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1

Wavelength dispersive X-ray fluorescence imaging.  

PubMed

A new wavelength-dispersive X-ray fluorescence (WD-XRF) imaging spectrometer equipped with a two-dimensional X-ray detector was developed in the laboratory. Straight polycapillary optics was applied instead of a soller slit, which is used in conventional WD-XRF spectrometers. X-rays were guided through the straight polycapillary to the exit of the optics by X-ray external total reflections. X-ray fluorescence was dispersed by an analyzing crystal (LiF(200)), keeping the information of elemental distribution on the surface of the sample. The energy resolution of the developed spectrometer was 130-152 eV at the Zn K? peak. X-ray elemental images of Cu K? and Ni K? were successfully obtained by an X-ray CCD detector at the corresponding diffraction angles. The analytical performance of this technique, and further improvements are discussed. PMID:21749148

Tsuji, Kouichi; Ohmori, Takashi; Yamaguchi, Makoto

2011-07-27

2

A multi-crystal wavelength dispersive x-ray spectrometer  

SciTech Connect

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

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

2012-07-15

3

Determination of water content in silica nanopowder using wavelength-dispersive X-ray fluorescence spectrometer  

Microsoft Academic Search

A wavelength-dispersive X-ray fluorescence (WDXRF) technique that uses the scattered radiation of the X-ray tube lines and the fluorescence radiation of an element present in a powder sample is proposed as a non-destructive method for the determination of the water content in silica powder. Although direct X-ray fluorescence analysis of water using WDXRF is not adequate for the quantitative determination

Yong Suk Choi; Jong-Yun Kim; Suk Bon Yoon; Kyuseok Song; Young Jin Kim

2011-01-01

4

X-ray analysis and mapping by wavelength dispersive X-ray spectroscopy in an electron microscope  

Microsoft Academic Search

A compact and easy-to-use wavelength dispersive X-ray spectrometer using a multi-capillary X-ray lens attached to a scanning (transmission) electron microscope has been tested for thin-film analysis. B–K spectra from thin-film boron compounds (B4C, h-BN, and B2O3) samples showed prominent peak shifts and detailed structural differences. Mapping images of a thin W\\/Si double-layer sample resolved each element clearly. Additionally, a thin

Miyoko Tanaka; Masaki Takeguchi; Kazuo Furuya

2008-01-01

5

Wavelength-dispersive spectrometer for X-ray microfluorescence analysis at the X-ray microscopy beamline ID21 (ESRF)  

PubMed Central

The development of a wavelength-dispersive spectrometer for microfluorescence analysis at the X-ray Microscopy ID21 beamline of the European Synchrotron Radiation Facility (ESRF) is reported. The spectrometer is based on a polycapillary optic for X-ray fluorescence collection and is operated in a flat-crystal geometry. The design considerations as well as operation characteristics of the spectrometer are presented. The achieved performances, in particular the energy resolution, are compared with the results of Monte Carlo simulations. Further improvement in the energy resolution, down to ?eV range, by employing a double-crystal geometry is examined. Finally, examples of applications requiring both spatial and spectral resolutions are presented.

Szlachetko, J.; Cotte, M.; Morse, J.; Salome, M.; Jagodzinski, P.; Dousse, J.-Cl.; Hoszowska, J.; Kayser, Y.; Susini, J.

2010-01-01

6

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

SciTech Connect

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

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

2009-01-01

7

Wavelength dispersing devices for soft and ultrasoft x-ray spectrometers  

SciTech Connect

Monochromatization combining total reflection by a selected mirror and an appropriate filter offered an alternative approach in order to increase measurable intensity with reasonable spectral resolution. Recently, the use of synthetic multilayers, which are prepared by sputter/evaporation techniques, has been introduced for the detection of soft and ultrasoft x-rays. Studies on the use of these new wavelength dispersing devices have been conducted and it has been found that the reflectivity of these devices is very high compared with single crystals and soap multilayers and that their resolving power is fairly good. This report makes comparisons regarding efficiency of reflection, resolving power and x-ray analytical problems for practical applications among long spacing single crystals, soap multilayers, total reflection combined with a selected mirror and filtering and synthetic multilayers. The x-ray analytical capablities are shown based upon a standard x-ray fluorescence spectrometer equipped with a sealed-off x-ray tube and a gas flow proportional counter with thin film detector window.

Arai, Tomoya; Ryon, R.W.; Shoji, Takashi

1984-01-01

8

Monochromatic wavelength dispersive x-ray fluorescence providing sensitive and selective detection of uranium  

SciTech Connect

Monochromatic wavelength dispersive X-ray fluorescence (MWDXRF) is a sensitive and selective method for elemental compositional analyses. The basis for this instrumental advance is the doubly curved crystal (DCC) optic. Previous work has demonstrated the feasibility of sensitive trace element detection for yttrium as a surrogate for curium in aqueous solutions. Additional measurements have demonstrated similar sensitivity in several different matrix environments which attests to the selectivity of the DCC optic as well as the capabilities of the MWDXRF concept. The objective of this effort is to develop an improved Pu characterization method for nuclear fuel reprocessing plants. The MWDXRF prototype instrument is the second step in a multi-year effort to achieve an improved Pu assay. This work will describe a prototype MWDXRF instrument designed for uranium detection and characterization. The prototype consists of an X-ray tube with a rhodium anode and a DCC excitation optic incorporated into the source. The DCC optic passes the RhK{alpha} line at 20.214 keV for monochromatic excitation of the sample. The source is capable of 50 W power at 50 kV and 1.0 mA operation. The x-ray emission from the sample is collected by a DCC optic set at the UL{alpha} line of 13.613 keV. The collection optic transmits the UL{alpha} x-rays to the silicon drift detector. The x-ray source, sample, collection optic and detector are all mounted on motion controlled stages for the critical alignment of these components. The sensitivity and selectivity of the instrument is obtained through the monochromatic excitation and the monochromatic detection. The prototype instrument performance has a demonstrated for sensitivity for uranium detection of around 2 ppm at the current state of development. Further improvement in sensitivity is expected with more detailed alignment.

Havrilla, George J [Los Alamos National Laboratory; Collins, Michael L [Los Alamos National Laboratory; Montoya, Velma M [Los Alamos National Laboratory; Chen, Zewu [XOS; Wei, Fuzhong [XOS

2010-01-01

9

Wavelength dispersive X-ray fluorescence imaging using a high-sensitivity imaging sensor  

NASA Astrophysics Data System (ADS)

A new wavelength-dispersive X-ray fluorescence (WD-XRF) imaging spectrometer equipped with a high-sensitivity imaging sensor was developed in our laboratory. In this instrument, a straight polycapillary optic was applied instead of a Soller slit as well as a 2D imaging X-ray detector instead of X-ray counters, which are used in conventional WD-XRF spectrometers. Therefore, images of elemental distribution were available after a short exposure time. Ni K? images and Cu K? images were clearly obtained at corresponding diffraction angles for a short exposure time of 10 s. By optimizing the spectrometer, the time required for imaging is reduced, leading to XRF image movies. It is difficult to distinguish two peaks (Ti K? (4.508 keV) and Ba L? (4.465 keV)) due to the poor energy resolution of EDXRS. However, Ti and Ba images could be successfully observed by the WD-XRF imaging spectrometer. The energy resolution of the developed spectrometer was 25 eV at the Ti K? peak.

Ohmori, Takashi; Kato, Shuichi; Doi, Makoto; Shoji, Takashi; Tsuji, Kouichi

2013-05-01

10

Wavelength-Dispersive Total Reflection X-Ray Fluorescence with High-Brilliance Undulator Radiation at SPring8  

Microsoft Academic Search

Wavelength-dispersive total reflection X-ray fluorescence (WD-TXRF) equipment supported by an energy-dispersive (ED) solid-state detector (SSD) has been developed and installed in the BL16XU Industrial Consortium ID Beamline for Material Research at the SPring-8 synchrotron radiation research facility. Equipment specifications are given and results from our initial experiment are discussed in this paper. In the experiment on the sensitivity of detection

Naoki Awaji; Shinji Ozaki; Junichi Nishino; Sinichi Noguchi; Tohru Yamamoto; Takashi Syoji; Motoyuki Yamagami; Akira Kobayashi; You Hirai; Masahiro Shibata; Koji Yamaguchi; Kuang-Yu Liu; Seiji Kawado; Mamoru Takahashi; Shigeru Yasuami; Ichiro Konomi; Shigeru Kimura; Yasuharu Hirai; Masaki Hasegawa; Satoshi Komiya; Takayuki Hirose; Toshihiro Okajima

2000-01-01

11

Wavelength dispersive soft X-ray emission spectroscopy attached to TEM using multi-capirary X-ray lens  

Microsoft Academic Search

There is now growing interest in localized chemical bonding states in complex metals and insulators such as those containing\\u000a light elements, rare earths or transition metals because their key spectral features appear in the soft X-ray or vacuum UV\\u000a regions, which is not easily accessible to by SOR light sources and often includes crucial information to understand their\\u000a electronic, optical,

S. Muto; K. Tatsumi; H. Takahashi

12

Controlled dispersion parallel wavelength x-ray spectrometer for electron microscopy.  

National Technical Information Service (NTIS)

This paper describes a new technique for the detection of x-rays in electron column instruments used in microanalysis. In electron column instruments, the point source of x-rays is produced by the interaction of a focused electron beam with the sample. Ne...

C. E. Fiori S. A. Wight A. D. Romig

1991-01-01

13

Determination of ion charge state distributions in krypton and cobalt electron cyclotron resonance plasmas by wavelength dispersive x-ray spectroscopy  

Microsoft Academic Search

Wavelength dispersive x-ray measurements on cobalt and krypton ions were presented to determine the ion charge state distribution (CSD) inside the electron cyclotron resonance (ECR) plasma of the 14.5 GHz ECR ion source of the TU Dresden. For clearly from the parent diagram lines separating x-ray satellites a comparison between calculated wavelength shifts and measured ones allows it to deduce

P. Grübling; D. Küchler; U. Lehnert; A. Ullrich; T. Werner; G. Zschornack

1998-01-01

14

High Gain, Fast Scan, Broad Spectrum, Parallel Beam Wavelength Dispersive X-ray Spectrometer for SEM  

SciTech Connect

Parallax Research, Inc. proposes to produce a new type of x-ray spectrometer for use with Scanning Electron Microscopy (SEM) that would have the energy resolution of WDS and the ease of use of EDS with sufficient gain for lower energies that it can be used at low beam currents as is EDS. Parallax proposes to do this by development of new multiple reflection x-ray collimation optics, new diffractor technology, new detector technology and new scan algorithms.

David OHara; Dr. Eric Lochmer

2003-09-12

15

Wavelength dispersive X-ray fluorescence analysis using fundamental parameter approach of Catha edulis and other related plant samples  

NASA Astrophysics Data System (ADS)

This work is the first attempt to quantify trace elements in the Catha edulis plant (Khat) with a fundamental parameter approach. C. edulis is a famous drug plant in east Africa and Arabian Peninsula. We have previously confirmed that hydroxyapatite represents one of the main inorganic compounds in the leaves and stalks of C. edulis. Comparable plant leaves from basil, mint and green tea were included in the present investigation as well as trifolium leaves were included as a non-related plant. The elemental analyses of the plants were done by Wavelength Dispersive X-Ray Fluorescence (WDXRF) spectroscopy. Standard-less quantitative WDXRF analysis was carried out based on the fundamental parameter approaches. According to the standard-less analysis algorithms, there is an essential need for an accurate determination of the amount of organic material in the sample. A new approach, based on the differential thermal analysis, was successfully used for the organic material determination. The obtained results based on this approach were in a good agreement with the commonly used methods. Depending on the developed method, quantitative analysis results of eighteen elements including; Al, Br, Ca, Cl, Cu, Fe, K, Na, Ni, Mg, Mn, P, Rb, S, Si, Sr, Ti and Zn were obtained for each plant. The results of the certified reference materials of green tea (NCSZC73014, China National Analysis Center for Iron and Steel, Beijing, China) confirmed the validity of the proposed method.

Shaltout, Abdallah A.; Moharram, Mohammed A.; Mostafa, Nasser Y.

2012-01-01

16

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

PubMed

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

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

2012-11-15

17

Soft x-ray beamsplitters and highly dispersive multilayer mirrors for use as soft x-ray laser cavity components  

Microsoft Academic Search

The demonstration of amplified spontaneous emission at soft x-ray wavelengths has highlighted the need for normal incidence optics for soft x-rays. Specifically, x-ray laser cavity components will be needed to further advances in x-ray laser research. In this paper, we present the fabrication, characterization and analysis of two possible cavity components, an x-ray beamsplitter and a highly dispersive multilayer mirror.

A. M. Hawryluk; N. M. Ceglio; D. G. Stearns; K. Danzmann; M. Kuehne; P. Muller; B. Wende

1987-01-01

18

Multiple wavelength X-ray monochromators  

DOEpatents

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

Steinmeyer, Peter A. (Arvada, CO)

1992-11-17

19

NOTES ON EXPERIMENTAL TECHNIQUE AND APPARATUS: Dispersion of 1 A X rays with NPL X-ray gratings  

Microsoft Academic Search

NPL X-ray gratings have been used at glancing angles of incidence down to 5 min of arc, to disperse X-rays of wavelengths below 1 Å. Applications include spectroscopic studies of high temperature plasmas and extra terrestrial X-ray sources.

A. Franks; K. Lindsey

1968-01-01

20

Phosphorus determination in borophosphosilicate or phosphosilicate glass films on a Si wafer by wavelength dispersive x-ray spectroscopy.  

National Technical Information Service (NTIS)

In this report, peak shift effects in the SiO(sub 2)/Si(100) system due to chemical bonding are demonstrated. The detailed development of the equations appears in a paper submitted for publication in the Journal of X-ray Spectroscopy. These equations are ...

H. S. Levine K. L. Higgins

1990-01-01

21

Stoichiometry determination of (Pb,La)(Zr,Ti)O3-type nano-crystalline ferroelectric ceramics by wavelength-dispersive X-ray fluorescence spectrometry.  

PubMed

Analysis of small samples of lanthanum-doped lead zirconate titanate (PLZT) by wavelength-dispersive X-ray fluorescence spectrometry (WDXRF) is presented. The powdered material in ca. 30 mg was suspended in water and collected on the membrane filter. The pure oxide standards (PbO, La2O3, ZrO2 and TiO2) were used for calibration. The matrix effects were corrected using a theoretical influence coefficients algorithm for intermediate-thickness specimens. The results from XRF method were compared with the results from the inductively coupled plasma optical emission spectrometry (ICP-OES). Agreement between XRF and ICP-OES analysis was satisfactory and indicates the usefulness of XRF method for stoichiometry determination of PLZT. PMID:16791580

Sitko, Rafa?; Zawisza, Beata; Kita, Andrzej; P?o?ska, Ma?gorzata

2006-05-10

22

A simple method for detection of gunshot residue particles from hands, hair, face, and clothing using scanning electron microscopy/wavelength dispersive X-ray (SEM/WDX).  

PubMed

We devised a simple and rapid method for detection of gunshot residue (GSR) particles, using scanning electron microscopy/wavelength dispersive X-ray (SEM/WDX) analysis. Experiments were done on samples containing GSR particles obtained from hands, hair, face, and clothing, using double-sided adhesive coated aluminum stubs (tape-lift method). SEM/WDX analyses for GSR were carried out in three steps: the first step was map analysis for barium (Ba) to search for GSR particles from lead styphnate primed ammunition, or tin (Sn) to search for GSR particles from mercury fulminate primed ammunition. The second step was determination of the location of GSR particles by X-ray imaging of Ba or Sn at a magnification of x 1000-2000 in the SEM, using data of map analysis, and the third step was identification of GSR particles, using WDX spectrometers. Analysis of samples from each primer of a stub took about 3 h. Practical applications were shown for utility of this method. PMID:11451063

Kage, S; Kudo, K; Kaizoji, A; Ryumoto, J; Ikeda, H; Ikeda, N

2001-07-01

23

Phosphorus determination in borophosphosilicate or phosphosilicate glass films on a Si wafer by wavelength dispersive x-ray spectroscopy  

SciTech Connect

In this report, peak shift effects in the SiO{sub 2}/Si(100) system due to chemical bonding are demonstrated. The detailed development of the equations appears in a paper submitted for publication in the Journal of X-ray Spectroscopy. These equations are for the spectral line intensity of Si and P from BPSG films and from the Si in the Si(100) substrate. They are subsequently integrated into two simultaneous equations that can be solved for the phosphorus content and the surface density by a computer program using iterative methods. The general expressions for the BPSG films and the computer program are also applicable to PSG films by setting the boron content to zero. The new procedure was then tested by analysis of a well-defined and carefully prepared set of PSG wafer samples. Preliminary analyses were also made on BPSG wafers. 3 refs., 4 figs., 3 tabs.

Levine, H.S.; Higgins, K.L.

1990-01-01

24

Dispersion properties of x-ray waveguides  

Microsoft Academic Search

We study the propagation of ultrashort pulses in x-ray waveguides (WGs) by addressing the problem of the temporal dispersion. Starting from basic equations, by means of numerical calculation we demonstrate that far from the absorption edges of the WGs the cladding's material dispersion is negligible. However, close to the absorption edge significant dispersion can take place. This behavior could in

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

2006-01-01

25

Application of the wavelength dispersive X-ray fluorescence technique to determine soil fluorine with consideration of iron content in the matrix  

NASA Astrophysics Data System (ADS)

The suitability of the wavelength dispersive X-ray fluorescence (WD-XRF) technique for the quantitative analysis of fluorine in soil was assessed in this study. Fluorine standards for WD-XRF calibration with soil matrices consisting of SiO2, Al2O3, Fe2O3, and CaO were prepared by varying the concentrations of CaF2 as a source of fluorine. Based on the standard calibration, the limits of detection and quantification were calculated as 812 and 2690 mg-F/kg-solid (or 1.62 and 5.39 mg-F in absolute mass term), respectively. In addition, the fluorine intensities of the standard samples with high iron content increased significantly compared to those with low iron content. Because of proximity between F-K? and Fe-L? line, the higher iron content preferably helped increase background fluorine intensities. As a means to compensate for the iron interference effect in fluorine analysis, the correction factor (CF) (0.0045) was derived based on the slope ratios between the measured X-ray intensity at the Bragg angle of 43.174° and iron content in the standard sample. The soil fluorine concentration determined by WD-XRF after the CF adjustment exhibited a significantly high correlation with that of the classical alkali fusion-ISE analysis. These findings clearly demonstrated that the WD-XRF technique is reliable enough to allow an easy, precise, and rapid quantitative determination of fluorine in a solid sample (such as iron-bound soil) compared to conventional methods.

An, Jinsung; Kim, Ki-Hyun; Yoon, Hye-On; Seo, Jungju

26

Film calibration for soft x-ray wavelengths  

Microsoft Academic Search

The response of photographic film to X-rays from laser- plasma is of practical interest. Film is often used for the ultimate detection of x-rays in crystal and grating spectrometers and in imaging instruments such as pinhole cameras largely because of its high spatial resolution (approximately 1 - 10 microns). Characteristic curves for wavelengths--3 nm and 23 nm are presented for

Gregory J. Tallents; J. Krishnan; L. Dwivedi; David Neely; I. C. Edmund Turcu

1997-01-01

27

Low Power X-Ray Tube for Use in Energy Dispersive X-Ray Fluorescence Analysis.  

National Technical Information Service (NTIS)

A low power X-ray tube with thin molybdenum transmission target for use in energy dispersive X-ray fluorescence (ENDXRF) element analysis has been indigenously built, along with its power supply. The X-ray tube has been in operation since August 1979, and...

S. K. Kataria R. Govil M. Lal

1980-01-01

28

Energy dispersive X-ray spectroscopy with microcalorimeters  

NASA Astrophysics Data System (ADS)

Shrinking feature sizes in semiconductor device production as well as the use of new materials demand innovation in device technology and material analysis. X-ray spectrometers based on superconducting sensor technology are currently closing the gap between fast energy dispersive spectroscopy (EDS) and high-resolution wavelength dispersive spectroscopy (WDS). This work reports on the successful integration of iridium/gold transition edge sensors in the first industrially used microcalorimeter EDS. The POLARIS microcalorimeter system is installed at the failure analysis lab FA5 at Infineon Technologies AG in Neuperlach (Munich) and is used in routine analysis.

Hollerith, C.; Wernicke, D.; Bühler, M.; Feilitzsch, F. V.; Huber, M.; Höhne, J.; Hertrich, T.; Jochum, J.; Phelan, K.; Stark, M.; Simmnacher, B.; Weiland, W.; Westphal, W.

2004-03-01

29

Introduction to Energy-Dispersive X-Ray Fluorescence Analysis.  

National Technical Information Service (NTIS)

The physical principles of energy dispersive x-ray fluorescence analysis are discussed. A phenomenological description of atomic excitation and the subsequent radiation of x rays on which the physical principles are built, is presented. The atomic shell s...

D. C. Camp

1978-01-01

30

Introduction to energy-dispersive x-ray fluorescence analysis  

Microsoft Academic Search

The physical principles of energy dispersive x-ray fluorescence analysis are discussed. A phenomenological description of atomic excitation and the subsequent radiation of x rays on which the physical principles are built, is presented. The atomic shell structure and nomenclature, x-ray nomenclature and energies, x-ray intensities and fluorescence yields, and a brief description of the competing Auger and Coster-Kronig transitions are

1978-01-01

31

Film calibration for soft x-ray wavelengths  

NASA Astrophysics Data System (ADS)

The response of photographic film to X-rays from laser- plasma is of practical interest. Film is often used for the ultimate detection of x-rays in crystal and grating spectrometers and in imaging instruments such as pinhole cameras largely because of its high spatial resolution (approximately 1 - 10 microns). Characteristic curves for wavelengths--3 nm and 23 nm are presented for eight x-ray films (Kodak 101-01, 101-07, 104-02, Kodak Industrex CX, Russian UF-SH4, UF-VR2, Ilford Q plates and Shanghai 5F film). The calibrations were obtained from the emission of laser-produced carbon plasmas and a Ne-like Ge X-ray laser.

Tallents, Gregory J.; Krishnan, J.; Dwivedi, L.; Neely, David; Turcu, I. C. Edmund

1997-10-01

32

Large area quantitative X-ray mapping of (U,Pu)O 2 nuclear fuel pellets using wavelength dispersive electron probe microanalysis  

NASA Astrophysics Data System (ADS)

The work presented is an example of how large area compositional mapping (?1 mm 2) can be used to provide quantitative information on element distribution and specimen homogeneity. High-resolution was accomplished by producing a collage of X-ray maps acquired using classical conditions; magnification ×400, spatial resolution 256×256 pixels. The individual images, each measuring roughly 250×250 ?m, were converted to quantitative maps using the HIMAX® software package and the XMAS® matrix correction from SAMx. The quantitative gray-level large area X-ray picture was pieced together using the 'Multiple Image Alignment' function of the ANALYSIS® image processing software. This software was also used to convert the gray-level pictures to false color images. The specimens investigated were transverse sections of MOX fuel pellets. Results are presented for the distribution of Pu by area fraction and cumulative area fraction, the size distribution of regions of high Pu concentration and average separation of these regions.

Brémier, S.; Haas, D.; Somers, J.; Walker, C. T.

2003-04-01

33

Short wavelength nickel-like x-ray laser development  

SciTech Connect

Ni-like x-ray lasers have been produced at wavelengths near to, and below the carbon K edge (43.76-{Angstrom}). Recent work has concentrated on the development of the Ni-like Ta amplifier at 44.83-{Angstrom}. Amplification occurs in a laser produced plasma created by irradiating a thin foil of Ta with two beams of the Nova laser. Up to 8 gainlengths have been demonstrated so far, with a gain coefficient of 3.2 cm{sup {minus}1} and a gain duration of 250 psec. The wavelength of 44.83-{Angstrom} is close to optimal for holographic imaging of live cells. It remains to optimize the coherent output power of the amplifier to use it as a source for future x-ray holography experiments. 19 refs., 10 figs., 2 tabs.

MacGowan, B.J.; Da Silva, L.B.; Fields, D.J.; Fry, A.R.; Keane, C.J.; Koch, J.A.; Matthews, D.L.; Maxon, M.S.; Mrowka, S.; Osterheld, A.L.; Scofield, J.H.; Shimkaveg, G.

1991-01-07

34

Site-specific Incorporation of 3-Iodo-L-tyrosine into Proteins and Single-wavelength Anomalous Dispersion Phasing with Soft X-ray in Protein Crystallography  

NASA Astrophysics Data System (ADS)

Iodine is a good anomalous scatter for radiations from in-house X-ray generators (Cu/CrK?). Non-natural amino acid, 3-iodo-L-tyrosine, is able to be site-specifically incorporated into proteins with amber suppresser tRNA and mutated TyrRS from M. jannaschii in the E. coli expression system. To determine the crystal structure of acetyl transferase from T. thermophilus, iodotyrosine-containing proteins were prepared and crystallized. Structure determination was successfully conducted with the protein variant with iodotyrosine at position 111. Anomalous signals from iodotyrosine with Cu/CrK? radiations were both sufficient to calculate clear electron density map. In the crystal structure, iodotyrosine did not significantly disturb the native structure.

Murayama, Kazutaka; Sakamoto, Kensaku

35

Plasma dispersion in ultrashort-pulse x-ray lasers  

Microsoft Academic Search

The effect of plasma dispersion in longitudinally pumped x-ray lasers prepared by optical-field-induced ionization is investigated. Dispersion is shown to bound the x-ray peak intensity along the laser and to stretch the pulse in time, thus coincidentally giving a saturated output energy fluence that increases linearly with laser length as in the nondispersive regime. High output efficiencies [eta][gt]10[sup [minus]4] in

Peter Amendt; David C. Eder; Richard A. London; Mordecai D. Rosen

1993-01-01

36

The use of wavelength dispersive X-ray fluorescence and discriminant analysis in the identification of the elemental composition of cumin samples and the determination of the country of origin.  

PubMed

Sixteen elements found in 33 cumin spice samples from China, India, Syria, and Turkey were analysed by wavelength dispersive X-ray fluorescence (WDXRF) spectroscopy using the commercially available Bruker - AXS S4 Explorer for the purpose of using the elements to discriminate among country of origin. Pellets were prepared of the samples and elemental concentrations calculated from calibration curves constructed using four National Institute of Standards and Technology (NIST) standards. A separate NIST tomato standard (1573a) was used as a validation check, while the WDXRF data for six of the cumin samples was further validated using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The elements measured included Ca, Mg, K, P, S, Al, Ba, Br, Cl, Fe, Na, Mn, Rb, Sr, Cu, and Zn and were detected in the range from an average mean of 4.3 mg kg(-1) for Ba up to 19223.8 mg kg(-1) for K. Analysis of variance (ANOVA) was used to determine which elemental concentrations were statistically different from one another, and discriminant analysis was used to classify the cumin samples by country of origin. Using only eight elements (Ca, Mg, K, Fe, Na, Mn, Sr, and Zn) we were able to differentiate among cumin samples from four different geographic origins. Validation of the model with the validation set yielded 87.50% accuracy. Successful discrimination with just eight elements will allow for higher throughput in the screening of cumin samples using WDXRF for origin verification in less time. PMID:22980878

Hondrogiannis, E; Peterson, K; Zapf, C M; Roy, W; Blackney, B; Dailey, K

2012-07-10

37

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

PubMed

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

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

2012-07-31

38

Single atom identification by energy dispersive x-ray spectroscopy  

SciTech Connect

Using aberration-corrected scanning transmission electron microscope and energy dispersive x-ray spectroscopy, single, isolated impurity atoms of silicon and platinum in monolayer and multilayer graphene are identified. Simultaneously acquired electron energy loss spectra confirm the elemental identification. Contamination difficulties are overcome by employing near-UHV sample conditions. Signal intensities agree within a factor of two with standardless estimates.

Lovejoy, T. C.; Dellby, N.; Krivanek, O. L. [Nion, 1102 8th St., Kirkland, Washington 98033 (United States); Ramasse, Q. M. [SuperSTEM Laboratory, STFC Daresbury, Keckwick Lane, Daresbury WA4 4AD (United Kingdom); Falke, M.; Kaeppel, A.; Terborg, R. [Bruker Nano GmbH, Schwarzschildstr. 12, 12489 Berlin (Germany); Zan, R. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

2012-04-09

39

Curved crystal X-ray optics for a new type of high speed, multiwavelength dispersive X-ray reflectometer  

Microsoft Academic Search

As the key element of a new type of high speed, multiwavelength dispersive X-ray reflectometer, the performance of a curved crystal optical system having an extremely small radius of curvature was studied by realizing and characterizing a convergent X-ray beam that has a one-to-one correlation between its energy and direction. Such an X-ray beam covered an energy range of 8-45

Tadashi Matsushita; Yasuhiro Inada; Yasuhiro Niwa; Masashi Ishii; Kenji Sakurai; Masaharu Nomura

2007-01-01

40

Wavelength tunable diffractive transmission lens for hard x rays  

Microsoft Academic Search

We report on the fabrication and testing of linear transmission Fresnel zone plates for hard x rays. The diffractive elements are generated by electron beam lithography and chemical wet etching of oriented silicon substrates. By tilting the cylindrical lenses with respect to the x-ray beam, the effective path through the phase shifting zones can be varied. This makes it possible

C. David; B. Nöhammer; E. Ziegler

2001-01-01

41

A Diffraction System with an X-ray Beam of a Band of Wavelengths  

SciTech Connect

New diffraction system has been constructed at the Synchrotron Radiation Center at Ritsumeikan University, in which a parallel X-ray beam of a band of wavelengths is produced by reflection from a multilayer monochromator of depth-graded thicknesses. The band width is 0.013 nm and the useful wavelength range is from 0.16 nm to 0.20 nm. Diffraction patterns were taken from a single crystal of an enantiomorphous ferrocene-derivative compound employing an Imaging Plate as a detector. Bragg reflections are seen elongated with a characteristic intensity profile due to anomalous dispersion. Bijvoet pair of reflections show a clear difference in the profile on the short wavelength side of the absorption edge and distinction between the enantiomers can be made more easily than the classical method based on the comparison of integrated intensities.

Koganezawa, T.; Iwasaki, H.; Yoshimura, Y.; Nakamura, N. [Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan); Shoji, T. [X-ray Research Laboratory, RIGAKU Coorporation, Takatsuki, Osaka 569-1146 (Japan)

2004-05-12

42

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

SciTech Connect

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

Worley, Christopher G [Los Alamos National Laboratory

2009-01-01

43

A dual-channel, focusing x-ray spectrograph with uniform dispersion for Z pinch plasmas measurement  

SciTech Connect

A dual-channel, focusing x-ray spectrograph with uniform dispersion (i.e., the linear dispersion of this spectrograph is a constant) is described for measuring the x-ray spectra emission from the hot, dense Al Z pinch plasmas. The spectrograph uses double uniform-dispersed crystals (e.g., a Quartz 1010 crystal and a Mica 002 crystal) as dispersion elements and a double-film box as detector to achieve the simultaneous recording of the time integrated spectrum covering a wide spectral range of {approx}5-9 A. Since this spectrograph disperse the x-rays on the detector plane with uniform spacing for every wavelength, it needs not the calibration of the wavelength with spatial coordinate, thereby own the advantages of easiness and veracity for spectra identification. The design of this spectrograph and the example of experiment on the ''Yang'' accelerator are presented.

Yang Qingguo; Li Zeren; Chen Guanhua; Ye Yan; Huang Xianbin; Cai Hongchun; Li Jing [Institute of Fluid Physics, CAEP, Mianyang, Sichuan 621900 (China); Xiao Shali [Key Laboratory of Optic-electronic Technology and System, Ministry of Education, Chongqing University, Chongqing 400044 (China)

2012-01-15

44

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

SciTech Connect

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

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

2008-09-24

45

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

SciTech Connect

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

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

2007-08-24

46

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

DOEpatents

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

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

1985-01-01

47

Synchrotron energy-dispersive X-ray diffraction tomography  

NASA Astrophysics Data System (ADS)

Energy-dispersive diffraction tomography using white-beam synchrotron X-rays with energies up to 140keV yields images of the interior features of solid objects up to 50mm thick. The volume sampled is determined by the geometry of the diffracting lozenge defined by the incident beam, the detector system collimation and the Bragg angle. Using conventional beam slits to form a highly collimated 50?mx50?m incident beam and a 40?m collimator aperture, we demonstrate on a PEEK phantom that a lateral resolution (transverse to the beam direction) of a few microns can be achieved. The resolution in the direction of the incident beam is necessarily poorer than this since the diffracting lozenge is elongated in this direction, with length increasing rapidly at small angles. There is no evidence of significant contamination of the diffracted intensity by the effects of multiple scattering from outside the primary lozenge.

Hall, C.; Barnes, P.; Cockcroft, J. K.; Colston, S. L.; Häusermann, D.; Jacques, S. D. M.; Jupe, A. C.; Kunz, M.

1998-04-01

48

Solid-State Energy-Dispersion Spectrometer for Electron-Microprobe X-ray Analysis  

Microsoft Academic Search

Improved lithium-drifted silicon solid-state detectors allow detection and energy dispersion of x-rays of about 3 to 30 kiloelectron volts in the electronmicroprobe x-ray analyzer. Energy resolution is sufficient to separate peaks of characteristic x-rays of elements adjacent in the periodic system at atomic number 20 and higher. The detected x-ray spectrum emitted from an unknown sample can be recorded with

Ray Fitzgerald; Klaus Keil; Kurt F. J. Heinrich

1968-01-01

49

Deep X-ray lithography with a tunable wavelength shifter at CAMD.  

PubMed

An additional X-ray lithography facility is under construction at the Center for Advanced Microstructures and Devices. It will receive radiation from a 7.5 T superconducting three-pole wavelength shifter. The critical energy of the insertion device is tunable up to a maximum value of 11.2 keV, allowing for optimization of photon spectra to resist thickness. In particular, this hard X-ray source will allow investigation of X-ray lithography at very high energies for devices with thicknesses in excess of 1 mm, and study of low-cost mass-production concepts, using simultaneously exposed stacks of resist layers. PMID:15263757

Khan Malek, C; Saile, V; Manohara, H; Craft, B

1998-05-01

50

Is scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) quantitative?  

PubMed

Scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) is a widely applied elemental microanalysis method capable of identifying and quantifying all elements in the periodic table except H, He, and Li. By following the "k-ratio" (unknown/standard) measurement protocol development for electron-excited wavelength dispersive spectrometry (WDS), SEM/EDS can achieve accuracy and precision equivalent to WDS and at substantially lower electron dose, even when severe X-ray peak overlaps occur, provided sufficient counts are recorded. Achieving this level of performance is now much more practical with the advent of the high-throughput silicon drift detector energy dispersive X-ray spectrometer (SDD-EDS). However, three measurement issues continue to diminish the impact of SEM/EDS: (1) In the qualitative analysis (i.e., element identification) that must precede quantitative analysis, at least some current and many legacy software systems are vulnerable to occasional misidentification of major constituent peaks, with the frequency of misidentifications rising significantly for minor and trace constituents. (2) The use of standardless analysis, which is subject to much broader systematic errors, leads to quantitative results that, while useful, do not have sufficient accuracy to solve critical problems, e.g. determining the formula of a compound. (3) EDS spectrometers have such a large volume of acceptance that apparently credible spectra can be obtained from specimens with complex topography that introduce uncontrolled geometric factors that modify X-ray generation and propagation, resulting in very large systematic errors, often a factor of ten or more. PMID:22886950

Newbury, Dale E; Ritchie, Nicholas W M

2012-08-09

51

Development of in situ, at-wavelength metrology for soft x-ray nano-focusing  

SciTech Connect

At the Advanced Light Source (ALS), we are developing broadly applicable, high-accuracy, in situ, at-wavelength wavefront slope measurement techniques for Kirkpatrick-Baez (KB) mirror nano-focusing. We describe here details of the metrology beamline endstation, the at-wavelength tests, and an original alignment method that have already allowed us to precisely set a bendable KB mirror to achieve a FWHM focused spot size of ~;;120 nm, at 1-nm soft x-ray wavelength.

Yuan, Sheng Sam; Yashchuk, Valeriy V.; Goldberg, Kenneth A.; Celestre, Richard; McKinney, Wayne R.; Morrison, Gregory Y.; Warwick, Tony; Padmore, Howard A.

2010-09-19

52

Development of in situ, at-wavelength metrology for soft X-ray nano-focusing  

NASA Astrophysics Data System (ADS)

At the Advanced Light Source (ALS), we are developing broadly applicable, high-accuracy, in situ, at-wavelength wavefront slope measurement techniques for Kirkpatrick-Baez (KB) mirror nano-focusing. We describe here details of the metrology beamline endstation, the at-wavelength tests, and an original alignment method that have already allowed us to precisely set a bendable KB mirror to achieve a FWHM focused spot size of ˜120 nm, at 1 nm soft X-ray wavelength.

Yuan, Sheng; Yashchuk, Valeriy V.; Goldberg, Kenneth A.; Celestre, Richard; McKinney, Wayne R.; Morrison, Gregory Y.; Warwick, Tony; Padmore, Howard A.

2011-09-01

53

Soft x-ray phase modulation multilayer dispersive element  

Microsoft Academic Search

Multilayer phase gratings have higher diffraction efficiency than amplitude gratings in the soft x-ray region. The authors give a detailed description of the fabrication, characterization, and performance of soft x-ray phase modulation multilayer laminar gratings. The experimental results are discussed and compared with theory.

Lixiang Yuan; Zhengxiu Fan; Mingqi Cui; Shaojun Fu

1995-01-01

54

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

NASA Astrophysics Data System (ADS)

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

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

2005-07-01

55

Direct index of refraction measurements at extreme-ultraviolet and soft-x-ray wavelengths  

SciTech Connect

Coherent radiation from undulator beamlines has been used to directly measure the real and imaginary parts of the index of refraction of several materials at both extreme-ultraviolet and soft-x-ray wavelengths. Using the XOR interferometer, we measure the refractive indices of silicon and ruthenium, essential materials for extreme-ultraviolet lithography. Both materials are tested at wavelength (13.4 nm) and across silicon's L2(99.8 eV) and L3(99.2 eV) absorption edges. We further extend this direct phase measurement method into the soft-x-ray region, where measurements of chromium and vanadium are performed around their L3absorption edges at 574.1 and 512.1 eV, respectively. These are the first direct measurements, to our knowledge, of the real part of the index of refraction made in the soft-x-ray region.

Rosfjord, Kristine; Chang Chang; Miyakawa, Ryan; Barth, Holly; Attwood, David

2006-03-10

56

Energy-dispersive X-ray fluorescence analysis with pyrographite crystals and small X-ray tubes  

Microsoft Academic Search

The advantages and peculiarities are described of energy-dispersive X-ray fluorescence analysis with preliminary energy selection\\u000a of the radiation coming from a sample with the help of a cylindrical system of pyrographite crystals. The results of application\\u000a of this method to the analysis of U and transuranium elements in the solutions of spent nuclear fuel reprocessing are presented.\\u000a Minimum detectable concentration

V. V. Berdikov; O. I. Grigor'ev; B. S. Iokhin

1980-01-01

57

Wavelength choice for soft x-ray laser holography of biological samples  

Microsoft Academic Search

The choice of an optimal wavelength for soft x-ray holography is discussed, based on a description of scattering by biological structures within an aqueous environment. We conclude that wavelengths slightly longer than the 43.7 A carbon K-edge provide a good trade off between minimizing the necessary source power and the dose absorbed by the sample and maximizing the penetrability of

Richard A. London; Mordecai D. Rosen; James E. Trebes

1989-01-01

58

Diffraction peaks restoration and extraction in energy dispersive X-ray diffraction  

Microsoft Academic Search

This paper proposes a method to restore energy dispersive X-ray diffraction (EDXRD) spectra and to extract diffraction peaks. It follows a maximum a posteriori approach using a physical model of the formation of the EDXRD data to remove blur caused by both the detector and the coarse angular resolution of X-ray tube based EDXRD setup. It separates peaks due to

Ferréol Soulez; Charles Crespy; Valérie Kaftandjian; Philippe Duvauchelle

2011-01-01

59

X-ray nanofocusing using a piezoelectric deformable mirror and at-wavelength metrology methods  

NASA Astrophysics Data System (ADS)

An adaptive X-ray mirror with shape controllability in a spatial wavelength range longer than 20 mm was developed, and we demonstrated its shape generation and focusing performance characteristics. The shape accuracy in a spatial wavelength range shorter than 20 mm, which cannot be adaptively figured, was controlled in advance offline. A pencil beam method for measuring the slope error and a phase retrieval method for precisely estimating the wavefront error were employed for online shape correction. A focal spot size of 120 nm, which is diffraction-limited, was realized, and the shape accuracy obtained nearly satisfied Rayleigh's quarter-wavelength criterion.

Nakamori, Hiroki; Matsuyama, Satoshi; Imai, Shota; Kimura, Takashi; Sano, Yasuhisa; Kohmura, Yoshiki; Tamasaku, Kenji; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

2013-05-01

60

Internal conversion in energy dispersive X-ray analysis of actinide-containing materials.  

PubMed

The use of X-ray elemental analysis tools like energy dispersive X-ray (EDS) is described in the context of the investigation of nuclear materials. These materials contain radioactive elements, particularly alpha-decaying actinides that affect the quantitative EDS measurement by producing interferences in the X-ray spectra. These interferences originating from X-ray emission are the result of internal conversion by the daughter atoms from the alpha-decaying actinides. The strong interferences affect primarily the L X-ray lines from the actinides (in the typical energy range used for EDS analysis) and would require the use of the M lines. However, it is typically at the energy of the actinide's M lines that the interferences are dominant. The artifacts produced in the X-ray analysis are described and illustrated by some typical examples of analysis of actinide-bearing material. PMID:17490502

Wiss, Thierry; Thiele, Hartmut; Cremer, Bert; Ray, Ian

2007-06-01

61

A High Resolving Power, Curved-Crystal Focusing Spectrometer for Short Wave-Length X-Rays and Gamma-Rays  

Microsoft Academic Search

Description is given of a transmission-type, curved-crystal focusing spectrometer for short wave-length x-rays, and gamma-rays having a dispersion of 1.186 x.u. per mm at short wave-lengths. The spectrometer utilizes the (310) planes of quartz in a crystalline plate of dimensions 80×70×1.0 mm curved cylindrically to a radius of two meters. High luminosity is obtained since the useful aperture in the

Jesse W. M. DuMond

1947-01-01

62

Calibration of Energy Dispersive X-Ray Spectrometers for Analysis of Thin Environmental Samples.  

National Technical Information Service (NTIS)

Four separate techniques for calibrating energy dispersive x-ray spectrometers are described. They include the use of (1) individual evaporated elemental thin-film standards, (2) nebulized multielement standard solution deposits to determine relative elem...

R. D. Giauque R. B. Garrett L. Y. Goda

1976-01-01

63

Compositional analysis of Ceramic Glaze by Laser Induced Breakdown Spectroscopy and Energy Dispersive X-Ray  

NASA Astrophysics Data System (ADS)

Laser induced breakdown spectroscopy (LIBS) has been applied for the analysis of Egyptian Islamic glaze ceramic sample. The sample dating back to Fatimid period (969-1169AD), and collected from Al-Fustat excavation store in Cairo. The analysis of contaminated pottery sample has been performed to draw mapping for the elemental compositions by LIBS technique. LIBS measurements have been done by the fundamental wavelength (1064 nm) of Nd: YAG laser for the elemental analysis and performing the cleaning processes of the pottery sample. In addition, complementary analyses were carried out by scanning electron microscopy linked with energy dispersive X-ray microanalysis (SEM/EDX) to obtain verification of chemical results. The morphological surfaces before and after cleaning has been done by Optical Microscopy (OM).

