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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

2011-08-15

2

Wavelength-dispersive x-ray fluorescence detector  

Microsoft Academic Search

A wavelength-dispersive x-ray fluorescence detector system has been developed that can be used to discriminate fluorescent photon energies for practically any incident flux. The system uses a Kumakhov polycapillary lens to collimate fluorescent photons from a sample. The collimated photons are transmitted to a crystal-counter combination on a stepping motor driven ?–2? stage. The stage diffracts the photon wavelength of

J. P. Kirkland; V. E. Kovantsev; C. M. Dozier; J. V. Gilfrich; W. M. Gibson; Qi-Fan Xiao; K. Umezawa

1995-01-01

3

A multi-crystal wavelength dispersive x-ray spectrometer  

NASA Astrophysics Data System (ADS)

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

2012-07-01

4

A multi-crystal wavelength dispersive x-ray spectrometer  

PubMed Central

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

2012-01-01

5

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

6

A multi-crystal wavelength dispersive x-ray spectrometer.  

PubMed

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

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

2012-07-01

7

DEVELOPMENT OF A WAVELENGTH DISPERSIVE X-RAY FLUORESCENCE SPECTROMETER USING A MULTI-CAPILLARY X-RAY LENS FOR X-RAY DETECTION  

Microsoft Academic Search

We developed a new type of wavelength dispersive X-ray spectrometer with a multi-capillary X-ray lens (MCX). We installed a MCX into the X-ray detection side (ie. the crystal spectrometer side) of a conventional WD-XRF machine (Shimadzu XRF-1800). The MCX collects fluorescent X-rays from a selected sample area of diameter 0.1 mm or less and collimates them into a nearly parallel

Yuji Horino; Yoshiaki Mokuno; Tadashi Narusawa; Shoji Kuwabara; Sumio Shibata; Hiroyoshi Soejima

8

A controlled dispersion parallel wavelength x ray spectrometer for electron microscopy  

Microsoft Academic Search

A new technique is described 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. Neither of the conventional methods, wavelength dispersive (WDS) nor energy dispersive (EDS) based spectrometry, is optimized for low Z

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

1991-01-01

9

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

10

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

11

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

PubMed

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 approximately eV range, by employing a double-crystal geometry is examined. Finally, examples of applications requiring both spatial and spectral resolutions are presented. PMID:20400840

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

2010-05-01

12

Mineralogical effect correction in wavelength dispersive X-ray florescence analysis of pressed powder pellets  

Microsoft Academic Search

Two methods are utilized to correct the influence of the mineralogical effect on the calibration of elements in geological samples when the pressed powder pellet method is used in wavelength dispersive X-ray fluorescence analysis. The first method involves checking of the 2? angle for the analyzed element in each sample to correct peak shift and the second method involves replacing

H. Z. Shan; S. J. Zhuo; R. X. Shen; C. Sheng

2008-01-01

13

Analysis of selected elements in tobacco by wavelength dispersive X-ray fluorescence spectrometry  

Microsoft Academic Search

A rapid method for the determination of 16 elements in tobacco by wavelength dispersive X-ray fluorescence spectrometry has been developed. The method is accurate and precise, and requires only 9 min per sample for quantitation. Sample preparation consists of placing a portion of dried, ground tobacco in a sample cup, and pressing at 25 tons pressure to make a compressed

1988-01-01

14

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

SciTech Connect

During contract # DE-FG02-ER83545, Parallax Research, Inc. developed a High gain, Fast Scan Broad Spectrum Parallel beam Wavelength Dispersive X-ray Spectrometer for use on Scanning Electron Microscopes (SEM). This new spectrometer allows very fast high resolution elemental analysis of samples in an electron microscope. By comparison to previous WDS spectrometers, it can change from one energy position to another very quickly and has an extended range compared to some similar products.

OHara, David

2009-05-08

15

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

16

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

17

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

18

[Mineralogical effect correction for pressed iron ore samples in wavelength dispersive X-ray fluorescence analysis].  

PubMed

The possibility of correcting mineralogical effect for pressed powder pellets of iron ore samples was studied in wavelength dispersive X-ray fluorescence analysis of major and minor elements with 10 Chinese iron ore CRMs. Two methods were applied to reduce the influence of mineralogical effect. The first one is to check 20 angles for every sample before measurement to correct peak shift; another method is replacing peak intensity with peak area of the analytical line to correct the shape distortion of the spectrum. The K factors of the two methods for each element were compared to those from regular measurements. The results show that the calibration for most of the elements was improved, although to different degrees. The improvement in the calibration for sulfur is evident. The calibration for other elements can meet the general requirements except for total iron. PMID:18844184

Shan, Hua-Zhen; Zhuo, Shang-Jun; Sheng, Cheng; Shen, Ru-Xiang

2008-07-01

19

Elemental analysis of white electrical tapes by wavelength dispersive X-ray fluorescence spectrometry.  

PubMed

The aim of this study was to analyze and discriminate electrical tapes using the wavelength dispersive X-ray fluorescence (XRF) spectrometry and statistical techniques. The backings of 46 white electrical tapes were analyzed. A discrimination of 90.4% was performed only by quantitative analysis of major elements (relative ratio of Cl to Ca). Ten distinct groups with a discrimination of 78.9% were yielded only by qualitative analysis of trace elements. Ninety-nine electrical tape pairs which could not be discriminated by major elements were further compared with the characteristics of trace elements. The overall discriminating power of 96.1% was obtained by the combination of quantitative and qualitative analysis. The ability of XRF technique to discriminate different electrical tapes was similar to several well-known methods combined. PMID:24053877

Sun, Zhenwen; Quan, Yangke; Sun, Yuyou

2013-10-10

20

Electron Microprobe Analysis by Wavelength Dispersive X-ray Spectrometry (IAP 2006: Course 12.141) Course Notes  

Microsoft Academic Search

The electron microprobe provides a complete micron-scale quantitative chemical analysis of inorganic solids. The method is nondestructive and utilizes characteristic x-rays excited by an electron beam, incident on a flat surface of the sample. This course provides an introduction to the theory of x-ray microanalysis by wavelength and energy dispersive spectrometry (WDS and EDS), ZAF matrix correction procedures and different

Nilanjan Chatterjee

21

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

Microsoft Academic Search

This paper proposes the application of a monochromatic wavelength dispersive X-ray fluorescence (MWDXRF) technique developed in the X-ray Optical Systems laboratory Inc. The technique measures low-level sulfur (uls) in fuel. Data for ultra low sulfur in diesel were collected and analyzed using the combination of the mentioned technique and the usage of engineering tools as a fastloop array and a

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

2009-01-01

22

DEVELOPMENT, DESIGN, AND OPERATION OF A CASCADE IMPACTOR TO COLLECT AEROSOL SAMPLES FOR WAVELENGTH DISPERSIVE X-RAY FLUORESCENCE ANALYSIS  

EPA Science Inventory

The goal of this research project was to design and construct a particle sizing device that will collect and size source emitted aerosols on 47 mm diameter substrates for subsequent wavelength dispersive x-ray fluorescence analysis. Calibration studies were conducted with a proto...

23

Mineralogical effect correction in wavelength dispersive X-ray florescence analysis of pressed powder pellets  

NASA Astrophysics Data System (ADS)

Two methods are utilized to correct the influence of the mineralogical effect on the calibration of elements in geological samples when the pressed powder pellet method is used in wavelength dispersive X-ray fluorescence analysis. The first method involves checking of the 2? angle for the analyzed element in each sample to correct peak shift and the second method involves replacing the peak intensity with the peak area of the analytical line, so to correct for any shape distortion of the peak. The results were compared with those obtained from the normal method. Major elements in 27 Chinese Certified Reference Materials (CRMs) of rocks, soils and sediments were calibrated with a linear regression curve without theoretical or empirical coefficients. In view of the K values, the calibrations of all 8 elements were improved by the first method and those of 6 elements were improved by the second method. Sulfur calibrations with 4 iron ore CRMs were improved with the use of both methods. The methods have been successfully applied for the analysis of the major elements in limestone ores from different resources of a cement factory.

Shan, H. Z.; Zhuo, S. J.; Shen, R. X.; Sheng, C.

2008-05-01

24

Quick X-Ray Reflectometry in the Simultaneous Multiple Angle-Wavelength Dispersive Mode  

NASA Astrophysics Data System (ADS)

The whole profile of the specular X-ray reflectivity curve was simultaneously and quickly measured with no need to rotate the specimen, the detector or the monochromator crystal. A white synchrotron beam from a bending magnet source is incident on a bent-twisted silicon (111) crystal polychromator that produces a convergent X-ray beam with a continuously varying wavelength (energy) and glancing angle to the specimen surface. This convergent X-ray beam was specularly reflected in the vertical direction by the specimen placed at the focus. The normalized spatial distribution across the beam direction of the reflected beam represents a specular X-ray reflectivity curve because each position along the line recorded on the two dimensional detector surface corresponds to a different momentum transfer. Reflectivity curves from a (001) silicon wafer, a nickel thin film on a silicon substrate, and a water surface were measured with data collection times of 0.001-100 s, 0.01-100 s, and 1.0-1000 s, respectively. The simultaneously covered momentum transfer range was 0.03-0.52 Å-1 for solid specimens and 0-0.41 Å-1 for liquid specimen.

Arakawa, E.; Voegeli, W.; Matsushita, T.; Yano, Y. F.; Hatano, T.

2013-03-01

25

Evaluation on the stability of Hg in ABS disk CRM during measurements by wavelength dispersive X-ray fluorescence spectrometry.  

PubMed

The stability of Hg in an acrylonitrile-butadiene-styrene disk certified reference material (ABS disk CRM, NMIJ CRM 8116-a) during measurements by wavelength dispersion X-ray fluorescence (WD-XRF) analysis was evaluated in this study. The XRF intensities of Hg (L(?)) and Pb (L(?)) as well as the XRF intensity ratios of Hg (L(?))/Pb (L(?)) observed under different X-ray tube current conditions as well as their irradiation time were examined to evaluate the stability of Hg in the ABS disk CRM. The observed XRF intensities and the XRF intensity ratios for up to 32 h of measurements under 80 mA of X-ray tube current condition were constant, even though the surface of the ABS disk CRM was charred by the X-ray irradiation with high current for a long time. Moreover, the measurements on Hg and Pb in the charred disks by an energy dispersive XRF (ED-XRF) spectrometer showed constant XRF intensity ratios of Hg (L(?))/Pb (L(?)). From these results, Hg in the ABS disk CRM was evaluated to be sufficiently stable for XRF analysis. PMID:23149612

Ohata, Masaki; Kidokoro, Toshihiro; Hioki, Akiharu

2012-01-01

26

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

27

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

Microsoft Academic Search

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

David OHara; Eric Lochmer

2003-01-01

28

Determination of chemical composition of siderite in concretions by wavelength-dispersive X-ray spectrometry following selective dissolution.  

PubMed

Determination of chemical composition of siderite (Fe, Me)CO(3) (where Me=Mg, Ca, Mn) present in siderite concretion is developed. An accurate and precise determination of Mg, Ca, Mn and Fe in siderite required complete separation of this mineral from other materials, e.g. calcite, quartz. For this purpose, selective dissolution in acetic acid (HAc) was applied. HAc concentration from 0.1 to 1 mol L(-1) and extraction time from 0.5 to 8h were investigated. In each step of investigation of selective dissolution, the X-ray diffraction measurements (XRD) of the residues was performed and also calcium (complexometric titration) and iron (XRF) in solution were determined. HAc of concentration 0.25 mol L(-1) and extraction time of 2h was adopted for siderite separation because in these conditions the siderite was not dissolved and, simultaneously, calcite was completely dissolved. In the next step, the nondissolved sample was digested in hydrochloric acid. The solution of the separated siderite was pipetted onto membrane filter and Mg, Ca, Mn and Fe were determined by wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry. The calibration was performed using 11 certified reference materials of iron ores. Matrix effects were corrected using empirical coefficient model for intermediate-thickness samples. PMID:19064098

Sitko, Rafa?; Zawisza, Beata; Krzykawski, Tomasz; Malicka, Ewa

2009-01-15

29

Multiple wavelength x-ray monochromators.  

National Technical Information Service (NTIS)

An apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The appara...

P. A. Steinmeyer

1991-01-01

30

Determination of Lead Associated with Airborne Particulate Matter by Flame Atomic Absorption and Wave-Length Dispersive X-Ray Fluorescence Spectrometry  

Microsoft Academic Search

The lead content of airborne particulate matter was determined by flame atomic absorption spectrometry (FAAS) following digestion with a mixture of nitric acid and hydrogen peroxide and also by wave-length dispersive x-ray fluorescence (WDXRF). The extraction procedure was checked by analyzing a standard reference material of airborne particulate matter (NIST, SRM — 1648). It was concluded that lead can quantitatively

S. M. Talebi

1998-01-01

31

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

32

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

PubMed Central

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.

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

2013-01-01

33

Development of wavelength-dispersive soft X-ray emission spectrometers for transmission electron microscopes--an introduction of valence electron spectroscopy for transmission electron microscopy.  

PubMed

Two types of wavelength-dispersive soft X-ray spectrometers, a high-dispersion type and a conventional one, for transmission electron microscopes were constructed. Those spectrometers were used to study the electronic states of valence electrons (bonding electrons). Both spectrometers extended the acceptable energy regions to higher than 2000 eV. The best energy resolution of 0.08 eV was obtained for an Al L-emission spectrum by using the high-dispersion type spectrometer. By using the spectrometer, C K-emission of carbon allotropes, Cu L-emission of Cu(1-x)Zn(x) alloys and Pt M-emission spectra were presented. The FWHM value of 12 eV was obtained for the Pt Malpha-emission peak. The performance of the conventional one was also presented for ZnS and a section specimen of a multilayer device. W-M and Si-K emissions were clearly resolved. Soft X-ray emission spectroscopy based on transmission electron microscopy (TEM) has an advantage for obtaining spectra from a single crystalline specimen with a defined crystal setting. As an example of anisotropic soft X-ray emission, C K-emission spectra of single crystalline graphite with different crystal settings were presented. From the spectra, density of states of pi- and sigma-bondings were separately derived. These results demonstrated a method to analyse the electronic states of valence electrons of materials in the nanometre scale based on TEM. PMID:20371492

Terauchi, Masami; Koike, Masato; Fukushima, Kurio; Kimura, Atsushi

2010-01-01

34

Wavelength-dispersive x-ray fluorescence spectrometric determination of tantalum in columbite-tantalite using TaK? and an LiF 420 analysing crystal  

Microsoft Academic Search

The paper proposes a simple, accurate, precise, and rapid method for determining the high atomic number (Z) major-element,\\u000a tantalum (Z = 73), in the rare mineral, columbite [(Fe,Mn) (Nb,Ta)2O6] — tantalite [(Fe,Mn) (Ta,Nb)2O6], by wavelength-dispersive x-ray fluorescence spectrometry (WDXRFS). The other major-element in columbite-tantalite is the\\u000a lower atomic number niobium (Z = 41). The method uses the characteristic radiation, TaK?,

S. Viswanathan; Anjan Chaki; Yamuna Singh

2010-01-01

35

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

36

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 focusing the separate first and second output x-ray radiation wavelengths into separate focal points. 3 figs.

Steinmeyer, P.A.

1992-11-17

37

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

38

Application of a wavelength-dispersive particle-induced X-ray emission system to chemical speciation of phosphorus and sulfur in lake sediment samples  

NASA Astrophysics Data System (ADS)

The chemical speciation of phosphorus and sulfur in lake sediment was performed by analyzing K? X-ray spectra recorded with a high-resolution wavelength-dispersive particle-induced X-ray emission (WD-PIXE) system. The concentrations of phosphorus and sulfur in the sediment were 2500 and 7000 ppm, respectively. To measure both minor elements in a reasonable measurement time, a 2-MeV proton beam with a high current density (6 nA/mm 2) was used for the chemical speciation. The possible chemical state change caused by the proton irradiation was studied in order to determine the maximal irradiation time without significant change. We found that the chemical states of phosphorus and sulfur were stable under a beam current density of 6 nA/mm 2 and a measurement time of 60 min (phosphorus) and 90 min (sulfur). The chemical states of phosphorus and sulfur were determined to be P 5+ and a mixture of S 2- and S 6+, respectively.

Tada, Tsutomu; Fukuda, Hitoshi; Hasegawa, Jun; Oguri, Yoshiyuki

2010-01-01

39

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

40

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

41

Field-Portable Non-Destructive Analysis of Lithic Archaeological Samples by X-Ray Fluorescence Instrumentation using a Mercury Iodide Detector: Comparison with Wavelength-Dispersive XRF and a Case Study in British Stone Axe Provenancing  

Microsoft Academic Search

Field-portable X-ray fluorescence (PXRF) instrumentation incorporating three radioisotope sources and a mercury (II) iodide detector has been evaluated in the non-destructive quantitative chemical analysis of lithic artefacts of archaeological interest. The method was tested by comparing PXRF analyses of 19 archaeological samples of fine- to medium-grained igneous rocks with laboratory wavelength-dispersive whole-rock XRF analyses of the same samples. Elements determined

Olwen Williams-Thorpe; Philip J. Potts; Peter C. Webb

1999-01-01

42

Evolution of AGN's at X ray Wavelengths.  

National Technical Information Service (NTIS)

The cosmological evolution and the Luminosity Function (LF) of x-ray selected Active Galactic Nuclei (AGN) are discussed. The sample used is extracted from the Einstein Observatory Extended Medium Sensitivity Survey (EMSS) and consists of more than 420 ob...

T. Maccacaro R. Dellaceca I. M. Gioia J. T. Stocke A. Wolter

1992-01-01

43

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

44

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

2012-12-15

45

Point diffraction interferometry at soft x-ray wavelengths  

SciTech Connect

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

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

1993-07-01

46

Polycapillary optics for energy dispersive micro x-ray diffractometry  

NASA Astrophysics Data System (ADS)

Energy dispersive microdiffractometry can be carried out using a microfocus x-ray source coupled to a polycapillary lens, which provides an 8000-fold intensity gain. As result this letter shows the orientation of molybdenum microcrystallites over a square area of 4 mm2 with a spatial resolution of 50 ?m.

Bjeoumikhov, A.; Bjeoumikhova, S.; Langhoff, N.; Wedell, R.

2005-04-01

47

Polycapillary optics for energy dispersive micro x-ray diffractometry  

Microsoft Academic Search

Energy dispersive microdiffractometry can be carried out using a microfocus x-ray source coupled to a polycapillary lens, which provides an 8000-fold intensity gain. As result this letter shows the orientation of molybdenum microcrystallites over a square area of 4 mm2 with a spatial resolution of 50 mum.

A. Bjeoumikhov; S. Bjeoumikhova; N. Langhoff; R. Wedell

2005-01-01

48

Polycapillary optics for energy dispersive micro x-ray diffractometry  

SciTech Connect

Energy dispersive microdiffractometry can be carried out using a microfocus x-ray source coupled to a polycapillary lens, which provides an 8000-fold intensity gain. As result this letter shows the orientation of molybdenum microcrystallites over a square area of 4 mm{sup 2} with a spatial resolution of 50 {mu}m.

Bjeoumikhov, A.; Bjeoumikhova, S.; Langhoff, N.; Wedell, R. [IfG Institut fuer Geraetebau GmbH, 12489 Berlin (Germany); Bundesanstalt fuer Materialforschung und-pruefung, 12205 Berlin (Germany); IfG Institut fuer Geraetebau GmbH, 12489 Berlin (Germany); IAP Institut fuer angewandte Photonik e. V., 12489 Berlin (Germany)

2005-04-04

49

X-ray Fluorescence Analysis of Rare-Earth Atoms in Materials by Use of Ultrashort Wavelength X-rays  

Microsoft Academic Search

A new technique of X-ray fluorescence analysis using ultrashort-wavelength X-rays was tested to obtain the K-series of spectra for rare-earth elements in two different kinds of materials, i.e. powder samples of rare-earth oxides and single crystals of rare-earth hexaborides. This technique utilizes a solid-state detector and multichannel pulse-height analyzer, and satisfies the requirements for quantitative identification in samples containing heavy

Yasuhiko Takahashi; Kazuki Yamamoto; Ken-ichi Ohshima; Ken Yukino; Fujio P. Okamura

1998-01-01

50

Energy-dispersive X-ray-absorption edge spectrometry with spectrum filtration by X-ray mirrors  

NASA Astrophysics Data System (ADS)

A highly sensitive energy-dispersive scheme with a semiconductor spectrometer is proposed for determining impurity concentrations from the X-ray-absorption edge spectra. The optimization of spectrum in a band studied is ensured by sequential reflections of transmitted radiation from X-ray mirrors and by variation of the grazing angle of the analyzed beam. Results of measurements of the X-ray-absorption edge spectra of Fe in dispersed salt samples and W impurity in beryllium plate are presented. It is shown that the problem of deconvolution can be numerically solved by smoothing X-ray-absorption fine-structure oscillations with power functions.

Tur'yanskii, A. G.; Gizha, S. S.; Senkov, V. M.; Savel'ev, S. K.

2014-04-01

51

Energy dispersive x-ray detection of thorium dioxide  

SciTech Connect

Since the recognition of the development of certain malignant neoplasms in association with thorium dioxide (Thorotrast), its presence has been documented by light microscopic appearance and time-consuming autoradiography. Energy dispersive x-ray microanalysis can be used in the rapid documentation of thorium in paraffin-embedded tissues and it is confirmed that thorium is the principal component of the granular deposits described by light microscopy.

Bowen, J.H.; Woodward, B.H.; Mossler, J.A.; Ingram, P.; Shelburne, J.D.

1980-09-01

52

Phase dispersion X-ray imaging of murine soft tissue  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

53

An energy dispersive micro X-ray diffractometer based on a combined system of polycapillary optics  

Microsoft Academic Search

An energy dispersive micro X-ray diffractometer based on a combined system of two polycapillary X-ray lenses is designed. The polycapillary X-ray lens in the excitation channel is either a polycapillary parallel X-ray lens (PPXRL) or a slightly focusing polycapillary X-ray lens (SFPXRL). The polycapillary X-ray lens in the detection channel is a PPXRL. At 6.4keV and 2?=141.5°, the total resolution

Tianxi Sun; Zhiguo Liu; Xunliang Ding

2007-01-01

54

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

NASA Astrophysics Data System (ADS)

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

Mendoza Cuevas, Ariadna; Perez Gravie, Homero

2011-03-01

55

Energy-dispersive X-ray emission spectroscopy using an X-ray free-electron laser in a shot-by-shot mode.  

PubMed

The ultrabright femtosecond X-ray pulses provided by X-ray free-electron lasers open capabilities for studying the structure and dynamics of a wide variety of systems beyond what is possible with synchrotron sources. Recently, this "probe-before-destroy" approach has been demonstrated for atomic structure determination by serial X-ray diffraction of microcrystals. There has been the question whether a similar approach can be extended to probe the local electronic structure by X-ray spectroscopy. To address this, we have carried out femtosecond X-ray emission spectroscopy (XES) at the Linac Coherent Light Source using redox-active Mn complexes. XES probes the charge and spin states as well as the ligand environment, critical for understanding the functional role of redox-active metal sites. K?(1,3) XES spectra of Mn(II) and Mn(2)(III,IV) complexes at room temperature were collected using a wavelength dispersive spectrometer and femtosecond X-ray pulses with an individual dose of up to >100 MGy. The spectra were found in agreement with undamaged spectra collected at low dose using synchrotron radiation. Our results demonstrate that the intact electronic structure of redox active transition metal compounds in different oxidation states can be characterized with this shot-by-shot method. This opens the door for studying the chemical dynamics of metal catalytic sites by following reactions under functional conditions. The technique can be combined with X-ray diffraction to simultaneously obtain the geometric structure of the overall protein and the local chemistry of active metal sites and is expected to prove valuable for understanding the mechanism of important metalloproteins, such as photosystem II. PMID:23129631

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

2012-11-20

56

Energy-dispersive X-ray emission spectroscopy using an X-ray free-electron laser in a shot-by-shot mode  

PubMed Central

The ultrabright femtosecond X-ray pulses provided by X-ray free-electron lasers open capabilities for studying the structure and dynamics of a wide variety of systems beyond what is possible with synchrotron sources. Recently, this “probe-before-destroy” approach has been demonstrated for atomic structure determination by serial X-ray diffraction of microcrystals. There has been the question whether a similar approach can be extended to probe the local electronic structure by X-ray spectroscopy. To address this, we have carried out femtosecond X-ray emission spectroscopy (XES) at the Linac Coherent Light Source using redox-active Mn complexes. XES probes the charge and spin states as well as the ligand environment, critical for understanding the functional role of redox-active metal sites. K?1,3 XES spectra of MnII and Mn2III,IV complexes at room temperature were collected using a wavelength dispersive spectrometer and femtosecond X-ray pulses with an individual dose of up to >100 MGy. The spectra were found in agreement with undamaged spectra collected at low dose using synchrotron radiation. Our results demonstrate that the intact electronic structure of redox active transition metal compounds in different oxidation states can be characterized with this shot-by-shot method. This opens the door for studying the chemical dynamics of metal catalytic sites by following reactions under functional conditions. The technique can be combined with X-ray diffraction to simultaneously obtain the geometric structure of the overall protein and the local chemistry of active metal sites and is expected to prove valuable for understanding the mechanism of important metalloproteins, such as photosystem II.

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

2012-01-01

57

An energy dispersive micro X-ray diffractometer based on a combined system of polycapillary optics  

NASA Astrophysics Data System (ADS)

An energy dispersive micro X-ray diffractometer based on a combined system of two polycapillary X-ray lenses is designed. The polycapillary X-ray lens in the excitation channel is either a polycapillary parallel X-ray lens (PPXRL) or a slightly focusing polycapillary X-ray lens (SFPXRL). The polycapillary X-ray lens in the detection channel is a PPXRL. At 6.4 keV and 2 ? = 141.5°, the total resolution of the diffractometer based on a SFPXRL in the excitation channel and a PPXRL in the detection channel in ? d/ d is 4.8%.

Sun, Tianxi; Liu, Zhiguo; Ding, Xunliang

2007-08-01

58

The evolution of AGN's at x ray wavelengths  

NASA Technical Reports Server (NTRS)

The cosmological evolution and the Luminosity Function (LF) of x-ray selected Active Galactic Nuclei (AGN) are discussed. The sample used is extracted from the Einstein Observatory Extended Medium Sensitivity Survey (EMSS) and consists of more than 420 objects. Preliminary results from the Rosat all sky survey data confirm the correctness of the optical identification of the EMSS sources, thus giving confidence to the results obtained from the analysis of the AGN sample. The XLF observed at different redshifts gives direct evidence of cosmological evolution. Data were analyzed within the framework of luminosity evolution models and the two most common evolutionary forms were considered. Luminosity dependent evolution is required if the evolution function has the exponential form, whereas the simpler pure luminosity evolution model is still acceptable if the evolution function has the power law form. Using the whole sample of objects the number counts and the devolved XLF were derived. A comparison of the EMSS Data with preliminary Rosat results indicates an overall agreement.

Maccacaro, Tommaso; Dellaceca, R.; Gioia, I. M.; Stocke, J. T.; Wolter, A.

1992-01-01

59

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

SciTech Connect

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

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

1988-03-01

60

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

NASA Technical Reports Server (NTRS)

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

Gorenstein, P.

1986-01-01

61

Variable magnification variable dispersion glancing incidence imaging x-ray spectroscopic telescope  

NASA Technical Reports Server (NTRS)

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

Hoover, Richard B. (Inventor)

1991-01-01

62

Variable magnification variable dispersion glancing incidence imaging x ray spectroscopic telescope  

NASA Technical Reports Server (NTRS)

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

Hoover, Richard (inventor)

1990-01-01

63

Transit Observations of the Hot Jupiter HD 189733b at X-Ray Wavelengths  

NASA Astrophysics Data System (ADS)

We present new X-ray observations obtained with Chandra ACIS-S of the HD 189733 system, consisting of a K-type star orbited by a transiting Hot Jupiter and an M-type stellar companion. We report a detection of the planetary transit in soft X-rays with a significantly deeper transit depth than observed in the optical. The X-ray data favor a transit depth of 6%-8%, versus a broadband optical transit depth of 2.41%. While we are able to exclude several possible stellar origins for this deep transit, additional observations will be necessary to fully exclude the possibility that coronal inhomogeneities influence the result. From the available data, we interpret the deep X-ray transit to be caused by a thin outer planetary atmosphere which is transparent at optical wavelengths, but dense enough to be opaque to X-rays. The X-ray radius appears to be larger than the radius observed at far-UV wavelengths, most likely due to high temperatures in the outer atmosphere at which hydrogen is mostly ionized. We furthermore detect the stellar companion HD 189733B in X-rays for the first time with an X-ray luminosity of log LX = 26.67 erg s-1. We show that the magnetic activity level of the companion is at odds with the activity level observed for the planet-hosting primary. The discrepancy may be caused by tidal interaction between the Hot Jupiter and its host star.

