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1

Wavelength Dispersive X-ray Absorption Fine Structure Imaging by Parametric X-ray Radiation  

NASA Astrophysics Data System (ADS)

The parametric X-ray radiation (PXR) generator system at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University is a monochromatic and coherent X-ray source with horizontal wavelength dispersion. The energy definition of the X-rays, which depends on the horizontal size of the incident electron beam on the generator target crystal, has been investigated experimentally by measuring the X-ray absorption near edge structure (XANES) spectra on Cu and CuO associated with conventional X-ray absorption imaging technique. The result demonstrated the controllability of the spectrum resolution of XANES by adjusting of the horizontal electron beam size on the target crystal. The XANES spectra were obtained with energy resolution of several eV at the narrowest case, which is in qualitative agreement with the energy definition of the PXR X-rays evaluated from geometrical consideration. The result also suggested that the wavelength dispersive X-ray absorption fine structure measurement associated with imaging technique is one of the promising applications of PXR.

Inagaki, Manabu; Hayakawa, Yasushi; Nogami, Kyoko; Tanaka, Toshinari; Hayakawa, Ken; Sakai, Takeshi; Nakao, Keisuke; Sato, Isamu

2008-10-01

2

A multi-crystal wavelength dispersive x-ray spectrometer  

SciTech Connect

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

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

2012-07-15

3

12.141 Electron Microprobe Analysis by Wavelength Dispersive X-ray Spectrometry, January (IAP) 2006  

E-print Network

Introduction to the theory of x-ray microanalysis through the electron microprobe including ZAF matrix corrections. Techniques to be discussed are wavelength and energy dispersive spectrometry, scanning backscattered ...

Chatterjee, Nilanjan

4

Calibration of wavelength-dispersive X-ray spectrometer for standardless analysis  

NASA Astrophysics Data System (ADS)

An experimental procedure for calibrating wavelength-dispersive X-ray spectrometer is presented. The detection efficiency was determined from the ratio of fluorescent radiation measured using the flow-proportional and the scintillation counter. The relative reflection efficiency of the analyzing crystal for various wavelengths was determined from the X-ray measurements of standard samples. The absorption correction for the atmosphere in the spectrometer chamber was also experimentally examined. All parameters (with the exception of reflection efficiency of the analyzing crystal) can be calculated from the X-ray measurements of unknown samples.

Sitko, Rafa?; Zawisza, Beata

2005-01-01

5

Measuring surface and grain boundary segregation using wavelength dispersive X-ray spectroscopy  

Microsoft Academic Search

Electron probe microanalysis (EPMA) using wavelength dispersive X-ray spectroscopy (EPMA-WDS) is applied to the quantification of surface and grain boundary monolayer segregation. The case of sulphur segregation in nickel and nickel alloys is considered. It is evidenced that EPMA-WDS is able to detect submonolayer surface segregation. The sulphur segregation can be accurately quantified from the sulphur K? line relative intensity

F. Christien; R. Le Gall

2008-01-01

6

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

7

Wavelength dispersing devices for soft and ultrasoft x-ray spectrometers  

SciTech Connect

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

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

1984-01-01

8

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...

9

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

10

Investigation of certain crystal growth characteristics in melt-textured YBCO superconductor using wavelength dispersive X-ray analysis  

Microsoft Academic Search

Using wavelength dispersive X-ray analysis, it is found that some non-superconducting Y2BaCuO5 (Y-211) grains in the melt-textured YBCO superconductor demonstrate uneven distribution of Y atoms. Such a phenomenon can be explained by diffusion of Y atoms between the YBa2Cu3Oy (Y-123)\\/liquid interface, the Y-211\\/liquid interface and the Y-211 grain inside. Moreover, ‘gaps’-generated due to different degrees of contractions of the matrix

J. C. L Chow; P. C. W Fung; Y. H Zhang

1995-01-01

11

Investigation of certain crystal growth characteristics in melt-textured YBCO superconductor using wavelength dispersive X-ray analysis  

NASA Astrophysics Data System (ADS)

Using wavelength dispersive X-ray analysis, it is found that some non-superconducting Y 2BaCuO 5 (Y-211) grains in the melt-textured YBCO superconductor demonstrate uneven distribution of Y atoms. Such a phenomenon can be explained by diffusion of Y atoms between the YBa 2Cu 3O y (Y-123)/liquid interface, the Y-211/liquid interface and the Y-211 grain inside. Moreover, 'gaps'-generated due to different degrees of contractions of the matrix and Y-211 grains are observed. 'Cavass' which is superconducting but appears like Y-211 grain is observed and reported.

Chow, J. C. L.; Fung, P. C. W.; Zhang, Y. H.

1995-03-01

12

12.141 Electron Microprobe Analysis by Wavelength Dispersive X-ray Spectrometry, January IAP 2010  

E-print Network

This lab-oriented course introduces the student to the subject of X-ray spectrometry and micro-scale chemical quantitative analysis of solid samples through an intensive series of hands-on laboratory exercises that use the ...

Chatterjee, Nilanjan

2010-01-01

13

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

14

Multielemental fast analysis of vegetation samples by wavelength dispersive X-ray fluorescence spectrometry: Possibilities and drawbacks  

NASA Astrophysics Data System (ADS)

X-ray fluorescence spectroscopy (XRF) is universally recognized as a non-destructive method for rapid and sequential, or simultaneous analysis of elemental composition of a material. The use of this technique for the direct determination of chemical elements in plant matrices has increased over the last few years. In the present study, a wavelength dispersive X-ray fluorescence (WDXRF) method for the quantitative analysis of some major elements (Na, Mg, Al, P, S, K, Ca), trace elements (Mn, Fe, Co, Zn, As) and non-essential elements (Sr, Pb) in vegetation specimens has been developed. The method uses a quick and easy sample preparation procedure since only drying, pulverizing and pressing of the samples are necessary. The calibration procedure was established by employing four plant reference materials and several synthetic cellulose calibrators spiked with appropriate amounts of analytes. Matrix effects were corrected employing the method of the influence coefficients on the basis of the computerized routine program linked to the equipment. Trueness of the experimental procedure was checked by using the standard reference material GBW07602 "Bush branches and leaves". In general, good agreement was achieved between certified values and the measured ones with recoveries ranging from 94% to 107%. Moreover, quality parameters, including repeatability and reproducibility of the developed method, were also evaluated. On the whole, from results obtained, WDXRF method proposed prove to be good and effective tool for environmental investigation and quality control processes in vegetation specimens.

Marguí, E.; Hidalgo, M.; Queralt, I.

2005-10-01

15

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

16

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

17

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

PubMed

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

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

2013-01-01

18

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. PMID:23254659

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

2013-01-01

19

Wavelength-dispersive total-reflection X-ray fluorescence with an efficient Johansson spectrometer and an undulator X-ray source: detection of 10-16 g-level trace metals.  

PubMed

The present paper reports significant enhancement of the detection power for total-reflection X-ray fluorescence (TXRF). The employment of an efficient wavelength-dispersive spectrometer rather than a conventional Si(Li) detector, as well as the use of a quasi-monochromatic undulator X-ray source, completely changed the quality of X-ray florescence spectra. The energy resolution is 20 times better, which effectively contributes to reducing the low-energy tail of the scattering background and to separating neighboring X-ray florescence peaks. Another advantage is its capability with respect to high-counting-rate measurements, which ensure the detection of weak signals from trace materials. The absolute and relative detection limit for nickel are 3.1 x 10(-16) g and 3.1 ppt (pg/g) for a 0.1-microL droplet of pure water, respectively, which is nearly 50 times better than the current best data achieved by conventional energy-dispersive TXRF using a Si(Li) detector system. PMID:12236366

Sakurai, Kenji; Eba, Hiromi; Inoue, Katsuaki; Yagi, Naoto

2002-09-01

20

Fabrication of high-throughput critical-angle X-ray transmission gratings for wavelength-dispersive spectroscopy  

E-print Network

The development of the critical-angle transmission (CAT) grating seeks both an order of magnitude improvement in the effective area, and a factor of three increase in the resolving power of future space-based, soft x-ray ...

Bruccoleri, Alexander Robert

2013-01-01

21

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

22

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

23

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

PubMed

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

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

2001-07-01

24

Determination of water-soluble hexavalent chromium in clinker samples by wavelength-dispersive X-ray fluorescence spectrometry after concentration in activated layers.  

PubMed

The determination of hexavalent chromium (Cr(VI)) in cement-related material extracts is frequently monitored in cement industries to comply with the European Directive (2003/53/EC) that limits the use of cements containing more than 2 mg kg(-1) of water-soluble Cr(VI). In the present work, a rapid and simple method for the determination of water-soluble Cr(VI) in clinker samples has been developed. The analytical methodology is based on the combined use of a low cost Cr(VI) isolation procedure using activated layers followed by their analysis using wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry. WDXRF instrumentation is a common tool used for determining the chemical composition of all materials involved in cement production and also for the quality control of the products produced in cement and concrete factories. Therefore, the presented methodology does not imply the use of additional instrumentation in cement-industries laboratories and can be used as a comparative method to the spectrophotometric reference (EN 196-10:2006). The analytical parameters evaluated (selectivity, limit of detection, linearity, and precision) prove to be suitable for the intended purpose, and the methodology has successfully been applied to determine water-soluble Cr(VI) in several clinker samples. PMID:20482975

Marguí, Eva; Fontàs, Claudia; Toribio, Marta; Guillem, Manel; Hidalgo, Manuela; Queralt, Ignacio

2010-05-01

25

Dispersive XAFS Image Radiograph by Parametric X-ray Radiation  

NASA Astrophysics Data System (ADS)

The parametric X-ray (PXR) generator system at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University is a variable-wavelength and quasi-monochromatic X-ray source, which was developed as one of the advance applications of the 125-MeV electron linear accelerator. Since the first observation of the X-rays generated by the system in April 2004, application studies have been performed using the PXR beam in the region from 6.0 to 20keV. The PXR beam extracted from the fixed output port of the generator has characteristic energy dispersion. The theoretical energy spread at the output port with an inner diameter of 98mm changes approximately from 300eV to 2keV depending on central X-ray energy from 7keV and 20keV. The dispersion occurs linearly only in horizontal direction, with a high energy resolution. The characteristics of the PXR beam from the generator suggest a possibility of for the kind of energy dispersive X-ray absorption fine structure (DXAFS) measurement using density distribution in the radiographs of materials. Using the uniform film of the sample materials, DXAFS can be deduced from the measurement of the horizontal density distribution in the radiograph due to the characteristics of the PXR beam. Since the PXR generator system is based on the S-band liner accelerator, it has the potential for the time-resolved XAFS measurement with several ten pico-second resolutions.

Mori, Akira; Hayakawa, Yasushi; Sato, Isamu; Tanaka, Toshinari; Hayakawa, Ken; Kuwada, Takao; Kobayashi, Koji; Ohshima, Hisashi

2007-01-01

26

Wavelength Dispersive X-ray Fluorescence Introduction  

E-print Network

resolution. WDX spectrometers with simple electronic counting circuits were around well before the computer on for the systems resolution it can be a proportional counter or other low- resolution counter capable of detecting another may be measured in sequence. This type of instrument is a sequential WDX analyzer. There are also

Wells, Mathew G. - Department of Physical and Environmental Sciences, University of Toronto

27

Single atom identification by energy dispersive x-ray spectroscopy  

SciTech Connect

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

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

2012-04-09

28

Focusing Collector for Long Wavelength X-Ray Astronomy.  

National Technical Information Service (NTIS)

A study has been made of the low-energy diffuse x-ray radiation with a rocketborne instrument that is completely insensitive to electrons and high-energy x rays. The detector employs a thin polypropylene window, methane counting gas, and a number of indep...

D. Mitchell, D. J. Yentis, J. R. P. Angel, P. V. Bout, R. Novick

1971-01-01

29

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

SciTech Connect

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

Worley, Christopher G [Los Alamos National Laboratory

2009-01-01

30

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

SciTech Connect

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

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

2007-08-24

31

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

SciTech Connect

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

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

2008-09-24

32

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

DOEpatents

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

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

1985-01-01

33

High Resolution, Non-Dispersive X-Ray Calorimeter Spectrometers on EBITs and Orbiting Observatories  

NASA Technical Reports Server (NTRS)

X-ray spectroscopy is the primary tool for performing atomic physics with Electron beam ion trap (EBITs). X-ray instruments have generally fallen into two general categories, 1) dispersive instruments with very high spectral resolving powers but limited spectral range, limited count rates, and require an entrance slit, generally, for EBITs, defined by the electron beam itself, and 2) non-dispersive solid-state detectors with much lower spectral resolving powers but that have a broad dynamic range, high count rate ability and do not require a slit. Both of these approaches have compromises that limit the type and efficiency of measurements that can be performed. In 1984 NASA initiated a program to produce a non-dispersive instrument with high spectral resolving power for x-ray astrophysics based on the cryogenic x-ray calorimeter. This program produced the XRS non-dispersive spectrometers on the Astro-E, Astro-E2 (Suzaku) orbiting observatories, the SXS instrument on the Astro-H observatory, and the planned XMS instrument on the International X-ray Observatory. Complimenting these spaceflight programs, a permanent high-resolution x-ray calorimeter spectrometer, the XRS/EBIT, was installed on the LLNL EBIT in 2000. This unique instrument was upgraded to a spectral resolving power of 1000 at 6 keV in 2003 and replaced by a nearly autonomous production-class spectrometer, the EBIT Calorimeter Spectrometer (ECS), in 2007. The ECS spectrometer has a simultaneous bandpass from 0.07 to over 100 keV with a spectral resolving power of 1300 at 6 keV with unit quantum efficiency, and 1900 at 60 keV with a quantum efficiency of 30%. X-ray calorimeters are event based, single photon spectrometers with event time tagging to better than 10 us. We are currently developing a follow-on instrument based on a newer generation of x-ray calorimeters with a spectral resolving power of 3000 at 6 keV, and improved timing and measurement cadence. The unique capabilities of the x-ray calorimeter spectrometer, coupled with higher spectral resolution dispersive spectrometers to resolve line blends, has enabled many science investigations, to date mostly in our x-ray laboratory astrophysics program. These include measurements of absolute cross sections for Land K shell emission from Fe and Ni, charge exchange measurements in many astrophysically abundant elements, lifetime measurements, line ratios, and wavelength measurements. In addition, we have performed many additional measurements in nuclear physics, and in support of diagnostics for laser fusion, for example. In this presentation we will give a detailed overview of x-ray calorimeter instruments in general and in our EBIT laboratory astrophysics program in particular. We will also discuss the science yield of our measurements at EBIT over the last decade) prospects for future science enabled by the current generation of spectrometers and that will be expanded in the near future by the next generation of spectrometers starting in 2611.

Porter, Frederick S.

2010-01-01

34

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

PubMed

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

Newbury, Dale E; Ritchie, Nicholas W M

2013-01-01

35

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

36

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

NASA Astrophysics Data System (ADS)

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

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

2005-07-01

37

Multi-wavelength studies of ultra luminous X-ray sources in NGC1427  

NASA Astrophysics Data System (ADS)

We present the results on the multi-wavelength studies of point sources and ultra luminous X-ray sources (ULXs) in NGC 1427 using the Chandra, Hubble Space Telescope (HST) and Spitzer missions. NGC 1427 is an elliptical galaxy in Fornax cluster, 13 X-ray sources with net counts >50 have been identified by Chandra observation in 2005. Most of the X-ray sources are well fitted with disk black body than power law model and its X-ray luminosity reaches the ULXs range. We searched for the optical counterparts to these sources in HST archival images and studied the variability. Out of 13 sources, four sources are in the field of view of HST and three of them having potential optical counterparts within less than two arc-seconds. One of the optical counterparts of ULXs exhibits a significant variability of ˜0.3 magnitude between two F475W observations separated by 22 months. While, other counterparts are not variable in the same time scale. Also, these sources are blue in (g-z) colors and their optical luminosity are comparable to the X-ray ones. For some sources, the optical luminosity exceeds the X-ray luminosity. The optical magnitude difference is higher than the reported case of ULXs, indicating that the optical variability connected to the X-ray activity.

Jithesh, V.; Preetha, A. U.; Misra, R.; Ravindranath, S.; Dewangan, Gulab C.; Ravikumar, C. D.; Jeena, K.; Babu, B. R. S.

38

Optimization of reflectivity of periodic and quasiperiodic multilayer films at soft X-ray wavelengths  

NASA Astrophysics Data System (ADS)

The reflectivity of multilayer films consisting of alternating layers of high and low refractive index is investigated. It is found that the thickness of periods affects the optimized reflectivity, and that a quasi-periodic structure with fixed thickness of periods but changing thicknesses of the layers can form two reflecting peaks at different wavelength positions. The result can be used to increase the bandwidth and to change the shape of reflectivity curves in the soft X-ray region. Since nonabsorbing material does not exist in the soft X-ray region, the thickness of each layer should be optimized separately in order to obtain maximum reflectivity at a single wavelength.

Gu, E.; Marr, G. V.; Player, M. A.

1990-06-01

39

X-Ray Sources with No Counterparts in Other Wavelength Bands  

NASA Astrophysics Data System (ADS)

In order to identify peculiar X-ray sources, we select 442 sources with no counterparts in other wavelength bands (as of the year 1999) from the ROSAT All-Sky Survey Bright Source Catalog. We cross-correlate this initial list with the NASA/IPAC Extragalactic Database, the USNO and WISE catalogs, and the HEASARC XRAY Master Catalog. Eventually, we are left with four unidentified sources with no counterparts in other wavelength bands. We present these four sources and their X-ray properties in this paper.

Kim, Chulhee; Moon, Byung-Kwon; Park, Hong Soo

2014-10-01

40

TRANSIT OBSERVATIONS OF THE HOT JUPITER HD 189733b AT X-RAY WAVELENGTHS  

SciTech Connect

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 L{sub X} = 26.67 erg s{sup -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.; Wolk, S. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Schmitt, J. H. M. M., E-mail: kpoppenhaeger@cfa.harvard.edu [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)

2013-08-10

41

X-ray flux concentrating optics for improving the performance of light element energy dispersive spectroscopy  

Microsoft Academic Search

Frequently, EDS (Energy Dispersive Spectrometer) x-ray detectors cannot be placed very close to an x-ray source for microanalysis causing the detector to subtend a small solid angle thus reducing the available count rate. This is exacerbated by low count rates for the light elements and situations where low energy spectral lines are immersed in a background of higher energy x-rays

David B. O'Hara

1998-01-01

42

Study of Microflares at Hard X-ray and Microwave Wavelengths  

Microsoft Academic Search

We present the preliminary results of studying microflares at hard X-ray and microwave wavelengths which are observed by Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Owens Valley Solar Array (OVSA). Among over 700 microflare bursts that are observed by RHESSI during the open-shutter mode from May to September in 2002, more than 200 fall into the OVSA observing time

J. Qiu; D. E. Gary; C. Liu; H. Wang

2003-01-01

43

Conventional wavelength dispersive spectroscopy versus parallel beam spectroscopy – a basic overview  

Microsoft Academic Search

.  This article gives a summary of currently available wavelength dispersive spectroscopy techniques on the market, explains\\u000a technical differences and advantages as well as limitations of conventional wavelength dispersive spectroscopy versus parallel\\u000a beam wavelength spectroscopy. In addition to the energy dispersive and traditional wavelength spectroscopy technique, the\\u000a parallel beam spectroscopy opens new wavelength applications. It enables X-ray microanalysis with wavelength advantages

Corrie van Hoek; Max Koolwijk

2008-01-01

44

Wavelength calibration of x-ray imaging crystal spectrometer on Joint Texas Experimental Tokamaka)  

NASA Astrophysics Data System (ADS)

The wavelength calibration of x-ray imaging crystal spectrometer is a key issue for the measurements of plasma rotation. For the lack of available standard radiation source near 3.95 Å and there is no other diagnostics to measure the core rotation for inter-calibration, an indirect method by using tokamak plasma itself has been applied on joint Texas experimental tokamak. It is found that the core toroidal rotation velocity is not zero during locked mode phase. This is consistent with the observation of small oscillations on soft x-ray signals and electron cyclotron emission during locked-mode phase.

Yan, W.; Chen, Z. Y.; Jin, W.; Huang, D. W.; Ding, Y. H.; Li, J. C.; Zhang, X. Q.; Lee, S. G.; Shi, Y. J.; Zhuang, G.

2014-11-01

45

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

46

Accounting for the dispersion in the x ray properties of early-type galaxies  

NASA Technical Reports Server (NTRS)

The x ray luminosities of early-type galaxies are correlated with their optical (e.g., blue) luminosities (L sub X approx. L sub B exp 1.6), but the x ray luminosities exhibit considerable scatter for a given optical luminosity L sub B. This dispersion in x ray luminosity is much greater than the dispersion of other properties of early-type galaxies (for a given L sub B), such as luminosity scale-length, velocity dispersion, color, and metallicity. Here, researchers consider several possible sources for the dispersion in x ray luminosity. Some of the scatter in x ray luminosity may result from stellar population variations between galaxies with similar L sub B. Since the x ray emitting gas is from accumulated stellar mass loss, the L sub X dispersion may be due to variations in integrated stellar mass loss rates. Another possible cause of the L sub X dispersion may be variations in the amount of cool material in the galaxies; cool gas may act as an energy sink for the hot gas. Infrared emission may be used to trace such cool material, so researchers look for a correlation between the infrared emission and the x ray emission of early-type galaxies at fixed L sub B. Velocity dispersion variations between galaxies of similar L sub B may also contribute to the L sub X dispersion. The most likely a priori source of the dispersion in L sub X is probably the varying amount of ram-pressure stripping in a range of galaxy environments. The hot gaseous halos of early-type galaxies can be stripped in encounters with other galaxies or with ambient cluster gas if the intracluster gas is sufficiently dense. Researchers find that the most likely cause of dispersion in the x ray properties of early type galaxies is probably the ram-pressure stripping of gaseous halos from galaxies. For a sample of 81 early-type galaxies with x ray luminosities or upper limits derived from Einstein Observatory observations (CFT) researchers calculated the cumulative distribution of angular distances between the x ray sample members and bright galaxies from the Revised Shapley - Ames catalog. Collectively, galaxies with low x ray luminosities (for a given L sub B) tend to be in denser environments than galaxies with higher x ray luminosities.

White, Raymond E., III; Sarazin, Craig L.

1990-01-01

47

Superconducting Tunnel Junction Array Development for High-Resolution Energy-Dispersive X-ray Spectroscopy  

Microsoft Academic Search

: Cryogenic energy-dispersive X-ray detectors are being developed because of their superior energy resolution (10 eV FWHM for keV X-rays) compared to that achieved in semiconductor energy-dispersive spectrometry (EDS) systems. So far, their range of application is limited because of their comparably small size and low count rate. We present data on the development of superconducting tunnel junction (STJ) detector

S. Friedrich; C. A. Mears; B. Nideröst; L. J. Hiller; M. Frank; S. E. Labov; A. T. Barfknecht; S. P. Cramer

1998-01-01

48

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

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

49

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

50

Rest-wavelength fiducials for the ITER core imaging x-ray spectrometera)  

NASA Astrophysics Data System (ADS)

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 L?3 line and the Ir L?2 line, which bracket the W64+ 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 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.

2012-10-01

51

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

52

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

53

X-ray reflectivity measurements of surface roughness using energy dispersive detection  

SciTech Connect

We describe a new technique for measuring x-ray reflectivity using energy dispersive x-ray detection. The benefits of this method are the use of a fixed scattering angle and parallel detection of all energies simultaneously. These advantages make the technique more readily useable with laboratory x-ray sources and more compatible with growth chambers. We find excellent agreement between the calculated Fresnel reflectivity and the reflectivity obtained from a smooth Ge (001) surface. Reflectivities obtained during 500 eV Xe ion bombardment of Ge surfaces demonstrate the sensitivity of the technique to be better than 1 {angstrom}. 9 refs., 4 figs.

Chason, E.; Warwick, D.T.

1990-01-01

54

Dispersive spread of virtual sources by asymmetricX-ray monochromators  

SciTech Connect

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

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

2012-01-26

55

Self-consistent absorption corrections for low-energy X-ray lines in energy-dispersive X-ray spectroscopy  

Microsoft Academic Search

Quantification of energy-dispersive X-ray spectra in transmission electron microscopy is often unreliable for X-ray lines of low energy, as they are subject to strong absorption and fluorescence corrections which will depend critically on both the sample thickness and the detector properties (take-off angle, detector material and type, thickness and cleanliness of any detector window). By using the method to vary

M C Parri; T Walther

2012-01-01

56

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

NASA Astrophysics Data System (ADS)

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

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

2007-01-01

57

Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-Ray (EDX) Spectroscopy  

E-print Network

Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-Ray (EDX) Spectroscopy Microscope (FE-SEM) as shown in Figure 1. The FE-SEM combines the versatility of PC control with a novel mm working distance. The FE-SEM also offers excellent low kV performance with resolution of 2.5 nm

Gelfond, Michael

58

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

E-print Network

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

Paris-Sud XI, Université de

59

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

60

Interfacial energy-dispersive spectroscopy profile X-ray resolution measurements in variable pressure SEM.  

PubMed

A procedure has been developed to follow degradation of energy-dispersive spectroscopy (EDS) X-ray lateral resolution in a variable pressure scanning electron microscope. This procedure is based on evaluation of the EDS profile shape change for different experimental conditions. Some parameters affecting the X-ray resolution in high-vacuum mode have been taken into account. Good agreement between the simulated and experimental EDS profiles shows the reliability of the proposed procedure. A significant improvement in measurement of the EDS profile interfacial distance (DINT) has been achieved. PMID:24960537

Zoukel, Abdelhalim; Khouchaf, Lahcen; Di Martino, Jean; Ruch, David

2014-10-01

61

Place of HgI/sub 2/ energy-dispersive x-ray detectors  

SciTech Connect

After a review of solid-state conduction counters, in general, and of the history of mercuric iodide, in particular, the theory of operation of solid-state energy-dispersive HgI/sub 2/ detectors is dicusssed. The main factors which limit energy resolution in solid-state compound detectors are considered, including statistical fluctuations in charge generation, the window effect, trapping, inhomogeneities in the detector material, and electronic noise. Potential applications of room-temperature HgI/sub 2/ x-ray detectors are listed, and general considerations are discussed for x-ray fluorescence analysis with HgI/sub 2/. Directions of current investigations are given. (LEW)

Dabrowski, A.J.; Huth, G.C.; Iwanczyk, J.S.; Kusmiss, J.H.; Barton, J.S.; Szymczyk, J.M.; Schnepple, W.F.; Lynn, R.

1982-01-01

62

The 20 element HgI2 energy dispersive x ray array detector system  

NASA Astrophysics Data System (ADS)

This paper describes recent progress in the development of HgI2 energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K(sub a)) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel.

Iwanczyk, J. A.; Dorri, N.; Wang, M.; Szczebiot, R. W.; Dabrowski, A. J.; Hedman, B.; Hodgson, K. O.; Patt, B. E.

1991-11-01

63

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

64

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

E-print Network

At-wavelength and optical metrology of bendable x-ray optics for nanofocusing at the ALS Sheng Yuan-wavelength and conventional optical metrology techniques suitable to characterize the surface profile of super-high-quality x of these techniques with high precision optical metrology and experimental methods [2] will enable us to provide

65

The use of a single wavelength wiggler in PEP as a circular polarized hard X-ray source  

Microsoft Academic Search

Three single-wavelength planar wigglers have been installed in the positron-electron project (PEP) storage ring in order to obtain better luminosities for high-energy physics. Two of them are located next to the X-ray undulators and can be used as synchrotron radiation sources, providing circularly polarized hard X-rays, without any major changes of the lattice and beam lines during dedicated operation of

Shigemi Sasaki; Bradley Youngman; Herman Winick

1990-01-01

66

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

67

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

68

Energy dispersive X-ray spectroscopy analysis on rock samples subjected to piezonuclear tests  

Microsoft Academic Search

\\u000a In the present paper, Energy Dispersive X-ray Spectroscopy (EDS) was performed on different samples of external or fracture\\u000a surfaces coming from specimens used in piezonuclear tests [1,2]. For each sample, different measurements of the same crystalline\\u000a phases (phengite and biotite) were performed in order to get averaged information of the chemical composition and to detect\\u000a possible piezonuclear transmutations from iron

A. Carpinteri; A. Chiodoni; A. Manuello; R. Sandrone

69

Detection of chitosan in Scots pine by Energy Dispersive X-ray Spectroscopy  

Microsoft Academic Search

The aim of this study was to use Energy-Dispersive X-ray Spectroscopy (EDS) to localize chitosan in the cell wall of chitosan impregnated Scots pine. It is of both general and specific interest to investigate the concentration of chitosan in the wood matrix to gain further knowledge and understanding of chitosan as a wood protective system. After deacetylation, chitosan was re-acetylated

E. LARNØY; M. EIKENES; H. MILITZ

70

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

PubMed

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

Maalhagh-Fard, Ahmad; Wagner, Warren C

2004-09-01

71

Scanning electron microscope/energy dispersive x ray analysis of impact residues in LDEF tray clamps  

NASA Technical Reports Server (NTRS)

Detailed optical scanning of tray clamps is being conducted in the Facility for the Optical Inspection of Large Surfaces at JSC to locate and document impacts as small as 40 microns in diameter. Residues from selected impacts are then being characterized by Scanning Electron Microscopy/Energy Dispersive X-ray Analysis at CNES. Results from this analysis will be the initial step to classifying projectile residues into specific sources.

Bernhard, Ronald P.; Durin, Christian; Zolensky, Michael E.

1993-01-01

72

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

73

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

74

THE CORRELATION BETWEEN DISPERSION MEASURE AND X-RAY COLUMN DENSITY FROM RADIO PULSARS  

SciTech Connect

Pulsars are remarkable objects that emit across the entire electromagnetic spectrum, providing a powerful probe of the interstellar medium. In this study, we investigate the relation between dispersion measure (DM) and X-ray absorption column density N{sub H} using 68 radio pulsars detected at X-ray energies with the Chandra X-Ray Observatory or XMM-Newton. We find a best-fit empirical linear relation of N{sub H} (10{sup 20} cm{sup -2})= 0.30{sup +0.13}{sub -0.09} DM (pc cm{sup -3}), which corresponds to an average ionization of 10{sup +4}{sub -3}%, confirming the ratio of one free electron per 10 neutral hydrogen atoms commonly assumed in the literature. We also compare different N{sub H} estimates and note that some N{sub H} values obtained from X-ray observations are higher than the total Galactic H I column density along the same line of sight, while the optical extinction generally gives the best N{sub H} predictions.

He, C.; Ng, C.-Y.; Kaspi, V. M., E-mail: ncy@bohr.physics.hku.hk [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada)

2013-05-01

75

Airborne particles in the Miyagi Museum of Art in Sendai, Japan, studied by electron probe X-ray microanalysis and energy dispersive X-ray fluorescence analysis.  

PubMed

The presented work provides baseline data on the existing airborne conditions in the Miyagi Museum of Art in Sendai, Japan, during the summer of 2000. The chemical composition, size and indoor and outdoor origin of the suspended particulate matter were identified using a number of advanced X-ray techniques, such as Electron Probe X-Ray Microanalysis (EPXMA) and Energy Dispersive X-Ray Fluorescence Analysis (EDXRF). Our results, to the best of our knowledge, represent the first detailed study of the chemical nature of the indoor particulate matter in a Japanese museum and, as such, may contribute to future improvements of the air quality inside museums and to the lasting conservation of works of art. PMID:12036125

Injuk, Jasna; Osán, Janos; Van Grieken, René; Tsuji, Kouichi

2002-05-01

76

CUBIC - A non-dispersive Diffuse X-ray Background spectrometer. [Cosmic Unresolved X-ray Background Instrument  

NASA Technical Reports Server (NTRS)

The Cosmic Unresolved X-ray Background Instrument using CCDs (CUBIC) is designed to obtain spectral observations of the Diffuse X-ray Background (DXRB) with moderate spectral resolution over the energy range 0.2-10 keV, using mechanically-collimated CCDs. At this time, it is the only planned satellite payload devoted to the study of the spectrum of the DXRB. Over the anticipated 3 year lifetime of the satellite, CUBIC will be able to study up to 50 percent of the sky with 5 x 5 deg spatial resolution for the subkilovolt Galactic diffuse background, and with 10 x 10 deg spatial resolution for the extragalactic diffuse background above 2 keV. CUBIC will obtain high quality nondispersive spectra of soft X-ray emission from the interstellar medium, supernova remnants, and some bright sources, and will make a sensitive seach for line emission or other features in the extragalactic cosmic X-ray background from 2-10 keV.

Burrows, David N.; Skinner, Mark A.; Antunes, Alexander J. D.; Catalano, Mark A.; Cocklin, Eric J.; Engel, Leland G.; Entingh, Timothy J.; Garmire, Gordon P.; Green, Roland; Kelly, Douglas A.

1992-01-01

77

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

PubMed

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

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

2009-12-01

78

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. PMID:19920884

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

2009-01-01

79

MULTI-WAVELENGTH OBSERVATIONS OF SOLAR FLARES WITH A CONSTRAINED PEAK X-RAY FLUX  

SciTech Connect

We present an analysis of soft X-ray (SXR) and extreme-ultraviolet (EUV) observations of solar flares with an approximate C8 Geostationary Operational Environmental Satellite (GOES) class. Our constraint on peak GOES SXR flux allows for the investigation of correlations between various flare parameters. We show that the duration of the decay phase of a flare is proportional to the duration of its rise phase. Additionally, we show significant correlations between the radiation emitted in the flare rise and decay phases. These results suggest that the total radiated energy of a given flare is proportional to the energy radiated during the rise phase alone. This partitioning of radiated energy between the rise and decay phases is observed in both SXR and EUV wavelengths. Though observations from the EUV Variability Experiment show significant variation in the behavior of individual EUV spectral lines during different C8 events, this work suggests that broadband EUV emission is well constrained. Furthermore, GOES and Atmospheric Imaging Assembly data allow us to determine several thermal parameters (e.g., temperature, volume, density, and emission measure) for the flares within our sample. Analysis of these parameters demonstrate that, within this constrained GOES class, the longer duration solar flares are cooler events with larger volumes capable of emitting vast amounts of radiation. The shortest C8 flares are typically the hottest events, smaller in physical size, and have lower associated total energies. These relationships are directly comparable with several scaling laws and flare loop models.

Bowen, Trevor A.; Testa, Paola; Reeves, Katharine K., E-mail: tbowen@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 58, Cambridge, MA 02138 (United States)

2013-06-20

80

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

81

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

SciTech Connect

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

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

2011-11-28

82

The X-ray Luminosity - Velocity Dispersion relation in the REFLEX Cluster Survey  

E-print Network

We present an estimate of the bolometric X-ray luminosity - velocity dispersion L_x - sigma_v relation measured from a new, large and homogeneous sample of 171 low redshift, X-ray selected galaxy clusters. The linear fitting of log(L_x) - log(sigma_v) gives L_x = 10^{32.72 \\pm 0.08} sigma^{4.1 \\pm 0.3}_v erg s^{-1} h^{-2}_{50}. Furthermore, a study of 54 clusters, for which the X-ray temperature of the intracluster medium T is available, allows us to explore two other scaling relations, L_x -T and sigma_v -T. From this sample we obtain L_x \\propto T^{3.1 \\pm 0.2} and sigma_v \\propto T^{1.00 \\pm 0.16}, which are fully consistent with the above result for the L_x-sigma_v. The slopes of L_x -T and sigma_v -T are incompatible with the values predicted by self-similarity (L_x \\propto T^{2} \\propto \\sigma_v^4), thus suggesting the presence of non-gravitational energy sources heating up the intracluster medium, in addition to the gravitational collapse, in the early stages of cluster formation. On the other hand, the result on log(L_x) - log(sigma_v) supports the self-similar model.

