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1

Student X-Ray Fluorescence Experiments  

ERIC Educational Resources Information Center

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

Fetzer, Homer D.; And Others

1975-01-01

2

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

3

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

4

Imaging x-ray fluorescence relevant to hydrodynamic mixing experiments at the National Ignition Facility  

NASA Astrophysics Data System (ADS)

The National Ignition Facility (NIF) is capable of providing enough energy to explore areas of physics that are not possible on any previous laser system. This includes large-volume, geometrically complex hydrodynamic and radiation hydrodynamic experiments in which traditional, line-integrated radiographic techniques limit the quality of the results. As an example, we are involved in divergent hydrodynamic experiments at the NIF, motivated by supernova hydrodynamics, that cannot be diagnosed in detail with transmission radiography. X-ray scattering has been considered for this purpose and appears feasible [1]. Here we consider fluorescence imaging, a better candidate as the cross section of photoabsorption in the several-keV range is roughly 100 times larger than that of scattering. A single layer of the target will be uniformly doped with a fluorescent tracer, which will be pumped by a sheet of x-rays. The fluorescent intensity will be measured to create a density map of the doped material as it mixes with other layers. Developing this diagnostic will create a powerful tool to characterize hydrodynamic experiments with complex geometries.[4pt] [1] Huntington et al. High Energy Density Physics 6, 194 (2010).

MacDonald, Michael; Gamboa, Eliseo; Kuranz, Carolyn; Keiter, Paul; Drake, R. Paul

2012-10-01

5

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

6

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

7

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

8

The Viking X ray fluorescence experiment - Analytical methods and early results  

NASA Technical Reports Server (NTRS)

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 gain drift adjustments, subtraction of background components, and use of a mathematical response model with adjustable parameters set by prelaunch measurements on selected rock standards. Bulk fines at both Viking landing sites are quite similar in composition, implying that a chemically and mineralogically homogeneous regolith covers much of the surface of the planet. Important differences between samples include a higher sulfur content in what appear to be duricrust fragments than in fines and a lower iron content in fines taken from beneath large rocks than those taken from unprotected surface material. Further extensive reduction of these data will allow more precise and more accurate analytical numbers to be determined and thus a more comprehensive understanding of elemental trends between samples.

Clark, B. C., III; Castro, A. J.; Rowe, C. D.; Baird, A. K.; Rose, H. J., Jr.; Toulmin, P., III; Christian, R. P.; Kelliher, W. C.; Keil, K.; Huss, G. R.

1977-01-01

9

Coded Aperture Imaging for Fluorescent X-rays-Biomedical Applications  

SciTech Connect

Employing a coded aperture pattern in front of a charge couple device pixilated detector (CCD) allows for imaging of fluorescent x-rays (6-25KeV) being emitted from samples irradiated with x-rays. Coded apertures encode the angular direction of x-rays and allow for a large Numerical Aperture x- ray imaging system. The algorithm to develop the self-supported coded aperture pattern of the Non Two Holes Touching (NTHT) pattern was developed. The algorithms to reconstruct the x-ray image from the encoded pattern recorded were developed by means of modeling and confirmed by experiments. Samples were irradiated by monochromatic synchrotron x-ray radiation, and fluorescent x-rays from several different test metal samples were imaged through the newly developed coded aperture imaging system. By choice of the exciting energy the different metals were speciated.

Haboub, Abdel; MacDowell, Alastair; Marchesini, Stefano; Parkinson, Dilworth

2013-06-01

10

Coded aperture imaging for fluorescent x-rays  

SciTech Connect

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. [Lawrence Berkeley National Laboratories, Berkeley, California 94720 (United States); Lincoln University, Life and Physical Sciences Department, Jefferson City, Missouri 65101 (United States); MacDowell, A. A.; Marchesini, S.; Parkinson, D. Y. [Lawrence Berkeley National Laboratories, Berkeley, California 94720 (United States)

2014-06-15

11

X-ray fluorescence with synchrotron radiation  

SciTech Connect

X-ray fluorescence (XRF) has long been used to make measurements of trace element concentrations in biological materials with very high sensitivity. It has not been previously possible to work with micrometer spatial resolutions because of the relatively low brightness of x-ray tubes. This situation is much improved by using synchrotron storage ring x-ray sources since the brightness of the synchrotron source is many orders of magnitude higher than is obtained with the most intense tube sources. These intense sources open the possibility of using the XRF technique for measurements with resolutions of approximately cellular dimensions. A description of a current research project at Brookhaven which uses synchrotron radiation induced x-ray emission (SRIXE) is presented to illustrate a specific application of the method in biology. 1 ref., 4 figs.

Jones, K.W.; Gordon, B.M.; Hanson, A.L.; Pounds, J.G.; Schidlovsky, G.

1986-03-01

12

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

13

Simulation of x-ray fluorescence spectra  

SciTech Connect

A method for simulating x-ray fluorescence (XRF) spectra in hybrid densitometry is presented. This technique allows simulation of XRF spectra for solutions with arbitrary concentrations of special nuclear material and minor actinides excited by an x-ray generator. Spectra for mixed uranium and plutonium solutions with U/Pu ratios ranging from 100 to 1 have been generated. This range of ratios applies to most solutions found in plutonium reprocessing plants. XRF simulation can provide important data for estimating instrument precision, evaluating analysis techniques, and training system operators. Applications of XRF simulation in the development of the Los Alamos Hybrid K-Edge/XRF Densitometer system are described.

Collins, M.L.; Hsue, S.T. [Los Alamos National Lab., NM (United States); Gunnink, R. [Gunnink (R.), Fremont, CA (United States)

1996-09-01

14

Surface-Enhanced X-Ray Fluorescence  

NASA Technical Reports Server (NTRS)

Surface-enhanced x-ray fluorescence (SEn-XRF) spectroscopy is a form of surface- enhanced spectroscopy that was conceived as a means of obtaining greater sensitivity in x-ray fluorescence (XRF) spectroscopy. As such, SEn-XRF spectroscopy joins the ranks of such other, longer-wavelength surface-enhanced spectroscopies as those based on surface-enhanced Raman scattering (SERS), surface-enhanced resonance Raman scattering (SERRS), and surfaceenhanced infrared Raman absorption (SEIRA), which have been described in previous NASA Tech Briefs articles. XRF spectroscopy has been used in analytical chemistry for determining the elemental compositions of small samples. XRF spectroscopy is rapid and quantitative and has been applied to a variety of metal and mineralogical samples. The main drawback of XRF spectroscopy as practiced heretofore is that sensitivity has not been as high as required for some applications. In SEn-XRF as in the other surface-enhanced spectroscopies, one exploits several interacting near-field phenomena, occurring on nanotextured surfaces, that give rise to local concentrations of incident far-field illumination. In this case, the far-field illumination comes from an x-ray source. Depending on the chemical composition and the geometry of a given nanotextured surface, these phenomena could include the lightning-rod effect (concentration of electric fields at the sharpest points on needlelike surface features), surface plasmon resonances, and grazing incidence geometric effects. In the far field, the observable effect of these phenomena is an increase in the intensity of the spectrum of interest - in this case, the x-ray fluorescence spectrum of chemical elements of interest that may be present within a surface layer at distances no more than a few nanometers from the surface.

Anderson, Mark

2010-01-01

15

Preliminary results from the Viking X-ray fluorescence experiment - The first sample from Chryse Planitia, Mars  

NASA Technical Reports Server (NTRS)

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's 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 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 plus or minus 2; Ti, less than 1; S, 2 to 5; the Ca/K ratio by weight is greater than 5.

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

1976-01-01

16

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

1976-01-01

17

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

18

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

19

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

20

Proton-induced x-ray fluorescence CT imaging  

PubMed Central

Purpose: To demonstrate the feasibility of proton-induced x-ray fluorescence CT (pXFCT) imaging of gold in a small animal sized object by means of experiments and Monte Carlo (MC) simulations. Methods: First, proton-induced gold x-ray fluorescence (pXRF) was measured as a function of gold concentration. Vials of 2.2 cm in diameter filled with 0%–5% Au solutions were irradiated with a 220 MeV proton beam and x-ray fluorescence induced by the interaction of protons, and Au was detected with a 3 × 3 mm2 CdTe detector placed at 90° with respect to the incident proton beam at a distance of 45 cm from the vials. Second, a 7-cm diameter water phantom containing three 2.2-diameter vials with 3%–5% Au solutions was imaged with a 7-mm FWHM 220 MeV proton beam in a first generation CT scanning geometry. X-rays scattered perpendicular to the incident proton beam were acquired with the CdTe detector placed at 45 cm from the phantom positioned on a translation/rotation stage. Twenty one translational steps spaced by 3 mm at each of 36 projection angles spaced by 10° were acquired, and pXFCT images of the phantom were reconstructed with filtered back projection. A simplified geometry of the experimental data acquisition setup was modeled with the MC TOPAS code, and simulation results were compared to the experimental data. Results: A linear relationship between gold pXRF and gold concentration was observed in both experimental and MC simulation data (R2 > 0.99). All Au vials were apparent in the experimental and simulated pXFCT images. Specifically, the 3% Au vial was detectable in the experimental [contrast-to-noise ratio (CNR) = 5.8] and simulated (CNR = 11.5) pXFCT image. Due to fluorescence x-ray attenuation in the higher concentration vials, the 4% and 5% Au contrast were underestimated by 10% and 15%, respectively, in both the experimental and simulated pXFCT images. Conclusions: Proton-induced x-ray fluorescence CT imaging of 3%–5% gold solutions in a small animal sized water phantom has been demonstrated for the first time by means of experiments and MC simulations. PMID:25652502

Bazalova-Carter, Magdalena; Ahmad, Moiz; Matsuura, Taeko; Takao, Seishin; Matsuo, Yuto; Fahrig, Rebecca; Shirato, Hiroki; Umegaki, Kikuo; Xing, Lei

2015-01-01

21

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

NASA Astrophysics Data System (ADS)

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 ?m for x-ray fluorescence and absorption spectroscopies. Quantitative x-ray fluorescence (XRF) analysis gives precise elemental composition and correlations, while x-ray absorption spectroscopy (XAS) gives the chemical state and local atomic coordination for a selected atomic species. These two techniques can be used in conjunction with one another on a wide range of samples, including minerals, glasses, fluid inclusions, soils, sediments, and plant tissue. This x-ray microprobe is part of the GeoSoilEnviroCARS user facility, available for use in all areas geological, soil, and environmental sciences, and selected examples from these fields will be given.

Newville, M.; Sutton, S.; Rivers, M.

2002-12-01

22

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

SciTech Connect

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 and present an outlook.

Frank, M.

1997-08-01

23

X?ray fluorescence spectrometry in art and archaeology  

Microsoft Academic Search

This paper presents examples of analyses by x-ray fluorescence (XRF) spectrometry in art and archaeology, including pigments in paint layers and illuminated manusripts, of iridescent glasses and of medieval coins. Theoretical aspects of information depths and shielding effects in layered materials are discussed. Element maps were experimentally obtained by a specially designed x-ray spectrometer (1 1 mm pixel resolution) and

X-RAY SPECTROMETRY; Michael Mantler

2000-01-01

24

Relation between copper L x-ray fluorescence and 2p x-ray photoelectron spectroscopies  

Microsoft Academic Search

Lalpha1,2,beta1(L3,2-V) x-ray fluorescence spectra (XRF) and 2p1\\/2,3\\/2 x-ray photoelectron spectra (XPS) of various copper compounds are measured. It is found that the intensity of the high-energy hump of the Cu Lalpha XRF has a correlation with that of the high-binding-energy satellite (corresponding to the poorly screened 2p-1 final state) of the Cu 2p3\\/2 XPS. While both the poorly screened peak

Jun Kawai; Kuniko Maeda; Katsumi Nakajima; Yohichi Gohshi

1993-01-01

25

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

26

Three-dimensional X-ray fluorescence imaging with confocal full-field X-ray microscope  

Microsoft Academic Search

A confocal full-field X-ray microscope was performed for three-dimensional X-ray fluorescence imaging with sub-micron spatial resolution. The system consists of an illumination system that produces a sheet-like shaped X-ray beam micrified only in one direction, and an X-ray full-field microscope whose optical axis is normal to the illuminating “sheet-beam”. An arbitrary cross-sectional region of the object is irradiated by the

Akihisa Takeuchi; Yasuko Terada; Kentaro Uesugi; Yoshio Suzuki

2010-01-01

27

Wavelength dispersive analysis with the synchrotron x ray fluorescence microprobe  

NASA Technical Reports Server (NTRS)

A wavelength dispersive spectrometer (WDS) was tested on the synchrotron x ray fluorescence microprobe at Brookhaven National Laboratory. Compared to WDS spectra using an electron microprobe, the synchrotron WDS spectra have much better sensitivity and, due to the absence of bremsstrahlung radiation, lower backgrounds. The WDS spectrometer was successfully used to resolve REE L fluorescence spectra from standard glasses and transition metal K fluorescence spectra from kamacite.

Rivers, M. L.; Thorn, K. S.; Sutton, S. R.; Jones, K. W.; Bajt, S.