Poppenhaeger, K.; Schmitt, J. H. M. M.; Wolk, S. J.

2013-08-01

64

Determination of tungsten in ores by energy dispersive X-ray fluorescence analysis  

Microsoft Academic Search

The possible determination of tungsten in low grade ores from Northern India, Rajasthan State has been explored by energy dispersive X-ray fluorescence analysis \\/EDXRF\\/ technique using radioisotope based excitation of W L X-rays and high resolution Si\\/Li\\/ detector system. Finely powdered ore has been diluted with optimal quantity of cellulose and converted into pellets to make it suitable for X-ray

M. P. Chacharkar; M. D. Sathe; Madan Lal

1987-01-01

65

Characterization of thin graphite layers and graphene by energy dispersive X-ray analysis  

Microsoft Academic Search

Ultrathin graphite and few layer graphene fragments were obtained by mechanical exfoliation on copper surface and characterized by scanning electron microscopy, the energy dispersive X-ray spectroscopy and Raman spectroscopy. In order to achieve higher sensitivity on surface carbon layers the low-energy probing (1keV) by the energy dispersive spectroscopy was used. Data of the energy dispersive X-ray spectroscopy allows to obtain

A. Ilyin; N. Guseinov; A. Nikitin; I. Tsyganov

2010-01-01

66

Chemical analysis of coal by energy dispersive x-ray fluorescence utilizing artificial standards  

Microsoft Academic Search

This chapter describes the use of x-ray fluorescence utilizing the powder method to make accurate determinations of the elemental composition of coal. It reports results of an analysis using an EG and G ORTEC 6110 Energy Dispersive X-ray Spectrometer. It explains that since coal standards are not particularly stable with time and some compositional ranges are not adequately covered, utilization

Wheeler

1982-01-01

67

Variable magnification variable dispersion glancing incidence imaging X ray spectroscopic telescope  

Microsoft Academic Search

A variable magnification variable dispersion glancing incidence x ray spectroscopic telescope capable of multiple high spatial revolution imaging at precise spectral lines of solar and stellar x ray and extreme ultraviolet radiation sources includes a primary optical system which focuses the incoming radiation to a primary focus. Two or more rotatable carriers each providing a different magnification are positioned behind

Richard Hoover

1990-01-01

68

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

69

Automated Energy-Dispersive X-Ray Determination of Trace Elements in Stream Sediments.  

National Technical Information Service (NTIS)

Nickel, copper, tungsten, lead, bismuth, niobium, silver, cadmium, and tin are determined in stream sediments using a computer-controlled energy-dispersive x-ray fluorescence system. The system consists of an automatic 20-position sample changer, a silico...

J. M. Hansel C. J. Martell

1977-01-01

70

Rest-wavelength fiducials for the ITER core imaging x-ray spectrometer.  

PubMed

Absolute wavelength references are needed to derive the plasma velocities from the Doppler shift of a given line emitted by a moving plasma. We show that such reference standards exist for the strongest x-ray line in neonlike W(64+), which has become the line of choice for the ITER (Latin "the way") core imaging x-ray spectrometer. Close-by standards are the Hf L?(3) line and the Ir L?(2) line, which bracket the W(64+) line by ±30 eV; other standards are given by the Ir L?(1) and L?(2) lines and the Hf L?(1) and L?(2) lines, which bracket the W(64+) line by ±40 and ±160 eV, respectively. The reference standards can be produced by an x-ray tube built into the ITER spectrometer. We present spectra of the reference lines obtained with an x-ray microcalorimeter and compare them to spectra of the W(64+) line obtained both with an x-ray microcalorimeter and a crystal spectrometer. PMID:23126933

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

2012-10-01

71

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

72

X-ray characteristics of iridium and platinum blacks of various dispersity  

Microsoft Academic Search

X-ray and structural characteristics of iridium and platinum blacks of various dispersity in the coherent scattering region from 40 to 700 Å have been studied. High dispersity blacks are shown to contain crystalline and X-ray amorphous particles with a disordered structure and decreased coordination number. For such blacks a 0.003 Å increase in the unit cell parameter is observed.

E. M. Moroz; S. V. Bogdanov; V. A. Ushakov

1978-01-01

73

Single photon energy dispersive x-ray diffraction  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

74

Single photon energy dispersive x-ray diffraction.  

PubMed

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

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

2014-03-01

75

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

Microsoft Academic Search

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

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

2010-01-01

76

The X-Ray Wavelength Calibration of the Xmm-Newton Rgs  

Microsoft Academic Search

The X-ray Reflection Grating Spectrometers (RGS) aboard ESA's orbital XMM-newton observatory are currently able to measure wavelengths to an accuracy of about 8mA. It is clear that this is largely determined by systematic errors coming in roughly equal parts from uncertainties in internal geometry and in spacecraft pointing. The statistical error with which the position of an individual line can

Andrew M. Pollock; Jelle S. Kaastra

2003-01-01

77

Multi-wavelength Data Analysis of ONC X-ray Sources  

NASA Astrophysics Data System (ADS)

To take advantage of the increasing amount of available multi-wavelength astronomical data, we are statistically merging data from several wavelength regimes to analyze astronomical objects. This simultaneous analysis of emission across a wide range of wavelengths will help to provide a composite understanding of young stellar objects. A statistical clustering technique coupled with fused multi-wavelength data from the optical, infrared, and X-ray can provide insight into the physical mechanisms responsible for the intense emission from young stars in different wavelength regimes and can be used to view trends and correlations between those regimes. We present some details of the data fusion followed by our results thus far analyzing spectral data from pre-main sequence (PMS) stars in the Orion Nebula Cluster (ONC).

Hojnacki, Susan M.; Grosso, Nicolas; Micela, Giusi; Richards, Donald; Schulz, Norbert; Huenemoerder, David

2010-07-01

78

The X-Ray Wavelength Calibration of the Xmm-Newton Rgs  

NASA Astrophysics Data System (ADS)

The X-ray Reflection Grating Spectrometers (RGS) aboard ESA's orbital XMM-newton observatory are currently able to measure wavelengths to an accuracy of about 8mA. It is clear that this is largely determined by systematic errors coming in roughly equal parts from uncertainties in internal geometry and in spacecraft pointing. The statistical error with which the position of an individual line can be determined is more like 1 or 2mA. This paper describes the efforts to bring the systematic errors under control in order to reduce the wavelength uncertainty to values much nearer the statistical errors.

Pollock, Andrew M.; Kaastra, Jelle S.

79

Standardless energy-dispersive X-ray fluorescence analysis using primary radiation monochromatized with LiF(200) crystal  

NASA Astrophysics Data System (ADS)

Energy-dispersive X-ray fluorescence spectrometer (EDXRF) with primary radiation monochromatized by LiF(200) crystal was developed. In the constructed spectrometer, the radiation from the Ag target X-ray tube operated at 50 kV and 40 mA excites the secondary target (Cu, Se, Zr or Mo). The characteristic radiation (Cu K ?, Se K ?, Zr K ? or Mo K ?) of the target is monochromatized with LiF(200) crystal and excites elements in the analyzed sample. The X-ray spectra are collected by thermoelectrically cooled Si-PIN detector with resolution of 145 eV at 5.9 keV. The pinhole collimator placed in front of the X-ray detector allows reducing size of the analyzed area. Quantitative analysis is performed using standardless fundamental parameters (FP) method. Because sample is excited using highly monochromatized radiation, the calculations are much simpler and analysis error resulting from uncertainty of X-ray tube spectral distribution is completely eliminated. Moreover, EDXRF system allows obtaining very low background and appropriate secondary target can be selected for the best excitation of the determined elements and to avoid overlapping of the analyte peaks with characteristic radiation originating from the secondary target. The FP calculations were verified using several certified reference materials of stainless steel. The spectrometer was used for nondestructive analysis of mono- and polycrystals of selenide spinels of general formula M xN yCr zSe 4 (where M, N are Cu 2+, Zn 2+, Cd 2+, Mn 2+, Ge 2+, Ni 2+, V 3+, Sb 3+, Ga 3+). The results from EDXRF were compared with those obtained by means of the wavelength-dispersive X-ray fluorescence spectrometry (WDXRF).

Sitko, Rafa?; Zawisza, Beata; Malicka, Ewa

2008-11-01

80

Energy dispersive x-ray fluorescence spectrometric determination of trace elements in oil samples  

Microsoft Academic Search

A method is described for the determination of trace elements in petroleum by energy dispersive x-ray fluorescence spectrometry. Minimum sample preparation is required. This is achieved by making small targets and spiking the sample with a solution of Cr and Rh in HâSOâ or organo-Rh in mineral oil. Use of two spiking elements with different x-ray energies facilitates the determination

Hideo. Kubo; Robert. Bernthal; Thomas R. Wildeman

1978-01-01

81

Energy Dispersive X-Ray Spectrometry by Microcalorimetry for the SEM  

Microsoft Academic Search

.  ?Analytical X-ray spectrometry for electron beam instruments has advanced significantly with the development of the microcalorimeter\\u000a energy dispersive X-ray spectrometer (µcal EDS). The µcal EDS operates by measuring the temperature rise when a single photon\\u000a is absorbed in a metal target. A cryoelectronic circuit with electrothermal feedback and a superconducting transition edge\\u000a sensor serves as the thermometer. Spectral resolution approaching

Dale Newbury; David Wollman; Sae Woo Nam; Gene Hilton; Kent Irwin; John Small; John Martinis

2002-01-01

82

Extracting chemical information from single-wavelength X-ray reflectivity data. Chemical information from X-ray reflectivity data  

NASA Astrophysics Data System (ADS)

The possibilities for extracting chemical composition-related information from a singlewavelength X-ray reflectometry experiment are investigated. It is shown that the X-ray absorption of certain elements is sufficient to cause a significant effect on the reflectivity curve, which can be in turn exploited to determine its abundance in the thin film. The limitations are discussed using simulated data and the methodology is applied for the determination of the iodine concentration in iodine-treated thin polyaniline films. More generally the method appears to be very sensitive for the non-destructive determination of the weight percentage of metal nanoparticles in thin polymer films.

Salah, Fethi; Harzallah, Besma; Mérian, Thiphaine; Debarnot, Dominique; Poncin-Epaillard, Fabienne; van der Lee, Arie

2013-04-01

83

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

Microsoft Academic Search

Starting on a laboratory developed portable X-ray fluorescence (PXRF) spectrometer; three different analytical results can be performed: analysis of chemical elements, analysis of major chemical crystalline phase and structural analysis, which represents a contribution to a new, low cost development of portable X-ray analyzer; since these results are respectively obtained with independent equipments for X-ray fluorescence, X-ray diffraction and radiography.

Ariadna Mendoza Cuevas; Homero Perez Gravie

2011-01-01

84

At-wavelength metrology using the X-ray speckle tracking technique: case study of a X-ray compound refractive lens  

NASA Astrophysics Data System (ADS)

The X-ray speckle tracking technique has been established on the Test beamline B16 at Diamond and is being used as a valuable tool for at-wavelength metrology. We show here the possibilities and the achievable performances of the X-ray Speckle Tracking technique for optics characterization: the description is illustrated with the case study of the characterization of a compound refractive lens. This optical element was characterized online using the speckle tracking method with nanoradian accuracy and micrometer spatial resolution. For discussion purpose, the results are compared to the ones obtained under similar conditions using a grating interferometer.

Berujon, S.; Wang, H.; Sawhney, K. J. S.

2013-03-01

85

Phase Determination by Multiple-Wavelength X-ray Diffraction: Crystal Structure of a Basic ``Blue'' Copper Protein from Cucumbers  

NASA Astrophysics Data System (ADS)

A novel x-ray diffraction technique, multiple-wavelength anomalous dispersion (MAD) phasing, has been applied to the de novo determination of an unknown protein structure, that of the ``blue'' copper protein isolated from cucumber seedlings. This method makes use of crystallographic phases determined from measurements made at several wavelengths and has recently been made technically feasible through the use of intense, polychromatic synchrotron radiation together with accurate data collection from multiwire electronic area detectors. In contrast with all of the conventional methods of solving protein structures, which require either multiple isomorphous derivatives or coordinates of a similar structure for molecular replacement, this technique allows direct solution of the classical ``phase problem'' in x-ray crystallography. MAD phase assignment should be particularly useful for determining structures of small to medium-sized metalloproteins for which isomorphous derivatives are difficult or impossible to make. The structure of this particular protein provides new insights into the spectroscopic and redox properties of blue copper proteins, an important class of metalloproteins widely distributed in nature.

Guss, J. Mitchell; Merritt, Ethan A.; Phizackerley, R. Paul; Hedman, Britt; Murata, Mitsuo; Hodgson, Keith O.; Freeman, Hans C.

1988-08-01

86

A semianalytic model to extract differential linear scattering coefficients of breast tissue from energy dispersive x-ray diffraction measurements  

SciTech Connect

The goal of this work is to develop a technique to measure the x-ray diffraction signals of breast biopsy specimens. A biomedical x-ray diffraction technology capable of measuring such signals may prove to be of diagnostic use to the medical field. Energy dispersive x-ray diffraction measurements coupled with a semianalytical model were used to extract the differential linear scattering coefficients [{mu}{sub s}(x)] of breast tissues on absolute scales. The coefficients describe the probabilities of scatter events occurring per unit length of tissue per unit solid angle of detection. They are a function of the momentum transfer argument, x=sin({theta}/2)/{lambda}, where {theta}=scatter angle and {lambda}=incident wavelength. The technique was validated by using a 3 mm diameter 50 kV polychromatic x-ray beam incident on a 5 mm diameter 5 mm thick sample of water. Water was used because good x-ray diffraction data are available in the literature. The scatter profiles from 6 deg. to 15 deg. in increments of 1 deg. were measured with a 3 mmx3 mmx2 mm thick cadmium zinc telluride detector. A 2 mm diameter Pb aperture was placed on top of the detector. The target to detector distance was 29 cm and the duration of each measurement was 10 min. Ensemble averages of the results compare well with the gold standard data of A. H. Narten [''X-ray diffraction data on liquid water in the temperature range 4 deg. C-200 deg. C, ORNL Report No. 4578 (1970)]. An average 7.68% difference for which most of the discrepancies can be attributed to the background noise at low angles was obtained. The preliminary measurements of breast tissue are also encouraging.

LeClair, Robert J.; Boileau, Michel M.; Wang Yinkun [Department of Physics and Astronomy, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario, P3E 2C6 (Canada) and Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario, P3E 2C6 (Canada); Department of Physics and Astronomy, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario, P3E 2C6 (Canada); Department of Physics and Astronomy, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario, P3E 2C6 (Canada)

2006-04-15

87

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

88

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

NASA Astrophysics Data System (ADS)

The quantum efficiency is measured 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, detectors with fluffy CsI semitransparent photocathodes are more efficient than those with opaque photocathodes of solid CsI, but the opposite is true at longer wavelengths. Fluffy CsI semitransparent photocathodes with surface densities between 150 and 400 micrograms/sq cm are optimum at soft X-ray wavelengths, and efficiencies of 35 and 41 percent at 8 and 44 A, respectively, were obtained for a single-layer photocathode. The measured peak efficiency for an opaque layer or solid CsI, deposited at 0 deg coating angle and 5000 A (226 micrograms/sq cm) in thickness, is 56 percent at 110 A.

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

1986-07-01

89

X-ray backlighting characterization experiments performed with laser wavelengths of 1. 06, 0. 53, and 0. 35. mu. m  

SciTech Connect

We report the conversion efficiency, xi/sub x/, for production of x-ray backlighting line sources from 1.4 keV to 8.6 keV as a function of laser wavelength, -pulselength and intensity. For K-shell x-ray line emission we observed only a moderate increase in xi/sub x/ when using a 0.35..mu..m (instead of 1.06 ..mu..m) wavelength laser.

Matthews, D.L.; Campbell, E.M.; Ceglio, N.

1982-01-01

90

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

PubMed

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 standard aqueous solutions were used for the quantification of the elements. The present developments concentrate on increasing the convergence between the tissue samples and the calibration models, therefore improving accuracy. For this purpose the composition of the samples in terms of adipose and fibrous tissue was evaluated, using an energy dispersive x-ray diffraction (EDXRD) system. The relationships between the attenuation and scatter properties of the two tissue components and water were determined through Monte Carlo simulations. The results from the simulations and the EDXRD measurements allowed the XRF data from each specimen to be corrected according to its composition. The statistical analysis of the elemental concentrations of the different groups of specimens reveals that all four elements are found in elevated levels in the tumour specimens. The increase is less pronounced for iron and copper and most for potassium and zinc. Other observed features include the substantial degree of inhomogeneity of elemental distributions within the volume of the specimens, varying between 4% and 36% of the mean, depending on the element and the type of the sample. The accuracy of the technique, based on the measurement of a standard reference material, proved to be between 3% and 22% depending on the element, which presents only a marginal improvement (1%-3%) compared to the accuracy of the previously reported results. The measurement precision was between 1% and 9% while the calculated uncertainties on the final elemental concentrations ranged between 10% and 16%. PMID:14971775

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

2004-01-01

91

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

NASA Astrophysics Data System (ADS)

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 standard aqueous solutions were used for the quantification of the elements. The present developments concentrate on increasing the convergence between the tissue samples and the calibration models, therefore improving accuracy. For this purpose the composition of the samples in terms of adipose and fibrous tissue was evaluated, using an energy dispersive x-ray diffraction (EDXRD) system. The relationships between the attenuation and scatter properties of the two tissue components and water were determined through Monte Carlo simulations. The results from the simulations and the EDXRD measurements allowed the XRF data from each specimen to be corrected according to its composition. The statistical analysis of the elemental concentrations of the different groups of specimens reveals that all four elements are found in elevated levels in the tumour specimens. The increase is less pronounced for iron and copper and most for potassium and zinc. Other observed features include the substantial degree of inhomogeneity of elemental distributions within the volume of the specimens, varying between 4% and 36% of the mean, depending on the element and the type of the sample. The accuracy of the technique, based on the measurement of a standard reference material, proved to be between 3% and 22% depending on the element, which presents only a marginal improvement (1%-3%) compared to the accuracy of the previously reported results. The measurement precision was between 1% and 9% while the calculated uncertainties on the final elemental concentrations ranged between 10% and 16%.

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

2004-01-01

92

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

Microsoft Academic Search

The use of both conventional fixed-anode X-ray sources and synchrotron radiation to carry out energy-dispersive X-ray diffraction experiments at high pressure in a diamond anvil cell, is discussed. The photon flux at the sample and at the detector for the two cases are compared and the results are presented in graphs. It is shown that synchrotron radiation experiments can be

Ian L. Spain; David R. Black

1985-01-01

93

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

SciTech Connect

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

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

2010-06-23

94

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

95

Detector arrays for photometric measurements at soft X-ray, ultraviolet and visible wavelengths  

NASA Technical Reports Server (NTRS)

The construction and modes of operation of the Multi-Anode Microchannel Array (MAMA) detectors are described, and the designs of spectrometers utilizing them are outlined. MAMA consists of a curved microchannel array plate, an opaque photocathode (peak quantum efficiency of 19% at 1216 A), and a multi-anode (either discrete- or coincidence-anode) readout array. Designed for use in instruments on spaceborne telescopes, MAMA can be operated in a windowless configuration in extreme-ultraviolet and soft X-ray wavelengths, or in a sealed configuration at UV and visible wavelengths. Advantages of MAMA include low applied potential (less than 3.0 kV), high gain (greater than 10 to the 6th electrons/pulse), low sensitivity to high-energy charged particles, and immunity to external magnetic fields of less than 500 Gauss

Timothy, J. G.; Mount, G. H.; Bybee, R. L.

1979-01-01

96

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

NASA Astrophysics Data System (ADS)

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

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

97

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

98

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

99

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

National Technical Information Service (NTIS)

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

W. F. Sherman D. Haeusermann

1987-01-01

100

Rietveld analysis for energy dispersive x-ray diffraction under high pressure with synchrotron radiation  

Microsoft Academic Search

A new program has been developed for the conversion of energy-dispersive x-ray diffraction spectra obtained from powder samples at high pressure in a diamond anvil cell (DAC) into conventional pseudo angle-dispersive data. The program is compatible with a conventional Rietveld program. This allows the determination of the structural parameters of the samples investigated. Results of a synchrotron radiation study of

H. W. Neuling; W. B. Holzapfel

1992-01-01

101

Improvement of Energy Dispersive X-Ray Fluorescence Throughput: Influence of Measuring Times and Number of Replicates on Validation Performance Characteristics  

Microsoft Academic Search

The mineral nutrients Na, Mg, P, Cl, K, Ca, Fe, and Zn are commonly quantified by X-ray fluorescence energy dispersive (EDXRF)\\u000a and wavelength dispersive systems in food matrices such as milk- and cereal-based powders in order to ensure their quality\\u000a control. In order to optimize EDXRF use on production sites as well as in research and development laboratories, the influence

Loïc Perring; Florence Monard

2010-01-01

102

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

103

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

2010-01-01

104

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

NASA Astrophysics Data System (ADS)

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 the diffraction by crystalline material from a continuous background. Tested on real data (graphite and NaCl), our algorithm achieved to detect diffraction peaks with a good precision (about 1 keV depending on the peak position) even at high energy where very few photons were measured.

Soulez, Ferréol; Crespy, Charles; Kaftandjian, Valérie; Duvauchelle, Philippe

2011-10-01

105

Material specific X-ray imaging using an energy-dispersive pixel detector  

NASA Astrophysics Data System (ADS)

By imaging the X-ray spectral properties or ‘colours’ we have shown how material specific imaging can be performed. Using a pixelated energy-dispersive X-ray detector we record the absorbed and emitted hard X-radiation and measure the energy (colour) and intensity of the photons. Using this technology, we are not only able to obtain attenuation contrast but also to image chemical (elemental) variations inside objects, potentially opening up a very wide range of applications from materials science to medical diagnostics.

Egan, Christopher K.; Wilson, Matthew D.; Veale, Matthew C.; Seller, Paul; Jacques, Simon D. M.; Cernik, Robert J.

2014-04-01

106

Multi-wavelength observations of compact jets in a neutron star X-ray binary  

NASA Astrophysics Data System (ADS)

Our cycle-2 Spitzer IRAC observations revealed the first spectral evidence for compact jets in low-luminosity neutron star (NS) X-ray binary, and furthermore, the optically thin (`break') part of its synchrotron spectrum in 4U~0614+091. As a follow-up of this major result, we ask for simultaneous IRAC and VLA observations of 4U~0614+091 together with quasi-simultaneous MIPS observations at 24um. These multi-wavelength coverage, will give us the first complete broadband spectrum of a compact jet in a low-luminosity NS system. Low-luminosity NSs are important especially because they are the best candidate for a direct comparison of the disc/jet properties in BHs. We will measure observable jet parameters never measured before together in a NS system (e.g. the spectral index in the optically thick and optically thin part of the spectrum, and the break frequency), we will have a precise estimate of the power in the jet and, together with available simultaneous X-rays observations, we will assess the efficiency of the jet production, estimating the fraction of the accreted power that is channeled into the jet.

Migliari, Simone; Fender, Rob; Gallo, Elena; Jonker, Peter; Maccarone, Thomas; Nelemans, Gijs; Tomsick, John

2006-05-01

107

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

108

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

NASA Astrophysics Data System (ADS)

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

Sandberg, Richard Lunt

109

High-resolution detectors for imaging and spectroscopy at ultraviolet and soft X-ray wavelengths  

NASA Technical Reports Server (NTRS)

The Multi-Anode Microchannel Arrays (MAMAs) are a family of pulse-counting imaging array detectors designed specifically for astrophysical investigations in space. The MAMAs have a number of unique performance characteristics which make them particularly suitable for imaging and spectroscopy at ultraviolet and soft X-ray wavelengths. First, they employ 'solar blind' photocathodes eliminating the 'red leak' problem associated with solid state arrays such as the CCDs. Second, they operate with zero readout noise, yielding photon-statistics limited signals. Third, they utilize a random readout technique and can determine both the location of a detected photon and also its arrival time to an accuracy of the order of 100 ns. This paper gives an overview of the construction, mode of operation, and performance characteristics of the MAMA detectors and describes the current status of the development program.

Timothy, J. G.; Morgan, J. S.; Slater, D. C.

1988-01-01

110

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

111

Energy-dispersive X-ray fluorescence spectrometer for analysis of conventional and micro-samples: Preliminary assessment  

NASA Astrophysics Data System (ADS)

The energy-dispersive X-ray fluorescence spectrometer for analysis of conventional and micro-samples using pinhole collimators of various sizes is developed. The measurements can be performed in the air or, in order to decrease the absorption of long-wavelength radiation of low-Z elements, in helium atmosphere. The sample is excited by the air-cooled Rh target X-ray tube of ca. 100 ?m nominal focal spot size and maximum power 75 W. The X-ray spectra of the samples are collected by thermoelectrically cooled Si-PIN detector. The tungsten pinhole collimators of the size holes from 50 to 2000 ?m are placed between primary filter and analyzed sample to reduce size of analyzed area. The sample can be moved using the X- Y stage. The position of the sample is monitored by CCD camera and two laser pointers. The beam spot sizes for various collimators are evaluated by the thin-wire and knife-edge methods. Beside the beam spot sizes, the loss of radiation intensity and the changes of spectral distribution of the incident radiation caused by applying various collimators are also investigated. The sample-surface-down geometry in the designed spectrometer allows for a simple analysis of various samples: solutions, loose powders, solid samples of conventional size and micro-samples.

Sitko, Rafa?; Zawisza, Beata; Malicka, Ewa

2009-05-01

112

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

113

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

SciTech Connect

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 10{sup 5} resolving power.

Warwick, Tony; Padmore, Howard; Voronov, Dmitriy; Yashchuk, Valeriy [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA94720 (United States)

2010-06-23

114

The ChIcAGO Survey: Multi-wavelength Identification of Galactic Plane X-ray Sources  

NASA Astrophysics Data System (ADS)

I present the Chasing the Identification of ASCA Galactic Objects (ChIcAGO) survey, which is designed to identify the unknown X-ray sources discovered during the ASCA Galactic Plane Survey (AGPS). Little is known about most of the AGPS sources, especially those that emit primarily in hard X-rays (2-10 keV) within the F_ 10^-13 to 10^-11 erg cm^-2s^-1 X-ray flux range. In ChIcAGO, the subarcsecond localization capabilities of Chandra have been combined with a multi-wavelength follow-up program, with the ultimate goal of classifying the unidentified sources in the AGPS. Overall to date, 93 unidentified AGPS sources have been observed with Chandra as part of the ChIcAGO survey. A total of 253 X-ray point sources have been detected in these Chandra observations within 3' of the original ASCA positions, the majority of which have optical and infrared counterparts. Using these multi-wavelength follow-up results I have developed a new statistical diagnostic for identifying likely populations of X-ray emitting sources. These studies have revealed that the primary populations of Galactic plane X-ray sources that emit in the F_ 10^-13 to 10^-11 erg cm^-2s^-1 flux range are active stellar coronae, massive stars that are possibly in colliding-wind binaries, X-ray binaries, and magnetars. There is also another primary population that is still unidentified but, on the basis of its X-ray and infrared properties, likely comprise partly of Galactic sources and partly AGN.