A. Ortiz-Gil; L. Guzzo; P. Schuecker; H. Boehringer; C. A. Collins

2003-11-05

83

[Application of in situ micro energy dispersive X-ray fluorescence analysis in mineralogy].  

PubMed

Thirteen rock samples were collected for studying the variation of element content in the mineral during the alteration process from Xinjiang, China. The IED-6000 in situ micro energy dispersive X-ray fluorescence developed by CDUT was applied to get chemical and physical data from minerals. The non-destructive spectrometer is based on a low-power Mo-anode X-ray tube and a Si-PIN peltier cooled X-ray detector. The unique design of the tube's probe allows very close coupling of polycapillary and makes the use of micro-area measurement feasible and efficient. The spectrometer can be integrated into any microscope for analysis. The long axis diameter of beam spot is about 110 microm. According to micro-EDXRF measurement, the tetrahedrite was corrected to pyrite, improving the efficiency and accuracy of the mineral identification. The feldspar of mineralized rock sample is rich in Cu and Zn which can be used as prospecting indicator elements. Element content of Cr, Mn and Co shows negative correlation with the degree of mineralization. PMID:24555398

Yang, Hai; Ge, Liang-Quan; Gu, Yi; Zhang, Qing-Xian; Xiong, Sheng-Qing

2013-11-01

84

A method to test the performance of an energy-dispersive X-ray spectrometer (EDS).  

PubMed

A test material for routine performance evaluation of energy-dispersive X-ray spectrometers (EDS) is presented. It consists of a synthetic, thick coating of C, Al, Mn, Cu, and Zr, in an elemental composition that provides interference-free characteristic X-ray lines of similar intensities at 10 kV scanning electron microscope voltage. The EDS energy resolution at the C-K, Mn-L?, Cu-L?, Al-K, Zr-L?, and Mn-K? lines, the calibration state of the energy scale, and the Mn-L?/Mn-K? intensity ratio as a measure for the low-energy detection efficiency are calculated by a dedicated software package from the 10 kV spectrum. Measurements at various input count rates and processor shaping times enable an estimation of the operation conditions for which the X-ray spectrum is not yet corrupted by pile-up events. Representative examples of EDS systems characterized with the test material and the related software are presented and discussed. PMID:25033259

Hodoroaba, Vasile-Dan; Procop, Mathias

2014-10-01

85

Energy dispersive x-ray analysis in the study of pneumoconiosis.  

PubMed Central

Identification of inorganic substances in the lung is an important step towards the establishment of a cause and effect relationship in the study of pneumoconiosis. The conventional methods for this identification usually require an ashing which makes it difficult to study the localisation of these substances in relation to pathology. A method is described to identify foreign substances in the tissue obtained either on biopsy or autopsy without destroying them. The technique employs scanning electron microscopy together with energy dispersive x-ray analysis. This method not only allows simultaneous multi-elemental analysis of over 80 elements, but also permits detailed morphological examination while the tissue is being analysed. Images PMID:871449

Funahashi, A; Siegesmund, K A; Dragen, R F; Pintar, K

1977-01-01

86

Application of energy dispersive X-ray fluorescence spectrometry (EDX) in a case of methomyl ingestion.  

PubMed

We applied energy dispersive X-ray fluorescence spectrometry (EDX) in a case of poisoning by methomyl, a carbamate pesticide. Quantitative GC/MS analysis showed that the concentration of methomyl-oxime in the femoral blood was 4.0 ?g/ml. The elemental analysis by EDX identified the high peak of silicon and sulfur in the stomach contents. We concluded that the cause of his death was methomyl poisoning. This indicates that screening of stomach contents by EDX provides useful information for the forensic diagnosis. PMID:22999231

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

2013-04-10

87

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

88

A Multi-Wavelength Study of the X-Ray Sources in the NGC 5018  

NASA Technical Reports Server (NTRS)

The E3 giant elliptical galaxy NGC-5018 was observed with the cxo X-ray Observatory's Advanced CCD Imaging Spectrometer for 30-h on 14 April 2001. Results of analysis of these X-ray data as well as of complementary optical, infrared, and radio data are reported. Seven X-ray point sources, including the nucleus, were detected. If they are intrinsic to NGC-5018, then all six non-nuclear sources have luminosities exceeding 10(exp 39)-ergl in the 0.5-8.0-keV energy band; placing them in the class of Ultra- luminous X-ray sources. Comparison of X-ray source positions to archival Hubble Space Telescope/Wide Field Planetary Camera 2 (hst/WFPC2) images reveal four of the six non-nuclear sources are spatially--coincident with bright, M$(sub V)LA -8.6 mag, objects. These four objects have optical magnitudes and (V-I) colors consistent with globular clusters in NGC-5018. However, one of these objects was observed to vary by siml mag in both V and I between observations taken 28 July 1997 and 04 Feb 1999 indicating this source is a background active galactic nucleus (AGN). The nature of the other three optically-bright objects cannot be determined from the available optical data but all have X-ray-to-optical flux ratios consistent with background AGNs. Strong, unpolarized, radio emission has been detected from another of the optically-bright counterparts. It displays an inverted radio spectrum and is the most absorbed of the seven sources in the X-ray band. It, too, is most readily explained as a background AGN, though alternative explanations cannot be ruled out. Extended X-ray emission is detected within a siml5 arcsec radius of the galaxy center at a luminosity of sim lO(exp 40)-ergl in the X-ray band. Its thermal X-ray spectrum (kT sim0.4-keV) and its spatial coincidence with strong H(alpha) emission are consistent with a hot gas origin. The nucleus itself is a weak X-ray source, LA-5 times 10(exp 39)-ergl, but displays a radio spectrum typical of AGN.

Ghosh, Kajal K.; Swartz, Douglas A.; Tennant, Allyn F.; Wu, Kinwah; Saripalli, Lakshmi

2004-01-01

89

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

90

Inelastic x-ray scattering study of plasmon dispersions in solid and liquid Rb  

NASA Astrophysics Data System (ADS)

The plasmon dispersion relations in solid and liquid Rb were determined by inelastic x-ray scattering techniques. In liquid Rb, the plasmon energy increases with the momentum transfer q, whereas in solid Rb, the dispersion curve exhibits a cusplike shape. We also found that the plasmon linewidth in liquid Rb is narrower than that in solid Rb near q =0. These features suggest that the conduction electrons in liquid Rb are more suitably described by the electron gas model than in solid Rb, since the electron gas model predicts a smooth increase in the plasmon energy with q and the infinite lifetime at q =0. The origins of the observed variations in the plasmon energy and the linewidth upon melting are investigated with the aid of theoretical calculations.

Kimura, K.; Matsuda, K.; Hiraoka, N.; Fukumaru, T.; Kajihara, Y.; Inui, M.; Yao, M.

2014-01-01

91

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

92

A Multi-wavelength study of the Pulsar PSR B1929+10 and its X-ray trail  

E-print Network

We report on the emission properties of PSR B1929+10 and its putative X-ray trail from a multi-wavelength study performed with XMM-Newton, the ESO NTT, the HST, the Effelsberg 100m Radio Telescope and the Jodrell Bank Radio Observatory. The XMM-Newton observations confirm the existence of the diffuse emission with a trail morphology lying in a direction opposite to the transverse motion of the pulsar. The trail has a length of ~15 arcmin. Its spectrum is non-thermal and produced by electron-synchrotron emission in the shock between the pulsar wind and the surrounding medium. Assuming that the electron lifetime against synchrotron cooling is comparable to the source transit time over the X-ray trail length, the magnetic field strength in the trail emitting region is inferred to be ~5 uG. Inspecting data from the Effelsberg 11cm radio continuum survey of the Galactic plane we discovered an elongated feature apparently coincident with the X-ray trail. The emission properties observed from PSR 1929+10 are found to finally challenge the picture of the emission properties of old non-recycled rotation powered pulsars. Both, the temporal and spectral X-ray emission properties of PSR 1929+10 are in excellent agreement with a non-thermal and, thus, magnetospheric radiation dominated emission scenario. A flux contribution from the thermal emission of heated polar caps of ~7% is inferred from a best fitting composite Planckian and power law spectral model. The X-ray pulse profile is found to be markedly different from the broad sinusoidal pulse profile seen in the low statistic ROSAT data. Simulations in the framework of an outer-gap emission model are able to reproduce the observed X-ray pulse profile and its phase relation relative to the radio pulse.

Werner Becker; Michael Kramer; Axel Jessner; Ronald E. Taam; Jian J. Jia; Kwong S. Cheng; Roberto Mignani; Alberto Pellizzoni; Andrea de Luca; Agnieszka Slowikowska; Patrizia Caraveo

2005-06-22

93

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

NASA Astrophysics Data System (ADS)

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, Brendan A.; Berrill, Mark; Wernsing, Keith A.; Baumgarten, Cory; Woolston, Mark; Rocca, Jorge J.

2014-05-01

94

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

NASA Astrophysics Data System (ADS)

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

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

2002-07-01

95

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

96

Studying Dark Energy, Black Holes and Cosmic Feedback at X-ray Wavelengths: NASA's Constellation-X Mission  

NASA Technical Reports Server (NTRS)

Among the most important topics in modern astrophysics are the nature of the dark energy equation of state, the formation and evolution of supermassive black holes in concert with galaxy bulges, and the self-regulating symmetry imposed by both stellar and AGN feedback. All of these topics are readily addressed with observations at X-ray wavelengths. For instance, theoretical models predict that the majority (98%) of the energy and metal content in starburst superwinds exists in the hot million-degree gas. The Constellation-X observatory is being developed to perform spatially resolved high-resolution X-ray spectroscopy so that we may directly measure the absolute element abundances and velocities of this hot gas. This talk focuses on the driving science behind this mission, which is one of two flagship missions in NASA's Beyond Einstein program. A general overview of the observatory's capabilities and basic technology will also be given.

Hornschemeier, A.

2005-01-01

97

Examination of Early Wear Detection in Diesel Engines by Energy Dispersive Radioisotope X Ray Fluorescence Analysis Untersuchungen Zur Schadensfrueherkennung bei Dieselmotoren MIT Hilfe der Energiedispersiven Radionuklid-Roentgenfluoreszenzanalyse.  

National Technical Information Service (NTIS)

The application of X-ray spectroscopy for monitoring wear-metal particles in lubricating oils is considered. The principles of an energy dispersive X-ray analytical arrangement consisting of radioistope sources or small, thin target, X-ray tubes for excit...

H. Meier, E. Unger, W. Albrecht, N. Geheeb, W. Hecker

1979-01-01

98

Gamma-ray bursts at near-IR\\/optical\\/X-ray wavelengths  

Microsoft Academic Search

GRBs remained a puzzle for many high-energy astrophysicists since their dis- covery in 1967, but with the advent of X-ray satellites like BSAX, RXTE and those of the Third Interplanetary Network, it has been possible since 1997 to discover the first opti- cal\\/IR counterparts just within a few hours of occurrence. This has greatly improved our understanding of these sources

A. J. Castro-Tirado

99

Gamma-ray bursts at near-IR\\/optical\\/X-ray wavelengths  

Microsoft Academic Search

GRBs remained a puzzle for many high-energy astrophysicists since their discovery in 1967, but with the advent of X-ray satellites like BSAX, RXTE and those of the Third Interplanetary Network, it has been possible since 1997 to discover the first optical\\/IR counterparts just within a few hours of occurrence. This has greatly improved our understanding of these sources and the

A. J. Castro-Tirado

2005-01-01

100

Scanning electron microscope/energy dispersive x ray analysis of impact residues on LDEF tray clamps  

NASA Technical Reports Server (NTRS)

To better understand the nature of particulates in low-Earth orbit (LEO), and their effects on spacecraft hardware, we are analyzing residues found in impacts on the Long Duration Exposure Facility (LDEF) tray clamps. LDEF experiment trays were held in place by 6 to 8 chromic-anodized aluminum (6061-T6) clamps that were fastened to the spacecraft frame using three stainless steel hex bolts. Each clamp exposed an area of approximately 58 sq cm (4.8 cm x 12.7 cm x .45 cm, minus the bolt coverage). Some 337 out of 774 LDEF tray clamps were archived at JSC and are available through the Meteoroid & Debris Special Investigation Group (M&D SIG). Optical scanning of clamps, starting with Bay/Row A01 and working toward H25, is being conducted at JSC to locate and document impacts as small as 40 microns. These impacts are then inspected by Scanning Electron Microscopy/Energy Dispersive X-ray Analysis (SEM/EDXA) to select those features which contain appreciable impact residue material. Based upon the composition of projectile remnants, and using criteria developed at JSC, we have made a preliminary discrimination between micrometeoroid and space debris residue-containing impact features. Presently, 13 impacts containing significant amounts of unmelted and semi-melted micrometeoritic residues were forwarded to Centre National d'Etudes Spatiales (CNES) in France. At the CNES facilities, the upgraded impacts were analyzed using a JEOL T330A SEM equipped with a NORAN Instruments, Voyager X-ray Analyzer. All residues were quantitatively characterized by composition (including oxygen and carbon) to help understand interplanetary dust as possibly being derived from comets and asteroids.

Bernhard, Ronald P.; Durin, Christian; Zolensky, Michael E.

1992-01-01

101

Sulfur speciation in hydrous experimental glasses of varying oxidation state - Results from measured wavelength shifts of sulfur X-rays  

NASA Technical Reports Server (NTRS)

The focusing geometry of an electron microprobe has been used to measure the wavelength shifts of sulfur X-rays from hydrous experimental melts synthesized at oxygen fugacities that range from near the iron-wustite buffer to the magnetite-hermatite buffer. It is found that the proportion of dissolved sulfur which is present as sulfate increases with increasing oxygen fugacity. It is noted that in natural melts that have equilibrated at or below fayalite-magnetite-quartz values of +1, sulfur is probably present mainly as S(2-).

Carroll, Michael R.; Rutherford, Malcolm J.

1988-01-01

102

X-ray Scattering Measurements of Particle Orientation in a Sheared Polymer/Clay Dispersion  

SciTech Connect

We report steady and transient measurements of particle orientation in a clay dispersion subjected to shear flow. An organically modified clay is dispersed in a Newtonian polymer matrix at a volume fraction of 0.02, using methods previously reported by Mobuchon et al. (Rheol Acta 46: 1045, 2007). In accord with prior studies, mechanical rheometry shows yield stress-like behavior in steady shear, while time dependent growth of modulus is observed following flow cessation. Measurements of flow-induced orientation in the flow-gradient plane of simple shear flow using small-angle and wide-angle X-ray scattering (SAXS and WAXS) are reported. Both SAXS and WAXS reveal increasing particle orientation as shear rate is increased. Partial relaxation of nanoparticle orientation upon flow cessation is well correlated with time-dependent changes in complex modulus. SAXS and WAXS data provide qualitatively similar results; however, some quantitative differences are attributed to differences in the length scales probed by these techniques.

Pujari, Saswati; Dougherty, Leah; Mobuchon, Christoph; Carreau, Pierre J.; Heuzey, Marie-Claude; Burghardt, Wesley R. (Ecole); (NWU); (Ecole)

2012-01-20

103

Rigorous quantitative elemental microanalysis by scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS) with spectrum processing by NIST DTSA-II  

NASA Astrophysics Data System (ADS)

Quantitative electron-excited x-ray microanalysis by scanning electron microscopy/silicon drift detector energy dispersive x-ray spectrometry (SEM/SDD-EDS) is capable of achieving high accuracy and high precision equivalent to that of the high spectral resolution wavelength dispersive x-ray spectrometer even when severe peak interference occurs. The throughput of the SDD-EDS enables high count spectra to be measured that are stable in calibration and resolution (peak shape) across the full deadtime range. With this high spectral stability, multiple linear least squares peak fitting is successful for separating overlapping peaks and spectral background. Careful specimen preparation is necessary to remove topography on unknowns and standards. The standards-based matrix correction procedure embedded in the NIST DTSA-II software engine returns quantitative results supported by a complete error budget, including estimates of the uncertainties from measurement statistics and from the physical basis of the matrix corrections. NIST DTSA-II is 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.

2014-09-01

104

EDAX Compact Detector Unit EDAX detector is used for advanced materials characterization of energy dispersive X-ray microanalysis (EDS).  

E-print Network

EDAX Compact Detector Unit EDAX© detector is used for advanced materials characterization of energy dispersive X-ray microanalysis (EDS). In 1992, EDAX introduced the Compact Detector Unit (CDU), a major breakthrough in Si(Li) detecting technology. Based on our successful standard detector, the CDU features

105

Titanium dioxide determination in sunscreen by energy dispersive X-ray fluorescence methodology.  

PubMed

Nowadays there are many sun-protection cosmetics incorporating chemical and/or physical UV filters as active ingredients and there are no official methods to determine these kinds of compounds in sunscreen cosmetics. The objective of this work is to estimate TiO(2) concentration, without sample preparation, employing a portable energy dispersive X-ray fluorescence (EDXRF), aiming to estimate the sun protection factor (SPF) due to the physical barrier in sunscreen composition, and also identify the metals present in the samples. A portable EDXRF system was used for the analysis of fifteen commercial samples. It was also prepared three formulations estimated in FPS-30 using TiO(2) at 5%. Quantification was performed using calibration curves with standards from 1 to 30%. The physical barrier contribution in the SPF, associated to Ti concentration, was determined for all samples. The presence of some elements, like K, Zn, Br and Sr was detected in the sunscreen, identifying chemical elements that were not cited in the formulations. Three commercial samples were analyzed for total SPF determination and the result shows that the measured value is 10% lower than the nominal one. PMID:18395052

Melquiades, F L; Ferreira, D D; Appoloni, C R; Lopes, F; Lonni, A G; Oliveira, F M; Duarte, J C

2008-04-21

106

Polarity characterization by anomalous x-ray dispersion of ZnO films and GaN lateral polar structures  

NASA Astrophysics Data System (ADS)

We demonstrate the use of anomalous x-ray scattering of constituent cations at their absorption edge, in a conventional Bragg-Brentano diffractometer, to measure absolutely and quantitatively the polar orientation and polarity fraction of unipolar and mixed polar wurtzitic crystals. In one set of experiments, the gradual transition between c+ and c- polarity of epitaxial ZnO films on sapphire as a function of MgO buffer layer thickness is monitored quantitatively, while in a second experiment, we map the polarity of a lateral polar homojunction in GaN. The dispersion measurements are compared with piezoforce microscopy images, and we demonstrate how x-ray dispersion and scanning probe methods can provide complementary information that can discriminate between polarity fractions at a material surface and polarity fractions averaged over the film bulk.

Shelton, Christopher T.; Sachet, Edward; Paisley, Elizabeth A.; Hoffmann, Marc P.; Rajan, Joseph; Collazo, Ramón; Sitar, Zlatko; Maria, Jon-Paul

2014-01-01

107

Scanning electron microscopy and energy-dispersive x-ray spectroscopy analysis of submicrometer coal fly ash particles  

Microsoft Academic Search

Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) were used to analyze two groups of submicrometer coal fly ash particles from eastern and western power plants. The composition of the particles was related to the composition of the regional coal used. No sulfur was detected in the ash from the plant using low-sulfur western coal. The power plant using

David Lichtman; Susan Mroczkowski

1985-01-01

108

Detection of chlorine-labelled chitosan in Scots pine by energy-dispersive X-ray spectroscopy  

Microsoft Academic Search

The aim of this study was to use energy-dispersive X-ray spectroscopy (EDX) to localize chitosan in the cell wall of chitosan-impregnated\\u000a Scots pine. It was of interest to investigate the concentration of chitosan in wood to gain further knowledge and understanding\\u000a of the distribution of chitosan in the wooden matrix. After deacetylation, chitosan was re-acetylated with chloroacetic anhydride\\u000a to achieve

Erik Larnøy; Morten Eikenes; Holger Militz

2011-01-01

109

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

110

Near-surface density profiling of Fe ion irradiated Si (100) using extremely asymmetric x-ray diffraction by variation of the wavelength  

NASA Astrophysics Data System (ADS)

In this work, we report on correlations between surface density variations and ion parameters during ion beam-induced surface patterning process. The near-surface density variations of irradiated Si(100) surfaces were investigated after off-normal irradiation with 5 keV Fe ions at different fluences. In order to reduce the x-ray probing depth to a thickness below 5 nm, the extremely asymmetrical x-ray diffraction by variation of wavelength was applied, exploiting x-ray refraction at the air-sample interface. Depth profiling was achieved by measuring x-ray rocking curves as function of varying wavelengths providing incidence angles down to 0°. The density variation was extracted from the deviations from kinematical Bragg angle at grazing incidence angles due to refraction of the x-ray beam at the air-sample interface. The simulations based on the dynamical theory of x-ray diffraction revealed that while a net near-surface density decreases with increasing ion fluence which is accompanied by surface patterning, there is a certain threshold of ion fluence to surface density modulation. Our finding suggests that the surface density variation can be relevant with the mechanism of pattern formation.

Khanbabaee, B.; Facsko, S.; Doyle, S.; Pietsch, U.

2014-10-01

111

Time-resolved X-ray diffraction investigation of the modified phonon dispersion in InSb nanowires.  

PubMed

The modified phonon dispersion is of importance for understanding the origin of the reduced heat conductivity in nanowires. We have measured the phonon dispersion for 50 nm diameter InSb (111) nanowires using time-resolved X-ray diffraction. By comparing the sound speed of the bulk (3880 m/s) and that of a classical thin rod (3600 m/s) to our measurement (2880 m/s), we conclude that the origin of the reduced sound speed and thereby to the reduced heat conductivity is that the C44 elastic constant is reduced by 35% compared to the bulk material. PMID:24387246

Jurgilaitis, A; Enquist, H; Andreasson, B P; Persson, A I H; Borg, B M; Caroff, P; Dick, K A; Harb, M; Linke, H; Nüske, R; Wernersson, L-E; Larsson, J

2014-02-12

112

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

113

A suite of programs for calculating x-ray absorption, reflection, and diffraction performance for a variety of materials at arbitrary wavelengths  

SciTech Connect

One of the most useful characteristics of synchrotron radiation is the wide spectral distribution of the source. For applications involving tuned monochromatic beams it is often helpful to predict the x-ray optical characteristics of a sample or the beam line optics at a particular wavelength. In contrast to this desire stands the fact that tabulated values for the optical parameters of interest are generally available only at wavelengths corresponding to typical x-ray tube sources. We have developed a suite of FORTRAN programs which calculate photoabsorption cross sections and atomic scattering factors for materials of arbitrary, uniform composition or for arbitrary layered materials. Further, the suite includes programs for calculation of x-ray diffraction or reflection from such materials. These programs are of use for experimental planning, data analysis, and predictions of performance of beam line optical elements.

Brennan, S. (Stanford Synchrotron Radiation Laboratory, Stanford, California 94309 (United States)); Cowan, P.L. (National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States))

1992-01-01

114

DIFFERENCES IN APPARENT INTERSTRATIFICAT ION OF AN ORGANO-MONTMORILLONITE DISPERSED IN VARIOUS ORGANIC SOLVENTS I. X-RAY DIFFRACTION STUDY  

Microsoft Academic Search

The degree and tlpe of interstratification of a dimethyldioctadeclamine montmorillonite after dispersion in various organic solvents were studied by X-ray diffraction methods. Diffraction data from oriented films of the specimens were obtained at temperatures of 35\\

Janos L. McArnn

115

The Chandra Multi-wavelength Project: Optical Spectroscopy and the Broadband Spectral Energy Distributions of X-ray selected AGNs  

NASA Astrophysics Data System (ADS)

From optical spectroscopy of X-ray serendipitous sources observed as part of ChaMP, we present redshifts and classifications for a total of 1569 Chandra sources from our targeted spectroscopic follow up. We have compiled extensive photometry from X-ray to radio bands. Together with our spectroscopic information, this enables us to derive detailed SEDs for our extragalactic sources. While ~58% of X-ray Seyferts require a starburst event to fit observed photometry only 26% of the X-ray QSO population appear to have some kind of star formation contribution. 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 spectroscopic compilation also allows us to report here the identification of the largest high-redshift X-ray selected sample a total of 78 z>3 sources.

Trichas, Markos; Green, P.; Silverman, J.; Aldcroft, T.; Wilkes, B.; Constantin, A.; Haggard, D.; Kim, DW

2012-09-01

116

X-ray monochromator  

NASA Technical Reports Server (NTRS)

An x-ray monochromator is described, wherin a housing supports a plurality of mirrors forming a plurality of opposed mirror faces in parallel with each other and having thereon multilayer coatings, with each of said pairs of mirror faces being provided with identical coatings which are different from the coatings on the other pairs of mirror faces such that each pair of mirror faces has a peak x-ray reflection at a different wavelength regime. The housing is moveable to bring into a polychromatic x-ray beam that pair of mirror faces having the best x-ray reflection for the desired wavelength, with the mirrors being pivotable to move the mirror faces to that angle of incidence at which the peak reflectivity of the desired wavelength x-rays occurs.

Hoover, Richard B. (inventor)

1992-01-01

117

Improvements in energy dispersive X-ray fluorescence detection limits with thin specimens deposited on thin transparent adhesive tape supports  

NASA Astrophysics Data System (ADS)

The elemental detection limits observed in total reflection X-ray fluorescence analysis (TXRF) are better compared to that of energy dispersive X-ray fluorescence (EDXRF) by approximately three orders of magnitude (in pg level) mainly due to efficient excitation geometry and special features of total reflection of X-rays. Also, the matrix effects are negligible and the thin film approximation is valid for all types of specimens. The detection limits in EDXRF can be improved using thin specimens deposited on thin sample supports so that scattering and thereby background are reduced. In the present study, the detection limits in EDXRF could be improved to ng-pg level for different elements using thin specimens of the samples deposited on thin transparent adhesive tape supports. The EDXRF analytical results were in very good agreement with those of TXRF. The EDXRF detection limit achieved using this approach for Cr was found to be 1050 pg compared to 320 pg obtained in TXRF. For Y these values were found to be 320 and 168 pg respectively. The EDXRF detection limits achieved in the present work have given a new EDXRF analysis methodology for sample analysis with detection limits comparable to TXRF using a simple instrumentation.

Kanrar, Buddhadev; Sanyal, Kaushik; Misra, N. L.; Aggarwal, S. K.

2014-11-01

118

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

119

Evaluating the presence of titanium in XIX-century Brazilian steels by energy-dispersive X-ray fluorescence  

NASA Astrophysics Data System (ADS)

Ores, pig iron and steel pieces from the XIX Century ironworks Royal St. John of Ipanema Iron Foundry (Real Fábrica de Ferro São João do Ipanema), in Iperó, Brazil, were analyzed by Energy-Dispersive X-Ray Fluorescence (EDXRF) spectroscopy, with the aim of investigating the presence of deleterious elements as Ti and P in the minerals and in the resulting products. Analytical modifications made in order to improve the detection limits for Ti and P are discussed. Both elements were found in the raw material and in the products, but large differences in chemical composition were found in different samples or regions of samples.

Neiva, Augusto Camara; Pinto, Herbert Prince Favero; Landgraf, Fernando José Gomes

2014-02-01

120

Enhanced quantification for 3D energy dispersive spectrometry: going beyond the limitation of large volume of X-ray emission.  

PubMed

This paper presents a method developed to quantify three-dimensional energy dispersive spectrometry (3D EDS) data with voxel size smaller than the volume from which X-rays are emitted. The influence of the neighboring voxels is corrected by applying recursively a complex quantification, improving thereby the accuracy of the quantification of critically small features. The enhanced quantification method is applied to simulated and measured data. A systematic improvement is obtained compared with classical quantification, proving the concept and the prospect of this method. PMID:24960631

Burdet, Pierre; Hébert, Cécile; Cantoni, Marco

2014-10-01

121

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

122

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

Microsoft Academic Search

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

Hendrix Demers

2008-01-01

123

Multi-Wavelength Coverage of State Transitions in the New Black Hole X-Ray Binary Swift J1910.2-0546  

E-print Network

Understanding how black holes accrete and supply feedback to their environment is one of the outstanding challenges of modern astrophysics. Swift J1910.2-0546 is a candidate black hole low-mass X-ray binary that was discovered in 2012 when it entered an accretion outburst. To investigate the binary configuration and the accretion morphology we monitored the evolution of the outburst for ~3 months at X-ray, UV, optical (B,V,R,I), and near-infrared (J,H,K) wavelengths using Swift and SMARTS. The source evolved from a hard to a soft X-ray spectral state with a relatively cold accretion disk that peaked at ~0.5 keV. A Chandra/HETG spectrum obtained during this soft state did not reveal signatures of an ionized disk wind. Both the low disk temperature and the absence of a detectable wind could indicate that the system is viewed at relatively low inclination. The multi-wavelength light curves revealed two notable features that appear to be related to X-ray state changes. Firstly, a prominent flux decrease was obser...

Degenaar, N; Cackett, E M; Reynolds, M T; Miller, J M; Reis, R C; King, A L; Gultekin, K; Bailyn, C D; Buxton, M M; MacDonald, R K D; Fabian, A C; Fox, D B; Rykoff, E S

2014-01-01

124

Hard X-ray and Hot Electron Production from Intense Laser Irradiation of Wavelength-Scale Droplets  

Microsoft Academic Search

We have examined the production of hard x-rays from the irradiation of 1 mum diameter water droplets with a 35 fs laser at intensity up to 7 x 10^17 W\\/cm^2. We observe substantial x-ray production in the photon energy range above 100 keV and find that the implied hot electron temperatures from these micron scale targets is significantly higher than

T. Ditmire; S. Wilks; J. Zweiback; T. E. Cowan; T. D. Donnelly; M. Rust; I. Weiner; M. Allen; R. A. Smith

2000-01-01

125

Hard x-ray and hot electron production from intense laser irradiation of wavelength-scale particles  

Microsoft Academic Search

We have examined the production of hard x-rays from the irradiation of ?1 µm diameter water droplets with a 35 fs laser at an intensity of up to 7×1017 Wc m?2. We observe substantial x-ray production in the photon energy range above 100 keV and find that the implied hot electron temperatures from these micron- scale targets are significantly higher

T D Donnelly; M Rust; I Weiner; M Allen; R A Smith; C A Steinke; S Wilks; J Zweiback; T Ditmire

2001-01-01

126

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

127

Evidence for core-shell nanoclusters in oxygen dispersion strengthened steels measured using X-ray absorption spectroscopy  

NASA Astrophysics Data System (ADS)

Nanostructured ferritic alloys (NFA) dispersion strengthened by an ultra high density of Y-Ti-O enriched nano-features (NF) exhibit superior creep strength and the potential for high resistance to radiation damage. However, the detailed character of the NF, that precipitate from solid solution during hot consolidation of metallic powders mechanically alloyed with Y2O3, are not well understood. In order to clarify the nature of the NF, X-ray absorption spectroscopy (XAS) technique, including X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) were used to characterize the local structure of the Ti and Y atoms in both NFA powders and consolidated alloys. The powders were characterized in the as-received, as-milled and after annealing milled powders at 850, 1000 and 1150 °C. The consolidated alloys included powders hot isostatic pressed (HIPed) at 1150 °C and commercial vendor alloys, MA957 and J12YWT. The NFA XAS data were compared various Ti and Y-oxide standards. The XANES and EXAFS spectra for the annealed and HIPed powders are similar and show high temperature heat treatments shift the Y and Ti to more oxidized states that are consistent with combinations of Y2Ti2O7 and, especially, TiO. However, the MA957 and J12YWT and annealed-consolidated powder data differ. The commercial vendor alloys results more closely resemble the as-milled powder data and all show that a significant fraction of substitutional Ti remains dissolved in the (BCC) ferrite matrix.

Liu, S.; Odette, G. R.; Segre, C. U.

2014-02-01

128

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

SciTech Connect

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 Degree-Sign grazing incidence angle around 50A wavelength. The multilayer sample has been characterized by measuring reflectivity of CuK{alpha} radiation and soft x-ray radiation around 50A wavelength.

Biswas, A.; Bhattacharyya, D. [Applied Spectroscopy Division, Bhabha Atomic Research Center, Mumbai 400 085 (India)

2012-06-25

129

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

130

Determination of selenium at trace levels in geologic materials by energy-dispersive X-ray fluorescence spectrometry  

USGS Publications Warehouse

Low levels of selenium (0.1-500 ppm) in both organic and inorganic geologic materials can be semiquantitatively measured by isolating Se as a thin film for presentation to an energy-dispersive X-ray fluorescence spectrometer. Suitably pulverized samples are first digested by fusing with a mixture of Na2CO3 and Na2O2. The fusion cake is dissolved in distilled water, buffered with NH4Cl, and filtered to remove Si and the R2O3 group. A carrier solution of Na2TeO4, plus solid KI, hydrazine sulfate and Na2SO3, is added to the filtrate. The solution is then vacuum-filtered through a 0.45-??m pore-size filter disc. The filter, with the thin film of precipitate, is supported between two sheets of Mylar?? film for analysis. Good agreement is shown between data reported in this study and literature values reported by epithermal neutron-activation analysis and spectrofluorimetry. The method can be made quantitative by utilizing a secondary precipitation to assure complete recovery of the Se. The X-ray method offers fast turn-around time and a reasonably high production rate. ?? 1981.

Wahlberg, J.S.

1981-01-01

131

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

132

Structure and dynamics of concentrated dispersions of polystyrene latex spheres in glycerol: static and dynamic x-ray scattering  

PubMed

X-ray photon correlation spectroscopy and small-angle x-ray scattering measurements are applied to characterize the dynamics and structure of concentrated suspensions of charge-stabilized polystyrene latex spheres dispersed in glycerol, for volume fractions between 2.7% and 52%. The static structures of the suspensions show essentially hard-sphere behavior. The short-time dynamics shows good agreement with predictions for the wave-vector-dependent collective diffusion coefficient, which are based on a hard-sphere model [C. W. J. Beenakker and P. Mazur, Physica A 126, 349 (1984)]. However, the intermediate scattering function is found to violate a scaling behavior found previously for a sterically stabilized hard-sphere suspension [P. N. Segre and P. N. Pusey, Phys. Rev. Lett. 77, 771 (1996)]. Our measurements are parametrized in terms of a viscoelastic model for the intermediate scattering function [W. Hess and R. Klein, Adv. Phys. 32, 173 (1983)]. Within this framework, two relaxation modes are predicted to contribute to the decay of the dynamic structure factor, with mode amplitudes depending on both wave vector and volume fraction. Our measurements indicate that, for particle volume fractions smaller than about 0.30, the intermediate scattering function is well described in terms of single-exponential decays, whereas a double-mode structure becomes apparent for more concentrated systems. PMID:11138124

Lumma; Lurio; Borthwick; Falus; Mochrie

2000-12-01

133

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

NASA Astrophysics Data System (ADS)

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

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

2007-06-01

134

Effect of x-ray energy dispersion in digital subtraction imaging at the iodine K-edge--A Monte Carlo study  

SciTech Connect

The effect of the energy dispersion of a quasi-monochromatic x-ray beam on the performance of a dual-energy x-ray imaging system is studied by means of Monte Carlo simulations using MCNPX (Monte Carlo N-Particle eXtended) version 2.6.0. In particular, the case of subtraction imaging at the iodine K-edge, suitable for angiographic imaging application, is investigated. The average energies of the two beams bracketing the iodine K-edge are set to the values of 31.2 and 35.6 keV corresponding to the ones obtained with a compact source based on a conventional x-ray tube and a mosaic crystal monochromator. The energy dispersion of the two beams is varied between 0 and 10 keV of full width at half-maximum (FWHM). The signal and signal-to-noise ratio produced in the simulated images by iodine-filled cavities (simulating patient vessels) drilled in a PMMA phantom are studied as a function of the x-ray energy dispersion. The obtained results show that, for the considered energy separation of 4.4 keV, no dramatic deterioration of the image quality is observed with increasing x-ray energy dispersion up to a FWHM of about 2.35 keV. The case of different beam energies is also investigated by means of fast simulations of the phantom absorption.

