decreasing temperature reduced MLL intensities but increased I{sub 1,1}/I{sub 1,0}. Decreases in the MLL intensities indicate increasing disorder in the distribution of cross-bridges on the thick filaments surface. In the skeletal muscle, order/disorder is directly correlated with the hydrolysis equilibrium of ATP by myosin, [M.ADP.P{sub i}]/[M.ATP]. Similar effects of temperature on MLL and similar biochemical ATP hydrolysis pathway found in both types of muscles suggest that the order/disorder states of cardiac cross-bridges may well be correlated with the same biochemical and structural states. This implies that in relaxed cardiac muscle under physiological conditions, the unattached cross-bridges are largely in the M.ADP.P{sub i} state and with the lowering of the temperature, the equilibrium is increasingly in favor of [M.ATP] and [A.M.ATP]. There appear to be some differences in the diffraction patterns from the two muscles, however. Mainly, in the cardiac muscle, the MLL are weaker, the I{sub 1,1}/I{sub 1,0} ratio tends to be higher, and the lattice spacing D{sub 10}, larger. These differences are consistent with the idea that under a wide range of conditions, a greater fraction of cross-bridges is weakly bound to actin in the myocardium.

Xu,S.; Martyn, D.; Zaman, J.; Yu, L.

2006-01-01

364

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

SciTech Connect

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, E-mail: xiahuang@aps.anl.gov; Gog, Thomas; Assoufid, Lahsen [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Peng, Ru-Wen, E-mail: rwpeng@nju.edu.cn [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Siddons, D. P. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2014-11-03

365

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

366

X-ray diffraction imaging of metal-oxide epitaxial tunnel junctions made by optical lithography: use of focused and unfocused X-ray beams.  

PubMed

X-ray diffraction techniques are used in imaging mode in order to characterize micrometre-sized objects. The samples used as models are metal-oxide tunnel junctions made by optical lithography, with lateral sizes ranging from 150 祄 down to 10 祄 and various shapes: discs, squares and rectangles. Two approaches are described and compared, both using diffraction contrast: full-field imaging (topography) and raster imaging (scanning probe) using a micrometre-sized focused X-ray beam. It is shown that the full-field image gives access to macroscopic distortions (e.g. sample bending), while the local distortions, at the micrometre scale (e.g. tilts of the crystalline planes in the vicinity of the junction edges), can be accurately characterized only using focused X-ray beams. These local defects are dependent on the junction shape and larger by one order of magnitude than the macroscopic curvature of the sample. PMID:23412494

Mocuta, Cristian; Barbier, Antoine; Stanescu, Stefan; Matzen, Sylvia; Moussy, Jean Baptiste; Ziegler, Eric

2013-03-01

367

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

368

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

NASA Astrophysics Data System (ADS)

The linear 1-alcohols n-C16H33OH , n-C17H35OH , n-C19H39OH have been imbibed and solidified in lined up, tubular mesopores of silicon with 10 and 15 nm mean diameters, respectively. X-ray diffraction measurements reveal a set of six discrete orientation states (揹omains) characterized by a perpendicular alignment of the molecules with respect to the long axis of the pores and by a fourfold 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 nanoscale version of the Bridgman technique of single-crystal growth, where the dominant growth direction is aligned parallel to the long pore axes. Our observations are analogous to the growth phenomenology encountered for medium length n -alkanes confined in mesoporous silicon [A. Henschel, T. Hofmann, P. Huber, and K. Knorr, 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.

Henschel, Anke; Huber, Patrick; Knorr, Klaus

2008-04-01

369

On screening for Special Nuclear Materials (SNMs) with X-ray diffraction  

NASA Astrophysics Data System (ADS)

A novel detection technique employing X-ray diffraction (XRD) to screen for Special Nuclear Materials (SNMs), in particular for uranium, has been recently proposed. It is based on the interesting fact that uranium (and incidentally, plutonium) has a non-cubic lattice structure, in contrast to all other non-SNM, high-density elements of the Periodic Table. The principle of this screening technique is briefly elucidated by comparing the XRD lines of uranium with those of lead, a material of high atomic number ( Z) commonly found in container traffic. Several physical conditions that must be satisfied to enable XRD for SNM screening are considered. To achieve adequate penetration, both of suspicious high- Z materials and their containers, photon energies of 1 MeV and above must be employed. Implications from partial coherence theory for the XRD measurement geometry at such photon energies are presented. The question of multiple scatter degradation of the coherent scatter signal is addressed. Technological considerations relevant to performing XRD at 1 MeV, particularly regarding the radiation source and detector, are discussed. A novel secondary aperture scheme permitting high energy XRD is presented. It is concluded that the importance of the application and the prospect of its feasibility are sufficient to warrant experimental verification.

Harding, G.

2010-05-01

370

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

371

X-ray and neutron diffraction study of nanocrystalline Ti-Ru-Fe-O compounds  

SciTech Connect

The effect of adding oxygen on the structure of nanocrystalline Ti-Ru-Fe compounds obtained by high-energy ball-milling has been studied by X-ray and neutron diffraction using a Rietveld refinement analysis. It is shown that oxygen atoms readily oxidize Ti to form various types of titanium oxides depending on the oxygen content. In each case, a simple cubic structure (cP2-CsCl) is also formed during milling but with a concentration higher than expected on the basis of various reaction schemes. Through a detailed analysis of the neutron and X-ray diffraction peaks, it is shown that the 1a site of the CsCl-type unit cell is depleted from Ti atoms by preferential substitution with Fe. At high oxygen concentration, the alloy is a multiphase material containing Ti{sub 2{minus}x}Ru{sub 1+y}Fe{sub 1+z}, Ti oxides, Ru, and Fe.

Blouin, M.; Guay, D. [INRS-Energie et Materiaux, Varennes, Quebec (Canada)] [INRS-Energie et Materiaux, Varennes, Quebec (Canada); Huot, J.; Schulz, R. [Inst. de recherche d`Hydro-Quebec, Varennes, Quebec (Canada). Technologies Emergentes de Production et de Stockage] [Inst. de recherche d`Hydro-Quebec, Varennes, Quebec (Canada). Technologies Emergentes de Production et de Stockage; Swainson, I.P. [National Research Council, Chalk River, Ontario (Canada). Chalk River Labs.] [National Research Council, Chalk River, Ontario (Canada). Chalk River Labs.

1998-11-01

372

Determination of volume fraction in multiphase systems using incomplete pole figures. [X ray diffraction metallography  

NASA Technical Reports Server (NTRS)

The determination of the volume fraction of a second phase in a multiphase sample by X-ray diffraction becomes more difficult if the diffracting planes have a preferred orientation. Lopata and Kula have described a method of treating this problem using complete pole figures for each of the phases. With some samples, it is not always possible or convenient to obtain data over the full hemisphere. Equations and an example are given which require X-ray data over a limited range of approximately 0 to 75 deg. This can be obtained by reflection without a specially cut sample or transmission data. A series of Legendre polynomials are fitted to data collected while spinning the sample about its normal. An extrapolation is made possible by introducing two conditions on the end points which must be satisfied if the extrapolation functions are to be valid.

Houska, C. R.; Rao, V.

1978-01-01

373

Edge diffraction effect at the refraction of X rays in a diamond prism  

NASA Astrophysics Data System (ADS)

The refraction of monochromatic X-ray radiation in an optically polished diamond prism has been studied. Measurements have been performed on the ID10 channel of the ESRF synchrotron (Grenoble). It has been found that parabolic geometric deviations of the profile of the refractive face of the prism from a plane are responsible for the interference pattern that is similar in the structure of oscillations to an edge diffraction effect. As a result, a diffraction pattern characteristic of the near-field Fresnel zone can be observed in the farfield zone. A high sensitivity to phase perturbations ensures the possibility of using this effect to analyze the parameters of an X-ray wavefront with a dimension of about 1 ?m.

Tur'yanskii, A. G.; Konovalov, O. V.; Gizha, S. S.; Beilin, N. D.