Anderson, Gemma; Gaensler, Bryan M.; Slane, Patrick O.; Kaplan, David L.A.; Posselt, Bettina

2014-08-01

115

Two-dimensional energy dispersive x-ray diffraction at high pressures and temperatures  

Microsoft Academic Search

Diffraction studies at extreme pressure-temperature conditions encounter intrinsic difficulties due to the small access angle of the diamond anvil cell and the high background of the diffraction peaks. Energy-dispersive x-ray diffraction is ideal for overcoming these difficulties and allows the collection and display of diffracted signals on the order of seconds, but is limited to one-dimensional information. Materials at high

Yanzhang Ma; Ho-Kwang Mao; Russell J. Hemley; Stephen A. Gramsch; Guoyin Shen; Maddury Somayazulu

2001-01-01

116

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

117

Analysis of some Nigerian solid mineral ores by energy-dispersive X-ray fluorescence spectroscopy  

Microsoft Academic Search

Determination of major, minor and trace elements in some Nigerian solid mineral ores by energy-dispersive X-ray fluorescence (EDXRF) spectroscopy is described. Concentration values of major, minor and trace elements for Z>18 are reported. The mineral ores studied include (i) tantalite–coloumbite minerals, (ii) bismuth minerals and (iii) lead minerals. The accuracy and precision of the technique for chemical analysis was assured

E. I. Obiajunwa

2001-01-01

118

Use of energy-dispersive x-ray fluorescence analysis in clay mineral ion exchange studies  

Microsoft Academic Search

A rapid, reliable, semiquantitative method for following ion exchange processes in clay minerals is described. An energy-dispersive x-ray fluorescence technique is used. The completeness of the exchange process for the clay mineral montmorillonite was investigated for the ions Rb\\/sup +1\\/, Sr\\/sup +2\\/, and Y\\/sup +3\\/. Samples of clay, suspended on asbestos, were packed in an ion exchange column and solutions

J. F. Mucci; R. L. Stearns

1977-01-01

119

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

Microsoft Academic Search

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

Yueh-Hsiang Chen

120

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

Microsoft Academic Search

The use of mercuric iodide arrays for energy-dispersive X-ray diffraction (EDXRD) spectroscopy is now being investigated by us 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 HgI2 detectors: operate at or

J. S. Iwanczyk; B. E. Patt; Y. J. Wang; M. Croft; Z. Kalmar; W. Mayo

1995-01-01

121

Energy dispersive X-Ray fluorescence determination of thorium in phosphoric acid solutions  

Microsoft Academic Search

Energy dispersive X-ray fluorescence studies on determination of thorium (in the range of 7 to 137mg\\/mL) in phosphoric acid solutions obtained by dissolution of thoria in autoclave were made. Fixed amounts of Y internal standard solutions, after dilution with equal amount of phosphoric acid, were added to the calibration as well as sample solutions. Solution aliquots of approximately 2–5µL were

N. N. Mirashi; Sangita Dhara; S. Sanjay Kumar; Satyajeet Chaudhury; N. L. Misra; S. K. Aggarwal

2010-01-01

122

Combination of Raman, Infrared, and X-Ray Energy-Dispersion Spectroscopies and X-Ray Diffraction to Study a Fossilization Process  

NASA Astrophysics Data System (ADS)

X-ray diffraction was combined with X-ray energy-dispersion, Fourier-transform infrared, and Raman spectroscopies to study the fossilization of a Cretaceous specimen of the plant Brachyphyllum castilhoi, a fossil from the Ipubi Formation, in the Araripe Sedimentary Basin, Northeastern Brazil. Among the possible fossilization processes, which could involve pyrite, silicon oxide, calcium oxide, or other minerals, we were able to single out pyritization as the central mechanism producing the fossil, more than 100 million years ago. In addition to expanding the knowledge of the Ipubi Formation, this study shows that, when combined with other experimental techniques, Raman spectroscopy is a valuable tool at the paleontologist's disposal.

de Sousa Filho, Francisco Eduardo; da Silva, João Hermínio; Feitosa Saraiva, Antônio Álamo; Brito, Deyvid Dennys S.; Viana, Bartolomeu Cruz; de Oliveira Abagaro, Bruno Tavares; de Tarso Cavalcante Freire, Paulo

2011-12-01

123

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

124

High Performance Non-Dispersive X-Ray Spectrometers for Charge Exchange Measurements  

NASA Technical Reports Server (NTRS)

Currently, the only measurements of cosmological charge exchange have been made using low resolution, non-dispersive spectrometers like the PSPC on ROSAT and the CCD instruments on Chandra and XMM/Newton. However, upcoming cryogenic spectrometers on Astro-H and IXO will add vast new capabilities to investigate charge exchange in local objects such as comets and planetary atmospheres. They may also allow us to observe charge exchange in extra-solar objects such as galactic supernova remnants. With low spectral resolution instruments such as CCDs, x-ray emission due to charge exchange recombination really only provides information on the acceptor species, such as the solar wind. With the new breed of x-ray calorimeter instruments, emission from charge exchange becomes highly diagnostic allowing one to uniquely determine the acceptor species, ionization state, donor species and ionization state, and the relative velocity of the interaction. We will describe x-ray calorimeter instrumentation and its potential for charge exchange measurements in the near term. We will also touch on the instrumentation behind a decade of high resolution measurements of charge exchange using an x-ray calorimeter at the Lawrence Livermore National Laboratory.

Porter Frederick; Adams, J.; Beiersdorfer, P.; Brown, G. V.; Karkatoua, D.; Kelley, R. L.; Kilbourne, C. A.; Lautenagger, M.

2010-01-01

125

EXTENDED X-RAY EMISSION FINE STRUCTURE (EXEFS) AND X-RAY ABSORPTION NEAR EDGE STRUCTURE (XANES) OF SOIL SAMPLES  

Microsoft Academic Search

Silicon K X-ray fluorescence spectra of soil samples in a volcano island are measured using a commercially available wavelength dispersive X-ray fluorescence spectrometer for elemental analysis. EXEFS (extended X-ray emission fine structure) are found at the low energy side of the K X-ray fluorescence diagram lines. Synchrotron radiation XANES (X-ray absorption near edge structure) spectra are measured for the same

Jun Kawai; Susumu Tohno

2001-01-01

126

Femtosecond time-resolved X-ray absorption spectroscopy of liquid using a hard X-ray free electron laser in a dual-beam dispersive detection method.  

PubMed

We present femtosecond time-resolved X-ray absorption spectroscopy of aqueous solution using a hard x-ray free electron laser (SACLA) and a synchronized Ti:sapphire laser. The instrumental response time is 200 fs, and the repetition rate of measurement is 10 Hz. A cylindrical liquid beam 100 ?m in diameter of aqueous ammonium iron(III) oxalate solution is photoexcited at 400 nm, and the transient X-ray absorption spectra are measured in the K-edge region of iron, 7.10 - 7.26 keV, using a dual X-ray beam dispersive detection method. Each of the dual beams has the pulse energy of 1.4 ?J, and pump-induced absorbance change on the order of 10(-3) is successfully detected. The photoexcited iron complex exhibits a red shifted iron K-edge with the appearance time constant of 260 fs. The X-ray absorption difference spectra, with and without the pump pulses, are independent of time delay after 1.5 ps up to 100 ps, indicating that the photoexcited species is long-lived. PMID:24515070

Obara, Yuki; Katayama, Tetsuo; Ogi, Yoshihiro; Suzuki, Takayuki; Kurahashi, Naoya; Karashima, Shutaro; Chiba, Yuhei; Isokawa, Yusuke; Togashi, Tadashi; Inubushi, Yuichi; Yabashi, Makina; Suzuki, Toshinori; Misawa, Kazuhiko

2014-01-13

127

Dispersion Relation of an OH-Stretching Vibration from Inelastic X-Ray Scattering.  

PubMed

We show that recent advances now allow us to measure the wave vector dependence of OH-stretching frequencies at energies around 400 meV by inelastic x-ray scattering using ID28@ESRF. We found a large, unexpected dispersion when we measured the dispersion relations of the hydrogen stretching frequencies of diaspore, alpha-AlOOH, where the hydrogen atoms participate in a hydrogen bond of intermediate strength. We can account for this behavior with density functional perturbation theory calculations and a simple model based on H-H interactions. PMID:18764470

Winkler, Björn; Friedrich, Alexandra; Wilson, Dan J; Haussühl, Eiken; Krisch, Michael; Bosak, Alexei; Refson, Keith; Milman, Victor

2008-08-01

128

Semi-quantitative analysis of changes in soil coatings by scanning electron microscope and energy dispersive X-ray mapping  

Microsoft Academic Search

Scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDX) has been used extensively with soils and sediments. The method of obtaining X-ray spectrums at single points on samples has two shortcomings; (1) it is limited to a particular point and (2) it is primarily a qualitative measure indicating the presence or the absence of specific elements. The relative

Bashar M Alsmadi; Peter Fox

2001-01-01

129

The Determination of the Efficiency of Energy Dispersive X-Ray Spectrometers by a New Reference Material  

Microsoft Academic Search

A calibration procedure for the detection efficiency of energy dispersive X-ray spectrometers (EDS) used in combination with scanning electron microscopy (SEM) for standardless electron probe microanalysis (EPMA) is presented. The procedure is based on the comparison of X-ray spectra from a reference material (RM) measured with the EDS to be calibrated and a reference EDS. The RM is certified by

Marco Alvisi; Markus Blome; Michael Griepentrog; Vasile-Dan Hodoroaba; Peter Karduck; Marco Mostert; Michele Nacucchi; Mathias Procop; Martin Rohde; Frank Scholze; Peter Statham; Ralf Terborg; Jean-Francois Thiot

2006-01-01

130

Photon Counting Energy Dispersive Detector Arrays for X-ray Imaging  

PubMed Central

The development of an innovative detector technology for photon-counting in X-ray imaging is reported. This new generation of detectors, based on pixellated cadmium telluride (CdTe) and cadmium zinc telluride (CZT) detector arrays electrically connected to application specific integrated circuits (ASICs) for readout, will produce fast and highly efficient photon-counting and energy-dispersive X-ray imaging. There are a number of applications that can greatly benefit from these novel imagers including mammography, planar radiography, and computed tomography (CT). Systems based on this new detector technology can provide compositional analysis of tissue through spectroscopic X-ray imaging, significantly improve overall image quality, and may significantly reduce X-ray dose to the patient. A very high X-ray flux is utilized in many of these applications. For example, CT scanners can produce ~100 Mphotons/mm2/s in the unattenuated beam. High flux is required in order to collect sufficient photon statistics in the measurement of the transmitted flux (attenuated beam) during the very short time frame of a CT scan. This high count rate combined with a need for high detection efficiency requires the development of detector structures that can provide a response signal much faster than the transit time of carriers over the whole detector thickness. We have developed CdTe and CZT detector array structures which are 3 mm thick with 16×16 pixels and a 1 mm pixel pitch. These structures, in the two different implementations presented here, utilize either a small pixel effect or a drift phenomenon. An energy resolution of 4.75% at 122 keV has been obtained with a 30 ns peaking time using discrete electronics and a 57Co source. An output rate of 6×106 counts per second per individual pixel has been obtained with our ASIC readout electronics and a clinical CT X-ray tube. Additionally, the first clinical CT images, taken with several of our prototype photon-counting and energy-dispersive detector modules, are shown.

Iwanczyk, Jan S.; Nygard, Einar; Meirav, Oded; Arenson, Jerry; Barber, William C.; Hartsough, Neal E.; Malakhov, Nail; Wessel, Jan C.

2009-01-01

131

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

SciTech Connect

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

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

2013-09-10

132

Energy Dispersive X ray Fluorescence with Graphite Monochromator - Uranium and Plutonium Analyses in Aqueous or Organic Media.  

National Technical Information Service (NTIS)

We describe an energy dispersive X ray fluorescence apparatus equipped with a cylinder graphite monochromator developed in our laboratory. The graphite monochromator is inserted between the sample and the detector, it permits the selection of the fluoresc...

T. Berthoud N. Delorme P. Delorme M. Iaremenko

1989-01-01

133

High-energy processes in low-mass protostars - an X-ray to radio multi-wavelength perspective  

NASA Astrophysics Data System (ADS)

High-energy processes in protostars remain poorly understood. Only after the recently finished Chandra Orion Ultra-deep Project (COUP), statistically significant information on X-ray emission from Young Stellar Objects (YSOs) has been obtained. For an understanding of the mechanisms responsible for the X-ray emission, multi-wavelength correlations of flares, especially in the radio regime, are necessary and have become an active field of research. Magnetic fields cause several high-energy phenomena in the coronae of YSOs mainly due to magnetic reconnection which are observable in a wide wavelength range from nonthermal centimetric radio emission to X-rays. In this work, these processes were probed using a variety of very different methods which can be grouped into three major topics: X-ray to radio multi-wavelength variability of Young Stellar Objects - The Coronet cluster in the nearby R~CrA dark cloud offers the rare opportunity to study a compact cluster of several very young protostars which are detected at radio- and X-ray wavelengths. Initially, a study focusing separately on X-ray and radio variability of these sources was conducted. Subsequently, in August 2005, the same region was studied in the first simultaneous X-ray, radio, near-infrared, and optical monitoring campaign of YSOs. Several observatories were observing simultaneously, namely the Chandra X-ray Observatory, the VLA, as well as telescopes with optical and near-infrared detectors in Chile and South Africa. Remarkable intra-band variability but no clearly correlated variability was found. This most importantly suggests that there is no direct link between the X-ray and optical/infrared emission and supports the notion that accretion is not an important source for the X-ray emission of these YSOs. Combining the Chandra X-ray data collected in the course of the multi-wavelength campaign with previous archival data, one of the deepest X-ray datasets ever obtained of a star-forming region is obtained and discussed. Radio emission from protostars - Looking for compact nonthermal centimetric radio emission, high-sensitivity Very-Long-Baseline Interferometry (VLBI) observations of four nearby protostars were carried out, yielding the currently most sensitive data of such sources. Weak compact emission was found in the VLBI data of the class~0/I binary YLW15 VLA2, constraining the size of its corona to sub-AU scales. Since this source is part of a binary system with observed orbital motion, further VLBI observations will allow to quickly determine the orbit very accurately. The observed sources apparently were showing quiescent radio emission on the larger scales probed by the Very Large Array (VLA). Until now, only very few radio flares of YSOs have been observed in detail. In further work, two such examples are presented and analyzed: a flaring, deeply embedded protostar in Orion and a flaring binary T~Tauri system whose activity is due to inter-binary coronal interaction. The earliest stages: Magnetic fields in molecular clouds - While mapping molecular clouds in polarized dust continuum emission has become a standard technique, the potentially more powerful technique using the "Goldreich-Kylafis" effect has been only rarely used until now. This effect predicts weakly linearly polarized molecular line emission under certain circumstances. By choosing different transitions, it is possible to probe the magnetic field direction in different regions in a molecular cloud core, and additionally one gets information along the line of sight for optically thin emission lines. The XPOL correlation polarimeter at the IRAM 30m telescope was used in a search for such linearly polarized emission in several bright molecular transition lines towards prominent star-forming regions. The combined effects of instrumental polarization and extended emission were simulated for a thorough interpretation of the results. In one case, the observed polarization exceeds the simulated instrumental value.

Forbrich, Jan

2007-02-01

134

Identification of inorganic dust particles in bronchoalveolar lavage macrophages by energy dispersive x-ray microanalysis  

SciTech Connect

This study shows that energy dispersive x-ray microprobe analysis to identify and quantify intracellular particles in macrophages obtained by the minimally invasive method of bronchoalveolar lavage (BAL) can detect inorganic dust exposures of many different kinds. Bronchoalveolar lavage macrophages from 22 patients have been examined. Twelve patients had occupational exposure to asbestos, talc, silica, hard metal or printing ink, while 10 had no known history of dust exposure. X-ray microprobe analysis identified particles which related to the known exposures, superimposed on a background of other particles related to smoking (kaolinite and mica) or to the general environment (silicon, titanium, and iron). The particle identification provided useful objective confirmation of the known exposures, except for silica, which could not be distinguished from the general background levels. X-ray microanalysis using BAL macrophages can be helpful for clarification of mixed dust exposures, to identify particles when light microscopy indicates retained dust in patients with no known history of exposure, and to monitor retained particles after removal from exposure.

Johnson, N.F.; Haslam, P.L.; Dewar, A.; Newman-Taylor, A.J.; Turner-Warwick, M.

1986-05-01

135

X-ray microscopy  

Microsoft Academic Search

Recent years have seen significant advances in both low and high energy X-ray microscopy. The image in X-ray microscopy is usually formed by differences in absorption of X-ray photons. Soft X-ray microscopy (energies below a few thousand eV) uses wavelengths under 10 nm. Since light wavelengths are approximately 500 nm, resolution is much better with X-rays. One can obtain nanoscale

Stanislave I. Rokhlin; Jin-Yeon Kim; B. Zoofan

2003-01-01

136

Quantitative analysis of annealed scanning probe tips using energy dispersive x-ray spectroscopy  

NASA Astrophysics Data System (ADS)

A quantitative method to measure the reduction in oxide species on the surface of electrochemically etched tungsten tips during direct current annealing is developed using energy dispersive x-ray spectroscopy. Oxide species are found to decrease with annealing current, with the trend repeatable over many tips and along the length of the tip apex. A linear resistivity approximation finds significant oxide sublimation occurs at 1714 K, but surface melting and tip broadening at 2215 K. This method can be applied to calibrate any similar annealing stage, and to identify the tradeoff regime between required morphological and chemical properties.

Cobley, R. J.; Brown, R. A.; Barnett, C. J.; Maffeis, T. G. G.; Penny, M. W.

2013-01-01

137

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

USGS Publications Warehouse

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

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

1984-01-01

138

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

SciTech Connect

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

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

2011-07-15

139

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

SciTech Connect

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

Zaluzec, N.J.

1988-08-01

140

MULTI-WAVELENGTH STUDY OF THE Be/X-RAY BINARY MXB 0656-072  

SciTech Connect

We present and analyze the optical photometric and spectroscopic data of the Be/X-ray binary MXB 0656-072 from 2006 to 2009. A 101.2 day orbital period is found, for the first time, from the present public X-ray data (Swift/BAT and RXTE/ASM). The anti-correlation between the H{alpha} emission and the UBV brightness of MXB 0656-072 during our 2007 observations indicates that a mass ejection event took place in the system. After the mass ejection, a low-density region might develop around the Oe star. With the outward motion of the circumstellar disk, the outer part of the disk interacted with the neutron star around its periastron passage and a series of X-ray outbursts were triggered between MJD 54350 and MJD 54850. The Proportional Counter Array-HEXTE spectra during the 2007-2008 X-ray outbursts could be well fitted by a cutoff power law with low-energy absorption, together with an iron line around 6.4 keV, and a broad cyclotron resonance feature around 30 keV. The same variability of the soft and hard X-ray colors in 2.3-21 keV indicated that there were no overall changes in the spectral shape during the X-ray outbursts, which might only be connected with the changes of the mass accretion rate onto the neutron star.

Yan Jingzhi; Li Hui; Liu Qingzhong [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zurita Heras, Juan Antonio; Chaty, Sylvain, E-mail: jzyan@pmo.ac.cn, E-mail: hli@pmo.ac.cn, E-mail: qzliu@pmo.ac.cn, E-mail: juan-antonio.zurita-heras@cea.fr, E-mail: sylvain.chaty@cea.fr [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d'Astrophysique, FR-91191 Gif-sur-Yvette (France)

2012-07-01

141

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

142

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

143

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

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

144

X-ray Emission Collected in a Novel Energy Dispersive Approach  

NASA Astrophysics Data System (ADS)

Novel methods & materials have been used to produce dynamically bent Bragg diffraction analyzer crystals in a modified von Hamos geometry.They are used to collect a wide energy range X-ray emission spectrum over a large solid angle with electron volt resolution. Crystals fabricated from silicon-on-insulator wafers by photolithography and deep reactive ion etching can bend to 10 cm radius without increased lattice strain. The design permits adjustment of energy dispersion for individual analyzers in an array. A multilayer mono, mono-capillary focusing, and multi-crystal spectrometer together collect signals at a bend magnet beamline comparable to those from an undulator. Preliminary measurements validate this new energy dispersive spectrometer.

Finkelstein, K. D.; Agyeman-Budu, D.; Lyndaker, A.; Pollock, C.; Krawczyk, T.

2014-03-01

145

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

SciTech Connect

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

Reagan, Brendon [Colorado State University, Fort Collins] [Colorado State University, Fort Collins; Berrill, Mark A [ORNL] [ORNL; Wernsing, Keith [Colorado State University, Fort Collins] [Colorado State University, Fort Collins; Baumgarten, Cory [Colorado State University, Fort Collins] [Colorado State University, Fort Collins; Woolston, Mark [Colorado State University, Fort Collins] [Colorado State University, Fort Collins; Rocca, Jorge [Colorado State University, Fort Collins] [Colorado State University, Fort Collins

2014-01-01

146

[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

147

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

148

THE CHANDRA MULTI-WAVELENGTH PROJECT: OPTICAL SPECTROSCOPY AND THE BROADBAND SPECTRAL ENERGY DISTRIBUTIONS OF X-RAY-SELECTED AGNs  

SciTech Connect

From optical spectroscopy of X-ray sources observed as part of the Chandra Multi-wavelength Project (ChaMP), we present redshifts and classifications for a total of 1569 Chandra sources from our targeted spectroscopic follow-up using the FLWO/1.5 m, SAAO/1.9 m, WIYN 3.5 m, CTIO/4 m, KPNO/4 m, Magellan/6.5 m, MMT/6.5 m, and Gemini/8 m telescopes, and from archival Sloan Digital Sky Survey (SDSS) spectroscopy. We classify the optical counterparts as 50% broad-line active galactic nuclei (AGNs), 16% emission line galaxies, 14% absorption line galaxies, and 20% stars. We detect QSOs out to z {approx} 5.5 and galaxies out to z {approx} 3. We have compiled extensive photometry, including X-ray (ChaMP), ultraviolet (GALEX), optical (SDSS and ChaMP-NOAO/MOSAIC follow-up), near-infrared (UKIDSS, Two Micron All Sky Survey, and ChaMP-CTIO/ISPI follow-up), mid-infrared (WISE), and radio (FIRST and NVSS) bands. Together with our spectroscopic information, this enables us to derive detailed spectral energy distributions (SEDs) for our extragalactic sources. We fit a variety of template SEDs to determine bolometric luminosities, and to constrain AGNs and starburst components where both are present. While {approx}58% of X-ray Seyferts (10{sup 42} erg s{sup -1} < L{sub 2-10keV} <10{sup 44} erg s{sup -1}) require a starburst event (>5% starburst contribution to bolometric luminosity) to fit observed photometry only 26% of the X-ray QSO (L{sub 2-10keV} >10{sup 44} erg s{sup -1}) population appear to have some kind of star formation contribution. This is significantly lower than for the Seyferts, especially if we take into account torus contamination at z > 1 where the majority of our X-ray QSOs lie. In addition, we observe a rapid drop of the percentage of starburst contribution as X-ray luminosity increases. This is consistent with the quenching of star formation by powerful QSOs, as predicted by the merger model, or with a time lag between the peak of star formation and QSO activity. We have tested the hypothesis that there should be a strong connection between X-ray obscuration and star formation but we do not find any association between X-ray column density and star formation rate both in the general population or the star-forming X-ray Seyferts. Our large compilation also allows us to report here the identification of 81 X-ray Bright Optically inactive Galaxies, 78 z > 3 X-ray sources, and eight Type-2 QSO candidates. Also, we have identified the highest redshift (z = 5.4135) X-ray-selected QSO with optical spectroscopy.

Trichas, Markos; Green, Paul J.; Aldcroft, Tom; Kim, Dong-Woo; Mossman, Amy [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Silverman, John D. [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, Kashiwanoha 5-1-5, Kashiwa-shi, Chiba 277-8568 (Japan); Barkhouse, Wayne [Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND 58202 (United States); Cameron, Robert A. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Constantin, Anca [Department of Physics and Astronomy, James Madison University, PHCH, Harrisonburg, VA 22807 (United States); Ellison, Sara L. [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P 1A1 (Canada); Foltz, Craig [Division of Astronomical Sciences, National Science Foundation, 4201 Wilson Blvd., Arlington, VA 22230 (United States); Haggard, Daryl [Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Jannuzi, Buell T. [NOAO, Kitt Peak National Observatory, Tucson, AZ 85726 (United States); Marshall, Herman L. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States); Perez, Laura M. [Department of Astronomy, California Institute of Technology, 1200 East California Blvd, Pasadena, CA 91125 (United States); Romero-Colmenero, Encarni [South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa); Ruiz, Angel [Osservatorio Astronomico di Brera-INAF, Milan (Italy); Smith, Malcolm G., E-mail: mtrichas@cfa.harvard.edu [Cerro Tololo Interamerican Observatory, La Serena (Chile); and others

2012-06-01

149

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

150

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

NASA Astrophysics Data System (ADS)

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 explosives and common materials. In order to quantify spectral resolution influence, this procedure is repeated with two different detectors which have different spectral resolution. Using our database, some standard spectrum analysis procedures generally used for this application have been implemented. Regarding to the results, it is possible to conclude on the robustness and the limits of each analysis procedure. The aim of this work is to define a robust and efficient sequence of EDXRD spectra analysis to discriminate explosive substances. Since our explosive substances are crystalline, the first step consists in using characteristic of the spectrum to estimate a crystallinity criterion which allows to remove a large part of common materials. The second step is a more detailed analysis, it consists in using similarity criterion and major peaks location to differentiate explosive from crystalline common materials. The influence of the spectral resolution on the detection is also examined.

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

2010-11-01

151

Angle-Dispersive X-ray Diffraction Study of Energetic Materials  

NASA Astrophysics Data System (ADS)

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

Gump, Jared; Peiris, Suhithi

2004-03-01

152

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

USGS Publications Warehouse

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

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

2005-01-01

153

The optimization of an energy-dispersive X-ray diffraction system for potential clinical application.  

PubMed

In the past decade, energy-dispersive X-ray diffraction (EDXRD) has been used to identify the nature of tissues. However, these systems have limited clinical use because of problems such as the long measurement times. In this study, the relation between various setup parameters and some performance specifications such as sensitivity, spatial resolution and momentum transfer resolution were assessed using both geometrical calculations and modeling. Accuracy of the derived relations was also confirmed by means of experimental measurements. As an example, the optimum parameters were determined for obtaining diffraction patterns of breast tissue for an efficient acquisition time. Accordingly, the results of this study could introduce a useful tool for EDXRD optimization in clinical application. PMID:20674378

Chaparian, A; Oghabian, M A; Changizi, V; Farquharson, M J

2010-12-01

154

Quantitative mineral phase analysis of dry powders using energy-dispersive X-ray diffraction.  

PubMed

Energy-dispersive X-ray diffraction (EDXRD) spectrometry is being investigated as a means to perform direct on-line quantitative mineral phase analysis on industrial mineral process streams. A laboratory prototype EDXRD analyser has been developed and a preliminary study has been made to determine its suitability for measuring mineral samples. This was carried out by collecting the diffraction spectra of 20 samples each containing six powdered minerals in dry form and using a linear regression analysis model to determine the mass of each mineral component contained in the samples. Using this method it was found that mineral components could be determined to an accuracy of better than 1 wt%. PMID:18502649

O'Dwyer, J N; Tickner, J R

2008-10-01

155

Minimum detectable limits of measuring bone mineral density using an energy dispersive X-ray diffraction system  

NASA Astrophysics Data System (ADS)

In the clinical environment, the most common method of assessing bone mineral density (BMD) loss is dual energy X-ray absorptiometry (DEXA), which relies on the transmission of X-ray photons through the volume of interest. Energy dispersive X-ray diffraction (EDXRD), which utilises coherent X-ray scattering, potentially is a more accurate method. As part of the development of a precision EDXRD system, an experiment was performed using a range of bone and fat mix phantoms, which were also used for DEXA evaluation. The results are presented here and suggest initial minimum detectable limits of the order of 5% BMD loss for the EDXRD experiment and 10-15% for the DEXA assessment.

Allday, A. W.; Farquharson, M. J.

2001-06-01

156

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

157

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

SciTech Connect

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 deg. C, 0-6 GPa) and the occurrence of a Bi crystalline structure isomorphic to the {beta}-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. [CNISM and Dipartimento di Fisica, Universita degli Studi di Camerino, via Madonna delle Carceri 9, 62032 Camerino (Monaco) (Italy); European Synchrotron Radiation Facility, Boite Postale 220, F-38043 Grenoble (France)

2006-08-01

158

Debye Temperature and Static Displacements in LuH/sub X/ Single Crystals from Energy Dispersive X-Ray Diffraction.  

National Technical Information Service (NTIS)

Integrated Bragg intensities of LuH/sub x/ along the hexagonal c-direction have been measured by energy-dispersive x-ray diffraction as a function of temperature and hydrogen concentration x less than or equal to 0.133 H/Lu. From the temperature-dependent...

T. H. Metzger P. Vajda J. N. Daou

1985-01-01

159

High-energy x-ray anomalous dispersion correction for silicon  

NASA Astrophysics Data System (ADS)

Energy-dependent structure factors measured by Saka and Kato [Acta Crystallogr., Sect. A 43, 252 (1987); 43, 255 (1987)] for silicon are analyzed, and values of the real part of the anomalous dispersion correction term f'(?) extracted for 12 wavelengths in the range 0.3-0.8 Å with an estimated accuracy of a few millielectrons. This is the first experimental set of such data for wavelengths less than 0.56 Å. The agreement with previous high-accuracy data for 0.56 and 0.71 Å is very good. Comparison with nonrelativistic and relativistic theoretical calculations shows excellent agreement down to 0.4 Å with very recent relativistic calculations including multipole and retardation terms. For shorter wavelengths a small deviation between theory and experiment is observed. Possible causes for this are discussed.

Deutsch, Moshe; Hart, Michael

1988-02-01

160

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

161

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...

162

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

163

Microcalorimeter-type energy dispersive X-ray spectrometer for a transmission electron microscope.  