Khedr, A.; Abdel-Kareem, O.; Elnabi, S. H.; Harith, M. A.

2011-09-01

64

Towards shorter wavelength x-ray lasers using a high power, short pulse pump laser  

SciTech Connect

A near-terawatt, KrF* laser system, focussable to power densities >10{sup 18} W/cm{sup 2} has been constructed for use as a pump laser in various schemes aimed at the development of x-ray lasing below 5nm. The laser system along with output characteristics such as the pulse duration, the focal spot size, and the percentage of amplified spontaneous emission (ASE) emitted along with the laser pulse will be presented. Schemes intended to lead to shorter wavelength x-ray emission will be described. The resultant requirements on the pump laser characteristics and the target design will be outlined. Results from recent solid target experiments and two-laser experiments, showing the interaction of a high-power, short pulse laser with a preformed plasma, will be presented. 13 refs., 5 figs.

Tighe, W.; Krushelnick, K.; Valeo, E.; Suckewer, S.

1991-05-01

65

Energy dispersive X-ray diffraction to identify explosive substances: Spectra analysis procedure optimization  

Microsoft Academic Search

To detect the presence of explosives in packages, automated systems are required. Energy dispersive X-ray diffraction (EDXRD) represents a powerful non-invasive tool providing information on the atomic structure of samples. In this paper, EDXRD is investigated as a suitable technique for explosive detection and identification. To this end, a database has been constructed, containing measured X-ray diffraction spectra of several

C. Crespy; P. Duvauchelle; V. Kaftandjian; F. Soulez; P. Ponard

2010-01-01

66

Modelling an Energy-Dispersive X-Ray Diffraction System for Drug Detection  

Microsoft Academic Search

A system for drug detection using X-ray diffraction is currently being developed by the DILAX collaboration. A simulation program for modelling the response of an energy-dispersive X-ray diffraction system has been developed, with the two-fold aim of selecting possible configurations prior to experimental tests and of generating data for statistical models for prediction of drug content. Simulated data showed a

Silvia Pani; Emily Cook; Julie Horrocks; Leah George; Sheila Hardwick; Robert Speller

2009-01-01

67

Strain field and scattered intensity profiling with energy dispersive x-ray scattering  

Microsoft Academic Search

Two powerful synchrotron x-ray scattering techniques for residual strain depth-profiling and tomography-like scatter-intensity profiling of materials are presented. The techniques utilize energy dispersive x-ray scattering, from a fixed microvolume, with microscanning of the specimen being used to profile its interior. The tomography-like profiles exploit scattering-cross-section variations, and can be contrast enhanced by separately monitoring scattering from different crystal structures. The

M. Croft; I. Zakharchenko; Z. Zhong; Y. Gurlak; J. Hastings; J. Hu; R. Holtz; M. Dasilva; T. Tsakalakos

2002-01-01

68

X-ray polaroids based on the total external reflection in anomalous-dispersion regions  

NASA Astrophysics Data System (ADS)

A new method of development of x-ray polaroids is suggested. The idea is based on the effect of total external reflection from an anisotropic crystal in the anomalous-dispersion region. The polarization coefficient for hexagonal BN crystal near the boron K absorption edge is calculated for different glancing angles and thicknesses of sample. It is shown that the method treated provides a simple way of constructing an effective x-ray polaroid.

Machavariani, V. Sh

1996-12-01

69

Development of a prototype pipework scanning system based upon energy dispersive X-ray diffraction (EDXRD)  

Microsoft Academic Search

A prototype pipework scanning system based upon energy dispersive X-ray diffraction (EDXRD) has been produced, for which system development and preliminary results are presented here. This apparatus has been developed from experience with 2D and 3D bench-top EDXRD systems and comprises a conventional industrial X-ray tube coupled to a bespoke design of tungsten collimators and compact CdTe detector. It is

D. J. Garrity; A. J. De Rosa; D. A. Bradley; S. E. Jarman; P. M. Jenneson; S. M. Vincent

2010-01-01

70

Dispersive spread of virtual sources by asymmetricX-ray monochromators  

SciTech Connect

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

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

2012-01-26

71

Quantum efficiency of cesium iodide photocathodes at soft x-ray and extreme ultraviolet wavelengths  

SciTech Connect

We have measured the quantum efficiency for normal incidence radiation of microchannel plate detectors which use opaque or semitransparent photocathodes made of fluffy CsI, solid CsI, or both. At wavelengths below --44 A-circle, detectors with fluffy CsI semitransparant photocathodes are more efficient than those with opaque photocathodes of silid CsI, but the opposite is true at longer wavelengths. Fluffy CsI semitransparent photocathodes with surface densities between 150 and 400 ..mu..m/cm/sup 2/ are optimum at soft x-ray wavelengths, and we have obtained efficiencies of 35 and 41% at 8 and 44A-circle, respectively, for a single-layer photocathode. The measured peak efficiency for an opaque layer of solid CsI, deposited at O/sup 0/ coating angle and 5000 A-circle (226 ..-->..g/cm/sub 2/) in thickness, is 56% at 110 A-circle.

Kowalski, M.P.; Fritz, G.G.; Cruddace, R.G.; Unzicker, A.E.; Swanson, N.

1986-07-15

72

Ultrasoft X-Ray Bragg and Specular Reflection: The Effects of Anomalous Dispersion.  

National Technical Information Service (NTIS)

The objective of this work has been twofold: first, to test a method for quantitatively predicting the atomic scattering factors in the sensitive, anomalous dispersion, low energy x-ray region as based upon semi-classical dispersion theory in which theore...

B. L. Henke R. C. Perera R. H. Ono

1974-01-01

73

X-ray photoemission and energy dispersive spectroscopy of hydroxyapatite-coated titanium  

SciTech Connect

The purpose of this study was to determine the chemical composition changes of hydroxyapatite (HA) coated titanium using surface analysis (X-ray photoemission) and bulk analysis (energy dispersive spectroscopy). The specimens examined were controls and specimens aged 30 min and 3 h at room temperature in distilled water and 0.2M sodium phosphate buffer (pH 7.2). Each X-ray photoemission cycle consisted of three scans followed by argon sputtering for 10 min for usually 20 cycles, corresponding to a sampling depth of {approximately}1,500 {angstrom}. The energy dispersive spectroscopy analysis was on a 110 by 90 {micro}m area for 500 s. The X-ray photoemission results indicated the oxidation effect of water on the titanium (as TiO{sub 2}) and the effect of the buffer to increase the surface concentration of phosphorus. No differences in the chemical composition were observed by energy dispersive spectroscopy analysis.

Drummond, J.L.; Steinberg, A.D. [Univ. of Illinois, Chicago, IL (United States). Coll. of Dentistry; Krauss, A.R. [Argonne National Lab., IL (United States)

1997-07-01

74

Development of at-wavelength metrology for x-ray optics at the ALS  

SciTech Connect

The comprehensive realization of the exciting advantages of new third- and forth-generation synchrotron radiation light sources requires concomitant development of reflecting and diffractive x-ray optics capable of micro- and nano-focusing, brightness preservation, and super high resolution. The fabrication, tuning, and alignment of the optics are impossible without adequate metrology instrumentation, methods, and techniques. While the accuracy of ex situ optical metrology at the Advanced Light Source (ALS) has reached a state-of-the-art level, wavefront control on beamlines is often limited by environmental and systematic alignment factors, and inadequate in situ feedback. At ALS beamline 5.3.1, we are developing broadly applicable, high-accuracy, in situ, at-wavelength wavefront measurement techniques to surpass 100-nrad slope measurement accuracy for Kirkpatrick-Baez (KB) mirrors. The at-wavelength methodology we are developing relies on a series of tests with increasing accuracy and sensitivity. Geometric Hartmann tests, performed with a scanning illuminated sub-aperture determine the wavefront slope across the full mirror aperture. Shearing interferometry techniques use coherent illumination and provide higher sensitivity wavefront measurements. Combining these techniques with high precision optical metrology and experimental methods will enable us to provide in situ setting and alignment of bendable x-ray optics to realize diffraction-limited, sub 50 nm focusing at beamlines. We describe here details of the metrology beamline endstation, the x-ray beam diagnostic system, and original experimental techniques that have already allowed us to precisely set a bendable KB mirror to achieve a focused spot size of 150 nm.

Yashchuk, Valeriy V.; Goldberg, Kenneth A.; Yuan, Sheng; Celestre, Richard; McKinney, Wayne R.; Morrison, Gregory; Warwick, Tony; Padmore, Howard A.

2010-07-09

75

Imaging at soft X-ray wavelengths with high-gain microchannel plate detector systems  

NASA Astrophysics Data System (ADS)

Multianode microchannel array (MAMA) detector systems with formats of 256 x 1024 pixels and active areas of 6 x 26 mm are now under evaluation at visible, UV and soft X-ray wavelengths. Very-large-format versions of the MAMA detectors with formats of 2048 x 2048 pixels and active areas of 52 x 52 mm are under development for use in the NASA Goddard Space Telescope Imaging Spectrograph (STIS). Open-structure versions of these detectors with Cs I photocathodes can provide a high-resolution imaging capability at EUV and soft X-ray wavelengths and can deliver a maximum count rate from each array in excess of 10 to the 6th counts/s. In addition, these detector systems have the unique capability to determine the arrival time of a detected photon to an accuracy of 100 ns or better. The construction, mode of operation, and performance characteristics of the MAMA detectors are described, and the program for the development of the very-large-format detectors is outlined.

Timothy, J. Gethyn

1986-01-01

76

At-wavelength figure metrology of hard x-ray focusing mirrors  

SciTech Connect

We have developed an at-wavelength wave-front metrology of a grazing-incidence focusing optical systems in the hard x-ray region. The metrology is based on numerical retrieval from the intensity profile around the focal point. We demonstrated the at-wavelength metrology and estimated the surface figure error on a test mirror. An experiment for measuring the focusing intensity profile was performed at the 1-km-long beamline (BL29XUL) of SPring-8. The obtained results were compared with the profile measured using an optical interferometer and were confirmed to be in good agreement with it. This technique is a potential method of characterizing wave-front aberrations on elliptical mirrors for sub-10-nm focusing.

Yumoto, Hirokatsu; Mimura, Hidekazu; Matsuyama, Satoshi; Handa, Soichiro; Sano, Yasuhisa; Yabashi, Makina; Nishino, Yoshinori; Tamasaku, Kenji; Ishikawa, Tetsuya; Yamauchi, Kazuto [Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); SPring-8/Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 Japan (Japan); SPring-8/RIKEN, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Department of Precision Science and Technology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2006-06-15

77

Metastable phase diagram of Bi probed by single-energy x-ray absorption detection and angular dispersive x-ray diffraction  

Microsoft Academic Search

In this paper we report the results of a detailed experimental study of samples composed of micrometric Bi droplets providing an insight into the metastable phase diagram of Bi. To this purpose we have used the single-energy x-ray absorption detection technique in combination with angular dispersive x-ray diffraction available at the BM29 beamline of the European Synchrotron Radiation Facility. This

E. Principi; M. Minicucci; A. Di Cicco; A. Trapananti; S. De Panfilis; R. Poloni

2006-01-01

78

Using angular dispersion and anomalous transmission to shape ultramonochromatic x rays  

SciTech Connect

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

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

2011-11-15

79

Tunable coherent radiation at soft X-ray wavelengths: Generation and interferometric applications  

SciTech Connect

The availability of high power, spectrally and spatially coherent soft x-rays (SXR) would facilitate a wide variety of experiments as this energy region covers the primary resonances of many magnetic and biological materials. Specifically, there are the carbon and oxygen K-edges that are critical for biological imaging in the water window and the L-edges of iron, nickel, and cobalt for which imaging and scattering studies can be performed. A new coherent soft X-ray branchline at the Advanced Light Source has begun operation (beamline 12.0.2). Using the third harmonic from an 8 cm period undulator, this branch delivers coherent soft x-rays with photon energies ranging from 200eV to 1keV. This branchline is composed of two sub-branches one at 14X demagnification and the other 8X demagnification. The former is optimized for use at 500eV and the latter at 800eV. Here the expected power from the third harmonic of this undulator and the beamline design and characterization is presented. The characterization includes measurements on available photon flux as well as a series of double pinhole experiments to determine the coherence factor with respect to transverse distance. The first high quality Airy patterns at SXR wavelengths are created with this new beamline. The operation of this new beamline allows for interferometry to be performed in the SXR region. Here an interferometric experiment designed to directly determine the index of refraction of a material under test is performed. Measurements are first made in the EUV region using an established beamline (beamline12.0.1) to measure silicon, ruthenium and tantalum silicon nitride. This work is then extended to the SXR region using beamline 12.0.2 to test chromium and vanadium.

Rosfjord, Kristine Marie

2004-07-01

80

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

NASA Astrophysics Data System (ADS)

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

Zimmer, D.; Ros, D.; Guilbaud, O.; Habib, J.; Kazamias, S.; Zielbauer, B.; Bagnoud, V.; Ecker, B.; Hochhaus, D. C.; Aurand, B.; Neumayer, P.; Kuehl, T.

2010-07-01

81

Quantitative Energy Dispersive X-Ray Spectrometry Using an Emispec Vision System.  

National Technical Information Service (NTIS)

The purpose of this work was to investigate the use of an Emispec Vision system to analyze energy dispersive x-ray spectra (EDS) obtained with the Topcon 002B transmission electron microscope (TEM) in the Materials Science Laboratory at the Naval Postgrad...

C. A. Kasemodel

1999-01-01

82

The energy dispersive X-ray diffraction method: annotated bibliography 1968–78  

Microsoft Academic Search

The present summary is a brief survey of the energy dispersive X-ray diffraction (EDXRD) method and an appraisal of the current position. A comprehensive chronological list of annotated references on EDXRD is given, covering the period 1968 to 1978. An index of authors is appended.

E. Laine; I. Lähteenmäki

1980-01-01

83

Identification of liquid materials using energy dispersive X-ray scattering  

Microsoft Academic Search

Energy dispersive X-ray scattering (EDXRS) has been successfully applied for the identification of liquid materials for the first time. Three liquid systems of primary alcohols, ketones compounds and acids are carefully investigation and the scattering spectra are described. Based on structural and compositional differences of compounds, the scattering profiles of all samples exhibit characteristic shapes, indicating that EDXRS profile is

Yu Zhong; Bai Sun; Daoyang Yu; Wei Li; Yu Zhang; Minqiang Li; Jinhuai Liu

2010-01-01

84

The energy dispersive X-ray diffraction method: annotated bibliography 1968–78  

Microsoft Academic Search

The present summary is a brief survey of the energy dispersive X-ray diffraction (EDXRD) method and an appraisal of the current\\u000a position. A comprehensive chronological list of annotated references on EDXRD is given, covering the period 1968 to 1978.\\u000a An index of authors is appended.

E. Laine; I. Lähteenmäki

1980-01-01

85

New software to model energy dispersive X-ray diffraction in polycrystalline materials  

Microsoft Academic Search

Detection of illicit materials, such as explosives or drugs, within mixed samples is a major issue, both for general security and as part of forensic analyses. In this paper, we describe a new code simulating energy dispersive X-ray diffraction patterns in polycrystalline materials. This program, SinFullscat, models diffraction of any object in any diffractometer system taking all physical phenomena, including

B. Ghammraoui; J. Tabary; S. Pouget; C. Paulus; V. Moulin; L. Verger; Ph. Duvauchelle

86

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

ERIC Educational Resources Information Center

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

Palmer, Peter T.

2011-01-01

87

Study of air pollutants in Hong Kong using energy dispersive X-ray fluorescence  

Microsoft Academic Search

Airborne particulate samples were collected from various reference sites in Hong Kong and the energy dispersive X-ray fluorescence (EDXRF) intensities for 19 chemical elements were recorded. Principal component analysis (PCA) was employed so that the variances of these 19 original variables were captured by a few new indices called principal components or PCs. Data points for similar sources were automatically

A. K. M. Chu; H. H. Cheng; R. C. W. Kwok; K. N. Yu

2003-01-01

88

Strain profiling of fatigue crack overload effects using energy dispersive X-ray diffraction  

Microsoft Academic Search

Synchrotron based energy dispersive X-ray diffraction has been used to profile the strains around fatigue cracks in 4140 steel test specimens. In particular strain field comparisons were made on specimens prepared: with initial constant stress intensity fatigue; with this initial fatigue followed by a single overload cycle; and with this fatigue-overload sequence followed by an additional constant stress intensity fatigue.

M. Croft; Z. Zhong; N. Jisrawi; I. Zakharchenko; R. L. Holtz; J. Skaritka; T. Fast; K. Sadananda; M. Lakshmipathy; T. Tsakalakos

2005-01-01

89

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

SciTech Connect

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

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

2010-07-20

90

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

NASA Astrophysics Data System (ADS)

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

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

2007-01-01

91

Multi-wavelength Observations of Cyg X-3 During a Hard X-ray Flare  

NASA Astrophysics Data System (ADS)

We present the results of multi-wavelength observations of the microquasar Cygnus X-3 which was detected by the Burst Alert Telescope (BAT) onboard the Swift observatory to be in a hard X-ray (10-150 keV) flaring state on March 23, 2012. Since the VERITAS collaboration has initiated a plan to perform follow-up observations of hard X-ray transients detected by the BAT, this event prompted observations with the VERITAS array of imaging atmospheric Cherenkov telescopes on the nights of March 24 and 27, 2012. A significant very high energy (VHE; E>100GeV) signal was not seen from the micro quasar. In addition to the BAT and VERITAS observations, we will present the results of an analysis of Fermi LAT data in the 200 - 300,000 MeV band from the flaring period. Although the exact physics are currently unclear, observations over the entire electromagnetic spectrum can provide insight to the physical phenomena producing the flares.

Perkins, Jeremy S.; Matthews, N. K.; VERITAS Collaboration

2013-04-01

92

Synchrotron radiation energy-dispersive X-ray diffraction analysis of salt distribution in Lepine limestone  

Microsoft Academic Search

We describe an analytical application of synchrotron radiation energy-dispersive diffraction tomography to map the distribu- tion of crystalline sodium sulfate deposited by evaporation from solution within a building limestone. Few techniques are able to provide spatially-resolved analytical information from the interior of opaque objects. An important relatively recent development is the invention of energy-dispersive synchrotron X-ray diffraction tomography EDD-T.1,2 Ac

Ioannis Ioannou; William D. Hoff; Victoria A. Pugsleyb; Simon D. M. Jacquesd

93

Energy-dispersive X-ray absorption spectroscopy at LNLS: investigation on strongly correlated metal oxides.  

PubMed

An energy-dispersive X-ray absorption spectroscopy beamline mainly dedicated to X-ray magnetic circular dichroism (XMCD) and material science under extreme conditions has been implemented in a bending-magnet port at the Brazilian Synchrotron Light Laboratory. Here the beamline technical characteristics are described, including the most important aspects of the mechanics, optical elements and detection set-up. The beamline performance is then illustrated through two case studies on strongly correlated transition metal oxides: an XMCD insight into the modifications of the magnetic properties of Cr-doped manganites and the structural deformation in nickel perovskites under high applied pressure. PMID:20029117

Cezar, Júlio C; Souza-Neto, Narcizo M; Piamonteze, Cínthia; Tamura, Edilson; Garcia, Flávio; Carvalho, Edson J; Neueschwander, Régis T; Ramos, Aline Y; Tolentino, Hélio C N; Caneiro, Alberto; Massa, Nestor E; Martinez-Lope, Maria Jesus; Alonso, Jose Antonio; Itié, Jean Paul

2009-11-17

94

Aliasing in a Hartmann wavefront sensor at x-ray wavelengths  

NASA Astrophysics Data System (ADS)

The Hartmann Sensor is a simple and well-established method to interrogate wavefront quality. Recently the Hartmann sensor has been used at very short wavelengths, including the extreme UV. Here we consider the Hartmann sensor and its ability to measure the wavefront of an x-ray beam. We use both analytic methods and a wave-optics, Fresnel-diffraction simulation. The Hartmann sensor samples the wavefront, which means that it is susceptible to aliasing (the non-linear phenomenon where high-spatial frequency components are incorrectly measured as low-spatial frequency components). Our analysis shows that aliasing is more severe in the Hartmann sensor than in the corresponding (optical) Shack-Hartmann. Aliasing worsens as Hartmann hole size shrinks. The wave-optics simulations show that for reasonable optics-polishing errors and Hartmann mask design, aliasing errors can be of the same magnitude as the phase that is to be measured.

Poyneer, Lisa A.; Bauman, Brian; Macintosh, Bruce

2012-10-01

95

A new X-ray pinhole camera for energy dispersive X-ray fluorescence imaging with high-energy and high-spatial resolution  

NASA Astrophysics Data System (ADS)

A new X-ray pinhole camera for the Energy Dispersive X-ray Fluorescence (ED-XRF) imaging of materials with high-energy and high-spatial resolution, was designed and developed. It consists of a back-illuminated and deep depleted CCD detector (composed of 1024 × 1024 pixels with a lateral size of 13 ?m) coupled to a 70 ?m laser-drilled pinhole-collimator, positioned between the sample under analysis and the CCD. The X-ray pinhole camera works in a coaxial geometry allowing a wide range of magnification values. The characteristic X-ray fluorescence is induced on the samples by irradiation with an external X-ray tube working at a maximum power of 100 W (50 kV and 2 mA operating conditions). The spectroscopic capabilities of the X-ray pinhole camera were accurately investigated. Energy response and energy calibration of the CCD detector were determined by irradiating pure target-materials emitting characteristic X-rays in the energy working-domain of the system (between 3 keV and 30 keV). Measurements were performed by using a multi-frame acquisition in single-photon counting. The characteristic X-ray spectra were obtained by an automated processing of the acquired images. The energy resolution measured at the Fe-K? line is 157 eV. The use of the X-ray pinhole camera for the 2D resolved elemental analysis was investigated by using reference-patterns of different materials and geometries. The possibility of the elemental mapping of samples up to an area of 3 × 3 cm2 was demonstrated. Finally, the spatial resolution of the pinhole camera was measured by analyzing the profile function of a sharp-edge. The spatial resolution determined at the magnification values of 3.2 × and 0.8 × (used as testing values) is about 90 ?m and 190 ?m respectively.

Romano, F. P.; Altana, C.; Cosentino, L.; Celona, L.; Gammino, S.; Mascali, D.; Pappalardo, L.; Rizzo, F.

2013-08-01

96

Second and third harmonic generation at UV and soft x-ray wavelengths from semiconductor gratings  

NASA Astrophysics Data System (ADS)

Extraordinary transmission properties are demonstrated in the UV range for GaAs gratings with sub-wavelength apertures under TM-polarization excitation. The metal-like response below 270nm, typical of several semiconductors such as GaAs or GaP, in fact may be used to excite surface waves that lead to enhance transmission in the linear regime and for novel nonlinear optical phenomena in the UV and soft X-ray ranges. An investigation of the linear transmission as a function of geometrical parameters of the grating reveals the formation of surface waves and relatively high transmission values even in regimes where the nominal absorption is significant. Strong field localization in subwavelength cavities and on the surface of the grating can be achieved under proper excitation conditions leading to the enhancement of harmonic generation. Nonlinear contributions to harmonic generation arise from symmetry breaking, the nonlinear magnetic Lorentz force, and from intrinsic, dipolar volume contributions. Preliminary results show promising nonlinear conversion efficiencies at wavelengths below 100nm, and demonstrate cross-coupling of TE and TM polarizations for pump and harmonic signals. A down-conversion process that can re-generate pump photons of polarization orthogonal compared to the incident pump field is also demonstrated.

Vincenti, M. A.; de Ceglia, D.; Scalora, M.

2011-09-01

97

LOCALIZING INTEGRAL SOURCES WITH CHANDRA: X-RAY AND MULTI-WAVELENGTH IDENTIFICATIONS AND ENERGY SPECTRA  

SciTech Connect

We report on Chandra observations of 18 hard X-ray (>20 keV) sources discovered with the INTEGRAL satellite near the Galactic plane. For 14 of the INTEGRAL sources, we have uncovered one or two potential Chandra counterparts per source. These provide soft X-ray (0.3-10 keV) spectra and subarcsecond localizations, which we use to identify counterparts at other wavelengths, providing information about the nature of each source. Despite the fact that all of the sources are within 5 Degree-Sign of the plane, four of the IGR sources are active galactic nuclei (AGNs; IGR J01545+6437, IGR J15391-5307, IGR J15415-5029, and IGR J21565+5948) and four others are likely AGNs (IGR J03103+5706, IGR J09189-4418, IGR J16413-4046, and IGR J16560-4958) based on each of them having a strong IR excess and/or extended optical or near-IR emission. We compare the X-ray and near-IR fluxes of this group of sources to those of AGNs selected by their 2-10 keV emission in previous studies and find that these IGR AGNs are in the range of typical values. There is evidence in favor of four of the sources being Galactic (IGR J12489-6243, IGR J15293-5609, IGR J16173-5023, and IGR J16206-5253), but only IGR J15293-5609 is confirmed as a Galactic source as it has a unique Chandra counterpart and a parallax measurement from previous optical observations that puts its distance at 1.56 {+-} 0.12 kpc. The 0.3-10 keV luminosity for this source is (1.4{sup +1.0}{sub -0.4}) Multiplication-Sign 10{sup 32} erg s{sup -1}, and its optical/IR spectral energy distribution is well described by a blackbody with a temperature of 4200-7000 K and a radius of 12.0-16.4 R{sub Sun }. These values suggest that IGR J15293-5609 is a symbiotic binary with an early K-type giant and a white dwarf accretor. We also obtained likely Chandra identifications for IGR J13402-6428 and IGR J15368-5102, but follow-up observations are required to constrain their source types.

Tomsick, John A.; Bodaghee, Arash [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Chaty, Sylvain; Rodriguez, Jerome [AIM (UMR-E 9005 CEA/DSM-CNRS-Universite Paris Diderot) Irfu/Service d'Astrophysique, Centre de Saclay, FR-91191 Gif-sur-Yvette Cedex (France); Rahoui, Farid [Astronomy Department, Harvard University, 60 Garden Street, Cambridge, MA 02138 (United States); Halpern, Jules [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027-6601 (United States); Kalemci, Emrah [Faculty of Engineering and Natural Sciences, Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I -Tuzla, Istanbul 34956 (Turkey); Oezbey Arabaci, Mehtap, E-mail: jtomsick@ssl.berkeley.edu [Physics Department, Middle East Technical University, Ankara 06531 (Turkey)

2012-08-01

98

X-ray photo-emission and energy dispersive spectroscopy of HA coated titanium  

SciTech Connect

The purpose of this study was to determine the chemical composition changes of hydroxyapatite (HA) coated titanium using surface analysis (x-ray photo-emission) and bulk analysis (energy dispersive spectroscopy). The specimens examined were controls, 30 minutes and 3 hours aged specimens in distilled water or 0.2M sodium phosphate buffer (pH 7.2) at room temperature. Each x-ray photo-emission cycle consisted of 3 scans followed by argon sputtering for 10 minutes for a total of usually 20 cycles, corresponding to a sampling depth of {approximately} 1500 {angstrom}. The energy dispersive spectroscopy analysis was on a 110 by 90 {mu}m area for 500 sec. Scanning electron microscopy examination showed crystal formation (3P{sub 2}O{sub 5}*2CAO*?H{sub 2}O by energy dispersive spectroscopy analysis) on the HA coating for the specimens aged in sodium phosphate buffer. The x-ray photo-emission results indicated the oxidation effect of water on the titanium (as TiO{sub 2}) and the effect of the buffer to increase the surface concentration of phosphorous. No differences in the chemical composition were observed by energy dispersive spectroscopy analysis. The crystal growth was only observed for the sodium phosphate buffer specimens and only on the HA surface.

Drummond, J.L.; Steinberg, A.D. [Univ. of Illinois, Chicago, IL (United States); Krauss, A.R. [Argonne National Lab., IL (United States)] [and others

1997-08-01

99

A Soft X-ray Spectrometer using a Highly Dispersive Multilayer Grating  

NASA Astrophysics Data System (ADS)

There is a need for higher resolution spectrometers as a tool for inelastic x-ray scattering. Currently, resolving power around R = 10,000 is advertised. Measured RIXS spectra are often limited by this instrumental resolution and higher resolution spectrometers using conventional gratings would be prohibitively large. We are engaged in a development program to build blazed multilayer grating structures for diffracting soft x-rays in high order. This leads to spectrometers with dispersion much higher than is possible using metal coated-gratings. The higher dispersion then provides higher resolution and the multilayer gratings are capable of operating away from grazing incidence as required. A spectrometer design is presented with a total length 3.8 m and capable of 105 resolving power.

Warwick, Tony; Padmore, Howard; Voronov, Dmitriy; Yashchuk, Valeriy

2010-06-01

100

Spatial high resolution energy dispersive X-ray spectroscopy on thin lamellas.  

PubMed

For conventional samples and measurement geometries the spatial resolution of energy dispersive X-ray spectroscopy is limited by a tear drop shaped emission volume to about 1 ?m. This restriction can be substantially improved using thin samples and high acceleration voltage. In this contribution the spatial resolution of energy dispersive X-ray spectroscopy in a scanning electron microscope using thin lamella samples is investigated. At an acceleration voltage of 30 kV, an edge resolution down to ?dedge = 40 ± 10 nm is observed performing linescans across an interface, using an 80 nm thin sample prepared from a GaAs/AlAs-heterostructure. Furthermore, Monte-Carlo simulations of pure elements ranging from sodium to mercury are performed for different sample thicknesses. From the simulations we can derive a simple empirical formula to predict the spatial resolution as a function of sample thickness. PMID:23545434

Notthoff, Christian; Winterer, Markus; Beckel, Andreas; Geller, Martin; Heindl, Jürgen

2013-02-18

101

A set-up for energy-dispersive X-ray diffraction measurements on weakly scattering (amorphous) materials  

Microsoft Academic Search

Describes the construction of a set-up for energy-dispersive X-ray diffraction measurements on weakly scattering (amorphous) samples. To minimise the effects of air scattering the diffraction chamber can be evacuated to pressures below 10 Pa. The set-up is fully radiation safe; the X-ray optics can be aligned by means of small DC-driven motors, while the X-ray beam is switched on. Some

W. Hoving; T. Egami; I. Vincze; F. van der Woude

1987-01-01

102

A characterization of Kapton polyimide by X-ray photoelectron spectroscopy and energy dispersive spectroscopy  

Microsoft Academic Search

Kapton polyimide films were characterized by X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS). The samples characterized include Kapton-H and Kapton-HN. The XPS data suggest that the Kapton films are mainly poly(4,4'-oxydiphenylene pyromellitimide). The Kapton-HN films were found to have imbedded particles which were identified by EDS to contain calcium and phosphorus. These films also give solid residues of

Pu Sen Wang; T. N. Wittberg; J. Douglas Wolf

1988-01-01

103

Analysis of stainless steel samples by energy dispersive X-ray fluorescence (EDXRF) spectrometry  

Microsoft Academic Search

A simple method for the analysis of stainless steel samples is presented which is based on radioisotope excited energy dispersive\\u000a X-ray fluorescence (EDXRF) spectrometry and does not require any type-standards. Both absorption and enhancement effects have\\u000a been taken into account in the fundamental parameter method for quantitative analysis and an iterative approach is followed\\u000a for calculation of concentrations in steel

M. K. Tiwari; A. K. Singh; K. J. S. Sawhney

2001-01-01

104

Multivariate Data Analysis for Drug Identification Using Energy-Dispersive X-Ray Diffraction  

Microsoft Academic Search

Preliminary studies have shown the effectiveness of multivariate analysis (MVA) for drug identification from energy-dispersive X-ray diffraction patterns. A statistical model to predict drug content from the diffraction profile of a sample of mixed composition was developed by applying MVA to both experimental and simulated data. Separate data-sets were used for building and testing the models. Both experimental and simulated

Emily J. Cook; Silvia Pani; Leah George; Sheila Hardwick; Julie A. Horrocks; Robert D. Speller

2009-01-01

105

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

Microsoft Academic Search

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

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

2003-01-01

106

Energy Dispersive X-Ray Absorption Spectroscopy: Beamline Results and Opportunities  

NASA Astrophysics Data System (ADS)

ID24 is the energy dispersive beamline of the European Synchrotron Radiation Facility dedicated to X-ray Absorption Spectroscopy (XAS). Since 2000, a complete refurbishment program has started, including source upgrade, mirrors replacement, polychromator optimization and detection improvements. These have made possible the development of new applications in a variety of different fields, ranging from the measurement of tiny atom displacements to time resolved techniques, from measurements under extreme conditions to micro-XAS studies.

Mathon, O.; Aquilanti, G.; Guilera, G.; Muñoz, M.; Newton, M. A.; Trapananti, A.; Pascarelli, S.

2007-01-01

107

Energy-dispersive X-ray analysis of the extracellular cadmium sulfide crystallites of Klebsiella aerogenes  

Microsoft Academic Search

Klebsiella aerogenes forms electron-dense partieles on the cell surface in response to the presence of cadmium ions in the growth medium. These particles ranged from 20 to 200 nm in size, and quantitative energy dispersive X-ray analysis established that they comprise cadmium and sulfur in a 1:1 ratio. This observation leads to the conclusion that the particles are cadmium sulfide

Justin D. Holmes; Peter R. Smith; Richard Evans-Gowing; David J. Richardson; David A. Russell; John R. Sodeau

1995-01-01

108

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

PubMed

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

Maalhagh-Fard, Ahmad; Wagner, Warren C

2004-09-01

109

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

Microsoft Academic Search

An energy dispersive X-ray fluorescence (EDXRF) tri-axial geometry experimental spectrometer has been employed to determine the concentrations of 13 different elements (K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr and Pb) in mine wastes from different depths of two mine tailings from the Cartagena-La Union (Spain) mining district. The elements were determined and quantified using the

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

2007-01-01

110

Study of local oxidative degradation in polypropylene impact copolymer by energy dispersive X-ray system  

Microsoft Academic Search

Summary In this study, the thermal oxidative degradation of a polypropylene (PP) impact copolymer was examined using a transmission electron microscope equipped with an energy dispersive X-ray system (TEM\\/EDX). The oxidative behavior was visually captured by oxygen line analysis. The oxidation resistance of the ethylene-propylene rubber (EPR) phase was considerably higher than that of the PP matrix, indicating that the

Norio Manabe; Yoshimitsu Yokota; Hisayuki Nakatani; Shoutarou Suzuki; Liu Boping; Minoru Terano

2005-01-01

111

At-wavelength and optical metrology of bendable x-ray optics for nanofocusing at the ALS  

SciTech Connect

We report on a new research and development program at the Advanced Light Source, Lawrence Berkeley National Lab directed to establish both at-wavelength and conventional optical metrology techniques suitable to characterize the surface profile of super-high-quality x-ray optics with sub-microradian precision.

Yashchuk, Valeriy V.

2009-06-11

112

The Absorption of X-Rays of Wave-Length down to.08A  

Microsoft Academic Search

Mass absorption coffiecients of C, paraffine, S and 16 metal elements from Al to U for wave-lengths.56 to.08A have been measured in continuation of previous work1 which covered most of these elements in the range.71 to.10A. The general radiation from a tungsten target (operated at voltages up to 200 kv) was dispersed by a crystal into an ionization chamber. By

S. J. Allen

1926-01-01

113

Energy dispersive X-ray analyses of organelles of NaCI-treated maize root cells  

NASA Astrophysics Data System (ADS)

NaCl sensitive plants of Zea mays cv. ADOUR were grown in nutrient solutions with or without NaCl. Frozen, hydrated root-tip tissues were investigated by means of an ETEC scanning electron microscope fitted with a KEVEX energy dispersive X-ray analyser. Morphological details of the gently etched but non-coated surface of the cross fractured specimen were easy to identify and to analyse using an electron beam with a low intensity at 10 kV. X-ray data obtained from cell compartments and organelles as nuclei, nucleoli and mitochondria within individual cells establish typical X-ray spectra. Comparisons of these spectra support the hypothesis that Na+ ions are predominantly localized in vacuoles and also to a lesser extent in the cytoplasm, e.g. in small vesicles, but not in other cell organelles. Furthermore the analysed cell compartments show differences in the distribution of Mg, P, S, Cl, K and Ca effected by the addition of NaCl to the growth medium. The X-ray data are discussed in relation to the physiological meaning of a NaCl induced redistribution of elements within individual maize root cells.

Stelzer, Ralf

1984-04-01

114

Grating-based at-wavelength metrology of hard x-ray reflective optics.  

PubMed

A mean of characterizing the tangential shape of a hard x-ray mirror is presented. Derived from a group of methods operating under visible light, its application in the x-ray domain using an x-ray absorption grating allows recovery of the mirror shape with nanometer accuracy and submillimeter spatial resolution. The method works with incoherent light, does not require any a priori information about the mirror characteristics and allows shape reconstruction of x-ray reflective optics under thermal and mechanical working conditions. PMID:23114330

Berujon, Sebastien; Ziegler, Eric

2012-11-01

115

Celebrating 40 years of energy dispersive X-ray spectrometry in electron probe microanalysis: a historic and nostalgic look back into the beginnings.  

PubMed

On February 2, 1968, R. Fitzgerald, K. Keil, and K.F.J. Heinrich published a seminal paper in Science (159, 528-530) in which they described a solid-state Si(Li) energy dispersive spectrometer (EDS) for electron probe microanalysis (EPMA) with, initially, a resolution of 600 eV. This resolution was much improved over previous attempts to use either gas-filled proportional counters or solid-state devices for EDS to detect X-rays and was sufficient, for the first time, to make EDS a practically useful technique. It ushered in a new era not only in EPMA, but also in scanning electron microscopy, analytical transmission electron microscopy, X-ray fluorescence analysis, and X-ray diffraction. EDS offers many advantages over wavelength-dispersive crystal spectrometers, e.g., it has no moving parts, covers the entire X-ray energy range of interest to EPMA, there is no defocusing over relatively large distances across the sample, and, of particular interest to those who analyze complex minerals consisting of many elements, all X-ray lines are detected quickly and simultaneously. PMID:19804655

Keil, Klaus; Fitzgerald, Ray; Heinrich, Kurt F J

2009-10-06

116

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

SciTech Connect

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

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

2011-11-28

117

Studies of short-wavelength collective molecular motions in lipid bilayers using high resolution inelastic X-ray scattering  

Microsoft Academic Search

We summarize a series of experimental results made with the newly developed high resolution X-ray scattering (IXS) instrument on two pure lipid bilayers, including dimyristoylphosphatidylcholine (DMPC) and dilauroylphosphatidylcholine (DLPC) in both gel and liquid crystal phases, and lipid bilayers containing cholesterol. By analyzing the IXS data based on the generalized three effective eigenmode model (GTEE), we obtain dispersion relations of

Poe-Jou Chen; Yun Liu; Thomas M. Weiss; Huey W. Huang; Harald Sinn; Ercan E. Alp; Ahmet Alatas; Ayman Said; Sow-Hsin Chen

2003-01-01

118

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

NASA Astrophysics Data System (ADS)

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

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

1997-07-01

119

Multi-wavelength diagnostics of accretion in an X-ray selected sample of CTTSs  

NASA Astrophysics Data System (ADS)

The majority of CTTSs observed to date with high spectral resolution X-ray spectroscopy reveal soft X-ray emission (E<0.7 KeV) which originates from cool (1-5 MK), high density (n ˜ 10^{11}-10^{13} cm^{-3}) plasma. This is currently interpreted to be due to mass accretion. Supporting this interpretation is the fact that this plasma component is too dense to have a coronal origin, and it has never been observed in non-accreting stars. Synthesized X-ray spectra from detailed hydrodynamical modelling of the interaction between the accretion flow and the stellar chromosphere also confirm this interpretation. However, the mass accretion rates derived from X-ray data are consistently underestimated when compared to mass accretion rates derived from UV/optical data. We test the hypothesis that this soft X-ray emission originates from accretion by analysing optical, NIR and X-ray data for an X-ray selected sample of CTTSs. We derive mass accretion rates for the sample based on H?, He I, O I and Ca II emission lines, along with the X-ray data. We draw comparisons between these mass accretion rates to understand the underestimation of the X-ray derived mass accretion rates. We discuss the possibilities of a) the X-ray emission being partially absorbed, b) the optical/NIR emission arising from different parts of the accretion stream and c) the uncertainties involved in the estimation of the mass accretion rates from different spectroscopic diagnostics.

Curran, Rachel; Argiroffi, Costanza; Sacco, Giuseppe Germano; Orlando, Salvatore; Reale, Fabio; Peres, Giovanni; Maggio, Antonio

2009-09-01

120

New software to model energy dispersive X-ray diffraction in polycrystalline materials  

NASA Astrophysics Data System (ADS)

Detection of illicit materials, such as explosives or drugs, within mixed samples is a major issue, both for general security and as part of forensic analyses. In this paper, we describe a new code simulating energy dispersive X-ray diffraction patterns in polycrystalline materials. This program, SinFullscat, models diffraction of any object in any diffractometer system taking all physical phenomena, including amorphous background, into account. Many system parameters can be tuned: geometry, collimators (slit and cylindrical), sample properties, X-ray source and detector energy resolution. Good agreement between simulations and experimental data was obtained. Simulations using explosive materials indicated that parameters such as the diffraction angle or the energy resolution of the detector have a significant impact on the diffraction signature of the material inspected. This software will be a convenient tool to test many diffractometer configurations, providing information on the one that best restores the spectral diffraction signature of the materials of interest.

Ghammraoui, B.; Tabary, J.; Pouget, S.; Paulus, C.; Moulin, V.; Verger, L.; Duvauchelle, Ph.

2012-02-01

121

X-ray fluorescence and energy dispersive x-ray diffraction for the quantification of elemental concentrations in breast tissue  

Microsoft Academic Search

This paper presents improvements on a previously reported method for the measurement of elements in breast tissue specimens (Geraki et al 2002 Phys. Med. Biol. 47 2327-39). A synchrotron-based system was used for the detection of the x-ray fluorescence (XRF) emitted from iron, copper, zinc and potassium in breast tissue specimens, healthy and cancerous. Calibration models resulting from the irradiation

K. Geraki; M. J. Farquharson; D. A. Bradley

2004-01-01

122

X-ray fluorescence and energy dispersive x-ray diffraction for the quantification of elemental concentrations in breast tissue  

Microsoft Academic Search

This paper presents improvements on a previously reported method for the measurement of elements in breast tissue specimens (Geraki et al 2002 Phys. Med. Biol.47 2327–39). A synchrotron-based system was used for the detection of the x-ray fluorescence (XRF) emitted from iron, copper, zinc and potassium in breast tissue specimens, healthy and cancerous. Calibration models resulting from the irradiation of

K Geraki; M J Farquharson; D A Bradley

2004-01-01

123

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

PubMed

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

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

2011-09-09

124

Automation of dihydroxyaluminum sodium carbonate analysis in antacid tablets by energy dispersive X-ray fluorescence.  