Prino, F.; Ceballos, C.; Cabal, A.; Sarnelli, A.; Gambaccini, M.; Ramello, L. [Dipartimento di Fisica Sperimentale dell'Universita di Torino and INFN, Turin (Italy); CEADEN, Havana (Cuba); Azienda Ospedaliera S. Orsola Malpighi, Bologna (Italy); Dipartimento di Fisica dell'Universita di Ferrara and INFN, Ferrara (Italy); Dipartimento di Scienze e Tecnologie Avanzate dell'Universita del Piemonte Orientale and INFN, Alessandria (Italy)

2008-01-15

135

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

PubMed

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. PMID:24034830

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

2014-01-01

136

Energy-dispersive X-ray fluorescence analysis of moss and soil from abandoned mining of Pb-Zn ores.  

PubMed

This research investigates heavy metal pollution around one of the most important mining areas in Turkey, the Sebinkarahisar (Giresun) lead-zinc mining, by means of analyzing moss and soil samples collected in the neighborhood of the copper mining at different distances. Energy dispersive X-ray fluorescence spectrometry (Epsilon 5, PANalytical, Almelo, The Netherlands) is utilized in the experiments. The results have indicated that the both moss and soil samples contain aluminum, vanadium, chromium, manganese, iron, nickel, copper, zinc, arsenic, barium, cerium, tungsten, and lead. The comparison of the heavy metal concentrations with the typical measurements in the world and with the limit values for the human health has revealed the critical heavy metal pollution levels in the region. The possible consequences of these results are briefly discussed from the point of potential hazards to ecology and human health. PMID:24788924

Koz, B

2014-09-01

137

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

138

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

SciTech Connect

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

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

2011-01-01

139

The Chandra Multi-Wavelength Project (ChaMP): A Serendipitous X-Ray Survey Using Chandra Archival Data  

NASA Technical Reports Server (NTRS)

The launch of the Chandra X-ray Observatory in July 2000 opened a new era in X-ray astronomy. Its unprecedented, < 1" spatial resolution and low background is providing views of the X-ray sky 10-100 times fainter than previously possible. We have begun to carry out a serendipitous survey of the X-ray sky using Chandra archival data to flux limits covering the range between those reached by current satellites and those of the small area Chandra deep surveys. We estimate the survey will cover about 8 sq.deg. per year to X-ray fluxes (2-10 keV) in the range 10(exp -13) - 6(exp -16) erg cm2/s and include about 3000 sources per year, roughly two thirds of which are expected to be active galactic nuclei (AGN). Optical imaging of the ChaMP fields is underway at NOAO and SAO telescopes using g',r',z' colors with which we will be able to classify the X-ray sources into object types and, in some cases, estimate their redshifts. We are also planning to obtain optical spectroscopy of a well-defined subset to allow confirmation of classification and redshift determination. All X-ray and optical results and supporting optical data will be place in the ChaMP archive within a year of the completion of our data analysis. Over the five years of Chandra operations, ChaMP will provide both a major resource for Chandra observers and a key research tool for the study of the cosmic X-ray background and the individual source populations which comprise it. ChaMP promises profoundly new science return on a number of key questions at the current frontier of many areas of astronomy including solving the spectral paradox by resolving the CXRB, locating and studying high redshift clusters and so constraining cosmological parameters, defining the true, possibly absorbed, population of quasars and studying coronal emission from late-type stars as their cores become fully convective. The current status and initial results from the ChaMP will be presented.

Wilkes, Belinda; Lavoie, Anthony R. (Technical Monitor)

2000-01-01

140

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-µm-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

141

Characterizing dispersion and fragmentation of fractal, pyrogenic silica nanoagglomerates by small-angle X-ray scattering.  

PubMed

Typical characterization of nanoparticle dispersion and compounding processes by dynamic light scattering (DLS) and TEM lack quantitative information on fractal structure, aggregation number, and specific surface area. In this work a synchrotron ultra-small-angle X-ray scattering (USAXS) investigation on diffusion flame and 'Aerosil' silica powders, as well as on their desagglomeration by high-pressure liquid dispersion (200-1400 bar) is presented. Primary particle size, polydispersity, and specific surface area are measured for powders, stirred-in dispersions, and after high-pressure processing with identical results, showing the in-situ applicability of USAXS. These parameters, as well as the hard aggregate mass fractal dimension, with typically Df = 2.15 representing reaction-limited cluster aggregation, are determined by synthesis process conditions. They are unchanged even at the highest hydrodynamic stresses; thus, neither comminution nor agglomerate restructuring nor re-agglomeration occurs. Fragmentation reflects in decreasing radii of gyration, which are compared to mobility equivalent radii from DLS in agreement with theory. PMID:17371058

Wengeler, R; Wolf, F; Dingenouts, N; Nirschl, H

2007-04-10

142

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

143

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

144

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

145

STUDIES ON PURE ELEMENT INTENSITIES, MASS ABSORPTION COEFFICIENTS AND PARAMETERS (n AND no FOR ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS  

Microsoft Academic Search

Determination of pure element intensities is important in EDS (energy-dispersive X-ray fluorescence analysis) analysis. In a previous paper, we have studied three determination methods of pure element intensities: the pure thick metal foil, oxide, and low concentration methods. The pure element intensities of Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr, Nb, and

Hua Younan

2001-01-01

146

DIBENZYLAMMONIUM AND SODIUM DIBENZYLDITHIOCARBAMATES AS PRECIPITANTS FOR PRECONCENTRATION OF TRACE ELEMENTS IN WATER FOR ANALYSIS BY ENERGY DISPERSIVE X-RAY FLUORESCENCE  

EPA Science Inventory

Precipitation with combined dibenzylammonium dibenzyldithiocarbamate and sodium dibenzyldithiocarbamate at pH 5.0 can be used to separate 22 trace elements from water. Membrane filtration on the precipitate yielded a thin sample, suitable for analysis by energy dispersive X-ray f...

147

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

EPA Science Inventory

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

148

Indirect determination of dissolved silicate in surface water using energy-dispersive X-ray fluorescence spectrometry.  

PubMed

An ultrasound-assisted methodology for the determination of dissolved silicate in water has been developed by combining the miniaturized ion-associated based preconcentration method with energy dispersive X-ray fluorescence spectrometry (EDXRF). The method has been devised for the determination of silicate through molybdenum in the ion-associated complex between 12-molybdosilicate and crystal violet. Because silicate is determined indirectly via molybdenum fluorescent radiation the difficulties resulting from low fluorescence yield and low energy of silicon radiation were successfully overcome. A good ratio of silicon to molybdenum (1 to 41) and a sensitive K? line of molybdenum make possible the determination of low concentration of silicon in the form of dissolved silicate. Under optimized conditions, good linearity, up to 5 ?g of silicon in the form of silicate (r = 0.9990) and a detection limit of 9 ng mL(-1) were achieved. The total RSD for the EDXRF determination of silicate, followed by precipitation of the ion-associated complex and its dissolution in a microdrop of isoamyl alcohol, was 6.5%. The enrichment factor was equal to 142. The developed method was used to determine the dissolved silica content in surface waters. The accuracy and repeatability of the proposed procedure were checked by the standard addition method and compared to the results obtained using the ICP-OES technique. The recovery (in the 93-97% range) was satisfactory and indicated the usefulness of the developed procedure. PMID:24940576

Pytlakowska, Katarzyna; Dabioch, Marzena; Sitko, Rafal

2014-08-21

149

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

150

Chemometric methods for the quantification of crystalline tacrolimus in solid dispersion by powder X-ray diffractrometry.  

PubMed

The objective of this study was to develop powder X-ray diffraction (XRPD) chemometric model for quantifying crystalline tacrolimus from solid dispersion (SD). Three SDs (amorphous tacrolimus component) with varying drug to excipient ratios (24.4%, 6.7%, and 4.3% drug) were prepared. Placebo SDs were mixed with crystalline tacrolimus to make their composition equivalent to three SD (crystalline tacrolimus component). These two components were mixed to cover 0%-100% of crystalline drug. Uniformity of the sample mixtures was confirmed by near-infrared chemical imaging. XRPD showed three distinct peaks of crystalline drug at 8.5°, 10.3°, and 11.2° (2?), which were nonoverlapping with the excipients. Principal component regressions (PCR) and partial least square (PLS) regression used in model development showed high R(2) (>0.99) for all the mixtures. Overall, the model showed low root mean square of standard error, standard error, and bias, which was smaller in PLS than PCR-based model. Furthermore, the model performance was evaluated on the formulations with known percentage of crystalline drug. Model-calculated crystalline drug percentage values were close to actual value. Therefore, these studies strongly suggest the application of chemometric-XRPD models as a quality control tool to quantitatively predict the crystalline drug in the formulation. PMID:24585357

Siddiqui, Akhtar; Rahman, Ziyaur; Bykadi, Srikant; Khan, Mansoor A

2014-09-01

151

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

152

Simultaneous nondestructive analysis of palladium, rhodium, platinum, and gold nanoparticles using energy dispersive X-ray fluorescence.  

PubMed

A selective method is proposed for the determination of palladium, gold, and sulfur in catalytic systems, by direct liquid analysis using energy dispersive X-ray fluorescence (EDXRF), under an atmosphere of helium or air. This method allows a nondestructive analysis of palladium, rhodium, platinum, and gold nanoparticulate catalysts stabilized by imidazolium propane sulfonate based zwitterionic surfactants, allowing the samples to be reused for catalytic studies. The signals from palladium, rhodium, platinum, and gold samples in the presence of imidazolium propane sulfonate-based zwitterionic surfactants obtained using EDXRF before (Pd(2+), Rh(2+), Pt(2+), and Au(3+)) and after (Pd(0), Rh(0), Pt(0), and Au(0)) formation of nanoparticles are essentially identical. The results show that the EDXRF method is nondestructive and allows detection and quantification of the main components of platinum, gold, rhodium, and palladium NPs, including the surfactant concentration, with detection and quantification limits in the range of 0.4-3 mg L(-1). The matrices used in such samples present no problems, even allowing the detection and quantification of interfering elements. PMID:24090428

Fiedler, Haidi D; Drinkel, Emma E; Orzechovicz, Beatriz; Leopoldino, Elder C; Souza, Franciane D; Almerindo, Gizelle I; Perdona, Cristian; Nome, Faruk

2013-11-01

153

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

154

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

PubMed Central

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

2012-01-01

155

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

156

A multi-wavelength view of AB Doradus outer atmosphere . Simultaneous X-ray and optical spectroscopy at high cadence  

NASA Astrophysics Data System (ADS)

Aims: We study the chromosphere and corona of the ultra-fast rotator AB Dor A at high temporal and spectral resolution using simultaneous observations with XMM-Newton in the X-rays, VLT/UVES in the optical, and the ATCA in the radio. Our optical spectra have a resolving power of ~50 000 with a time cadence of ~1 min. Our observations continuously cover more than one rotational period and include both quiescent periods and three flaring events of different strengths. Methods: From the X-ray observations we investigated the variations in coronal temperature, emission measure, densities, and abundance. We interpreted our data in terms of a loop model. From the optical data we characterised the flaring chromospheric material using numerous emission lines that appear in the course of the flares. A detailed analysis of the line shapes and line centres allowed us to infer physical characteristics of the flaring chromosphere and to coarsely localise the flare event on the star. Results: We specifically used the optical high-cadence spectra to demonstrate that both turbulent and Stark broadening are present during the first ten minutes of the first flare. Also, in the first few minutes of this flare, we find short-lived (one to several minutes) emission subcomponents in the H? and Ca ii K lines, which we interpret as flare-connected shocks owing to their high intrinsic velocities. Combining the space-based data with the results of our optical spectroscopy, we derive flare-filling factors. Finally, comparing X-ray, optical broadband, and line emission, we find a correlation for two of the three flaring events, while there is no clear correlation for one event. Also, we do not find any correlation of the radio data to any other observed data. Based on observations collected at the European Southern Observatory, Paranal, Chile, 383.D-1002A and on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and NASA.Full Table 6 and reduced data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/560/A69

Lalitha, S.; Fuhrmeister, B.; Wolter, U.; Schmitt, J. H. M. M.; Engels, D.; Wieringa, M. H.

2013-12-01

157

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

158

Gunshot residue testing in suicides: Part I: Analysis by scanning electron microscopy with energy-dispersive X-ray.  

PubMed

Several different methods can be employed to test for gunshot residue (GSR) on a deceased person's hands, including scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDX) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Each of these techniques has been extensively studied, especially on living individuals. The current studies (Part I and Part II) were designed to compare the use and utility of the different GSR testing techniques in a medical examiner setting. In Part I, the hands of deceased persons who died from undisputed suicidal handgun wounds were tested for GSR by SEM-EDX over a 4-year period. A total of 116 cases were studied and analyzed for caliber of weapon, proximity of wound, and results of GSR testing, including spatial deposition upon the hands. It was found that in only 50% of cases with a known self-inflicted gunshot wound was SEM-EDX positive for at least 1 specific particle for GSR. In 18% of the cases there was a discernible pattern (spatial distribution) of the particles on the hand such that the manner in which the weapon was held could be determined. Since only 50% of cases where the person is known to have fired a weapon immediately prior to death were positive for GSR by SEM-EDX, this test should not be relied upon to determine whether a deceased individual has discharged a firearm. Furthermore, in only 18% of cases was a discernible pattern present indicating how the firearm was held. The low sensitivity, along with the low percentage of cases with a discernible pattern, limits the usefulness of GSR test results by SEM-EDX in differentiating self-inflicted from non-self-inflicted wounds. PMID:17721163

Molina, D Kimberley; Martinez, Michael; Garcia, James; DiMaio, Vincent J M

2007-09-01

159

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

160

Cu2ZnSnS4 thin-film solar cell absorber composition revealed by energy-dispersive and soft x-ray emission spectroscopy  

Microsoft Academic Search

Different Cu2ZnSnS4 (CTZS) thin-film solar cell absorbers have been investigated by bulk-sensitive energy-dispersive spectroscopy (EDS) and surface-near bulk-sensitive soft x-ray emission spectroscopy (XES). While we find a good agreement between the computed Zn\\/Sn composition ratio based on the EDS and XES data, the XES determined Cu\\/(Zn+Sn) composition ratio significantly deviates from that based on EDS measurements for some samples. While

M. Bar; B. Schubert; B. Marsen; T. Unold; R. G. Wilks; H. Schock; S. Pookpanratana; M. Blum; S. Krause; Y. Zhang; C. Heske; W. Yang; L. Weinhardt

2010-01-01

161

A shield for reducing the thermal signal from heating holders during in situ energy-dispersive X-ray spectroscopy analysis.  

PubMed

This article describes a simple shield that can be placed on typical commercial heating holders to reduce the thermal signal during heating to reasonable levels for in situ energy-dispersive X-ray spectroscopy analysis. The improved temperature capability provided by the shield is demonstrated by initial compositional analysis results obtained across a solid-liquid interface on Al-Si-Cu-Mg alloy powder particles. Considerations in the design of and improvement for the shield are discussed. PMID:17637078

Eswaramoorthy, Santhana K; Howe, James M; Phillipp, Fritz

2007-08-01

162

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

163

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

164

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

165

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

166

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

167

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

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

168

Center for X-Ray Optics, 1986  

SciTech Connect

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

Not Available

1987-07-01

169

X-ray astronomy  

Microsoft Academic Search

The birth of X-ray astronomy and the nature of X-radiation are considered, taking into account the high-altitude rocket, orbiting observatories, the discovery of cosmic X-ray sources, X-rays and their place in the electromagnetic spectrum, the interaction of X-rays with matter, and X-ray detectors and spectrometers. X-rays from the sun are discussed along with solar-flare X-rays, X-rays from beyond the solar

J. Leonard Culhane; Peter W. Sanford

1981-01-01

170

Chemometric classification of gunshot residues based on energy dispersive X-ray microanalysis and inductively coupled plasma analysis with mass-spectrometric detection  

NASA Astrophysics Data System (ADS)

A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups: 'gunshot residue characteristic', 'consistent with gunshot residue' and environmental particles, respectively. Potential gunshot residue particles are manually checked and - if necessary - confirmed by the operating forensic scientist. As there are continuing developments on the ammunition market worldwide, it becomes more and more difficult to assign a detected particle to a particular ammunition brand. As well, the differentiation towards environmental particles similar to gunshot residue is getting more complex. To keep external conditions unchanged, gunshot residue particles were collected using a specially designed shooting device for the test shots revealing defined shooting distances between the weapon's muzzle and the target. The data obtained as X-ray spectra of a number of particles (3000 per ammunition brand) were reduced by Fast Fourier Transformation and subjected to a chemometric evaluation by means of regularized discriminant analysis. In addition to the scanning electron microscopy in combination with energy dispersive X-ray microanalysis results, isotope ratio measurements based on inductively coupled plasma analysis with mass-spectrometric detection were carried out to provide a supplementary feature for an even lower risk of misclassification.

Steffen, S.; Otto, M.; Niewoehner, L.; Barth, M.; Bro¿?ek-Mucha, Z.; Biegstraaten, J.; Horváth, R.

2007-09-01

171

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

NASA Astrophysics Data System (ADS)

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

Newbury*, Dale E.

2005-12-01

172

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

173

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. PMID:21335909

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

2011-01-01

174

A correlative approach to segmenting phases and ferrite morphologies in transformation-induced plasticity steel using electron back-scattering diffraction and energy dispersive X-ray spectroscopy.  

PubMed

Using a combination of electron back-scattering diffraction and energy dispersive X-ray spectroscopy data, a segmentation procedure was developed to comprehensively distinguish austenite, martensite, polygonal ferrite, ferrite in granular bainite and bainitic ferrite laths in a thermo-mechanically processed low-Si, high-Al transformation-induced plasticity steel. The efficacy of the ferrite morphologies segmentation procedure was verified by transmission electron microscopy. The variation in carbon content between the ferrite in granular bainite and bainitic ferrite laths was explained on the basis of carbon partitioning during their growth. PMID:25126753

Gazder, Azdiar A; Al-Harbi, Fayez; Spanke, Hendrik Th; Mitchell, David R G; Pereloma, Elena V

2014-12-01

175

Ultrastructural differentiation within the central nervous system between indolamines and catecholamines by energy dispersive X-ray analysis following paraformaldehyde pretreatment  

SciTech Connect

Dense bodies containing high amounts of chrome were localized in the perikarya of substantia nigra and dorsal raphe neurons following the cytochemical reaction of endogenous dopamine and serotonin (respectively) with glutaraldehyde-dichromate (GDC). Energy dispersive X-ray analysis of these bodies revealed chrome levels two to four times higher than those recorded from the cytoplasmic background. Pretreatment with paraformaldehyde blocked the GDC reaction within the dense bodies in the substantia nigra (chrome levels similar to background), while the chrome levels in the dense bodies of the raphe neurons remained elevated. This demonstrates that pretreatment with paraformaldehyde allows selective localization of central nervous system serotonin stores by the GDC technique.

McClung, R.E.; Wood, J.

1983-08-01

176

Tautomerism in liquid 1,2,3-triazole: a combined Energy-Dispersive X-Ray Diffraction, Molecular Dynamics and FTIR study  

E-print Network

In this work, we report a multitechnique (energy-dispersive X-Ray diffraction, computational methods and FT-IR spectroscopy) study of the tautomeric equilibrium of 1,2,3-triazole, one of the few small nitrogen-containing eterocycles liquid at room temperature. The T-2H form (C2v symmetry) is found to be strongly favored in gas and solid phases, whereas the neat liquid gives diffraction patterns that can be interpreted satisfactorily with the structure functions calculated from some molecular dynamics results for both T-2H and T-1H tautomers, although the T-2H form gives a slightly better agreement.

Bellagamba, Marco; Gontrani, Lorenzo; Guidoni, Leonardo; Sadun, Claudia

2013-01-01

177

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

SciTech Connect

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

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

2005-06-20

178

Student X-Ray Fluorescence Experiments  

ERIC Educational Resources Information Center

Describes the experimental arrangement for x-ray analysis of samples which involves the following: the radioisotopic x-ray disk source; a student-built fluorescence chamber; the energy dispersive x-ray detector, linear amplifier and bias supply; and a multichannel pulse height analyzer. (GS)

Fetzer, Homer D.; And Others

1975-01-01

179

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

180

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

SciTech Connect

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

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

2003-01-24

181

Nondestructive characterization of municipal-solid-waste-contaminated surface soil by energy-dispersive X-ray fluorescence and low-Z (atomic number) particle electron probe X-ray microanalysis.  

PubMed

The long-term environmental impact of municipal solid waste (MSW) landfilling is still under investigation due to the lack of detailed characterization studies. A MSW landfill site, popularly known as Dhapa, in the eastern fringe of the metropolis of Kolkata, India, is the subject of present study. A vast area of Dhapa, adjoining the current core MSW dump site and evolving from the raw MSW dumping in the past, is presently used for the cultivation of vegetables. The inorganic chemical characteristics of the MSW-contaminated Dhapa surface soil (covering a 2-km stretch of the area) along with a natural composite (geogenic) soil sample (from a small countryside farm), for comparison, were investigated using two complementary nondestructive analytical techniques, energy-dispersive X-ray fluorescence (EDXRF) for bulk analysis and low-Z (atomic number) particle electron probe X-ray microanalysis (low-Z particle EPMA) for single-particle analysis. The bulk concentrations of K, Rb, and Zr remain almost unchanged in all the soil samples. The Dhapa soil is found to be polluted with heavy metals such as Cu, Zn, and Pb (highly elevated) and Ti, Cr, Mn, Fe, Ni, and Sr (moderately elevated), compared to the natural countryside soil. These high bulk concentration levels of heavy metals were compared with the Ecological Soil Screening Levels for these elements (U.S. Environment Protection Agency) to assess the potential risk on the immediate biotic environment. Low-Z particle EPMA results showed that the aluminosilicate-containing particles were the most abundant, followed by SiO2, CaCO3-containing, and carbonaceous particles in the Dhapa samples, whereas in the countryside sample only aluminosilicate-containing and SiO2 particles were observed. The mineral particles encountered in the countryside sample are solely of geogenic origin, whereas those from the Dhapa samples seem to have evolved from a mixture of raw dumped MSW, urban dust, and other contributing factors such as wind, precipitation, weather patterns, farming, and water logging, resulting in their diverse chemical compositions and the abundant observation of carbonaceous species. Particles containing C and P were more abundant in the Dhapa samples than in the countryside soil sample, suggesting that MSW-contaminated soils are more fertile. However, the levels of particles containing potentially toxic heavy metals such as Cr, Mn, Ni, Cu, Zn, and/or Pb in the Dhapa samples were significant, corroborated by their high bulk concentration levels (EDXRF), causing deep concern for the immediate environment and contamination of the food chain through food crops. PMID:22168094

Gupta, Dhrubajyoti; Ghosh, Rita; Mitra, Ajoy K; Roy, Subinit; Sarkar, Manoranjan; Chowdhury, Subhajit; Bhowmik, Asit; Mukhopadhyay, Ujjal; Maskey, Shila; Ro, Chul-Un

2011-11-01

182

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

183

X-Ray Microdiffraction at Megabar Pressures  

NASA Astrophysics Data System (ADS)

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

Mao, H.

2003-12-01

184

Skull x-ray  

MedlinePLUS

X-ray - head; X-ray - skull; Skull radiography; Head x-ray ... You will be asked to lie on the x-ray table or sit in a chair. Your ... there is little or no discomfort during an x-ray. If there is a head injury , positioning ...

185

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

186

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 ...

187

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

188

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

189

Tokamak x ray diagnostic instrumentation  

SciTech Connect

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

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

1987-01-01

190

LETTER TO THE EDITOR: Hard x-ray and hot electron production from intense laser irradiation of wavelength-scale particles  

Microsoft Academic Search

We have examined the production of hard x-rays from the irradiation of ~1 µm diameter water droplets with a 35 fs laser at an intensity of up to 7×1017 W cm-2. We observe substantial x-ray production in the photon energy range above 100 keV and find that the implied hot electron temperatures from these micron-scale targets are significantly higher than

T. D. Donnelly; M. Rust; I. Weiner; M. Allen; R. A. Smith; C. A. Steinke; S. Wilks; J. Zweiback; T. E. Cowan; T. Ditmire

2001-01-01

191

Alterations of the intracellular water and ion concentrations in brain and liver cells during aging as revealed by energy dispersive X-ray microanalysis of bulk specimens  

SciTech Connect

Age dependence of the intracellular concentrations of monovalent ions (Na+, K+ and Cl-) was examined in 1, 11 and 25-month-old rat brain and liver cells by using energy dispersive X-ray microanalysis. The in vivo concentrations of Na+, K+ and Cl- ions were calculated from two different measurements: The elemental concentrations were measured in freeze-dried tissue pieces, and the intracellular water content was determined by means of a recently developed X-ray microanalytic method, using frozen-hydrated and fractured bulk specimens as well as subsequent freeze-drying. All the single monovalent ion concentrations and consequently, also the total monovalent ion content showed statistically significant increases during aging in brain cortical neurons. A 3-6% loss of the intracellular water content was accompanied by a 25-45% increase of the monovalent ionic strengths by the age of 25 months. A membrane protective OH radical scavenger (centrophenoxine) reversed the dehydration in the nerve cells of old animals, resulting in a decrease of the intracellular ion concentrations. Aging has a less prominent effect on the water and ion contents of the hepatocytes. The degree of water loss of cytoplasm exceeds that of the nuclei in the liver, suggesting that dominantly the translational steps can be involved in the general age altered slowing down of the protein synthetic machinery, predicted by the membrane hypothesis of aging.

Lustyik, G.; Nagy, I.

1985-01-01

192

Spatially resolved energy dispersive x-ray diffraction (EDXRD) as a tool for nondestructively providing phase composition depth profiles on cement and other materials  

SciTech Connect

The presence of sulfates in water or soils surrounding portland cement concrete structures leads to progressive degradation. Spatially resolved energy dispersive diffraction (EDXRD) in combination with computed microtomography ({mu}CT) and mechanical measurements can provide the information needed to understand, in detail, the degradation mechanisms that are associated with sulfate attack and to validate accelerated test methods used to evaluate the sulfate resistance of cements. Highly penetrating, high-energy X-rays from synchrotron sources allow the use of EDXRD to nondestructively determine depth profiles for the crystalline phases in the cement paste specimens several millimeters below the sample surface. These depth profiles, and how they vary with sulfate exposure conditions and duration, can be correlated with mechanical changes and the crack patterns seen in the microtomographs. Spatially resolved EDXRD is in principle useful for phase composition mapping and depth profiling in a wide range of materials where the attenuation of high energy x-rays is not extreme. Suitable materials include many ceramic compositions.

Wilkinson, A.P.; Jupe, A.C.; Kurtis, K.E.; Naik, N.N.; Stock, S.R.; Lee, P.L. (NWU); (GIT)

2005-05-25

193

The classification of secondary colorectal liver cancer in human biopsy samples using angular dispersive x-ray diffraction and multivariate analysis  

NASA Astrophysics Data System (ADS)

The motivation behind this study is to assess whether angular dispersive x-ray diffraction (ADXRD) data, processed using multivariate analysis techniques, can be used for classifying secondary colorectal liver cancer tissue and normal surrounding liver tissue in human liver biopsy samples. The ADXRD profiles from a total of 60 samples of normal liver tissue and colorectal liver metastases were measured using a synchrotron radiation source. The data were analysed for 56 samples using nonlinear peak-fitting software. Four peaks were fitted to all of the ADXRD profiles, and the amplitude, area, amplitude and area ratios for three of the four peaks were calculated and used for the statistical and multivariate analysis. The statistical analysis showed that there are significant differences between all the peak-fitting parameters and ratios between the normal and the diseased tissue groups. The technique of soft independent modelling of class analogy (SIMCA) was used to classify normal liver tissue and colorectal liver metastases resulting in 67% of the normal tissue samples and 60% of the secondary colorectal liver tissue samples being classified correctly. This study has shown that the ADXRD data of normal and secondary colorectal liver cancer are statistically different and x-ray diffraction data analysed using multivariate analysis have the potential to be used as a method of tissue classification.

Theodorakou, Chrysoula; Farquharson, Michael J.

2009-08-01

194

Modifications of the X-ray source and monitor at the X-ray Calibration Facility  

NASA Technical Reports Server (NTRS)

In order to test the instruments aboard the Advanced X-ray Astrophysics Facility (AXAF) some modifications will need to be made in the X-ray Calibration Facility at Marshall. Several of these modifications involve the X-ray source and the monitor. The source was redesigned to increase the spectral purity of the beam and decrease its polarization by minimizing the number of bremsstrahlung photons in the beam. This was accomplished by utilizing an annular electron gun which allowed the beam to take off antiparallel to the direction at which electrons are incident on the anode. Two other features of the source are the conical anode which decreases the effective spot size and a rotatable anode and filter wheel which allow the operator to change targets without breaking vacuum. The monitor is an important part of the facility because it is used to determine the X-ray flux at the target. A commercially available solid-state detector, Si(Li), should be used along with appropriate proportional counters for monitoring. This detector will be particularly useful when energy or wavelength dispersive instruments are tested because of its good resolution.

Newbolt, W. Barlow

1986-01-01

195

Simple method of determination of iodide at microgram/L level in potable water with preliminary preconcentration by energy dispersive X-ray fluorescence spectrometry.  

PubMed

A simple method for iodide determination in potable water with preliminary preconcentration has been worked out. Iodide was precipitated as palladium (II) iodide on elemental palladium as a carrier, which was obtained by reduction of Pd(II) with sodium thiosulfate. Ammonium chloropalladite was used as a reagent. The volume of water taken for analysis was between 100 and 500 cm3. The precipitate was filtered through a membrane filter, air-dried and directly analyzed by the energy-dispersive x-ray fluorescence (EDXRF) method. 241Am radioisotope was used as a source of exciting radiation. The precision of the method was 7% for iodide mass per filter equal to 2 micrograms. The detection limit amounted to 0.45 microgram of iodide per filter. PMID:1822324

Holynska, B; Ostachowicz, B; Wegrzynek, D

1991-03-01

196

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

197

A structural and kinetic study by energy dispersion X-ray diffraction: interaction between 1,4-dihydropyridines and biological membranes  

NASA Astrophysics Data System (ADS)

Application of energy dispersive X-ray diffraction to the study of the main transition phase of the pure and doped DMPC ( L?-dimyristoylphosphatidylcholine; 1,2-ditetradecanoyl- sn-glycero-3-phosphatidylcholine) bilayers is reported. The aim is to provide an investigative tool to follow the structural variation induced in these systems by temperature and by insertion of doping substances. Hydrophobic compounds such as 1,4-dihydropyridines are used as doping molecules; Nifedipine and Lacidipine show different physical-chemical properties, modifying in a different way the membrane bilayer and its main transition phase. The results show that this technique is useful for studying these kinds of systems (membrane bilayer or biopolymer), giving information on structural variations that occur in a relatively short time.

Boffi, Federico; Caminiti, Ruggero; Sadun, Claudia; Capuani, Silvia; Giovannelli, Aldo; Congiu Castellano, A.

1998-04-01

198

TOPICAL REVIEW: The energy dispersive x-ray reflectometry as a unique laboratory tool for investigating morphological properties of layered systems and devices  

NASA Astrophysics Data System (ADS)

The principles and technical aspects of the laboratory energy dispersive x-ray reflectometry technique (EDXR) are reviewed. X-ray reflectometry enables us to retrieve information on the morphological parameters (film thickness, surface and interface roughness) of thin films, layered materials and devices at the Å resolution. In the energy dispersive mode it makes use of a polychromatic beam and the energy scan is carried out by means of an energy sensitive detector, allowing us to keep the experimental geometry unchanged during data collection. The advantages offered by the technique, in particular when accurate time-resolved studies are to be performed, are outlined. An overview of the most significant works in the field is also reported, in order to present the wide range of its possible applications. The paper was written taking into account the necessity to provide a comprehensive description of this unusual laboratory technique. The first part of the manuscript is, therefore, devoted to the general aspects of EDXR: theoretical bases, experimental characteristics, advantages and drawbacks in comparison with alternative techniques, instrumental effects that may occur and information that can be gained by its application. In the second part of the paper, we resume the main literature results obtained by applying it to a variety of systems, to show examples of the possibilities it offers. Among the experiments reported, in particular much emphasis is given to the time-resolved in situ ones (for example, devices upon working and systems undergoing morphological modifications), which probably represents the most original use of this method.

Rossi Albertini, V.; Paci, B.; Generosi, A.

2006-12-01

199

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,

200

X-Ray Microscopy  

NASA Astrophysics Data System (ADS)

Preface; Acknowledgements; 1. Introduction; 2. Contact microradiography; 3. Microscopy by point projection; 4. Reflexion x-ray microscopy: mirror systems; 5. Reflexion x-ray microscopy: curved crystals; 6. X-ray absorption microanalysis; 7. X-ray emission microanalysis; 8. Production of x-rays; 9. Specimen preparation techniques; 10. Techniques of contact microradiography; 11. Techniques of projection microscopy; 12. Applications of x-ray microscopy in biology and medicine; 13. Inorganic applications of x-ray microscopy; 14. Microdiffraction; 15. Some new experimental methods; Appendix. Absorption and emission data; References; Index.

Cosslett, V. E.; Nixon, W. C.

2014-06-01

201

Single-shot calibration of soft x-ray mirrors using a sinusoidal transmission gratinga)  

NASA Astrophysics Data System (ADS)

Calibration of soft x-ray diagnostics is a challenge due to the lack of laboratory-size calibrated sources. An in situ calibration method for newly developed x-ray mirrors, is presented. The x-ray source is produced by laser-matter interaction, and twin transmission gratings which create two identical dispersion lines. The gratings have a sinusoidal transmission function, which produces a highly precise high-orders free spectrum. An x-ray mirror interacts with one of the dispersion lines, and the mirror efficiency curve as a function of wavelength is extracted. Mirror efficiency shows good agreement with the literature, and evidence of water layer may justify the need of in situ calibration.

Shpilman, Z.; Ehrlich, Y.; Maman, S.; Levy, I.; Shussman, T.; Oren, G.; Zakosky Nueberger, I.; Hurvitz, G.

2014-11-01

202

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

Microsoft Academic Search

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

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

2002-01-01

203

Four-wave mixing in an optical fiber in the zero-dispersion wavelength region  

Microsoft Academic Search

Fiber four-wave mixing (FWM) in the zero-dispersion wavelength region is described. The phase-matching characteristics are studied in the wavelength region where the first-order chromatic dispersion is zero. The results show that the phase-matching condition is satisfied and FWM light is efficiently generated at particular combinations of input light wavelengths. It is also shown that the deviation of the zero-dispersion wavelength

Kyo Inoue

1992-01-01

204

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

NASA Astrophysics Data System (ADS)

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

Katayama, Tetsuo; Inubushi, Yuichi; Obara, Yuki; Sato, Takahiro; Togashi, Tadashi; Tono, Kensuke; Hatsui, Takaki; Kameshima, Takashi; Bhattacharya, Atanu; Ogi, Yoshihiro; Kurahashi, Naoya; Misawa, Kazuhiko; Suzuki, Toshinori; Yabashi, Makina

2013-09-01

205

Determination of inorganic nutrients in wheat flour by laser-induced breakdown spectroscopy and energy dispersive X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

Laser-induced breakdown spectroscopy (LIBS) and energy dispersive X-ray fluorescence spectrometry (EDXRF) were evaluated for the determination of P, K, Ca, Mg, S, Fe, Cu, Mn and Zn in pressed pellets of wheat flours. EDXRF and LIBS calibration models were built with analytes mass fractions determined by inductively coupled plasma optical emission spectrometry after microwave-assisted acid digestion in a set of 25 wheat flour laboratory samples. Test samples consisted of pressed pellets prepared from wheat flour mixed with 30% mm- 1 cellulose binder. Experiments were carried out with a LIBS setup consisted of a Q-switched Nd:YAG laser and a spectrometer with Echelle optics and ICCD, and a benchtop EDXRF system fitted with a Rh target X-ray tube and a Si(Li) semiconductor detector. The correlation coefficients from the linear calibration models of P, K, Ca, Mg, S, Fe, Mn and Zn determined by LIBS and/or EDXRF varied from 0.9705 for Zn to 0.9990 for Mg by LIBS, and from 0.9306 for S to 0.9974 for K by EDXRF. The coefficients of variation of measurements varied from 1.2 to 20% for LIBS, and from 0.3 to 24% for EDXRF. The predictive capabilities based on RMSEP (root mean square error of prediction) values were appropriate for the determination of P, Ca, Mg, Fe, Mn and Zn by LIBS, and for P, K, S, Ca, Fe, and Zn by EDXRF. In general, results from the analysis of NIST SRM 1567a Wheat flour by LIBS and EDXRF were in agreement with their certified mass fractions.