PubMed

A new energy dispersive X-ray spectrometer (EDS) with a microcalorimeter detector equipped with a transmission electron microscope (TEM) has been developed for high- accuracy compositional analysis in the nanoscale. A superconducting transition-edge-sensor-type microcalorimeter is applied as the detector. A cryogen-free cooling system, which consists of a mechanical and a dilution refrigerator, is selected to achieve long-term temperature stability. In order to mount these detector and refrigerators on a TEM, the cooling system is specially designed such that these two refrigerators are separated. Also, the detector position and arrangement are carefully designed to avoid adverse affects between the superconductor detector and the TEM lens system. Using the developed EDS system, at present, an energy resolution of 21.92 eV full-width-at-half maximum has been achieved at the Cr K alpha line. This value is about seven times better than that of the current typical commercial Si(Li) detector, which is usually around 140 eV. The developed microcalorimeter EDS system can measure a wide energy range, 1-20 keV, at one time with this high energy resolution that can resolve peaks from most of the elements. Although several further developments will be needed to enable practical use, highly accurate compositional analysis with high energy resolution will be realized by this microcalorimeter EDS system. PMID:19717388

Hara, Toru; Tanaka, Keiichi; Maehata, Keisuke; Mitsuda, Kazuhisa; Yamasaki, Noriko Y; Ohsaki, Mitsuaki; Watanabe, Katsuaki; Yu, Xiuzhen; Ito, Takuji; Yamanaka, Yoshihiro

2010-01-01

164

Low-Voltage Energy-Dispersive X-ray Microanalysis of Bulk Biological Materials  

NASA Astrophysics Data System (ADS)

: Low-voltage energy-dispersive X-ray microanalysis has a number of distinct advantages for measuring the concentration of light elements (Z = 11 20) in a largely organic matrix. Between 10 and 4 kV, there is a 50-fold decrease in the size of the incident beam-specimen interaction volume which enables discrete subcellular compartments to be analyzed. Experiments with mineral and organic samples of known chemical composition show that two of the most widely used analytical algorithms are capable of providing quantitative data at accelerating voltages as low as 5 kV. This technique is used at 5 kV to analyze frozen hydrated fracture faces of leaves of the tea plant which are known to contain aluminium. Higher levels of aluminium are found in the cell walls and are associated with increased levels of silicon and magnesium. The advantages and disadvantages of the experimental approach are discussed in relation to analysis carried out at higher voltages.

Echlin, Patrick

1998-11-01

165

Smectic ordering in liquid-crystal aerosil dispersions.?I.?X-ray scattering  

NASA Astrophysics Data System (ADS)

Comprehensive x-ray scattering studies have characterized the smectic ordering of octylcyanobiphenyl (8CB) confined in the hydrogen-bonded silica gels formed by aerosil dispersions. For all densities of aerosil and all measurement temperatures, the correlations remain short range, demonstrating that the disorder imposed by the gels destroys the nematic (N) to smectic-A (SmA) transition. The smectic correlation function contains two distinct contributions. The first has a form identical to that describing the critical thermal fluctuations in pure 8CB near the N-SmA transition, and this term displays a temperature dependence at high temperatures similar to that of the pure liquid crystal. The second term, which is negligible at high temperatures but dominates at low temperatures, has a shape given by the thermal term squared and describes the static fluctuations due to random fields induced by confinement in the gel. The correlation lengths appearing in the thermal and disorder terms are the same and show a strong variation with gel density at low temperatures. The temperature dependence of the amplitude of the static fluctuations further suggests that nematic susceptibility becomes suppressed with increasing quenched disorder. The results overall are well described by a mapping of the liquid-crystal aerosil system onto a three-dimensional XY model in a random field with disorder strength varying linearly with the aerosil density.

Leheny, R. L.; Park, S.; Birgeneau, R. J.; Gallani, J.-L.; Garland, C. W.; Iannacchione, G. S.

2003-01-01

166

Geopolymerisation Kinetics. 1. In situ Energy-Dispersive X-ray Diffractometry  

SciTech Connect

In situ energy-dispersive X-ray diffractometry, using a polychromatic synchrotron beam and a 'laboratory-sized' sample, is used to provide a direct measurement of the kinetics of geopolymerisation. The effects of sample SiO{sub 2}/Al{sub 2}O{sub 3} ratio, Na/(Na+K) ratio and reaction temperature are investigated. The results obtained support recent propositions that the initial gel phase formed during geopolymerisation is later transformed to a second, probably more-ordered gel phase, and provide detailed information regarding the rate of formation of the first gel phase during the first 3 h of reaction. Increasing the SiO{sub 2}/Al{sub 2}O{sub 3} ratio generally decreases the initial rate of reaction, with the highest SiO{sub 2}/Al{sub 2}O{sub 3} ratio samples showing what appears to be a pause in the reaction corresponding roughly to the solidification of the geopolymeric binder. Mixed (Na,K)-aluminosilicate geopolymers with moderate SiO{sub 2}/Al{sub 2}O{sub 3} ratios behave similarly to pure Na- or K-aluminosilicate compositions of higher SiO{sub 2}/Al{sub 2}O{sub 3} ratio. Fitting a simplified first-order rate expression to the overall reaction process at different temperatures allows the calculation of an effective overall activation energy, which may be useful in comparing geopolymerisation of slurries with different compositions.

Provis,J.; van Deventer, J.

2007-01-01

167

An energy dispersive x-ray scattering and molecular dynamics study of liquid dimethyl carbonate  

NASA Astrophysics Data System (ADS)

In this work, we report on the first x-ray diffraction study on liquid dimethyl carbonate. Diffraction spectra were collected with an energy-dispersive instrument, whose wide Q-range allows the structure determination of weakly ordered systems (such as liquids). The structural correlation in this liquid ranges up to about 20 A?. The observed patterns are interpreted with a structural model derived from classical molecular dynamics simulations. The simulations were run using OPLS force field, only slightly modified to restrain bond distances to the experimental values. The model structure function and radial distribution functions, averaged among the productive trajectory frames, are in very good agreement with the corresponding experimental ones. Molecular dynamics results show that the deviations from C2v cis-cis structure, predicted by ab initio calculations and observed by electron diffraction in the gas phase, are small. By analyzing the intra- and intermolecular pair distribution functions, it was possible to assign the peaks of the experimental radial distribution function to specific structural correlations, and to compute the different average intermolecular coordination numbers. The intermolecular methyl-carbonyl oxygen distance is thoroughly discussed to assess the presence of weak C-H....O hydrogen bonds.

Gontrani, Lorenzo; Russina, Olga; Marincola, Flaminia Cesare; Caminiti, Ruggero

2009-12-01

168

HEAO-B X-ray experiments. Non-dispersive spectroscopy  

NASA Technical Reports Server (NTRS)

The scientific objectives of HEAO-B are presented. They include four X-ray and gamma ray experiments in addition to two charged cosmic ray experiments. The first X-ray experiment is one using standard proportional counters, mechanically collimated, and covers the region from 0.2 to 60 keV. It is being designed for the purpose of detecting small changes in the surface brightness of the X-ray sky over a very broad spectral range. The second X-ray experiment involves Bragg crystal spectrometers for the range 0.5 to 10 keV. In the low energy gamma ray experiment, which also extends into the X-ray region, a cooled germanium (lithium drifted) gamma-ray spectrometer was used.

Boldt, E. A.

1973-01-01

169

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

SciTech Connect

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

Chapline, G.F.

1983-01-12

170

On the use of polycapillary structures to improve laboratory Energy-Dispersive X-ray Diffractometry and Reflectometry  

NASA Astrophysics Data System (ADS)

One of the major limits of the laboratory X-ray sources is represented by their low photon flux which induces many researchers to move to synchrotron beamlines. From this point of view, polycapillaries lenses represent an extraordinary tool to improve the performances of laboratory machine and, indeed, several models of polycapillary optics-based instruments, such as diffractometers, spectrometers etc., are currently available on the market. In this work, the application of polycapillary optics to a particular kind of non-commercial X-ray instruments, namely the Energy-Dispersive X-ray Diffractometers and Reflectometers, is proposed. The advantages and limits of the use of polycapillaries are discussed and the results of preliminary experiments are shown.

Rossi Albertini, V.; Paci, B.; Generosi, A.; Dabagov, S. B.; Mikhin, O.; Kumakhov, M. A.

2007-11-01

171

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

Microsoft Academic Search

The quantum efficiency is measured 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, detectors with fluffy CsI semitransparent photocathodes are more efficient than those with opaque photocathodes of solid CsI, but the opposite is true at longer wavelengths. Fluffy CsI semitransparent

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

1986-01-01

172

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

Microsoft Academic Search

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

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

1986-01-01

173

Prototype of the high sensitive X-ray microcalorimeter for X-ray imaging  

Microsoft Academic Search

An X-ray microcalorimeter is a high performance X-ray spectrometer that can achieve both high energy resolution of conventional wavelength dispersive spectrometers (WDS) and high quantum efficiency of energy dispersive spectrometers (EDS). The energy resolution can be theoretically improved to about 1eV, which value is 120 times better than that of conventional Si(Li) spectrometers and nearly 100% of quantum efficiency can

H. Kudo; T. Nakamura; T. Arakawa; S. Ohtsuka; T. Izumi; S. Shoji; H. Sato; H. Kobayashi; K. Mori; T. Homma; T. Osaka; K. Mitsuda; N. Y. Yamasaki; R. Fujimoto; N. Iyomoto; T. Oshima; K. Futamoto; Y. Takei; T. Ichitsubo; T. Fujimori; Y. Ishisaki; U. Morita; T. Koga; K. Sato; T. Ohashi; Y. Kuroda; M. Onishi; K. Otake; F. Beppu

2004-01-01

174

Sulfur distribution in bacteriorhodopsin from multiple wavelength anomalous diffraction near the sulfur K-edge with synchrotron x-ray radiation.  

PubMed Central

Bacteriorhodopsin contains nine sulfur atoms from the nine methionine residues. The distribution of these sulfur atoms in the projected density map was determined from x-ray diffraction experiments using multiple wavelength anomalous diffraction (MAD) at the sulfur K-edge (5.02 A) with synchrotron radiation. The experiments were performed with uniaxial samples of oriented purple membranes at room temperature and 86% relative humidity. For such samples only the real part f' (lambda) of the resonant scattering amplitude of sulfur contributes to the observed scattering intensity. The sulfur density was determined from the difference in diffraction intensities detected at two wavelengths near the sulfur K-edge that were approximately 0.004 A apart. The measured change in f' between these two wavelengths corresponds to 6 electron units. This shows that large anomalous dispersion effects occur near the sulfur K-edge. The in-plane positions of the sulfur atoms of Met32, Met56, and Met209 were determined unambiguously. The difference density from Met20, Met60, Met118, and Met145 is concentrated in the interior of the seven alpha-helical bundle, overlaps strongly in the projected density map, and cannot be resolved at the resolution of these experiments (8.2 A). This method of localizing individual sulfur atoms can be applied to other two-dimensional protein crystals and is promising in conjunction with the site-directed introduction of sulfur atoms by the use of cysteine mutants.

Behrens, W; Otto, H; Stuhrmann, H B; Heyn, M P

1998-01-01

175

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

176

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

177

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

NASA Astrophysics Data System (ADS)

A room-temperature RF undulator, fed by Ka-band radiation and intended to produce ~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.

2012-12-01

178

Dispersion of V2O5 supported on a TiO2 by x-ray photoelectron spectroscopy surface  

NASA Astrophysics Data System (ADS)

The dispersion of V2O5 in V2O5/TiO2 catalysis has been studied by x-ray photoelectron spectroscopy, transmission electron microscopy and a thermal gravimetric analysis for samples with various V2O5 content. The coverage, thickness and dispersion of vanadium oxide were calculated by a quantitative x-ray photoelectron spectroscopy (XPS) analysis. The experimental results show that V2O5 is well dispersed on a TiO2 surface at low VEOs content. The coverage increases rapidly with the V2O5 content up to 10 wt%. Beyond that, the coverage increases very slowly, and considerable parts of the TiO2 surface remain bare even at a V2O5 content as high as 40 wt%. The vanadium oxide is probably present on the TiO2 surface as isolated patches or islands. This investigation shows that x-ray photoelectron spectroscopy is also a powerful tool for obtaining information about the dispersion of supported species in catalytic research.

Liu, Zhenxiang; Lin, Zhangda; Fan, Hanjie; Li, Fangha; Bao, Qixun; Zhang, Shugui

1988-08-01

179

In Situ High Pressure Angle Dispersive X-ray Diffraction Experiments:With Sagittally-Bent Double Laue Monochomator  

NASA Astrophysics Data System (ADS)

A Sagittally-bent double Laue monochomator is used at the wiggler beam line X17C of NSLS, BNL. It can provide high-energy X-ray tunable from 20 keV to 40 keV. The monochomator consists of two Si crystals of 0.76 mm thick, with surface corresponding to the (001) planes. The 111 reflections of both crystals are used to diffract the x-ray. The two crystals are bent Sagittelly to 1 m radius and used in the Laue mode [1, 2]. The bent Laue crystals provide high energy-resolution beam with a flux one order of magnitude greater than that of a flat-crystal monochromator. For high-pressure diamond-anvil cell experiments using angular dispersive x-ray diffraction, K-B mirrors are used to focus the incident beam from 0.180mm x 0.180mm to 0.025mm x 0.025mm. Two samples were studied with different x-ray energies. The Ag2O2 sample was studied at pressures up to 20 GPa using energy of 38.9246 keV (0.031851 nm) x-ray. The problem of strong Ag fluorescence causing Ge-detector to saturate in energy dispersive x-ray diffraction was not an issue in the present angular dispersive experiments. With energy of 30.4912keV (0.040663 nm) x-ray, NaMgF3 was studied to 30 GPa. Exposure time was 1 to 6 minutes for different pressures. No phase transition was found in the pressure range. The P-V data fitting to a third order Birch- Murnahgan equation yields a bulk modulus Ko=68.9 1.7 GPa and Ko­_=6.3. [1] Z. Zhong, et. al., Acta. Cryst. A 59 (2003) 1-6 [2] Z. Zhong, et. al. J. Appl. Cryst., 34 (2001) 646-653

Hu, J.; Zhong, Z.; Liu, H.; Guo, Q.; Mao, H.; Hemley, R. J.

2003-12-01

180

Determination of High Zn and Pb Concentrations in Polluted Soils Using Energy-Dispersive X-ray Fluorescence Spectrometry  

Microsoft Academic Search

A method of determination of high Zn and Pb concentrations by means of EDXRF (energy-dispersive X-ray fluorescence spectrometry) is presented. Zn and Pb concentration in soil samples from contami- nated areas ranged within a limit of Zn: 800-2000ppm and Pb: 200-600ppm. Soil analysis was conducted directly after the samples had been dried and powdered, as well as in situ in

R. Sitko; B. Zawisza; J. Jurczyk; F. Buhl; U. Zielonka

181

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

Microsoft Academic Search

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

John Baker

1991-01-01

182

Is scanning electron microscopy\\/energy dispersive x-ray spectroscopy (SEM\\/EDS) quantitative? Effect of specimen shape  

Microsoft Academic Search

The extraordinary throughput of the silicon drift detector energy dispersive x-ray spectrometer (SDD-EDS) enables collection of EDS spectra with much higher integrated counts within practical time periods, e.g., 100 s or less, compared to past experience with the Si(Li)-EDS. Such high count SDD spectra, containing one million to ten million counts, yield characteristic peak intensities with relative standard deviation below

Dale E. Newbury; Nicholas W. M. Ritchie

2011-01-01

183

Determination of calcium and iodine in gall bladder stone using energy dispersive X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

Energy dispersive X-ray fluorescence techniques were used to analyze gall bladder stones. Enrichment of Ca and I was observed in the gall bladder stone taken from a patient. The concentration of Ca has been determined with an annular 55Fe radioactive source and the concentration of I with an annular 241Am radioactive source using the standard addition method in 2? geometry. A Si(Li)-detector was used to measure Ca and I concentrations in the gall bladder stones.

Ekinci, Neslihan; ?ahin, Yusuf

2002-01-01

184

Benthic Algae as Monitors of Heavy Metals in Various Polluted Rivers by Energy Dispersive X-Ray Spectrometer  

Microsoft Academic Search

Benthic microalgae assemblages were used as monitors of copper (Cu), zinc (Zn), and chromium (Cr) in various polluted rivers of San-Yeh-Kong, in southern Taiwan, and analyzed using Scanning Electron Microscope and Energy Dispersive X-Ray Spectrometer (SEM-EDS). Under SEM-EDS, the benthic algae from seriously polluted rivers (dominant by the cyanobacteria Oscillatoria chalybea, green algae Euglena acus and diatom Nitzschia palea under

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

2003-01-01

185

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

Microsoft Academic Search

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

Leland

1989-01-01

186

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

187

X-ray microanalysis as applied to fungal tissues.  

PubMed Central

Analytical electron microscopy combines the techniques of high-resolution electron microscopy and high-sensitivity X-ray microanalysis of samples. Spectrometry of the elements (characteristic X-rays produced by a scanning electron microprobe) was employed to detect some elements of Mendeleev's classification in pathogenic fungi for humans. X-ray microanalysis applied in wavelength dispersive spectrometry was used to study Coccidioïdes immitis, Paracoccidioïdes brasiliensis and Trichosporum cutaneum. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

Thibaut, M.; Ansel, M.; de Azevedo Carneiro, J.

1977-01-01

188

Novel parallel vacuum ultra-violet/X-ray fluorescence spectrometer  

NASA Astrophysics Data System (ADS)

Novel instrumentation developments in X-ray spectroscopy for parallel spectral measurements with soft X-rays are described. The significant performance improvements are achieved utilising Fresnel diffraction from structures built onto the surface of a total external reflection mirror. An array of reflection zone plates was tested as a wavelength-dispersive fluorescence spectrometer for soft X-rays in the energy range of 100-550 eV.

Erko, A.; Firsov, A.; Senf, F.

2012-01-01

189

Study of heavy metals and other elements in macrophyte algae using energy-dispersive X-ray fluorescence  

SciTech Connect

Fucus vesiculosus L. seaweeds from three estuarine stations were analyzed by X-ray fluorescence, providing results for the concentration of total K, Ca, Ti, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Sr, and Pb. Four different structures of the algae (base, stipe, reproductive organs, and growing tips) were analyzed to study the differential accumulation of heavy metals by different parts of Fucus. Some elements (e.g., Cu and Fe) are preferentially accumulated in the base of the algae, whereas others (e.g., As) exhibit higher concentrations in the reproductive organs and growing tips. The pattern of accumulation in different structures is similar for Cu, Zn, and Pb, but for other metals there is considerable variability in accumulation between parts of the plant. This is important in determining which structures of the plant should be used for biomonitoring. For samples collected at stations subject to differing metal loads, the relative elemental composition is approximately constant, notwithstanding significant variation in absolute values. The proportion of metals in Fucus is similar to that found in other estuaries, where metal concentrations are significantly lower. Energy-dispersive X-ray fluorescence has been shown to be a suitable technique for multielement analysis in this type of sample. No chemical pretreatment is required, minimizing sample contamination. The small amount of sample required, and the wide range of elements that can be detected simultaneously make energy-dispersive X-ray fluorescence a valuable tool for pollution studies.

Carvalho, M.L.; Amorim, P.; Marques, M.I.M.; Ramos, M.T. [Univ. de Lisboa (Portugal); Ferreira, J.G. [Faculdade de Ciencias e Tecnologia, Monte de Caparica (Portugal). Dept. Ciencias e Engenharia do Ambiente

1997-04-01

190

Chemical analysis of coal by energy dispersive x-ray fluorescence utilizing artificial standards  

Microsoft Academic Search

Accurate determinations of the elemental composition of coal by classical methods can be quite difficult and are normally very time consuming. X-ray fluorescence utilizing the powder method, however, has the ability of providing accurate and rapid analyses. Unfortunately, well characterized standards, although available, are not plentiful. In addition, the durability of stability of ground and pelletized coal samples is poor

Wheeler

1982-01-01

191

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

192

Angle Dispersive X-ray Diffraction Beamline on Indus-2 Synchrotron Radiation Source: Commissioning and First Results  

NASA Astrophysics Data System (ADS)

Angle dispersive x-ray diffraction (ADXRD) is a basic non destructive tool for the determination of crystal structure. Energy tunability and high flux are added advantages in using synchrotron radiation (SR) source for ADXRD technique. We have installed an ADXRD beamline (BL-12) on Indus-2, the Indian synchrotron source. Indus-2 is a 2.5GeV, 300mA SR source. The beamline consists of a Si (311) crystal pair based double crystal monochromator with bendable focusing optics. The experimental station consists of a six circle diffractometer with scintillation detector and an image plate area detector. The beamline has been used for wide range of experiments like powder and single crystal diffraction; grazing incidence diffraction, x-ray absorption near edge structure, Anomalous XRD, high pressure XRD etc. The beamline is being utilized by users from Indian universities and research institutions.

Sinha, A. K.; Sagdeo, Archna; Gupta, Pooja; Upadhyay, Anuj; Kumar, Ashok; Singh, M. N.; Gupta, R. K.; Kane, S. R.; Verma, A.; Deb, S. K.

2013-03-01

193

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

194

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

195

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

Microsoft Academic Search

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

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

2009-01-01

196

Type IIP Supernova SN 2004et: A Multi-Wavelength Study in X-Ray, Optical and Radio  

Microsoft Academic Search

We present X-ray, broad band optical and low frequency radio observations of\\u000athe bright type IIP supernova SN 2004et. The \\\\cxo observed the supernova at\\u000athree epochs, and the optical coverage spans a period of $\\\\sim$ 470 days since\\u000aexplosion. The X-ray emission softens with time, and we characterise the X-ray\\u000aluminosity evolution as $\\\\Lx \\\\propto t^{-0.4}$. We use the

Kuntal Misra; Dave Pooley; Poonam Chandra; D. Bhattacharya; Alak K. Ray; Ram Sagar; Walter H. G. Lewin

2007-01-01

197

An energy dispersive X-ray diffraction station at a VEPP-4 synchrotron beam line for structural studies at high pressure  

NASA Astrophysics Data System (ADS)

The energy dispersive X-ray diffraction (EDXRD) station at a VEPP-4 synchrotron beam line is presented. The first results obtained with a high pressure chamber at the VEPP-3 synchrotron beam line are shown.

Ancharov, A. I.; Tolochko, B. P.; Chidambaram, R.; Sikka, S. K.; Momin, S. N.; Vijayakumar, V.; Kulipanov, G. N.

1995-02-01

198

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

199

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

200

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

201

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

NASA Technical Reports Server (NTRS)

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 (0.001 cu mm) volumes deep within composite samples. The viability of the technique was tested using a model system with 800 micron Al203 fibers and a commercial purity titanium matrix. 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 microns or more from the fiber/matrix interface.

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

1993-01-01

202

High-Dispersion Spectroscopy of the X-Ray Transient RXTE J0421+560 (=CI Camelopardalis) during Outburst  

NASA Astrophysics Data System (ADS)

We obtained high-dispersion spectroscopy of CI Cam, the optical counterpart of XTE J0421+560, 2 weeks after the peak of its short outburst in 1998 April. The optical counterpart is a supergiant B[e] star that is emitting a two-component wind, a cool, low-velocity wind and a hot, high-velocity wind. The cool wind, which is the source of narrow emission lines of neutral and ionized metals, has a velocity of 32 km s-1 and a temperature near 8000 K. It is dense, roughly spherical, fills the space around the sgB[e] star, and, based on the size of an infrared-emitting dust shell around the system, extends to a radius between 13 and 50 AU. It carries away mass at a high rate, M>10-6Msolaryr-1. The hot wind has a velocity in excess of 2500 km s-1 and a temperature of 1.7+/-0.3×104 K. From an ultraviolet spectrogram of CI Cam obtained in 2000 March with Hubble Space Telescope, we derive a differential extinction E(B-V)=0.85+/-0.05. We show that the distance to CI Cam is greater than 5 kpc. Based on this revised distance, the X-ray luminosity at the peak of the outburst was L(2-25 keV)>3.0×1038 ergs s-1, making CI Cam one of the most luminous X-ray transients. The ratio of quiescent luminosity to peak luminosity in the 2-25 keV band is Lq/Lp<1.7×10-6. The compact star in CI Cam is immersed in the dense circumstellar wind from the sgB[e] star and burrows through the wind, producing little X-ray emission except for rare transient outbursts. This picture, a compact star traveling in a wide orbit through the dense circumstellar envelope of a sgB[e] star, occasionally producing transient X-ray outbursts, makes CI Cam unique among the known X-ray binaries. There is strong circumstantial evidence that the compact object is a black hole, not a neutron star. We speculate that the X-ray outburst was short because the accretion disk around the compact star is fed from a stellar wind and is smaller than disks fed by Roche lobe overflow. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Robinson, Edward L.; Ivans, Inese I.; Welsh, William F.

2002-02-01

203

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

NASA Astrophysics Data System (ADS)

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

Imashuku, Susumu; Sakatoku, Shota; Kawai, Jun

2013-08-01

204

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

205

Calibration of an argon in germanium standard using Rutherford backscattering spectrometry for energy dispersive x-ray spectroscopy  

SciTech Connect

An argon standard for energy dispersive x-ray spectroscopy (EDS) has been made by bias sputtering hydrogenated amorphous germanium (/ital a/-Ge:H) films and determining the concentration of argon with Rutherford backscattering spectrometry. Varying concentrations of argon in hydrogenated amorphous germanium were achieved by changing the dc bias on the substrate holder and the gas pressure during rf magnetron sputtering onto a silicon substrate. It was found that standardless EDS analysis underestimates the argon concentration by about a factor of 2.

Skulina, K. M.; van der Leeden, G. A.; Vincent, D. H.

1989-07-01

206

In-situ study of the growth of CuO nanowires by energy dispersive X-ray diffraction  

SciTech Connect

Growth of CuO nanowires by annealing method has been studied in-situ by grazing incidence Energy Dispersive X-ray Diffraction (EDXRD) technique on Indus-2. It was observed that Cu slowly oxidized to Cu{sub 2}O and finally to CuO. The data was taken as a function of time at two annealing temperatures 500 Degree-Sign C where nanowires form and 300 Degree-Sign C where nanowires don't form. We found that the strain in the CuO layer may be a principal factor for the spontaneous growth of nanowires in annealing method.

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

2013-02-05

207

Benzyne-functionalized graphene and graphite characterized by Raman spectroscopy and energy dispersive X-ray analysis  

PubMed Central

The benzyne functionalization of chemical vapor deposition grown large area graphene and graphite was performed using a mixture of o-trimethylsilylphenyl triflate and cesium fluoride that react with the carbon surface. The reaction requires at least 2 days of treatment before the appearance of Raman and energy-dispersive X-ray spectral signatures that verify modification. Raman spectra of modified graphene and graphite show a rich structure of lines corresponding to C=C-C, C-H, and low frequency modes of surface-attached benzyne rings.

Magedov, Igor V.; Frolova, Lilia V.; Ovezmyradov, Mekan; Bethke, Donald; Shaner, Eric A.; Kalugin, Nikolai G.

2012-01-01

208

In-situ study of the growth of CuO nanowires by energy dispersive X-ray diffraction  

NASA Astrophysics Data System (ADS)

Growth of CuO nanowires by annealing method has been studied in-situ by grazing incidence Energy Dispersive X-ray Diffraction (EDXRD) technique on Indus-2. It was observed that Cu slowly oxidized to Cu2O and finally to CuO. The data was taken as a function of time at two annealing temperatures 500°C where nanowires form and 300°C where nanowires don't form. We found that the strain in the CuO layer may be a principal factor for the spontaneous growth of nanowires in annealing method.

Srivastava, Himanshu; Ganguli, Tapas; Deb, S. K.; Sant, Tushar; Poswal, Himanshu; Sharma, S. M.

2013-02-01

209

An evaluation of multilayer mirrors for the soft x ray and extreme ultraviolet wavelength range that were irradiated with neutrons  

SciTech Connect

The Plasma Spectroscopy Group at the Johns Hopkins University develops high photon throughput multilayer mirror (MLM) based soft x ray and extreme ultraviolet (XUV 10 {Angstrom}{lt}{lambda}{lt}304 {Angstrom}) spectroscopic diagnostics for magnetically confined fusion plasmas. The D-T reactions in large fusion reactor type devices such as the International Thermonuclear Experimental Reactor will produce neutrons at a rate as high as 5{times}10{sup 19} ns{sup -1}. The MLMs, which are used as dispersive and focusing optics, will not be shielded from these neutrons. In an effort to assess the potential radiation damage, four MLMs (No. 1: Mo/Si, d=87.8 {Angstrom}, Zerodur substrate with 50 cm concave spherical curvature; No. 2: W/B{sub 4}C, d=22.75 {Angstrom}, Si wafer substrate; No. 3: W/C, d=25.3 {Angstrom}, Si wafer substrate; and No. 4: Mo/Si, d=186.6 {Angstrom}, Si wafer substrate) were irradiated with fast neutrons at the Los Alamos Spallation Radiation Effects Facility (LASREF). The neutron beam at LASREF has an energy distribution that peaks at 1{endash}2 MeV with a tail that extends out to 100 MeV. The MLMs were irradiated to a fast neutron fluence of 1.1{times}10{sup 19} ncm{sup {minus}2} at 270{endash}300{degree}C. A comparison between the dispersive and reflective characteristics of the irradiated MLMs and the corresponding qualities of control samples will be given. {copyright} {ital 1997 American Institute of Physics.}

Regan, S.P.; May, M.J.; Soukhanovskii, V.; Finkenthal, M.; Moos, H.W. [The Plasma Spectroscopy Group, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)] [The Plasma Spectroscopy Group, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218 (United States); Farnum, E.H.; Clinard, F.W. Jr. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Tarrio, C.; Watts, R. [National Institute of Standards and Technology, Gaithersburg, Maryland (United States)] [National Institute of Standards and Technology, Gaithersburg, Maryland (United States)

1997-01-01

210

Calibration of thickness-dependent k-factors for germanium X-ray lines to improve energy-dispersive X-ray spectroscopy of SiGe layers in analytical transmission electron microscopy  

NASA Astrophysics Data System (ADS)

We show that the accuracy of energy-dispersive X-ray spectroscopy can be improved by analysing and comparing multiple lines from the same element. For each line, an effective k-factor can be defined that varies as a function of the intensity ratio of multiple lines (e.g. K/L) from the same element. This basically performs an internal self-consistency check in the quantification using differently absorbed X-ray lines, which is in principle equivalent to an absorption correction as a function of specimen thickness but has the practical advantage that the specimen thickness itself does not actually need to be measured.