2014-12-01

374

Profiling of Fiber Texture Gradients by Anomalous X-ray Diffraction  

NASA Astrophysics Data System (ADS)

Preferred crystallographic orientation or texture is a typically observed phenomenon in polycrystalline thin films. In addition, texture was revealed in numerous x-ray diffraction studies to increase with layer thickness. The phenomenon is rather significant for the optimized preparation of thin films, but was difficult to measure so far. A method is presented that allows for texture profiling by exploiting the anomalous variation of the x-ray attenuation coefficient in the vicinity of an elemental absorption edge. The study reports the application of the technique to thin ZnO:Al films by measuring with wavelengths below and above the Zn K edge. Large texture gradients between 0.03 and 0.3 mrd/nm were revealed to arise in these samples. Anomalous diffraction is concluded to enable the determination of texture gradients as required in many thin film projects.

Birkholz, M.; Darowski, N.; Zizak, I.

375

Method for characterizing mask defects using image reconstruction from X-ray diffraction patterns  

DOEpatents

The invention applies techniques for image reconstruction from X-ray diffraction patterns on the three-dimensional imaging of defects in EUVL multilayer films. The reconstructed image gives information about the out-of-plane position and the diffraction strength of the defect. The positional information can be used to select the correct defect repair technique. This invention enables the fabrication of defect-free (since repaired) X-ray Mo--Si multilayer mirrors. Repairing Mo--Si multilayer-film defects on mask blanks is a key for the commercial success of EUVL. It is known that particles are added to the Mo--Si multilayer film during the fabrication process. There is a large effort to reduce this contamination, but results are not sufficient, and defects continue to be a major mask yield limiter. All suggested repair strategies need to know the out-of-plane position of the defects in the multilayer.

Hau-Riege, Stefan Peter (Fremont, CA)

2007-05-01

376

Time-resolved x-ray diffraction studies of the sarcoplasmic reticulum membrane during active transport.  

PubMed

X-ray and neutron diffraction studies of oriented multilayers of a highly purified fraction of isolated sarcoplasmic reticulum (SR) have previously provided the separate profile structures of the lipid bilayer and the Ca2+-ATPase molecule within the membrane profile to approximately 10-A resolution. These studies used biosynthetically deuterated SR phospholipids incorporated isomorphously into the isolated SR membranes via phospholipid transfer proteins. Time-resolved x-ray diffraction studies of these oriented SR membrane multilayers have detected significant changes in the membrane profile structure associated with phosphorylation of the Ca2+-ATPase within a single turnover of the Ca2+-transport cycle. These studies used the flash photolysis of caged ATP to effectively synchronize the ensemble of Ca2+-ATPase molecules in the multilayer, synchrotron x-radiation to provide 100-500-ms data collection times, and double-beam spectrophotometry to monitor the Ca2+-transport process directly in the oriented SR membrane multilayer. PMID:3160394

Blasie, J K; Herbette, L G; Pascolini, D; Skita, V; Pierce, D H; Scarpa, A

1985-07-01

377

Single-crystal X-ray diffraction studies on structural transformations of porous coordination polymers.  

PubMed

X-Ray single-crystal diffraction has been the most straightforward and important technique in structural determination of crystalline materials for understanding their structure-property relationships. This powerful tool can be used to directly visualize the precise and detailed structural information of porous coordination polymers or metal-organic frameworks at different states, which are unique for their flexible host frameworks compared with conventional adsorbents. With a series of selected recent examples, this review gives a brief overview of single-crystal X-ray diffraction studies and single-crystal to single-crystal transformations of porous coordination polymers under various chemical and physical stimuli such as solvent and gas sorption/desorption/exchange, chemical reaction and temperature change. PMID:24971601

Zhang, Jie-Peng; Liao, Pei-Qin; Zhou, Hao-Long; Lin, Rui-Biao; Chen, Xiao-Ming

2014-08-21

378

Structural investigation of GaInP nanowires using X-ray diffraction  

PubMed Central

In this work the structure of ternary GaxIn1?爔P nanowires is investigated with respect to the chemical composition and homogeneity. The nanowires were grown by metal杘rganic vapor-phase epitaxy. For the investigation of ensemble fluctuations on several lateral length scales, X-ray diffraction reciprocal space maps have been analyzed. The data reveal a complicated varying materials composition across the sample and in the nanowires on the order of 20%. The use of modern synchrotron sources, where beam-sizes in the order of several 10?m are available, enables us to investigate compositional gradients along the sample by recording diffraction patterns at different positions. In addition, compositional variations were found also within single nanowires in X-ray energy dispersive spectroscopy measurements. PMID:24089580

Kriegner, D.; Persson, J.M.; Etzelstorfer, T.; Jacobsson, D.; Wallentin, J.; Wagner, J.B.; Deppert, K.; Borgstr鰉, M.T.; Stangl, J.

2013-01-01

379

Study of X-ray Weakness among Luminous Narrow-line Quasars  

NASA Astrophysics Data System (ADS)

The unusual properties of Narrow-line Seyfert 1 galaxies (NLS1s) are thought to result from a higher accretion rate relative to Eddington than broad-line Seyferts. Luminous NLS1s should have the highest accretion rates of all. With our recent study, several X-ray weak objects were found, and it is suggested that X-ray weakness may occur more frequently among more luminous regime. To investigate the nature of X-ray weak objects, we propose XMM-Newton observations of five optically-luminous X-ray--weak NLS1s.

Matsumoto, Chiho

2005-10-01

380

Residual stress analysis in aged graphite\\/PMR15 composites using X-ray diffraction  

Microsoft Academic Search

In this paper, we present and discuss the methodology to monitor average residual stresses in aged high temperature unidirectional and woven graphite fiber\\/PMR-15 composites. The aging experiments were performed at 315癈 for 1170h in nitrogen and 1064h in air, respectively. The proposed methodology was based on X-ray diffraction (XRD) strain measurements in embedded crystalline metallic inclusions. The aging experiments performed

B. Benedikt; M. Lewis; P. Rangaswamy; M. Kumosa; P. Predecki; L. Kumosa; M. Gentz

2006-01-01

381

Planar techniques for fabricating X-ray diffraction gratings and zone plates  

NASA Technical Reports Server (NTRS)

The state of current planar techniques in the fabrication of Fresnel zone plates and diffraction gratings is reviewed. Among the fabrication techniques described are multilayer resist techniques; scanning electron beam lithography; and holographic lithography. Consideration is also given to: X-ray lithography; ion beam lithography; and electroplating. SEM photographs of the undercut profiles obtained in a type AZ 135OB photoresistor by holographic lithography are provided.

Smith, H. I.; Anderson, E. H.; Hawryluk, A. M.; Schattenburg, M. L.

1984-01-01

382

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

383

A study of phase transitions in lead difluoride by use of polychromatic X-ray diffraction  

NASA Technical Reports Server (NTRS)

A polychromatic X-ray diffraction technique was used to obtain patterns of alpha-PbF2 and beta-PbF2. The results obtained at room temperature and 314 C at 1 atm, and at room temperature at 5.5 kbar, are in good agreement with published data. The advantages of the technique for high-temperature and high-pressure work are discussed.

Mahajan, V. K.; Chang, P. T.; Margrave, J. L.

1975-01-01

384

PICOSECOND X-RAY DIFFRACTION FROM LASER-SHOCKED COPPER AND IRON  

E-print Network

PICOSECOND X-RAY DIFFRACTION FROM LASER-SHOCKED COPPER AND IRON J.S. Wark, J.F. Belak, G.W. Collins, J.D. Colvin, H.M. Davies, M. Duchaineau, J.H. Eggert, T.C. Germann, J. Hawreliak, A. Higginbotham, B Compression of Condensed Matter - 2005, edited by M. D. Furnish, M. Elert, T. P. Russell, and C. T. White

Meyers, Marc A.