Peruchi, Lidiane Cristina; Nunes, Lidiane Cristina; de Carvalho, Gabriel Gustinelli Arantes; Guerra, Marcelo Braga Bueno; de Almeida, Eduardo; Rufini, Iolanda Aparecida; Santos, Dário; Krug, Francisco José

2014-10-01

206

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

207

Determination of phosphorus in food samples by X-ray fluorescence spectrometry and standard spectrophotometric method  

Microsoft Academic Search

The Wavelength Dispersive X-ray fluorescence (WD XRF) determination of phosphorus in GMO and non GMO food samples is proposed. The tested materials included commercially available transgenic, unmodified soya-foods and popular dairy products. The WD XRF method was compared with the standard molybdenum blue method. Matrix effects were minimised by using standard reference material. Obtained results were discussed in respect of

A Jastrz?bska; B Brudka; T Szyma?ski; E Sz?yk

2003-01-01

208

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...

209

Two-wavelength moire deflection tomography in studying the dispersive characteristic for flame flow fields  

Microsoft Academic Search

In this paper, the dispersive characteristic of flame flow fields is studied. Two-wavelength moire; deflection tomography is introduced to verify the dispersive characteristic for flame flow field, while 532nm and 808nm are chosen as the probe wavelengths. The combustion of propane in air is chosen as a practical example for theoretical and experimental investigation. The theories manifest that the dispersive

Yun-Yun Chen; Yang Song; An-Zhi He; Zhen-Hua Li

2009-01-01

210

Kinetic Modeling of the X-ray-induced Damage to a Metalloprotein  

PubMed Central

It is well known that biological samples undergo x-ray-induced degradation. One of the fastest occurring x-ray-induced processes involves redox modifications (reduction or oxidation) of redox-active cofactors in proteins. Here we analyze room temperature data on the photoreduction of Mn ions in the oxygen evolving complex (OEC) of photosystem II, one of the most radiation damage sensitive proteins and a key constituent of natural photosynthesis in plants, green algae and cyanobacteria. Time-resolved x-ray emission spectroscopy with wavelength-dispersive detection was used to collect data on the progression of x-ray-induced damage. A kinetic model was developed to fit experimental results, and the rate constant for the reduction of OEC MnIII/IV ions by solvated electrons was determined. From this model, the possible kinetics of x-ray-induced damage at variety of experimental conditions, such as different rates of dose deposition as well as different excitation wavelengths, can be inferred. We observed a trend of increasing dosage threshold prior to the onset of x-ray-induced damage with increasing rates of damage deposition. This trend suggests that experimentation with higher rates of dose deposition is beneficial for measurements of biological samples sensitive to radiation damage, particularly at pink beam and x-ray FEL sources. PMID:23815809

Davis, Katherine M.; Kosheleva, Irina; Henning, Robert W.; Seidler, Gerald T.; Pushkar, Yulia

2013-01-01

211

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

PubMed

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

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

2000-07-01

212

Imaging with x-ray lasers  

SciTech Connect

Collisionally pumped soft x-ray lasers now operate over a wavelength range extending from 35--300 {Angstrom}. These sources have high peak brightness and are now being utilized for x-ray imaging and plasma interferometry. In this paper we will describe our efforts to probe long scalelength plasmas using Moire deflectrometry and soft x-ray imaging. The progress in the development of short pulse x-ray lasers using a double pulse irradiation technique which incorporates a travelling wave pump will also be presented.

Da Silva, L.B.; Cauble, B.; Frieders, G.; Koch, J.A.; MacGowan, B.J.; Matthews, D.L.; Mrowka, S.; Ress, D.; Trebes, J.E.; Weiland, T.L.

1993-11-01

213

X-Ray Telescopes  

NASA Astrophysics Data System (ADS)

X-ray telescopes produce images of x-ray-emitting objects within the telescope's FIELD OF VIEW by reflection from precisely shaped mirrors. Hans Wolter's design in the early 1950s of an x-ray microscope using reflective optics led Riccardo GIACCONI to suggest an `inverted' set of optics, not subject to the fabrication limitations of the microscope, could be used as a cosmic x-ray telescope. As de...

Reid, P.; Murdin, P.

2000-11-01

214

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, ...

215

Hand x-ray  

MedlinePLUS

X-ray - hand ... A hand x-ray is taken in a hospital radiology department or your health care provider's office by an ... technician. You will be asked to place your hand on the x-ray table, and keep it ...

216

Effects of Er:YAG laser irradiation and manipulation treatments on dentin components, part 2: energy-dispersive X-ray fluorescence spectrometry study  

NASA Astrophysics Data System (ADS)

The effects of laser etching, decontamination, and storage treatments on dentin components were studied by energy-dispersive X-ray fluorescence spectrometry (EDXRF). Thirty bovine incisors were prepared to expose the dentin surface and then divided into two main groups based upon the decontamination process and storage procedure: autoclaved (group A, n=15) or stored in aqueous thymol solution (group B, n=15). The surfaces of the dentin slices were schematically divided into four areas, with each one corresponding to a treatment subgroup. The specimens were either etched with phosphoric acid (control subgroup) or irradiated with erbium-doped yttrium-aluminum-garnet (Er:YAG) laser (subgroups: I-80 mJ, II-120 mJ, and III-180 mJ). Samples were analyzed by micro-EDXRF, yielding three spectra for each area (before and after treatment). Surface mappings covering an area of 80×60 points with steps of 20 ?m were also performed on selected specimens. The amount of Ca and P in group A specimens decreased significantly (P<0.05) after the acid etching and the Ca/P ratio increased (P<0.001). Er:YAG laser-etching using lower laser energies did not produce significant changes in dentin components. The mapping data support the hypothesis that acid etching on dentin produced a more chemically homogeneous surface and thus a more favorable surface for the diffusion of adhesive monomers.

Silva Soares, Luís Eduardo; Do Espírito Santo, Ana Maria; Brugnera, Aldo; Zanin, Fátima Antônia Aparecida; Martin, Airton Abraha~O.

2009-03-01

217

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

218

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

219

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 ?g mL(-1) (r=0.9990), and good detection limit (6 ng mL(-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

220

Winter and summer characteristics of airborne particles inside emperor Qin's Terra-Cotta Museum, China: a study by scanning electron microscopy-energy dispersive X-ray spectrometry.  

PubMed

Day- and nighttime total suspended particulate matter was collected inside and outside Emperor Qin's Terra-Cotta Museum in winter and summer 2008. The purpose was to characterize the winter and summer differences of indoor airborne particles in two display halls with different architectural and ventilation conditions, namely the Exhibition Hall and Pit No. 1. The morphology and elemental composition of two season samples were investigated using scanning electron microscopy and energy dispersive X-ray spectrometry. It is found that the particle size, particle mass concentration, and particle type were associated with the visitor numbers in the Exhibition Hall and with the natural ventilation in Pit No. 1 in both winter and summer. Evident winter and summer changes in the composition and physicochemical properties of the indoor suspended particulate matters were related to the source emission and the meteorological conditions. Particle mass concentrations in both halls were higher in winter than in summer. In winter, the size of the most abundant particles at the three sites were all between 0.5 and 1.0 microm, whereas in summer the peaks were all located at less than 0.5 microm. The fraction of sulfur-containing particles was 2-7 times higher in winter than in summer. In addition to the potential soiling hazard, the formation and deposition of sulfur-containing particles in winter may lead to the chemical and physical weathering of the surfaces of the terra-cotta statues. PMID:22010376

Hu, Tafeng; Cao, Junji; Ho, Kinfai; An, Zhisheng; Lee, Shuncheng; Chow, Judith C; Watson, John G; Li, Hua

2011-09-01

221

Scanning electron microscopy and energy-dispersive X-ray microanalysis studies of early dental calculus on resin plates exposed to human oral cavities.  

PubMed

Dental calculus formed after 10 days on resin plates, applied to the lingual sides of the mandibular gingival regions in eight human subjects, was investigated by means of scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX). The mineral deposits were mainly divided into three types: A, B, and C. The type A deposits showing an average Ca/P molar ratio of 1.42 were densely packed with fine needle-shaped crystals formed by the intra- and extra-cellular calcification. The type A deposits, probably composed of Ca-deficient apatites and the transitional forms between apatite and octacalcium phosphate (OCP), were observed in all subjects. The type B deposits showing an average Ca/P molar ratio of 0.96 were aggregated with polygonal column, triangular plate-shaped, and rhombohedral crystals. These crystals identified as brushite (CaHPO4-2H2O:dicalcium phosphate dihydrate: DCPD) were found in four subjects. Platelet-shaped crystals of the type C deposits were observed in three subjects. Their Ca/P molar ratio of 1.26 and the crystal shape were similar to those of OCP. Whitlockite crystals were not found although Mg-containing hexagonal disk-like crystals were observed in two subjects. PMID:1462133

Kodaka, T; Ohohara, Y; Debari, K

1992-06-01

222

Demonstration of enhanced iodine K-edge imaging using an energy-dispersive X-ray computed tomography system with a 25 mm/s-scan linear cadmium telluride detector and a single comparator.  

PubMed

An energy-dispersive (ED) X-ray computed tomography (CT) system is useful for carrying out monochromatic imaging. To perform enhanced iodine K-edge CT, we developed an oscillation linear cadmium telluride (CdTe) detector with a scan velocity of 25 mm/s and an energy resolution of 1.2 keV. CT is performed by repeated linear scans and rotations of an object. Penetrating X-ray photons from the object are detected by the CdTe detector, and event signals of X-ray photons are produced using charge-sensitive and shaping amplifiers. The lower photon energy is determined by a comparator device, and the maximum photon energy of 60 keV corresponds to the tube voltage. Rectangular-shaped comparator outputs are counted by a counter card. In the ED-CT, tube voltage and current were 60 kV and 0.30 mA, respectively, and X-ray intensity was 14.8 ?Gy/s at 1.0m from the source at a tube voltage of 60 kV. Demonstration of enhanced iodine K-edge X-ray CT for cancer diagnosis was carried out by selecting photons with energies ranging from 34 to 60 keV. PMID:22364788

Sato, Eiichi; Oda, Yasuyuki; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2012-05-01

223

Measuring of soft x-ray flashes with the x-ray acoustic effect  

Microsoft Academic Search

An x-ray acoustic detector was found to be sensitive to extremely soft x-ray flashes (5 eV–10 keV, T?1 ?s). The total dose of the flash is measured by the x-ray acoustic effect. The absorbed energy induces an acoustical pulse that is registered with a microphone. The microphone signal only depends on the absorbed energy. It is independent of the wavelength

R. Germer

1984-01-01

224

Quick measurement of crystal truncation rod profiles in simultaneous multi-wavelength dispersive mode  

SciTech Connect

To conduct time-resolved measurements in the wide momentum transfer (q = 4{pi} sin{theta}/{lambda}, {theta}: the glancing angle of the x-ray beam, {lambda}: x-ray wavelength) range of interest, we developed a method that can simultaneously measure the whole profile of x-ray diffraction and crystal truncation rod scattering of interest with no need of rotation of the specimen, detector, and monochromator crystal during the measurement. With a curved crystal polychromator (Si 111 diffraction), a horizontally convergent x-ray beam having a one-to-one correlation between wavelength (energy: 16.24-23.0 keV) and direction is produced. The convergent x-ray beam components of different wavelengths are incident on the specimen in a geometry where {theta} is the same for all the x-ray components and are diffracted within corresponding vertical scattering planes by a specimen ([GaAs(12ML)/AlAs(8 ML)]{sub 50} on GaAs(001) substrate) placed at the focal point. Although {theta} is the same for all the directions, q continuously varies because {lambda} changes as a function of direction. The normalized horizontal intensity distribution across the beam, as measured using a two-dimensional pixel array detector downstream of the specimen, represents the reflectivity curve profile both near to and far from the Bragg point. As for the crystal truncation rod scattering around the 002 reflection, the diffraction profile from the Bragg peak down to reflectivity of 1.0 x 10{sup -9} was measured with a sufficient data collection time (1000-2000 s). With data collection times of 100, 10, 1.0, and 0.1 s, profiles down to a reflectivity of {approx}6 x 10{sup -9}, {approx}2 x 10{sup -8}, {approx}8 x 10{sup -8}, and {approx}8 x 10{sup -7} were measured, respectively. To demonstrate the time-resolving capability of the system, reflectivity curves were measured with time resolutions of 1.0 s while rotating the specimen. We have also measured the diffraction profile around the 113 reflection in the non-specular reflection geometry.

Matsushita, T.; Tajiri, H. [Photon Factory, Institute of Material Structure Science, KEK, Tsukuba, Ibaraki (Japan); Takahashi, T.; Shirasawa, T. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba (Japan); Arakawa, E. [Department of Physics, Tokyo Gakugei University, Koganei, Tokyo (Japan); Toyokawa, H. [Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo (Japan)

2011-11-15

225

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

226

Quantitative determination of low-Z elements in single atmospheric particles on boron substrates by automated scanning electron microscopy-energy-dispersive X-ray spectrometry.  

PubMed

Atmospheric aerosols consist of a complex heterogeneous mixture of particles. Single-particle analysis techniques are known to provide unique information on the size-resolved chemical composition of aerosols. A scanning electron microscope (SEM) combined with a thin-window energy-dispersive X-ray (EDX) detector enables the morphological and elemental analysis of single particles down to 0.1 microm with a detection limit of 1-10 wt %, low-Z elements included. To obtain data statistically representative of the air masses sampled, a computer-controlled procedure can be implemented in order to run hundreds of single-particle analyses (typically 1000-2000) automatically in a relatively short period of time (generally 4-8 h, depending on the setup and on the particle loading). However, automated particle analysis by SEM-EDX raises two practical challenges: the accuracy of the particle recognition and the reliability of the quantitative analysis, especially for micrometer-sized particles with low atomic number contents. Since low-Z analysis is hampered by the use of traditional polycarbonate membranes, an alternate choice of substrate is a prerequisite. In this work, boron is being studied as a promising material for particle microanalysis. As EDX is generally said to probe a volume of approximately 1 microm3, geometry effects arise from the finite size of microparticles. These particle geometry effects must be corrected by means of a robust concentration calculation procedure. Conventional quantitative methods developed for bulk samples generate elemental concentrations considerably in error when applied to microparticles. A new methodology for particle microanalysis, combining the use of boron as the substrate material and a reverse Monte Carlo quantitative program, was tested on standard particles ranging from 0.25 to 10 microm. We demonstrate that the quantitative determination of low-Z elements in microparticles is achievable and that highly accurate results can be obtained using the automatic data processing described here compared to conventional methods. PMID:16131082

Choël, Marie; Deboudt, Karine; Osán, János; Flament, Pascal; Van Grieken, René

2005-09-01

227

Orthogonal identification of gunshot residue with complementary detection principles of voltammetry, scanning electron microscopy, and energy-dispersive X-ray spectroscopy: sample, screen, and confirm.  

PubMed

Field-deployable voltammetric screening coupled with complementary laboratory-based analysis to confirm the presence of gunshot residue (GSR) from the hands of a subject who has handled, loaded, or discharged a firearm is described. This protocol implements the orthogonal identification of the presence of GSR utilizing square-wave stripping voltammetry (SWSV) as a rapid screening tool along with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) to confirm the presence of the characteristic morphology and metal composition of GSR particles. This is achieved through the judicious modification of the working electrode of a carbon screen-printed electrode (CSPE) with carbon tape (used in SEM analysis) to fix and retain a sample. A comparison between a subject who has handled and loaded a firearm and a subject who has had no contact with GSR shows the significant variations in voltammetric signals and the presence or absence of GSR-consistent particles and constituent metals. This initial electrochemical screening has no effect on the integrity of the metallic particles, and SEM/EDX analysis conducted prior to and postvoltammetry show no differences in analytical output. The carbon tape is instrumental in retaining the GSR sample after electrochemical analysis, supported by comparison with orthogonal detection at a bare CSPE. This protocol shows great promise as a two-tier detection system for the presence of GSR from the hands of a subject, whereby initial screening can be conducted rapidly onsite by minimally trained operators; confirmation can follow at the same substrate to substantiate the voltammetric results. PMID:25084547

O'Mahony, Aoife M; Samek, Izabela A; Sattayasamitsathit, Sirilak; Wang, Joseph

2014-08-19

228

A Multi-Wavelength, Multi-Epoch Study of the Soft X-Ray Transient Prototype, V616 Mon (A0620-00)  

E-print Network

We have obtained optical and infrared photometry of the soft x-ray transient prototype V616 Mon (A0620-00). From this photometry, we find a spectral type of K4 for the secondary star in the system, which is consistent with spectroscopic observations. We present J-, H-, and K-band light curves modeled with WD98 and ELC. Combining detailed, independently run models for ellipsoidal variations due to a spotted, non-spherical secondary star, and the observed ultraviolet to infrared spectral energy distribution of the system, we show that the most likely value for the orbital inclination is 40.75 +/- 3 deg. This inclination angle implies a primary black hole mass of 11.0 +/- 1.9 solar masses.

Dawn M. Gelino; Thomas E. Harrison; Jerome A. Orosz

2001-08-06

229

X-ray Polarimetry  

NASA Astrophysics Data System (ADS)

1. X-ray polarimetry: historical remarks and other considerations; Part I. Polarimetry Techniques: 2. Scattering polarimetry in high energy astronomy; 3. Photoelectric polarimeters; 4. Bragg crystal polarimeters; 5. X-ray polarimetry with the photon counting pixel detector timepix; 6. HE polarized photon interactions with matter: simulations with geant4; 7. The GPD as a polarimeter: theory and facts; 8. Ideal gas electron multipliers (GEMs) for x-ray polarimeters; 9. Broad-band soft x-ray polarimetry; 10. Feasibility of x-ray photoelectric polarimeters with large field of view; 11. Angular resolution of a photoelectric polarimeter; 12. Development of a Thomson x-ray polarimeter; 13. Hard x / soft gamma ray polarimetry using a Laue lens; Part II. Polarized Emission in X-ray Sources: 14. Probing strong gravity effects with x-ray polarimetry; 15. X-ray polarization from black holes in the thermal state; 16. Strong-gravity effects acting on polarization from orbiting spots; 17. Polarization of thermal emission from accreting black holes; 18. X-ray polarimetry and radio-quiet AGN; 19. The soft x-ray polarization in obscured AGN; 20. The polarization of complex x-ray sources; 21. Polarization of Compton x-rays from jets in AGN; 22. Polarization of x-ray lines from galaxy clusters and elliptical galaxies; 23. Polarization characteristics of rotation-powered pulsars; 24. Polarized x-rays from magnetized neutron stars; 25. Polarization properties of x-ray millisecond pulsars; 26. X-ray polarization signatures of neutron stars; 27. Polarization from the oscillating magnetized accretion torus; 28. X-ray polarization from accreting white dwarfs and associated systems; 29. Polarization of pulsar wind nebulae; 30. X-ray polarization of gamma-ray bursts; 31. Central engine afterglow from GRBs and the polarization signature; 32. GRB afterglow polarimetry. Past, present and future; 33. Gamma-ray polarimetry with SPI; 34. INTEGRAL/IBIS observations of the Crab Nebula and GRB 041219A; 35. Fermi results on the origin of high energy emission in pulsars; 36. Diagnostics of the evolution of spiral galaxies in a cluster environment; Part III. Future Missions: 37. Gravity and extreme magnetism SMEX (GEMS); 38. Programs of x-ray polarimetry in Italy; 39. A polarimeter for IXO; 40. Polarimetry with ASTRO-H soft gamma-ray detector; 41. EXIST and its polarization sensitivity; 42. PoGOLite: a balloon-borne soft gamma-ray polarimeter; 43. Studies of neutron background rejection in the PoGOLite polarimeter; 44. Observing polarized x-rays with PoGOLite; 45. Pre-flight qualification tests of the PoGOLite detector system; 46. The gamma-ray polarimeter experiment (GRAPE) Balloon Payload; 47. POLAR: an instrument dedicated to GRB polarization measurement; 48. Polarisation detection capability of GRIPS; 49. X-ray and y-ray polarimetry small satellite mission polaris; 50. GAP aboard the solar powered sail mission; 51. Hard x-ray polarimeter for small satellite missions; 52. Performance of hard x-ray polarimeter: PHENEX; 53. GRB polarimetry with POET; Index.

Bellazzini, Ronaldo; Costa, Enrico; Matt, Giorgio; Tagliaferri, Gianpiero

2010-07-01

230

Eleven-wavelength switchable fiber ring laser with a dispersion compensation fiber and a delayed interferometer  

Microsoft Academic Search

We demonstrate a fiber ring laser with a dispersion compensation fiber (DCF) and a delayed interferometer (DI) with temperature control, which is able to switch eleven wavelengths one by one. In ring cavity, DCF supplies different effective cavity lengths for different wavelengths, DI generates a wavelength comb corresponding to the ITU grid, a flat-gain erbium-doped fiber amplifier (EDFA) provides uniform

Fei Wang; Xin-Liang Zhang; Jian-Ji Dong; Yu Yu; Zheng Zhang

2008-01-01

231

Chest x-ray  

MedlinePLUS

... ray is an x-ray of the chest, lungs, heart, large arteries, ribs, and diaphragm. ... asthma Bronchiectasis Bronchiolitis Bronchopulmonary dysplasia Byssinosis ... Hypertensive heart disease Hypertrophic cardiomyopathy ...

232

Characterization of acrylic polyamide plastic embolization particles in vitro and in human tissue sections by light microscopy, infrared microspectroscopy and scanning electron microscopy with energy dispersive X-ray analysis  

Microsoft Academic Search

Vascular embolization is a well-established practice for the treatment of tumors and vascular lesions. Rounded beads (microspheres) of various materials (collagen, dextran and trisacryl-polymer-gelatin) were developed to solve problems encountered with earlier versions of embolic material. We performed histochemistry, Fourier transform infrared microspectroscopy and scanning electron microscopy with energy dispersive X-ray analysis on two uterine and one hepatic specimen with

Linda A Murakata; Michael R Lewin-Smith; Charles S Specht; Victor F Kalasinsky; Peter L McEvoy; Tuyethoa N Vinh; Lionel N M I Rabin; Florabel G Mullick

2006-01-01

233

Pulsed laser deposited hard TiC, ZrC, HfC and TaC films on titanium: Hardness and an energy-dispersive X-ray diffraction study  

Microsoft Academic Search

Thin films of TiC, ZrC, HfC and TaC were pulsed laser ablation deposited onto sandblasted pure titanium substrate at a laser beam fluence of 3 J\\/cm2. Deposition temperature was room temperature or 500 °C. The films were investigated by scanning electron microscopy, energy-dispersive X-ray diffraction (EDXD) and hardness measurements. The smooth and compact films of 200 to 600 nm thickness were obtained, consisting

D. Ferro; J. V. Rau; V. Rossi Albertini; A. Generosi; R. Teghil; S. M. Barinov

2008-01-01

234

Selective scavenging of copper, zinc, lead, and arsenic by iron and manganese oxyhydroxide coatings on plankton in lakes polluted with mine and smelter wastes: results of energy dispersive X-ray micro-analysis  

Microsoft Academic Search

Energy dispersive X-ray micro-analyses of the remains of individual organisms in plankton samples, together with more conventional analyses of sediments and water, were performed for the purpose of investigating the accumulation of heavy metals by plankton in three Canadian Shield lakes polluted with Cu, Zn, Cd, Pb, As, and SO2?4 from a base metal mine and smelter. The results showed

Togwell A. Jackson; Thomas Bistricki

1995-01-01

235

Simultaneous determination of parts-per-million level Cr, As, Cd and Pb, and major elements in low level contaminated soils using borate fusion and energy dispersive X-ray fluorescence spectrometry with polarized excitation  

Microsoft Academic Search

Energy-dispersive polarized X-ray fluorescence (ED-P-XRF) spectrometry was evaluated for the analysis of low level contaminated soils for four important contaminant elements (Cr, As, Cd and Pb) and major elements (Fe, Mn, Ti, P, Ca, K, Si, Al, Mg and Na) commonly found in soils. Using a LiBO2 and Li2B4O7 fusion method, synthetic standards were prepared in Al2O3 matrices for trace

Terrance D. Hettipathirana

2004-01-01

236

Analysis of eight argonne premium coal samples by X-ray fluorescence spectrometry  

USGS Publications Warehouse

X-ray fluorescence spectrometric methods were used in the analysis of eight Argonne Premium Coal Samples. Trace elements (Cr, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, La, and Ce) in coal ash were determined by energy-dispersive X-ray fluorescence spectrometry; major elements (Na, Mg, Al, Si, P, S, K, Ca, Ti, Mn, and Fe) in coal ash and trace elements (Cl and P) in whole coal were determined by wavelength-dispersive X-ray fluorescence spectrometry. The results of this study will be used in a geochemical database compiled for these materials from various analytical techniques. The experimental XRF methods and procedures used to determine these major and trace elements are described.

Evans, J.R.; Sellers, G.A.; Johnson, R.G.; Vivit, D.V.; Kent, J.

1990-01-01

237

A von Hamos x-ray spectrometer based on a segmented-type diffraction crystal for single-shot x-ray emission spectroscopy and time-resolved resonant inelastic x-ray scattering studies  

SciTech Connect

We report on the design and performance of a wavelength-dispersive type spectrometer based on the von Hamos geometry. The spectrometer is equipped with a segmented-type crystal for x-ray diffraction and provides an energy resolution in the order of 0.25 eV and 1 eV over an energy range of 8000 eV-9600 eV. The use of a segmented crystal results in a simple and straightforward crystal preparation that allows to preserve the spectrometer resolution and spectrometer efficiency. Application of the spectrometer for time-resolved resonant inelastic x-ray scattering and single-shot x-ray emission spectroscopy is demonstrated.

Szlachetko, J. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Institute of Physics, Jan Kochanowski University, 25-406 Kielce (Poland); Nachtegaal, M.; Boni, E. de; Willimann, M.; Safonova, O.; Sa, J.; Smolentsev, G.; Szlachetko, M.; Bergamaschi, A.; Schmitt, B.; David, C.; Luecke, A. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Bokhoven, J. A. van [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Institute for Chemical and Bioengineering, ETH Zurich, 8093 Zuerich (Switzerland); Dousse, J.-Cl.; Hoszowska, J.; Kayser, Y. [Department of Physics, University of Fribourg, 1700 Fribourg (Switzerland); Jagodzinski, P. [University of Technology, Kielce (Poland)

2012-10-15

238

X-Ray fluorescence analysis in the scanning electron microscope  

Microsoft Academic Search

Summary X-ray fluorescence analysis can be performed in a scanning electron microscope equipped with an energy dispersive X-ray spectrometer by means of a special attachment. For the production of primary X-rays a target is positioned in the electron beam. With this technique an improvement of the detection limits is obtained because of the small fraction of bremsstrahlung in the X-ray

P. Golob

1985-01-01

239

Electromagnetically induced transparency for x-rays.  

SciTech Connect

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s-13s and 1s-13p ({approx}800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 1012 W/cm2. The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.

Buth, C.; Santra, R.; Young, L.; Chemistry

2007-06-22

240

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

241

Electromagnetically Induced Transparency for X Rays  

Microsoft Academic Search

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s-13s and 1s-13p (˜800nm). The minimum laser intensity required to observe electromagnetically induced transparency

Christian Buth; Robin Santra; Linda Young

2007-01-01

242

Electromagnetically Induced Transparency for X Rays  

Microsoft Academic Search

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s⁻¹3s and 1s⁻¹3p (â800 nm). The minimum laser intensity required to observe electromagnetically induced

Christian Buth; Robin Santra; Linda Young

2007-01-01

243

PORTABLE VACUUM X-RAY SPECTROMETER INSTRUMENT FOR ON-SITE ANALYSIS OF AIRBORNE PARTICULATE SULFUR AND OTHER ELEMENTS  

EPA Science Inventory

A portable vacuum wavelength-dispersive x-ray analyzer has been constructed for on-site measurement of the sulfur content of filter-deposited airborne particles. Although designed to analyze for sulfur, the spectrometer is adjustable over a limited range providing the potential f...

244

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

245

Correlation of Microwave and Hard X-Ray Spectral Parameters  

Microsoft Academic Search

We present the analysis of 27 solar flares with multiple peaks that were observed at hard X-ray and microwave wavelengths. A total of 57 simultaneous peaks were observed by BATSE (hard X-rays) and Owens Valley Radio Observatory (microwaves). Throughout the duration of a flare, its spectra at both wavelengths are fitted independently at all times. The hard X-ray spectra were

Adriana V. R. Silva; Haimin Wang; Dale E. Gary

2000-01-01

246

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 ...

247

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 ...

248

Detection of x ray sources in PROS  

NASA Technical Reports Server (NTRS)

The problem of detecting discrete sources in x-ray images has much in common with the problem of automatic source detection at other wavelengths. In all cases, one searches for positive brightness enhancements exceeding a certain threshold, which appear consistent with what one expects for a point source, in the presence of a (possibly) spatially variable background. Multidimensional point spread functions (e.g., dependent on detector position and photon energy) are also common. At the same time, the problem in x-ray astronomy has some unique aspects. For example, for typical x-ray exposures in current or recent observatories, the number of available pixels far exceeds the number of actual x-ray events, so Poisson, rather than Gaussian statistics apply. Further, extended cosmic x-ray sources are common, and one often desires to detect point sources in the vicinity or even within bright, diffuse x-ray emission. Finally, support structures in x-ray detectors often cast sharp shadows in x-ray images making it necessary to detect sources in a region of rapidly varying exposure. We have developed a source detection package within the IRAF/PROS environment which attempts to deal with some of the problems of x-ray source detection. We have patterned our package after the successful Einstein Observatory x-ray source detection programs. However, we have attempted to improve the flexibility and accessibility of the functions and to provide a graphical front-end for the user. Our philosophy has been to use standard IRAF tasks whenever possible for image manipulation and to separate general functions from mission-specific ones. We will report on the current status of the package and discuss future developments, including simulation tasks, to allow the user to assess detection efficiency and source significance, tasks to determine source intensity, and alternative detection algorithms.

Deponte, J.; Primini, F. A.

1992-01-01

249

Opportunities for resonant elastic X-ray scattering at X-ray free-electron lasers  

NASA Astrophysics Data System (ADS)

X-ray Free-Electron Lasers (FELs) are beginning to deliver a revolution in X-ray experiments, thanks to their ultra-bright (peak brightness exceeding 1033 photons/s/mm2/mrad2/0.1%BW), ultrashort (down to a few fs), spatially coherent X-ray pulses. Presently operational facilities cover wide spectral ranges, from the VUV and soft X-ray wavelengths of FLASH in Hamburg (down to 4.2 nm), to the hard X-rays delivered by the LCLS in Stanford (wavelengths of 0.15 nm or shorter). The basic properties of the new sources are briefly reviewed, and the impact on resonant scattering experiments is discussed. The perspective of investigating ultrafast magnetism, and, more generally, the time-dependent response of strongly correlated electron systems, in a pump-and-probe mode at the L edges of 3d transition metals, would be very attractive. In the hard X-ray range, the very recent proposal of self-seeded X-ray FELs, with 10-5 intrinsic bandwidth, tunable wavelength, 100 fs pulses and number of photons per pulse of order 1012 also opens exciting possibilities for resonant scattering.

Altarelli, M.

2012-06-01

250

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

251

Pelvis x-ray  

MedlinePLUS

X-ray - pelvis ... Tumors Degenerative conditions of bones in the hips, pelvis, and upper legs ... hip joint Tumors of the bones of the pelvis Sacroiliitis (inflammation of the area where the sacrum ...

252

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

253

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

254

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

255

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

256

Tunable dispersion using linearly chirped polymer optical fiber Bragg gratings with fixed center wavelength  

Microsoft Academic Search

We propose a new scheme for tunable dispersion using linearly chirped polymer optical fiber Bragg gratings made in fiber tapers. The simple tension and uniform heating to the fiber gratings act as the adjustment and control process. Dispersion is tuned by the applied tensile strain. Owing to the unusually large and negative thermooptic coefficient of polymer fiber, the center wavelength

Hongbo Liu; Huiyong Liu; Gangding Peng; Trevor W. Whitbread

2005-01-01

257

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

258

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

259

Spectra of cosmic X-ray sources  

NASA Technical Reports Server (NTRS)

X-ray measurements provide the most direct probes of astrophysical environments with temperatures exceeding one million K. Progress in experimental research utilizing dispersive techniques (e.g., Bragg and grating spectroscopy) is considerably slower than that in areas utilizing photometric techniques, because of the relative inefficiency of the former for the weak X-ray signals from celestial sources. As a result, the term "spectroscopy" as applied to X-ray astronomy has traditionally satisfied a much less restrictive definition (in terms of resolving power) than it has in other wavebands. Until quite recently, resolving powers of order unity were perfectly respectable, and still provide (in most cases) the most useful spectroscopic data. In the broadest sense, X-ray photometric measurements are spectroscopic, insofar as they represent samples of the overall electromagnetic continua of celestial objects.

Holt, S. S.; Mccray, R.

1982-01-01

260

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

261

X-ray Crystallography  

NSDL National Science Digital Library

In this activity, by the Concord Consortium's Molecular Literacy project, students are introduced to the fundamental principles of X-ray crystallography and "guides students through a series of activities for learning how structural information can be derived from X-ray diffraction patterns." Upon completion of this activity students should be able to describe what can be detected with X-ray crystallography (proteins in particular) and explain the impact of temperature, atom size, and impurities in the test. The activity itself is a java-based interactive resource built upon the free, open source Molecular Workbench software. In the activity, students are allowed to explore at their own pace in a digital environment full of demonstrations, illustrations, and models they can manipulate. In addition to the activity, visitors will find an overview of the activity, a test and rubric, central concepts, and their correlation to AAAS standards.

2008-10-17

262

Crystallization and X-ray Diffraction Analysis of a Novel Immune-Type Receptor from Ictalurus punctatus and Phasing by Selenium Anomalous Dispersion Methods  

SciTech Connect

X-ray diffraction data from crystals of a novel immune-type receptor (NITR10 from the catfish Ictalurus punctatus) were collected to 1.65 Angstroms resolution and reduced to the primitive hexagonal lattice. Native and selenomethionine derivatives of NITR10 crystallized under different conditions yielded P3121 crystals. SeMet NITR10 was phased to a correlation coefficient of 0.77 by SAD methods and experimental electron-density maps were calculated to 1.65 Angstroms . Five NITR10 molecules are predicted to be present in the asymmetric unit based on the Matthews coefficient.

Ostrov,D.; Hernandez Prada, J.; Haire, R.; Cannon, J.; Magis, A.; Bailey, K.; Litman, G.

2007-01-01

263

X-ray microtomography  

SciTech Connect

In this tutorial, we describe X-ray microtomography as a technique to nondestructively characterize material microstructure in three dimensions at a micron level spatial resolution. While commercially available laboratory scale instrumentation is available, we focus our attention on synchrotron-based systems, where we can exploit a high flux, monochromatic X-ray beam to produce high fidelity three-dimensional images. A brief description of the physics and the mathematical analysis behind the technique is followed by example applications to specific materials characterization problems, with a particular focus on the utilization of three-dimensional image processing that can be used to extract a wide range of useful information.