Qiu, Y.; Nguyen, V. H.; Dobbie, A.; Myronov, M.; Walther, T.

2013-11-01

211

Crystals for astronomical X-ray spectroscopy  

NASA Technical Reports Server (NTRS)

Crystal spectrometric properties and the factors that affect their measurement are discussed. Theoretical and experimental results on KAP are summarized and theoretical results based on the dynamical theory of X-ray diffraction are given for the acid phthalates as well as for the commonly used planes of ADP, PET and EDDT. Anomalous dispersion is found to be important for understanding the details of crystal Bragg reflection properties at long X-ray wavelengths and some important effects are pointed out. The theory of anomalous dispersion is applied to explain the anomalous reflectivity exhibited by KAP at 23.3 A.

Burek, A.

1976-01-01

212

Chemical analysis of coal by energy dispersive x-ray fluorescence utilizing artificial standards  

SciTech Connect

Accurate determinations of the elemental composition of coal by classical methods can be quite difficult and are normally very time consuming. X-ray fluorescence utilizing the powder method, however, has the ability of providing accurate and rapid analyses. Unfortunately, well characterized standards, although available, are not plentiful. In addition, the durability of stability of ground and pelletized coal samples is poor resulting in deterioration with time. As a result, artificial coal standards were prepared from certified geological materials by fusing in lithium tetraborate in percentages approximating expected ash contents and compositions in coal. Since the lithium tetraborate comprises about the same percentage of the standard as does the carbon, hydrogen, and oxygen in coal, the ground and pelletized coal sample can be assayed against the fused calibration curves by compensating for the differences in the mass absorption coefficients of the two matrices. 5 figures, 4 tables.

Wheeler, B.D.

1982-01-01

213

The effect of nonhydrostaticity on measuring the pressure in metals by energy dispersive X-ray diffraction in the diamond anvil cell  

Microsoft Academic Search

Using the Chua-Ruoff scaling relation for the pressure dependence of the compressive flow stress, the effect of the presence of a finite yield strength on the measurement of pressure in a diamond anvil cell by energy dispersive X-ray diffraction is calculated. In experiments in which the pressure was found by X-ray diffraction to be 364 GPa (exceeding the pressure at

Arthur L. Ruoff; Huan Luo; Hui Xia; Yogesh K. Vohra

1991-01-01

214

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

215

Effect of helium environment and mylar foil on the sensitivity of different elements in energy dispersive X-ray fluorescence spectroscopy  

Microsoft Academic Search

Analysis by Energy Dispersive X-Ray Fluorescence (ED-XRF) technique of liquid samples and specimens in aqueous media requires that the sample chamber be flushed with helium gas. Moreover the sample should also be covered with mylar foil to hold the sample. The helium environment and the X-ray beam but also affect the sensitivity of different elements. An investigation was carried out

R. P. Khatri

1989-01-01

216

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

217

Development of W/C soft x-ray multilayer mirror by ion beam sputtering (IBS) system for below 50A? wavelength  

NASA Astrophysics Data System (ADS)

A home-made Ion Beam Sputtering (IBS) system has been developed in our laboratory. Using the IBS system single layer W and single layer C film has been deposited at 1000eV Ar ion energy and 10mA ion current. The W-film has been characterized by grazing Incidence X-ray reflectrometry (GIXR) technique and Atomic Force Microscope technique. The single layer C-film has been characterized by Spectroscopic Ellipsometric technique. At the same deposition condition 25-layer W/C multilayer film has been deposited which has been designed for using as mirror at 30° grazing incidence angle around 50A? wavelength. The multilayer sample has been characterized by measuring reflectivity of CuK? radiation and soft x-ray radiation around 50A? wavelength.

Biswas, A.; Bhattacharyya, D.

2012-06-01

218

X-ray spectromicroscopy investigations of fast ions and hot electrons in plasmas, heated by nanosecond laser radiation with different wavelengths  

Microsoft Academic Search

Summary form only given. By means of space resolved X-ray spectroscopy we have investigated the generation of fast (up to MeV) ions for various laser installations with different flux densities (10 12-1014 W\\/cm2) and laser wavelengths (?=308 nm, 800 nm, 1.06 ?m, 10.6 ?m). The implementation of our spectroscopically determined data into the generally accepted scaling relation diagrams with the

A. Ya. Faenov; I. Yu. Skobelev; A. I. Magunov; T. A. Pikuz; F. B. Rosmej; D. H. H. Hoffmann; W. Suss; M. Geissel; R. Bock; T. Letardi; F. Flora; S. Bollanti; P. Di Lazzaro; Yu. A. Satov; Yu. B. Smakovskii; A. E. Stepanov; V. K. Roerich; S. V. Khomenko; S. Nischuk; K. N. Makarov; A. Reale; A. Scafati; T. Auguste; P. d'Oliveira; S. Hulin; P. Monot; B. Yu. Sharkov

2000-01-01

219

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

220

In situ profiling of lithium/Ag?VP?O? primary batteries using energy dispersive X-ray diffraction.  

PubMed

In situ, in operando characterization of electrochemical cells can provide insight into the complex discharge chemistries of batteries which may not be available with destructive methods. In this study, in situ energy-dispersive X-ray spectroscopy (EDXRD) measurements are conducted for the first time on active lithium/silver vanadium diphosphate, Li/Ag2VP2O8, electrochemical cells at several depths of discharge allowing depth profiling analysis of the reduction process. This technique enables non-destructive, in operando imaging of the reduction process within a battery electrode over a millimeter scale interrogation area with micron scale resolution. The discharge of Ag2VP2O8 progresses via a reduction displacement reaction forming conductive silver metal as a discharge product, a high Z material which can be readily detected by diffraction-based methods. The high energy X-ray capabilities of NSLS beamline X17B1 allowed spatially resolved detection of the reduction products forming conductive pathways providing insight into the discharge mechanism of Ag2VP2O8. PMID:24705594

Kirshenbaum, Kevin C; Bock, David C; Zhong, Zhong; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

2014-05-21

221

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

USGS Publications Warehouse

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

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

2014-01-01

222

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

223

Development of on-line energy dispersive x-ray fluorescence to monitor actinide-contaminated waste streams  

SciTech Connect

A commercially available on-line energy dispersive x-ray fluorescence (EDXRF) system has been modified for glove-box operations and installed on the Advanced Testing Line for Actinide Separations (ATLAS) at Los Alamos. The goal is to quantitatively monitor actinides and metal impurities in an anion-exchange effluent to obtain near-real-time chemical information. Because of recent compliance issues, metals listed in the Resource Conservation and Recovery Act and other low-level radioactive components are also being analyzed. Initial experiments on how preconcentration techniques can be applied to on-line EDXRF measurements for improved detection limits have also been conducted. An overview of these developments is presented in this paper.

Day, R.S.; Vigil, A.R.

1994-05-01

224

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

SciTech Connect

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

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

1993-04-01

225

X-ray Photon Counting Using 100 MHz Ready-Made Silicon P--Intrinsic--N X-ray Diode and Its Application to Energy-Dispersive Computed Tomography  

NASA Astrophysics Data System (ADS)

X-ray photons are directly detected using a 100 MHz ready-made silicon P--intrinsic--N X-ray diode (Si-PIN-XD). The Si-PIN-XD is shielded using an aluminum case with a 25-?m-thick aluminum window and a BNC connector. The photocurrent from the Si-PIN-XD is amplified by charge sensitive and shaping amplifiers, and the event pulses are sent to a multichannel analyzer (MCA) to measure X-ray spectra. At a tube voltage of 90 kV, we observe K-series characteristic X-rays of tungsten. Photon-counting computed tomography (PC-CT) is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by linear scanning at a tube current of 2.0 mA. The exposure time for obtaining a tomogram is 10 min with scan steps of 0.5 mm and rotation steps of 1.0°. At a tube voltage of 90 kV, the maximum count rate is 150 kcps. We carry out PC-CT using gadolinium media and confirm the energy-dispersive effect with changes in the lower level voltage of the event pulse using a comparator.

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

2013-07-01

226

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

Microsoft Academic Search

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

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

2003-01-01

227

Quantitative energy-dispersive electron probe X-ray microanalysis for single-particle analysis and its application for characterizing atmospheric aerosol particles  

Microsoft Academic Search

.  An energy-dispersive electron probe X-ray microanalysis (ED-EPMA) technique using an energy-dispersive X-ray detector with\\u000a an ultra-thin window, designated as low-Z particle EPMA, has been developed. The low-Z particle EPMA allows the quantitative determination of concentrations of low-Z elements such as C, N and O, as well as higher-Z elements that can be analysed by conventional ED-EPMA. The quantitative determination of

Shila Maskey; Chul-Un Ro

2011-01-01

228

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

229

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

230

Monte Carlo simulation of energy-dispersive x-ray fluorescence and applications  

NASA Astrophysics Data System (ADS)

Four key components with regards to Monte Carlo Library Least Squares (MCLLS) have been developed by the author. These include: a comprehensive and accurate Monte Carlo simulation code - CEARXRF5 with Differential Operators (DO) and coincidence sampling, Detector Response Function (DRF), an integrated Monte Carlo - Library Least-Squares (MCLLS) Graphical User Interface (GUI) visualization System (MCLLSPro) and a new reproducible and flexible benchmark experiment setup. All these developments or upgrades enable the MCLLS approach to be a useful and powerful tool for a tremendous variety of elemental analysis applications. CEARXRF, a comprehensive and accurate Monte Carlo code for simulating the total and individual library spectral responses of all elements, has been recently upgraded to version 5 by the author. The new version has several key improvements: input file format fully compatible with MCNP5, a new efficient general geometry tracking code, versatile source definitions, various variance reduction techniques (e.g. weight window mesh and splitting, stratifying sampling, etc.), a new cross section data storage and accessing method which improves the simulation speed by a factor of four and new cross section data, upgraded differential operators (DO) calculation capability, and also an updated coincidence sampling scheme which including K-L and L-L coincidence X-Rays, while keeping all the capabilities of the previous version. The new Differential Operators method is powerful for measurement sensitivity study and system optimization. For our Monte Carlo EDXRF elemental analysis system, it becomes an important technique for quantifying the matrix effect in near real time when combined with the MCLLS approach. An integrated visualization GUI system has been developed by the author to perform elemental analysis using iterated Library Least-Squares method for various samples when an initial guess is provided. This software was built on the Borland C++ Builder platform and has a user-friendly interface to accomplish all qualitative and quantitative tasks easily. That is to say, the software enables users to run the forward Monte Carlo simulation (if necessary) or use previously calculated Monte Carlo library spectra to obtain the sample elemental composition estimation within a minute. The GUI software is easy to use with user-friendly features and has the capability to accomplish all related tasks in a visualization environment. It can be a powerful tool for EDXRF analysts. A reproducible experiment setup has been built and experiments have been performed to benchmark the system. Two types of Standard Reference Materials (SRM), stainless steel samples from National Institute of Standards and Technology (NIST) and aluminum alloy samples from Alcoa Inc., with certified elemental compositions, are tested with this reproducible prototype system using a 109Cd radioisotope source (20mCi) and a liquid nitrogen cooled Si(Li) detector. The results show excellent agreement between the calculated sample compositions and their reference values and the approach is very fast.

Li, Fusheng

231

New Developments in X-Ray Optics  

NASA Astrophysics Data System (ADS)

Introduction What is or are X-ray optics? The fundamental interaction utilised in X-ray optics The challenge of X-ray optics in astronomy X-Ray Dispersion Theory The classical electromagnetic theory The origin of dispersion - optical constans for X rays The Kramers-Kronig relations- measuring and calculating the refraction - index for X rays EXAFs The Reflection on X Rays Fresnel reflection Reflection from multi-layers Reflection from crystals Reflection and transmission gratings Scattering from surface roughness Geometries for X-Ray Optics The geometric theory of imaging Grazing-incidence telescopes; Walter type I and II and Kirkpatrick-Baez - systems Grating and crystal spectrometers X-Ray Telescopes and Spectrometers Optimization of the design Types of primary X-ray mirror Mirror coatings AXAF and XMM Assessing the performance of X-ray telescopes Future X-ray astronomy missions

Willingale, R.

232

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

233

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

234

MULTI-WAVELENGTH STUDIES OF SPECTACULAR RAM PRESSURE STRIPPING OF A GALAXY: DISCOVERY OF AN X-RAY ABSORPTION FEATURE  

SciTech Connect

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 × 10{sup 20} cm{sup –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 × 10{sup 8} M {sub ?}, 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; Makishima, Kazuo [Research Center for the Early Universe, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)] [Research Center for the Early Universe, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yagi, Masafumi [Optical and Infrared Astronomy Division, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)] [Optical and Infrared Astronomy Division, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Nakazawa, Kazuhiro [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)] [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yoshida, Michitoshi [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)] [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Fujita, Yutaka [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan)] [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan); Hattori, Takashi [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'Ohoku Place, Hilo, HI 96720 (United States)] [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'Ohoku Place, Hilo, HI 96720 (United States); Akahori, Takuya, E-mail: lygu@juno.phys.s.u-tokyo.ac.jp [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)] [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)

2013-11-10

235

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

Microsoft Academic Search

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

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

1997-01-01

236

Multifractal analysis of the microdistribution of elements in sedimentary structures using images from scanning electron microscopy and energy dispersive X ray spectrometry  

Microsoft Academic Search

A novel method for the quantitative characterization of density distributions of elements in sedimentary geosystems is presented. This general technique is based on the multifractal analysis of image-processed elemental maps obtained by scanning electron microscopy combined with energy dispersive X ray spectrometry. Application to microdistributions of Si, Fe, and Al in recent bioactive siliciclastic marine sediments are reported. Inhomogeneous scaling

A. Block; W. von Bloh; T. Klenke; H. J. Schellnhuber

1991-01-01

237

Determination of low levels of transmutation-induced silicon in an aluminium reactor component using X-ray energy dispersive spectrometry  

Microsoft Academic Search

A 1080 grade aluminium reactor component, irradiated to various neutron fluences, has been examined using X-ray energy dispersive spectrometry (XEDS) on scanning and transmission electron microscopes (SEM and TEM) to determine the levels of radiogenic Si. Thermal neutron irradiation resulted in radiogenic Si levels up to 0.64 wt%. Quantitative SEM analysis of XEDS spectra, yielded a precision of 200 ppm,

D. R. G. Mitchell; R. A. Day

1997-01-01

238

Microstructural characterisation of five simulated archaeological copper alloys using light microscopy, scanning electron microscopy, energy dispersive X-ray microanalysis and secondary ion mass spectrometry  

Microsoft Academic Search

This paper describes the microstructural characterisation of five simulated archaeological copper alloys, produced by modern powder technology. The chemical composition of the examined bronzes covers the major families of archaeological bronzes from antiquity until the Roman period. Light microscopy (LM), energy dispersive X-ray microanalysis (EDX), scanning electron microscopy (SEM) as well as two- and three-dimensional secondary ion mass spectrometry (SIMS)

I. Constantinides; M. Gritsch; A. Adriaens; H. Hutter; F. Adams

2001-01-01

239

[Chemical composition analysis of bluish-white porcelain unearthed from Fanchang kiln, Anhui province by wave disperse X-ray fluorescence].  

PubMed

Fanchang kiln was the earliest Chinese bluish-white porcelain kiln which first fired this special porcelain class as early as in Five Dynasties (AD 907-960). However, this important kiln declined rapidly in the middle North Song dynasty (AD 1023-1085). As to the decline reason, it is still not clearly identified till now. In order to find the truth, wavelength-dispersive X-ray fluorescence (WDXRF) was used to determine the elemental abundance patterns of its porcelain bodies in Five Dynasties, the early North Song dynasty and the middle North Song dynasty. The analytical results indicate that the chemical compositions of major, minor and trace elements in porcelain bodies changed greatly in the middle North Song dynasty. Combined with the results of INAA and glaze study, this change in elemental composition should be caused by the change in porcelain raw materials or body-making crafts. Meanwhile, it was just this change that led to the quality decline of raw material and rapid collapse of Fan-chang kiln in the middle North Song dynasty shortly after its establishment. PMID:20939361

Yang, Yu-zhang; Zhang, Ju-zhong; Zan, Yi

2010-08-01

240

X-ray lasing - The diagnostics  

SciTech Connect

High-sensitivity time-resolving x-ray spectrometers were developed for the Novette x-ray laser experiments to distinguish and characterize those x-rays produced by laser activity amidst all the other background radiation. In the microchannel-plate grazing-incidence spectrometer (MCPIGS) x-rays are dispersed according to wavelength by a concave grating into a curved microchannel plate, and the amplified image is mapped flat for photographic recording. Target radiation is detected between 12.5 and 27 nm with 250 ps temporal resolution, high spectral resolution (lambda/Delta lambda = 1800), and a line-radiation detection threshold of 6 x 10 to the -7th J/sr. The transmission-grating streak spectrometer (TGSS) produces an image of the x-ray laser output (with an ellipsoidal mirror) that is separated horizontally into its constituent wavelengths (with a transmission grating) and resolved vertically in time (with a streak caemra). The TGSS has a time resolution of about 40 ps, a spectral resolution of about 0.1 nm, and a collection solid angle of about 1.2 x 10 to the -4th sr.

Not Available

1985-11-01

241

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

NASA Astrophysics Data System (ADS)

Annealed Czochralski Silicon wafers containing SiOx precipitates have been studied by high energy X-ray diffraction in a defocused Laue setup using a laboratory tungsten tube. The energy dispersive evaluation of the diffracted Bragg intensity of the 220 reflection within the framework of the statistical dynamical theory yields the static Debye-Waller factor E of the crystal, which gives access to the strain induced by the SiOx precipitates. The results are correlated with precipitate densities and sizes determined from transmission electron microscopy measurements of equivalent wafers. This allows for the determination of the constrained linear misfit ? between precipitate and crystal lattice. For samples with octahedral precipitates the values ranging from ? = 0.39 (+0.28/-0.12) to ? = 0.48 (+0.34/-0.16) indicate that self-interstitials emitted into the matrix during precipitate growth contribute to the lattice strain. In this case, the expected value calculated from literature values is ? = 0.26 ± 0.05. Further, the precise evaluation of Pendellösung oscillations in the diffracted Bragg intensity of as-grown wafers reveals a thermal Debye-Waller parameter for the 220 reflection B220(293 K) of 0.5582 ± 0.0039 Å2 for a structure factor based on spherically symmetric scattering contributions.

Gröschel, A.; Will, J.; Bergmann, C.; Magerl, A.

2014-06-01

242

Direct Measurement of the Kinetics of Geopolymerisation by in-situ Energy Dispersive X-ray Diffractometry  

SciTech Connect

In-situ energy dispersive X-ray diffractometry (EDXRD) using synchrotron radiation has been used to directly observe the kinetics of formation of a geopolymeric gel from a metakaolin precursor. The use of a purpose-built hydrothermal cell with polychromatic radiation from a wiggler source enables collection of a full diffraction pattern approximately every 150 s. This provides sufficient time resolution to observe the collapse of the metakaolin structure as it dissolves in the activating solution, accompanied by the reprecipitation of the geopolymeric gel binder phase from the now-supersaturated solution. Measurements taken on a limited set of samples of different composition (Si/Al ratio) show a clear trend in the rate of reaction with composition, and also a distinctly different mechanism of reaction in the most highly alkaline systems compared to those containing higher levels of dissolved silica in the activating solution. This corresponds to the results of previous microscopic observations showing significantly different microstructures in these systems, and confirms the value of this technique in analysis of the kinetics of geopolymerisation.

Provis,J.; van Deventer, J.

2007-01-01

243

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

NASA Technical Reports Server (NTRS)

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

1991-01-01

244

In situ energy-dispersive x-ray diffraction system for time-resolved thin-film growth studies  

NASA Astrophysics Data System (ADS)

Energy-dispersive x-ray diffraction (EDXRD) with synchrotron light can be used for in situ-structural analysis during polycrystalline thin-film growth, due to its fast data collection and the fixed diffraction angle. An in situ deposition and analysis set-up for the investigation of nucleation and growth of thin films during magnetron sputtering was constructed and installed at the synchrotron radiation source Hamburger Synchrotronstrahlungs Labor (Hamburg). The polychromatic synchrotron beam passes the sputtering chamber through Kapton windows and hits the substrate with the growing film. The diffracted beam, observed under a fixed diffraction angle of between 1° and 10° was energy-analysed by a high-purity germanium detector. The measurement time for a single XRD spectrum can be as short as 10 s for a beam line at a bending magnet, which allows a time-resolved monitoring of film growth. The performance of the in situ EDXRD set-up is demonstrated for the growth of zinc oxide and tin-doped indium oxide films prepared by reactive magnetron sputtering from ceramic and metallic targets. From the position and the width of the diffraction lines the internal mechanical strain and the grain size of the growing films can be derived. The prospects for thin-film growth investigations using such an instrument are assessed.

Ellmer, K.; Mientus, R.; Weiß, V.; Rossner, H.

2003-03-01

245

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

246

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

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

247

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

PubMed Central

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

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

2013-01-01

248

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

Microsoft Academic Search

An analysis is given of the rate at which photons are incident on a sample in a diamond anvil high-pressure cell, from a conventional, fixed-anode source, and a synchrotron source. Comparison is then made of the rate at which photons can be detected for an energy-dispersive diffraction experiment. The rate at which photons are detected in synchrotron experiments is limited

Ian L. Spain; David R. Black

1985-01-01

249

X-ray energy dispersive spectroscopy of uranium ore using a TES microcalorimeter mounted on a field-emission scanning electron microscope  

NASA Astrophysics Data System (ADS)

Energy dispersive spectroscopic measurements of uranium ore were conducted using a superconducting phase transition-edge-thermosensor (TES) microcalorimeter mounted on a field-emission scanning electron microscope (SEM) to demonstrate its potential for high-precision microanalysis. The effective solid angle for X-ray detection is found to be larger than 2 msr by precise adjustments in the X-ray polycapillary alignment. The observed detection signal pulses with decay time constant of 50 ?s enable maximum count rates larger than 300 counts per second. The energy resolution was determined to be 14.6 eV FWHM at Al K? X-ray energies of 1487 eV. Distinct peaks appear in the resulting X-ra y energy spectrum associated with U-M?, U-M? and U-M? X-rays emitted by the uranium ore specimens. This spectrum includes weaker peaks corresponding to C-K?, Fe-L?, Cu-L and Sr L ? X rays.

Maehata, Keisuke; Idemitsu, Kazuya; Tanaka, Keiichi

2011-08-01

250

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

251

In Situ High Pressure Angle Dispersive X-ray Diffraction Experiments:With Sagittally-Bent Double Laue Monochomator  

Microsoft Academic Search

A Sagittally-bent double Laue monochomator is used at the wiggler beam line X17C of NSLS, BNL. It can provide high-energy X-ray tunable from 20 keV to 40 keV. The monochomator consists of two Si crystals of 0.76 mm thick, with surface corresponding to the (001) planes. The 111 reflections of both crystals are used to diffract the x-ray. The two

J. Hu; Z. Zhong; H. Liu; Q. Guo; H. Mao; R. J. Hemley

2003-01-01

252

Simulation of an energy-dispersion x-ray spectrometer in the computational medium X-Energo  

SciTech Connect

The description of the calculation part of the simulation medium X-Energo is presented. It contains mathematical models included in the medium X-Energo for the determinating major processes taking place in an X-ray spectrometer, namely, the formation of an X-ray radiation spectrum, the interaction of this radiation with filter and sample materials, and the detector response to the signal. 6 refs.

Plotnikov, R.I.; Savel`ev, S.K.; Fedorov, S.I. [Baltic State Technical Univ., St. Petersburg (Russian Federation)

1995-01-01

253

SO2Cl2, SOCl2: energy dispersive X-ray diÄraction, 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 diÄraction). The Lennard- Jones (L-J) parameters of the force field (FF) fit satisfactorily the X-ray diÄraction 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

254

Determination of rare earth elements and thorium in britholite ore by energy dispersive X-ray fluorescence spectrometry  

Microsoft Academic Search

A radioisotope-excited X-ray fluorescence technique is applied for the determination of thorium and rare earth elements in britholite ore from Canada. An annular source of57Co is employed for excitation of characteristic K X-rays of thorium and rare earth elements. The peak ratios of lanthanides were used to remove the difficulties because of overlapping lines at the 33–50 keV energy region.

N. Efe; S. Akman; P. Arikan

1987-01-01

255

Characterization of the interfacial geomechanics in gas shales via integrated Raman spectroscopy, nanoindentation and energy dispersive X-ray spectroscopy  

NASA Astrophysics Data System (ADS)

The geomechanical characterization of gas shales at the microscale is currently enabled by the use of grid-based nanoindentation techniques. However, the inability to probe the chemical and mineral heterogeneity of gas shales limits the identification of the geomechanical properties of individual components and phases within the probed region. The development of an integrated multiphysics approach that combines geomechanical and chemical information is crucial for the characterization of interfaces between phases, leading to the identification of regions with low yield strain. Here we present a comprehensive investigation where a spatially aligned coupled multiphysics analysis of gas shales is used to identify relevant the geomechanics of mineral and organic phases and their interfaces. This method uses grid-based nanondentation to extract the geomechanical information. Raman spectroscopy is used to identify the majority of inorganic components (calcite, quartz, anatase, pyrite, clay) as well as to characterize the diversity and maturity in the organic component (kerogen). Energy dispersive X-ray is used in combination with Raman to identify clay. With the use of clustering analysis statistical tools a correlation analysis over the full range of data (geomechanics and chemical data), we identify several mineral phases, and we clearly associate the mechanical properties (defined in terms of hardness, modulus and yield strain) with each phase. With this innovative multiphysics analysis we were able to identify interfacial phases between inorganic phases, with distinct hardness and yield strain. We find that regions between calcite-rich or quartz rich phases and clay-rich phases showed a lower than of that of the corresponding boundary phases. Hence this approach provides a viable method for the identification of the "weakest links" in gas shales with the highest probability of fracture.

Ferralis, N.; Abedi, S.; Grossman, J. C.; Ulm, F.

2012-12-01

256

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

257

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

258

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

259

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

260

Fusion peptides promote formation of bilayer cubic phases in lipid dispersions. An x-ray diffraction study.  

PubMed

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

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

2013-03-01

261

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

Microsoft Academic Search

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

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

2003-01-01

262

The application of energy-dispersive x-ray fluorescence spectrometry (EDXRF) to the analysis of cosmetic evidence in Indian nail polishes.  

PubMed

The application of energy-dispersive x-ray fluorescence (EDXRF) spectrometry in the quantitative analysis of samples of Indian nail polishes of apparently similar shades from different manufacturers has been examined by evaluating the possibility of detecting spurious material which is marketed under the guise of a popular brand. On the basis of the number of elements detected, and from the ratios of particular elements [Fe/Ti, Fe/Cu, Ti/Cu] the results are very encouraging. PMID:1325419

Misra, G; Sawhney, K J; Lodha, G S; Mittal, V K; Sahota, H S

1992-05-01

263

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

SciTech Connect

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

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

1983-01-01

264

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

265

Elemental relationships in rock varnish as seen with SEM\\/EDX (scanning electron microscopy\\/energy dispersive x-ray) elemental line profiling  

Microsoft Academic Search

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

R. Jr. Raymond; S. L. Reneau; C. D. Harrington

1990-01-01

266

Complementary analysis of historical glass by scanning electron microscopy with energy dispersive X-ray spectroscopy and laser ablation inductively coupled plasma mass spectrometry  

Microsoft Academic Search

.  Laser ablation inductively coupled plasma mass spectrometry (LA ICP MS) was used as a supporting method for elemental analysis\\u000a of historical glass investigated by means of scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM\\/EDS).\\u000a Investigated objects represent mainly late- and post-medieval glass objects (mostly Façon-de-Venise vessels and nuppenbechers), window glass and chandeliers from excavation in Elbl?g, Pozna? and Wroc?aw

Barbara Wagner; Anna Nowak; Ewa Bulska; Jerzy Kunicki-Goldfinger; Olivier Schalm; Koen Janssens

2008-01-01

267

Automatic Peak Identification in Scanning Electron Microscopy\\/Energy Dispersive X-ray (SEM\\/EDS) Microanalysis: Can You Always Trust the Results?  