PubMed

A sensitive, specific, automated energy dispersive X-ray fluorescence (EDXRF) method for determination of anhydrous dihydroxyaluminum sodium carbonate in antacid tablets has been developed. The compound was quantitated by impact grinding, pelletizing at 10 tons pressure, and monitoring the aluminum by using a rhodium anode X-ray tube, high resolution thermoelectrically cooled Si(Li) detector with sample spinning, and computer data processing. The assay procedure was validated with spiked laboratory-prepared samples at 100 +/- 20% levels. The average recovery was 100.6% with a relative standard deviation of 1.6% (n = 14). Instrument precision was determined and found to have an average relative standard deviation of 1.0% (n = 16). In addition, analysis precision by the EDXRF method was compared to that for titration and autoanalyzer methodologies and found to be statistically comparable. The sample precision had an averaged relative standard deviation of 2.7% (n = 16) by X-ray methodology. The advantages of this EDXRF method include increased sample throughout with excellent precision and accuracy, no solvent usage, and automated data handling. PMID:2376540

Georgiades, C A

125

A Determination of he from the Short Wave-Length Limit of the Continuous X-Ray Spectrum  

Microsoft Academic Search

Two precision determinations of the short wave-length limits of the continuous x-ray spectrum have been made, one in the region of 10,000 volts, the other in the region of 20,000 volts by the method of isochromats under very steady applied voltage. The two crystal spectrometer was used as a monochromator. The Kbeta2 line of molybdenum and the Lbeta1 line of

Jesse Dumond; Vernon Bollman

1937-01-01

126

Characterization of the Carancas-Puno meteorite by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Mössbauer spectroscopy  

NASA Astrophysics Data System (ADS)

We report the results of the study of a meteorite that impacted an inhabited zone on 15 September 2007 in the neighborhood of the town of Carancas, Puno Region, about 1,300 km south of Lima. The analysis carried out by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Mössbauer spectroscopy (at room temperature and at 4.2 K), reveal the presence in the meteorite sample of magnetic sites assigned to taenite (Fe,Ni) and troilite (Fe,S) phases, and of two paramagnetic doublets assigned to Fe2 + , one associated with olivine and the other to pyroxene. In accord with these results, this meteorite is classified as a type IV chondrite meteorite.

Cerón Loayza, María L.; Bravo Cabrejos, Jorge A.

2011-08-01

127

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

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

128

Characterization of the Carancas-Puno meteorite by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Mössbauer spectroscopy  

NASA Astrophysics Data System (ADS)

We report the results of the study of a meteorite that impacted an inhabited zone on 15 September 2007 in the neighborhood of the town of Carancas, Puno Region, about 1,300 km south of Lima. The analysis carried out by energy dispersive X-ray fluorescence, X-ray diffractometry and transmission Mössbauer spectroscopy (at room temperature and at 4.2 K), reveal the presence in the meteorite sample of magnetic sites assigned to taenite (Fe,Ni) and troilite (Fe,S) phases, and of two paramagnetic doublets assigned to Fe2 + , one associated with olivine and the other to pyroxene. In accord with these results, this meteorite is classified as a type IV chondrite meteorite.

Cerón Loayza, María L.; Bravo Cabrejos, Jorge A.

2011-11-01

129

Nanoscale Imaging with Resonant Coherent X Rays: Extension of Multiple-Wavelength Anomalous Diffraction to Nonperiodic Structures  

SciTech Connect

The methodology of multiple-wavelength anomalous diffraction, widely used for macromolecular structure determination, is extended to the imaging of nonperiodic nanostructures. We demonstrate the solution of the phase problem by a combination of two resonantly recorded coherent scattering patterns at the carbon K edge (285 eV). Our approach merges iterative phase retrieval and x-ray holography approaches, yielding unique and rapid reconstructions. The element, chemical, and magnetic state specificity of our method further renders it widely applicable to a broad range of nanostructures, providing a spatial resolution that is limited, in principle, by wavelength only.

Scherz, A.

2010-03-02

130

X-ray spectrometry using polycapillary X-ray optics and position sensitive detector.  

PubMed

Polycapillary X-ray optics (capillary X-ray lens) are now popular in X-ray fluorescence (XRF) analysis. Such an X-ray lens can collect X-rays emitted from an X-ray source in a large solid angle and form a very intense X-ray microbeam which is very convenient for microbeam X-ray fluorescence (MXRF) analysis giving low minimum detection limits (MDLs) in energy dispersive X-ray fluorescence (EDXRF). A new method called position sensitive X-ray spectrometry (PSXS) which combines an X-ray lens used to form an intense XRF source and a position sensitive detector (PSD) used for wavelength dispersive spectrometry (WDS) measurement was developed recently in the X-ray Optics Laboratory of Institute of Low Energy Nuclear Physics (ILENP) at Beijing Normal University. Such a method can give high energy and spacial resolution and high detection efficiency simultaneously. A short view of development of both the EDXRF using a capillary X-ray lens and the new PSXS is given in this paper. PMID:18968083

Ding, X; Xie, J; He, Y; Pan, Q; Yan, Y

2000-10-01

131

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

SciTech Connect

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

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

1990-03-01

132

[Boundary threshold value method used in crystalline material internal defect detection by short wavelength X-ray diffraction].  

PubMed

There are few references about crystalline material internal defect detected by X-ray diffraction tomography using common X-ray source. Short wavelength X-ray diffractometer (SWXRD), invented by Institute of Southwest Technology Engineering, is a relatively small and inexpensive instrument compared to synchrotron radiation or neutron reactor. Boundary determination of defect affects the imaging quality and the distinguishing of defect in X-ray diffraction tomography using SWXRD. In the present paper, threshold value method of diffracted intensity is put forward to process the test data, so the boundary of defect is legible. In order to study how the factors influence the threshold value, Gauss function is used in fitting the test data. The influence of varisized image quality indicator pressed in powdered aluminum on threshold value has been studied. The result shows that 91% of the diffraction intensity of substrate can be regarded as the threshold value. The experiment of slit in aluminum alloy sheet further verified the threshold value method. It's useful in detecting the defect boundary. PMID:21847964

Mu, Jian-Lei; Zhang, Jin; Gao, Zheng-Huan; Zheng, Lin; He, Chang-Guang

2011-06-01

133

The manufacture of a very high precision x-ray collimator array for rapid tomographic energy dispersive diffraction imaging (TEDDI)  

Microsoft Academic Search

A very high resolution x-ray collimator array has been constructed for use with tomographic energy dispersive diffraction imaging (TEDDI). The collimator consists of a 16 × 16 array of 50 µm diameter holes in a series of 0.1 mm tungsten plates aligned to a tolerance of ±2 µm. The minimum angular divergence of the transmitted x-ray beams through each transmission

L. Tunna; P. Barclay; R. J. Cernik; K. H. Khor; W. O'Neill; P. Seller

2006-01-01

134

Annulus-sector-element coded Gabor zone plate at the x-ray wavelength.  

PubMed

It is proposed in this paper that an x-ray Gabor zone plate can be realized by properly arranging annulus-sector-shaped nanometer structure apertures along each zone. This provides a new coding methodology which can be used to fabricate a binary zone plate with single order foci only. Numerical simulation results show good agreement with the physical design. PMID:22108991

Wei, Lai; Kuang, Longyu; Fan, Wei; Zang, Huaping; Cao, Leifeng; Gu, Yuqiu; Wang, Xiaofang

2011-10-24

135

Strain field and scattered intensity profiling with energy dispersive x-ray scattering  

NASA Astrophysics Data System (ADS)

Two powerful synchrotron x-ray scattering techniques for residual strain depth-profiling and tomography-like scatter-intensity profiling of materials are presented. The techniques utilize energy dispersive x-ray scattering, from a fixed microvolume, with microscanning of the specimen being used to profile its interior. The tomography-like profiles exploit scattering-cross-section variations, and can be contrast enhanced by separately monitoring scattering from different crystal structures. The strain profiling technique is shown to finely chronicle the internal strain variation over several mm of steel. Detailed strain profiling for a cantilever spring demonstrates the interplay of residual and external stresses in elastic/plastic deformation. Since surface compression, by shot peening, is a classic method to fortify against fatigue failure, the strain profile for a shot-peened, surface-toughened material is determined and discussed in terms of a simple elastic-plastic stress/strain model. Finally the lattice strains in a WC/Co coated steel composite material are discussed.

Croft, M.; Zakharchenko, I.; Zhong, Z.; Gurlak, Y.; Hastings, J.; Hu, J.; Holtz, R.; Dasilva, M.; Tsakalakos, T.

2002-07-01

136

Development of a prototype pipework scanning system based upon energy dispersive X-ray diffraction (EDXRD)  

NASA Astrophysics Data System (ADS)

A prototype pipework scanning system based upon energy dispersive X-ray diffraction (EDXRD) has been produced, for which system development and preliminary results are presented here. This apparatus has been developed from experience with 2D and 3D bench-top EDXRD systems and comprises a conventional industrial X-ray tube coupled to a bespoke design of tungsten collimators and compact CdTe detector. It is designed as a robust system, rather than delicate lab-based system, to investigate sections of stainless steel pipework for structural changes induced through quenching the steel in liquid nitrogen, and damaging effects such as chloride-induced stress corrosion cracking (SCC). Given the properties of tungsten, namely its brittle nature, a complex programme of electro-discharge machining (EDM) has been devised to precisely manufacture the collimators from a series of sintered tungsten blocks. Preliminary measurements have focused on calibrating the system using the extreme ferrite and austenite phases, meeting a pre-requisite benchmark for attempting more challenging measurements such as the austenite to martensite transformation and investigations of SCC in these sections of pipework.

Garrity, D. J.; de Rosa, A. J.; Bradley, D. A.; Jarman, S. E.; Jenneson, P. M.; Vincent, S. M.

2010-07-01

137

Tunable dispersion compensator with integrated wavelength locking  

Microsoft Academic Search

We demonstrate a compact and simple silica-waveguide 10-Gb\\/s dispersion compensator that works with uncontrolled wavelength transmitters by tracking the signal wavelength. 10.7-Gb\\/s transmissions over 5100ps\\/nm with duobinary and 3825ps\\/nm with unchirped NRZ are shown.

C. R. Doerr; S. Chandrasekhar; L. L. Buhl; M. A. Cappuzzo; E. Y. Chen; A. Wong-Foy; L. T. Gomez

2005-01-01

138

Efficient soft x-ray lasing at wavelengths of 20 to 30 nm  

Microsoft Academic Search

Intense lasing at 18.9, 20.3 and 28.5 nm from nickel-like molybdenum, niobium and neon-like chromium ions has been observed by using two 200 ps laser pulses with a total energy of 50 J at 1.053 micrometers from XingGuang II laser facility. This shows the possibility of extending nickel- like and neon-like x-ray lasing in low-Z elements and paves the way

Jie Zhang; Y. Q. Gu; Y. J. Li; Y. T. Li; S. T. Chunyu; Y. L. You; WenZhong Huang; S. T. He; Y. L. He; L. Z. Lu; X. D. Yuan; XiaoFeng Wei; Chuanfei Zhang

1999-01-01

139

Constraining accretion from coordinated multi-wavelength rapid timing observations of X-ray binaries  

NASA Astrophysics Data System (ADS)

It has long been believed that the optical and infrared (OIR) fluxes of compact accreting sources will not generally show fast, stochastic variability. This is because reprocessing of high energy photons is thought to be the primer driver of the OIR fluxes. In recent work, we have found fast (sub-second) optical variations in accreting black hole and neutron star binaries. The power spectra of the source light curves show wide-band noise and even low-frequency quasi-periodic oscillations. These are characteristics very similar to those found in X-ray observations. The OIR fluxes show some clear and intriguing correlations with the X-ray fluxes on timescales of 0.1-10 s, which can place quantitative physical constraints on the accretion processes for the first time. Detailed statistical analyses including the inter-band coherence, phase lags and rms spectrum will be discussed. These show unambiguously that at least two separate components (e.g. a jet and a corona) are interacting via some underlying connections (e.g. a strong magnetic field threading the entire inner flow regions). OIR timing studies are thus proving detailed insight on compact accreting sources, complementing X-ray constraints.

Gandhi, P.; Makishima, K.; Dhillon, V. S.; Marsh, T. R.; Fabian, A. C.; Malzac, J.; Kubota, A.

2010-12-01

140

Soil characterization by energy dispersive X-ray fluorescence: sampling strategy for in situ analysis.  

PubMed

This work describes a sampling strategy that will allow the use of portable EDXRF (energy dispersive X-ray fluorescence) instruments for "in situ" soil analysis. The methodology covers a general approach to planning field investigations for any type of environmental studies and it was applied for a soil characterization study in the zone of Campana, Argentina, by evaluating data coming from an EDXRF spectrometer with a radioisotope excitation source. Simulating non-treated sampled as "in situ" samples and a soil characterization for Campana area was intended. "In situ" EDXRF methodology is a powerful analytical modality with the advantage of providing data immediately, allowing a fast general screening of the soil composition. PMID:16038489

Custo, Graciela; Boeykens, Susana; Dawidowski, L; Fox, L; Gómez, D; Luna, F; Vázquez, Cristina

2005-07-01

141

Quantitative energy dispersive X-ray analysis of submicrometric particles using a scanning electron microscope.  

PubMed

The quantitative scanning electron microscope-energy dispersive X-ray (SEM-EDX) analysis of a horneblende and two augite prismatic samples reduced to submicrometric particles was performed, and error due to the particle effects ("absent mass" and the "reduced absorption" effect) was minimized. Correction factors as a function of fragment size were obtained for O, Na, Mg, Si, Ca, and Fe. In addition, the influence of chemical composition of the samples used as standards (the matrix effect) on correction factors was evaluated. The results indicate that the absent mass effect is dominant for all elements except for the light elements O and Na, for which the reduced absorption effect is dominant. No significant matrix effect has been observed. By using corrected SEM-EDX data, the error on quantification of the element concentration has been estimated to be 3% relative for light elements and below 2% relative for heavy elements (notably, about 1% relative for Fe). PMID:21892993

Paoletti, Luigi; Bruni, Biagio M; Gianfagna, Antonio; Mazziotti-Tagliani, Simona; Pacella, Alessandro

2011-09-06

142

Neighborite Under High Pressure: In Situ Angle Dispersive X-ray Diffraction Study Using Synchrotron Radiation  

NASA Astrophysics Data System (ADS)

The neighborite (NaMgF3) is an ideal analogue model for silicate perovskite (MgSiO3) due to the similarities between their crystal and electronic structures. The advantage of the analogue study is that the weaker bonding feature of neighborite grants us the opportunity to simulate behavior of silicate perovskite at lower mantlei. e.high pressure and high temperature condition, at relatively lower P-T conditions. The previous high pressure studies for neighborite were reported by Zhao et al [1, 2]. Energy dispersive x-ray diffraction data were achieved within 10GPa and 1000oC, while angle dispersive x-ray diffraction data were obtained only at 4.9GPa and room temperature.More information of atomic position change is required to reveal the role of MgF6 octahedral framework tilting during its phase transition process responding to heating andcompressing. Thus the high-resolution monochromatic x-ray powder diffraction studies on NaMgF3 perovskite at high pressure were carried out using diamond anvil cell at X17C of National Synchrotron Light Source (Brookhaven) and HPCAT of Advance Photon Source (Argonne). The orthorhombic structure keeps stable under pressure up to 30 GPa, and the crystal structure is refined using Rietveld method. The result indicates that tilting angle of the MgF6 octahedral framework increases continually while the octahedral Mg-F bond length decreases slightly with increasing pressure.Difference between the tilting angles derived from macro-structure (lattice parameters) and from micro-structure (atomic positions), as well as the trend of change in the tilting angle with temperature and pressureare discussed. [1]. Zhao YS, Weidner DJ, Ko JD, Leinenweber K, Liu X, Li BS, Meng Y,Pacalo REG, Vaughan MT, Wang YB, Yeganehhaeri A,J.Geophys. Res. Solid Earth, 99 (1994) 2871. [2]. Zhao YS, Parise JB, Wang YB, Kusaba K, Vaughan MT, Weidner DJ, Kikegawa T, Chen J, Shimomura O,Am.Miner., 79 (1994) 615.

Liu, H.; Chen, J.; Weidner, D.; Hu, J.; Meng, Y.; Mao, H.

2003-12-01

143

Hot Electron and X-ray Production from Intense Laser Irradiation of Wavelength-scale Polystyrene Spheres  

NASA Astrophysics Data System (ADS)

In an attempt to control the electric fields at the surface of a high intensity solid target we have studied hot electron generation and x-ray production from targets coated with microspheres. This work is motivated by the possibility that spheres with size comparable to the wavelength of the incident laser radiation can result in electric field enhancements through well know Mie resonances. This local field enhancement can then lead to more efficient electron generation. We investigated hard x-ray (above 100 keV) generation from copper and fused silica targets coated with a monolayer covering of polystyrene microspheres. We performed the experiment using the 20 TW THOR laser system at the University of Texas. We frequency doubled the laser to improve temporal contrast and irradiated the spheres with 400 nm pulses at an intensity of 2 x 1017 W/cm2. Hard X-ray emission from the plasma was observed using filtered NaI scintillation detectors and K-alpha emission was measured with a Von Hamos spectrometer. We illuminated polystyrene spheres of diameters 0.1 -2.9 microns on a glass substrate, with the 400 nm 100fs pulse, and find that there is a clear Mie enhancement in the field and hot electron generation for a specific range of sphere sizes.

Ditmire, T.; Sumeruk, H. A.; Kneip, S.; Symes, D. R.; Churina, I. V.; Belolipetski, A. V.; Dyer, G.; Bernstein, A.; Donnelly, T. D.

2008-04-01

144

APEX/J-PEX: A High-Resolution Spectrometer for EUV/X-ray Wavelengths  

NASA Astrophysics Data System (ADS)

Future X-ray and EUV missions should include high-resolution spectrometers, permitting use of the full range of spectroscopic diagnostics, in particular measurement of line profiles and Doppler shifts. We present a design for such an instrument (APEX), which would fly on a Small Explorer Satellite and which employs multilayer-coated ion-etched gratings in a normal-incidence configuration. We have already flown successfully a prototype spectrometer (J-PEX) on a NASA sounding rocket. The resulting EUV spectrum of the white dwarf G191-B2B will be presented.

Kowalski, M. P.; Cruddace, R. G.; Gursky, H.; Yentis, D. J.

2001-09-01

145

Phase development in the hardening process of two calcium phosphate bone cements: an energy dispersive X-ray diffraction study  

SciTech Connect

This work was aimed at the application of an energy dispersive X-ray diffraction technique to study the kinetics of phase development during the setting and hardening reactions in two calcium phosphate bone cements. The cements under study are based on either tricalcium phosphate or tetracalcium phosphate initial solid phase, and a magnesium carbonate-phosphoric acid liquid phase as the hardening liquid. The application of the energy dispersive X-ray diffraction method allowed to collect the diffraction patterns from the cement pastes in situ starting from 1 min of the setting and hardening process. The only crystallized phase in both cements was apatite-like phase, the primary crystallization process proceeds during a few seconds of the setting reaction. Both the compressive strength and the pH value changes during the hardening period can be attributed to the transformations occurring in the intergranular X-ray amorphous phase.

Generosi, A. [Istituto di Struttura della Materia, CNR, via del Fosso del Cavaliere, 100-00133 Rome (Italy); Smirnov, V.V. [Institute for Physical Chemistry of Ceramics, Russian Academy of Sciences, Ozernaya 48, Moscow 119361 (Russian Federation); Rau, J.V. [Istituto per lo Studio dei Materiali Nanostrutturati, CNR, Piazzale Aldo Moro, 5-00185 Rome (Italy); Albertini, V. Rossi [Istituto di Struttura della Materia, CNR, via del Fosso del Cavaliere, 100-00133 Rome (Italy); Ferro, D. [Istituto per lo Studio dei Materiali Nanostrutturati, CNR, Piazzale Aldo Moro, 5-00185 Rome (Italy); Barinov, S.M. [Institute for Physical Chemistry of Ceramics, Russian Academy of Sciences, Ozernaya 48, Moscow 119361 (Russian Federation)], E-mail: barinov_s@mail.ru

2008-03-04

146

Metastable phase diagram of Bi probed by single-energy x-ray absorption detection and angular dispersive x-ray diffraction  

NASA Astrophysics Data System (ADS)

In this paper we report the results of a detailed experimental study of samples composed of micrometric Bi droplets providing an insight into the metastable phase diagram of Bi. To this purpose we have used the single-energy x-ray absorption detection technique in combination with angular dispersive x-ray diffraction available at the BM29 beamline of the European Synchrotron Radiation Facility. This unconventional approach has given proof of being a different and reliable tool for detecting subtle structural modifications in condensed matter. The investigation has revealed a large variety of metastable Bi polymorphs in a broad range of pressures and temperatures ( 25-500°C , 0-6GPa ) and the occurrence of a Bi crystalline structure isomorphic to the ? -tin structure. We have shown that the range of undercooling of liquid Bi strongly depends upon pressure and the underlying solid stable and metastable phases. As a final result a Bi-phase diagram including metastable phases is proposed, which takes into account all structural information obtained from this experiment.

Principi, E.; Minicucci, M.; di Cicco, A.; Trapananti, A.; de Panfilis, S.; Poloni, R.

2006-08-01

147

Energy-dispersive X-ray diffraction studies of the texture in cold-rolled alpha-beta brass  

Microsoft Academic Search

It is shown that energy-dispersive X-ray diffraction can be used for simultaneous measurement of several pole figures and that the accuracy is sufficient for the determination of the crystallite orientation distribution. The method is applied to the study of the texture in Cu-43 wt % Zn duplex alpha-beta brass rolled to 80% reduction.

J. Szpunar; L. Gerward

1980-01-01

148

Identification of Heroin Covered by Simulation Skin Using Energy Dispersive X-ray Diffraction and Coherence Function  

Microsoft Academic Search

An inspection technique based on energy dispersive X-ray diffraction (EDXRD) has been developed to provide chemically specific detection of samples. Implementing this technique and coupling with appropriate analysis algorithm provide specific material identification. Profile analysis has been performed using the Coherence Function. The Results suggest that it is feasible to recognize heroin covered by simulation skin through coherence function analysis

Fang Zhang; Minqiang Li; Chang-Xing Qi; Sun Bai; Yu Zhong; Daoyang Yu; Jin-huai Liu

2010-01-01

149

Application of Singular Value Decomposition for Identification of Liquid Precursor Chemicals Using Energy-Dispersive X-Ray Scattering  

Microsoft Academic Search

A new method based on singular value decomposition (SVD) was developed to identify liquid precursor chemicals in this paper. Feature scattering spectra of several kinds of pure liquid precursor chemicals were described through energy-dispersive x-ray scattering (EDXRS). These spectra, each of which was unique to particular liquid, were organized as matrices for SVD after truncation and smoothing. It was demonstrated

Yu Zhang; Min-Qiang Li; Yu Zhong; Wei Li; Bai Sun; Dao-Yang Yu; Jin-Huai Liu

2011-01-01

150

Energy dispersive X-ray microanalysis of neurosecretory granules of mouse pituitary on fresh air-dried tissue spreads  

Microsoft Academic Search

Electron microscopy of fresh air dried spreads of unstained posterior lobe tissue from mouse pituitary disclosed neurosecretory granules. Each granule showed a seemingly homogeneous dense core surrounded by a halo and a bounding membrane. The area between granules in the cytoplasm was relatively well preserved. The energy dispersive X-ray microanalysis revealed peaks for sulfur, chlorine and potassium in two granules.

Kenichi Takaya

1975-01-01

151

A general Monte Carlo simulation of energy-dispersive X-ray fluorescence spectrometers — Part 6. Quantification through iterative simulations  

NASA Astrophysics Data System (ADS)

A quantification tool for energy-dispersive X-ray fluorescence (ED-XRF) spectral data is presented, based on the application of Monte Carlo simulations in an iterative, inverse manner. Acting as an open-source plug-in to the widespread PyMca package, it provides users with a superior alternative to the fundamental parameter method based built-in quantification tool, taking into account higher order interactions, M-lines and cascade effects. Examples are shown demonstrating the usefulness of our implementation through data recorded at the synchrotron X-ray fluorescence microprobe installed at the HASYLAB Beamline L, Hamburg, Germany.

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

2013-04-01

152

? and ?-band dispersion of graphite from polarized resonant inelastic X-ray scattering measurements  

Microsoft Academic Search

Resonant inelastic X-ray scattering of highly oriented pyrolytic graphite (HOPG) is observed above the C 1s threshold at different polarization angles. It is shown that combining the polarization and excitation energy dependence\\u000a of X-ray emission spectra makes it possible to perform quantitative band mapping selective to the chemical bonding (? and\\u000a ?).

A. V. Sokolov; E. Z. Kurmaev; J. MacNaughton; A. Moewes; N. A. Skorikov; L. D. Finkelstein

2003-01-01

153

ENERGY-DISPERSIVE, X-RAY REFLECTIVITY DENSITY MEASUREMENTS OF POROUS SIO2 XEROGELS  

EPA Science Inventory

X-ray reflectivity has been used to nondestructively measure the density of thin, porous, SiO2-based xerogels. Critical angle, defined by total external reflection, was measured for multiple x-ray energies to correct for sample misalignment error in me determination of the densit...

154

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

NASA Astrophysics Data System (ADS)

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

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

2007-05-01

155

Mercuric iodide detector systems for identifying substances by x-ray energy dispersive diffraction  

SciTech Connect

The use of mercuric iodide arrays for energy-dispersive x-ray diffraction (EDXRD) spectroscopy is now being investigated by the authors for inspection of specific crystalline powders in substances ranging from explosives to illicit drugs. Mercuric iodide has been identified as the leading candidate for replacing the Ge detectors previously employed in the development of this technique because HgI{sub 2} detectors: operate at or near room temperature; without the bulky apparatus associated with cryogenic cooling; and offer excellent spectroscopy performance with extremely high efficiency. Furthermore, they provide the practicality of constructing optimal array geometries necessary for these measurements. Proof of principle experiments have been performed using a single-HgI{sub 2} detector spectrometer. An energy resolution of 655 eV (FWHM) has been obtained for 60 keV gamma line from an {sup 241}Am source. The EDXRD signatures of various crystalline powdered compounds have been measured and the spectra obtained show the excellent potential of mercuric iodide for this application.

Iwanczyk, J.S.; Patt, B.E.; Wang, Y.J. [Xsirius, Inc., Camarillo, CA (United States); Croft, M.; Kalman, Z.; Mayo, W. [Rutgers-The State Univ., Piscataway, NJ (United States)

1995-08-01

156

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

NASA Astrophysics Data System (ADS)

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

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

2007-08-01

157

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

SciTech Connect

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

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

2012-12-21

158

Probable X-Ray Mass Absorption Coefficients for Wave-Lengths Shorter Than the K Critical Absorption Wave-Length  

Microsoft Academic Search

Absorption coefficients of all elements may be calculated, from short wave-lengths up to the K critical absorption wave-length by the expression: ??&rgr;=??3Z2(2Z?A)???4Z5(2Z?A)+?eN0(Z?A). This formula holds for all elements when suitable values for ? and ? are chosen. Factors ? and ? are related to the atomic number, Z, by the expressions ?=(aZ2+bZ?c), and ?=(dZ2?eZ+f). Different values of the constants a,

John A. Victoreen

1943-01-01

159

Analysis of aerosols using total reflection X-ray spectrometry and industrial process monitoring using EDXRF (Energy Dispersive X-ray Fluorescence)  

SciTech Connect

Total reflection X-ray fluorescence (TXRF) was used to determine sulfur, chlorine, potassium, and calcium in atmospheric aerosol samples. Aerosols collected in a size fractionation cascade impact collector were dissolved in water, and the solution was placed on a quartz X-ray reflector plate. Cobalt was used as the internal standard added to the solution after dissolution of the aerosol. Detection units as low as 325 pg for sulfur and between 38 and 387 {mu}g were used to prepare the specimens. Good agreement was obtained between sulfur calculated as sulfate obtained by TXRF and sulfate obtained by ion chromatographic determination. Energy dispersive XRF was evaluated for on-line analysis of liquid and powdered materials. A prototype EDXRF instrument was developed and evaluated for on-line analysis of liquids. The flow cell used in the prototype instruments incorporates a thin polyvinyl fluoride film in a Teflon body to provide a window for the detection of fluorescent radiation from the sample. Lead and bromine were determined in leaded gasoline. Lower limits of detection were established for several other elements in a hydrocarbon matrix. Particle size effects were evaluated for on-line analysis of powdered materials. Monominerallic size fractions of galena, pyrite, and quartz were examined and an empirical correction method was proposed for reduction of particle size effects in homogeneous materials. The empirical correction method was applied to potash samples for size fractions up to 250 {mu}m. The potassium intensities in potash were corrected to a small uniform particle size within 2.6% RSD.

Leland, D.J.

1989-01-01

160

X-Rays  

NSDL National Science Digital Library

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

161

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

PubMed

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

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

2011-01-01

162

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

Microsoft Academic Search

Synchrotron radiation induced total reflection X-ray fluorescence and conventional 45° energy dispersive X-ray fluorescence analysis using a 150-nm-thick AP1™ film as sample carrier have been exploited for the elemental analysis of traces in alloys used for the construction of reactor core components of nuclear power plants. Both techniques are well suited for the analysis since they require a low amount

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

2001-01-01

163

Absolute calibration of X-ray optical elements and detectors at a wavelength of 46.9 nm  

Microsoft Academic Search

The results are presented of the absolute calibration of X-ray optical elements (diffraction gratings and Sc\\/Si multilayers)\\u000a and detectors (an ??-4 photographic film and a vacuum X-ray diode) used in diagnostic devices to study generation of X-ray\\u000a laser radiation in an argon plasma of a capillary discharge (? = 46.9 nm). The measurements have been performed at the soft\\u000a X-ray

O. N. Gilev; D. A. Vikhlyaev; A. A. Legkodymov; A. D. Nikolenko

2010-01-01

164

Double crystal dispersion monochromator for X-ray plane wave diffraction  

Microsoft Academic Search

A double crystal monochromator for X-ray plane-wave diffraction is proposed. It is possible to cut the second monochromator in such a way that the diffraction on a monocrystalline specimen can be made nondispersive.

V. V. Lider

1991-01-01

165

Comparison of Kodak DEF (Direct Exposure Film) Industrex CX and Industrex AX Films at Soft X-ray Wavelengths.  

National Technical Information Service (NTIS)

Kodak direct exposure film and the Kodak Industrex films CX and AX have been compared, using a DC X-ray source to generate 1.5 keV soft X-rays. Characteristic curves and detective quantum efficiencies as a function of incident X-ray flux are presented for...

A. Ridgeley N. L. Foster

1989-01-01

166

Residual strain gradient determination in metal matrix composites by synchrotron X-ray energy dispersive diffraction  

Microsoft Academic Search

An X-ray technique for the measurement of internal residual strain gradients near the continuous reinforcements of metal matrix\\u000a composites has been investigated. The technique utilizes high intensity white X-ray radiation from a synchrotron radiation\\u000a source to obtain energy spectra from small (10-3 mm3) volumes deep within composite samples. The energy peak positions satisfy Bragg’s law and allow determination of the

Todd A. Kuntz; Haydn N. G. Wadley; David R. Black

1993-01-01

167

X-Ray Spectra  

NSDL National Science Digital Library

In this activity, learners use simple materials to simulate the effect of X-rays in a safe way. Learners place a piece of window screen over a box and a cardboard pattern on top of the screen. They sprinkle sand over the area of the box. The sand simulates X-rays passing through the screen to the bottom of the box, except where they are blocked by the cardboard. Use this activity to demonstrate how X-rays create an image, including "soft" and shorter wavelength X-rays as well as X-rays from space.

Fetter, Neil

2007-01-01

168

Structural relaxation in amorphous Fe 40 Ni 40 P 14 B 6 studied by energy dispersive X-ray diffraction  

Microsoft Academic Search

The atomic structure and the structural relaxation of amorphous Fe40Ni40P14B6 alloy were studied using the energy dispersive X-ray diffraction method. It was demonstrated that the structure of the amorphous alloy can be determined self-consistently with high accuracy by this method. The results indicated that the structural relaxation is a highly collective process involving many atoms, and can be described in

T. Egami

1978-01-01

169

Structural relaxation in amorphous Fe 40 Ni 40 P 14 B 6 studied by energy dispersive X-ray diffraction  

Microsoft Academic Search

The atomic structure and the structural relaxation of amorphous Fe40Ni40P14B6 alloy were studied using the energy dispersive X-ray diffraction method. It was demonstrated that the structure of the amorphous\\u000a alloy can be determined self-consistently with high accuracy by this method. The results indicated that the structural relaxation\\u000a is a highly collective process involving many atoms, and can be described in

T. Egami

1978-01-01

170

Energy-dispersive X-ray diffraction studies of the texture in cold-rolled alpha-beta brass  

Microsoft Academic Search

It is shown that energy-dispersive X-ray diffraction can be used for simultaneous measurement of several pole figures and\\u000a that the accuracy is sufficient for the determination of the crystallite orientation distribution. The method is applied to\\u000a the study of the texture in Cu-43 wt % Zn duplex alpha-beta brass rolled to 80% reduction.

J. Szpunar; L. Gerward

1980-01-01

171

Energy-Dispersive X-Ray Fluorescence analysis of Haleakal? basalt adze quarry materials, Maui, Hawai‘i  

Microsoft Academic Search

One of Hawai‘i’s major prehistoric basalt adze quarries (SIHP 50-50-11-2510) is located in the summit region of Haleakal?, Maui. Situated at approximately 2750 m above sea level (9000 ft), the quarry shares a similar high-altitude setting with the Mauna Kea adze quarry on Hawai‘i Island. Adding to a growing Energy-Dispersive X-Ray Fluorescence (EDXRF) database for the Hawaiian Islands, we present the results

Melanie A. Mintmier; Peter R. Mills; Steven P. Lundblad

172

Energy dispersive x-ray spectroscopic analysis in a microscopic area of a grain in YBCO ceramic superconductor  

Microsoft Academic Search

In the YBCO ceramic superconductor family, there are many different phases such as Y-124, Y-125, Y-145 and Y-111. Here, we obtain phase information in a microscopic area using EDX, i.e. energy dispersive X-ray spectroscopic analysis. EDX analysis is a relatively new method for determining the atomic percentage of a specimen. Within a microscopic region, nearly 10 x 10 micron in

J. C. L. Chow; P. C. W. Fung

1994-01-01

173

Bulk and trace element analysis of spices: the applicability of k 0-standardization and energy dispersive X-ray fluorescence  

Microsoft Academic Search

Methodology has been developed for the bulk and trace element analysis of spices such as curry powder and turmeric powder originated from Sri Lanka by the k0-standardization method (INAA-k0) and by energy dispersive X-ray fluorescence (EDXRF). SRM 1572 citrus leaves was used to check the accuracy of the results obtained by the two nuclear techniques. The elements determined quantitatively in

Ranjith Jayasekera; Maria C. Freitas; Maria F. Araújo

2004-01-01

174

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

Microsoft Academic Search

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

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

2004-01-01

175

Bromide detection in blood using energy dispersive X-ray fluorescence; a chemical marker supportive of drowning in seawater  

Microsoft Academic Search

Energy dispersive X-ray fluorescence spectrometry (EDX) enables rapid, non-destructive, multi-elemental analysis. Using EDX, bromide was detected in seawater but not in freshwater. We applied EDX to the detection of bromide in cardiac blood from medico-legal autopsy cases to obtain additional evidence supportive of seawater drowning. Bromide was detected in the blood of 4 out of 10 victims drowned in seawater.

Motonori Takahashi; Hiroshi Kinoshita; Minori Nishiguchi; Hajime Nishio

2010-01-01

176

Monte Carlo simulation of the backscatter region in photon-excited energy dispersive X-ray fluorescence spectra  

Microsoft Academic Search

The backscatter region of energy-dispersive X-ray fluorescence spectra obtained by a typical radioisotope system is examined\\u000a in detail. A Monte Carlo simulation program which incorporates all the information on photon scattering processes including\\u000a electron momentum distributions in target atoms, form factors and scattering factors for the cross-sections is presented.\\u000a The program uses extensive variance reduction techniques and has the option

F. ARINff; R. P. Gardner

1979-01-01

177

Testing an Energy-Dispersive Counting-Mode Detector With Hard X-Rays From a Synchrotron Source  

Microsoft Academic Search

A counting-mode line detector has been evaluated at a synchrotron radiation source in order to assess its performance for imaging applications. The x-ray detector is based on 3 mm thick CdZnTe arrays with 1 mm pixel pitch and multi-threshold counting electronics. Data readout has been performed in threshold scan mode to provide maximum energy dispersion. The acquired energy spectra are

Christian Baumer; Gerhard Martens; Bernd Menser; Ewald Roessl; Jens-Peter Schlomka; Roger Steadman; Günter Zeitler

2008-01-01

178

Study of particulate pollutants in the air of Riyadh by energy dispersive X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

Particulate pollutants in air samples from different parts of the city of Riyadh, Saudi Arabia, were studied prior to the Gulf war, employing energy dispersive X-ray fluorescence technique. Eight significant elements were found. Particular attention was paid to the study of the pollutants Fe, Ni, Cu, Zn and Pb due to their potential toxicity. These results will be of interest given the changed conditions.

Raoof, S. A.; Al-Sahhaf, Maarib

179

Influence of poly( l -lysine) on the structure of dipalmitoylphosphatidylglycerol\\/water dispersions studied by X-ray scattering  

Microsoft Academic Search

The interaction between the negatively charged phospholipid DPPG and positively charged poly(l-lysine) (PLL) of different lengths was studied by X-ray scattering in the SAXS and WAXS region. As a reference pure DPPG\\u000a (Na salt) was investigated over a wide temperature range (?30 to 70°C). The phase behavior of DPPG in aqueous and in buffer\\/salt\\u000a dispersions showed a metastable subgel phase

G. Förster; C. Schwieger; F. Faber; T. Weber; A. Blume

2007-01-01

180

DEDXS: the differential energy-dispersive X-ray spectroscopy system and its use in electric field modulation studies  

Microsoft Academic Search

The original implementation of a differential energy-dispersive X-ray spectroscopy system and its application to electric field studies suffered from certain limitations. These have been overcome in a new design featuring four high-voltage phototransistor switches with very fast rise times arranged in a bridge configuration. The enhanced system has a 4-step duty cycle, can handle up to 5 kV and can

G. T. Addison; C. S. G. Cousins; S. M. Flood; M. Hamichi; R. E. Meads; F. Miners; B. J. Sheldon

1995-01-01

181

Rapid quantification of iron, copper and zinc in food premixes using energy dispersive X-ray fluorescence  

Microsoft Academic Search

A simple and rapid method for the determination of iron, copper and zinc in food premixes (used during human food processing) by energy dispersive X-ray fluorescence (XRF) has been established and validated using 25 samples. Reference values were obtained by inductively coupled plasma-optical emission spectroscopy after microwave acidic digestions. Studied samples presenting wide ranges of concentrations: Fe=500–35000mg\\/kg, Cu=50–4000mg\\/kg and Zn=700–32000mg\\/kg

Loïc Perring; Daniel Andrey; Daniel Hammer

2005-01-01

182

THE HE-RICH CORE-COLLAPSE SUPERNOVA 2007Y: OBSERVATIONS FROM X-RAY TO RADIO WAVELENGTHS  

SciTech Connect

A detailed study spanning approximately a year has been conducted on the Type Ib supernova (SN) 2007Y. Imaging was obtained from X-ray to radio wavelengths, and a comprehensive set of multi-band (w2m2w1u'g'r'i'UBVYJHK{sub s} ) light curves and optical spectroscopy is presented. A virtually complete bolometric light curve is derived, from which we infer a {sup 56}Ni mass of 0.06 M {sub sun}. The early spectrum strongly resembles SN 2005bf and exhibits high-velocity features of Ca II and H{alpha}; during late epochs the spectrum shows evidence of an ejecta-wind interaction. Nebular emission lines have similar widths and exhibit profiles that indicate a lack of major asymmetry in the ejecta. Late phase spectra are modeled with a non-LTE code, from which we find {sup 56}Ni, O, and total-ejecta masses (excluding He) to be 0.06, 0.2, and 0.42 M {sub sun}, respectively, below 4500 km s{sup -1}. The {sup 56}Ni mass confirms results obtained from the bolometric light curve. The oxygen abundance suggests that the progenitor was most likely a {approx}3.3 M {sub sun} He core star that evolved from a zero-age-main-sequence mass of 10-13 M {sub sun}. The explosion energy is determined to be {approx}10{sup 50} erg, and the mass-loss rate of the progenitor is constrained from X-ray and radio observations to be {approx}<10{sup -6} M {sub sun} yr{sup -1}. SN 2007Y is among the least energetic normal Type Ib SNe ever studied.

Stritzinger, Maximilian; Phillips, Mark M.; Boldt, Luis [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile)], E-mail: mstritzinger@lco.cl, E-mail: mmp@lco.cl, E-mail: lboldt@lco.cl (and others)

2009-05-01

183

A microsphere-based short-wavelength recombination x-ray laser  

SciTech Connect

We describe a scheme for obtaining very short wavelengths ({lambda} {similar to} 10{Angstrom}) in recombination lasers. The rapid cooling rates necessary to achieve population inversion during recombination are attained by adiabatic expansion of sub micron spheres. The lasing region is made up of many such spheres. The spheres are heated impulsively by a powerful picosecond laser. First, they ionize, then as they expand, they cool and recombine. We have calculated the optimum sphere size and initial temperature for maximum gain in the n = 3 to n = 2 transition of hydrogen-like ions of elements with atomic numbers, Z, between 10 and 30. Gain of about 10{sup 3}cm{sup {minus}1} is calculated in aluminum at 38.8{Angstrom}. Gain rapidly decreases with Z so that gain in titanium at 13.6{Angstrom} is about 40 cm{minus}1. We have calculated the required pump laser intensity and found it to be attainable with current lasers. The propagation of the pump through the gas'' of spheres is considered and the problems arising from pump scattering by the spheres are discussed.

Valeo, E.J.; Cowley, S.C.

1992-04-01

184

A microsphere-based short-wavelength recombination x-ray laser  

SciTech Connect

We describe a scheme for obtaining very short wavelengths ({lambda} {similar_to} 10{Angstrom}) in recombination lasers. The rapid cooling rates necessary to achieve population inversion during recombination are attained by adiabatic expansion of sub micron spheres. The lasing region is made up of many such spheres. The spheres are heated impulsively by a powerful picosecond laser. First, they ionize, then as they expand, they cool and recombine. We have calculated the optimum sphere size and initial temperature for maximum gain in the n = 3 to n = 2 transition of hydrogen-like ions of elements with atomic numbers, Z, between 10 and 30. Gain of about 10{sup 3}cm{sup {minus}1} is calculated in aluminum at 38.8{Angstrom}. Gain rapidly decreases with Z so that gain in titanium at 13.6{Angstrom} is about 40 cm{minus}1. We have calculated the required pump laser intensity and found it to be attainable with current lasers. The propagation of the pump through the ``gas`` of spheres is considered and the problems arising from pump scattering by the spheres are discussed.

Valeo, E.J.; Cowley, S.C.

1992-04-01

185

Energy dispersive x-ray fluorescence spectrometry for determination of twenty-six trace and two major elements in geochemical specimens  

Microsoft Academic Search

A method for analyzing geochemical specimens by energy dispersive x-ray fluorescence is described. The fact is used that at any given x-ray energy between adjacent major element absorption edges, both the reciprocal of the specimen mass absorption coefficient and the spectral background intensity vary linearly with the intensity of the Compton scattered excitation radiation. Hence, Compton scattered excitation radiation serves

Robert D. Giauque; Roberta B. Garrett; Lilly Y. Goda

1977-01-01

186

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

SciTech Connect

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

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

1996-07-01

187

A multiplatform code for the analysis of energy-dispersive X-ray fluorescence spectra  

NASA Astrophysics Data System (ADS)

A user friendly program for X-ray fluorescence analysis has been developed at the European Synchrotron Radiation Facility. The program allows interactive as well as batch processing of large data sets and it is particularly well suited for X-ray imaging. Its implementation of a complete description of the M shell is particularly helpful for analysis of data collected at low energies. The code is platform independent (Linux, Windows, MacOS X, Solaris …) and it is freely available for non-commercial use. Description of the algorithms used and practical examples are presented.