Landis, Eric N., E-mail: landis@maine.edu [Department of Civil and Environmental Engineering, University of Maine, 5711 Boardman Hall, Orono, Maine 04469 (United States); Keane, Denis T., E-mail: dtkeane@northwestern.edu [Department of Materials Science and Engineering, Northwestern University (United States); DND-CAT, Advanced Photon Source, Argonne National Laboratory, Bldg. 432/A002, 9700 S. Cass Ave, Argonne, Illinois 60439 (United States)

2010-12-15

264

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

265

A new method for detecting and localizing cell markers endocytosed by fibroblasts in epoxy resin semi-thin sections using scanning electron microscopy combined with energy dispersive X-ray microanalysis after ion-etching.  

PubMed

Cell marking is widely used to examine cell development and differentiation in developmental biology. We developed a new method for localizing cell markers in a semi-thin epoxy section with scanning electron microscopy. Cultured fibroblasts ingesting carbon particles were autologously transplanted into a rabbit transparent ear chamber, 6 mm in diameter and 100 microm in depth. Eight days after the transplantation, tissues in the chamber were fixed and embedded in epoxy resin. Semi-thin sections were cut and stained with toluidine blue. Fibroblasts in connective tissues which contained black spots were observed with a light microscope. These sections were subsequently ion-etched with an ion-coater and coated with platinum. The same fibroblasts were then visualized by secondary electron imaging using a scanning electron microscope. A nucleus with nuclear envelope, nuclear pores, a nucleolus and heterochromatin, mitochondria with cristae and rough endoplasmic reticulum were observed in the fibroblasts. The black spots in the fibroblasts were identified as bright bodies with the scanning electron microscope. The bright bodies were found to be a lump of tiny particles less than 100 nm in diameter. In order to analyse such particles with energy dispersive X-ray microanalysis, ion-etched sections were coated with carbon. X-ray energy spectrometry clearly demonstrated that these were carbon particles, which had been endocytosed by the fibroblast. This suggests that scanning electron microscopy combined with energy dispersive X-ray microanalysis is useful for detecting carbon particles in the cytoplasm at an ultrastructural level in semi-thin epoxy sections subsequent to ion etching and that this method may be applicable to other cell markers, such as gold particles to track cells in the field of cell development and cell differentiation. PMID:12005195

Fujiwara, T; Shimizu, D; Kon, K; Isshiki, N; Tsunokuni, H; Aoyagi, S

2000-01-01

266

Compton backscattered collmated 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)

2000-01-01

267

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

268

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

269

Proposal for highly residual dispersion compensating defected core decagonal photonic crystal fiber over S+C+L+U wavelength bands  

NASA Astrophysics Data System (ADS)

A defected core decagonal photonic crystal fiber is designed and numerically optimized to obtain its residual chromatic dispersion compensation in the wavelength range of 1460 to 1675 nm i.e., over S+C+L+U wavelength bands having an average dispersion of about -390 ps/(nm km) with a dispersion variation of 7 ps/(nm km). The designed fiber, with a flattened dispersion profile, has four rings of holes in the cladding region, which results in low confinement loss and small effective mode area at wavelength 1550 nm. For residual chromatic dispersion compensation, the proposed fiber can be used in wavelength division multiplexing optical fiber data communication systems.

Islam, Md. Aminul; Ahmad, Redwan; Ali, Md. Sharafat; Nasim, K. M.

2014-07-01

270

Source Scanning Type X-Ray Grating Spectrometer  

Microsoft Academic Search

A method is proposed for designing an x-ray spectrometer which can scan a limited wavelength region without movement of the concave grating or the electronic counter. Spectrometers widely used in the past have consisted of a fixed x-ray source and a movable counter. This method is to use a fixed counter and a scanning x-ray source to avoid undesirable movement

Masao Sawada; Kenjiro Tsutsumi

1969-01-01

271

a Compact Scanning Soft X-Ray Microscope  

Microsoft Academic Search

Soft x-ray microscopes operating at wavelengths between 2.3 nm and 4.4 nm are capable of imaging wet biological cells with a resolution many times that of a visible light microscope. Several such soft x-ray microscopes have been constructed. However, with the exception of contact microscopes, all use synchrotrons as the source of soft x-ray radiation and Fresnel zone plates as

John Anderson Trail

1989-01-01

272

X-ray beam finder  

DOEpatents

An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

Gilbert, H.W.

1983-06-16

273

X-ray astronomical spectroscopy  

NASA Technical Reports Server (NTRS)

The contributions of the Goddard group to the history of X-ray astronomy are numerous and varied. One role that the group has continued to play involves the pursuit of techniques for the measurement and interpretation of the X-ray spectra of cosmic sources. The latest development is the selection of the X-ray microcalorimeter for the Advanced X-ray Astrophysics Facility (AXAF) study payload. This technology is likely to revolutionize the study of cosmic X-ray spectra.

Holt, Stephen S.

1987-01-01

274

X-ray Diffraction  

NSDL National Science Digital Library

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

Langan, Shawn

2012-03-08

275

Soft X-ray imaging of living cells in water: flash contact soft X-ray microscope  

Microsoft Academic Search

Flash contact soft X-ray microscopy (FCSXRM) is an imaging technology for observing living cells in aqueous conditions with a spatial resolution of several tens of nm. The principle of soft X-ray imaging for living cells is carbon imaging, which provides us with a carbon-density-distribution map of the specimens. Carbon and oxygen have absorption edges in the soft X-ray wavelength range

Toshikazu Majima

2004-01-01

276

Nonlinear wavelength conversion in photonic crystal fibers with three zero-dispersion points  

SciTech Connect

In this theoretical study, we show that a simple endlessly single-mode photonic crystal fiber can be designed to yield, not just two, but three zero-dispersion wavelengths. The presence of a third dispersion zero creates a rich phase-matching topology, enabling enhanced control over the spectral locations of the four-wave-mixing and resonant-radiation bands emitted by solitons and short pulses. The greatly enhanced flexibility in the positioning of these bands has applications in wavelength conversion, supercontinuum generation, and pair-photon sources for quantum optics.

Stark, S. P.; Biancalana, F.; Podlipensky, A.; St. J. Russell, P. [Max Planck Institute for the Science of Light Guenther-Scharowsky Str. 1/Bau 24, D-91058 Erlangen (Germany)

2011-02-15

277

Highly efficient pulsed power supply system with a two-stage LC generator and a step-up transformer for fast capillary discharge soft x-ray laser at shorter wavelength.  

PubMed

Highly efficient and compact pulsed power supply system for a capillary discharge soft x-ray laser (SXRL) has been developed. The system consists of a 2.2 microF two-stage LC inversion generator, a 2:54 step-up transformer, a 3 nF water capacitor, and a discharge section with a few tens of centimeter length capillary. Adoption of the pulsed transformer in combination with the LC inversion generator enables us to use only one gap switch in the circuit for charging the water capacitor up to about 0.5 MV. Furthermore, step-up ratio of a water capacitor voltage to a LC inversion generator initial charging voltage is about 40 with energy transfer efficiency of about 50%. It also leads to good reproducibility of a capillary discharge which is necessary for lasing a SXRL stably. For the study of the possibility of lasing a SXRL at shorter wavelength in a small laboratory scale, high-density and high-temperature plasma column suitable for the laser can be generated relatively easily with this system. PMID:20113089

Sakai, Yusuke; Takahashi, Shnsuke; Komatsu, Takanori; Song, Inho; Watanabe, Masato; Hotta, Eiki

2010-01-01

278

Control of Wavelength Dispersion of Birefringence for Oriented Copolycarbonate Films Containing Positive and Negative Birefringent Units  

NASA Astrophysics Data System (ADS)

The wavelength dispersion of birefringence for uniaxially oriented copolycarbonate films containing positive and negative birefringent units has been examined by polarization-modulated transmission spectro-ellipsometry, as a function of copolymerization ratio and stretching parameters. The copolymers were synthesized from 2,2-bis(4-hydroxyphenyl)propane (BPA), 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (BMPF) and phosgene by interfacial polycondensation. The films indicate reverse dispersion in the region of BMPF volume fraction from 0.65 to 0.80. The wavelength dispersion is controlled by the copolymerization ratio. The dispersion change of the 70 mol% BMPF copolycarbonate films as a function of stretching parameters is negligible. These behaviors are explained by the birefringence equation for a multicomponent system of the copolymer.

Uchiyama, Akihiko; Yatabe, Toshiaki

2003-11-01

279

Study of a homogeneous X-ray selected AGN sample  

NASA Astrophysics Data System (ADS)

Based on optical identifications of ROSAT sources, we have created a large homogeneous catalog of X-ray selected AGN. The Hamburg-RASS Catalog (HRC) and Byurakan-Hamburg-RASS Catalog (BHRC) made up on the basis of optical identification of X-ray sources from ROSAT Bright Source (BSC) and Faint Source (FSC) catalogues, respectively, have been used. These identiifcations were based on low-dispersion spectra of Hamburg Quasar Survey (HQS). As a result, a new large sample of X-ray selected AGN has been compiled containing 4253 sources with photon count rate CR > 0.04 ct/s in the area with galactic latitudes |b|>20 and declinations ?>0. All these sources are classified as AGN or candidate AGN. We have carried out multiwavelength studies in several wavelength ranges (X-ray, optical, radio). Catalogues that more or less guarantee the completeness condition (all-sky or large area surveys) were used. A number of erroneous classifications were found (some AGN had been classified as stars or galaxies); 1024 and 59 from HRC and BHRC, respectively. Out of 4253 sources, 3352 are spectroscopically confirmed AGN (given in Veron-Cetty & Veron and Roma Blazar catalogs), and the rest 901 are candidate AGN. For 210 of them spectra are available in SDSS DR9, and the results of their classification are given in another paper. We calculated absolute magnitudes, fluxes, improved coordinates and redshifts. An attempt is made to find a connection between the radiation fluxes in different bands for different types of sources, and identify their typical characteristics, thus confirming candidate AGN and in some cases finding new ones.

Paronyan, Gurgen M.; Mickaelian, Areg M.; Abrahamyan, Hayk V.

2014-07-01

280

Tunable Monochromatic X-ray Source Based on Parametric X-ray Radiation at LEBRA, Nihon University  

NASA Astrophysics Data System (ADS)

The monochromatic X-ray source based on parametric X-ray radiation (PXR) was developed by using the electron beam from the 125-MeV linac at Nihon University. The X-ray generating system consists of two silicon perfect-crystal plates to offer a wide tunability. The system has actually been providing the energy dispersive monochromatic X-ray beam in the region of 6 to 20 keV, using Si(111)-plane for the target and the second crystals. Since the X-ray beam from the PXR generator has rather high energy resolution and coherency, X-ray absorption fine structure (XAFS) measurement and phase-contrast imaging are possible applications of PXR. Actually, preliminary experiments on energy dispersive XAFS measurement and refraction-contrast imaging have been successfully carried out using the PXR beam.

Hayakawa, Y.; Sato, I.; Hayakawa, K.; Tanaka, T.; Kuwada, T.; Sakai, T.; Nogami, K.; Nakao, K.; Inagaki, M.; Mori, A.

2007-01-01

281

X-Ray Second Harmonic Generation  

NASA Astrophysics Data System (ADS)

We report clear experimental evidence for second harmonic generation at hard x-ray wavelengths. Using a 1.7 Å pumping beam generated by a free electron laser, we observe second harmonic generation in diamond. The generated second harmonic is of order 10 times the background radiation, scales quadratically with pump pulse energy, and is generated over a narrow phase-matching condition. Of importance for future experiments, our results indicate that it is possible to observe nonlinear x-ray processes in crystals at pump intensities exceeding 1016 W/cm2.

Shwartz, S.; Fuchs, M.; Hastings, J. B.; Inubushi, Y.; Ishikawa, T.; Katayama, T.; Reis, D. A.; Sato, T.; Tono, K.; Yabashi, M.; Yudovich, S.; Harris, S. E.

2014-04-01

282

Molecular and elemental characterisation of mineral particles by means of parallel micro-Raman spectrometry and Scanning Electron Microscopy/Energy Dispersive X-ray Analysis  

NASA Astrophysics Data System (ADS)

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 can be combined to characterize geological samples, especially in the case of individual particles. The samples involved in the experiments were Zr- and Ti-bearing sand from South Africa (with major minerals such as zircon and rutile) and U mine tailings from Hungary (rich with feldspars, quartz and sulphate minerals). Mineral phases detected by MRS were identified according to their respective main Raman shifts, with a spatial resolution up to 1 ?m, depending on the parameters set. Some unusual and sometimes inexplicable Raman activity was observed, which was ascribed to and rationalized by the presence of accompanying elements as detected with EDX. The relocation of a particle by means of the two instruments was facilitated with TEM grids. Although the limitations of the sequential use of SEM/EDX and MRS, such as different beam sizes, probing depth and surface topography, should be considered in their application to the analysis of individual geological particles, the two methods appeared to be complementary. Not only do they provide correlated chemical information about the sample, but also enable chemical characterization that would be otherwise incomplete when analyzed on a stand-alone basis.

Stefaniak, E. A.; Worobiec, A.; Potgieter-Vermaak, S.; Alsecz, A.; Török, S.; Van Grieken, R.

2006-07-01

283

Holography at x-ray wavelengths  

SciTech Connect

We discuss alternative holographic techniques for imaging microscopic structures with a short-pulse, high intensity, high-quantum-energy laser. We find that Fresnel transform holography using a photoresist for registration of the hologram is most likely to be within the scope of near term technology. Although it has advantages in time gating, using an in-line electron microscope for hologram registration has an unacceptable tradeoff between quantum efficiency and resolution. Fourier transform holography using a reflector to generate the reference beam might be a reasonable alternative using low resolution film, but is necessarily more complicated. We discuss the dependence of the required laser intensity on the resolution sought and on the elastic and absorption cross sections. We conclude that resonant scattering must be used to obtain holograms at reasonable intensities.

Solem, T.C.; Baldwin, G.C.; Chapline, G.F.

1981-01-01

284

X-ray imaging crystal spectrometer for extended X-ray sources  

DOEpatents

Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokomak fusion experiment to provide spatially and temporally resolved data on plasma parameters using the imaging properties for Bragg angles near 45. For a Bragg angle of 45.degree., the spherical crystal focuses a bundle of near parallel X-rays (the cross section of which is determined by the cross section of the crystal) from the plasma to a point on a detector, with parallel rays inclined to the main plain of diffraction focused to different points on the detector. Thus, it is possible to radially image the plasma X-ray emission in different wavelengths simultaneously with a single crystal.

Bitter, Manfred L. (Princeton, NJ); Fraenkel, Ben (Jerusalem, IL); Gorman, James L. (Bordentown, NJ); Hill, Kenneth W. (Lawrenceville, NJ); Roquemore, A. Lane (Cranbury, NJ); Stodiek, Wolfgang (Princeton, NJ); von Goeler, Schweickhard E. (Princeton, NJ)

2001-01-01

285

X-ray Free-electron Lasers  

SciTech Connect

In a free-electron laser (FEL) the lasing medium is a high-energy beam of electrons flying with relativistic speed through a periodic magnetic field. The interaction between the synchrotron radiation that is produced and the electrons in the beam induces a periodic bunching of the electrons, greatly increasing the intensity of radiation produced at a particular wavelength. Depending only on a phase match between the electron energy and the magnetic period, the wavelength of the FEL radiation can be continuously tuned within a wide spectral range. The FEL concept can be adapted to produce radiation wavelengths from millimeters to Angstroms, and can in principle produce hard x-ray beams with unprecedented peak brightness, exceeding that of the brightest synchrotron source by ten orders of magnitude or more. This paper focuses on short-wavelength FELs. It reviews the physics and characteristic properties of single-pass FELs, as well as current technical developments aiming for fully coherent x-ray radiation pulses with pulse durations in the 100 fs to 100 as range. First experimental results at wavelengths around 100 nm and examples of scientific applications planned on the new, emerging x-ray FEL facilities are presented.

Feldhaus, J.; /DESY; Arthur, J.; Hastings, J.B.; /SLAC

2007-02-23

286

X-RAY GROUPS OF GALAXIES IN THE AEGIS DEEP AND WIDE FIELDS  

SciTech Connect

We present the results of a search for extended X-ray sources and their corresponding galaxy groups from 800 ks Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). This yields one of the largest X-ray-selected galaxy group catalogs from a blind survey to date. The red-sequence technique and spectroscopic redshifts allow us to identify 100% of reliable sources, leading to a catalog of 52 galaxy groups. These groups span the redshift range z {approx} 0.066-1.544 and virial mass range M{sub 200} {approx} 1.34 Multiplication-Sign 10{sup 13}-1.33 Multiplication-Sign 10{sup 14} M{sub Sun }. For the 49 extended sources that lie within DEEP2 and DEEP3 Galaxy Redshift Survey coverage, we identify spectroscopic counterparts and determine velocity dispersions. We select member galaxies by applying different cuts along the line of sight or in projected spatial coordinates. A constant cut along the line of sight can cause a large scatter in scaling relations in low-mass or high-mass systems depending on the size of the cut. A velocity-dispersion-based virial radius can cause a larger overestimation of velocity dispersion in comparison to an X-ray-based virial radius for low-mass systems. There is no significant difference between these two radial cuts for more massive systems. Independent of radial cut, an overestimation of velocity dispersion can be created in the case of the existence of significant substructure and compactness in X-ray emission, which mostly occur in low-mass systems. We also present a comparison between X-ray galaxy groups and optical galaxy groups detected using the Voronoi-Delaunay method for DEEP2 data in this field.

Erfanianfar, G.; Lerchster, M.; Nandra, K.; Connelly, J. L.; Mirkazemi, M. [Max Planck-Institute for Extraterrestrial Physics, P.O. Box 1312, Giessenbachstr. 1., D-85741 Garching (Germany); Finoguenov, A. [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, FI-00014 Helsinki (Finland); Tanaka, M. [Institute for the Physics and Mathematics of the Universe, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8583 (Japan); Laird, E. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Bielby, R. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Faber, S. M.; Kocevski, D.; Jeltema, T. [UCO/Lick Observatories, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Cooper, M. [Center for Galaxy Evolution, Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States); Newman, J. A. [Department of Physics and Astronomy, University of Pittsburgh, 401-C Allen Hall, 3941 O'Hara Street, Pittsburgh, PA 15260 (United States); Coil, A. L. [Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Drive, MC 0424, San Diego, CA 92093 (United States); Brimioulle, F. [University Observatory Munich, Ludwigs-Maximilians University Munich, Scheinerstr. 1, D-81679 Munich (Germany); Davis, M. [Department of Astronomy, University of California, Berkeley, Berkeley, CA 94720 (United States); McCracken, H. J. [Institut d'Astrophysique de Paris, UMR 7095 CNRS, Universite Pierre et Marie Curie, 98 bis boulevard Arago, F-75014 Paris (France); Willmer, C. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Gerke, B., E-mail: erfanian@mpe.mpg.de [Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 90R4000, Berkeley, CA 94720 (United States); and others

2013-03-10

287

X-ray lithography masking  

NASA Technical Reports Server (NTRS)

X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

1998-01-01

288

Electromagnetically Induced Transparency for X Rays  

SciTech Connect

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s{sup -1}3s and 1s{sup -1}3p ({approx}800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 10{sup 12} W/cm{sup 2}. The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.

Buth, Christian; Santra, Robin; Young, Linda [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2007-06-22

289

Electromagnetically induced transparency for x rays  

E-print Network

Electromagnetically induced transparency (EIT) is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s^-1 3s and 1s^-1 3p (approximately 800nm). The minimum laser intensity required to observe EIT is of the order of 10^12 W/cm^2. The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.

Buth, Christian; Young, Linda

2007-01-01

290

Electromagnetically induced transparency for x rays.  

PubMed

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s(-1)3s and 1s(-1)3p approximately 800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 10(12) W/cm(2). The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources. PMID:17678019

Buth, Christian; Santra, Robin; Young, Linda

2007-06-22

291

X-ray Dinosaurs  

NSDL National Science Digital Library

In this activity, learners explore dinosaur fossils and skeletons. First, learners listen to "Tyrannosaurus Rex" by Daniel Cohen to learn about T. rex dinosaurs specifically. Then, learners make dinosaur tracings and drawings similar to x-rays. Learners can repeat the activity using pictures of other dinosaurs to compare and contrast various dinosaurs. This activity is featured on page 38 of the "Dinosphere" unit of study for K-2 learners.

Crosslin, Rick; Fortney, Mary; Indianapolis, The C.

2004-01-01

292

Monitoring X-Ray Emission from X-Ray Bursters  

NASA Technical Reports Server (NTRS)

The goal of this investigation was to use the All-Sky Monitor on the Rossi X-Ray Timing Explorer (RXTE) in combination with the Burst and Transient Source Experiment on the Compton Gamma-Ray Observatory to simultaneously measure the x-ray (2-12 keV) and hard x-ray (20-100 keV) emission from x-ray bursters. The investigation was successful. We made the first simultaneous measurement of hard and soft x-ray emission and found a strong anticorrelation of hard and soft x-ray emission from the X-Ray Burster 4U 0614+091. The monitoring performed under this investigation was also important in triggering target of opportunity observations of x-ray bursters made under the investigation hard x-ray emission of x-ray bursters approved for RXTE cycles 1 and 2. These observations lead to a number of papers on high-frequency quasi-periodic oscillations and on hard x-ray emission from the x-ray bursters 4U 0614+091 and 4U 1705-44.

Kaaret, Philip

1998-01-01

293

Grazing-incidence telescopes for X-ray astronomy  

Microsoft Academic Search

We review the progress made at our laboratory over the past several years in developing grazing-incidence imaging X-ray optics. Mirrors, detection systems and dispersion techniques are discussed and experimental results are given. We discuss the application of two telescope systems to a number of experimental observations in X-ray astronomy.

R. Giacconi; W. P. Reidy; G. S. Vaiana; L. P. Van Speybroeck; T. F. Zehnpfennig

1969-01-01

294

Quasi-monochromatic field-emission x-ray source  

SciTech Connect

By favoring the L-peak emission over the bremsstrahlung part, direct quasi-monochromatic soft x-ray emission has been obtained with a field emission (FE) x-ray source. The electron impact x-ray setup uses an arrayed cathode of carbon nanopearl FE tips as a stable cold electron source within a vacuum of 10{sup -6}-10{sup -7} Torr. The high brightness of the FE e-beam coupled with the array structure of the cold cathode allows a smoother control of the x-ray emission intensity. The wavelength of the x-ray source can be modified by the choice of target materials. Using Mo as the target material, the x-ray emission shows a peak centered at 2.45 keV with a monochromaticity between 75% and 55% and a FWHM in the range of 450 eV.

Diop, Babacar; Binh, Vu Thien [LPMCN, University of Lyon 1, Villeurbanne 69622 (France)

2012-09-15

295

Fluctuation X-Ray Scattering  

SciTech Connect

The work supported by the grant was aimed at developing novel methods of finding the structures of biomolecules using x-rays from novel sources such as the x-ray free electron laser and modern synchrotrons

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

2013-01-25

296

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

NASA Astrophysics Data System (ADS)

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

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

2008-09-01

297

Evaluation of micro-energy dispersive X-ray fluorescence and histochemical tests for aluminium detection in plants from High Altitude Rocky Complexes, Southeast Brazil.  

PubMed

The soils developed under High Altitude Rocky Complexes in Brazil are generally of very low chemical fertility, with low base saturation and high exchangeable aluminium concentration. This stressful condition imposes evolutionary pressures that lead to ecological success of plant species that are able to tolerate or accumulate high amounts of aluminium. Several analytical methods are currently available for elemental mapping of biological structures, such as micro-X-ray fluorescence (?-EDX) and histochemical tests. The aim of this study was to combine ?-EDX analysis and histochemical tests to quantify aluminium in plants from High Altitude Rocky Complexes, identifying the main sites for Al-accumulation. Among the studied species, five showed total Al concentration higher than 1000 mg kg-1. The main Al-hyperaccumulator plants, Lavoisiera pectinata, Lycopodium clavatum and Trembleya parviflora presented positive reactions in the histochemical tests using Chrome Azurol and Aluminon. Strong positive correlations were observed between the total Al concentrations and data obtained by ?-EDX analysis. The ?-EDX analysis is a potential tool to map and quantify Al in hyperaccumulator species, and a valuable technique due to its non-destructive capacity. Histochemical tests can be helpful to indicate the accumulation pattern of samples before they are submitted for further ?-EDX scrutiny. PMID:24676168

Campos, Naiara V; Pereira, Tiago A R; Machado, Mariana F; Guerra, Marcelo B B; Tolentino, Gláucia S; Araújo, Josiane S; Rezende, Maíra Q; Silva, Maria Carolina N A da; Schaefer, Carlos E G R

2014-03-01

298

Scanning X-ray microscope  

US Patent & Trademark Office Database

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

1982-02-23

299

Tunable X-ray source  

DOEpatents

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

Boyce, James R. (Williamsburg, VA)

2011-02-08

300

Application of the X-ray fluorescence analysis and X-ray diffraction in geochemical studies of the Pleistocene tills from Holy Cross Mountains  

NASA Astrophysics Data System (ADS)

X-ray fluorescence analysis methods (wavelength dispersive X-ray fluorescence analysis (WDXRF) and total reflection X-ray fluorescence (TXRF)) and X-ray powder diffraction (XRPD) have been applied in complementary geochemical studies of the Pleistocene till samples. The XRPD technique gave information about the mineral composition of the analyzed samples while the WDXRF and TXRF studies allowed the fast elemental analysis. The till samples were collected from different regions of Holy Cross Mountains (located in central Poland) which are still not unambiguously described in the context of the geochemical studies of the Quaternary sediments. The analysis was concentrated on the geochemical composition of the till samples both for materials occurring on the surface (characterized by continuous weathering processes) and for samples taken from core borehole. The overriding purpose of these studies is determination of the local lithotype of the tills and its lithologic and petrographic diagnostic properties, including the chemical composition of clay and minerals found in the clay. In the presented work the experimental sets up, sample preparation procedure and measurements programme will be discussed in details. Finally, the elemental and mineral compositions will be presented for studied different groups of the samples.

Kubala-Kuku?, A.; Ludwikowska-K?dzia, M.; Bana?, D.; Braziewicz, J.; Majewska, U.; Pajek, M.; Wudarczyk-Mo?ko, J.

2013-12-01

301

Energy dispersive X-ray analysis of a Y 2BaCuO 5 grain inside a typical melt-textured growth YBa 2Cu 3O y superconductor  

NASA Astrophysics Data System (ADS)

'Y-deficient phase' has been found around the non-superconducting Y 2BaCuO 5 (Y-211) grains in the melt-textured growth (MTG) YBa 2Cu 3O y (Y-123) superconductor using energy dispersive X-ray analysis (EDX). This result shows that the effective volume of non-Y-123 grain (which might act as magnetic flux pinning centre) should be greater than that of the visible one. According to the MTG crystal growth concept developed recently, the formation of such a 'Y-deficient phase' may be due to the crystallization of unreacted Ba and Cu rich liquids near the boundary of the Y-211 grain during the crystal growth process.

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

1994-06-01

302

Towards attosecond X-ray pulses from the FEL  

SciTech Connect

The ability to study ultrafast phenomena has been recently advanced by the demonstrated production and measurement of a single, 650-attosecond (10{sup 18} sec), VUV x-ray pulse[1] and, latter, a 250-attosecond pulse[2]. The next frontier is a production of the x-ray pulses with shorter wavelengths and in a broader spectral range. Several techniques for a generation of an isolated, attosecond duration, short-wavelength x-ray pulse based upon the ponderomotive laser acceleration [3], SASE and harmonic cascade FELs ([4] - [6]) had been already proposed. In this paper we briefly review a technique proposed in [5] and present some new results.

Zholents, Alexander A.; Fawley, William M.

2004-07-01

303

Jovian X-ray emissions  

NASA Technical Reports Server (NTRS)

The Einstein and Rosat observations of X-ray emissions from Jupiter are summarized. Jupiter's soft X-ray emission is observed to originate from the planet's auroral zones, and specifically, from its equatorial region. The processes responsible for these emissions are not established. The brightness distribution of the Jovian X-rays is characterized by the dependence on central meridian longitude and by north-south and morning-afternoon asymmetries. The X-rays observed during the impact of the comet Shoemaker-Levy 9 are believed to be impact-induced brightenings of the X-ray aurora.

Waite, J. H.; Lewis, W. S.; Gladstone, G. R.; Fabian, A. C.; Brandt, W. N.

1996-01-01

304

X-ray satellite  

NASA Technical Reports Server (NTRS)

An overview of the second quarter 1985 development of the X-ray satellite project is presented. It is shown that the project is proceeding according to plan and that the projected launch date of September 9, 1987 is on schedule. An overview of the work completed and underway on the systems, subsystems, payload, assembly, ground equipment and interfaces is presented. Problem areas shown include cost increases in the area of focal instrumentation, the star sensor light scattering requirements, and postponements in the data transmission subsystems.

1985-01-01

305

Effects of Precursor Composition on the Local Structure of Cu Dispersed on Mesoporous Silica: A Detailed X-ray Absorption Spectroscopy Study  

E-print Network

nanoparticles of ca. 7 Ã? in diameter. After calcination under O2 at 573 K, residual chloride from the high- precipitation.1-4 The support is then dried, and the deposited copper precursor is calcined in air or oxygen the calcination and reduction phases of catalyst preparation.6 Preparation of very highly dispersed Cu catalysts

Bell, Alexis T.

306

SOLITONS: Bright and dark pulses in optical fibres in the vicinity of the zero-dispersion wavelength  

NASA Astrophysics Data System (ADS)

The influence of the third-order dispersion on the propagation of short pulses in optical fibres is considered. The appearance of coupled nonlinear structures consisting of dark and bright envelope solitons is described. The wavelength range is found in the vicinity of the zero-dispersion wavelength where the effect of the third-order dispersion on the pulse propagation proves to be dominant. It is shown that in this case a nonlinear structure in the form of an embedded soliton appears.

Molotkov, I. A.; Bisyarin, M. A.

2004-02-01

307

Development of the water window imaging X-ray microscope utilizing normal-incidence multilayer optics  

NASA Technical Reports Server (NTRS)

A water-window imaging X-ray telescope configured with normal-incidence multilayer X-ray mirrors has been developed to obtain images with unprecedented spatial resolution and contrast of carbon-based microstructures within living cells. The narrow bandpass response inherent in multilayer X-ray optics is accurately tuned to wavelengths within the water window.

Hoover, Richard B.; Shealy, David L.; Brinkley, B. R.; Baker, Phillip C.; Barbee, Troy W., Jr.; Walker, Arthur B. C., Jr.

1991-01-01

308

Hard X-ray emission from X-ray bursters  

Microsoft Academic Search

Hard X-ray emission from compact objects has been considered a spectral signature of black hole candidates. However, SIGMA and BATSE recently detected transient emission in the energy range 30-200keV from several X-ray bursters (XRBs) believed to contain weakly magnetized neutron stars. At least seven XRBs (including Aquila X-1 and 4U 1608-52) are currently known to produce erratic hard X-ray outbursts

M. Tavani; E. Liang

1996-01-01

309

Submicrojoule femtosecond erbium-doped fibre laser for the generation of dispersive waves at submicron wavelengths  

NASA Astrophysics Data System (ADS)

We have demonstrated a femtosecond erbium-doped fibre laser system built in the master oscillator/power amplifier (MOPA) approach. The final amplifier stage utilises a specially designed large mode area active fibre cladding-pumped by multimode laser diodes. The system is capable of generating submicrojoule pulses at a wavelength near 1.6 ?m. We have obtained 530-fs pulses with an energy of 400 nJ. The output of the system can be converted to wavelengths shorter than 1 ?m through the generation of dispersive waves in passive nonlinear fibre. We have obtained ultra-short 7-nJ pulses with a spectral width of ~100 nm and a centre wavelength of 0.9 ?m, which can be used as a seed signal in parametric amplifiers in designing petawatt laser systems.

Kotov, L. V.; Koptev, M. Yu; Anashkina, E. A.; Muravyev, S. V.; Andrianov, A. V.; Bubnov, M. M.; Ignat'ev, A. D.; Lipatov, D. S.; Gur'yanov, A. N.; Likhachev, M. E.; Kim, A. V.

2014-05-01

310

Miniature x-ray source  

DOEpatents

A miniature x-ray source capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature x-ray source comprises a compact vacuum tube assembly containing a cathode, an anode, a high voltage feedthru for delivering high voltage to the anode, a getter for maintaining high vacuum, a connection for an initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is highly x-ray transparent and made, for example, from boron nitride. The compact size and potential for remote operation allows the x-ray source, for example, to be placed adjacent to a material sample undergoing analysis or in proximity to the region to be treated for medical applications.

Trebes, James E. (Livermore, CA); Stone, Gary F. (Livermore, CA); Bell, Perry M. (Tracy, CA); Robinson, Ronald B. (Modesto, CA); Chornenky, Victor I. (Minnetonka, MN)

2002-01-01

311

Iron redistribution in a zirconium alloy after neutron and proton irradiation studied by energy-dispersive X-ray spectroscopy (EDX) using an aberration-corrected (scanning) transmission electron microscope  

NASA Astrophysics Data System (ADS)

Zirconium alloys used as cladding materials in nuclear reactors can exhibit accelerated irradiation induced growth, often termed linear growth, after sustained neutron irradiation. This phenomenon has been linked to the formation of -component dislocation loops and to the concentration of interstitial solute atoms. It is well documented for the Zircaloys that Fe dissolves from second phase particles (SPPs) during irradiation thus increasing the interstitial solute concentration in the matrix. However, no progress has yet been made into understanding whether a similar process occurs for the newer ZIRLO™ alloys. We aim to overcome this shortcoming here by studying compositional changes in second phase particles in Low Tin ZIRLO™ after neutron and proton irradiation using energy dispersive X-ray (EDX) spectroscopy. Material irradiated to 18 dpa (displacements per atom) using neutrons and to 2.3 and 7 dpa by protons was investigated. The results show that Fe is lost from Zr-Nb-Fe-SPPs during both neutron and proton irradiation. Prior to irradiation, Fe was detected at the interface of ?-Nb-SPPs. This Fe enrichment is also dispersed during irradiation. Qualitatively, excellent agreement was found regarding the elemental redistribution processes observed after proton and neutron irradiation.

Francis, E. M.; Harte, A.; Frankel, P.; Haigh, S. J.; Jädernäs, D.; Romero, J.; Hallstadius, L.; Preuss, M.

2014-11-01

312

Characteristics of an ultrafast x-ray streak camera  

SciTech Connect

The detection and temporal dispersion of the x-rays using x-ray streak cameras has been limited to a resolution of 2 ps, primarily due to the transit time dispersion of the electrons between the photocathode and the acceleration grid. The transit time spread of the electrons traveling from the photocathode to the acceleration grid is inversely proportional to the accelerating field. By increasing the field by a factor of 7, we have minimized the effects of transit time dispersion in the photocathode/accelerating grid region and produce an x-ray streak camera with sub-picosecond temporal resolution ({approximately}900 fs). The streak camera has been calibrated using a Michelson interferometer and 100 fs, 400 nm laser light. Time resolved x-ray data is shown from an aluminum target heated at 10{sup 18} W/cm{sup 2} with a 100 fs, 400 nm laser .

