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1

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

2

Apollo 15 Geochemical X-ray Fluorescence Experiment: Preliminary Report  

Microsoft Academic Search

Although only part of the information from the x-ray fluorescence geochemical experiment has been analyzed, it is clear that the experiment was highly successful. Significant compositional differences among and possibly within the maria and highlands have been detected. When viewed in the light of analyzed lunar rocks and soil samples, and the data from other lunar orbital experiments (in particular,

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

1972-01-01

3

The Apollo 15 X-ray fluorescence experiment  

NASA Technical Reports Server (NTRS)

The CSM spectrometric data on the lunar surface with respect to its chemical composition are presented for Al, Mg, and Si as Al/Si and Mg/Si ratios for the various features overflow by the spacecraft. The lunar surface measurements involved observations of the intensity and characteristic energy distribution of the secondary or fluorescent X-rays produced by the interaction of solar X-rays with the lunar surface. The results showed that the highlands and maria are chemically different, with the highlands having considerably more Al and less Mg than the maria. The mare-highland contact is quite sharp and puts a limit on the amount of horizontal transport of material. The X-ray data suggest that the dominant rock type of the lunar highlands is a plagioclase-rich pyroxene bearing rock, probably anorthositic gabbro or feldspathic basalt. Thus the moon appears to have a widespread differentiated crust (the highlands) systematically richer in Al and lower in Mg than the maria. This crust is pre-mare and may represent the first major internal differentiation of the moon.

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

1972-01-01

4

Apollo 16 geochemical X-ray fluorescence experiment: Preliminary report  

NASA Technical Reports Server (NTRS)

The lunar surface was mapped with respect to Mg, Al, and Si, as Al/Si and Mg/Si ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The Al/Si and Mg/Si chemical ratios correspond to that for anorthositic gabbro through gabbroic anorthosites or feldspathic basalts. The X-ray results suggest the occurrence of this premare crust or material similar to it as the Descartes landing site.

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

1972-01-01

5

Apollo 16 Geochemical X-ray Fluorescence Experiment: Preliminary Report.  

PubMed

The lunar surface was mapped with respect to magnesium, aluminum, and silicon as aluminum/ silicon and magnesium/ silicon intensity ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide new data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The aluminum/ silicon and magnesium/ silicon concentration ratios correspond to those for anorthositic gabbros through gabbroic anorthosites or feldspathic basalts. The x-ray results suggest the occurrence of this premare crust or material similar to it at the Descartes landing site. PMID:17815621

Adler, I; Trombka, J; Gerard, J; Lowman, P; Schmadebeck, R; Blodget, H; Eller, E; Yin, L; Lamothe, R; Osswald, G; Gorenstein, P; Bjorkholm, P; Gursky, H; Harris, B

1972-07-21

6

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

NASA Astrophysics Data System (ADS)

X-ray scattering may contribute significantly to the spectral background of X-ray fluorescence (XRF) spectra. Based on metrological measurements carried out with a scanning electron microscope (SEM) having attached a well characterised X-ray source (polychromatic X-ray tube) and a calibrated energy dispersive X-ray spectrometer (EDS) the accuracy of a physical model for X-ray scattering is systematically evaluated for representative samples. The knowledge of the X-ray spectrometer efficiency, but also of the spectrometer response functions makes it possible to define a physical spectral background of XRF spectra. Background subtraction relying on purely mathematical procedures is state-of-the-art. The results produced by the analytical model are at least as reliable as those obtained by Monte-Carlo simulations, even without considering the very challenging contribution of multiple scattering. Special attention has been paid to Compton broadening. Relevant applications of the implementation of the analytical model presented in this paper are the prediction of the limits of detection for particular cases or the determination of the transmission of X-ray polycapillary lenses.

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

2010-12-01

7

Laboratory experiment of particle size effect in X-ray fluorescence: implication to remote XRF results  

Microsoft Academic Search

Laboratory experiments have been performed to show that microscopic roughness in the uppermost layer of planetary surface results in remarkable alteration of intensities and spectral profiles of X-ray fluorescence, especially at large phase angles. In our studies, surface roughness was directly measured by laser microscopy. The measured surface profiles were smoothed and approximated into a single cyclic function of rectangular

T. Okada

2004-01-01

8

NEW CORRECTION PROCEDURE FOR X-RAY SPECTROSCOPIC FLUORESCENCE DATA: SIMULATIONS AND EXPERIMENT.  

SciTech Connect

X-ray fluorescence spectroscopy is a widely used method for determining the electronic configuration and local structure of dilute species with high sensitivity. In the dilute limit, and for thin films, the X-ray fluorescence signal is directly proportional to the atomic sub-shell absorption coefficient. However, for concentrated samples, the well-documented self-absorption effect often leads to the severe suppression of XANES (X-ray Absorption Near-Edge Structure) and EXAFS (Extended X-ray Absorption Fine-Structure) amplitudes. Thus to recover the real value of the sub-shell absorption coefficient, it is important to apply correction procedures to the measured fluorescence spectra. In this paper, we describe a new straightforward method to correct for self-absorption effects (the difference in the measured fluorescence signal compared to that of the true sub-shell photoabsorption coefficient) in XANES and EXAFS fluorescence measurements. Using a variety of sample and detector configurations, this method is used to extract the sub-shell absorption coefficient on elemental nickel and thick single-crystals of Gd{sub 3}Ga{sub 5}O{sub 12} and LaAlO{sub 3}.

ABLETT, J.M.; WOICIK, J.C.; KAO, C.C.

2004-08-02

9

The Viking X Ray Fluorescence Experiment: Analytical Methods and Early Results  

Microsoft Academic Search

Ten samples of the Martian regolith have been analyzed by the Viking lander X ray fluorescence spectrometers. Because of high-stability electronics, inclusion of calibration targets, and special data encoding within the instruments the quality of the analyses performed on Mars is closely equivalent to that attainable with the same instruments operated in the laboratory. Determination of absolute elemental concentrations requires

Benton C. Clark; A. K. Baird; Harry J. Rose; Priestley Toulmin; Ralph P. Christian; Warren C. Kelliher; Angelo J. Castro; Catherine D. Rowe; Klaus Keil; Gary R. Huss

1977-01-01

10

SAVLOC, computer program for automatic control and analysis of X-ray fluorescence experiments  

NASA Technical Reports Server (NTRS)

A program for a PDP-15 computer is presented which provides for control and analysis of trace element determinations by using X-ray fluorescence. The program simultaneously handles data accumulation for one sample and analysis of data from previous samples. Data accumulation consists of sample changing, timing, and data storage. Analysis requires the locating of peaks in X-ray spectra, determination of intensities of peaks, identification of origins of peaks, and determination of a real density of the element responsible for each peak. The program may be run in either a manual (supervised) mode or an automatic (unsupervised) mode.

Leonard, R. F.

1977-01-01

11

Chemical Environment Effects on K[beta]/K[alpha] Intensity Ratio: An X-Ray Fluorescence Experiment on Periodic Trends  

ERIC Educational Resources Information Center

X-ray fluorescence (XRF) data from an energy-dispersive XRF instrument were used to investigate the chlorine K[alpha] and K[beta] peaks in several group 1 salts. The ratio of the peak intensity is sensitive to the local chemical environment of the chlorine atoms studied in this experiment and it shows a periodic trend for these salts. (Contains 1…

Durham, Chaney R.; Chase, Jeffery M.; Nivens, Delana A.; Baird, William H.; Padgett, Clifford W.

2011-01-01

12

Measurements of K x-ray fluorescence parameters  

Microsoft Academic Search

A simple x-ray fluorescence experiment suitable for graduate and undergraduate laboratories is described. The experiment uses a NaI(Tl) x-ray spectrometer, a weak 57Co radioactive source (~105 Bq), and medium-Z targets of silver, cadmium, indium, and tin. The K x-ray fluorescence yield, omegak, and K x-ray production cross section, sigmak, are measured for these targets. Accurate results are achieved by adopting

A. S. Bennal; P. D. Shidling; N. M. Badiger; S. R. Thontadarya; B. Hanumaiah

2005-01-01

13

Confocal X-ray fluorescence micro-spectroscopy experiment in tilted geometry  

NASA Astrophysics Data System (ADS)

This paper provides a generalized mathematical model to describe the intensity of primary X-ray fluorescence radiation collected in the tilted confocal geometry mode, where the collimating optics is rotated over an angle relative to a horizontal plane. The influence of newly introduced terms, which take into account the tilted geometry mode, is discussed. The model is verified with a multi-layer test sample scanned in depth. It is proved that for low-Z matrices, the rotation of the detection channel does not induce any significant differences in a reconstruction of the thickness and chemical composition of layers, so that it may safely be ignored.

Czyzycki, Mateusz; Wrobel, Pawel; Lankosz, Marek

2014-07-01

14

X-ray fluorescence and X-ray transmission microtomography imaging system  

Microsoft Academic Search

An X-ray Transmission Microtomography (CT) system combined with an X-ray Fluorescence Microtomography (XRFCT) system was implemented in the Brazilian Synchrotron Light Source (LNLS), Campinas, Brazil. The main aim of this work is to determine the elemental and absorption distribution map in breast tissue samples. The experiments were performed at the X-Ray Fluorescence beamline (D09B-XRF) of the Brazilian Synchrotron Light Source

Gabriela R. Pereira; Henrique S. Rocha; Marcelino J. Anjos; Paulo Faria; Carlos A. Pérez; Ricardo T. Lopes

2007-01-01

15

Wavelength dispersive X-ray fluorescence imaging.  

PubMed

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

Tsuji, Kouichi; Ohmori, Takashi; Yamaguchi, Makoto

2011-08-15

16

Measurements of K x-ray fluorescence parameters  

NASA Astrophysics Data System (ADS)

A simple x-ray fluorescence experiment suitable for graduate and undergraduate laboratories is described. The experiment uses a NaI(Tl) x-ray spectrometer, a weak 57Co radioactive source (~105 Bq), and medium-Z targets of silver, cadmium, indium, and tin. The K x-ray fluorescence yield, ?k, and K x-ray production cross section, ?k, are measured for these targets. Accurate results are achieved by adopting a 2? detection geometry and by optimizing target dimensions for this experimental configuration. The experiment can be completed in 4 h and is suitable for student laboratories.

Bennal, A. S.; Shidling, P. D.; Badiger, N. M.; Thontadarya, S. R.; Hanumaiah, B.

2005-09-01

17

Spatially resolved micro-X-ray fluorescence and micro-X-ray absorption fine structure study of a fractured granite bore core following a radiotracer experiment  

NASA Astrophysics Data System (ADS)

Spatially resolved X-ray absorption and fluorescence investigation with a micrometer-scale resolution on actinide-containing samples provide information necessary for safety assessment of nuclear waste disposal. In this paper one example of such an experiment is presented. This example entails neptunium speciation in a fractured granite bore core from the Swedish Äspö Hard Rock Laboratory following a radiotracer experiment using µ-XAFS and µ-XRF. In order to probe micro-volumes below the surface in the granite samples and thereby avoid potential changes in the Np speciation during cutting of the bore core, a confocal irradiation-detection geometry is employed. µ-XAFS results for a selected granite bore core cross section with ~ 3 nmol Np/g reveal that Np, originally introduced as Np(V) in the tracer cocktail, is present in the granite in its reduced Np(IV) form. The Np(IV) is often present as particles, tens of µm in size. Elemental distribution maps show the tracer Np to be located in fissures and permeable channels not larger than 100 µm. The Np distribution appears often correlated with Zn also present in some fissures. We observe small granite fissures containing Fe (presumably Fe(II)), where we do not detect any Np. It is feasible that inflowing Np(V) has a shorter residence time in large fractures, while in the smaller fissures migration is slower, leading to longer residence times, i.e., reaction times, where it is reduced to less soluble Np(IV) and becomes thereby immobilized.

Denecke, Melissa A.; Brendebach, Boris; De Nolf, Wout; Falkenberg, Gerald; Janssens, Koen; Simon, Rolf

2009-08-01

18

X-ray microprobe for micro x-ray fluorescence and absorption spectroscopies at GSECARS  

Microsoft Academic Search

The hard x-ray microprobe for x-ray fluorescence and absorption spectroscopy at GeoSoilEnviroCARS is presented. Using focused synchrotron radiation from an undulator beamline at the Advanced Photon Source at Argonne National Lab, the x-ray microprobe provides bright, monochromatic x-rays with typical spot sizes down to 1x1 mum for x-ray fluorescence and absorption spectroscopies. Quantitative x-ray fluorescence (XRF) analysis gives precise elemental

M. Newville; S. Sutton; M. Rivers

2002-01-01

19

X-Ray Fluorescent Recovers Ancient Text  

NSDL National Science Digital Library

This article from Cornell University News Service presents an interdisciplinary effort among physicists and classicists to read a weathered 2000-year-old inscription on stone with x-ray fluorescence. The article describes how a powerful x-ray light source at Cornell produced fluorescence in trace elements in the inscribed stone and includes images showing the original inscription. The article is written for the general public.

2008-10-27

20

Coded aperture imaging for fluorescent x-rays  

NASA Astrophysics Data System (ADS)

We employ a coded aperture pattern in front of a pixilated charge couple device detector to image fluorescent x-rays (6-25 KeV) from samples irradiated with synchrotron radiation. Coded apertures encode the angular direction of x-rays, and given a known source plane, allow for a large numerical aperture x-ray imaging system. The algorithm to develop and fabricate the free standing No-Two-Holes-Touching aperture pattern was developed. The algorithms to reconstruct the x-ray image from the recorded encoded pattern were developed by means of a ray tracing technique and confirmed by experiments on standard samples.

Haboub, A.; MacDowell, A. A.; Marchesini, S.; Parkinson, D. Y.

2014-06-01

21

Early experiences with the Mount Allison University four-detector X-ray fluorescence bone lead measurement system  

NASA Astrophysics Data System (ADS)

A four-detector (4 × 500 mm 2) low energy Germanium detector array has recently been acquired for use in a 109Cd source K-shell X-ray fluorescence bone lead measurement system. In this paper, system calibration results are presented, along with preliminary measurement results using lead-doped bone phantoms. Measurement uncertainty and reproducibility values are noted. System comparisons are made with our conventional (1 × 2000 mm 2) detector system, and future directions outlined.

Ahmed, Naseer; Fleming, David E. B.

2007-10-01

22

Synchrotron x-ray fluorescence and extended x-ray absorption fine structure analysis  

SciTech Connect

The advent of dedicated synchrotron radiation sources has led to a significant increase in activity in many areas of science dealing with the interaction of x-rays with matter. Synchrotron radiation provides intense, linearly polarized, naturally collimated, continuously tunable photon beams, which are used to determine not only the elemental composition of a complex, polyatomic, dilute material but also the chemical form of the elements with improved accuracy. Examples of the application of synchrotron radiation include experiments in synchrotron x-ray fluorescence (SXRF) analysis and extended x-ray absorption fine structure (EXAFS) analysis. New synchrotron radiation x-ray microprobes for elemental analysis in the parts per billion range are under construction at several laboratories. 76 references, 24 figures.

Chen, J.R.; Gordon, B.M.; Hanson, A.L.; Jones, K.W.; Kraner, H.W.; Chao, E.C.T.; Minkin, J.A.

1984-01-01

23

Method for X-ray fluorescence spectroscopy  

Microsoft Academic Search

A method and apparatus are described for performing X-ray fluorescence analysis where the physical relationship between the source\\/detector and the object being examined is not controlled. This technique and apparatus is particularly advantageous in performing an in situ analysis of the concentration of one or more elements present in a matrix of a material such as rock. In accordance with

W. C. Boyce; T. E. Hall; L. C. Howard; W. M. Lechelt; W. D. Wittekind

1985-01-01

24

Development of confocal micro X-ray fluorescence instrument using two X-ray beams  

NASA Astrophysics Data System (ADS)

A new confocal micro X-ray fluorescence instrument was developed. This instrument has two independent micro X-ray tubes with Mo targets. A full polycapillary X-ray lens was attached to each X-ray tube. Another half polycapillary lens was attached to a silicon drift X-ray detector (SDD). The focal spots of the three lenses were adjusted to a common position. The effects of the excitation of two X-ray beams were investigated. The instrument enabled highly sensitive three-dimensional X-ray fluorescence analysis. We confirmed that the X-ray fluorescence intensity from the sample increased by applying the two independent X-ray tubes in confocal configuration. Elemental depth profiling of black wheat was demonstrated with the result that each element in the surface coat of a wheat grain showed unique distribution.

Tsuji, Kouichi; Nakano, Kazuhiko; Ding, Xunliang

2007-07-01

25

Development of confocal micro X-ray fluorescence instrument using two X-ray beams  

Microsoft Academic Search

A new confocal micro X-ray fluorescence instrument was developed. This instrument has two independent micro X-ray tubes with Mo targets. A full polycapillary X-ray lens was attached to each X-ray tube. Another half polycapillary lens was attached to a silicon drift X-ray detector (SDD). The focal spots of the three lenses were adjusted to a common position. The effects of

Kouichi Tsuji; Kazuhiko Nakano; Xunliang Ding

2007-01-01

26

A miniature x-ray fluorescence setup  

NASA Astrophysics Data System (ADS)

A miniature low-power x-ray fluorescence (XRF) setup has been designed, realized, and tested in vacuum. The experimental setup is centimeter sized and consists of an x-ray source and an electrically cooled silicon detector. The x-ray source has diamond membrane electrodes; the cathode is a field emitting microstructure and the anode is a metal film deposited on a diamond membrane. Anode radiation emergent through one of the diamond membrane electrodes induces characteristic x-ray radiation from a sample. By miniaturization of an XRF setup extremely low power consumption with acceptable yield and signal level is possible because of the small distances involved between source and sample and between sample and detector. The lightweighted XRF setup is intended for in situ materials analysis, e.g., for spacecraft applications, or probe mounted for portable mineralogy, archaeometry, or forensic equipment. In this article an initial test of the fluorescence setup is described and qualitative experimental results are presented and analyzed.

Ribbing, Carolina; Andersson, Marit; Hjort, Klas; Lundqvist, Hans

2003-07-01

27

X-ray fluorescence imaging with polycapillary X-ray optics  

NASA Astrophysics Data System (ADS)

X-ray fluorescence spectrometry imaging is a powerful tool to provide information about the chemical composition and elemental distribution of a specimen. X-ray fluorescence spectrometry images were conventionally obtained by using a ?-X-ray fluorescence spectrometry spectrometer, which requires scanning a sample. Faster X-ray fluorescence spectrometry imaging would be achieved by eliminating the process of sample scanning. Thus, we developed an X-ray fluorescence spectrometry imaging instrument without sample scanning by using polycapillary X-ray optics, which had energy filter characteristics caused by the energy dependence of the total reflection phenomenon. In the present paper, we show that two independent straight polycapillary X-ray optics could be used as an energy filter of X-rays for X-ray fluorescence. Only low energy X-rays were detected when the angle between the two optical axes was increased slightly. Energy-selective X-ray fluorescence spectrometry images with projection mode were taken by using an X-ray CCD camera equipped with two polycapillary optics. It was shown that Fe K? (6.40 keV) and Cu K? (8.04 keV) could be discriminated for Fe and Cu foils.

Yonehara, Tasuku; Yamaguchi, Makoto; Tsuji, Kouichi

2010-06-01

28

Preliminary results from the viking x-ray fluorescence experiment: The first sample from chryse planitia, Mars  

USGS Publications Warehouse

Iron, calcium, aluminum, silicon, and sulfur are major elements in the first surface sample of Mars that has been analyzed by the Viking x-ray fluorescence spectrometer. Titanium is present in minor quantities. This is consistent with the sample being a mixture of fine silicate and oxide mineral grains, with a significant proportion of sulfates, possibly hydrated. Ferric oxide is regarded as the red pigmenting agent on the martian surface, but if it coats silicate grains, the coatings must be very thin (??? 2 micrometers) or discontinuous. A high abundance of Fe, relatively low abundances of Al, Rb, Sr, and Zr, and a high Ca/K ratio are distinctive features of the spectra. Preliminary determinations indicate the following abundances (as percentages by weight): Fe, 14 ?? 2; Ti < 1; S, 2 to 5; the Ca/K ratio by weight is greater than 5.

Toulmin, III, P.; Clark, B. C.; Baird, A. K.; Keil, K.; Rose, Jr. , H. J.

1976-01-01

29

X-ray fluorescence microscopy of olfactory receptor neurons  

NASA Astrophysics Data System (ADS)

We report a x-ray fluorescence microscopy study of cells and tissues from the olfactory system of Xenopus laevis. In this experiment we focus on sample preparation and experimental issues, and present first results of fluorescence maps of the elemental distribution of Cl, K, Ca, P, S and Na both in individual isolated neural cells and in cross-sections of the same tissue.

Du?i?, T.; Breunig, E.; Schild, D.; Herbst, J.; Novįkovį, E.; Susini, J.; Tucoulu, R.; Salditt, T.

2009-09-01

30

Simulation of x-ray absorption near-edge spectra and x-ray fluorescence spectra of optically excited molecules  

SciTech Connect

The x-ray absorption near-edge spectra (XANES) and fluorescence spectra of molecules in the ground state and optically excited states are computed using time-dependent density functional theory and time-dependent Hartree-Fock theory. The calculated XANES spectra of optically excited methanol, benzonitrile, hydrogen sulphide, and titanium tetrachloride and the fluorescence spectra of optically excited methanol can be used to simulate ultrafast optical pump/x-ray probe experiments.

Pandey, R.K.; Mukamel, Shaul [Department of Chemistry, University of California, Irvine, California 92697-2025 (United States)

2006-03-07

31

Extended X-Ray Absorption Fine Structure (EXAFS) in X-ray Fluorescence Spectra  

Microsoft Academic Search

Aluminum K-LL radiative Auger X-ray fluorescence spectra of AlPO4 and Al2O3 powders are measured using an X-ray fluorescence spectrometer for elemental analysis. We demonstrate that the Fourier transform of the oscillation in the radiative Auger spectra has information similar to that of the extended X-ray absorption fine structure (EXAFS). The Al O distances in AlPO4 and Al2O3 are determined by

Jun Kawai; Kouichi Hayashi; Yasuhiro Awakura

1997-01-01

32

First X-ray fluorescence excited Kossel diffraction in SEM  

Microsoft Academic Search

.  We present, for the first time, X-ray fluorescence excited Kossel patterns in the scanning electron microscope by way of a\\u000a compact X-ray tube and a focusing polycapillary lens. Both the diffraction geometry in transmission and in back reflection\\u000a can be carried out. The way is paved for the advantageous combination of micro-X-ray fluorescence analysis, the Laue method,\\u000a and the X-ray

Enrico Langer; Michael Haschke; Siegfried Däbritz

2008-01-01

33

X-ray Fluorescence (XRF) Assay Using Laser Compton Scattered (LCS) X-rays  

SciTech Connect

Laser Compton Scattered (LCS) X-rays are produced as a result of the interaction between accelerated electrons and a laser beam. The yield of LCS X-rays is dependent on the laser power, angle of collision between interacting particles, and the electron linear accelerator's (linac) electron beam energy and its current. One of our research goals at the Idaho Accelerator Center (IAC) focuses on applications such as detection and imaging of fissionable isotopes for nuclear non-proliferation, safeguards and homeland security. Quasi monochromatic LCS X-rays offer much better signal-to-noise ratios for such applications. The energy of LCS X-rays is tunable, that enable element-specific analysis. Two sharp 36.5 keV and 98.4 keV LCS peaks were observed in two separate experiments based on electron beams tuned at 32 MeV and 37 MeV, that were brought in collision with the (Power){sub peak} = 4 GW Nd.YAG laser operating at 532 nm and 266 nm wavelengths. The linac was operating at 60 Hz with an electron beam pulse length of about 50 ps and a peak current of about 7 A. We exploited X-ray fluorescence (XRF) techniques to identify elemental K{alpha}{sub 1}, K{alpha}{sub 2}, and K{beta}{sub 1} lines in a high-purity germanium (HPGe) detector, with a 0.5 mm thick Beryllium (Be) absorbing layer, emitted from tin (Sn), cadmium (Cd), silver (Ag), gold (Au), and lead (Pb) foils with thicknesses ranging from 25-500 {mu}m, following absorption of 36.1 keV and 98.4 keV LCS X-rays. These reference foils were used for the proof of principle, and some have atomic numbers near to that of relevant fission products.

Naeem, Syed F.; Chouffani, Khalid; Wells, Douglas P. [Idaho State University, Idaho Accelerator Center, Campus Box 8263, Pocatello ID 83209 (United States)

2009-03-10

34

X-ray Fluorescence (XRF) Assay Using Laser Compton Scattered (LCS) X-rays  

NASA Astrophysics Data System (ADS)

Laser Compton Scattered (LCS) X-rays are produced as a result of the interaction between accelerated electrons and a laser beam. The yield of LCS X-rays is dependent on the laser power, angle of collision between interacting particles, and the electron linear accelerator's (linac) electron beam energy and its current. One of our research goals at the Idaho Accelerator Center (IAC) focuses on applications such as detection and imaging of fissionable isotopes for nuclear non-proliferation, safeguards and homeland security. Quasi monochromatic LCS X-rays offer much better signal-to-noise ratios for such applications. The energy of LCS X-rays is tunable, that enable element-specific analysis. Two sharp 36.5 keV and 98.4 keV LCS peaks were observed in two separate experiments based on electron beams tuned at 32 MeV and 37 MeV, that were brought in collision with the (Power)peak = 4 GW Nd.YAG laser operating at 532 nm and 266 nm wavelengths. The linac was operating at 60 Hz with an electron beam pulse length of about 50 ps and a peak current of about 7 A. We exploited X-ray fluorescence (XRF) techniques to identify elemental K?1, K?2, and K?1 lines in a high-purity germanium (HPGe) detector, with a 0.5 mm thick Beryllium (Be) absorbing layer, emitted from tin (Sn), cadmium (Cd), silver (Ag), gold (Au), and lead (Pb) foils with thicknesses ranging from 25-500 ?m, following absorption of 36.1 keV and 98.4 keV LCS X-rays. These reference foils were used for the proof of principle, and some have atomic numbers near to that of relevant fission products.

Naeem, Syed F.; Chouffani, Khalid; Wells, Douglas P.

2009-03-01

35

Fundamental characteristics of hybrid X-ray focusing optics for micro X-ray fluorescence analysis  

NASA Astrophysics Data System (ADS)

We developed a hybrid X-ray focusing optics, which consisted of a polycapillary X-ray lens (PCXL) and a tungsten conical pinhole (WCP) for micro X-ray fluorescence (?-XRF) analysis. A single PCXL produced an X-ray micro beam with a spot size of 12 ?m. We developed a WCP by using a laser-ablation technique with an input diameter of 39 ?m, an output diameter of 2.5 ?m, and a thickness of 0.5 mm in a conical shape. This hybrid X-ray optics gave a small spot size of 2.8 ?m with a small divergent angle of 12 mrad.

Komatani, Shintaro; Nakamachi, Kazuo; Nakano, Kazuhiko; Ohzawa, Sumito; Uchihara, Hiroshi; Bando, Atsushi; Tsuji, Kouichi

2013-08-01

36

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

37

The Diffuse X-ray Spectrometer Experiment  

NASA Astrophysics Data System (ADS)

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

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

1992-10-01

38

X-ray reference-intensity and X-ray fluorescence analyses of Salton Sea core  

Microsoft Academic Search

Quantitative X-ray powder diffraction (XRD) and X-ray transmission (XRT) procedures have been combined with X-ray fluorescence (XRF) and other spectroscopic methods to characterize the mineralogy and chemistry of 33 core samples obtained from the Salton Sea Scientific Drilling Program (SSSDP) well. Major mineral components in the SSSDP samples include quartz, orthoclase, sodic plagioclase, chlorite, epidote, illite, and calcite, with minor

B. L. Davis; C. K. Jr. Shearer; S. B. Simon; M. N. Spilde; J. J. Papike; J. C. Laul

2009-01-01

39

Fluorescence x-ray absorption fine structure measurements using a synchrotron radiation x-ray microprobe  

Microsoft Academic Search

X-ray absorption fine structure (XAFS) measurements in regions less than 20 ?m in diameter were realized using an x-ray microprobe employing the fluorescence detection method. To realize an energy tunable intense small x-ray beam, an ellipsoidal mirror was used as the synchrotron radiation focusing element combined with a double-crystal monochromator. Distortion of a XAFS spectrum due to the self-absorption effect

Shinjiro Hayakawa; Yohichi Gohshi; Atsuo Iida; Sadao Aoki; Kohei Sato

1991-01-01

40

Characterization of small particles by micro X-ray fluorescence  

Microsoft Academic Search

Micro X-ray fluorescence was used to study both homogeneous and heterogeneous particle systems. Specifically, homogeneous glass microspheres and heterogeneous soil particle samples were prepared by both bulk and single particle sample preparation methods for evaluation by micro X-ray fluorescence. Single particle sample preparation methods allow for single particles from a collected sample to be isolated and individually presented to the

Thomasin C. Miller; Helen Langley Dewitt; George J. Havrilla

2005-01-01

41

Use of Computers for X-Ray Absorption Edge, X-Ray Fluorescence, Electron Probe, and X-Ray Diffraction Analyses at Oak Ridge National Laboratory  

Microsoft Academic Search

Computers have been used by the X-Ray Analysis Section at Oak Ridge National Laboratory (ORNL) for several years. Codes are used for processing x-ray absorption edge, x-ray fluorescence, and electron probe data. A subroutine is available for plotting the x-ray fluorescence and electron probe data. The computer is also used to calculate lattice parameters from powder x-ray diffraction data.

H. W. Dunn

1972-01-01

42

Development and applications of grazing exit micro X-ray fluorescence instrument using a polycapillary X-ray lens  

Microsoft Academic Search

A polycapillary X-ray lens is an effective optics to obtain a ?m-size X-ray beam for micro-X-ray fluorescence spectrometry (?-XRF). We developed a ?-XRF instrument using a polycapillary X-ray lens, which also enabled us to perform Grazing Exit ?-XRF (GE-?-XRF). The evaluated diameter of the primary X-ray beam was 48 ?m at the focal distance of the X-ray lens. Use of

T. Emoto; Y. Sato; Y. Konishi; X. Ding; K. Tsuji

2004-01-01

43

X-ray fluorescence analysis based on Kumakhov optics  

Microsoft Academic Search

The use of Kumakhov optics in x-ray fluorescence analysis is considered. Thanks to high efficiency of a polycapillary lens the concentration of x-ray detector in a close proximity to the sample decreases sufficiently the time of exposure. It is shown experimentally that in the case of use of a small x-ray source with power of 2W the minimal detection limit

Svetlana V. Nikitina; Nariman S. Ibraimov; Alexander S. Stcherbakov

1998-01-01

44

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

45

Industrial x-ray fluorescence analysis new applications and challenges for cryogenic detectors  

Microsoft Academic Search

Cryogenic, high-resolution X-ray detectors have potential applications in industrial X-ray fluorescence (XRF) analysis. We discuss various XRF analysis techniques currently used in the semiconductor industry, problems encountered due to limitations of current detectors and the potential benefits of using cryogenic detectors in these applications. We give examples of demonstration experiments, compare the performance of current conventional and cryogenic X-ray spectrometers

1997-01-01

46

X-ray fluorescence analysis of spent reactor fuel solutions  

Microsoft Academic Search

The present work examines the possibility of laboratory analytic control by means of a crystal-free x-ray fluorescence analysis (XRFA) installation specifically designed for this purpose with a prior selection of fluorescent emissions by energy. Monitoring by fluorescent emissions from selenium positioned in the installation along with a metering cuvette allows the exclusion of errors associated with the instability of the

V. V. Berdikov; B. S. Iokhin

1987-01-01

47

Are Atom-sized X-ray Experiments Possible?  

SciTech Connect

The success of advanced microbeam facilities at third generation synchrotron sources have inspired us to ask ultimate questions such as how small an x-ray beam diameter can be made. With the hope of more brilliant Energy Recovery Linac or X-ray Free Electron Laser sources due to arrive in the next decade, it appears possible to think of fluorescent x-ray experiments that can be performed on even a single impurity atom in a silicon wafer, for instance. Not all x-ray optical developers are yet convinced, however, so there is critical need to assess whether in principle this can really be done or not. We are optimistic that 1 nm diameter x-ray beams can be made of sufficient flux from future sources or even demonstration experiments at lower count rates from 3rd generation sources if it turns out to be worthwhile to actively develop optics and methods that vastly exceed the current x-ray microbeam capabilities.

Bilderback, Donald H. [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States); School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853 (United States); Huang Rong [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States)

2004-05-12

48

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

Microsoft Academic Search

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

Ariadna Mendoza Cuevas; Homero Perez Gravie

2011-01-01

49

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

Microsoft Academic Search

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

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

50

Capillary optics for micro x-ray fluorescence analysis  

NASA Astrophysics Data System (ADS)

Practically achieved parameters of capillary optics are presented. A micro x-ray fluorescence (XRF) arrangement was realized by using a microfocus x-ray tube and a capillary optic. Several examples for application of micro XRF are given. It was shown that polycapillary lenses free of the ``halo effect'' well suited for micro XRF of heavy elements can be manufactured. Limits of opportunities for micro XRF applications and further development for micro XRF by using capillary optics are analyzed.

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

2005-06-01

51

Capillary optics for micro x-ray fluorescence analysis  

SciTech Connect

Practically achieved parameters of capillary optics are presented. A micro x-ray fluorescence (XRF) arrangement was realized by using a microfocus x-ray tube and a capillary optic. Several examples for application of micro XRF are given. It was shown that polycapillary lenses free of the 'halo effect' well suited for micro XRF of heavy elements can be manufactured. Limits of opportunities for micro XRF applications and further development for micro XRF by using capillary optics are analyzed.

Bjeoumikhov, A.; Langhoff, N.; Bjeoumikhova, S.; Wedell, R. [IfG Institut fuer Geraetebau GmbH, Rudower Chaussee 29/31, 12489 Berlin (Germany); Bundesanstalt fuer Materialforschung und-pruefung, 12200 Berlin (Germany); IAP Institut fuer angewandte Photonik e. V., Rudower Chaussee 29/31, 12489 Berlin (Germany)

2005-06-15

52

Sampling the Soils around a Residence Containing Lead-Based Paints: An X-Ray Fluorescence Experiment  

ERIC Educational Resources Information Center

Sampling experiments utilizing field portable instruments are instructional since students collect data following regulatory protocols, evaluate it, and begin to recognize their civic responsibilities upon collecting useful data. A lead-in-soil experiment educated students on a prevalent exposure pathway. The experimental site was a pre-1950…

Bachofer, Steven J.

2008-01-01

53

X-ray fluorescence-spectometer\\/diffractometer for future lunar lander\\/rover mission  

Microsoft Academic Search

A miniaturized scientific instrument is being developed for a Japanese future lunar lander and rover mission to perform both of X-ray fluorescence (XRF) spectroscopy and X ray diffractometry (XRD). Onboard micro X ray tube with a fine focused-- collimator generates primary X-rays that excites fluorescence X rays characteristic- to component elements of the targeted sample and, at the same time,

K. Shirai; M. Aoki; S. Ito; T. Okada; Y. Yamamoto; T. Arai; K. Akagawa; M. Kato

2002-01-01

54

Development and application of glancing incident X-ray fluorescence spectrometry using parallel polycapillary X-ray lens  

Microsoft Academic Search

A new glancing incident X-ray fluorescence (GIXRF) spectrometer using parallel polycapillary X-ray lens has been developed. Integrated with a Zr filter and slits, a highly collimated and monochromatic X-ray beam has been achieved. This method eliminated the monochromator used in the conventional GIXRF method. Moreover the parallel X-ray lens increased the acceptance solid angle and hence increases intensities of the

Jun Yang; Dandan Zhao; Qing Xu; Xunliang Ding

2009-01-01

55

Wavelength-dispersive x-ray fluorescence detector  

Microsoft Academic Search

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

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

1995-01-01

56

X-ray fluorescence analysis of various alloys. Part 1  

SciTech Connect

For a number of years, x-ray fluorescence spectrometry has been used in the Y-12 Plant Laboratory for the analysis of a wide variety of materials. During the past few years, the technique has been applied to the analysis of a large number of experimental alloys. The general procedure consists of the following steps: (1) ignition of the alloy to oxides, (2) addition of suitable internal standards, (3) dissolution of the oxides and internal standards by sodium tetraborate (borax) fusion, (4) casting a pellet from the fusion in a graphite mold (Figure 1), and (5) determination of the major constituents by x-ray fluorescence spectrometry.

Charles, J.W. Jr.; Ferguson, M.R.; Eager, M.H.

1980-02-15

57

Unsupervised cell identification on multidimensional X-ray fluorescence datasets.  

PubMed

A novel approach to locate, identify and refine positions and whole areas of cell structures based on elemental contents measured by X-ray fluorescence microscopy is introduced. It is shown that, by initializing with only a handful of prototypical cell regions, this approach can obtain consistent identification of whole cells, even when cells are overlapping, without training by explicit annotation. It is robust both to different measurements on the same sample and to different initializations. This effort provides a versatile framework to identify targeted cellular structures from datasets too complex for manual analysis, like most X-ray fluorescence microscopy data. Possible future extensions are also discussed. PMID:24763647

Wang, Siwei; Ward, Jesse; Leyffer, Sven; Wild, Stefan M; Jacobsen, Chris; Vogt, Stefan

2014-05-01

58

X-ray fluorescence analysis major elements in silicate minerals  

SciTech Connect

An automated wavelength-dispersive x-ray fluorescence spectrometer is operational for analysis of major elements in rocks and minerals. Procedures for trace-element analysis are being developed. Sample preparation methods and analytical techniques are similar to those commonly used elsewhere, but data reduction is conducted by the Fundamental Parameters program developed by Criss. Unlike empirically derived calibration curves, this data reduction method considers x-ray absorption and secondary fluorescence, which vary with differences in sample composition. X-ray intensities for each element from several standards are averaged to develop a theoretical standard for comparison with samples of unknown composition. Accurate data for samples with wide compositional ranges result from these data reduction and standardization techniques.

Hagan, R.C.

1982-09-01

59

X-ray fluorescence analysis of various alloys. Part 1  

Microsoft Academic Search

For a number of years, x-ray fluorescence spectrometry has been used in the Y-12 Plant Laboratory for the analysis of a wide variety of materials. During the past few years, the technique has been applied to the analysis of a large number of experimental alloys. The general procedure consists of the following steps: (1) ignition of the alloy to oxides,

J. W. Jr. Charles; M. R. Ferguson; M. H. Eager

1980-01-01

60

Trace Metal Water Pollutants Determined by X-Ray Fluorescence.  

National Technical Information Service (NTIS)

X-ray fluorescence analysis was evaluated for determining trace metals in samples of interest in the Water Quality Control Program. A number of toxic elements including Pb were determined in Potomac River water and Blue Plains sewage sludge. Analysis by x...

P. G. Burkhalter

1973-01-01

61

X-ray fluorescence camera for biomedical imaging  

NASA Astrophysics Data System (ADS)

X-Ray Fluorescence (XRF) analysis is useful for measuring density distributions of contrast media in vivo. An XRF camera was developed to carry out mapping for iodine-based contrast media used in medical angiography. In this camera, objects are exposed by an x-ray beam formed using a 3.0-mm-diameter lead hole. Next, cerium K-series characteristic x-rays are absorbed effectively by iodine media in objects, and iodine fluorescences are produced from the objects. Iodine K? fluorescences are selected out using a 58-?m-thick stannum filter and are detected by a cadmium telluride (CdTe) detector. K? rays are discriminated out by a multichannel analyzer (MCA), and photon number is counted by a counter board (CB). The objects are moved and scanned using an x-y stage driven by a two-stage controller, and x-ray images obtained by iodine mapping are shown in a personal computer (PC) monitor. In particular, iodine fluorescences were produced from remanent iodine elements in a cancer region of a rabbit ear.

Matsukiyo, Hiroshi; Sato, Eiichi; Abderyim, Purkhet; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Nagao, Jiro; Nomiya, Seiichiro; Sato, Koetsu; Ogawa, Akira; Sato, Shigehiro; Ichimaru, Toshio

2008-08-01

62

Bone Lead Measured by X-ray Fluorescence: Epidemiologic Methods  

Microsoft Academic Search

In vivo X-ray fluorescence (XRF) measurement of bone lead concentration (XRF) has emerged as an important technique for future epidemiological studies of long-term toxicity. Several issues germane to epidemiologic methodology need to be addressed, however. First, sources of variability in measurements of bone lead need to be quantified, including imprecision related to the physical measurement itself and the variability of

Howard Hu; Antonio Aro; Andrea Rotnitzky

1995-01-01

63

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

64

Basic studies on x-ray fluorescence analysis for active x-ray spectrometer on SELENE-2  

NASA Astrophysics Data System (ADS)

An active X-ray spectrometer (AXS) is now being developed as a payload candidate for the rover on SELENE-2, the next Japanese lunar exploration mission. The AXS will determine the chemical compositions of lunar rocks and regolith around the landing site. The surface of lunar rock samples will be ground using a rock abrasion tool. Thus, fundamental studies on the X-ray fluorescence analysis for lunar rocks and regolith are required to design and develop the AXS. In this study, we have investigated the X-ray fluorescence analysis in order to evaluate the effects of surface roughness of samples and the angle of incident and emergent X-rays. It was found that the fluorescent X-ray yield for low energy X-rays, i.e. the light elements, decreases at rough surface samples. This effect of surface roughness becomes small for smooth surface samples. It was also found that the fluorescent X-ray yield depends on the incident angle, which is attributed to the fact that the X-ray fluorescence occurs closer to the sample surface at larger incident angles. Since the emergent X-rays are affected by the detection geometry and surface roughness, the incident angle effect also depends on the above conditions.

Kusano, Hiroki; Hasebe, Nobuyuki; Nagaoka, Hiroshi; Kodama, Takuro; Oyama, Yuki; Tanaka, Reiko; Amano, Yoshiharu; Kim, Kyeong J.; Matias Lopes, Josč A.

2013-09-01

65

Sulfur abundance of asteroid 25143 Itokawa observed by X-ray fluorescence spectrometer onboard Hayabusa  

Microsoft Academic Search

The Japanese Hayabusa spacecraft successfully carried out in situ observations of S-class asteroid 25143 Itokawa, including the surface major elemental analysis with the X-ray fluorescence spectrometer (XRS-Hayabusa). Our previous results for the X-ray experiments (Okada et al., 2006a) indicated that major elemental ratios of Mg\\/Si and Al\\/Si on the surface of Itokawa resemble ordinary LL- or L-chondrites more than any

T. Arai; T. Okada; Y. Yamamoto; K. Ogawa; K. Shirai; M. Kato

2008-01-01

66

X-ray Fluorescent Phosphors as in Situ Markers of X-ray Position for High-Pressure X-ray Techniques: Equation of State and X-ray Fluorescence Spectra to 40 GPa  

Microsoft Academic Search

Their small size and heterogeneity make high-pressure samples in the diamond-anvil cell difficult to place perfectly in an x-ray beam to perform any of several analytical techniques (diffraction, scattering, etc.). X-ray fluorescent materials may help to solve this problem by providing a visual marker of the precise location of the x-ray beam or probe. In order to assess the utility

L. R. Benedetti; W. A. Crichton; M. Mezouar

2004-01-01

67

Focusing crystal von Hamos spectrometer for x-ray spectroscopy and x-ray fluorescence applications  

NASA Astrophysics Data System (ADS)

The use of bent crystals with high integrated reflectivity in focusing crystal spectrometers (Johann and von Hamos schemes) is considered. It is shown that in a von Hamos scheme mosaic focusing takes place. Thus a mosaic crystal simultaneously provides high spectral resolution and high efficiency. Expressions for the mosaic focusing are obtained. Focusing mica and graphite crystal von Hamos spectrometers (radius of crystal curvature is 20 mm) are investigated: spectral and spatial resolution and absolute efficiency are measured in a spectral range of 2 - 2.6 angstroms using laser-produced plasma and iron isotope x-ray sources. The mica crystal spectrometer showed high spatial (up to 10 micrometers ) and spectral ((lambda) /(delta) (lambda) approximately 1000) resolution, whereas the graphite spectrometer showed very high efficiency (30 - 70 times higher than the mica crystal) and moderate spectral resolution ((lambda) /(delta) (lambda) approximately 500 - 750). In the latter case mosaic focusing is observed: spectral resolution is 10 - 15 times higher than spectral resolution determined by the mosaic spread of the crystal ((lambda) /(delta) (lambda) approximately 50). The results allow one to estimate a maximum efficiency for focusing crystal spectrometers. Prospects for using the von Hamos spectrometers for x-ray spectroscopy and x-ray fluorescence are considered.

Shevelko, Alexander P.; Antonov, Alexander A.; Grigorieva, Inna G.; Kasyanov, Yury S.; Knight, Larry V.; Reyes-Mena, Arturo; Turner, Clark; Wang, Quan; Yakushev, Oleg F.

2000-11-01

68

An investigation of X-ray fluorescence analysis with an X-ray focusing system (X-ray lens)  

Microsoft Academic Search

Divergent X-ray radiation has been focused into a small spot (diameter 500 mum) by an X-ray lens made of polycapillaries, increasing the power density by 104 times. The new X-ray lens has been applied to the XRF technique. Limits of detection of 10-9-10-10g have been obtained by means of the new technique with an X-ray tube of 2 W power.

Yan Yiming; Ding Xunliang

1993-01-01

69

Soft X-ray generation experiment at the Tsinghua Thomson scattering X-ray source  

NASA Astrophysics Data System (ADS)

The development, design, and construction of the Tsinghua Thomson scattering X-ray (TTX) source have been ongoing since 2001. The TTX source is based on the Thomson scattering of a femtosecond laser pulse by a relativistic electron beam, which aims at an ultra-fast, high-flux, monochromatic, and tunable X-ray source for scientific, medical, and industrial applications. A recent experiment sought to generate a soft X-ray pulse through Thomson scattering. In this experiment, a 3-eV electron beam generated from a photocathode radio-frequency gun is focused by quadrupole magnets to several hundred microns and collided with a 120-mJ, 60-fs laser beam. The generated X-ray is detected by a micro-channel plate. The energy, pulse duration, and number of X-ray photons is estimated to be 290.4 eV, 1 ps, and 6.4×103, respectively.