Solé, V. A.; Papillon, E.; Cotte, M.; Walter, Ph.; Susini, J.

2007-01-01

188

X-ray emission analysis of a plasma source using an yttrium and a mylar target for the generation of 2.48 nm wavelength microbeam  

NASA Astrophysics Data System (ADS)

In this work, the characteristics of X-ray beam generated from a plasma produced by focusing a Nd-Yag/glass laser beam on mylar or yttrium target were presented.For each target material, the conversion efficiencies of the soft X-ray emission in two different energy ranges, (i) 300-510 eV (almost coincident with the Water Window), (ii) 450-850 eV were measured. The experimental results of the conversion efficiencies will be utilized at the PLASMA-X laboratory of L'Aquila University for the realization of an intense monochromatic X-ray microbeam to be used in radiobiological and in transmission X-ray microscopy applications. In the presented experimental set-up, at the wavelength of 2.48 nm, a monochromatic soft X-rays beam was collected by multilayer spherical mirrors reflecting at an incidence angle close to the normal of the surface.The optical system geometry, the monochromatic beam intensity and the measures of efficiency of conversion of X-ray were described in this paper [5].

Palladino, Libero; Lorenzo, Ramon Gimenez De; Emilio, Maurizio Di Paolo; Limongi, Tania

2013-05-01

189

In-situ wavelength calibration and temperature control for the C-Mod high-resolution x-ray crystal imaging spectrometer  

Microsoft Academic Search

An x-ray crystal imaging spectrometer with high spectral and spatial resolution is currently being used on Alcator C-Mod to infer time histories of temperature and velocity profiles. An in-situ wavelength calibration using a 1 mum palladium filter in between the crystal and the detectors of choice is being proposed as a natural wavelength-marker using the transmission changes across the L-II

Luis F. Delgado-Aparicio; Y. Podpaly; M. L. Reinke; C. Gao; J. Rice; S. Scott; M. Bitter; K. Hill; P. Beiersdorfer; D. Johnson; J. R. Wilson

2010-01-01

190

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

SciTech Connect

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

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

1985-01-01

191

Time-resolved X-ray absorption spectroscopy using an energy dispersive optics: Strengths and limitations  

Microsoft Academic Search

X-ray Absorption Spectroscopy has undergone a great theoretical and experimental development in the last years. This technique has proved to be a powerful tool in elucidating huge number of questions in materials science. Great interest exists in time-resolved experiments achieved with extreme energy resolution and energy scale stability taking full advantage of the strong correlation between the stereochemical environment of

Alouin Fontaine; Elisabeth Dartyge; Jean Itie; Alain Jucha; Alain Polian; Helio Tolentino; Gerard Tourillon

192

EVOLUTION OF X-RAY AND FAR-ULTRAVIOLET DISK-DISPERSING RADIATION FIELDS  

SciTech Connect

We present new X-ray and far-ultraviolet (FUV) observations of T Tauri stars covering the age range 1-10 Myr. Our goals are to observationally constrain the intensity of radiation fields responsible for evaporating gas from the circumstellar disk and to assess the feasibility of current photoevaporation models, focusing on X-ray and UV radiation. We greatly increase the number of 7-10 Myr old T Tauri stars observed in X-rays by including observations of the well-populated 25 Ori aggregate in the Orion OB1a subassociation. With these new 7-10 Myr objects, we confirm that X-ray emission remains constant from 1 to 10 Myr. We also show, for the first time, observational evidence for the evolution of FUV radiation fields with a sample of 56 accreting and non-accreting young stars spanning 1 Myr to 1 Gyr. We find that the FUV emission decreases on timescales consistent with the decline of accretion in classical T Tauri stars until reaching the chromospheric level in weak T Tauri stars and debris disks. Overall, we find that the observed strength of high-energy radiation is consistent with that required by photoevaporation models to dissipate the disks in timescales of approximately 10 Myr. Finally, we find that the high-energy fields that affect gas evolution are not similarly affecting dust evolution; in particular, we find that disks with inner clearings, transitional disks, have similar levels of FUV emission as full disks.

Ingleby, Laura; Calvet, Nuria; Miller, Jon; Bergin, Edwin; Hartmann, Lee [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Hernandez, Jesus; Briceno, Cesar [Centro de Investigaciones de Astronomia (CIDA), Merida, 5101-A (Venezuela, Bolivarian Republic of); Espaillat, Catherine, E-mail: lingleby@umich.edu, E-mail: ncalvet@umich.edu, E-mail: jonmm@umich.edu, E-mail: ebergin@umich.edu, E-mail: lhartm@umich.edu, E-mail: jesush@cida.ve, E-mail: briceno@cida.ve, E-mail: cespaillat@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-78, Cambridge, MA 02138 (United States)

2011-04-15

193

A Soft X-ray Spectrometer using a Highly Dispersive Multilayer Grating  

Microsoft Academic Search

There is a need for higher resolution spectrometers as a tool for inelastic x-ray scattering. Currently, resolving power around R = 10,000 is advertised. Measured RIXS spectra are often limited by this instrumental resolution and higher resolution spectrometers using conventional gratings would be prohibitively large. We are engaged in a development program to build blazed multilayer grating structures for diffracting

Tony Warwick; Howard Padmore; Dmitriy Voronov; Valeriy Yashchuk

2010-01-01

194

X-ray spectrometry using polycapillary X-ray optics and position sensitive detector  

Microsoft Academic Search

Polycapillary X-ray optics (capillary X-ray lens) are now popular in X-ray fluorescence (XRF) analysis. Such an X-ray lens can collect X-rays emitted from an X-ray source in a large solid angle and form a very intense X-ray microbeam which is very convenient for microbeam X-ray fluorescence (MXRF) analysis giving low minimum detection limits (MDLs) in energy dispersive X-ray fluorescence (EDXRF).

Xunliang Ding; Jingdong Xie; Yejun He; Quili Pan; Yiming Yan

2000-01-01

195

Texture analysis of oxide dispersion strengthened (ODS) Fe alloys by X-ray and neutron diffraction  

NASA Astrophysics Data System (ADS)

The ferritic ODS alloys studied were obtained by mechanical alloying. This strengthening method is very attractive, in particular for nuclear applications. In order to ensure the alloy a good compromise between mechanical resistance and ductility at high temperatures, it is necessary to control the microstructure and in particular the evolution during the recrystallization. First, a preliminary study, performed by X ray diffraction and optical microscopy, shows several grain growth mechanisms ; in particular, the “abnormal” grain growth mechanism which conducts to a large grain size [1], [2]. After annealing (3600s at 1470^{circ}C), the 30% cold-worked (swaging) alloys exhibit an heterogeneous microstructure with a large grains size ( 200 to 500 ?m) in the heart and near the surface of the material when the intermediate zone is inhabited by small grains ( 1 ?m). Fora higher cold-work level (60%), large size grains are only present in the periphery of the material. On account of the large grain size and strong heterogeneity of the microstructure, texture analysis using laboratory x-ray beam in not well adapted and so we have decided to use neutron beam. The neutron diffraction texture analysis has been performed at the Laboratoire Léon Brillouin on the 6T1 diffractometer on 2 different rods of the alloy (corresponding to the reduction ratios of 30% and 60%). Specific samples have been machined to characterise separately the zones with a different microstructure. After deformation, the alloys exhibit a typical ?-fibre texture \\{ hkl \\} <1l0> whatever the area of the sample and the reduction ratio. After recrystallization, a very inhomogeneous texture is evidenced through the thickness of the sample, in particular for the rod deformed with a reduction ratio of 30% : in the heart and in the periphery of the rod, a “single-crystal” type texture is observed; the a fibre remains for the intermediate diameter of the rod. For the rod cold rolled with a reduction ratio of 60%, the ?-fibre keeps on the heart of the material and as in the precedent case, a “single-crystal” type texture is observed near the surface of the sample. EBSD measurements have been performed to explicit at a local scale this behaviour and in order to furnish some input data for the simulation of static recrystallization. Les aciers ferritiques avec dispersion d'oxydes étudiés sont obtenus par métallurgie des poudres, ce qui leur confère une résistance mécanique accrue à haute température notamment pour des applications nucléaires. La difficulté pour l'utilisation de tels alliages réside dans la maîtrise de leur microstructure au cours de l'élaboration en particulier durant la recristallisation. Une première étude en diffraction des rayons-x et en métallographie optique a permis de révéler différents mécanismes de croissance du grain lors de la recristallisation, notamment une croissance “anormale” conduisant à une taille de grain très importante [t], [2]. Après recuit (3600s à 1470^{circ}C), précédé par un écrouissage de 30% sur des barres (par martelage) on voit apparaître une microstructure hétérogène à gros grains ( 200 à 500 ?m) au coeur et en surface externe de la barre alors que la zone intermédiaire est peuplée de grains fins (sim 1 ?m). Pour un écrouissage plus élevé (60%), après le même recuit, on ne voit apparaître des gros grains qu'en périphérie de la barre. Pour ce type de microstructure fortement hétérogène et à gros grains, la diffraction des rayons-x pour l'analyse de texture est mal adaptée, ce qui nous a conduit à utiliser la diffraction des neutrons sur le diffractomètre 6TI du Laboratoire Léon Brillouin. Les deux matériaux, écrouis de 30% et 60%, ont été analysés en réalisant des échantillons particuliers permettant d'étudier séparément le coeur et la périphérie. Après déformation, les deux échantillons présentent une texture de fibre ? \\{ hkl \\} <1l0> en tout point de la barre. Après recristallisation, on retrouve une texture trè

Béchade, J. L.; Mathon, M. H.; Branger, V.; Réglé, H.; Alamo, A.

2002-07-01

196

[Simple quantitation of arsenic by energy dispersive fluorescence X-ray spectrometer using Reinsch's test].  

PubMed

We examined the clinical usefulness of the Reinsch's test for the detection of the small amounts of the heavy metals such as arsenic and mercury using the fluorescence X-ray spectrometry. We tried t o measure various kinds of biological samples, including serum, urine, and gastric contents using this method. 0.4 ml or 1 ml of hydrochloric acid were added to 2 ml of serum or 6 ml urine and gastric content, respectively, and a copper plate (5.0x 0.8 cm) was immersed into this solution. The mixture heated at 90 degrees C by a heating block for 30 minutes. After heating, the copper plate was washed with water and dried. The copper arsenide that stuck to the copper plate due to Reinsch's test dissolved by methanol/ammonia (8:2) solution at 60 degrees C for 15 minutes. A drop gave the solution to a filter paper fluorescence X-ray analysis and completely dried the filter paper, and applied to the fluorescence X-ray spectrometer. As a result, this method showed about 20 times high sensitivity in comparison with the measurement with condition of solution. The minimal detectable limits of rsenic was 0.4 ppm in serum and were 0.2 ppm in rine and gastric content. The calibration curve could be made for 0.5 to 50 ppm. It will take about 90 min for the measurement using this method for the detection of arsenic in biological samples. We showed the usefulness of the Reinsch's test using the fluorescence X-ray spectrometry in the clinical toxicology. PMID:15678930

Ozo, Yumiko; Yoshizawa, Mie; Murata, Atsuo; Shimazaki, Syuji; Kajiwara, Masahiro; Takagi, Tetsuya; Sato, Yoshinobu

2004-10-01

197

Wave-dispersive x-ray spectrometer for simultaneous acquisition of several characteristic lines based on strongly and accurately shaped Ge crystal  

SciTech Connect

Si and Ge are widely used as analyzing crystals for x-rays. Drastic and accurate shaping of Si or Ge gives significant advance in the x-ray field, although covalently bonded Si or Ge crystals have long been believed to be not deformable to various shapes. Recently, we developed a deformation technique for obtaining strongly and accurately shaped Si or Ge wafers of high crystal quality, and the use of the deformed wafer made it possible to produce fine-focused x-rays. In the present study, we prepared a cylindrical Ge wafer with a radius of curvature of 50 mm, and acquired fluorescent x-rays simultaneously from four elements by combining the cylindrical Ge wafer with a position-sensitive detector. The energy resolution of the x-ray fluorescence spectrum was as good as that obtained using a flat single crystal, and its gain was over 100. The demonstration of the simultaneous acquisition of high-resolution x-ray fluorescence spectra indicated various possibilities of x-ray spectrometry, such as one-shot x-ray spectroscopy and highly efficient wave-dispersive x-ray spectrometers.

Hayashi, Kouichi; Nakajima, Kazuo; Fujiwara, Kozo; Nishikata, Susumu [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

2008-03-15

198

X-ray and electron microscopy of actinide materials  

Microsoft Academic Search

Actinide materials demonstrate a wide variety of interesting physical properties in both bulk and nanoscale form. To better understand these materials, a broad array of microscopy techniques have been employed, including transmission electron microscopy (TEM), electron energy-loss spectroscopy (EELS), energy dispersive X-ray spectroscopy (EDXS), high-angle annular dark-field imaging (HAADF), scanning electron microscopy (SEM), wavelength dispersive X-ray spectroscopy (WDXS), electron back

Kevin T. Moore

2010-01-01

199

Dense close-packed phase of tin above 157 GPa observed experimentally via angle-dispersive x-ray diffraction  

NASA Astrophysics Data System (ADS)

A hexagonal close-packed (P63/mmc) phase of the group 14 element Sn has been observed using angle-dispersive x-ray diffraction. The phase transition proceeds from bcc?hcp above 157 GPa at 298 K via a first-order pathway, accompanied by a small decrease in unit-cell volume (0.2%). Both phases coexist up to 194 GPa. Ab initio random structure search calculations confirm that the hcp phase is the only candidate for another polymorph of Sn occurring in this pressure range, and predict a return to the bcc structure above 1.3 TPa.

Salamat, Ashkan; Garbarino, Gaston; Dewaele, Agnès; Bouvier, Pierre; Petitgirard, Sylvain; Pickard, Chris J.; McMillan, Paul F.; Mezouar, Mohamed

2011-10-01

200

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

SciTech Connect

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

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

2003-10-01

201

An energy-dispersive technique to measure x-ray coherent scattering form factors of amorphous materials  

NASA Astrophysics Data System (ADS)

The material-dependent x-ray scattering properties of amorphous substances such as tissues and phantom materials used in imaging are determined by their scattering form factors, measured as a function of the momentum transfer argument, x. Incoherent scattering form factors, Finc, are calculable for all values of x while coherent scattering form factors, Fcoh, cannot be calculated except at large x because of their dependence on long-range order. As a result, measuring Fcoh is very important to the developing field of x-ray scatter imaging. Previous measurements of Fcoh, based on crystallographic techniques, have shown significant variability, as these techniques are not optimal for amorphous materials. We have developed an energy-dispersive technique that uses a polychromatic x-ray beam and an energy-sensitive detector. We show that Fcoh can be measured directly, with no scaling parameters, by computing the ratio of two spectra: the first, measured at a given scattering angle and the second, the direct transmission spectrum with no scattering. Experiments have been constructed on this principle and used to measure Fcoh for water and polyethylene to explore the reliability of the technique. A 121 kVp x-ray spectrum and seven different scattering angles between 1.67 and 15.09° were used, resulting in a measurable range of x between 0.5 and 9.5 nm-1. These are the first measurements of Fcoh made without the need for a scaling factor. Resolution in x varies between 10% for small scattering angles and 2% for large scattering angles. Accuracy in Fcoh is shown to be strongly dependent on the precision of the experimental geometry and varies between 5% and 15%. Comparison with previous published measurements for water shows values of the average absolute relative difference between 8% and 14%.

King, B. W.; Johns, P. C.

2010-02-01

202

An energy-dispersive technique to measure x-ray coherent scattering form factors of amorphous materials.  

PubMed

The material-dependent x-ray scattering properties of amorphous substances such as tissues and phantom materials used in imaging are determined by their scattering form factors, measured as a function of the momentum transfer argument, x. Incoherent scattering form factors, F(inc), are calculable for all values of x while coherent scattering form factors, F(coh), cannot be calculated except at large x because of their dependence on long-range order. As a result, measuring F(coh) is very important to the developing field of x-ray scatter imaging. Previous measurements of F(coh), based on crystallographic techniques, have shown significant variability, as these techniques are not optimal for amorphous materials. We have developed an energy-dispersive technique that uses a polychromatic x-ray beam and an energy-sensitive detector. We show that F(coh) can be measured directly, with no scaling parameters, by computing the ratio of two spectra: the first, measured at a given scattering angle and the second, the direct transmission spectrum with no scattering. Experiments have been constructed on this principle and used to measure F(coh) for water and polyethylene to explore the reliability of the technique. A 121 kVp x-ray spectrum and seven different scattering angles between 1.67 and 15.09 degrees were used, resulting in a measurable range of x between 0.5 and 9.5 nm(-1). These are the first measurements of F(coh) made without the need for a scaling factor. Resolution in x varies between 10% for small scattering angles and 2% for large scattering angles. Accuracy in F(coh) is shown to be strongly dependent on the precision of the experimental geometry and varies between 5% and 15%. Comparison with previous published measurements for water shows values of the average absolute relative difference between 8% and 14%. PMID:20071771

King, B W; Johns, P C

2010-01-14

203

Two facets of the x-ray microanalysis at low voltage: The secondary fluorescence x-rays emission and the microcalorimeter energy-dispersive spectrometer  

Microsoft Academic Search

The best spatial resolution, for a microanalysis with a scanning electron microscope (SEND, is achieved by using a low voltage electron beam. But the x-ray microanalysis was developed for high electron beam energy (greater than 10 keV). Also, the specimen will often contain light and medium elements and the analyst will have to use a mixture of K, L, and

Hendrix Demers

2008-01-01

204

Total rate imaging with x-rays (TRIX)--a simple method of forming a non-projection x-ray image in the SEM using an energy dispersive detector and its application to biological specimens.  

PubMed

X-ray images can be formed in a conventional scanning electron microscope equipped with a Si(Li) energy dispersive spectrometer. All the x-ray events generated in the electron beam scanning process are synchronously displayed in the same manner as for dot maps. The quasi-digital image formed using Total Rate Imaging with X-rays (TRIX) exhibits good gray scale contrast and is dependent on topography, orientation and atomic number. Although this latter dependence is complex, it has been found useful in locating several types of inclusions in lung tissue (silicosis), human alveolar macrophages and cigarette smoke condensate. This is because of the greater depth of penetration of x-rays than backscattered electrons (BSE) usually used for such localizations in a matrix, and the negligible sensitivity of the Si(Li) detector to x-rays from an organic biological matrix. The optimum procedure is to use a combination of TRIX and BSE to investigate such specimens. PMID:7423121

Ingram, P; Shelburne, J D

1980-01-01

205

Residual strain gradient determination in metal matrix composites by synchrotron X-ray energy dispersive diffraction  

NASA Astrophysics Data System (ADS)

An X-ray technique for the measurement of internal residual strain gradients near the continuous reinforcements of metal matrix composites has been investigated. The technique utilizes high intensity white X-ray radiation from a synchrotron radiation source to obtain energy spectra from small (10-3 mm3) volumes deep within composite samples. The energy peak positions satisfy Bragg’s law and allow determination of the lattice parameter. As the probe volume is translated, the peaks of the spectra shift and are used to infer lattice spacing changes and thus strains with a precision of 10-3 to 10-4 (depending on the sample grain size/probe volume ratio). The viability of the technique has first been tested using a model system with 800 ?m A12O3 fibers and a commercial purity titanium matrix. For this system (which remained elastic on cooling), good agreement was observed between the measured residual radial and hoop strain gradients and those estimated from a simple elastic concentric cylinders model. The technique was then used to assess the strains near (SCS-6) silicon carbide fibers in a Ti-14Al-21Nb matrix after consolidation processing. Reasonable agreement between measured and calculated strains was seen provided the probe volume was located 50 ?m or more from the fiber/matrix interface. Close to the interface, the measured elastic strains were smaller than anticipated, due to relaxation of the residual stress by plasticity and radial cracking during sample cooling.

Kuntz, Todd A.; Wadley, Haydn N. G.; Black, David R.

1993-05-01

206

Wavelength separation of plus and minus orders of soft-x-ray-EUV multilayer-coated gratings at near-normal incidence  

Microsoft Academic Search

The validity of approximating the efficiency of a multilayer grating operating at close to normal incidence in the soft-X-ray-EUV range with a product of the relative grating efficiency by the reflectance of its multilayer coating has been studied by the rigorous integral method. The widely used approximated approach has until recently been considered accurate enough for analysis of short-wavelength normal-incidence

Leonid I. Goray; John F. Seely

2005-01-01

207

Final Report, DOE Award Number DE-FG02-02ER45964, Electromagnetic Properties of Matter at X-ray Wavelengths  

SciTech Connect

We report results of a collaborative study of photon and charged-particle interactions with matter between the University of Vermont and Argonne and Brookhaven National Laboratories. A major goal was to extend the study of electromagnetic properties of selected materials to as wide a spectral range as possible. This broad approach discloses systematic trends not apparent in isolated measurements and exploits the power of dispersion analysis and sum-rule constraints. Emphasis was largely on UV and X-ray processes and capitalized on the wide range of photon energies available at NSLS. A key finding is that, under favorable circumstances, dispersion theory relates dispersive processes (e.g. refractive index, dielectric constant) to spectral moments of absorptive processes. This appears to be a new method in optics; it yields significant simplifications and provides a precise, model-independent characterization of optical materials. Problems addressed included a) x-ray magnetooptics; b) UV/soft-x-ray processes in insulators and their contribution to visible dispersion; c) demonstration of moments/dispersion analysis in glasses and applications to fiber-optic systems; d) the optical constants of silicon and their application to the stopping power of silicon for charged-particles. Results include: ? Resolution of a long-standing conflict over the relation between x-ray Faraday rotation and x-ray magnetic circular dichroism. Specifically, the Kramers-Kronig relations must be generalized to account for the breaking of time-reversal symmetry by magnetic fields. Experimental reports to the contrary were shown to be inconclusive. Reanalysis of x-ray Faraday rotation data supports the generalization. ? Demonstration that the optical properties of dielectrics in their region of transparency are determined by a series expansion in spectral moments of the dielectric’s infrared and ultraviolet absorption spectra. Application of this to silicate glasses clarifies the role of glass modifiers in introducing charge-transfer, intra-ionic and perturbed-exciton transitions that combine to determine visible optical properties. Roughly, the refractive index is determined by the total electronic absorption, while dispersion depends on how the absorption is distributed. Materials characterization using UV/soft-x-ray moments may have application to non-destructive testing of glasses and high-temperature glass melts. ? Application of moments methods to pulse propagation in optical fibers showed that signal distortion is minimized at the carrier-wave frequency for which dispersion in group velocity caused by IR processes just cancels the dispersion caused by UV and soft-x-ray processes. ? Construction of a composite set of optical constants for silicon employing a method of self-consistent dispersion analysis from the extensive measurements available in the literature. This provides a reliable set of optical constants in the IR and visible, and has clarified the issue of scaling relative measurements at the K edge and the accuracy of measurements at the L edge. ? Direct calculation of the stopping power of silicon for charged particles as outlined by Bethe using our composite set of optical constants. This task was not previously feasible for want of accurate dielectric function data over a wide spectral range. This study resolved a long-standing conflict between measured average excitation energy or I values that was an issue for radiation damage and shielding applications.

Smith, David Y.

2007-02-28

208

Dispersion Trimming in a Reconfigurable Wavelength Selective Switch  

Microsoft Academic Search

We experimentally demonstrate dispersion compensation in a wavelength selective switch, and characterize the bandwidth-dispersion product. At a channel bit-rate of 80 Gbit\\/s, we compensate for various amounts of dispersion (up to ??60 ps\\/nm), tunable for each wavelength division multiplexed channel, solely by adjusting the phase front of the optical signal inside the wavelength selective switch. Error-free operation is obtained for

Steven Frisken; Jeremy A. Bolger; Dmitri Abakoumov; Glenn Baxter; Simon Poole; Benjamin J. Eggleton

2008-01-01

209

Determination of total contents of bromine, iodine and several trace elements in soil by polarizing energy-dispersive X-ray fluorescence spectrometry  

Microsoft Academic Search

A non-destructive analysis method for total bromine (Br) and iodine (I) contents in soil was established using polarizing energy-dispersive X-ray fluorescence (EDXRF) spectrometry. The matrix-corrected intensity of Br and I K? X-rays from pressed pellets of soil powder samples was calibrated with their contents measured by inductively coupled plasma (ICP)-mass spectrometry after pyrohydrolysis preparation. The calibration curves for Br and

Akira Takeda; Shin-ichi Yamasaki; Hirofumi Tsukada; Yuichi Takaku; Shun’ichi Hisamatsu; Noriyoshi Tsuchiya

2011-01-01

210

Hot electron and x-ray production from intense laser irradiation of wavelength-scale polystyrene spheres  

SciTech Connect

Hot electron and x-ray production from solid targets coated with polystyrene-spheres which are irradiated with high-contrast, 100 fs, 400 nm light pulses at intensity up to 2x10{sup 17} W/cm{sup 2} have been studied. The peak hard x-ray signal from uncoated fused silica targets is an order of magnitude smaller than the signal from targets coated with submicron sized spheres. The temperature of the x-rays in the case of sphere-coated targets is twice as hot as that of uncoated glass. A sphere-size scan of the x-ray yield and observation of a peak in both the x-ray production and temperature at a sphere diameter of 0.26 {mu}m, indicate that these results are consistent with Mie enhancements of the laser field at the sphere surface and multipass stochastic heating of the hot electrons in the oscillating laser field. These results also match well with particle-in-cell simulations of the interaction.

Sumeruk, H. A.; Kneip, S.; Symes, D. R.; Churina, I. V.; Belolipetski, A. V.; Dyer, G.; Landry, J.; Bansal, G.; Bernstein, A.; Donnelly, T. D.; Karmakar, A.; Pukhov, A.; Ditmire, T. [Texas Center for High Intensity Laser Science, Department of Physics, University of Texas, Austin, Texas 78712 (United States); Department of Physics, Harvey Mudd College, Claremont, California 91711 (United States); Institut fuer Theoretische Physik I, Heinrich-Heine-University of Dusseldorf, 40225 Dusseldorf (Germany); Texas Center for High Intensity Laser Science, Department of Physics, University of Texas, Austin, Texas 78712 (United States)

2007-06-15

211

Hot electron and x-ray production from intense laser irradiation of wavelength-scale polystyrene spheres  

NASA Astrophysics Data System (ADS)

Hot electron and x-ray production from solid targets coated with polystyrene-spheres which are irradiated with high-contrast, 100 fs, 400 nm light pulses at intensity up to 2×1017 W/cm2 have been studied. The peak hard x-ray signal from uncoated fused silica targets is an order of magnitude smaller than the signal from targets coated with submicron sized spheres. The temperature of the x-rays in the case of sphere-coated targets is twice as hot as that of uncoated glass. A sphere-size scan of the x-ray yield and observation of a peak in both the x-ray production and temperature at a sphere diameter of 0.26 ?m, indicate that these results are consistent with Mie enhancements of the laser field at the sphere surface and multipass stochastic heating of the hot electrons in the oscillating laser field. These results also match well with particle-in-cell simulations of the interaction.

Sumeruk, H. A.; Kneip, S.; Symes, D. R.; Churina, I. V.; Belolipetski, A. V.; Dyer, G.; Landry, J.; Bansal, G.; Bernstein, A.; Donnelly, T. D.; Karmakar, A.; Pukhov, A.; Ditmire, T.

2007-06-01

212

Multi-Wavelength Studies of X-ray selected BL Lacertae Objects: Implications for the Standard Model  

NASA Astrophysics Data System (ADS)

The results of our radio, optical, and X-ray observations of X-ray selected BL Lacertae objects (XBLs) are presented. Our radio observations reveal that: 1) XBLs possess kiloparsec-scale structures similar to those of nearby FR 1 radio galaxies. 2) XBLs are considerably less core-dominated than radio-selected BL Lacs (RBLs); 3) All but two XBLs for which radio polarimetry was done have 1-10% fractional polarization at 8 GHz, and 4) The correlations between polarization position angles in the radio and optical, as well as between optical polarization angles and radio structure, are fairly weak. Our new X-ray data confirm that XBLs are undergoing significant ``negative'' evolution; zero evolution is ruled out at better than 2 sigma . Interestingly, XBL spectra are significantly steeper (alpha ~ 1-2) than RBL spectra, suggesting a two-component model for BL Lac X-ray jets. Finally, a combined radio/optical/X-ray selection method is tested which is highly efficient in finding new BL Lacs. Thus far 24 of 27 objects selected as candidates by this method have been confirmed as BL Lacs. We also discuss the implications of this work for standard models which suggest BL Lac objects are beamed FR 1 radio galaxies.

Perlman, Eric S.

1993-12-01

213

Determination of trace elements in Syrian medicinal plants and their infusions by energy dispersive X-ray fluorescence and total reflection X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

X-ray fluorescence (XRF) and total-reflection X-ray fluorescence (TXRF) techniques suited well for a multi-element determination of K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr in some Syrian medicinal plant species. The accuracy and the precision of both techniques were verified by analyzing the Standard Reference Materials (SRM) peach-1547 and apple leaves-1515. A good agreement between the measured concentrations of the previously mentioned elements and the certified values were obtained with errors less than 10.7% for TXRF and 15.8% for XRF. The determination of Br was acceptable only by XRF with an error less than 24%. Furthermore, the XRF method showed a very good applicability for the determination of K, Ca, Mn, Fe, Cu, Zn, Rb, Sr, and Br in infusions of different Syrian medicinal plant species, namely anise ( Anisum vulgare), licorice root ( Glycyrrhiza glabra), and white wormwood ( Artemisia herba-alba).

Khuder, A.; Sawan, M. Kh.; Karjou, J.; Razouk, A. K.

2009-07-01

214

Residual strain gradient determination in metal matrix composites by synchrotron X-ray energy dispersive diffraction  

SciTech Connect

An X-ray technique for the measurement of internal residual strain gradients near the continuous reinforcements of metal matrix composites has been investigated. The technique utilizes high intensity white X-ray radiation from a synchrotron radiation source to obtain energy spectra from small (10[sup [minus]3] mm[sup 3]) volumes deep within composite samples. The energy peak positions satisfy Bragg's law and allow determination of the lattice parameter. As the probe volume is translated, the peaks of the spectra shift and are used to infer lattice spacing changes and thus strains with a precision of 10[sup [minus]3] to 10[sup [minus]4] (depending on the sample grain size/probe volume ratio). The viability of the technique has first been tested using a model system with 800 [mu]m Al[sub 2]O[sub 3] fibers and a commercial purity titanium matrix. For this system (which remained elastic on cooling), good agreement was observed between the measured residual radial and hoop strain gradients and those estimated from a simple elastic concentric cylinders model. The technique was then used to assess the strains near (SCS-6) silicon carbide fibers in a Ti-14Al-21Nb matrix after consolidation processing. Reasonable agreement between measured and calculated strains was seen provided the probe volume was located 50 [mu]m or more from the fiber/matrix interface. Close to the interface, the measured elastic strains were smaller than anticipated, due to relaxation of the residual stress by plasticity and radial cracking during sample cooling.

Kuntz, T.A. (APTECH Engineering Services, Inc., Sunnyvale, CA (United States)); Wadley, H.N.G. (Univ. of Virginia, Charlottesville (United States)); Black, D.R. (National Inst. of Standard and Tech., Gaithersburg, MD (United States))

1993-05-01

215

Efficient Excitation of Gain-Saturated Sub-9-nm-Wavelength Tabletop Soft-X-Ray Lasers and Lasing Down to 7.36 nm  

SciTech Connect

We have demonstrated the efficient generation of sub-9-nm-wavelength picosecond laser pulses of microjoule energy at 1-Hz repetition rate with a tabletop laser. Gain-saturated lasing was obtained at =8.85 nm in nickel-like lanthanum ions excited by collisional electron-impact excitation in a precreated plasma column heated by a picosecond optical laser pulse of 4-J energy. Furthermore, isoelectronic scaling along the lanthanide series resulted in lasing at wavelengths as short as =7.36 nm. Simulations show that the collisionally broadened atomic transitions in these dense plasmas can support the amplification of subpicosecond soft-x-ray laser pulses.

Alessi, David [Colorado State University, Fort Collins; Wang, Yong [Colorado State University, Fort Collins; Luther, Brad [Colorado State University, Fort Collins; Yin, Liang [Colorado State University, Fort Collins; Martz, Dale [Colorado State University, Fort Collins; Woolston, Mark [Colorado State University, Fort Collins; Liu, Yanwei [University of California, Berkeley & LBNL; Berrill, Mark A [ORNL; Jorge, Rocca [Colorado State University, Fort Collins

2011-01-01

216

A deconvolution approach for the enhancement of spatial resolution in energy dispersive x-ray diffraction and related imaging methods  

NASA Astrophysics Data System (ADS)

A reconstruction approach is presented, allowing the improvement of spatial resolution of images obtained by sequential pixel scanning techniques. Based on a series of measurements taken under different object positions, the signal contributions from individual voxels of significantly reduced size are calculated. Mathematically, the type of reconstruction used can be regarded as a deconvolution or solving an inverse problem. Due to the specific shape of the convolution kernel in the x-ray diffraction example treated here the problem turns out to be ill-posed, and thus its solution using measured (noisy) data requires the application of a suitable regularization method. Detailed studies on this issue led to the development of a novel iterative algorithm, combining several deconvolution runs with preceding and intermediate image processing steps. The Tikhonov method was used for regularization. Depending on the object under investigation, the original Euclidean norm (least-squares fit) was advantageously replaced by the 1-norm (least absolute deviation, LAD problem). The method presented here was developed to overcome resolution limitations in spatially resolved x-ray diffraction measurements on extended objects as used, e.g., for material analysis or the detection of illicit substances in baggage inspection applications. Nevertheless, the technique may easily be utilized for resolution enhancement within other imaging modalities, provided the task can be written as a deconvolution problem and the corresponding convolution kernel is known. According to the features of our experimental setup the developed reconstruction algorithm is explained for energy dispersive x-ray diffraction with pencil beam irradiation as an example application. The spatial resolution enhancement is demonstrated, using simulated and measured data sets corresponding to objects of different material composition.

Schlesinger, S.; Bomsdorf, H.

2013-07-01

217

Structure of the Short-Wavelength L-Series (X-Ray) Satellites (Struktura Korotkovolnovykh Satellitov L-Serii).  

National Technical Information Service (NTIS)

The work presents a calculation of the structure of the L-series x-ray satellites for Mo (Z = 42), emitted by atoms which are ionized simultaneously in the 2p and 3d shells. Since the structure of the L-series satellites is identical for Z > 32, the resul...

V. F. Demekhin A. P. Ganzha A. T. Kozakov I. Y. Kudryavtsev

1972-01-01

218

Gold nephropathy. Ultrastructural, fluorescent, and energy-dispersive x-ray microanalysis study  

SciTech Connect

The nephrotic syndrome developed in a patient receiving therapy with gold for rheumatoid arthritis. The results of a histopathological examination of the renal biopsy specimen were unremarkable. Immunofluorescent studies showed deposits of immunoglobulins and C3 in a granular pattern in the glomerular basement membranes. Ultrastructurally, the discrete osmiophilic immune complexes were epimembranous. By x-ray microanalysis, gold that was complexed with sulfur was present in proximal tubular cytoplasmic vacuoles and nuclei. Gold and sulfur could not be demonstrated in glomerular epimembranous deposits. The results of these studies suggest that immune complex deposition does not involve gold and sulfur acting as haptens. Gold-salt therapy may result in damage to proximal tubules that leak renal tubular antigens, which in turn complex with autoantibody and produce an autoimmune membranous nephropathy. The evidence for this mechanism is not convincing. Although the data indicate an immune-complex cause for gold-salt nephropathy, the incident antigen (or antigens) and mechanism of action remain unidentified.

Ainsworth, S.K.; Swain, R.P.; Watabe, N.; Brackett, N.C. Jr.; Pilia, P.; Hennigar, G.R.

1981-07-01

219

Energy dispersive x-ray analysis of the cornea. Application to paraffin sections of normal and diseased corneas  

SciTech Connect

The distribution of chemical elements in the normal human cornea was studied by energy dispersive x-ray analysis and scanning electron microscopy of routinely prepared paraffin sections. Calcium, phosphorus, and sulfur were consistently present in quantities above background and varied in concentration regionally. Analysis of fresh-frozen tissue, an approximation of the in vivo state, gave a similar elemental profile to paraffin sections, except for the loss of diffusable electrolytes in the latter. After fixation, S was the most abundant element and was highest in Descemet's membrane. Corneas with granular, lattice, macular, and Fuchs endothelial dystrophies, band keratopathy, and spheroidal degeneration were also examined. Characteristic patterns of abnormal S and Ca distribution were found in each of the dystrophies. The relative proportions of Ca, P, and S gave diagnostic profiles for distinguishing band keratopathy and spheroidal degeneration.

Robinson, M.R.; Streeten, B.W.

1984-11-01

220

Bromide detection in blood using energy dispersive X-ray fluorescence; a chemical marker supportive of drowning in seawater.  

PubMed

Energy dispersive X-ray fluorescence spectrometry (EDX) enables rapid, non-destructive, multi-elemental analysis. Using EDX, bromide was detected in seawater but not in freshwater. We applied EDX to the detection of bromide in cardiac blood from medico-legal autopsy cases to obtain additional evidence supportive of seawater drowning. Bromide was detected in the blood of 4 out of 10 victims drowned in seawater. In contrast, bromide concentrations were below the quantification limit in both victims from freshwater drowning and non-drowning controls. No postmortem invasion of bromide was observed in animal experiments of postmortem immersion in seawater. These results indicate that the detection of bromide in blood by EDX could be a chemical marker supportive of drowning in seawater. PMID:20335061

Takahashi, Motonori; Kinoshita, Hiroshi; Nishiguchi, Minori; Nishio, Hajime

2010-03-23

221

Findings for current marks: histopathological examination and energy-dispersive X-ray spectroscopy of three cases.  

PubMed

We describe herein three cases of electrocution. As most deaths caused by electricity are due to cardiac arrhythmia or paralysis of the respiratory muscles, autopsy findings in electrocution cases are generally non-specific, with the exception of the presence of current marks. We detected metallization by histological examination and energy-dispersive X-ray spectroscopy (EDX) analysis in tissues of typical or atypical current marks. In addition, myofiber break-up was observed in one case. One patient was hospitalized before death and revealed patchy contraction band necrosis, along with infiltration of leucocytes and vacuolation in the diaphragm. The presence of current marks is the hallmark for forensic diagnosis of electrocution. Although specific findings are lacking at autopsy in cases of electrocution, detailed histological examination and EDX analysis provide useful information for forensic diagnosis. PMID:23895763

Tanaka, Naoko; Kinoshita, Hiroshi; Jamal, Mostofa; Kumihashi, Mitsuru; Tsutsui, Kunihiko; Ameno, Kiyoshi

2013-07-26

222

X-ray beamsplitter  

DOEpatents

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

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

1989-01-01

223

Scanning electron microscopy/energy dispersive spectrometry fixedbeam or overscan x-ray microanalysis of particles can miss the real structure: x-ray spectrum image mapping reveals the true nature  

NASA Astrophysics Data System (ADS)

The typical strategy for analysis of a microscopic particle by scanning electron microscopy/energy dispersive spectrometry x-ray microanalysis (SEM/EDS) is to use a fixed beam placed at the particle center or to continuously overscan to gather an "averaged" x-ray spectrum. While useful, such strategies inevitably concede any possibility of recognizing microstructure within the particle, and such fine scale structure is often critical for understanding the origins, behavior, and fate of particles. Elemental imaging by x-ray mapping has been a mainstay of SEM/EDS analytical practice for many years, but the time penalty associated with mapping with older EDS technology has discouraged its general use and reserved it more for detailed studies that justified the time investment. The emergence of the high throughput, high peak stability silicon drift detector (SDD-EDS) has enabled a more effective particle mapping strategy: "flash" x-ray spectrum image maps can now be recorded in seconds that capture the spatial distribution of major (concentration, C > 0.1 mass fraction) and minor (0.01 <= C <= 0.1) constituents. New SEM/SDD-EDS instrument configurations feature multiple SDDs that view the specimen from widely spaced azimuthal angles. Multiple, simultaneous measurements from different angles enable x-ray spectrometry and mapping that can minimize the strong geometric effects of particles. The NIST DTSA-II software engine is a powerful aid for quantitatively analyzing EDS spectra measured individually as well as for mapping information (available free for Java platforms at: http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html).

Newbury, Dale E.; Ritchie, Nicholas W. M.

2013-05-01

224

Early multi-wavelength emission from gamma-ray bursts: from gamma-ray to x-ray  

Microsoft Academic Search

The study of the early high-energy emission from both long and short gamma-ray bursts (GRBs) has been revolutionized by the Swift mission. The rapid response of Swift shows that the non-thermal x-ray emission transitions smoothly from the prompt phase into a decaying phase whatever the details of the light curve. The decay is often categorized by a steep-to-shallow transition suggesting

P. T. O'Brien; R. Willingale; J. P. Osborne; M. R. Goad

2006-01-01

225

Multi-wavelength Studies of Spectacular Ram Pressure Stripping of a Galaxy: Discovery of an X-Ray Absorption Feature  

NASA Astrophysics Data System (ADS)

We report the detection of an X-ray absorption feature near the galaxy M86 in the Virgo cluster. The absorber has a column density of 2-3 × 1020 cm–2, and its position coincides with the peak of an intracluster H I cloud which was removed from the galaxy NGC 4388 presumably by ram pressure. These results indicate that the H I cloud is located in front of M86 along the line-of-sight, and suggest that the stripping was primarily created by an interaction between NGC 4388 and the hot plasmas of the Virgo cluster, not the M86 halo. By calculating an X-ray temperature map, we further detected an X-ray counterpart of the H I cloud up to ?3' south of M86. It has a temperature of 0.89 keV and a mass of ~4.5 × 108 M ?, exceeding the estimated H I gas mass. The high hot-to-cold gas ratio in the cloud indicates a significant evaporation of the H I gas, probably by thermal conduction from the hotter cluster plasma with a sub-Spitzer rate.

Gu, Liyi; Yagi, Masafumi; Nakazawa, Kazuhiro; Yoshida, Michitoshi; Fujita, Yutaka; Hattori, Takashi; Akahori, Takuya; Makishima, Kazuo

2013-11-01

226

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

SciTech Connect

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

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

2010-04-08

227

Time- and wavelength-resolved luminescence evaluation of several types of scintillators using streak camera system equipped with pulsed X-ray source  

NASA Astrophysics Data System (ADS)

To design new scintillating materials, it is very important to understand detailed information about the events, which occurred during the excitation and emission processes under the ionizing radiation excitation. We developed a streak camera system equipped with picosecond pulsed X-ray source to observe time- and wavelength-resolved scintillation events. In this report, we test the performance of this new system using several types of scintillators including bulk oxide/halide crystals, transparent ceramics, plastics and powders. For all samples, the results were consistent with those reported previously. The results demonstrated that the developed system is suitable for evaluation of the scintillation properties.