1993-01-01

28

X-ray frequency combs from optically controlled resonance fluorescence  

NASA Astrophysics Data System (ADS)

An x-ray pulse-shaping scheme is put forward for imprinting an optical frequency comb onto the radiation emitted on a driven x-ray transition, thus producing an x-ray frequency comb. A four-level system is used to describe the level structure of N ions driven by narrow-bandwidth x rays, an optical auxiliary laser, and an optical frequency comb. By including many-particle enhancement of the emitted resonance fluorescence, a spectrum is predicted consisting of equally spaced narrow lines which are centered on an x-ray transition energy and separated by the same tooth spacing as the driving optical frequency comb. Given an x-ray reference frequency, our comb could be employed to determine an unknown x-ray frequency. While relying on the quality of the light fields used to drive the ensemble of ions, the model has validity at energies from the 100 eV to the keV range.

Cavaletto, Stefano M.; Harman, Zoltán; Buth, Christian; Keitel, Christoph H.

2013-12-01

29

Diffraction and holography of photoelectrons and fluorescent x-rays  

SciTech Connect

Photoelectron diffraction is by now a powerful technique for studying surface structures, with special capabilities for resolving chemical and magnetic states of atoms and deriving direct structural information from both forward scattering and backscattering. Fitting experiment to theory can lead to structural accuracies in the 0.03 {Angstrom} range. Holographic inversions of such diffraction data also show considerable promise for deriving local three-dimensional structures around a given emitter with accuracies of 0.2--0.3 {Angstrom}. Resolving the photoelectron spin in some way and using circularly polarized radiation for excitation provide added dimensions for the study of magnetic systems and chiral experimental geometries. Synchrotron radiation with the highest brightness and energy resolution, as well as variable polarization, is crucial to the full exploitation of these techniques. X-ray fluorescence holography also has promise for structural studies, but will require intense excitation sources and multichannel detection to be feasible.

Fadley, C.S. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Davis, CA (United States). Dept. of Physics

1993-04-01

30

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

NASA Astrophysics Data System (ADS)

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 rays are produced by (1) the elastic scattering of solar X rays by atmospheric neutrals and (2) the absorption of solar X rays in the carbon K-shell followed by fluorescent emission. The carbon atoms are found in methane molecules located below the homopause. In this paper we present the results of calculations of the scattering albedo for soft X rays. We also show the calculated X-ray intensity for a range of atmospheric abundances for Jupiter and Saturn and for a number of solar irradiance spectra. The model calculations are compared with recent X-ray observations of Jupiter and Saturn. We conclude that the emission of soft X rays from the disks of Jupiter and Saturn can be largely explained by the scattering and fluorescence of solar soft X rays. We suggest that measured X-ray intensities from the disk regions of Jupiter and Saturn can be used to constrain both the absolute intensity and the spectrum of solar X rays.

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

2006-07-01

31

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

32

Preparation of tissue samples for X-ray fluorescence microscopy  

Microsoft Academic Search

As is well-known, trace elements, especially metals, play an important role in the pathogenesis of many disorders. The topographic and quantitative elemental analysis of pathologically changed tissues may shed some new light on processes leading to the degeneration of cells in the case of selected diseases. An ideal and powerful tool for such purpose is the Synchrotron Microbeam X-ray Fluorescence

Joanna Chwiej; Magdalena Szczerbowska-Boruchowska; Marek Lankosz; Slawomir Wojcik; Gerald Falkenberg; Zdzislaw Stegowski; Zuzanna Setkowicz

2005-01-01

33

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

34

Demonstration of x-ray fluorescence imaging of a high-energy-density plasma.  

PubMed

Experiments at the Trident Laser Facility have successfully demonstrated the use of x-ray fluorescence imaging (XRFI) to diagnose shocked carbonized resorcinol formaldehyde (CRF) foams doped with Ti. One laser beam created a shock wave in the doped foam. A second laser beam produced a flux of vanadium He-? x-rays, which in turn induced Ti K-shell fluorescence within the foam. Spectrally resolved 1D imaging of the x-ray fluorescence provided shock location and compression measurements. Additionally, experiments using a collimator demonstrated that one can probe specific regions within a target. These results show that XRFI is a capable alternative to path-integrated measurements for diagnosing hydrodynamic experiments at high energy density. PMID:25430348

MacDonald, M J; Keiter, P A; Montgomery, D S; Biener, M M; Fein, J R; Fournier, K B; Gamboa, E J; Klein, S R; Kuranz, C C; LeFevre, H J; Manuel, M J-E; Streit, J; Wan, W C; Drake, R P

2014-11-01

35

HIgh Rate X-ray Fluorescence Detector  

SciTech Connect

The purpose of this project was to develop a compact, modular multi-channel x-ray detector with integrated electronics. This detector, based upon emerging silicon drift detector (SDD) technology, will be capable of high data rate operation superior to the current state of the art offered by high purity germanium (HPGe) detectors, without the need for liquid nitrogen. In addition, by integrating the processing electronics inside the detector housing, the detector performance will be much less affected by the typically noisy electrical environment of a synchrotron hutch, and will also be much more compact than current systems, which can include a detector involving a large LN2 dewar and multiple racks of electronics. The combined detector/processor system is designed to match or exceed the performance and features of currently available detector systems, at a lower cost and with more ease of use due to the small size of the detector. In addition, the detector system is designed to be modular, so a small system might just have one detector module, while a larger system can have many â?? you can start with one detector module, and add more as needs grow and budget allows. The modular nature also serves to simplify repair. In large part, we were successful in achieving our goals. We did develop a very high performance, large area multi-channel SDD detector, packaged with all associated electronics, which is easy to use and requires minimal external support (a simple power supply module and a closed-loop water cooling system). However, we did fall short of some of our stated goals. We had intended to base the detector on modular, large-area detectors from Ketek GmbH in Munich, Germany; however, these were not available in a suitable time frame for this project, so we worked instead with pnDetector GmbH (also located in Munich). They were able to provide a front-end detector module with six 100 m^2 SDD detectors (two monolithic arrays of three elements each) along with associated preamplifiers; these detectors surpassed the performance we expected to get from the Ketek detectors, however they are housed in a sealed module, which does not offer the ease of repair and expandability weâ??d hoped to achieve with the Ketek SDDâ??s. Our packaging efforts were quite successful, as we came up with a very compact way to mount the detector and to house the associated electronics, as well as a very effective way to reliably take out the heat (from the electronics as well as the detectorâ??s Peltier coolers) without risk of condensation and without external airflow or vibration, which could create problems for the target applications. While we were able to design compact processing electronics that fit into the detector assembly, they are still at the prototype stage, and would require a significant redesign to achieve product status. We have not yet tested this detector at a synchrotron facility; we do still plan on working with some close contacts at the nearby Stanford Synchrotron Radiation Laboratory (SSRL) to get some testing with the beam (using existing commercial electronics for readout, as the integrated processor is not ready for use).

Grudberg, Peter Matthew [XIA LLC

2013-04-30

36

SR x-ray fluorescence imaging by image reconstruction technique  

NASA Astrophysics Data System (ADS)

X-ray fluorescence imaging was made by the image reconstruction technique combined with synchrotron radiation. The monochromated synchrotron x-rays of line shape were used for the excitation of elements or the chemical state of an element. The sample was scanned with the rotational and translational motion, then the data was numerically transformed to the two-dimensional distribution of elements by the back-projection technique. In this method, the signal-to-background ratio was improved compared with the point scanning method. The application to the chemical state imaging of the sintered iron ore was demonstrated. The possibility of high resolution imaging was also studied using an asymmetric diffraction. A line-shaped x-ray beam as narrow as 4 ?m was obtained.

Iida, Atsuo; Takahashi, Mamoru; Sakurai, Kenji; Gohshi, Yohichi

1989-07-01

37

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

38

X-ray fluorescence microprobe imaging in biology and medicine.  

PubMed

Characteristic X-ray fluorescence is a technique that can be used to establish elemental concentrations for a large number of different chemical elements simultaneously in different locations in cell and tissue samples. Exposing the samples to an X-ray beam is the basis of X-ray fluorescence microscopy (XFM). This technique provides the excellent trace element sensitivity; and, due to the large penetration depth of hard X-rays, an opportunity to image whole cells and quantify elements on a per cell basis. Moreover, because specimens prepared for XFM do not require sectioning, they can be investigated close to their natural, hydrated state with cryogenic approaches. Until several years ago, XFM was not widely available to bio-medical communities, and rarely offered resolution better then several microns. This has changed drastically with the development of third-generation synchrotrons. Recent examples of elemental imaging of cells and tissues show the maturation of XFM imaging technique into an elegant and informative way to gain insight into cellular processes. Future developments of XFM-building of new XFM facilities with higher resolution, higher sensitivity or higher throughput will further advance studies of native elemental makeup of cells and provide the biological community including the budding area of bionanotechnology with a tool perfectly suited to monitor the distribution of metals including nanovectors and measure the results of interactions between the nanovectors and living cells and tissues. PMID:17006954

Paunesku, Tatjana; Vogt, Stefan; Maser, Jörg; Lai, Barry; Woloschak, Gayle

2006-12-15

39

High spatial resolution in x-ray fluorescence  

SciTech Connect

The design of diffracting crystals for use in x-ray fluorescence spectrometers is discussed. Characteristics of the Johan and Johansson geometries are discussed and intensity profiles are developed. If the diffraction line has a finite width, concentration gradients will not be faithfully reproduced by gradients in the signal as the sample is scanned. Boundary effects for four types of concentration gradient are presented; as step function, linear gradients, exponential gradient, and Gaussian gradient. (DWL) 13 refs., 8 figs.

Zahrt, J.D.

1986-01-01

40

Optimized Detector Angular Configuration Increases the Sensitivity of X-ray Fluorescence Computed Tomography (XFCT).  

PubMed

In this work we demonstrated that an optimized detector angular configuration based on the anisotropic energy distribution of background scattered x-rays improves XFCT detection sensitivity. We built an XFCT imaging system composed of a bench-top fluoroscopy x-ray source, a CdTe x-ray detector, and a phantom motion stage. We imaged a 6.4-cm diameter phantom containing different concentrations of gold solution and investigated the effect of detector angular configuration on XFCT image quality. Based on our previous theoretical study, three detector angles were considered. The xray fluorescence detector was first placed at 145° (approximating back-scatter) to minimize scatter x-rays. XFCT image quality was compared to images acquired with the detector at 60° (forward-scatter) and 90° (side-scatter). The datasets for the three different detector positions were also combined to approximate an isotropically arranged detector. The sensitivity was optimized with detector in the 145° back-scatter configuration counting the 78-keV gold K?1 x-rays. The improvement arose from the reduced energy of scattered x-ray at the 145° position and the large energy separation from gold K?1 x-rays. The lowest detected concentration in this configuration was 2.5 mgAu/mL (or 0.25% Au with SNR = 4.3). This concentration could not be detected with the 60°, 90°, or isotropic configurations (SNRs = 1.3, 0, 2.3, respectively). XFCT imaging dose of 14 mGy was in the range of typical clinical x-ray CT imaging doses. To our knowledge, the sensitivity achieved in this experiment is the highest in any XFCT experiment using an ordinary bench-top x-ray source in a phantom larger than a mouse (> 3 cm). PMID:25474808

Ahmad, Moiz; Bazalova-Carter, Magdalena; Fahrig, Rebecca; Xing, Lei

2014-12-01

41

Multi-angular regolith effects on planetary soft X-ray fluorescence spectroscopy  

NASA Astrophysics Data System (ADS)

Fluorescent X-rays from the surfaces of airless planetary bodies in the inner solar system have been measured by instruments on several spacecraft. MESSENGER carries an X-ray spectrometer (XRS) on-board and has already attempted to obtain fluorescent X-rays from the Hermean surface. BepiColombo will later on carry an X-ray telescope (MIXS-T) along with a more conventional collimating detector (MIXS-C) to the Hermean orbit, supported by a next-generation X-ray solar monitor (SIXS). These instruments will provide unprecedented knowledge about the geochemical properties of the Hermean regolith. X-ray emission from planetary surfaces follows photoionisation by incident solar X-rays and charged particles and reveals information about the elemental composition of the surface. Analyses of X-ray spectra, obtained by orbiting spacecraft, use both the relative intensities of elemental emission lines (e.g., Ca/Si, Fe/Si) and absolute abundancies of the elements to determine the geochemistry of the target body. Historically, the analysis of X-ray spectra has largely assumed that surfaces can be considered as homogeneous plane-parallel media. It has been shown, however, that fluorescent line intensities are affected by the physical properties of the target surface (e.g., surface roughness of the regolith) as a function of the viewing and illumination geometry of observations in a way that cannot be explained by the traditional models. We describe experimental investigations where we simulated the effects of regolith properties on the fluorescent lines measured by an orbiting instrument, with a large variety of illumination and viewing angles. The planetary regolith analogue used in these experiments was a terrestrial, olivine rich basalt, which has been used by previous authors as an analogue to the lunar maria. The basalt samples were ground to powder and sieved to discriminate particles in the ranges, <75 micrometers, 75-250 micrometers, and 250-500 micrometers. These separate powders were then pressed into solid pellets. The separation of particles with different sizes allows some determination of the effects due to changes in, e.g., surface roughness. The pellets were imaged with a CT scanner to obtain the physical parameters of the samples. All measurements were made at near-vacuum pressures to prevent absorption of fluorescent X-rays in air. The relative fluorescent line ratios of several major rock-forming elements (e.g., Si, K, Ca, Ti, Fe) were measured. In addition to experimental studies we have simulated the X-ray emission from a regolith using a numerical Monte-Carlo ray-tracing model. This model simulates a regolith of spherical particles, with defined physical properties (particle size distribution, packing density, etc.) and with a realistic macro-scale surface roughness characteristics generated by constraining the surface with a fractional-Brownian-motion surface model. A comparison is made between the modelling and experimental results to validate the modelling. A good agreement between the results is found. We find that both the measured and the simulated spectra become increasingly hard as the phase angle increases (i.e., X-ray lines at higher energies are enhanced relative to those at lower energies). Some hardening of spectra is predicted by the fundamental parameters equation (FPE) of X-ray fluorescence, which assumes a smooth, flat, and homogeneous surface, but we observe further spectral hardening that is in excess to that predicted by the FPE and that this excess hardening is also a function of the surface roughness. We propose to use modelling similar to ours for the data analysis of soft X-ray fluorescence spectra to take the multi-angular effects related to the physical properties of the regolith into account.