Microsoft Academic Search

The degree of sophistication of computer-aided scanning electron microscopy\\/energy dispersive x-ray spectrometry (SEM\\/EDS) microanalysis has advanced to the point where it is possible with a single command to automatically perform sequential qualitative analysis (peak identification) and quantitative analysis and then create a report of analysis with full statistical support. Often the actual algorithms employed in commercial software for each stage

D. Newbury

2006-01-01

268

Scanning electron microscopy and energy-dispersive X-ray analysis of self-etching adhesive systems to ground and unground enamel  

Microsoft Academic Search

The morphological analysis of the ground and unground enamel was treated with three different self-etching adhesive systems.\\u000a Ultrastructural features were observed by using the field emission scanning electron microscope (FESEM) in combination with\\u000a Energy Dispersive X-Ray Spectroscopy (EDS) analysis. Thirty extracted human molars were used for this study. Teeth were divided\\u000a into two groups. In the first group unground enamel

Dinesh D. S. Weerasinghe; Toru Nikaido; Shizuko Ichinose; Kanchana G. P. Waidyasekara; Junji Tagami

2007-01-01

269

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

270

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

271

In-situ energy-dispersive X-ray diffraction of metal sulfide assisted crystallization of strongly (001) textured photoactive tungsten disulfide thin films  

Microsoft Academic Search

Highly (001) textured tungsten disulphide (WS2) thin films were grown by rapid metal (Ni, Pd) sulfide assisted crystallization of amorphous reactively sputtered sulfur-rich tungsten sulfide (WS3+x) and by metal sulfide assisted sulfurization of tungsten metal films. The rapid crystallization was monitored by real-time in-situ energy dispersive X-ray diffraction (EDXRD). Provided that a thin nickel or palladium film was deposited prior

S. Brunken; R. Mientus; K. Ellmer

2009-01-01

272

Transmission electron microscopy and energy dispersive X-ray spectroscopy on the worn surface of nano-structured TiAlN\\/VN multilayer coating  

Microsoft Academic Search

Nano-structured TiAlN\\/VN multilayer hard coatings grown by cathodic arc metal ion etching and unbalanced magnetron sputtering deposition have repeatedly shown low coefficients of friction and wear. In this paper, we employed the combined methods of cross-sectional ion beam milling sample preparation, conventional transmission electron microscopy, energy dispersive X-ray spectroscopy and quantitative spectrum analysis to give a comprehensive characterization of wear

Q. Luo; P. Eh. Hovsepian

2006-01-01

273

Understanding the limitations of the Super-X energy dispersive x-ray spectrometer as a function of specimen tilt angle for tomographic data acquisition in the S/TEM  

NASA Astrophysics Data System (ADS)

We have investigated the use of x-ray energy dispersive spectroscopy during tomographic hyperspectral imaging experiments in the scanning transmission electron microscope. In this work, we have found that for an analytical system employing a commercial high-tilt tomography holder the measured x-ray signal is limited by shadowing caused by the penumbra of the holder relative to the x-ray detector system. This limits the ability to perform quantitative, elemental tomographic analysis.

Slater, T. J. A.; Camargo, P. H. C.; Burke, M. G.; Zaluzec, N. J.; Haigh, S. J.

2014-06-01

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

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

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

X-ray imaging and x-ray source development at Lawrence Livermore National Laboratory  

SciTech Connect

The Laser Program at Lawrence Livermore National Laboratory has a continuing effort to develop both x-ray sources and x-ray sources and x-ray microscopy. This effort includes the ongoing development of: (1) a wide range of x-ray lasers at the Nova Laser Facility, (2) a zone plate lens--multilayer mirror based x-ray microscope (3) three dimensional, high resolution x-ray microscopy (4) short wavelength, normal incidence multilayer x-ray mirrors, (5) compact, high average power lasers for producing x-ray lasers and laser plasma x-ray sources. We have constructed and operated an x-ray laser based transmission x-ray microscope. The advantage offered by the x-ray laser source is the extreme high brightness allows high resolution images to be made on a timescale faster than that for x-ray damage effects to appear. The microscope, consists of: the x-ray laser, a multilayer coated, near normal incidence spherical mirror used as a condenser, a silicon nitride specimen holder, an x-ray zone plate used as an objective lens, and a microchannel plate x-ray detector. The x-ray laser used is the Ni-like Ta x-ray laser operating with a wavelength of 4.48 nm, a pulselength of 200 spec, a divergence of 10 mrad, and an output energy of 10 microjoules.

Trebes, J.; Balhorn, R. [Lawrence Livermore National Lab., CA (United States); Anderson, E. [Lawrence Berkeley Lab., CA (United States)] [and others

1993-12-01

278

Measurement of Titanium Dioxide in Cosmetic Products with X-Ray Fluorescence Spectrometry  

Microsoft Academic Search

This paper reports the development of a simple method for measuring titanium dioxide in cosmetic products using X-ray fluorescence. A sample is prepared by stirring in a dispersion medium and then filtering with a 0.1 ?m pore size membrane filter. The titanium dioxide particles trapped on the dried membrane filter are then measured with a wave-length dispersive X-ray fluorescence spectrometer.

Akihiko Kawauchi; Masahiro Ishida; Ikuko Saitoh

1996-01-01

279

Building X-ray lasers  

NASA Astrophysics Data System (ADS)

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

2010-12-01

280

A study of X-ray emission from galactic and extragalactic sources with emphasis on soft and ultra-soft wavelengths  

NASA Technical Reports Server (NTRS)

A Black Brant VC rocket was used to scan the Coma and Virgo clusters in order to measure structure in the X-ray sources. The rocket also made measurements of soft X-ray spectra, soft X-ray background flux during a 50 deg scan of the sky, soft X-rays from De Voucoulers 50, set limits to the energy dependence of soft X-ray background spectra, and the flux of solar 584 A radiation resonantly scattered by interstellar He flowing through the solar system.

Bowyer, C. S.; Lampton, M.; Cruddace, R. G.; Paresce, F.

1974-01-01

281

An analytic model for the response of a CZT detector in diagnostic energy dispersive x-ray spectroscopy  

SciTech Connect

A CdZnTe detector (CZTD) can be very useful for measuring diagnostic x-ray spectra. The semiconductor detector does, however, exhibit poor hole transport properties and fluorescence generation upon atomic de-excitations. This article describes an analytic model to characterize these two phenomena that occur when a CZTD is exposed to diagnostic x rays. The analytical detector response functions compare well with those obtained via Monte Carlo calculations. The response functions were applied to 50, 80, and 110 kV x-ray spectra. Two 50 kV spectra were measured; one with no filtration and the other with 1.35 mm Al filtration. The unfiltered spectrum was numerically filtered with 1.35 mm of Al in order to see whether the recovered spectrum resembled the filtered spectrum actually measured. A deviation curve was obtained by subtracting one curve from the other on an energy bin by bin basis. The deviation pattern fluctuated around the zero line when corrections were applied to both spectra. Significant deviations from zero towards the lower energies were observed when the uncorrected spectra were used. Beside visual observations, the exposure obtained using the numerically attenuated unfiltered beam was compared to the exposure calculated with the actual filtered beam. The percent differences were 0.8% when corrections were applied and 25% for no corrections. The model can be used to correct diagnostic x-ray spectra measured with a CdZnTe detector.

LeClair, Robert J.; Wang Yinkun; Zhao Peiying; Boileau, Michel; Wang, Lilie; Fleurot, Fabrice [Department of Physics and Astronomy, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada) and Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada); Department of Physics and Astronomy, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada)

2006-05-15

282

On the use of polycapillary structures to improve laboratory Energy-Dispersive X-ray Diffractometry and Reflectometry  

Microsoft Academic Search

One of the major limits of the laboratory X-ray sources is represented by their low photon flux which induces many researchers to move to synchrotron beamlines. From this point of view, polycapillaries lenses represent an extraordinary tool to improve the performances of laboratory machine and, indeed, several models of polycapillary optics-based instruments, such as diffractometers, spectrometers etc., are currently available

V. Rossi Albertini; B. Paci; A. Generosi; S. B. Dabagov; O. Mikhin; M. A. Kumakhov

2007-01-01

283

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...

284

Electrode structures in diode-type cadmium telluride detectors: Field emission scanning electron microscopy and energy-dispersive x-ray microanalysis  

SciTech Connect

The structures of the interface regions between CdTe crystal and electrodes in diode-type CdTe x-ray detectors with a layout of In(anode)/CdTe/Pt(cathode) are reported. The structures have been investigated by field emission scanning electron microscopy and energy-dispersive x-ray microanalysis. The investigation has revealed that the structures are complicated. The anode-side interface is a contact between In{sub 1-x}Te{sub x} alloys and CdTe crystal. The cathode side is a structure of Pt/(Te-rich phase)/CdTe. These findings suggest that the complicated structures in the interface regions are a possible cause for the polarization phenomenon observed in the diode-type CdTe detectors.

Okada, Kyoko; Yasufuku, Hideyuki; Yoshikawa, Hideki; Sakurai, Yoshiharu [Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); National Institute for Materials Science (NIMS), 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

2008-02-18

285

Temperature-dependent structure of liquid water investigated by means of energy-dispersive x-ray diffraction and molecular dynamics simulations  

NASA Astrophysics Data System (ADS)

X-ray diffraction is investigated in the supercooled region (263-273 K) and, for comparison, at ambient conditions. By means of an energy-dispersive set-up coherent x-ray scattering cross sections within a wide range of momentum transfer values are monitored simultaneously using in-house laboratory equipment. The data are corrected for the energy-dependent detector response, geometric broadening effects, sample absorption and Compton scattering. The corrected diffraction curves are in good agreement with results from the Advanced Light Source (ALS). Additional comparisons with available literature data and with computer simulation results of different rigid water models are presented, relating the scattering intensities to the microscopic H-bond structure and dynamics.

Guse, C.; Simionescu, A.; Schünemann, B.; Hentschke, R.; Bomsdorf, H.

2010-08-01

286

RF Single Electron Transistor Readout Amplifiers for Superconducting Astronomical Detectors for X-Ray to Sub-mm Wavelengths  

NASA Technical Reports Server (NTRS)

We report progress on using a new type of amplifier, the Radio-Frequency Single-Electron Transistor (RF-SET), to develop multi-channel sensor readout systems for fast and sensitive readout of high impedance cryogenic photodetectors such as Superconducting Tunnel Junctions and Single Quasiparticle Photon Counters. Although cryogenic, these detectors are desirable because of capabilities not other-wise attainable. However, high impedances and low output levels make low-noise, high-speed readouts challenging, and large format arrays would be facilitated by compact, low-power, on-chip integrated amplifiers. Well-suited for this application are RF-SETs, very high performance electrometers which use an rf readout technique to provide 100 MHz bandwidth. Small size, low power, and cryogenic operation allow direct integration with detectors, and using multiple rf carrier frequencies permits simultaneous readout of 20-50 amplifiers with a common electrical connection. We describe both the first 2-channel demonstration of this wavelength division multiplexing technique for RF-SETs, and Charge-Locked-Loop operation with 100 kHz of closed-loop bandwidth.

Stevenson, Thomas; Aassime, Abdelhanin; Delsing, Per; Frunzio, Luigi; Li, Li-Qun; Prober, Daniel; Schoelkopf, Robert; Segall, Ken; Wilson, Chris; Stahle, Carl

2000-01-01

287

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

Microsoft Academic Search

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

Loïc Perring; Joëlle Blanc

2008-01-01

288

Determination of iron and titanium in kaolins by the method of non-dispersive X-ray fluorescence  

Microsoft Academic Search

The possibility of application of the radioactive source excited X-ray fluorescence analysis for titanium and iron determination\\u000a in kaolins to the routine test of the refinement process has been studied. The iron content can be determined with a simple\\u000a counting system using a single-channel pulse height analyser, argon filled proportional counter and109Cd source of 3 mCi for the excitation of

J. Kierzek; J. Parus

1976-01-01

289

ArtTAX--a new mobile spectrometer for energy-dispersive micro X-ray fluorescence spectrometry on art and archaeological objects.  

PubMed

A newly developed spectrometer for energy-dispersive micro X-ray fluorescence spectrometry has been designed for the demands of archaeometry. ArtTAX combines the advantages of non-destructive and sensitive multi-elemental analysis at sub-mm resolution with the possibility of working outside the laboratory. The spectrometer consists of an air-cooled, low-power molybdenum tube, new generation polycapillary X-ray optics, a silicon drift detector without the need for liquid-nitrogen cooling, a CCD camera, and three light diodes for sample positioning. The motor-driven measurement head is fixed on a x,y,z-flexible tripod support which can be assembled and dismantled within minutes. The spot size of the primary X-ray beam was determined to be 94 microm for the Cu(Kalpha) energy, the detection limits are in a range of a few tens of microg g(-1) for the medium energy-range in glass. Additional open helium purging in the excitation and detection paths enables the determination of elements down to sodium, thus avoiding vacuum conditions or a size-limiting sample chamber. A selection of qualitative and quantitative results on pigment, metal, glass, and enamel analyses are presented to show the potential of ArtTAX in the field of art and archaeology. PMID:11688642

Bronk, H; Röhrs, S; Bjeoumikhov, A; Langhoff, N; Schmalz, J; Wedell, R; Gorny, H E; Herold, A; Waldschläger, U

2001-10-01

290

An energy-dispersive X-ray diffraction study of the nickel-sulfide assisted growth of RuS2 thin films by reactive magnetron sputtering  

NASA Astrophysics Data System (ADS)

RuS2 thin films were deposited by reactive magnetron sputtering from a metallic Ru target in an Ar/H2S atmosphere. The influence of Ni sputtering on the crystalline properties of the deposited RuS2 was observed in real-time using in-situ energy-dispersive X-ray diffraction (EDXRD) by which it was possible to take an X-ray diffraction and fluorescence pattern every 10 s. Co-sputtering from a Ni target as well as pre-deposition of NiSx leads to an improved growth of the RuS2 crystallites. The size of the RuS2 crystallites increases with additional sputtering of Ni, which was proved by X-ray diffraction and scanning electron microscopy. Above deposition temperatures of about 673 K only the Ru phase grows without Ni assistance. Co-sputtering of Ni leads to the growth of RuS2 even at temperatures of 773 K. Thus using Ni allows higher deposition temperatures, which further improves the crystalline properties of RuS2 films.

Brunken, Stephan; Krause, Jonas; Ellmer, Klaus

2013-01-01

291

Pre-Columbian alloys from the royal tombs of Sipán; energy dispersive X-ray fluorescence analysis with a portable equipment.  

PubMed

On the north coast of present-day Peru flourished approximately between 50 and 700 AD, the Moche civilization. It was an advanced culture and the Moche were sophisticated metalsmiths, so that they are considered as the finest producers of jewels and artefacts of the region. The Moche metalworking ability was impressively demonstrated by the objects discovered by Walter Alva and coworkers in 1987, in the excavations of the "Tumbas Reales de Sipán". About 50 metal objects from these excavations, now at the namesake Museum, in Lambayeque, north of Peru, were analyzed with a portable equipment using energy-dispersive X-ray fluorescence. This portable equipment is mainly composed of a small size X-ray tube and a thermoelectrically cooled X-ray detector. Standard samples of gold and silver alloys were employed for quantitative analysis. It was determined that the analyzed artefacts from the "Tumbas Reales de Sipán" are mainly composed of gold, silver and copper alloys, of gilded copper and of tumbaga, the last being a poor gold alloy enriched at the surface by depletion gilding, i.e. removing copper from the surface. PMID:19819709

Cesareo, R; Calza, C; Dos Anjos, M; Lopes, R T; Bustamante, A; Fabian S, J; Alva, W; Chero Z, L

2010-01-01

292

Anomalous Dispersion of Longitudinal Optical Phonons in Nd1.86Ce0.14CuO4+? Determined by Inelastic X-Ray Scattering  

Microsoft Academic Search

The phonon dispersions of Nd1.86Ce0.14CuO4+? along the (?,0,0) direction have been determined by inelastic x-ray scattering. Compared to the undoped parent compound, the two highest longitudi- nal phonon branches, associated with the Cu-O bond-stretching and out-of-plane oxygen vibration, are shifted to lower energies. Moreover, an anomalous softening of the bond-stretching band is ob- served around q = (0.2,0,0). These signatures

M. d'Astuto; P. K. Mang; P. Giura; A. Shukla; P. Ghigna; A. Mirone; M. Braden; M. Greven; M. Krisch; F. Sette

2002-01-01

293

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

294

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

295

Feasibility for direct rapid energy dispersive X-ray fluorescence (EDXRF) and scattering analysis of complex matrix liquids by partial least squares.  

PubMed

The greatest challenge to material characterization by XRF technique is encountered in direct trace analysis of complex matrices. We exploited partial least squares (PLS) in conjunction with energy dispersive X-ray fluorescence and scattering (EDXRFS) spectrometry to rapidly (200 s) analyze lubricating oils. The PLS-EDXRFS method affords non-invasive quality assurance (QA) analysis of complex matrix liquids as it gave optimistic results for both heavy- and low-Z metal additives. Scatter peaks may further be used for QA characterization via the light elements. PMID:22940413

Angeyo, K H; Gari, S; Mustapha, A O; Mangala, J M

2012-11-01

296

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

297

Effect of hydration on the long-range order of lipid multilayers investigated by in situ time-resolved energy dispersive X-ray diffraction  

NASA Astrophysics Data System (ADS)

In situ time-resolved energy dispersive X-ray diffraction (EDXD) was applied to investigate the hydration kinetics of oriented dioleoylphosphocoline (DOPC) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) membranes. The long-range order in the investigated lipid multilayers has been found to vary as a function of hydration in a nonmonotic way. In the first stage, water adsorption increased the long-range order along the normal to the lipid bilayer whereas, in the second one, a progressive loss of interbilayer coherence was observed. Possible molecular mechanisms underlying the experimental observations are discussed.

Caminiti, Ruggero; Caracciolo, Giulio; Pisani, Michela; Bruni, Paolo

2005-06-01

298

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

NASA Astrophysics Data System (ADS)

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

2005-06-01

299

Reflectivity measurements in the vacuum ultraviolet wavelength range on technical surfaces for the Wolter I telescope on board the X-ray astronomy satellite ROSAT  

NASA Astrophysics Data System (ADS)

The results of reflectivity measurements in the vacuum ultraviolet wavelength region (VUV) on technical surfaces are described which are used in the Wolter I-telescope on board the German X-ray astronomy satellite ROSAT. The materials investigated are the special iron-nickel alloy Invar and a carbon fibre compound (CFK). The centre connecting flange for the parabolic and hyperbolic mirror sections of the telescope is made of Invar. CFK is used for the thermal baffle in front of the telescope. It had to be checked whether the structure of the centre flange and the thermal baffle sufficiently suppress scattered ultraviolet radiation in order to avoid a substantial background level in the detectors which are located in the focal plane of the telescope. The detectors consist of two positional sensitive proportional counters (PSPC) with a spatial resolution of 0.5 arc mm and an image converter with a resolution of a few arc sec. The detectors are mounted on a carrousel platform and are intended to be positioned alternatively in the focal plane

Stephan, K. H.; Braeuninger, H.; Kaase, H.; Metzdorf, J.

1986-08-01

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

2013-06-01

301

The Crystal Structure of Sb 0.92V 0.92O 4, Determined by Neutron and Dual Wavelength X-Ray Powder Diffraction  

NASA Astrophysics Data System (ADS)

A phase of approximate composition SbVO 4 has been reported in the literature as a key component in new catalysts for the ammoxidation of propane to acrylonitrile. Sb 0.92V 0.92O 4 was prepared by heating equimolar amounts of Sb 2O 3 and V 2O 5 in air at 1073 K for 2 hr. The chemical composition was determined by thermogravimetry and energy dispersive X-ray microanalysis. The crystal structure at 293 K was determined, from three powder diffraction data sets recorded with Cu K? 1, Mo K?, and 1.040(1)-Å neutron radiation, using the Rietveld method. Crystal data: Sb 0.92V 0.92O 4, Z = 1, a = 4.625(4), c = 3.040(2) Å, tetragonal space group P 4 2/mnm, M r = 222.87, Dcalc = 5.69 g/cm 3. All three data sets yield a cation deficient rutile structure and final profile R-values of 3.5, 6.3, and 3.5%. Bond valence sums, calculated from the experimentally determined bond lengths, indicate the oxidation states to be Sb 5+ and V 3+/V 4+, leading to the formula Sb 5+0.92V 3+0.28V 4+0.64? 0.16O 4 (the square denotes metal ion vacancies). Bond valence calculations also suggest that OSb 2? is the most favorable configuration for an oxygen associated with a metal vacancy.

Hansen, Staffan; Ståhl, Kenny; Nilsson, Roland; Andersson, Arne

1993-02-01

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  

NASA Astrophysics Data System (ADS)

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 ?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.

2003-01-01

304

Thermal and Structural Behavior of Dioctadecyldimethylammonium Bromide Dispersions Studied by Differential Scanning Calorimetry and X-Ray Scattering  

PubMed Central

Dioctadecyldimethylammonium bromide (DODAB) is a double chain cationic lipid, which assembles as bilayer structures in aqueous solution. The precise structures formed depend on, e.g., lipid concentration and temperature. We here combine differential scanning calorimetry (DSC) and X-ray scattering (SAXS and WAXS) to investigate the thermal and structural behavior of up to 120 mM DODAB in water within the temperature range 1–70°C. Below 1 mM, this system is dominated by unilamellar vesicles (ULVs). Between 1 and 65 mM, ULVs and multilamellar structures (MLSs) co-exist, while above 65 mM, the MLSs are the preferred structure. Depending on temperature, DSC and X-ray data show that the vesicles can be either in the subgel (SG), gel, or liquid crystalline (LC) state, while the MLSs (with lattice distance d ?=?36.7 Å) consist of interdigitated lamellae in the SG state, and ULVs in the LC state (no Bragg peak). Critical temperatures related to the thermal transitions of these bilayer structures obtained in the heating and cooling modes are reported, together with the corresponding transition enthalpies.

Feitosa, Eloi; Adati, Renata D.; Hansson, Per; Malmsten, Martin

2012-01-01

305

Determination of Tin in Canned Foods by X-Ray Fluorescence Spectrometry  

Microsoft Academic Search

Wavelength-dispersive X-ray fluorescence spec- trometry following a simple pretreatment was devel- oped to determine levels of dissolved tin in canned foods. Sample syrup or a homogenate solution of fruit (meat) was freeze-dried and diluted with the same weight of cellulose powder. The mixed powder was then quickly formed into a pellet for X-ray measurements. This analytical method (detection limit, 5

Yoshiki Mino

2006-01-01

306

Characterization of titanium nitride layers by grazing-emission X-ray fluorescence spectrometry  

Microsoft Academic Search

Grazing-emission X-ray fluorescence spectrometry is a new development in X-ray metrology instrumentation. The combination of wavelength-dispersive detection with a total-reflection geometry in the detection path allows thin layer characterization also for light elements. The technique was applied to analyze a series of titanium nitride layers, reactively sputtered using different ArN2 flow ratios of the working gas. Composition, thickness and density

G. Wiener; S. J. Kidd; C. A. H. Mutsaers; R. A. M. Wolters; P. K. de Bokx

1998-01-01

307

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

NASA Astrophysics Data System (ADS)

The intermetallic compounds Mg 2Si, MoSi 2, WSi 2, CrSi 2, NbSi 2, Ti 5Si 3, TiSi 2, ZrSi 2 and Al 3Nb 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 transition of cubic Mg 2Si to a hexagonal phase was observed at 70 kbar and 450°C. The high-pressure/high-temperature phase was quenched and recovered for further investigations. All the other compounds remained stable in the mentioned pressure and temperature range. The bulk moduli covered the range from 436 (10) (Mg 2Si) to 3350 (190) (WSi 2) kbar.

Peun, T.; Lauterjung, J.; Hinze, E.

1995-05-01

308

Polycapillary X-Ray Optics for X-Ray Astronomy  

NASA Technical Reports Server (NTRS)

High-energy x-ray spectrometry from astronomical sources is difficult due to low flux rates and high background. Polycapillary x-ray optics can be used to increase the signal-to-noise ratio by focusing photons onto a small energy dispersive detector. Two optics, both designed for x-ray astronomy, have been built and tested as collimating optics with a microfocus x-ray source for x-ray energies up to 70 keV and as focusing optics with parallel x-rays up to 50 keV. Results from these tests show that polycapillary x-ray optics have transmission efficiencies ranging from 5% to 40% and signal gains ranging from 5 to over 100 for energies up to 50 keV. Furthermore the results show that these optics have potential for use up to 100 keV. The experimental results as well as simulations for the measured and for optimized optics will be discussed.

Russell, C. H.; Gubarev, M.; Kolodziejczak, J.; Joy, M.; MacDonald, C. A.; Gibson, W. M.

1999-01-01

309

X-Ray Binaries  

NASA Astrophysics Data System (ADS)

The extreme conditions existing in the near vicinity of neutron stars which are the secondaries in close binaries provide a laboratory in which we may observationally confirm or refine many of our basic theories of astrophysics. This program will monitor the photometric and polarimetric light curves of X-ray binaries at several different phases of the binary orbit in several different wavelength bands in the UV. The results will be related to the structure of, and physical conditions existing in, the gas streams (and possibly, the accretion disk) in these systems. Revision History (4036): Prepared for augmentation submission--Dolan 5/8/92;

Bless, Robert

1992-07-01

310

SMM x ray polychromator  

NASA Technical Reports Server (NTRS)

The objective of the X-ray Polychromator (XRP) experiment was to study the physical properties of solar flare plasma and its relation to the parent active region to understand better the flare mechanism and related solar activity. Observations were made to determine the temperature, density, and dynamic structure of the pre-flare and flare plasma as a function of wavelength, space and time, the extent to which the flare plasma departs from thermal equilibrium, and the variation of this departure with time. The experiment also determines the temperature and density structure of active regions and flare-induced changes in the regions.

Saba, J. L. R.

1993-01-01

311

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

312

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

313

X-Rays  

MedlinePLUS

X-rays are a type of radiation called electromagnetic waves. X-ray imaging creates pictures of the inside of ... different amounts of radiation. Calcium in bones absorbs x-rays the most, so bones look white. Fat ...

314

Optimum amplifier location for wavelength division multiplexed dispersion managed solitons  

NASA Astrophysics Data System (ADS)

Using a variational method, we analyze the residual frequency shifts due to cross-channel interactions in wavelength division multiplexed dispersion managed soliton transmission systems. We put forward a simple criterion for the optimal location of the amplifier based on the results of this analysis. This conclusion is explained in terms of the dependence of the propagation properties of a single pulse on the position of the amplifier and the optimality of the criterion is assessed, for some specific parameter values, using a commercial simulation software.

Diaz-Otero, Francisco J.; Chamorro-Posada, Pedro

2012-10-01

315

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

316

Study of trace element correlations with drought tolerance in different sorghum genotypes using energy-dispersive X-ray fluorescence technique.  

PubMed

Drought-tolerant and drought-susceptible genotypes of sorghum (Sorghum bicolor L. Monech) were analyzed by the energy-dispersive X-ray fluorescence (EDXRF) technique to study the correlation of trace elements with drought-tolerance capacities. Samples prepared from mature seeds, young seedlings, and old plants were analyzed using a 109Cd radioisotope source and a Si(Li) semiconductor detector of resolution 170 eV for 5.9-keV MnKalpha X-rays. Elements such as K, Fe, Cu, Zn, Rb and Sr and Y were found to be present in varying concentrations in different samples. The trace element profile studied in the seeds of 11 genotypes and in seedlings (young and old) of 4 sorghum genotypes showed considerable variation. The genotype Arfa Gadamak (AG) showed a distinct presence of a high level of Zn in its young seedling. It was observed that in most of the genotypes (seeds), K and Fe concentrations were more in the tolerant genotype as compared to the susceptible type. The concentration of Fe decreased with maturity in the tolerant group and it increased with maturity in the susceptible group. PMID:11934249

Abu, Assar A H; Joseph, Daisy; Suprasanna, P; Choudhury, R K; Saxena, A; Bapat, V A

2002-03-01

317

High-throughput and time-resolved energy-dispersive X-ray diffraction (EDXRD) study of the formation of CAU-1-(OH)2: microwave and conventional heating.  