Furuya, Yuki; Yanagida, Takayuki; Fujimoto, Yutaka; Yokota, Yuui; Kamada, Kei; Kawaguchi, Noriaki; Ishizu, Sumito; Uchiyama, Koro; Mori, Kuniyoshi; Kitano, Ken; Nikl, Martin; Yoshikawa, Akira

2011-04-01

228

Energy dispersive x-ray absorption spectroscopy for studies of catalysts in solution  

NASA Astrophysics Data System (ADS)

The millisecond time resolution achieved by Energy Dispersive EXAFS (EDE) and the high stability provided by the unmoved optical components make this technique very attractive to study chemical reactions and elucidate reactive intermediate species. Great progress has been made on the EDE study of the problematic in situ experiments of reactions in solution. Herein, limitations and solutions for the study of these systems are given. Two examples of catalytic reactions followed in situ and carried out in a stopped-flow/UV-Vis spectroscopy/EDE set-up are shown.

Guilera, G.; Smolentsev, G.; Soldatov, A. V.; Hii, M.; Benfatto, M.; Newton, M. A.; Pascarelli, S.

2009-11-01

229

Determination of Cadmium, Chromium, Lead, and Mercury in Polyethylene and Polypropylene after Xylene Treatment by Energy Dispersive X-Ray Fluorescence Spectrometry  

Microsoft Academic Search

A convenient organic solvent treatment method was developed for the determination of Cd, Cr, Hg, and Pb in polyethylene and polypropylene matrices by energy dispersive X-ray fluorescence spectrometry. The solvent treatment method had many advantages for the fast, simple, and accurate multi-element analysis of these materials. Calibration curves were prepared using organometallic compounds in xylene in the concentration range of

Elif Tümay Özer; M. Akif Çimenoglu; Seref Güçer

2011-01-01

230

Identification of pure liquid precursor chemicals based on coherence function and fourier transform using energy dispersive X-ray diffraction scattering  

Microsoft Academic Search

A new method based on Fourier transform and coherence function was used to identify pure liquid precursor chemicals in this paper. Feature scattering spectra of several kinds of pure liquid precursor chemicals were detected through energy-dispersive X-ray scattering (EDXRS). These spectra, each of which was unique to particular liquid in the same case, were processed with coherence function after truncation

Dingjun Qu; Daoyang Yu; Wei Li; Yu Zhang; Bai Sun; Yu Zhong; Minqiang Li; Jinhuai Liu

2010-01-01

231

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

Microsoft Academic Search

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

P. K. Rose; J. Rowe

1987-01-01

232

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

Microsoft Academic Search

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

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

1998-01-01

233

Determination of the sequence of intersecting lines from laser toner and seal ink by Fourier transform infrared microspectroscopy and scanning electron microscope \\/ energy dispersive X-ray mapping  

Microsoft Academic Search

The aim of this study was to verify that the combination of Fourier transform infrared microspectroscopy and scanning electron microscope \\/ energy dispersive X-ray mapping could be applied to line intersection problems. The spectral data of red seal ink, laser toner and their intersections, such as peak location and peak intensity, were described. Relative peak height ratios of different chemical

Yuanfeng Wang; Bing Li

234

Time-series, Multi-wavelength Monitoring Of The High Mass X-ray Binary 4U 2206+54  

NASA Astrophysics Data System (ADS)

The high mass X-ray binary 4U 2206+54 has been a very controversial system. Optical time-series observations of this system from West Mountain Observatory and the Orson Pratt Observatory were analyzed to determine a more accurate orbital period. The summers of 2008 and 2009 provided a total of 55 nights of observations in the Johnson V filter. The summer of 2010 provided 20 nights of observations in Johnson BVRI. We present our preliminary results as of October 1, 2010 as well as the error analysis for the data. We also acknowledge NSF grant AST-0618209 for data collected from the West Mountain 36” telescope.

Bugno, Jessica L.; Hintz, E. G.; Joner, M. D.; Laney, C. D.

2011-01-01

235

Assignment of Individual Metal Redox States in a Metalloprotein By Crystallographic Refinement at Multiple X-Ray Wavelengths  

SciTech Connect

A method is presented to derive anomalous scattering contributions for individual atoms within a protein crystal by collecting several sets of diffraction data at energies spread along an X-ray absorption edge of the element in question. The method has been applied to a [2Fe:2S] ferredoxin model system with localized charges in the reduced state of the iron-sulfur cluster. The analysis shows that upon reduction the electron resides at the iron atom closer to the protein surface. The technique should be sufficiently sensitive for more complex clusters with noninteger redox states and is generally applicable given that crystals are available.

Einsle, O.; Andrade, S.L.A.; Dobbek, H.; Meyer, J.; Rees, D.C.; /Gottingen U. /Bayreuth U. /DRDC, Grenoble /Caltech

2007-07-09

236

Thermal Stability of Normal Incidence Multilayer Mirrors for the X-Ray Wavelength near Carbon K-Edge.  

PubMed

Annealing effects in the short-period multilayers Cr3C2/C, TiC/C, Cr3C2/(B + C), and CrB2/C were studied in a wide temperature range ~200-1200°C by x-ray scattering and cross-sectional electron microscopy. It was shown that the thermodynamic equilibrium of the layer materials at their interfaces and stabilization of layer structure by impurities and heat treatment are effective approaches to short-period multilayers with enhanced thermal stability of their structure and optical properties. PMID:21307501

Bugaev, E A; Fedorenko, A I; Kondratenko, V V; Zubarev, E N

1995-01-01

237

Thermal stability of normal incidence multilayer mirrors for x-ray wavelength near carbon K-edge  

NASA Astrophysics Data System (ADS)

Annealing effects in short-period multilayers Cr3C2/C, TiC/C, Cr3C2/(B+C) and CrB2/C were studied in wide temperature range approximately equals 200-1200 degree(s)C by X-ray scattering and cross-sectional microscopy. It was shown that thermodynamic equilibrium of layers materials at their interfaces and stabilization of layer structure by impurities and heat treatment are effective approaches to short-period multilayers with enhanced thermal stability of their structure and optical properties.

Bugaev, E. A.; Fedorenko, Anatoly I.; Kondratenko, V. V.; Zubarev, E. N.

1995-01-01

238

Mössbauer and energy-dispersive x-ray-diffraction studies of the pressure-induced crystallographic phase transition in C-type Yb2O3  

Microsoft Academic Search

The high-pressure behavior of the cubic C-type Yb2O3 was investigated by 170Yb Mössbauer spectroscopy and energy-dispersive x-ray diffraction. The room-temperature x-ray-diffraction data show that C-Yb2O3 transforms to the monoclinic B-type structure above 13 GPa. The equation of state of both C- and B-type phases was derived from these experiments. Mössbauer measurements up to 20 GPa were carried out at 4.2

C. Meyer; J. P. Sanchez; J. Thomasson; J. P. Itié

1995-01-01

239

The compressibility of FeO measured by energy dispersive X-ray diffraction in a diamond anvil squeezer up to 200 kbar  

Microsoft Academic Search

The compressibility of Fe0.941O has been measured by energy-dispersive X-ray diffraction methods in a diamond anvil squeezer up to 200 kbar. The data points can be described by the Murnaghan equation with K0=1,540±50 kbar and K'=4. An analysis of previous investigations, X-ray diffraction and ultrasonic measurements yields for the general composition Fe1-xO a regression line K0=5,438(1-x)-3,595 kbar for all known

G. Will; E. Hinze; W. Nuding

1980-01-01

240

X-ray calorimeters  

NASA Astrophysics Data System (ADS)

X-ray calorimeter instruments for astrophysics have seen rapid development since they were invented in 1984. The prime instrument on all currently planned X-ray spectroscopic observatories is based on calorimeter technology. This relatively simple detection concept that senses the energy of an incident photon by measuring the temperature rise of an absorber material at very low temperatures can form the basis of a very high-performance, non-dispersive spectrometer. State-of-theart calorimeter instruments have resolving powers of over 3000, large simultaneous bandpasses, and near unit efficiency. This coupled with the intrinsic imaging capability of a pixilated X-ray calorimeter array, allows true spectral-spatial instruments to be constructed. This chapter briefly reviews the detection scheme, the state of the art in X-ray calorimeter instruments and the future outlook for this technology.

Porter, F. Scott

241

Sample mass determination using Compton- and total scattered excitation radiation for energy-dispersive x-ray fluorescent analysis of trace elements in soft tissue specimens.  

PubMed

Compton profiles and total scattered intensities have been measured to determine the total sample mass, analyzed by an x-ray probe energy-dispersive analyzer. Under photon excitation, fluorescent x rays are emitted from the trace elements in a biological matrix. From incident radiation, the number of photons which are Commpton and elastically scattered by low-atomic-number elements is directly proportional to the total specimen mass. Tissue specimen masses have been measured from Compton intensities using Zr Kalpha and Ma Kalpha excitation x rays and mass calibration standards based upon carbon scattering. This procedure has been extended to include lower-energy excitation radiation, such as Cu, where the resolution of an energy-dispersion system requires that the total scattered intensity be used to determine the sample mass. Trace element weight-fraction concentrations are determined from this scheme with precisions of 1% in 2%, relying only upon information contained in the energy-dispersive x-ray spectrum. By adjusting for the difference between tissue and corbon scattering the accuracy of the elemental weight-fraction concentrations is brought to within 10% of elemental concentrations measured by atomic absorption spectroscopy, for samples weighing up to 25 mg. In the case of heavier samples, absorption corrections are necessary to achieve this accuracy. PMID:850514

Cox, H L; ong, P S

242

Application of Energy Dispersive X-Ray Fluorescence Spectroscopy to the Analysis of Contaminants in Fuels and Lubricants.  

National Technical Information Service (NTIS)

A rapid and inexpensive x-ray fluorescence spectroscopic method for the analysis of particulate contaminants has been developed. The method employs the collection of the particulates by filtration followed by x-ray fluorescence analysis of the filter. A u...

M. K. Greenberg F. M. Newman

1978-01-01

243

THIN-FILM DENSITY DETERMINATION OF TANTALUM, TANTALUM OXIDES, AND XEROGELS BY MULTIPLE RADIATION ENERGY DISPERSIVE X-RAY REFLECTIVITY  

EPA Science Inventory

X-ray reflectivity provides a nondestructive technique for measuring density in thin films. A conventional laboratory, Bragg-Brentano geometry diffractometer was employed to show the generalized feasibility of this technique. X-ray tubes with chromium, copper, and molybdenum targ...

244

Experiment of Si target ablation with soft X-ray laser operating at a wavelength of 46.9 nm  

NASA Astrophysics Data System (ADS)

We successfully ablated the Si target by the focused beam of capillary-discharge pumped laser at 46.9 nm. The laser of ˜50 ?J was focused by the sagittal surface of the cylinder mirror at grazing incidence. Fluences of the focused beam were varied by changing the distance between the mirror and target, and clear ablation patterns were obtained. The shapes of the patterns were consistent with the results simulated by ZEMAX software. The irradiance of the focal spot was simulated as well. Each pattern was ablated by 200 shots and the sampling distance between any two contiguous ablation positions was 0.7 cm. The peak value of energy density of the focal spot was estimated to be 7.48×10-3 J/cm2. According to the ablation pattern, the focal point of the mirror was determined. The experiment provides reliable data and focusing method for interaction of X-ray laser with solid target.

Cui, Huaiyu; Zhao, Yongpeng; Jiang, Shan; Xu, Miao; Wu, Han; Wang, Qi

2013-03-01

245

Multiple Epoch Analysis of the Guitar Nebula and B2224+65 at Optical, X-Ray, and Radio Wavelengths  

NASA Astrophysics Data System (ADS)

The Guitar Nebula is created by the interaction of the pulsar B2224+65 with the interstellar medium. We present multi-epoch observations of the nebula with the Hubble Space Telescope (HST) and the Chandra X-Ray Observatory (CXO), along with preliminary astrometric observations of B2224+65 with the Very Long Baseline Array (VLBA). The Guitar Nebula was observed in H-alpha by HST with WFPC2 (1994, 2001) and ACS (2006). The tip of the nebula head has expanded along the proper motion vector of the pulsar. Meanwhile, the sides and back of the head appear to be confined, possibly due to a density gradient in the ISM. Observations with CXO ACIS reveal an X-ray jet whose tip is coincident with the location of the pulsar, but at an angle of ~118° from the proper motion vector with a length of ~2 arcmin. Using data from 2000 and 2006, we imaged the jet at 0.3--10 keV. We did not find significant differences in the jet location or morphology between the two epochs, but our results are limited by the observation signal-to-noise ratio. PSR B2224+65 is one of the targets of PSR?, an ongoing VLBA campaign to measure pulsar proper motions and parallaxes. When completed in 2013, PSR? will provide both a distance and transverse velocity for PSR B2224+65 with very high precision. Based on a preliminary analysis of 5 epochs already observed, we confirm that the proper motion of the nebula tip measured with HST matches the pulsar proper motion measured with the VLBA. This project was conducted at Cornell University’s Astronomy REU program, with funding provided by the NSF.

Gautam, Abhimat; Chatterjee, S.; Cordes, J. M.; Deller, A. T.; LAZIO, J.

2013-01-01

246

The detection of food soils on stainless steel using energy dispersive X-ray and Fourier transform infrared spectroscopy.  

PubMed

Organic soiling is a major issue in the food processing industries, causing a range of biofouling and microbiological problems. Energy dispersive X-ray (EDX) and Fourier transform infra red spectroscopy (FT-IR) were used to quantify and determine the biochemical groups of food soils on stainless steel surfaces. EDX quantified organic material on surfaces where oily based residues predominated, but was limited in its usefulness since other food soils were difficult to detect. FT-IR provided spectral 'fingerprints' for each of the soils tested. Key soiling components were associated with specific peaks, viz. oils at 3025 cm(-1)-3011 cm(-1), proteins at 1698 cm(-1)-1636 cm(-1) and carbohydrates at 1658 cm(-1)-1596 cm(-1), 783 cm(-1)-742 cm(-1). High concentrations of some soils (10%) were needed for detection by both EDX and FT-IR. The two techniques may be of use for quantifying and identifying specific recalcitrant soils on surfaces to improve cleaning and hygiene regimes. PMID:21882897

Whitehead, K A; Benson, P S; Verran, J

2011-09-01

247

Solvent influences on metastable polymorph lifetimes: real-time interconversions using energy dispersive X-ray diffractometry.  

PubMed

Solvent influences on the crystallization of polymorph and hydrate forms of the nootropic drug piracetam (2-oxo-pyrrolidineacetamide) were investigated from water, methanol, 2-propanol, isobutanol, and nitromethane. Crystal growth profiles of piracetam polymorphs were constructed using time-resolved diffraction snapshots collected for each solvent system. Measurements were performed by in situ energy dispersive X-ray diffraction recorded in Station 16.4 at the synchrotron radiation source (SRS) at Daresbury Laboratory, CCLRC UK. Crystallizations from methanol, 2-propanol, isobutanol, and nitromethane progressed in a similar fashion with the initial formation of form I which then converted relatively quickly to form II with form III being generated upon further cooling. However, considerable differences were observed for the polymorphs lifetime and both the rate and temperature of conversion using the different solvents. The thermodynamically unstable form I was kinetically favored in isobutanol and nitromethane where traces of this polymorph were observed below 10 degrees C. In contrast, the transformation of form II and subsequent growth of form III were inhibited in 2-propanol and nitromethane solutions. Aqueous solutions produced hydrate forms of piracetam which are different from the reported monohydrate; this crystallization evolved through successive generation of transient structures which transformed upon exchange of intramolecular water between the liquid and crystalline phases. PMID:17455330

DeMatos, Luciana L; Williams, Adrian C; Booth, Steven W; Petts, Catherine R; Taylor, David J; Blagden, Nicholas

2007-05-01

248

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

PubMed

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

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

1994-01-01

249

Faults and foibles of quantitative scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS)  

NASA Astrophysics Data System (ADS)

Scanning electron microscopy with energy dispersive x-ray spectrometry (SEM/EDS) is a powerful and flexible elemental analysis method that can identify and quantify elements with atomic numbers > 4 (Be) present as major constituents (where the concentration C > 0.1 mass fraction, or 10 weight percent), minor (0.01<= C <= 0.1) and trace (C < 0.01, with a minimum detectable limit of ~+/- 0.0005 - 0.001 under routine measurement conditions, a level which is analyte and matrix dependent ). SEM/EDS can select specimen volumes with linear dimensions from ~ 500 nm to 5 ?m depending on composition (masses ranging from ~ 10 pg to 100 pg) and can provide compositional maps that depict lateral elemental distributions. Despite the maturity of SEM/EDS, which has a history of more than 40 years, and the sophistication of modern analytical software, the method is vulnerable to serious shortcomings that can lead to incorrect elemental identifications and quantification errors that significantly exceed reasonable expectations. This paper will describe shortcomings in peak identification procedures, limitations on the accuracy of quantitative analysis due to specimen topography or failures in physical models for matrix corrections, and quantitative artifacts encountered in xray elemental mapping. Effective solutions to these problems are based on understanding the causes and then establishing appropriate measurement science protocols. NIST DTSA II and Lispix are open source analytical software available free at www.nist.gov that can aid the analyst in overcoming significant limitations to SEM/EDS.

Newbury, Dale E.; Ritchie, Nicholas W. M.

2012-05-01

250

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

NASA Astrophysics Data System (ADS)

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

Baker, John

1991-05-01

251

Investigation of x-ray photon counting using a silicon-PIN diode and its application to energy-dispersive computed tomography  

NASA Astrophysics Data System (ADS)

X-ray photon counting was performed using a readymade silicon-PIN photodiode (Si-PIN-PD) at tube voltages ranging from 42 to 60 kV, and X-ray photons are directly detected using the 100 MHz Si-PIN-PD without a scintillator. Photocurrent from the diode is amplified using charge-sensitive and shaping amplifiers. Using a multichannel analyzer, X-ray spectra at a tube voltage of 60 kV could easily be measured. The photon-counting computed tomography (PCCT) is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan. In the PC-CT, we confirmed the energy-dispersive effect with changes in lower-level voltage of the event pulse using a comparator.

Kodama, Hajime; Sato, Eiichi; Sagae, Michiaki; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sato, Shigehiro; Ogawa, Akira

2013-09-01

252

Influence of poly(L-lysine) on the structure of dipalmitoylphosphatidylglycerol/water dispersions studied by X-ray scattering.  

PubMed

The interaction between the negatively charged phospholipid DPPG and positively charged poly(L: -lysine) (PLL) of different lengths was studied by X-ray scattering in the SAXS and WAXS region. As a reference pure DPPG (Na salt) was investigated over a wide temperature range (-30 to 70 degrees C). The phase behavior of DPPG in aqueous and in buffer/salt dispersions showed a metastable subgel phase at low temperatures and a recrystallization upon heating before reaching the liquid-crystalline phase. The presence of additional salt stabilizes the bilayer structure and decreases the recrystallization temperature. Large changes in the SAXS region are not connected with changes in chain packing. In DPPG/PLL samples, the PLL is inserted between adjacent headgroup layers and liberates counterions which give rise to a freezing point depression. In the complex with DPPG PLL form an alpha-helical secondary structure at pH 7 and temperatures below the gel to liquid-crystalline phase transition. This prevents DPPG from recrystallization and strongly increases the stacking order. The lamellar repeat distance is decreased and fixed by the helix conformation of PLL in the gel phase. PLL with n = 14 is too short to form helices and is squeezed out reversibly from the interbilayer space upon cooling by freezing of trapped water. In dispersions with longer PLLs (n > 400) at -20 degrees C a 1D crystallization of PLL alpha-helices in the aqueous layer between the headgroups takes place. A structural model is presented for the lateral periodic complex, which is similar to the known cationic lipid/DNA complex. PMID:16909276

Förster, G; Schwieger, C; Faber, F; Weber, T; Blume, A

2006-08-15

253

Trace elements as tumor biomarkers and prognostic factors in breast cancer: a study through energy dispersive x-ray fluorescence  

PubMed Central

Background The application and better understanding of traditional and new breast tumor biomarkers and prognostic factors are increasing due to the fact that they are able to identify individuals at high risk of breast cancer, who may benefit from preventive interventions. Also, biomarkers can make possible for physicians to design an individualized treatment for each patient. Previous studies showed that trace elements (TEs) determined by X-Ray Fluorescence (XRF) techniques are found in significantly higher concentrations in neoplastic breast tissues (malignant and benign) when compared with normal tissues. The aim of this work was to evaluate the potential of TEs, determined by the use of the Energy Dispersive X-Ray Fluorescence (EDXRF) technique, as biomarkers and prognostic factors in breast cancer. Methods By using EDXRF, we determined Ca, Fe, Cu, and Zn trace elements concentrations in 106 samples of normal and breast cancer tissues. Cut-off values for each TE were determined through Receiver Operating Characteristic (ROC) analysis from the TEs distributions. These values were used to set the positive or negative expression. This expression was subsequently correlated with clinical prognostic factors through Fisher’s exact test and chi-square test. Kaplan Meier survival curves were also evaluated to assess the effect of the expression of TEs in the overall patient survival. Results Concentrations of TEs are higher in neoplastic tissues (malignant and benign) when compared with normal tissues. Results from ROC analysis showed that TEs can be considered a tumor biomarker because, after establishing a cut-off value, it was possible to classify different tissues as normal or neoplastic, as well as different types of cancer. The expression of TEs was found statistically correlated with age and menstrual status. The survival curves estimated by the Kaplan-Meier method showed that patients with positive expression for Cu presented a poor overall survival (p?

2012-01-01

254

Dispersive micro solid-phase extraction using multiwalled carbon nanotubes for simultaneous determination of trace metal ions by energy-dispersive X-ray fluorescence spectrometry.  

PubMed

A methodology based on dispersive micro solid-phase extraction (DMSPE) using multiwalled carbon nanotubes (MWCNTs) as solid sorbent prior to measurement with energy-dispersive X-ray fluorescence (EDXRF) spectrometry is proposed. The procedure consists of chelating of nickel, cobalt, copper, and lead ions with ammonium pyrrolidinedithiocarbamate (APDC) and posterior adsorption of metal chelates on MWCNTs (1 mg) dispersed in the aqueous samples (100 mL). DMSPE promotes immediate interaction between the metal chelates and MWCNTs and shortens time of sample preparation in comparison with classical solid-phase extraction. After microextraction process, MWCNTs are collected onto filter and directly measured by EDXRF. With this technique, the direct quantification of metal species held in solid materials is possible and, therefore, the elution step can be avoided. The effects of various experimental parameters such as pH of the solution, amounts of MWCNTs and APDC, sample volume, and time of stirring were investigated. With the best analytical conditions (1 mg of MWCNTs, 2 mg of APDC, 100 mL sample volume, pH = 7, and 5 min time of stirring), Co(II), Ni(II), Cu(II), and Pb(II) can be simultaneously determined with very good recoveries (101%, 98%, 96%, 99%, respectively) and detection limits (0.43, 0.11, 0.46, 0.15 ng mL(-1), respectively). The method was applied in determination of trace metal ions in tap water and wastewater samples. PMID:23622440

Skorek, Robert; Zawisza, Beata; Marguí, Eva; Queralt, Ignasi; Sitko, Rafal

2013-02-01

255

Survey of Ti-, B-, and Y-based soft x-ray-extreme ultraviolet multilayer mirrors for the 2- to 12-nm wavelength region.  

PubMed

We have performed an experimental investigation of Ti-, B(4)C-, B-, and Y-based multilayer mirrors for the soft x-ray¿extreme ultraviolet (XUV) wavelength region between 2.0 and 12.0 nm. Eleven different material pairs were studied: Ti/Ni, Ti/Co, Ti/Cu, Ti/W, B(4)C/Pd, B/Mo, Y/Pd, Y/Ag, Y/Mo, Y/Nb, and Y/C. The multilayers were sputter deposited and were characterized with a number of techniques, including low-angle x-ray diffraction and normal incidence XUV reflectometry. Among the Ti-based multilayers the best results were obtained with Ti/W, with peak reflectances up to 5.2% at 2.79 nm at 61° from normal incidence. The B(4)C/Pd and B/Mo multilayer mirrors had near-normal incidence (5°) peak reflectances of 11.5% at 8.46 nm and 9.4% at 6.67 nm, respectively, whereas a Y/Mo multilayer mirror had a maximum peak reflectance of 25.6% at 11.30 nm at the same angle. The factors limiting the peak reflectance of these different multilayer mirrors are discussed. PMID:21102948

Montcalm, C; Kearney, P A; Slaughter, J M; Sullivan, B T; Chaker, M; Pépin, H; Falco, C M

1996-09-01

256

Survey of Ti-, B-, and Y-based soft x-ray -extreme ultraviolet multilayer mirrors for the 2- to 12-nm wavelength region  

NASA Astrophysics Data System (ADS)

We have performed an experimental investigation of Ti-, B4C-, B-, and Y-based multilayer mirrors for the soft x-ray-extreme ultraviolet (XUV) wavelength region between 2.0 and 12.0 nm. Eleven different material pairs were >C/Pd, B/Mo, Y/Pd, Y/Ag, Y/Mo, Y/Nb, and Y/C. The multilayers were sputter deposited and were characterized with a number of techniques, including low-angle x-ray diffraction and normal incidence XUV reflectometry. Among the Ti-based multilayers the best results were obtained with Ti/W, with peak reflectances up to 5.2% at 2.79 nm at 61 degrees from normal incidence. The B4C/Pd and B/Mo multilayer mirrors had near-normal incidence (5 degrees) peak reflectances of 11.5% at 8.46 nm and 9.4% at 6.67 nm, respectively, whereas a Y/Mo multilayer mirror had a maximum peak reflectance of 25.6% at 11.30 nm at the same angle. The factors limiting the peak reflectance of these different multilayer mirrors are discussed.

Montcalm, Claude; Kearney, Patrick A.; Slaughter, J. M.; Sullivan, Brian T.; Chaker, M.; Pépin, Henri; Falco, Charles M.

1996-09-01

257

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

SciTech Connect

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

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

2011-04-01

258

Soliton trapping of dispersive waves in photonic crystal fiber with two zero dispersive wavelengths.  

PubMed

Based on the generalized nonlinear Schrödinger equation, we present a numerical study of trapping of dispersive waves by solitons during supercontinuum generation in photonic crystal fibers pumped with femtosecond pulses in the anomalous dispersion region. Numerical simulation results show that the generated supercontinuum is bounded by two branches of dispersive waves, namely blue-shifted dispersive waves (B-DWs) and red-shifted dispersive waves (R-DWs). We find a novel phenomenon that not only B-DWs but also R-DWs can be trapped by solitons across the zero-dispersion wavelength when the group-velocity matching between the soliton and the dispersive wave is satisfied, which may led to the generation of new spectral components via mixing of solitons and dispersive waves. Mixing of solitons with dispersive waves has been shown to play an important role in shaping not only the edge of the supercontinuum, but also its central part around the higher zero-dispersion wavelength. Further, we show that the phenomenon of soliton trapping of dispersive waves in photonic crystal fibers with two zero-dispersion wavelengths has a very close relationship with pumping power and the interval between two zero-dispersion wavelengths. In order to clearly display the evolution of soliton trapping of dispersive waves, the spectrogram of output pulses is observed using cross-correlation frequency-resolved optical gating technique (XFROG). PMID:23669979

Wang, Weibin; Yang, Hua; Tang, Pinghua; Zhao, Chujun; Gao, Jing

2013-05-01

259

Applications of x-ray synchrotron radiation techniques to the study of dispersed electrocatalysts in high area materials  

SciTech Connect

This report discusses work demonstrating that X-Ray Absorption Spectroscopy is a very powerful technique for the study of electrocatalysts. Results for a prototech catalyst, and platinum are presented. (JL)

McBreen, J.

1991-12-31

260

Applications of x-ray synchrotron radiation techniques to the study of dispersed electrocatalysts in high area materials  

SciTech Connect

This report discusses work demonstrating that X-Ray Absorption Spectroscopy is a very powerful technique for the study of electrocatalysts. Results for a prototech catalyst, and platinum are presented. (JL)

McBreen, J.

1991-01-01

261

SO 2Cl 2, SOCl 2: energy dispersive X-ray diffraction, ab initio and molecular dynamics calculation  

Microsoft Academic Search

This work reports a new protocol for achieving microscopic structural information from theoretical (quantum-chemical (QC) and molecular dynamic (MD) calculations) and experimental methods (X-ray diffraction). The Lennard–Jones (L–J) parameters of the force field (FF) fit satisfactorily the X-ray diffraction results of the liquid samples. The study has been carried out on SOCl2 and SO2Cl2 molecular liquids.

S. Meloni; A. Pieretti; L. Bencivenni; V. Rossi Albertini; C. Sadun; R. Caminiti

2001-01-01

262

Invited article: The fast readout low noise camera as a versatile x-ray detector for time resolved dispersive extended x-ray absorption fine structure and diffraction studies of dynamic problems in materials science, chemistry, and catalysis  

NASA Astrophysics Data System (ADS)

Originally conceived and developed at the European Synchrotron Radiation Facility (ESRF) as an ``area'' detector for rapid x-ray imaging studies, the fast readout low noise (FReLoN) detector of the ESRF [J.-C. Labiche, ESRF Newsletter 25, 41 (1996)] has been demonstrated to be a highly versatile and unique detector. Charge coupled device (CCD) cameras at present available on the public market offer either a high dynamic range or a high readout speed. A compromise between signal dynamic range and readout speed is always sought. The parameters of the commercial cameras can sometimes be tuned, in order to better fulfill the needs of specific experiments, but in general these cameras have a poor duty cycle (i.e., the signal integration time is much smaller than the readout time). In order to address scientific problems such as time resolved experiments at the ESRF, a FReLoN camera has been developed by the Instrument Support Group at ESRF. This camera is a low noise CCD camera that combines high dynamic range, high readout speed, accuracy, and improved duty cycle in a single image. In this paper, we show its application in a quasi-one-dimensional sense to dynamic problems in materials science, catalysis, and chemistry that require data acquisition on a time scale of milliseconds or a few tens of milliseconds. It is demonstrated that in this mode the FReLoN can be applied equally to the investigation of rapid changes in long range order (via diffraction) and local order (via energy dispersive extended x-ray absorption fine structure) and in situations of x-ray hardness and flux beyond the capacity of other detectors.

Labiche, Jean-Claude; Mathon, Olivier; Pascarelli, Sakura; Newton, Mark A.; Ferre, Gemma Guilera; Curfs, Caroline; Vaughan, Gavin; Homs, Alejandro; Carreiras, David Fernandez

2007-09-01

263

High-pressure structural transformations of Sn up to 138 GPa: Angle-dispersive synchrotron x-ray diffraction study  

NASA Astrophysics Data System (ADS)

The high-pressure behavior of elemental Sn has been studied by angle-dispersive synchrotron x-ray diffraction up to 138 GPa under quasihydrostatic conditions at room temperature. The data confirm the occurrence of a first-order phase transition at 10.8 GPa between ?-Sn (Sn-II) (I41/amd) and a further body-centered-tetragonal polymorph (?-Sn or Sn-III) (I4/mmm). Above 32 GPa, this phase exhibits a distortion into a new body-centered-orthorhombic (bco) modification (Immm). Beyond 70 GPa, the structure becomes body-centered cubic (bcc) (Im-3m). There is a region of coexistence where the bcc reflections are observed to appear superimposed on the bco pattern above 40 GPa and the two diffraction signatures coexist until 70 GPa. We examined this possible existence of a kinetically hindered first-order phase transition between the two polymorphs by performing density functional theory (DFT) calculations with an emphasis on the potential energy in response to axial (c/a,b/a) distortions at constant volume. The DFT results suggest a slightly different interpretation of the structural transformations. At low pressure, the global minimum energy is always centered around b/a=1, and there is no indication of transformation to a bco structure. However, any small strains in the c/a ratio in the system would provide an orthorhombic distortion of the observed magnitude. Such strains could be induced due to slight deviations from hydrostatic conditions in the experimental study. Concerning the possible bco-bcc phase transitions, the DFT calculations reveal an energy surface with a barrier developed between solutions with different c/a values over the pressure range of interest. Crucially, the calculated barrier heights are low, and they disappear in the region of the observed phase transformation. The DFT results indicate a mechanically softened material that may exhibit localized domain structures in response to even slightly nonhydrostatic stress conditions.

Salamat, Ashkan; Briggs, Richard; Bouvier, Pierre; Petitgirard, Sylvain; Dewaele, Agnès; Cutler, Melissa E.; Corà, Furio; Daisenberger, Dominik; Garbarino, Gaston; McMillan, Paul F.

2013-09-01

264

Energy dispersive X-ray spectrometry study of the protective effects of fluoride varnish and gel on enamel erosion.  

PubMed

Background: Dental erosion is a risk factor for dental health, introduced by today's lifestyle. Topical fluoride applications in the form of varnishes and gel may lead to deposition of fluoride on enamel. Purpose: This in vitro study aimed to evaluate the effect of two fluoride varnishes and one fluoride gel on the dissolution of bovine enamel by acids. Methods: Enamel samples (72) were divided (n = 8): artificial saliva (control-G1), Pepsi Twist® (G2), orange juice (G3), Duraphat® + Pepsi Twist® (G4), Duraphat® + orange juice (G5), Duofluorid® + Pepsi Twist® (G6), Duofluorid® + orange juice (G7), fluoride gel + Pepsi Twist® (G8), and fluoride gel + orange juice (G9). Fluoride gel was applied for 4 min and the varnishes were applied and removed after 6 h. The samples were submitted to six cycles (demineralization: Pepsi Twist® or orange juice, 10 min; remineralization: saliva, 1 h). Samples were analyzed by energy-dispersive X-ray fluorescence (144 line-scanning). Results: The amount of Ca and P decreased significantly in the samples of G2 and G3, and the Ca/P ratio decreased in G3. Mineral gain (Ca) was greater in G9 samples than in G4 > G3 > G5 > G1, and (P) greater in G7 samples than in G9 > G4-6 > G2-3. Conclusions: The protective effect of Duofluorid® was significantly lower than fluoride gel against orange juice. The fluoride varnishes can interfere positively with the dissolution of dental enamel in the presence of acidic beverages. Fluoride gel showed the best protection level to extrinsic erosion with low costs. Microsc. Res. Tech., 2011. © 2010 Wiley-Liss, Inc. PMID:23939672

De Carvalho Filho, Antonio Carlos Belfort; Sanches, Roberto Pizarro; Martin, Airton Abrahão; Do Espírito Santo, Ana Maria; Soares, Luís Eduardo Silva

2010-11-17

265

Energy dispersive x-ray diffraction and reverse Monte Carlo structural study of liquid gallium under pressure  

NASA Astrophysics Data System (ADS)

The structure of liquid gallium has been studied along the melting curve from 0.64 to 5.6 GPa by the energy dispersive x-ray diffraction technique, followed by modeling of the experimental data by the reverse Monte Carlo (RMC) method. The RMC models were constrained by the experimentally obtained equation of states of liquid Ga and in good accordance with experimental data. Analysis of the structure factor S(Q) and the radial distribution function g(r) shows that the anisotropic local structure of liquid Ga deviates from that of a simple hard-sphere-like liquid metal structure. Whereas the third and fourth coordination shell positions and position of the first maximum of S(Q) demonstrate pressure dependencies close to a uniform compression scaled by the (V/V0)1/3 volume relation, the positions of the first (especially) and second coordination spheres have more flat pressure dependencies. At the same time, the first and second coordination numbers increase: The first coordination number starts from 10 to 10.5 and increases by ˜5% in the studied pressure interval. This indicates that liquid gallium contraction is nonuniform, and the local structure changes with increasing pressure. Analysis of the radial distribution function g(r) by a distorted-crystalline model shows that at lower pressures liquid consists of two species similar to the solid Ga I and Ga II structures. The fraction of the Ga I-like part is about 0.2±0.05 at 0.64 GPa, and it gradually decreases under pressure to zero at approximately 7.5±0.5 GPa.

Yagafarov, O. F.; Katayama, Y.; Brazhkin, V. V.; Lyapin, A. G.; Saitoh, H.

2012-11-01

266

The performance of a fast testing system for illicit materials detection based on energy-dispersive X-ray diffraction technique  

Microsoft Academic Search

A prototype setup for detecting illicit materials by energy-dispersive X-ray diffraction (EDXRD) has been developed. The obtained results of NaCl by the equipment suggest that the total measurement system is reliable and can be used to detect different kinds of materials. The tests of TNT, methamphetamine and heroin are also performed on this equipment and the related EDXRD spectra are

Bai Sun; Minqiang Li; Fang Zhang; Yu Zhong; Nansheng Kang; Wei Lu; Jinhuai Liu

2010-01-01

267

Forensic analysis of soil and sediment traces by scanning electron microscopy and energy-dispersive X-ray analysis: An experimental investigation  

Microsoft Academic Search

This paper reports the results of a series of experiments carried out to determine the precision of soil trace comparisons based on elemental peak height ratios determined by energy-dispersive X-ray analysis (EDXRA) in a variable pressure scanning electron microscope (VP-SEM). Experiments were conducted on ‘bulk’ soil aggregates, ground powders prepared from the <150?m soil fractions and on smears of both

Kenneth Pye; Debra Croft

2007-01-01

268

Physical properties and energy dispersive X-ray analysis of Y1- xPrxBa2Cu3O7- delta compounds  

Microsoft Academic Search

The suppression of transition temperature in Y1-xPrxBa2Cu3O7- delta with increasing praseodymium concentration x has given rise to a series of experimental investigations. By making use of the data from energy dispersive X-ray analysis, the ingredients of the materials in the crystal-like layers of the samples can be investigated in a systematic way. This provides sensible and useful clues to understand

T. C. Poon; J. Gao

1995-01-01

269

Non-invasive identification of chemical compounds by energy dispersive X-ray fluorescence spectrometry, combined with chemometric methods of data evaluation  

Microsoft Academic Search

Chemicals from customers’ returns have to be analyzed before they can be reused as raw materials in production. A procedure\\u000a for non-invasive qualitative analysis of compounds in a closed container based on energy dispersive X-ray fluorescence (EDXRF)\\u000a spectrometry is described. EDXRF was chosen as method for non-invasive analysis of chemicals through PE bottle walls without\\u000a opening the bottle. This analysis

A. Henrich; P. Hoffmann; H. M. Ortner; T. Greve; H. Itzel

2000-01-01

270

Magnetic studies and scanning electron microscopy — X-ray energy dispersive spectroscopy analyses of road sediments, soils and vehicle-derived emissions  

Microsoft Academic Search

Human health and environmental problems related to particulate matter emission from vehicles has become a topic of research\\u000a interest in recent years. These airborne particles can not only be directly inhaled, but are also present as suspended and\\u000a deposited particles on paved areas and roadside soils. Here we report on magnetic studies, scanning electron microscopy (SEM),\\u000a X-ray energy dispersive spectroscopy

Marcos A. E. Chaparro; Débora C. Marié; Claudia S. G. Gogorza; Ana Navas; Ana M. Sinito

2010-01-01

271

In situ strain profiling of elastoplastic bending in Ti6Al4V alloy by synchrotron energy dispersive x-ray diffraction  

Microsoft Academic Search

Elastic and plastic strain evolution under four-point bending has been studied by synchrotron energy dispersive x-ray diffraction. Measured strain profiles across the specimen thickness showed an increasing linear elastic strain gradient under increasing four-point bending load up to ~2 kN. The bulk elastic modulus of Ti-6Al-4V was determined as 118 GPa. The onset of plastic deformation was found to set

M. Croft; V. Shukla; E. K. Akdogan; N. Jisrawi; Z. Zhong; R. Sadangi; A. Ignatov; L. Balarinni; K. Horvath; T. Tsakalakos; T Taskalakos

2009-01-01

272

Amalgam tattoo: report of an unusual clinical presentation and the use of energy dispersive X-ray analysis as an aid to diagnosis  

SciTech Connect

An unusual appearing gingival amalgam pigmentation (amalgam tattoo) that completely surrounded the maxillary right first premolar in a 13-year-old boy is presented. Because of the wide distribution and apparent clinical progression of the discoloration, an excisional biopsy was performed. The histopathologic diagnosis of amalgam pigmentation was confirmed in paraffin sections by energy dispersive X-ray microanalysis. Silver, tin, and mercury were detected in the specimen.

McGinnis, J.P. Jr.; Greer, J.L.; Daniels, D.S.

1985-01-01

273

Measuring optical constants from the UV to x-ray wavelengths: how it was (and is) done  

NASA Astrophysics Data System (ADS)

OPtical constants of solids, n the index of refraction, and k the extinction coefficient, are essential for designing components for use in optical instruments, i.e., reflectors, transmitters, etc. In the UV region (4000 - 2000 Å) there are many transmitting glasses and crystals from which ellipsometers can be constructed, consequently extensive use of ellipsometry over the long wavelength part of this region can provide index of refraction values of non-absorbing media accurate to five significant figures. As the wavelength decreases, however, the ellipsometric technique becomes difficult because the components of teh measuring apparatus become absorbing. In the extreme ultraviolet (XUV) from 2000 to 2 A less precise techniques are used. Over most of this region the reflectance vs. angle of incidence (R vs. ?) method is the mainstay. Such n,k measurements can be accurate to three significant figures, seldom more. Furthermore, the method is n,k dependent, i.e., in certain regions of the n,k plane the precision for n or k becomes less than three significant figures while the other value may be more precise; an n,k uncertainy principle. Some ellisometric instrumentation has been developed for the XUV but the spectral range is limited. Other techniques are available for limited spectral ranges; for example, measuring n from R vs. ? curves and measuring k from transmission through thin films, measuring R at near normal incidence over extended wavelength ranges and using the Kramers-Kronig (KK) relations to obtain n,k. Non-optical techniques, such as bombardment of unbacked films with electrons to determine the location and shape of their plasmon oscillation, are useful for limited wavelength ranges.

Hunter, William R.

2004-10-01

274

Quantitative determination on heavy metals in different stages of wine production by Total Reflection X-ray Fluorescence and Energy Dispersive X-ray Fluorescence: Comparison on two vineyards  

NASA Astrophysics Data System (ADS)

The purpose of this study is to determine the elemental content, namely heavy metals, of samples of vine-leaves, grapes must and wine. In order to assess the influence of the vineyard age on the elemental content throughout the several stages of wine production, elemental determinations of trace elements were made on products obtained from two vineyards aged 6 and 14 years from Douro region. The elemental content of vine-leaves and grapes was determined by Energy Dispersive X-Ray Fluorescence (EDXRF), while analysis of the must and wine was performed by Total Reflection X-ray Fluorescence (TXRF). Almost all elements present in wine and must samples did not exceed the recommended values found in literature for wine. Bromine was present in the 6 years old wine in a concentration 1 order of magnitude greater than what is usually detected. The Cu content in vine-leaves from the older vineyard was found to be extremely high probably due to excessive use of Cu-based fungicides to control vine downy mildew. Higher Cu content was also detected in grapes although not so pronounced. Concerning the wine a slightly higher level was detected on the older vineyard, even so not exceeding the recommended value.

Pessanha, Sofia; Carvalho, Maria Luisa; Becker, Maria; von Bohlen, Alex

2010-06-01

275

Trilayer-cubic core-shell structure of PbS/EuS nanocrystals revealed by the combination of the synchrotron small-angle X-ray scattering method and energy-dispersive X-ray spectroscopy.  