Näränen, J.; Parviainen, H.; Carpenter, J.; Muinonen, K.

2009-04-01

42

Hybrid fluorescence tomography/x-ray tomography improves reconstruction quality  

NASA Astrophysics Data System (ADS)

A novel hybrid imaging system for simultaneous X-ray and Fluorescence Tomography is presented, capitalizing on 360°-projection free-space fluorescence tomography. The system is implemented within a commercial micro-CT scanner allowing reconstructions with a resolution of 95?m. Acquired data sets are intrinsically coregistered in the same coordinate system and can be used to correctly localize reconstructed fluorescence distributions with morphological features. More importantly, the micro-CT data, automatically segmented into different organ and tissue segments can be used to guide the fluorescence reconstruction algorithm and reduce the ill coditioning of the inverse problem. We showcase the use of the system and the improvements in image quality for lesions in brain and lung.

Schulz, R. B.; Ale, A.; Sarantopoulos, A.; Freyer, M.; Söhngen, R.; Zientkowska, M.; Ntziachristos, V.

2009-07-01

43

Three-dimensional x-ray fluorescence mapping of a gold nanoparticle-loaded phantom  

SciTech Connect

Purpose : X-ray fluorescence (XRF) is a promising technique with sufficient specificity and sensitivity for identifying and quantifying features in small samples containing high atomic number (Z) materials such as iodine, gadolinium, and gold. In this study, the feasibility of applying XRF to early breast cancer diagnosis and treatment is studied using a novel approach for three-dimensional (3D) x-ray fluorescence mapping (XFM) of gold nanoparticle (GNP)-loaded objects in a physical phantom at the technical level. Methods : All the theoretical analysis and experiments are conducted under the condition of using x-ray pencil beam and a compactly integrated x-ray spectrometer. The penetrability of the fluorescence x-rays from GNPs is first investigated by adopting a combination of BR12 with 70 mm/50 mm in thickness on the excitation/emission path to mimic the possible position of tumor goldin vivo. Then, a physical phantom made of BR12 is designed to translate in 3D space with three precise linear stages and subsequently the step by step XFM scanning is performed. The experimental technique named as background subtraction is applied to isolate the gold fluorescence from each spectrum obtained by the spectrometer. Afterwards, the attenuations of both the incident primary x-ray beam with energies beyond the gold K-edge energy (80.725 keV) and the isolated gold K{sub ?} fluorescence x-rays (65.99 –69.80 keV) acquired after background subtraction are well calibrated, and finally the unattenuated K{sub ?} fluorescence counts are used to realize mapping reconstruction and to describe the linear relationship between gold fluorescence counts and corresponding concentration of gold solutions. Results : The penetration results show that the goldK{sub ?} fluorescence x-rays have sufficient penetrability for this phantom study, and the reconstructed mapping results indicate that both the spatial distribution and relative concentration of GNPs within the designed BR12 phantom can be well identified and quantified. Conclusions : Although the XFM method in this investigation is still studied at the technical level and is not yet practical for routinein vivo mapping tasks with GNPs, the current penetrability measurements and phantom study strongly suggest the feasibility to establish and develop a 3D XFM system.

Ren, Liqiang; Wu, Di; Li, Yuhua; Liu, Hong, E-mail: liu@ou.edu [Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States)] [Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019 (United States); Wang, Ge [Biomedical Imaging Cluster and Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)] [Biomedical Imaging Cluster and Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Wu, Xizeng [Department of Radiology, University of Alabama, Birmingham, Alabama 35233 (United States)] [Department of Radiology, University of Alabama, Birmingham, Alabama 35233 (United States)

2014-03-15

44

X-ray laser cavity experiments  

Microsoft Academic Search

Progress has been made toward the development of multipass, soft x-ray laser cavities operating in a spectral range around 200 A. Experimental results on the characterization of normal incidence multilayer mirrors, the survival of multilayer mirrors in the hostile x-ray laser environment, and the performance of double pass cavities at 206 A to 209 A are presented.

N. M. Ceglio; D. P. Gaines; J. Trebes; A. M. Hawryluk; D. G. Stearns; G. L. Howe

1987-01-01

45

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

PubMed

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

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

2012-01-01

46

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

PubMed Central

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

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

2012-01-01

47

X-Ray Fluorescence Imaging With the Medipix2 Single-Photon Counting Detector  

Microsoft Academic Search

Material-resolved X-ray imaging or colour X-ray imaging is of a great interest for many applications ranging from physics, industry to medicine and biology. X-ray fluorescence offers a method for producing such images if the energies and positions of origin of the fluorescent photons can be adequately resolved.

J. Uher; G. Harvey; J. Jakubek

2012-01-01

48

Evaluating the variability of ceramics with x-ray fluorescence  

SciTech Connect

Our assessment of prehistoric trade in ceramics depends on our ability to identify and distinguish different sources of manufacture. For the American Southwest, archaeologists have proposed various models of ceramic manufacture and exchange. Until recently, conflicting hypotheses were tested mainly on the basis of petrographic analysis of nonplastic tempering materials. We have extended these analyses to include x-ray fluorescence (XRF). XRF provides a fast and inexpensive means of analyzing large numbers of samples. Since 1982, approximately 500 prehistoric sherds and 40 prepared clay and mineral samples have been examined with XRF. Multivariate statistical techniques have been applied to help identify groupings of samples with possible archaeological significance.

Crown, P.L.; Schwalbe, L.A.; London, J.R.

1984-01-01

49

Portable X-ray Fluorescence Unit for Analyzing Crime Scenes  

NASA Astrophysics Data System (ADS)

Goddard Space Flight Center and the National Institute of Justice have teamed up to apply NASA technology to the field of forensic science. NASA hardware that is under development for future planetary robotic missions, such as Mars exploration, is being engineered into a rugged, portable, non-destructive X-ray fluorescence system for identifying gunshot residue, blood, and semen at crime scenes. This project establishes the shielding requirements that will ensure that the exposure of a user to ionizing radiation is below the U.S. Nuclear Regulatory Commission's allowable limits, and also develops the benchtop model for testing the system in a controlled environment.

Visco, A.

2003-12-01

50

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

51

The Polar Ionospheric X-ray Imaging Experiment (PIXIE)  

Microsoft Academic Search

The Polar Ionospheric X-ray Imaging Experiment (PIXIE) is an X-ray multiple-pinhole camera designed to image simultaneously an entire auroral region from high altitudes. It will be mounted on the despun platform of the POLAR spacecraft and will measure the spatial distribution and temporal variation of auroral X-ray emissions in the 2 to 60 keV energy range on the day side

W. L. Imhof; K. A. Spear; J. W. Hamilton; B. R. Higgins; M. J. Murphy; J. G. Pronko; R. R. Vondrak; D. L. McKenzie; C. J. Rice; D. J. Gorney; D. A. Roux; R. L. Williams; J. A. Stein; J. Bjordal; J. Stadsnes; K. Njoten; T. J. Rosenberg; L. Lutz; D. Detrick

1995-01-01

52

The X-ray Fluorescence Microscopy Beamline at the Australian Synchrotron  

NASA Astrophysics Data System (ADS)

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 ?-XRF and ?-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.; de Jonge, M. D.; Howard, D. L.; Lewis, W.; McKinlay, J.; Starritt, A.; Kusel, M.; Ryan, C. G.; Kirkham, R.; Moorhead, G.; Siddons, D. P.

2011-09-01

53

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

54

Inorganic chemical investigation by X-ray fluorescence analysis - The Viking Mars Lander  

NASA Technical Reports Server (NTRS)

The inorganic chemical investigation experiment added in August 1972 to the Viking Lander scientific package uses an energy-dispersive X-ray fluorescence spectrometer in which four sealed, gas-filled proportional counters detect X-rays emitted from samples of the Martian surface materials irradiated by X-rays from radioisotope sources (Fe-55 and Cd-109). The instrument is inside the Lander body, and samples are to be delivered to it by the Viking Lander Surface Sampler. Instrument design is described along with details of the data processing and analysis procedures. 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 per cent (for major elements) depending on the element in question.

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

1973-01-01

55

Human thyroid specimen imaging by fluorescent x-ray computed tomography with synchrotron radiation  

NASA Astrophysics Data System (ADS)

Fluorescent x-ray computed tomography (FXCT) is being developed to detect non-radioactive contrast materials in living specimens. The FXCT system consists of a silicon (111) channel cut monochromator, an x-ray slit and a collimator for fluorescent x ray detection, a scanning table for the target organ and an x-ray detector for fluorescent x-ray and transmission x-ray. To reduce Compton scattering overlapped on the fluorescent K(alpha) line, incident monochromatic x-ray was set at 37 keV. The FXCT clearly imaged a human thyroid gland and iodine content was estimated quantitatively. In a case of hyperthyroidism, the two-dimensional distribution of iodine content was not uniform, and thyroid cancer had a small amount of iodine. FXCT can be used to detect iodine within thyroid gland quantitatively and to delineate its distribution.

Takeda, Tohoru; Yu, Quanwen; Yashiro, Toru; Yuasa, Tetsuya; Hasegawa, Yasuo; Itai, Yuji; Akatsuka, Takao

1999-09-01

56

Novel sampling strategies for x-ray fluorescence computed tomography  

NASA Astrophysics Data System (ADS)

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. While this line-by-line acquisition is slow, it does provide remarkable flexibility in sampling, since the sampling intervals and patterns are not limited by detector hardware as they are in many imaging modalities. In this work we discuss several ways of exploiting this flexibility to increase imaging speed without sacrificing image quality. This includes: (1) scanning only the half of the object nearest the detector while rotating through 360 degrees, (2) performing so-called interlaced sampling in which the sampling patterns at even and odd projection views are offset relative to one another, and (3) performing 3D helical scanning in which only the half of the object nearest the detector is scanned. The helical sampling is coupled with a novel Fourier-based interpolation scheme we have previously introduced for helical CT.

La Rivière, Patrick J.; Vargas, Phillip

2008-08-01

57

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

58

X-ray fluorescence and the study of microcirculation  

NASA Astrophysics Data System (ADS)

The feasibility of using K-shell X-ray fluorescence (XRF) technique for study of subchondral bone microcirculation in ex vivo samples is examined. Studies have been carried out at the Daresbury Laboratory Synchrotron Radiation Source (SRS) ultra-dilute extended X-ray absorption fine structure beamline. Initial investigations were made on fine-bore capillaries with diameters of either 500 or 200 ?m, attenuated by up to 2 mm of Perspex and containing dilute iodine-based contrast media. This allowed comparison to be made with the capabilities of angiographic imaging systems, also allowing definition of suitable XRF set-up parameters for subsequent microcirculation studies. Measurements were obtained in 30 s run times, for concentrations of iodine ( Kab 33.164 keV) down to <0.4 mg I 2/(ml saline). Intensities were linear up to 3.7 mg/ml, self-absorption becoming significant for concentrations beyond this. To determine detection limits, preliminary studies of subchondral bone microcirculation were made on bone sections which were known to be poorly infused with silver-coated ( Kab 25.517 keV) 30 ?m diameter microspheres. For a 2 mm slice of bone, the presence of small numbers of silver-coated microspheres were detected in the first 2 mm layer from the surface, at a level equivalent to ˜1 ppm of silver solution.

Muthuvelu, P.; Hugtenburg, R. P.; Bradley, D. A.; Winlove, C. P.

2004-01-01

59

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. PMID:22444530

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

2013-01-01

60

Evaluation of Portable X-Ray Fluorescence (XRF) Analyzer for Zirconium-Thickness Measurements  

SciTech Connect

This Technical Evaluation Report provides details of preliminary testing/experiments performed using a handheld X-ray fluorescence analyzer. The analyzer will be utilized in upcoming fuel-foil-rolling optimization studies at the INL. The studies are being performed in support of DOE’s Office of Global Threat Reduction -- Reactor Conversion Subprogram. Details of the equipment used, operating parameters, and measurement results are provided in this report.

Glenn Moore

2013-09-01

61

Determination of thorium by fluorescent x-ray spectrometry  

USGS Publications Warehouse

A fluorescent x-ray spectrographic method for the determination of thoria in rock samples uses thallium as an internal standard. Measurements are made with a two-channel spectrometer equipped with quartz (d = 1.817 A.) analyzing crystals. Particle-size effects are minimized by grinding the sample components with a mixture of silicon carbide and aluminum and then briquetting. Analyses of 17 samples showed that for the 16 samples containing over 0.7% thoria the average error, based on chemical results, is 4.7% and the maximum error, 9.5%. Because of limitations of instrumentation, 0.2% thoria is considered the lower limit of detection. An analysis can be made in about an hour.

Adler, I.; Axelrod, J.M.