PubMed

Aluminium dihydroxyterephthalate [Al(8)(OH)(4)(OCH(3))(8)(BDC(OH)(2))(6)]?x?H(2)O (denoted CAU-1-(OH)(2)) was synthesized under solvothermal conditions and characterized by X-ray powder diffraction, IR spectroscopy, sorption measurements, as well as thermogravimetric and elemental analysis. CAU-1-(OH)(2) is isoreticular to CAU-1 and its pores are lined with OH groups. It is stable under ambient conditions and in water, and it exhibits permanent porosity and two types of cavities with effective diameters of approximately 1 and 0.45 nm. The crystallization of CAU-1-(OH)(2) was studied by in situ energy-dispersive X-ray diffraction (EDXRD) experiments in the 120-145 °C temperature range. Two heating methods-conventional and microwave-were investigated. The latter leads to shorter induction periods as well as shorter reaction times. Whereas CAU-1-(OH)(2) is formed at all investigated temperatures using conventional heating, it is only observed below 130 °C using microwave heating. The calculation of the activation energy of the crystallization of CAU-1-(OH)(2) exhibits similar values for microwave and conventional synthesis. PMID:21538608

Ahnfeldt, Tim; Moellmer, Jens; Guillerm, Vincent; Staudt, Reiner; Serre, Christian; Stock, Norbert

2011-05-27

318

The Diffuse X-ray Spectrometer Experiment  

NASA Astrophysics Data System (ADS)

The Diffuse X-ray Spectrometer Experiment, or 'DXS', is designed to measure the spectrum of the low-energy diffuse X-ray background with about 10 eV energy resolution and 15-deg spatial resolution. During a 5-day Space Shuttle mission, DXS is to measure the spectrum of ten 15 x 15 deg regions lying along a single 150-deg-long great circle arc on the sky. DXS carries two large-area X-ray Bragg spectrometers for the 44-84 A wavelength range; these permit measurement of the wavelength spectrum of the cosmic low-energy diffuse X-ray background with good spectral resolution.

Sanders, W. T.; Edgar, R. J.; Juda, M.; Kraushaar, W. L.; McCammon, D.; Snowden, S. L.; Zhang, J.; Skinner, M. A.

1992-10-01

319

X-ray fluorescence analysis major elements in silicate minerals  

Microsoft Academic Search

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

Hagan

1982-01-01

320

Determination of heavy metals in suspended waste water collected from Oued El Harrach Algiers River by Energy Dispersive X-Ray Fluorescence  

NASA Astrophysics Data System (ADS)

A preliminary study of the atmospheric pollution in the centre of Algiers is one of the important fields of applications in the environmental science. Nowadays, we need to evaluate the level of the contamination which has an unfavourable effect on physicochemical properties of soils and plants and namely also on human health. In the present work, water samples collected from Oued El-Harrach Algiers River, have been filtered in 0.45 ?m Millipore filters to be analysed by Energy Dispersive X-Ray Fluorescence technique using 109Cd radioisotope source. Concentrations of the toxic elements like heavy metals are determined and compared with the published ones values by Yoshida [1] and those obtained using PIXE and NAA techniques [6].

Ouziane, S.; Amokrane, A.; Toumert, I.

2013-12-01

321

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

NASA Astrophysics Data System (ADS)

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

Banerjee, Amit; Banerjee, S. S.

2014-05-01

322

Pre-concentration of rare earths using silica gel loaded with 1-(2-pyridylazo)-2-naphthol (PAN) and determination by energy dispersive X-ray fluorescence.  

PubMed

The determination of a single rare earth element in a mixture with other species of this family is a very challenging problem in analytical chemistry due to the close similarity of their chemical properties. In this work, a liquid-solid extraction procedure for praseodymium, neodymium, samarium and yttrium mixtures and subsequent determination by energy dispersive X-ray fluorescence spectrometry is described. The pre-concentration procedure, which involves the use of silica modified with 1-(2-pyridylazo)-2-naphthol, permits complete recovery of the rare earths and significant sensitivity enhancement in comparison with direct determination in the aqueous phase. Determinations in quaternary mixtures show typical precisions and accuracies of 3% and 5%, respectively. PMID:18967266

Cornejo-Ponce, L; Peralta-Zamora, P; Bueno, M I

1998-08-01

323

Determination of the geometric blurring of an energy dispersive X-ray diffraction (EDXRD) system and its use in the simulation of experimentally derived diffraction profiles  

NASA Astrophysics Data System (ADS)

A computational model has been developed to calculate the geometric blurring distribution of an energy dispersive X-ray diffraction (EDXRD) system. The scattering volume, trapezoid in the horizontal plane, is divided into typically of the order 10 4 elements and the blurring contribution of each element considered in an iterative procedure to build up a distribution for the entire trapezoid. The resultant distribution is asymmetric and peaks at angle below that nominally set. A correction for the focal spot intensity distribution has been included. The blurring distribution has been used as a filter to the Joint Committee on Powder Diffraction Standards (JCPDS) data for several materials to predict the experimentally derived diffraction profiles. A good agreement has been demonstrated between the simulated and measured spectra with a significant improvement on previous models assuming a Gaussian blurring distribution. The model can be used to predict the spectral blurring for any EDXRD system irrespective of the application.

Luggar, R. D.; Horrocks, J. A.; Speller, R. D.; Lacey, R. J.

1996-02-01

324

Iron Bacteria in Drinking-Water Distribution Systems: Elemental Analysis of Gallionella Stalks, Using X-Ray Energy-Dispersive Microanalysis  

PubMed Central

“Iron” bacteria belonging to the genus Gallionella were observed by scanning electron microscopy in water samples and attached to pipe surfaces in a Southern California drinking-water distribution system. The cells were recognized by their characteristic elongated helical stalks composed of numerous intertwined microfibrils. Many of the stalks were partially coated with insoluble ferric salt deposits. Stalks recovered directly from water samples were analyzed for their elemental composition by using X-ray energy-dispersive microanalysis. Silicon, aluminum, calcium, and iron were the predominant elements present in the stalks. Smaller quantities of the elements phosphorous, sulfur, chlorine, copper, and zinc were also detected. Manganese, though present in measurable quantities in the water supply, was not detected in the stalks, suggesting that this organism is unable to utilize this element as an electron donor. This represents the first such analysis of Gallionella stalks recovered from environmental samples without prior subculturing in artificial laboratory media. Images

Ridgway, H. F.; Means, E. G.; Olson, B. H.

1981-01-01

325

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

326

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

327

X-Ray Imaging  

Cancer.gov

X-ray imaging is perhaps the most familiar type of imaging. Images produced by X-rays are due to the different absorption rates of different tissues. Calcium in bones absorbs X-rays the most, so bones look white on a film recording of the X-ray image,

328

X-Ray Optics  

NASA Astrophysics Data System (ADS)

Due to the weak interaction of hard x-rays with matter it is generally difficult to manipulate x-rays by optical components. As a result, there have been many complementary approaches to making x-ray optics, exploiting refraction, reflection, and diffraction of x-rays by matter. In this chapter, we describe the physics that underly x-ray optics and explain the working principles and performances of a variety of x-ray optics, including refractive x-ray lenses, reflective optics, such as mirrors and waveguides, and diffractive optics,such as multilayer and crystal optics and Fresnel zone plates.

Schroer, Christian G.; Lengeler, Bruno

329

Femtosecond x-ray absorption spectroscopy with hard x-ray free electron laser  

SciTech Connect

We have developed a method of dispersive x-ray absorption spectroscopy with a hard x-ray free electron laser (XFEL), generated by a self-amplified spontaneous emission (SASE) mechanism. A transmission grating was utilized for splitting SASE-XFEL light, which has a relatively large bandwidth (?E/E ? 5 × 10{sup ?3}), into several branches. Two primary split beams were introduced into a dispersive spectrometer for measuring signal and reference spectra simultaneously. After normalization, we obtained a Zn K-edge absorption spectrum with a photon-energy range of 210 eV, which is in excellent agreement with that measured by a conventional wavelength-scanning method. From the analysis of the difference spectra, the noise ratio was evaluated to be ?3 × 10{sup ?3}, which is sufficiently small to trace minute changes in transient spectra induced by an ultrafast optical laser. This scheme enables us to perform single-shot, high-accuracy x-ray absorption spectroscopy with femtosecond time resolution.

Katayama, Tetsuo; Togashi, Tadashi; Tono, Kensuke; Kameshima, Takashi [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)] [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Inubushi, Yuichi; Sato, Takahiro; Hatsui, Takaki; Yabashi, Makina [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)] [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Obara, Yuki; Misawa, Kazuhiko [Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan)] [Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Bhattacharya, Atanu; Kurahashi, Naoya [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan)] [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Ogi, Yoshihiro [Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198 (Japan)] [Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198 (Japan); Suzuki, Toshinori [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan) [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako 351-0198 (Japan)

2013-09-23

330

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

331

Characterization of individual submicrometer aerosol particles collected in Incheon, Korea, by quantitative transmission electron microscopy energy-dispersive X-ray spectrometry  

NASA Astrophysics Data System (ADS)

For the last decade the Monte Carlo calculation method has been proven to be an excellent tool for accurately simulating electron-solid interactions in atmospheric individual particles of micrometer size. Although it was designed for application to scanning electron microscopy, in the present study it is demonstrated that the Monte Carlo calculation can also be applied in a quantitative single particle analysis using transmission electron microscopy (TEM) with an ultrathin window energy-dispersive X-ray (EDX) spectrometer with a high accelerating voltage (200 kV). By utilizing an iterative reverse Monte Carlo simulation combined with successive approximation, atomic elemental concentrations (including low-Z elements) of submicrometer standard particles were determined with high accuracy for electron beam refractory particles such as NaCl, KCl, SiO2, Fe2O3, Na2SO4, K2SO4, CaCO3, and CaSO4. On the basis of quantitative X-ray analysis together with morphological information from TEM images, overall 1638 submicrometer individual particles from 10 sets of aerosol samples collected in Incheon, Korea, were identified. The most frequently encountered particle types are carbonaceous and (NH4)2SO4/NH4HSO4-containing particles, followed by mineral (e.g., aluminosilicate, SiO2, CaCO3), sea salt, K-rich (e.g., K2SO4 and KCl), Fe-rich, fly ash, and transition or heavy-metal-containing (e.g., ZnSO4, ZnCl2, PbSO4) particles. The relative abundances of the submicrometer particle types vary among samples collected in different seasons and also depend on different air mass transport routes. This study demonstrates that the quantitative TEM-EDX individual particle analysis is a useful and reliable technique in characterizing urban submicrometer aerosol particles.

Geng, Hong; Kang, Sujin; Jung, Hae-Jin; ChoëL, Marie; Kim, Hyekyeong; Ro, Chul-Un

2010-08-01

332

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

333

APPLICATION OF SYNCHROTRON RADIATION TO HIGH PRESSURE X~RAY DIFFRACTION  

Microsoft Academic Search

The availability of dedicated, high brightness synchrotron radia­ tion sources is leading to many improvements in x-ray diffraction techniques. In addition to the widely discussed polychromatic energy dispersive tech­ niques, significant advances can be made by the use of monochromatic radiation in either angle- or wavelength-scanning. The application of these techniques, being developed at Daresbury, for high pressure investigations is

F. D. Hatton

334

Determining analyte concentrations in plutonium metal by x-ray fluorescence using a dried residue method  

Microsoft Academic Search

Accurately determining the concentration of certain elements in plutonium is of vital importance in manufacturing nuclear weapons. X-ray fluorescence (XRF) provides a means of obtaining this type of elemental information accurately, quickly, with high precision, and often with little sample preparation. In the present work, a novel method was developed to analyze the gallium concentration in plutonium samples using wavelength-dispersive

Christopher G. Worley; George J. Havrilla

2000-01-01

335

Analysis of fertilizer raw materials, intermediates, and products by x-ray fluorescence spectrometry  

Microsoft Academic Search

In 1976, a minerals beneficiation laboratory was established and investigations begun to explore beneficiating phosphatic raw materials. These laboratory efforts required an economical analytical service which provided rapid turnaround for large numbers of samples. X-ray fluorescence (XRF) spectrometry was selected as the technique most suited to both analytical and research requirements. In 1979 an XRF facility with an automated wavelength-dispersive

W. D. Wilhide; D. H. Ash

1985-01-01

336

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...

337

Analysis of particles produced during airbag deployment by scanning electron microscopy with energy dispersive x-ray spectroscopy and their deposition on surrounding surfaces: a mid-research summary  

Microsoft Academic Search

Airbags can be encountered in forensic work when investigating a car crash and are typically constructed with primerlike material to begin the deployment apparatus. The mechanisms of airbag deployment can produce particles ideal for scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM\\/EDS) analysis. A recent study published by Berk studied airbags with vents and showed that it is possible

J. Matney Wyatt

2011-01-01

338

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

339

X-ray laser interferometry: A new tool for AGEX  

Microsoft Academic Search

Collisionally pumped soft x-ray lasers now operate over a wavelength range extending from 4--40 nm. With the recent advances in the development of multilayer mirrors and beamsplitters in the soft x-ray regime, we can utilize the unique properties of x-ray lasers to study large, rapidly evolving laser-driven plasmas with high electron densities. By employing a shorter wavelength x-ray laser, as

A. S. Wan; J. C. Moreno; S. B. Libby

1995-01-01

340

Comparison of experimental and theoretical X-ray intensities from (In)GaAs specimens investigated by energy-dispersive X-ray spectroscopy in a transmission electron microscope  

NASA Astrophysics Data System (ADS)

Experimental measurements of X-ray line intensity ratios in a transmission electron microscope are compared over several orders of magnitude of sample thicknesses, from the nm- to the mm- range, with Monte-Carlo simulations using two different software packages. It is shown that the form of the thickness dependence of the K/L ratio of characteristic X-ray lines for GaAs is reproduced qualitatively, but the numerical differences between software packages are large. A scheme is presented for improving the simple k-factor method, taking explicitly into account the thickness dependence that remains even after application of the usual absorption and fluorescence corrections. This is done in first-order approximation by linear regression. The improvement in determining the correct indium concentration in specimens of InGaAs is calculated to be 1at%.

Walther, T.

2010-02-01

341

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

NASA Astrophysics Data System (ADS)

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

Green, Michael C.; Partain, Larry D.

2003-07-01

342

Measured conversion efficiencies of P45, paraterphenyl, tetraphenyl butadiene, and sodium salicylate phosphors in the soft-x-ray wavelength range  

SciTech Connect

The measured conversion efficiencies at 9.89, 23.6, 44.7, and 160 A of P45 phosphor screens, as well as those of paraterphenyl, tetraphenyl butadiene, and sodium salicylate at 9.89, 44.7, and 67.6 A, are presented. The conversion efficiency is defined as the ratio of photoelectrons ejected from the photocathode of a visible detector, which are excited by the scintillated photons that are emitted from the phosphor in a solid angle of 2[pi], to the number of soft-x-ray photons incident on the phosphor. The effect of the phosphor's thickness on the conversion efficiency was studied. The P45 phosphor converts the soft-x-ray photon (10--200 A) into an order of magnitude more visible photons than the low-[ital Z] phosphors. The P45 phosphor screen used in conjunction with a photomultiplier tube offers a soft-x-ray photodetector with a conversion efficiency that ranges from 0.5 at 160 A to 12 at 9.89 A and a high electronic gain.

Regan, S.P.; Huang, L.K.; May, M.J.; Moos, H.W. (Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)); Stutman, D.; Kovnovich, S.; Finkenthal, M. (Racah Institute of Physics, The Hebrew University, Jerusalem (Israel))

1994-06-01

343

New XRMF spectrometer with high resolution and high efficiency using polycapillary x-ray lens and PSPC+  

Microsoft Academic Search

A new spectrometer based on plane crystal wavelength dispersive method using a position sensitive proportional counter (PSPC) in conjunction with x-ray microbeam formed by monolithic polycapillary x-ray focusing lens has been developed. The new spectrometer could be used for XRMF analysis with high sensitivity, high spatial resolution and energy resolution simultaneously. The minimum spot sizes of the Cu-K(alpha) focused by

Xunliang Ding; Yiming Yan; Qiuli Pan; Yumei Yan; Yejun He

2001-01-01

344

The Need for X-Ray Spectroscopy  

NASA Technical Reports Server (NTRS)

For over four decades, X-ray, EUV, and UV spectral observations have been used to measure physical properties of the solar atmosphere. During this time, there has been substantial improvement in the spectral, spatial, and temporal resolution of the observations for the EUV and UV wavelength ranges. At wavelengths below 100 Angstroms, however, observations of the solar corona with simultaneous spatial and spectral resolution are limited, and not since the late 1970's have spatially resolved solar X-ray spectra been measured. The soft-X-ray wavelength range is dominated by emission lines formed at high temperatures and provides diagnostics unavailable in any other wavelength range. In this presentation, we will discuss the important science questions that can be answered using spatially and spectrally resolved X-ray spectra.

Winebarger, Amy R.; Cirtain, Jonathan; Kobayashi, Ken

2011-01-01

345

X-Ray Lasers  

ERIC Educational Resources Information Center

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

Chapline, George; Wood, Lowell

1975-01-01

346

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 ...

347

Sinus x-ray  

MedlinePLUS

Paranasal sinus radiography; X-ray - sinuses ... sinus x-ray is taken in a hospital radiology department. Or the x-ray may be taken ... Anslow P. Ear, nose and throat radiology. In: Adam A, Dixon AK, ... Radiology: A Textbook of Medical Imaging . 5th ed. Philadelphia, ...

348

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 ... The x-ray is used to detect fractures , tumors, or degenerative conditions of bones in the hips, pelvis, and ...

349

A rapid, dispersion-based wavelength-stepped and wavelength-swept laser for optical coherence tomography.  

PubMed

Optical-domain subsampling enables Fourier-domain OCT imaging at high-speeds and extended depth ranges while limiting the required acquisition bandwidth. To perform optical-domain subsampling, a wavelength-stepped rather than a wavelength-swept source is required. This preliminary study introduces a novel design for a rapid wavelength-stepped laser source that uses dispersive fibers in combination with a fast lithium-niobate modulator to achieve wavelength selection. A laser with 200 GHz wavelength-stepping and a sweep rate of 9 MHz over a 94 nm range at a center wavelength of 1550 nm is demonstrated. A reconfiguration of this source design to a continuous wavelength-swept light for conventional Fourier-domain OCT is also demonstrated. PMID:24663631

Tozburun, Serhat; Siddiqui, Meena; Vakoc, Benjamin J

2014-02-10

350

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

351

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

352

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

353

High pressure induced phase transition in sulfur doped indium phosphide: An angular-dispersive X-ray diffraction and Raman study  

NASA Astrophysics Data System (ADS)

The high pressure induced phase transitions in sulfur doped indium phosphide (InP:S) at ambient temperature has been investigated using angular-dispersive X-ray diffraction (ADXRD) and Raman scattering under high pressure up to around 44.6 and 37.4 GPa, respectively. In situ ADXRD measurements found that the transition of InP:S to a rock-salt phase began at 10.4 GPa and completed at 13.3 GPa with a 15.7% volume decrease. Another transition to the orthorhombic structure with space group Cmcm (the Cmcm phase) was found to occur at 35.8 GPa with a 4.1% volume decrease. The fitting of volume compression data to the third-order Birch-Murnaghan equation of state yielded that the zero-pressure isothermal bulk moduli (B0) and the first-pressure derivatives (B0') were 74 GPa and 3.9 for the zinc-blende phase, respectively. The rock-salt to Cmcm phase transition pressure increases relative to that of undoped InP of 32 GPa, which may be attributable to the increase of the ionicity of InP:S by S doping favorable to the ionic rock salt structure. In situ Raman measurements have similar findings.

Lin, Chih-Ming; Sheu, Hwo-Shuenn; Tsai, Min-Hsiung; Wu, Bi-Ru; Jian, Sheng-Rui

2009-01-01

354

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

355

Energy-dispersive X-ray spectrometry combined with directly suspended droplet microextraction for determination of dissolved silicate in surface water via silicomolybdenum blue complex.  

PubMed

Energy-dispersive X-ray fluorescence spectrometry (EDXRF) is a well-established analytical technique successfully applied with good precision and accuracy to determination of many elements. However, in the case of elements of low atomic number, such as silicon, direct determination is hampered due to low fluorescence yield and relatively low energy easily absorbed by sample matrix. An indirect method for determining surface water silicate is thus proposed. The method is based on silicate determination via molybdenum present in silicomolybdenum blue complex. Determination follows directly suspended droplet microextraction. Optimum conditions for both microextraction and EDXRF measurement were studied. A good ratio of silicon to molybdenum (1-41) and a sensitive K? line of molybdenum make it possible to determine low concentrations of silicate. Under optimized conditions, good linearity, up to 3?gmL(-1) (r=0.9990), and good detection limit (6ngmL(-1)) were achieved. The total RSD for the EDXRF determination of silicate following DSDME was 6.7%. Taking into account all steps preceding the determination and the uncertainty of XRF measurements, the proposed method can be recognized as precise. The enrichment factor was 140. The developed method was used to determine dissolved silicate content in surface water samples. The accuracy and repeatability of the proposed procedure were checked by standard addition method and compared to the results obtained using ICP-OES technique. The recovery (92.2-96%) was satisfactory and indicates usefulness of the developed procedure. PMID:25059189

Pytlakowska, Katarzyna

2014-10-01

356

Morphological and chemical changes in dentin after using endodontic agents: Fourier transform Raman spectroscopy, energy-dispersive x-ray fluorescence spectrometry, and scanning electron microscopy study  

NASA Astrophysics Data System (ADS)

We examine the morphological and chemical changes in the pulp chamber dentin after using endodontic agents by scanning electron microscopy (SEM), Fourier transform Raman spectroscopy (FT-Raman), and micro energy-dispersive x-ray fluorescence spectrometry (?EDXRF). Thirty teeth were sectioned exposing the pulp chamber and divided by six groups (n=5): NT-no treatment; CHX-2% chlorhexidine; CHXE-2% chlorhexidine+17% EDTA E-17% EDTA; SH5-5.25% NaOCl; SH5E-5.25% NaOCl+17% EDTA. The inorganic and organic content was analyzed by FT-Raman. ?EDXRF examined calcium (Ca) and phosphorus (P) content as well as Ca/P ratio. Impressions of specimens were evaluated by SEM. Data were submitted to Kruskal-Wallis and Dunn tests (p<0.05). Differences were observed among groups for the 960 cm-1 peak. Ca and P content differences were significant (SH5>NT=SH5E>CHX>E>CHXE). CHXE and E presented the highest Ca/P ratio values compared to the other groups (p<0.05). The SEM images in the EDTA-treated groups had the highest number of open tubules. Erosion in the tubules was observed in CHX and SH5E groups. Endodontic agents change the inorganic and organic content of pulp chamber dentin. NaOCl used alone, or in association with EDTA, was the most effective agent considering chemical and morphological approaches.

Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Soares, Luís Eduardo Silva; Santo, Ana Maria do Espírito; Martin, Airton Abraha~o.; Puppin-Rontani, Regina Maria

2012-07-01

357

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

358

Multiple scattering in dispersions, for long wavelength thermoacoustic solutions  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

359

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

360

X-Ray Supernovae  

NASA Astrophysics Data System (ADS)

We present a review of X-ray observations of supernovae. By observing the (char 1260.1-100 keV) X-ray emission from young supernovae, physical key parameters such as the circumstellar matter density, mass-loss rate of the progenitor, and temperature of the outgoing and reverse shocks can be derived as a function of time. Despite intensive search over the last char 12625 years, only 15 supernovae have been detected in X-rays. We review the individual X-ray observations of these supernovae and discuss their implications for our understanding of the physical processes giving rise to the X-ray emission.

Immler, S.; Lewin, W. H. G.

361

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

362

X-ray studies of coeval star samples. III. X-ray emission in the Ursa Major stream  

SciTech Connect

Results are reported from a comprehensive survey of X-ray emission from stars known or suspected to be members of the UMa cluster and/or stream. Of the 42 UMa member stars surveyed, 18 were detected as X-ray sources, and spectral analysis was performed for 10 stars with sufficient X-ray counts. Consideration is given to relations between X-ray luminosity, color, and kinematics of the sample stars, and the X-ray spectra of the UMa stars are discussed in the context of the general problem of stellar X-ray temperatures. Also confirmed is the lack of X-ray-emitting A dwarfs among UMa members; among stars of later spectra type there is a rather large dispersion in X-ray luminosity. This dispersion cannot readily be explained by contamination with field star interlopers and appears rather to be a property of the UMa X-ray luminosity distribution function. 43 refs.

Schmitt, J.H.M.M.; Micela, G.; Sciortino, S.; Vaiana, G.S.; Harnden, F.R., Jr. (Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany, F.R.) Osservatorio Astronomico, Palermo (Italy) Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA))

1990-03-01

363

X-ray studies of coeval star samples. III - X-ray emission in the Ursa Major stream  

NASA Technical Reports Server (NTRS)

Results are reported from a comprehensive survey of X-ray emission from stars known or suspected to be members of the UMa cluster and/or stream. Of the 42 UMa member stars surveyed, 18 were detected as X-ray sources, and spectral analysis was performed for 10 stars with sufficient X-ray counts. Consideration is given to relations between X-ray luminosity, color, and kinematics of the sample stars, and the X-ray spectra of the UMa stars are discussed in the context of the general problem of stellar X-ray temperatures. Also confirmed is the lack of X-ray-emitting A dwarfs among UMa members; among stars of later spectra type there is a rather large dispersion in X-ray luminosity. This dispersion cannot readily be explained by contamination with field star interlopers and appears rather to be a property of the UMa X-ray luminosity distribution function.

Schmitt, J. H. M. M.; Micela, G.; Sciortino, S.; Vaiana, G. S.; Harnden, F. R., Jr.

1990-01-01

364

Measurement of wavelengths and lamb shifts for inner-shell transitions in Fe XVIII-XXIV. [from solar flare X-ray spectra  

NASA Technical Reports Server (NTRS)

The wavelengths of inner-shell 1s-2p transitions in the ions Fe XVIII-XXIV have been measured in solar flare spectra recorded by the Naval Research Laboratory crystal spectrometer (SOLFLEX) on the Air Force P78-1 spacecraft. The measurements are compared with previous measurements and with recently calculated wavelengths. It is found that the measured wavelengths are systematically larger than the wavelengths calculated using the Z-expansion method by up to 0.65 mA. For the more highly charged ions, these differences can be attributed to the QED contributions to the transition energies that are not included in the Z-expansion calculations.

Seely, J. F.; Feldman, U.; Safronova, U. I.

1986-01-01

365

Electron density distribution and Madelung potential in alpha-spodumene, LiAl(SiO3)2, from two-wavelength high-resolution X-ray diffraction data.  

PubMed

The electron density distribution in alpha-spodumene, LiAl(SiO(3))(2), was derived from high-resolution X-ray diffraction experiments. The results obtained from both Mo Kalpha- and Ag Kalpha-wavelength data sets are reported. The features of the Si-O and Al-O bonds are related to the geometrical parameters of the Si-O-Al and Si-O-Si bridges on the one hand and to the O.Li(+) interaction on the other. Kappa refinements against the two data sets yielded almost the same net charges for the Si (+1.8 e) and O (-1.0 e) atoms in spodumene. However, the Al net charge obtained from the Ag Kalpha data (+1.9 e) is larger than the net charge derived from the Mo Kalpha data (+1.5 e). This difference correlates with a more contracted Al valence shell revealed by the shorter X-ray wavelength (kappa = 1.4 for the Ag Kalpha data set). The derived net charges were used to calculate the Madelung potential at the spodumene atomic sites. The electrostatic energy for the chemical formula LiAl(SiO(3))(2) was -8.60 e(2) Å(-1) (-123.84 eV) from the net charges derived from the Ag Kalpha data and -6.97 e(2) Å(-1) (-100.37 eV) from the net charges derived from the Mo Kalpha data. PMID:10927368

Kuntzinger; Ghermani

1999-06-01

366

Periodic dispersion management in soliton wavelength-division multiplexing transmission with sliding filters  

SciTech Connect

We compare the performance of dispersion-managed fibers with that of dispersion-decreasing fibers and of fibers with uniform dispersion in filtered soliton wavelength-division multiplexing transmission. Alternating-sign dispersion management allows us to achieve values of collision-induced timing jitter that are comparable with what can be achieved by use of dispersion-decreasing fiber and are lower for some parameter values. {copyright} {ital 1997} {ital Optical Society of America}

Golovchenko, E.A.; Pilipetskii, A.N.; Menyuk, C.R. [Department of Computer Sciences and Electrical Engineering, University of Maryland Baltimore County, Baltimore, Maryland 21250 (United States)

1997-08-01

367

INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Hard x-ray radiation yield from a dense plasma as a function of the wavelength of the heating ultrashort laser pulse  

NASA Astrophysics Data System (ADS)

The effect of intensity, length, and wavelength of an ultrashort laser pulse on the formation of a hot electron component in a dense laser-produced plasma was first investigated in a single experiment. For a pulse length of 1 ps (or 200 fs, but with an energy contrast ratio of ~20), it was shown that the principal mechanism of generation of hot electrons is the resonance absorption of laser radiation and that the temperature of hot electrons depends on the laser pulse intensity I and the wavelength ? as Th~(I?2)1/3. The homogenisation of the nanostructures of porous silicon due to a poor contrast ratio or a long duration (1 ps) of the laser pulse lowers the yield of hard x-ray radiation compared to the case of high-contrast 200-fs pulses.