PubMed

Multilayer nanostructure analysis has been carried out for core-shell PbS/EuS nanocrystals by the combination of the synchrotron small-angle X-ray scattering (SAXS) method and energy-dispersive X-ray spectroscopy (EDS). SAXS patterns of a dilute hexane solution of the PbS/EuS nanocrystals were measured at a high signal-to-noise ratio by using synchrotron radiation. Initial structure models used for SAXS data analyses were obtained from EDS images of the particle where Eu and O atoms are localized only in the shell part of a quasi-cubic particle and, on the other hand, Pb and S atoms in the core. By simulating the intensity of SAXS using multilayer-cubic models with various core-shell electron density distributions, it was found that the particle structure was explained approximately as a trilayer-cubic model having the PbS core and the EuS/Eu2O3 shell. The diagonal length of the cubic particle was ca. 9.4 nm and the estimated thicknesses of EuS and Eu2O3 layers in the shell were ca. 1.9 and 2.9 nm at maximum, respectively. PMID:24113715

Masunaga, Hiroyasu; Ogawa, Hiroki; Nakashima, Takuya; Kawai, Tsuyoshi; Hikima, Takaaki; Takata, Masaki; Sasaki, Sono

2013-10-11

276

Mineralogy of the clay fraction of soils from the moray cusco archaeological site: a study by energy dispersive X-ray fluorescence, X-ray diffractometry and Mössbauer spectroscopy  

NASA Astrophysics Data System (ADS)

The purpose of this work is to report the advances in the elemental and structural characterization of the clay fraction of soils from the terraces of the Moray Archaeological site, located 38 km north of the city of Cusco, Cusco Region. One sample was collected from each of the twelve terraces of this site and its clay fraction was separated by sedimentation. Previously the pH of the raw samples was measured resulting that all of the samples were from alkaline to strongly alkaline. Energy dispersive X-ray fluorescence (EDXRF) was used for the elemental characterization, and X-ray diffractometry (XRD) and transmission Mössbauer spectroscopy (TMS), using the ? 14.4 keV nuclear resonance transition in 57Fe, were used for the structural characterization of the clays and clay minerals present in each sample. The EDXRF analyses of all the samples show the presence of relatively high concentrations of sulfur in some of the samples and relatively high concentrations of calcium in all of the samples, which may be related to the high alkalinity of the samples. By XRD it is observed the presence of quartz, calcite, gypsum, cronstedtite, 2:1 phyllosilicates, and iron oxides. The mineralogical analysis of Fe by TMS shows that it is present in the form of hematite and occupying Fe2 + and Fe3 + sites in phyllosilicates, cronstedtite, and other minerals not yet identified.

Cerón Loayza, María L.; Bravo Cabrejos, Jorge A.; Mejía Santillán, Mirian E.

2011-11-01

277

Determination of the sequence of intersecting lines from laser toner and seal ink by Fourier transform infrared microspectroscopy and scanning electron microscope / energy dispersive X-ray mapping.  

PubMed

The aim of this study was to verify that the combination of Fourier transform infrared microspectroscopy and scanning electron microscope / energy dispersive X-ray mapping could be applied to line intersection problems. The spectral data of red seal ink, laser toner and their intersections, such as peak location and peak intensity, were described. Relative peak height ratios of different chemical components in intersecting lines were used to distinguish the sequences. Energy dispersive X-ray mapping characteristics of intersecting areas were also detailed. The results show that both the laser toner and the seal ink appear on the surface of intersections, regardless of the sequence. The distribution of the two inks on the surface is influenced not only by the sequence of heterogeneous lines but also by diffusion. Fourier transform infrared microspectroscopy and scanning electron microscope/energy dispersive X-ray mapping are able to explore the chemical components and the corresponding elemental distribution in the intersections. The combination of these two techniques has provided a reliable method for sequencing intersecting lines of red seal ink and laser toner, and more importantly, this method may be a basis for sequencing superimposed lines from other writing instruments. PMID:22583504

Wang, Yuanfeng; Li, Bing

2011-10-29

278

Thermoelectrically cooled semiconductor detectors for non-destructive analysis of works of art by means of energy dispersive X-ray fluorescence  

NASA Astrophysics Data System (ADS)

Thermoelectrically cooled semiconductor detectors, such as Si-PIN, Si-drift, Cd1-xZnxTe and HgI2, coupled to miniaturized low-power X-ray tubes, are well suited in portable systems for energy-dispersive X-ray fluorescence (EDXRF), analysis of archaeological samples. The Si-PIN detector is characterized by a thickness of about 300?m, an area of about 2×3 mm2, an energy resolution of about 200-250eV at 5.9keV and an entrance window of 25-75?m. The Si-drift detector has approximately the same area and thickness, but an energy resolution of 155eV at 5.9keV. The efficiency of these detectors is around 100% from 4 to 10keV, and then decreases versus energy, reaching ~9% at 30keV. Coupled to a miniaturized 10kV, 0.1 mA, Ca-anode or to a miniaturized 30kV, 0.1mA, W-anode X-ray tubes, portable systems can be constructed, which are able to analyse K-lines of elements up to about silver, and L-lines of heavy elements. The Cd1-xZnxTe detector has an area of 4mm2 and a thickness of 3mm. It has an energy resolution of about 300eV at 5.9keV, and an efficiency of 100% over the whole range of X-rays. Finally the HgI2 detector has an efficiency of about 100% in the whole range of X-rays, and an energy resolution of about 200eV at 5.9keV. Coupled to a small 50-60kV, 1mA, W-anode X-ray tube, portable systems can be constructed, for the analysis of practically all elements. These systems were applied to analysis in the field of archaeometry and in all applications for which portable systems are needed or at least useful (for example X-ray transmission measurements, X-ray microtomography and so on). Results of in-field use of these detectors and a comparison among these room temperature detectors in relation to concrete applications are presented. More specifically, concerning EDXRF analysis, ancient gold samples were analysed in Rome, in Mexico City and in Milan, ancient bronzes in Sassari, in Bologna, in Chieti and in Naples, and sulfur (due to pollution) in an old roman fresco in the church of S. Stefano Rotondo (Rome).

Cesareo, R.; Ettore Gigante, G.; Castellano, A.

1999-06-01

279

In-situ wavelength calibration and temperature control for the C-Mod high-resolution x-ray crystal imaging spectrometer  

NASA Astrophysics Data System (ADS)

An x-ray crystal imaging spectrometer with high spectral and spatial resolution is currently being used on Alcator C-Mod to infer time histories of temperature and velocity profiles. An in-situ wavelength calibration using a 1 ?m palladium filter in between the crystal and the detectors of choice is being proposed as a natural wavelength-marker using the transmission changes across the L-II and L-III edges at 3722.9 mA and 3907.1 mA, respectively. Recent results also indicate that the crystal temperature should be kept constant within a fraction of a degree since the thermal expansion of the quartz crystal will change the interplanar (2d) spacing and introduce fictitious velocity measurements of several km/s. A detailed temperature scan indicates a thermal expansion coefficient (?) of 13.5x10-6 /^oC and thus a false Doppler shift of 4.05.?T[^oC] km/s.

Delgado-Aparicio, Luis F.; Podpaly, Y.; Reinke, M. L.; Gao, C.; Rice, J.; Scott, S.; Bitter, M.; Hill, K.; Beiersdorfer, P.; Johnson, D.; Wilson, J. R.

2010-11-01

280

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

281

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

PubMed

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

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

2013-10-01

282

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

EPA Science Inventory

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

283

Energy dispersive x-ray reflectivity applied to the study of thermal stability of self-assembled organic multilayers: Results on phosphonic acids  

NASA Astrophysics Data System (ADS)

The temperature evolution of self-assembled phosphonic acid multilayers was investigated by energy dispersive x-ray reflectivity and angular-resolved reflectivity. Energy dispersive measuremetns allow the precise monitoring of phase transition observed in organic thin film and multilayer systems. The studied multilayers - obtained from dip coating of a solution of octadecylphosphonic acid - presents different bilayer periodicities of 50A? (straight bilayer) and 34A? (tilted bilayer). Energy dispersive and angular-resolved data evidence re-organization of the lamellar ordering of octadecylphosphonic acid multilayers as a function of temperature. The energy dispersive technique presents many advantages over conventional methods such as short acquisition time, possibility to vary external parameters and high flux, making it suitable for light scatterers as polymers and other organic molecules.

Pauli, Muriel De; Pérez, Carlos A.; Malachias, Angelo

2012-05-01

284

Center for X-Ray Optics, 1986  

SciTech Connect

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

Not Available

1987-07-01

285

Controlling X-rays with light  

Microsoft Academic Search

Ultrafast X-ray science is an exciting frontier that promises the visualization of electronic, atomic and molecular dynamics on atomic time and length scales. A largely unexplored area of ultrafast X-ray science is the use of light to control how X-rays interact with matter. To extend control concepts established for long-wavelength probes to the X-ray regime, the optical control field must

T. E. Glover; Marcus Hertlein; Steve Southworth; Tom Allison; Jeroen van Tilborg; Elliot Kanter; B. Krässig; H. R. Varma; Bruce Rude; Robin Santra; Ali Belkacem; Linda Young

2010-01-01

286

Direct Observation of Microscopic Inhomogeneities with Energy-Dispersive Diffraction of Synchrotron-Produced X-rays  

Microsoft Academic Search

Evidence of structural inhomogeneities in two high-transition-temperature superconductors, YBa_2Cu_3O7-delta and Nd2-xCe_xCuO4-y, is presented. When samples were illuminated by highly collimated x-rays produced on a synchrotron wiggler, small changes in the lattice were detected over a spatial scale of 10 micrometers. These changes are interpreted as evidence of variations in the oxygen content in one case and in the cerium content

E. F. Skelton; A. R. Drews; M. S. Osofsky; S. B. Qadri; J. Z. Hu; T. A. Vanderah; J. L. Peng; R. L. Greene

1994-01-01

287

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

Microsoft Academic Search

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

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

2010-01-01

288

An X-ray absorption spectroscopy study of the inversion degree in zinc ferrite nanocrystals dispersed on a highly porous silica aerogel matrix.  

PubMed

The structural properties of zinc ferrite nanoparticles with spinel structure dispersed in a highly porous SiO(2) aerogel matrix were compared with a bulk zinc ferrite sample. In particular, the details of the cation distribution between the octahedral (B) and tetrahedral (A) sites of the spinel structure were determined using X-ray absorption spectroscopy. The analysis of both the X-ray absorption near edge structure and the extended X-ray absorption fine structure indicates that the degree of inversion of the zinc ferrite spinel structures varies with particle size. In particular, in the bulk microcrystalline sample, Zn(2+) ions are at the tetrahedral sites and trivalent Fe(3+) ions occupy octahedral sites (normal spinel). When particle size decreases, Zn(2+) ions are transferred to octahedral sites and the degree of inversion is found to increase as the nanoparticle size decreases. This is the first time that a variation of the degree of inversion with particle size is observed in ferrite nanoparticles grown within an aerogel matrix. PMID:23406136

Carta, D; Marras, C; Loche, D; Mountjoy, G; Ahmed, S I; Corrias, A

2013-02-01

289

An X-ray absorption spectroscopy study of the inversion degree in zinc ferrite nanocrystals dispersed on a highly porous silica aerogel matrix  

NASA Astrophysics Data System (ADS)

The structural properties of zinc ferrite nanoparticles with spinel structure dispersed in a highly porous SiO2 aerogel matrix were compared with a bulk zinc ferrite sample. In particular, the details of the cation distribution between the octahedral (B) and tetrahedral (A) sites of the spinel structure were determined using X-ray absorption spectroscopy. The analysis of both the X-ray absorption near edge structure and the extended X-ray absorption fine structure indicates that the degree of inversion of the zinc ferrite spinel structures varies with particle size. In particular, in the bulk microcrystalline sample, Zn2+ ions are at the tetrahedral sites and trivalent Fe3+ ions occupy octahedral sites (normal spinel). When particle size decreases, Zn2+ ions are transferred to octahedral sites and the degree of inversion is found to increase as the nanoparticle size decreases. This is the first time that a variation of the degree of inversion with particle size is observed in ferrite nanoparticles grown within an aerogel matrix.

Carta, D.; Marras, C.; Loche, D.; Mountjoy, G.; Ahmed, S. I.; Corrias, A.

2013-02-01

290

Misidentification of Major Constituents by Automatic Qualitative Energy Dispersive X-ray Microanalysis: A Problem that Threatens the Credibility of the Analytical Community  

NASA Astrophysics Data System (ADS)

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

Newbury*, Dale E.

2005-12-01

291

Effect of silica capping on the oxidation of Fe3O4 nanoparticles in dispersion revealed by x-ray absorption spectroscopy  

NASA Astrophysics Data System (ADS)

Fe3O4 nanoparticles have been investigated as they are biocompatible and their surface can be functionalized. We synthesized iron oxide nanoparticles using a water-in-oil microemulsion method. Bare and silica-coated iron oxide nanoparticles of a core size of 6 nm dispersed in ethanol have been investigated by means of x-ray absorption spectroscopy (XAS). Due to a dedicated experimental setup the particles can be measured directly in dispersion. XAS allows us to disentangle the contributions of the Fe2+ and Fe3+ ions and therefore to estimate the amount of Fe3O4 in the particles. In case of the silica coated particles a high amount of magnetite was obtained. In contrast, the bare nanoparticles showed indications of a further oxidation into ?-Fe2O3 even in dispersion.

Warland, A.; Antoniak, C.; Darbandi, M.; Weis, C.; Landers, J.; Keune, W.; Wende, H.

2012-06-01

292

Multi-frame acquisition scheme for efficient energy-dispersive X-ray magnetic circular dichroism in pulsed high magnetic fields at the Fe K-edge  

PubMed Central

Using a fast silicon strip detector, a multi-frame acquisition scheme was implemented to perform energy-dispersive X-ray magnetic circular dichroism at the iron K-edge in pulsed high magnetic fields. The acquisition scheme makes use of the entire field pulse. The quality of the signal obtained from samples of ferrimagnetic erbium iron garnet allows for quantitative evaluation of the signal amplitude. Below the compensation point, two successive field-induced phase transitions and the reversal of the net magnetization of the iron sublattices in the intermediate phase were observed.

Strohm, Cornelius; Perrin, Florian; Dominguez, Marie-Christine; Headspith, Jon; van der Linden, Peter; Mathon, Olivier

2011-01-01

293

Rapid simultaneous multi-element determination of soils and environmental samples with polarizing energy dispersive X-ray fluorescence (EDXRF) spectrometry using pressed powder pellets  

Microsoft Academic Search

A rapid simultaneous multi-element analysis method for soils and environmental samples has been established using polarizing energy dispersive X-ray fluorescence (EDXRF) spectrometry. The pressed powder pellet technique was adopted because it is simple and requires no specialized skills for sample preparation. The analytes examined were: Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, MnO, Fe2O3, V, Cr, Co, Ni, Cu,

Hisaya Matsunami; Kenji Matsuda; Shin-ichi Yamasaki; Kazuhiko Kimura; Yasumasa Ogawa; Yoshinori Miura; Isao Yamaji; Noriyoshi Tsuchiya

2010-01-01

294

Effect of hydration on the structure of oriented lipid membranes investigated by in situ time-resolved energy dispersive x-ray diffraction  

SciTech Connect

In situ time-resolved energy dispersive x-ray diffraction (EDXD) was applied to investigate the effect of hydration on the structure of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)-oriented membranes. The measurements allowed a very high density time sampling of the evolution of the structural properties of the DOTAP bilayer such as the lamellar d-spacing, the membrane thickness, and the size of the interbilayer water region. Time-resolved EDXD has been found to provide important information on the role played by free water molecules on the structure and fluidity of lipid bilayer.

Caminiti, Ruggero; Caracciolo, Giulio; Pisani, Michela [Universita di Roma 'La Sapienza', Dipartimento di Chimica and INFM, Rome (Italy); Universita Politecnica delle Marche, Dipartimento di Scienze dei Materiali e della Terra, Ancona (Italy)

2005-06-20

295

In situ energy dispersive x-ray reflectometry to investigate the (RuPc){sub 2}/NO{sub x} interaction process evidenced by ex situ measurements  

SciTech Connect

A systematic energy dispersive x-ray reflectometry study of different ruthenium phthalocyanine (RuPc){sub 2} thin films was performed in order to investigate their reactivity with the oxidizing NO{sub x} gas. A preliminary ex situ analysis, consisting of the comparison between the morphological parameters of different films (before and after the exposure to the gas), was performed. It suggests that a reaction involving two different mechanisms takes place. The following in situ (while fluxing the gas) reflectometry analysis confirms this hypothesis, and clarifies the temporal evolution, also revealing that the first mechanism is limited to the film surface, while the second is a bulk diffusion process.

Generosi, Amanda; Paci, Barbara; Rossi Albertini, Valerio; Perfetti, Paolo; Paoletti, Anna M.; Pennesi, Gianna; Rossi, Gentilina; Caminiti, Ruggero [Istituto di Struttura della Materia-Area di Ricerca di Tor Vergata, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Istituto di Struttura della Materia-Area di Ricerca di Montelibretti, Via Salaria Km. 29.5, Casclla Portale 10 Monterotondo Stazione, I-00016 Rome (Italy); Dipartimento di Chimica, Universita ''La Sapienza'' di Roma e sezione INFM, Piazale Aldo Moro 5, 00185 Rome (Italy)

2006-02-15

296

Spectral Interferometry-Based Chromatic Dispersion Measurement of Fibre Including the Zero-Dispersion Wavelength  

NASA Astrophysics Data System (ADS)

We report on a simple spectral interferometric technique for chromatic dispersion measurement of a short length optical fibre including the zero-dispersion wavelength. The method utilizes a supercontinuum source, a dispersion balanced Mach-Zehnder interferometer and a fibre under test of known length inserted in one of the interferometer arms and the other arm with adjustable path length. The method is based on resolving one spectral interferogram (spectral fringes) by a low-resolution NIR spectrometer. The fringe order versus the precise wavelength position of the interference extreme in the recorded spectral signal is fitted to the approximate function from which the chromatic dispersion is obtained. We verify the applicability of the method by measuring the chromatic dispersion of two polarization modes in a birefringent holey fibre. The measurement results are compared with those obtained by a broad spectral range (500-1600 nm) measurement method, and good agreement is confirmed.

Hlubina, P.; Kadulová, M.; Ciprian, D.

2012-05-01

297

X-Ray Microdiffraction at Megabar Pressures  

NASA Astrophysics Data System (ADS)

High-pressure x-ray diffraction (XRD) provides unique, important sources of structural information of minerals in the Earth's deep interior, but encounters major limitations. The restriction to forward diffraction geometry (2? less than 90° ) severely limits the accuracy. With the 50-5 ? m size x-ray beam typically used to probe samples at 30-200 GPa, the number of crystals covered by the x-ray beam is often too few for good polycrystalline XRD, but too numerous for single-crystal XRD. Single-crystal XRD method with monochromatic x-ray source and 2-d detector works satisfactorily for crystal size larger than 20 ? m, but when the crystal is significantly less than 5 ? m, the sample signals are often overwhelmed by the background. Energy dispersive XRD with polychromatic x-radiation has been used successfully to determine unit-cell parameters of smaller single crystals, but the intensity information is unusable for structural refinement because this method requires rotation of the small crystal relative to the small x-ray beam. Recent integration of panoramic diamond anvil cell1 (PDAC) with synchrotron x-ray microdiffraction2 (XRMD) method has finally overcome these limitations and can potentially revolutionize the high-pressure XRD field. This XRMD method focuses polychromatic x-radiation to submicrometer size to resolve very small single crystals, and collects Laue spots with a 2-d CCD detector. The PDAC allows complete forward, 90° , and back scatterings, while the background signal is minimized by directing the incident x-ray beam through single-crystal diamonds (i.e., avoiding the beryllium seats and gasket). The incident beam can be changed to monochromatic, tuned through the full energy (wavelength) range, and focused to the identical submicrometer spot for d-spacing determination of each Laue spot. All polychromatic Laue spots are collected simultaneously from the same x-ray sampled volume, thus reliable for structure determination. The development provide long-sought solutions to important technical and scientific issues, including the fundamental changes of silicates, oxides, ices, and condensed gases that are the main components of deep planetary interiors. 1 H. K. Mao, J. Xu, V. V. Struzhkin, et al., Science 292, 914 (2001). 2 N. Tamura, R. S. Celestre, A. A. MacDowell, et al., Rev. Sci. Instrum. 73, 1369 (2002).

Mao, H.

2003-12-01

298

[Research on the application of improved M-P neural network to the determination of lead and zinc ore element contents by energy disperse X-ray fluorescence analysis].  

PubMed

Because of different constraints (such as different kinds of measurable elements, characteristic X-ray energy, changes in matrix composition, etc.), usually it's not easy to get accurate information of elements, resulting in mistakes in later data analysis of energy disperse X-ray fluorescence measurement. The method is based on McCulloch-Pitts neural network (M-P neural network), according to matrix effect, to establish a new neural network model for quantitative forecasting of Zn by taking the data of X-ray fluorescence measurements of Cu, Fe, Pb, etc in lead-zinc mine in western Tianshan as the training sample. The relative error between predicted value and measured value is less than 5%. This method can be more accurate and rapid for X-ray fluorescence; it provides a new approach to correcting information of X-ray fluorescence. PMID:22827102

Li, Fei; Ge, Liang-quan; Zhang, Qing-xian; Gu, Yi; Wan, Zhi-xiong; Li, Wang-yan

2012-05-01

299

Structural characterization of the phospholipid stabilizer layer at the solid-liquid interface of dispersed triglyceride nanocrystals with small-angle x-ray and neutron scattering  

NASA Astrophysics Data System (ADS)

Dispersions of crystalline nanoparticles with at least one sufficiently large unit cell dimension can give rise to Bragg reflections in the small-angle scattering range. If the nanocrystals possess only a small number of unit cells along these particular crystallographic directions, the corresponding Bragg reflections will be broadened. In a previous study of phospholipid stabilized dispersions of ?-tripalmitin platelets [Unruh, J. Appl. Crystallogr.JACGAR0021-889810.1107/S0021889807044378 40, 1008 (2007)], the x-ray powder pattern simulation analysis (XPPSA) was developed. The XPPSA method facilitates the interpretation of the rather complicated small-angle x-ray scattering (SAXS) curves of such dispersions of nanocrystals. The XPPSA method yields the distribution function of the platelet thicknesses and facilitates a structural characterization of the phospholipid stabilizer layer at the solid-liquid interface between the nanocrystals and the dispersion medium from the shape of the broadened 001 Bragg reflection. In this contribution an improved and extended version of the XPPSA method is presented. The SAXS and small-angle neutron scattering patterns of dilute phospholipid stabilized tripalmitin dispersions can be reproduced on the basis of a consistent simulation model for the particles and their phospholipid stabilizer layer on an absolute scale. The results indicate a surprisingly flat arrangement of the phospholipid molecules in the stabilizer layer with a total thickness of only 12 Å. The stabilizer layer can be modeled by an inner shell for the fatty acid chains and an outer shell including the head groups and additional water. The experiments support a dense packing of the phospholipid molecules on the nanocrystal surfaces rather than isolated phospholipid domains.

Schmiele, Martin; Schindler, Torben; Unruh, Tobias; Busch, Sebastian; Morhenn, Humphrey; Westermann, Martin; Steiniger, Frank; Radulescu, Aurel; Lindner, Peter; Schweins, Ralf; Boesecke, Peter

2013-06-01

300

Structural characterization of the phospholipid stabilizer layer at the solid-liquid interface of dispersed triglyceride nanocrystals with small-angle x-ray and neutron scattering.  

PubMed

Dispersions of crystalline nanoparticles with at least one sufficiently large unit cell dimension can give rise to Bragg reflections in the small-angle scattering range. If the nanocrystals possess only a small number of unit cells along these particular crystallographic directions, the corresponding Bragg reflections will be broadened. In a previous study of phospholipid stabilized dispersions of ?-tripalmitin platelets [Unruh, J. Appl. Crystallogr. 40, 1008 (2007)], the x-ray powder pattern simulation analysis (XPPSA) was developed. The XPPSA method facilitates the interpretation of the rather complicated small-angle x-ray scattering (SAXS) curves of such dispersions of nanocrystals. The XPPSA method yields the distribution function of the platelet thicknesses and facilitates a structural characterization of the phospholipid stabilizer layer at the solid-liquid interface between the nanocrystals and the dispersion medium from the shape of the broadened 001 Bragg reflection. In this contribution an improved and extended version of the XPPSA method is presented. The SAXS and small-angle neutron scattering patterns of dilute phospholipid stabilized tripalmitin dispersions can be reproduced on the basis of a consistent simulation model for the particles and their phospholipid stabilizer layer on an absolute scale. The results indicate a surprisingly flat arrangement of the phospholipid molecules in the stabilizer layer with a total thickness of only 12 Å. The stabilizer layer can be modeled by an inner shell for the fatty acid chains and an outer shell including the head groups and additional water. The experiments support a dense packing of the phospholipid molecules on the nanocrystal surfaces rather than isolated phospholipid domains. PMID:23848684

Schmiele, Martin; Schindler, Torben; Unruh, Tobias; Busch, Sebastian; Morhenn, Humphrey; Westermann, Martin; Steiniger, Frank; Radulescu, Aurel; Lindner, Peter; Schweins, Ralf; Boesecke, Peter

2013-06-20

301

High pressure and high temperature investigations on intermetallic compounds using energy-dispersive X-ray powder diffraction  

Microsoft Academic Search

The intermetallic compounds Mg2Si, MoSi2, WSi2, CrSi2, NbSi2, Ti5Si3, TiSi2, ZrSi2 and Al3Nb were investigated in a pressure range up to 70 kbar and a temperature range up to 1500°C in order to determine previously unknown elastic constants and possible phase transformations. The experiments were carried out using the multi-anvil-X-ray apparatus MAX-80 and synchrotron radiation at HASYLAB. A complete phase

T. Peun; J. Lauterjung; E. Hinze

1995-01-01

302

Elemental analysis of human amniotic fluid and placenta by total-reflection X-ray fluorescence and energy-dispersive X-ray fluorescence: child weight and maternal age dependence  

NASA Astrophysics Data System (ADS)

This work is an attempt to evaluate the possible influence of the mother's age in trace element concentrations in human amniotic fluid and placenta and whether these concentrations are correlated to the weight of the newborn infants. Total-reflection X-ray fluorescence (TXRF) was used to analyze 16 amniotic fluid samples, and the placenta samples were analyzed by energy dispersive X-ray fluorescence (EDXRF). The whole samples were collected during delivery from healthy mothers and healthy infants and full-term pregnancies. According to the age of the mother, three different groups were considered: 20-25, 25-30 and 30-40 years old. Only two mothers were aged more than 35 years. The weight of the infants ranged from 2.56 to 4.05 kg and three groups were also considered: 2.5-3, 3-3.5 and 3.5-4 kg. The organic matrix of the amniotic fluid samples was removed by treatment with HNO 3 followed by oxygen plasma ashing. Yttrium was used as the internal standard for TXRF analysis. Placenta samples were lyophilized and analyzed by EDXRF without any chemical treatment. Very low levels of Ni and Sr were found in the amniotic fluid samples, and were independent of the age of the mother and weight of the child. Cr, Mn, Se and Pb were at the level of the detection limit. Zn, considered one of the key elements in neonatal health, was not significantly different in the samples analyzed; however, it was weakly related to birth weigh. The concentrations obtained ranged from 0.11 to 0.92 mg/l and 30 to 65 ?g/g in amniotic fluid and placenta, respectively. The only two elements which seemed to be significantly correlated with mother's age and newborn weight were Ca and Fe for both types of sample: Ca levels were increased in heavier children and older mothers; however, Fe increased with increasing maternal age, but decreased for heavier babies. The same conclusions were obtained for placenta and amniotic fluid samples. Cu is closely associated with Fe in its function in the organism and has a similar behavior to this element, but not as pronounced.

Carvalho, M. L.; Custódio, P. J.; Reus, U.; Prange, A.

2001-11-01

303

Synchrotron Radiation and Energy Dispersive X-Ray Fluorescence Applications on Elemental Distribution in Human Hair and Bones  

SciTech Connect

This work is an application of synchrotron microprobe X- Ray fluorescence in order to study elemental distribution along human hair samples of contemporary citizens. Furthermore, X-Ray fluorescence spectrometry is also used to analyse human bones of different historical periods: Neolithic and contemporary subjects. The elemental content in the bones allowed us to conclude about environmental contamination, dietary habits and health status influence in the corresponding citizens. All samples were collected post-mortem. Quantitative analysis was performed for Mn, Fe, Co, Ni, Cu, Zn, Br, Rb, Sr and Pb. Mn and Fe concentration were much higher in bones from pre-historic periods. On the contrary, Pb bone concentrations of contemporary subjects are much higher than in pre-historical ones, reaching 100 {mu}g g-1, in some cases. Very low concentrations for Co, Ni, Br and Rb were found in all the analysed samples. Cu concentrations, allows to distinguish Chalcolithic bones from the Neolithic ones. The distribution of trace elements along human hair was studied for Pb and the obtained pattern was consistent with the theoretical model, based on the diffusion of this element from the root and along the hair. Therefore, the higher concentrations in hair for Pb of contemporary individuals were also observed in the bones of citizens of the same sampling sites. All samples were analysed directly without any chemical treatment.

Carvalho, M.L.; Marques, A.F.; Brito, J. [Centro de Fisica Atomica, Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal)

2003-01-24

304

Skull x-ray  

MedlinePLUS

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

305

Direct analysis of plutonium metal for gallium, iron, and nickel by energy dispersive x-ray spectrometry  

SciTech Connect

An x-ray secondary target method for routine determination of gallium, iron, and nickel in plutonium metal is described that has significant advantages over wet chemical analysis. Coupons requiring minimal preparation for analysis are produced as a breakaway tab on the plutonium ingot. All three elements are determined on the same coupon. Gallium is determined using an arsenic secondary target followed by iron and nickel using a zinc target. The analysis times are 5 minutes for gallium and 15 minutes for the combined iron and nickel. The method of analysis was evaluated in the range of from 0.5 to 1.5% gallium. Iron was investigated over the range of 67 to 3000 ppM and nickel from 64 to 110 ppM.

Bramlet, H.L.; Doyle, J.H.

1981-01-01

306

2-Dimensional beamsteering using dispersive deflectors and wavelength tuning.  

PubMed

We introduce a 2D beamscanner which is controlled by wavelength tuning. Two passive dispersive devices are aligned orthogonally to deflect the optical beam in two dimensions. We provide a proof of principle demonstration by combining an arrayed waveguide grating with a free space optical grating and using various input sources to characterize the beamscanner. This achieved a discrete 10.3 degrees by 11 degrees output field of view with attainable angles existing on an 8 by 6 grid of directions. The entire range was reached by scanning over a 40 nm wavelength range. We also analyze an improved system combining a virtually imaged phased array with a diffraction grating. This device is much more compact and produces a continuous output scan in one direction while being discrete in the other. PMID:18794998

Chan, Trevor; Myslivets, Evgeny; Ford, Joseph E

2008-09-15

307

Frequency Filter of Seed X-ray by Use of X-ray Laser Medium: Toward the Generation of the Temporally Coherent X-ray Laser  

Microsoft Academic Search

We evaluate the characteristics of a higher-order harmonics light as a seed X-ray amplified through a laser-produced X-ray amplifier. The narrow spectral bandwidth of the X-ray amplifier works as the frequency filter of the seed X-ray, resulting in that only the temporally coherent X-ray is amplified. Experimental investigation using the 29th-order harmonic light of the Ti:sapphire laser at a wavelength

Noboru Hasegawa; Tetsuya Kawachi; Maki Kishimoto; Kouta Sukegawa; Momoko Tanaka; Tai Renzhong; Yoshihiro Ochi; Masaharu Nishikino; Keisuke Nagashima; Yoshiaki Kato

2009-01-01

308

X-ray lithography using holographic images  

DOEpatents

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

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

1995-01-01

309

X-ray fluorescence analysis major elements in silicate minerals  

SciTech Connect

An automated wavelength-dispersive x-ray fluorescence spectrometer is operational for analysis of major elements in rocks and minerals. Procedures for trace-element analysis are being developed. Sample preparation methods and analytical techniques are similar to those commonly used elsewhere, but data reduction is conducted by the Fundamental Parameters program developed by Criss. Unlike empirically derived calibration curves, this data reduction method considers x-ray absorption and secondary fluorescence, which vary with differences in sample composition. X-ray intensities for each element from several standards are averaged to develop a theoretical standard for comparison with samples of unknown composition. Accurate data for samples with wide compositional ranges result from these data reduction and standardization techniques.

Hagan, R.C.

1982-09-01

310

Non-invasive identification of chemical compounds by energy dispersive X-ray fluorescence spectrometry, combined with chemometric methods of data evaluation.  

PubMed

Chemicals from customers' returns have to be analyzed before they can be reused as raw materials in production. A procedure for non-invasive qualitative analysis of compounds in a closed container based on energy dispersive X-ray fluorescence (EDXRF) spectrometry is described. EDXRF was chosen as method for noninvasive analysis of chemicals through PE bottle walls without opening the bottle. This analysis aims for a quick proof of correspondence between the declaration of a reagent on the label of the bottle and its content. This analytical result cannot be achieved by a mere evaluation of characteristic element lines in EDXRF-spectra in combination with the method of matrix correction or the method of mean atomic number. These methods take into account only a small part of the total information available in an X-ray spectrum. It is shown here that valuable additional information is extractable from the spectral ranges of the Compton-scattering and Rayleigh-scattering areas by the use of methods of multivariate data analysis, especially by principle component analysis (PCA). Regularized discriminant analysis (RDA) was employed to establish a classification scheme for unknown samples. PMID:11220570

Henrich, A; Hoffmann, P; Ortner, H M; Greve, T; Itzel, H

311

The classification of secondary colorectal liver cancer in human biopsy samples using angular dispersive x-ray diffraction and multivariate analysis  

NASA Astrophysics Data System (ADS)

The motivation behind this study is to assess whether angular dispersive x-ray diffraction (ADXRD) data, processed using multivariate analysis techniques, can be used for classifying secondary colorectal liver cancer tissue and normal surrounding liver tissue in human liver biopsy samples. The ADXRD profiles from a total of 60 samples of normal liver tissue and colorectal liver metastases were measured using a synchrotron radiation source. The data were analysed for 56 samples using nonlinear peak-fitting software. Four peaks were fitted to all of the ADXRD profiles, and the amplitude, area, amplitude and area ratios for three of the four peaks were calculated and used for the statistical and multivariate analysis. The statistical analysis showed that there are significant differences between all the peak-fitting parameters and ratios between the normal and the diseased tissue groups. The technique of soft independent modelling of class analogy (SIMCA) was used to classify normal liver tissue and colorectal liver metastases resulting in 67% of the normal tissue samples and 60% of the secondary colorectal liver tissue samples being classified correctly. This study has shown that the ADXRD data of normal and secondary colorectal liver cancer are statistically different and x-ray diffraction data analysed using multivariate analysis have the potential to be used as a method of tissue classification.

Theodorakou, Chrysoula; Farquharson, Michael J.

2009-08-01

312

Performance of a gaseous detector based energy dispersive X-ray fluorescence imaging system: Analysis of human teeth treated with dental amalgam  

NASA Astrophysics Data System (ADS)

Energy dispersive X-ray fluorescence (EDXRF) imaging systems are of great interest in many applications of different areas, once they allow us to get images of the spatial elemental distribution in the samples. The detector system used in this study is based on a micro patterned gas detector, named Micro-Hole and Strip Plate. The full field of view system, with an active area of 28 × 28 mm2 presents some important features for EDXRF imaging applications, such as a position resolution below 125 ?m, an intrinsic energy resolution of about 14% full width at half maximum for 5.9 keV X-rays, and a counting rate capability of 0.5 MHz. In this work, analysis of human teeth treated by dental amalgam was performed by using the EDXRF imaging system mentioned above. The goal of the analysis is to evaluate the system capabilities in the biomedical field by measuring the drift of the major constituents of a dental amalgam, Zn and Hg, throughout the tooth structures. The elemental distribution pattern of these elements obtained during the analysis suggests diffusion of these elements from the amalgam to teeth tissues.

Silva, A. L. M.; Figueroa, R.; Jaramillo, A.; Carvalho, M. L.; Veloso, J. F. C. A.

2013-08-01

313

Chain-length dependent growth dynamics of n-alkanes on silica investigated by energy-dispersive x-ray reflectivity in situ and in real-time  

SciTech Connect

We compare the growth dynamics of the three n-alkanes C{sub 36}H{sub 74}, C{sub 40}H{sub 82}, and C{sub 44}H{sub 90} on SiO{sub 2} using real-time and in situ energy-dispersive x-ray reflectivity. All molecules investigated align in an upright-standing orientation on the substrate and exhibit a transition from layer-by-layer growth to island growth after about 4 monolayers under the conditions employed. Simultaneous fits of the reflected intensity at five distinct points in reciprocal space show that films formed by longer n-alkanes roughen faster during growth. This behavior can be explained by a chain-length dependent height of the Ehrlich-Schwoebel barrier. Further x-ray diffraction measurements after growth indicate that films consisting of longer n-alkanes also incorporate more lying-down molecules in the top region. While the results reveal behavior typical for chain-like molecules, the findings can also be useful for the optimization of organic field effect transistors where smooth interlayers of n-alkanes without coexistence of two or more molecular orientations are required.

Weber, C.; Rukat, T.; Schaefer, P.; Kowarik, S. [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstr. 15, 12489 Berlin (Germany); Frank, C.; Schreiber, F. [Institut fuer Angewandte Physik, Universitaet Tuebingen, Auf der Morgenstelle 10, 72076 Tuebingen (Germany); Bommel, S. [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstr. 15, 12489 Berlin (Germany); Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg (Germany); Leitenberger, W. [Institut fuer Physik, Universitaet Potsdam, Karl-Liebknecht-Strasse 24/25,14476 Potsdam-Golm (Germany)

2012-05-28

314

A standards-based method for compositional analysis by energy dispersive X-ray spectrometry using multivariate statistical analysis: application to multicomponent alloys.  

PubMed

Given an unknown multicomponent alloy, and a set of standard compounds or alloys of known composition, can one improve upon popular standards-based methods for energy dispersive X-ray (EDX) spectrometry to quantify the elemental composition of the unknown specimen? A method is presented here for determining elemental composition of alloys using transmission electron microscopy-based EDX with appropriate standards. The method begins with a discrete set of related reference standards of known composition, applies multivariate statistical analysis to those spectra, and evaluates the compositions with a linear matrix algebra method to relate the spectra to elemental composition. By using associated standards, only limited assumptions about the physical origins of the EDX spectra are needed. Spectral absorption corrections can be performed by providing an estimate of the foil thickness of one or more reference standards. The technique was applied to III-V multicomponent alloy thin films: composition and foil thickness were determined for various III-V alloys. The results were then validated by comparing with X-ray diffraction and photoluminescence analysis, demonstrating accuracy of approximately 1% in atomic fraction. PMID:23298470

Rathi, Monika; Ahrenkiel, S P; Carapella, J J; Wanlass, M W

2013-01-08

315

X-ray laser developments at PHELIX  

NASA Astrophysics Data System (ADS)

Development of x-ray lasers using the PHELIX laser at the GSI Helmholtz center for heavy-ion research [1] is targeting a number of applications of novel x-ray sources in combination with energetic heavy-ion beams. This includes Thomson scattering diagnostics of heavy-ion driven plasmas, x-ray opacity measurements, and x-ray laser spectroscopy of highly-charged ions. Developments centered on the application of a novel double-pulse GRIP-like pumping scheme, DGRIP, where nonnormal incidence geometry is used for both the pre- and the main pulse for transient pumped Ni-like x-ray lasers [2,3]. This scheme was used at lower energy levels to pump soft x-ray lasers in the 50 - 100 eV regime as well as for pulse energies above 100 J for the pumping of shorter wavelength soft x-ray lasers [4].

Zielbauer, B.; Kuehl, T.; Aurand, B.; Bagnoud, V.; Ecker, B.; Eisenbarth, U.; Hochhaus, D. C.; Neumayer, P.; Zimmer, D.; Cassou, K.; Daboussi, S.; Guilbaud, O.; Habib, J.; Kazamias, S.; Ros, D.; Seres, J.; Spielmann, C.

316

Residual stresses and tetragonal phase fraction characterisation of corrosion tested Zircaloy-4 using energy dispersive synchrotron X-ray diffraction  

NASA Astrophysics Data System (ADS)

To improve the understanding of the oxidation mechanism in zirconium alloys for fuel clad applications, detailed residual stress and phase fraction analysis was carried out for the oxides formed on Zircaloy-4 after autoclave exposure at 360 °C for various times by means of synchrotron X-ray diffraction. In a post-transition sample (220 days), significant stress variation through the oxide thickness was found for the monoclinic phase in individual oxide layers, with maximum in-plane compressive stresses located towards the metal-oxide interface and a discontinuity in the residual stress profile. The depth of this discontinuity matched well with the depth at which electron microscopy analysis showed an interface between two distinct oxide layers. Analysis of the tetragonal phase with exposure time demonstrated changes of the total volume of tetragonal phase before and during transition. These observations are put into the context of residual stress evolution presented previously, to provide further insight into the importance of phase transformations and residual stresses in determining the corrosion kinetics of Zr alloys.

Polatidis, E.; Frankel, P.; Wei, J.; Klaus, M.; Comstock, R. J.; Ambard, A.; Lyon, S.; Cottis, R. A.; Preuss, M.

2013-01-01

317

Nanometer-scale, quantitative composition mappings of InGaN layers from a combination of scanning transmission electron microscopy and energy dispersive x-ray spectroscopy.  

PubMed

Using elastic scattering theory we show that a small set of energy dispersive x-ray spectroscopy (EDX) measurements is sufficient to experimentally evaluate the scattering function of electrons in high-angle annular dark field scanning transmission microscopy (HAADF-STEM). We then demonstrate how to use this function to transform qualitative HAADF-STEM images of InGaN layers into precise, quantitative chemical maps of the indium composition. The maps obtained in this way combine the resolution of HAADF-STEM and the chemical precision of EDX. We illustrate the potential of such chemical maps by using them to investigate nanometer-scale fluctuations in the indium composition and their impact on the growth of epitaxial InGaN layers. PMID:23089619

Pantzas, K; Patriarche, G; Troadec, D; Gautier, S; Moudakir, T; Suresh, S; Largeau, L; Mauguin, O; Voss, P L; Ougazzaden, A

2012-10-22

318

Atomic-Resolution X-ray Energy-Dispersive Spectroscopy Chemical Mapping of Substitutional Dy Atoms in a High-Coercivity Neodymium Magnet  

NASA Astrophysics Data System (ADS)

We have investigated local element distributions in a Dy-doped Nd2Fe14B hot-deformed magnet by atomic-column resolution chemical mapping using an X-ray energy-dispersive spectrometer (XEDS) attached to an aberration-corrected scanning transmission electron microscope (Cs-corrected STEM). The positions of the Nd and Dy atomic columns were visualized in the XEDS maps. The substitution of Dy was limited to a surface layer 2--3 unit cells thick in the Nd2Fe14B grains, and the Dy atoms preferentially occupied the 4f-Nd sites of Nd2Fe14B. These results provide further insights into the principal mechanism governing the coercivity enhancement due to Dy doping.

Itakura, Masaru; Watanabe, Natsuki; Nishida, Minoru; Daio, Takeshi; Matsumura, Syo

2013-05-01

319

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

SciTech Connect

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

Cunsolo, Alessandro (BNL)

2012-10-23

320

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

NASA Astrophysics Data System (ADS)

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

Cunsolo, Alessandro

2012-09-01

321

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

PubMed

The high frequency transport properties of glycerol are derived from inelastic x-ray scattering spectra measured at different pressures and compared with ultrasound absorption data. As a result, the presence of two distinct relaxation processes is inferred: a slow one, occurring in the GHz window and having an essentially structural character, and a fast one, related instead to microscopic degrees of freedom. While the former originates a neat increase of the apparent, i.e. frequency-dependent, sound velocity, the latter induces no visible dispersive effects on the acoustic propagation. The observed behavior is likely paradigmatic of all glass formers near or below the melting and it is here discussed and explained in some detail. PMID:22850547

Cunsolo, Alessandro

2012-08-01

322

Remineralization of demineralized enamel by toothpastes: a scanning electron microscopy, energy dispersive X-ray analysis, and three-dimensional stereo-micrographic study.  