1955-01-01

62

Counter tube window and X-ray fluorescence analyzer study  

NASA Technical Reports Server (NTRS)

A study was performed to determine the best design tube window and X-ray fluorescence analyzer for quantitative analysis of Venusian dust and condensates. The principal objective of the project was to develop the best counter tube window geometry for the sensing element of the instrument. This included formulation of a mathematical model of the window and optimization of its parameters. The proposed detector and instrument has several important features. The instrument will perform a near real-time analysis of dust in the Venusian atmosphere, and is capable of measuring dust layers less than 1 micron thick. In addition, wide dynamic measurement range will be provided to compensate for extreme variations in count rates. An integral pulse-height analyzer and memory accumulate data and read out spectra for detail computer analysis on the ground.

Hertel, R.; Holm, M.

1973-01-01

63

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

64

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

65

Comparison of total-reflection X-ray fluorescence, static and portable energy dispersive X-ray fluorescence spectrometers for art and archeometry studies  

Microsoft Academic Search

In this paper, a Total-reflection X-ray Fluorescence (TXRF), a static and a portable Energy Dispersive X-ray Fluorescence (EDXRF) spectrometers are described. Both the equipments and the techniques employed in the field of the art and archeometry are compared. Some applications in this area are presented as well. The aim of the work is to know which spectrometer is the best

M. Ardid; J. L. Ferrero; D. Juanes; J. L. Lluch; C. Roldán

2004-01-01

66

Recent X-Ray Laser Characterization Experiments at LLNL  

SciTech Connect

We report on a series of experiments, using the COMET picosecond facility, designed to characterize and develop different x-ray laser sources. This work encompasses collisional pumping of slab and gas puff targets.

Smith, R F; Dunn, J; Nilsen, J; Fiedorowicz, H; Bartnik, A; Shlyaptsev, V N

2002-02-26

67

X-ray fluorescence imaging with the Medipix2 single-photon counting detector  

Microsoft Academic Search

Material-resolved X-ray imaging or colour X-ray imaging is of a great interest for many applications ranging from physics, industry to medicine and biology. X-ray fluorescence offers a method for producing such images if the energies and positions of origin of the fluorescent photons can be adequately resolved. This paper describes application of the Medipix2 single photon counting imaging detector (256×256

J. Uher; G. Harvey; J. Jakubek

2010-01-01

68

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)

2011-04-26

69

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

70

Preliminary Results from the ALEXIS Ultrasoft X-ray Experiment  

Microsoft Academic Search

We report preliminary results from the ALEXIS (Array of Low-Energy X-ray Imaging Sensors) ultrasoft X-ray experiment, which is scheduled to launch in spring 1993. ALEXIS is a monitor experiment that consists of 6 compact normal-incidence telescopes tuned to narrow bands centered on 66, 71, and 93 eV (186, 172, and 130 Angstroms). The 66 and 71 eV bandpasses are centered

W. Priedhorsky; J. J. Bloch; B. Edwards; D. Roussel-Dupre; B. W. Smith; O. H. W. Siegmund; T. Carone; S. Cully; J. Warren; J. Vallerga

1993-01-01

71

X-ray fluorescence analysis with synchrotron radiation  

NASA Astrophysics Data System (ADS)

The method of trace element analysis by X-ray fluorescence detection has been improved to an especially efficient multielement method for the ng to pg range in matrices containing light elements by the use of synchrotron radiation for excitation. It was necessary to determine the intensity and polarisation of the synchrotron radiation quantitatively. Inclusion of the vertical electron beam diameter and the divergence into the calculation, and definition of an effective vertical beam diameter by fitting the calculated polarisation spectrum leads to quantitative agreement between experimental and calculated absolute intensity spectra of scattered and fluorescent radiation of well-defined samples. This means that absolute mass determinations are in principle possible. The physical limits of detection calculated with these data agree very well with the experimental results. The limits of detection for special elements can be optimised by using different absorbers in the primary beam. They range from 0.05 to 0.2 ?g for organic matrix. This implies an absolute physical detection limit of 0.1 to 0.4 pg for a diameter of the primary beam of 0.5 mm and a sample of 1 mg/cm 2.

Knöchel, A.; Petersen, W.; Tolkiehn, G.

1983-04-01

72

Oscillating dipole model for the X-ray standing wave enhanced fluorescence in periodic multilayers  

E-print Network

Oscillating dipole model for the X-ray standing wave enhanced fluorescence in periodic multilayers Abstract Periodic multilayers give rise to enhanced X-ray fluorescence when a regime of standing waves with standing wave regime of primary radiation. We present a theoretical approach based on the oscillating

Paris-Sud XI, Université de

73

The BioCAT Microprobe for X-Ray Fluorescence Imaging, MicroXAFS and Microdiffraction Studies on Biological Samples  

SciTech Connect

Microbeam capabilities have been recently added to the Biophysics Collaborative Access Team (BioCAT) beamline 18-ID at the Advanced Photon Source to allow x-ray elemental mapping, micro x-ray absorption fine structure and microdiffraction studies on biological samples. The microprobe setup comprises a pair of platinum coated silicon KB mirrors; a sample holder mounted in a high precision positioner (100 nm accuracy); fluorescence detectors including a Si drift detector, Fe and Zn Bent Laue analyzers and a Ge detector; and a CCD detector for micro-diffraction experiments. The energy range of the microprobe is from 3.5 keV up to 17 keV. The fast scanning capabilities of the Bio-CAT beamline facilitate rapid acquisition of x-ray elemental images and micro-XAFS spectra. This paper reports the results of commissioning the KB mirror system and its performance in initial x-ray fluorescence mapping and micro-diffraction studies.

Barrea, R.A.; Gore, D.; Kondrashkina, E.; Weng, T.; Heurich, R.; Vukonich, M.; Orgel, J.; Davidson, M.; Collingwood, J.F.; Mikhaylova, A.; Irving, T.C. (IIT); (Keele); (Florida)

2007-07-31

74

High-throughput screening with micro-x-ray fluorescence  

SciTech Connect

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. [Chemistry Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); X-ray Optical Systems, Inc., East Greenbush, New York 12061 (United States)

2005-06-15

75

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

76

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

PubMed

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

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

2013-06-01

77

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

78

Energy response calibration of photon-counting detectors using x-ray fluorescence: a feasibility study  

NASA Astrophysics Data System (ADS)

Accurate energy calibration is critical for the application of energy-resolved photon-counting detectors in spectral imaging. The aim of this study is to investigate the feasibility of energy response calibration and characterization of a photon-counting detector using x-ray fluorescence. A comprehensive Monte Carlo simulation study was performed using Geant4 Application for Tomographic Emission (GATE) to investigate the optimal technique for x-ray fluorescence calibration. Simulations were conducted using a 100?kVp tungsten-anode spectra with 2.7?mm Al filter for a single pixel cadmium telluride (CdTe) detector with 3? × ?3?mm2 in detection area. The angular dependence of x-ray fluorescence and scatter background was investigated by varying the detection angle from 20° to 170° with respect to the beam direction. The effects of the detector material, shape, and size on the recorded x-ray fluorescence were investigated. The fluorescent material size effect was considered with and without the container for the fluorescent material. In order to provide validation for the simulation result, the angular dependence of x-ray fluorescence from five fluorescent materials was experimentally measured using a spectrometer. Finally, eleven of the fluorescent materials were used for energy calibration of a CZT-based photon-counting detector. The optimal detection angle was determined to be approximately at 120° with respect to the beam direction, which showed the highest fluorescence to scatter ratio (FSR) with a weak dependence on the fluorescent material size. The feasibility of x-ray fluorescence for energy calibration of photon-counting detectors in the diagnostic x-ray energy range was verified by successfully calibrating the energy response of a CZT-based photon-counting detector. The results of this study can be used as a guideline to implement the x-ray fluorescence calibration method for photon-counting detectors in a typical imaging laboratory.

Cho, H.-M.; Ding, H.; Ziemer, BP; Molloi, S.

2014-12-01

79

Molecular imaging based on x-ray fluorescent high-Z tracers  

NASA Astrophysics Data System (ADS)

We propose a novel x-ray fluorescence imaging setup for the in vivo detection of high-Z tracer distributions. The main novel aspect is the use of an analyzer-based, energy-resolved detection method together with a radial, scatter reducing collimator. The aim of this work is to show the feasibility of this method by measuring the Bragg reflected K-fluorescence signal of an iodine solution sample in a proof of principle experiment and to estimate the potential of the complete imaging setup using a Monte Carlo simulation, including a quantification of the minimal detectable tracer concentration for in vivo imaging. The proof of principle experiment shows that even for a small detector area of approximately 7 mm2, the collimated and Bragg reflected K-fluorescence signal of a sample containing an iodine solution with a concentration of 50 µg?ml-1 can be detected. The Monte Carlo simulation also shows that the proposed x-ray fluorescence imaging setup has the potential to image distributions of high-Z tracers in vivo at a radiation dose of a few mGy and at tracer concentrations down to 1 µg?ml-1 for iodine in small animals.

Müller, Bernhard H.; Hoeschen, Christoph; Grüner, Florian; Arkadiev, Vladimir A.; Johnson, Thorsten R. C.

2013-11-01

80

RADIOCHEMICAL ANALYSIS BY HIGH SENSITIVITY DUAL-OPTIC MICRO X-RAY FLUORESCENCE  

EPA Science Inventory

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...

81

X-ray laser experiments using double foil nickel targets  

Microsoft Academic Search

New target geometries for collisional excitation X-ray laser experiments (in nickel) were proposed, analyzed, and experimentally studied on the Glass Development Laser (GDL). Experiments using a short line focus lens with new target geometries showed general agreement with predictions. The new geometries are designed to yield a higher gain and reduced refraction due to: (1) a higher plasma density, (2)

T. Boehly; B. Yaakobi; D. Shvarts; D. Meyerhofer; P. Audebert; J. Wang; M. Russotto; B. Boswell; R. Epstein; R. S. Craxton; J. M. Soures

1990-01-01

82

In-Situ Silver Acetylide Silver Nitrate Explosive Deposition Measurements Using X-Ray Fluorescence.  

SciTech Connect

The Light Initiated High Explosive facility utilized a spray deposited coating of silver acetylide - silver nitrate explosive to impart a mechanical shock into targets of interest. A diagnostic was required to measure the explosive deposition in - situ. An X - ray fluorescence spectrometer was deployed at the facility. A measurement methodology was developed to measure the explosive quantity with sufficient accuracy. Through the use of a tin reference material under the silver based explosive, a field calibration relationship has been developed with a standard deviation of 3.2 % . The effect of the inserted tin material into the experiment configuration has been explored.

Covert, Timothy T.

2014-09-01

83

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

84

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

85

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

SciTech Connect

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 SiO{sub 2} optical fibers.

Kayser, Y., E-mail: yves.kayser@psi.ch [Department of Physics, University of Fribourg, 1700 Fribourg (Switzerland); Paul Scherrer Institut, 5232 Villigen-PSI (Switzerland); B?achucki, W.; Dousse, J.-Cl.; Hoszowska, J. [Department of Physics, University of Fribourg, 1700 Fribourg (Switzerland)] [Department of Physics, University of Fribourg, 1700 Fribourg (Switzerland); Neff, M.; Romano, V. [Institute of Applied Physics, University of Bern, 3012 Bern (Switzerland)] [Institute of Applied Physics, University of Bern, 3012 Bern (Switzerland)

2014-04-15

86

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

NASA Astrophysics Data System (ADS)

The ESA/NASA ExoMars mission, due for launch in 2018, has a combined X-ray fluorescence/diffraction instrument, Mars-XRD, as part of the onboard analytical laboratory. The results of some XRF (Xray fluorescence) and XRD (X-ray diffraction) tests using a laboratory chamber with representative performance are reported. A range of standard geological reference materials and analogues were used in these tests.

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

2011-10-01

87

The radiation monitor cosmic X-ray experiment OSO-1  

NASA Technical Reports Server (NTRS)

A comprehensive technical description is presented of the Radiation Monitor which is part of the GSFC cosmic X-ray experiment to be flown on the OSO-1 satellite. The theory of operation, fabrication and assembly, and cone angle determination are reported.

Randall, R. F.

1973-01-01

88

(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

89

X-ray nanoprobes and diffraction-limited storage rings: opportunities and challenges of fluorescence tomography of biological specimens  

PubMed Central

X-ray nanoprobes require coherent illumination to achieve optic-limited resolution, and so will benefit directly from diffraction-limited storage rings. Here, the example of high-resolution X-ray fluorescence tomography is focused on as one of the most voracious demanders of coherent photons, since the detected signal is only a small fraction of the incident flux. Alternative schemes are considered for beam delivery, sample scanning and detectors. One must consider as well the steps before and after the X-ray experiment: sample preparation and examination conditions, and analysis complexity due to minimum dose requirements and self-absorption. By understanding the requirements and opportunities for nanoscale fluorescence tomography, one gains insight into the R&D challenges in optics and instrumentation needed to fully exploit the source advances that diffraction-limited storage rings offer. PMID:25177992

de Jonge, Martin D.; Ryan, Christopher G.; Jacobsen, Chris J.

2014-01-01

90

X-ray fluorescence spectrometry for analysis of fly ash column leachates  

Microsoft Academic Search

An investigation was conducted to determine the suitability of X-ray fluorescence (XRF) for analyzing the complex mixture of elements in fly ash leachates. XRF analysis was found to provide reasonably accurate measurement with coefficients of variation ranging from 2 to 8% for most elements. Sources of error included interferences by stimulation of fluorescent emissions by strong secondary fluorescent radiation, overlap

H. W. Young; M. Boybay; T. Demirel; J. C. Young

1981-01-01

91

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. PMID:20930932

Hayashi, Yasuhiko; Okuyama, Fumio

2010-01-01

92

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

2010-12-28

93

Selenium speciation in whole sediment using X-ray absorption spectroscopy and micro X-ray fluorescence imaging.  