Varanavicius, A.; Vlasov, T. V.; Volkov, Roman V.; Gavrilov, S. A.; Gordienko, Vyacheslav M.; Dubetis, A.; Zeromskis, E.; Piskarskas, A.; Savel'ev, Andrei B.; Tamosauskas, G.

2000-06-01

368

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

NASA Astrophysics Data System (ADS)

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

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

1992-09-01

369

X-Rays for Children  

MedlinePLUS

... on the goal: Bitewing X-rays (also called cavity-detecting X-rays) — These X-rays are used ... that cannot be seen directly. They show where cavities are starting. These X-rays are needed only ...

370

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

371

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

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

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

PubMed

Calcium carbonate is the most abundant biomineral and a compound of great industrial importance. Its precipitation from solution has been studied extensively and was often shown to proceed via distinct intermediate phases, which undergo sequential transformations before eventually yielding the stable crystalline polymorph, calcite. In the present work, we have investigated the crystallisation of calcium carbonate in a time-resolved and non-invasive manner by means of energy-dispersive X-ray diffraction (EDXRD) using synchrotron radiation. In particular, the role of silica as a soluble additive during the crystallisation process was examined. Measurements were carried out at different temperatures (20, 50 and 80 °C) and various silica concentrations. Experiments conducted in the absence of silica reflect the continuous conversion of kinetically formed metastable polymorphs (vaterite and aragonite) to calcite and allow for quantifying the progress of transformation. Addition of silica induced remarkable changes in the temporal evolution of polymorphic fractions existing in the system. Essentially, the formation of calcite was found to be accelerated at 20 °C, whereas marked retardation or complete inhibition of phase transitions was observed at higher temperatures. These findings are explained in terms of a competition between the promotional effect of silica on calcite growth rates and kinetic stabilisation of vaterite and aragonite due to adsorption (or precipitation) of silica on their surfaces, along with temperature-dependent variations of silica condensation rates. Data collected at high silica concentrations indicate the presence of an amorphous phase over extended frames of time, suggesting that initially generated ACC particles are progressively stabilised by silica. Our results may have important implications for CaCO3 precipitation scenarios in both geochemical and industrial settings, where solution silicate is omnipresent, as well as for CO2 sequestration technologies. PMID:23807473

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

2013-08-01

374

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

375

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

2012-08-30

376

Adsorption of N/S heterocycles in the flexible metal-organic framework MIL-53(Fe(III)) studied by in situ energy dispersive X-ray diffraction.  

PubMed

The adsorption of N/S-containing heterocyclic organic molecules in the flexible iron(III) terephthalate MIL-53, Fe(III)(OH)(0.6)F(0.4)(O2C-C6H4-CO2)·(H2O), from the liquid phase was studied with in situ energy dispersive X-ray diffraction (EDXRD), in order to follow the adsorption-induced expansion of the structure. For comparison with the diffraction data, liquid phase adsorption isotherms were recorded for uptake of benzothiophene, benzothiazole and indole in isopropanol and in heptane. The solvent not only influences pore opening but is also a competing guest. The in situ EDXRD experiments allow the kinetics of guest uptake and the competition with solvent to be monitored directly. Indole uptake is limited; this adsorbate is barely capable of opening the closed, either hydrated or dehydrated, MIL-53(Fe) structure, or of penetrating the isopropanol-containing material in the concentration range under study. When isopropanol is used as a solvent, the guest molecules benzothiophene and benzothiazole must be present at a certain threshold concentration before substantial adsorption into the metal-organic framework takes place, eventually resulting in full opening of the structure. The fully expanded structures of benzothiophene or benzothiazole loaded MIL-53(Fe) materials have Imcm symmetry and a unit cell volume of ca. 1600 Å(3), and upon uptake of the guest molecules by the closed form (unit cell volume ~1000 Å(3)) no intermediate crystalline phases are seen. Successful uptake by MIL-53(Fe) requires that the adsorbate is primarily a good hydrogen bond acceptor; additionally, based on UV-visible spectroscopy, a charge-transfer interaction between the S atoms of benzothiophene and the aromatic rings in the MOF pore wall is proposed. PMID:23439974

Van de Voorde, Ben; Munn, Alexis S; Guillou, Nathalie; Millange, Franck; De Vos, Dirk E; Walton, Richard I

2013-06-14

377

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

378

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

2011-10-31

379

X-ray binaries  

NASA Technical Reports Server (NTRS)

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

1976-01-01

380

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

381

The identification of the pigments used to paint statues of Feixiange Cliff in China in late 19th century by micro-Raman spectroscopy and scanning electron microscopy\\/energy dispersive X-ray analysis  

Microsoft Academic Search

The application of micro-Raman spectroscopy (?-RS) and scanning electron microscopy (SEM)\\/energy dispersive X-ray spectrometer (EDS) to the research of pigments collected from Statues of Feixiange Cliff No. 67 and No. 69 niche of Tang Dynasty in China is reported. Five kinds of pigments were found in the experimental data, including black (carbon), white (gypsum+quartz), blue (lapis lazuli) and green (Paris

Pu-jun Jin; Wei Huang; Jianhua-Wang; Gang Zhao; Xiao-ling Wang

2010-01-01

382

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

383

Quantitative Energy-Dispersive X-Ray Microanalysis of Calcium Dynamics in Cell Suspensions during Stimulation on a Subsecond Time Scale: Preparative and Analytical Aspects as Exemplified with Paramecium Cells  

Microsoft Academic Search

We analyzed preparative and analytical aspects of the dynamic localization of Ca2+ during cell stimulation, using a combination of quenched flow and energy-dispersive X-ray microanalysis (EDX). Calcium (or Sr, as a substitute) was retained as fluorides during freeze-substitution, followed by epoxide embedding. The quenched-flow used allowed analyses, during stimulation, in the subsecond time range. Sections of 500 nm were analyzed

Martin Hardt; Helmut Plattner

1999-01-01

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  

NASA Astrophysics Data System (ADS)

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.; Nachtegaal, M.; de Boni, E.; Willimann, M.; Safonova, O.; Sa, J.; Smolentsev, G.; Szlachetko, M.; van Bokhoven, J. A.; Dousse, J.-Cl.; Hoszowska, J.; Kayser, Y.; Jagodzinski, P.; Bergamaschi, A.; Schmitt, B.; David, C.; Lücke, A.

2012-10-01

385

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

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

386

Quantitative Measurements of X-ray Intensity  

SciTech Connect

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

Haugh, M. J., Schneider, M.

2011-09-01

387

X-ray binaries  

Microsoft Academic Search

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

H. Schatz; K. E. Rehm

2006-01-01

388

The high energy X-ray universe  

PubMed Central

Since its beginning in the early 1960s, the field of X-ray astronomy has exploded, experiencing a ten-billion-fold increase in sensitivity, which brought it on par with the most advanced facilities at all wavelengths. I will briefly describe the revolutionary first discoveries prior to the launch of the Chandra and XMM-Newton X-ray observatories, present some of the current achievements, and offer some thoughts about the future of this field.

Giacconi, Riccardo

2010-01-01

389

Lacquer polishing of X-ray optics  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

390

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

Microsoft Academic Search

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

Pert

2007-01-01

391

Fundamental physics with an X-ray free electron laser  

Microsoft Academic Search

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

T. Tajima

2003-01-01

392

Widely Wavelength-Tunable Blue-Shifted Dispersive Waves for Broadband Visible Wavelength Generation in a Photonic Crystal Fiber Cladding  

NASA Astrophysics Data System (ADS)

Blue-shifted dispersive waves (DWs) are efficiently generated from the red-shifted solitons by coupling the 120 fs pulses into the fundamental mode of the multi-knots of a photonic crystal fiber cladding. When the femtosecond pulses at the wavelength of 825 nm and the average power of 300 mW are coupled into knots 1-3, the conversion efficiency ?DW of 32% and bandwidth BDW of 50 nm are obtained. The ultrashort pulses generated by the DWs can be tunable over the whole visible wavelength by adjusting the wavelengths of the pump pulses coupled into different knots. It can be believed that this widely wavelength-tunable ultrashort visible pulse source has important applications in ultrafast photonics and resonant Raman scattering.

Yuan, Jin-Hui; Sang, Xin-Zhu; Yu, Chong-Xiu; Shen, Xiang-Wei; Wang, Kui-Ru; Yan, Bin-Bin; Han, Ying; Zhou, Gui-Yao; Hou, Lan-Tian

2012-10-01

393

Development of a soft x-ray diffractometer for a wideband multilayer grating with a novel layer structure in the 2-4 keV range  

SciTech Connect

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 [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215 (Japan); Device Dept., Shimadzu Corp., 1 Nishinokyo-Kuwabara-cho, Nakagyo-ku, Kyoto 604-8511 (Japan); IMRAM, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); ECBU, JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 (Japan)

2012-07-11

394

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

SciTech Connect

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

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

2007-06-15

395

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

396

X rays from quasimolecules  

NASA Astrophysics Data System (ADS)

In slow heavy-ion-atom collisions, inner-shell electrons with velocities larger than the projectile velocity form diatomic molecular orbitals around the projectile and target nuclei. If a vacancy exists in one of these orbitals, it can decay at some point during collision, emitting an x ray characteristic of the molecular transition energy at that internuclear distance. Since the projectile-target internuclear distance varies during the collision, x-ray continua are seen, which for 1s? molecular-orbital x rays (transitions to vacancies in the lowest 1s? orbital) stretch toward the united-atom K-shell binding energy. This paper reviews the theory of and the experimental evidence for molecular-orbital x-ray emission. A historical overview of the development of these studies is given, showing how the theory of quasimolecular x-ray emission has evolved from a semiclassical quasistatic model to a general dynamic theory, including the Coriolis coupling between molecular orbitals making up the initial and final states. X-ray cross section, angular distribution, and other measurements are discussed, and their impact on the development of the theory of molecular-orbital x-ray emission is illustrated.

Anholt, R.

1985-10-01

397

X-ray crystallography  

NASA Technical Reports Server (NTRS)

X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

2001-01-01

398

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 ...

399

Lumbosacral spine x-ray  

MedlinePLUS

X-ray - lumbosacral spine; X-ray - lower spine ... The test is done in a hospital x-ray department or your health care provider's office by an x-ray technician. You will be asked to lie on the x-ray ...

400

X-ray laser  

DOEpatents

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

Nilsen, Joseph (Livermore, CA)

1991-01-01

401

Incomplete collisions of wavelength-division multiplexed dispersion-managed solitons  

Microsoft Academic Search

Interactions of wavelength-division multiplexed (WDM) dispersion-managed solitons solitons are studied by means of numerical simulations of both the nonlinear Schrodinger (NLS) equation and the nonlocal equation of the NLS type that describes pulse dynamics in systems with strong dispersion management. The interac- tion properties are found to depend significantly on the values of system parameters. Incomplete collisions can be particularly

Mark J. Ablowitz; Gino Biondini; Eric S. Olson

2001-01-01

402

Interactions of dispersion-managed solitons in wavelength-division-multiplexed optical transmission lines.  

PubMed

We investigate interactions between pulses in dispersion-managed multichannel wavelength-division-multiplexed soliton systems, using an improved variational approximation. The frequency shifts are found to be smallest for moderate, i.e., relatively short-scale, dispersion management. The position shifts increase monotonically with map strength. PMID:18040502

Wald, M; Malomed, B A; Lederer, F

2001-07-01

403

From zone plate to microcalorimeter . 50 years of cosmic X-ray spectroscopy at SRON  

NASA Astrophysics Data System (ADS)

The first method used by the SRON Laboratory for Space Research at Utrecht to spectroscopically image the Sun in X-rays employed Fresnel zone plates. Four Fresnel plates, covering four specific wavelengths, were flown on an Aerobee rocket in 1967 and gave a first useful X-ray image of the Sun in the Si-X line at 51 Å. The technique developed for the solar X-ray images enabled SRON to become the Lead Investigator for the grating spectrographs on several major X-ray satellites, i.e. on the Einstein and EXOSAT satellites, launched in November 1978 and May 1983 respectively, and on the Chandra and XMM-Newton observatories both launched in 1999. Since then, a considerable effort was put into the development of cryogenically cooled, non-dispersive X-ray spectrometers as model payload elements for the XEUS, IXO and Athena mission studies. This paper briefly reviews these developments, highlights some of the resulting scientific insights and offers a few thoughts on the present outlook for a next generation X-ray observatory. The biggest challenge for the realization of such a mission is not primarily technical: global coordination and collaboration, both among scientists and the major space agencies, is a prerequisite for a successful next major leap in this discipline.

Bleeker, J.; Verbunt, F.

404

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

405

X-Ray Diffraction.  

ERIC Educational Resources Information Center

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

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

1980-01-01

406

Medical X-Rays  

MedlinePLUS

... should be taken in reducing radiation exposure to pediatric patients for all types of X-ray imaging exams ( ... for use with special patient groups (i.e. pediatric patients) when making purchasing decisions. Assure appropriate credentials and ...

407

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

This final report covers the period 1 January 1985 - 31 March 1992. It is divided into the following sections: the soft x-ray background; proportional counter and filter calibrations; sounding rocket flight preparations; new sounding rocket payload: x-ray calorimeter; and theoretical studies. Staff, publications, conference proceedings, invited talks, contributed talks, colloquia and seminars, public service lectures, and Ph. D. theses are listed.

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

1992-01-01

408

Study of Phonon Dispersion in Silicon and Germanium at Long Wavelengths Using Picosecond Ultrasonics  

SciTech Connect

We have studied the dispersion of long wavelength longitudinal phonons in silicon and germanium using ultrasonic techniques. For long wavelengths, the acoustic phonon dispersion relation is of the form {omega}(k){approx_equal}ck-{gamma}k{sup 3} , where c is the speed of sound and {gamma} measures the lowest-order phonon dispersion. By sending an ultrasonic pulse of length a few hundred angstroms into a crystal and measuring the change of the pulse shape with propagation distance, we are able to determine the parameter {gamma} . The results are compared with lattice dynamics models. (c) 2000 The American Physical Society.

Hao, H.-Y.; Maris, H. J.

2000-06-12

409

Dynamic control of spatial wavelength dispersion in holographic femtosecond laser processing.  

PubMed

Dynamic control of spatial wavelength dispersion is effective due to a potentially large spectral bandwidth of femtosecond pulses, in particular, when using sub-100-fs pulses. We demonstrate spatial wavelength dispersion control, which drastically reduces focal spot distortion in the reconstruction of a hologram, using a pair of spatial light modulators. The improved diffraction spots had nearly diffraction-limited spot sizes, agreeing well with theoretical predictions. The dynamic control of dispersion is also demonstrated in order to restrain unnecessary processing given by the zeroth-order pulse. PMID:24487844

Hasegawa, Satoshi; Hayasaki, Yoshio

2014-02-01

410

X-ray converter  

US Patent & Trademark Office Database

An X-RAY CONVERTER having a light-proof housing with an X-ray-transparent wall behind which there are fastened an X-ray-to-optical converter, a filter of residual X-radiation, an objective lenses unit, and a photodetector containing at least two optoelectronic converters with partly overlapping fields of view and separated electrical outputs for connection to a system for processing of fragmentary video signals and generating an integral output video signal. For improving the efficiency of suppression of internal interferences in optical channels and the operating reliability, within the housing, parallel to the X-ray-to-optical converter, there is rigidly fastened an additional light- and X-ray-opaque partition with through-holes which in the number and placement correspond to objective lenses and optoelectronic converters and are blocked by washers of the filter of residual X-radiation, and ahead of the washers there are installed blinds, length A of each of which and distance D from the front surface of the X-ray-to-optical converter to the plane of front end faces of objective lenses are related by the ratio A/D=(0.50 . . . 0.95).

2009-02-24

411

X-Ray Background Survey Spectrometer (XBSS)  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

412

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

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

Characterization of toners and inkjets by laser ablation spectrochemical methods and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy  

NASA Astrophysics Data System (ADS)

Detection and sourcing of counterfeit currency, examination of counterfeit security documents and determination of authenticity of medical records are examples of common forensic document investigations. In these cases, the physical and chemical composition of the ink entries can provide important information for the assessment of the authenticity of the document or for making inferences about common source. Previous results reported by our group have demonstrated that elemental analysis, using either Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) or Laser Ablation Induced Breakdown Spectroscopy (LIBS), provides an effective, practical and robust technique for the discrimination of document substrates and writing inks with minimal damage to the document. In this study, laser-based methods and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) methods were developed, optimized and validated for the forensic analysis of more complex inks such as toners and inkjets, to determine if their elemental composition can differentiate documents printed from different sources and to associate documents that originated from the same printing source. Comparison of the performance of each of these methods is presented, including the analytical figures of merit, discrimination capability and error rates. Different calibration strategies resulting in semi-quantitative and qualitative analysis, comparison methods (match criteria) and data analysis and interpretation tools were also developed. A total of 27 black laser toners originating from different manufacturing sources and/or batches were examined to evaluate the discrimination capability of each method. The results suggest that SEM-EDS offers relatively poor discrimination capability for this set (~ 70.7% discrimination of all the possible comparison pairs or a 29.3% type II error rate). Nonetheless, SEM-EDS can still be used as a complementary method of analysis since it has the advantage of being non-destructive to the sample in addition to providing imaging capabilities to further characterize toner samples by their particle morphology. Laser sampling methods resulted in an improvement of the discrimination between different sources with LIBS producing 89% discrimination and LA-ICP-MS resulting in 100% discrimination. In addition, a set of 21 black inkjet samples was examined by each method. The results show that SEM-EDS is not appropriate for inkjet examinations since their elemental composition is typically below the detection capabilities with only sulfur detected in this set, providing only 47.4% discrimination between possible comparison pairs. Laser sampling methods were shown to provide discrimination greater than 94% for this same inkjet set with false exclusion and false inclusion rates lower than 4.1% and 5.7%, for LA-ICP-MS and LIBS respectively. Overall these results confirmed the utility of the examination of printed documents by laser-based micro-spectrochemical methods. SEM-EDS analysis of toners produced a limited utility for discrimination within sources but was not an effective tool for inkjet ink discrimination. Both LA-ICP-MS and LIBS can be used in forensic laboratories to chemically characterize inks on documents and to complement the information obtained by conventional methods and enhance their evidential value.

Trejos, Tatiana; Corzo, Ruthmara; Subedi, Kiran; Almirall, José

2014-02-01

415

Melting of tantalum at high pressure determined by angle dispersive x-ray diffraction in a double-sided laser-heated diamond-anvil cell  

Microsoft Academic Search

The high-pressure and high-temperature phase diagram of Ta has been studied in a laser-heated diamond-anvil cell (DAC) using x-ray diffraction measurements up to 52GPa and 3800K. The melting was observed at nine different pressures, the melting temperature being in good agreement with previous laser-heated DAC experiments, but in contradiction with several theoretical calculations and previous piston–cylinder apparatus experiments. A small

D Errandonea; M Somayazulu; H. K. Mao

2003-01-01

416

Melting of tantalum at high pressure determined by angle dispersive x-ray diffraction in a double-sided laser-heated diamond-anvil cell  

Microsoft Academic Search

The high-pressure and high-temperature phase diagram of Ta has been studied in a laser-heated diamond-anvil cell (DAC) using x-ray diffraction measurements up to 52 GPa and 3800 K. The melting was observed at nine different pressures, the melting temperature being in good agreement with previous laser-heated DAC experiments, but in contradiction with several theoretical calculations and previous piston-cylinder apparatus experiments.

D. Errandonea; M. Somayazulu; D. Häusermann; H. K. Mao

2003-01-01

417

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

418

X-ray sensitive charge-coupled device instrumentation for short and ultrashort pulse laser-produced plasma experiments  

SciTech Connect

We describe the use of x-ray sensitive charge-coupled device (CCD) detectors for measuring the 1--15 A emission from high temperature plasmas produced at the [ital L]-Division JANUS and USP (pulse length[similar to]100 fs) laser facilities. Instruments based upon commercially available video format cameras have been designed to replace x-ray film, as the two-dimensional recording medium, for imaging and x-ray spectroscopic applications. Used in conjunction with a high sensitivity x-ray pinhole camera, magnification 5--20, the CCD detectors can give spatial resolution approaching 5 [mu]m and energy band information by the use of edge filters. A compact wavelength dispersive spectrometer equipped with the CCD detector and a flat Bragg crystal analyzer can record survey spectra.

Dunn, J.; Young, B.K.F.; Shiromizu, S.J. (L-Division, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States))

1995-01-01

419

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

420

Determining analyte concentrations in plutonium metal by x-ray fluorescence using a dried residue method  

NASA Astrophysics Data System (ADS)

Accurately determining the concentration of certain elements in plutonium is of vital importance in manufacturing nuclear weapons. X-ray fluorescence (XRF) provides a means of obtaining this type of elemental information accurately, quickly, with high precision, and often with little sample preparation. In the present work, a novel method was developed to analyze the gallium concentration in plutonium samples using wavelength-dispersive XRF. A description of the analytical method will be discussed. .

Worley, Christopher G.; Havrilla, George J.

2000-07-01

421

Electron and proton induced x-ray spectrometry: Two complementary spatially resolved analytical techniques in mineralogy  

Microsoft Academic Search

Spatially resolved quantitative analysis by means of the electron probe micro analyzer (EPMA) is now well-established as a routine analytical method for point chemical analysis of a variety of mineral materials. Modern computer controlled EPMA are most often equipped with wavelength dispersive spectrometers (WDS). Quantitative analysis are generally carried out according to a standard based approached, i.e. the x-ray intensities

G. Remond; C. Gilles; D. Isabelle; C. Choi; M. Azahra; O. Rouer; F. Cesbron

1995-01-01

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

5.8 X-ray Calorimeters  

NASA Technical Reports Server (NTRS)

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-the-art calorimeter instruments have resolving powers of over 3000, large simultaneous band-passes, 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. In this chapter I briefly review the detection scheme, the state-of-the-art in X-ray calorimeter instruments and the future outlook for this technology.

Porter, F. Scott

2008-01-01

424

Chemical effects in the K? X-ray emission spectra of sulfur  

NASA Astrophysics Data System (ADS)

In this work our previous study about chemical effects in the K? spectra of S compounds employing high-resolution X-ray spectroscopy has been extended to the K? emission spectra. The measurements were performed with a wavelength dispersive single crystal spectrometer operated in the von Hamos geometry having an energy resolution comparable to the natural linewidth of the measured K? X-ray lines. The target fluorescence was produced by irradiating the samples with the bremsstrahlung from an X-ray tube. The energies and widths of the main components in the K? emission spectrum are given for different sulfur compounds (sulfide, sulfite, sulfate). The measured energy shifts between the K? lines of the compounds and elemental sulfur are presented as a function of the sulfur oxidation state and compared with the results obtained from the former K? measurements.

Kav?i?, M.; Dousse, J.-Cl.; Szlachetko, J.; Cao, W.

2007-07-01

425

High-throughput x-ray characterization system for combinatorial materials studies  

NASA Astrophysics Data System (ADS)

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 control the measurement system and data acquisition automatically. Examples are also demonstrated to show the applicability of this system.

Luo, Zhenlin; Geng, Bin; Bao, Jun; Liu, Cihui; Liu, Wenhan; Gao, Chen; Liu, Zhiguo; Ding, Xunliang

2005-09-01

426

High-throughput x-ray characterization system for combinatorial materials studies  

SciTech Connect

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 control the measurement system and data acquisition automatically. Examples are also demonstrated to show the applicability of this system.

Luo Zhenlin; Geng Bin; Bao Jun; Liu Cihui; Liu Wenhan; Gao Chen; Liu Zhiguo; Ding Xunliang [National Synchrotron Radiation Laboratory and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230029 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China)

2005-09-15

427

In-situ synchrotron energy-dispersive x-ray diffraction study of thin Pd foils with Pd:D and Pd:H concentrations up to 1:1  

NASA Astrophysics Data System (ADS)

Time resolved, in-situ, energy dispersive x-ray diffraction was performed in an electrolysis cell during electrochemical loading of palladium foil cathodes with hydrogen and deuterium. Concentrations of H:Pd (D:Pd) up to 1:1 in 0.1 M LiOH (LiOD) in H2O (D2O) electrolyte were obtained, as determined by both the Pd lattice parameter and cathode resistivity. In addition, some indications on the kinetics of loading and deloading of hydrogen from the Pd surface were obtained. The alpha-beta phase transformations were clearly delineated but no new phases at high concentration were determined.

Knies, D. L.; Violante, V.; Grabowski, K. S.; Hu, J. Z.; Dominguez, D. D.; He, J. H.; Qadri, S. B.; Hubler, G. K.

2012-10-01

428

Modified Raman Response Model and Supercontinuum Generation in Flat Dispersion Photonic Crystal Fiber with Two-Zero Dispersion Wavelengths  

NASA Astrophysics Data System (ADS)

The generation mechanisms of supercontinuum (SC) and the effect of the modified Raman model on SC are further analyzed in a flat dispersion photonic crystal fiber (PCF) with two-zero dispersion wavelengths (TZDWs) by introducing an accurate Raman response function in the scalar nonlinear Schrödinger equation. The results show that the introduction of Boson peak in the modified Raman gain model not only results in much rapider broadening of SC but also promotes more pump pulse energy transferred to the short wavelength region, which is related to stimulated Raman scattering. Moreover, SC generated from the PCF splits into two spectral bands, and their spectral peaks rapidly separate and broaden with the increase of incident power. Double-band central wavelengths are finally located at about 850 nm and 1220 nm. The pumping energy depletion phenomenon occurs. The simulated results from the modified Raman model are in better agreement with the experimental results than that from the single-Lorentzian model.

Wang, He-Lin; Yang, Ai-Jun; Leng, Yu-Xin; Wang, Cheng

2011-03-01

429

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

430

A Test for the Anisotropy of X-ray Emission from Ultraluminous X-ray Sources  

NASA Astrophysics Data System (ADS)

If the emission from ultraluminous X-ray sources (ULX) is anisotropic, the luminosities can be less than the Eddington Luminosity for a 15 Msun black hole (2x1039 erg/s), obviating the need for intermediate mass black holes. We can test the isotropy condition because a fraction of the X-ray emission is absorbed by cold material, and much of this absorbed power will be reemitted isotropically by dust grains at infrared wavelengths. The ratio of the infrared luminosity to the absorbed X-ray luminosity is a measure of the anisotropy of the X-ray emission. We failed to detect infrared emission from the ULX in NGC 1313 using observations obtained with the IRAC and MIPS instruments on the Spitzer Observatory. The upper limit to the infrared power is well below the value expected if the X-ray emission is isotropic. If our model for the conversion of absorbed X-ray photons to dust reemission is correct, the inferred opening angle of the X-ray emission is less than 30 degrees, implying that the intrinsic X-ray luminosity is less than 2x1039 erg/s.

Bregman, Joel Norman; Miller, J. M.; Irwin, J. A.

2007-12-01

431

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

432

X-ray fluorescence experiment  

NASA Technical Reports Server (NTRS)

The preliminary results from the Sco X-1 and Cyg X-1 obtained from the Apollo 15 X-ray detector data are presented along with preliminary results of the X-ray fluorescence spectrometric data of the lunar surface composition. The production of the characteristic X-rays following the interaction of solar X-rays with the lunar surface is described along with the X-ray spectrometer. Preliminary analyses of the astronomical X-ray observation and the X-ray fluorescence data are presented.

Adler, I.; Trombka, J. I.; Gerard, J.; Schmadebeck, R.; Lowman, P.; Blodgett, H.; Yin, L.; Eller, E.; Lamothe, R.; Gorenstein, P.

1972-01-01

433

Hybrid X-ray telescope systems  

NASA Astrophysics Data System (ADS)

It has been known for some time that glancing incidence X-ray optics have sharply peaked point response functions. The spatial resolution of Wolter X-ray telescope systems is frequently limited by the performance characteristics of the X-ray detector rather than by the optics, even when high resolution detectors such as photographic emulsions are used. This problem becomes even more severe when it is desirable to take advantage of the high sensitivity and broad wavelength response afforded by modern solid state detectors such as charge coupled devices or multi-anode microchannel arrays. Results of theoretical investigations of methods for increasing the telescope plate scale by the use of glancing incidence hyperboloid/ellipsoid X-ray microscope optics and normal incidence contoured layered synthetic microstructure optics for coupling the Wolter mirrors to the detector are reported. The relative merits of the different hybrid X-ray telescope systems which result will be discussed. Considerations will be made concerning applications of these systems to high resolution imagery and spectroscopy of astronomical X-ray/XUV sources.

Shealy, David L.; Hoover, Richard B.

1986-01-01

434

Compton backscattered collimated x-ray source  

DOEpatents

A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

Ruth, R.D.; Huang, Z.

1998-10-20

435

Compton backscattered collimated x-ray source  

DOEpatents

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

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

1998-01-01

436