PubMed

Remineralization of hard dental tissues is thought to be a tool that could close the gap between prevention and surgical procedures in clinical dentistry. The purpose of this study was to examine the remineralizing potential of different toothpaste formulations: toothpastes containing bioactive glass, hydroxyapatite, or strontium acetate with fluoride, when applied to demineralized enamel. Results obtained by scanning electron microscopy (SEM) and SEM/energy dispersive X-ray analyses proved that the hydroxyapatite and bioactive glass-containing toothpastes were highly efficient in promoting enamel remineralization by formation of deposits and a protective layer on the surface of the demineralized enamel, whereas the toothpaste containing 8% strontium acetate and 1040 ppm fluoride as NaF had little, if any, remineralization potential. In conclusion, the treatment of demineralized teeth with toothpastes containing hydroxyapatite or bioactive glass resulted in repair of the damaged tissue. PMID:23659606

Gjorgievska, Elizabeta S; Nicholson, John W; Slipper, Ian J; Stevanovic, Marija M

2013-05-09

323

Remineralization of enamel subsurface lesions with casein phosphopeptide-amorphous calcium phosphate: A quantitative energy dispersive X-ray analysis using scanning electron microscopy: An in vitro study  

PubMed Central

Aim: The objective of this study was to quantitatively evaluate the remineralization potential of casein phosphopeptide-amor-phous calcium phosphate paste on enamel subsurface lesions using scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX). Materials and Methods: Ninety enamel specimens were prepared from extracted human molars. All specimens were evaluated for mineral content (% weight) using SEM-EDX. The specimens were placed in demineralizing solution for four days to produce artificial carious lesions. The mineral content (calcium/phosphorus ratios, Ca/P ratios) was remeasured using SEM-EDX. The specimens were then randomly assigned to five study groups and one control group of 15 specimens per group. Except for the control group, all group specimens were incubated in remineralizing paste (CPP-ACP paste) for 7, 14, 21, 28, and 35 days twice daily for three minutes. The control group received no treatment with remineralizing paste. All the 90 specimens were stored in artificial saliva at 37°C. After remineralization, the mineral content (% weight) of the samples was measured using SEM-EDX. Results: All the study groups showed very highly significant differences between Ca/P ratios of the demineralized and remineralized samples. There was no significant difference seen in the control group. Conclusion: CPP-ACP paste could significantly remineralize the artificial enamel subsurface lesions in vitro: the remineralizing rates increasing with the time for which the samples were kept in the remineralizing paste. Energy dispersive X-ray analysis is an efficient way to quantitatively assess the changes in mineral content during demineralization and in vitro remineralization processes.

Hegde, Mithra N; Moany, Anu

2012-01-01

324

Interface engineered ultrashort period Cr-Ti multilayers as high reflectance mirrors and polarizers for soft x rays of lambda = 2.74 nm wavelength  

Microsoft Academic Search

Cr-Ti multilayers with ultrashort periods of 1.39-2.04nm have been grown for the first time as highly reflective, soft-x-ray multilayer, near-normal incidence mirrors for transition radiation and Cherenkov radiation x-ray sources based on the Ti-2p absorption edge at E=452eV (lambda=2.74nm). Hard, as well as soft, x-ay reflectivity and transmission electron microscopy were used to characterize the nanostructure of the mirrors. To

Naureen Ghafoor; Per O. A. Persson; Jens Birch; Fredrik Eriksson; Franz Schaefers

2006-01-01

325

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

NASA Astrophysics Data System (ADS)

We have developed a method of dispersive x-ray absorption spectroscopy with a hard x-ray free electron laser (XFEL), generated by a self-amplified spontaneous emission (SASE) mechanism. A transmission grating was utilized for splitting SASE-XFEL light, which has a relatively large bandwidth (?E/E ~ 5 × 10-3), into several branches. Two primary split beams were introduced into a dispersive spectrometer for measuring signal and reference spectra simultaneously. After normalization, we obtained a Zn K-edge absorption spectrum with a photon-energy range of 210 eV, which is in excellent agreement with that measured by a conventional wavelength-scanning method. From the analysis of the difference spectra, the noise ratio was evaluated to be ~3 × 10-3, which is sufficiently small to trace minute changes in transient spectra induced by an ultrafast optical laser. This scheme enables us to perform single-shot, high-accuracy x-ray absorption spectroscopy with femtosecond time resolution.

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

2013-09-01

326

High-throughput x-ray characterization system for combinatorial materials studies  

Microsoft Academic Search

We have developed a high-throughput x-ray characterization system, which can rapidly screen structure, composition and x-ray scintillation of combinatorial materials libraries using energy-dispersive x-ray diffraction, x-ray fluorescence, and x-ray photoluminescence. This system consists of an x-ray source, a polycapillary x-ray lens, one or two x-ray energy detectors, and a fiber optic spectrometer. A Windows-based software package was also developed to

Zhenlin Luo; Bin Geng; Jun Bao; Cihui Liu; Wenhan Liu; Chen Gao; Zhiguo Liu; Xunliang Ding

2005-01-01

327

X-ray optics  

Microsoft Academic Search

Developments related to X-ray reflection are considered. The discovery that X-rays could be reflected at glancing incidence from polished surfaces opened up the possibility of making true X-ray imaging optics. However, to design usable X-ray optical systems, approaches had to be found for overcoming difficulties related to aberrations. The first X-ray microscope was constructed in 1948. Attention is also given

J. H. Underwood

1978-01-01

328

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

329

EMPIRICAL BACKGROUND CALCULATION METHOD FOR MULTI-CHANNEL X-RAY SPECTROMETERS  

EPA Science Inventory

A method of background calculation has been developed which is applicable to fixed-channel wavelength-dispersive spectrometers which cannot directly measure background. The x-ray intensities from a set of high- and low-average atomic number standards are fitted against Rayleigh a...

330

Determination of phosphorus in food samples by X-ray fluorescence spectrometry and standard spectrophotometric method  

Microsoft Academic Search

The Wavelength Dispersive X-ray fluorescence (WD XRF) determination of phosphorus in GMO and non GMO food samples is proposed. The tested materials included commercially available transgenic, unmodified soya-foods and popular dairy products. The WD XRF method was compared with the standard molybdenum blue method. Matrix effects were minimised by using standard reference material. Obtained results were discussed in respect of

A Jastrz?bska; B Brudka; T Szyma?ski; E Sz?yk

2003-01-01

331

A soft x-ray polarimeter designed for broadband x-ray telescopes  

Microsoft Academic Search

A novel approach for measuring linear X-ray polarization over a broad-band using conventional imaging optics and cameras is described. A new type of high efficiency grating, called the critical angle transmission grating is used to disperse soft X-rays radially from the telescope axis. A set of multilayer-coated paraboloids re-image the dispersed X-rays to rings in the focal plane. The intensity

Herman L. Marshall

2007-01-01

332

A Soft X-ray Polarimeter Designed for Broad-band X-ray Telescopes  

Microsoft Academic Search

A novel approach for measuring linear X-ray polarization over a broad-band using conventional imaging optics and cameras is described. A new type of high efficiency grating, called the critical angletransmission grating is used to disperse soft X-rays radially from the telescope axis. A set of multilayer-coated paraboloids re-image the dispersed X-rays to rings in the focal plane. The intensity variation

Herman L. Marshalla

333

Speciation of chromium in solid materials with the aid of soft-X-ray spectrometry  

NASA Astrophysics Data System (ADS)

Chromium compounds can be found in many different forms in steel and steel coatings. They are capable of strongly influencing the mechanical and technological properties of the material. Chromium occurs in steel mainly as a metal or in the carbide or nitride form. In the surface refinement of steel sheets, Cr(III) and Cr(VI) compounds are also used. With the development and optimisation of metallurgical processes, there is an increased demand for the determination of compounds in which chromium is present. X-Ray-spectra in the soft-X-ray area (2-15 nm) contain all the information necessary for characterisation and quantification of the chromium compounds. Generation and analysis of these X-ray spectra is in principle easily possible with a common wavelength-dispersive X-ray-fluorescence spectrometer. When an electron source for low-energy electrons (2-6 keV) is used instead of the usual X-ray tube, essentially better results are obtained, in comparison to the conventional X-ray-fluorescence spectrometer. The technical steps for changing an X-ray-fluorescence-spectrometer to a soft-X-ray-spectrometer are described. At the hand of the examination of galvanised steel sheets the analytical potential of this method was tested. The differentiation between Cr(III) and Cr(VI) is possible with sufficient precision.

Pappert, E.; Flock, J.; Broekaert, J. A. C.

1999-02-01

334

Copper Phosphonatoethanesulfonates: Temperature Dependent in Situ Energy Dispersive X-ray Diffraction Study and Influence of the pH on the Crystal Structures.  

PubMed

The system Cu(2+)/H(2)O(3)P-C(2)H(4)-SO(3)H/NaOH was investigated using in situ energy dispersive X-ray diffraction (EDXRD) to study the formation and temperature induced phase transformation of previously described copper phosphonosulfonates. Thus, the formation of [Cu(2)(O(3)P-C(2)H(4)-SO(3))(OH)(H(2)O)]·3H(2)O (4) at 90 °C is shown to proceed via a previously unknown intermediate [Cu(2)(O(3)P-C(2)H(4)-SO(3))(OH)(H(2)O)]·4H(2)O (6), which could be structurally characterized from high resolution powder diffraction data. Increase of the reaction temperature to 150 °C led to a rapid phase transformation to [Cu(2)(O(3)P-C(2)H(4)-SO(3))(OH)(H(2)O)]·H(2)O (1), which was also studied by in situ EDXRD. The comparison of the structures of 1, 4, and 6 allowed us to establish a possible reaction mechanism. In addition to the in situ crystallization studies, microwave assisted heating for the synthesis of the copper phosphonosulfonates was employed, which allowed the growth of larger crystals of [NaCu(O(3)P-C(2)H(4)-SO(3))(H(2)O)(2)] (5) suitable for single crystal X-ray diffraction. Through the combination of force field calculations and Rietveld refinement we were able to determine the crystal structure of [Cu(1.5)(O(3)P-C(2)H(4)-SO(3))] 2H(2)O (3) and thus structurally characterize all compounds known up to now in this well investigated system. With the additional structural data we are now able to describe the influence of the pH on the structure formation. PMID:23140328

Feyand, Mark; Hübner, Annika; Rothkirch, André; Wragg, David S; Stock, Norbert

2012-11-01

335

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

PubMed

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

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

2012-04-21

336

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

PubMed

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

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

2000-07-01

337

Imaging with x-ray lasers  

SciTech Connect

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

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

1993-11-01

338

Visible/IR light and x-rays in femtosecond synchronism from an x-ray free-electron laser.  

SciTech Connect

A way is proposed to obtain pulses of visible/infrared light in femtosecond synchronism with x-rays from an x-ray free-electron laser (XFEL), using the recently proposed emittance-slicing technique. In an XFEL undulator, only the short section of an electron bunch whose emittance is left unchanged by the slicing will emit intense coherent x-rays in the XFEL undulator. At the same time, the bunch emits highly collimated transition undulator radiation (TUR) into a cone whose opening angle is the reciprocal relativisticity parameter gamma. Due to the variation of the transverse momentum induced by the emittance slicing, the effective number of charges contributing to the TUR varies along the bunch, and is higher in the sliced-out part that emits the coherent x-rays. As with coherent synchrotron radiation (CSR), the TUR is thus coherently enhanced (CTUR) at near-infrared wavelengths. Coming from the same part of the bunch the CTUR and the coherent x-rays are perfectly synchronized to each other. Because both types of radiation are generated in the long straight XFEL undulator, there are no dispersion effects that might induce a timing jitter. With typical XFEL parameters, the energy content of the single optical cycle of near-IR CTUR light is about 100 Nano-Joule, which is quite sufficient for most pump-probe experiments.

Adams, B. A.; Experimental Facilities Division (APS)

2005-01-01

339

Development of X-ray laser media. Measurement of gain and development of cavity resonators for wavelengths near 130 angstroms, Volume 2  

SciTech Connect

The characteristic properties of multilayer reflectors for X-ray and XUV radiation (1A - 600A) permit solutions to Maxwell's equations for a quasi-periodic reflector whose layers may contain arbitrary index gradients. This solution can be formulated as a difference equation that propagates the amplitude reflectance across each layer pair. The difference equation resembles the Airy summation for single layers, but has a simpler Ricatti form. From the difference equation, design criteria can be derived for maximization of multilayer reflectivity. These criteria provide guidance in the selection of appropriate multilayer materials, and are used to derive approximate scaling laws for multilayer reflecting properties. The reflecting properties of X-ray multilayer devices are discussed.

Forsyth, J.M.

1983-02-01

340

The Use of Energy?Dispersive X?Ray Microanalysis as a Rapid Method for Demarcating Areas Around Marine Outfalls that may be Influenced by Effluent: A Case Study  

Microsoft Academic Search

Surveys that monitor pollution in a marine environment often include the measurement of heavy metals and other trace elements in sediments obtained from multiple stations near marine outfalls. This study investigates the use of energy?dispersive x?ray (EDX) microanalysis as a rapid screening method, where characteristic or “signature” elements (SE) in effluent can be located and mapped on the seabed. Thereafter,

Michael Alfred Gregory; Christopher John Brouckaert; Timothy Paul McClurg

2005-01-01

341

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

PubMed

In this article, we review current progress in the development of several techniques for extreme ultraviolet, soft x-ray, and x-ray optical instrumentation. Applications of these concepts include diagnostics of hot plasmas, spectroscopic studies of the interaction of multicharged ion beams with matter (atoms, ions, molecules, microstructures, surfaces, solids), and biomedical x-ray microscopy. Novel applications of components include the use of glass capillary converters (GCCs) and multilayer mirrors (MLMs) or crystals. GCC devices provide guiding, focusing, and polarization analysis of short wavelength radiation over a wide bandwidth. The MLM or crystal optical elements can be used for dispersing, focusing, and polarization-sensitive studies of radiation within a narrow bandwidth. In this report we focus on the development and testing of optical diagnostic devices for the short wavelength spectral region 0.1 nm < ? < 100 nm. PMID:21307546

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

1997-01-01

342

Invited article: The fast readout low noise camera as a versatile x-ray detector for time resolved dispersive extended x-ray absorption fine structure and diffraction studies of dynamic problems in materials science, chemistry, and catalysis  

Microsoft Academic Search

Originally conceived and developed at the European Synchrotron Radiation Facility (ESRF) as an ``area'' detector for rapid x-ray imaging studies, the fast readout low noise (FReLoN) detector of the ESRF [J.-C. Labiche, ESRF Newsletter 25, 41 (1996)] has been demonstrated to be a highly versatile and unique detector. Charge coupled device (CCD) cameras at present available on the public market

Jean-Claude Labiche; Olivier Mathon; Sakura Pascarelli; Mark A. Newton; Gemma Guilera Ferre; Caroline Curfs; Gavin Vaughan; Alejandro Homs; David Fernandez Carreiras

2007-01-01

343

Measuring the wavelengths of the Ni-like 4d 1S0 (arrow) 4p ; 1P1 and 4f 1P1 (arrow) 4d ; 1P1 x-ray laser lin  

Microsoft Academic Search

In this work we present measurements of the wavelengths of the nickel-like;\\u000a3d9 4d IS0 + 3d94p � P, X-ray laser line in several low-Z nickel-like ions ranging from;\\u000ayttrium (Z=39) to cadmium (Z=45). With the help of these laser results, we identify this;\\u000aline to very high accuracy in nonlasing plasmas from gallium (Z=3 1) to molybdenum;\\u000a(Z=42). The

S Churilov; J Nilsen; A Ryobtsev

1998-01-01

344

Diffraction efficiency and relative intensity of various x-ray analyzing crystals at Cu/sub K. cap alpha. / and Sn/sub K. cap alpha. / wavelengths and with two surface conditions  

SciTech Connect

Crystals used for x-ray analysis come in many useful planes and 2d spacings with great variation in diffraction efficiency. This report compares the diffraction efficiency of 13 different crystals at two wavelengths, Cu/sub K..cap alpha../ and Sn/sub K..cap alpha../, and with two surface conditions, first with a cleaved or polished surface and second with a ground or sandblasted surface for enhanced diffraction. It is not obvious from published information how to select a crystal for best detection efficiency for a given plane or 2d spacing. The information in this report should help users select a crystal for a specific application.

Sellick, B.O. Sr.

1978-04-01

345

X-Ray Optics.  

National Technical Information Service (NTIS)

This final scientific report covers research activities on X-Ray Optics. The report description is contained in the following sections: Preliminary Study of Source Coherency; Lloyd's Mirror Experiment; X-Ray Speckle; Measurement of Film Resolution; Experi...

N. George

1981-01-01

346

X-ray (image)  

MedlinePLUS

X-rays are a form of ionizing radiation that can penetrate the body to form an image on ... will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other ...

347

X Ray Topography  

ERIC Educational Resources Information Center

|Discusses some aspects in X-ray topography, including formation of dislocations, characteristics of stacking faults, x-ray contrast in defect inspection, Berg-Barrett technique, and Lang traversing crystal and Borrmann's methods. (CC)|

Balchin, A. A.

1974-01-01

348

Optimization of sample preparation for grazing emission X-ray fluorescence in micro- and trace analysis applications 1 This paper was presented at the 6th Conference on “Total Reflection X-Ray Fluorescence Analysis and Related Methods” (TXRF '96) held in two parts in Eindhoven (The Netherlands) and Dortmund (Germany) in June 1996, and is published in the Special Issue of Spectrochimica Acta, Part B, dedicated to that Conference. 1  

Microsoft Academic Search

Grazing emission X-ray fluorescence (GEXRF) is a new development in X-ray fluorescence analysis related to total-reflection XRF. An optical flat carrying the sample is irradiated at an angle of approximately 90° with an uncollimated polychromatic X-ray beam. The emitted fluorescent radiation of the sample elements is measured at very small angles using wavelength dispersive detection. For the application of GEXRF

Martine Claes; Pieter de Bokx; Nico Willard; Paul Veny; René Van Grieken

1997-01-01

349

X-Ray Telescopes  

NASA Astrophysics Data System (ADS)

X-ray telescopes produce images of x-ray-emitting objects within the telescope's FIELD OF VIEW by reflection from precisely shaped mirrors. Hans Wolter's design in the early 1950s of an x-ray microscope using reflective optics led Riccardo GIACCONI to suggest an `inverted' set of optics, not subject to the fabrication limitations of the microscope, could be used as a cosmic x-ray telescope. As de...

Reid, P.; Murdin, P.

2000-11-01

350

Soft x-ray polarimeter laboratory tests  

NASA Astrophysics Data System (ADS)

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

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

2010-07-01

351

Hand x-ray  

MedlinePLUS

X-ray - hand ... X-rays are a form of electromagnetic radiation like light, but of higher energy. They can pass through ... structures will be shades of gray. A hand x-ray is taken in a hospital radiology department or ...

352

X-Rays  

MedlinePLUS

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

353

Pelvis x-ray  

MedlinePLUS

X-ray - pelvis ... in the health care provider's office by an x-ray technician. You will be asked to lie down ... The x-ray is used to detect fractures , tumors, or degenerative conditions of bones in the hips, pelvis, and upper ...

354

X-ray spectropolarimeter.  

PubMed

We have constructed a novel single-crystal x-ray spectropolarimeter that separates spatially the two perpendicularly polarized components of an x-ray beam. We have tested this device by using an x-ray tube, and confirmed its performance to be satisfactory as expected from its design. PMID:19044334

Baronova, E O; Stepanenko, M M; Stepanenko, A M

2008-08-01

355

X-Rays  

MedlinePLUS

... X-Rays htmProcedureXray X-rays are waves of electromagnetic radiation that are used to form images of structures ... What Is It? X-rays are waves of electromagnetic radiation that are used to create images of organs ...

356

Soft X-ray Polarimetry  

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

357

Interface engineered ultrashort period Cr-Ti multilayers as high reflectance mirrors and polarizers for soft x rays of lambda = 2.74 nm wavelength  

SciTech Connect

Cr-Ti multilayers with ultrashort periods of 1.39-2.04nm have been grown for the first time as highly reflective, soft-x-ray multilayer, near-normal incidence mirrors for transition radiation and Cherenkov radiation x-ray sources based on the Ti-2p absorption edge at E=452eV (lambda=2.74nm). Hard, as well as soft, x-ay reflectivity and transmission electron microscopy were used to characterize the nanostructure of the mirrors. To achieve minimal accumulated roughness, improved interface flatness, and to avoid intermixing at the interfaces, each individual layer was engineered by use of a two-stage ion assistance process during magnetron sputter deposition: The first 0.3nm of each Ti and Cr layer was grown without ion assistance, and the remaining 0.39-0.72nm of the layers were grown with high ion-neutral flux ratios Phi(PhiTi=3.3,PhiCr=2.2) and a low energy Eion (ETi=23.7andECr=21.2), ion assistance. A maximum soft-x-ray reflectivity of R=2.1% at near-normal incidence ({approx}78.8 deg.) was achieved for a multilayer mirror containing 100 bilayers with a modulation period of 1.379nm and a layer thickness ratio of Gamma=0.5. For a polarizing multilayer mirror with 150 bilayers designed for operation at the Brewster angle, 45 deg., an extinction ratio, Rs/Rp, of 266 was achieved with an absolute reflectivity of R=4.3%.

Ghafoor, Naureen; Persson, Per O. A.; Birch, Jens; Eriksson, Fredrik; Schaefers, Franz

2006-01-01

358

Theoretical structures of the satellite and hypersatellite M-x-ray lines of uranium  

NASA Astrophysics Data System (ADS)

The structure of satellite (additional vacancies in N and/or O shells) and hypersatellite (additional vacancies in M or M and N shells) M?1,2 and M?1 lines in the x-ray spectra of heavy atoms can be explained precisely by taking into account the extensive multiconfiguration Dirac-Fock calculations. The presented results are a precursor for the reliable quantitative interpretation of a very complex origin structure of M?1,2 and M?1 lines in various high-resolution x-ray spectra of heavy atoms induced by different light and heavy projectiles. Moreover, the intensities of the M-x-ray lines of uranium can be helpful in the application of x-ray measurements from UO2 as a reference material (virtual standard) for non-destructive wavelength-dispersive electron probe microanalysis.

Starosta, J.; Polasik, M.; S?abkowska, K.

2013-09-01

359

Crystal optics for hard-X-ray spectroscopy of highly charged ions  

NASA Astrophysics Data System (ADS)

A twin crystal-spectrometer assembly, operated in the focusing compensated asymmetric Laue geometry has been developed for accurate spectroscopy of fast highly charged heavy ions in the hard-X-ray region. Coupled to the focusing crystal optics is a specially developed two-dimensional position-sensitive X-ray detector which is necessary for retaining spectral resolution also for fast moving sources. We summarize the crystal optics and demonstrate the usefulness of the instrument for spectroscopy of both stationary and fast moving X-ray sources. Results are reported from several tests employing a 169Yb gamma-ray source and the Lyman radiation of one-electron Pb 81+ ions traveling at a velocity corresponding to ? ? v/ c ? 0.59. The features of the instrument presented may be useful in many applications where it appears difficult to make the leap from conventional X-ray energy measurements to wavelength-dispersive spectroscopy based on crystal optics.

Beyer, H. F.; Attia, D.; Banas, D.; Le Bigot, E.-O.; Bosch, F.; Dousse, J.-Cl.; Förster, E.; Gumberidze, A.; Hagmann, S.; Heß, S.; Hoszowska, J.; Indelicato, P.; Jagodzinski, P.; Kozhuharov, Chr.; Krings, Th.; Liesen, D.; Ma, X.; Manil, B.; Mohos, I.; Pajek, M.; Proti?, D.; Reuschl, R.; Rzadkiewicz, J.; Simionovici, A.; Spillmann, U.; Stachura, Z.; Stöhlker, Th.; Trassinelli, M.; Trotsenko, S.; Warczak, A.; Wehrhan, O.; Ziegler, E.

2009-08-01

360

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

NASA Astrophysics Data System (ADS)

The in-situ growth of CuO nanowires was studied by Energy Dispersive X-ray Diffraction (EDXRD) to observe the mechanism of growth. The study was carried out for comparison at two temperatures--at 500 °C, the optimum temperature of the nanowires growth, and at 300 °C just below the temperature range of the growth. The in situ observation revealed the successive oxidation of Cu foil to Cu2O layer and finally to CuO layer. Further analysis showed the presence of a compressive stress in CuO layer due to interface at CuO and Cu2O layers. The compressive stress was found to increase with the growth of the nanowires at 500 °C while it relaxed with the growth of CuO layer at 300 °C. The present results do not support the existing model of stress relaxation induced growth of nanowires. Based on the detailed Transmission Electron Microscope, Scanning Electron Microscope, and EDXRD results, a microstructure based growth model has been suggested.

Srivastava, Himanshu; Ganguli, Tapas; Deb, S. K.; Sant, Tushar; Poswal, H. K.; Sharma, Surinder M.

2013-10-01

361

In Vitro assessment of dentin erosion after immersion in acidic beverages: surface profile analysis and energy-dispersive X-ray fluorescence spectrometry study.  

PubMed

The aim of this study was to investigate the effects of some acidic drinks on dentin erosion, using methods of surface profile (SP) analysis and energy-dispersive X-ray fluorescence spectrometry (EDXRF). One hundred standardized dentin slabs obtained from bovine incisor roots were used. Dentin slabs measuring 5x5 mm were ground flat, polished and half of each specimen surface was protected with nail polish. For 60 min, the dentin surfaces were immersed in 50 mL of 5 different drinks (Gatorade®, Del Valle Mais orange juice®, Coca-Cola®, Red Bull® and white wine), 20 blocks in each drink. The pH of each beverage was measured. After the erosive challenge, the nail polish was removed and SP was analyzed. The mineral concentration of dentin surfaces was determined by means of EDXRF. Data were analyzed statistically by ANOVA and Tukey's test (?=0.05). SP analysis showed that Red-Bull had the highest erosive potential (p<0.05). EDXRF results exhibited a decrease in phosphate in the groups immersed in Red-Bull, orange juice and white wine (p<0.05), and no significant difference in calcium content between the reference surface and eroded surface. In conclusion, this study demonstrated that all studied beverages promoted erosion on root dentin and Red Bull had the highest erosive potential. There was no correlation between pH of beverages and their erosive potential and only the P content changed after erosive challenge. PMID:23207852

Caneppele, Taciana Marco Ferraz; Jeronymo, Raffaela Di Iorio; Di Nicoló, Rebeca; de Araújo, Maria Amélia Máximo; Soares, Luís Eduardo Silva

2012-01-01

362

Ultrastructure and energy-dispersive x-ray microanalysis of cartilage after rapid freezing, low temperature freeze drying, and embedding in Spurr's resin  

SciTech Connect

In order to undertake meaningful high-resolution x-ray microanalysis of tissues, methods should be used that minimize the introduction of artefacts produced by loss or translocation of ions. The most ideal method is rapid freezing but the subsequent sectioning of frozen tissues is technically difficult. An alternative method is to freeze dry the tissues at a low temperature, and then embed them in resin. This facilitates the rapid production of reproducible thin sections. With freeze-dried, embedded hypertrophic cartilage, the morphology was similar to that seen using aqueous fixatives even when no additional electron density is introduced by the use of osmium vapor. Energy-dispersive analysis of specific areas show that little or no loss or migration of ions occurs from structures such as mitochondria. Mitochondrial granules consisting of calcium and phosphorus precipitates were not observed except where the cells were damaged as a result of the freezing process. This may suggest that these granules only appear when tissue is damaged because of inadequate preservation.

Appleton, J.; Lyon, R.; Swindin, K.J.; Chesters, J.

1985-10-01

363

Analysis of trace elements during different developmental stages of somatic embryogenesis in Plantago ovata Forssk using energy dispersive X-ray fluorescence.  

PubMed

Energy dispersive X-ray fluorescence (ED-XRF) technique has been used for the determination of trace element profile during different developmental stages of somatic embryogenic callus of an economically important medicinal plant, Plantago ovata Forssk. Somatic embryogenesis is a plant tissue culture-based technique, which is used for plant regeneration and crop improvement. In the present investigation, elemental content was analysed using ED-XRF technique during different developmental stages and also determine the effect of additives--casein hydrolysate and coconut water on the trace elemental profile of embryogenic callus tissue of P. ovata. Subsequent experiments showed significant alteration in the concentration of K, Ca, Mn, Fe, Zn, Cu, Br, and Sr in both the embryogenic and non-embryogenic callus. Higher K, Ca, Fe, Cu, and Zn accumulation was in embryogenic tissue stage compared to other stages, suggesting these elements are crucial for successful embryogenesis. The results suggest that this information could be useful for formulating a media for in vitro embryo induction of P. ovata. PMID:19696971

Saha, Priyanka; Raychaudhuri, Sarmistha Sen; Sudarshan, Mathummal; Chakraborty, Anindita

2009-08-21

364

Observation of bulk band dispersions of YbRh2Si2 using soft x-ray angle-resolved photoemission spectroscopy  

NASA Astrophysics Data System (ADS)

We have performed soft x-ray angle-resolved photoemission spectroscopy (ARPES) measurements on YbRh2Si2 and clarified its three-dimensional bulk valence-band structures. The ARPES spectra have not only Yb3+ multiplet peaks but also a finite contribution of Yb2+ peaks at 15 K, corresponding to the valence fluctuating behavior in this compound. This means that Yb 4f electrons in this compound have itinerant character below the TK. We have found that dispersions of the valence bands except the vicinity of the Yb 4f bands agree better with those of the band-structure calculation of LuRh2Si2 than those of YbRh2Si2 within a local-density approximation. In addition, the Yb 3d-4f resonant photoemission spectra of YbRh2Si2 strongly suggest the existence of Yb 5d electrons in the valence band. We conclude that the charge transfer from the Yb 4f state to the Yb 5d state has an important role in the formation of the valence band of YbRh2Si2.

Yasui, A.; Saitoh, Y.; Fujimori, S.-i.; Kawasaki, I.; Okane, T.; Takeda, Y.; Lapertot, G.; Knebel, G.; Matsuda, T. D.; Haga, Y.; Yamagami, H.

2013-02-01

365

Elemental relationships in rock varnish as seen with SEM/EDX (scanning electron microscopy/energy dispersive x-ray) elemental line profiling  

SciTech Connect

The heterogeneous nature of rock varnish requires a thorough survey of elemental and mineralogic compositions before relating chemical variability of rock varnish to past geochemical environments. Elemental relationships in rock varnish can be examined using scanning electron microscopy (SEM) in conjunction with an elemental line profiling routine using semi-quantitative, energy dispersive x-ray (EDX) analysis. Results of SEM/EDX analysis suggest: variations in cation concentrations used in varnish cation ratio dating relate more specifically to variations in detritus within the varnish than to element mobility as defined by weathering indices; Mn concentration rather than Mn:Fe ratios may be a more appropriate indicator of paleoclimatic fluctuations; and the Mn-oxide phase existing in varnish is most likely a Ba-enriched phase rather than birnessite. Element line profiling offers great potential for gaining insights into geochemical processes affecting the deposition and diagenesis of rock varnish and for testing hypotheses relating to its chemical variability. 27 refs., 9 figs.

Raymond, R. Jr.; Reneau, S.L.; Harrington, C.D.

1990-01-01

366

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

PubMed

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

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

2013-07-01

367

In situ strain profiling of elastoplastic bending in Ti-6Al-4V alloy by synchrotron energy dispersive x-ray diffraction  

SciTech Connect

Elastic and plastic strain evolution under four-point bending has been studied by synchrotron energy dispersive x-ray diffraction. Measured strain profiles across the specimen thickness showed an increasing linear elastic strain gradient under increasing four-point bending load up to approx2 kN. The bulk elastic modulus of Ti-6Al-4V was determined as 118 GPa. The onset of plastic deformation was found to set in at a total in-plane strain of approx0.008, both under tension and compression. Plastic deformation under bending is initiated in the vicinity of the surface and at a stress of 1100 MPa, and propagates inward, while a finite core region remains elastically deformed up to 3.67 kN loading. The onset of the plastic regime and the plastic regime itself has been verified by monitoring the line broadening of the (100) peak of alpha-Ti. The effective compression/tension stress-strain curve has been obtained from the scaling collapse of strain profile data taken at seven external load levels. A similar multiple load scaling collapse of the plastic strain variation has also been obtained. The level of precision in strain measurement reported herein was evaluated and found to be 1.5x10{sup -5} or better.

Croft, M. [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States); National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States); Shukla, V.; Akdogan, E. K.; Sadangi, R.; Ignatov, A.; Balarinni, L.; Tsakalakos, T. [Department of Materials Science and Engineering, Rutgers University, Piscataway, New Jersey 08854 (United States); Jisrawi, N. [Department of Materials Science and Engineering, Rutgers University, Piscataway, New Jersey 08854 (United States); Department of Applied Physics, University of Sharjah, P.O. Box 27272, Sharjah (United Arab Emirates); Zhong, Z. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States); Horvath, K. [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States)

2009-05-01

368

X-ray photon spectroscopy calculations  

SciTech Connect

X-ray photons - as many other particles - interact with matter producing secondary radiation that carries useful information about the atoms comprising the target. The availability of intense sources of highly monochromatic X-rays and the great improvement in detector technology intensified research in X-ray spectrometry in the last twenty years. New techniques allowed the attenuation coefficients and the physics of the atom to be better known: Extended X-ray Absorption Fine Structure (EXAFS), X-ray Absorption Near Edge Structure (XANES), and Inelastic X-ray Scattering Spectroscopy (IXSS). Old techniques, like X-ray Fluorescence (XRF), gained in precision thus extending the horizon of applicability to new elements and energy ranges, and consequently Energy Dispersive X-ray Fluorescence (EDXRF) and Synchrotron Radiation X-ray Fluorescence (SRXRF) were evolved. Particle induced X-ray emission spectroscopy also benefited from this improvement. The field of application of X-ray spectrometry has grown from atomic, to nuclear, to plasma physics, to astrophysics. In this work the authors summarize the knowledge recently gained about how the intensity due to multiple scattering perturbs the first-order terms of the three processes of main interest in X-ray spectrometry between 1 keV and 100 keV: the photoelectric, the Rayleigh and the Compton effects. They show that the contribution of a few orders of scattering, calculated in the frame of transport theory, allows the construction of a theoretical X-ray spectrum that matches well experimental data from targets of homogeneous composition and infinite thickness. 99 refs., 15 figs.

Fernandez, J.E.; Molinari, V.G. [Univ. of Bologna (Italy)

1991-12-31

369

Wavelength switching in an actively mode-locked FPLD coupled with a high dispersive external cavity  

NASA Astrophysics Data System (ADS)

We report that simple wavelength switching technique based on actively mode-locked Fabry-Perot laser diode (FPLD) coupled with high dispersion external cavity by slightly detuning the modulation frequency. When dispersion compensating fiber (DCF) with dispersion, -100ps/km/nm at 1550 nm, is used for timing filter, peak wavelength of the optical pulse switched from the shorter FP longitudinal mode to the longer FP longitudinal mode. Wavelength switching from the longer FP longitudinal mode to the shorter FP longitudinal mode was achieved by adopting a length of single mode fiber with dispersion, 16ps/km/nm at 1550 nm.

Kim, Youngjae; Kim, Dug Young

2006-03-01

370

A Synthesis Of Cosmic X-ray And Infrared Background  

NASA Astrophysics Data System (ADS)

We present a synthesis model of cosmic IR and X-ray background, with the goal to derive a complete census of cosmic evolution of star formation (SF) and black-hole (BH) growth by complementing advantages of X-ray and IR surveys to each other. By assuming that individual galaxies are experiencing both SF and BH accretion, our model decomposes the total IR LF into SF and BH components while taking into account the luminosity-dependent SED and its dispersion of the SF component, and the extinction-dependent SED of the BH component. The best-fit parameters are derived by fitting to the number counts and redshift distributions at X-ray including both hard and soft bands, and mid-IR to submm bands including IRAS, Spitzer, Herschel, SCUBA, Aztec and MAMBO. Based on the fit result, our models provide a series of predictions on galaxy evolution and black-hole growth. For evolution of infrared galaxies, the model predicts that the total infrared luminosity function is best described through evolution in both luminosity and density. For evolution of AGN populations, the model predicts that the evolution of X-ray LF also shows luminosity and density dependent, that the type-1/type-2 AGN fraction is a function of both luminosity and redshift, and that the Compton-thick AGN number density evolves strongly with redshift, contributing about 20% to the total cosmic BH growth. For BH growth in IR galaxies, the model predicts that the majority of BH growth at z>1 occurs in infrared luminous galaxies and the AGN fraction as a function of IR survey is a strong function of the survey depth, ranging from >50% at bright end to below 10% at faint end. We also evaluates various AGN selection techniques at X-ray and IR wavelengths and offer predictions for future missions at X-ray and IR.

Shi, Yong; Helou, G.; Armus, L.; Stierwalt, S.

2012-01-01

371

X-ray spectromicroscopy in soil and geosciences  

NASA Astrophysics Data System (ADS)

X-ray microscopy achieves a much higher resolution than light microscopy due to their much shorter wavelength compared to visible light. The smallest structures that can be seen in an X-ray microscope at present are reaching the 10 nm size range. The technique is capable of imaging specimens directly in aqueous media. By choosing the used X-ray energy appropriately, it is possible to perform spectromicroscopy studies. Comprising, it is a powerful tool for addressing key questions in many scientific areas, e.g. to study structures in the environment showing dimensions on the nanoscale. As a result of the refractive index of matter being close to unity scattered X-ray light will not be reflected from inner surfaces in inhomogeneous media. Clear images without scattering background are obtained even when studying thick and inhomogeneous samples. Therefore, X-ray microscopy images can be used for tomographic reconstructions of thick samples. Electron storage rings, being X-ray light sources of extreme brightness, are normally the site of installation for X-ray microscopes, however, small scale laboratory X-ray sources have already proven their value for imaging and spectroscopy. Applications from soil science, geomicrobiology and water chemistry show the significance of X-ray spectromicroscopy as a tool to study the submicron world. Samples from soils and groundwater aquifers have been imaged to visualize the appearance of structures on the nano- and microscale. The effect of changing chemical conditions in an aqueous environment on the appearance of these structures has been imaged and evaluated. Using the spectromicroscopy potential, the distribution of organic and inorganic components has been studied; spectra have been analyzed for major chemical constituents. For example, anthropogenically produced nanoparticles and their effects in the environment have been studied. Spectromicroscopy has been used as well to assess different sulfur and iron species in an entire soil profile. Clay dispersions, microhabitats, and morphological effects of biologically induced redox changes of humic substances have been imaged tomographically conveying a detailed three-dimensional presentation of the specimen structure.

Thieme, J.

2009-04-01

372

BENT CRYSTAL. X-ray spectrograph design  

SciTech Connect

BENT CRYSTAL analyzes x-ray spectrographs for which the Bragg diffraction crystal is either flat or circularly bent and for which the film lies in a plane. Only the behavior in a plane is examined. The geometry is specified by either giving the source to crystal and crystal to film plane distances for an x-ray of specified energy, or by giving the coordinates of the source of a point on the film plane and of the center of curvature of the crystal if curved or of a point on it if flat. In both cases, the radius of curvature and film plane azimuth must also be specified. Filters may be placed at the front of the spectrograph or at the film plane. One specifies a set of energies at which the spectrograph geometry is to be solved. Many different quantities are computed, any of which can be plotted against any other. Some of the computed quantities are: the positions on the film, the angles to the film normal, all the lengths and angles including the Bragg angles, the energies and wavelengths, the dispersions, the filter transmissions, crystal reflectivities, source broadening factors, and the spectrograph sensitivities in terms of the film exposures in photons/cm**2 divided by the source brightness. The plots may be saved or printed, their axes made either linear or logarithmic, and grid lines drawn at major or minor guidelines on either axis.

Phillion, D. [Lawrence Livermore National Lab., Livermore, CA (United States)

1991-08-28

373

X-ray Polarimetry  

NASA Astrophysics Data System (ADS)

1. X-ray polarimetry: historical remarks and other considerations; Part I. Polarimetry Techniques: 2. Scattering polarimetry in high energy astronomy; 3. Photoelectric polarimeters; 4. Bragg crystal polarimeters; 5. X-ray polarimetry with the photon counting pixel detector timepix; 6. HE polarized photon interactions with matter: simulations with geant4; 7. The GPD as a polarimeter: theory and facts; 8. Ideal gas electron multipliers (GEMs) for x-ray polarimeters; 9. Broad-band soft x-ray polarimetry; 10. Feasibility of x-ray photoelectric polarimeters with large field of view; 11. Angular resolution of a photoelectric polarimeter; 12. Development of a Thomson x-ray polarimeter; 13. Hard x / soft gamma ray polarimetry using a Laue lens; Part II. Polarized Emission in X-ray Sources: 14. Probing strong gravity effects with x-ray polarimetry; 15. X-ray polarization from black holes in the thermal state; 16. Strong-gravity effects acting on polarization from orbiting spots; 17. Polarization of thermal emission from accreting black holes; 18. X-ray polarimetry and radio-quiet AGN; 19. The soft x-ray polarization in obscured AGN; 20. The polarization of complex x-ray sources; 21. Polarization of Compton x-rays from jets in AGN; 22. Polarization of x-ray lines from galaxy clusters and elliptical galaxies; 23. Polarization characteristics of rotation-powered pulsars; 24. Polarized x-rays from magnetized neutron stars; 25. Polarization properties of x-ray millisecond pulsars; 26. X-ray polarization signatures of neutron stars; 27. Polarization from the oscillating magnetized accretion torus; 28. X-ray polarization from accreting white dwarfs and associated systems; 29. Polarization of pulsar wind nebulae; 30. X-ray polarization of gamma-ray bursts; 31. Central engine afterglow from GRBs and the polarization signature; 32. GRB afterglow polarimetry. Past, present and future; 33. Gamma-ray polarimetry with SPI; 34. INTEGRAL/IBIS observations of the Crab Nebula and GRB 041219A; 35. Fermi results on the origin of high energy emission in pulsars; 36. Diagnostics of the evolution of spiral galaxies in a cluster environment; Part III. Future Missions: 37. Gravity and extreme magnetism SMEX (GEMS); 38. Programs of x-ray polarimetry in Italy; 39. A polarimeter for IXO; 40. Polarimetry with ASTRO-H soft gamma-ray detector; 41. EXIST and its polarization sensitivity; 42. PoGOLite: a balloon-borne soft gamma-ray polarimeter; 43. Studies of neutron background rejection in the PoGOLite polarimeter; 44. Observing polarized x-rays with PoGOLite; 45. Pre-flight qualification tests of the PoGOLite detector system; 46. The gamma-ray polarimeter experiment (GRAPE) Balloon Payload; 47. POLAR: an instrument dedicated to GRB polarization measurement; 48. Polarisation detection capability of GRIPS; 49. X-ray and y-ray polarimetry small satellite mission polaris; 50. GAP aboard the solar powered sail mission; 51. Hard x-ray polarimeter for small satellite missions; 52. Performance of hard x-ray polarimeter: PHENEX; 53. GRB polarimetry with POET; Index.