PubMed

A field survey was conducted in a freshwater lake system in the Athabasca Basin, northern Saskatchewan, Canada that receives treated metal mining and milling process effluent containing elevated levels of selenium. Whole sediment, pore water, surface water, and chironomid larvae were analyzed in an attempt to link whole sediment selenium speciation to various environmental factors, including selenium availability to benthic macro-invertebrates, a trophic level through which selenium can enter the diet of higher trophic level organisms. Speciation was measured using synchrotron-based selenium K-edge X-ray absorption spectroscopy (XAS). All lake averages of sediment samples (reference or exposure sites) contained a significant proportion (approximately 50%) of elemental selenium which is relatively insoluble in water, immobile, and not considered to be bioavailable. The presence of elemental selenium was confirmed by extended X-ray absorption fine structure (EXAFS) analysis of select samples. Inorganic metal selenides were also found in whole sediment samples and confirmed using micro X-ray fluorescence imaging. Dissolved selenium concentrations in pore water were correlated to the amount of selenite in whole sediments provided that the sites were classified according to whole sediment sand content. Sand content itself is likely inversely correlated to sediment organic matter content, adsorption sites, and redox potential. PMID:20575568

Wiramanaden, Cheryl I E; Liber, Karsten; Pickering, Ingrid J

2010-07-15

94

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

95

Synchrotron Radiation X-Ray Spectroscopy for Investigations of Intracellular Metallointercalators: X-Ray Fluorescence Imaging and X-Ray Absorption Spectroscopy  

NASA Astrophysics Data System (ADS)

In an effort to determine the therapeutic feasibility of DNA metallointercalators as potential anticancer drugs it is important to confirm that they are capable of targeting DNA in cancer cells or tumours - as is the intended purpose of their design. Microprobe synchrotron radiation X-ray fluorescence (micro-SRXRF) spectroscopy is an ideal technique for investigating the cellular uptake and distribution of metallointercalators. The technique is capable of submicron elemental imaging so that samples as small as individual cells (~10 ?m diameter), and the features within them, can be resolved. Consequently, the technique can ascertain whether intracellular metallointercalators colocalise with DNA; namely, in the nucleus during interphase or at the chromosomes during middle prophase to late anaphase. Metals, such as those commonly incorporated into metallointercalators (e.g., Cr, Ni, Co, Pd, Pt, Ru, Rh), are often naturally present in negligible quantities in cancer cells. This fact, together with their higher atomic number, Z, makes them ideal for direct probing using hard X-ray microprobes (as discussed in Sect. 11.2). There is no need for the incorporation of fluorescent tracker dyes or radioactive labels into their chemical structure. This is advantageous since it is unknown whether such chemical modifications alter the uptake kinetics of the metallointercalator [1, 2].

Dillon, Carolyn T.

96

MESSENGER X-RAY SPECTROMETER DETECTION OF ELECTRON-INDUCED X-RAY FLUORESCENCE FROM MERCURY'S SURFACE. Richard D. Starr (richard.d.starr@nasa.gov)1,2  

E-print Network

spacecraft measures ele- mental abundances on the surface of Mercury by de- tecting fluorescent X-rayMESSENGER X-RAY SPECTROMETER DETECTION OF ELECTRON-INDUCED X-RAY FLUORESCENCE FROM MERCURY, University of California, Los Angeles, CA 90095, USA. Introduction: X-ray emission from solar system bodies

Nittler, Larry R.

97

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

98

Application of X-ray fluorescence to the study of iodine distribution and content in the thyroid  

Microsoft Academic Search

We have been developing an X-ray fluorescence system designed to determine iodine distribution and content in the thyroid. The X-ray fluorescence unit is composed of a 80 kV X-ray excitation beam and a Si(Li) semi-conductor detector. The angle between the X-ray beam and the axis of the detector is 24°. Two single channel analyzers (SCA) are used, the first one

B. Aubert; P. Fragu; M. Di Paola; P. Rougier; M. Tubiana

1981-01-01

99

Monte Carlo simulation applied in total reflection x-ray fluorescence: Preliminary results  

SciTech Connect

The X-ray Fluorescence (XRF) analysis is a technique for the qualitative and quantitative determination of chemical constituents in a sample. This method is based on detection of the characteristic radiation intensities emitted by the elements of the sample, when properly excited. A variant of this technique is the Total Reflection X-ray Fluorescence (TXRF) that utilizes electromagnetic radiation as excitation source. In total reflection of X-ray, the angle of refraction of the incident beam tends to zero and the refracted beam is tangent to the sample support interface. Thus, there is a minimum angle of incidence at which no refracted beam exists and all incident radiation undergoes total reflection. In this study, we evaluated the influence of the energy variation of the beam of incident x-rays, using the MCNPX code (Monte Carlo NParticle) based on Monte Carlo method.

Meira, Luiza L. C.; Inocente, Guilherme F.; Vieira, Leticia D.; Mesa, Joel [Departamento de Fisica e Biofisica - Instituto de Biociencias de Botucatu, Universidade Estadual Paulista Julio de Mesquita Filho (Brazil)

2013-05-06

100

OSO-8 soft X-ray experiment (Wisconsin)  

NASA Technical Reports Server (NTRS)

Information for operating and reducing data from the experiment which was designed to map low energy X-ray background emissions from 130 eV to 35 keV is presented. The detectors, counters, data system, and the gas system are discussed along with the functional operation of the subsystems. A command list indicating preconditions and resulting telemetry response for each command is included.

1975-01-01

101

Portable total reflection x-ray fluorescence analysis in the identification of unknown laboratory hazards  

SciTech Connect

In this study, a portable total reflection x-ray fluorescence (TXRF) spectrometer was used to analyze unknown laboratory hazards that precipitated on exterior surfaces of cooling pipes and fume hood pipes in chemical laboratories. With the aim to examine the accuracy of TXRF analysis for the determination of elemental composition, analytical results were compared with those of wavelength-dispersive x-ray fluorescence spectrometry, scanning electron microscope and energy-dispersive x-ray spectrometry, energy-dispersive x-ray fluorescence spectrometry, inductively coupled plasma atomic emission spectrometry, x-ray diffraction spectrometry (XRD), and x-ray photoelectron spectroscopy (XPS). Detailed comparison of data confirmed that the TXRF method itself was not sufficient to determine all the elements (Z?>?11) contained in the samples. In addition, results suggest that XRD should be combined with XPS in order to accurately determine compound composition. This study demonstrates that at least two analytical methods should be used in order to analyze the composition of unknown real samples.

Liu, Ying, E-mail: liu.ying.48r@st.kyoto-u.ac.jp; Imashuku, Susumu; Sasaki, Nobuharu; Ze, Long; Kawai, Jun [Department of Materials Science and Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Takano, Shotaro; Sohrin, Yoshiki [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Seki, Hiroko; Miyauchi, Hiroya [Kyoto Prefectural Technology Center for Small and Medium Enterprises, Chudojiminami machi, Shimogyo-ku, Kyoto 600-8813 (Japan)

2014-05-15

102

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

103

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

104

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

USGS Publications Warehouse

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

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

1990-01-01

105

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

106

A high-resolution large-acceptance analyzer for X-ray fluorescence and Raman spectroscopy  

SciTech Connect

A newly designed multi-crystal X-ray spectrometer and its applications in the fields of X-ray fluorescence and X-ray Raman spectroscopy are described. The instrument is based on 8 spherically curved Si crystals, each with a 3.5 inch diameter form bent to a radius of 86 cm. The crystals are individually aligned in the Rowland geometry capturing a total solid angle of 0.07 sr. The array is arranged in a way that energy scans can be performed by moving the whole instrument, rather than scanning each crystal by itself. At angles close to back scattering the energy resolution is between 0.3 and 1 eV depending on the beam dimensions at the sample. The instrument is mainly designed for X-ray absorption and fluorescence spectroscopy of transition metals in dilute systems such as metalloproteins. First results of the Mn K{beta} (3p -> 1s) emission in photosystem II are shown. An independent application of the instrument is the technique of X-ray Raman spectroscopy which can address problems similar to those in traditional soft X-ray absorption spectroscopies, and initial results are presented.

Bergmann, Uwe; Cramer, Stephen P.

2001-08-02

107

Spectrally resolving and scattering-compensated x-ray luminescence/fluorescence computed tomography  

NASA Astrophysics Data System (ADS)

The nanophosphors, or other similar materials, emit near-infrared (NIR) light upon x-ray excitation. They were designed as optical probes for in vivo visualization and analysis of molecular and cellular targets, pathways, and responses. Based on the previous work on x-ray fluorescence computed tomography (XFCT) and x-ray luminescence computed tomography (XLCT), here we propose a spectrally-resolving and scattering-compensated x-ray luminescence/fluorescence computed tomography (SXLCT or SXFCT) approach to quantify a spatial distribution of nanophosphors (other similar materials or chemical elements) within a biological object. In this paper, the x-ray scattering is taken into account in the reconstruction algorithm. The NIR scattering is described in the diffusion approximation model. Then, x-ray excitations are applied with different spectra, and NIR signals are measured in a spectrally resolving fashion. Finally, a linear relationship is established between the nanophosphor distribution and measured NIR data using the finite element method and inverted using the compressive sensing technique. The numerical simulation results demonstrate the feasibility and merits of the proposed approach.

Cong, Wenxiang; Shen, Haiou; Wang, Ge

2011-06-01

108

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

109

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

110

Resonance fluorescence in ultrafast and intense x-ray free-electron-laser pulses  

NASA Astrophysics Data System (ADS)

The spectrum of resonance fluorescence is calculated for a two-level system excited by an intense, ultrashort x-ray pulse made available, for instance, by free-electron lasers such as the Linac Coherent Light Source. We allow for inner-shell hole decay widths and destruction of the system by further photoionization. This two-level description is employed to model neon cations strongly driven by x rays tuned to the 1s2p-1?1s-12p transition at 848eV; the x rays induce Rabi oscillations which are so fast that they compete with Ne 1s-hole decay. We predict resonance fluorescence spectra for two different scenarios: first, chaotic pulses based on the self-amplified spontaneous emission principle, like those presently generated at x-ray free-electron-laser facilities and, second, Gaussian pulses which will become available in the foreseeable future with self-seeding techniques. As an example of the exciting opportunities derived from the use of seeding methods, we predict, in spite of the above obstacles, the possibility to distinguish at x-ray frequencies a clear signature of Rabi flopping in the spectrum of resonance fluorescence.

Cavaletto, Stefano M.; Buth, Christian; Harman, Zoltán; Kanter, Elliot P.; Southworth, Stephen H.; Young, Linda; Keitel, Christoph H.

2012-09-01

111

X-ray resonance fluorescence and Rabi flopping for ultrafast and ultraintense pulses  

NASA Astrophysics Data System (ADS)

Resonance fluorescence is scattering of photons off atoms and molecules driven by a near-resonant external electric field; it is a cornerstone of spectroscopy and quantum optics. For intense x rays from existing and upcoming x-ray free electron lasers (FELs) such as the Linac Coherent Light Source (LCLS) in Menlo Park, California, USA, the cyclic excitation and decay of a core electron (Rabi flopping) can compete with spontaneous core-hole decay. We develop a two-level description of x-ray resonance fluorescence and exemplify it for neon cations strongly driven by LCLS light tuned to the 1s,p-1->1s-1,p transition at 848 eV. We compute the time-dependent spectrum of resonance fluorescence in order to study the coherent and fundamentally nonlinear process of Rabi flopping at x-ray frequencies. We predict resonance fluorescence spectra for two different scenarios: first, chaotic pulses generated at present-day LCLS and, second, Gaussian pulses which will become available soon with self-seeding techniques. In the latter case, as an example of the exciting opportunities deriving from the use of seeding methods, we predict a clear signature of Rabi flopping in the spectrum of resonance fluorescence.

Cavaletto, Stefano M.; Harman, Zoltán; Keitel, Christoph H.; Buth, Christian; Kanter, Elliot P.; Young, Linda; Southworth, Stephen H.

2012-06-01

112

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

113

Preliminary Results from the ALEXIS Ultrasoft X-ray Experiment  

NASA Astrophysics Data System (ADS)

We report preliminary results from the ALEXIS (Array of Low-Energy X-ray Imaging Sensors) ultrasoft X-ray experiment, which is scheduled to launch in spring 1993. ALEXIS is a monitor experiment that consists of 6 compact normal-incidence telescopes tuned to narrow bands centered on 66, 71, and 93 eV (186, 172, and 130 Angstroms). The 66 and 71 eV bandpasses are centered on a cluster of emission lines from Fe IX-XII. The 6 telescopes are arranged in pairs and cover three overlapping 33° fields-of-view. During each 30-second spin of the satellite, ALEXIS will monitor the entire anti-solar hemisphere. Each telescope consists of a molybdenum/silicon layered synthetic microstructure (LSM) mirror, a curved-profile microchannel plate detector situated at the prime focus, with wedge-and-strip readout, a thin lexan/titanium/boron or aluminum/carbon filter, electron- rejecting magnets, and readout electronics. The resolution of each telescope is limited by spherical aberration to about 1/2° diameter. ALEXIS, with its wide fields-of-view and well-defined wavelength bands, will complement NASA's Extreme Ultraviolet Explorer and the German/UK Wide Field Camera on ROSAT. It will pursue a number of scientific objectives, including mapping the diffuse background in three bands, performing a narrow-band survey of point sources, searching for transient phenomena, and monitoring variable ultrasoft X-ray sources, such as cataclysmic variables and flare stars, for weeks and months at a time. ALEXIS is serviced by a small satellite bus, launched by a Pegasus air-launched booster, and tracked by a ground station at Los Alamos. ALEXIS thereby exploits modern technology to field a space experiment better, faster, and cheaper. The ALEXIS project was developed under the auspices of the US Department of Energy.