385

DMSO produces a new subgel phase in DPPC: DSC and X-ray diffraction study  

Microsoft Academic Search

Equilibrium phases and the kinetics of subgel phase transformation of dipalmitoylphosphatidylcholine (DPPC) hydrated with mixtures of dimethylsulfoxide (DMSO)\\/water have been studied using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The rate of gel-to-subgel transformation is decreased with a small increase in X, the DMSO\\/water mole fraction, but then speeds up and becomes faster than in pure water by X

Stephanie Tristram-Nagle; Tisha Moore; Horia I. Petrache; John F. Nagle

1998-01-01

386

Guest Editor's introduction: Special issue on high resolution x-ray diffraction and topography  

Microsoft Academic Search

The 5th Biennial Conference on High Resolution X-ray Diffraction and Topography (XTOP2000) was held in Ustron-Jaszowiec, Poland from 13-15 September 2000. It was organised jointly by the Institute of Experimental Physics of University of Warsaw and the Institute of Physics of Polish Academy of Sciences (PAS) in Warsaw, and a couple of colleagues from several other scientific institutions in Poland

J. Gronkowski

2001-01-01

387

Estimation of Clay Proportions in Mixtures by X-Ray Diffraction and Computerized Chemical Mass Balance  

Microsoft Academic Search

As part of a laboratory study of the hydrothermal alteration of kimberlite, a mass balance procedure has been developed for estimating the relative proportions of synthetic phyllosilicate phases-- chlorite, vermiculite, smectite, kaolinite and serpentine--present in reaction products. The procedure is based on a combination of X-ray powder diffraction (XRD) measurements (for phase identification), atomic absorption determinations (for total Si, A1,

Mark Hodgson; A. WILLIAM L. DUDENEY

1984-01-01

388

Apparatus for High-Pressure High-Temperature X-Ray Powder Diffraction Studies  

Microsoft Academic Search

A high-pressure high-temperature x-ray powder diffraction apparatus has been developed based on a modification of the belt apparatus, which is an internally heated compressible gasket device. The unique feature of this device is that the die-support ring assembly is fabricated in two parts which mate along a plane normal to the piston axis. The split-die design permits entry of the

P. J. Freud; C. B. Sclar

1969-01-01

389

High-pressure phases of plutonium monoselenide studied by X-ray diffraction  

Microsoft Academic Search

Plutonium monoselenide was studied under high pressure up to 47 GPa, at room temperature, using a diamond anvil cell in an energy dispersive X-ray diffraction facility. At ambient pressure, PuSe has the NaC1-type (B1) structure. The compound has been found to undergo a second-order crystallographic phase transition at around 20 GPa. This phase can be described as a distorted B1

M. Gensini; E. Gering; S. Heathman; U. Benedict; J. C. Spirlet

1990-01-01

390

X-ray diffraction study of ?-stabilized plutonium alloys under pressure  

Microsoft Academic Search

Previous extensive studies of the ????-phase transformation induced by temperature and\\/or by pressure in ?-stabilized plutonium alloys indicate strong dependence on parameters such as solute type, solute distribution, chemical impurities, kinetics, thermodynamic path.The present paper reports results obtained on two Pu2.3at.%Ga binary alloys differing by solute homogenization treatment and studied under pressure by in situ by X-ray diffraction in diamond

Ph Faure; C. Genestier

2010-01-01

391

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

392

Spin Density Wave Dislocation in Chromium Probed by Coherent X-ray Diffraction  

SciTech Connect

We report on the study of a magnetic dislocation in pure chromium. Coherent X-ray diffraction profiles obtained on the incommensurate Spin Density Wave (SDW) reflection are consistent with the presence of a dislocation of the magnetic order, embedded at a few micrometers from the surface of the sample. Beyond the specific case of magnetic dislocations in chromium, this work may open up a new method for the study of magnetic defects embedded in the bulk.

Wilkins, S.B.; Jacques, V.L.R.; Le Bolloc抙, D.; Ravy, S.; Giles, C.; Livet, F.

2009-08-19

393

Kapitza conductance of Bi\\/Sapphire interface measured by time-resolved x-ray diffraction  

Microsoft Academic Search

We measure the thermal boundary (Kapitza) conductance at the interface between single crystal thin films of bismuth and sapphire using time-resolved x-ray diffraction. Films of varying thickness (65-284 nm) are grown by molecular beam epitaxy with their c-axis perpendicular to the surface. In the measurements, an ultrafast laser pulse is used to rapidly heat the near-surface region of the film,

Yu-Miin Sheu; Yi-Jiunn Chien; Ctirad Uher; Mariano Trigo; Jian Chen; Shambhu Ghimire; Donald Walko; Emily Peterson; Dohn Arms; Eric Landahl; David Reis

2010-01-01

394

PREFACE: XTOP 2004 -- 7th Biennial Conference on High Resolution X-Ray Diffraction and Imaging  

Microsoft Academic Search

The 7th Biennial Conference on High Resolution X-Ray Diffraction and Imaging (XTOP 2004) was held in the Prague suburb of Pruhonice, Czech Republic, during 7-10 September 2004. It was organized by the Czech and Slovak Crystallographic Association in cooperation with the Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Masaryk University, Brno, and Charles University, Prague. XTOP

Vaclav Hol

2005-01-01

395

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

SciTech Connect

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

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

2013-12-15

396

Diaplectic labradorite glass from the manicouagan impact crater: II. X-ray diffraction studies and structural model  

Microsoft Academic Search

The structural state of diaplectic labradorite glass (?An58) from the Manicouagan impact crater and of its fusion-formed glass analog have been investigated by X-ray diffraction studies.\\u000a The experimental X-ray intensity distribution patterns indicate that the diaplectic and fusion-formed glasses are structurally\\u000a rather similar, the former being apparently slightly less disordered. Theoretical X-ray distribution curves have been calculated\\u000a using the structure

E. Diemann; J. Arndt

1984-01-01

397

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

398

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

E-print Network

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 10^13 W/cm^2 pulse, containing 10^12 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; Benner, W H; Bergh, M; Bogan, M J; Bostedt, C; Boutet, S; Burmeister, F; Caleman, C; D黶terer, S; Frank, M; Hajdu, J; Hau-Riege, S P; Hodgson, K O; Hoener, M; Huldt, G; Kuhlmann, M; Lee, R W; London, R A; Maia, F R N C; Marchesini, S; M鰈ler, T; Plonjes, E; Schneider, J R; Seibert, M M; Shapiro, D A; Spiller, E; Szoke, A; Timneanu, N; Treusch, R; Tschentscher, T; Van der Spoel, D; Woods, B W; Bajt, Sasa; Barty, Anton; Bergh, Magnus; Bogan, Michael J.; Bostedt, Christoph; Boutet, Sebastien; Burmeister, Florian; Caleman, Carl; Chapman, Henry N.; Dusterer, Stefan; Frank, Matthias; Hajdu, Janos; Hau-Riege, Stefan P.; Hodgson, Keith O.; Hoener, Matthias; Huldt, Gosta; Kuhlmann, Marion; Lee, Richard W.; London, Richard A.; Maia, Filipe R.N.C.; Marchesini, Stefano; Moller, Thomas; Plonjes, Elke; Schneider, Jochen R.; Shapiro, David A.; Spiller, Eberhard; Spoel, David van der; Szoke, Abraham; Timneanu, Nicusor; Treusch, Rolf; Tschentscher, Thomas; Woods, Bruce W.

2006-01-01

399

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

400

Time-resolved x-ray diffraction techniques for bulk polycrystalline materials under dynamic loading  

SciTech Connect

We have developed two techniques for time-resolved x-ray diffraction from bulk polycrystalline materials during dynamic loading. In the first technique, we synchronize a fast detector with loading of samples at strain rates of ?10{sup 3}10{sup 4} s{sup ?1} in a compression Kolsky bar (split Hopkinson pressure bar) apparatus to obtain in situ diffraction patterns with exposures as short as 70 ns. This approach employs moderate x-ray energies (1020 keV) and is well suited to weakly absorbing materials such as magnesium alloys. The second technique is useful for more strongly absorbing materials, and uses high-energy x-rays (86 keV) and a fast shutter synchronized with the Kolsky bar to produce short (?40??s) pulses timed with the arrival of the strain pulse at the specimen, recording the diffraction pattern on a large-format amorphous silicon detector. For both techniques we present sample data demonstrating the ability of these techniques to characterize elastic strains and polycrystalline texture as a function of time during high-rate deformation.