Bellazzini, Ronaldo; Costa, Enrico; Matt, Giorgio; Tagliaferri, Gianpiero

2010-07-01

374

Molecular and elemental characterisation of mineral particles by means of parallel micro-Raman spectrometry and Scanning Electron Microscopy\\/Energy Dispersive X-ray Analysis  

Microsoft Academic Search

The “fingerprinting” of a molecular structure obtained by micro-Raman spectroscopy (MRS) can be successfully complemented by means of X-ray spot analysis through the application of scanning electron microscopy equipped with an X-ray detector (SEM\\/EDX). The elemental composition revealed by SEM\\/EDX is essential for a correct interpretation of the collected Raman spectra. The results presented here illustrate how the two techniques

E. A. Stefaniak; A. Worobiec; S. Potgieter-Vermaak; A. Alsecz; S. Török; R. Van Grieken

2006-01-01

375

Analysis of eight argonne premium coal samples by X-ray fluorescence spectrometry  

USGS Publications Warehouse

X-ray fluorescence spectrometric methods were used in the analysis of eight Argonne Premium Coal Samples. Trace elements (Cr, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, La, and Ce) in coal ash were determined by energy-dispersive X-ray fluorescence spectrometry; major elements (Na, Mg, Al, Si, P, S, K, Ca, Ti, Mn, and Fe) in coal ash and trace elements (Cl and P) in whole coal were determined by wavelength-dispersive X-ray fluorescence spectrometry. The results of this study will be used in a geochemical database compiled for these materials from various analytical techniques. The experimental XRF methods and procedures used to determine these major and trace elements are described.

Evans, J. R.; Sellers, G. A.; Johnson, R. G.; Vivit, D. V.; Kent, J.

1990-01-01

376

X-ray microscopy  

Microsoft Academic Search

Ever since W. C. Röntgen discovered his x-rays there was a desire to create a useful x-ray microscopy. The fact that the index of refraction deviates so little from that of vacuum causes, however, great difficulties in developing suitable x-ray optical elements. Quite generally, the low efficiency even of the now existing optical elements and the low brilliance of classical

C. Kunz

1996-01-01

377

X ray imaging system  

NASA Astrophysics Data System (ADS)

The invention provides a method and apparatus for focusing and imaging x-rays. An opaque sphere is used as a diffractive imaging element to diffract x-rays from an object. The divergent x-ray wavefronts are then transformed into convergent wavefronts. The convergent wavefronts are brought into focus to form an image of the object. The new image has a large depth of field.

Sommargren, G. E.; Weaver, H. J.

1990-04-01

378

X ray imaging system  

Microsoft Academic Search

The invention provides a method and apparatus for focusing and imaging x-rays. An opaque sphere is used as a diffractive imaging element to diffract x-rays from an object. The divergent x-ray wavefronts are then transformed into convergent wavefronts. The convergent wavefronts are brought into focus to form an image of the object. The new image has a large depth of

G. E. Sommargren; H. J. Weaver

1990-01-01

379

Information-theoretical feature selection using data obtained by scanning electron microscopy coupled with and energy dispersive X-ray spectrometer for the classification of glass traces.  

PubMed

In this work, a selection of the best features for multivariate forensic glass classification using Scanning Electron Microscopy coupled with an Energy Dispersive X-ray spectrometer (SEM-EDX) has been performed. This has been motivated by the fact that the databases available for forensic glass classification are sparse nowadays, and the acquisition of SEM-EDX data is both costly and time-consuming for forensic laboratories. The database used for this work consists of 278 glass objects for which 7 variables, based on their elemental compositions obtained with SEM-EDX, are available. Two categories are considered for the classification task, namely containers and car/building windows, both of them typical in forensic casework. A multivariate model is proposed for the computation of the likelihood ratios. The feature selection process is carried out by means of an exhaustive search, with an Empirical Cross-Entropy (ECE) objective function. The ECE metric takes into account not only the discriminating power of the model in use, but also its calibration, which indicates whether or not the likelihood ratios are interpretable in a probabilistic way. Thus, the proposed model is applied to all the 63 possible univariate, bivariate and trivariate combinations taken from the 7 variables in the database, and its performance is ranked by its ECE. Results show remarkable accuracy of the best variables selected following the proposed procedure for the task of classifying glass fragments into windows (from cars or buildings) or containers, obtaining high (almost perfect) discriminating power and good calibration. This allows the proposed models to be used in casework. We also present an in-depth analysis which reveals the benefits of the proposed ECE metric as an assessment tool for classification models based on likelihood ratios. PMID:21962363

Ramos, Daniel; Zadora, Grzegorz

2011-05-24

380

Phase Separation in Binary Mixtures of Bipolar and Monopolar Lipid Dispersions Revealed by 2H NMR Spectroscopy, Small Angle X-Ray Scattering, and Molecular Theory  

PubMed Central

Abstract Binary mixtures of C20BAS and POPC membranes were studied by solid-state 2H NMR spectroscopy and small angle x-ray scattering (SAXS) over a wide range of concentrations and at different temperatures. Three specifically deuterated C20BAS derivatives—[1?,1?,20?,20?-2H4]C20BAS, [2?,2?,19?,19?-2H4]C20BAS, and [10?,11?-2H2]C20BAS—combined with protiated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), as well as membranes containing POPC-d31 and fully protiated bolalipid, were used in NMR experiments to obtain structural information for the mixtures. The 2H NMR spectra of [10?,11?-2H2]C20BAS/POPC membrane dispersions reveal that the bolalipid is predominantly in the transmembrane conformation at high bolalipid concentrations (100, 90, and 70 mol %). At ?50 mol % C20BAS, smaller quadrupolar couplings appear in the spectra, indicating the presence of U-shaped conformers. The proportion of U-shaped bolalipids increases as the amount of POPC in the membrane increases; however, the transmembrane component remains the dominant bolalipid conformation in the membrane even at 45°C and 10 mol % C20BAS, where it accounts for ?50% of the bolalipid population. The large fraction of C20BAS transmembrane conformers, regardless of the C20BAS/POPC ratio, together with the findings from molecular mean-field theory calculations, suggests the coexistence of phase-separated bolalipid-rich domains and POPC-rich domains. A single lamellar repeat distance was observed in SAXS experiments corresponding to the average repeat spacing expected for C20BAS- and POPC-rich domains. These observations are consistent with the presence of microphase-separated domains in the mixed membrane samples that arise from POPC-C20BAS hydrophobic mismatch.

Brownholland, David P.; Longo, Gabriel S.; Struts, Andrey V.; Justice, Matthew J.; Szleifer, Igal; Petrache, Horia I.; Brown, Michael F.; Thompson, David H.

2009-01-01

381

X-Ray diffraction and scanning electron microscopy-energy dispersive spectroscopic analysis of ceram?metal interface at different firing temperatures  

PubMed Central

Objective: Porcelain chipping from porcelain fused to metal restoration has been Achilles heel till date. There has been advent of newer ceramics in past but but none of them has been a panacea for Porcelain fracture. An optimal firing is thus essential for the clinical success of the porcelain-fused to metal restoration. The aim of the present study was to evaluate ceramo-metal interface at different firing temperature using XRD and SEM-EDS analysis. Clinical implication of the study was to predict the optimal firing temperature at which porcelain should be fused with metal in order to possibly prevent the occasional failure of the porcelain fused to metal restorations. Materials and Methods: To meet the above-mentioned goal, porcelain was fused to metal at different firing temperatures (930–990°C) in vacuum. The microstructural observations of interface between porcelain and metal were evaluated using X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. Results: Based on the experimental investigation of the interaction zone of porcelain fused to metal samples, it was observed that as the firing temperature was increased, the pores became less in number as well as the size of the pores decreased at the porcelain/metal interface upto 975°C but increased in size at 990°C. The least number of pores with least diameter were found in samples fired at 975°C. Several oxides like Cr2O3, NiO, and Al2O3 and intermetallic compounds (CrSi2, AlNi3) were also formed in the interaction zone. Conclusions It is suggested that the presence of pores may trigger the crack propagation along the interface, causing the failure of the porcelain fused to metal restoration during masticatory action.

Saini, Monika; Chandra, Suresh; Singh, Yashpal; Basu, Bikramjit; Tripathi, Arvind

2010-01-01

382

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

PubMed

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

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

2006-07-08

383

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

PubMed

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

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

2012-07-11

384

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

SciTech Connect

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

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

2012-10-15

385

X-ray Interferometry  

NASA Astrophysics Data System (ADS)

X-ray interferometry is well on its way to becoming a reality. We present an update on MAXIM, the Micro-Arcsecond X-ray Imaging Mission. With the eventual goal of imaging the event horizon of a black hole, MAXIM will require a phased array of x-ray mirrors across a one kilometer aperture. Recent design advances, backed by demonstrations in the laboratory have established that such a mission is not only feasible, but affordable. Soon, x-ray observatories may rise to the standards set by radio astronomers.

Cash, W.

2005-12-01

386

Multilayer X-ray Optical Systems for Future X-ray Astronomy Missions  

Microsoft Academic Search

The development of multilayers makes it possible to construct a normal incidence soft X ray telescope with high angular resolution and a grazing incidence hard X ray telescope sensitive up to 100 keV using a multilayer supermirror. A multilayer coated grating is also a useful dispersive element with high efficiency and spectral resolution in the Extreme Ultraviolet Radiation (EUV) and

Koujun Yamashita

1997-01-01

387

PORTABLE VACUUM X-RAY SPECTROMETER INSTRUMENT FOR ON-SITE ANALYSIS OF AIRBORNE PARTICULATE SULFUR AND OTHER ELEMENTS  

EPA Science Inventory

A portable vacuum wavelength-dispersive x-ray analyzer has been constructed for on-site measurement of the sulfur content of filter-deposited airborne particles. Although designed to analyze for sulfur, the spectrometer is adjustable over a limited range providing the potential f...

388

Simultaneous determination of parts-per-million level Cr, As, Cd and Pb, and major elements in low level contaminated soils using borate fusion and energy dispersive X-ray fluorescence spectrometry with polarized excitation  

Microsoft Academic Search

Energy-dispersive polarized X-ray fluorescence (ED-P-XRF) spectrometry was evaluated for the analysis of low level contaminated soils for four important contaminant elements (Cr, As, Cd and Pb) and major elements (Fe, Mn, Ti, P, Ca, K, Si, Al, Mg and Na) commonly found in soils. Using a LiBO2 and Li2B4O7 fusion method, synthetic standards were prepared in Al2O3 matrices for trace

Terrance D. Hettipathirana

2004-01-01

389

Limitations of ZAF correction factors in the determination of calcium\\/phosphorus ratios: Important forensic science considerations relevant to the analysis of bone fragments using scanning electron microscopy and energy-dispersive x-ray microanalysis  

Microsoft Academic Search

A series of calcium phosphate standards having calcium\\/phosphorus (Ca\\/P) molar ratios of 0.50, 1.00, 1.50, and 1.67, respectively, was prepared for bulk specimen analysis using scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDXA). The standards were mounted on carbon planchettes as either pure crystals or crystals embedded in epoxy resin. Ten different samples of each embedded and non-embedded standard

C. M. Payne; D. W. Cromey

1990-01-01

390

Selective scavenging of copper, zinc, lead, and arsenic by iron and manganese oxyhydroxide coatings on plankton in lakes polluted with mine and smelter wastes: results of energy dispersive X-ray micro-analysis  

Microsoft Academic Search

Energy dispersive X-ray micro-analyses of the remains of individual organisms in plankton samples, together with more conventional analyses of sediments and water, were performed for the purpose of investigating the accumulation of heavy metals by plankton in three Canadian Shield lakes polluted with Cu, Zn, Cd, Pb, As, and SO2?4 from a base metal mine and smelter. The results showed

Togwell A. Jackson; Thomas Bistricki

1995-01-01

391

Groups of Galaxies in AEGIS: The 200 ksec Chandra Extended X-ray Source catalogue  

Microsoft Academic Search

We present the discovery of seven X-ray emitting groups of galaxies selected\\u000aas extended X-ray sources in the 200 ksec Chandra coverage of the\\u000aAll-wavelength Extended Groth Strip International Survey (AEGIS). In addition,\\u000awe report on AGN activity associated to these systems. Using the DEEP2 Galaxy\\u000aRedshift Survey coverage, we identify optical counterparts and determine\\u000avelocity dispersions. In particular, we

Tesla E. Jeltema; Brian F. Gerke; Elise S. Laird; Christopher N. A. Willmer; Alison L. Coil; Michael C. Cooper; Marc Davis; Kirpal Nandra; Jeffrey A. Newman

2009-01-01

392

The Suzaku High Resolution X-Ray Spectrometer  

Microsoft Academic Search

The X-Ray Spectrometer (XRS) has been designed to provide the Suzaku Observatory with non-dispersive, high-resolution X-ray spectroscopy. As designed, the instrument covers the energy range 0.3 to 12keV, which encompasses the most diagnostically rich part of the X-ray band. The sensor consists of a 32-channel array of X-ray microcalorimeters, each with an energy resolution of about 6eV. The very low

Richard L. Kelley; Kazuhisa Mitsuda; Christine A. Allen; Petar Arsenovic; Michael D. Audley; Thomas G. Bialas; Kevin R. Boyce; Robert F. Boyle; Susan R. Breon; Gregory V. Brown; Jean Cottam; Michael J. Dipirro; Ryuichi Fujimoto; Tae Furusho; Keith C. Gendreau; Gene G. Gochar; Oscar Gonzalez; Masayuki Hirabayashi; Stephen S. Holt; Hajime Inoue; Manabu Ishida; Yoshitaka Ishisaki; Carol S. Jones; Ritva Keski-Kuha; Caroline A. Kilbourne; Dan McCammon; Umeyo Morita; S. Harvey Moseley; Brent Mott; Katsuhiro Narasaki; Yoshiaki Ogawara; Takaya Ohashi; Naomi Ota; John S. Panek; F. Scott Porter; Aristides Serlemitsos; Peter J. Shirron; Gary A. Sneiderman; Andrew E. Szymkowiak; Yoh Takei; June L. Tveekrem; Stephen M. Volz; Mikio Yamamoto; Noriko Y. Yamasaki

2007-01-01

393

Electromagnetically induced transparency for x-rays.  

SciTech Connect

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s-13s and 1s-13p ({approx}800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 1012 W/cm2. The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.

Buth, C.; Santra, R.; Young, L.; Chemistry

2007-06-22

394

X-ray Free-electron Lasers  

Microsoft Academic Search

We review the present status and properties of X-ray free-electron lasers in operation or under construction in the nanometer and sub-nanometer wavelength range, and the novel possibilities they offer for the study of atomic and molecular processes. We also discuss recent developments in relativistic electron beam physics that give us the possibility of designing a new generation of X-ray free-electron

Claudio Pellegrini; Claudio

2009-01-01

395

Reconstructive colour X-ray diffraction imaging--a novel TEDDI imaging method.  

PubMed

Tomographic Energy-Dispersive Diffraction Imaging (TEDDI) enables a unique non-destructive mapping of the interior of bulk objects, exploiting the full range of X-ray signals (diffraction, fluorescence, scattering, background) recorded. By analogy to optical imaging, a wide variety of features (structure, composition, orientation, strain) dispersed in X-ray wavelengths can be extracted and colour-coded to aid interpretation. The ultimate aim of this approach is to realise real-time high-definition colour X-ray diffraction imaging, on the timescales of seconds, so that one will be able to 'look inside' optically opaque apparatus and unravel the space/time-evolution of the materials chemistry taking place. This will impact strongly on many fields of science but there are currently two barriers to this goal: speed of data acquisition (a 2D scan currently takes minutes to hours) and loss of image definition through spatial distortion of the X-ray sampling volume. Here we present a data-collection scenario and reconstruction routine which overcomes the latter barrier and which has been successfully applied to a phantom test object and to real materials systems such as a carbonating cement block. These procedures are immediately transferable to the promising technology of multi-energy-dispersive-detector-arrays which are planned to deliver the other breakthrough, that of one-two orders of magnitude improvement in data acquisition rates, that will be needed to realise real-time high-definition colour X-ray diffraction imaging. PMID:19684902

Lazzari, Olivier; Jacques, Simon; Sochi, Taha; Barnes, Paul

2009-06-26

396

Imaging of magnetic domains with the X-ray microscope at BESSY using X-ray magnetic circular dichroism  

Microsoft Academic Search

X-ray Magnetic Circular Dichroism (X-MCD), i.e. the change of the absorption of circular polarized X-rays for reversed sample magnetization amounts at the L$_{2,3}$-edges of 3d transition metals up to 50% percent. This can be used to obtain in energy-dispersive X-ray imaging techniques a considerable, element-specific magnetic contrast. On the other hand, with the transmission X-ray microscope (TXM) based on the

P. Fischer; G. Schütz; G. Schmahl; P. Guttmann; D. Raasch

1996-01-01

397

X-Ray Optics.  

National Technical Information Service (NTIS)

A technique has been developed to improve the spatial resolving power of a Type 1 X-ray telescope while reducing its size and weight by an appreciable amount. While X-ray telescopy appears to have little attraction industrially, the same basic optical man...

1969-01-01

398

X-ray Equipment  

Microsoft Academic Search

A method is described of determining the area of a body to be subjected to irradiation by x-rays. A calibrated system of shutters is provided, which is used in conjunction with a source of ordinary light placed in the same position as the source of x-rays. Thus from the image formed by the ordinary light, one can determine the region

Hollstein

1949-01-01

399

X-ray calorimeters  

Microsoft Academic Search

X-ray calorimeter instruments for astrophysics have seen rapid development since they were invented in 1984. The prime instrument on all currently planned X-ray spectroscopic observatories is based on calorimeter technology. This relatively simple detection concept that senses the energy of an incident photon by measuring the temperature rise of an absorber material at very low temperatures can form the basis

F. Scott Porter

2010-01-01

400

Development of a soft x-ray diffractometer for a wideband multilayer grating with a novel layer structure in the 2-4 keV range  

NASA Astrophysics Data System (ADS)

We have been developing a wavelength-dispersive soft x-ray spectrograph covering an energy region of 50-4000 eV to attach to a conventional electron microscope. Observation of soft x-ray emission in the 2-4 keV range needs a multilayer coated grating. In order to evaluate the performance of the optical component in the energy region, a goniometric apparatus has been newly developed and the preliminary performance has been tested using synchrotron radiation.

Imazono, Takashi; Koike, Masato; Kawachi, Tetsuya; Hasegawa, Noboru; Koeda, Masaru; Nagano, Tetsuya; Sasai, Hiroyuki; Oue, Yuki; Yonezawa, Zeno; Kuramoto, Satoshi; Terauchi, Masami; Takahashi, Hideyuki; Handa, Nobuo; Murano, Takanori

2012-07-01

401

Photonic crystals at visible, x-ray, and terahertz frequencies  

NASA Astrophysics Data System (ADS)

Photonic crystals are artificial structures with a periodically varying refractive index. This property allows photonic crystals to control the propagation of photons, making them desirable components for novel photonic devices. Photonic crystals are also termed as "semiconductors of light", since they control the flow of electromagnetic radiation similar to the way electrons are excited in a semiconductor crystal. The scale of periodicity in the refractive index determines the frequency (or wavelength) of the electromagnetic waves that can be manipulated. This thesis presents a detailed analysis of photonic crystals at visible, x-ray, and terahertz frequencies. Self-assembly and spin-coating methods are used to fabricate colloidal photonic crystals at visible frequencies. Their dispersion characteristics are examined through theoretical as well as experimental studies. Based on their peculiar dispersion property called the superprism effect, a sensor that can detect small quantities of chemical substances is designed. A photonic crystal that can manipulate x-rays is fabricated by using crystals of a non-toxic plant virus as templates. Calculations show that these metallized three-dimensional crystals can find utility in x-ray optical systems. Terahertz photonic crystal slabs are fabricated by standard lithographic and etching techniques. In-plane superprism effect and out-of-plane guided resonances are studied by terahertz time-domain spectroscopy, and verified by numerical simulations.

Prasad, Tushar

402

SASE free electron lasers as short wavelength coherent sources. From first results at 100 nm to a 1 Å X-ray laser  

NASA Astrophysics Data System (ADS)

During the last few years free electron lasers (FELs) based on self-amplified spontaneous emission (SASE) have been demonstrated at wavelengths of 12 ?m [CITE], 830 nm [CITE], 530 nm [CITE] and 385 nm [CITE], and around 100 nm [CITE]. Recently, saturation has been observed in the vacuum ultraviolet (VUV) spectral region between 82 nm and 125 nm at the TESLA Test Facility (TTF) at DESY. The radiation pulses have been characterized with respect to pulse energy, statistical fluctuations, angular divergence and spectral distribution, both in the linear gain and in the saturation regime of the FEL [CITE]. The results are in good agreement with theoretical simulations, providing a solid basis for other projects aiming at still shorter wavelengths down to the 0.1 nm range [CITE].

Treusch, R.; Feldhaus, J.

2003-10-01

403

A single-pass free-electron laser for soft x-rays with wavelengths less than or equal to 10 nm  

SciTech Connect

We consider a single-pass FEL amplifier, driven by an rf-linac followed by a damping ring for reduced emittance, for use in generating intense coherent light at wavelengths <10 nm. The dependence of the optical gain on electron beam quality, studied with the 3-D FEL simulation code FELEX, is given and related to the expected power of self-amplified spontaneous emission. Design issues for the damping ring to achieve the required electron beam quality are discussed.

Goldstein, J.C.; Wang, T.F.; Newnam, B.E.; McVey, B.D.

1987-01-01

404

A Galaxy X-Ray Fundamental Plane?  

Microsoft Academic Search

We suggest that the radii and luminosities of the X-ray-emitting halos of elliptical galaxies define a fundamental plane with the star velocity dispersions, as for the corresponding optical observables. Since the X-ray-emitting material usually is at larger radius than the stars, this can be interpreted as additional evidence for a relation between the space distributions of stellar and dark mass,

M. Fukugita; P. J. E. Peebles

1999-01-01

405

Thoracic spine x-ray  

MedlinePLUS

Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... The test is done in a hospital radiology department or in the health care provider's office. You will lie on the x-ray table in different positions. If the x-ray ...

406

X-ray properties of rotation-powered pulsars  

NASA Astrophysics Data System (ADS)

Radiation of most of the known pulsars is powered by the loss of their rotational energy and angular momentum. Thanks to the Chandra and XMM-Newton observatories, X-ray emission has been detected from over 100 rotation-powered pulsars in the last 12 years. I will overview the current results of X-ray observations of rotation-powered pulsars, including the evolution of the X-ray properties, thermal and magnetospheric components of X-ray emission, and connection between the X-ray emission and emission at other wavelengths.

Pavlov, George; Kargaltsev, Oleg

2013-03-01

407

X ray laser  

NASA Astrophysics Data System (ADS)

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

Nilsen, J.

1991-10-01

408

X-ray laser  

DOEpatents

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

Nilsen, J.

1991-10-12

409

Identification of metal residues associated with bit-use on prehistoric horse teeth by scanning electron microscopy with energy dispersive X-ray microanalysis  

Microsoft Academic Search

Our ability to identify evidence of the use of horses for transportation from archaeozoological remains is important for improving our understanding of the role of horses in socioeconomic changes throughout prehistory. When a horse is used with a bit, the bit can come into contact with the anterior (‘front’) surface of the lower second premolar (P2). Here, results of X-ray

Robin Bendrey

2011-01-01

410

The X-ray universe  

NASA Astrophysics Data System (ADS)

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

Tucker, Wallace; Giacconi, Riccardo

411

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

412

X-ray (image)  

MedlinePLUS

... bone) will block most of the x-ray particles, and will appear white. Metal and contrast media (special dye used to highlight areas of the body) will also appear white. Structures containing air will be black and muscle, fat, ...

413

Massively parallel X-ray holography  

NASA Astrophysics Data System (ADS)

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

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

2008-09-01

414

Coherent x-ray lasers for applications  

SciTech Connect

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

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

1990-12-01

415

Wavelengths, transition probabilities, line strengths and oscillator strengths for the K? and K? X-ray transitions in NiXIX through NiXXVII  

NASA Astrophysics Data System (ADS)

Relativistic configuration interaction calculations with the inclusion of Breit interaction, quantum electrodynamics and finite nuclear mass corrections have been carried out in the extended optimal level scheme using multi-configuration Dirac-Fock wavefunctions on the wavelengths, electric dipole transition rates, line strengths and oscillator strengths of nickel. Through the use of the active space method, the calculated values are compared with the other available data on He-like and Be-like nickel and are found to be in very good agreement with them. In this paper we give accurate transition properties from NiXIX through NiXXVII. These data provide reference value for level lifetime, charge state distribution and average charge of nickel plasma.

Hu, F.; Jiang, G.; Hong, W.; Hao, L. H.

2008-10-01

416

Masked deposition techniques for achieving multilayer period variations required for short-wavelength (68-A) soft-x-ray imaging optics.  

PubMed

Practical issues in the development of multilayer coatings for reflective imaging systems operating at ? ? 68 Å are discussed. The 1% bandpass of Ru/B(4) C multilayers at this short wavelength imposes stringent tolerances with which the actual multilayer period variation across the curved surfaces must match the ideal period variation for a 20× demagnifying Schwarzschild objective. New deposition techniques that use masks to correct the period variation across the curved surfaces of each optic have been developed to ensure reflectance over the entire clear aperture. The narrow bandpass together with steep lateralperiod gradients and steeply curved surfaces requires improved metrology for an acceptable period variation to be obtained and the overlap of the reflectance peaks on the two mirrors to be verified. PMID:20856552

Kortright, J B; Gullikson, E M; Denham, P E

1993-12-01

417

High speed replication of submicron features on large areas by X-ray lithography  

Microsoft Academic Search

To achieve the high throughput necessary for a practical X-ray lithographic system, we have devised a new overall approach to X-ray lithography based on the use of X-rays with wavelengths of 4-6 Å rather than the 8.34-Å wavelength used in previous work. The principal advantage of the shorter wavelengths is that they allow a system to have X-ray windows so

D. Maydan; G. A. Coquin; J. R. Maldonado; S. Somekh; D. Y. Lou; G. N. Taylor

1975-01-01

418

X-ray laser  

Microsoft Academic Search

This invention is directed towards a scalable x-ray laser comprising means for providing an active medium of lithium-like atoms or ions, means for producing in the active medium a population of low density ions in an excited intermediate metastable state and a visible or near infrared laser to stimulate x-ray lasing by resonant or non-resonant antistokes Raman process to the

J. D. Daugherty; H. A. Hyman; S. A. Mani

1980-01-01

419

X-ray binaries  

Microsoft Academic Search

The various types and classes of X-ray binary are reviewed high-lighting recent results. The high mass X-ray binaries (HMXRBs) can be used to probe the nature of the mass loss from the OB star in these systems. Absorption measurements through one orbital cycle of the supergiant system X1700-37 are well modelled by a radiation driven wind and also require a

N. E. White

1989-01-01

420

[Development of X-ray excited fluorescence spectrometer].  

PubMed

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

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

2009-08-01

421

Normal incidence x-ray mirror for chemical microanalysis  

DOEpatents

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

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

1987-08-05

422

X-ray Fluorescence Determination of Element Contents in Milk and Dairy Products  

Microsoft Academic Search

The concentrations of minerals (Na, Mg, P, S, Cl, K, and Ca) and trace elements (Mn, Fe, Ni, Cu, Zn, Rb, Sr, and Br) in different\\u000a types of milk, dairy products, and infant formulas have been determined using wavelength-dispersive X-ray fluorescence analysis\\u000a (WDXRF). Freeze-dried samples pressed as tablets of 4 g have been analyzed. Calibrations have been established using both\\u000a plant

Galina V. Pashkova

2009-01-01

423

Structure of the sulfur K x-ray emission spectrum: influence of the oxidation state  

Microsoft Academic Search

The sulfur K x-ray emission was studied in pure sulfur, anhydrite (CaSO4) and sphalerite (ZnS) samples. The ionizations were induced by electron impact and the spectra were recorded with a wavelength dispersive spectrometer. The spectral processing was performed through a methodology based on the optimization of atomic and experimental parameters. Energies and intensities of diagram and satellite lines were determined

P D Pérez; A C Carreras; J C Trincavelli

2012-01-01

424

Diffractive-refractive optics: (+,-,-,+) X-ray crystal monochromator with harmonics separation.  

PubMed

A new kind of two channel-cut crystals X-ray monochromator in dispersive (+,-,-,+) position which spatially separates harmonics is proposed. The diffracting surfaces are oriented so that the diffraction is inclined. Owing to refraction the diffracted beam is sagittally deviated. The deviation depends on wavelength and is much higher for the first harmonics than for higher harmonics. This leads to spatial harmonics separation. The idea is supported by ray-tracing simulation. PMID:21335920

Hrdý, Jaromír; Mikulík, Petr; Oberta, Peter

2011-01-08

425

Fabrication and test of soft X-ray multilayer diffraction gratings.  

NASA Astrophysics Data System (ADS)

Holographic lithography was used to produce a 0.36 ?m spatial period grating on top of a Mo/C layered synthetic microstructure. The pattern was transferred to the multilayer mirror by reactive ion etching. The performance of the device has been evaluated at the Cu L?,? wavelength (1.33 nm). A simple theoretical model explains the main features of the diffraction efficiency of the soft X-ray highly dispersive multilayer mirror.

Berrouane, H.; André, J. M.; Barchewitz, R.; Malek, C. Khan; Ladan, F. R.; Fouchet, S.; Rivoira, R.

1989-07-01

426

X-ray spectra of a complete sample of extragalactic core-dominated radio sources  

NASA Astrophysics Data System (ADS)

We present ROSAT soft X-ray spectra for the members of a complete sample of 13 core-dominated, flat radio spectrum sources. The sample comprises all radio sources from a flux-limited radio catalog (S5GHz greater than 1 Jy; Kuehr et al. 1981) which are north of delta = 70 deg, at galactic latitudes b greater than 10 deg, and have a flat radio spectrum between 1.4 and 5 GHz (alphar less than 0.5; f approximately nu-alpha). The sources have already undergone much study at radio and optical wavelengths and are classified in broad terms as quasars (8 sources) and BL Lac objects (5 sources). We find mean X-ray power-law energy indices of alphax = 0.59 +/- 0.19 for the quasars and 1.36 +/- 0.27 for the BL Lac objects (68% confidence range for two parameters of interest as determined by a maximum likelihood method), supporting earlier Einstein Observatory results for heterogeneous samples of sources (Worrall & Wilkes 1990). A non-zero dispersion on alphax is found for both the quasars and the BL Lac objects. When we incorporate published radio, mm, and optical measurements and compare the X-ray and broad-band spectral indices alphax, alpharx, alphamm,x, and alphaox, the most obvious difference between the quasar and BL Lac subsamples lies within the X-ray band. We have fitted the multi-wavelength data to inhomogeneous synchotron-self-Compton models and find that, for the BL Lac objects with steep X-ray spectra, synchotron emission can account for the radio to soft X-ray measurements, whereas the BL Lac objects with hard X-ray spectra and the quasars require significant Compton emission to model the spectral flattening indicated by alphax less than alphaox.

Brunner, H.; Lamer, G.; Worrall, D. M.; Staubert, R.

1994-07-01

427

High-resolution strain mapping in bulk samples using full-profile analysis of energy dispersive synchrotron X-ray diffraction data  

Microsoft Academic Search

The feasibility of high-resolution strain mapping in bulk samples with both high-spatial and strain resolution is demonstrated using high-energy X-rays between 100 and 300keV on beam line ID15A at the ESRF. This was achieved by using a multiple-peak Pawley-type refinement on the recorded spectra. An asymmetric peak profile was necessary in order to obtain a point-to-point strain uncertainty of 10?5.

A. Steuwer; J. R. Santisteban; M. Turski; P. J. Withers; T. Buslaps

2005-01-01

428

Further radio pulsations from the direction of the NuSTAR 3.76-second X-ray pulsar, and a dispersion measure estimate.  

NASA Astrophysics Data System (ADS)

During continued efforts to detect radio pulsations from the 3.76- second X-ray pulsar discovered with the NuSTAR telescope (ATels #5020, #5027, #5033, #5035, #5040), we have performed a further two observations with the Max Planck Institute for Radio Astronomy (MPIfR) Effelsberg radio telescope at frequencies of 4.85 GHz and 8.35 GHz (observations started 2013-05-04 at 01:11:20 UTC and lasted for ~ 1hr each).

Eatough, Ralph; Karuppusamy, Ramesh; Kramer, Michael; Klein, Bernd; Champion, David; Keane, Evan; Kraus, Alex; Bassa, Cees; Lyne, Andrew; Lazarus, Patrick; Verbiest, Joris; Freire, Paulo; Brunthaler, Andreas; Falcke, Heino; Spitler, Laura; Stappers, Ben

2013-05-01

429

Multiple dispersed phases in a high-strength low-carbon steel: An atom-probe tomographic and synchrotron X-ray diffraction study  

Microsoft Academic Search

The co-precipitation of Cu, MC (where M is any combination of Cr, Mo or Ti) and austenite (face-centered cubic) is characterized for 5 h isochronal aging times by synchrotron X-ray diffraction and three-dimensional atom-probe tomography for a high-strength low-carbon steel, BlastAlloy 160. High number densities, 10²³ m°³, of co-located Cu and MC preciptates were observed. Only small austenite volume percentages

Michael D. Mulholland; David N. Seidman

2009-01-01

430

Holographic rugate structures for x-ray optics applications  

SciTech Connect

A new approach to x-ray optics has been proposed by Physical Optics Corporation (POC) based on single-step holographic fabrication of highly-efficient x-ray diffraction elements. These elements include holographic gratings and mirrors, slanted (non-Snellian) mirrors, uniform and chirped gratings, holographic optical elements (HOEs), lenses and beam splitters, all of which have been investigated in our Phase 1 research program. They have successfully demonstrated the proof of concept of POC's holographic techniques. In our approach, the holographic recording of the interference patterns produced by two (or more) coherent electromagnetic waves is used to create the desired transmission and reflection Bragg holographic structures which can perform various nonconventional operations in the XUV region (soft-x-ray and EUV, from 1 to 100 nm). The proposed XUV high-efficiency holographic structures can be also be applied to more conventional operations such as laser mirroring, collimating, focusing and wavelength dispersion with extremely high resolving power (>10,000,000). Their multi-functional capability makes them competitive to a majority of conventional XUV optical elements including absorptive multi-layers, Fresnel zone-plates, grazing-optics imaging mirrors (and collimators), multi-layer Fabry-Perot resonators, uniform and nonuniform surface gratings and binary optical elements.

Not Available

1987-12-01

431

Spectrometer for lanthanides' K x-ray fluorescence  

SciTech Connect

X-ray fluorescence analysis is a highly useful technique for determining the chemical composition of matter. The present article describes the successful development of a wavelength-dispersive x-ray fluorescence spectrometer for a fairly high-energy range, 30-60 keV, that can contribute to studying lanthanides' K{beta} spectra with high-energy resolution. By combining a new high-energy synchrotron light source and the present spectrometer, it has been demonstrated that the full width at half maximum for lanthanum's K{beta}{sub 1} is 32 eV and that all the peaks in the spectra are fully resolved. This corresponds to an energy resolution E/{delta}E of 1180, which is ten times better than a conventional system based on a Ge detector, which can detect only two peaks, K{beta}{sub 1} and K{beta}{sub 2}, in seven peaks. The present spectrometer can open up a new field in x-ray spectrometry.

Sakurai, Kenji; Mizusawa, Mari; Terada, Yasuko [National Institute for Materials Science, Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Japan Synchrotron Radiation Research Institute, SPring-8, Sayo-gun, Hyogo 679-5198 (Japan)

2007-06-15

432

Principles of X-ray Navigation  

SciTech Connect

X-ray navigation is a new concept in satellite navigation in which orientation, position and time are measured by observing stellar emissions in x-ray wavelengths. X-ray navigation offers the opportunity for a single instrument to be used to measure these parameters autonomously. Furthermore, this concept is not limited to missions in close proximity to the earth. X-ray navigation can be used on a variety of missions from satellites in low earth orbit to spacecraft on interplanetary missions. In 1997 the Unconventional Stellar Aspect Experiment (USA) will be launched as part of the Advanced Research and Global Observation Satellite (ARGOS). USA will provide the first platform for real-time experimentation in the field of x-ray navigation and also serves as an excellent case study for the design and manufacturing of space qualified systems in small, autonomous groups. Current techniques for determining the orientation of a satellite rely on observations of the earth, sun and stars in infrared, visible or ultraviolet wavelengths. It is possible to use x-ray imaging devices to provide arcsecond level measurement of attitude based on star patterns in the x-ray sky. This technique is explored with a simple simulation. Collimated x-ray detectors can be used on spinning satellites to provide a cheap and reliable measure of orientation. This is demonstrated using observations of the Crab Pulsar taken by the high Energy Astronomy Observatory (HEAO-1) in 1977. A single instrument concept is shown to be effective, but dependent on an a priori estimate of the guide star intensity and thus susceptible to errors in that estimate. A star scanner based on a differential measurement from two x-ray detectors eliminates the need for an a priori estimate of the guide star intensity. A first order model and a second order model of the two star scanner concepts are considered. Many of the stars that emit in the x-ray regime are also x-ray pulsars with frequency stability approaching a part in 10{sup 9}. By observing these pulsations, a satellite can keep accurate time autonomously. They have demonstrated the acquisition and tracking of the Crab nebula pulsar by simulating the operation of a phase-locked loop.

Hanson, John Eric; /SLAC

2006-03-17

433

Glass Monocapillary X-ray Optics And Their Applications In X-ray Microscopy  

Microsoft Academic Search

Elliptical, parabolic and Wolter type glass monocapillaries were fabricated for use as x-ray condensers in the energy range of 250 eV to 20 keV. On a routine basis a diameter error of +\\/-0.4 mum and straightness error of 0.8 mum (peak to valley) can be reached. The final test of condensers was performed at-wavelength by imaging the far field x-ray

X. Zeng; M. Feser; E. Huang; A. Lyon; W. Yun

2010-01-01

434

Source Scanning Type X-Ray Grating Spectrometer  

Microsoft Academic Search

A method is proposed for designing an x-ray spectrometer which can scan a limited wavelength region without movement of the concave grating or the electronic counter. Spectrometers widely used in the past have consisted of a fixed x-ray source and a movable counter. This method is to use a fixed counter and a scanning x-ray source to avoid undesirable movement

Masao Sawada; Kenjiro Tsutsumi

1969-01-01

435

Carbon window soft x-ray imaging using multilayer optics  

Microsoft Academic Search

The paper deals with the recent results of the experiments on soft X-ray imaging of various carbon-containing objects: biological samples, artificial carbon fibres, graphite slices, etc. The working wavelength was chosen to be 4.5 nm due to high penetration ability of these soft X-rays in the carbon materials. The experimental set-up included: laser plasma X-ray source (generated with the 2nd

Igor A. Artyukov; Yegor Bugayev; Oleksandr Yu. Devizenko; Ruslan M. Feschenko; Yuri S. Kasyanov; Valeri V. Kondratenko; Svetlana A. Romanova; Sergei V. Saveliev; Franz Schäfers; Torsten Feigl; Yuri A. Uspenski; Alexander V. Vinogradov

2005-01-01

436

Design of soft x-ray multilayer polarizing elements  

Microsoft Academic Search

The status of polarizing optical elements for the soft x-ray range is reviewed. The criteria for optimum polarization of soft x-ray reflective analyzers, transmission polarizers and phase retarders based on multilayer interference structures are presented. Following these principles, soft x-ray polarizing optical elements have been designed. Designs of broad angular and wavelength range reflective analyzers based on a combination of

Hongchang Wang; Zhanshan Wang; Zhongxiang Gu; Shumin Zhang; Wenjuan Wu; Zhong Zhang; Yao Xu; Fengli Wang; Xinbin Cheng; Bei Wang; Shuji Qin; Lingyan Chen

2006-01-01

437

X-ray imaging in the laser-fusion program  

Microsoft Academic Search

The paper discusses a variety of imaging devices applicable for X-ray imaging in laser-fusion programs. It is noted that X-ray imaging may increase the resolution of microscopes by employing short wavelengths to reduce the diameter of the diffraction-produced blur circle. The simplest imaging device is identified as the X-ray pinhole camera which has been used in laser compression studies. High-resolution

G. H. McCall

1977-01-01

438

Review of soft x-ray laser researches and developments  

Microsoft Academic Search

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

Hiroyuki Daido

2002-01-01

439

Telescope for X ray and gamma ray studies in astrophysics  

Microsoft Academic Search

Imaging of x-rays has been achieved by various methods in astrophysics, nuclear physics, medicine, and material science. A new method for imaging x-ray and gamma-ray sources avoids the limitations of previously used imaging devices. Images are formed in optical wavelengths by using mirrors or lenses to reflect and refract the incoming photons. High energy x-ray and gamma-ray photons cannot be

W. D. Weaver; Upendra D. Desai

1993-01-01

440

Extragalactic X-ray surveys of ULXs and AGNs  

Microsoft Academic Search

Extragalactic X-ray studies provide unique opportunities for studying accreting black holes. In particular, they are necessary for studying phenomena not easily selected or observed in other wavelengths. Among these objects, ultraluminous X-ray sources (ULXs) emit the vast majority of their luminosity in the X-ray band and are very faint or confused in other wavebands. Similarly, heavily obscured active galactic nuclei

Lisa M. Winter

2008-01-01

441

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

NASA Astrophysics Data System (ADS)

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

Hirano, Keiichi; Takahashi, Yumiko; Nagamachi, Shinji

2013-11-01

442

High Performance Multilayer X-ray Optics.  

National Technical Information Service (NTIS)

We review the state-of-the-art in multilayer (ML) coatings for high normal incidence reflectivity at soft x-ray wavelengths. In particular, molybdenum-silicon ML and RU-boron carbide ML grown by magnetron sputtering have demonstrated normal incidence refl...

D. G. Stearns R. S. Rosen S. P. Vernon

1992-01-01

443

VUV and Soft X-Ray Projects  

SciTech Connect

We review the state of the art of the VUV-X ray FEL sources and analyze the limit of the relevant technologies and the future perspectives. Possible strategies aimed at developing the design of a road map toward very short wavelengths, very high brilliance and very short pulses are discussed. Within such a framework we report and comment on the proposed devices.

Dattoli, Giuseppe; Renieri, Alberto [ENEA -UTS FIS, Centro Ricerche di Frascati, C.P. 65 - 00044 Frascati, Rome (Italy)

2003-01-24

444

Micro and imaging x-ray analysis by using polycapillary x-ray optics  

NASA Astrophysics Data System (ADS)

We have studied the micro x-ray fluorescence (XRF) and 2D- or 3D-XRF analysis in the laboratory by using polycapillary optics. A confocal 3D micro-XRF instrument was applied for solid/liquid interface analysis. 2D elemental maps of x-ray fluorescence for the solid surface of an Fe plate after Cu was deposited by chemical plating were obtained. The 2D images could be taken in the solution. This result suggests that this 3D micro-XRF method is useful for in-situ monitoring of chemical reactions on solid-liquid interfaces. Furthermore, we have reported a new application of polycapillary x-ray optics. Two independent straight polycapillary optics were arranged between the sample and an x-ray energy dispersive detector. X-ray fluorescence emitted from the sample was collimated by the first capillary, and then it was introduced into the second capillary. By adjusting the angle between two capillary optics, only the x-rays totally reflected on the inner wall of the second capillary could be detected by the x-ray detector. This result suggests that we can use these polycapillary optics for x-ray energy filtering optics.

Tsuji, Kouichi; Nakano, Kazuhiko; Yamaguchi, Makoto; Yonehara, Tasuku

2008-08-01

445

X-Rays for Children  

MedlinePLUS

... for your child, depending on the goal: Bitewing X-rays (also called cavity-detecting X-rays) — These X-rays are used to view the ... called the 6-year molar) has erupted. Periapical X-rays — These are used to view the entire crowns ...

446