Shepherd, R.; Booth, R.; Price, D. [and others

1994-06-01

313

X-ray microscopy of human malaria  

SciTech Connect

Associations between intracellular organisms and host cells are complex and particularly difficult to examine. X-ray microscopy provides transmission images of subcellular structures in intact cells at resolutions superior to available methodologies. The spatial resolution is 50-60nm with a 1 micron depth of focus, superior to anything achievable with light microscopy. Image contrast is generated by differences in photoelectric absorption by the atoms in different areas (i.e. subcellular structures) throughout the full thickness of the sample. Absorption due to carbon dominates among all the elements in the sample at 2.4 nm x-ray wavelength. Thus images show features or structures, in a way not usually seen by other types of microscopy. The authors used soft x-ray microscopy to investigate structural development of Plasmodium falciparum malaria parasites in normal and genetically abnormal erythrocytes, and in infected erythrocytes treated with compounds that have anti-malarial effects. X-ray microscopy showed newly elaborated structures in the cytosol of unstained, intact erythrocytes, redistribution of mass (carbon) in infected erythrocytes, and aberrant parasite morphology. Better understanding of the process of intracellular parasite maturation and the interactions between the parasite and its host erythrocyte can help define new approaches to the control of this deadly disease.

Magowan, C.; Brown, J.T.; Mohandas, N.; Meyer-Ilse, W. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

1997-04-01

314

X-ray holography with atomic resolution  

NASA Astrophysics Data System (ADS)

DIFFRACTION methods for crystallographic structure determination suffer from the so-called 'phase problem'; a diffraction pattern provides intensity but not phase information for the scattered beams, and therefore cannot be uniquely inverted to obtain the crystal structure of a sample. Holographic methods1, on the other hand, offer a means of extracting both intensity and phase information. To be useful for crystallographic applications, holography must be implemented with radiation of sufficiently small wavelength to resolve atomic-scale features2. One method, electron-emission holography3-9, uses electron waves and is a powerful tool for studying surface structure; but it cannot image the internal structure of solids because of complications arising from the highly anisotropic nature of electron scattering processes. A proposed alternative method uses X-rays2,10-13, which scatter more isotropically than electrons. Here we demonstrate the efficacy of atomic-scale X-ray holography by obtaining direct images of the three-dimensional arrangement of strontium atoms in the cubic perovskite SrTiO3. With more intense synchrotron sources for illumination, and with the development of improved X-ray detectors, X-ray holography should become a powerful general technique for unambiguous structure determination in condensed matter systems.

Tegze, Miklós; Faigel, Gyula

1996-03-01

315

Whitebeam X-ray topography  

Microsoft Academic Search

After radiography, white-beam X-ray topography (XRT) is the simplest X-ray imaging technique for crystals. An X-ray topograph is formed by a Bragg reflexion and is in effect a high-spatial-resolution Laue ‘spot’. Synchrotron radiation has given XRT additional powers, with its broad continuous spectrum, small beam divergence, high intensity, strong polarization and regular pulsed time structure. Each Laue image, however, may

Moreton Moore

2012-01-01

316

Synchrotron X-ray topography  

Microsoft Academic Search

The various techniques of X-ray diffraction topography image imperfections in single-crystals by Bragg reflexion, with a spatial resolution of approximately one micrometre. Defects can be studied in relation to crystal growth and physical properties. X-ray interference effects can also be explored in perfect, and nearly perfect, crystals. Synchrotron radiation has given X-ray topography additional powers, including the rapid non-destructive assessment

Moreton Moore

1995-01-01

317

X-Ray Data Booklet  

NSDL National Science Digital Library

The X-Ray Data Booklet is provided by the Center for X-ray Optics and Advanced Light Source of the Lawrence Berkeley National Laboratory, which is funded by the US Department of Energy. The online publication contains topics such as x-ray properties of elements, mass absorption coefficients, synchrotron radiation, scattering processes, low-energy electron ranges in matter, optics and detectors, specular reflectivities for grazing-incidence mirrors, and other practical information that has been produced and gathered as a result of research at the center. Additional features of the informative site include an interactive periodic table of X-Ray properties and free deliverable hardcopies of the document.

Attwood, David.; Gullikson, Eric.; Howells, Malcolm.; Kim, Kwang-Je.; Kirz, Janos.; Kortright, Jeff.

2000-01-01

318

Broadband wavelength-tunable ultrashort pulse source using a Mach-Zehnder modulator and dispersion-flattened dispersion-decreasing fiber.  

PubMed

The broadband wavelength tunability of femtosecond pulse generation using a Mach-Zehnder-modulator-based flat-comb generator (MZ-FCG) and a dispersion-flattened dispersion-decreasing fiber (DF-DDF) was demonstrated. Near-Fourier-transform-limit picosecond pulses generated from the MZ-FCG were compressed into femtosecond pulses by adiabatic soliton compression. By tuning the wavelength of the input cw light, 200 fs, 10 GHz pulses were generated in the wavelength range of 1,535 to 1,570 nm. Such wide-range wavelength tunability was realized by both the independence of a comb-flattening condition from the inputted wavelength and the dispersion flatness of the DF-DDF. PMID:19649076

Morohashi, Isao; Sakamoto, Takahide; Sotobayashi, Hideyuki; Kawanishi, Tetsuya; Hosako, Iwao

2009-08-01

319

The Rossi X-Ray Timing Explorer  

E-print Network

RXTE has been operating for nearly 2 years and is planning the third. The spacecraft performance has been good and the three instruments are operating well. Observations have been made of the range of targets suitable for RXTE, including such different objects as accreting neutron stars and black holes, stellar flares, and supernova remnants. The goals of studying high time resolution and broad energy range and optimizing multi-wavelength participation are yielding important results. Oscillations found from low-mass X-ray binaries probably are signatures of the spin of the neutron stars and of the shortest orbital periods around the neutron stars. These are constraining neutron star parameters. Oscillation and spectral results from black hole candidates bring into the realm of possibility the possibilities of measuring the spins of the black holes and using X-ray data to test predictions of gravitation theory. Multi-wavelength observations are leading to identification of the locations of the X-ray emission regions and, in the case of the micro-quasars, to understanding of the mechanisms for jet formation. Recently faster observing response than originally planned has made possible some RXTE contributions to identification of gamma-ray bursts.

J. H. Swank

1998-02-13

320

Results from a Grazing Incidence X-Ray Interferometer  

NASA Technical Reports Server (NTRS)

A prototype grazing incidence interferometer has been built and tested at EUV and X-ray wavelengths using a 120 meter long vacuum test facility at Marshall Space Flight Center. We describe the design and construction of the interferometer, the EUV and x-ray sources, the detector systems, and compare the interferometric fringe measurements with theoretical predictions. We also describe the next-generation grazing incidence system which is designed to provide laboratory demonstration of key technologies that will be needed for a space-based x-ray interferometer.

Joy, Marshall K.; Shipley, Ann; Cash, Webster; Carter, James

2000-01-01

321

X-Ray Exam: Forearm  

MedlinePLUS

What It Is A forearm X-ray is a safe and painless test that uses a small amount of radiation to take a picture of a person's ... radius, ulna, and elbow). During the examination, an X-ray machine sends a beam of radiation through ...

322

X-ray based extensometry  

NASA Technical Reports Server (NTRS)

A totally new method of extensometry using an X-ray beam was proposed. The intent of the method is to provide a non-contacting technique that is immune to problems associated with density variations in gaseous environments that plague optical methods. X-rays are virtually unrefractable even by solids. The new method utilizes X-ray induced X-ray fluorescence or X-ray induced optical fluorescence of targets that have melting temperatures of over 3000 F. Many different variations of the basic approaches are possible. In the year completed, preliminary experiments were completed which strongly suggest that the method is feasible. The X-ray induced optical fluorescence method appears to be limited to temperatures below roughly 1600 F because of the overwhelming thermal optical radiation. The X-ray induced X-ray fluorescence scheme appears feasible up to very high temperatures. In this system there will be an unknown tradeoff between frequency response, cost, and accuracy. The exact tradeoff can only be estimated. It appears that for thermomechanical tests with cycle times on the order of minutes a very reasonable system may be feasible. The intended applications involve very high temperatures in both materials testing and monitoring component testing. Gas turbine engines, rocket engines, and hypersonic vehicles (NASP) all involve measurement needs that could partially be met by the proposed technology.

Jordan, E. H.; Pease, D. M.

1988-01-01

323

Waveguide delivery of x rays for minimally invasive tumor therapy  

Microsoft Academic Search

We are studying the potential use of x-rays, which are collected by non-imaging optics and delivered through stereotactically guided needles by hollow waveguides, for irradiation of tumors. X-rays have greater transparency in tissue than most longer optical wavelengths and may provide a more uniform dose to a tumor without harming normal tissue. Dosimetry is the key to minimal damage. We

Ronald W. Waynant; Ilko K. Ilev; Kunal Mitra

2001-01-01

324

Filters for soft X-ray solar telescopes  

NASA Technical Reports Server (NTRS)

Soft X-ray telescopes require filters that block visible and infrared light and have good soft X-ray transmission. The optical properties of possible materials are discussed, and the fabrication and testing methods for the filters used in a 10-inch normal incidence telescope for 63 A are described. The best performances in the 44-114-A wavelength range are obtained with foils of carbon and rhodium.

Spiller, Eberhard; Grebe, Kurt; Golub, Leon

1990-01-01

325

X-Ray Bragg Diffraction in Asymmetric Backscattering Geometry  

Microsoft Academic Search

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

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

2006-01-01

326

X-Ray Bragg Diffraction in Asymmetric Backscattering Geometry  

Microsoft Academic Search

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

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

2006-01-01

327

Modeling the X-Ray-Optical Correlations in NGC 3516  

Microsoft Academic Search

We test the ``reprocessing paradigm'' of optical-UV active galactic nucleus (AGN) variability, according to which the variations in this wavelength range are driven by a variable X-ray component, by detailed modeling of the correlated X-ray-optical (3590 and 5510 Å) variability of the recent multiwavelength campaign of NGC 3516. To this end we produce model optical light curves by convolving the

Demosthenes Kazanas; Sergei Nayakshin

2001-01-01

328

X-Ray Interactions with Matter from the Center for X-Ray Optics (CXRO)  

DOE Data Explorer

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

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

329

Nonthermal X-ray astronomy  

NASA Astrophysics Data System (ADS)

We provide a concise review of X-ray observations of synchrotron and inverse Compton radiation from relativistic electrons in cosmic sources, in the context of synergies between X-ray and ?-ray astronomy. Particular emphasis is placed on the cases of supernova remnants, pulsar wind nebulae, and relativistic jets of quasars. We discuss that imaging spectroscopy of synchrotron X-ray emission plays key roles in studying acceleration and transport of high-energy electrons, as well as in probing the magnetic field through a comparison with TeV ?-ray data. To demonstrate some prospects for future X-ray observations, we showcase the scientific capabilities of the next major X-ray observatory, ASTRO-H, which is a joint JAXA-NASA mission to be launched in 2014.

Uchiyama, Yasunobu

2012-12-01

330

X-Ray Diffraction Apparatus  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

331

Focusing X-Ray Telescopes  

NASA Technical Reports Server (NTRS)

During the half-century history of x-ray astronomy, focusing x-ray telescopes, through increased effective area and finer angular resolution, have improved sensitivity by 8 orders of magnitude. Here, we review previous and current x-ray-telescope missions. Next, we describe the planned next-generation x-ray-astronomy facility, the International X-ray Observatory (IXO). We conclude with an overview of a concept for the next next-generation facility, Generation X. Its scientific objectives will require very large areas (about 10,000 sq m) of highly-nested, lightweight grazing-incidence mirrors, with exceptional (about 0.1-arcsec) resolution. Achieving this angular resolution with lightweight mirrors will likely require on-orbit adjustment of alignment and figure.

O'Dell, Stephen; Brissenden, Roger; Davis, William; Elsner, Ronald; Elvis, Martin; Freeman, Mark; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhall; Jerlus, Diab; Juda, Michael; Kolodziejczak, Jeffrey; Murray, Stephen; Petre, Robert; Podgorski, William; Ramsey, Brian; Reid, Paul; Saha, Timo; Wolk, Scott; Troller-McKinstry, Susan; Weisskopf, Martin; Wilke, Rudeger; Zhang, William

2010-01-01

332

Multispectral glancing incidence X-ray telescope  

NASA Technical Reports Server (NTRS)

A multispectral glancing incidence X-ray telescope is illustrated capable of broadband, high-resolution imaging of solar and stellar X-ray and extreme ultraviolet radiation sources which includes a primary optical system preferably of the Wolter I type having a primary mirror system (20, 22). The primary optical system further includes an optical axis (24) having a primary focus (F1) at which the incoming radiation is focused by the primary mirrors. A plurality of ellipsoidal mirrors (30a, 30b, 30cand 30d) are carried at an inclination to the optical axis behind the primary focus (F1). A rotating carrier (32) is provided on which the ellipsoidal mirrors are carried so that a desired one of the ellipsoidal mirrors may be selectively positioned in front of the incoming radiation beam (26). In the preferred embodiment, each of the ellipsoidal mirrors has an identical concave surface carrying a layered synthetic microstructure coating tailored to reflect a desired wavelength of 1.5 .ANG. or longer. Each of the identical ellipsoidal mirrors has a second focus (F2) at which a detector (16) is carried. Thus the different wavelength image is focused upon the detector irregardless of which mirror is positioned in front of the radiation beam. In this manner, a plurality of low wavelengths in a wavelength band generally less than 30 angstroms can be imaged with a high resolution.

Hoover, Richard B. (Inventor)

1990-01-01

333

Radio imaging observations of hard x-ray microflares observed by RHESSI  

NASA Astrophysics Data System (ADS)

We describe the properties of two sets of microflares observed simultaneously by RHESSI (Ramaty High Energy Solar Spectroscopic Imager) in hard X-rays and by two radio imaging instruments--NoRH (Nobeyama Radio Heliograph) in microwaves (17 GHz) and NRH (Nancay Radio Heliograph) at metric wavelengths. The two sets of events occurred in two different time zones, and as a result we do not have simultaneous imaging data in microwaves and metric wavlengths for the same RHESSI events. We'll discuss four events--two observed by NoRH in microwaves and two observed by NRH in meter waves, along with RHESSI events. The microwave (17 GHz) events occurred in AR 9934 at 03:58 UT May 3, 2002 and at 05:08 UT May 4, 2002. We have detected microwave (17 & 34 GHz) emissions in association with RHESSI microflares in the energy range 3-50 keV. The microwave emission comes from footpoints for higher energies, and from the entire mini or small flaring loop for lower energies. The relative positions of microwaves and hard X-rays are as they should be in normal flares. Sometimes the two sources coincide, at other times the two sources are at opposite ends of the flaring loop. One sees the mini flaring loops clearly in NoRH images. RHESSI maps at the time of maximum X-ray emission during the event of May 3, 2002 clearly show an X-ray loop in the range 3-6 keV and two footpoints of the loop in the 6-12 and 12-25 keV ranges. These footpoints are located above opposite magnetic polarities as seen in overlays of hard X-ray images on the MDI images. The MDI magnetograms taken before the microflares show rapid evolution of the magnetic field, including sometimes the emergence of a new region. The hard X-ray spectrum of microwave associated RHESSI microflares can be fit by a thermal component (EM ˜ 3× 1046 cm-3) at low energies (3-6 keV) and a nonthermal component (with slope -3.2) at higher energies. The two metric events imaged by NRH occurred on August 5 and September 3, 2003, one located on the disk and the other at the limb. The RHESSI microflare sources are compact. They are accompanied by a series of metric type III bursts at 150-410 MHz originating from sources located above the RHESSI HXR source. Their source positions show frequency dispersion as expected from plasma radiation sources. The properties of these microflare sources in hard X-rays, microwave and meter wavelengths will be discussed.

Kundu, M.; Trottet, G.; Garaimov, V.; Grigis, P.

334

Stimulated X-ray emission for materials science.  

PubMed

Resonant inelastic X-ray scattering and X-ray emission spectroscopy can be used to probe the energy and dispersion of the elementary low-energy excitations that govern functionality in matter: vibronic, charge, spin and orbital excitations. A key drawback of resonant inelastic X-ray scattering has been the need for high photon densities to compensate for fluorescence yields of less than a per cent for soft X-rays. Sample damage from the dominant non-radiative decays thus limits the materials to which such techniques can be applied and the spectral resolution that can be obtained. A means of improving the yield is therefore highly desirable. Here we demonstrate stimulated X-ray emission for crystalline silicon at photon densities that are easily achievable with free-electron lasers. The stimulated radiative decay of core excited species at the expense of non-radiative processes reduces sample damage and permits narrow-bandwidth detection in the directed beam of stimulated radiation. We deduce how stimulated X-ray emission can be enhanced by several orders of magnitude to provide, with high yield and reduced sample damage, a superior probe for low-energy excitations and their dispersion in matter. This is the first step to bringing nonlinear X-ray physics in the condensed phase from theory to application. PMID:23965622

Beye, M; Schreck, S; Sorgenfrei, F; Trabant, C; Pontius, N; Schüßler-Langeheine, C; Wurth, W; Föhlisch, A

2013-09-12

335

Hard X-Ray Emission of X-Ray Bursters  

NASA Technical Reports Server (NTRS)

The main results from this investigation were serendipitous. The long observation approved for the study of the hard X-ray emission of X-ray bursters lead, instead, to one of the largest early samples of the behavior of fast quasi-periodic oscillations (QPOS) in an atoll sources. Our analysis of this data set lead to the several important discoveries including the existence of a robust correlation between QPO frequency and the flux of a soft blackbody component of the X-ray spectrum in the atoll source 4U 0614+091.

Kaaret, Phillip

1997-01-01

336

Lawrence Livermore National Laboratory Soft X-ray Laser Program: Progress report  

SciTech Connect

Significant progress toward the goal of producing high power, high coherence x-ray lasers has been made. Lasing at wavelengths as low as 66 A has been achieved in a nickel like laser scheme which is scalable to sub-44 A wavelengths. In addition, x-ray laser cavities, x-ray holography, and an applications beamline have been demonstrated. 15 refs., 3 figs.

Trebes, J.; Brown, S.; Campbell, E.M.; Ceglio, N.; Eder, D.; Gaines, D.; Hawryluk, A.; Keane, C.; London, R.; MacGowan, B.

1987-08-01

337

X-Ray Spectroscopy Using Low Temperature Detectors  

NASA Technical Reports Server (NTRS)

After several decades of development, a significant amount of the effort in low temperature detectors (LTDs) is concentrated on deploying real-world experiments. This has resulted from a great deal of basic detector physics performed by several generations of students, post-docs, and researchers. One of the most fruitful applications of LTDs is in non-dispersive x-ray spectroscopy. LTD x-ray spectrometers are broadband, efficient, moderately high-resolution, and can handle moderately high count rates. However, they require significantly more power, mass, and infrastructure compared to traditional solid state x-ray spectrometers, and cannot achieve, at least at low energies, the resolving powers achieved with dispersive spectrometers. In several fields, however, LTDs have or will make a significant contribution. In this review, we will discuss x-ray spectroscopy in general, the fields of science where LTDs are making a significant impact, and some of the current and near-term LTD spectrometers.

Porter, Frederick

2011-01-01

338

P-V-T equation of state of molybdenite (MoS2) by a diamond anvil cell and in situ synchrotron angle-dispersive X-ray diffraction  

NASA Astrophysics Data System (ADS)

The pressure-volume-temperature (P-V-T) equation of state (EoS) of a natural molybdenite (MoS2) has been measured at high temperature up to 700 K and high pressures up to 18.26 GPa, by using in situ angle-dispersive X-ray diffraction and diamond anvil cell. Analysis of room-temperature P-V data to a third-order Birch-Murnaghan EoS yields: V0=107.0±0.1 Å3, K0=67±2 GPa and K?0=5.0±0.3. With K?0 fixed to 4.0, we obtained: V0=106.7±0.1 Å3 and K0=74.5±0.8 GPa. Fitting of our P-V-T data by means of the high-temperature third order Birch-Murnaghan equations of state, gives the thermoelastic parameters: V0=107.0±0.1 Å3, K0=69±2 GPa, K?0=4.7±0.2, (?K/?T)P=-0.021±0.003 GPa K-1, a=(2.2±0.7)×10-5 K-1 and b=(2.9±0.8)×10-8 K-2. The temperature derivative of the bulk modulus and thermal expansion coefficient of MoS2 are obtained for the first time. Present results are also compared with previously studies determined the elastic properties of MoS2 and WS2.

Fan, Dawei; Xu, Jingui; Ma, Maining; Liu, Jing; Xie, Hongsen

2014-10-01

339

Elemental composition of strawberry plants inoculated with the plant growth-promoting bacterium Azospirillum brasilense REC3, assessed with scanning electron microscopy and energy dispersive X-ray analysis.  

PubMed

The elemental composition of strawberry plants (Fragaria ananassa cv. Macarena) inoculated with the plant growth-promoting bacterium Azospirillum brasilense REC3, and non-inoculated controls, was studied using scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analysis. This allowed simultaneous semi-quantification of different elements in a small, solid sample. Plants were inoculated and grown hydroponically in 50% or 100% Hoagland solution, corresponding to limited or optimum nutrient medium, respectively. Bacteria-inoculated plants increased the growth index 45% and 80% compared to controls when grown in 100% and 50% Hoagland solution, respectively. Thus, inoculation with A. brasilense REC3 in a nutrient-limited medium had the strongest effect in terms of increasing both shoot and root biomass and growth index, as already described for Azospirillum inoculated into nutrient-poor soils. SEM-EDS spectra and maps showed the elemental composition and relative distribution of nutrients in strawberry tissues. Leaves contained C, O, N, Na, P, K, Ca and Cu, while roots also had Si and Cl. The organic fraction (C, O and N) accounted for over 96.3% of the total chemical composition; of the mineral fraction, Na had higher accumulation in both leaves and roots. Azospirillum-inoculated and control plants had similar elemental quantities; however, in bacteria-inoculated roots, P was significantly increased (34.33%), which constitutes a major benefit for plant nutrition, while Cu content decreased (35.16%). PMID:24148195

Guerrero-Molina, M F; Lovaisa, N C; Salazar, S M; Díaz-Ricci, J C; Pedraza, R O

2014-07-01

340

Field-emission scanning electron microscopy and energy-dispersive x-ray analysis to understand the role of tannin-based dyes in the degradation of historical wool textiles.  

PubMed

An innovative approach, combining field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy (EDX) analysis, is presented to investigate the degradation mechanisms affecting tannin-dyed wool. In fact, tannin-dyed textiles are more sensitive to degradation then those dyed with other dyestuffs, even in the same conservation conditions. FESEM-EDX was first used to study a set of 48 wool specimens (artificially aged) dyed with several raw materials and mordants, and prepared according to historical dyeing recipes. EDX analysis was performed on the surface of wool threads and on their cross-sections. In addition, in order to validate the model formulated by the analysis of reference materials, several samples collected from historical and archaeological textiles were subjected to FESEM-EDX analysis. FESEM-EDX investigations enabled us to reveal the correlation between elemental composition and morphological changes. In addition, aging processes were clarified by studying changes in the elemental composition of wool from the protective cuticle to the fiber core in cross-sections. Morphological and elemental analysis of wool specimens and of archaeological and historical textiles showed that the presence of tannins increases wool damage, primarily by causing a sulfur decrease and fiber oxidation. PMID:24983911

Restivo, Annalaura; Degano, Ilaria; Ribechini, Erika; Pérez-Arantegui, Josefina; Colombini, Maria Perla

2014-10-01

341

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  

NASA Astrophysics Data System (ADS)

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 for particles generated from the deployment of these airbags to deposit on surfaces in the vehicle as the airbags deflate.1 Another paper published by Berk reported particles similar in morphology and composition to primer gunshot residue (GSR) are produced by side impact airbags.2 This paper's aim will be to show mid-point results of a study still in progress in which non-vented airbags were analyzed to determine if they exhibited the same particle depositing features as their vented airbag counterparts. Further investigation in this study is being performed to find more airbags which produce primer gunshot residue-like particles containing lead, barium, and antimony from airbag deployment. To date, the study has resulted in (1) non-vented airbags exhibiting deposition of particles suitable for SEM/EDS analysis and (2) no gunshot residue-like particles being detected from the airbag residues studied thus far.

Wyatt, J. Matney

2011-06-01

342

Dispersive wave emission and supercontinuum generation in a silicon wire waveguide pumped around the 1550 nm telecommunication wavelength  

E-print Network

We demonstrate dispersive wave generation, soliton fission and supercontinuum generation in a silicon wire at telecom wavelengths. Despite the strong nonlinear absorption inherent to silicon at telecom wavelengths, we experimentally demonstrate that the compression and subsequent splitting of higher order solitons remains possible. Moreover we observe the emission of resonant radiation from the solitons, leading to the generation a broad supercontinuum.

Leo, François; Safioui, Jassem; Kockaert, Pascal; Coen, Stéphane; Dave, Utsav; Kuyken, Bart; Roelkens, Gunther

2014-01-01

343

X-ray photoabsorption of warm dense matter  

Microsoft Academic Search

Summary form only given, as follows. Time-resolved X-ray photoabsorption enables one to probe the electronic structure of materials at high temperature and near-solid densities. X-rays from the Advanced Light Source synchrotron are focused onto a thin foil sample, dispersed by a flat-field spectrometer and detected by a streak camera. The sample is heated isochorically by a femtosecond laser pulse. A

P. A. Heimann; S. Johnson; A. Lindenberg; R. Falcone; R. Lee; A. Ng

2001-01-01

344

X-Ray Imaging Model  

NSDL National Science Digital Library

The X-Ray Imaging Model simulates the basic concepts of X-Ray imaging, exploring how different aspects of both the X-Ray source as well as the sample affect the X-Ray image. The simulation has a main window which contains the simulated image and the controls to manipulate the X-Ray characteristics and the physical characteristics of the sample to be imaged. In addition to the main panel, there are two optional windows. The first contains a graph of the X-ray spectrum and a second graph of the simulated exposure level of the film. The second optional window shows the geometry of the sample, which consists of a slab with two embedded cylinders within it. The X-Ray Imaging Model was created by Michael Gallis using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. You can examine and modify this compiled EJS model if you run the model (double click on the model's jar file), right-click within a plot, and select "Open Ejs Model" from the pop-up menu. You must, of course, have EJS installed on your computer. 

Gallis, Michael R.

2014-04-16

345

X-ray observations of ultraluminous X-ray sources  

E-print Network

Ultraluminous X-ray sources (ULXs) are amongst the most intriguing of X-ray source classes. Their extreme luminosities - greater than 10^39 erg/s in the 0.3 - 10 keV band alone - suggest either the presence of black holes larger than those regularly encountered in our own Galaxy (the Galactic centre excepted), or sources apparently radiating well above the Eddington limit. We review the insights afforded us by studies of their X-ray emission, focussing on what this reveals about the underlying compact object. In particular, we discuss recent deep observations of ULXs by the XMM-Newton observatory, and how the unprecedented data quality provided by this mission is starting to discriminate between the different physical models for these extraordinary X-ray emitters.

T. P. Roberts

2007-06-18

346

Numerical analysis for a solid-core photonic crystal fiber with tunable zero dispersion wavelengths  

NASA Astrophysics Data System (ADS)

Here we propose a simple design for a solid-core photonic crystal fiber made of silica by keeping the golden ratio (1.618) between pitch and air hole diameter ? /d in a subset of six rings of air-holes with hexagonal arrangement. In the case when we have a pitch equal to one micron (? =1 ?m), we need air-holes diameters d=0.618 ?m in order to obtain the golden ratio parameter (?/d=1.618), and achieve two zero dispersion wavelength (ZDW) points at 725 nm and 1055 nm; this gives us the possibility to use this fiber in supercontinuum generation using a laser emission close to that points. We analyzed a series of fibers using this relation and show the possibilities of tunable ZDW in a wide range of wavelengths from 725 nm to 2000 nm with low losses and small effective area. In agreement with the ZDW point needed, the geometry of the structure can be modified to the point of having only three rings of air holes that surround the solid core with low losses and good confinement mode. The design proposed here is analyzed using the finite element method (FEM) with perfectly matched layers (PML), including the material dispersion directly into the model applying the Sellmeier's equation.

Barrientos-García, A.; Sukoivanov, Igor A.; Andrade-Lucio, J. A.; Guryev, Igor; Shulika, Oleksiy V.; Hernandez-García, J. C.; Ramos-Ortiz, G.

2014-09-01

347

X-Ray spectroscopy of cooling flows  

NASA Technical Reports Server (NTRS)

Cooling flows in clusters of galaxies occur when the cooling time of the gas is shorter than the age of the cluster; material cools and falls to the center of the cluster potential. Evidence for short X-ray cooling times comes from imaging studies of clusters and X-ray spectroscopy of a few bright clusters. Because the mass accretion rate can be high (a few 100 solar mass units/year) the mass of material accumulated over the lifetime of a cluster can be as high as 10(exp 12) solar mass units. However, there is little evidence for this material at other wavelengths, and the final fate of the accretion material is unknown. X-ray spectra obtained with the Einstein SSS show evidence for absorption; if confirmed this result would imply that the accretion material is in the form of cool dense clouds. However ice on the SSS make these data difficult to interpret. We obtained ASCA spectra of the cooling flow cluster Abell 85. Our primary goals were to search for multi-temperature components that may be indicative of cool gas; search for temperature gradients across the cluster; and look for excess absorption in the cooling region.

Prestwich, Andrea

1996-01-01

348

Radio and X-ray observations of GX 339-4  

NASA Technical Reports Server (NTRS)

Observations of the Galactic black hole candidate binary system GX 339-4 at radio, optical and X-ray wavelengths are reviewed. The radio observations reveal a compact, persistent and variable source. On the average, the radio intensity is less than 10 mJy. These data, when compared with previous data, indicate no set correlation between the radio and X-ray emission. The X-ray intensity suggests a 14.5 month cycle. The latest radio observational data are presented together with X-ray data and are discussed in the context of similar correlated observations from other X-ray binaries.

Sood, R.; Durouchoux, P.; Campbell-Wilson, D.; Vilhu, O.; Wallyn, P.

1997-01-01

349

Results of X-ray and optical monitoring of SCO X-1  

NASA Technical Reports Server (NTRS)

Sco X-1 was monitored at optical and X-ray wavelengths from 1970 April 26 to 1970 May 21. The optical observations were made at six observatories around the world and the X-ray observations were made by the Vela satellites. There was a tendency for the object to show greater variability in X-ray when the object is optically bright. A discussion of the intensity histograms is presented for both the optical and X-ray observations. No evidence for optical or X-ray periodicity was detected.

Mook, D. E.; Messina, R. J.; Hiltner, W. A.; Belian, R.; Conner, J.; Evans, W. D.; Strong, I.; Blanco, V.; Hesser, J.; Kunkel, W.

1974-01-01

350

Nanoscale X-ray imaging  

NASA Astrophysics Data System (ADS)

Recent years have seen significant progress in the field of soft- and hard-X-ray microscopy, both technically, through developments in source, optics and imaging methodologies, and also scientifically, through a wide range of applications. While an ever-growing community is pursuing the extensive applications of today's available X-ray tools, other groups are investigating improvements in techniques, including new optics, higher spatial resolutions, brighter compact sources and shorter-duration X-ray pulses. This Review covers recent work in the development of direct image-forming X-ray microscopy techniques and the relevant applications, including three-dimensional biological tomography, dynamical processes in magnetic nanostructures, chemical speciation studies, industrial applications related to solar cells and batteries, and studies of archaeological materials and historical works of art.

Sakdinawat, Anne; Attwood, David

2010-12-01

351

X-Ray Imaging System  

NASA Technical Reports Server (NTRS)

The Model 60007A InnerView Real-time X-ray Imaging System, produced by National Imaging Systems, a division of FlouroScan Imaging Systems, Inc. (formerly HealthMate, Inc.), Northbrook, IL, is a third generation spinoff from x-ray astronomy technology. Goddard Space Flight Center developed the original technology into the Lixiscope, a small, portable, minimal radiation x-ray instrument that could be used at the scene of an accident. FlouroScan Imaging Systems, Inc., adapted this technology to develop the FlouroScan, a low-intensity, x-ray system that could be used without the lead aprons, film badges and lead-lined walls that conventional systems require. The InnerView is a spinoff of non-destructive testing and product inspection.

1991-01-01

352

Diffraction peaks in x ray spectroscopy: Friend or foe?  

NASA Astrophysics Data System (ADS)

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

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

353

X-ray fluorescence microscopy  

SciTech Connect

Synchrotron x-ray fluorescence microscopy is used to quantitatively measure and image the distribution of trace elements in biological, geological and materials science specimens. The design and performance of the x-ray fluorescence (XFR) microprobe at the NSLS are discussed and compared with other XRF microprobe design. An example of a trace element image obtained with this instrument if presented. 6 refs., 5 figs.

Rivers, M.L.; Sutton, S.R. (Chicago Univ., IL (USA). Dept. of Geophysical Sciences); Jones, K.W. (Brookhaven National Lab., Upton, NY (USA))

1990-10-01

354

A Study of Wavelength Calibration of NEWSIPS High-Dispersion Spectra  

E-print Network

In this study we cross-correlate many IUE echellograms of a variety of stars to evaluate systematic error sources in the wavelength zeropoint of all three cameras. We first evaluated differences between the final archived ("NEWSIPS") and the originally processed ("IUESIPS") spectra. These show a clear time dependence in zeropoint for the SWP camera due to revisions in the IUESIPS wavelength scale. Small IUESIPS - NEWSIPS differences are also found for the LWR camera. We also examined wavelength zeropoint disparities between data obtained both through the small and large entrance apertures and for observations made by different target acquisition modes for faint and bright stars. We found that velocities resulting from these alternative observing modes are nil. For large-aperture observations the dominant error source is the target position placement in the aperture. We searched for spurious trends with time, and found only a suggestion of time trends for faint stars observed with the SWP camera. We also discovered 1-day, +/-3 km/s sinusoidsal patterns in intensive monitoring data which are ascribable to changes in telescope focus resulting from thermal drifts. In the second part of the paper, we measured mean zeropoint errors of NEWSIPS echellogram data against laboratory results by using the GHRS spectral atlas of the 10 Lac. We find that the derived apparent velocity difference for this star is -1 +/-3.5 km/s. Several less precise comparisons lead to similar results. The zeropoints of the NEWSIPS-processed LWP/LWR cameras are evaluated and are also found to be nearly zero (+/-5 km/s) relative to HST atlases of Arcturus and Procyon atlas. These results do not support result by Gonzalez-Riestra et al. that corrections should be introduced to the wavelength scales of various NEWSIPS high-dispersion data products.

Myron A. Smith

2001-04-03

355

X Rays: Another Form of Light  

NSDL National Science Digital Library

This Chandra X-ray Observatory website gives a brief history on the discovery of X-rays and how they are produced. There is also information on other forms of light. This website includes illustrations and information on X- ray production, inverse Compton scattering, atomic emission, and synchrotron radiation. There are also links to learn more about the differences between x-ray astronomy and medical x-rays, and to a word search for x-rays and light.

2004-11-17

356

The X-ray cluster Abell 744  

NASA Technical Reports Server (NTRS)

X-ray and optical observations of the cluster of galaxies Abell 744 are presented. The X-ray flux (assuming H(0) = 100 km/s per Mpc) is about 9 x 10 to the 42nd erg/s. The X-ray source is extended, but shows no other structure. Photographic photometry (in Kron-Cousins R), calibrated by deep CCD frames, is presented for all galaxies brighter than 19th magnitude within 0.75 Mpc of the cluster center. The luminosity function is normal, and the isopleths show little evidence of substructure near the cluster center. The cluster has a dominant central galaxy, which is classified as a normal brightest-cluster elliptical on the basis of its luminosity profile. New redshifts were obtained for 26 galaxies in the vicinity of the cluster center; 20 appear to be cluster members. The spatial distribution of redshifts is peculiar; the dispersion within the 150 kpc core radius is much greater than outside. Abell 744 is similar to the nearby cluster Abell 1060.

Kurtz, M. J.; Huchra, J. P.; Beers, T. C.; Geller, M. J.; Gioia, I. M.