Lambert, P. K.; Hustedt, C. J.; Zhao, M.; Ananiadis, A. G.; Hufnagel, T. C. [Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Vecchio, K. S. [Department of NanoEngineering, University of California San Diego, La Jolla, California 92093 (United States); Huskins, E. L. [Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37830 (United States); US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland 21005 (United States); Casem, D. T. [US Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, Maryland 21005 (United States); Gruner, S. M. [Department of Physics, Cornell University, Ithaca, New York 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853 (United States); Tate, M. W.; Philipp, H. T.; Purohit, P.; Weiss, J. T. [Department of Physics, Cornell University, Ithaca, New York 14853 (United States); Woll, A. R. [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, New York 14853 (United States); Kannan, V.; Ramesh, K. T. [Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Kenesei, P.; Okasinski, J. S.; Almer, J. [X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2014-09-15

401

X-ray structure of perdeuterated diisopropyl fluorophosphatase (DFPase): perdeuteration of proteins for neutron diffraction  

PubMed Central

The signal-to-noise ratio is one of the limiting factors in neutron macromolecular crystallography. Protein perdeuteration, which replaces all H atoms with deuterium, is a method of improving the signal-to-noise ratio of neutron crystallography experiments by reducing the incoherent scattering of the hydrogen isotope. Detailed analyses of perdeuterated and hydrogenated structures are necessary in order to evaluate the utility of perdeuterated crystals for neutron diffraction studies. The room-temperature X-ray structure of perdeuterated diisopropyl fluorophosphatase (DFPase) is reported at 2.1? resolution. Comparison with an independently refined hydrogenated room-temperature structure of DFPase revealed no major systematic differences, although the crystals of perdeuterated DFPase did not diffract neutrons. The lack of diffraction is examined with respect to data-collection and crystallo璯raphic parameters. The diffraction characteristics of successful neutron structure determinations are presented as a guideline for future neutron diffraction studies of macromolecules. X-ray diffraction to beyond 2.0? resolution appears to be a strong predictor of successful neutron structures. PMID:20383004

Blum, Marc-Michael; Tomanicek, Stephen J.; John, Harald; Hanson, B. Leif; R黷erjans, Heinz; Schoenborn, Benno P.; Langan, Paul; Chen, Julian C.-H.

2010-01-01

402

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

403

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

PubMed

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. PMID:23278003

Gupta, Y M; Turneaure, Stefan J; Perkins, K; Zimmerman, K; Arganbright, N; Shen, G; Chow, P

2012-12-01

404

Mouse blood vessel imaging by in-line x-ray phase-contrast imaging  

Microsoft Academic Search

It is virtually impossible to observe blood vessels by conventional x-ray imaging techniques without using contrast agents. In addition, such x-ray systems are typically incapable of detecting vessels with diameters less than 200 祄. Here we show that vessels as small as 30 祄 could be detected using in-line phase-contrast x-ray imaging without the use of contrast agents. Image quality

Xi Zhang; Xiao-Song Liu; Xin-Rong Yang; Shao-Liang Chen; Pei-Ping Zhu; Qing-Xi Yuan

2008-01-01

405

Portable apparatus for in situ x-ray diffraction and fluorescence analyses of artworks.  

PubMed

A portable X-ray fluorescence/X-ray diffraction (XRF/XRD) system for artwork studies has been designed constructed and tested. It is based on Debye Scherrer XRD in reflection that takes advantage of many recent improvements in the handling of X-rays (polycapillary optics; advanced two-dimensional detection). The apparatus is based on a copper anode air cooled X-ray source, and the XRD analysis is performed on a 5-20 ?m thick layer from the object surface. Energy dispersive XRF elemental analysis can be performed at the same point as XRD, giving elemental compositions that support the interpretation of XRD diagrams. XRF and XRD analyses were tested to explore the quality and the limits of the analytical technique. The XRD diagrams are comparable in quality with diagrams obtained with conventional laboratory equipment. The mineral identification of materials in artwork is routinely performed with the portable XRF-XRD system. Examples are given for ceramic glazes containing crystals and for paintings where the determination of pigments is still a challenge for nondestructive analysis. For instance, lead compounds that provide a variety of color pigments can be easily identified as well as a pigment such as lapis lazuli that is difficult to identify by XRF alone. More than 70 works of art have been studied in situ in museums, monuments, etc. In addition to ceramics and paintings, these works include bronzes, manuscripts, etc., which permit improvement in the comprehension of ancient artistic techniques. PMID:21615981

Eveno, Myriam; Moignard, Brice; Castaing, Jacques

2011-10-01

406

A SEARCH FOR IRON EMISSION LINES IN THE CHANDRA X-RAY SPECTRA OF NEUTRON STAR LOW-MASS X-RAY BINARIES  

E-print Network

While iron emission lines are well studied in black hole systems, both in X-ray binaries and active galactic nuclei, there has been less of a focus on these lines in neutron star low-mass X-ray binaries (LMXBs). However, ...

Cackett, E. M.

407

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

408

X-ray diffraction from high pressure Ge using synchrotron radiation  

NASA Technical Reports Server (NTRS)

The high pressure structural phase transition in Ge has been studied using the energy dispersive X-ray diffraction technique and a synchrotron radiation source. Ge was observed to transform to the beta-Sn tetragonal structure in agreement with the earlier results of Jamieson, but the phase transition began at 80 + or - 5 kilobars, a somewhat lower value than generally reported. These experimental diffraction results are compared with the recent self-consistent pseudopotential calculations of Yin and Cohen (1981) and with the observed transition pressure for shock wave loaded Ge.

Baublitz, M., Jr.; Ruoff, A. L.

1982-01-01

409

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; Sch黮ein, Florian J. R.; Krenner, Hubert J.; Wixforth, Achim; Salditt, Tim

2014-01-01

410

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

411

X-ray diffraction and absorption studies of ion exchanged glasses  

NASA Astrophysics Data System (ADS)

X-ray diffraction and absorption experiments were performed to determine the structure of commercial sodium silicate glasses before and after a silver-sodium ion exchange. EXAFS measurements at the Na and Ag K-edge display the transition of the sodium environment consisting of five oxygens analogously to that of disilicate glasses to the twofold coordination of silver similar to crystalline Ag 2O. The existence of Ag?Ag correlations could be deduced from both the curve-fitting analyses of Ag K-edge oscillations and the differential distribution function of diffraction data. The influence of silver incorporation on the silicate network structure has been shown.

Dubiel, M.; Schmitz, R.; Kolb, U.; Gutwerk, D.; Bertagnolli, H.

1995-02-01

412

X-Ray Diffraction and Nuclear Quadrupole Resonance Studies of Chromium Trichloride  

Microsoft Academic Search

The infinite-layer compound CrCl3 is found to undergo a first-order phase transformation near 240癒. The crystal structures of the high- and low-temperature phases have been elucidated by detailed x-ray diffraction and 35Cl nuclear quadrupole resonance studies. The previously reported structure for CrCl3 is shown to be incorrect. The present single-crystal diffraction results at 298 and 225癒 give monoclinic (C2\\/m: a0=5.959

Bruno Morosin; Albert Narath

1964-01-01

413

Disentangling atomic-layer-specific x-ray absorption spectra by Auger electron diffraction spectroscopy  

NASA Astrophysics Data System (ADS)

In order to investigate the electronic and magnetic structures of each atomic layer at subsurface, we have proposed a new method, Auger electron diffraction spectroscopy, which is the combination of x-ray absorption spectroscopy (XAS) and Auger electron diffraction (AED) techniques. We have measured a series of Ni LMM AED patterns of the Ni film grown on Cu(001) surface for various thicknesses. Then we deduced a set of atomic-layer-specific AED patterns in a numerical way. Furthermore, we developed an algorithm to disentangle XANES spectra from different atomic layers using these atomic-layer-specific AED patterns. Surface and subsurface core level shift were determined for each atomic layer.

Matsui, Fumihiko; Matsushita, Tomohiro; Kato, Yukako; Hashimoto, Mie; Daimon, Hiroshi

2009-11-01

414

Simulating picosecond X-ray diffraction from crystals using FFT methods on MD output  

SciTech Connect

Multi-million atom non-equilibrium molecular dynamics (MD) simulations give significant insight into the transient processes that occur under shock compression. Picosecond X-ray diffraction enables the probing of materials on a timescale fast enough to test such effects. In order to simulate diffraction patterns, Fourier methods are required to gain a picture of reciprocal lattice space. We present here results of fast Fourier transforms of atomic coordinates of shocked crystals simulated by MD, and comment on the computing power required as a function of problem size. The relationship between reciprocal space and particular experimental geometries is discussed.