Du, Yingchao; Yan, Lixin; Hua, Jianfei; Du, Qiang; Li, Renkai; Shi, Jiaru; Huang, Wenhui; Chen, Huaibi; Tang, Chuanxiang

2011-05-01

70

Performances of capillary X-ray optics for confocal three-dimensional micro-X-ray fluorescence technology  

Microsoft Academic Search

The performances of capillary X-ray optics (CXRO) for confocal three-dimensional micro-X-ray fluorescence (3D Micro-XRF) technology are presented. In particular, the energy dependence of the collecting angle and input focal spot size of the polycapillary parallel X-ray lens (PPXRL), and the energy dependence of spatial resolution of the confocal 3D Micro-XRF spectrometer based on the CXRO are reported. In order to

Tianxi Sun; Zhiguo Liu; Yude Li; Guanghua Zhu; Xiaoyan Lin; Ping Luo; Qiuli Pan; Hui Liu; Yuepeng Teng; Ke Yang; Xunliang Ding

2009-01-01

71

Solving the micro-to-macro spatial scale problem with milliprobe x-ray fluorescence\\/x-ray spectrum imaging  

Microsoft Academic Search

Milliprobe x-ray fluorescence (mXRF) with x-ray spectrum imaging (XSI) enables elemental mapping over centimeter lateral distances with a resolution of 40-150 mum. While highly complementary to classic elemental mapping scanning electron microscopy\\/energy dispersive x-ray spectrometry (SEM\\/EDS), mXRF has several advantages: (1) The lack of electron bremsstrahlung in the XRF spectrum, except for the elastic scattering of the primary continuum, means

Dale E. Newbury; Jeff M. Davis

2009-01-01

72

Non-destructive surface characterization of float glass: X-ray reflectivity and grazing incidence X-ray fluorescence analysis  

Microsoft Academic Search

In the present study we have carried out non-destructive surface characterization of a float glass using total reflection X-ray fluorescence (TXRF) technique and X-ray reflectivity (XRR). The in-depth distribution of Sn and Fe impurities has been determined by TXRF where as X-ray optical properties such as r.m.s surface roughness, refractive index, etc., have been derived by XRR. The results obtained

M. K. Tiwari; M. H. Modi; G. S. Lodha; A. K. Sinha; K. J. S. Sawhney; R. V. Nandedkar

2005-01-01

73

Bent silicon crystal in the Laue geometry to resolve x-ray fluorescence for x-ray absorption spectroscopy.  

SciTech Connect

A highly strained, curved silicon crystal in the Laue geometry has been used as a large-area x-ray fluorescence analyzer for x-ray absorption spectroscopy. The analyzer is able to resolve the L{alpha} fluorescence lines for neighboring actinide elements. A large gain in the signal to background ratio has been demonstrated for small quantities of Np in the presence of U, with the U fluorescence peak approaching 1000 times the magnitude of the off-peak background.

Kropf, A. J.; Finch, R. J.; Fortner, J. A.; Aase, S. B.; Chemical Engineering

2003-11-01

74

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

NASA Astrophysics Data System (ADS)

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

Mendoza Cuevas, Ariadna; Perez Gravie, Homero

2011-03-01

75

Development and application of glancing incident X-ray fluorescence spectrometry using parallel polycapillary X-ray lens  

NASA Astrophysics Data System (ADS)

A new glancing incident X-ray fluorescence (GIXRF) spectrometer using parallel polycapillary X-ray lens has been developed. Integrated with a Zr filter and slits, a highly collimated and monochromatic X-ray beam has been achieved. This method eliminated the monochromator used in the conventional GIXRF method. Moreover the parallel X-ray lens increased the acceptance solid angle and hence increases intensities of the excitation spectrum. In this paper, this method has been applied in analysis of single crystal and film sample.

Yang, Jun; Zhao, Dandan; Xu, Qing; Ding, Xunliang

2009-04-01

76

Laboratory x-ray fluorescence tomography for high-resolution nanoparticle bio-imaging.  

PubMed

We demonstrate that nanoparticle x-ray fluorescence computed tomography in mouse-sized objects can be performed with very high spatial resolution at acceptable dose and exposure times with a compact laboratory system. The method relies on the combination of the 24 keV line-emission from a high-brightness liquid-metal-jet x-ray source, pencil-beam-forming x-ray optics, photon-counting energy-dispersive detection, and carefully matched (Mo) nanoparticles. Phantom experiments and simulations show that the arrangement significantly reduces Compton background and allows 100 ?m detail imaging at dose and exposure times compatible with small-animal experiments. The method provides a possible path to in vivo molecular x-ray imaging at sub-100 ?m resolution in mice. PMID:24784104

Hertz, Hans M; Larsson, Jakob C; Lundström, Ulf; Larsson, Daniel H; Vogt, Carmen

2014-05-01

77

Estimating particle size effects in X-ray fluorescence spectrometry  

Microsoft Academic Search

The influence of size of particles on the X-ray fluorescence intensity for powdered substances with different sized particles is estimated, based on a simple modification of the Berry–Furuta–Rhodes formulae. Analytical expressions are obtained for the model of a powder substance consisting of particles of various sizes distributed randomly in the sample volume. The results of calculations by these expressions agree

A. L. Finkelshtein; N. Brjansky

2009-01-01

78

X-ray fluorescence analysis major elements in silicate minerals  

Microsoft Academic Search

An automated wavelength-dispersive x-ray fluorescence spectrometer is operational for analysis of major elements in rocks and minerals. Procedures for trace-element analysis are being developed. Sample preparation methods and analytical techniques are similar to those commonly used elsewhere, but data reduction is conducted by the Fundamental Parameters program developed by Criss. Unlike empirically derived calibration curves, this data reduction method considers

Hagan

1982-01-01

79

High-throughput screening with micro-x-ray fluorescence  

Microsoft Academic Search

Micro-x-ray fluorescence (MXRF) is a useful characterization tool for high-throughput screening of combinatorial libraries. Due to the increasing threat of use of chemical warfare (CW) agents both in military actions and against civilians by terrorist extremists, there is a strong push to improve existing methods and develop means for the detection of a broad spectrum of CW agents in a

George J. Havrilla; Thomasin C. Miller

2005-01-01

80

Development and applications of grazing exit micro X-ray fluorescence instrument using a polycapillary X-ray lens*1  

NASA Astrophysics Data System (ADS)

A polycapillary X-ray lens is an effective optics to obtain a ?m-size X-ray beam for micro-X-ray fluorescence spectrometry (?-XRF). We developed a ?-XRF instrument using a polycapillary X-ray lens, which also enabled us to perform Grazing Exit ?-XRF (GE-?-XRF). The evaluated diameter of the primary X-ray beam was 48 ?m at the focal distance of the X-ray lens. Use of this instrument enabled two-dimensional mapping of the elemental distributions during growth of the plant "Quinoa". The results of the mapping revealed elemental transition during growth. In addition, a small region of thin film was analyzed by GE-?-XRF. We expect that GE-?-XRF will become an effective method of estimating the film thickness of a small region.

Emoto, T.; Sato, Y.; Konishi, Y.; Ding, X.; Tsuji, K.

2004-08-01

81

Determination of regional myocardial perfusion by x-ray fluorescence  

SciTech Connect

Validation studies were performed to demonstrate the effectiveness of an x-ray induced fluorescence system in quantitating regional myocardial perfusion in vivo. In a series of 13 open-chested canines, x-ray induced fluorescence was used to simultaneously monitor iodine concentration transients which arose in the left ventricular lumen and in the myocardium after the intravenous injection of an iodinated flow tracer. Deconvolution of the recorded transients produced a transfer function from which the mean transit time for the tracer to travel between the left ventricular lumen and the myocardium was calculated. Measurements of regional myocardial perfusion (Q) made by radioactive microspheres were compared with the reciprocals of the mean transit times (MTT-1) and gave a linear correlation (n = 38): MTT-1 = 0.033 + 0.069 Q, r = 0.71. Comparison of the percent change in perfusion (dQ) relative to a control study for each dog with the percent change in the respective reciprocals of the mean transit times (dMTT-1) produced a linear correlation coefficient of r = 0.88 for the regression line dMTT-1 = 0.46 dQ - 10.7. The x-ray induced fluorescence system may provide a minimally invasive means for monitoring iodine concentration transients and determining relative, if not absolute, measures of regional myocardial perfusion.

Palmer, B.M.; McInerney, J.J. (Pennsylvania State Univ., University Park (USA))

1990-05-01

82

X-ray fluorescence\\/diffraction analyzer for the SELENE-B lander\\/rover mission  

Microsoft Academic Search

A miniaturized X-ray fluorescence and diffraction analyzer is being developed for the SELENE-B, a future Japanese lunar lander and rover mission, to analyze major elemental composition and mineralogy. An onboard micro X-ray tube with a fine focus collimator is used to generate primary X-rays that excite fluorescence X-rays characteristic of major elements in collected samples; the primary X-rays are also

K. Shirai; M. Aoki; T. Okada; Y. Yamamoto; T. Arai; K. Akagawa; M. Kato

2003-01-01

83

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

Microsoft Academic Search

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

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

2010-01-01

84

Soft X-ray generation experiment at the Tsinghua Thomson scattering X-ray source  

Microsoft Academic Search

The development, design, and construction of the Tsinghua Thomson scattering X-ray (TTX) source have been ongoing since 2001. The TTX source is based on the Thomson scattering of a femtosecond laser pulse by a relativistic electron beam, which aims at an ultra-fast, high-flux, monochromatic, and tunable X-ray source for scientific, medical, and industrial applications. A recent experiment sought to generate

Yingchao Du; Lixin Yan; Jianfei Hua; Qiang Du; Renkai Li; Jiaru Shi; Wenhui Huang; Huaibi Chen; Chuanxiang Tang

2011-01-01

85

Advanced detection systems for X-ray fluorescence excitation spectroscopy.  

PubMed

This paper accounts for selected detector developments carried out over the past 15 years within the ESRF X-ray Absorption Spectroscopy group. This includes various types of photodiodes used as integrated current detectors. Special emphasis is put on the long-standing development of a Si drift-diode array suitable for energy-dispersive detection of X-ray fluorescence. This detector, which is now operational, was used to record high-quality XMCD/XAFS spectra on [Fe70Pt30] nanoparticles highly dispersed on a Si wafer. Using numerically deconvoluted spectra, energy resolution was decreased to 82 eV for the Si Kalphabeta line, 126 eV for the Fe Kalpha line and 176 eV for the Pt Lalpha line. A high-vacuum-compatible high-energy-resolution crystal analyzer was also installed on ID12, making it possible to record X-ray fluorescence excitation spectra in the photon-in/photon-out mode over a wide spectral range. Prospects of adapting these methods in order to investigate biological samples are briefly discussed. PMID:15616366

Goulon, J; Rogalev, A; Goujon, G; Gauthier, Ch; Moguiline, E; Solé, A; Feite, S; Wilhelm, F; Jaouen, N; Goulon-Ginet, Ch; Dressler, P; Rohr, P; Lampert, M-O; Henck, R

2005-01-01

86

X-ray fluorescence spectrometry of asteroid Itokawa by Hayabusa.  

PubMed

X-ray fluorescence spectrometry of asteroid 25143 Itokawa was performed by the x-ray spectrometer onboard Hayabusa during the first touchdown on 19 November 2005. We selected those data observed during relatively enhanced solar activity and determined average elemental mass ratios of Mg/Si = 0.78 +/- 0.09 and Al/Si = 0.07 +/- 0.03. Our preliminary results suggest that Itokawa has a composition consistent with that of ordinary chondrites, but primitive achondrites cannot be ruled out. Among ordinary chondrites, LL- or L-chondrites appear to be more likely than H-chondrites. No substantial regional difference was found on the asteroid surface, indicating its homogeneity in composition. PMID:16741109

Okada, Tatsuaki; Shirai, Kei; Yamamoto, Yukio; Arai, Takehiko; Ogawa, Kazunori; Hosono, Kozue; Kato, Manabu

2006-06-01

87

First X-ray Fluorescence MicroCT Results from Micrometeorites at SSRL  

SciTech Connect

X-ray fluorescence microCT (computed tomography) is a novel technique that allows non-destructive determination of the 3D distribution of chemical elements inside a sample. This is especially important in samples for which sectioning is undesirable either due to the risk of contamination or the requirement for further analysis by different characterization techniques. Developments made by third generation synchrotron facilities and laboratory X-ray focusing systems have made these kinds of measurements more attractive by significantly reducing scan times and beam size. First results from the x-ray fluorescence microCT experiments performed at SSRL beamline 6-2 are reported here. Beamline 6-2 is a 54 pole wiggler that uses a two mirror optical system for focusing the x-rays onto a virtual source slit which is then reimaged with a set of KB mirrors to a (2 x 4) {micro}{sup 2} beam spot. An energy dispersive fluorescence detector is located in plane at 90 degrees to the incident beam to reduce the scattering contribution. A PIN diode located behind the sample simultaneously measures the x-ray attenuation in the sample. Several porous micrometeorite samples were measured and the reconstructed element density distribution including self-absorption correction is presented. Ultimately, this system will be used to analyze particles from the coma of comet Wild-2 and fresh interstellar dust particles both of which were collected during the NASA Stardust mission.

Ignatyev, K; Huwig, K; Harvey, R; Ishii, H; Bradley, J; Luening, K; Brennan, S; Pianetta, P

2006-08-23

88

Quantification for 3D micro X-ray fluorescence  

NASA Astrophysics Data System (ADS)

3D micro X-ray fluorescence analysis (3D Micro-XRF) is a non-destructive method for the investigation of elemental compositions of specimens with which three-dimensionally resolved information can be obtained. This is rendered possible through the formation of a probing volume resulting from the overlap of a condensed X-ray beam and the acceptance of a polycapillary lens in front of an energy-dispersive detector. Various setup schemes have been developed in the last years, which can be divided into synchrotron instrumentation and X-ray tube based spectrometers. Established in 2003/2004 numerous applications have been published up until now. Quantification of data though is still a topic of considerable interest and has been reported only for limited number of publications. This review aims to give an overview of work on quantitative 3D Micro-XRF. As the method can be applied with adapted setups to a variety of analytical problems, quantification also has to be flexible and different schemes have been developed.

Mantouvalou, Ioanna; Malzer, Wolfgang; Kanngießer, Birgit

2012-11-01

89

Specimen preparation for x-ray fluorescence analysis of solutions  

SciTech Connect

Specimens for x-ray fluorescence analysis (XRFA) were prepared by adding dry gelatine (10%) to the analysis solution, homogenizing the mixture and cooling for 20 minutes. Thus, a compact resilient mass could be formed with the required shape and size; the roughness of the surface was determined by the roughness of the surface on which the specimen was formed, much the same as highly polished. Various calibration methods can be applied in the XRFA of a variety of materials if such specimens are used. 12 refs., 1 fig., 2 tabs.

Eksperiandova, L.P.; Spolnik, Z.M.; Blank, A.B.; Aliseychik, B.B. [Inst. for Single Crystals, Kharkov (Ukraine)

1995-12-31

90

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

Microsoft Academic Search

A quantitative study by x-ray diffraction, optical polarizing microscopy, and x-ray fluorescence spectrometry of fallout and ambient ash from three Mt. St. Helens eruptions has revealed a consistent picture of the mineralogical and elemental composition. The major components observed are amorphous glass, plagioclase of about An50 composition, minor amounts of quartz and other SiO2 polymorphs, as well as ferromagnesian constituents

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

1981-01-01

91

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

Microsoft Academic Search

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

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

1998-01-01

92

Quantum electrodynamics of the internal source x-ray holographies: Bremsstrahlung, fluorescence, and multiple-energy x-ray holography  

Microsoft Academic Search

Quantum electrodynamics (QED) is used to derive the differential cross sections measured in the three new experimental internal source ensemble x-ray holographies: bremsstrahlung (BXH), fluorescence (XFH), and multiple-energy (MEXH) x-ray holography. The polarization dependence of the BXH cross section is also obtained. For BXH, we study analytically and numerically the possible effects of the virtual photons and electrons which enter

Gerald A. Miller; Larry B. Sorensen

1997-01-01

93

Characterization and applications of a new tabletop confocal micro X-ray fluorescence setup  

Microsoft Academic Search

A tabletop confocal three-dimensional micro X-ray fluorescence (3D micro-XRF) setup was designed, based on polycapillary X-ray optics and a micro-focus X-ray source. This confocal setup consists of a polycapillary full lens to focus the incident beam and a polycapillary half lens to collect the X-ray fluorescence. The confocal volume was proved to be ellipsoidal. The full-width at half maximum (FWHM)

Xiaoyan Lin; Zhihong Wang; Tianxi Sun; Qiuli Pan; Xunliang Ding

2008-01-01

94

Synchrotron Radiation ?-X Ray Fluorescence on Multicellular Tumor Spheroids  

NASA Astrophysics Data System (ADS)

Synchrotron Radiation micro X-Ray Fluorescence (SR ?-XRF) was applied for the first time to map the trace element content on Multicellular Tumor Spheroids (MTS), i.e. human cell clusters used as an in vitro model for testing micrometastases responses to antitumoral drugs. In particular, immunotoxin molecules composed of a carrier protein (Transferrin) bound to a powerful cytotoxin (Ricin A), were here considered as representatives of a class of therapheutic macromolecules used in cancer theraphy. Spheroids included in polyacrylamide gel and placed inside quartz capillaries were studied at the ESRF ID22 beamline using a 15 keV monochromatic photon microbeam. Elemental maps (of Fe, Cu, Zn and Pb) on four groups of spheroids grown under different conditions were studied: untreated, treated only with the carrier molecule or with the toxin alone, and with the complete immunotoxin molecule (carrier+toxin). The results indicate that the distribution of Zn and, to some extent, Cu in the spheroid cells is homogeneous and independent of the treatment type. Total Reflection X-Ray Fluorescence (TR-XRF) was also applied to quantify the average trace element content in the spheroids. Future developments of the technique are finally outlined on the basis of these preliminary results.

Burattini, E.; Cinque, G.; Bellisola, G.; Fracasso, G.; Monti, F.; Colombatti, M.

2003-01-01

95

The X-ray Fluorescence Microscopy Beamline at the Australian Synchrotron  

SciTech Connect

A hard x-ray micro-nanoprobe has commenced operation at the Australian Synchrotron providing versatile x-ray fluorescence microscopy across an incident energy range from 4 to 25 keV. Two x-ray probes are used to collect {mu}-XRF and {mu}-XANES for elemental and chemical microanalysis: a Kirkpatrick-Baez mirror microprobe for micron resolution studies and a Fresnel zone plate nanoprobe capable of 60-nm resolution. Some unique aspects of the beamline design and operation are discussed. An advanced energy dispersive x-ray fluorescence detection scheme named Maia has been developed for the beamline, which enables ultrafast x-ray fluorescence microscopy.

Paterson, D.; Jonge, M. D. de; Howard, D. L.; Lewis, W.; McKinlay, J.; Starritt, A.; Kusel, M. [Australian Synchrotron, Clayton, VIC 3168 (Australia); Ryan, C. G.; Kirkham, R.; Moorhead, G. [CSIRO, Clayton VIC, 3168 (Australia); Siddons, D. P. [Instrumentation Division, Brookhaven National Laboratory, Brookhaven, NY (United States)

2011-09-09

96

Quantum electrodynamics of the internal source x-ray holographies: Bremsstrahlung, fluorescence, and multiple-energy x-ray holography  

SciTech Connect

Quantum electrodynamics (QED) is used to derive the differential cross sections measured in the three new experimental internal source ensemble x-ray holographies: bremsstrahlung (BXH), fluorescence (XFH), and multiple-energy (MEXH) x-ray holography. The polarization dependence of the BXH cross section is also obtained. For BXH, we study analytically and numerically the possible effects of the virtual photons and electrons which enter QED calculations in summing over the intermediate states. For the low photon and electron energies used in the current experiments, we show that the virtual intermediate states produce only very small effects. This is because the uncertainty principle limits the distance that the virtual particles can propagate to be much shorter than the separation between the regions of high electron density in the adjacent atoms. We also find that using the asymptotic form of the scattering wave function causes about a 5{endash}10{percent} error for near forward scattering. {copyright} {ital 1997} {ital The American Physical Society}

Miller, G.A.; Sorensen, L.B. [Department of Physics, University of Washington, Seattle, Washington 98195 (United States)] [Department of Physics, University of Washington, Seattle, Washington 98195 (United States)

1997-08-01

97

Development of a micro-X-ray fluorescence system based on polycapillary X-ray optics for non-destructive analysis of archaeological objects  

Microsoft Academic Search

A new micro-X-ray fluorescence (micro-XRF) system based on rotating anode X-ray generator and polycapillary X-ray optics has been set up in XOL Lab, BNU, China, in order to be used for analysis of archaeological objects. The polycapillary X-ray optics used here can focus the primary X-ray beam down to tens of micrometers in diameter that allows for non-destructive and local

Lin Cheng; Xunliang Ding; Zhiguo Liu; Qiuli Pan; Xuelian Chu

2007-01-01

98

In vivo X-ray fluorescence (XRF) measurement of uranium in bone.  

PubMed

This study investigates the applicability of X-ray fluorescence (XRF) to measuring bone uranium concentrations, using a 57Co source to excite the uranium X-rays, with the source and detector in an approximate 180 degrees backscatter geometry relative to the sample position. It is demonstrated, by experiment and Monte Carlo simulation, that the X-ray to coherent peak ratio is linearly related to concentration and is independent of variations in source-sample geometry, thickness of overlying tissue and tibia size. Preliminary in vivo measurements indicate a minimum detectable concentration (MDC) of approximately 20 micrograms/g, which may not be sufficiently sensitive for monitoring occupational workers. However, a larger study of occupationally exposed individuals as well as work with subjects with known significant accidental uranium exposures is necessary to assess the clinical usefulness of this system. PMID:9569588

O'Meara, J M; Chettle, D R; McNeill, F E; Webber, C E

1998-01-01

99

The Application of X-Ray Fluorescence in Meteorite Investigation.  

NASA Astrophysics Data System (ADS)

The project explored the use of X-Ray Fluorescence (XRF) in determining the composition and classification of meteoritic samples. Radioactive sources of Fe-55, Cm-244, and Am-241 were used to fluoresce the meteorite samples. A liquid nitrogen cooled ORTEC Si(Li) detector, with a 0.3 mil Be window, was used to detect the photons fluoresced from the sample. The data was collected and analyzed by a pentium based PCA III data acquisition system. Efficiency of the detector was determined by (i) measuring calibrated radioactive sources and by (ii) determining the attenuation of photons through the various layers of the detector. Determining the suitability of source and duration of fluorescence was an important part of detecting trace elements present in the meteorite samples. The Fe-55 source was found to be the best source to detect the silicates present in stony meteorites. While the Cm-244 source was found to be the best at detecting iron and nickel in the iron meteorites.

Sheesley, Christopher; Mehta, Rahul

1996-03-01

100

X-ray fluorescence surface contaminant analyzer: A feasibility study  

NASA Technical Reports Server (NTRS)

The bonding of liner material to the inner metal surfaces of solid rocket booster cases is adversely affected by minute amounts of impurities on the metal surface. Suitable non-destructive methods currently used for detecting these surface contaminants do not provide the means of identifying their elemental composition. The feasibility of using isotopic source excited energy dispersive X-ray fluorescence as a possible technique for elemental analysis of such contaminants is investigated. A survey is made of the elemental compositions of both D-6ac steel, a common construction material for the booster cases, and Conoco HD-2 grease, a common surface contamination. Source and detector choices that maximize signal to noise ratio in a Recessed Source Geometry are made. A Monte Carlo simulation is then made of the optimized device incorporating the latest available X-ray constants at the energy of the chosen source to determine the device's response to a D-6ac steel surface contained with Conoco HD-2 grease.

Eldridge, Hudson B.

1988-01-01

101

ANS hard X-ray experiment development program. [emission from X-ray sources  

NASA Technical Reports Server (NTRS)

The hard X-ray (HXX) experiment is one of three experiments included in the Dutch Astronomical Netherlands Satellite, which was launched into orbit on 30 August 1974. The overall objective of the HXX experiment is the detailed study of the emission from known X-ray sources over the energy range 1.5-30keV. The instrument is capable of the following measurements: (1) spectral content over the full energy range with an energy resolution of approximately 20% and time resolution down to 4 seconds; (2) source time variability down to 4 milliseconds; (3) silicon emission lines at 1.86 and 2.00keV; (4) source location to a limit of one arc minute in ecliptic latitude; and (5) spatial structure with angular resolution of the arc minutes. Scientific aspects of experiment, engineering design and implementation of the experiment, and program history are included.

Parsignault, D.; Gursky, H.; Frank, R.; Kubierschky, K.; Austin, G.; Paganetti, R.; Bawdekar, V.

1974-01-01

102

Aluminum impurities in silicon: Investigation of x-ray Raman scattering in total reflection x-ray fluorescence spectroscopy  

NASA Astrophysics Data System (ADS)

Total reflection x-ray fluorescence using synchrotron radiation from the Stanford Synchrotron Radiation Laboratory has been used to study Al impurities on Si wafer surfaces. For primary excitation energies below the Si K absorption edge an inelastic resonance scattering due to resonant x-ray Raman scattering is observed. This scattering dominates the background behavior of the Al K fluorescence line, and consequently limits the achievable sensitivity for detection of Al surface contaminants. The energy and angle dependence of the resonant x-ray Raman scattering has been investigated to determine the experimental conditions for which the highest sensitivity for Al can be achieved. We find that for a precise determination of the achievable sensitivity, the specific shape of the continuous Raman background has to be taken into account. Our calculations demonstrate a minimum detection limit for Al of 6×109 atoms/cm2 for a 10 000 s count time.

Baur, K.; Kerner, J.; Brennan, S.; Singh, A.; Pianetta, P.

2000-10-01

103

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

Microsoft Academic Search

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

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

2011-01-01

104

X-Ray Fluorescence with High-Resolution Superconducting Tunnel Junction X-Ray Detectors  

Microsoft Academic Search

We are developing X-ray detectors based on superconducting-insulating superconducting tunnel junctions for high-resolution spectroscopy in the soft x-ray regime (E = 100 eV to 1000 eV). These detectors offer high energy resolution simultaneously with high count rate, broad bandwidth, and high quantum efficiency. The energy resolution ranges from DeltaE = 3.5 eV (FWHM) to about 10 eV depending on the

Carl A. Mears

1998-01-01

105

Materials characterization using micro-x-ray fluorescence elemental imaging.  

SciTech Connect

Materials characterization continues to be a key challenge in a variety of programs. Although bulk elemental composition provides overall concentration of both major and trace elements, the distribution of these elements both on micro and macro scales can determine the performance and ultimately the physical properties of the materials. Hence elemental imaging can provide a new level of information for major and in some cases bulk trace concentrations of elements. Micro X-ray fluorescence (MXRF) offers unique capabilities in terms of elemental imaging. This approach is based on a meso scale level of resolution around 50 micrometer X-ray spot size. When coupled with a moveable stage, specimens several inches on a side can be imaged with surprising detail. In most instances, qualitative images are sufficient to illustrate the elemental heterogeneity. This information can then be used to determine if the material meets the desired physical characteristics and whether this is due to the observed heterogeneity or in spite of it. Several examples of elemental imaging will be presented. These will include the aging of polymers and the effects of residual organotin catalyst. The tin can be imaged using MXRF and has been show to be mobile within the polymeric material over time. Corrosion is a serious issue throughout the industrial world. A specific example of chloride attack on a metal, which creates problems in waste storage. Finally, MXRF used in high throughput screening in the development of novel peptide receptors will be shown. The advantage of MXRF is that no fluorescent tags need be added to the target molecules. This insures the unhindered interaction of the target molecules and allows for additional characterization using molecular spectroscopic techniques.

Havrilla, G. J. (George J.); Miller, T. C. (Thomasin C.); Joseph, M. R. (Martha R.)

2002-01-01

106

X-ray laser `` oscillator-amplifier`` experiments  

SciTech Connect

We present results from experiments directed toward increasing the degree of transverse coherence in x-ray laser beams. We have concentrated on the neon-like yttrium (Z=39) collisionally-pumped x-ray laser as the test system for these studies because of its unique combination of brightness, monochromaticity, and high-reflectivity optics availability. Attempts at improving laser performance using proximate feedback optics failed. Modest success has been found to date in ``double foil`` experiments, involving two x-ray lasers spatially separated by 29 cm and shot sequentially in an ``oscillator-amplifier`` configuration.

Shimkaveg, G.M.; Carter, M.R.; Young, B.K.F.; Walling, R.S.; Osterheld, A.L.; Trebes, J.E.; London, R.A.; Ratowsky, R.P.; Stewart, R.E. [Lawrence Livermore National Lab., CA (United States); Craxton, R.S. [Rochester Univ., NY (United States). Lab. for Laser Energetics

1993-03-19

107

Sub-micron Hard X-ray Fluorescence Imaging of Synthetic Elements  

PubMed Central

Synchrotron-based X-ray fluorescence microscopy (SXFM) using hard X-rays focused into sub-micron spots is a powerful technique for elemental quantification and mapping, as well as microspectroscopic measurement such as ?-XANES (X-ray absorption near edge structure). We have used SXFM to image and simultaneously quantify the transuranic element plutonium at the L3 or L2 edge as well as lighter biologically essential elements in individual rat pheochromocytoma (PC12) cells after exposure to the long-lived plutonium isotope 242Pu. Elemental maps reveal that plutonium localizes principally in the cytoplasm of the cells and avoids the cell nucleus, which is marked by the highest concentrations of phosphorus and zinc, under the conditions of our experiments. The minimum detection limit under typical acquisition conditions for an average 202 ?m2 cell is 1.4 fg Pu/cell or 2.9 × 10?20 moles Pu/?m2, which is similar to the detection limit of K-edge SXFM of transition metals at 10 keV. Copper electron microscopy grids were used to avoid interference from gold X-ray emissions, but traces of strontium present in naturally occurring calcium can still interfere with plutonium detection using its L? X-ray emission.

Jensen, Mark P.; Aryal, Baikuntha P.; Gorman-Lewis, Drew; Paunesku, Tatjana; Lai, Barry; Vogt, Stefan; Woloschak, Gayle E.

2013-01-01

108

Effect of regolith on planetary X-ray fluorescence spectroscopy: laboratory and numerical studies  

Microsoft Academic Search

Fluorescent X-rays from the surfaces of airless planetary bodies in the inner solar system have been measured by instruments on several spacecraft. X-ray emission follows photoionisation by incident solar X-rays and charged particles and reveals the elemental composition of the surface. Analyses of X-ray spectra obtained by orbiting spacecraft, use the relative intensities of elemental emission lines (e.g., Ca\\/Si, Fe\\/Si)

Jyri Naranen; James Carpenter; Hannu Parviainen; Karri Muinonen

2008-01-01

109

Characterization of a pulsed X-ray source for fluorescent lifetime measurements  

Microsoft Academic Search

To search for new, fast, inorganic scintillators, we have developed a bench-top pulsed X-ray source for determining fluorescent lifetimes and wavelengths of compounds in crystal or powdered form. This source uses a light-excited X-ray tube which produces X-rays when light from a laser diode strikes its photocathode. The X-ray tube has a tungsten anode, a beryllium exit window, a 30

S. C. Blankespoor; S. E. Derenzo; W. W. Moses; C. S. Rossington; M. Ito; K. Oba

1994-01-01

110

Interference of fluorescence x-rays and coherent excitation of core levels  

SciTech Connect

The question of coherence in inelastic x-ray absorption and fluorescence processes among identical interacting atoms is studied using a simple diatomic model. Conditions for the coherence are discussed in terms of energy scales, such as the core hole life-time, instrument energy resolutions, and the splitting of the electronic levels. As in the classical Young double-slit experiment, the primary requirement is that it be impossible to determine which atom has undergone the excitation-decay process.

Ma, Y. [Washington Univ., Seattle, WA (United States). Dept. of Physics]|[Pacific Northwest Lab., Richland, WA (United States); Blume, M. [Brookhaven National Lab., Upton, NY (United States)

1994-08-01

111

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

Microsoft Academic Search

X-ray fluorescence (XRF) and total-reflection X-ray fluorescence (TXRF) techniques suited well for a multi-element determination of K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr in some Syrian medicinal plant species. The accuracy and the precision of both techniques were verified by analyzing the Standard Reference Materials (SRM) peach-1547 and apple leaves-1515. A good agreement between the measured concentrations of

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

2009-01-01

112

Fast X-Ray Fluorescence Microtomography of Hydrated Biological Samples  

PubMed Central

Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples.

Lombi, Enzo; de Jonge, Martin D.; Donner, Erica; Kopittke, Peter M.; Howard, Daryl L.; Kirkham, Robin; Ryan, Chris G.; Paterson, David

2011-01-01

113

X-ray lasing - The experiments  

SciTech Connect

The Novette laser is used to produce a population inversion in an exploding foil plasma, and substantial amplification of spontaneous emission at soft-x-ray wavelengths is demonstrated. Targets consist of thin selenium or yttrium foils deposited on one side of a Formvar substrate. The on-axis emission spectrum was measured by a microchannel-plate grazing-incidence spectrometer (MCPIGS) and a transmission-grating streak spectrometer (TGSS). A second MCPIGS, placed at an angle of 77 degrees to the long axis, was used to confirm the anisotropy of the amplification. The amplification of at least four 3p to 3s transitions was observed, the largest gain being detected for the J = 2 to J = 1 lines at wavelengths of 20.9 nm (59 eV) and 20.6 nm (60 eV) in selenium and at 15.5 nm (80 eV) in yttrium. The optimum amplification occurred at a target thickness of 75 nm and a pulse length of 450 ps or longer. By varying the target lengths, the exponential growth with increasing length that characterizes stimulated emission was observed. It is estimated that lasing at 8 nm wavelengths is attainable with the present collision excitation scheme. 6 references.

Not Available

1985-11-01

114

X-ray lasing - The experiments  

NASA Astrophysics Data System (ADS)

The Novette laser is used to produce a population inversion in an exploding foil plasma, and substantial amplification of spontaneous emission at soft-X-ray wavelengths is demonstrated. Targets consist of thin selenium or yttrium foils deposited on one side of a Formvar substrate. The on-axis emission spectrum was measured by a microchannel-plate grazing-incidence spectrometer (MCPIGS) and a transmission-grating streak spectrometer (TGSS). A second MCPIGS, placed at an angle of 77 degrees to the long axis, was used to confirm the anisotropy of the amplification. The amplification of at least four 3p to 3s transitions was observed, the largest gain being detected for the J = 2 to J = 1 lines at wavelengths of 20.9 nm (59 eV) and 20.6 nm (60 eV) in selenium and at 15.5 nm (80 eV) in yttrium. The optimum amplification occurred at a target thickness of 75 nm and a pulse length of 450 ps or longer. By varying the target lengths, the exponential growth with increasing length that characterizes stimulated emission was observed. It is estimated that lasing at 8 nm wavelengths is attainable with the present collision excitation scheme.

1985-11-01

115

Investigation of a Tabletop Confocal Micro X-Ray Fluorescence Setup  

Microsoft Academic Search

A new tabletop confocal micro x-ray fluorescence setup with an MCBM 50-0.6B x-ray tube is assembled. The confocal micro x-ray fluorescence setup includes two lenses, a polycapillary full lens in the excitation channel and a polycapillary half lens in the detection channel. A Ni-Cr wire in diameter 25 ?m is used to investigate the FWHM of three-dimensional confocal volume. A

Xiao-Yan Lin; Zhi-Hong Wang; Xue-Lian Chu; Tian-Xi Sun; Xun-Liang Ding

2007-01-01

116

Flow method and apparatus for screening chemicals using micro x-ray fluorescence  

DOEpatents

Method and apparatus for screening chemicals using micro x-ray fluorescence. A method for screening a mixture of potential pharmaceutical chemicals for binding to at least one target binder involves flow separating a solution of chemicals and target binders into separated components, exposing them to an x-ray excitation beam, detecting x-ray fluorescence signals from the components, and determining from the signals whether or not a binding event between a chemical and target binder has occurred.

Warner, Benjamin P. (Los Alamos, NM) [Los Alamos, NM; Havrilla, George J. (Los Alamos, NM) [Los Alamos, NM; Miller, Thomasin C. (Bartlesville, OK) [Bartlesville, OK; Lewis, Cris (Los Alamos, NM) [Los Alamos, NM; Mahan, Cynthia A. (Los Alamos, NM) [Los Alamos, NM; Wells, Cyndi A. (Los Alamos, NM) [Los Alamos, NM

2011-04-26

117

Flow method and apparatus for screening chemicals using micro x-ray fluorescence  

DOEpatents

Method and apparatus for screening chemicals using micro x-ray fluorescence. A method for screening a mixture of potential pharmaceutical chemicals for binding to at least one target binder involves flow-separating a solution of chemicals and target binders into separated components, exposing them to an x-ray excitation beam, detecting x-ray fluorescence signals from the components, and determining from the signals whether or not a binding event between a chemical and target binder has occurred.

Warner, Benjamin P. (Los Alamos, NM); Havrilla, George J. (Los Alamos, NM); Miller, Thomasin C. (Bartlesville, OK); Lewis, Cris (Los Alamos, NM); Mahan, Cynthia A. (Los Alamos, NM); Wells, Cyndi A. (Los Alamos, NM)

2009-04-14

118

Performances of capillary X-ray optics for confocal three-dimensional micro-X-ray fluorescence technology  

NASA Astrophysics Data System (ADS)

The performances of capillary X-ray optics (CXRO) for confocal three-dimensional micro-X-ray fluorescence (3D Micro-XRF) technology are presented. In particular, the energy dependence of the collecting angle and input focal spot size of the polycapillary parallel X-ray lens (PPXRL), and the energy dependence of spatial resolution of the confocal 3D Micro-XRF spectrometer based on the CXRO are reported. In order to obtain the input focal spot size of the PPXRL, the source scan method was used. The size of the input focal spot of the PPXRL was 25.5 ?m at 13 keV, and it was close to that of the output focal spot of a polycapillary focusing X-ray lens (PFXRL) at the same energy. The collecting angle of the PPXRL was 110 mrad at 10 keV, and it decreased with the increasing energies. The depth spatial resolution of the confocal 3D Micro-XRF spectrometer based on the CXRO was 29.3 ?m at 17 keV, and it decreased with the increasing energies. The minimal detection limit of this confocal 3D Micro-XRF spectrometer was 101 ppm for the Ti-K?, when the operating voltage and current of the Mo X-ray tube were 36.0 kV and 800.0 ?A, respectively.

Sun, Tianxi; Liu, Zhiguo; Li, Yude; Zhu, Guanghua; Lin, Xiaoyan; Luo, Ping; Pan, Qiuli; Liu, Hui; Teng, Yuepeng; Yang, Ke; Ding, Xunliang

2009-07-01

119

Dendrimer-folate-copper conjugates as bioprobes for synchrotron X-ray fluorescence imaging.  

PubMed

We present a bioprobe for synchrotron X-ray fluorescence imaging based on dendrimer-folate-copper conjugates. The metal nanoclusters within a dendrimer exhibit excellent FR-targeting properties in KB cells. It could be used as a new multifunction bioprobe for synchrotron X-ray fluorescence mapping. PMID:24072098

Zhang, Yuanqing; Xu, Xiaoping; Wang, Lu; Lin, Jun; Zhu, Ying; Guo, Zhi; Sun, Yanhong; Wang, Hua; Zhao, Yun; Tai, Renzhong; Yu, Xiaohan; Fan, Chunhai; Huang, Qing

2013-11-14

120

X-ray Fluorescence Analysis of Powdered As x Se 100 – x Samples  

Microsoft Academic Search

A procedure was developed for the X-ray fluorescence determination of components in powdered samples of AsxSe100 – x, and its performance characteristics were determined. The relative standard deviation was 0.15% for the major components. The results of X-ray fluorescence analysis were in good agreement with data of atomic absorption spectroscopy.

N. I. Mashin; R. V. Lebedeva; A. N. Tumanova

2004-01-01

121

In situ measurements of colloid transport and retention using synchrotron X-ray fluorescence  

Microsoft Academic Search

The physics regarding the retention and mobilization of colloids in saturated and unsaturated conditions remains poorly understood, partially because of the inability to measure colloid concentrations in situ. In this study, we attached Cd+2 ions to clay colloids and used synchrotron X rays to cause the Cd to fluoresce. By measuring the fluorescence and attenuation of the X rays we

David A. DiCarlo; Yuniati Zevi; Annette Dathe; Shree Giri; Bin Gao; Tammo S. Steenhuis

2006-01-01

122

Lunar X-ray fluorescence observations by the Chandrayaan-1 X-ray Spectrometer (C1XS): Results from the nearside southern highlands  

Microsoft Academic Search

The Chandrayaan-1 X-ray Spectrometer (C1XS) flown on-board the first Indian lunar mission Chandrayaan-1, measured X-ray fluorescence spectra during several episodes of solar flares during its operational period of ?9months. The accompanying X-ray Solar Monitor (XSM) provided simultaneous spectra of solar X-rays incident on the Moon which are essential to derive elemental chemistry. In this paper, we present the surface abundances

S. Narendranath; P. S. Athiray; P. Sreekumar; B. J. Kellett; L. Alha; C. J. Howe; K. H. Joy; M. Grande; J. Huovelin; I. A. Crawford; U. Unnikrishnan; S. Lalita; S. Subramaniam; S. Z. Weider; L. R. Nittler; O. Gasnault; D. Rothery; V. A. Fernandes; N. Bhandari; J. N. Goswami; M. A. Wieczorek

2011-01-01

123

In vivo X-ray fluorescence of lead in bone using K X-ray excitation with 109Cd sources: Radiation dosimetry studies  

Microsoft Academic Search

Independent experiments have been performed at two centers, to evaluate the dosimetric properties of their respective Ā¹Ā°ā¹Cd K X-ray fluorescence (XRF) bone lead measurement systems. Measurements were made of the dose to several points on the skin of the lower leg, at the surface of the tibia, in the red marrow tibia cavity, at the midcalf, and in the abdominal

A. C. Todd; F. E. McNeill; J. E. Palethorpe; D. E. Peach; D. R. Chettle; M. J. Tobin; S. J. Strosko; J. C. Rosen

1992-01-01

124

Portable x-ray fluorescence spectrometer. Innovative technology summary report  

SciTech Connect

This report describes the application of portable X-ray fluorescence (XRF) spectrometry to characterize materials related to deactivation and decommissioning (D and D) of contaminated facilities. Two portable XRF instruments manufactured by TN Spectrace were used in a technology evaluation as part of the Large-Scale Demonstration Project (LSDP) held at the Chicago Pile-5 Research Reactor (CP-5) located at Argonne National Laboratory (ANL). The LSDP is sponsored by the US Department of Energy (DOE), Office of Science and Technology, Deactivation and Decommissioning Focus Are (DDFA). The objective of the LSDP is to demonstrate innovative technologies or technology applications potentially beneficial to the D and D of contaminated facilities. The portable XRF technology offers several potential benefits for rapid characterization of facility components and contaminants, including significant cost reduction, fast turnaround time,a nd virtually no secondary waste. Field work for the demonstration of the portable XRF technology was performed from August 28--September 3, 1996 and October 30--December 13, 1996.

NONE

1998-12-01

125

Bone lead measured by X-ray fluorescence: epidemiologic methods.  

PubMed Central

In vivo X-ray fluorescence (XRF) measurement of bone lead concentration (XRF) has emerged as an important technique for future epidemiological studies of long-term toxicity. Several issues germane to epidemiologic methodology need to be addressed, however. First, sources of variability in measurements of bone lead need to be quantified, including imprecision related to the physical measurement itself and the variability of lead deposition over the two main compartments of bones (cortical vs. trabecular) and within each compartment. Imprecision related to the physical measurement can be estimated for each individual measurement based on the variability of the signal and background. Second, approaches to low-level data need to be debated. We argue for using the minimal detection limit (MDL) to compare instruments and interpret individual measurements; however, with regard to epidemiologic studies, we would abandon the MDL in favor of using all point estimates. In analyses using bone lead as an independent variable, statistical techniques can be used to adjust regression estimates based on estimates of measurement uncertainty and bone lead variability. Third, factors that can be expected to modify the relationship between bone lead and toxicity such as gravida history, endocrinological states, nutrition, and other important influences on bone metabolism, need to be identified and measured in epidemiologic studies. By addressing these issues, investigators will be able to maximize the utility of XRF measurements in environmental epidemiologic studies. Images Figure 2.

Hu, H; Aro, A; Rotnitzky, A

1995-01-01

126

High-throughput screening with micro-x-ray fluorescence  

NASA Astrophysics Data System (ADS)

Micro-x-ray fluorescence (MXRF) is a useful characterization tool for high-throughput screening of combinatorial libraries. Due to the increasing threat of use of chemical warfare (CW) agents both in military actions and against civilians by terrorist extremists, there is a strong push to improve existing methods and develop means for the detection of a broad spectrum of CW agents in a minimal amount of time to increase national security. This paper describes a combinatorial high-throughput screening technique for CW receptor discovery to aid in sensor development. MXRF can screen materials for elemental composition at the mesoscale level (tens to hundreds of micrometers). The key aspect of this work is the use of commercial MXRF instrumentation coupled with the inherent heteroatom elements within the target molecules of the combinatorial reaction to provide rapid and specific identification of lead species. The method is demonstrated by screening an 11-mer oligopeptide library for selective binding of the degradation products of the nerve agent VX. The identified oligopeptides can be used as selective molecular receptors for sensor development. The MXRF screening method is nondestructive, requires minimal sample preparation or special tags for analysis, and the screening time depends on the desired sensitivity.

Havrilla, George J.; Miller, Thomasin C.