Priedhorsky, W.; Bloch, J. J.; Edwards, B.; Roussel-Dupre, D.; Smith, B. W.; Siegmund, O. H. W.; Carone, T.; Cully, S.; Warren, J.; Vallerga, J.

1993-05-01

114

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

SciTech Connect

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

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

1996-07-01

115

Development of a compact grazing exit X-ray fluorescence spectrometer for fast trace elemental analysis  

NASA Astrophysics Data System (ADS)

A compact grazing exit X-ray fluorescence (GE-XRF) spectrometer was developed in the laboratory. An Al cylindrical collimator for the primary X-rays was placed just above the sample stage. This collimator also played the role of an exit slit to detect fluorescent X-rays at small grazing exit angles. Therefore, no additional exit slit was used in this setup, leading to a compact design. The entire size of the analysis equipment was 80 mm × 200 mm × 170 mm (horizontal × vertical × height). The maximum exit angle was adjusted to the height of the sample stage. The background was drastically reduced at grazing exit angles, enabling trace elemental analysis. A calibration curve was obtained using 10 ?L Ga solutions. Accordingly, the detection limit for Ga was evaluated to be 20 ppb.

Ashida, Takafumi; Tsuji, Kouichi

2014-11-01

116

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

117

Identification of elements in plant drugs and their water infusion using X-ray fluorescence analysis  

Microsoft Academic Search

The present work gives preliminary results of analysis of drug mixtures (NEPHROSAL tea bag) and its water infusion. In a sample of dried drugs the elements K, Ca, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Pb were identified, whereas in their water infusion only Ca, Mn, Zn and Sr were found. The method applied was radionuclide X-ray fluorescence analysis

A. Bumbálová; M. Komová; E. Dejmková

1992-01-01

118

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...

119

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

120

THE DEVELOPMENT OF POTENTIAL THIN STANDARDS FOR CALIBRATION OF X-RAY FLUORESCENCE SPECTROMETRY  

EPA Science Inventory

Thin films containing known concentrations of metals are important for the calibration of X-ray Fluorescence Spectrometry (XRF), especially for the analysis of collected airborne particulate matter. A focused ion-beam sputtering technique has been investigated as a candidate meth...

121

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 ...

122

An Extractive X-Ray Fluorescence Method for Field Screening Lead Paint Sites  

Microsoft Academic Search

A new field method employing a portable x-ray fluorescence (XRF) instrument with a high resolution (cooled) semiconductor detector for the analysis of lead in paint and soil has been developed. This method has many of the advantages of the laboratory methods in terms of excellent precision, accuracy, and stability, yet at the same time the instrument is portable and battery

J. N. Driscoll; C. Wood; T. Powell; J. Scott Askew

1994-01-01

123

Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae.  

PubMed

Trace metals play important roles in normal and in disease-causing biological functions. X-ray fluorescence microscopy reveals trace elements with no dependence on binding affinities (unlike with visible light fluorophores) and with improved sensitivity relative to electron probes. However, X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular material. Here we show that X-ray ptychography can be combined with fluorescence to image both cellular structure and trace element distribution in frozen-hydrated cells at cryogenic temperatures, with high structural and chemical fidelity. Ptychographic reconstruction algorithms deliver phase and absorption contrast images at a resolution beyond that of the illuminating lens or beam size. Using 5.2-keV X-rays, we have obtained sub-30-nm resolution structural images and ?90-nm-resolution fluorescence images of several elements in frozen-hydrated green algae. This combined approach offers a way to study the role of trace elements in their structural context. PMID:25675478

Deng, Junjing; Vine, David J; Chen, Si; Nashed, Youssef S G; Jin, Qiaoling; Phillips, Nicholas W; Peterka, Tom; Ross, Rob; Vogt, Stefan; Jacobsen, Chris J

2015-02-24

124

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

Microsoft Academic Search

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

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

2003-01-01

125

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...

126

Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae  

PubMed Central

Trace metals play important roles in normal and in disease-causing biological functions. X-ray fluorescence microscopy reveals trace elements with no dependence on binding affinities (unlike with visible light fluorophores) and with improved sensitivity relative to electron probes. However, X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular material. Here we show that X-ray ptychography can be combined with fluorescence to image both cellular structure and trace element distribution in frozen-hydrated cells at cryogenic temperatures, with high structural and chemical fidelity. Ptychographic reconstruction algorithms deliver phase and absorption contrast images at a resolution beyond that of the illuminating lens or beam size. Using 5.2-keV X-rays, we have obtained sub–30-nm resolution structural images and ?90-nm–resolution fluorescence images of several elements in frozen-hydrated green algae. This combined approach offers a way to study the role of trace elements in their structural context. PMID:25675478

Deng, Junjing; Vine, David J.; Chen, Si; Nashed, Youssef S. G.; Jin, Qiaoling; Phillips, Nicholas W.; Peterka, Tom; Ross, Rob; Vogt, Stefan; Jacobsen, Chris J.

2015-01-01

127

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

E-print Network

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

Walter, M.Todd

128

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - FIELD PORTABLE X-RAY FLUORESCENCE ANALYZER - SCITEC, MAP SPECTRUM ANALYZER  

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 (1) to determine how well FPXRF analyzers perform in comparison to standard reference...

129

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - FIELD PORTABLE X-RAY FLUORESCENCE ANALYZER - HNU SYSTEMS, SEFA-P  

EPA Science Inventory

In April 1995, the Environmental Protection Agency (EPA) conducted a demonstration of field portable X-ray fluorescence (FPXRF) Analyzers. The primary objectives of this demonstration were (1) to determine how well FPXRF analyzers perform in comparison to a standard reference m...

130

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 ...

131

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

132

Rapid screening for zinc deficiency using portable x-ray fluorescence in fingernails  

Technology Transfer Automated Retrieval System (TEKTRAN)

Elemental composition of fingernails is a useful indicator of micronutrient status and may reflect an individual’s intake over time. Our objective was to determine if portable X-ray fluorescence (XRF) is a viable method to assess zinc content in fingernails in the field. Human fingernail samples ran...

133

Determination of trace elements in bee honey, pollen and tissue by total reflection and radioisotope X-ray fluorescence spectrometry  

Microsoft Academic Search

Multielemental determinations in samples of various types of bee honey, pollen and bee tissue have been carried out using total reflection X-ray fluorescence spectrometry (TXRF) and radioisotope excited X-ray fluorescence spectrometry (XRF). The objective was to establish whether the elemental content of bee honey, in particular, correlates with any useful information about the environment, variety of honey, etc. An attempt

P. Kump; M. Ne?emer; J. Šnajder

1996-01-01

134

A High-Speed Detector System for X-ray Fluorescence Microprobes.  

SciTech Connect

We have developed a high-speed system for collecting x-ray fluorescence microprobe data, based on ASICs developed at BNL and high-speed processors developed by CSIRO. The system can collect fluorescence data in a continuous raster scan mode, and present elemental images in real time using Ryan's Dynamic Analysis algorithm. We will present results from a 32-element prototype array illustrating the concept. The final instrument will have 384 elements arranged in a square array around a central hole.

Siddons,P.D.; Dragone, A.; De Geronimo, g.; Kuczewski, A.; Kuczewski, J.; O

2006-10-29

135

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

1996-12-01

136

First use of portable system coupling X-ray diffraction and X-ray fluorescence for in-situ analysis of prehistoric rock art.  

PubMed

Study of prehistoric art is playing a major role in the knowledge of human evolution. Many scientific methods are involved in this investigation including chemical analysis of pigments present on artefacts or applied to cave walls. In the past decades, the characterization of coloured materials was carried on by taking small samples. This procedure had two main disadvantages: slight but existing damage of the paintings and limitation of the number of samples. Thanks to the advanced development of portable systems, in-situ analysis of pigment in cave can be now undertaken without fear for this fragile Cultural Heritage. For the first time, a portable system combining XRD and XRF was used in an underground and archaeological environment for prehistoric rock art studies. In-situ non-destructive analysis of black prehistoric drawings and determination of their composition and crystalline structure were successfully carried out. Original results on pigments used 13,000 years ago in the cave of Rouffignac (France) were obtained showing the use of two main manganese oxides: pyrolusite and romanechite. The capabilities of the portable XRD-XRF system have been demonstrated for the characterization of pigments as well as for the analysis of rock in a cave environment. This first in-situ experiment combining X-ray diffraction and X-ray fluorescence open up new horizons and can fundamentally change our approach of rock art studies. PMID:25127619

Beck, L; Rousselière, H; Castaing, J; Duran, A; Lebon, M; Moignard, B; Plassard, F

2014-11-01

137

Hard X-ray Fluorescence Measurements of Heteroepitaxial Solid Oxide Fuel Cell Cathode Materials  

SciTech Connect

Commonly, SOFCs are operated at high temperatures (above 800°C). At these temperatures expensive housing is needed to contain an operating stack as well as coatings to contain the oxidation of the metallic interconnects. Lowering the temperature of an operating device would allow for more conventional materials to be used, thus lowering overall cost. Understanding the surface chemical states of cations in the surface of the SOFC cathode is vital to designing a system that will perform well at lower temperatures. The samples studied were grown by pulsed laser deposition (PLD) at the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). 20% strontium doped lanthanum manganite (LSM-20) was grown on YSZ and NGO (neodymium gallate). The films on YSZ have a fiber texture. LSM-20 on NGO is heteroepitaxial. Lanthanum strontium cobalt ferrite (LSCF-6428) films were grown on LAO and YSZ with a GDC barrier layer. Total X-ray Reflection Fluorescence (TXRF) was used to depth profile the samples. In a typical experiment, the angle of the incident beam is varied though the critical angle. Below the critical angle, the x-ray decays as an evanescent wave and will only penetrate the top few nanometers. TXRF experiments done on LSM films have suggested strontium segregates to the surface and form strontium enriched nanoparticles (1). It should be pointed out that past studies have focused on 30% strontium A-site doping, but this project uses 20% strontium doped lanthanum manganite. XANES and EXAFS data were taken as a function of incoming angle to probe composition as a function of depth. XANES spectra can be difficult to analyze fully. For other materials density functional theory calculations compared to near edge measurements have been a good way to understand the 3d valence electrons (2).

Davis, Jacob N.; Miara, Lincoln J.; Saraf, Laxmikant V.; Kaspar, Tiffany C.; Gopalan, Srikanth; Pal, Uday B.; Woicik, Joseph C.; Basu, Soumendra N.; Ludwig, Karl F.

2012-12-01

138

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

139

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

140

Application of X-ray fluorescence analytical techniques in phytoremediation and plant biology studies  

NASA Astrophysics Data System (ADS)

Phytoremediation is an emerging technology that employs the use of higher plants for the clean-up of contaminated environments. Progress in the field is however handicapped by limited knowledge of the biological processes involved in plant metal uptake, translocation, tolerance and plant-microbe-soil interactions; therefore a better understanding of the basic biological mechanisms involved in plant/microbe/soil/contaminant interactions would allow further optimization of phytoremediation technologies. In view of the needs of global environmental protection, it is important that in phytoremediation and plant biology studies the analytical procedures for elemental determination in plant tissues and soil should be fast and cheap, with simple sample preparation, and of adequate accuracy and reproducibility. The aim of this study was therefore to present the main characteristics, sample preparation protocols and applications of X-ray fluorescence-based analytical techniques (energy dispersive X-ray fluorescence spectrometry—EDXRF, total reflection X-ray fluorescence spectrometry—TXRF and micro-proton induced X-ray emission—micro-PIXE). Element concentrations in plant leaves from metal polluted and non-polluted sites, as well as standard reference materials, were analyzed by the mentioned techniques, and additionally by instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). The results were compared and critically evaluated in order to assess the performance and capability of X-ray fluorescence-based techniques in phytoremediation and plant biology studies. It is the EDXRF, which is recommended as suitable to be used in the analyses of a large number of samples, because it is multi-elemental, requires only simple preparation of sample material, and it is analytically comparable to the most frequently used instrumental chemical techniques. The TXRF is compatible to FAAS in sample preparation, but relative to AAS it is fast, sensitive and multi-elemental. The micro-PIXE technique requires rather expensive instrumentation, but offers multi-elemental analysis on the tissue and cellular level.

Ne?emer, Marijan; Kump, Peter; Š?an?ar, Janez; Ja?imovi?, Radojko; Sim?i?, Jurij; Pelicon, Primož; Budnar, Miloš; Jeran, Zvonka; Pongrac, Paula; Regvar, Marjana; Vogel-Mikuš, Katarina

2008-11-01

141

X-ray fluorescence from the element with atomic number Z=120.  