Kimminau, Giles; Nagler, Bob; Higginbotham, Andrew; Murphy, William; Wark, Justin [Department of Physics, Clarendon Laboratory, Parks Road, University of Oxford, OX1 3PU (United Kingdom); Park, Nigel [AWE, Aldermaston (United Kingdom); Hawreliak, James; Kalantar, Dan; Lorenzana, Hector; Remington, Bruce [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States)

2007-12-12

415

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

416

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

PubMed

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; Sch黮ein, Florian J R; Krenner, Hubert J; Wixforth, Achim; Salditt, Tim

2014-10-01

417

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

418

Magnetic-field-induced orientation of superconducting MgB2 crystallites determined by x-ray diffraction  

E-print Network

Magnetic-field-induced orientation of superconducting MgB2 crystallites determined by x-ray; published 4 August 2006 X-ray diffraction studies of fine polycrystalline samples of MgB2 the isotropic value =1 see Fig. 4 in Ref. 14 . Some experi- mental studies claim that the H T,H = T,H .12

Vakni, David

419

X-RAY DIFFRACTION STUDY OF CRYSTAL TRANSFORMATIONS IN SPHERULITIC AMYLOSE/LIPID COMPLEXES FROM JET-COOKED STARCH  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effects of drying, solvent extraction and rehydration on the structures of V-type amylose/lipid complexes from slowly cooled jet-cooked corn starch dispersions were investigated using X-ray powder diffraction. Large spherulites in the wet state or dried in humid air had X-ray patterns similar t...

420

Versatile wide angle diffraction setup for simultaneous wide and small angle x-ray scattering measurements with synchrotron radiation  

Microsoft Academic Search

Here we present a novel, simple, and versatile experimental setup aimed to perform wide angle x-ray scattering (WAXS) measurements alone or in simultaneous combination with small angle x-ray scattering measurements. The design of the WAXS goniometer allows one to obtain high resolution diffraction patterns in a broad angular range. The setup can incorporate a hot stage in order to evaluate

D. R. Rueda; M. C. Garc韆-Guti閞rez; A. Nogales; M. J. Capit醤; T. A. Ezquerra; A. Labrador; E. Fraga; D. Beltr醤; J. Juanhuix; J. F. Herranz; J. Bordas

2006-01-01

421

X-ray tube-based diffraction enhanced imaging prototype images of full-thickness breast specimens: reader study evaluation  

Microsoft Academic Search

Conventional mammographic image contrast is derived from x-ray absorption, resulting in breast structure visualization due to density gradients that attenuate radiation without distinction between transmitted and scattered or refracted x-rays. This leads to image blurring and contrast reduction, hindering the early detection of small or otherwise occult cancers. Diffraction enhanced imaging (DEI) allows for dramatically increased contrast with decreased radiation

L. S. Faulconer; C. Parham; D. J. Connor; M. Koomen; C. Kuzmiak; D. Pavic; C. A. Livasy; E. Kim; D. Zeng; E. B. Cole; Z. Zhong; E. D. Pisano

2009-01-01

422

The use of X-ray diffraction for analyzing biomodification of crystalline cellulose by wood decay fungi  

Microsoft Academic Search

X-ray diffraction (XRD) is based on the creation of an interference pattern by x- rays when they encounter a regularly spaced matrix. In wood, this process has been used to determine among other things the average width of the cellulose microcrystals, the percent of crystalline cellulose within the wood, and can be used to examine the changes in these parameters

Caitlin Howell; Anne Christine; Steenkj鎟 Hastrup; Jody Jellison

423

Time-Domain X-ray Diffraction in the Pulsed Laser Heated Diamond Anvil Cell  

NASA Astrophysics Data System (ADS)

We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell (DAC) at pressure up to 100 GPa and 3500 K. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 microseconds pulse width synchronized with a gated x-ray detector (Pilatus) and time resolved radiometric temperature measurements. For the special APS hybrid mode, the measurements were also synchronized with a 500 ns long bunch carrying 88% of the ring current. This setup enables time domain measurements as a function of temperature in a micrometers 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 micrometers thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformity 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. We will show examples of studies of the melting, thermal equation of state, and chemical reactivity. We acknowledge support from NSF EAR-0842057, DOE/ NNSA (CDAC), and EFree, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DESC0001057. X-ray diffraction measurements were performed at GSECARS (APS) supported by DOE Contract No.W-31-109- Eng-38.

Prakapenka, V.; Goncharov, A. F.; Struzhkin, V.; Kantor, I.; Rivers, M. L.; Dalton, D. A.

2011-12-01

424

NEUTRON AND SYNCHROTRON X-RAY FIBER DIFFRACTION STUDIES OF CELLULOSE POLYMORPHS.  

SciTech Connect

Although the crystalline nature of cellulose has been one of most studied structural problems in polymer science there remain many open questions. Cellulose is a polymer formed by (1-4)-linked {beta}-D-glucosyl residues that are alternately rotated by 180o along the polymer axis to form flat ribbon-like chains. Each glucosyl unit bears three hydroxyl groups, one an hydroxymethyl group. It has been long recognized that these hydroxyl groups and their ability to bond via hydrogen bonding not only play a major role in directing how the crystal structure of cellulose forms but also in governing important physical properties of cellulose materials. Through the development of new techniques we have been able to prepare fiber samples of cellulose with exceptionally high order. The quality of these samples is allowing us to exploit the unique properties of synchrotron X-ray and neutron sources in order to collect diffraction data to near atomic resolution. Synchrotron X-rays are used to provide accurate crystallographic parameters for C and O atoms. However, because of the relatively weak scattering power of H atoms for X-rays, neutrons are used to determine H atom parameters. We have developed methods for replacing labile H atoms with D, without any loss in crystalline perfection. Deuterated fibers can diffract neutrons with intensities that are substantially different from the intensities diffracted from hydrogenated fibers. These differences, along with the phases calculated from the C and O positions determined in our X-ray studies, are used to calculate Fourier difference syntheses in which density associated with labile hydrogen atoms is imaged. The unprecedented high resolution of these data is revealing new information on cellulose structure and hydrogen bonding.

Los Alamos National Laboratory

2001-01-01

425

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

426

Synchrotron Powder X-ray Diffraction Study of the Structure and Dehydration Behavior of Sepiolite  

NASA Astrophysics Data System (ADS)

Sepiolite is a hydrous Mg-silicate clay mineral with fibrous morphology that typically occurs as fine-grained, poorly crystalline masses. It occurs in a wide variety of geological environments and has been mined for centuries because of its many uses, e.g. in the pharmaceutical, fertilizer, and pesticide industries. Its versatile functionality derives from the large surface area and microporosity that are characteristic of the material. In recent years, sepiolite has received considerable attention with regard to the adsorption of organics, for use as a support for catalysts, as a molecular sieve, and as an inorganic membrane for ultrafiltration. Because of its fine-grained and poorly crystalline nature, it has not been possible to study sepiolite's crystal structure using single-crystal X-ray diffraction methods, and consequently many details of the structure are still not well known. In this study, Rietveld refinements using synchrotron powder X-ray diffraction data were used to investigate 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 water site. The RT structure under vacuum retained only ~1/8 of the zeolitic water and the volume decreased 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 water is lost by ~390 K, accompanied by a decrease in the a and c unit-cell parameters. Above ~600 K the sepiolite structure folds as one-half of the crystallographically bound water is lost. Rietveld refinements of the "anhydrous" sepiolite structure reveal that, in general, unit-cell parameters a, b, and volume steadily decrease with increasing temperature; there is an obvious change in slope at ~820 K suggesting a phase transformation coinciding with the loss of the remaining bound water molecule. These temperature-resolved real-time powder X-ray diffraction studies provide the first comprehensive description of the sepiolite structure and the complex changes it undergoes as it dehydrates. Additional heating and cooling in situ powder X-ray diffraction experiments are underway in order to investigate the relative stabilities and rehydration behaviors of the partially-hydrated sepiolite phases. The results of these studies should provide a more robust model for predicting and modifying the properties and applications of this critical industrial material and environmentally important mineral.