2005-06-01

127

X-Ray Fluorescence Measurements of 412 Inorganic Compounds  

SciTech Connect

In a search for new, fast, inorganic scintillators, 412 inorganic compounds have been exposed to 0.5-ns pulses of 20-keV X-rays and their fluorescent emissions have been measured. Most of these compounds were dense (>4 g/cm{sup 3}), contained heavy cations such as Pb, Bi, Ba, or a rare-earth element, and anions such as O, F, Cl, Br, I, CO{sub 3}, SO{sub 4} and PO{sub 4}. About half were undoped compounds and half contained 0.1% to 10% rare-earth dopants. Standard scintillators such as BaF{sub 2} and BGO were included for reference. The authors report total luminosities and fitted exponential decay times and percentages for 97 compounds having either a luminosity >40% of BGO, or an initial photon intensity greater than BGO, or a component decay time <1 ns. Emission wavelengths are listed for 53 of these compounds. Significant fast emissions were seen from Y{sub 2}SiO{sub 5}:Ce, CeCl{sub 3}, BaCl{sub 2}, PbSO{sub 4}, and LuPO{sub 4}:Ce. Other less luminous compounds, i.e., Yb{sub 2}O{sub 3}, CuI, CuBr, and BiPO{sub 4}:Gd, exhibited components with shorter decay times than ZnO:Ga and BaF{sub 2}.

Derenzo, S. E. [Lawrence Berkeley National Laboratory (LBNL); Moses, W. W. [Lawrence Berkeley National Laboratory (LBNL); Cahoon, J. L. [Lawrence Berkeley National Laboratory (LBNL); DeVol, T. A. [University of Michigan; Boatner, Lynn A [ORNL

1991-01-01

128

Continuous Flow Cryostat for X-Ray Fluorescence  

SciTech Connect

A continuous Helium flow cryostat was designed and built by Cryovac GMbH to specifications given by ESRF beamline ID26. The beamline has constructed a high energy resolution X-ray emission spectrometer using multiple spherically bent analyser crystals, together with the sample and detector on a vertical Rowland circle. The double shrouded cryostat has a low profile designed to fit into the spectrometer setup, the lowest detector position allows for a Bragg angle of 85 degrees with a 1 meter diameter Rowland circle. The cryostat has a temperature range of 5 to 300 Kelvin on the sample holder which is cooled by static Helium exchange gas. The cryostat has triple windows for beam entrance, transmission and fluorescence; the latter offers an opening angle of 80 degrees horizontally and 50 degrees vertically. The cryostat can be configured to work in two different operation modes: translation or rotation. The translation mode offers a displacement of 50 mm to accommodate multiple samples on the sample holder. The rotation mode is used for polarisation studies on single crystals.We show recent results obtained on Chromium containing molecular complexes; data collection was done at a temperature of 10 Kelvin to avoid radiation damage.

Weng, T.-C.; Linden, Peter J. E. M. van der; Glatzel, Pieter; Lapras, Christophe [ESRF, 6 rue Jules Horowitz, F-38043 Grenoble (France); Krzyzowski, Michael [CryoVac GMbH and Co KG, Heuserweg 14, D-53482 Troisdorf (Germany)

2010-06-23

129

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

SciTech Connect

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

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

2013-06-15

130

High spatial resolution hard X-ray microscope using X-ray refractive lens and phase contrast imaging experiments  

Microsoft Academic Search

A high spatial resolution X-ray microscope was constructed using an X-ray refractive lens as an objective. The spatial resolution was tested using 18keV X-ray. A 0.4?m line and 0.4?m space tantalum test pattern was successfully resolved. Using the similar setup with the addition of a phase plate, a Zernike type phase-contrast microscopy experiment was carried out for the phase retrieval

Y. Kohmura; K. Okada; A. Takeuchi; H. Takano; Y. Suzuki; T. Ishikawa; T. Ohigashi; H. Yokosuka

2001-01-01

131

Characterization and applications of a new tabletop confocal micro X-ray fluorescence setup  

NASA Astrophysics Data System (ADS)

A tabletop confocal three-dimensional micro X-ray fluorescence (3D micro-XRF) setup was designed, based on polycapillary X-ray optics and a micro-focus X-ray source. This confocal setup consists of a polycapillary full lens to focus the incident beam and a polycapillary half lens to collect the X-ray fluorescence. The confocal volume was proved to be ellipsoidal. The full-width at half maximum (FWHM) of the confocal volume in three directions were measured with a "knife edge" scan method to obtain the spatial resolution of the confocal setup. The structure of multilayer samples was studied using the depth scan technique.

Lin, Xiaoyan; Wang, Zhihong; Sun, Tianxi; Pan, Qiuli; Ding, Xunliang

2008-06-01

132

Simultaneous Detection of X-Ray Fluorescence and Conversion Electrons for Depth Selective XAFS Analysis  

SciTech Connect

An apparatus has been developed, which enables us to monitor both x-ray fluorescence yield (XFY) and conversion electron yield (CEY) from a sample. The apparatus has been installed to the BL11 of HSRC, and its basic performance has been evaluated. The detection limit of X-ray fluorescence analysis is 1.5 ppm for Ca and 6.6 ppm for S when the incident x-ray energy is optimized just above the absorption edge energy. The probing depth of the CEY method is estimated to be 4.0 nm for Ag thin films around Ag LIII edge while the escape depth of the x-ray fluorescence is more than 1 {mu}m The near surface sensitivity of the CEY is advantageous for XAFS measurements because x-ray fluorescence mode may suffer self-absorption-effects.

Hayakawa, Shinjiro; Makiyama, Yusuke; Esumi, Taku; Hirokawa, Takeshi [Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Hiroshima (Japan); Qiao, Shan; Namatame, Hirofumi [Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, Hiroshima, (Japan); Morikawa, Atsushi; Tohno, Susumu [Graduate School of Energy Science, Kyoto University, Kyoto (Japan)

2007-02-02

133

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

Microsoft Academic Search

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

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

1987-01-01

134

X-Ray Fluorescence Analysis of a Gold Ibex and other Artifacts from Akrotiri  

Microsoft Academic Search

The in-situ X-ray fluorescence analysis (XRF) of ancient artifacts from the excavation area of Akrotiri, Greece was performed using novel instrumentation composed of a portable silicon PIN thermoelectrically cooled X-ray detector, a miniature X-ray source, and portable data acquisition devices. The main objective of the analyses was to explore the potential of the XRF technique to provide answers to a

T. Pantazis; A. G. Karydas; A. Vlachopoulos; P. Nomikos; M. Dinsmoree

135

Crystal cavity resonance for hard x rays: A diffraction experiment  

SciTech Connect

We report the details of the recent x-ray back diffraction experiments, in which interference fringes due to x-ray cavity resonance are unambiguously observed. The Fabry-Perot type cavities, the tested crystal devices of reflectivity R{approx_equal}0.5 and finesse F{approx_equal}2.3, consist of monolithic two-plate and eight-plate silicon crystals. They were prepared by using x-ray lithographic techniques. The thicknesses of the crystal plates and the gaps between the two adjacent plates are a few tens to hundreds {mu}m. The (12 4 0) back reflection and synchrotron x-radiation of energy resolution {delta}E=0.36 meV at 14.4388 keV are employed. Interference fringes in angle- and photon-energy scans for two-plate and eight-plate cavities are shown. Considerations on the temporal and spatial coherence for observable resonance interference fringes using synchrotron x-rays are presented. The details about the accompanied simultaneous 24-beam diffraction in relation to x-ray photon energy are also described.

Chang, S.-L. [Department of Physics, National Tsing Hua University (NTHU), Hsinchu, Taiwan, 300 (China); National Synchrotron Radiation Research Center (NSRRC), Hsinchu, Taiwan, 300 (China); Stetsko, Yu. P.; Tang, M.-T.; Shew, B.-Y. [National Synchrotron Radiation Research Center (NSRRC), Hsinchu, Taiwan, 300 (China); Lee, Y.-R.; Sun, W.-H.; Wu, H.-H.; Kuo, T.-T.; Chen, S.-Y.; Chang, Y.-Y.; Shy, J.-T. [Department of Physics, National Tsing Hua University (NTHU), Hsinchu, Taiwan, 300 (China); Yabashi, M. [Spring-8/JASRI, Mikazuki, Hyogo 679-5198 (Japan); Ishikawa, T. [Spring-8/JASRI, Mikazuki, Hyogo 679-5198 (Japan); Spring-8/RIKEN, Mikazuki, Hyogo 679-5148 (Japan); Lin, Y.-H. [Scientific Instrumentation Research and Development Center, Hsinchu, Taiwan, 300 (China); Tamasaku, K.; Miwa, D. [Spring-8/RIKEN, Mikazuki, Hyogo 679-5148 (Japan)

2006-10-01

136

[Methods of detector response function establishment in X-ray fluorescence spectra analysis].  

PubMed

During the measurement and analysis process of X-ray fluorescence spectra, it is very helpful to improve the analyze speed, accuracy and automaticity of X-ray fluorescence spectra analysis by establishing detector response function(DRF), which represents the shape of full energy peak and can provide former basic data for subsequent X-ray analysis technique. For the theory and model of semiconductor DRF in X-ray energy spectrum measurements, methods of three typical detector response function model establishment, key parameters of full energy peak standard deviation and Fano factor calculation, etc. are discussed, and meanwhile, the summarization and contrast of existing studies are shown in this paper. Finally, the suggestion for modeling methods of DRF in X-ray fluorescence spectra measurements is provided. PMID:23387190

Li, Zhe; Tuo, Xian-Guo; Yang, Jian-Bo; Liu, Ming-Zhe; Cheng, Yi; Wang, Lei; Zhou, Jian-Bin

2012-11-01

137

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

Microsoft Academic Search

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

Wheeler

1982-01-01

138

Development and applications of an epifluorescence module for synchrotron x-ray fluorescence microprobe imaging  

Microsoft Academic Search

Synchrotron x-ray fluorescence (XRF) microprobe is a valuable analysis tool for imaging trace element composition in situ at a resolution of a few microns. Frequently, epifluorescence microscopy is beneficial for identifying the region of interest. To date, combining epifluorescence microscopy with x-ray microprobe has involved analyses with two different microscopes. We report the development of an epifluorescence module that is

Lisa M. Miller; Randy J. Smith; Meghan E. Ruppel; Cassandra H. Ott; Antonio Lanzirotti

2005-01-01

139

Trace element abundance determinations by Synchrotron X Ray Fluorescence (SXRF) on returned comet nucleus mineral grains  

Microsoft Academic Search

Trace element analyses were performed on bulk cosmic dust particles by Proton Induced X Ray Emission (PIXE) and Synchrotron X Ray Fluorescence (SXRF). When present at or near chondritic abundances the trace elements K, Ti, Cr, Mn, Cu, Zn, Ga, Ge, Se, and Br are presently detectable by SXRF in particles of 20 micron diameter. Improvements to the SXRF analysis

G. J. Flynn; S. R. Sutton

1989-01-01

140

Feasibility Study of X-Ray Fluorescence for Analysis of Welding and Brazing Fumes.  

National Technical Information Service (NTIS)

An X-ray fluorescence technique (XRF) was developed for the analysis of welding and brazing fumes. Welding or brazing fumes were collected on six standard filter cassettes and examined by electron microscopy and X-ray diffraction to assess the particle si...

T. P. Carsey

1980-01-01

141

X-ray optics for scanning fluorescence microscopy and other applications.  

National Technical Information Service (NTIS)

Scanning x-ray fluorescence microscopy is analogous to scanning electron microscopy. Maps of chemical element distribution are produced by scanning with a very small x-ray beam. Goal is to perform such scanning microscopy with resolution in the range of <...

R. W. Ryon W. K. Warburton

1992-01-01

142

(X-ray diffraction experiments with condenser matter)  

SciTech Connect

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

Coppens, P.

1990-01-01

143

Polycapillary optic-enhanced x-ray diffraction and fluorescence for rapid materials analysis  

NASA Astrophysics Data System (ADS)

An energy dispersive x-ray diffraction and fluorescence (EDXRD/XRF) system with no moving parts was developed to monitor in situ the initial stages of thin film growth. The EDXRD/XRF system utilized a low power 25 W microfocus x-ray source and collimating polycapillary optics manufactured by X-Ray Optical Systems (XOS). Metastable semiconductor thin film samples containing phase-separated inclusions of Sn were analyzed for simulation of early deposition stages. The time required to obtain sufficient diffraction data from these thin films was on the order of 60 seconds. Diffraction and fluorescence data were simultaneously obtained making it possible to simultaneously determine the crystal structure and composition of thin films while they are growing. This has the potential for revolutionizing how new materials are developed and commercialized, significantly cutting development and process control costs. An additional XRF system was developed that utilized a low power 20 W microfocus x-ray source and a focusing polycapillary optic. The Sn minimum detectable limit of this system (samples of interest were Ge1-xSnx) was on the order of nanograms using the Sn-L? signal, which corresponds to picograms from a Sn-K? signal. Such low levels are usually only possible with a rotating anode source 103 times more powerful than the low power sealed tube source used in this experiment. An 100nm thin Ge1-xSnx sample made by ion implantation was analyzed with this XRF system. In 300 s, a detectable signal was obtained, indicating the viability of this system for in situ, thin film, composition monitoring and characterization of the first several monolayers of thin film growth.

Schmidt, Joerg; Formica, Sarah P.; Lee, Susanne M.

2005-08-01

144

X-ray experiments on the asteroid surface in a small lander  

NASA Astrophysics Data System (ADS)

A compact X-ray instrument to measure the X-ray fluorescence and diffraction is being devel-oped for the future planetary and asteroid missions, especially for Hayabusa-2. Composition of asteroid is often compared to taxonomic class but it is difficult to find its complete connection between them. Thus it is most important to be measured on site of the surface of asteroid. Remote sensing method is useful to determine major elemental and mineralogical composition for the average or hemispherical scale of the asteroid, especially for the non-carbonaceous S, V, A, E classes. For the carbonaceous C, P, D classes, mineralogy is quite difficult to be deter-mined from its visible to near-infrared spectroscopy. Elemental composition for the majority is in chondritic composition. But detailed analysis allows to classify the chondritic classes in CI, CM, CO, or CV, or to discriminate non-chondritic composition such as ureilite. For car-bonaceous materials, the degree of aqueous alteration is important so that the co-existence of minerals and its more altered components should be measured. X-ray fluorescence method is well established technique for quantitative major elemental com-position in laboratory, and X-ray diffraction method is also well developed technique for crys-tallography of minerals, oxides, and altered materials. Combined method of them is very useful for rock type or meteorite class determination. X-ray CCD based device using a small X-ray tube generator is one of the possible method to achieve its purpose. We have a heritage of CCD technology for X-ray detection (Hayabusa remote X-ray spectrometer) and used the CCD as the 2-dimensional energy photon-counting detector. The method shows almost perfect effi-ciency for XRF, and roughly good performance for XRD to determine most important crystals. But for the small lander experiment, X-ray method should be conducted to measure the rock or sample not prepared in advance for the observation. In that case, our method could be applicable. Such a 10 to 20 cm sized, less than 2 kg class X-ray fluorescence and diffraction analyzer should be needed for future asteroid surface mission.

Okada, Tatsuaki

145

Synchrotron radiation based micro X-ray fluorescence analysis of the calibration samples used in surface sensitive total reflection and grazing emission X-ray fluorescence techniques  

NASA Astrophysics Data System (ADS)

Total reflection X-ray fluorescence (TXRF) and grazing emission X-ray fluorescence (GEXRF) are surface sensitive techniques and can be used for detailed surface studies of different materials, including ultra-low concentration contamination or the lateral and depth distributions of elements. The calibration procedure typically used involves placing a micro-droplet (˜?l) of the standard solution onto a silicon wafer (or quartz backing). After evaporation of the solvent, the residual amount of elements is used as a reference standard. Knowledge of the distribution of residue material on the substrate surface is crucial for precise quantification. In the present work the investigation of the lateral distribution of elements in the multielemental calibrating samples, containing the 23 most commonly studied elements, by using the synchrotron radiation based micro X-ray fluorescence is presented. The goal of this project was the study of a uniformity of the elemental distributions and determination of the residual elements morphology depending on the temperature of the drying process. The X-ray images were compared with optical and SEM images. Paper presents in details the experimental setup, sample preparation procedures, measurements and results. In the analysis of the X-ray images of the sample dried in high temperature the censoring approach was applied improving the quality of statistical analysis. The information on the elements distribution in the calibrating samples can be useful for developing more accurate calibration procedures applied in quantitative analysis of surface sensitive TXRF and GEXRF techniques.

Kubala-Kuku?, A.; Bana?, D.; Pajek, M.; Szlachetko, J.; Jagodzi?ski, P.; Susini, J.; Salomé, M.

2013-12-01

146

Experiment planning for an x-ray material study  

SciTech Connect

An experiment is planned in which up to 3 materials will be subjected to conditions determined by 3 factors: dose, dose rate, and x-ray energy. The 3 materials, new compact material, powdered material, and aged compact material, are referred to simply as 'compact', 'powder' , and 'aged' respectively. Initial consideration of experimental settings for this experiment proposed up to 7 levels of dose, 3 levels of dose rate, and 4 levels of x-ray energy. All combinations of these materials and conditions would yield 3 x 7 x 3 x 4 = 252 possible experiments in the proposed study. However, it is expected that at most 23 experiments can realistically be set-up and monitored. This document describes statistical experiment design methods for obtaining a subset of combinations that efficiently provide the desired information needed from the study.

Moore, Leslie M [Los Alamos National Laboratory; Wendelberger, Joanne R [Los Alamos National Laboratory; Wang, Lily L [Los Alamos National Laboratory

2009-01-01

147

A 30 nm-resolution hard X-ray microscope with X-ray fluorescence mapping capability at BSRF.  

PubMed

A full-field transmission X-ray microscope (TXM) operating continuously from 5 keV to 12 keV with fluorescence mapping capability has been designed and constructed at the Beijing Synchrotron Radiation Facility, a first-generation synchrotron radiation facility operating at 2.5 GeV. Spatial resolution better than 30 nm has been demonstrated using a Siemens star pattern in both absorption mode and Zernike phase-contrast mode. A scanning-probe mode fluorescence mapping capability integrated with the TXM has been shown to provide 50 p.p.m. sensitivity for trace elements with a spatial resolution (limited by probing beam spot size) of 20 µm. The optics design, testing of spatial resolution and fluorescence sensitivity are presented here, including performance measurement results. PMID:23093765

Yuan, Qingxi; Zhang, Kai; Hong, Youli; Huang, Wanxia; Gao, Kun; Wang, Zhili; Zhu, Peiping; Gelb, Jeff; Tkachuk, Andrei; Hornberger, Benjamin; Feser, Michael; Yun, Wenbing; Wu, Ziyu

2012-11-01

148

Laboratory-based micro-X-ray fluorescence setup using a von Hamos crystal spectrometer and a focused beam X-ray tube.  

PubMed

The high-resolution von Hamos bent crystal spectrometer of the University of Fribourg was upgraded with a focused X-ray beam source with the aim of performing micro-sized X-ray fluorescence (XRF) measurements in the laboratory. The focused X-ray beam source integrates a collimating optics mounted on a low-power micro-spot X-ray tube and a focusing polycapillary half-lens placed in front of the sample. The performances of the setup were probed in terms of spatial and energy resolution. In particular, the fluorescence intensity and energy resolution of the von Hamos spectrometer equipped with the novel micro-focused X-ray source and a standard high-power water-cooled X-ray tube were compared. The XRF analysis capability of the new setup was assessed by measuring the dopant distribution within the core of Er-doped SiO2 optical fibers. PMID:24784587

Kayser, Y; B?achucki, W; Dousse, J-Cl; Hoszowska, J; Neff, M; Romano, V

2014-04-01

149

Flow Method and Apparatus for Screening Chemicals Using Micro X-Ray Fluorescence.  

National Technical Information Service (NTIS)

Flow method and apparatus for screening chemicals using micro x-ray fluorescence. The invention includes a method and apparatus for screening a mixture of potential pharmaceutical chemicals for binding to at least one target binder. According to the metho...

B. P. Warner C. A. Mahan C. L. Lewis G. J. Havrilla T. C. Miller

2005-01-01

150

Sample Preparation of Waste Water to Determine Metallic Contaminants by X-Ray Fluorescence Spectroscopy.  

National Technical Information Service (NTIS)

Trace X-ray fluorescence spectroscopy analysis in liquid samples is preceded by sample preparation, which usually consists in the precipitation of the metallic ions and concentration over a thin cellulose filter. The samples preparation of waste water by ...

J. Gonzalez Olivos

1987-01-01

151

Reducing the Size of the Borehole X-Ray Fluorescence Spectrometer (XRFS) Probe: Preliminary Design Study.  

National Technical Information Service (NTIS)

This report describes the preliminary design effort for a borehole X- ray fluorescence spectroscopy (XRFS) instrument for the NASA Mars Subsurface Access Program. The original proposed design was 30 mm in diameter and was based on an existing terrestrial ...

I. A. Carlberg W. C. Kelliher W. T. Elam

2007-01-01

152

Micro-beam X-ray fluorescence and absorption imaging techniques at the IAEA Laboratories  

NASA Astrophysics Data System (ADS)

X-ray tube based, micro-beam X-ray fluorescence scanning spectrometer has been equipped with two energy dispersive X-ray detectors. The two-detector configuration allows for simultaneous collection of X-ray fluorescence (XRF) and transmitted X-ray beam signals with a spatial resolution in the range of 10-50 ?m, depending on the X-ray focussing element in use. The XRF signal is collected with a standard, liquid nitrogen cooled Si(Li) detector. The X-ray beam transmitted through the sample is acquired with a thermoelectrically cooled, silicon drift (SD) detector. The data acquisition is carried out in a fully automatic way under control of the SPECTOR-LOCATOR software. The software controls the scanning procedure and X-ray spectra acquisition during the scan. The energy dispersive X-ray spectra collected at every "pixel" are stored for off-line processing. For selected regions of interest (ROI's), the element maps are constructed and displayed on-line. The spectrometer has been used for mapping elemental distributions and for performing 2D- and 3D-tomograpic imaging of minute objects in X-ray absorption and in X-ray fluorescence mode. A unique feature of the described system is simultaneous utilization of the two detectors, Si(Li) and SD, which adds new options for quantitative analysis and data interpretation. Examples of elemental mapping and 3D tomographic imaging as well as the advanced features of the SPECTOR-LOCATOR measurement control and data acquisition software are presented in this work.

Wegrzynek, Dariusz; Markowicz, A.; Bamford, S.; Chinea-Cano, E.; Bogovac, M.

2005-04-01

153

Critical review of high gain x-ray FEL experiments  

SciTech Connect

There is a renewed interest at the present time to develop x-ray free electron lasers (FELs). The interest is driven by the scientific opportunities with coherent x-rays glimpsed at the third generation light sources. With the recent development in linac technology in producing high-energy, high-brightness electron beams, it is now possible to design intense coherent x-ray source for wavelengths as short as one Angstrom based on the self- amplified spontaneous emission (SASE) principle. Major linac laboratories such as SLAC and DESY are therefore actively pursuing detailed design studies for the x-ray SASE facilities. The x-rays from these facilities will provide a peak brightness more than ten orders of magnitude higher than that of the current synchrotron radiation sources. Short wavelength coherent radiation could also be generated with harmonic generation techniques in linacs or storage rings. However, these schemes are not expected to be effective for 1 {Angstrom} wavelengths. This review will therefore concentrate on the linac based SASE scheme. The critical components of the SASE are: an electron source consisting of an RF photocathode gun with the emittance corrector producing high brightness electron beam; the beam bunching and acceleration; and a long undulator in which the radiation develops from initially incoherent radiation to intense, coherent radiation. We discuss the critical experimental issues in these components highlighting some relevant recent experiments. We also discuss issues related to the SASE experiment which are distinct from the usual free electron lasers. We give a brief survey of the world-wide SASE experiments. We conclude with a summary and outlook.

Kim, Kwang-Je

1996-08-01

154

Development of confocal X-ray fluorescence (XRF) microscopy at the Cornell high energy synchrotron source  

Microsoft Academic Search

A confocal X-ray fluorescence microscope was built at the Cornell High Energy Synchrotron Source (CHESS) to obtain compositional\\u000a depth profiles of historic paintings. The microscope consists of a single-bounce, borosilicate monocapillary optic to focus\\u000a the incident beam onto the painting and a commercial borosilicate polycapillary lens to collect the fluorescent X-rays. The\\u000a resolution of the microscope was measured by scanning

A. R. Woll; J. Mass; C. Bisulca; R. Huang; D. H. Bilderback; S. Gruner; N. Gao

2006-01-01

155

Potential applications of polycapillary optics to polarized beam X-ray fluorescence analysis  

Microsoft Academic Search

The Polarized beam X-ray fluorescence (XRF) technique has potential applications in elemental analysis in materials analysis and in-vivo. In this work, first micro X-ray fluorescence (MXRF) measurements were done using a focusing lens. Polarization can be used to reduce the background, to give a better minimum detection limit. Polarizing the beam, using scattering has a disadvantage of low intensity and

Abrar M. Hussain

2006-01-01

156

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

Microsoft Academic Search

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

Akihiko Kawauchi; Masahiro Ishida; Ikuko Saitoh

1996-01-01

157

Micro-X-ray fluorescence characterization of mixed oxide fuel surrogate feed material  

Microsoft Academic Search

Mixed oxide (MOX) fuel feed material surrogates composed of GaāOā in CeOā were characterized by X-ray fluorescence (XRF) and micro-X-ray fluorescence (MXRF). This work is significant because MOX fuel contains trace levels of GaāOā that could potentially damage the fuel cladding. Because a majority of GaāOā is extracted during MOX fuel feed processing via reduction to volatile and mobile GaāO,

Christopher G. Worley; George J. Havrilla

1998-01-01

158

Microanalysis of solid samples by total-reflection x-ray fluorescence spectrometry  

Microsoft Academic Search

Microgram quantities of different solid powders and smears of alloys were analyzed with total-reflection x-ray fluorescence spectrometry, a special variant of energy-dispersive x-ray fluorescence spectrometry. The samples were analyzed directly without chemical pretreatment. The method works simultaneously for about 20 elements. Quantitative analysis with internal standardization was executed with 10-50 mg of sample mass, but only microgram quantities were necessary

Alex. Von Bohlen; Rudolf. Eller; Reinhold. Klockenkaemper; Guenther. Toelg

1987-01-01

159

X-ray fluorescence spectrometry analysis for minerals with agaron gel for sample preparation  

Microsoft Academic Search

A mineral sample preparation with agaron gel used in X-ray fluorescence analysis was developed. Mineral samples were decomposed with aqua-regia. The sample solution mixed with agaron gel was heated to boiling and then it would become quasi-solid gel under normal temperature. The elements dispersed in gel medium could be detected by X-ray fluorescence spectrometry. The method has both advantages of

Ni Zhang; Tianyi Li; Zuchao Meng; Changna Wang; Ling Ke; Yuhuai Feng

2009-01-01

160

Analysis of mineral water from Brazil using total reflection X-ray fluorescence by synchrotron radiation  

Microsoft Academic Search

The total reflection X-ray fluorescence using synchrotron radiation (SRTXRF) has become a competitive technique for the determination of trace elements in samples that the concentrations are lower than 100 ng ml?1. In this work, thirty-seven mineral waters commonly available in supermarkets of Rio de Janeiro, Brazil, were analyzed by SRTXRF. The measurements were performed at the X-Ray Fluorescence Beamline at

A. C. M. Costa; M. J. Anjos; S. Moreira; R. T. Lopes; E. F. O. de Jesus

2003-01-01

161

Study on the KCl Fluorescent X-rays for the MicroX Imaging Rocket  

NASA Astrophysics Data System (ADS)

The Micro-X High Resolution Microcalorimeter X-ray Imaging Rocket (Micro-X) is an experiment that combines transition-edge-sensors (TES) with a conical imaging mirror, to obtain high-spectral-resolution images of extended X-ray sources. An Fe-55 source will be set on-board to fluoresce a KCl ring to provide calibration lines of 2.62, 2.81, 3.31 and 3.58 keV, these lines will not interfere with the energy band that Micro-X intends to observe, which is from 0.3 to 2.5 keV. An extensive study has been conducted on how the event rate varies when filters of different materials are put in front of the KCl ring. This study was conducted using charge-coupled-devices (CCD), which are commonly used to detect X-ray events with different energies. The study showed that the source plus a single layer of aluminized mylar (thickness 0.01 mm) will provide enough counts of the desired Cl?, Cl?, K?, and K? lines with little to no events in the 0 to 2 keV energy band.

Rodriguez Lopez, Jose A.; Figueroa-Feliciano, Enectali; Leman, Steven W.; Kissel, Steven

2012-03-01

162

Method for detecting binding events using micro-X-ray fluorescence spectrometry  

DOEpatents

Method for detecting binding events using micro-X-ray fluorescence spectrometry. Receptors are exposed to at least one potential binder and arrayed on a substrate support. Each member of the array is exposed to X-ray radiation. The magnitude of a detectable X-ray fluorescence signal for at least one element can be used to determine whether a binding event between a binder and a receptor has occurred, and can provide information related to the extent of binding between the binder and receptor.

Warner, Benjamin P. (Los Alamos, NM) [Los Alamos, NM; Havrilla, George J. (Los Alamos, NM) [Los Alamos, NM; Mann, Grace (Hong Kong, HK) [Hong Kong, HK

2010-12-28

163

Precise non-destructive X-ray fluorescence method for uranium and thorium concentration measurements  

Microsoft Academic Search

A precise non-destructive radioisotope X-ray fluorescence method for uranium and thorium concentration measurements was developed.\\u000a A beta-emitting90Sr?90Y source was used for excitation of characteristic X-ray lines. It is proved that the beta-excited X-ray fluorescence method\\u000a (in spite of the significant bremsstrahlung intensity) has essential advantages for analysis of high concentrations of U and\\u000a Th, characteristic for nuclear power cycle materials,

T. N. Dragnev; J. Karamanova; B. Damianov

1979-01-01

164

New approach to breast tumor detection based on fluorescence x-ray analysis  

PubMed Central

A new technical approach to breast-tumor detection is proposed. The technique is based on fluorescence x-ray analysis, and can identify a miniature malignant tumor within the breast. The primary beam intensity needed in fluorescence x-ray analysis is on a lower order of magnitude than that used in mammography. Thus, the newly-proposed technique would enable detection of a still tiny breast cancer while dramatically lowering the radiation dose. Field-emission x-ray sources might be a key for translating this concept into a medical technique.

Hayashi, Yasuhiko; Okuyama, Fumio

2010-01-01

165

X-ray detectors of the CAST experiment  

NASA Astrophysics Data System (ADS)

CERN Axion Solar Telescope (CAST) is an experiment probing hypothetical particles: the axions, created in the solar core. Inside the transverse magnetic field of the CAST magnet, axions can be converted into x-rays, and be detected by four x-ray detectors at CAST. The expected x-ray signal in CAST is in 1–10 keV range, intensity depending strongly on the coupling constant of axion-photon conversion ga?, which is expected to be low. This requires CAST to have detectors with very low background levels. The CAST Experiment makes use of three Micromesh Gaseous Structure (micromegas) detectors, which are gaseous detectors, derived from ideas of Multiwire Proportional Chambers (MWPC). CAST Micromegas detectors show perfect stability, good spatial and energy resolution. The intense study on Micromegas has enabled CAST to understand the nature of its background level, and improve it by a factor of 102 over ten years. New detector design, new readout system, better cosmic veto and addition of x-ray telescope will further improve the background in the next data taking of the experiment. The Charge-Coupled Device (CCD) of CAST is a pn-CCD detector with 200 × 64 pixels. The CAST CCD is coupled to an X-ray telescope, focusing all the parallel x-rays into a 9 mm diameter spot. The CCD will be replaced by the InGrid detector, a special manufactured micromegas detector. It is able to detect single electrons, and the low energy capabilities will open new frontiers on search of axions and other exotic particles. Another option is the Silicon Drift Detector (SDD), which is being tested in 2013, and has an energy threshold as low as 250 eV. The CAST experiment is the pioneering helioscope that excludes an important part of axion mass-coupling constant parameter space, and expects to exclude more in the following years. To succeed CAST, a new experiment, the International AXion Observatory (IAXO) is being designed and optimised, comprising the construction of a magnet specially built for axion search as well as new detectors that will enable to improve the actual limits by 1–1.5 orders of magnitude.

Yildiz, S. C.

2014-03-01

166

ISS Ammonia Leak Detection Through X-Ray Fluorescence  

NASA Technical Reports Server (NTRS)

Ammonia leaks are a significant concern for the International Space Station (ISS). The ISS has external transport lines that direct liquid ammonia to radiator panels where the ammonia is cooled and then brought back to thermal control units. These transport lines and radiator panels are subject to stress from micrometeorites and temperature variations, and have developed small leaks. The ISS can accommodate these leaks at their present rate, but if the rate increased by a factor of ten, it could potentially deplete the ammonia supply and impact the proper functioning of the ISS thermal control system, causing a serious safety risk. A proposed ISS astrophysics instrument, the Lobster X-Ray Monitor, can be used to detect and localize ISS ammonia leaks. Based on the optical design of the eye of its namesake crustacean, the Lobster detector gives simultaneously large field of view and good position resolution. The leak detection principle is that the nitrogen in the leaking ammonia will be ionized by X-rays from the Sun, and then emit its own characteristic Xray signal. The Lobster instrument, nominally facing zenith for its astrophysics observations, can be periodically pointed towards the ISS radiator panels and some sections of the transport lines to detect and localize the characteristic X-rays from the ammonia leaks. Another possibility is to use the ISS robot arm to grab the Lobster instrument and scan it across the transport lines and radiator panels. In this case the leak detection can be made more sensitive by including a focused 100-microampere electron beam to stimulate X-ray emission from the leaking nitrogen. Laboratory studies have shown that either approach can be used to locate ammonia leaks at the level of 0.1 kg/day, a threshold rate of concern for the ISS. The Lobster instrument uses two main components: (1) a microchannel plate optic (also known as a Lobster optic) that focuses the X-rays and directs them to the focal plane, and (2) a CCD (charge coupled device) focal plane detector that reads out the position and energy of the X-rays, allowing a determination of the leak location. The effective area of the detection system is approximately 2 cm(exp2) at 1 keV. The Lobster astrophysics instrument, designed for monitoring the sky for Xray transients, gives high sensitivity along with large field of view (30×30deg) and good spatial resolution (1 arc min). This offers a significant benefit for detecting ISS ammonia leaks, since the goal is to localize small leaks as efficiently as possible.

Camp, Jordan; Barthelmy, Scott; Skinner, Gerry

2013-01-01

167

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

Microsoft Academic Search

Total reflection X-ray fluorescence (TXRF) was used to determine sulfur, chlorine, potassium, and calcium in atmospheric aerosol samples. Aerosols collected in a size fractionation cascade impact collector were dissolved in water, and the solution was placed on a quartz X-ray reflector plate. Cobalt was used as the internal standard added to the solution after dissolution of the aerosol. Detection units

Leland

1989-01-01

168

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

Microsoft Academic Search

This work comprises the use of energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) techniques for the study of the composition of twentieth century traditional Japanese color sticks. By using the combination of analytical techniques it was possible to obtain information on inorganic and organic pigments, binders and fillers present in the sticks. The colorant

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

2010-01-01

169

Project Title: Radiochemical Analysis by High Sensitivity Dual-Optic Micro X-ray Fluorescence  

SciTech Connect

A novel dual-optic micro X-ray fluorescence instrument will be developed to do radiochemical analysis of high-level radioactive wastes at DOE sites such as Savannah River Site and Hanford. This concept incorporates new X-ray optical elements such as monolithic polycapillaries, which focus X-rays. The polycapillary optic can be used to focus X-rays emitted by the X-ray tube thereby increasing the X-ray flux on the sample over 1000 times. The polycapillary optic will also be used to collect the X-rays from the excitation site. This will effectively screen the radiation background from the radioactive species in the specimen. This dual-optic approach significantly reduces the background and increases the analyte signal thereby increasing the sensitivity of the analysis. This dual-capillary design is essentially a confocal (having the same foci) design, i.e. the detected X-rays are only emitted from the overlap of the two focal spots. This increases spatial resolution and reduce s background. The integration of the X-ray optics increases the signal-to-noise and thereby increases the sensitivity of the analysis for low-level analytes. This work will address a key need for radiochemical analysis of high-level waste using a non-destructive, multi-element, and rapid method in a radiation environment. There is significant potential that this instrumentation could be capable of on-line analysis for process waste stream characterization at DOE sites.

Havrilla, George J.; Gao, Ning

2003-06-01

170

Radiochemical Analysis by High Sensitivity Dual-Optic Micro X-ray Fluorescence  

SciTech Connect

A novel dual-optic micro X-ray fluorescence instrument will be developed to do radiochemical analysis of high-level radioactive wastes at DOE sites such as Savannah River Site and Hanford. This concept incorporates new X-ray optical elements such as monolithic polycapillaries, which focus X-rays. The polycapillary optic can be used to focus X-rays emitted by the X-ray tube thereby increasing the X-ray flux on the sample over 1000 times. The polycapillary optic will also be used to collect the X-rays from the excitation site. This will effectively screen the radiation background from the radioactive species in the specimen. This dual-optic approach significantly reduces the background and increases the analyte signal thereby increasing the sensitivity of the analysis. This dual-capillary design is essentially a confocal (having the same foci) design, i.e. the detected X-rays are only emitted from the overlap of the two focal spots. This increases spatial resolution and reduces background. The integration of the X-ray optics increases the signal-to-noise and thereby increases the sensitivity of the analysis for low-level analytes. This work will address a key need for radiochemical analysis of high-level waste using a non-destructive, multi-element, and rapid method in a radiation environment. There is significant potential that this instrumentation could be capable of on-line analysis for process waste stream characterization at DOE sites.

Havrilla, George J.; Gao, Ning

2004-06-01

171

Determination of L X-ray fluorescence parameters for Ho, Lu, W, Hg and Bi.  

PubMed

In this work, L X-ray fluorescence cross sections, L sub-shell fluorescence yields and level widths and radiative vacancy transfer probabilities of L sub-shells to Mi, Ni and Oi sub-shells were measured for the elements Ho, Lu, W, Hg and Bi. Energy dispersive X-ray fluorescence (EDXRF) technique was used to measure L X-ray photons. To obtain related parameters, we used 59.54keV gamma photons of (241)Am radioactive point source. Emitted L X-ray photons from targets were collected by means of a Si(Li) detector with resolution of 180eV at 5.9keV. The present results are generally in a good agreement with theoretical calculations and the other results obtained in the literature, within their range considering experimental uncertainty. PMID:24631748

Turhan, M F; Durak, R; Akman, F

2014-07-01

172

Development and applications of an epifluorescence module for synchrotron x-ray fluorescence microprobe imaging  

SciTech Connect

Synchrotron x-ray fluorescence (XRF) microprobe is a valuable analysis tool for imaging trace element composition in situ at a resolution of a few microns. Frequently, epifluorescence microscopy is beneficial for identifying the region of interest. To date, combining epifluorescence microscopy with x-ray microprobe has involved analyses with two different microscopes. We report the development of an epifluorescence module that is integrated into a synchrotron XRF microprobe beamline, such that visible fluorescence from a sample can be viewed while collecting x-ray microprobe images simultaneously. This unique combination has been used to identify metal accumulation in Alzheimer's disease plaques and the mineral distribution in geological samples. The flexibility of this accessory permits its use on almost any synchrotron x-ray fluorescence microprobe beamline and applications in many fields of science can benefit from this technology.

Miller, Lisa M.; Smith, Randy J.; Ruppel, Meghan E.; Ott, Cassandra H.; Lanzirotti, Antonio [National Synchrotron Light Source, Building 725D, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Department of Material Science and Engineering, Stony Brook University, Stony Brook, New York 11794-2200 (United States); Consortium for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637 (United States)

2005-06-15

173

Description of the dependence of intensity of x-ray fluorescence on the particle size of powder samples and pulp during x-ray fluorescent analysis  

Microsoft Academic Search

The dependence of intensity of x-ray fluorescence on particle size for powdered and pulplike media is described using a general\\u000a analytical expression. The expression is obtained for a model of a powder medium consisting of particles of various sizes\\u000a distributed randomly in the sample bulk. This expression involves expressions for the fluorescence intensity for homogeneous\\u000a and pulplike media as limiting

A. L. Finkel’shtein; T. N. Gunicheva

2008-01-01

174

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

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

175

Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE)  

NASA Technical Reports Server (NTRS)

This report summarizes the activities sponsored by the Office of Naval Research for the Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE). The MAXIE instrument was developed as a joint activity of Lockheed, The Aerospace Corporation, and the University of Bergen, Norway. Lockheed was responsible for the overall management of the program, interfacing with the appropriate government agencies, the overall electrical and mechanical design, flight software, environmental testing, spacecraft integration activities, on orbit checkout, and data processing activities. The Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE), the ONR 401 experiment, is the first in a new class of satellite-borne remote sensing instruments. The primary innovation is the ability to obtain rapid, sequential, images with high sensitivity of the earth's X ray aurora from a low altitude polar orbiting satellite. These images can be used to identify dynamic temporal variations in the three-dimensional (energy and position) distribution of electron precipitation into the atmosphere. MAXIE was launched on the TIROS NOAA-13 satellite on 9 August 1993. The experiment performed well during its turn-on sequence; however, the spacecraft bus failed on 21 August 1993. New spacebased technologies successfully used in MAXIE were mixed-mode ASIC microcircuits, a zero torque scanning system with associated viscoelastic damping, a paraffin stow release mechanism, a parallel integrating PHA processor, a low noise Si(Li) sensor telescope, and an advanced thermal cooling system. MAXIE's on orbit operation, control of penetrating particle backgrounds, and scientific data indicated good overall performance.

Imhof, W. L.; Voss, H. D.; Mobilia, J.; Datlowe, D. W.; Chinn, V. L.; Hilsenrath, M.; Vondrak, R. R.

1996-01-01

176

The cosmic X-ray experiment aboard HEAO-1  

NASA Technical Reports Server (NTRS)

The HEAO-1 A-2 experiment, designed to study the large scale structure of the galaxy and the universe at X-ray energies is described. The instrument consists of six gas proportional counters of three types nominally covering the energy ranges of 0.15-3 keV, 1.2-20 keV, and 2.5-60 keV. The two low energy detectors have about 400 sq cm open area each while the four others have about 800 sq cm each. Dual field of view collimators allow the unambiguous determination of instrument internal background and diffuse X-ray brightness. Instrument characteristics and early performance are discussed.

Rothschild, R. E.; Bolt, E.; Holt, S.; Serlemitsos, P. J.; Garmire, G.; Agrawal, P.; Reigler, G.; Bowyer, C. S.; Lampton, M.

1978-01-01

177

A bent silicon crystal in the Laue geometry to resolve actinide x-ray fluorescence for x-ray absorption spectroscopy  

Microsoft Academic Search

A highly strained, curved silicon crystal in the Laue geometry has been used as a large area x-ray fluorescence analyzer for x-ray absorption spectroscopy. The analyzer is able to resolve the L? fluorescence lines for neighboring actinide elements. A large gain in the signal-to-background ratio has been achieved for low levels of Mo, Np, and Pu in a UO2 matrix.

A J Kropf; J A Fortner; R J Finch; J C Cunnane; C Karanfil

2005-01-01

178

Characterization of a confocal three-dimensional micro X-ray fluorescence facility based on polycapillary X-ray optics and Kirkpatrick–Baez mirrors  

Microsoft Academic Search

A new confocal three-dimensional micro X-ray fluorescence (3D micro-XRF) facility based on polycapillary X-ray optics in the detection channel and Kirkpatrick–Baez (KB) mirrors in the excitation channel is designed. The lateral resolution (lx, ly) of this confocal three-dimensional micro-X-ray fluorescence facility is 76.3(lx) and 53.4(ly) µm respectively, and its depth resolution dz is 77.1 ?m at ?=90°. A plant sample (twig

Tianxi Sun; Xunliang Ding; Zhiguo Liu; Guanghua Zhu; Yude Li; Xiangjun Wei; Dongliang Chen; Qing Xu; Quanru Liu; Yuying Huang; Xiaoyan Lin; Hongbo Sun

2008-01-01

179

OSO-8 soft X-ray wheel experiment: Data analysis  

NASA Technical Reports Server (NTRS)

The soft X-ray experiment hardware and its operation are described. The device included six X-ray proportional counters, two of which, numbers 1 and 4, were pressurized with on-board methane gas supplies. Number 4 developed an excessive leak rate early in the mission and was turned off on 1975 day number 282 except for brief (typically 2-hour) periods up to day 585 after which it as left off. Counter 1 worked satisfactorily until 1975 day number 1095 (January 1, 1978) at which time the on-board methane supply was depleted. The other four counters were sealed and all except number 3 worked satisfactorily throughout the mission which terminated with permanent satellie shut-down on day 1369. This was the first large area thin-window, gas-flow X-ray detector to be flown in orbit. The background problems were severe and consumed a very large portion of the data analysis effort. These background problems were associated with the Earth's trapped electron belts.

Kraushaar, W. L.

1982-01-01

180

An X-ray fluorescence spectrometer and its applications in materials studies  

NASA Technical Reports Server (NTRS)

An X-ray fluorescence system based on a Co(57) gamma-ray source has been developed. The system was used to calculate the atomic percentages of iron implanted in titanium targets. Measured intensities of Fe (k-alpha + k-beta) and Ti (k-alpha + k-beta) X-rays from the Fe-Ti targets are in good agreement with the calculated values based on photoelectric cross sections of Ti and Fe for the Co(57) gamma rays.

Singh, J. J.; Han, K. S.