1985-01-01

357

The role of EBIT in X-ray laser research  

SciTech Connect

Back in the early 1980's the X-ray laser program required a new level of understanding and measurements of the atomic physics of highly charged ions. The electron-beam ion trap (EBIT) was developed and built at Lawrence Livermore National Laboratory (LLNL) as part of the effort to understand and measure the cross sections and wavelengths of highly charged ions. In this paper we will discuss some of the early history of EBIT and how it was used to help in the development of X-ray lasers. EBIT's capability was unique and we will show some of the experimental results obtained over the years that were done related to X-ray lasers. As X-ray lasers have now become a table-top tool we will show some new areas of research that involve understanding the index of refraction in partially ionized plasmas and suggest new areas where EBIT may be able to contribute.

Nilsen, J

2007-01-25

358

Characterization of HgIâ single crystals and detectors by x-ray rocking curve analysis and x-ray reflection topography  

Microsoft Academic Search

An attempt has been made to establish a correlation between the results of x-ray rocking curves and x-ray reflection topographs for vapor grown HgIâ, single crystals. X-ray rocking curves were obtained by double crystal spectroscopy with Si as the first crystal and topographs were produced using the Berg-Barrett technique with an asymmetrically cut Si-disperser. The crystals were evaluated at different

R. Ostrom; L. Keller; N. J. Wagner; M. M. Schieber; C. Ortale; L. van den Berg; W. F. Schnepple

1987-01-01

359

The structure and evolution of X-ray clusters  

NASA Technical Reports Server (NTRS)

Observations of the structure of the X-ray emission from 12 nearby rich clusters of galaxies are presented and interpreted in terms of dynamic cluster evolution. X-ray structures revealed by the Einstein Observatory imaging proportional counter in the range 0.25 to 3.0 keV were analyzed and used to classify the clusters based on their X-ray morphologies. Four categories are observed, consisting of spiral-rich clusters with low X-ray temperatures and velocity dispersions with broad and highly clumped emission, spiral-poor clusters with high X-ray temperatures and velocity dispersions with smoothly varying emission broadly or sharply peaked around a dominant galaxy, and clusters with emission typical of a cD galaxy in a poor cluster or group. The broad, highly clumped cluster emission is interpreted as a result of an early evolutionary stage, while the cD and centrally enhanced emissions represent successive later stages in X-ray galactic cluster evolution.

Jones, C.; Mandel, E.; Schwarz, J.; Forman, W.; Murray, S. S.; Harnden, F. R., Jr.

1979-01-01

360

First Terrestrial Soft X-ray Aurora Observations by Chandra  

NASA Technical Reports Server (NTRS)

Northern polar "auroral" regions of Earth was observed by High-Resolution Camera in imaging mode (T32C-I) aboard Chandra X-Ray Observatory (CXO) during mid December 2003 - mid April 2004. Ten CXO observations, each approximately 20 min duration, were made in a non-conventional method (due to CXO technical issues), such that Chandra was aimed at a fixed point in sky and the Earth's polar cusp was allowed to drift through the HRC-I field-of-view. The observations were performed when CXO was near apogee and timed during northern winter mostly near midnight (6 hr), except two observations which occurred around 1200 UT, so that northern polar region is entirely in dark and solar fluoresced x-ray contamination can be avoided. These observations were aimed at searching the Earth's soft x-ray aurora and to do a comparative study with Jupiter's x-ray aurora, where a pulsating x-ray hot-spot near the northern magnetic pole has been observed by Chandra that implies a particle source region near Jupiter's magnetopause, and entry of heavy solar wind ions due to high-latitude reconnection as a viable explanation for the soft x-ray emissions. The first Chandra soft (0.1-2 keV) x-ray observations of Earth's aurora show that it is highly variable (intense arc, multiple arcs, diffuse, at times almost absent). In at least one of the observations an isolated blob of emission is observed where we expect cusp to be: giving indication of solar wind charge-exchange signature in x-rays. We are comparing the Chandra x-ray observations with observations at other wavelengths and particle data from Earth-orbiting satellites and solar wind measurements from near-Earth ACE and SOH0 spacecraft. Preliminary results from these unique CXO-Earth observations will be presented and discussed.

Bhardwaj, Anil; Elsner, Ronald F.; Gladstone, G. Randall; Waite, J. Hunter, Jr.; Cravens, Thomas E.; Ostgaard, Nikolai; Chang, Shen-Wu; Metzger, Albert E.; Majeed, Tariq

2004-01-01

361

Simulation of the fundamental and nonlinear harmonic output from an FEL amplifier with a soft x-ray seed laser  

SciTech Connect

A single-pass, high-gain free-electron laser (FEL) x-ray amplifier was simulated using the 3D, polychromatic simulation code MEDUSA. The seed for the system is a table-top, soft x-ray laser. The simulated fundamental and nonlinear harmonic x-ray output wavelengths are discussed.

Biedron, S. G.; Freund, H. P.; Li, Y.; Milton, S. V.

2000-07-05

362

X-ray Free-electron Lasers  

SciTech Connect

We review the present status and properties of X-ray free-electron lasers in operation or under construction in the nanometer and sub-nanometer wavelength range, and the novel possibilities they offer for the study of atomic and molecular processes. We also discuss recent developments in relativistic electron beam physics that give us the possibility of designing a new generation of X-ray free-electron lasers that: a. are more compact; b. reduce the radiation pulse duration to one femtosecond or below; c. extend the photon energy to the 50 keV region. These results are obtained by reducing the electron bunch charge while at same time maximizing the beam brightness and reducing the bunch length to a value near or smaller than the free-electron laser cooperation length. In the last case the radiation pulse is fully coherent in the longitudinal and transverse space. The increase in beam brightness can also be used to reduce the beam energy needed for a given radiation wavelength, when, at the same time, the undulator period is reduced. The simultaneous decrease in beam energy and undulator period leads to a more compact free-electron laser, while the high beam brightness reduces the gain length and increases the coherent radiation intensity.

Pellegrini, Claudio [UCLA Department of Physics and Astronomy, Los Angeles, CA 90095-1547 (United States)

2009-09-10

363

Multispectral glancing incidence X-ray telescope  

NASA Technical Reports Server (NTRS)

A multispectural glancing incidence X-ray telescope is illustrated capable of broadband, high-resolution imaging of solar and stellar X-ray and extreme ultraviolet radiation sources which includes a primary optical system preferably of the Wolter I type having a primary mirror system. The primary optical system further includes an optical axis having a primary focus at which the incoming radiation is focused by the primary mirrors. A plurality of ellipsoidal mirrors are carried at an inclination to the optical axis behind the primary focus. A rotating carrier is provided on which the ellipsoidal mirrors are carried so that a desired one of the ellipsoidal mirrors may be selectively positioned in front of the incoming radiation beam. In the preferred embodiment, each of the ellipsoidal mirrors has an identical concave surface carrying a layered synthetic microstructure coating tailored to reflect a desired wavelength of 1.5A or longer. Each of the identifical ellipsoidal mirrors has a second focus at which a detector is carried. Thus the different wavelength image is focused upon the detector irregardless of which mirror is positioned in front of the radiation beam.

Hoover, R. B. (inventor)

1986-01-01

364

An X-ray BBB Michelson interferometer.  

PubMed

A new X-ray Michelson interferometer based on the BBB interferometer of Bonse and Hart and designed for X-rays of wavelength approximately 1 A was described in a previous paper. Here, a further test carried out at the SPring-8 1 km beamline BL29XUL is reported. One of the BBB's mirrors was displaced by a piezo to introduce the required path-length difference. The resulting variation of intensity with piezo voltage as measured by an avalanche photodiode could be ascribed to the phase variation resulting from the path-length change, with a small additional contribution from the change of the position of the lattice planes of the front mirror relative to the rest of the crystal. This 'Michelson fringe' interpretation is supported by the observed steady movement across the output beam of the interference fringes produced by a refractive wedge when the piezo voltage was ramped. The front-mirror displacement required for one complete fringe at the given wavelength is only 0.675 A; therefore, a quiet environment is vital for operating this device, as previous experiments have shown. PMID:15310953

Sutter, John P; Ishikawa, Tetsuya; Kuetgens, Ulrich; Materlik, Gerhard; Nishino, Yoshinori; Rostomyan, Armen; Tamasaku, Kenji; Yabashi, Makina

2004-09-01

365

Champlane X-ray Analysis  

NASA Astrophysics Data System (ADS)

We summarize the X-ray analysis results of the Chandra Multiwavelength Plane survey (ChaMPlane), which is to constrain low luminosity accretion source content in the Galaxy using the Chandra archival data and optical and IR follow-up observations. From the Chandra archival data (A01-A06), we have detected more than 12000 point sources over 105 distinct fields (156 observations) covering 8 deg^2 in the Galactic Plane. The source catalog and X-ray results are available through our project website (http://hea-www.cfa.harvard.edu/ChaMPlane/). We highlight some of X-ray analysis findings and outline the future plan. For many X-ray sources with no reliable counterpart from optical or IR observations, X-ray driven source properties are the only hint to the nature of the sources. Therefore, we introduce a quantile-based technique to drive extinction and spectral parameters of each source, which allows to estimate the flux and distance of the source.

Hong, JaeSub; Grindlay, J.; van den Berg, M.; Laycock, S.; Koenig, X.; Zhao, P.; Schlegel, E.

2006-06-01

366

IUE short-wavelength high-dispersion line list for the symbiotic nova RR Telescopii  

NASA Technical Reports Server (NTRS)

An 820 minute and other long-exposure archival SWP IUE high-dispersion spectra of symbiotic star RR Tel have been combined to form a composite spectrum. In most of these spectra many lines are saturated, but weaker features appear above the continuum. Their wavelengths were measured from the composite spectrum and compared with the line list from a thorough study of RR Tel by Penston et al. (1983). Among the revised line list are 22 new line identifications from ions C III, O I, N I, Mg VI, Si I, S I, S IV, Fe II, and Ni II. N I exists inside RR Tel's H II region and is pumped by the hot component's continuum. The fluxes for all the lines in each of the spectra are presented. All of the observed ions show a secular flux decrease between 1978 and 1988. A list of SWP high-dispersion camera artifacts is also presented. The list was generated by comparing RR Tel spectra to a long-exposure sky flat.

Aufdenberg, Jason P.

1993-01-01

367

Light collection enhancement of the digital x-ray detector using Gd 2O 2S:Tb and CsI:Tl phosphors in the aspect of nano-scale light dispersions  

NASA Astrophysics Data System (ADS)

The nano-scopic light collection is investigated for the Active Matrix Flat-Panel Imagers (AMFPIs). The simulations using two kinds of screens are shown for light collection of x-rays. Enhancement of the light collection is accomplished by the microlens system incorporated with x-ray detector. For digital radiographic and mammographic applications, indirect detection imagers use Gd 2O 2S:Tb or CsI:Tl scintillation screens to convert the x-ray into visible photons. The light collection efficiencies for Gd 2O 2S and CsI are obtained. In Gd 2O 2S, the 27 kVp and 82 ?m are the highest light collection cases in both Lambertian and Isotropic geometries. In CsI, 20 keV and 150 ?m case have the highest light collection efficiency. So, x-ray energy and scintillator thicknesses are considered as the optimized light collection. The optimum thickness and x-ray energy combination are used for the detector of this study. In this paper, it is concluded that the screens between 17 kVp and 25 kVp have higher light collections, which could be considered as the clinical purposes if it is necessary. This energy range is compared with other energy cases, which are examined in the study.

Woo, Taeho; Kim, Taewoo

2012-01-01

368

Roentgen's Discovery of the x-ray  

NSDL National Science Digital Library

The text in this site describes how Roentgen's discovered x-rays, how he created the first x-ray image, and how he investigated x-ray properties. Early medical applications are explained. Also, the site contains a link to a small gallery of historical x-ray images.

2013-06-26

369

Cosmic X-ray physics  

NASA Technical Reports Server (NTRS)

The analysis of the beryllium-filtered data from Flight 17.020 was completed. The data base provided by the Wisconsin diffuse X-ray sky survey is being analyzed by correlating the B and C band emission with individual velocity components of neutral hydrogen. Work on a solid state detector to be used in high resolution spectroscopy of diffuse or extend X-ray sources is continuing. A series of 21 cm observations was completed. A paper on the effects of process parameter variation on the reflectivity of sputter-deposited tungsten-carvon multilayers was published.

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

1986-01-01

370

Recent Progress in X-Ray Laser Research in JAEA  

NASA Astrophysics Data System (ADS)

Recent progress in x-ray laser (XRL) research in Japan Atomic Energy Agency (JAEA) is reviewed. The repetition-rate of the x-ray laser has been improved from each0 minutes to0 seconds (0.1 Hz) by installing new driver laser, TOPAZ, which allows us to promote the applications of fully spatial coherent3.9 nm laser in the wide variety of research fields such as material science, single-shot x-ray holography and atomic physics. In order to improve the present performance of the x-ray lasers, we have investigated the possibilities of the enhancement of the peak brilliance using v-groove target and the generation of circularly polarized x-ray laser under a strong magnetic field. Towards shorter wavelength x-ray lasers, we have investigated several schemes. One is the use of reflection of the light by relativistic plasma mirror driven by laser-wake-field, and the other is photo-pumping scheme using K? emission from a solid target.

Kawachi, T.; Kishimoto, M.; Kado, M.; Hasegawa, N.; Tanaka, M.; Ochi, Y.; Nishikino, M.; Ishino, M.; Imazono, T.; Ohba, T.; Kunieda, Y.; Faenov, A.; Pikuz, T.; Namikawa, K.; Namba, S.; Kato, Y.; Nishimura, H.; Sarukura, N.; Kando, M.; Fukuda, Y.; Kotaki, H.; Pirozhkov, A.; Ma, J.; Sagisaka, A.; Mori, M.; Koga, J.; Bulanov, S.; Daido, H.; Tajima, T.

371

Soft x-ray holography and microscopy of biological cells  

Microsoft Academic Search

Some experimental results on soft X-ray microscopy and holography imaging of biological specimens are presented in the paper. As we know, due to diffraction effects, there exists a resolution limit determined by wavelength lambda and numerical aperture NA in conventional optical microscopy. In order to improve resolution, the num erical aperture should be made as large as possible and the

Jianwen Chen; Hongyi Gao; Honglan Xie; Ruxin Li; Zhizhan Xu

2003-01-01

372

Condensed matter physics using a coherent X-ray source  

Microsoft Academic Search

A tunable coherent light source providing X-rays at wavelengths down to 1 Å with high brilliance and femtosecond time-resolution would open up new and unprecedented research opportunities in condensed matter physics. Here we review a few of these opportunities and speculate on possible future developments.

I. Lindau

1997-01-01

373

Modeling the Radio to X-ray SED of Galaxies  

E-print Network

Our multi-wavelength model GRASIL for the SED of galaxies is described, in particular the recent extension to the radio and X-ray range. With our model we can study different aspects of galaxy evolution by exploiting all available spectral observations, where different emission components dominate.

L. Silva; G. L. Granato; A. Bressan; P. Panuzzo

2002-08-17

374

Computed tomography of cryogenic biological specimens based on X-ray microscopic images  

Microsoft Academic Search

Soft X-ray microscopy employs the photoelectric absorption contrast between water and protein in the 2.34–4.38nm wavelength region to visualize protein structures down to 30nm size without any staining methods. Due to the large depth of focus of the Fresnel zone plates used as X-ray objectives, computed tomography based on the X-ray microscopic images can be used to reconstruct the local

D Weiß; G Schneider; B Niemann; P Guttmann; D Rudolph; G Schmahl

2000-01-01

375

Optimization for Single-Spike X-Ray FELs at LCLS with a Low Charge Beam  

Microsoft Academic Search

The Linac Coherent Light Source is an x-ray free-electron laser at the SLAC National Accelerator Laboratory, which is operating at x-ray wavelengths of 20-1.2 Angstrom with peak brightness nearly ten orders of magnitude beyond conventional synchrotron radiation sources. At the low charge operation mode (20 pC), the x-ray pulse length can be <10 fs. In this paper we report our

Lanfa

2011-01-01

376

X-ray exposure sensor and controller  

NASA Technical Reports Server (NTRS)

An exposure controller for x-ray equipment is provided, which comprises a portable and accurate sensor which can be placed adjacent to and directly beneath the area of interest of an x-ray plate, and which measures the amount of exposure received by that area, and turns off the x-ray equipment when the exposure for the particular area of interest on the x-ray plate reaches the value which provides an optimal x-ray plate.

Berdahl, C. Martin (Inventor)

1977-01-01

377

Imaging X-ray Thomson Scattering Spectrometer Design and Demonstration  

SciTech Connect

In many laboratory astrophysics experiments, intense laser irradiation creates novel material conditions with large, one-dimensional gradients in the temperature, density, and ionization state. X-ray Thomson scattering is a powerful technique for measuring these plasma parameters. However, the scattered signal has previously been measured with little or no spatial resolution, which limits the ability to diagnose inhomogeneous plasmas. We report on the development of a new imaging x-ray Thomson spectrometer (IXTS) for the Omega laser facility. The diffraction of x-rays from a toroidally-curved crystal creates high-resolution images that are spatially resolved along a one-dimensional profile while spectrally dispersing the radiation. This focusing geometry allows for high brightness while localizing noise sources and improving the linearity of the dispersion. Preliminary results are presented from a scattering experiment that used the IXTS to measure the temperature profile of a shocked carbon foam.

Gamboa, E.J. [University of Michigan; Huntington, C.M. [University of Michigan; Trantham, M.R. [University of Michigan; Keiter, P.A [University of Michigan; Drake, R.P. [University of Michigan; Montgomery, David [Los Alamos National Laboratory; Benage, John F. [Los Alamos National Laboratory; Letzring, Samuel A. [Los Alamos National Laboratory

2012-05-04

378

Tokamak physics studies using x-ray diagnostic methods  

SciTech Connect

X-ray diagnostic measurements have been used in a number of experiments to improve our understanding of important tokamak physics issues. The impurity content in TFTR plasmas, its sources and control have been clarified through soft x-ray pulse-height analysis (PHA) measurements. The dependence of intrinsic impurity concentrations and Z/sub eff/ on electron density, plasma current, limiter material and conditioning, and neutral-beam power have shown that the limiter is an important source of metal impurities. Neoclassical-like impurity peaking following hydrogen pellet injection into Alcator C and a strong effect of impurities on sawtooth behavior were demonstrated by x-ray imaging (XIS) measurements. Rapid inward motion of impurities and continuation of m = 1 activity following an internal disruption were demonstrated with XIS measurements on PLT using injected aluminum to enhance the signals. Ion temperatures up to 12 keV and a toroidal plasma rotation velocity up to 6 x 10/sup 5/ m/s have been measured by an x-ray crystal spectrometer (XCS) with up to 13 MW of 85-keV neutral-beam injection in TFTR. Precise wavelengths and relative intensities of x-ray lines in several helium-like ions and neon-like ions of silver have been measured in TFTR and PLT by the XCS. The data help to identify the important excitation processes predicted in atomic physics. Wavelengths of n = 3 to 2 silver lines of interest for x-ray lasers were measured, and precise instrument calibration techniques were developed. Electron thermal conductivity and sawtooth dynamics have been studied through XIS measurements on TFTR of heat-pulse propagation and compound sawteeth. A non-Maxwellian electron distribution function has been measured, and evidence of the Parail-Pogutse instability identified by hard x-ray PHA measurements on PLT during lower-hybrid current-drive experiments.

Hill, K.W.; Bitter, M.; von Goeler, S.; Beiersdorfer, P.; Fredrickson, E.; Hsuan, H.; McGuire, K.; Sauthoff, N.R.; Sesnic, S.; Stevens, J.E.

1987-03-01

379

X-rays from Planetary Exospheres: What we can Learn  

NASA Astrophysics Data System (ADS)

X-ray observations have opened up a completely new possibility of remote global imaging of planetary exospheres and their spatial and temporal variability. The talk will focus on the planets Venus and Mars, where the absence of a global magnetic field enables a straightforward study of how a planetary atmosphere responds to the incident solar photon and ion flux. Chandra was the first satellite to detect X-rays from Venus and Mars and to reveal that they are the result of two different processes: scattering of solar X-rays and charge exchange reactions between highly charged heavy ions in the solar wind with atmospheric neutrals. As a consequence of the characteristic photoabsorption cross sections, scattering of solar X-rays is most efficient at atmospheric heights of 100-140 km, i.e., well above the cloud layers. Here, X-rays provide direct observational access to regions which are difficult to study by in-situ measurements or by remote observations at other wavelengths. X-ray observations of charge exchange reactions in planetary exospheres have a particulary high scientific potential, because this process is considered as an important nonthermal escape mechanism, which may be responsible for a significant loss of the atmosphere. Although this process is mainly due to charge exchange with solar wind protons, which are about 1000 times more abundant than heavy ions and which do not produce X-rays, the high cross section makes charge exchange an efficient tracer of planetary outgassing, thus linking X-ray astrophysics to astrobiology.

Dennerl, Konrad

2011-05-01

380

High-intensity laser synchrotron x-ray source  

SciTech Connect

A laser interacting with a relativistic electron beam behaves like a virtual wiggler of an extremely short period equal to half of the laser wavelength. This approach opens a route to relatively compact, high-brightness x-ray sources alternative or complementary to conventional synchrotron light sources. Although not new, the Laser Synchrotron Light Source (LSLS) concept is still waiting for a convincing demonstration. Available at the BNL`s Accelerator Test Facility (ATF), a high-brightness electron beam and the high-power C0{sub 2} laser may be used as prototype LSLS brick stones. In a feasible demonstration experiment, 10-GW, 100-ps C0{sub 2} laser beam will be brought to a head-on collision with a 10-ps, 0.5-nC, 70 MeV electron bunch. Flashes of well-collimated, up to 9.36-keV ({approximately}{Angstrom}) x-rays of 10-ps pulse duration, with a flux of {approximately}10{sup 19} photons/sec will be produced via linear Compton backscattering. The x-ray spectrum is tunable proportionally to a variable e-beam energy. A natural short-term extension of the proposed experiment would be further enhancement of the x-ray flux to a 10{sup 21}{minus}10{sup 22} photons/sec level, after the ongoing ATF CO{sub 2} laser upgrade to 1 TW peak power and electron bunch shortening to 3 ps. The ATF LSLS x-ray beamline, exceeding by orders of magnitude the peak fluxes attained at the National Synchrotron Light Source (NSLS) x-ray storage ring, may become attractive for certain users, e.g., for biological x-ray microscopy. In addition, a terawatt CO{sub 2} laser will enable harmonic multiplication of the x-ray spectrum via nonlinear Compton scattering.

Pogorelsky, I.V.

1995-10-01

381

X-ray afterglow light curves : toward standard candle ?  

E-print Network

We investigate the clustering of afterglow light curves observed at X-ray and optical wavelengths. We have constructed a sample of 61 bursts with known dis tance and X-ray afterglow. This sample includes bursts observed by BeppoSAX, XMM-Newton, Chandra, and SWIFT. We correct the light curves for cosmological ef fects and compare the observed X-ray fluxes one day after the burst. We check for correlations between the observed flux and the burst spectral and temporal properties. We confirm the previous result of Boer and Gendre (2000) that X-ray afterglow light curves cluster in luminosity, even when we consider the l ast SWIFT data. We observe this clustering only for the afterglow light curves; the inclusion of prompt-related data broaden the distribution. A similar clu stering is observed for the optical light curves; GRB sources can be divided in three classes, namely optical and X-ray bright afterglows, optical and X-ray dim ones, and optically bright -X-ray dim ones. We argue that this clustering is related to the fireball total energy, the external medium density, the fraction of fireball energy going in relativistic electrons and magnetic fields. These parameters can be either fixed to a standard va lue, or correlated. We finally propose a method for the estimation of the GRB source redshift based on the observed X-ray flux one day after the burst and optical properties. Using this method, we compute a redshift of 1.4 +/- 0.2 for GRB 980519 and of 1.9 \\+/- 0.3 for GRB 040827. We tested this method on three recently detected SWIFT GRBs with known redshift, and found it in good agreement with the reported distance from optical spectroscopy .

B. Gendre; A. Galli; M. Boer

2007-11-14

382

Compact x-ray source and panel  

DOEpatents

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

Sampayon, Stephen E. (Manteca, CA)

2008-02-12

383

Anomalous lattice expansion in yttria stabilized zirconia under simultaneous applied electric and thermal fields: A time-resolved in situ energy dispersive x-ray diffractometry study with an ultrahigh energy synchrotron probe  

SciTech Connect

Nonisothermal densification in 8% yttria doped zirconia (8YSZ) particulate matter of 250 nm median particle size was studied under 215 V/cm dc electric field and 9 Degree-Sign C/min heating rate, using time-resolved in-situ high temperature energy dispersive x-ray diffractometry with a polychromatic 200 keV synchrotron probe. Densification occurred in the 876-905 Degree-Sign C range, which resulted in 97% of the theoretical density. No local melting at particle-particle contacts was observed in scanning electron micrographs, implying densification was due to solid state mass transport processes. The maximum current draw at 905 Degree-Sign C was 3 A, corresponding to instantaneous absorbed power density of 570 W/cm{sup 3}. Densification of 8YSZ was accompanied by anomalous elastic volume expansions of the unit cell by 0.45% and 2.80% at 847 Degree-Sign C and 905 Degree-Sign C, respectively. The anomalous expansion at 905 Degree-Sign C at which maximum densification was observed is characterized by three stages: (I) linear stage, (II) anomalous stage, and (III) anelastic recovery stage. The densification in stage I (184 s) and II (15 s) was completed in 199 s, while anelastic relaxation in stage III lasted 130 s. The residual strains ({epsilon}) at room temperature, as computed from tetragonal (112) and (211) reflections, are {epsilon}{sub (112)} = 0.05% and {epsilon}{sub (211)} = 0.13%, respectively. Time dependence of (211) and (112) peak widths ({beta}) show a decrease with both exhibiting a singularity at 905 Degree-Sign C. An anisotropy in (112) and (211) peak widths of {l_brace} {beta}{sub (112)}/{beta}{sub (211)}{r_brace} = (3:1) magnitude was observed. No phase transformation occurred at 905 Degree-Sign C as verified from diffraction spectra on both sides of the singularity, i.e., the unit cell symmetry remains tetragonal. We attribute the reduction in densification temperature and time to ultrafast ambipolar diffusion of species arising from the superposition of mass fluxes due to Fickian diffusion, thermodiffusion (Soret effect), and electromigration, which in turn are a consequence of a superposition of chemical, temperature, and electrical potential gradients. On the other hand, we propose defect pile-up at particle-particle contacts and subsequent tunneling as a mechanism creating the 'burst-mode' discontinuous densification at the singularities observed at 847 and 905 Degree-Sign C.

Akdogan, E. K.; Savkl Latin-Small-Letter-Dotless-I y Latin-Small-Letter-Dotless-I ld Latin-Small-Letter-Dotless-I z, I.; Bicer, H.; Paxton, W.; Toksoy, F.; Tsakalakos, T. [Department of Materials Science and Engineering, Rutgers University, Piscataway, New Jersey 08854-8065 (United States)] [Department of Materials Science and Engineering, Rutgers University, Piscataway, New Jersey 08854-8065 (United States); Zhong, Z. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)] [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)

2013-06-21

384

Anomalous lattice expansion in yttria stabilized zirconia under simultaneous applied electric and thermal fields: A time-resolved in situ energy dispersive x-ray diffractometry study with an ultrahigh energy synchrotron probe  

NASA Astrophysics Data System (ADS)

Nonisothermal densification in 8% yttria doped zirconia (8YSZ) particulate matter of 250 nm median particle size was studied under 215 V/cm dc electric field and 9 °C/min heating rate, using time-resolved in-situ high temperature energy dispersive x-ray diffractometry with a polychromatic 200 keV synchrotron probe. Densification occurred in the 876-905 °C range, which resulted in 97% of the theoretical density. No local melting at particle-particle contacts was observed in scanning electron micrographs, implying densification was due to solid state mass transport processes. The maximum current draw at 905 °C was 3 A, corresponding to instantaneous absorbed power density of 570 W/cm3. Densification of 8YSZ was accompanied by anomalous elastic volume expansions of the unit cell by 0.45% and 2.80% at 847 °C and 905 °C, respectively. The anomalous expansion at 905 °C at which maximum densification was observed is characterized by three stages: (I) linear stage, (II) anomalous stage, and (III) anelastic recovery stage. The densification in stage I (184 s) and II (15 s) was completed in 199 s, while anelastic relaxation in stage III lasted 130 s. The residual strains (?) at room temperature, as computed from tetragonal (112) and (211) reflections, are ?(112) = 0.05% and ?(211) = 0.13%, respectively. Time dependence of (211) and (112) peak widths (?) show a decrease with both exhibiting a singularity at 905 °C. An anisotropy in (112) and (211) peak widths of {?(112)/?(211)} = (3:1) magnitude was observed. No phase transformation occurred at 905 °C as verified from diffraction spectra on both sides of the singularity, i.e., the unit cell symmetry remains tetragonal. We attribute the reduction in densification temperature and time to ultrafast ambipolar diffusion of species arising from the superposition of mass fluxes due to Fickian diffusion, thermodiffusion (Soret effect), and electromigration, which in turn are a consequence of a superposition of chemical, temperature, and electrical potential gradients. On the other hand, we propose defect pile-up at particle-particle contacts and subsequent tunneling as a mechanism creating the "burst-mode" discontinuous densification at the singularities observed at 847 and 905 °C.

Akdo?an, E. K.; ?avkl?y?ld?z, ?.; Biçer, H.; Paxton, W.; Toksoy, F.; Zhong, Z.; Tsakalakos, T.

2013-06-01

385

X-Ray Properties of Plastically Deformed LiF  

Microsoft Academic Search

Plastic deformation may be introduced in LiF single crystals by abrading, quenching, or bending. For x-ray wavelengths of about 1.5 AU(CuK?) the diffracting power is increased about 4 times by any of the three methods. For shorter wavelengths of about 0.7 au(MoK?) the increase in diffracting power is about 4, 7, and 10 times for abrading, quenching, and bending, respectively.

L. S. Birks; R. T. Seal

1957-01-01

386

X-ray microscopy of inertial fusion targets using a laser-produced plasma as an x-ray source  

SciTech Connect

With the advent of an ablation layer coating technology for mechanically nonsupported inertial fusion targets, the conventional optical interferometric technique for the characterization of these targets is no longer feasible since the batch process of this bounce coating technique makes it difficult to account for individual targets. A soft x-ray contact microradiography method, which was developed for this purpose, is limited in resolution by the 0.5-..mu..m grain size of the photographic medium used. Utilization of an x-ray sensitive photoresist extends the resolution to as low as 50 A. The use of a laser-generated x-ray source for x-ray microscopy appears to require much less energy than published photoresist sensitivity data. A single-shot exposure of 100 J, 0.527-..mu..m wavelength, and 1-ns laser shot suffices for image formation. The resulting x-ray micrographs show a higher spatial resolution than the images obtained by previous radiography techniques. The resolution of 0.2 ..mu..m in the present study is due to the finite size of the x-ray source.

Kim, H.; Wittman, M.D.

1987-07-01

387

Focused X-ray source  

DOEpatents

Disclosed is an intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator. 8 figs.

Piestrup, M.A.; Boyers, D.G.; Pincus, C.I.; Maccagno, P.

1990-08-21

388

Lights, X-rays, oxygen!  

PubMed

Photosystem II uses metal ions to oxidize water to form O2. Two recent papers employ the new technique of serial femtosecond crystallography utilizing X-ray free-electron lasers and nanocrystals to obtain initial structures of intermediate states of photosystem II catalysis at the site of oxygen production. PMID:25126779

Jez, Joseph M; Blankenship, Robert E

2014-08-14

389

Focused X-ray source  

DOEpatents

An intense, relatively inexpensive X-ray source (as compared to a synchrotron emitter) for technological, scientific, and spectroscopic purposes. A conical radiation pattern produced by a single foil or stack of foils is focused by optics to increase the intensity of the radiation at a distance from the conical radiator.

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

1990-01-01

390

The SWIRE/Chandra Survey: The X-ray Sources  

NASA Astrophysics Data System (ADS)

We report a moderate-depth (70 ks), contiguous 0.7 deg2 Chandra survey in the Lockman Hole Field of the Spitzer/SWIRE Legacy Survey coincident with a completed, ultra-deep VLA survey with deep optical and near-infrared imaging in-hand. The primary motivation is to distinguish starburst galaxies and active galactic nuclei (AGNs), including the significant, highly obscured (log N H > 23) subset. Chandra has detected 775 X-ray sources to a limiting broadband (0.3-8 keV) flux ~4 × 10-16 erg cm-2 s-1. We present the X-ray catalog, fluxes, hardness ratios, and multi-wavelength fluxes. The log N versus log S agrees with those of previous surveys covering similar flux ranges. The Chandra and Spitzer flux limits are well matched: 771 (99%) of the X-ray sources have infrared (IR) or optical counterparts, and 333 have MIPS 24 ?m detections. There are four optical-only X-ray sources and four with no visible optical/IR counterpart. The very deep (~2.7 ?Jy rms) VLA data yield 251 (>4?) radio counterparts, 44% of the X-ray sources in the field. We confirm that the tendency for lower X-ray flux sources to be harder is primarily due to absorption. As expected, there is no correlation between observed IR and X-ray fluxes. Optically bright, type 1, and red AGNs lie in distinct regions of the IR versus X-ray flux plots, demonstrating the wide range of spectral energy distributions in this sample and providing the potential for classification/source selection. Many optically bright sources, which lie outside the AGN region in the optical versus X-ray plots (fr /fx >10), lie inside the region predicted for red AGNs in IR versus X-ray plots, consistent with the presence of an active nucleus. More than 40% of the X-ray sources in the VLA field are radio-loud using the classical definition, RL . The majority of these are red and relatively faint in the optical so that the use of RL to select those AGNs with the strongest radio emission becomes questionable. Using the 24 ?m to radio flux ratio (q 24) instead results in 13 of the 147 AGNs with sufficient data being classified as radio-loud, in good agreement with the ~10% expected for broad-lined AGNs based on optical surveys. We conclude that q 24 is a more reliable indicator of radio-loudness. Use of RL should be confined to the optically selected type 1 AGN.

Wilkes, Belinda J.; Kilgard, Roy; Kim, Dong-Woo; Kim, Minsun; Polletta, Mari; Lonsdale, Carol; Smith, Harding E.; Surace, Jason; Owen, Frazer N.; Franceschini, A.; Siana, Brian; Shupe, David

2009-12-01

391

Planetary Science Advances with the International X-ray Observatory  

NASA Astrophysics Data System (ADS)

X-ray studies of planetary systems are beginning to provide important insights inaccessible at other wavelengths. In our Solar System, charge exchange emission from solar particles is faint and variable with complex spectra, a situation well-matched to the planned International X-ray Observatory's high-throughput and high spectral resolution. Solar-type stars universally exhibit enhanced magnetic activity during their youth so that X-ray studies reveal the high-energy inputs to protoplanetary disks and planetary atmospheres. It is possible that X-ray illumination is a critical regulator to the formation of planets. This paper is based on the report of the Con-X ``Solar System, Planet Formation and Evolution'' Science Panel. (1) X-ray irradiation of protoplanetary disks can be probed with the 6.4 keV iron fluorescent line. Seen in a handful of protostars with Chandra and XMM, IXO will survey the line in hundreds of young stellar systems and will quantify the 10-30 keV emission stellar emission that can penetrate deep into the disk. In a few cases, X-ray `superflares' will permit disk reverberation mapping. Combined with infrared and submillimeter studies, IXO will establish the importance of X-ray illumination on protoplanetary disk physics and chemistry. (2) Planetary atmospheres show rapidly varying X-ray components from charge exchange of heavy solar wind ions, electron bremsstrahlung continuum from ion-neutral interactions, and scattering and fluorescence of solar X-ray emission. IXO will produce a movie of these effects in Jupiter as the planet rotates and responds to solar flare/CME events. IXO study of the remarkable Martian X-ray exosphere will constrain the evaporation of planetary atmospheres. Three additional science programs are outlined: study of charge exchange processes in cometary comae; spectroscopy of diffuse heliospheric charge exchange X-rays previously attributed to the hot local interstellar medium; and measurements of flaring in stars hosting extrasolar planets in the Habitable Zone to evaluate atmospheric evaporation.