Post, J. E.; Bish, D. L.; Heaney, P. J.

2006-05-01

427

Energy dispersive X-ray diffraction in the diamond anvil, high-pressure apparatus - Comparison of synchrotron and conventional X-ray sources  

NASA Technical Reports Server (NTRS)

The use of both conventional fixed-anode X-ray sources and synchrotron radiation to carry out energy-dispersive X-ray diffraction experiments at high pressure in a diamond anvil cell, is discussed. The photon flux at the sample and at the detector for the two cases are compared and the results are presented in graphs. It is shown that synchrotron radiation experiments can be performed with nearly two orders of magnitude increase in data rate if superior detectors and detector electronics are available.

Spain, I. L.; Black, D. R.

1985-01-01

428

Lattice imperfections studied by x-ray diffraction in deformed aluminum-base alloys: Al-Ge alloy  

NASA Astrophysics Data System (ADS)

In the present analysis, which is part of a series on a study that has been undertaken on aluminum-base alloys, a detailed X-ray diffraction study of deformation[1 5] is made on aluminum-base germanium alloys in four different compositions: Al-3.10 at. pct Ge, Al-3.80 at. pct Ge, Al-4.16 at. pct Ge, and Al-4.60 at. pct Ge. The alloys were prepared from spectroscopically pure metals supplied by Johnson-Matthey and Co. Ltd., London, by melting them in graphite crucibles sealed under vacuum in quartz capsules. The alloys were homogenized for 15 days at 400 癈 in the face-centered cubic phase (Figure 1), and cold working was performed by careful hand filing at room temperature. The diffractometer samples were prepared in the usual manner,[3,4] and X-ray diffraction profiles were recorded in a Siemens Kristalloflex-4 X-ray diffractometer using Cu K? radiation. A portion of the powder obtained by hand filing from each alloy was annealed at 400 癈 to relieve strain and was taken as standard for line shift, line asymmetry, and line shape analyses in light of recent developments.[3,4,6 8] The microstructural parameters, such as coherent domain size ( D e, microstrain , stacking faults ?' and a" (both intrinsic and extrinsic), deformation twin fault ?, dislocation density ?, and stacking fault energy parameter ?/?, were determined by adopting the same method of analysis and following the same equations that were used before.[3 7

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

1990-09-01

429

A-DNA and B-DNA: Comparing Their Historical X-ray Fiber Diffraction Images  

NASA Astrophysics Data System (ADS)

A-DNA and B-DNA are two secondary molecular conformations (among other allomorphs) that double-stranded DNA drawn into a fiber can assume, depending on the relative water content and other chemical parameters of the fiber. They were the first two forms to be observed by X-ray fiber diffraction in the early 1950s, respectively by Wilkins and Gosling and by Franklin and Gosling. Their corresponding historical diffraction diagrams played an equally crucial role in the discovery of the primary double-helical structure of the DNA molecule by Watson and Crick in 1953. This paper provides a comparative explanation of the structural content of the two diagrams treated on the same footing. The analysis of the diagrams is supported by the optical transform method with which both A-DNA and B-DNA X-ray images can be simulated optically. The simulations use a simple laser pointer and a dozen optical diffraction gratings, all held on a single diffraction slide. The gratings have been specially designed to pinpoint just which of the structural elements of the molecule is responsible for each of the revealing features of the fiber diffraction images.

Lucas, Amand A.

2008-05-01

430

Strength and structural phase transitions of gadolinium at high pressure from radial X-ray diffraction  

NASA Astrophysics Data System (ADS)

Lattice strength and structural phase transitions of gadolinium (Gd) were determined under nonhydrostatic compression up to 55 GPa using an angle-dispersive radial x-ray diffraction technique in a diamond-anvil cell at room temperature. Three new phases of fcc structure, dfcc structure, and new monoclinic structure were observed at 25 GPa, 34 GPa, and 53 GPa, respectively. The radial x-ray diffraction data yield a bulk modulus K0 = 36(1) GPa with its pressure derivate K0' = 3.8(1) at the azimuthal angle between the diamond cell loading axis and the diffraction plane normal and diffraction plane ? = 54.7. With K0' fixed at 4, the derived K0 is 34(1) GPa. In addition, analysis of diffraction data with lattice strain theory indicates that the ratio of differential stress to shear modulus (t/G) ranges from 0.011 to 0.014 at pressures of 12-55 GPa. Together with estimated high-pressure shear moduli, our results show that Gd can support a maximum differential stress of 0.41 GPa, while it starts to yield to plastic deformation at 16 GPa under uniaxial compression. The yield strength of Gd remains approximately a constant with increasing pressure, and reaches 0.46 GPa at 55 GPa.

Xiong, Lun; Liu, Jing; Bai, Ligang; Li, Xiaodong; Lin, Chuanlong; Lin, Jung-Fu

2014-12-01

431

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

432

Vibrational Spectroscopy and X-ray Diffraction of Cd(OH)2 to 28GPa at 300 K  

SciTech Connect

We report Raman and infrared absorption spectroscopy alongwith X-ray diffraction for brucite-type beta-Cd(OH)2 to 28 GPa at 300 K.The OH-stretching modes soften with pressure and disappear at 21 GPa withtheir widths increasing rapidly above 5 GPa, consistent with a gradualdisordering of the H sublattice at 5 20 GPa similar to that previouslyobserved for Co(OH)2.Asymmetry in the peak shapes of the OH-stretchingmodes suggests the existence of diverse disordered sitesfor H atoms inCd(OH)2 under pressure. Above 15 GPa, the A1g(T) lattice mode showsnon-linear behavior and softens to 21 GPa, at which pressure significantchanges are observed: new Raman modes appear, two Raman-active latticemodes and the OH-stretching modes of the low-pressure phase disappears,and the positions of some X-ray diffraction lines change abruptly withthe appearance of weak new diffraction features. These observationssuggest that amorphization of the H sublattice is accompanied by acrystalline-to-crystalline transition at 21 GPa in Cd(OH)2, which has notbeen previously observed in the brucite-type hydroxides. The Ramanspectra of the high-pressure phase of Cd(OH)2 is similar to those of thehigh-pressure phase of single-crystal Ca(OH)2 of which structure has beententatively assigned to the Sr(OH)2 type.

Shim, Sang-Heon; Rekhi, Sandeep; Martin, Michael C.; Jeanloz,Raymond

2006-03-20

433

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.

J髇i, B.; Gonda, V.; Ver, B.; Ung醨, T.

2014-08-01

434

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

435

Mineral identification in Colombian coals using M鰏sbauer spectroscopy and X-ray diffraction  

NASA Astrophysics Data System (ADS)

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

Fajardo, M.; Mojica, J.; Barraza, J.; P閞ez Alc醶ar, G. A.; Tabares, J. A.

1999-11-01

436

Flux monitoring by x-ray diffracting crystals under ambient air conditions  

NASA Astrophysics Data System (ADS)

An electrical response of a diffracting diamond (111) crystal was studied in a single electrode configuration where the electrode was deposited on a small portion of the crystal entrance surface. The experiment was performed in ambient air using an x-ray beam after a Si (111) double-crystal monochromator with the diamond crystal set in the Bragg diffraction condition. It was found that the electric current as a function of the Bragg angle exhibits behavior characteristic of secondary yield curves (e.g.,1). It is proposed to utilize this effect to monitor the intensity of the Bragg reflected x-ray beam. Such non-invasive monitoring does not rely on the use of stand-alone radiation monitors (e.g., ionization chambers) and is expected to facilitate x-ray optics alignment procedures. As an attempt to improve signal-to-noise ratio by containing the electric field in the optical element an electric response of a high-resistivity silicon crystal was studied in a two-electrode configuration. Preliminary results are reported.

Stoupin, Stanislav; Baryshev, Sergey V.; Antipov, Sergey P.

2014-09-01

437

Data preparation and evaluation techniques for x-ray diffraction microscopy  

DOE PAGESBeta

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.