PubMed

An atomic clock based on x-ray fluorescence yields has been used to estimate the mean characteristic time for fusion followed by fission in reactions 238U + 64Ni at 6.6??MeV/A. Inner shell vacancies are created during the collisions in the electronic structure of the possibly formed Z=120 compound nuclei. The filling of these vacancies accompanied by a x-ray emission with energies characteristic of Z=120 can take place only if the atomic transitions occur before nuclear fission. Therefore, the x-ray yield characteristic of the united atom with 120 protons is strongly related to the fission time and to the vacancy lifetimes. K x rays from the element with Z=120 have been unambiguously identified from a coupled analysis of the involved nuclear reaction mechanisms and of the measured photon spectra. A minimum mean fission time ?(f)=2.5×10(-18)??s has been deduced for Z=120 from the measured x-ray multiplicity. PMID:22540578

Frégeau, M O; Jacquet, D; Morjean, M; Bonnet, E; Chbihi, A; Frankland, J D; Rivet, M F; Tassan-Got, L; Dechery, F; Drouart, A; Nalpas, L; Ledoux, X; Parlog, M; Ciortea, C; Dumitriu, D; Fluerasu, D; Gugiu, M; Gramegna, F; Kravchuk, V L; Marchi, T; Fabris, D; Corsi, A; Barlini, S

2012-03-23

142

Hard X-rays and Fluorescent Iron Emission from the Embedded Infrared Cluster in NGC 2071  

E-print Network

We present first results of XMM-Newton X-ray observations of the infrared cluster lying near the NGC 2071 reflection nebula in the Orion B region. This cluster is of interest because it is one of the closest regions known to harbor embedded high-mass stars. We report the discovery of hard X-ray emission from the dense central NGC 2071-IR subgroup which contains at least three high-mass young stellar objects (NGC 2071 IRS-1, IRS-2, and IRS-3). A prominent X-ray source is detected within 1 arcsecond of the infrared source IRS-1, which is thought to drive a powerful bipolar molecular outflow. The X-ray spectrum of this source is quite unusual compared to the optically thin plasma spectra normally observed in young stellar objects (YSOs). The spectrum is characterized by a hard broad-band continuum plus an exceptionally broad emission line at approximately 6.4 keV from neutral or near-neutral iron. The fluorescent Fe line likely originates in cold material near the embedded star (i.e. a disk or envelope) that is irradiated by the hard heavily-absorbed X-ray source.

Stephen L. Skinner; Audrey E. Simmons; Marc Audard; Manuel Guedel

2006-12-19

143

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

144

Fast Differential Phase-Contrast Imaging and Total Fluorescence Yield Mapping in a Hard X-ray Fluorescence Microprobe  

NASA Astrophysics Data System (ADS)

We have incorporated differential phase-contrast (DPC) detection in a hard x-ray fluorescence microprobe at the Advanced Photon Source. We report a straightforward implementation of unidirectional DPC and demonstrate that it is highly advantageous for imaging low-Z specimens with hard x-rays (10keV). Phase-contrast imaging of a specimen can be used to acquire fast overview images of samples that allow more precise targeting of time consuming fluorescence scans. In order to get an overview of the elemental content of a specimen in these fly-scans, we have also implemented a fast detection of total fluorescence yield. Additionally, a DPC image of the specimen is obtained simultaneously with the fluorescence maps in normal step-scanning mode, to facilitate a direct comparison and co-registration with visible light micrographs.

Vogt, S.; Feser, M.; Legnini, D.; Kirz, J.; Maser, J.

2004-05-01

145

Optimizing detector geometry for trace element mapping by X-ray fluorescence.  

PubMed

Trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral response of energy dispersive detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. We conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples. PMID:25600825

Sun, Yue; Gleber, Sophie-Charlotte; Jacobsen, Chris; Kirz, Janos; Vogt, Stefan

2015-05-01

146

In-situ speciation of arsenic contaminated soil using micro-focused x-ray fluorescence and x-ray absorption fine  

E-print Network

In-situ speciation of arsenic contaminated soil using micro-focused x-ray fluorescence and x-A, 0-20 cm; LM-B, 20-40 cm) of a mixed metal-arsenic contaminated soil from a former copper chromated-contaminating metal cations (Cu, Zn, & Cr) in the solid phase speciation of arsenic. Elemental maps from ÝSXRF

Sparks, Donald L.

147

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...

148

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

NASA Astrophysics Data System (ADS)

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, Bärbel; Nickel, Bert

2005-09-01

149

Correlative organelle fluorescence microscopy and synchrotron X-ray chemical element imaging in single cells.  

PubMed

X-ray chemical element imaging has the potential to enable fundamental breakthroughs in the understanding of biological systems because chemical element interactions with organelles can be studied at the sub-cellular level. What is the distribution of trace metals in cells? Do some elements accumulate within sub-cellular organelles? What are the chemical species of the elements in these organelles? These are some of the fundamental questions that can be addressed by use of X-ray chemical element imaging with synchrotron radiation beams. For precise location of the distribution of the elements, identification of cellular organelles is required; this can be achieved, after appropriate labelling, by use of fluorescence microscopy. As will be discussed, this approach imposes some limitations on sample preparation. For example, standard immunolabelling procedures strongly modify the distribution of the elements in cells as a result of the chemical fixation and permeabilization steps. Organelle location can, however, be performed, by use of a variety of specific fluorescent dyes or fluorescent proteins, on living cells before cryogenic fixation, enabling preservation of element distribution. This article reviews the methods used for fluorescent organelle labelling and X-ray chemical element imaging and speciation of single cells. Selected cases from our work and from other research groups are presented to illustrate the potential of the combination of the two techniques. PMID:25023971

Roudeau, Stéphane; Carmona, Asuncion; Perrin, Laura; Ortega, Richard

2014-11-01

150

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

151

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

NASA Astrophysics Data System (ADS)

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; Bewer, Brian; Zhang, Honglin; Nichol, Helen; Thomlinson, Bill; Chapman, Dean

2010-06-01

152

Beam line for experiments with coherent soft x-rays  

SciTech Connect

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

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

1982-12-01

153

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

154

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. PMID:22228913

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

2011-01-01

155

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

156

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

157

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

158

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

159

Internal elemental imaging by scanning X-ray fluorescence microtomography at the hard X-ray microprobe beamline of the SSRF: Preliminary experimental results  

NASA Astrophysics Data System (ADS)

Synchrotron-based X-ray micro-fluorescence (?-SXRF) is a non-destructive analytical technique and has been widely used to detect and quantify the elemental composition of samples in their natural state. To determine the internal elemental distributions within samples, X-ray fluorescence microtomography has been developed based on the hard X-ray microprobe at beamline BL15U1 of the Shanghai Synchrotron Radiation Facility (SSRF) in Shanghai, China. This technique was applied to image the cross-sectional distributions of multiple elements within a single human hair, and its validity was evaluated by comparing the results with the elemental maps of a thin hair section obtained using the well-established ?-SXRF mapping method. Elemental images of S, Ca, Mn, Fe, Cu, and Zn within a virtual slice of the hair were reconstructed after the tomographic measurements. The tomographic images of heavy elements like Fe, Cu, and Zn were found to be in good agreement with the corresponding ?-SXRF maps. Light elements, such as S, however, represented different patterns due to non-negligible self-absorption in the sample, and sophisticated correction algorithms accounting for such effects are required for obtaining qualitatively and quantitatively more accurate images. Compared to ?-SXRF mapping, X-ray fluorescence microtomography reduces the sample preparation requirements and has been demonstrated in this work as being a more ideal and effective imaging modality to non-destructively mapping out the internal distribution of heavy elements within samples at the micrometer scale at the SSRF.

Qiu, Jingke; Deng, Biao; Yang, Qun; Yan, Fen; Li, Aiguo; Yu, Xiaohan

2011-11-01

160

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

161

Interpretation of heterogeneity effects in synchrotron X-ray fluorescence microprobe data  

PubMed Central

Heterogeneity effects often limit the accuracy of synchrotron X-ray fluorescence microprobe elemental analysis data to ± 30%. The difference in matrix mass absorption at K? and K? fluorescence energies of a particular element can be exploited to yield information on the average depth-position of the element or account for heterogeneity effects. Using this technique, the heterogeneous distribution of Cu in a simple layered sample could be resolved to a 2 × 2 × 10 (x, y, z, where z is the depth coordinate) micrometer scale; a depth-resolution limit was determined for the first transition metal series and several other elements in calcite and iron oxide matrices. For complex heterogeneous systems, determination of average element depth may be computationally limited but the influence of heterogeneity on fluorescence data may still be assessed. We used this method to compare solid-state diffusion with sample heterogeneity across the Ni-serpentine/calcite boundary of a rock from Panoche Creek, California. We previously reported that Ni fluorescence data may indicate solid state diffusion; in fact, sample heterogeneity in the depth dimension can also explain the Ni fluorescence data. Depth heterogeneity in samples can lead to misinterpretation of synchrotron X-ray microprobe results unless care is taken to account for the influence of heterogeneity on fluorescence data.

Zavarin, Mavrik; Doner, Harvey E

2002-01-01

162

Determination of fluorine by total reflection X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

There is a growing interest in determination of low Z elements, i.e. carbon to phosphorus, in various samples. Total reflection X-ray fluorescence spectrometry (TXRF) has been already established as a suitable trace element analytical method with low sample demand and quite good quantification limits. Recently, the determinable element range was extended towards Z = 6 (carbon). In this study, the analytical performance of the total reflection X-ray fluorescence spectrometry for determination of fluorine was investigated applying a spectrometer equipped with Cr-anode X-ray tube, multilayer monochromator, vacuum chamber, and a silicon drift detector (SDD) with ultra thin window was used. The detection limit for fluorine was found to be 5 mg L - 1 (equivalent to 10 ng absolute) in aqueous matrix. The linear range of the fluorine determination is between 15 and 500 mg L - 1 , within this range the precision is below 10%. The matrix effects of the other halogens (chlorine, bromine and iodine), and sulfate were also investigated. It has been established that the upper allowed concentration limit of the above interfering elements is 100, 200, 50 and 100 mg L - 1 for Cl, Br, I and sulfate, respectively. Moreover, the role of the pre-siliconization of the quartz carrier plate was investigated. It was found, that the presence of the silicone results in poorer analytical performance, which can be explained by the thicker sample residue and stronger self-absorption of the fluorescent radiation.

Tarsoly, G.; Óvári, M.; Záray, Gy.

2010-04-01

163

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

NASA Astrophysics Data System (ADS)

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 obtained simultaneous in situ water saturations and colloid concentrations on timescales of tens of seconds. We used this technique to study the transport of colloids consisting of Na and Ca Montmorillonite clays through a preferential flow path in uniform well-sorted sand. This flow path had both saturated and unsaturated zones that travel downward with time. We found that the Na colloids showed little retention in the sand, while the Ca colloids were retarded with respect to the wetting front. By comparing the results to those obtained by infiltrations with a Cd solute we find that the retention of the colloids seen in the unsaturated portion of the column was no greater than that seen in the saturated portion. We discussed the advantages and limitations of this X-ray fluorescence technique and the implications for colloid transport.

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

2006-12-01

164

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

165

STANDARD OPERATING PROCEDURES FOR MEASUREMENT OF LEAD IN PAINT USING THE SCITEC MAP-3 X-RAY FLUORESCENCE SPECTROMETER  

EPA Science Inventory

A portable X-ray fluorescence (XRF) procedure for quantatively measuring lead in paint in situ is described along with recommended QA/QC practices. he procedure was evaluated using calibration paint films over various substrates and with field samples. sing the K shell X-rays, a ...

166

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

167

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

168

Cancer diagnosis using a conventional x-ray fluorescence camera with a cadmium-telluride detector  

NASA Astrophysics Data System (ADS)

X-ray fluorescence (XRF) analysis is useful for mapping various atoms in objects. Bremsstrahlung X-rays are selected using a 3.0 mm-thick aluminum filter, and these rays are absorbed by indium, cerium and gadolinium atoms in objects. Then XRF is produced from the objects, and photons are detected by a cadmium-telluride detector. The K? photons are discriminated using a multichannel analyzer, and the number of photons is counted by a counter card. The objects are moved and scanned by an x-y stage in conjunction with a two-stage controller, and X-ray images obtained by atomic mapping are shown on a personal computer monitor. The scan steps of the x and y axes were both 2.5 mm, and the photon-counting time per mapping point was 0.5 s. We carried out atomic mapping using the X-ray camera, and K? photons from cerium and gadolinium atoms were produced from cancerous regions in nude mice.

Sato, Eiichi; Enomoto, Toshiyuki; Hagiwara, Osahiko; Abudurexiti, Abulajiang; Sato, Koetsu; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-10-01

169

X-ray optics for scanning fluorescence microscopy and other applications  

SciTech Connect

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 <1 to 10 {mu}m, using standard laboratory x-ray tubes. We are investigating mirror optics in the Kirkpatrick-Baez (K-B) configuration. K-B optics uses two curved mirrors mounted orthogonally along the optical axis. The first mirror provides vertical focus, the second mirror provides horizontal focus. We have used two types of mirrors: synthetic multilayers and crystals. Multilayer mirrors are used with lower energy radiation such as Cu K{alpha}. At higher energies such as Ag K{alpha}, silicon wafers are used in order to increase the incidence angles and thereby the photon collection efficiency. In order to increase the surface area of multilayers which reflects x-rays at the Bragg angle, we have designed mirrors with the spacing between layers graded along the optic axis in order to compensate for the changing angle of incidence. Likewise, to achieve a large reflecting surface with silicon, the wafers are placed on a specially designed lever arm which is bent into a log spiral by applying force at one end. In this way, the same diffracting angle is maintained over the entire surface of the wafer, providing a large solid angle for photon collection.