1977-01-01

181

Synchrotron-based X-ray fluorescence, imaging and elemental mapping from biological samples  

Microsoft Academic Search

.  The present study utilized the new hard X-ray microspectroscopy beamline facility, X27A, available at NSLS, BNL, USA, for\\u000a elemental mapping. This facility provided the primary beam in a small spot of the order of ?10 ?m, for focussing. With this spatial resolution and high flux throughput, the synchrotron-based X-ray fluorescent intensities\\u000a for Mn, Fe, Zn, Cr, Ti and Cu were measured using

D. V. Rao; M. Swapna; R. Cesareo; A. Brunetti; T. Akatsuka; T. Yuasa; T. Takeda; G E GIGANTE

2011-01-01

182

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

Microsoft Academic Search

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

Yoshiki Mino

2006-01-01

183

X-Ray Fluorescence Spectrometry of Itokawa and its implication to meteorite connection  

Microsoft Academic Search

The CCD-based X-ray spectrometer XRS onboard Hayabusa has performed X-ray fluorescence spectrometry of the S- IV class near-Earth asteroid 25143 Itokawa to determine major elemental composition of the asteroid during the rendezvous phase We present here the results of the XRS observation indicating that the surface of Itokawa has chondritic composition and that LL- or L-chondrites are most likely but

T. Okada; K. Shirai; Y. Yamamoto; T. Arai; K. Ogawa; K. Hosono; To. Inoue; Ta. Inoue; Y. Maruyama; M. Kato

2006-01-01

184

X-ray absorption spectroscopy: A fluorescence detection system based on a plastic scintillator  

Microsoft Academic Search

A fluorescence detection system based on a plastic scintillator is presented that can be used for both X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Its counting rate is limited by the pulsation frequency of the synchrotron radiation (3.16×106 counts s-1), and can be theoretically extended to roughly 5×107 counts s-1 if used on a multibunch

G. Tourillon; D. Guay; M. Lemonnier; F. Bartol; M. Badeyan

1990-01-01

185

Surface elemental analysis in ambient atmosphere using electron-induced x-ray fluorescence  

Microsoft Academic Search

The progress in the development of the atmospheric electron x-ray spectrometer (AEXS) is described. The AEXS is a surface analysis tool based on excitation of characteristic x-ray fluorescence (XRF) spectra from samples in ambient atmospheres using a focused electron beam. Operation in ambient atmospheres with moderate-to-high spatial resolution in comparison to similar instruments is obtained through the use of a

Eduardo Urgiles; Risaku Toda; Jaroslava Z. Wilcox

2006-01-01

186

NBSGSC - a FORTRAN program for quantitative x-ray fluorescence analysis. Technical note (final)  

Microsoft Academic Search

A FORTRAN program (NBSGSC) was developed for performing quantitative analysis of bulk specimens by x-ray fluorescence spectrometry. This program corrects for x-ray absorption\\/enhancement phenomena using the comprehensive alpha coefficient algorithm proposed by Lachance (COLA). NBSGSC is a revision of the program ALPHA and CARECAL originally developed by R.M. Rousseau of the Geological Survey of Canada. Part one of the program

G. Y. Tao; P. A. Pella; R. M. Rousseau

1985-01-01

187

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

Microsoft Academic Search

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

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

1978-01-01

188

Synchrotron radiation induced ?-X-ray fluorescence spectroscopy on municipal solid waste fly ashes  

Microsoft Academic Search

The high brightness of synchrotron radiation sources of the 3rd generation and the development of focusing optical elements for X-rays make it possible to create beams of micrometer size with high intensity. These beams can be used to reveal spatially resolved information about structural and chemical properties of particles. Here, the possibility of using synchrotron radiation micro-X-ray fluorescence (?-SRXRF) for

Maria Caterina Camerani; Andrea Somogyi; Mikael Drakopoulos; Britt-Marie Steenari

2001-01-01

189

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

Microsoft Academic Search

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

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

1998-01-01

190

Development of a new total reflection X?ray fluorescence instrument using polycapillary X?ray lens  

Microsoft Academic Search

A new TXRF instrument combined with micro?XRF analytical technique was proposed. An X?ray micro?beam was obtained by using a polycapillary X?ray lens. The evaluated diameter of the X?ray beam at the focal distance was 35 ?m. In order to satisfy the total reflection condition of the present instrument, we attempted to cut the X?ray micro?beam above the critical angle of the

K. Nakano; K. Tanaka; X. Ding; K. Tsuji

2006-01-01

191

Design and characterization of a pulsed x-ray source for fluorescent lifetime measurements  

SciTech Connect

To search for new, fast, inorganic scintillators, the author and his colleagues have developed a bench-top pulsed x-ray source for determining fluorescent lifetimes and wavelengths of compounds in crystal or powdered form. This source uses a light-excited x-ray tube which produces x-rays when light from a laser diode strikes its photocathode. The x-ray tube has a tungsten anode, a beryllium exit window, a 30 kV maximum tube bias, and a 50 HA maximum average cathode current. The laser produces 3 {times} 10{sup 7} photons at 650 nm per {approximately}100 ps pulse, with up to 10{sup 7} pulses/sec. The time spread for the laser diode, x-ray tube, and a microchannel plate photomultiplier tube is less than 120 ps fwhm. The mean x-ray photon energy, at tube biases of 20, 25, and 30 kV, is 9.4, 10.3, and 11.1 keV, respectively. They measured 140, 230, and 330 x-ray photons per laser diode pulse per steradian at tube biases of 20, 25, and 30 kV, respectively. Background x-rays due to dark current occur at a rate of 1 {times} 10{sup 6} and 3 {times} 10{sup 6} photons/sec/steradian at tube biases of 25 and 30 kV, respectively. Data characterizing the x-ray output with an aluminum filter in the x-ray beam are also presented.

Blankespoor, S.C. [Univ. of California, Berkeley, CA (United States). Dept. of Electrical Engineering and Computer Science]|[Lawrence Berkeley Lab., CA (United States)

1993-12-01

192

Project Title: Radiochemical Analysis by High Sensitivity Dual-Optic Micro X-ray Fluorescence  

SciTech Connect

A novel dual-optic micro X-ray fluorescence instrument will be developed to do radiochemical analysis of high-level radioactive wastes at DOE sites such as Savannah River Site and Hanford. This concept incorporates new X-ray optical elements such as monolithic polycapillaries and double bent crystals, which focus X-rays. The polycapillary optic can be used to focus X-rays emitted by the X-ray tube thereby increasing the X-ray flux on the sample over 1000 times. Polycapillaries will also be used to collect the X-rays from the excitation site and screen the radiation background from the radioactive species in the specimen. This dual-optic approach significantly reduces the background and increases the analyte signal thereby increasing the sensitivity of the analysis. A doubly bent crystal used as the focusing optic produces focused monochromatic X-ray excitation, which eliminates the bremsstrahlung background from the X-ray source. The coupling of the doubly bent crystal for monochromatic excitation with a polycapillary for signal collection can effectively eliminate the noise background and radiation background from the specimen. The integration of these X-ray optics increases the signal-to-noise and thereby increases the sensitivity of the analysis for low-level analytes. This work will address a key need for radiochemical analysis of high-level waste using a non-destructive, multi-element, and rapid method in a radiation environment. There is significant potential that this instrumentation could be capable of on-line analysis for process waste stream characterization at DOE sites.

Havrilla, George J.; Gao, Ning

2002-06-01

193

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

194

Modeling current and proposed COMET x-ray laser experiments  

NASA Astrophysics Data System (ADS)

We model recent experiments done using the COMET laser at Lawrence Livermore National Laboratory to illuminate slab targets of Pd up to 1.25 cm long with a two joule, 600 ps prepulse followed 700 psec later by a six joule, six psec drive pulse. The experiments measure the two-dimensional near-field and far-field laser patterns for the 14.7 nm Ni-like Pd x-ray laser line. The experiments are modeled using the LASNEX code to calculate the hydrodynamic evolution of the plasma and provide the temperatures and densities to the CRETIN code, which then does the kinetics calculations to determine the gain. Using a ray tracing code to simulate the near and far-field output the simulations are then compared with experiments. In addition we model recent experiments that used a streak camera to measure the time duration of the Pd X-ray laser when pumped with a constant energy short pulse with different time durations that ranged from 0.5 to 27 ps.

Nilsen, Joseph; Dunn, James; Smith, Raymond F.

2003-12-01

195

Soft x-ray laser experiments at Novette Laser Facility  

SciTech Connect

We discuss the results of and future plans for experiments to study the possibility of producing an x-ray laser. The schemes we have investigated are all pumped by the Novette Laser, operated at short pulse (tau/sub L/ approx. 100 psec) and an incident wavelength of lambda /sub L/ approx. 0.53 ..mu..m. We have studied the possibility of lasing at 53.6, 68.0 to 72.0, 119.0, and 153.0 eV, using the inversion methods of resonant photo-excitation, collisional excitation, and three-body recombination.

Matthews, D.; Hagelstein, P.; Rosen, M.; Kauffman, R.; Lee, R.; Wang, C.; Medecki, H.; Campbell, M.; Ceglio, N.; Leipelt, G.

1984-03-05

196

X-ray fluorescence spectroscopy from ions at charged vapor/water interfaces  

SciTech Connect

X-ray fluorescence spectra from monovalent ions (Cs{sup +}) that accumulate from dilute solutions to form an ion-rich layer near a charged Langmuir monolayer are presented. For the salt solution without the monolayer, the fluorescence signals below the critical angle are significantly lower than the detection sensitivity and only above the critical angle signals from the bulk are observed. In the presence of a monolayer that provides surface charges, strong fluorescence signals below the critical angle are observed. Ion density accumulated at the interface are determined from the fluorescence. The fluorescent spectra collected as a function of incident x-ray energy near the L{sub III} edge yield the extended absorption spectra from the ions, and are compared to recent independent results. The fluorescence data from divalent Ba{sup 2+} with and without monolayer are also presented.

Bu Wei; Vaknin, David [Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

2009-04-15

197

Calculating the X-Ray Fluorescence from the Planet Mercury Due to High-Energy Electrons  

NASA Technical Reports Server (NTRS)

The least-studied terrestrial planet is Mercury due to its proximity to the Sun, which makes telescopic observations and spacecraft encounters difficult. Our lack of knowledge about Mercury should change in the near future due to the recent launching of MESSENGER, a Mercury orbiter. Another mission (BepiColombo) is currently being planned. The x-ray spectrometer on MESSENGER (and planned for BepiColombo) can characterize the elemental composition of a planetary surface by measuring emitted fluorescent x-rays. If electrons are ejected from an atom s inner shell by interaction with energetic particles such as photons, electrons, or ions, electrons from an outer shell can transfer to the inner shell. Characteristic x-rays are then emitted with energies that are the difference between the binding energy of the ion in its excited state and that of the ion in its ground state. Because each element has a unique set of energy levels, each element emits x-rays at a unique set of energies. Electrons and ions usually do not have the needed flux at high energies to cause significant x-ray fluorescence on most planetary bodies. This is not the case for Mercury where high-energy particles were detected during the Mariner 10 flybys. Mercury has an intrinsic magnetic field that deflects the solar wind, resulting in a bow shock in the solar wind and a magnetospheric cavity. Electrons and ions accelerated in the magnetosphere tend to follow its magnetic field lines and can impact the surface on Mercury s dark side Modeling has been done to determine if x-ray fluorescence resulting from the impact of high-energy electrons accelerated in Mercury's magnetosphere can be detected by MESSENGER. Our goal is to understand how much bulk chemical information can be obtained from x-ray fluorescence measurements on the dark side of Mercury.

Burbine, T. H.; Trombka, J. I.; Bergstrom, P. M., Jr.; Christon, S. P.

2005-01-01

198

Medical imaging by fluorescent x-ray CT: its preliminary clinical evaluation  

NASA Astrophysics Data System (ADS)

Fluorescent x-ray CT (FXCT) with synchrotron radiation (SR) is being developed to detect the very low concentration of specific elements. The endogenous iodine of the human thyroid and the non-radioactive iodine labeled BMIPP in myocardium were imaged by FXCT. FXCT system consists of a silicon (111) double crystal monochromator, an x-ray slit, a scanning table for object positioning, a fluorescent x-ray detector, and a transmission x-ray detector. Monochromatic x-ray with 37 keV energy was collimated into a pencil beam (from 1 mm to 0.025 mm). FXCT clearly imaged endogenous iodine of thyroid and iodine labeled BMIPP in myocardium, whereas transmission x-ray CT could not demonstrate iodine. The distribution of iodine was heterogeneous within thyroid cancer, and its concentration was lower than that of normal thyroid. Distribution of BMIPP in normal rat myocardium was almost homogeneous; however, reduced uptake was slightly shown in ischemic region. FXCT is a highly sensitive imaging modality to detect very low concentration of specific element and will be applied to reveal endogenous iodine distribution in thyroid and to use tracer study with various kinds of labeled material.

Takeda, Tohoru; Zeniya, Tsutomu; Wu, Jin; Yu, Quanwen; Lwin, Thet T.; Tsuchiya, Yoshinori; Rao, Donepudi V.; Yuasa, Tetsuya; Yashiro, Toru; Dilmanian, F. Avraham; Itai, Yuji; Akatsuka, Takao

2002-01-01

199

Measurement of soft X-ray absorption spectra with a fluorescent ion chamber detector  

NASA Astrophysics Data System (ADS)

The problem of absorption of soft X-rays by thick Be windows in hard X-ray beam lines is well known. Although the signal at 2.4 keV was reduced by ˜ 10 3 we have routinely measured the absorption spectra of S (2472 eV) and elements at higher energies including Cl, Ar and K. These spectra were obtained on hard X-ray beam lines at Stanford Synchrotron Radiation Laboratory (SSRL) with Si(111) monochromator crystals and a fluorescent ion chamber detector [1]. Higher energy harmonics were minimized by detuning and the end station was enclosed in a helium bag to prevent absorption by air. Although the diminished X-ray flux and decreasing fluorescent yield were serious negative factors at these low X-ray energies the spectra from thick samples were of excellent quality with sufficient sensitivity to characterize 1% S in coal. Representative spectra are shown comparing data from focused and unfocused beam lines and with S data from JUMBO [2]. Comparison of Ar and KCl data to excellent data found in the older literature [3-5] allow a confirmation of the resolution function (energy bandpass) of the monochromator. A simple new beam line is suggested which would allow a substantial increase in low energy X-ray flux (measurements down to Al and Si) with the sample and detector in a He atmosphere.

Lytle, F. W.; Greegor, R. B.; Sandstrom, D. R.; Marques, E. C.; Wong, Joe; Spiro, C. L.; Huffman, G. P.; Huggins, F. E.

1984-10-01

200

Hyper-filter-fluorescer spectrometer for x rays above 120 keV  

Microsoft Academic Search

We present a new method of utilizing a filter--fluorescer system for measuring high fluence x-rays above 120 keV, where there are no practical absorption edges available for conventional filter--fluorescer techniques. The absorption edge (E\\/sub p\\/ keV) of the prefilter is chosen to be less than that of the fluorescer (E\\/sub f\\/ keV), i.e., E\\/sub p\\/

C. L. Wang

1981-01-01

201

Hyper-filter–fluorescer spectrometer for x rays above 120 keV  

Microsoft Academic Search

We present a new method of utilizing a filter–fluorescer system for measuring high fluence x-rays above 120 keV, where there are no practical absorption edges available for conventional filter–fluorescer techniques. The absorption edge (Ep keV) of the prefilter is chosen to be less than that of the fluorescer (Ef keV), i.e., Ep

C. L. Wang

1981-01-01

202

Modeling of x-ray fluorescence using MCNPX and Geant4  

SciTech Connect

X-Ray Fluorescence (XRF) is one of thirteen non-destructive assay techniques being researched for the purpose of quantifying the Pu mass in used fuel assemblies. The modeling portion of this research will be conducted with the MCNPX transport code. The research presented here was undertaken to test the capability of MCNPX so that it can be used to benchmark measurements made at the ORNL and to give confidence in the application of MCNPX as a predictive tool of the expected capability of XRF in the context of used fuel assemblies. The main focus of this paper is a code-to-code comparison between MCNPX and Geant4 code. Since XRF in used fuel is driven by photon emission and beta decay of fission fragments, both terms were independently researched. Simple cases and used fuel cases were modeled for both source terms. In order to prepare for benchmarking to experiments, it was necessary to determine the relative significance of the various fission fragments for producing X-rays.

Rajasingam, Akshayan [Los Alamos National Laboratory; Hoover, Andrew S [Los Alamos National Laboratory; Fensin, Michael L [Los Alamos National Laboratory; Tobin, Stephen J [Los Alamos National Laboratory

2009-01-01

203

Total Reflection X-ray Fluorescence attachment module modified for analysis in vacuum  

NASA Astrophysics Data System (ADS)

Based on the design of the low cost Total Reflection X-Ray Fluorescence attachment module available since 1986 from Atominstitut (WOBRAUSCHEK-module) which can be attached to existing X-ray equipment, a new version was developed which allows the analysis of samples in vacuum. This design was in particular possible as the Peltier cooled light weight Silicon Drift Detector is following all adjustment procedures for total reflection as angle rotation and linear motion. The detector is mounted through a vacuum feed and O-ring tightening to the small vacuum chamber. The standard 30 mm round quartz, Si-wafer or Plexiglas reflectors are used to carry the samples. The reflectors are placed on the reference plane with the dried sample down looking facing in about 0.5 mm distance the up looking detector window. The reflectors are resting on 3 steel balls defining precisely the reference plane for the adjustment procedure. As the rotation axis of the module is in the plane of the reflector surface, angle dependent experiments can be made to distinguish between film and particulate type contamination of samples. Operating with a Mo anode at 50 kV and 40 mA with a closely attached multilayer monochromator and using a 10 mm 2 KETEK silicon drift detector with 8 ?m Be window, a sensitivity of 70 cps/ng for Rb was measured and detection limits of 2 pg were obtained.

Wobrauschek, P.; Streli, C.; Kregsamer, P.; Meirer, F.; Jokubonis, C.; Markowicz, A.; Wegrzynek, D.; Chinea-Cano, E.

2008-12-01

204

Simultaneous X-ray fluorescence and ptychographic microscopy of Cyclotella meneghiniana.  

PubMed

Scanning X-ray fluorescence microscopy (XFM) is a particularly useful method for studying the spatial distribution of trace metals in biological samples. Here we demonstrate the utility of combining coherent diffractive imaging (CDI) with XFM for imaging biological samples to simultaneously produce high-resolution and high-contrast transmission images and quantitative elemental maps. The reconstructed transmission function yields morphological details which contextualise the elemental maps. We report enhancement of the spatial resolution in both the transmission and fluorescence images beyond that of the X-ray optics. The freshwater diatom Cyclotella meneghiniana was imaged to demonstrate the benefits of combining these techniques that have complementary contrast mechanisms. PMID:23038378

Vine, D J; Pelliccia, D; Holzner, C; Baines, S B; Berry, A; McNulty, I; Vogt, S; Peele, A G; Nugent, K A

2012-07-30

205

X-RAY FLUORESCENCE ANALYSIS OF HANFORD LOW ACTIVITY WASTE SIMULANTS METHOD DEVELOPMENT  

SciTech Connect

The x-ray fluorescence laboratory (XRF) in the Analytical Development Directorate (ADD) of the Savannah River National Laboratory (SRNL) was requested to develop an x-ray fluorescence spectrometry method for elemental characterization of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) pretreated low activity waste (LAW) stream to the LAW Vitrification Plant. The WTP is evaluating the potential for using XRF as a rapid turnaround technique to support LAW product compliance and glass former batching. The overall objective of this task was to develop an XRF analytical method that provides rapid turnaround time (<8 hours), while providing sufficient accuracy and precision to determine variations in waste.

Jurgensen, A; David Missimer, D; Ronny Rutherford, R

2007-08-08

206

The MicroAnalysis Toolkit: X-ray Fluorescence Image Processing Software  

SciTech Connect

The MicroAnalysis Toolkit is an analysis suite designed for the processing of x-ray fluorescence microprobe data. The program contains a wide variety of analysis tools, including image maps, correlation plots, simple image math, image filtering, multiple energy image fitting, semi-quantitative elemental analysis, x-ray fluorescence spectrum analysis, principle component analysis, and tomographic reconstructions. To be as widely useful as possible, data formats from many synchrotron sources can be read by the program with more formats available by request. An overview of the most common features will be presented.

Webb, S. M. [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)

2011-09-09

207

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

PubMed

This paper presents improvements on a previously reported method for the measurement of elements in breast tissue specimens (Geraki et al 2002 Phys. Med. Biol. 47 2327-39). A synchrotron-based system was used for the detection of the x-ray fluorescence (XRF) emitted from iron, copper, zinc and potassium in breast tissue specimens, healthy and cancerous. Calibration models resulting from the irradiation of standard aqueous solutions were used for the quantification of the elements. The present developments concentrate on increasing the convergence between the tissue samples and the calibration models, therefore improving accuracy. For this purpose the composition of the samples in terms of adipose and fibrous tissue was evaluated, using an energy dispersive x-ray diffraction (EDXRD) system. The relationships between the attenuation and scatter properties of the two tissue components and water were determined through Monte Carlo simulations. The results from the simulations and the EDXRD measurements allowed the XRF data from each specimen to be corrected according to its composition. The statistical analysis of the elemental concentrations of the different groups of specimens reveals that all four elements are found in elevated levels in the tumour specimens. The increase is less pronounced for iron and copper and most for potassium and zinc. Other observed features include the substantial degree of inhomogeneity of elemental distributions within the volume of the specimens, varying between 4% and 36% of the mean, depending on the element and the type of the sample. The accuracy of the technique, based on the measurement of a standard reference material, proved to be between 3% and 22% depending on the element, which presents only a marginal improvement (1%-3%) compared to the accuracy of the previously reported results. The measurement precision was between 1% and 9% while the calculated uncertainties on the final elemental concentrations ranged between 10% and 16%. PMID:14971775

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

2004-01-01

208

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

NASA Astrophysics Data System (ADS)

This paper presents improvements on a previously reported method for the measurement of elements in breast tissue specimens (Geraki et al 2002 Phys. Med. Biol. 47 2327-39). A synchrotron-based system was used for the detection of the x-ray fluorescence (XRF) emitted from iron, copper, zinc and potassium in breast tissue specimens, healthy and cancerous. Calibration models resulting from the irradiation of standard aqueous solutions were used for the quantification of the elements. The present developments concentrate on increasing the convergence between the tissue samples and the calibration models, therefore improving accuracy. For this purpose the composition of the samples in terms of adipose and fibrous tissue was evaluated, using an energy dispersive x-ray diffraction (EDXRD) system. The relationships between the attenuation and scatter properties of the two tissue components and water were determined through Monte Carlo simulations. The results from the simulations and the EDXRD measurements allowed the XRF data from each specimen to be corrected according to its composition. The statistical analysis of the elemental concentrations of the different groups of specimens reveals that all four elements are found in elevated levels in the tumour specimens. The increase is less pronounced for iron and copper and most for potassium and zinc. Other observed features include the substantial degree of inhomogeneity of elemental distributions within the volume of the specimens, varying between 4% and 36% of the mean, depending on the element and the type of the sample. The accuracy of the technique, based on the measurement of a standard reference material, proved to be between 3% and 22% depending on the element, which presents only a marginal improvement (1%-3%) compared to the accuracy of the previously reported results. The measurement precision was between 1% and 9% while the calculated uncertainties on the final elemental concentrations ranged between 10% and 16%.

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

2004-01-01

209

X-Ray Fluorescence (XRF) spectrometry for materials analysis and discovering "the atomic number"  

NSDL National Science Digital Library

In this experiment students use XRF spectroscopy to analyze a sampleās elemental composition. From the characteristic X-ray energies, Moseleyās Law, a proof of the existence of the atomic number, is verified. The atomic number increases in regular steps with an increase in the characteristic X-ray energy. We will use this relationship to find the Rydbergās energy constant and screening coefficient for K X-rays. This lab is designed for the student to learn to: 1. differentiate between characteristic X-rays and Bremsstrahlung radiations, 2. use characteristic X-rays to identify elements, 3. acquire a spectrum, calibrate it and use it for qualitative (element identification) as well as quantitative (elemental concentration) analysis, and finally, 4. verify Moseleyās law and the validity of an atomic number.

Khalid, Asma; Khan, Aleena T.; Anwar, Muhammad S.

2012-06-06

210

Low-energy X-ray fluorescence microscopy opening new opportunities for bio-related research  

PubMed Central

Biological systems are unique matter with very complex morphology and highly heterogeneous chemical composition dominated by light elements. Discriminating qualitatively at the sub-micrometer level the lateral distribution of constituent elements, and correlating it to the sub-cellular biological structure, continues to be a challenge. The low-energy X-ray fluorescence microspectroscopy, recently implemented in TwinMic scanning transmission mode, has opened up new opportunities for mapping the distribution of the light elements, complemented by morphology information provided by simultaneous acquisition of absorption and phase contrast images. The important new information that can be obtained in bio-related research domains is demonstrated by two pilot experiments with specimens of interest for marine biology and food science. They demonstrate the potential to yield important insights into the structural and compositional enrichment, distribution and correlation of essential trace elements in the lorica of Tintinnopsis radix, and the lateral distribution of trace nutrients in the seeds of wheat Triticum aestivum.

Kaulich, Burkhard; Gianoncelli, Alessandra; Beran, Alfred; Eichert, Diane; Kreft, Ivan; Pongrac, Paula; Regvar, Marjana; Vogel-Mikus, Katarina; Kiskinova, Maya

2009-01-01

211

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

212

An X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) investigation in human and animal fossil bones from Holocene to Middle Triassic  

Microsoft Academic Search

We examined by Rietveld refinement of X-ray Diffraction patterns a series of 61 human and animal fossil bones in an age range from present time to Middle Triassic (around 245Ma). This approach, supplemented by elemental analysis according to X-ray Fluorescence, has permitted to obtain a quantitative evaluation of the mineralogical phases in the specimens, thus allowing to reconstruct the mineralization

Giampaolo Piga; Andrés Santos-Cubedo; Salvador Moya Solą; Antonio Brunetti; Assumpciņ Malgosa; Stefano Enzo

2009-01-01

213

X-ray fluorescence computed tomography (XFCT) imaging of gold nanoparticle-loaded objects using 110 kVp x-rays  

Microsoft Academic Search

A conventional x-ray fluorescence computed tomography (XFCT) technique requires monochromatic synchrotron x-rays to simultaneously determine the spatial distribution and concentration of various elements such as metals in a sample. However, the synchrotron-based XFCT technique appears to be unsuitable for in vivo imaging under a typical laboratory setting. In this study we demonstrated, for the first time to our knowledge, the

Seong-Kyun Cheong; Bernard L. Jones; Arsalan K. Siddiqi; Fang Liu; Nivedh Manohar; Sang Hyun Cho

2010-01-01

214

X-Ray Spectroscopic Laboratory Experiments in Support of the X-Ray Astronomy Program  

NASA Technical Reports Server (NTRS)

Our program is to perform a series of laboratory investigations designed to resolved significant atomic physics uncertainties that limit the interpretation of cosmic X-ray spectra. Specific goals include a quantitative characterization of Fe L-shell spectra; the development of new techniques to simulate Maxwellian plasmas using an Electron Beam Ion Trap (EBIT); and the measurement of dielectronic recombination rates for photoionized gas. New atomic calculations have also been carried out in parallel with the laboratory investigations.

Kahn, Steven M.

1997-01-01

215

Results of the Apollo 15 and 16 X-ray experiment  

NASA Technical Reports Server (NTRS)

Except for some minor modifications the Apollo 16 X-ray fluorescence experiment was similar to that flown aboard Apollo 15. The Apollo 16 provided data for a number of features not previously covered such as Mare Cognitum, Mare Nubium, Ptolemaeus, Descartes, Mendeleev, and other areas. Many data points were obtained by the X-ray experiments, so that comparisons could be drawn between Apollo 15 and 16 flights. The agreement was generally within about 10%. Al/Si concentration ratios ranged from 0.38% in Mare Cognitum to 0.67% in the Descartes area highlands. A comparison of the Apollo 16 data Al/Si values with optical albedo values along the ground tracks showed the same positive correlation as in the Apollo 15 flight. A reexamination of the detector and collimator geometries showed that the spatial resolution was better by almost a factor of two than the initial estimates.

Adler, I.; Trombka, J. I.; Schmadebeck, R.; Lowman, P.; Blodget, H.; Yin, L.; Eller, E.; Podwysocki, M.; Weidner, J. R.; Bickel, A. L.

1973-01-01

216

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

SciTech Connect

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

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

2009-01-01

217

Development of a new total reflection X-ray fluorescence instrument using polycapillary X-ray lens  

NASA Astrophysics Data System (ADS)

A new TXRF instrument combined with micro-XRF analytical technique was proposed. An X-ray micro-beam was obtained by using a polycapillary X-ray lens. The evaluated diameter of the X-ray beam at the focal distance was 35 ?m. In order to satisfy the total reflection condition of the present instrument, we attempted to cut the X-ray micro-beam above the critical angle of the total reflection with a slit. After the slit was applied, a clear critical angle could be observed. Using this proposed instrumental setup, we applied this to the analysis of a single particle on a flat Si substrate.

Nakano, K.; Tanaka, K.; Ding, X.; Tsuji, K.

2006-11-01

218

Grazing exit micro X-ray fluorescence analysis of a hazardous metal attached to a plant leaf surface using an X-ray absorber method.  

PubMed

If human beings or animals repeatedly ingest plant leaves contaminated with minute quantities of hazardous metals (Pb, As, Hg, Cd, etc.), the metals will gradually accumulate in their bodies. When the quantities of the metals in the bodies reach toxic levels, they may cause serious symptoms of poisoning. Therefore, it is significant to detect and analyze the minute quantities of hazardous metals that attach to plant leaves in terms of epidemiology and disease prevention. We developed grazing exit micro X-ray fluorescence analysis (GE-micro-XRF), which was expected to analyze the localized surface of an aqueous plant leaf with a much faster and simpler sample treatment than with conventional analytical methods, to detect Pb attached to a surface of a leaf of Camellia hiemalis. A micro X-ray beam was produced by using a polycapillary X-ray lens. GE-v-XRF is a grazing exit X-ray analysis (GE-XA) method in which X-rays emitted from only the near-surface region of a specimen are selectively detected under a grazing exit angle condition (extremely low exit angle near 0 degrees). In any GE-XA method, X-rays emitted from inside the specimen must be absorbed inside the specimen and attenuated when X-rays pass through the specimen. However, we deduced that X-rays emitted from inside aqueous organic material such as a plant leaf are scarcely absorbed because X-ray absorption in any aqueous organic material is much smaller than that in most metallic and semiconductor materials, which was analyzed with GE-XA methods. Therefore, we have developed a novel GE-micro-XRF method in which a chip of a silicon wafer is placed between the analyzed leaf and an X-ray detector as an absorber of the X-rays emitted from inside the leaf. As a result of GE-XRF analysis of a leaf dipped in Pb standard solution using the X-ray absorber, we have for the first time selectively detected X-rays emitted from the near-surface region of an aqueous plant leaf. Therefore, we have detected X-rays emitted from Pb with much higher peak/background ratios (P/B ratios) as compared to those of conventional XRF analysis. In the analysis, we also found a difference in element distributions between the leaf surface and its interior. Therefore, we observed and analyzed a cross section of the leaf with a SEM-EDX to confirm the validity of this result. The result of the analysis of the cross section has been in excellent agreement with that of the XRF analysis. PMID:19402720

Awane, Tohru; Fukuoka, Shintaro; Nakamachi, Kazuo; Tsuji, Kouichi

2009-05-01

219

Alignment of low-dose X-ray fluorescence tomography images using differential phase contrast.  

PubMed

X-ray fluorescence nanotomography provides unprecedented sensitivity for studies of trace metal distributions in whole biological cells. Dose fractionation, in which one acquires very low dose individual projections and then obtains high statistics reconstructions as signal from a voxel is brought together (Hegerl & Hoppe, 1976), requires accurate alignment of these individual projections so as to correct for rotation stage runout. It is shown here that differential phase contrast at 10.2?keV beam energy offers the potential for accurate cross-correlation alignment of successive projections, by demonstrating that successive low dose, 3?ms per pixel, images acquired at the same specimen position and rotation angle have a narrower and smoother cross-correlation function (1.5 pixels FWHM at 300?nm pixel size) than that obtained from zinc fluorescence images (25 pixels FWHM). The differential phase contrast alignment resolution is thus well below the 700?nm × 500?nm beam spot size used in this demonstration, so that dose fractionation should be possible for reduced-dose, more rapidly acquired, fluorescence nanotomography experiments. PMID:24365941

Hong, Young Pyo; Gleber, Sophie-Charlotte; O'Halloran, Thomas V; Que, Emily L; Bleher, Reiner; Vogt, Stefan; Woodruff, Teresa K; Jacobsen, Chris

2014-01-01

220

Photon regeneration experiment for axion search using x-rays.  

PubMed

In this Letter we describe our novel photon regeneration experiment for the axionlike particle search using an x-ray beam with a photon energy of 50.2 and 90.7 keV, two superconducting magnets of 3 T, and a Ge detector with a high quantum efficiency. A counting rate of regenerated photons compatible with zero has been measured. The corresponding limits on the pseudoscalar axionlike particle-two-photon coupling constant is obtained as a function of the particle mass. Our setup widens the energy window of purely terrestrial experiments devoted to the axionlike particle search by coupling to two photons. It also opens a new domain of experimental investigation of photon propagation in magnetic fields. PMID:21231567

Battesti, R; Fouché, M; Detlefs, C; Roth, T; Berceau, P; Duc, F; Frings, P; Rikken, G L J A; Rizzo, C

2010-12-17

221

Photon Regeneration Experiment for Axion Search Using X-Rays  

SciTech Connect

In this Letter we describe our novel photon regeneration experiment for the axionlike particle search using an x-ray beam with a photon energy of 50.2 and 90.7 keV, two superconducting magnets of 3 T, and a Ge detector with a high quantum efficiency. A counting rate of regenerated photons compatible with zero has been measured. The corresponding limits on the pseudoscalar axionlike particle-two-photon coupling constant is obtained as a function of the particle mass. Our setup widens the energy window of purely terrestrial experiments devoted to the axionlike particle search by coupling to two photons. It also opens a new domain of experimental investigation of photon propagation in magnetic fields.

Battesti, R.; Fouche, M.; Berceau, P.; Duc, F.; Frings, P.; Rikken, G. L. J. A.; Rizzo, C. [Laboratoire National des Champs Magnetiques Intenses (UPR 3228, CNRS-INSA-UJF-UPS), F-31400 Toulouse Cedex (France); Detlefs, C.; Roth, T. [European Synchrotron Radiation Facility, F-38043 Grenoble (France)

2010-12-17

222

Radiochemical Analysis by High Sensitivity Micro X-Ray Fluorescence Detection  

SciTech Connect

The primary objective of the project was to develop a novel dual-optic x-ray fluorescence instrument capable of doing radiochemical analysis of high-level radioactive wastes at DOE sites such as Savannah River Site and Hanford Site.

Ning Gao

2006-05-12

223

From papyrus to paper: Elemental characterization by X-ray fluorescence spectrometry  

Microsoft Academic Search

The use of the elemental composition, determined by energy dispersive X-ray fluorescence (EDXRF), to characterize ancient and modern papyrus and parchment, and newspaper from three different years is reported. The concentrations of S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Ga, As, Br, Rb, Sr, Ba and Pb were determined in these samples in order to proceed to its

M. Manso; M. Costa; M. L. Carvalho

2007-01-01

224

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

ERIC Educational Resources Information Center

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

Palmer, Peter T.

2011-01-01

225

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

Microsoft Academic Search

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

Wheeler

1982-01-01

226

Direct determination of 25 elements in dry powdered plant materials by X-ray fluorescence spectrometry  

Microsoft Academic Search

An X-ray fluorescence spectrometric (XRF) method has been developed for the direct determination of Na, Mg, Al, Si, P, S, K, Cl, Ca, Ti, Mn, Fe, Cu, Ni, Zn, Pb, Rb, Sr, Mo, Ba, Br, V, Cr, Co and As in plant samples using the pressed powder pellet technique, which uses 1 g of the dry powdered material. Correction for

Guohui Li; Shouzhong Fan

1995-01-01

227

X-RAY FLUORESCENCE ANALYSIS OF STAINLESS STEEL IN AQUEOUS SOLUTIONS  

Microsoft Academic Search

Nickel, chromium, molybdenum, and niobium were determined in aqueous ; solutions of stainless steels by x-ray fluorescence spectrometry. Nickel, ; chromium, and molybdenum are determined directly in solution, while niobium is ; separated by conversion to NbāOā and determined after briquetting ; with cellulose powder. The method is considerably faster than conventional ; wetchemical techniques and gives results which are

R. W. Jones; R. W. Ashley

1959-01-01

228

Detection of Fingerprints Based on Elemental Composition Using Micro-X-Ray Fluorescence  

Microsoft Academic Search

A method was developed to detect fingerprints using a technique known as micro-X-ray fluorescence. The traditional method of detecting fingerprints involves treating the sample with certain powders, liquids, or vapors to add color to the fingerprint so that it can be easily seen and photographed for forensic purposes. This is known as contrast enhancement, and a multitude of chemical processing

C. G. Worley; S. Wiltshire; T. C. Miller; G. J. Havrilla; V. Majidi

2005-01-01

229

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

Microsoft Academic Search

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

1988-01-01

230

SPECIMEN PREPARATION LIMITATIONS IN TRACE ELEMENT ANALYSIS QUANTIFICATION USING MICRO-X-RAY FLUORESCENCE  

Microsoft Academic Search

Micro-X-ray fluorescence, MXRF, has significant potential for trace elemental analysis when combined with proper specimen preparation. The combination of preconcentration with localized spatially resolved excitation offers increased sensitivity for both aqueous solutions and solid matrices. An additional attractive feature of MXRF is the small specimen size required. Present studies are directed towards the application of this method to trace elemental

Lisa P. Colletti; George J. Havrilla

231

X-ray fluorescence analysis of malachite ore concentrates in the Narman region  

Microsoft Academic Search

Analysis by energy dispersive X-ray fluorescence (EDXRF) spectroscopy of malachite ore of the Narman region in the city of Erzurum (Turkey) has been carried out for the determination of their elemental composition, using an annular 241Am radioisotope source. The elements Fe, Cu, Sr, Zr, In, Sn, Sb, I and Ba are analyzed. Samples are prepared from powder sifted by a

G. Budak; A Karabulut

1999-01-01

232

DETERMINATION OF CHLORIDE IN BERYLLIUM METAL BY X-RAY FLUORESCENCE  

Microsoft Academic Search

X-ray fluorescent analysis was applied to the determination of microgram ; quantities of chloride in beryllium metal powder. This application is preferable ; to wet-chemistry applications because of the speed and simplicity of analysis. ; Evaluation of the method consisted of pipetting a standard chloride solution on ; beryllium metal powder, drying, pressing into pellets, and analyzing. Analysis ; of

J. H. Keyes; J. H. Rowan

1963-01-01

233

Determination of Ti, Cr, Cu and Ta in Niobium Oxide by X-Ray Fluorescence Method.  

National Technical Information Service (NTIS)

An x-ray fluorescence method for the determination of Ti, Cr, Cu and Ta in niobium oxide has been developed. Samples/standards in powder form are mixed with boric acid in the proportion of 1:1 (400 mg. each). Double layer pellets are prepared by pressing ...

1986-01-01

234

X-RAY FLUORESCENCE ANALYSIS OF FILTER-COLLECTED AEROSOL PARTICLES  

EPA Science Inventory

X-ray fluorescence (XRF) has become an effective technique for determining the elemental content of aerosol samples. For quantitative analysis, the aerosol particles must be collected as uniform deposits on the surface of Teflon membrane filters. An energy dispersive XRF spectrom...

235

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

Microsoft Academic Search

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

Christopher G. Worley; George J. Havrilla

2000-01-01

236

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

Microsoft Academic Search

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

W. D. Wilhide; D. H. Ash

1985-01-01

237

Analysis of major, minor and trace elements in coal by radioisotope X-ray fluorescence spectrometry  

Microsoft Academic Search

The evaluation of the energy dispersive X-ray fluorescence spectroscopy method, for the analysis of major, minor and trace elements present in the mineral matter of coal, using an apparatus with sources of radioisotope elements, is described. Analyses were performed on both coal and coal ash samples and the results were compared. From these results it can be concluded that, the

G. P Suarez-Fernandez; J. M. G Vega; A. B Fuertes; A. B Garcia; M. R Mart??nez-Tarazona

2001-01-01

238

An interlaboratory comparison of bone lead measurements via K-shell x-ray fluorescence  

Microsoft Academic Search

Bone lead measurements assess chronic exposure and can be obtained via a noninvasive analytical technique based on K-she ll x-ray fluorescence (KXRF) spectrometry. While KXRF has been practiced by a number of laboratories around the world, this technique has not, until now, undergone an assessment of interlaboratory agreement. The study described here provides such an assessment via circulation of nine

X-RAY SPECTROMETRY; P. J. Parsons; D. J. Bellis; K. M. Hetter; C. Geraghty; N. A. Berglind; N. R. Ginde; P. Mata

2008-01-01

239

Total reflection X-ray fluorescence spectrometers for multielement analysis: status of equipment  

Microsoft Academic Search

Multielement analysis by total reflection X-ray fluorescence spectrometry has evolved during two decades. At present commercial equipment is available for chemical analysis of all types of biological and mineral samples. The electronic industry has also benefited from scientific and technological developments in this field due to new instrumentation to determine contamination on the surface of silicon wafers (the equipment will

Rony E. Ayala Jiménez

2001-01-01

240

Investigation of change of mineral metabolism of cosmonauts by X-ray fluorescence method  

Microsoft Academic Search

Micro-element determination was carried out in the blood serum and in the hair samples of the first Soviet—Hungarian space\\u000a team, by using the techniques of X-ray fluorescence analysis. The concentration of Cl, K, Ca, Br, Cu and Zn was determined\\u000a before and after the space flight.

J. Bacsó; M. Kis-Varga; P. Kovįcs; J. Pįlvölgyi; D. Berényi; J. Hideg; R. A. Tigranjan; T. A. Viting

1982-01-01

241

Mapping Metal Elements of Shuangbai Dinosaur Fossil by Synchrotron X-ray Fluorescence Microprobe  

Microsoft Academic Search

The metal elements mapping of Shuangbai dinosaur fossil, was obtained by synchrotron x-ray fluorescence (SXRF). Eight elements, Ca, Mn, Fe, Cu, Zn, As, Y and Sr were determined. Elements As and Y were detected for the first time in the dinosaur fossil. The data indicated that metal elements are asymmetrical on fossil section. This is different from common minerals. Mapping

Y. Wang; Y Qun; J Ablett

2008-01-01

242

Correction for beam attenuation and indirect excitation in x-ray fluorescence holography  

NASA Astrophysics Data System (ADS)

The influence of beam attenuation (BA) and indirect excitation (IE) processes on atomic resolved imaging with x-ray fluorescence holography (XFH) is considered. It is shown that these processes can influence element sensitivity, the key feature of XFH. A model which allows one to correct for BA and IE is proposed and verified experimentally.

Dul, D. T.; Dabrowski, K. M.; Korecki, P.

2013-12-01

243

Clinical Usefulness of Thyroid Imaging by Means of X-Ray Fluorescence  

Microsoft Academic Search

Iodine storage is an important thyroid function which has been difficult to estimate by simple means up to now. The introduction of the X-ray fluorescence technique makes this assessment possible on a large scale, with a minimum radiation burden and no more discomfort for the patient than classical imaging with radioisotopes. Its implementation has resulted in the better understanding of

Marc H. Jonckheer

1987-01-01

244

Results of x-ray fluorescence measurements at Riso, Task 3. High Burnup Effects Program.  

National Technical Information Service (NTIS)

The Xe distribution has been measured by X-ray fluorescence (XRF) in a total of 3 rim planks, i.e. longitudinal sections near the fuel rim, and 5 center planks, which are longitudinal sections containing the fuel center. The purpose of the rim plank measu...

M. Mogensen N. H. Anderson

1989-01-01

245

CHARACTERIZATION OF CHROMIUM-CONTAMINATED SOILS USING FIELD-PORTABLE X-RAY FLUORESCENCE  

EPA Science Inventory

A detailed characterization of the underlying and adjacent soils near a chrome plating shop utilized field-portable X- ray fluorescence (XRF) as a screening tool. XRF permitted real-time acquisition of estimates for total metal content of soils. A trailer-mounted soil coring unit...

246

Determining Cerium in Plutonium by Anion Exchange and X-ray Fluorescence.  

National Technical Information Service (NTIS)

This report describes a procedure for determining cerium in plutonium using an anion-exchange separation and x-ray fluorescence. We add lanthanum to the plutonium solution as an internal standard, oxidize the plutonium to Pu(+4), and pass the solution thr...

C. J. Martell J. M. Hansel

1988-01-01

247

Filter-fluorescer measurement of low-voltage simulator x-ray energy spectra  

SciTech Connect

X-ray energy spectra of the Maxwell Laboratories MBS and Physics International Pulserad 737 were measured using an eight-channel filter-fluorescer array. The PHOSCAT computer code was used to calculate channel response functions, and the UFO code to unfold spectrum.

Baldwin, G.T.; Craven, R.E.

1986-01-01

248

EVALUATION OF A PROTOTYPE FIELD-PORTABLE X-RAY FLUORESCENCE SYSTEM FOR HAZARDOUS WASTE SCREENING  

EPA Science Inventory

A prototype field-portable X-ray fluorescence system developed by EPA and NASA was evaluated at a site contaminated with Pb, Zn, and Cu. The objective of the field test was to evaluate the effectiveness of the instrument as a field analytical tool for locating hot spots and as a ...

249

SCANNING ELECTRON MICROSCOPY/X-RAY FLUORESCENCE CHARACTERIZATION OF POST-ABATEMENT DUST  

EPA Science Inventory

Scanning electron microscopy (SEM) and laboratory X-ray fluorescence (XRF) were used to characterize post-abatement dust collected with a HEPA filtered vacuum. hree size fractions of resuspended dust (0-30 pm, 2.5-15 pm, and ...

250

X-Ray Fluorescence Spectrometry of Itokawa and its implication to meteorite connection  

NASA Astrophysics Data System (ADS)

The CCD-based X-ray spectrometer XRS onboard Hayabusa has performed X-ray fluorescence spectrometry of the S- IV class near-Earth asteroid 25143 Itokawa to determine major elemental composition of the asteroid during the rendezvous phase We present here the results of the XRS observation indicating that the surface of Itokawa has chondritic composition and that LL- or L-chondrites are most likely but H-chondrites or primitive achondrites cannot be rejected Remote X-ray fluorescence or XRF technique is an application of a well established XRF method in the laboratory but the excitation source is solar X-rays It has been proven by the Apollo missions to determine major elemental composition of the surface of atmosphere-less planets such as the Moon e g SMART-1 SELENE Cheng e Chandrayaan-1 the Mercury e g Messenger Bepi Colombo and the asteroids e g NEAR Shoemaker Hayabusa The surface composition of Itokawa has been analyzed through remote XRF spectrometry by compared method between the X-rays off the asteroid and the onboard standard sample We have calculated the surface elemental ratios of Mg Si and Al Si for some sites observed by XRS during relatively enhanced solar activity Furthermore under the assumption that the continuum component of X-rays at Si-Ka is dominantly by the solar scattered X-rays the absolute abundance of the Si and correspondingly Mg from Mg Si can be derived There are found relatively small regional variations in composition We have estimated averaged elemental ratios of Mg Si and Al Si indicating

Okada, T.; Shirai, K.; Yamamoto, Y.; Arai, T.; Ogawa, K.; Hosono, K.; Inoue, To.; Inoue, Ta.; Maruyama, Y.; Kato, M.