Feigelson, Eric; Elsner, R.; Glassgold, A.; Guedel, M.; Montmerle, T.; Wargelin, B.; Wolk, S.

2009-01-01

392

Soft X-ray response of a CCD with a grating spectrometer  

Microsoft Academic Search

We calibrate the X-ray imaging spectrometers, which are CCD cameras installed on the ASTRO-E satellite, by using dispersed continuous soft X-rays from a grating spectrometer. We obtained the signal-pulse height and energy-resolution as a function of X-ray energies continuously. However, the wings of the line spread function of the grating distorts the center of the signal-pulse height derived by a

M. Shouho; K. Katayama; H. Katayama; T. Kohmura; H. Tsunemi; S. Kitamoto; K. Hayashida; E. Miyata; K. Hashimotodani; K. Yoshita; K. Koyama; G. Ricker; M. W. Bautz; R. Foster; S. Kissel

1999-01-01

393

Solar X-Ray Spectroscopy and Optical Line Polarimetry.  

National Technical Information Service (NTIS)

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

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

1973-01-01

394

Si(Li) X-ray astronomical spectroscopy  

NASA Technical Reports Server (NTRS)

The general considerations involved in the choice of Si(Li) as a non-dispersive spectrometer for X-ray astronomy are discussed. In particular, its adaptation to HEAO-B is described as an example of the space-borne application of Si(Li) technology.

Holt, S. S.

1975-01-01

395

HIGH RESOLUTION X-RAY SPECTROSCOPY WITH A MICROCALORIMETER  

Microsoft Academic Search

Energy-dispersive spectrometry (EDS) is often the preferred choice for X-ray microanalysis, but there are still many disadvantages associated with EDS, the most significant of which is the relatively poor energy resolution, which limits detection sensitivity and the ability to distinguish among closely spaced spectral features, limiting even qualitative analysis. A new type of EDS detector that operates on the principle

JOHANNES NORRELL; IAN ANDERSON

396

HARD X-RAY AND MICROWAVE OBSERVATIONS OF MICROFLARES Jiong Qiu,1, 2  

E-print Network

V and microwave emission at around 10 GHz. Spectral analysis in these two wavelengths corroborates the nonthermalHARD X-RAY AND MICROWAVE OBSERVATIONS OF MICROFLARES Jiong Qiu,1, 2 Chang Liu,2 Dale E. Gary,2 Gelu, we study solar microflares using the coordinated hard X-ray and microwave observations obtained

Qiu, Jiong

397

Analysis of the Deformation Behavior of Magnesium-Rare Earth Alloys Mg-2 pct Mn-1 pct Rare Earth and Mg-5 pct Y-4 pct Rare Earth by In Situ Energy-Dispersive X-ray Synchrotron Diffraction and Elasto-Plastic Self-Consistent Modeling  

NASA Astrophysics Data System (ADS)

The deformation behavior of the Mg-RE alloys ME21 and WE54 was investigated. Although both alloys contain rare earth elements, which alter and weaken the texture, the flow curves of the alloys deviate significantly, especially in uniaxial compression test. Apart from the higher strength of the WE54 alloy, the compression flow curve does not exhibit the typical sigmoidal shape, which is associated with tension twinning. However, optical microscopy, X-ray texture measurements, and EBSD analysis reveal the activity of tension twinning. The combination of in situ energy-dispersive X-ray synchrotron diffraction and EPSC modeling was used to analyze these differences. The investigation reveals that twin propagation is decelerated in the WE54 alloy, which requires a change of the twinning scheme from the `finite initial fraction' to the `continuity' assumption. Furthermore, an enhanced activity of the < c+ a> pyramidal slip system was observed in case of the WE54 alloy.

Lentz, Martin; Klaus, Manuela; Coelho, Rodrigo S.; Schaefer, Nobert; Schmack, Florian; Reimers, Walter; Clausen, Bjørn

2014-11-01

398

Analysis of the Deformation Behavior of Magnesium-Rare Earth Alloys Mg-2 pct Mn-1 pct Rare Earth and Mg-5 pct Y-4 pct Rare Earth by In Situ Energy-Dispersive X-ray Synchrotron Diffraction and Elasto-Plastic Self-Consistent Modeling  

NASA Astrophysics Data System (ADS)

The deformation behavior of the Mg-RE alloys ME21 and WE54 was investigated. Although both alloys contain rare earth elements, which alter and weaken the texture, the flow curves of the alloys deviate significantly, especially in uniaxial compression test. Apart from the higher strength of the WE54 alloy, the compression flow curve does not exhibit the typical sigmoidal shape, which is associated with tension twinning. However, optical microscopy, X-ray texture measurements, and EBSD analysis reveal the activity of tension twinning. The combination of in situ energy-dispersive X-ray synchrotron diffraction and EPSC modeling was used to analyze these differences. The investigation reveals that twin propagation is decelerated in the WE54 alloy, which requires a change of the twinning scheme from the `finite initial fraction' to the `continuity' assumption. Furthermore, an enhanced activity of the pyramidal slip system was observed in case of the WE54 alloy.

Lentz, Martin; Klaus, Manuela; Coelho, Rodrigo S.; Schaefer, Nobert; Schmack, Florian; Reimers, Walter; Clausen, Bjørn

2014-09-01

399

Advanced X-ray Astrophysics Facility (AXAF) science instrumentation  

NASA Technical Reports Server (NTRS)

AXAF is to be equipped with a high performance X-ray telescope for the conduction of detailed astrophysics research. The observatory is to be serviced by the Space Station or the Shuttle, depending on capabilities during the AXAF operational period. The AXAF is to utilize the wavelength band from 1.2 A to 120 A. Attention is given to the AXAF science team, the AXAF observatory characteristics, the AXAF science instrument definition program, the Advanced Charge Coupled Device (CCD) Imaging Spectrometer (ACIS), the High Resolution Camera (HRC), the Bragg Crystal Spectrometer (BCS), the X-ray Spectrometer (XRS), the transmission gratings, and the program schedule.

Dailey, C. C.; Cumings, N. P.; Winkler, C. E.

1985-01-01

400

Minerals Arranged by X-Ray Powder Diffraction  

NSDL National Science Digital Library

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

401

Three-dimensional manipulation of electron beam phase space for seeding soft x-ray free-electron lasers  

NASA Astrophysics Data System (ADS)

In this paper, a simple technique is proposed to induce strong density modulation into the electron beam with small energy modulation. By using the combination of a transversely dispersed electron beam and a wave-front tilted seed laser, three-dimensional manipulation of the electron beam phase space can be utilized to significantly enhance the microbunching of seeded free-electron laser schemes, which will improve the performance and extend the short-wavelength range of a single-stage seeded free-electron laser. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in a soft x-ray free-electron laser.

Feng, Chao; Zhang, Tong; Deng, Haixiao; Zhao, Zhentang

2014-07-01

402

Three-dimensional manipulation of electron beam phase space for seeding soft x-ray free-electron lasers  

E-print Network

In this letter, a simple technique is proposed to induce strong density modulation into the electron beam with small energy modulation. By using the combination of a transversely dispersed electron beam and a wave-front tilted seed laser, three-dimensional manipulation of the electron beam phase space can be utilized to significantly enhance the micro-bunching of seeded free-electron laser schemes, which will improve the performance and extend the short-wavelength range of a single-stage seeded free-electron laser. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in a soft x-ray free-electron laser.

Feng, Chao; Deng, Haixiao; Zhao, Zhentang

2014-01-01

403

Recent advances in X-ray photoconductors for direct conversion X-ray image detectors  

Microsoft Academic Search

Recent research on flat panel X-ray image detectors has shown their potential for replacing existing X-ray film\\/screen cassettes and capturing X-ray images electronically, thus enabling the clinical transition to digital radiography. The present work examines the imaging properties of a number of potential X-ray photoconductors for these new X-ray image detectors. The X-ray sensitivity is discussed in terms of the

S. O. Kasap; M. Zahangir Kabir; J. A. Rowlands

2006-01-01

404

X-Ray Structure determination of the Glycine Cleavage System Protein H of Mycobacterium tuberculosis Using An Inverse Compton Synchrotron X-Ray Source  

PubMed Central

Structural genomics discovery projects require ready access to both X-ray and NMR instrumentation which support the collection of experimental data needed to solve large numbers of novel protein structures. The most productive X-ray crystal structure determination laboratories make extensive frequent use of tunable synchrotron X-ray light to solve novel structures by anomalous diffraction methods. This requires that frozen cryo-protected crystals be shipped to large government-run synchrotron facilities for data collection. In an effort to eliminate the need to ship crystals for data collection, we have developed the first laboratory-scale synchrotron light source capable of performing many of the state-of-the-art synchrotron applications in X-ray science. This Compact Light Source is a first-in-class device that uses inverse Compton scattering to generate X-rays of sufficient flux, tunable wavelength and beam size to allow high-resolution X-ray diffraction data collection from protein crystals. We report on benchmarking tests of X-ray diffraction data collection with hen egg white lysozyme, and the successful high-resolution X-ray structure determination of the Glycine cleavage system protein H from Mycobacterium tuberculosis using diffraction data collected with the Compact Light Source X-ray beam. PMID:20364333

Abendroth, Jan; McCormick, Michael S.; Edwards, Thomas E.; Staker, Bart; Loewen, Roderick; Gifford, Martin; Rifkin, Jeff; Mayer, Chad; Guo, Wenjin; Zhang, Yang; Myler, Peter; Kelley, Angela; Analau, Erwin; Hewitt, Stephen Nakazawa; Napuli, Alberto J.; Kuhn, Peter; Ruth, Ronald D.; Stewart, Lance J.

2010-01-01

405

Hard X-ray Optics Technology Development for Astronomy at the Marshall Space Flight Center  

NASA Technical Reports Server (NTRS)

Grazing-incidence telescopes based on Wolter 1 geometry have delivered impressive advances in astrophysics at soft-x-ray wavelengths, while the hard xray region remains relatively unexplored at fine angular resolution and high sensitivities. The ability to perform ground-breaking science in the hard-x-ray energy range had been the motivation for technology developments aimed at fabricating low-cost, light-weight, high-quality x-ray mirrors. Grazing-incidence x-ray optics for high-energy astrophysical applications is being developed at MSFC using the electroform-nickel replication process.

Gubarev, Mikhail; Ramsey, Brian; Kilaru, Kiranmayee

2009-01-01

406

Growth of K(Cl, Br) crystals from aqueous solutions in an X-ray field  

SciTech Connect

The influence of X-rays of different wavelength on the degree of structural quality of K(Cl, Br) crystals of mixed composition grown from aqueous solutions is considered. It is found by the methods of chemical etching, X-ray analysis, pycnometric density, and atomic-force microscopy that X-ray irradiation leads to the formation of crystals with a more perfect substructure and surface morphology and a decrease of the dislocation density and concentration of pores and cavities containing the mother liquor. It is shown that X-ray irradiation can promote preferential incorporation of less electronegative components into the crystal lattice of a solid solution.

Anishchik, V. M., E-mail: Anishchik@bsu.by [Belarussian State University (Belarus); Val'ko, N. G., E-mail: N.Valko@grsu.by; Voina, V. V.; Vorontsov, A. S. [Grodno State University (Belarus)

2008-07-15

407

Harmonic lasing of x-ray free electron laser: on the way to smaller and cheaper  

E-print Network

By utilizing higher harmonics of undulator radiation, harmonic lasing is helpful in the development of compact x-ray free electron lasers (FELs), i.e. reducing its costs and sizes. Harmonic lasing of FELs have been experimentally demonstrated in the low-gain FEL oscillators from terahertz, infrared to ultraviolet spectral range. Based on the current status and future directions of short-wavelength FELs in the worldwide, this paper reviews the progresses on harmonic lasing of x-ray FELs, mainly concentrating on the recently proposed harmonic lasing of x-ray FEL oscillators and further ideas on harmonic lasing of single pass x-ray FEL amplifiers.

Deng, Haixiao

2012-01-01

408

Background-reducing X-ray multilayer mirror  

DOEpatents

Background-reducing x-ray multilayer mirror. A multiple-layer "wavetrap" deposited over the surface of a layered, synthetic-microstructure soft x-ray mirror optimized for reflectivity at chosen wavelengths is disclosed for reducing the reflectivity of undesired, longer wavelength incident radiation incident thereon. In three separate mirror designs employing an alternating molybdenum and silicon layered, mirrored structure overlaid by two layers of a molybdenum/silicon pair anti-reflection coating, reflectivities of near normal incidence 133, 171, and 186 .ANG. wavelengths have been optimized, while that at 304 .ANG. has been minimized. The optimization process involves the choice of materials, the composition of the layer/pairs as well as the number thereof, and the distance therebetween for the mirror, and the simultaneous choice of materials, the composition of the layer/pairs, and their number and distance for the "wavetrap."

Bloch, Jeffrey J. (Los Alamos, NM); Roussel-Dupre', Diane (Los Alamos, NM); Smith, Barham W. (Los Alamos, NM)

1992-01-01

409

Microgap x-ray detector  

DOEpatents

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

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

1994-01-01

410

Microgap x-ray detector  

DOEpatents

An x-ray detector is disclosed which provides for the conversion of x-ray photons into photoelectrons and subsequent amplification of these photoelectrons through the generation of electron avalanches in a thin gas-filled region subject to a high electric potential. The detector comprises a cathode (photocathode) and an anode separated by the thin, gas-filled region. The cathode may comprise a substrate, such a beryllium, coated with a layer of high atomic number material, such as gold, while the anode can be a single conducting plane of material, such as gold, or a plane of resistive material, such as chromium/silicon monoxide, or multiple areas of conductive or resistive material, mounted on a substrate composed of glass, plastic or ceramic. The charge collected from each electron avalanche by the anode is passed through processing electronics to a point of use, such as an oscilloscope. 3 figures.

Wuest, C.R.; Bionta, R.M.; Ables, E.

1994-05-03

411

Overview of the Chandra X-Ray Observatory Facility  

NASA Technical Reports Server (NTRS)

The Chandra X-Ray Observatory (originally called the Advanced X-Ray Astrophysics Facility - AXAF) is the X-Ray component of NASA's "Great Observatory" Program. Chandra is a NASA facility that provides scientific data to the international astronomical community in response to scientific proposals for its use. The Observatory is the product of the efforts of many organizations in the United States and Europe. The Great Observatories also include the Hubble Space Telescope for space-based observations of astronomical objects primarily in the visible portion of the electromagnetic spectrum, the now defunct Compton Gamma- Ray Observatory that was designed to observe gamma-ray emission from astronomical objects, and the soon-to-be-launched Space Infrared Telescope Facility (SIRTF). The Chandra X-Ray Observatory (hereafter CXO) is sensitive to X-rays in the energy range from below 0.1 to above 10.0 keV corresponding to wavelengths from 12 to 0.12 nanometers. The relationship among the various parts of the electromagnetic spectrum, sorted by characteristic temperature and the corresponding wavelength, is illustrated. The German physicist Wilhelm Roentgen discovered what he thought was a new form of radiation in 1895. He called it X-radiation to summarize its properties. The radiation had the ability to pass through many materials that easily absorb visible light and to free electrons from atoms. We now know that X-rays are nothing more than light (electromagnetic radiation) but at high energies. Light has been given many names: radio waves, microwaves, infrared, visible, ultraviolet, X-ray and gamma radiation are all different forms. Radio waves are composed of low energy particles of light (photons). Optical photons - the only photons perceived by the human eye - are a million times more energetic than the typical radio photon, whereas the energies of X-ray photons range from hundreds to thousands of times higher than that of optical photons. Very low temperature systems (hundreds of degrees below zero Celsius) produce low energy radio and microwave photons, whereas cool bodies like our own (about 30 degrees Celsius) produce infrared radiation. Very high temperatures (millions of degrees Celsius) are one way of producing X-rays.

Weisskopf, M. C.; Six, N. Frank (Technical Monitor)

2002-01-01

412

Spatially resolved X-ray excited optical luminescence  

NASA Astrophysics Data System (ADS)

Spatially resolved luminescence distributions in semiconductor heterostructures were investigated by core level excitation using hard X-ray (sub-) microbeams. Compact and mobile XEOL instruments have been developed and well adapted on the hard X-ray beamline ID22 of the European Synchrotron Radiation Facility for different wavelength collection ranges: UV-VIS and NIR. Linked by multimode optical fibers, their special designs provide precise scanning microscopy and allow easy access for multiple detection modes. Based on the hard X-ray microprobe station of ID22, details of the equipments, spectral data and representative examples are briefly described. Data collections from InAs and InGaN quantum heterostructures support the excellent performance of the optical devices.

Martínez-Criado, G.; Alén, B.; Sans, J. A.; Homs, A.; Kieffer, I.; Tucoulou, R.; Cloetens, P.; Segura-Ruiz, J.; Susini, J.; Yoo, J.; Yi, G.

2012-08-01

413

On the possibility of X-ray refractive radiography using multilayer mirrors with resonant absorption  

Microsoft Academic Search

An X-ray multilayer mirror, with a nonperiodic structure specially designed to produce resonant absorption at a definite angle of incidence, may be used as a dispersive element for refractive X-ray radiography instead of a standard crystal analyzer. In this scheme the direct beam can be significantly suppressed. Numerical simulation of the imaging process, based on the experimental data obtained with

V. V. Protopopov

2000-01-01

414

Chandra X-ray Imaging and Spectroscopy of the M87 Jet and Nucleus  

E-print Network

We report X-ray imaging - spectroscopy of the jet of M87 at sub arc second resolution with the Chandra X-ray Observatory. The galaxy nucleus and all the knots seen at radio and optical wavelengths, as far from the nucleus as knot C, are detected in the X-ray observations. There is a strong trend for the ratio of X-ray to radio, or optical, flux to decline with increasing distance from the nucleus. At least three knots are displaced from their radio/optical counterparts, being tens of pc closer to the nucleus at X-ray than at radio or optical wavelengths. The X-ray spectra of the nucleus and knots are well described by power laws absorbed by cold gas, with only the unresolved nucleus exhibiting intrinsic absorption. In view of the similar spectra of the nucleus and jet knots, and the high X-ray flux of the knots closest to the nucleus, we suggest that the X-ray emission coincident with the nucleus may actually originate from the pc - or sub-pc - scale jet rather than the accretion disk. Arguments are given that the X-ray emission process is unlikely to be inverse Compton scattering. Instead, we favor synchrotron radiation. Plotted as $\

A. S. Wilson; Y. Yang

2001-12-05

415

Characterization of new hard X-ray cataclysmic variables  

NASA Astrophysics Data System (ADS)

Aims: We aim at characterizing a sample of nine new hard X-ray selected cataclysmic variable (CVs), to unambiguously identify them as magnetic systems of the intermediate polar (IP) type. Methods: We performed detailed timing and spectral analysis by using X-ray, and simultaneous UV and optical data collected by XMM-Newton, complemented with hard X-ray data provided by INTEGRAL and Swift. The pulse arrival time were used to estimate the orbital periods. The broad band X-ray spectra were fitted using composite models consisting of different absorbing columns and emission components. Results: Strong X-ray pulses at the white dwarf (WD) spin period are detected and found to decrease with energy. Most sources are spin-dominated systems in the X-rays, though four are beat dominated at optical wavelengths. We estimated the orbital period in all system (except for IGR J16500-3307), providing the first estimate for IGR J08390-4833, IGR J18308-1232, and IGR J18173-2509. All X-ray spectra are multi-temperature. V2069 Cyg and RX J0636+3535 posses a soft X-ray optically thick component at kT ~ 80 eV. An intense K? Fe line at 6.4 keV is detected in all sources. An absorption edge at 0.76 keV from OVII is detected in IGR J08390-4833. The WD masses and lower limits to the accretion rates are also estimated. Conclusions: We found all sources to be IPs. IGR J08390-4833, V2069 Cyg, and IGR J16500-3307 are pure disc accretors, while IGR J18308-1232, IGR J1509-6649, IGR J17195-4100, and RX J0636+3535 display a disc-overflow accretion mode. All sources show a temperature gradient in the post-shock regions and a highly absorbed emission from material located in the pre-shock flow which is also responsible for the X-ray pulsations. Reflection at the WD surface is likely the origin of the fluorescent iron line. There is an increasing evidence for the presence of a warm absorber in IPs, a feature that needs future exploration. The addition of two systems to the subgroup of soft X-ray IPs confirms a relatively large (~30%) incidence. Based on observations obtained with XMM-Newton and INTEGRAL, ESA science missions with instruments and contributions directly funded by ESA Member States; and Swift, a NASA science mission with Italian participation.

Bernardini, F.; de Martino, D.; Falanga, M.; Mukai, K.; Matt, G.; Bonnet-Bidaud, J.-M.; Masetti, N.; Mouchet, M.

2012-06-01

416

Soft X-ray techniques to study mesoscale magnetism  

SciTech Connect

Heterogeneity in magnetization (M) is ubiquitous in modern systems. Even in nominally homogeneous materials, domains or pinning centers typically mediate magnetization reversal. Fundamental lengths determining M structure include the domain wall width and the exchange stiffness length, typically in the 4-400 nm range. Chemical heterogeneity (phase separation, polycrystalline microstructure, lithographic or other patterning, etc.) with length scales from nanometers to microns is often introduced to influence magnetic properties. With 1-2 nm wavelengths {lambda}, soft x-rays in principle can resolve structure down to {lambda}/2, and are well suited to study these mesoscopic length scales [1, 2]. This article highlights recent advances in resonant soft x-ray methods to resolve lateral magnetic structure [3], and discusses some of their relative merits and limitations. Only techniques detecting x-ray photons (rather than photo-electrons) are considered [4], since they are compatible with strong applied fields to probe relatively deeply into samples. The magneto-optical (MO) effects discovered by Faraday and Kerr were observed in the x-ray range over a century later, first at ''hard'' wavelengths in diffraction experiments probing interatomic magnetic structure [5]. In the soft x-ray range, magnetic linear [6] and circular [7] dichroism spectroscopies first developed that average over lateral magnetic structure. These large resonant MO effects enable different approaches to study magnetic structure or heterogeneity that can be categorized as microscopy or scattering [1]. Direct images of magnetic structure result from photo-emission electron microscopes [4, 8] and zone-plate microscopes [9, 10]. Scattering techniques extended into the soft x-ray include familiar specular reflection that laterally averages over structure but can provide depth-resolved information, and diffuse scattering and diffraction that provide direct information about lateral magnetic structure. Scattering techniques are further classified as partially for fully coherent according to the extent of transverse coherence of the incident beam.

Kortright, Jeffrey B.

2003-06-26

417

X-ray lasers and high-density plasma  

SciTech Connect

The improved reliability, high brightness, and short wavelength of x-ray lasers make them ideally suited for studying large, high-density plasmas of interest to the laser-fusion research community. We have been developing the neonlike yttrium x-ray laser as a probe, together with the necessary multilayer mirrors and beam splitters, to image plasmas produced at the Nova laser facility and to measure electron density. With its short-wavelength (15.5-nm) light, we can use the yttrium x-ray laser to probe plasma densities up to 10{sup 23} cm{sup {minus}3}. At the highest magnification (30?), the spatial resolution of our imaging system is better than 1 {mu}m. Using the technique of moire deflectometry, we have measured density gradients of plasmas. Using the technique of interferometry, we have probed 3-mm-long plasmas with electron densities up to 3? 10{sup 21} cm{sup {minus}3}. Temporal blurring of plasma images remains the main limitation of our approach. Thus, we are continuing to improve our theoretical and experimental understanding of laboratory x-ray lasers. We are currently working on techniques to reduce the blurring of images by shortening the x-ray laser pulse to durations approaching about 20 ps. In the future, this important research tool can be applied to study high-density plasmas produced at the proposed National Ignition Facility. Other important applications of the x-ray laser include biological imaging of whole, live cells and other structures at resolutions superior to those obtainable by conventional optical microscopy.

NONE

1995-03-01

418

Wavefront metrology measurements at SACLA by means of X-ray grating interferometry.  

PubMed

The knowledge of the X-ray wavefront is of importance for many experiments at synchrotron sources and hard X-ray free-electron lasers. We will report on metrology measurements performed at the SACLA X-ray Free Electron Laser by means of grating interferometry which allows for an at-wavelength, in-situ, and single-shot characterization of the X-ray wavefront. At SACLA the grating interferometry technique was used for the study of the X-ray optics installed upstream of the end station, two off-set mirror systems and a double crystal monochromator. The excellent quality of the optical components was confirmed by the experimental results. Consequently grating interferometry presents the ability to support further technical progresses in X-ray mirror manufacturing and mounting. PMID:24787789

Kayser, Yves; Rutishauser, Simon; Katayama, Tetsuo; Ohashi, Haruhiko; Kameshima, Takashi; Flechsig, Uwe; Yabashi, Makina; David, Christian

2014-04-21

419

Producing X-rays at the APS  

SciTech Connect

An introduction and overview of the Advanced Photon Source at Argonne National Laboratory, the technology that produces the brightest X-ray beams in the Western Hemisphere, and the research carried out by scientists using those X-rays.

None

2011-01-01

420

X-ray Photography: Inner Beauty  

NSDL National Science Digital Library

This article from TIME features Nick Veasey, an x-ray photographer who combines art and science through his photographs. The short article explains how Veasey started his work and includes a link to more x-ray photographs.

2009-10-15

421

Computed tomographic x-ray velocimetry (CTXV)  

E-print Network

Computed tomographic x-ray velocimetry (CTXV) Australia n China n India n Italy n Malaysia n South of Engineering have developed a new computed tomographic X-ray velocimetry technique for simultaneous 3D

Albrecht, David

422

Advances in transmission x-ray optics  

SciTech Connect

Recent developments in x-ray optics are reviewed. Specific advances in coded aperture imaging, zone plate lens fabrication, time and space resolved spectroscopy, and CCD x-ray detection are discussed.

Ceglio, N.M.

1983-01-01

423

Spectral analysis of X-ray binaries  

E-print Network

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

Fridriksson, Joel Karl

2011-01-01

424

Tracing Ambient Air Geochemistry using a Modified X-Ray Fluorescence Filter Method  

NASA Astrophysics Data System (ADS)

Modifications of x-ray fluorescence counting procedures enable tracing of aerosol dispersals related to weather fronts and local weather phenomena. Improved X-ray fluorescence methods for bulk aerosols deposited under positive air pressure conditions onto Millipore filters at 80 liters/hour enable the tracing of geological samples in periods down to one hour. Vacuum-plating aliquots of USGS standards onto 0.2 micron polycarbonate and quartz Millipore filters create standards with a shelf life of several months. The analytical system permits detection of light oxides, such as silica to 10 ppm, and heavy elements, such as iron to 0.5 ppm. These collections allow discriminations to be drawn between dominantly geological, silica-enriched air mass and dominantly iron-enriched air of possible industrial origin. These ambient air collections at 120 feet elevation at City College are used to create possible distinctions in air masses related to points of origin. Splits of aerosol examined by neutron activation and coupled plasma emission spectroscopy agree with x-ray fluorescence methods to within analytical error. Aerosol flux conditions are monitored for speciation using direct examination by scanning electron microscopy with energy dispersive analytical capability plus aerosol physical properties by sun photometry. The latter provides bulk optical transmission at six major wavelengths and estimates for bulk aerosol size properties. Preliminary data show positive photometry links with iron-aerosols with a correlation coefficient with southwesterly wind-driven conditions of seventy percent over a four hour monitoring period. Aerosol flux comparisons with heavy metal populations, Ba, Rb, Zr, La show uniform distributions with iron- and silica-enriched populations indicating a pervasive background condition in the ambient air mass over New York City.

Steiner, J. C.; Rudolph, E.; Wrice, T.

2002-12-01

425

Optics-free x-ray FEL oscillator  

SciTech Connect

There is a need for an Optics-Free FEL Oscillators (OFFELO) to further the advantages of free-electron lasers and turning them in fully coherent light sources. While SASE (Self-Amplified Spontaneous Emission) FELs demonstrated the capability of providing very high gain and short pulses of radiation and scalability to the X-ray range, the spectra of SASE FELs remains rather wide ({approx}0.5%-1%) compared with typical short wavelengths FEL-oscillators (0.01%-0.0003% in OK-4 FEL). Absence of good optics in VUV and X-ray ranges makes traditional oscillator schemes with very high average and peak spectral brightness either very complex or, strictly speaking, impossible. In this paper, we discuss lattice of the X-ray optics-free FEL oscillator and present results of initial computer simulations of the feedback process and the evolution of FEL spectrum in X-ray OFFELO. We also discuss main limiting factors and feasibility of X-ray OFFELO.

Litvinenko, V.N.; Hao, Y.; Kayran, D.; Trbojevic, D.

2011-03-28

426

The History of X-ray Free-Electron Lasers  

SciTech Connect

The successful lasing at the SLAC National Accelerator Laboratory of the Linear Coherent Light Source (LCLS), the first X-ray free-electron laser (X-ray FEL), in the wavelength range 1.5 to 15 {angstrom}, pulse duration of 60 to few femtoseconds, number of coherent photons per pulse from 10{sup 13} to 10{sup 11}, is a landmark event in the development of coherent electromagnetic radiation sources. Until now electrons traversing an undulator magnet in a synchrotron radiation storage ring provided the best X-ray sources. The LCLS has set a new standard, with a peak X-ray brightness higher by ten orders of magnitudes and pulse duration shorter by three orders of magnitudes. LCLS opens a new window in the exploration of matter at the atomic and molecular scales of length and time. Taking a motion picture of chemical processes in a few femtoseconds or less, unraveling the structure and dynamics of complex molecular systems, like proteins, are some of the exciting experiments made possible by LCLS and the other X-ray FELs now being built in Europe and Asia. In this paper, we describe the history of the many theoretical, experimental and technological discoveries and innovations, starting from the 1960s and 1970s, leading to the development of LCLS.

Pellegrini, C.; /UCLA /SLAC; ,

2012-06-28

427

Stellar winds in binary X-ray systems  

NASA Technical Reports Server (NTRS)

It is thought that accretion from a strong stellar wind by a compact object may be responsible for the X-ray emission from binary systems containing a massive early-type primary. To investigate the effect of X-ray heating and ionization on the mass transfer process in systems of this type, an idealized model is constructed for the flow of a radiation-driven wind in the presence of an X-ray source of specified luminosity, L sub x. It is noted that for low values of L sub x, X-ray photoionization gives rise to additional ions having spectral lines with wavelengths situated near the peak of the primary continuum flux distribution. As a consequence, the radiation force acting on the gas increases in relation to its value in the absence of X-rays, and the wind is accelerated to higher velocities. As L sub x is increased, the degree of ionization of the wind increases, and the magnitude of the radiation force is diminished in comparison with the case in which L sub x = 0. This reduction leads at first to a decrease in the wind velocity and ultimately (for L sub x sufficiently large) to the termination of radiatively driven mass loss.

Macgregor, K. B.; Vitello, P. A. J.

1982-01-01

428

Nondestructive analysis of single crystals of selenide spinels by X-ray spectrometry techniques  

Microsoft Academic Search

The paper presents possibilities and difficulties in nondestructive analysis of small multielement single crystals performed\\u000a by means of X-ray spectrometry techniques: micro-X-ray fluorescence spectrometry (?-XRF), energy-dispersive electron probe\\u000a microanalysis (ED-EPMA), and X-ray photoelectron spectroscopy (XPS). The capability of the X-ray spectroscopy techniques in\\u000a elemental analysis is demonstrated with the single crystals of selenide spinels of the general formula M\\u000a x

E. Malicka; R. Sitko; B. Zawisza; J. Heimann; D. Kajewski; A. Kita

2011-01-01

429

Phase-sensitive X-ray imager  

DOEpatents

X-ray phase sensitive wave-front sensor techniques are detailed that are capable of measuring the entire two-dimensional x-ray electric field, both the amplitude and phase, with a single measurement. These Hartmann sensing and 2-D Shear interferometry wave-front sensors do not require a temporally coherent source and are therefore compatible with x-ray tubes and also with laser-produced or x-pinch x-ray sources.

Baker, Kevin Louis

2013-01-08

430

The Electromagnetic Spectrum: X-Rays  

NSDL National Science Digital Library

This site provided by NASA contains an introduction to X-rays and their uses in medicine and astronomy. Descriptions of the first X-ray observations, how they are used to visualize parts of the body, and results from X-ray astronomy are provided. The site contains striking astronomical images made with X-rays. Also provided are links to similar sites on the other electromagnetic spectrum regions.

2006-11-25

431

X-rays from old star clusters  

E-print Network

A brief overview is given of X-ray observations of old clusters. Most X-ray sources in old open clusters are interacting binaries, formed via evolution of a primordial binary, and emitting X-rays because of magnetic activity; however, a sizable fraction of the cluster sources is not well understood, including some of the most luminous ones. Globular clusters appear to contain fewer magnetically active X-ray sources than expected if one scales from old open clusters by mass.

Frank Verbunt

1999-07-15

432

X-ray Observations of Eight Young Open Star Clusters: I. Membership and X-ray Luminosity  

NASA Astrophysics Data System (ADS)

We present a detailed investigation of X-ray source contents of eight young open clusters with ages between 4 to 46 Myr using archival X-ray data from XMM-Newton. The probable cluster memberships of the X-ray sources have been established on the basis of multi-wavelength archival data, and samples of 152 pre-main sequence (PMS) low mass (<2 M ?), 36 intermediate mass (2-10 M ?) and 16 massive (>10 M ?) stars have been generated. X-ray spectral analyses of high mass stars reveal the presence of high temperature plasma with temperature <2 keV, and mean L X/ L bol of 10 - 6.9. In the case of PMS low mass stars, the plasma temperatures have been found to be in the range of 0.2 keV to 3 keV with a median value of ~1.3 keV, with no significant difference in plasma temperatures during their evolution from 4 to 46 Myr. The X-ray luminosity distributions of the PMS low mass stars have been found to be similar in the young star clusters under study. This may suggest a nearly uniform X-ray activity in the PMS low mass stars of ages ~4-14 Myr. These observed values of L X/ L bol are found to have a mean value of 10- 3.6±0.4, which is below the X-ray saturation level. The L X/ L bol values for the PMS low mass stars are well correlated with their bolometric luminosities, that implies its dependence on the internal structure of the low mass stars. The difference between the X-ray luminosity distributions of the intermediate mass stars and the PMS low mass stars has not been found to be statistically significant. Their L X/ L bol values, however have been found to be significantly different from each other with a confidence level greater than 99.999% and the strength of X-ray activity in the intermediate mass stars is found to be lower compared to the low mass stars. However, the possibility of X-ray emission from the intermediate mass stars due to a low mass star in close proximity of the intermediate mass star can not be ruled out.

Bhatt, Himali; Pandey, J. C.; Singh, K. P.; Sagar, Ram; Kumar, Brijesh

2013-12-01

433

Cataclysmic variables as probes of x-ray properties of interstellar grains  

SciTech Connect

Interstellar-grain properties have previously been probed at wavelengths ranging from the infrared to the ultraviolet. Recent work by other authors has shown that we may also observe the effects of scattering by such grains at x-ray wavelengths. In this paper we suggest that investigations of the x-ray properties of interstellar grains may profitably be conducted in sight lines to variable sources. Particular emphasis is given in this context to cataclysmic variables and related objects.

Bode, M.F.; Evans, A.; Norwell, G.A.

1983-01-01

434

Are X-Rays Safe during Pregnancy?  

MedlinePLUS

... And most of these deformities are minor, like skin tags or an extra finger or toe. Could I have another test instead of an X-ray? You might be able to have an ultrasound exam instead of an X-ray. Ultrasound, which is also called sonography, is the best alternative to an X-ray. ...