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

2010-01-01

438

Nondestructive evaluation of residual stress in short-fiber reinforced plastics by x-ray diffraction  

NASA Astrophysics Data System (ADS)

The X-ray diffraction method is used to measure the residual stress in injection-molded plates of short-fiber reinforced plastics (SFRP) made of crystalline thermoplastics, polyphenylene sulphide (PPS), reinforced by carbon fibers with 30 mass%. Based on the orientation of carbon fibers, injection molded plates can be modeled as three-layered lamella where the core layer is sandwiched by skin layers. The stress in the matrix in the skin layer was measured using Cr-K? radiation with the sin2? method. Since the X-ray penetration depth is shallow, the state of stresses measured by X-rays in FRP can be assumed to be plane stress. The X-ray measurement of stress in carbon fibers was not possible because of high texture. A new method was proposed to evaluate the macrostress in SFRP from the measurement of the matrix stress. According to micromechanics analysis of SFRP, the matrix stresses in the fiber direction, ?1m, and perpendicular to the fiber direction, ?2m, and shear stress ?12m can be expressed as the functions of the applied (macro-) stresses, ?1A, ?2A , ?12A as follows: ?1m = ?11?1A +?12?2A, ?2m = ?21?1A + ?22?2A, ?12m = ?66?12A, where ?11 ,?12, ?21, ?22, ?66 are stress-partitioning coefficients. Using skin-layer strips cut parallel, perpendicular and 45 to the molding direction, the stress in the matrix was measured under the uniaxial applied stress and the stress-partitioning coefficients of the above equations were determined. Once these relations are established, the macrostress in SFRP can be determined from the measurements of the matrix stresses by X-rays.

Tanaka, Keisuke; Tokoro, Syouhei; Akiniwa, Yoshiaki; Egami, Noboru

2014-06-01

439

Determination of global and local residual stresses in SOFC by X-ray diffraction  

NASA Astrophysics Data System (ADS)

Solid Oxide Fuel Cell (SOFC) is a high-performance electrochemical device for energy conversion. A single cell is composed of five layers made of different ceramic materials: anode support, anode functional layer, electrolyte, cathode functional layer and cathode. The mechanical integrity of the cell is a major issue during its lifetime, especially for the electrolyte layer. Damage of the cells is mainly due to the high operating temperature, the "redox" behaviour of the anode and the brittleness of the involved materials. Since residual stresses are known to play a significant role in the damage evolution, it is important to determine them. For this purpose, residual stresses in an anode-supported planar SOFC were measured by X-ray diffraction. Firstly, macroscopic stresses in each phase of each layer were studied using the sin 2? method on a laboratory X-ray goniometer at room temperature. This technique enables the calculation of residual stress of the material from the measurement of the crystal lattice deformation. The electrolyte has been found under bi-axial compressive stress of -920 MPa. Secondly, X-ray measurements controlling depth penetration were made in the electrolyte using grazing incidence method. The results show that the stress is not homogenous in the layer. The first five micrometers of the electrolyte have been found less constrained (-750 MPa) than the complete layer, suggesting a gradient of deformation in the electrolyte from the interface with the Anode Functional Layer to the free surface. Finally, local stress measurements were made on the electrolyte layer by X-ray synchrotron radiation that allows high accuracy measurement on the (sub-) micrometer scale. Polychromatic and monochromatic beams are used to determine the complete strain tensor from grain to grain in the electrolyte. First results confirm the macroscopic stress trend of the electrolyte. These X-ray techniques at different scales will contribute to a better understanding of the residual stress in the electrolyte layer and thus to the involved damage mechanisms.

Villanova, Julie; Sicardy, Olivier; Fortunier, Roland; Micha, Jean-S閎astien; Bleuet, Pierre

2010-02-01

440

Line-source based X-ray Tomography Deepak Bharkhada1,2  

E-print Network

reconstruction technique (SART) algorithm for image reconstruction from projection data generated by an x-rayLine-source based X-ray Tomography Deepak Bharkhada1,2 , Hengyong Yu4 , Hong Liu3 , Robert Plemmons5 , Ge Wang1,2,4 1. Biomedical Imaging Division, VT-WFU School of Biomedical Engineering & Science

Plemmons, Robert J.

441

Three-dimensional diffraction mapping by tuning the X-ray energy.  

PubMed

Three-dimensional reciprocal-space maps of a single SiGe island around the Si(004) Bragg peak are recorded using an energy-tuning technique with a microfocused X-ray beam with compound refractive lenses as focusing optics. The map is in agreement with simulated data as well as with a map recorded by an ordinary rocking-curve scan. The energy-tuning approach circumvents both the comparatively large sphere of confusion of diffractometers compared with nanostructures and vibrations induced by motors. Thus, this method offers new possibilities for novel combinations of three-dimensional micro- and nano-focused X-ray diffraction with complex in situ sample environments such as scanning probe microscopes. PMID:21525649

Cornelius, T W; Carbone, D; Jacques, V L R; Sch黮li, T U; Metzger, T H

2011-05-01

442

X-ray Diffraction Results from Mars Science Laboratory: Mineralogy of Rocknest at Gale Crater  

NASA Astrophysics Data System (ADS)

The Mars Science Laboratory rover Curiosity scooped samples of soil from the Rocknest aeolian bedform in Gale crater. Analysis of the soil with the Chemistry and Mineralogy (CheMin) x-ray diffraction (XRD) instrument revealed plagioclase (~An57), forsteritic olivine (~Fo62), augite, and pigeonite, with minor K-feldspar, magnetite, quartz, anhydrite, hematite, and ilmenite. The minor phases are present at, or near, detection limits. The soil also contains 27 14 weight percent x-ray amorphous material, likely containing multiple Fe3+- and volatile-bearing phases, including possibly a substance resembling hisingerite. The crystalline component is similar to the normative mineralogy of certain basaltic rocks from Gusev crater on Mars and of martian basaltic meteorites. The amorphous component is similar to that found on Earth in places such as soils on the Mauna Kea volcano, Hawaii.

Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Chipera, S. J.; Morris, R. V.; Ming, D. W.; Treiman, A. H.; Sarrazin, P.; Morrison, S. M.; Downs, R. T.; Achilles, C. N.; Yen, A. S.; Bristow, T. F.; Crisp, J. A.; Morookian, J. M.; Farmer, J. D.; Rampe, E. B.; Stolper, E. M.; Spanovich, N.; Achilles, Cherie; Agard, Christophe; Verdasca, Jos Alexandre Alves; Anderson, Robert; Anderson, Ryan; Archer, Doug; Armiens-Aparicio, Carlos; Arvidson, Ray; Atlaskin, Evgeny; Atreya, Sushil; Aubrey, Andrew; Baker, Burt; Baker, Michael; Balic-Zunic, Tonci; Baratoux, David; Baroukh, Julien; Barraclough, Bruce; Bean, Keri; Beegle, Luther; Behar, Alberto; Bell, James; Bender, Steve; Benna, Mehdi; Bentz, Jennifer; Berger, Gilles; Berger, Jeff; Berman, Daniel; Bish, David; Blake, David F.; Avalos, Juan J. Blanco; Blaney, Diana; Blank, Jen; Blau, Hannah; Bleacher, Lora; Boehm, Eckart; Botta, Oliver; B鰐tcher, Stephan; Boucher, Thomas; Bower, Hannah; Boyd, Nick; Boynton, Bill; Breves, Elly; Bridges, John; Bridges, Nathan; Brinckerhoff, William; Brinza, David; Bristow, Thomas; Brunet, Claude; Brunner, Anna; Brunner, Will; Buch, Arnaud; Bullock, Mark; Burmeister, S鰊ke; Cabane, Michel; Calef, Fred; Cameron, James; Campbell, John "Iain"; Cantor, Bruce; Caplinger, Michael; Rodr韌uez, Javier Caride; Carmosino, Marco; Bl醶quez, Isa韆s Carrasco; Charpentier, Antoine; Chipera, Steve; Choi, David; Clark, Benton; Clegg, Sam; Cleghorn, Timothy; Cloutis, Ed; Cody, George; Coll, Patrice; Conrad, Pamela; Coscia, David; Cousin, Agn鑣; Cremers, David; Crisp, Joy; Cros, Alain; Cucinotta, Frank; d'Uston, Claude; Davis, Scott; Day, Mackenzie "Kenzie"; Juarez, Manuel de la Torre; DeFlores, Lauren; DeLapp, Dorothea; DeMarines, Julia; DesMarais, David; Dietrich, William; Dingler, Robert; Donny, Christophe; Downs, Bob; Drake, Darrell; Dromart, Gilles; Dupont, Audrey; Duston, Brian; Dworkin, Jason; Dyar, M. Darby; Edgar, Lauren; Edgett, Kenneth; Edwards, Christopher; Edwards, Laurence; Ehlmann, Bethany; Ehresmann, Bent; Eigenbrode, Jen; Elliott, Beverley; Elliott, Harvey; Ewing, Ryan; Fabre, C閏ile; Fair閚, Alberto; Farley, Ken; Farmer, Jack; Fassett, Caleb; Favot, Laurent; Fay, Donald; Fedosov, Fedor; Feldman, Jason; Feldman, Sabrina; Fisk, Marty; Fitzgibbon, Mike; Flesch, Greg; Floyd, Melissa; Fl點kiger, Lorenzo; Forni, Olivier; Fraeman, Abby; Francis, Raymond; Fran鏾is, Pascaline; Franz, Heather; Freissinet, Caroline; French, Katherine Louise; Frydenvang, Jens; Gaboriaud, Alain; Gailhanou, Marc; Garvin, James; Gasnault, Olivier; Geffroy, Claude; Gellert, Ralf; Genzer, Maria; Glavin, Daniel; Godber, Austin; Goesmann, Fred; Goetz, Walter; Golovin, Dmitry; G髆ez, Felipe G髆ez; G髆ez-Elvira, Javier; Gondet, Brigitte; Gordon, Suzanne; Gorevan, Stephen; Grant, John; Griffes, Jennifer; Grinspoon, David; Grotzinger, John; Guillemot, Philippe; Guo, Jingnan; Gupta, Sanjeev; Guzewich, Scott; Haberle, Robert; Halleaux, Douglas; Hallet, Bernard; Hamilton, Vicky; Hardgrove, Craig; Harker, David; Harpold, Daniel; Harri, Ari-Matti; Harshman, Karl; Hassler, Donald; Haukka, Harri; Hayes, Alex; Herkenhoff, Ken; Herrera, Paul; Hettrich, Sebastian; Heydari, Ezat; Hipkin, Victoria; Hoehler, Tori; Hollingsworth, Jeff; Hudgins, Judy; Huntress, Wesley; Hurowitz, Joel; Hviid, Stubbe; Iagnemma, Karl; Indyk, Steve; Isra雔, Guy; Jackson, Ryan; Jacob, Samantha; Jakosky, Bruce; Jensen, Elsa; Jensen, Jaqueline Kl鴙gaard; Johnson, Jeffrey; Johnson, Micah; Johnstone, Steve; Jones, Andrea; Jones, John; Joseph, Jonathan; Jun, Insoo; Kah, Linda; Kahanp滗, Henrik; Kahre, Melinda; Karpushkina, Natalya; Kasprzak, Wayne; Kauhanen, Janne; Keely, Leslie; Kemppinen, Osku; Keymeulen, Didier; Kim, Myung-Hee; Kinch, Kjartan; King, Penny; Kirkland, Laurel; Kocurek, Gary; Koefoed, Asmus; K鰄ler, Jan; Kortmann, Onno; Kozyrev, Alexander; Krezoski, Jill; Krysak, Daniel; Kuzmin, Ruslan; Lacour, Jean Luc; Lafaille, Vivian; Langevin, Yves; Lanza, Nina; Lasue, Jeremie; Le Mou閘ic, St閜hane; Lee, Ella Mae; Lee, Qiu-Mei; Lees, David; Lefavor, Matthew; Lemmon, Mark; Malvitte, Alain Lepinette; Leshin, Laurie; L関eill, Richard; Lewin-Carpintier, 蓃ic; Lewis, Kevin; Li, Shuai; Lipkaman, Leslie; Little, Cynthia; Litvak, Maxim; Lorigny, Eric; Lugmair, Guenter; Lundberg, Angela; Lyness, Eric; Madsen, Morten; Mahaffy, Paul; Maki, Justin; Malakhov, Alexey; Malespin, Charles; Malin, Michael; Mangold, Nicolas; Manhes, G閞ard; Manning, Heidi; Marchand, Genevi鑦e; Jim閚ez, Mercedes Mar韓; Garc韆, C閟ar Mart韓; Martin, Dave; Martin, Mildred; Mart韓ez-Fr韆s, Jes鷖; Mart韓-Soler, Javier; Mart韓-Torres, F. Javier; Mauchien, Patrick

2013-09-01

443

Time-, frequency-, and wavevector-resolved x-ray diffraction from single molecules  

SciTech Connect

Using a quantum electrodynamic framework, we calculate the off-resonant scattering of a broadband X-ray pulse from a sample initially prepared in an arbitrary superposition of electronic states. The signal consists of single-particle (incoherent) and two-particle (coherent) contributions that carry different particle form factors that involve different material transitions. Single-molecule experiments involving incoherent scattering are more influenced by inelastic processes compared to bulk measurements. The conditions under which the technique directly measures charge densities (and can be considered as diffraction) as opposed to correlation functions of the charge-density are specified. The results are illustrated with time- and wavevector-resolved signals from a single amino acid molecule (cysteine) following an impulsive excitation by a stimulated X-ray Raman process resonant with the sulfur K-edge. Our theory and simulations can guide future experimental studies on the structures of nano-particles and proteins.

Bennett, Kochise, E-mail: kcbennet@uci.edu; Biggs, Jason D.; Zhang, Yu; Dorfman, Konstantin E.; Mukamel, Shaul, E-mail: smukamel@uci.edu [University of California, Irvine, California 92697-2025 (United States)

2014-05-28

444

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

445

Structure determination of thin CoFe films by anomalous x-ray diffraction  

SciTech Connect

This work reports on the investigation of structure-property relationships in thin CoFe films grown on MgO. Because of the very similar scattering factors of Fe and Co, it is not possible to distinguish the random A2 (W-type) structure from the ordered B2 (CsCl-type) structure with commonly used x-ray sources. Synchrotron radiation based anomalous x-ray diffraction overcomes this problem. It is shown that as grown thin films and 300 K post annealed films exhibit the A2 structure with a random distribution of Co and Fe. In contrast, films annealed at 400 K adopt the ordered B2 structure.

Gloskovskii, Andrei; Stryganyuk, Gregory; Ouardi, Siham [Institut fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); Fecher, Gerhard H.; Felser, Claudia [Institut fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden (Germany); Hamrle, Jaroslav; Pistora, Jaromir [Department of Physics and Nanotechnology Centre, VSB-Technical University of Ostrava, 70833 Ostrava (Czech Republic); Bosu, Subrojati; Saito, Kesami; Sakuraba, Yuya; Takanashi, Koki [Institute for Materials Research (IMR), Tohoku University, Sendai 980-8577 (Japan)

2012-10-01

446

Time-, frequency-, and wavevector-resolved x-ray diffraction from single molecules  

NASA Astrophysics Data System (ADS)

Using a quantum electrodynamic framework, we calculate the off-resonant scattering of a broadband X-ray pulse from a sample initially prepared in an arbitrary superposition of electronic states. The signal consists of single-particle (incoherent) and two-particle (coherent) contributions that carry different particle form factors that involve different material transitions. Single-molecule experiments involving incoherent scattering are more influenced by inelastic processes compared to bulk measurements. The conditions under which the technique directly measures charge densities (and can be considered as diffraction) as opposed to correlation functions of the charge-density are specified. The results are illustrated with time- and wavevector-resolved signals from a single amino acid molecule (cysteine) following an impulsive excitation by a stimulated X-ray Raman process resonant with the sulfur K-edge. Our theory and simulations can guide future experimental studies on the structures of nano-particles and proteins.

Bennett, Kochise; Biggs, Jason D.; Zhang, Yu; Dorfman, Konstantin E.; Mukamel, Shaul