251

Fluorescence X-ray computed tomography (FXCT) using a position-sensitive CdTe detector  

NASA Astrophysics Data System (ADS)

This research involved a 3D simulation of a non-destructive test to detect fluorescence X-rays with a position-sensitive CdTe detector. Simulations were performed under various conditions and on different types of phantoms. All simulations were based on fluorescence X-ray computed tomography (FXCT) using a Monte Carlo method. In general, conventional computed tomography (CT) analyzes materials based on their attenuation coefficients, and is highly dependent on the densities of the materials; hence, discriminating between materials of similar density can be difficult, even if their atomic numbers differ. In this research, the material was exposed to an X-ray source, and the characteristic X-ray was measured by using a 2-dimensional (2D) CdTe planar detector array and was then used to reconstruct a 3-dimensional (3D) image. A 2D CdTe pixelated array has a large detection area and operates with a compact cooling device. Because atoms have their own characteristic X-ray energy spectra, our system was even able to discriminate between materials with similar densities, provided the materials were composed of elements with different atomic numbers. In this research, FXCT was applied to distinguish between various materials, and real-world simulations were performed to verify the feasibility of our system for non-destructive inspection applications.

Yoon, Changyeon; Lee, Wonho

2014-01-01

252

Characterization of a polycapillary focusing X-ray lens for application in spatially resolved EXAFS experiments  

Microsoft Academic Search

A dispersive extended-X-ray-absorption-fine-structure (EXAFS) spectrometer based on a polycapillary focusing X-ray lens (PFXRL), a position-sensitive proportional counter and a rotating anode X-ray source is designed. When the working voltage and current of a Mo rotating anode X-ray generator are 25kV and 100mA, respectively, it takes 6h to obtain the EXAFS spectrum of the Cu film. The experiments show that a

Tianxi Sun; Zhiguo Liu; Xunliang Ding

2007-01-01

253

Comparison of SR-excited X-ray fluorescence analysis with neutron activation analysis for hair and fiber  

Microsoft Academic Search

Human scalp hair and some kinds of vegetable and animal fibers were analyzed by means of the SR excited X-ray fluorescence\\u000a method (SRXFA) and the neutron activation method (NAA). Human hair samples collected from five males and five females were\\u000a washed by the IAEA method prior to analysis. In the SRXFA analysis, samples were excited by monochromated X-rays. Fluorescence\\u000a X-rays

Naoki Saitoh; Takao Suzuki; Tohru Kishi; Atsuo Iida; Yohichi Gohshi

1987-01-01

254

Minority additive distributions in a ceramic metal-halide arc lamp using high-energy x-ray induced fluorescence  

Microsoft Academic Search

X-ray induced fluorescence is used to measure the elemental densities of minority additives in a metal-halide arc contained inside a translucent ceramic envelope. A monochromatic x-ray beam from the Sector 1 Insertion Device beamline at the Advanced Photon Source is used to excite K-shell x-ray fluorescence in the constituents of a ceramic metal-halide arc lamp dosed with DyI3 and CsI.

J. J. Curry; H. G. Adler; S. D. Shastri; J. E. Lawler

2001-01-01

255

F-64 L Shell X-Ray Fluorescence Cross-Sections for Elements with 33 <= Z <= 50  

Microsoft Academic Search

Accurate experimental data regarding the X-ray fluorescence (XRF) cross sections and fluorescence yields are important in basic studies of nuclear and atomic processes leading to the emission of X-ray and Auger electrons. The data is also required for many practical applications like elemental analysis by x-ray emission technique, dosimetric computation for medical physics and irradiation processes (1). A systematic study

Veena Sharma; Nirmal Singh; Sanjeev Kumar

2009-01-01

256

X-ray fluorescence method for determining the thickness of an aluminum coating on steel  

Microsoft Academic Search

We have used an EDX-720 energy-dispersive x-ray fluorescence spectrometer to develop a technique for determining the thickness\\u000a of an aluminum coating deposited on steel 47 NKhR. We have calculated the mass absorption coefficients for absorption of the\\u000a fluorescent emission of nickel by the aluminum coating, where nickel is a major component of the substrate material. We have\\u000a established and present

N. I. Mashin; A. A. Leont’eva; A. N. Tumanova; A. A. Ershov

2011-01-01

257

High resolution x-ray fluorescence spectroscopy - a new technique for site- and spin-selectivity  

SciTech Connect

X-ray spectroscopy has long been used to elucidate electronic and structural information of molecules. One of the weaknesses of x-ray absorption is its sensitivity to all of the atoms of a particular element in a sample. Through out this thesis, a new technique for enhancing the site- and spin-selectivity of the x-ray absorption has been developed. By high resolution fluorescence detection, the chemical sensitivity of K emission spectra can be used to identify oxidation and spin states; it can also be used to facilitate site-selective X-ray Absorption Near Edge Structure (XANES) and site-selective Extended X-ray Absorption Fine Structure (EXAFS). The spin polarization in K fluorescence could be used to generate spin selective XANES or spin-polarized EXAFS, which provides a new measure of the spin density, or the nature of magnetic neighboring atoms. Finally, dramatic line-sharpening effects by the combination of absorption and emission processes allow observation of structure that is normally unobservable. All these unique characters can enormously simplify a complex x-ray spectrum. Applications of this novel technique have generated information from various transition-metal model compounds to metalloproteins. The absorption and emission spectra by high resolution fluorescence detection are interdependent. The ligand field multiplet model has been used for the analysis of K{alpha} and K{beta} emission spectra. First demonstration on different chemical states of Fe compounds has shown the applicability of site selectivity and spin polarization. Different interatomic distances of the same element in different chemical forms have been detected using site-selective EXAFS.

Wang, Xin [Univ. of California, Davis, CA (United States). Dept. of Applied Science]|[Lawrence Berkeley National Lab., CA (United States)

1996-12-01

258

In vivo X-ray fluorescence of lead in bone using K X-ray excitation with sup 109 Cd sources: Radiation dosimetry studies  

SciTech Connect

Independent experiments have been performed at two centers, to evaluate the dosimetric properties of their respective {sup 109}Cd K X-ray fluorescence (XRF) bone lead measurement systems. Measurements were made of the dose to several points on the skin of the lower leg, at the surface of the tibia, in the red marrow tibia cavity, at the midcalf, and in the abdominal region occupied by the conceptus. Overall agreement between the two data sets was found. Similarities and differences are discussed. The effective dose values for an in vivo measurement of tibia lead concentration in 1-, 5-, and 10-year-old and adult subjects were calculated from one data set to be 1,100, 420, 190, and 34/38 (male/female) nSv, respectively, for an in vivo median precision of 4.9 {mu}Pb (g bone mineral){sup {minus}1} for a 30-min adult measurement.

Todd, A.C.; McNeill, F.E. (Univ. of Maryland, Baltimore (United States)); Palethorpe, J.E.; Peach, D.E.; Chettle, D.R. (Regional Radiation Physics and Protection Service, Birmingham (United Kingdom)); Tobin, M.J.; Strosko, S.J.; Rosen, J.C. (Univ. of Pittsburgh, PA (United States))

1992-04-01

259

Automatic particulate sulfur measurements with a dichotomous sampler and on-line x-ray fluorescence analysis  

SciTech Connect

A rapid, sensitive, and accurate X-ray fluorescence method to analyze elemental sulfur concentrations in ambient aerosol samples is described. The method involves using a dichotomous sampler to acquire fine particulate samples on a continuous tape filter. Elemental sulfur analyses are performed immediately following acquisition using an X-ray fluorescence spectrometer. Results obtained from experimental applications of the method are reported.

Jaklevic, J.M.; Loo, B.W.; Fujita, T.Y.

1981-06-01

260

Quantitative analysis of single aerosol particles with confocal micro-X-ray fluorescence spectrometer  

NASA Astrophysics Data System (ADS)

A laboratory confocal micro-X-ray fluorescence (XRF) spectrometer based on polycapillary X-ray optics (PXRO) was proposed to carry out the quantitative XRF analysis of single aerosol particles with smaller sizes than that of focal spot of the PXRO. The PXRO in the detection channel can both increase the collecting angle of the detector and lower the minimum detection limits of the XRF spectrometer. In order to reduce the effects of the PXRO on the analysis results, the sensitivities were corrected using a Gaussian function for the quantitative XRF analysis of single aerosol particles.

Sun, Tianxi; Liu, Zhiguo; Li, Yude; Lin, Xiaoyan; Wang, Guangfu; Zhu, Guanghua; Xu, Qing; Luo, Ping; Pan, Qiuli; Liu, Hui; Ding, Xunliang

2010-10-01

261

Comparative study of X-ray fluorescence signal collection by collimators of two types  

NASA Astrophysics Data System (ADS)

The response signal collection functions in a confocal setup of the X-ray fluorescence (XRF) tomography have been modeled for a polycapillary collimator and a multichannel collimator fabricated by means of microelectronic technology (MT). The dimensions of the effective collection region for the two types of collimators are compared. For the MT-fabricated device, a fraction of X-ray photons transmitted due to the total external reflection from channel walls has been evaluated. It is shown that, for a proper choice of parameters, the contribution of these photons to the collection function is negligibly small.

Shabel'nikova, Ya. L.; Chukalina, M. V.

2012-05-01

262

Radioisotope X-ray fluorescence analysis of some elements in colemanite ore  

NASA Astrophysics Data System (ADS)

The standard addition method for the determination of As, Sr, In, Sn, Sb, I, Cs and Ba elements in colemanite ore of Bigadiē region in the city of Balikesir (Turkey) was applied by using an Energy Dispersive X-ray Fluorescence (EDXRF) system. Samples are prepared from powder sifted by a 300-mesh sieve. An annular 100 mCi 241Am radioactive source emitting 59.5 keV photons was used for excitation. The characteristic K X-rays of the different elements were detected with a Si(Li) detector. These results are presented and discussed in this paper.

Karabulut, A.; Budak, G.

2000-01-01

263

Surface extended x-ray absorption fine structure of low-Z absorbates using fluorescence detection  

SciTech Connect

Comparison of x-ray fluorescence yield (FY) and electron yield surface extended x-ray absorption fine structure spectra above the S K-edge for c(2 x 2) S on Ni(100) reveals an order of magnitude higher sensitivity of the FY technique. Using FY detection, thiophene (C/sub 4/H/sub 4/S) chemisorption on Ni(100) is studied with S coverages down to 0.08 monolayer. The molecule dissociates at temperatures as low as 100K by interaction with fourfold hollow Ni sites. Blocking of these sites by oxygen leaves the molecule intact.

Stoehr, J.; Kollin, E.B.; Fischer, D.A.; Hastings, J.B.; Zaera, F.; Sette, F.

1985-05-01

264

Milestone experiments for single pass UV/X-ray FELs  

NASA Astrophysics Data System (ADS)

In the past decade, significant advances have been made in the theory and technology of high brightness electron beams and single pass FELs. These developments facilitate the construction of practical UV and X-ray FELs and has prompted proposals to the DOE for the construction of such facilities. There are several important experiments to be performed before committing to the construction of dedicated user facilities. Two experiments are under construction in the IR, the UCLA self-amplified spontaneous emission experiment and the BNL laser seeded harmonic generation experiment. A multi-institution collaboration is being organized about a 210 MeV electron linac available at BNL and the 10 m long NISUS wiggler. This experiment will be done in the UV and will test various experimental aspects of electron beam dynamics, FEL exponential regime with gain guiding, start-up from noise, seeding and harmonic generation. These experiments will advance the state of FEL research and lead towards future dedicated users' facilities.

Ben-Zvi, Ilan

1995-02-01

265

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

National Technical Information Service (NTIS)

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

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

1989-01-01

266

Educational X-Ray Experiments and XRF Measurements with a Portable Setup Adapted for the Characterization of Cultural Heritage Objects  

ERIC Educational Resources Information Center

It is common to modify valuable, sophisticated equipment, originally acquired for other purposes, to adapt it for the needs of educational experiments, with great didactic effectiveness. The present project concerns a setup developed from components of a portable system for energy dispersive x-ray fluorescence spectroscopy (EDXRF). Two educational…

Sianoudis, I.; Drakaki, E.; Hein, A.

2010-01-01

267

Optimizing Monocapillary Optics for Synchrotron X-ray Diffraction, Fluorescence Imaging, and Spectroscopy Applications  

SciTech Connect

A number of synchrotron x-ray applications such as powder diffraction in diamond anvil cells, microbeam protein crystallography, x-ray fluorescence imaging, etc. can benefit from using hollow glass monocapillary optics to improve the flux per square micron on a sample. We currently draw glass tubing into the desired elliptical shape so that only one-bounce under total reflection conditions is needed to bring the x-ray beam to a focus at a 25 to 50 mm distance beyond the capillary tip. For modest focal spot sizes of 10 to 20 microns, we can increase the intensity per square micron by factors of 10 to 1000. We show some of the results obtained at CHESS and Hasylab with capillaries focusing 5 to 40 keV radiation, their properties, and how even better the experimental results could be if more ideal capillaries were fabricated in the future.

Bilderback, Donald H.; Kazimirov, Alexander; Gillilan, Richard; Cornaby, Sterling; Woll, Arthur; Zha, Chang-Sheng [CHESS, Wilson Laboratory, Cornell University, Ithaca, New York, 14853 (United States); Huang Rong [Center for Advanced Radiation Sources, U. of Chicago, Chicago, Illinois, 60637 (United States)

2007-01-19

268

Development of confocal X-ray fluorescence (XRF) microscopy at the Cornell high energy synchrotron source  

NASA Astrophysics Data System (ADS)

A confocal X-ray fluorescence microscope was built at the Cornell High Energy Synchrotron Source (CHESS) to obtain compositional depth profiles of historic paintings. The microscope consists of a single-bounce, borosilicate monocapillary optic to focus the incident beam onto the painting and a commercial borosilicate polycapillary lens to collect the fluorescent X-rays. The resolution of the microscope was measured by scanning a variety of thin metal films through this confocal volume while monitoring the fluorescence signal. The capabilities of the technique were then probed using test paint microstructures with up to four distinct layers, each having a thickness in the range of 10 80 microns. Results from confocal XRF were compared with those from stand-alone XRF and visible light microscopy of the paint cross-sections. A large area, high-resolution scanner is currently being built to perform 3D scans on moderately sized paintings.

Woll, A. R.; Mass, J.; Bisulca, C.; Huang, R.; Bilderback, D. H.; Gruner, S.; Gao, N.

2006-05-01

269

X-ray emission from the outer planets: Albedo for scattering and fluorescence of solar X rays  

Microsoft Academic Search

Soft X-ray emission has been observed from the low-latitude “disk” of both Jupiter and Saturn as well as from the auroral regions of these planets. The disk emission as observed by ROSAT, the Chandra X-Ray Observatory, and XMM-Newton appears to be uniformly distributed across the disk and to be correlated with solar activity. These characteristics suggest that the disk X

T. E. Cravens; J. Clark; A. Bhardwaj; R. Elsner; J. H. Waite Jr; A. N. Maurellis; G. R. Gladstone; G. Branduardi-Raymont

2006-01-01

270

X-ray emission from the outer planets: Albedo for scattering and fluorescence of solar X rays  

Microsoft Academic Search

Soft X-ray emission has been observed from the low-latitude ``disk'' of both Jupiter and Saturn as well as from the auroral regions of these planets. The disk emission as observed by ROSAT, the Chandra X-Ray Observatory, and XMM-Newton appears to be uniformly distributed across the disk and to be correlated with solar activity. These characteristics suggest that the disk X

T. E. Cravens; J. Clark; A. Bhardwaj; R. Elsner; J. H. Waite; A. N. Maurellis; G. R. Gladstone; G. Branduardi-Raymont

2006-01-01

271

ENVIRONMENTAL TECHNOLOGY VERFICATION REPORT - FIELD PORTABLE X-RAY FLUORESCENCE ANALYZER - TN SPECTRACE, TN 9000 AND TN PB FIELD PORTABLE X-RAY FLOURESCENCE ANALYZERS  

EPA Science Inventory

In April 1995, the U.S. Environmental Protection Agency (EPA) sponsored a demonstration of field portable X-ray fluorescence (FPXRF) analyzers. The primary objectives of this demonstration were to evaluate these analyzers for: (1) their analytical performance relative to standar...

272

Potential applications of polycapillary optics to polarized beam X-ray fluorescence analysis  

NASA Astrophysics Data System (ADS)

The Polarized beam X-ray fluorescence (XRF) technique has potential applications in elemental analysis in materials analysis and in-vivo. In this work, first micro X-ray fluorescence (MXRF) measurements were done using a focusing lens. Polarization can be used to reduce the background, to give a better minimum detection limit. Polarizing the beam, using scattering has a disadvantage of low intensity and white beam background. Beam polarized by diffraction after collimating lens gives better results. A suitable crystal satisfying Bragg's condition gives a monochromatic as well as polarized beam with good intensity. Using a polycapillary lens increases the intensity of the X-ray beam using a laboratory based X-ray source with compact experimental set-up. Experimental results confirm the decrease in background in the polarization direction and the improvement in minimum detectable limit using the polarized beam. Verification of calculated results from measurements allows optimization of a laboratory based system with respect to source, lens and geometry parameters. MDL as low as ppm for bulk samples are predicted.

Hussain, Abrar M.

273

Correlative VIS-fluorescence and soft X-ray cryo-microscopy/tomography of adherent cells  

PubMed Central

Soft X-ray cryo-microscopy/tomography of vitreous samples is becoming a valuable tool in structural cell biology. Within the ‘water-window’ wavelength region (2.34–4.37 nm), it provides absorption contrast images with high signal to noise ratio and resolution of a few tens of nanometer. Soft X-rays with wavelengths close to the K-absorption edge of oxygen penetrate biological samples with thicknesses in the micrometer range. Here, we report on the application of a recently established extension of the transmission soft X-ray cryo-microscope (HZB TXM) at the beamline U41-XM of the BESSY II electron storage ring by an in-column epi-fluorescence and reflected light cryo-microscope. We demonstrate the new capability for correlative fluorescence and soft X-ray cryo-microscopy/tomography of this instrument along a typical life science experimental approach – the correlation of a fluorophore-tagged protein (pUL34-GFP of pseudorabies virus, PrV, the nuclear membrane-anchored component of the nuclear egress complex of the Herpesviridae which interacts with viral pUL31) in PrV pUL34-GFP/pUL31 coexpressing mammalian cells, with virus-induced vesicular structures in the nucleus, expanding the nucleoplasmic reticulum. Taken together, our results demonstrate new possibilities to study the role of specific proteins in substructures of adherent cells, especially of the nucleus in toto, accessible to electron microscopy in thinned samples only.

Hagen, Christoph; Guttmann, Peter; Klupp, Barbara; Werner, Stephan; Rehbein, Stefan; Mettenleiter, Thomas C.; Schneider, Gerd; Grunewald, Kay

2012-01-01

274

Development of a new Planetary SCD-based X-Ray Fluorescence Spectrometer Package for in-situ Analysis  

NASA Astrophysics Data System (ADS)

We propose an X-Ray Fluorescence Instrument Package (XRF-X and XRF-ISM) in order to measure the composition of rock-surface materials from orbiter, lander, and rover-based systems directly and quantitatively. It is suited for all future missions to the Moon, but also to the Galilean Satellites or any other solid-surface solar system body without an atmosphere. Collected data will be used for constructing detailed geochemical maps of the target body's surface composition. The typical spectral range is 1 - 10 keV (1.2 - 0.12 nm) with no sharp limits, achieving a spectral resolution of 160 eV at 6 keV. At these conditions, elemental abundances of lighter elements (atomic no. 11-32, K-Lines) and heavier elements (atomic no. 33-80, L-lines) will be observable. This will allow for mapping concentrations of the main mineral- (and therefore rock-) forming elements of surface materials, in particular Na, Mg, Al, Si, K, Ca, Ti, Mn, and Fe. The spatial resolution (GSD) is 10 km/px at an orbit altitude of 50 km. The package consists of two subsystems: (1) the main instrument targeting at a body's surface (XRF-X), and (2) a zenith-pointing solar monitor which incorporates calibration targets for taking account of solar X-Rays and particles (XRF-ISM). Both instruments make use of Energy-Dispersive X-Ray Fluorescence (EDX) with solar X-Ray excitation to probe materials over arbitrary distances. By monitoring incident Solar X-Ray and potential particle flux through synchronous measurement of a calibration target, XRF-X measurements can be obtained even over long distances, e.g. from a lunar orbiter. A scalable and modular design allows for instrument adaptions to desired resolution, to weight and power-consumption constraints and to expected sun emission intensities. The design will also allow adaption for employment on different observation platforms. In the current laboratory setup, both experiments are developed using large-area swept charge devices (SCD) to allow for high X-Ray returns. The X-Ray spectra are acquired by single photon counting with nearly 100% quantum efficiency and on-board histograming (MCA). As of today, the laboratory components have passed TRL 4 and 5; TRL 6 is expected no later than end of 2014. Development is funded by the German Aerospace Agency under grant 50 JR 1303.

Fabel, Oliver; Köhler, Eberhard; Dreißigacker, Anne; Meyer, Matthias; van Gasselt, Stephan

2014-05-01

275

Bent Laue X-ray Fluorescence Imaging of Manganese in Biological Tissues--Preliminary Results  

SciTech Connect

Manganese (Mn) is not abundant in human brain tissue, but it is recognized as a neurotoxin. The symptoms of manganese intoxication are similar to Parkinson's disease (PD), but the link between environmental, occupational or dietary Mn exposure and PD in humans is not well established. X-ray Absorption Spectroscopy (XAS) and in particular X-ray fluorescence can provide precise information on the distribution, concentration and chemical form of metals. However the scattered radiation and fluorescence from the adjacent abundant element, iron (Fe), may interfere with and limit the ability to detect ultra-dilute Mn. A bent Laue analyzer based Mn fluorescence detection system has been designed and fabricated to improve elemental specificity in XAS imaging. This bent Laue analyzer of logarithmic spiral shape placed upstream of an energy discriminating detector should improve the energy resolution from hundreds of eV to several eV. The bent Laue detection system was validated by imaging Mn fluorescence from Mn foils, gelatin calibration samples and adult Drosophila at the Hard X-ray MicroAnalysis (HXMA) beamline at the Canadian Light Source (CLS). Optimization of the design parameters, fabrication procedures and preliminary experimental results are presented along with future plans.

Zhu Ying; Zhang Honglin [Biomedical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Bewer, Brian [Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, SK S7N 5E2 (Canada); Nichol, Helen; Chapman, Dean [Anatomy and Cell Biology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5 (Canada); Thomlinson, Bill [Office of the Vice President Research, University of Saskatchewan, 121 Research Drive, Saskatoon, SK S7N 1K2 (Canada)

2010-06-23

276

[Determination of LF-VD refining furnace slag by X ray fluorescence spectrometry].  

PubMed

Eight components, i.e. TFe, CaO, MgO, Al2O3, SiO2, TiO2, MnO and P2O5 in refining furnace slag were determined by X ray fluorescence spectrometer. Because the content of CaO was high, the authors selected 12 national and departmental grade slag standard samples and prepared a series of synthetic standard samples by adding spectrally pure reagents to them. The calibration curve is suitable to the sample analysis of CaO, MgO and SiO2 with widely varying range. Meanwhile, the points on the curve are even. The samples were prepared at high temperature by adding Li2B4O7 as flux. The experiments for the selection of the sample preparation conditions about strip reagents, melting temperature and dulition ratio were carried out. The matrix effects on absorption and enhancement were corrected by means of PH model and theoretical alpha coefficient. Moreover, the precision and accuracy experiments were performed. In comparison with chemical analysis method, the quantitative analytical results for each component are satisfactory. The method has proven rapid, precise and simple. PMID:15760041

Kan, Bin; Cheng, Jian-ping; Song, Zu-feng

2004-10-01

277

A microfluidic setup for studies of solid-liquid interfaces using x-ray reflectivity and fluorescence microscopy  

SciTech Connect

In this paper we present a concept for a microfluidic chamber optimized for x-ray reflectivity studies at solid-liquid interfaces. Experiments of this kind are usually considerably limited by strong beam attenuation due to interactions with the aqueous environment. First experiments at synchrotron sources using supported model membranes showed that the microfluidic setup yields a very effective solution for minimizing background scattering and beam absorption, which are often accompanied by radiation damage of biological samples. Additionally, the setup is also well suited for the application of fluorescence microscopy. The application of these two different techniques on the same sample offers unique possibilities for complementary studies.

Reich, Christian; Hochrein, Marion B.; Krause, Baerbel; Nickel, Bert [Department fuer Physik der Ludwig-Maximilians-Universitaet Muenchen, Geschwister-Scholl-Platz 1, D-80539 Munich (Germany); European Synchrotron Radiation Facility, Boite Postale 220, F-38043 Grenoble Cedex (France); Department fuer Physik der Ludwig-Maximilians-Universitaet Muenchen, Geschwister-Scholl-Platz 1, D-80539 Munich (Germany)

2005-09-15

278

From papyrus to paper: Elemental characterization by X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

The use of the elemental composition, determined by energy dispersive X-ray fluorescence (EDXRF), to characterize ancient and modern papyrus and parchment, and newspaper from three different years is reported. The concentrations of S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Ga, As, Br, Rb, Sr, Ba and Pb were determined in these samples in order to proceed to its characterization. From this work, we can conclude that the obtained results allow distinguishing modern and ancient documents by its elemental amount. It was observed, with few exceptions, that the modern samples present lower elemental concentration than the older ones. Furthermore, in the newspaper samples the number of detected elements depends on the newspaper's age, and decreases from the oldest (1919) to the most recent (2005). X-ray fluorescence spectrometry is a good elemental technique with the main advantage of being non-destructive, which makes it the perfect tool for the elemental analysis of cultural heritage.

Manso, M.; Costa, M.; Carvalho, M. L.

2007-09-01

279

X-ray fluorescence/Auger-electron coincidence spectroscopy of vacancy cascades in atomic argon  

SciTech Connect

Argon L{sub 2.3}-M{sub 2.3}M{sub 2.3} Auger-electron spectra were measured in coincidence with K{alpha} fluorescent x-rays in studies of Ar K-shell vacancy decays at several photon energies above the K-threshold and on the 1s-4p resonance in atomic argon. The complex spectra recorded by conventional electron spectroscopy are greatly simplified when recorded in coincidence with fluorescent x-rays, allowing a more detailed analysis of the vacancy cascade process. The resulting coincidence spectra are compared with Hartree-Fock calculations which include shake-up transitions in the resonant case. Small energy shifts of the coincidence electron spectra are attributed to post-collision interaction with 1s photoelectrons.

Arp, U. [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Electron and Optical Physics Div.; LeBrun, T.; Southworth, S.H.; Jung, M. [Argonne National Lab., IL (United States). Physics Div.; MacDonald, M.A. [E.P.S.R.C. Daresbury Lab., Warrington (United Kingdom)

1996-12-01

280

Application of X-ray Fluorescence Spectroscopy in Analysis of Oil Paint Pigments  

NASA Astrophysics Data System (ADS)

X-ray Fluorescence (XRF) spectroscopy is a rapid, noninvasive technique for both detecting and identifying chemical elements within a given sample. At North Georgia College and State University, a sealed tube x-ray source and slightly focusing polycapillary optic are used in nondestructive XRF analysis of oil paint pigments. Oil paints contain both organic and inorganic matter, and the inorganic ingredients such as titanium, vanadium, iron, zinc, and other elements are easily detected by XRF, which can be used to uniquely differentiate between various paint pigments. To calibrate the XRF system for paint color identification, six different colors of oil paint were fluoresced and identified based off of their characteristic spectra. By scanning the paint sample in two dimensions, the characteristic XRF spectra obtained were compiled to produce an XRF replica of the painting.

Major, Cassandra; Formica, Sarah

2011-10-01

281

Application of the Total Reflection X-ray Fluorescence technique to trace elements determination in tobacco  

NASA Astrophysics Data System (ADS)

Many studies have identified an important number of toxic elements along with organic carcinogen molecules and radioactive isotopes in tobacco. In this work we have analyzed by Total Reflection X-Ray Fluorescence 9 brands of cigarettes being manufactured and distributed in the Mexican market. Two National Institute of Standards and Technology standards and a blank were equally treated at the same time. Results show the presence of some toxic elements such as Pb and Ni. These results are compared with available data for some foreign brands, while their implications for health are discussed. It can be confirmed that the Total Reflection X-Ray Fluorescence method provides precise (reproducible) and accuracy (trueness) data for 15 elements concentration in tobacco samples.

Martinez, T.; Lartigue, J.; Zarazua, G.; Avila-Perez, P.; Navarrete, M.; Tejeda, S.

2008-12-01

282

X-ray Fluorescence Emission Tomography (XFET) with Novel Imaging Geometries - A Monte Carlo Study  

PubMed Central

This paper presents a feasibility study for using two new imaging geometries for synchrotron X-ray fluorescence emission tomography (XFET) applications. In the proposed approaches, the object is illuminated with synchrotron X-ray beams of various cross-sectional dimensions. The resultant fluorescence photons are detected by high-resolution imaging-spectrometers coupled to collimation apertures. To verify the performance benefits of the proposed methods over the conventional line-by-line scanning approach, we have used both Monte Carlo simulations and an analytical system performance index to compare several different imaging geometries. This study has demonstrated that the proposed XFET approach could lead to a greatly improved imaging speed, which is critical for making XFET a practical imaging modality for a wide range of applications.

Meng, L. J.; Li, Nan; La Riviere, P. J.

2011-01-01

283

The use of swept-charge devices in planetary analogue X-ray fluorescence studies  

NASA Astrophysics Data System (ADS)

The Chandrayaan-1 X-ray Spectrometer (C1XS) was launched onboard the Indian Space Research Organisation (ISRO) Chandrayaan-1 lunar mission in October 2008. The instrument consisted of 24 swept-charge device (SCD) silicon X-ray detectors providing a total collecting area of ~ 24 cm2, corresponding to a 14° field of view (FWHM), with the ability to measure X-rays from 0.8-10 keV. One algorithm used to analyse the C1XS flight data was developed at Rutherford Appleton Laboratory (RAL) to convert the raw X-ray flux data into elemental ratios and abundances to make geological interpretations about the lunar surface. Laboratory X-ray fluorescence (XRF) data were used to validate the RAL algorithm, with previous studies investigating how the measured XRF flux varies with target surface characteristics including grain size and roughness. Evidence for a grain-size effect was observed in the data, the XRF line intensity generally decreasing with increasing sample grain size, dependent on the relative abundance of elemental components. This paper presents a subsequent study using more homogeneous samples made from mixtures of MgO, Al2O3 and SiO2 powders, all of grain size < 44 ?m, across a broader range of mixture ratios and at a higher level of X-ray flux data in order to further validate the RAL algorithm. For the majority of the C1XS flight data analysed so far with the RAL algorithm, the corresponding lunar ground tracks have been generally basaltic, laboratory verification of the algorithm having been primarily conducted using basaltic lunar regolith simulant (JSC-1A) XRF data. This paper also presents results from tests on a terrestrial anorthosite sample, more relevant to the anorthositic lunar highlands, from where the remaining C1XS lunar dataset derives. The operation of the SCD, the XRF test facility, sample preparation and collected XRF spectra are discussed in this paper.

Walker, T. E.; Smith, D. R.

2012-07-01

284

Characterization of phosphorus in organisms at sub-micron resolution using X-ray fluorescence spectromicroscopy.  

SciTech Connect

X-ray spectromicroscopy (combined X-ray spectroscopy and microscopy) is uniquely capable of determining sub-micron scale elemental content and chemical speciation in minimally-prepared particulate samples. The high spatial resolutions achievable with this technique have enabled the close examination of important microscale processes relevant to the cycling of biogeochemically important elements. Here, we demonstrate the value of X-ray microscopy to environmental and biological research by examining the phosphorus and metal chemistry of complete individual cells from the algal genera Chlamydomonas sp. and Chlorella sp. X-ray analysis revealed that both genera store substantial intracellular phosphorus as distinct, heterogeneously distributed granules whose X-ray fluorescence spectra are consistent with that of polyphosphate. Polyphosphate inclusions ranged in size from 0.3-1.4 {micro}m in diameter and exhibited a nonspecies-specific average phosphorus concentration of 6.87 {+-} 1.86 {micro}g cm{sup -2}, which was significantly higher than the average concentration of phosphorus measured in the total cell, at 3.14 {+-} 0.98 {micro}g cm{sup -2} (95% confidence). Polyphosphate was consistently associated with calcium and iron, exhibiting average P:cation molar ratios of 8.31 {+-} 2.00 and 108 {+-} 34, respectively (95% confidence). In some cells, polyphosphate was also associated with potassium, zinc, manganese, and titanium. Based on our results, X-ray spectromicroscopy can provide high-resolution elemental data on minimally prepared, unsectioned cells that are unattainable through alternative microscopic methods and conventional bulk chemical techniques currently available in many fields of marine chemistry.

Diaz, J.; Ingall, E; Vogt, S; Paterson, D; DeJonge, M; Rao, C; Brandes, J

2009-01-01

285

Application of in situ x-ray absorption and fluorescence measurements to analyze solutions in a simulated pit  

SciTech Connect

X-ray energy-dispersive spectroscopy has been used to study the compositions of metal ions in solutions developed during localized corrosion. An electrochemical cell was designed to simulate a corrosion pit, maintaining one-dimensional diffusion and fulfilling the requirements for x-ray fluorescence measurements. The working electrode consisted of a dissolving thin foil of Type 304 stainless steel sealed between Mylar sheets through which the x-ray beam passed. Concentration gradients within the artificial pit were quantitatively determined.

Isaacs, H.S.; Davenport, A.J.; Cho, J.H. [Brookhaven National Lab., Upton, NY (United States); Rivers, M.L.; Sutton, S.R. [Chicago Univ., IL (United States). Dept. of Geophysical Sciences

1991-12-31

286

Application of in situ scanning x-ray fluorescence to study the concentration of metal ions in simulated pits  

SciTech Connect

X-ray energy-dispersive spectroscopy has been used to study the compositions of metal ions in solutions developed during localized corrosion. An electrochemical cell was designed to simulate a corrosion pit, maintaining one-dimensional diffusion and fulfilling the requirements for x-ray fluorescence measurements. The working electrode consisted of a dissolving thin foil of Type 304 stainless steel sealed between Mylar sheets through which the x-ray beam passed. Concentration gradients within the artifical pit were quantitatively determined.

Isaacs, H.S.; Davenport, A.J. [Brookhaven National Lab., Upton, NY (United States); Jeong-Hwan, Cho [Yonsei Univ., Seoul (Korea, Republic of). Dept. of Chemistry; Rivers, M.L.; Sutton, S.R. [Chicago Univ., IL (United States). Dept. of Geophysical Sciences

1993-06-01

287

Application of in situ x-ray absorption and fluorescence measurements to analyze solutions in a simulated pit  

SciTech Connect

X-ray energy-dispersive spectroscopy has been used to study the compositions of metal ions in solutions developed during localized corrosion. An electrochemical cell was designed to simulate a corrosion pit, maintaining one-dimensional diffusion and fulfilling the requirements for x-ray fluorescence measurements. The working electrode consisted of a dissolving thin foil of Type 304 stainless steel sealed between Mylar sheets through which the x-ray beam passed. Concentration gradients within the artificial pit were quantitatively determined.

Isaacs, H.S.; Davenport, A.J.; Cho, J.H. (Brookhaven National Lab., Upton, NY (United States)); Rivers, M.L.; Sutton, S.R. (Chicago Univ., IL (United States). Dept. of Geophysical Sciences)

1991-01-01

288

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

289

Investigation of polyelectrolytes by total reflection X-ray fluorescence spectrometry  

Microsoft Academic Search

Water soluble polyelectrolyte samples containing mono-, bi- and trivalent metal ions were investigated without any pretreatment. Acid digestion of linear polymers may lead to a product insoluble in water so the digestion has to be avoided. The determination of analytical characteristics and limitations of the total reflection X-ray fluorescence (TXRF) analysis for poly(vinylalcohol-vinylsulfate) copolymers containing the following cations: Cs+; Ba2+;

Imre Varga; Miklós Nagy

2001-01-01

290

Novel assessment of hepatic iron distribution by synchrotron radiation X-ray fluorescence microscopy  

Microsoft Academic Search

Excess iron deposition in the liver is known to be hepatotoxic and may exacerbate liver injury. However, little is known about\\u000a iron distribution in the lobule because of the lack of a highly sensitive detection method. The aim of this study is to determine\\u000a iron distribution in the lobule of human liver by means of synchrotron radiation X-ray fluorescence (SRXRF)

Hisoka Kinoshita; Yuichi Hori; Takumi Fukumoto; Takuji Ohigashi; Kunio Shinohara; Yoshitake Hayashi; Yonson Ku

2010-01-01

291

Radioisotope X-ray fluorescence analysis of some elements in colemanite ore  

Microsoft Academic Search

The standard addition method for the determination of As, Sr, In, Sn, Sb, I, Cs and Ba elements in colemanite ore of Bigadiē region in the city of Balikesir (Turkey) was applied by using an Energy Dispersive X-ray Fluorescence (EDXRF) system. Samples are prepared from powder sifted by a 300-mesh sieve. An annular 100 mCi 241Am radioactive source emitting 59.5

A. Karabulut; G Budak

2000-01-01

292

X-ray fluorescence spectrometric analysis of erbium oxide for rare earth impurities  

Microsoft Academic Search

An X-ray fluorescence spectrometric method has been developed for the analysis of high purity erbium oxide for the determination of yttrium, terbium, dysprosium, holmium, thulium, ytterbium and lutetium oxide impurities in the concentration range 0.005–0.1%. The sample is taken in oxalate form, mixed with a binder (boric acid) in the weight ratio 31 and made into a double layer pellet.

L. C. Chandola; P. P. Khanna

1985-01-01

293

Forensic application of total reflection X-ray fluorescence spectrometry for elemental characterization of ink samples  

Microsoft Academic Search

The possibility of applying Total Reflection X-ray Fluorescence for qualitative and quantitative differentiation of documents printed with rare earth tagged and untagged inks has been explored in this paper. For qualitative differentiation, a very small amount of ink was loosened from the printed documents by smoothly rubbing with a new clean blade without destroying the manuscript. 50?L of Milli-Q water

Sangita Dhara; N. L. Misra; S. D. Maind; Sanjukta A. Kumar; N. Chattopadhyay; S. K. Aggarwal

2010-01-01

294

Determination of rhenium in molybdenite by X-ray fluorescence: A combined chemical-spectrometric technique.  

PubMed

Rhenium in molybdenite is separated from molybdenum by distillation of rhenium heptoxide from a perchloric-sulphuric acid mixture. It is concentrated by precipitation of the sulphide and then determined by X-ray fluorescence. From 3 to 1000 microg of rhenium can be measured with a precision generally within 2%. The procedure tolerates larger amounts of molybdenum than the usual colorimetric methods. PMID:18960464

Solt, M W; Wahlberg, J S; Myers, A T

1969-01-01

295

Quantifying trace elements in individual aquatic protist cells with a synchrotron x-ray fluorescence microprobe  

Microsoft Academic Search

The study of trace metal cycling by aquatic protists is limited by current analytical techniques. Standard 'bulk' element analysis techniques that rely on physical separations to concentrate cells for analysis cannot separate cells from co-occurring detrital material or other cells of differing taxonomy or trophic function. Here we demonstrate the ability of a synchrotron-based X-ray fluorescence (SXRF) microprobe to quantify

Benjamin S. Twining; Stephen B. Baines; Nicholas S. Fisher; Jörg Maser; Stefan Vogt; Chris Jacobsen; Antonio Tovar-Sanchez; S. A. Sanudo-Wihelmy

2003-01-01

296

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

297

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

NASA Astrophysics Data System (ADS)

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

Worley, Christopher G.; Havrilla, George J.

2000-07-01

298

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

Microsoft Academic Search

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

E. I. Obiajunwa

2001-01-01

299

The reproducibility of [sup 109]Cd-based X-ray fluorescence measurements of bone lead  

Microsoft Academic Search

We assessed the reproducibility of X-ray fluorescence-based lead measurements from multiple measurements made on a low-concentration plaster of paris phantom and in five subjects measured five times on two occasions. Over a 6-month period, 220 measurements of the same phantom were obtained and showed a standard deviation of 1.29 [mu]g Pb (g plaster of paris)[sup [minus]1]. The two sets of

C. L. Gordon; C. E. Webber; D. R. Chettle

1994-01-01

300

Synchrotron X-ray Fluorescence Microtomography in Geo, Cosmo-, and Bio chemistry  

Microsoft Academic Search

Synchrotron-based X-ray fluorescence computed microtomography (xrfCMT) is a unique method for imaging major and trace element distributions within natural materials nondestructively and with high spatial resolution. The technique is particularly useful in imaging and quantifying elemental abundance in small objects that may be too precious or too difficult to section, or in the analysis of materials in which sectioning may

A. Lanzirotti; S. R. Sutton; M. Rivers; R. Tappero

2009-01-01

301

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

Microsoft Academic Search

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

J. F. Mucci; R. L. Stearns

1977-01-01

302

Continuous X-ray fluorescence analysis of iron ore mixtures in the production of agglomerate  

Microsoft Academic Search

A system is developed for the continuous control of the chemical composition of iron ore mixtures (IOMs) by X-ray fluorescence analysis (XRF) directly on the conveyor belt. The system was found to be efficient under the conditions of mining and smelting production\\u000a at the Magnitogorsk Metallurgical Combine. The proposed XRF method does not require sampling; provides the required accuracy;\\u000a and

N. V. Alov; A. I. Volkov; A. I. Usherov; E. N. Ishmets’ev; E. V. Usherova

2010-01-01

303

Tibial lead determination by 99Tcm radiopharmaceutical X-ray fluorescence  

Microsoft Academic Search

The feasibility of measuring tibial lead concentration by X-ray fluorescence with an internal 99Tcm labelled bone-seeking radiopharmaceutical was investigated using phantoms containing known values of lead concentration and 99Tcm activity. The minimum detectable concentration (MDC) at two standard deviations based on the counts in the Kalpha 1 peak of 10.9 mu g Pb ml-1 was estimated to correspond to an

P. J. Mountford; S. Green; D. A. Bradley; A. D. Lewis; W. D. Morgan

1994-01-01

304

X-ray fluorescence and electron microscopy study of plankton samples from the Novosibirsk reservoir  

Microsoft Academic Search

Five samples of plankton from the Novosibirsk reservoir are collected and analyzed by X-ray fluorescence. In combination with\\u000a high sensitive atomic absorption spectroscopy (AAS), inductively coupled plasma mass spectrometry (ICP-MS), and instrumental\\u000a neutron activation analysis (INAA), quantitative data on the concentrations of 52 chemical elements in plankton are obtained.\\u000a Scanning electron microscopy is used to analyze the elemental composition of

G. A. Leonova; V. A. Bobrov; E. V. Lazareva

2010-01-01

305

X-ray fluorescence microtomography- and polycapillary-based confocal imaging using synchrotron radiation  

Microsoft Academic Search

This work illustrates the development of X-ray fluorescence tomography and polycapillary based confocal imaging towards a three-dimensional (3D), quantitative analytical method with lateral resolution levels down to the 2-20 mum scale. Detailed analytical characterization is given for polycapillary based confocal XRF imaging, which is a new variant of the 3D micro-XRF technique. Applications for 2D\\/3D micro-XRF are illustrated for the

Laszlo Vincze; Bart Vekemans; Imre Szaloki; Frank E. Brenker; Gerald Falkenberg; Karen Rickers; Katrien Aerts; Rene Van Grieken; Freddy Adams

2004-01-01

306

Characterization of hypoglycemiant plants by total reflection X-ray fluorescence spectrometry  

Microsoft Academic Search

In this work, synchrotron radiation total reflection X-ray fluorescence spectrometry (SRTXRF) was used to determine trace\\u000a elements in eight hypoglycemiant plants (Trigonella foenum graecum, Panax ginseng, Pfaffia paniculata, Myrcia speciosa, Zea mays, Harpagophytum procumbens, Syzygium\\u000a jambolona, and Bauhinia forficate). The elements P, K, Ca, Ti, Mn, Fe, Cu, Zn, Rb, and Sr were detected in all medicinal plants investigated, whereas

Orghźda L. A. D. Zucchi; Silvana Moreira; Edgar F. O. de Jesus; Helio Salvio Neto; Marcos J. Salvador

2005-01-01

307

Multilayers quantitative X-ray fluorescence analysis applied to easel paintings  

Microsoft Academic Search

X-ray fluorescence spectrometry (XRF) allows a rapid and simple determination of the elemental composition of a material.\\u000a As a non-destructive tool, it has been extensively used for analysis in art and archaeology since the early 1970s. Whereas\\u000a it is commonly used for qualitative analysis, recent efforts have been made to develop quantitative treatment even with portable\\u000a systems. However, the interpretation

Laurence de Viguerie; V. Armando Sole; Philippe Walter

2009-01-01

308

Preconcentration Methods for the Analysis of Liquid Samples by X-Ray Fluorescence Techniques  

Microsoft Academic Search

This article gives an overview of the state-of-the-art of multi-element and single-element preconcentration procedures prior to X-ray fluorescence (XRF) analysis of liquid samples. Many of these preconcentration methods were developed long ago and the purpose of this review is to present some new efficient variations of these methods and new techniques extending the possibilities of XRF for liquid solutions analysis.

E. Margui; R. van Grieken; C. Fontas; M. Hidalgo; I. Queralt

2010-01-01

309

A NON-DESTRUCTIVE X-RAY FLUORESCENCE METHOD FOR ANALYSIS OF METAL ALLOY WIRE SAMPLES  

Microsoft Academic Search

Although quantitative analysis of metal alloys is typically accomplished by wet-chemical techniques, complete dissolution of some metal alloys can be difficult. Here, we report an alternative non-destructive energy-dispersive x-ray fluorescence (EDXRF) method for determination of nickel, gold, copper, and silver in metal alloy wires. Sample preparation is simple and consists of mounting wires as a single strand in machined polyethylene

Steven J. Goldstein; L. Dale Sivils

2001-01-01

310

ON THE SUITABILITY OF PORTABLE X-RAY FLUORESCENCE ANALYZERS FOR RAPID SCREENING OF TOXIC ELEMENTS  

Microsoft Academic Search

X-Ray Fluorescence spectrometry (XRF) has been routinely used for alloy testing, determination of Pb in paint, and determination of Cd in plastic. However, its use to screen for toxic elements in food and medicinal products has been surprisingly limited to date. While XRF is less sensitive than atomic spectrometry methods such as ICP-AES and ICP-MS, it offers a number of

Pete Palmer; Siri Webber; Kelly Ferguson

311

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

Microsoft Academic Search

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

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

2010-01-01

312

X-ray Fluorescence Determination of Element Contents in Milk and Dairy Products  

Microsoft Academic Search

The concentrations of minerals (Na, Mg, P, S, Cl, K, and Ca) and trace elements (Mn, Fe, Ni, Cu, Zn, Rb, Sr, and Br) in different\\u000a types of milk, dairy products, and infant formulas have been determined using wavelength-dispersive X-ray fluorescence analysis\\u000a (WDXRF). Freeze-dried samples pressed as tablets of 4 g have been analyzed. Calibrations have been established using both\\u000a plant

Galina V. Pashkova

2009-01-01

313

Development of suitable plastic standards for X-ray fluorescence analysis  

NASA Astrophysics Data System (ADS)

For the adoption of the EU directive "Restriction on use of certain Hazardous Substances" and "Waste Electrical and Electronic Equipment" using X-ray fluorescence analysis suitable standard materials are required. Plastic standards based on acrylonitrile-butadiene-styrene terpolymer, containing the regulated elements Br, Cd, Cr, Hg and Pb were developed and produced as granulates and solid bodies. The calibration materials were not generated as a dilution from one master batch but rather the element concentrations were distributed over nine independent calibration samples. This was necessary to enable inter-elemental corrections and empirical constant mass absorption coefficients. The produced standard materials are characterized by a homogenous element distribution, which is more than sufficient for X-ray fluorescence analysis. Concentrations for all elements except for Br could be determined by Inductively Coupled Plasma Atomic Emission Spectroscopy after microwave assisted digestion. The concentration of Br was determined by use of Neutron Activation Analysis at Hahn-Meitner-Institute in Berlin, Germany. The correlation of the X-ray fluorescence analysis measurements with the values determined using Inductively Coupled Plasma Atomic Emission Spectroscopy and Neutron Activation Analysis showed a very good linearity.

Mans, Christian; Hanning, Stephanie; Simons, Christoph; Wegner, Anne; Jan?en, Anton; Kreyenschmidt, Martin

2007-02-01

314

A method of measuring gold nanoparticle concentrations by x-ray fluorescence for biomedical applications  

SciTech Connect

Purpose: This paper reports a technique that enables the quantitative determination of the concentration of gold nanoparticles (GNPs) through the accurate detection of their fluorescence radiation in the diagnostic x-ray spectrum. Methods: Experimentally, x-ray fluorescence spectra of 1.9 and 15 nm GNP solutions are measured using an x-ray spectrometer, individually and within chicken breast tissue samples. An optimal combination of excitation and emission filters is determined to segregate the fluorescence spectra at 66.99 and 68.80 keV from the background scattering. A roadmap method is developed that subtracts the scattered radiation (acquired before the insertion of GNP solutions) from the signal radiation acquired after the GNP solutions are inserted. Results: The methods effectively minimize the background scattering in the spectrum measurements, showing linear relationships between GNP solutions from 0.1% to 10% weight concentration and from 0.1% to 1.0% weight concentration inside a chicken breast tissue sample. Conclusions: The investigation demonstrated the potential of imaging gold nanoparticles quantitatively in vivo for in-tissue studies, but future studies will be needed to investigate the ability to apply this method to clinical applications.

Wu Di; Li Yuhua; Wong, Molly D.; Liu Hong [Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States)

2013-05-15

315

X-ray fluorescence computed tomography (XFCT) imaging of gold nanoparticle-loaded objects using 110 kVp x-rays  

NASA Astrophysics Data System (ADS)

A conventional x-ray fluorescence computed tomography (XFCT) technique requires monochromatic synchrotron x-rays to simultaneously determine the spatial distribution and concentration of various elements such as metals in a sample. However, the synchrotron-based XFCT technique appears to be unsuitable for in vivo imaging under a typical laboratory setting. In this study we demonstrated, for the first time to our knowledge, the possibility of performing XFCT imaging of a small animal-sized object containing gold nanoparticles (GNPs) at relatively low concentrations using polychromatic diagnostic energy range x-rays. Specifically, we created a phantom made of polymethyl methacrylate plastic containing two cylindrical columns filled with saline solution at 1 and 2 wt% GNPs, respectively, mimicking tumors/organs within a small animal. XFCT scanning of the phantom was then performed using microfocus 110 kVp x-ray beam and cadmium telluride (CdTe) x-ray detector under a pencil beam geometry after proper filtering of the x-ray beam and collimation of the detector. The reconstructed images clearly identified the locations of the two GNP-filled columns with different contrast levels directly proportional to gold concentration levels. On the other hand, the current pencil-beam implementation of XFCT is not yet practical for routine in vivo imaging tasks with GNPs, especially in terms of scanning time. Nevertheless, with the use of multiple detectors and a limited number of projections, it may still be used to image some objects smaller than the current phantom size. The current investigation suggests several modification strategies of the current XFCT setup, such as the adoption of the quasi-monochromatic cone/fan x-ray beam and XFCT-specific spatial filters or pinhole detector collimators, in order to establish the ultimate feasibility of a bench-top XFCT system for GNP-based preclinical molecular imaging applications.

Cheong, Seong-Kyun; Jones, Bernard L.; Siddiqi, Arsalan K.; Liu, Fang; Manohar, Nivedh; Cho, Sang Hyun

2010-02-01

316

X-ray fluorescence computed tomography (XFCT) imaging of gold nanoparticle-loaded objects using 110 kVp x-rays.  

PubMed

A conventional x-ray fluorescence computed tomography (XFCT) technique requires monochromatic synchrotron x-rays to simultaneously determine the spatial distribution and concentration of various elements such as metals in a sample. However, the synchrotron-based XFCT technique appears to be unsuitable for in vivo imaging under a typical laboratory setting. In this study we demonstrated, for the first time to our knowledge, the possibility of performing XFCT imaging of a small animal-sized object containing gold nanoparticles (GNPs) at relatively low concentrations using polychromatic diagnostic energy range x-rays. Specifically, we created a phantom made of polymethyl methacrylate plastic containing two cylindrical columns filled with saline solution at 1 and 2 wt% GNPs, respectively, mimicking tumors/organs within a small animal. XFCT scanning of the phantom was then performed using microfocus 110 kVp x-ray beam and cadmium telluride (CdTe) x-ray detector under a pencil beam geometry after proper filtering of the x-ray beam and collimation of the detector. The reconstructed images clearly identified the locations of the two GNP-filled columns with different contrast levels directly proportional to gold concentration levels. On the other hand, the current pencil-beam implementation of XFCT is not yet practical for routine in vivo imaging tasks with GNPs, especially in terms of scanning time. Nevertheless, with the use of multiple detectors and a limited number of projections, it may still be used to image some objects smaller than the current phantom size. The current investigation suggests several modification strategies of the current XFCT setup, such as the adoption of the quasi-monochromatic cone/fan x-ray beam and XFCT-specific spatial filters or pinhole detector collimators, in order to establish the ultimate feasibility of a bench-top XFCT system for GNP-based preclinical molecular imaging applications. PMID:20071757

Cheong, Seong-Kyun; Jones, Bernard L; Siddiqi, Arsalan K; Liu, Fang; Manohar, Nivedh; Cho, Sang Hyun

2010-02-01

317

Depth profiles of Al impurities implanted in Si wafers determined by means of the high-resolution grazing emission X-ray fluorescence technique  

NASA Astrophysics Data System (ADS)

The synchrotron radiation based high-resolution grazing emission X-ray fluorescence (GEXRF) technique was used to extract the distribution of Al ions implanted with a dose of 10 16 atoms/cm 2 in Si wafers with energies ranging between 1 and 100 keV. The depth distributions of the implanted ions were deduced from the measured angular profiles of the Al-K ? X-ray fluorescence line with nanometer-scale precision. The experimental results were compared to theoretical predictions of the depth distributions resulting from ion implantation. A good agreement between experiment and theory was found which proved that the presented high-resolution grazing emission X-ray fluorescence technique is well suited to perform depth profiling measurements of impurities located within the extinction depth, provided the overall shape of the distribution can be assumed a priori.

Kayser, Y.; Bana?, D.; Cao, W.; Dousse, J.-Cl.; Hoszowska, J.; Jagodzi?ski, P.; Kav?i?, M.; Kubala-Kuku?, A.; Nowak, S.; Pajek, M.; Szlachetko, J.

2010-06-01

318

The first microbeam synchrotron X-ray fluorescence beamline at the Siam Photon Laboratory.  

PubMed

The first microbeam synchrotron X-ray fluorescence (µ-SXRF) beamline using continuous synchrotron radiation from Siam Photon Source has been constructed and commissioned as of August 2011. Utilizing an X-ray capillary half-lens allows synchrotron radiation from a 1.4?T bending magnet of the 1.2?GeV electron storage ring to be focused from a few millimeters-sized beam to a micrometer-sized beam. This beamline was originally designed for deep X-ray lithography (DXL) and was one of the first two operational beamlines at this facility. A modification has been carried out to the beamline in order to additionally enable µ-SXRF and synchrotron X-ray powder diffraction (SXPD). Modifications included the installation of a new chamber housing a Si(111) crystal to extract 8?keV synchrotron radiation from the white X-ray beam (for SXPD), a fixed aperture and three gate valves. Two end-stations incorporating optics and detectors for µ-SXRF and SXPD have then been installed immediately upstream of the DXL station, with the three techniques sharing available beam time. The µ-SXRF station utilizes a polycapillary half-lens for X-ray focusing. This optic focuses X-ray white beam from 5?mm × 2?mm (H × V) at the entrance of the lens down to a diameter of 100?µm FWHM measured at a sample position 22?mm (lens focal point) downstream of the lens exit. The end-station also incorporates an XYZ motorized sample holder with 25?mm travel per axis, a 5× ZEISS microscope objective with 5?mm × 5?mm field of view coupled to a CCD camera looking to the sample, and an AMPTEK single-element Si (PIN) solid-state detector for fluorescence detection. A graphic user interface data acquisition program using the LabVIEW platform has also been developed in-house to generate a series of single-column data which are compatible with available XRF data-processing software. Finally, to test the performance of the µ-SXRF beamline, an elemental surface profile has been obtained for a piece of ancient pottery from the Ban Chiang archaeological site, a UNESCO heritage site. It was found that the newly constructed µ-SXRF technique was able to clearly distinguish the distribution of different elements on the specimen. PMID:22713886

Tancharakorn, Somchai; Tanthanuch, Waraporn; Kamonsutthipaijit, Nuntaporn; Wongprachanukul, Narupon; Sophon, Methee; Chaichuay, Sarunyu; Uthaisar, Chunmanus; Yimnirun, Rattikorn

2012-07-01

319

X-ray laser related experiments and theory at Princeton  

SciTech Connect

This paper describes a new system for the development of an x-ray laser in the wavelength region from 5 nm to 1 nm utilizing a Powerful Sub-Picosecond Laser (PP-Laser) of expected peak power up to 0.5 TW in a 300 fs pulse. Soft x-ray spectra generated by the interaction of the PP-Laser beam with different targets are presented and compared to the spectra generated by a much less intense laser beam (20--30 GW). A theoretical model for the interaction of atoms with such a strong laser EM field is also briefly discussed. The development of additional amplifiers for the recombining soft x-ray laser and the design of a cavity are presented from the point of view of applications for x-ray microscopy and microlithography. This overview concludes with the presentation of recent results on the quenching of spontaneous emission radiation and its possible effect on the absolute intensity calibration of soft x-ray spectrometers. 26 refs., 18 figs.

Suckewer, S.

1989-04-01

320

Recent and future developments in low power total reflection X-ray fluorescence spectroscopy  

NASA Astrophysics Data System (ADS)

Today, energy-dispersive X-ray fluorescence (EDXRF) spectroscopy with low power X-ray tubes and thermoelectrically cooled detectors provide analytical performance which in the past was restricted to systems with kW power X-ray tubes and liquid nitrogen cooled Si(Li) detectors. Especially for low power TXRF spectrometers, the sensitivity could be improved by an order of one magnitude in the last 5 years. This progress was mainly based on improvements in quantum efficiency of all components and less on high power excitation sources. Recent developments caused further improvements in the analytical sensitivity as well as in the analytical performance. The introduction of a micro-focus X-ray tube increased the excitation power by a factor of 1.3. An additional improvement could be achieved by optimizing the detector window design. By optimizing the detector entrance geometry, the solid detection angle of a silicon drift detector (SDD) was increased by a factor of 1.8. In addition, the recent development of a new generation of silicon drift detectors increased the active detector area by a factor of three enhancing the peak to background ratio by a factor of two. Furthermore, the high-energy efficiency of this new detector type was significantly improved. As a result of all these improvements the detection limit for nickel could be decreased to a value of 1 pg.

Waldschlaeger, U.

2006-11-01

321

HIGH RESOLUTION X-RAY FLUORESCENCE MICRO-TOMOGRAPHY ON SINGLE SEDIMENT PARTICLES.  

SciTech Connect

This work focuses on the investigation of the distribution of contaminants in individual sediment particles from the New York/New Jersey Harbor. Knowledge of the spatial distribution of the contaminants within the particles is needed to enable (1) more sophisticated approaches to the understanding of the fate and transport of the contaminants in the environment and (2) more refined methods for cleaning the sediments. The size of the investigated particles ranges from 30-80 microns. Due to the low concentration of the elements of interest and the microscopic size of the environmental particles in these measurements, the small size and high intensity of the analyzing X-ray beam was critical. The high photon flux at the ESRF Microfocus beam line (ID13) was used as the basis for fluorescence tomography to investigate whether the inorganic compounds are taken upon the surface organic coating or whether they are distributed through the volume of the grains being analyzed. The experiments were done using a 13 keV monochromatic beam of approximately 2 {micro}m in size having an intensity of 10{sup 10} ph/s, allowing absolute detection limits on the 0.04-1 fg level for Ti, Cr, Mn, Fe, Ni, and Zn.

VINCZE,L.; VEKEMANS,B.; SZALOKI,I.; JANSSENS,K.; VAN GRIEKEN,R.; FENG,H.; JONES,K.W.; ADAMS,F.

2002-07-29

322

Iontophoresis: mechanism of action studied by potentiometry and x-ray fluorescence  

SciTech Connect

Physiotherapists often apply electrotherapeutic treatments to the knees with sponges impregnated with potassium iodide (KI). To study the fate of iodine applied in this way, the amount of iodide (I-) that penetrates the skin was determined using an iodide-selective electrode. The I- uptake was shown to take place only when galvanic current was applied. Iontophoresis did not result in superficial migration of the applied ions on the skin from one pole to the other, but led to penetration into the skin. The hyperemia, which occurs at the zone of application during iontophoresis, did not affect the uptake of subsequent treatments. Only very slight differences in uptake were observed for each patient with sequential application, whereas the interindividual differences were more pronounced. Combined evidence from all experiments suggested that about 10% of the applied KI had penetrated the skin. X-ray fluorescence scans of the volunteers' thyroid gland, before and after a series of 10 iontophoretic treatments, to establish whether I- was taken up by the thyroid, showed that the average iodine content of the gland was increased by more than 30%.

Puttemans, F.J.; Massart, D.L.; Gilles, F.; Lievens, P.C.; Jonckeer, M.H.

1982-04-01

323

Determination of mercury by total-reflection X-ray fluorescence using amalgamation with gold  

NASA Astrophysics Data System (ADS)

Analysis by total-reflection X-ray fluorescence (TXRF) is unsuitable for determining mercury concentrations because the usual sample preparation produces evaporation and loss of this element as a consequence of its high vapour pressure and low boiling point. A method that has been developed to achieve this determination involves forming an amalgam while a thin layer of silver (obtained by sputtering or evaporation) is in contact with an ionic solution of Hg; subsequently, a traditional TXRF analysis is performed. This was the first method reported in the literature to apply the TXRF technique for reliably determining mercury concentrations with high sensitivity. This work shows how a similar procedure may be employed to measure mercury concentrations. This second method involves forming an amalgam of gold using microlitre quantities of the solution to be analysed. As gold is a highly malleable material, it allows the production of very thin films, the weight of which is a few orders of magnitude higher than the mass of mercury present in the amalgam. The determination is performed in the usual way using the TXRF technique. The sensitivity of this method (? 5 ppm) is inferior to that of the former method, and data processing is quite difficult because the peaks for mercury and gold overlap, but the experiment is simple to execute and improved sensitivity is expected to be attained by forming the amalgam with larger volumes of sample and with a more responsive data processing scheme.

Bennun, L.; Gomez, J.

1997-07-01

324

Coprecipitative Preconcentration and X-Ray Fluorescence Determination of Rare Earths Based On Characteristic K-Radiation  

Microsoft Academic Search

This paper describes a method for the determination of rare earths at ppb level by coprecipitative preconcentration using iron (III) hydroxide as collector. the precipitates are collected by vacuum filtration onto filter paper containing ethyl cellulose powder. After drying the residue was powdered and pressed into pellets for quantitation by energy dispersive x-ray fluorescence (EDXRF) via their characteristic K-x ray

V. Bhagavathy; P. S. T. Sai; T. Prasada Rao; A. D. Damodaran

1989-01-01

325

Design of a pulsed x-ray system for fluorescent lifetime measurements with a timing accuracy of 109 ps.  

National Technical Information Service (NTIS)

We describe the design of a table-top pulsed x-ray system for measuring fluorescent lifetime and wavelength spectra of samples in both crystal and powdered form. The novel element of the system is a light-excited x-ray tube with a tungsten anode at +30 kV...

S. E. Derenzo W. W. Moses S. C. Blankespoor M. Ito K. Oba

1992-01-01

326

Phosphatization of basaltic rocks from Sal Island, Cape Verde Archipelago: A microtopochemical approach using synchrotron radiation X-ray fluorescence  

Microsoft Academic Search

The geochemical processes involved in phosphorous enrichment of volcanic rocks under shallow seawater are not yet fully understood. As a contribution to this problematic, a detailed chemical characterization of phosphatized basaltic hyaloclastites assigned at Sal Island, Cape Verde archipelago, was undertaken using synchrotron radiation X-ray fluorescence. The mineralogical constitution of the samples was characterized by combining X-ray diffraction and electron

M. O. Figueiredo; T. Pereira da Silva; J. P. Veiga; P. Chevallier

2003-01-01

327

Nondispersive soft x-ray fluorescence spectrometer for quantitative analysis of the major elements in rocks and minerals  

Microsoft Academic Search

A Si(Li) detector and a multichannel analyzer system were combined with ; a multiple anode soft x-ray generator and a high vacuum sample handling system to ; provide an x-ray fluorescence unit for quantitative analyses of the elements from ; oxygen to iron. A relatively rapid, accurate, and reproducible sample ; preparation technique and a method for sample matrix absorption

A. J. Hebert

1974-01-01

328

A new detection system with polycapillary conic collimator for high-localized analysis of X-ray fluorescence emission  

Microsoft Academic Search

In this paper, we present a new detection system conceived for the X-ray fluorescence (XRF) analysis of the radiation emitted by very small areas on the sample. The system is based on the use of a polycapillary conic collimator which captures the XRF emitted only from a local area of the sample independently on how extended is the X-ray excitation.

C. Fiorini; A. Longoni; A. Bjeoumikhov

2001-01-01

329

X-RAY SHADOWING EXPERIMENTS TOWARD INFRARED DARK CLOUDS  

SciTech Connect

We searched for X-ray shadowing toward two infrared dark clouds (IRDCs) using the MOS detectors on XMM-Newton to learn about the Galactic distribution of X-ray emitting plasma. IRDCs make ideal X-ray shadowing targets of 3/4 keV photons due to their high column densities, relatively large angular sizes, and known kinematic distances. Here we focus on two clouds near 30{sup 0} Galactic longitude at distances of 2 and 5 kpc from the Sun. We derive the foreground and background column densities of molecular and atomic gas in the direction of the clouds. We find that the 3/4 keV emission must be distributed throughout the Galactic disk. It is therefore linked to the structure of the cooler material of the interstellar medium and to the birth of stars.

Anderson, L. D.; Bania, T. M. [Department of Astronomy, 725 Commonwealth Ave., Boston University, Boston, MA 02215 (United States); Snowden, S. L. [NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States)

2010-10-01

330

X-Ray Shadowing Experiments Toward Infrared Dark Clouds  

NASA Technical Reports Server (NTRS)

We searched for X-ray shadowing toward two infrared dark clouds (IRDCs) using the MOS detectors on XMM-Newton to learn about the Galactic distribution of X-ray emitting plasma. IRDCs make ideal X-ray shadowing targets of 3/4 keY photons due to their high column densities, relatively large angular sizes, and known kinematic distances. Here we focus on two clouds near 30 deg Galactic longitude at distances of 2 and 5 kpc from the Sun. We derive the foreground and background column densities of molecular and atomic gas in the direction of the clouds. We find that the 3/4 ke V emission must be distributed throughout the Galactic disk. It is therefore linked to the structure of the cooler material of the ISM, and to the birth of stars.

Anderson, L. E.; Snowden, S.; Bania, T. M.

2009-01-01

331

In-Flight Performance of the High-Energy X-Ray Timing Experiment on the Rossi X-Ray Timing Explorer  

Microsoft Academic Search

The High Energy X-Ray Timing Experiment (HEXTE) is one of three scientific instruments aboard the Rossi X-Ray Timing Explorer (RXTE), which was launched on 1995 December 30. RXTE performs timing and spectral studies of bright X-ray sources to determine the physical parameters of these systems. The HEXTE consists of two independent clusters of detectors, each cluster containing four NaI(Tl)\\/CsI(Na) phoswich

R. E. Rothschild; P. R. Blanco; D. E. Gruber; W. A. Heindl; D. R. MacDonald; D. C. Marsden; M. R. Pelling; L. R. Wayne; P. L. Hink

1998-01-01

332

Feasibility study for the in vivo measurement of lead in bone using L-x-ray fluorescence  

SciTech Connect

Lead deposits in bone were detected by x-ray fluorescence using x-rays from either a /sup 125/I or a /sup 109/Cd source. Measurements were taken from tibia in intact human legs, post-mortem. On the basis of preliminary measurements, it was concluded that an exposure of one rad is adequate for determination of lead in bone. Both the advantages and the disadvantages of L-x-rays, used in the technique developed for this study, are compared with those of K-x-rays.

Wielopolski, L.; Slatkin, D.N.; Vartsky, D.; Ellis, K.J.; Cohn, S.H.

1980-01-01

333

The Development of High-Resolution Calorimetric X-Ray Detectors for Compton Scattering Experiments  

Microsoft Academic Search

Compton scattering is a means of probing electron momentum distributions and can be used to evaluate calculations of electron wavefunctions in solids. The need for improved resolution in Compton experiments performed with high energy x-rays has motivated the development of a high resolution spectrometer. Calorimetric x-ray detectors, produced at Goddard Space Flight Center for x-rays around 6 KeV, have been

Caroline Kilbourne Stahle

1992-01-01

334

Capillary electrophoresis micro X-ray fluorescence: a tool for benchtop elemental analysis.  

PubMed

A new tool was developed for separation and elemental detection by interfacing a simple capillary electrophoresis (CE) apparatus, constructed using a thin-walled fused-silica capillary, with a benchtop energy-dispersive micro X-ray fluorescence (MXRF) system. X-ray excitation and detection of the separated analytes was done using an EDAX Eagle II micro X-ray fluorescence system equipped with a polycapillary Rh target excitation source and a SiLi detector. It was demonstrated that this prototype system could be used for the separation and detection of species containing two different metals from one another, specifically Cu and Co. Free Co could also be separated from Co bound to cyanocobalamin (vitamin B-12). Two organic compounds were also separated from one another, a large biological protein, ferritin, from a small biological organic, cyanocobalamin. Preliminary average detection limits obtained on this system were on the order of 10(-)(4) M and compared favorably to those reported for the similar technique of CE-synchrotron XRF. CEMXRF allows for nondestructive, simultaneous, on-line, benchtop elemental analysis for chemical speciation applications. PMID:12720339

Miller, Thomasin C; Joseph, Martha R; Havrilla, George J; Lewis, Cris; Majidi, Vahid

2003-05-01

335

A new fundamental parameter based calibration procedure for micro X-ray fluorescence spectrometers  

NASA Astrophysics Data System (ADS)

Fundamental parameter based quantification of X-ray fluorescence (XRF) measurement data requires an accurate knowledge of the spectrometer parameters, including the spectral distribution of the excitation radiation. In case of micro-XRF where a polycapillary optic is utilized in the excitation channel this distribution is changed due to the transmission properties of the lens. A new calibration procedure, based on fluorescence data of thin standard samples, was developed to determine the excitation spectrum, i.e., the product of the X-ray tube spectrum and the transmission of the used X-ray optic of a micro-XRF setup. The calibration result was validated by the quantitative analyses of certified multi-element reference standards and shows uncertainties in the order of 2% for main components, 10% for minor elements and 25% for trace elements. The influence of secondary order effects like Coster-Kronig transitions and cascade effects is analyzed and the accuracy of fundamental parameters in common databases is discussed.

Wolff, Timo; Malzer, Wolfgang; Mantouvalou, Ioanna; Hahn, Oliver; Kanngießer, Birgit

2011-02-01

336

Scanning protein analysis of electrofocusing gels using X-ray fluorescence.  

PubMed

Recently, "metallomics," in addition to genomics and proteomics, has become a focus as a novel approach to identify sensitive fluctuations in homeostasis that accompany metabolic processes, such as stress responses, differentiation, and proliferation. Cellular elements and associated protein behavior provide important clues for understanding cellular and disease mechanism(s). It is important to develop a system for measuring the native status of the protein. In this study, we developed an original freeze-dried electrofocusing native gel over polyimide film (native-gel film) for scanning protein analysis using synchrotron radiation excited X-ray fluorescence (SPAX). To our knowledge, this is the first report detailing the successful mapping of metal-associated proteins of electrofocusing gels using X-ray fluorescence. SPAX can provide detection sensitivity equivalent to that of LA-ICP-MS. In addition to this increased sensitivity, SPAX has the potential to be combined with other X-ray spectroscopies. Our system is useful for further applications in proteomics investigating cellular element-associated protein behaviors and disease mechanisms. PMID:23576194

Matsuyama, Satoshi; Matsunaga, Akihiro; Sakamoto, Shinichi; Iida, Yutaka; Suzuki, Yoshinari; Ishizaka, Yukihito; Yamauchi, Kazuto; Ishikawa, Tetsuya; Shimura, Mari

2013-05-01

337

A new method for x-ray fluorescence analysis of contaminated material. Final Report  

SciTech Connect

Niton has successfully completed the objectives of the Phase II program to build a hand-held, x-ray fluorescent analyzer optimized for DOE decontamination and decommissioning activities in the field. A two-pound x-ray fluorescence analyzer was developed that contains 3 radioactive sources, emitting 3 widely spaced monochromatic x-rays, to give the lowest detection limits for the full range of toxic elements, from chromium to plutonium. A rapid, fundamental- parameters algorithm was developed that yields quantitative results in less than 1 second. High-resolution silicon drift detectors and silicon PIN diodes give excellent efficiency and speed. These results from Phase II have been introduced into the XL 300, 700 and 800 commercial products series. More than 800 of these instruments, yielding revenues of more than $20 million dollars, have been sold since the first 3-source instrument was introduced in 1998. A direct consequence of the Phase II funding has been the growth of Niton from 20 people to its present size of 60.

Grodzins, Lee; Niland, John

2002-05-23

338

Determination of minor and trace elements in kidney stones by x-ray fluorescence analysis  

NASA Astrophysics Data System (ADS)

The determination of accurate material composition of a kidney stone is crucial for understanding the formation of the kidney stone as well as for preventive therapeutic strategies. Radiations probing instrumental activation analysis techniques are excellent tools for identification of involved materials present in the kidney stone. In particular, x-ray fluorescence (XRF) can be very useful for the determination of minor and trace materials in the kidney stone. The X-ray fluorescence measurements were performed at the Radiation Measurements and Spectroscopy Laboratory (RMSL) of department of nuclear engineering of Missouri University of Science and Technology and different kidney stones were acquired from the Mayo Clinic, Rochester, Minnesota. Presently, experimental studies in conjunction with analytical techniques were used to determine the exact composition of the kidney stone. A new type of experimental set-up was developed and utilized for XRF analysis of the kidney stone. The correlation of applied radiation source intensity, emission of X-ray spectrum from involving elements and absorption coefficient characteristics were analyzed. To verify the experimental results with analytical calculation, several sets of kidney stones were analyzed using XRF technique. The elements which were identified from this techniques are Silver (Ag), Arsenic (As), Bromine (Br), Chromium (Cr), Copper (Cu), Gallium (Ga), Germanium (Ge), Molybdenum (Mo), Niobium (Nb), Rubidium (Rb), Selenium (Se), Strontium (Sr), Yttrium (Y), Zirconium (Zr). This paper presents a new approach for exact detection of accurate material composition of kidney stone materials using XRF instrumental activation analysis technique.

Srivastava, Anjali; Heisinger, Brianne J.; Sinha, Vaibhav; Lee, Hyong-Koo; Liu, Xin; Qu, Mingliang; Duan, Xinhui; Leng, Shuai; McCollough, Cynthia H.

2014-03-01

339

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

NASA Technical Reports Server (NTRS)

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

Boldt, E. A.

1973-01-01

340

Enhanced coherence x-ray laser experiments and simulations  

Microsoft Academic Search

Bright, spatially coherent x-ray lasers (XRLs) have applications in areas such as holography, interferometric imaging, and non-linear optics. Nominally, we can improve XRL coherence by either increasing the length or by reducing the aperture. The length can be increased by coupling multiple stages of XRLs or by using multilayer optics, but the effective gain length of an XRL is limited

Alan S. Wan; Stephen B. Libby; Juan C. Moreno

1994-01-01

341

High-resolution X-ray imaging in fast ignition experiment using Gekko and LFEX lasers  

NASA Astrophysics Data System (ADS)

We improved diagnostic instruments to measure X-ray images in a hard X-ray harsh environment and succeeded in obtaining clear images with X-ray framing camera and X-ray streak camera in fast ignition experiment conducted in 2011 (FG-02 Experimental Campaign). We found that high-energy X-ray signals could be used as an indicator of the LFEX laser injection time relative to the imploded core. The LFEX laser injection time was estimated with better than 10 ps accuracy. Time-resolved 2D X-ray images suggested that shapes and motions of imploded core plasmas were improved by changing the configuration of the implosion lasers.

Koga, M.; Ishii, Y.; Sogo, T.; Shigemori, K.; Shiraga, H.; Fujioka, S.; Azechi, H.

2013-11-01

342

Metallic out-diffusion quantification in polymers by x-ray fluorescence  

NASA Astrophysics Data System (ADS)

X-ray fluorescence is a technique that has sensitivity within parts-per-million elemental content level, which is sufficient to probe trace materials. In this study two X-ray sources were used, copper and silver radiation, to detect metallic additives used to modify the properties of polymers. The technique requires minimal to no sample preparation and is non-destructive. In the present case trace materials of heavy metals are identified in two types of polymers, polypropylene and polycarbonate, before and after being exposed to energy intake sufficient to detach the metals directly or to promote the formation of hydroperoxide; this last one indirectly produces detachment through re-arrangement of the polymeric matrix. Quantification of heavy metal detachment and out-diffusion is relevant due to possible adverse effects that may arise when such elements make contact with consumables.

Bencomo, Miguel; Castro-Colin, Miguel

2009-10-01

343

Chemical effect on the K shell x-ray fluorescence parameters of some Ce compounds.  

PubMed

Chemical effects on the K?/K? x-ray intensity ratios, fluorescence yields wK and vacancy transfer probabilities ?KL for some Ce compounds were investigated. In this study, the samples were excited by 59.54 keV ?-rays from a 5Ci (241)Am annular radioactive source. K x-rays emitted by samples were counted by an HPGe detector with a resolution of 182 eV at 5.9 keV. The experimental values were compared with the theoretical and other experimental values. The aim of these measurements was to characterize the dependence of the line position and line width with the chemical environment changes. PMID:23500654

Tur?ucu, A; Demir, D

2013-07-01

344

Fundamental parameter based quantification algorithm for confocal nano-X-ray fluorescence analysis  

NASA Astrophysics Data System (ADS)

A new method for the quantification of X-ray fluorescence (XRF) was derived based on the fundamental parameter method (FPM). The FPM equations were adapted to accommodate the special case of confocal nano-XRF, i.e. X-ray nano-beam excitation coupled with confocal detection, taking into account the special characteristics of the detector channel polycapillary. A thorough error estimation algorithm based on the Monte Carlo method was applied, producing a detailed analysis of the uncertainties of the quantification results. The new FPM algorithm was applied on confocal nano-XRF data obtained from cometary dust returned by NASA's Stardust mission, recorded at beamline ID13 of the European Synchrotron Radiation Facility.

Schoonjans, Tom; Silversmit, Geert; Vekemans, Bart; Schmitz, Sylvia; Burghammer, Manfred; Riekel, Christian; Brenker, Frank E.; Vincze, Laszlo

2012-01-01

345

Trace element determination of mercury by total-reflection X-ray fluorescence  

NASA Astrophysics Data System (ADS)

A rapid and simple method is presented for the determination of trace amounts of ionic mercury in solutions by total-reflection X-ray fluorescence. The method relies on the formation of a mercury amalgam on a 50 nm thick silver coating deposited on a specular-surface quartz reflector. Quantification of Hg in dilute HNO 3 solutions is achieved, with a straight calibration line in the concentration range 50-350 ng ml -1. With excitation by a molybdenum anode X-ray tube at 40 kV and 20 mA, the limit of detection achieved for a 2 cm 3 specimen with 1000 s counting time is 15 ng ml -1.

Greaves, E. D.; Alfonso Sosa, J.; Sajo-Bohus, L.; Alvarez, M.; Wobrauschek, P.; Streli, Ch.

1997-07-01

346

Development of High-Speed Fluorescent X-Ray Micro-Computed Tomography  

SciTech Connect

A high-speed fluorescent x-ray CT (FXCT) system using monochromatic synchrotron x rays was developed to detect very low concentration of medium-Z elements for biomedical use. The system is equipped two types of high purity germanium detectors, and fast electronics and software. Preliminary images of a 10mm diameter plastic phantom containing channels field with iodine solutions of different concentrations showed a minimum detection level of 0.002 mg I/ml at an in-plane spatial resolution of 100{mu}m. Furthermore, the acquisition time was reduced about 1/2 comparing to previous system. The results indicate that FXCT is a highly sensitive imaging modality capable of detecting very low concentration of iodine, and that the method has potential in biomedical applications.

Takeda, T.; Tsuchiya, Y.; Wu, J.; Lwin, Thet-Thet; Yashiro, T.; Matsumura, K.; Itai, Y. [Institute of Clinical Medicine, University of Tsukuba, Tsukuba-shi, Ibaraki 305-8575 (Japan); Kuroe, T.; Zeniya, T.; Yuasa, T.; Akatsuka, T. [Faculty of Engineering, Yamagata University, Yonezawa-shi, Yamagata 992-8510 (Japan); Hyodo, K. [Institute of Materials Structure Science, High Energy Acceleration Research Organization (Japan); Dilmanian, F.A. [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2004-05-12

347

Characterization of a polycapillary focusing X-ray lens for application in spatially resolved EXAFS experiments  

NASA Astrophysics Data System (ADS)

A dispersive extended-X-ray-absorption-fine-structure (EXAFS) spectrometer based on a polycapillary focusing X-ray lens (PFXRL), a position-sensitive proportional counter and a rotating anode X-ray source is designed. When the working voltage and current of a Mo rotating anode X-ray generator are 25 kV and 100 mA, respectively, it takes 6 h to obtain the EXAFS spectrum of the Cu film. The experiments show that a dispersive EXAFS spectrometer based on a PFXRL can be applied in spatially resolved EXAFS analysis.

Sun, Tianxi; Liu, Zhiguo; Ding, Xunliang

2007-05-01

348

A step toward standardization: development of accurate measurements of X-ray absorption and fluorescence.  

PubMed

This paper explains how to take the counting precision available for XAFS (X-ray absorption fine structure) and attenuation measurements, of perhaps one part in 10(6) in special cases, to produce a local variance below 0.01% and an accuracy of attenuation of the order 0.01%, with an XAFS accuracy at a similar level leading to the determination of dynamical bond lengths to an accuracy similar to that obtained by standard and experienced crystallographic measurements. This includes the necessary corrections for the detector response to be linear, including a correction for dark current and air-path energy dependencies; a proper interpretation of the range of sample thicknesses for absorption experiments; developments of methods to measure and correct for harmonic contamination, especially at lower energies without mirrors; the significance of correcting for the actual bandwidth of the beam on target after monochromation, especially for the portability of results and edge structure from one beamline to another; definitions of precision, accuracy and XAFS accuracy suitable for theoretical model analysis; the role of additional and alternative high-accuracy procedures; and discusses some principles regarding data formats for XAFS and for the deposition of data sets with manuscripts or to a database. Increasingly, the insight of X-ray absorption and the standard of accuracy needed requires data with high intrinsic precision and therefore with allowance for a range of small but significant systematic effects. This is always crucial for absolute measurements of absorption, and is of equal importance but traditionally difficult for (usually relative) measurements of fluorescence XAFS or even absorption XAFS. Robust error analysis is crucial so that the significance of conclusions can be tested within the uncertainties of the measurements. Errors should not just include precision uncertainty but should attempt to include estimation of the most significant systematic error contributions to the results. This is essential if the results are to be subject to deposition in a central accessible reference database; it is also crucial for specifying a standard data format for portability and ease of use by depositors and users. In particular this will allow development of theoretical formulations to better serve the world-wide XAFS community, and a higher and more easily comparable standard of manuscripts. PMID:23093742

Chantler, Christopher T; Barnea, Zwi; Tran, Chanh Q; Rae, Nicholas A; de Jonge, Martin D

2012-11-01

349

L-shell x-ray fluorescence computed tomography (XFCT) imaging of Cisplatin.  

PubMed

X-ray fluorescence computed tomography (XFCT) imaging has been focused on the detection of K-shell x-rays. The potential utility of L-shell x-ray XFCT is, however, not well studied. Here we report the first Monte Carlo (MC) simulation of preclinical L-shell XFCT imaging of Cisplatin. We built MC models for both L- and K-shell XFCT with different excitation energies (15 and 30 keV for L-shell and 80 keV for K-shell XFCT). Two small-animal sized imaging phantoms of 2 and 4 cm diameter containing a series of objects of 0.6 to 2.7 mm in diameter at 0.7 to 16 mm depths with 10 to 250 µg mL(-1) concentrations of Pt are used in the study. Transmitted and scattered x-rays were collected with photon-integrating transmission detector and photon-counting detector arc, respectively. Collected data were rearranged into XFCT and transmission CT sinograms for image reconstruction. XFCT images were reconstructed with filtered back-projection and with iterative maximum-likelihood expectation maximization without and with attenuation correction. While K-shell XFCT was capable of providing an accurate measurement of Cisplatin concentration, its sensitivity was 4.4 and 3.0 times lower than that of L-shell XFCT with 15 keV excitation beam for the 2 cm and 4 cm diameter phantom, respectively. With the inclusion of excitation and fluorescence beam attenuation correction, we found that L-shell XFCT was capable of providing fairly accurate information of Cisplatin concentration distribution. With a dose of 29 and 58 mGy, clinically relevant Cisplatin Pt concentrations of 10 µg mg(-1) could be imaged with L-shell XFCT inside a 2 cm and 4 cm diameter object, respectively. PMID:24334507

Bazalova, Magdalena; Ahmad, Moiz; Pratx, Guillem; Xing, Lei

2014-01-01

350

Experimental demonstration of novel imaging geometries for x-ray fluorescence computed tomography  

PubMed Central

Purpose: X-ray fluorescence computed tomography (XFCT) is an emerging imaging modality that maps the three-dimensional distribution of elements, generally metals, in ex vivo specimens and potentially in living animals and humans. At present, it is generally performed at synchrotrons, taking advantage of the high flux of monochromatic x rays, but recent work has demonstrated the feasibility of using laboratory-based x-ray tube sources. In this paper, the authors report the development and experimental implementation of two novel imaging geometries for mapping of trace metals in biological samples with ?50–500 ?m spatial resolution. Methods: One of the new imaging approaches involves illuminating and scanning a single slice of the object and imaging each slice's x-ray fluorescent emissions using a position-sensitive detector and a pinhole collimator. The other involves illuminating a single line through the object and imaging the emissions using a position-sensitive detector and a slit collimator. They have implemented both of these using synchrotron radiation at the Advanced Photon Source. Results: The authors show that it is possible to achieve 250 eV energy resolution using an electron multiplying CCD operating in a quasiphoton-counting mode. Doing so allowed them to generate elemental images using both of the novel geometries for imaging of phantoms and, for the second geometry, an osmium-stained zebrafish. Conclusions: The authors have demonstrated the feasibility of these two novel approaches to XFCT imaging. While they use synchrotron radiation in this demonstration, the geometries could readily be translated to laboratory systems based on tube sources.

Fu, Geng; Meng, Ling-Jian; Eng, Peter; Newville, Matt; Vargas, Phillip; Riviere, Patrick La

2013-01-01

351

X-ray bandwidth: Determination by on-edge absorption and effect on various absorption experiments  

SciTech Connect

Knowledge of the monochromaticity of an x-ray source is increasingly important in fundamental experiments and critical applications. The bandwidth of an x-ray beam, selected from a synchrotron radiation spectrum for example, ultimately defines the limiting resolution of the synchrotron source. The development of x-ray technology through the use of characteristic line sources of fixed line shape has impaired the development of understanding of this parameter. The bandwidth is particularly relevant with the modern trend towards the use of synchrotron sources in conjunction with monochromating devices, where the monochromaticity of the x-ray beam is not known a priori. The ability to control the bandwidth of the beam can lead to significant new experiments. We have observed the effect of the x-ray bandwidth on precise but relatively scaled measurements of the mass attenuation coefficient of molybdenum made on the absorption edge. We derive an expression describing the effect of the x-ray bandwidth on these measurements and invert this to determine the bandwidth of a highly monochromatized 20-keV synchrotron x-ray beam to be 1.57 eV{+-}0.03 eV. The technique presented here determines the bandwidth, a parameter critically dependent on the x-ray optical elements in the beam, in such a manner as to require no knowledge of these elements. We demonstrate that the x-ray bandwidth has significant effects upon measured edge energies, mass attenuation coefficients, x-ray anomalous-fine structure and x-ray absorption near-edge structure (XANES). In particular, the observed x-ray bandwidth necessitates a correction of up to 1.4% in the measurement of the mass attenuation coefficient of molybdenum on the absorption edge and is shown to shift the observed absorption-edge energy location by up to 0.5 eV.

Jonge, Martin D. de; Barnea, Zwi; Tran, Chanh Q.; Chantler, Christopher T. [School of Physics, University of Melbourne (Australia)

2004-02-01

352

Mutual influence of elements in x-ray fluorescence analysis of thin bilayer Ni/Ge-systems  

NASA Astrophysics Data System (ADS)

A new approach to the determination of the layer thickness in x-ray fluorescence analysis of bilayer Ni/Ge-systems was proposed. The approach was based on accounting for the degree of attenuation in the upper layer of both the primary x-ray tube radiation and the analytical line of the lower-layer element and the fluorescence intensity amplification of the upper layer by radiation from lower-layer atoms.

Mashin, N. I.; Razuvaev, A. G.; Chernyaeva, E. A.; Tumanova, A. N.; Ershov, A. A.

2013-03-01

353

Confocal X-ray Fluorescence (XRF) Microscopy: A New Technique for the Nondestructive Compositional Depth Profiling of Paintings  

Microsoft Academic Search

A confocal x-ray fluorescence microscope was built at the Cornell High Energy Synchrotron Source (CHESS) to determine the composition of buried paint layers that range from 10-80 µm thick in paintings. The microscope consists of a borosilicate monocapillary optic to focus the incident beam and a borosilicate polycapillary lens to collect the fluorescent x-rays. The overlap of the two focal

Arthur R. Woll; Donald H. Bilderback; Sol Gruner; Ning Gao; Rong Huang; Christina Bisulca

354

Fast application of X-ray fluorescence spectrometry aboard ship: how good is the new portable Spectro Xepos analyser?  

Microsoft Academic Search

A technique for onsite application of X-ray fluorescence (XRF) spectrometry to samples from sediment cores aboard a research vessel was developed and tested. The method is sufficiently simple, precise, and fast to be used routinely for high-resolution analyses of depth profiles as well as surface samples. Analyses were performed with the compact high-performance energy-dispersive polarisation X-ray fluorescence (EDPXRF) analyser Spectro

Katharina Wien; Dirk Wissmann; Martin Kölling; Horst D. Schulz

2005-01-01

355

Study of archaeological ceramics by total-reflection X-ray fluorescence spectrometry: Semi-quantitative approach  

Microsoft Academic Search

Total-reflection X-ray fluorescence spectrometry has been compared with Instrumental Neutron Activation Analysis in order to test its potential application to the study of archaeological ceramics in the archaeometric field. Two direct solid non-chemical sample preparation procedures have been checked: solid sedimentation and solid chemical homogenization. For sedimentation procedure, total-reflection X-ray fluorescence allows the analysis of the elemental composition with respect

R. Fernįndez-Ruiz; M. Garcķa-Heras

2007-01-01

356

In situ x-ray fluorescence and californium-252 neutron activation analysis for marine and terrestrial mineral exploration  

Microsoft Academic Search

Instrumentation has been designed for in situ analysis of marine and terrestrial minerals using the techniques of x-ray fluorescence and neutron activation analysis. The energy-dispersive x-ray fluorescence analyzer allows more than 20 elements to be quantitatively measured at the 10 ppM level in water depths to 300 m. The analyzer consists of a solid cryogen-cooled Si(Li) detector, a 50 mCi

Wogman

1976-01-01

357

Construction and calibration of a low cost X-ray Fluorescence apparatus for compositional analysis of materials  

Microsoft Academic Search

X-Ray Fluorescence (XRF) is a useful tool for determining elemental composition of materials. This work involves constructing a fluorescence apparatus using an Eclipse III Tube 30 keV Source with a current of 0-100 muA and a XR-100CR X-ray detector with DP4 Preamplifier and MCA. The apparatus was constructed from independent components, interfaced for automated data acquisition, calibrated and used to

Sterling Beeson; David Bixler; Charles Allen; Toni Sauncy

2009-01-01

358

An x-ray fluorescence imaging system for gold nanoparticle detection.  

PubMed

Gold nanoparticles (GNPs) may be used as a contrast agent to identify tumour location and can be modified to target and image specific tumour biological parameters. There are currently no imaging systems in the literature that have sufficient sensitivity to GNP concentration and distribution measurement at sufficient tissue depth for use in in vivo and in vitro studies. We have demonstrated that high detecting sensitivity of GNPs can be achieved using x-ray fluorescence; furthermore this technique enables greater depth imaging in comparison to optical modalities. Two x-ray fluorescence systems were developed and used to image a range of GNP imaging phantoms. The first system consisted of a 10 mm(2) silicon drift detector coupled to a slightly focusing polycapillary optic which allowed 2D energy resolved imaging in step and scan mode. The system has sensitivity to GNP concentrations as low as 1 ppm. GNP concentrations different by a factor of 5 could be resolved, offering potential to distinguish tumour from non-tumour. The second system was designed to avoid slow step and scan image acquisition; the feasibility of excitation of the whole specimen with a wide beam and detection of the fluorescent x-rays with a pixellated controlled drift energy resolving detector without scanning was investigated. A parallel polycapillary optic coupled to the detector was successfully used to ascertain the position where fluorescence was emitted. The tissue penetration of the technique was demonstrated to be sufficient for near-surface small-animal studies, and for imaging 3D in vitro cellular constructs. Previous work demonstrates strong potential for both imaging systems to form quantitative images of GNP concentration. PMID:24145214

Ricketts, K; Guazzoni, C; Castoldi, A; Gibson, A P; Royle, G J

2013-11-01

359

High energy x-ray diffraction\\/x-ray fluorescence spectroscopy for high-throughput analysis of composition spread thin films  

Microsoft Academic Search

High-throughput crystallography is an important tool in materials research, particularly for the rapid assessment of structure-property relationships. We present a technique for simultaneous acquisition of diffraction images and fluorescence spectra on a continuous composition spread thin film using a 60 keV x-ray source. Subsequent noninteractive data processing provides maps of the diffraction profiles, thin film fiber texture, and composition. Even

John M. Gregoire; Darren Dale; Alexander Kazimirov; Francis J. DiSalvo; R. Bruce van Dover

2009-01-01

360

A Search for Transient X-Ray Sources with ARIEL-5 Experiment-C  

NASA Astrophysics Data System (ADS)

The Ariel 5 MSSL Experiment C data bank has been systematically searched for transient and variable X-ray sources. Nineteen objects (many of which cannot be identified with previously known X-ray sources) have been detected. Spectra and other properties of these transients are reported.

Chiappetti, L.; Bell-Burnell, S. J.

1983-02-01

361

Sodium-neon resonant photoexcitation soft x-ray laser experiments on Saturn  

SciTech Connect

This paper summarizes progress made at Sandia Laboratories on x-ray lasers. Experiments have demonstrated two main requirements necessary for constructing a radiation pumped soft x-ray laser: (1) a source of sufficient intensity to produce high grain and (2) creation of a significant population of neon ions close to the pump. (FSD) 11 figs.

Porter, J.; Spielman, R.; Matzen, K.; McGuire, G.; Hussey, T.

1990-01-01

362

Airborne Particulate Matter (PM) filter analysis and modeling by Total reflection X-Ray Fluorescence (TXRF) and X-Ray Standing Wave (XSW)  

PubMed Central

This work is presented as an improvement of a recently introduced method for airborne particulate matter (PM) filter analysis [1]. X-ray Standing Wave (XSW) and Total reflection X-Ray Fluorescence (TXRF) were performed with a new dedicated laboratory instrumentation. The main advantage of performing both XSW and TXRF, is the possibility to distinguish the nature of the sample: if it is a small droplet dry residue, a thin film like or a bulk sample; and to select the angle of total reflection to make TXRF measurements. Finally, the possibility to switch the X-ray source allows to measure with more accuracy lighter and heavier elements (with a a change in X-ray anode, for example from Mo to Cu). The aim of the present study is to lay the theoretical foundation of the new proposed method for airborne PM filters quantitative analysis improving the accuracy and efficiency of quantification by means of an external standard. The theoretical model presented and discussed demonstrated that airborne PM filters can be considered as thin layers. A set of reference samples is prepared in laboratory and used to obtain a calibration curve. Our results demonstrate that the proposed method for quantitative analysis of air PM filters is affordable and reliable without the necessity to digest filters to obtain quantitative chemical analysis, and that the use of XRW improve the accuracy of TXRF analysis.

Borgese, L.; Salmistraro, M.; Gianoncelli, A; Zacco, A.; Lucchini, R.; Zimmerman, N.; Pisani, L.; Siviero, G.; Depero, L. E.; Bontempi, E.

2011-01-01

363

Ultrafast X-ray Experiments Using Terahertz Excitation  

Microsoft Academic Search

With the availability of the first generation of X-ray free electron lasers, pump-probe measurements with femtosecond resolution and high brilliance are now possible. For condensed matter systems, a wealth of modes in the mid-infrared (MIR) and terahertz (THz) regime determine the physics such that targeted excitation with ultrashort pulses at long wavelength becomes an important tool. We will briefly discuss

Matthias C. Hoffmann; Joshua J. Turner

2012-01-01

364

Hyper-filter-fluorescer spectrometer for x-rays above 120 keV  

DOEpatents

An apparatus utilizing filter-fluorescer combinations is provided to measure short bursts of high fluence x-rays above 120 keV energy, where there are no practical absorption edges available for conventional filter-fluorescer techniques. The absorption edge of the prefilter is chosen to be less than that of the fluorescer, i.e., E.sub.PRF E.sub.F. In this way, the response function is virtually zero between E.sub.PRF and E.sub.F and well defined and enhanced in an energy band of less than 1000 keV above the 120 keV energy.

Wang, Ching L. (Livermore, CA)

1983-01-01

365

Total reflection X-ray fluorescence and archaeometry: Application in the Argentinean cultural heritage  

NASA Astrophysics Data System (ADS)

Archaeometry is an interdisciplinary research area involved in the development and use of scientific methods in order to answer questions concerned with the human history. In this way the knowledge of archaeological objects through advanced chemical and physical analyses permits a better preservation and conservation of the cultural heritage and also reveals materials and technologies used in the past. In this sense, analytical techniques play an important role in order to provide chemical information about cultural objects. Considering the non destructive characteristic of this study, analytical techniques must be adequate in order to prevent any alteration or damage and in addition to allow the conservation of their integrity. Taking into account the irreplaceable character of the archaeological and artistic materials considered in this study, analytical techniques must be adequate in order to prevent any alteration or damage and in addition to allow the conservation of their integrity. Total Reflection X-ray Fluorescence Spectrometry as a geometric variant of conventional X-ray fluorescence is a proved microanalytical technique considering the small amount of sample required for the analysis. A few micrograms are enough in order to reveal valuable information about elemental composition and in this context it is highly recommended for artwork studies. In this paper a case study is presented in which Total Reflection X-Ray Fluorescence Spectrometry has been successfully employed in the archaeometry field. Examples from Argentinean cultural heritage sites related with the determination of pigments in paintings on canvas and in rock sites as well as in underwater archaeology research are shown.

Vįzquez, Cristina; Albornoz, Ana; Hajduk, Adam; Elkin, Dolores; Custo, Graciela; Obrustky, Alba

2008-12-01

366

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

367

Lead Concentration in Human Bone Measured via X-Ray Fluorescence  

NASA Astrophysics Data System (ADS)

Lead is a naturally occurring element found throughout our environment. Once ingested, lead can present itself in our blood and bone. Lead has been known to cause health problems for quite some time. The standard way to diagnose lead poisoning has been through serum blood levels. The advantage to bone lead measurements is that it gives information about long term exposure, since lead remains in the bone for a longer period of time than in the blood. The technique of x-ray fluorescence can be used to non-invasively measure bone lead levels in humans. By using a high energy photon one can excite a lead atom. When the atom de-excites it emits x-rays. These emitted x-rays are of specific energies linked to lead. Using a HPGe scintillator detector we can look for these energies to determine the presence and concentration of lead in bone. By comparing the coherent peak amplitude with the lead peak amplitudes we can determine the lead levels in parts per million (ppm) of bone mass. Our goal is to collect data from a wide variety of patient volunteers to get a common standard of the Ogden Valley. This standard can be used for comparison for possible future measurements of individuals with suspected lead poisoning. Preliminary results will be discussed in this presentation.

Smith, Ryan; Arnold, M.

2004-10-01

368

Phase-resolved x-ray ferromagnetic resonance measurements in fluorescence yield  

SciTech Connect

Phase-resolved x-ray ferromagnetic resonance (XFMR) has been measured in fluorescence yield, extending the application of XFMR to opaque samples on opaque substrates. Magnetization dynamics were excited in a Co{sub 50}Fe{sub 50}(0.7)/Ni{sub 90}Fe{sub 10}(5) bilayer by means of a continuous wave microwave excitation, while x-ray magnetic circular dichroism (XMCD) spectra were measured stroboscopically at different points in the precession cycle. By tuning the x-ray energy to the L{sub 3} edges of Ni and Fe, the dependence of the real and imaginary components of the element specific magnetic susceptibility on the strength of an externally applied static bias field was determined. First results from measurements on a Co{sub 50}Fe{sub 50}(0.7)/Ni{sub 90}Fe{sub 10}(5)/Dy(1) sample confirm that enhanced damping results from the addition of the Dy cap.

Marcham, M. K.; Keatley, P. S.; Neudert, A.; Hicken, R. J.; Cavill, S. A.; Shelford, L. R.; van der Laan, G.; Telling, N. D.; Childress, J. R.; Katine, J. A.; Shafer, P.; Arenholz, E.

2010-10-14

369

X-ray fluorescence measurements of the surface elemental composition of asteroid 433 Eros  

NASA Astrophysics Data System (ADS)

We report major element ratios determined for the S-class asteroid 433 Eros using remote-sensing x-ray fluorescence spectroscopy with the near-Earth asteroid rendezvous Shoemaker x-ray spectrometer (XRS). Data analysis techniques and systematic errors are described in detail. Data acquired during five solar flares and during two extended "quiet Sun" periods are presented; these results sample a representative portion of the asteroid's surface. Although systematic uncertainties are potentially large, the most internally consistent and plausible interpretation of the data is that Eros has primitive Mg/Si, Al/Si, Ca/Si and Fe/Si ratios, closely similar to H or R chondrites. Global differentiation of the asteroid is ruled out. The S/Si ratio is much lower than that of chondrites, probably reflecting impact-induced volatilization and/or photo- or ion-induced sputtering of sulfur at the surface of the asteroid. An alternative explanation for the low S/Si ratio is that it reflects a limited degree of melting with loss of an FeS-rich partial melt. Size-sorting processes could lead to segregation of Fe-Ni metal from silicates within the regolith of Eros; this could indicate that the Fe/Si ratios determined by the x-ray spectrometer are not representative of the bulk Eros composition.

Nittler, L. R.; Starr, R. D.; Lim, L.; McCoy, T. J.; Burbine, T. H.; Reedy, R. C.; Trombka, J. I.; Gorenstein, P.; Squyres, S. W.; Boynton, W. V.; McClanahan, T. P.; Bhangoo, J. S.; Clark, P. E.; Murphy, M. E.; Killen, R.

2001-12-01

370

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

371

Proton-induces and x-ray induced fluorescence analysis of scoliotic tissue  

SciTech Connect

Adolescent idiopathic scoliosis is characterized by a curvature or assymetry of the spine which may become progressively more severe, with clinical symptoms appearing just prior to, or during, puberty. The incidence for scoliosis in the age group from 12 to 14 years of age has been reported as high as 8 to 10%, with more than 80% of the cases occurring in females. Although pathologic changes exist in muscles from both sides of the spinal curvature, and no statistically significant side differences have been reported, morphologic changes suggest that the concanve side is the most affected. This paper reports our preliminary data on the elemental composition of individual muscle fibers derived from convex, concave and gluteal scoliotic muscle, and erythrocytes from scoliotic and normal patients, analyzed by proton induced x-ray emission (PIXE) and x-ray fluorescence spectroscopy (XRF). A new type of specimen holder was designed for this study which offers low x-ray background, minimal absorption and maintenance of a moist environment around the specimen.

Panessa-Warren, B J; Kraner, H W; Jones, K W; Weiss, L S

1980-02-01

372

The fluorescence-dominated X-ray spectrum of the spiral galaxy NGC 6552  

NASA Technical Reports Server (NTRS)

A hard X-ray source with a 2-10 keV flux of approximately 6 x 10(exp -13) ergs/sec/sq cm was detected with ASCA in the north ecliptic pole region. It is identified with the spiral galaxy NGC 6552 at a redshift of z = 0.026, which is optically classified as a Seyfert 2 galaxy. The X-ray spectrum consists of a series of atomic K-emission lines from (nearly-) neutral species of at least seven abundant elements, and a heavily absorbed (N(sub H) approx. = 6 x 10(exp 23)/sq cm) hard continuum. The iron line has an equivalent width as large as approximately 0.9 keV. Our results show that NGC 6552 is an extreme type 2 Seyfert galaxy, in which the fluorescent lines are produced when hard X-rays from a hidden active nucleus are reflected off thick cool matter into our line of sight. The intrinsic 2-10 keV luminosity of the nucleus is estimated to be at least 6 x 10(exp 42) ergs/s.

Fukazawa, Yasushi; Makishima, Kazuo; Ebisawa, Ken; Fabian, Andrew C.; Gendreau, Keith C.; Ikebe, Yasushi; Iwasawa, Kazushi; Kii, Tsuneo; Mushotzky, Richard F.; Ohashi, Takaya

1994-01-01

373

Trace element abundance determinations by Synchrotron X Ray Fluorescence (SXRF) on returned comet nucleus mineral grains  

NASA Technical Reports Server (NTRS)

Trace element analyses were performed on bulk cosmic dust particles by Proton Induced X Ray Emission (PIXE) and Synchrotron X Ray Fluorescence (SXRF). When present at or near chondritic abundances the trace elements K, Ti, Cr, Mn, Cu, Zn, Ga, Ge, Se, and Br are presently detectable by SXRF in particles of 20 micron diameter. Improvements to the SXRF analysis facility at the National Synchrotron Light Source presently underway should increase the range of detectable elements and permit the analysis of smaller samples. In addition the Advanced Photon Source will be commissioned at Argonne National Laboratory in 1995. This 7 to 8 GeV positron storage ring, specifically designed for high-energy undulator and wiggler insertion devices, will be an ideal source for an x ray microprobe with one micron spatial resolution and better than 100 ppb elemental sensitivity for most elements. Thus trace element analysis of individual micron-sized grains should be possible by the time of the comet nucleus sample return mission.

Flynn, G. J.; Sutton, S. R.

1989-01-01

374

X-ray fluorescence analysis of iron and manganese distribution in primary dopaminergic neurons  

PubMed Central

Transition metals have been suggested to play a pivotal role in the pathogenesis of Parkinson's disease. X-ray microscopy combined with a cryogenic setup is a powerful method for elemental imaging in low concentrations and high resolution in intact cells, eliminating the need for fixation and sectioning of the specimen. Here, we performed an elemental distribution analysis in cultured primary midbrain neurons with a step size in the order of 300 nm and ? 0.1 ppm sensitivity under cryo conditions by using X-ray fluorescence microscopy. We report the elemental mappings on the subcellular level in primary mouse dopaminergic (DAergic) and non-DAergic neurons after treatment with transition metals. Application of Fe2+ resulted in largely extracellular accumulation of iron without preference for the neuronal transmitter subtype. A quantification of different Fe oxidation states was performed using X-ray absorption near edge structure analysis. After treatment with Mn2+, a cytoplasmic/paranuclear localization of Mn was observed preferentially in DAergic neurons, while no prominent signal was detectable after Mn3+ treatment. Immunocytochemical analysis correlated the preferential Mn uptake to increased expression of voltage-gated calcium channels in DAergic neurons. We discuss the implications of this differential elemental distribution for the selective vulnerability of DAergic neurons and Parkinson's disease pathogenesis.

Ducic, Tanja; Barski, Elisabeth; Salome, Murielle; Koch, Jan C; Bahr, Mathias; Lingor, Paul

2013-01-01

375

Maia X-ray fluorescence imaging: Capturing detail in complex natural samples  

NASA Astrophysics Data System (ADS)

Motivated by the challenge of capturing complex hierarchical chemical detail in natural material from a wide range of applications, the Maia detector array and integrated realtime processor have been developed to acquire X-ray fluorescence images using X-ray Fluorescence Microscopy (XFM). Maia has been deployed initially at the XFM beamline at the Australian Synchrotron and more recently, demonstrating improvements in energy resolution, at the P06 beamline at Petra III in Germany. Maia captures fine detail in element images beyond 100 M pixels. It combines a large solid-angle annular energy-dispersive 384 detector array, stage encoder and flux counter inputs and dedicated FPGA-based real-time event processor with embedded spectral deconvolution. This enables high definition imaging and enhanced trace element sensitivity to capture complex trace element textures and place them in a detailed spatial context. Maia hardware and software methods provide per pixel correction for dwell, beam flux variation, dead-time and pileup, as well as off-line parallel processing for enhanced throughput. Methods have been developed for real-time display of deconvoluted SXRF element images, depth mapping of rare particles and the acquisition of 3D datasets for fluorescence tomography and XANES imaging using a spectral deconvolution method that tracks beam energy variation.

Ryan, C. G.; Siddons, D. P.; Kirkham, R.; Li, Z. Y.; de Jonge, M. D.; Paterson, D. J.; Kuczewski, A.; Howard, D. L.; Dunn, P. A.; Falkenberg, G.; Boesenberg, U.; De Geronimo, G.; Fisher, L. A.; Halfpenny, A.; Lintern, M. J.; Lombi, E.; Dyl, K. A.; Jensen, M.; Moorhead, G. F.; Cleverley, J. S.; Hough, R. M.; Godel, B.; Barnes, S. J.; James, S. A.; Spiers, K. M.; Alfeld, M.; Wellenreuther, G.; Vukmanovic, Z.; Borg, S.

2014-04-01

376

Background estimation methods for quantitative x-ray fluorescence analysis of gold nanoparticles in biomedical applications  

NASA Astrophysics Data System (ADS)

Accurate background estimation to isolate the fluorescence signals is an important issue for quantitative X-ray fluorescence (XRF) analysis of gold nanoparticles (GNPs). Though a good estimation can be obtained experimentally through acquiring the background spectrum of water solution, it inevitably leads to unnecessary second exposure in reality. Thus, several numerical methods such as trapezoidal shape estimation, interpolation by polynomial fitting and SNIP (Statistics sensitive Nonlinear Iterative Peak-Clipping) algorithm are proposed to achieve this goal. This paper aims to evaluate the estimation results calculated by these numerical methods through comparing with that acquired using the experimental way, in term of mean squared error (MSE). Four GNP/water solutions with various concentrations from 0.0% to 1.0% by weight are prepared. Then, ten spectra are acquired for each solution for further analysis, under the identical condition of using pencil beam x-ray and single spectrometer. Finally, the experimental and numerical methods are performed on these spectra within the optimally determined energy window and their statistical characteristics are analyzed and compared. These numerical background estimation methods as well as the evaluation methods can be easily extended to analyze the fluorescence signals of other nanoparticle biomarkers such as gadolinium, platinum and Barium in multiple biomedical applications.

Ren, Liqiang; Wu, Di; Li, Yuhua; Chen, Wei R.; Liu, Hong

2014-02-01

377

The Bionanoprobe: hard X-ray fluorescence nanoprobe with cryogenic capabilities.  

PubMed

Hard X-ray fluorescence microscopy is one of the most sensitive techniques for performing trace elemental analysis of biological samples such as whole cells and tissues. Conventional sample preparation methods usually involve dehydration, which removes cellular water and may consequently cause structural collapse, or invasive processes such as embedding. Radiation-induced artifacts may also become an issue, particularly as the spatial resolution increases beyond the sub-micrometer scale. To allow imaging under hydrated conditions, close to the `natural state', as well as to reduce structural radiation damage, the Bionanoprobe (BNP) has been developed, a hard X-ray fluorescence nanoprobe with cryogenic sample environment and cryo transfer capabilities, dedicated to studying trace elements in frozen-hydrated biological systems. The BNP is installed at an undulator beamline at sector 21 of the Advanced Photon Source. It provides a spatial resolution of 30?nm for two-dimensional fluorescence imaging. In this first demonstration the instrument design and motion control principles are described, the instrument performance is quantified, and the first results obtained with the BNP on frozen-hydrated whole cells are reported. PMID:24365918

Chen, S; Deng, J; Yuan, Y; Flachenecker, C; Mak, R; Hornberger, B; Jin, Q; Shu, D; Lai, B; Maser, J; Roehrig, C; Paunesku, T; Gleber, S C; Vine, D J; Finney, L; VonOsinski, J; Bolbat, M; Spink, I; Chen, Z; Steele, J; Trapp, D; Irwin, J; Feser, M; Snyder, E; Brister, K; Jacobsen, C; Woloschak, G; Vogt, S

2014-01-01

378

New Homogeneous Standards by Atomic Layer Deposition for Synchrotron X-ray Fluorescence and Absorption Spectroscopies.  

SciTech Connect

Quantification of synchrotron XRF analyses is typically done through comparisons with measurements on the NIST SRM 1832/1833 thin film standards. Unfortunately, these standards are inhomogeneous on small scales at the tens of percent level. We are synthesizing new homogeneous multilayer standards using the Atomic Layer Deposition technique and characterizing them using multiple analytical methods, including ellipsometry, Rutherford Back Scattering at Evans Analytical, Synchrotron X-ray Fluorescence (SXRF) at Advanced Photon Source (APS) Beamline 13-ID, Synchrotron X-ray Absorption Spectroscopy (XAS) at Advanced Light Source (ALS) Beamlines 11.0.2 and 5.3.2.1 and by electron microscopy techniques. Our motivation for developing much-needed cross-calibration of synchrotron techniques is borne from coordinated analyses of particles captured in the aerogel of the NASA Stardust Interstellar Dust Collector (SIDC). The Stardust Interstellar Dust Preliminary Examination (ISPE) team have characterized three sub-nanogram, {approx}1{micro}m-sized fragments considered as candidates to be the first contemporary interstellar dust ever collected, based on their chemistries and trajectories. The candidates were analyzed in small wedges of aerogel in which they were extracted from the larger collector, using high sensitivity, high spatial resolution >3 keV synchrotron x-ray fluorescence spectroscopy (SXRF) and <2 keV synchrotron x-ray transmission microscopy (STXM) during Stardust ISPE. The ISPE synchrotron techniques have complementary capabilities. Hard X-ray SXRF is sensitive to sub-fg mass of elements Z {ge} 20 (calcium) and has a spatial resolution as low as 90nm. X-ray Diffraction data were collected simultaneously with SXRF data. Soft X-ray STXM at ALS beamline 11.0.2 can detect fg-mass of most elements, including cosmochemically important oxygen, magnesium, aluminum and silicon, which are invisible to SXRF in this application. ALS beamline 11.0.2 has spatial resolution better than 25 nm. Limiting factors for Stardust STXM analyses were self-imposed limits of photon dose due to radiation damage concerns, and significant attenuation of <1500 eV X-rays by {approx}80{micro}m thick, {approx}25 mg/cm{sup 3} density silica aerogel capture medium. In practice, the ISPE team characterized the major, light elements using STXM (O, Mg, Al, Si) and the heavier minor and trace elements using SXRF. The two data sets overlapped only with minor Fe and Ni ({approx}1% mass abundance), providing few quantitative cross-checks. New improved standards for cross calibration are essential for consortium-based analyses of Stardust interstellar and cometary particles, IDPs. Indeed, they have far reaching application across the whole synchrotron-based analytical community. We have synthesized three ALD multilayers simultaneously on silicon nitride membranes and silicon and characterized them using RBS (on Si), XRF (on Si{sub 3}N{sub 4}) and STXM/XAS (holey Si{sub 3}N{sub 4}). The systems we have started to work with are Al-Zn-Fe and Y-Mg-Er. We have found these ALD multi-layers to be uniform at {micro}m- to nm scales, and have found excellent consistency between four analytical techniques so far. The ALD films can also be used as a standard for e-beam instruments, eg., TEM EELS or EDX. After some early issues with the consistency of coatings to the back-side of the membrane windows, we are confident to be able to show multi-analytical agreement to within 10%. As the precision improves, we can use the new standards to verify or improve the tabulated cross-sections.

Butterworth, A.L.; Becker, N.; Gainsforth, Z.; Lanzirotti, A.; Newville, M.; Proslier, T.; Stodolna, J.; Sutton, S.; Tyliszczak, T.; Westphal, A.J.; Zasadzinski, J. (UCB)

2012-03-13

379

Synchrotron total reflection X-ray fluorescence at BL-16 microfocus beamline of Indus-2  

NASA Astrophysics Data System (ADS)

Determination of ultra trace elements is important in many disciplines both in basic and applied sciences. Numerous applications show their importance in medical science, environmental science, materials science, food processing and semiconductor industries and in maintaining the quality control of ultra pure chemicals and reagents. We report commissioning of a synchrotron based total reflection x-ray fluorescence (TXRF) facility on the BL-16 microfocus beamline of Indus-2. This paper describes the performance of the BL-16 TXRF spectrometer and the detailed description of its capabilities through examples of measured results.

Tiwari, M. K.; Singh, A. K.; Das, Gangadhar; Chowdhury, Anupam; Lodha, G. S.

2014-04-01

380

Preliminary testing of a prototype portable X-ray fluorescence spectrometer  

NASA Technical Reports Server (NTRS)

A portable X-ray fluorescence spectrometer for use as an analyzer in mineral resource investigative work was built and tested. The prototype battery powered spectrometer, measuring 11 by 12 by 5 inches and weighing only about 15 pounds, was designed specifically for field use. The spectrometer has two gas proportional counters and two radioactive sources, Cd (10a) and Fe (55). Preliminary field and laboratory tests on rock specimens and rock pulps have demonstrated the capability of the spectrometer to detect 33 elements to date. Characteristics of the system present some limitations, however, and further improvements are recommended.

Patten, L. L.; Anderson, N. B.; Stevenson, J. J.

1982-01-01

381

Lead nephropathy: In vivo x ray fluorescence (XRF) for assessing body lead stores  

SciTech Connect

The EDTA lead mobilization test has proven of value in the diagnosis of renal disease due to lead (lead nephropathy) but is unsuitable for large scale studies in patients with end-stage renal disease. A rapid, safe, non-invasive technique for determining body lead stores by in vivo tibial x ray fluorescence (XRF) is described. These studies show that the chelation test can be replaced by in vivo XRF in patients with end-stage renal disease. XRF, for the first time, will permit epidemiologic studies of large populations which may be at risk for lead nephropathy from excessive exposure to environmental lead. 15 refs., 2 figs.

Wedeen, R.P.; Batuman, V.; Quinless, F.; Williams, F.H. Jr.; Bogden, J.; Schidlovsky, G.; Jones, K.W.

1986-01-01

382

A high resolution x-ray fluorescence spectrometer for near edge absorption studies  

SciTech Connect

A high resolution fluorescence spectrometer using a Johann geometry in a back scattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near edge absorption spectrum of dysprosium nitrate. 10 refs., 4 figs.

Stojanoff, V.; Hamalainen, K.; Siddons, D.P.; Hastings, J.B.; Berman, L.E.; Cramer, S.; Smith, G.

1991-12-31

383

A high resolution x-ray fluorescence spectrometer for near edge absorption studies  

SciTech Connect

A high resolution fluorescence spectrometer using a Johann geometry in a back scattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near edge absorption spectrum of dysprosium nitrate. 10 refs., 4 figs.

Stojanoff, V.; Hamalainen, K.; Siddons, D.P.; Hastings, J.B.; Berman, L.E.; Cramer, S.; Smith, G.

1991-01-01

384

X-Ray fluorescence analysis of trace elements in fruit juice  

NASA Astrophysics Data System (ADS)

X-Ray fluorescence spectrometry is applied to the determination of trace elements in fruit juice characterized by a high content of sugar and other soluble solid substances. Samples are prepared by evaporation, carbonization and pressing into discs. The synthesis of standards is described in detail. All element concentrations are directly estimated from linear calibration curves obtained without any matrix correction. The results of the analysis are in good agreement with those given by inductively coupled plasma-atomic emission spectrometry and atomic absorption spectrometry techniques.

Bao, Sheng-Xiang; Wang, Zhi-Hong; Liu, Jing-Song

1999-12-01

385

Portable X-ray fluorescence instruments for the analysis of lead in paints.  

PubMed Central

In a study in the laboratories of the Chicago Board of Health, the results from determination of lead in paint films by X-ray fluorescence were compared with results from determination by atomic absorption. Portable instruments of three suppliers were used for X-ray fluorescence measurements. An improved version of one of these instruments was also tested. The results of X-ray fluorescence readings on painted card stock panels with one of these instruments compared satisfactorily with the results as determined by the atomic absorption method at levels below 10 mg of lead per square centimeter. Readings on multiple layers of these panels were additive and independent of the order of these panels. All four instruments were tested in the laboratory on painted surfaces from the walls of condemned buildings. The most recent version of each instrument gave a correlation coefficient of 0.96 or better for the linear regression of lead values in milligrams per square centimeter by atomic absorption against instrument readings. It was calculated that a reading of 3.2 or greater on any of the instruments would indicate with greater than 95 percent confidence that 1 mg or more of lead per square centimeter would be found when a sample of the paint was analyzed by atomic absorption. When the readings of one of the instruments showed lead to be absent, that result would inidcate with better than 95 percent confidence that less than 1 mg of lead per square centimeter would be found by the atomic absorption method. Portable X-ray fluorescence instruments can be used in situ to determine whether the walls of a building give readings for lead above the range of 0 to 3.2. Walls with readings above this range can be considered to have 1 mg or more of lead per square centimeter and would not be in conformance with the code of the City of Chicago. Samples would need to be taken for analysis in the laboratory by atomic absorption only from those walls with readings within the range of 0 to 3.2. Images p224-a 1. 2. 3.

Kaplan, E H; Lilley, M D; Schaefer, R F; Cade, B; Desai, A; Padva, A; Orbach, H G

1975-01-01

386

Combined backscatter Moessbauer spectrometer/x ray fluorescence analyzer (BaMS/XRF) for extraterrestrial surfaces  

NASA Technical Reports Server (NTRS)

We have designed and tested a prototype combined backscatter Moessbauer spectrometer and x-ray fluorescence analyzer (BaMS/XRF). A space qualified instrument based on this design would be suitable for in-situ use on planetary missions to the surfaces of the Moon (Artemis and lunar outpost), Mars (MESUR), asteroids, or other solid solar system objects. The BaMS/XRF instrument is designed to be capable of concurrent sample analyses for the mineralogy of iron-bearing phases and elemental composition without the need for sample preparation.

Shelfer, T. D.; Wills, E. L.; Agresti, D. G.; Pimperl, M. M.; Shen, M. H.; Morris, R. V.; Nguyen, T.

1993-01-01

387

An x-ray fluorescence study of lake sediments from ancient Turkey using synchrotron radiation.  

SciTech Connect

Sediments from relic Lake Golbasi were analyzed by X-ray fluorescence with synchrotrons radiation to determine changes in element concentrations over time with selected elements serving as proxies for environmental change. Increases in Ca and Sr suggest soil formation during a dry period, from ca. 4500 BC to ca. 200 AD at which point K, Rb, Zr, Ti, and Y increase, indicating the return of a wet environment. Soil erosion, represented by Cr and Ni, increases ca. 7000 BC, probably as a consequence of environmental change, prior to suggested exploitation of natural resources by the newly urbanized society of the third millennium BC.

Alatas, A.; Alp, E. E.; Friedman, E. S.; Jennings, G.; Johnson, C. E.; Lai, B.; Mini, S. M.; Sato, Y.; Wilkinson, T. J.; Yener, K. A.

1999-03-10

388

Trace element determination in drugs by total-reflection X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

The capability of total-reflection X-ray fluorescence spectrometry (TXRF) for the determination of trace elements in drugs is described. Various samples of lecithin, insulin, procaine and tryptophan of different origin were investigated. The element concentrations provide element fingerprints which offer the possibility to discriminate between different batches of the analysed substances originating from different production or purification processes. TXRF facilitates the characterization of such samples without extensive pre-treatment, and provides fast multi-element determination of elements with atomic numbers 14< Z<92 based on matrix-independent quantification by means of an internal standard.

Wagner, M.; Rostam-Khani, P.; Wittershagen, A.; Rittmeyer, Claudia; Kolbesen, B. O.; Hoffmann, H.

1997-07-01

389

Synchrotron based X-ray fluorescence activities at Indus-2: An overview  

NASA Astrophysics Data System (ADS)

X-Ray fluorescence (XRF) spectrometry is a powerful non-destructive technique for elemental analysis of materials at bulk and trace concentration levels. Taking into consideration several advantages of the synchrotron based XRF technique and to fulfill the requirements of Indian universities users we have setup a microfocus XRF beamline (BL-16) on Indus-2 synchrotron light source. The beamline offers a wide range of usages - both from research laboratories and industries; and for researchers working in diverse fields. A brief overview of the measured performance of the beamline, design specifications including various attractive features and recent research activities carried out on the BL-16 beamline are presented.

Tiwari, M. K.

2014-04-01

390

Application of grazing incidence x-ray fluorescence technique to discriminate and quantify implanted solar wind  

SciTech Connect

NASA launched the Genesis return mission to obtain pristine solar wind samples in order to better understand solar wind mechanics, solar physics, and solar system evolution. Unfortunately, the probe crash-landed shattering the collector plates necessitating the application of a grazing incidence x-ray fluorescence technique. This nondestructive methodology differentiates the terrestrial contamination from the low concentration implanted solar wind. Using this technique, the elemental depth distribution is obtained resulting in the determination of absolute solar wind elemental abundance. We describe this application and present the solar wind Fe concentration determination as an example.

Kitts, K.; Choi, Y. [Department of Geology and Environment Geosciences, Northern Illinois University, Davis Hall 312, Normal Road, DeKalb, Illinois 60115 (United States); Eng, P. J.; Ghose, S. K.; Sutton, S. R. [Department of Geophysical Sciences and Consortium for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637 (United States); Rout, B. [Department of Physics, University of North Texas, Denton, Texas 76203 (United States)

2009-03-15

391

First combined total reflection X-ray fluorescence and grazing incidence X-ray absorption spectroscopy characterization of aeolian dust archived in Antarctica and Alpine deep ice cores  

Microsoft Academic Search

Aeolian mineral dust archived in polar and mid latitude ice cores represents a precious proxy for assessing environmental and climatic variations at different timescales. In this respect, the identification of dust mineralogy plays a key role. In this work we performed the first preliminary X-ray absorption spectroscopy (XAS) experiments on mineral dust particles extracted from Antarctic and from Alpine firn

G. Cibin; A. Marcelli; V. Maggi; M. Sala; F. Marino; B. Delmonte; S. Albani; S. Pignotti

2008-01-01

392

Total reflection X-ray fluorescence spectrometers for multielement analysis: status of equipment  

NASA Astrophysics Data System (ADS)

Multielement analysis by total reflection X-ray fluorescence spectrometry has evolved during two decades. At present commercial equipment is available for chemical analysis of all types of biological and mineral samples. The electronic industry has also benefited from scientific and technological developments in this field due to new instrumentation to determine contamination on the surface of silicon wafers (the equipment will not be covered in this paper). The basic components of the spectrometers can be summarized as follows: (a) excitation source; (b) geometric arrangement (optics) for collimation and monochromatization of the primary radiation; (c) X-ray detector; and (d) software for operation of the instrument, data acquisition and spectral deconvolution to determine the concentrations of the elements (quantitative analysis). As an optional feature one manufacturer offers a conventional 45° geometry for direct excitation. Personal communications of the author and commercial brochures available have allowed us to list the components used in TXRF for multielement analysis. Excitation source: high-power sealed X-ray tubes, output from 1300 to 3000 W, different mixed alloy anodes Mo/W are used but molybdenum, tungsten and copper are common; single anode metal ceramic low power X-ray tubes, output up to 40 W. Excitation systems can be customized according to the requirements of the laboratory. Detector: silicon-lithium drifted semiconductor detector liquid nitrogen cooled; or silicon solid state thermoelectrically cooled detector (silicon drift detector SDD and silicon-PIN diode detector). Optics: multilayer monochromator of silicon-tungsten, nickel-carbon or double multilayer monochromator. Electronics: spectroscopy amplifier, analog to digital converter adapted to a PC compatible computer with software in a Windows environment for the whole operation of the spectrometer and for qualitative/quantitative analysis of samples are standard features in the production of this instrument. The detection limits reported in the literature are presented; pricing, analytical capability, ease of operation, calibration and optical alignment as well as technical support are also discussed.

Ayala Jiménez, Rony E.

2001-11-01

393

Metabolism of selenite in human lung cancer cells: X-ray absorption and fluorescence studies  

PubMed Central

Selenite is an inorganic form of selenium that has a cytotoxic effect against several human cancer cell lines: one or more selenite metabolites are considered to be responsible for its toxicity. X-ray absorption spectroscopy was used to monitor Se speciation in A549 human lung cancer cells incubated with selenite over 72 h. As anticipated, selenodiglutathione and elemental Se both comprised a large proportion of Se in the cells between 4 and 72 h after treatment, which is in accordance with the reductive metabolism of selenite in the presence of glutathione and glutathione reductase/NADPH system. Selenocystine was also present in the cells, but was only detected as a significant component between 24 h and 48 h concomitant with a decrease in the proportion of selenocysteine and the viability of the cells. The change in speciation from the selenol, selenocysteine, to the diselenide, selenocystine, is indicative of a change in the redox status of the cells to a more oxidizing environment, likely brought about by metabolites of selenite. X-ray fluorescence microscopy of single cells treated with selenite for 24 h revealed a punctate distribution of Se in the cytoplasm. The accumulation of Se was associated with a greater than two-fold increase in Cu, which was colocalized with Se. Selenium K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy revealed Se-Se and Se-S bonding, but not Se-Cu bonding, despite the spatial association of Se and Cu. Microprobe X-ray absorption near-edge structure spectroscopy (?-XANES) showed that the highly localized Se species was mostly elemental Se.

Weekley, Claire M.; Aitken, Jade B.; Vogt, Stefan; Finney, Lydia A.; Paterson, David J.; de Jonge, Martin D.; Howard, Daryl L.; Witting, Paul K.; Musgrave, Ian F.; Harris, Hugh H.

2011-01-01

394

Metabolism of selenite in human lung cancer cells: X-ray absorption and fluorescence studies.  

PubMed

Selenite is an inorganic form of selenium that has a cytotoxic effect against several human cancer cell lines: one or more selenite metabolites are considered to be responsible for its toxicity. X-ray absorption spectroscopy was used to monitor Se speciation in A549 human lung cancer cells incubated with selenite over 72 h. As anticipated, selenodiglutathione and elemental Se both comprised a large proportion of Se in the cells between 4 and 72 h after treatment, which is in accordance with the reductive metabolism of selenite in the presence of glutathione and glutathione reductase/NADPH system. Selenocystine was also present in the cells but was only detected as a significant component between 24 and 48 h concomitant with a decrease in the proportion of selenocysteine and the viability of the cells. The change in speciation from the selenol, selenocysteine, to the diselenide, selenocystine, is indicative of a change in the redox status of the cells to a more oxidizing environment, likely brought about by metabolites of selenite. X-ray fluorescence microscopy of single cells treated with selenite for 24 h revealed a punctate distribution of Se in the cytoplasm. The accumulation of Se was associated with a greater than 2-fold increase in Cu, which was colocalized with Se. Selenium K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy revealed Se-Se and Se-S bonding, but not Se-Cu bonding, despite the spatial association of Se and Cu. Microprobe X-ray absorption near-edge structure spectroscopy (?-XANES) showed that the highly localized Se species was mostly elemental Se. PMID:21957893

Weekley, Claire M; Aitken, Jade B; Vogt, Stefan; Finney, Lydia A; Paterson, David J; de Jonge, Martin D; Howard, Daryl L; Witting, Paul K; Musgrave, Ian F; Harris, Hugh H

2011-11-16

395

Ombroscopie en Rayons X dans les Experiences d'Implosion (X ray Shadowscopy in Implosion Experiments).  

National Technical Information Service (NTIS)

An experiment was carried out concerning the illumination with an x ray beam of a microballoon being imploded, to deduce from the measured absorption the density of the matter compressed in the implosion. The space resolution and imagery problems were sol...

R. Benattar J. Boudene E. Fabre V. Malka A. Michard

1988-01-01

396

Application of imaging plate to x-ray imaging and spectroscopy in laser plasma experiments  

SciTech Connect

We report recent progress of x-ray diagnostic techniques in laser plasma experiment with using imaging plates. Imaging plate is a photo-stimulable phosphor screen (BaF(Br0.85,10.15):Eu{sup 2+}) deposited on flexible metal or plastic substrate. We applied the imaging plate to x-ray microscopy in laser fusion experiment experiments. Self-emission x-ray images of imploded core were obtained successfully with using imaging plate and high magnification target mounted pinhole arrays. The imaging plates were applied also in ultra-intense laser experiment at the Rutherford Appleton Laboratory. Small samarium foil was irradiated by high intensity laser pulse from the Vulcan laser system. The k shell x-rays from the foil ({approx}40keV) was used as a line x-ray source for microscopic radiography. Performance of imaging plate on high-energy x-ray backlit radiography was demonstrated by imaging sinusoidal grooves of 6um amplitude on a Au foil. Detailed spectrum of k shell x-ray from Cu embedded foil target was successfully observed by fully coupling imaging plate with a highly ordered pyrolytic graphite crystal spectrometer. The performances of the imaging plates evaluated in actual laser plasma experiments will be presented.

Izumi, N; Snavely, R; Gregori, G; Koch, J A; Park, H; Remington, B A

2006-04-25

397

InFOCuS balloon-borne hard x-ray experiment with multilayer supermirror x-ray telescope  

Microsoft Academic Search

We have been developing the high throughput hard X-ray telescope, using reflectors coated with the depth graded multilayer known as supermirror, which is considered to be a key technology for future satellite hard X-ray imaging missions. InFOC(mu) $S, the International Focusing Optics Collaboration for (mu) -Crab Sensitivity is the project of the balloon observation of a cosmic hard X-ray source

Yuzuru Tawara; Kojun Yamashita; Yasushi Ogasaka; Keisuke Tamura; Kazutoshi Haga; Takashi Okajima; Satoshi Ichimaru; Seiji Takahashi; Arifumi Gotou; Hideo Kitou; Shinichi Fukuda; Yuichi Kamata; Akihiro Furuzawa; Fumie Akimoto; Tsutomu Yoshioka; Kazuo Kondou; Yoshito Haba; Takeshi Tanaka; Hideyo Kunieda; Kazutami Misaki; Jack Tuller; Peter J. Serlemitsos; Kai-Wing Chan; Yang Soong; Scott M. Owens; Fred Berendse; W. H. Baugartner; Hans Krimm; H. Bradford Barber; Erick T. Young

2002-01-01

398

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

399

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

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

400

Treatment of Acid Mine Drainage. Column experiments and X-ray microtomography.  

NASA Astrophysics Data System (ADS)

Column experiments to emulate the behavior of passive treatment systems for acid mine drainage (AMD) were carried out. Synthetic acidic solutions made up of H2SO4 and Fe (III) (200-1500 ppm) at pH 2 circulated through columns filled with grains of calcite, aragonite or dolomite at a constant flow rate (6e-7 or 1e-6 m3/m2//s). Grain size ranged between 1 and 2 mm. The columns worked as an efficient barrier for some time, increasing the pH of the circulating solution to about 7 and removing its metal content. Results show that acidic solution reacts with the carbonate surfaces and newly precipitated gypsum coats the carbonate grains, eventually causing the passivation of the system. Metal-oxyhydroxysulfates precipitate mostly at the central regions of pore space. Variation in porosity and secondary mineral precipitation (gypsum, goethite, schwertmannite in some cases) was investigated with X-ray microtomography. Reaction fronts advance along the columns (precipitation of gypsum and Fe-oxyhydroxysulfates). Variation in porosity due to secondary mineral precipitation is quantified and formation of preferential flow paths in the porous medium is observed. In addition, X-ray fluorescence was performed to map the metal content and metal distribution.

Offeddu, Francesco; Tiseanu, Ion; Cama, Jordi; Soler, Josep M.; Ayora, Carlos

2010-05-01

401

Laboratory x-ray spectroscopy experiments in support of NASA`s x-ray satellite missions  

SciTech Connect

With support from NASA, we are performing a series of laboratory astrophysics investigations designed to address fundamental uncertainties in basic atomic physics processes relevant to the interpretation of discrete X-ray spectra of cosmic plasmas. Moderate resolution spectra acquired by the ASCA Observatory already demonstrate the inadequacy of currently available spectral modelling codes for this wavelength band. With the upcoming launches of AXAF, XMM, ASTRO E, and Spektrum Roentgen-Gamma, the demand for significant advances in this field will increase dramatically. Our program is based on the exploitation of the Electron Beam Ion Trap facility at the Lawrence Livermore National Laboratory, and a unique set of spectrometers and experimental techiques specifically developed for this purpose. Recent experiments have been devoted to definitive measurements of line emissivities for iron L-shell ions in optically thin, collisional plasmas.

Kahn, S. M., Columbia University

1998-05-22

402

Synchrotron Radiation {mu}-X Ray Fluorescence on Multicellular Tumor Spheroids  

SciTech Connect

Synchrotron Radiation micro X-Ray Fluorescence (SR {mu}-XRF) was applied for the first time to map the trace element content on Multicellular Tumor Spheroids (MTS), i.e. human cell clusters used as an in vitro model for testing micrometastases responses to antitumoral drugs. In particular, immunotoxin molecules composed of a carrier protein (Transferrin) bound to a powerful cytotoxin (Ricin A), were here considered as representatives of a class of therapheutic macromolecules used in cancer theraphy. Spheroids included in polyacrylamide gel and placed inside quartz capillaries were studied at the ESRF ID22 beamline using a 15 keV monochromatic photon microbeam. Elemental maps (of Fe, Cu, Zn and Pb) on four groups of spheroids grown under different conditions were studied: untreated, treated only with the carrier molecule or with the toxin alone, and with the complete immunotoxin molecule (carrier+toxin). The results indicate that the distribution of Zn and, to some extent, Cu in the spheroid cells is homogeneous and independent of the treatment type. Total Reflection X-Ray Fluorescence (TR-XRF) was also applied to quantify the average trace element content in the spheroids. Future developments of the technique are finally outlined on the basis of these preliminary results.

Burattini, E. [Istituto Nazionale di Fisica Nucleare- Laboratori di Frascati, via E. Fermi 40, I-00044 Frascati (Italy); Universita degli Studi di Verona -Dipartimento di Informatica, Strada LeGrazie 15, I-37134 Verona (Italy); Cinque, G. [Istituto Nazionale di Fisica Nucleare- Laboratori di Frascati, via E. Fermi 40, I-00044 Frascati (Italy); Bellisola, G.; Fracasso, G.; Colombatti, M. [Universita degli Studi di Verona-Dip. Patologia, Sez. Immunologia, P.le A.L. Scuro, I-37134 Verona (Italy); Monti, F. [Universita degli Studi di Verona-Dipartimento di Informatica, Strada LeGrazie 15, I-37134 Verona (Italy)

2003-01-24

403

Feasibility of noninvasive analysis of lead in the human tibia by soft x-ray fluorescence  

SciTech Connect

A postmortem study was conducted to assess the feasibility of measuring bone lead concentrations noninvasively in vivo. Characteristic L x rays were induced with an external source of /sup 125/I in the superficial tibial cortex of the intact legs of six adults who had no history of occupational exposure to lead. Tibial lead concentrations in the same bones subsequently determined by flameless atomic absorption spectroscopy varied from 15 to 35 ..mu..g Pb/g wet weight. The upper limit for the modern normal range of lead in the bone is about 25 mg Pb/g wet tissue. The linear correlation coefficient (r) between the measurements made with x-ray fluorescence and lead concentration by absorption spectroscopy was 0.90. Radiation doses of 10 mGy (1 rad) to 1 cm/sup 2/ of skin, with associated doses to the marrow of adjacent bone of about 0.6 mGy (60 mrad), yielded net lead fluorescence signals ranging from one to seven times the standard deviation of background.

Wielopolski, L.; Rosen, J.F.; Slatkin, D.N.; Vartsky, D.; Ellis, K.J.; Cohn, S.H.

1983-03-01

404

New results in high-resolution X-ray fluorescence spectroscopy  

NASA Astrophysics Data System (ADS)

We present some recent results dealing with resonant inelastic X-ray scattering (RIXS) on atomic targets in the 3-5 keV enegy region. In this so-called tender spectral region, the K-shell fluorescence branching ratios become reasonably large, but a full vacuum enclosure is still preferable to avoid detection efficiency loss due to the sizeable arms of high resolution crystal spectrometers. By squeezing energy resolution in the fluorescence decay channel, one may improve the spectral resolution of photoabsorption, enable separation of multielectron excitation and relaxation channels, and completely eliminate the need to scan across the selected energy range of the photon probe in order to acquire the photoabsorption spectrum. On the other hand, the spectra may be untrivially modified by effects such as interference of absorption-emission paths or structured relaxation modes, and a more elaborated modelling is needed to understand the emitted signal. We illustrate these aspects by presenting four cases: the reconstruction of Ar KM and Ar KL absorption edges from a series of highly resolved emission spectra recorded at different probe energies, the reconstruction of the Xe L3 edge from a single X-ray emission spectrum, and the analysis of the radiative Ar K-MM Auger decay preceeded by the resonant or nonresonant photon absorption.

Žitnik, Matjaž; Kav?i?, Matjaž; Bu?ar, Klemen; Miheli?, Andrej; Bohinc, Rok

2014-04-01

405

In vivo measurements of mercury using x-ray fluorescence analysis  

SciTech Connect

In this study we present the results of in vivo measurements of the mercury concentration in organs of occupationally exposed persons by the use of X-ray fluorescence analysis (XRF). The mercury concentration in the right kidney was measured in 20 occupationally exposed workers and 12 referents. The detection limit for the individual persons varied with the kidney depth (mean 26 {mu}g/g, range 12-45 {mu}g/g), was exceeded in nine of the exposed workers but in none of the referents. The mean kidney mercury concentration (including estimated concentration values below the detection limit) was 24 {mu}g/g in the group of exposed workers (group MDC 5 {mu}g/g), and for the group of referents no detectable concentration (mean 1 {mu}g/g) was hind (group MDC 6 {mu}g/g). The mean urinary mercury excretions for the two groups were 34 and 1.7 {mu}g per g creatinine. X-ray fluorescence measurements made on liver (n = 10) and thyroid (n = 8), in some of the exposed workers, revealed no measurable mercury concentrations.

Boerjesson, J.; Jonson, R.; Apsten, M. [Univ. of Goeteborg (Sweden); Mattsson, S. [Lund Univ., Malmoe (Sweden); Barregard, L.; Saellsten, G. [Univ. of Goeteborg (Sweden)

1995-12-31

406

Quantification of phosphorus in single cells using synchrotron X-ray fluorescence.  

PubMed

Phosphorus is required for numerous cellular compounds and as a result can serve as a useful proxy for total cell biomass in studies of cell elemental composition. Single-cell analysis by synchrotron X-ray fluorescence (SXRF) enables quantitative and qualitative analyses of cell elemental composition with high elemental sensitivity. Element standards are required to convert measured X-ray fluorescence intensities into element concentrations, but few appropriate standards are available, particularly for the biologically important element P. Empirical P conversion factors derived from other elements contained in certified thin-film standards were used to quantify P in the model diatom Thalassiosira pseudonana, and the measured cell quotas were compared with those measured in bulk by spectrophotometry. The mean cellular P quotas quantified with SXRF for cells on Au, Ni and nylon grids using this approach were not significantly different from each other or from those measured spectrophotometrically. Inter-cell variability typical of cell populations was observed. Additionally, the grid substrates were compared for their suitability to P quantification based on the potential for spectral interferences with P. Nylon grids were found to have the lowest background concentrations and limits of detection for P, while background concentrations in Ni and Au grids were 1.8- and 6.3-fold higher. The advantages and disadvantages of each grid type for elemental analysis of individual phytoplankton cells are discussed. PMID:20567089

Nśńez-Milland, Daliįngelis R; Baines, Stephen B; Vogt, Stefan; Twining, Benjamin S

2010-07-01

407

[Determination of major elements in soil from cancer village by X-ray fluorescence spectrometry].  

PubMed

Many social problems arise from environmental pollution, cancer village is one of the many important problems caused by pollution. The authors selected a typical cancer village where 80-100 people died of cancer in the last five years, but there are only a total of 1 200 people in this village. The authors sampled soils from crops-planted areas and detected the major elements by X-ray fluorescence spectrometry. The results showed that the contents of SiO2, TiO2, Al2O3, Fe2O3, MnO, MgO, CaO, Na2O, K2O and P2O5 in soil of this village were 66.05%, 0.66%, 11.37%, 3.93%, 0.075%, 1.97%, 5.47%, 1.90%, 2.11% and 0.20% respectively; with the precision being +/- 0.20%, +/- 0.005%, +/- 0.10%, +/- 0.10%, +/- 0.005%, +/- 0.05%, +/- 0.04%, +/- 0.08%, +/- 0.02% and +/- 0.005% respectively, which showed that X-ray fluorescence spectrometry is a good method. PMID:19271523

Wei, Zhen-Lin; Li, He; Rui, Yu-Kui

2008-11-01

408

Elemental concentration analysis in prostate tissues using total reflection X-ray fluorescence  

NASA Astrophysics Data System (ADS)

Prostate cancer (PCa) currently represents the second most prevalent malignant neoplasia in men, representing 21% of all cancer cases. Benign Prostate Hyperplasia (BPH) is an illness prevailing in men above the age of 50, close to 90% after the age of 80. The prostate presents a high zinc concentration, about 10-fold higher than any other body tissue. In this work, samples of human prostate tissues with cancer, BPH and normal tissue were analyzed utilizing total reflection X-ray fluorescence spectroscopy using synchrotron radiation technique (SR-TXRF) to investigate the differences in the elemental concentrations in these tissues. SR-TXRF analyses were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, Sćo Paulo. It was possible to determine the concentrations of the following elements: P, S, K, Ca, Fe, Cu, Zn and Rb. By using Mann-Whitney U test it was observed that almost all elements presented concentrations with significant differences (?=0.05) between the groups studied.

Leitćo, R. G.; Palumbo, A.; Souza, P. A. V. R.; Pereira, G. R.; Canellas, C. G. L.; Anjos, M. J.; Nasciutti, L. E.; Lopes, R. T.

2014-02-01

409

THz pulses from 4th generation X-ray light sources: Perspectives for fully synchronized THz pump X-ray probe experiments  

SciTech Connect

In this paper the prospects of terahertz (THz) pulses generated at 4th generation X-ray light sources are presented on the example of recent results from a prototype set-up at the soft X-ray FEL FLASH. It is shown, that the THz pulses from the relativistic ultra short electron bunches have unique properties, that at FLASH are utilized for novel THz pump X-ray probe experiments with a robust few fs resolution. Based on these experiences it is discussed, how future facilities can benefit from implementation of similar or further improved instrumentation.

Gensch, M. [BESSY, Helmholtz-Center Berlin, Albert Einstein Str. 15, 12489 Berlin (Germany)

2010-02-03

410

Mapping of a particular element using an absorption edge with an X-ray fluorescence imaging microscope.  

PubMed

An X-ray fluorescence imaging microscope with a Wolter-type objective mirror (magnification: 13) has been constructed at beamline 39XU of SPring-8. Monochromatic X-rays (DeltaE/E approximately 10(-4)) in the energy range 6-10 keV were used for X-ray fluorescence excitation of the specimens. Using two monochromatic X-rays above and below the absorption edge of a particular element, a two-dimensional image of the element could be obtained. As a result, two-dimensional element mapping of the test specimens (Cu, Co, Ni, Fe and Ti wires) and constituent minerals (Fe, Mn and Ti) of a rock specimen (a piemontite-quartz schist) became possible. PMID:16609170

Yamamoto, K; Watanabe, N; Takeuchi, A; Takano, H; Aota, T; Fukuda, M; Aoki, S

2000-01-01

411

Natural speciation of Zn at the micrometer scale in a clayey soil using X-ray fluorescence, absorption, and diffraction  

Microsoft Academic Search

Combined use of synchrotron-based X-ray fluorescence (SXRF), diffraction (XRD), and absorption (EXAFS) with an X-ray spot size as small as five micrometers allows us to examine noninvasively heterogeneous soils and sediments. Specifically, the speciation of trace metals at low bulk concentrations and the nature of host minerals can be probed with a level of detail unattainable by other techniques. The

Alain Manceau; Matthew A. Marcus; Nobumichi Tamura; Olivier Proux; Nicolas Geoffroy; Bruno Lanson

2004-01-01

412

Shedding new light on historical metal samples using micro-focused synchrotron X-ray fluorescence and spectroscopy  

Microsoft Academic Search

Synchrotron-based micro-X-ray fluorescence (micro-XRF) and micro-X-ray absorption spectroscopy (micro-XAS) were used in the present study to obtain spatially resolved micro-scale information on elemental composition, trace element distribution, chemical speciation and oxidation state and\\/or mineral phase distribution within historical iron artefacts dating from the Iron Age to early Medieval Times. Large area two-dimensional trace element distribution maps and oxidation state maps

D. Grolimund; M. Senn; M. Trottmann; M. Janousch; I. Bonhoure; A. M. Scheidegger; M. A. Marcus

2004-01-01

413

Shedding new light on historical metal samples using micro-focused synchrotron X-ray fluorescence and spectroscopyB  

Microsoft Academic Search

Synchrotron-based micro-X-ray fluorescence (micro-XRF) and micro-X-ray absorption spectroscopy (micro-XAS) were used in the present study to obtain spatially resolved micro-scale information on elemental composition, trace element distribution, chemical speciation and oxidation state and\\/or mineral phase distribution within historical iron artefacts dating from the Iron Age to early Medieval Times. Large area two-dimensional trace element distribution maps and oxidation state maps

D. Grolimund; M. Senn; M. Trottmann; M. Janousch; A. M. Scheidegger; M. Marcus

414

In-Situ Parts-Per-Million Analysis of Marine Sediments by X-Ray Fluorescence Techniques  

Microsoft Academic Search

An energy-dispersive X-ray fluorescence analyser has been applied to the in-situ elemental analysis of marine and freshwater sediments. This technique allows upwards of 20 elements to be quantitatively measured to the 10 ppm level at water depths to 300 ft. The analyzer system consists of a solid cryogen-cooled Si(Li) X-ray detector with a 20 mil Be window, a 50 mCi109Cd

N. A. Wogman; K. K. Nielson

1976-01-01

415

Design of a pulsed X-ray system for fluorescent lifetime measurements with a timing accuracy of 109 ps  

Microsoft Academic Search

We describe the design of a table-top pulsed X-ray system for measuring fluorescent lifetime and wavelength spectra of samples in both crystal and powdered form. The novel element of the system is a light-excited X-ray tube with a tungsten anode at +30 kV potential. The S-20 photocathode is excited by a laser diode with a maximum rate of 10 MHz,

S. E. Derenzo; W. W. Moses; S. C. Blankespoor; M. Ito; K. Oba

1994-01-01

416

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

Microsoft Academic Search

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

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

2009-01-01

417

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

Microsoft Academic Search

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

N. Efe; S. Akman; P. Arikan

1987-01-01

418

X-ray absorption spectroscopy: A fluorescence detection system based on a plastic scintillator  

NASA Astrophysics Data System (ADS)

A fluorescence detection system based on a plastic scintillator is presented that can be used for both X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Its counting rate is limited by the pulsation frequency of the synchrotron radiation (3.16×10 6 counts s -1), and can be theoretically extended to roughly 5×10 7 counts s -1 if used on a multibunch storage ring synchrotron radiation source. Its physical characteristics (fluorescence decay time and fast electronics) are such that the dead-time correction is entirely defined by the revolution period of the charged particles in the storage ring. It shows a broad spectral response and is particularly well adapted to the measurement of hard X-rays (from 6 to 25 keV). Its volume is small (diameter 60 mm; height 240 mm), and filters of small dimensions are used to preferentially remove the scattered radiation. The entrance window of the detector is placed at 2-3 mm above the top of the sample, and a solid angle of collection of nearly 50% of 2? sr is achieved. The shape of the plastic scintillator can be easily modified to fit various geometries. It operates in both horizontal and vertical planes. It is about ten times less expensive than an energy-dispersive detection system based on a single Ge solid-state detector. The detector presents a high sensitivity. It is possible to obtain the entire EXAFS spectrum of an electrochemically (under potential deposition) deposited monolayer of Cu atoms on gold, with acquisition time of less than one hour (compared to 25 h for a Ge solid-state detector). Orientation-dependent X-ray absorption spectroscopy was performed on thin (800 Å) copper phthalocyanine film, and the spectra of diluted Cu 2+ ions in aqueous solution (18 ppm) and Co atoms in YBa 2Cu 3O 7 powder (230 ppm) were also measured to assess the sensitivity of the detector.

Tourillon, G.; Guay, D.; Lemonnier, M.; Bartol, F.; Badeyan, M.

1990-09-01

419

Apollo 16 geochemical X-ray fluorescene experiment: Preliminary report  

NASA Technical Reports Server (NTRS)

The lunar surface was mapped with respect to Mg, Al and Si as Al/Si and Mg/Si ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The Al/Si and Mg/Si chemical ratios correspond to those for anorthositic gabbro through gabbroic anorthosites or feldspathic basalts. The X-ray results suggest the occurrence of this premare crust, or material similar to it, at the Descartes landing site.

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

1972-01-01

420

Real-time studies of gallium adsorption and desorption kinetics on sapphire (0001) by grazing incidence small-angle x-ray scattering and x-ray fluorescence  

NASA Astrophysics Data System (ADS)

Gallium adsorption and desorption on c-plane sapphire has been studied by real-time grazing incidence small-angle x-ray scattering and x-ray fluorescence as a function of substrate temperature (680-740 °C) and Ga flux. The x-ray techniques monitor the surface morphology evolution and amount of Ga on the surface. During deposition, nanodroplets of liquid Ga are observed to form on the surface and coarsen. The growth of droplet size during continuous deposition follows dynamical scaling, in agreement with expectations from theory and simulations which include deposition-induced droplet coalescence. However, observation of continued droplet distance scale coarsening during desorption points to the necessity of including further physical processes in the modeling. The desorption rate at different substrate temperatures gives the activation energy of Ga desorption as 2.7 eV, comparable to measured activation energies for desorption from Ga droplets on other substrates and to the Ga heat of vaporization.

Wang, Yiyi; Özcan, Ahmet S.; Ludwig, Karl F.; Bhattacharyya, Anirban

2008-05-01

421

Direct spectral recovery using X-ray fluorescence measurements for material decomposition applications using photon counting spectral X-ray detectors  

NASA Astrophysics Data System (ADS)

We present investigations into direct, calibration-free recovery of distorted spectral x-ray measurements with the Medipix 2 detector. Spectral x-ray measurements using pixelated photon counting spectral x-ray detectors are subject to significant spectral distortion. For detectors with small pixel size, charge sharing between adjacent electrodes often dominates this distortion. In material decomposition applications, a popular spectral recovery technique employs a calibration phantom with known spectral properties. This works due to the similarity of the attenuation properties of the phantom and the material to be studied. However, this approach may be too simplistic for clinical imaging applications as it assumes the homogeneity (and knowledge) of exactly the properties whose variation accounts entirely for the diagnostic content of the spectral data obtained by the photon counting detector. It may also be difficult to find the right calibration phantom for varying patient size and tissue densities on a case-by-case basis. Thus, it is desirable to develop direct correction strategies, based on the objectively measurable response of the detector. We model analytically the distortion of a spectral signal in a PCSXD by applying Gaussian broadening and a charge-sharing model. The model parameters are fitted to the measured fluorescence of several metals. While we are investigating the methodology using Medipix detectors, it should be applicable to other PCXDs as well.

Campbell-Ricketts, Tom; Das, Mini

2014-03-01

422

In-flight Performance of the High Energy X-ray Timing Experiment on the Rossi X-ray Timing Explorer  

Microsoft Academic Search

The High Energy X-ray Timing Experiment (HEXTE) is one of three scientific\\u000ainstruments aboard the Rossi X-ray Timing Explorer (RXTE), which was launched\\u000aon December 30, 1995. RXTE performs timing and spectral studies of bright x-ray\\u000asources to determine the physical parameters of these systems. The HEXTE\\u000aconsists of two independent clusters of detectors, each cluster containing four\\u000aNaI(Tl)\\/CsI(Na) phoswich

P. L. HINK; P. R. Blanco; D. E. Gruber; W. A. Heindl; D. R. MacDonald; D. C. Marsden; M. R. Pelling; L. R. Wayne

1997-01-01

423

Inorganic chemical investigation by x-ray fluorescence analysis: The Viking Mars Lander  

USGS Publications Warehouse

The inorganic chemical investigation added in August 1972 to the Viking Lander scientific package will utilize an energy-dispersive X-ray fluorescence spectrometer in which four sealed, gas-filled proportional counters will detect X-rays emitted from samples of the Martian surface materials irradiated by X-rays from radioisotope sources (55Fe and 109Cd). The output of the proportional counters will be subjected to pulse-height analysis by an on-board step-scanning single-channel analyzer with adjustable counting periods. The data will be returned to Earth, via the Viking Orbiter relay system, and the spectra constructed, calibrated, and interpreted here. The instrument is inside the Lander body, and samples are to be delivered to it by the Viking Lander Surface Sampler. Calibration standards are an integral part of the instrument. The results of the investigation will characterize the surface materials of Mars as to elemental composition with accuracies ranging from a few tens of parts per million (at the trace-element level) to a few percent (for major elements) depending on the element in question. Elements of atomic number 11 or less are determined only as a group, though useful estimates of their individual abundances maybe achieved by indirect means. The expected radiation environment will not seriously hamper the measurements. Based on the results, inferences can be drawn regarding (1) the surface mineralogy and lithology; (2) the nature of weathering processes, past and present, and the question of equilibrium between the atmosphere and the surface; and (3) the extent and type of differentiation that the planet has undergone. The Inorganic Chemical Investigation supports and is supported by most other Viking Science investigations. ?? 1973.

Toulmin, III, P.; Baird, A. K.; Clark, B. C.; Keil, K.; Rose, Jr. , H. J.

1973-01-01

424

Simulated 'On-Line' Wear Metal Analysis of Lubricating Oils by X-Ray Fluorescence Spectroscopy  

NASA Technical Reports Server (NTRS)

The objective of this project was to assess the sensitivity of X-ray Fluorescence Spectroscopy (XFS) for quantitative evaluation of metal particle content in engine oil suspensions and the feasibility of real-time, dynamic wear metal analysis. The study was focused on iron as the majority wear metal component. Variable parameters were: particle size, particle concentration and oil velocity. A commercial XFS spectrometer equipped with interchangeable static/dynamic (flow cell) sample chambers was used. XFS spectra were recorded for solutions of Fe-organometallic standard and for a series of DTE oil suspensions of high purity spherical iron particles of 2g, 4g, and 8g diameter, at concentrations from 5 ppm to 5,000 ppm. Real contaminated oil samples from Langley Air Force Base aircraft engines and NASA Langley Research Center wind tunnels were also analyzed. The experimental data conform the reliability of XFS as the analytical method of choice for this project. Intrinsic inadequacies of the instrument for precise analytic work at low metal concentrations were identified as being related to the particular x-ray beam definition, system geometry, and flow-cell materials selection. This work supports a proposal for the design, construction and testing of a conceptually new, miniature XFS spectrometer with superior performance, dedicated to on-line, real-time monitoring of lubricating oils in operating engines. Innovative design solutions include focalization of the incident x-ray beam, non-metal sample chamber, and miniaturization of the overall assembly. The instrument would contribute to prevention of catastrophic engine failures. A proposal for two-year funding has been presented to NASA Langley Research Center Internal Operation Group (IOG) Management, to continue the effort begun by this summer's project.

Kelliher, Warren C.; Partos, Richard D.; Nelson, Irina

1996-01-01

425

C-library raft : Reconstruction algorithms for tomography. Applications to X-ray fluorescence tomography  

NASA Astrophysics Data System (ADS)

There are many reconstruction algorithms for tomography, raft for short, and some of them are considered "classic" by researchers. The so-called raft library, provide a set of useful and basic tools, usually needed in many inverse problems that are related to medical imaging. The subroutines in raft are free software and written in C language; portable to any system with a working C compiler. This paper presents source codes written according to raft routines, applied to a new imaging modality called X-ray fluorescence tomography. Program summaryProgram title: raft Catalogue identifier: AEJY_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJY_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence, version 2 No. of lines in distributed program, including test data, etc.: 218 844 No. of bytes in distributed program, including test data, etc.: 3 562 902 Distribution format: tar.gz Programming language: Standard C. Computer: Any with a standard C compiler Operating system: Linux and Windows Classification: 2.4, 2.9, 3, 4.3, 4.7 External routines: raft: autoconf 2.60 or later - http://www.gnu.org/software/autoconf/ GSL scientific library - http://www.gnu.org/software/gsl/ Confuse parser library - http://www.nongnu.org/confuse/ raft-fun: gengetopt - http://www.gnu.org/software/gengetopt/gengetopt.html Nature of problem: Reconstruction algorithms for tomography, specially in X-ray fluorescence tomography. Solution method: As a library, raft covers the standard reconstruction algorithms like filtered backprojection, Novikov's inversion, Hogan's formula, among others. The input data set is represented by a complete sinogram covering a determined angular range. Users are allowed to set solid angle range for fluorescence emission at each algorithm. Running time: 1 second to 15 minutes, depending on the data size.

Miqueles, Eduardo X.; De Pierro, Alvaro R.

2011-12-01

426

Application of imaging plates to x-ray imaging and spectroscopy in laser plasma experiments (invited)  

SciTech Connect

We report recent progress in x-ray diagnosis of laser-plasma experiments using imaging plates. Imaging plates are photostimulable phosphor screens [BaF(Br0.85,I0.15):Eu{sup 2+}] deposited on flexible metal or plastic substrates. We applied imaging plates to x-ray microscopy of inertial confinement fusion experiments. Self-emission x-ray images of imploded cores were obtained successfully with high-magnification, target-mounted pinholes using imaging plates as detectors. Imaging plates were also used in ultraintense laser experiments at the Rutherford Appleton Laboratory, where small samarium foils were irradiated by high intensity laser pulses from the Vulcan laser system. K-shell x rays from the foil ({approx}40 keV) were used as a line x-ray source for one-dimensional microscopic radiography, and the performance of imaging plates on high-energy x-ray backlit radiography experiments was demonstrated by imaging sinusoidal grooves of 6 {mu}m amplitude on a Au foil. Detailed K-shell spectra from Cu targets were also obtained by coupling an imaging plate with a highly ordered pyrolytic graphite crystal spectrometer. The performance of the imaging plates as evaluated in actual laser plasma experiments is presented.

Izumi, N.; Snavely, R.; Gregori, G.; Koch, J. A.; Park, H.-S.; Remington, B. A. [University of California, Lawrence Livermore National Laboratory, P.O. Box 808, L-481, Livermore, California 94550 (United States)

2006-10-15

427

Electrochemical X-ray fluorescence spectroscopy for trace heavy metal analysis: enhancing X-ray fluorescence detection capabilities by four orders of magnitude.  

PubMed

The development of a novel analytical technique, electrochemical X-ray fluorescence (EC-XRF), is described and applied to the quantitative detection of heavy metals in solution, achieving sub-ppb limits of detection (LOD). In EC-XRF, electrochemical preconcentration of a species of interest onto the target electrode is achieved here by cathodic electrodeposition. Unambiguous elemental identification and quantification of metal concentration is then made using XRF. This simple electrochemical preconcentration step improves the LOD of energy dispersive XRF by over 4 orders of magnitude (for similar sample preparation time scales). Large area free-standing boron doped diamond grown using microwave plasma chemical vapor deposition techniques is found to be ideal as the electrode material for both electrodeposition and XRF due to its wide solvent window, transparency to the XRF beam, and ability to be produced in mechanically robust freestanding thin film form. During electrodeposition it is possible to vary both the deposition potential (Edep) and deposition time (tdep). For the metals Cu(2+) and Pb(2+) the highest detection sensitivities were found for Edep = -1.75 V and tdep (=) 4000 s with LODs of 0.05 and 0.04 ppb achieved, respectively. In mixed Cu(2+)/Pb(2+) solutions, EC-XRF shows that Cu(2+) deposition is unimpeded by Pb(2+), across a broad concentration range, but this is only true for Pb(2+) when both metals are present at low concentrations (10 nM), boding well for trace level measurements. In a dual mixed metal solution, EC-XRF can also be employed to either selectively deposit the metal which has the most positive formal reduction potential, E(0), or exhaustively deplete it from solution, enabling uninhibited detection of the metal with the more negative E(0). PMID:24701959

Hutton, Laura A; O'Neil, Glen D; Read, Tania L; Ayres, Zoė J; Newton, Mark E; Macpherson, Julie V

2014-05-01

428

Post-Shot Simulations of NIC Experiments with Comparison to X-ray Measurements  

NASA Astrophysics Data System (ADS)

National Ignition Campaign experiments at NIF are ongoing and post-shot simulations play an important role in understanding the physical processes occurring in the quest for demonstrating fusion burn. In particular, it is important to understand the x-ray environment inside the hohlraum targets, which is studied using various x-ray diagnostics. The Dante instrument measures the time dependent x-ray emission escaping out of the hohlraum laser entrance holes (LEHs) and the SXI instrument provides a time-integrated image of both soft and hard x-rays. We compare calculated total x-ray emission with Dante data as well as the relative high energy Mband emission that contributes to capsule preheat. We correct our calculated x-ray emission to account for differences between simulation and data on LEH closure using SXI data. We provide results for both ``standard candle'' simulation with no added multipliers and for simulations with time-dependent multipliers that are used to obtain agreement with shock timing and implosion velocity data. The physics justification for the use of multipliers is to account for potential missing energy or incorrect ablation modeling. The relative importance of these two effects can be studied through comparison of post-shot simulations with x-ray measurements.

Eder, David; Jones, Oggie; Suter, Larry; Moore, Alastair; Schneider, Marilyn

2012-10-01

429

Search for X-rays and relativistic electrons in laboratory discharge experiments  

NASA Astrophysics Data System (ADS)

In 2013 discharge experiments were carried out at the Technical University of Eindhoven. The experimental set-up was designed to search for both X-rays and electrons produced in meter-scale sparks using a 1 MV Marx generator. In this paper we present the spatial distribution of signals and examine whether they are X-rays only or X-rays and electrons. Other characteristics of the signals will be presented as well. These experiments are carried out in the context of a larger effort to understand the various phenomena of X-rays and gammas from natural lightning. We acknowledge Z. Scherrer, K. Weber and K. LeCaptain at the Carthage college for supporting the initial data-analysis.

Ostgaard, Nikolai; Carlson, Brant E.; Grųndahl, Ųystein; Kochkin, Pavlo; Nisi, Ragnhild S.; Gjesteland, Thomas

2014-05-01

430

Lithographically-fabricated channel arrays for confocal x-ray fluorescence microscopy and XAFS  

NASA Astrophysics Data System (ADS)

Confocal X-ray Fluorescence Microscopy (CXRF) employs overlapping focal regions of two x-ray optics—a condenser and collector—to directly probe a 3D volume. The minimum-achievable size of this probe volume is limited by the collector, for which polycapillaries are generally the optic of choice. Recently, we demonstrated an alternative collection optic for CXRF, consisting of an array of micron-scale collimating channels, etched in silicon, and arranged like spokes of a wheel directed towards a single source position. The optic, while successful, had a working distance of only 0.2 mm and exhibited relatively low total collection efficiency, limiting its practical application. Here, we describe a new design in which the collimating channels are formed by a staggered array of pillars whose side-walls taper away from the channel axis. This approach improves both collection efficiency and working distance, while maintaining excellent spatial resolution. We illustrate these improvements with confocal XRF data obtained at the Cornell High Energy Synchrotron Source (CHESS) and the Advanced Photon Source (APS) beamline 20-ID-B.

Woll, Arthur R.; Agyeman-Budu, David; Choudhury, Sanjukta; Coulthard, Ian; Finnefrock, Adam C.; Gordon, Robert; Hallin, Emil; Mass, Jennifer

2014-03-01

431

Surface elemental analysis in ambient atmosphere using electron-induced x-ray fluorescence  

SciTech Connect

The progress in the development of the atmospheric electron x-ray spectrometer (AEXS) is described. The AEXS is a surface analysis tool based on excitation of characteristic x-ray fluorescence (XRF) spectra from samples in ambient atmospheres using a focused electron beam. Operation in ambient atmospheres with moderate-to-high spatial resolution in comparison to similar instruments is obtained through the use of a thin electron-transmissive membrane to isolate the vacuum of the electron probe, obviating the need for the samples to be drawn into the probe vacuum. Our initial setup that was used for the demonstration of the ability of the transmitted electrons to excite the XRF spectra in the external atmosphere consisted of an actively pumped chamber from within which the electrons were transmitted--not a portable instrument. The AEXS instrument that has been assembled in our laboratory during the past year consists of a miniature 20 keV electron microprobe that is vacuum sealed with a thin SiN membrane and requires no active pumping--a big step towards the development of a stand-alone instrument. The microprobe has been in operation for over one year and is used for performing rapid elemental analysis of NIST and USGS traceable metal and mineral standards, with good agreement with the certified composition for samples in up to about 90 Torr cm thick external atmospheres.

Urgiles, Eduardo; Toda, Risaku; Wilcox, Jaroslava Z. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91109 (United States)

2006-01-15

432

Region of interest reconstruction in x-ray fluorescence computed tomography for negligible attenuation  

PubMed Central

X-ray fluorescence computed tomography (XFCT) is a synchrotron-based imaging modality employed for mapping the distribution of elements within slices or volumes of intact specimens. A pencil beam of external radiation is used to stimulate emission of characteristic X-rays from within a sample, which is scanned and rotated through the pencil beam in a first-generation tomographic geometry. One limitation of XFCT is the long image acquisition time required to acquire a complete set of line integrals one-by-one. Typically, even if only a portion of a slice through the object is of interest, measurement lines are acquired spanning the entire object at every projection view over 180 degrees to avoid reconstructing images with so-called truncation artifacts. In this work, we show that when attenuation is negligible, recent developments in tomographic reconstruction theory can be used to reduce the scanning effort required to reconstruct regions of interest within the slice. The new theory provides explicit guidance as to which line integrals must be measured for a given ROI and also provides a backprojection-filtration reconstruction algorithm that averts the truncation artifacts that typically plague filtered backprojection reconstructions from truncated data. This is demonstrated through simulation studies and with real synchrotron-based XFCT data.

La Riviere, Patrick; Vargas, Phillip; Xia, Dan; Pan, Xiaochuan

2010-01-01

433

A multi-channel monolithic Ge detector system for fluorescence x-ray absorption spectroscopy  

SciTech Connect

Construction and performance of a monolithic quad-pixel Ge detector for fluorescence x-ray absorption spectroscopy (XAS) at synchrotron radiation sources are described. The detector semiconductor element has an active surface area of 4.0 cm{sup 2} which is electrically separated into four 1.0 cm{sup 2} pixels, with little interfacial dead volume. Spatial response of the array shows that cross-talk between adjacent pixels is < 10% for 5.9 keV photons that fall within 0.5 mm of the pixel boundaries. The detector electronics system uses pre-amplifiers built at LBNL with commercial Tennelec Model TC 244 amplifiers. Using an {sup 55}Fe test source (MnK{sub {alpha}}, 5.9 keV), energy resolution of better than 200 eV is achieved with a 4 {mu}sec peaking time. At 0.5 {mu}sec peaking time, pulse pileup results in a 75% throughput efficiency for an incoming count rate of 100 kHz. Initial XAS fluoresncece measurements at the beamline 4 wiggler end stations at SSRL show that the detector system has several advantages over commercial x-ray spectrometers for low-concentration counting.

Bucher, J.J.; Allen, P.G.; Edelstein, N.M.; Shuh, D.K. [Lawrence Berkeley National Lab., CA (United States). Chemical Sciences Div.; Madden, N.W.; Cork, C.; Luke, P.; Pehl, D.; Malone, D. [Lawrence Berkeley National Lab., CA (United States). Engineering Div.

1995-03-01

434

X-ray cell tracking: from ex-vivo to in-vivo experiments  

NASA Astrophysics Data System (ADS)

The capacity to track cells (cell tracking) using x-rays on ex-vivo specimens of both malignant and non-malignant cell lines on small animals has been demonstrated recently. Gold nanoparticles have been used as a cellular contrast agent to render cells visible in x-ray microCT acquisitions. The limits of the technique proposed are basically driven by the imaging system used. Single cell resolution can be achieved using synchrotron radiation in-vitro or ex-vivo samples. Micro-focus x-ray tubes can be used to obtain high resolution cell tracking but with some limitations. However, the translation from ex-vivo to in-vivo experiments is not straightforward. The dose restrictions required for in-vivo longitudinal experiments set severe limitations on the technique. Here we present a detailed investigation showing a significant reduction of x-ray dose for the tracking of brain tumour cells. Monte Carlo simulations have been performed considering different spatial resolutions, photon fluence, number of projections, lesion dimension and cell contrast dilution. The findings are compared with real samples imaged using the same parameters. A pioneering in-vivo experiment conducted at the SYRMEP beamline (Elettra, Basovizza, Italy) is presented here as proof of principle of in-vivo longitudinal x-ray cell tracking experiments on small animals at low x-ray doses.

Astolfo, A.; Schültke, E.; Menk, R.-H.; Hall, C.; Juurlink, B.; Arfelli, F.

2013-06-01

435

X-ray fluoresced high-Z (up to Z=82) K x rays produced by LiNbO3 and LiTaO3 pyroelectric crystal electron accelerators  

NASA Astrophysics Data System (ADS)

High-energy bremsstrahlung and K x rays were used to produce nearly background-free K x-ray spectra of up to 87 keV (Pb) via x-ray fluorescence. The fluorescing radiation was produced by electron accelerators, consisting of heated and cooled cylindrical LiTaO3 and LiNbO3 crystals at mTorr pressures. The process of gas amplification whereby the ambient gas pressure is optimized to maximize the electron energy was used to produce energetic electrons which when incident on a W/Bi target, gave rise to a radiation field consisting of high-energy bremsstrahlung as well as W and Bi K x rays. These photons were used to fluoresce Ta and Pb K x rays.

Brownridge, James D.; Shafroth, Stephen M.

2004-08-01

436

Simulation Study of Quantitative X-Ray Fluorescence Analysis of Ore Slurry Using Partial Least-Squares Regression  

NASA Astrophysics Data System (ADS)

X-ray fluorescence (XRF) in combination with partial least-squares (PLS) regression was employed to analyze the ore slurry grade. Using the Monte Carlo simulation code PENELOPE, X-ray fluorescence spectra of ore samples were obtained. Good accuracy was achieved when this method was used to analyze elements with concentrations of several percent or above. It was demonstrated that the more the number of X-ray fluorescence spectra used to calibrate, the better the obtained accuracy. In this method detector resolution was found to have little or no effect on the results of quantitative analysis. The effect of the concentration of water was investigated as well, and it was found to have little influence on the results.

Lin, Caishou; Mao, Li; Huang, Ning; An, Zhu

2012-05-01

437

Optimizing the operation of a high resolution vertical Johann spectrometer using a high energy fluorescer x-ray source  

NASA Astrophysics Data System (ADS)

This paper describes the operation and testing for a vertical Johann spectrometer (VJS) operating in the 13 keV range. The spectrometer is designed to use thin curved mica crystals or thick germanium crystals. The VJS must have a resolution of E/?E=3000 or better to measure the Doppler broadening of highly ionized krypton and operate at a small x-ray angle in order to be used as a diagnostic in a laser plasma target chamber. The VJS was aligned, tested, and optimized using a fluorescer type high energy x-ray (HEX) source located at National Security Technologies (NSTec), LLC, in Livermore, CA. The HEX uses a 160 kV x-ray tube to excite fluorescence from various targets. Both rubidium and bismuth fluorescers were used for this effort. This presentation describes the NSTec HEX system and the methods used to optimize and characterize the VJS performance.

Haugh, Michael; Stewart, Richard

2010-10-01

438

Optimizing the operation of a high resolution vertical Johann spectrometer using a high energy fluorescer x-ray source.  

PubMed

This paper describes the operation and testing for a vertical Johann spectrometer (VJS) operating in the 13 keV range. The spectrometer is designed to use thin curved mica crystals or thick germanium crystals. The VJS must have a resolution of E/?E=3000 or better to measure the Doppler broadening of highly ionized krypton and operate at a small x-ray angle in order to be used as a diagnostic in a laser plasma target chamber. The VJS was aligned, tested, and optimized using a fluorescer type high energy x-ray (HEX) source located at National Security Technologies (NSTec), LLC, in Livermore, CA. The HEX uses a 160 kV x-ray tube to excite fluorescence from various targets. Both rubidium and bismuth fluorescers were used for this effort. This presentation describes the NSTec HEX system and the methods used to optimize and characterize the VJS performance. PMID:21034064

Haugh, Michael; Stewart, Richard

2010-10-01

439

Experimental demonstration of direct L-shell x-ray fluorescence imaging of gold nanoparticles using a benchtop x-ray source  

PubMed Central

Purpose: To develop a proof-of-principle L-shell x-ray fluorescence (XRF) imaging system that locates and quantifies sparse concentrations of gold nanoparticles (GNPs) using a benchtop polychromatic x-ray source and a silicon (Si)-PIN diode x-ray detector system. Methods: 12-mm-diameter water-filled cylindrical tubes with GNP concentrations of 20, 10, 5, 0.5, 0.05, 0.005, and 0 mg/cm3 served as calibration phantoms. An imaging phantom was created using the same cylindrical tube but filled with tissue-equivalent gel containing structures mimicking a GNP-loaded blood vessel and approximately 1 cm3 tumor. Phantoms were irradiated by a 3-mm-diameter pencil-beam of 62 kVp x-rays filtered by 1 mm aluminum. Fluorescence/scatter photons from phantoms were detected at 90° with respect to the beam direction using a Si-PIN detector placed behind a 2.5-mm-diameter lead collimator. The imaging phantom was translated horizontally and vertically in 0.3-mm steps to image a 6 mm × 15 mm region of interest (ROI). For each phantom, the net L-shell XRF signal from GNPs was extracted from background, and then corrected for detection efficiency and in-phantom attenuation using a fluorescence-to-scatter normalization algorithm. Results: XRF measurements with calibration phantoms provided a calibration curve showing a linear relationship between corrected XRF signal and GNP mass per imaged voxel. Using the calibration curve, the detection limit (at the 95% confidence level) of the current experimental setup was estimated to be a GNP mass of 0.35 ?g per imaged voxel (1.73 × 10?2 cm3). A 2D XRF map of the ROI was also successfully generated, reasonably matching the known spatial distribution as well as showing the local variation of GNP concentrations. Conclusions:L-shell XRF imaging can be a highly sensitive tool that has the capability of simultaneously imaging the spatial distribution and determining the local concentration of GNPs presented on the order of parts-per-million level within subcentimeter-sized ex vivo samples and superficial tumors during preclinical animal studies.

Manohar, Nivedh; Reynoso, Francisco J.; Cho, Sang Hyun

2013-01-01

440

Experimental demonstration of direct L-shell x-ray fluorescence imaging of gold nanoparticles using a benchtop x-ray source  

SciTech Connect

Purpose: To develop a proof-of-principle L-shell x-ray fluorescence (XRF) imaging system that locates and quantifies sparse concentrations of gold nanoparticles (GNPs) using a benchtop polychromatic x-ray source and a silicon (Si)-PIN diode x-ray detector system.Methods: 12-mm-diameter water-filled cylindrical tubes with GNP concentrations of 20, 10, 5, 0.5, 0.05, 0.005, and 0 mg/cm{sup 3} served as calibration phantoms. An imaging phantom was created using the same cylindrical tube but filled with tissue-equivalent gel containing structures mimicking a GNP-loaded blood vessel and approximately 1 cm{sup 3} tumor. Phantoms were irradiated by a 3-mm-diameter pencil-beam of 62 kVp x-rays filtered by 1 mm aluminum. Fluorescence/scatter photons from phantoms were detected at 90° with respect to the beam direction using a Si-PIN detector placed behind a 2.5-mm-diameter lead collimator. The imaging phantom was translated horizontally and vertically in 0.3-mm steps to image a 6 mm × 15 mm region of interest (ROI). For each phantom, the net L-shell XRF signal from GNPs was extracted from background, and then corrected for detection efficiency and in-phantom attenuation using a fluorescence-to-scatter normalization algorithm.Results: XRF measurements with calibration phantoms provided a calibration curve showing a linear relationship between corrected XRF signal and GNP mass per imaged voxel. Using the calibration curve, the detection limit (at the 95% confidence level) of the current experimental setup was estimated to be a GNP mass of 0.35 ?g per imaged voxel (1.73 × 10{sup ?2} cm{sup 3}). A 2D XRF map of the ROI was also successfully generated, reasonably matching the known spatial distribution as well as showing the local variation of GNP concentrations.Conclusions: L-shell XRF imaging can be a highly sensitive tool that has the capability of simultaneously imaging the spatial distribution and determining the local concentration of GNPs presented on the order of parts-per-million level within subcentimeter-sized ex vivo samples and superficial tumors during preclinical animal studies.

Manohar, Nivedh; Reynoso, Francisco J.; Cho, Sang Hyun [Nuclear/Radiological Engineering and Medical Physics Programs, Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States)] [Nuclear/Radiological Engineering and Medical Physics Programs, Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States)

2013-08-15

441

Development of miniature detector for soft x-ray used in laser plasma interaction experiments  

Microsoft Academic Search

The miniature soft X-ray detector (M-XRD) is the key part of the miniature soft X-ray spectrometer, which was developed and used in laser-produced plasma interaction experiments on Shenguang III Laser Facility. The results of the analyze shown that the significant schemes was to get well-proportioned electric field distributions, which can obtain the strongest intensity of electric field, by using the

Zhan-Ping Wang; Xiao-Hong Tang; Rong-Qing Yi; Qi-Ming Sun; Chun-Ming Gao; Ying Zhou; Li-Feng Yang; Ya-Fei Wang

2008-01-01

442

Z-Pinch-Generated X Rays Demonstrate Potential for Indirect-Drive ICF Experiments  

Microsoft Academic Search

Hohlraums measuring 6 mm in diameter by 7 mm in height have been heated by x rays from a Z pinch. Over the measured x-ray input powers P of 0.7 to 13 TW, the hohlraum radiation temperature T increases from ~55 to ~130 eV, and is in agreement with the Planckian relation T~P1\\/4. The results suggest that indirect-drive inertial-confinement-fusion experiments

T. W. L. Sanford; R. E. Olson; R. L. Bowers; G. A. Chandler; M. S. Derzon; D. E. Hebron; R. J. Leeper; R. C. Mock; T. J. Nash; D. L. Peterson; L. E. Ruggles; W. W. Simpson; K. W. Struve; R. A. Vesey

1999-01-01