Ryon, R.W. [Lawrence Livermore National Lab., CA (United States); Warburton, W.K. [X-Ray Instrumentation Associates, Menlo Park, CA (United States)

1992-05-01

170

X-ray fluorescence analysis of cultural artefacts — Applications to the Czech heritage  

NASA Astrophysics Data System (ADS)

X-ray florescence analysis is an excellent non-destructive tool for analysing the elemental composition of materials in a wide range of works of art. The Department of Dosimetry and Application of Ionising Radiation at CTU-FNSPE has used radionuclide or X-ray tube excited energy dispersive X-ray fluorescence for many kinds of artefacts, including frescos, paintings, manuscripts, metal sculptures and other objects, ceramics, jewellery, various archaeological finds, etc. The method used is more or less "traditional", i.e., semiconductor spectrometry of excited X-rays, with some optional choices—capillary optics for collimation of exciting beams and two-dimensional scanning. The "hardware" complex is supplemented by techniques for estimating the depth distribution of measured elements, for suppressing surface effects, for in situ non-contact measurements, etc. Extending the measurable range to lighter elements and decreasing the detection limits is one of the achievements that has been attained by improving the instrumentation and techniques that are used. This paper gives a brief review of works carried out at the Department of Dosimetry and Application of Ionising Radiation at CTU-FNSPE.

Trojek, T.; Musílek, L.; ?echák, T.

2014-02-01

171

LabVIEW control software for scanning micro-beam X-ray fluorescence spectrometer.  

PubMed

Confocal micro-beam X-ray fluorescence microscope was constructed. The system was assembled from commercially available components - a low power X-ray tube source, polycapillary X-ray optics and silicon drift detector - controlled by an in-house developed LabVIEW software. A video camera coupled to optical microscope was utilized to display the area excited by X-ray beam. The camera image calibration and scan area definition software were also based entirely on LabVIEW code. Presently, the main area of application of the newly constructed spectrometer is 2-dimensional mapping of element distribution in environmental, biological and geological samples with micrometer spatial resolution. The hardware and the developed software can already handle volumetric 3-D confocal scans. In this work, a front panel graphical user interface as well as communication protocols between hardware components were described. Two applications of the spectrometer, to homogeneity testing of titanium layers and to imaging of various types of grains in air particulate matter collected on membrane filters, were presented. PMID:22483897

Wrobel, Pawel; Czyzycki, Mateusz; Furman, Leszek; Kolasinski, Krzysztof; Lankosz, Marek; Mrenca, Alina; Samek, Lucyna; Wegrzynek, Dariusz

2012-05-15

172

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

PubMed

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

Eveno, Myriam; Moignard, Brice; Castaing, Jacques

2011-10-01

173

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

174

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

175

Macro and micro full field x-ray fluorescence with an X-ray pinhole camera presenting high energy and high spatial resolution.  

PubMed

This work describes a tabletop (50 cm × 25 cm × 25 cm) full field X-ray pinhole camera (FF-XPC) presenting high energy- and high spatial-resolution. The FF-XPC consists of a conventional charge-coupled device (CCD) detector coupled, in a coaxial geometry, to a pinhole collimator of small diameter. The X-ray fluorescence (XRF) is induced on the samples with an external low-power X-ray tube. The use of the CCD as an energy dispersive X-ray detector was obtained by adopting a multi-image acquisition in single photon counting and by developing a processing algorithm to be applied in real-time to each of the acquired image-frames. This approach allowed the measurement of X-ray spectra with an energy resolution down to 133 eV at the reference value of 5.9 keV. The detection of the X-ray fluorescence through the pinhole-collimator allowed the two-dimensional elemental mapping of the irradiated samples. Two magnifications (M), determined by the relative sample-pinhole-CCD distances, are used in the present setup. A low value of M (equal to 0.35×) allows the macro-FF-XRF of large area samples (up to 4 × 4 cm(2)) with a spatial resolution down to 140 ?m; a large magnification (M equal to 6×) is used for the micro-FF-XRF of small area samples (2.5 × 2.5 mm(2)) with a spatial resolution down to 30 ?m. PMID:25284509

Romano, Francesco Paolo; Caliri, Claudia; Cosentino, Luigi; Gammino, Santo; Giuntini, Lorenzo; Mascali, David; Neri, Lorenzo; Pappalardo, Lighea; Rizzo, Francesca; Taccetti, Francesco

2014-11-01

176

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

PubMed

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

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

2012-02-01

177

Instrumentation and Analysis Software Development for X-Ray Microfluorescence Experiments at the 4B Beamline of Pohang Light Source-II  

NASA Astrophysics Data System (ADS)

The 4B beamline of the Pohang Light Source-II performs X-ray microfluorescence experiments together with X-ray microdiffraction experiments, which was upgraded from the old operating conditions of 2.5 GeV and 200 mA to 3.0 GeV and 400 mA. The X-ray microbeam for the microfluorescence experiments is focused to a FWHM size of about 2 ?m by adjusting a Kirkpatrick-Baez (KB) mirror system through a LabVIEW application for automatic beam focusing, in the same manner as in the X-ray microdiffraction experiments. A fluorescence detector collects X-ray fluorescence spectra with high-spatial resolution by two-dimensionally scanning a sample attached on an XYZ motorized stage about the focused microbeam. The scanning process is also performed by a LabVIEW application and the collected fluorescence spectra are saved in text format. A microfluorescence analysis software has been newly developed to obtain two-dimensional maps of elements composing a sample from fluorescence spectra. This paper introduces the instrumentation for X-ray microfluorescence experiments at the 4B beamline, describes the details of the developed microfluorescence analysis software, and reports its first analysis results.

Gil, Kyehwan; Duck Jang, Sung; Lim, Jae-Hong; Huang, Jung-Yun; Kim, Hae Koo

2013-10-01

178

AUTOMATIC PARTICULATE SULFUR MEASUREMENTS WITH A DICHOTOMOUS SAMPLER AND ON-LINE X-RAY FLUORESCENCE ANALYSIS  

EPA Science Inventory

An instrument is described which employs a dichotomous sampler to acquire fine particulate samples on a continuous tape filter. Analyses for elemental sulfur are performed immediately following acquisition using a sensitive X-ray fluorescence spectrometer. Sample sequencing, data...

179

The Mars-XRD Instrument for ExoMars: Combined X-Ray Diffraction and Fluorescence Measurements  

NASA Astrophysics Data System (ADS)

Mars-XRD is a combined X-ray diffractometer and fluorescence spectrometer to analyse the mineralogy and chemical composition of Mars. We present our initial investigation into its ability to identify minerals under representative conditions.

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

2011-03-01

180

Dual x-ray fluorescence spectrometer and method for fluid analysis  

DOEpatents

Disclosed are an X-ray fluorescence (SRF) spectrometer and method for on-site and in-line determination of contaminant elements in lubricating oils and in fuel oils on board a marine vessel. An XRF source block 13 contains two radionuclide sources 16, 17 (e.g. Cd 109 and Fe 55), each oriented 180 degrees from the other to excite separate targets. The Cd 109 source 16 excites sample lube oil flowing through a low molecular weight sample line 18. The Fe 55 source 17 excites fuel oil manually presented to the source beam inside a low molecular weight vial 26 or other container. Two separate detectors A and B are arranged to detect the fluorescent x-rays from the targets, photons from the analyte atoms in the lube oil for example, and sulfur identifying x-rays from bunker fuel oil for example. The system allows both automated in-line and manual on-site analysis using one set of signal processing and multi-channel analyzer electronics 34, 37 as well as one computer 39 and user interface 43.

Wilson, Bary W.; Shepard, Chester L.

2005-02-22

181

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

182

Measurement of plutonium in spent nuclear fuel by self-induced x-ray fluorescence  

SciTech Connect

Direct measurement of the plutonium content in spent nuclear fuel is a challenging problem in non-destructive assay. The very high gamma-ray flux from fission product isotopes overwhelms the weaker gamma-ray emissions from plutonium and uranium, making passive gamma-ray measurements impossible. However, the intense fission product radiation is effective at exciting plutonium and uranium atoms, resulting in subsequent fluorescence X-ray emission. K-shell X-rays in the 100 keV energy range can escape the fuel and cladding, providing a direct signal from uranium and plutonium that can be measured with a standard germanium detector. The measured plutonium to uranium elemental ratio can be used to compute the plutonium content of the fuel. The technique can potentially provide a passive, non-destructive assay tool for determining plutonium content in spent fuel. In this paper, we discuss recent non-destructive measurements of plutonium X-ray fluorescence (XRF) signatures from pressurized water reactor spent fuel rods. We also discuss how emerging new technologies, like very high energy resolution microcalorimeter detectors, might be applied to XRF measurements.

Hoover, Andrew S [Los Alamos National Laboratory; Rudy, Cliff R [Los Alamos National Laboratory; Tobin, Steve J [Los Alamos National Laboratory; Charlton, William S [Los Alamos National Laboratory; Stafford, A [TEXAS A& M; Strohmeyer, D [TEXAS A& M; Saavadra, S [ORNL

2009-01-01

183

Spontaneous soft x-ray fluorescence from a superlattice under Kossel diffraction conditions  

NASA Astrophysics Data System (ADS)

The present study gives the proof of principle of a technique that is an extension of Kossel diffraction both from crystals to superlattices and toward the soft x-ray region, allowing the characterization of the interfaces within a periodic structure. We measure the intensity of the Co L? and Mg K? characteristic fluorescence emissions from a Mg/Co superlattice upon soft x-ray excitation. The observation is made so that the angle between the sample surface and the detection direction is scanned around the first and second Bragg peaks of the fluorescence emissions. Clear modulations of the emitted intensities are observed and well reproduced by simulations based on the reciprocity theorem and assuming a perfect stack. The present work gives evidence that such a superlattice plays the role of an optical cavity for the spontaneous emission generated within the stack. This should also be the case for stimulated emission, which when combined with pumping free electron laser, will open the road to innovative x-ray distributed feedback lasers.

Jonnard, P.; Yuan, Y.-Y.; Le Guen, K.; André, J.-M.; Zhu, J.-T.; Wang, Z.-S.; Bridou, F.

2014-08-01

184

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

185

Basic principles of Synchrotron Radiation-Induced X-Ray Fluorescence (SRXRF)  

SciTech Connect

The characteristic x rays can be used as powerful analytical tools for qualitative and quantitative determination of the major, minor and trace composition of materials. X Ray Fluorescence (XRF) techniques used for almost four decade to solve many problems in basic, applied science, and in industry. The XRF techniques that were developed initially used crystal spectrometers, and are referred to in literature as Wavelength Dispersive (WD) techniques. These WD techniques are still used in many fields and have the merit of a excellent energy resolution that allows for the analysis of many elements while avoiding the overlapping of some fluorescence peaks. They are also particularly useful in a matrix that produces copious quantities of a particular radiation. The principal disadvantages of a WD system are the low efficiency of crystal and the reduced energy region in which crystal spectrometer can be used. In the 1960's, Solid State Detectors (SSD) were developed with energy resolution such that the Energy Dispersive XRF techniques could be developed. These SSD's overcame some of the limitations of the WD techniques. The most attractive characteristics of the EDXRF techniques are in their intrinsic multielemental and non destructive capabilities. The development of the high intensity, high brilliance Synchrotron Radiation (SR) sources have open the possibility to make microanalyses using the XRF techniques, increasing the interest of the scientific community for these techniques. In this paper the basic concepts of the XRF technique are reviewed taking in account the availability of the new sources of x rays. 32 refs., 7 figs.

Gigante, G.E. (Rome Univ. (Italy). Dipt. di Fisica); Hanson, A.L. (Brookhaven National Lab., Upton, NY (USA))

1990-05-01

186

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

SciTech Connect

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

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

2010-01-01

187

Hard X-ray Observation of Cygnus X-1 By the Marshall Imaging X-ray Experiment (MIXE2)  

NASA Technical Reports Server (NTRS)

The second generation of the Marshall Imaging X-ray Experiment (MIXE2) was flown from Fort Sumner, New Mexico on May 7-8, 1997. The experiment consists of coded-aperture telescope with a field of view of 1.8 degrees (FWHM) and an angular resolution of 6.9 arcminutes. The detector is a large (7.84x10(exp 4) sq cm) effective area microstrip proportional counter filled with 2.0x10(exp5) Pascals of xenon with 2% isobutylene. We present MIXE2 observation of the 20-80keV spectrum and timing variability of Cygnus X-1 made during balloon flight.

Minamitani, Takahisa; Apple, J. A.; Austin, R. A.; Dietz, K. L.; Koloziejczak, J. J.; Ramsey, B. D.; Weisskopf, M. C.

1998-01-01

188

Use of x-ray fluorescence and diffraction techniques in studying ancient ceramics of Sri Lanka  

NASA Astrophysics Data System (ADS)

Ceramics were produced for centuries in Sri Lanka for various purposes. Ancient ceramic articles such as pottery, bricks, tiles, sewer pipes, etc, were made from naturally occurring raw materials. Use of X-ray fluorescence (XRF), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) in characterizing of two ancient ceramic samples from two different archaeological sites in Sri Lanka is presented. The information obtained in this manner is used to figure out the ancient ceramic technology, particularly to learn about the raw materials used, the source of raw materials, processing parameters such as firing temperature or binders used in ceramic production. This information then can be used to explore the archaeometric background such as the nature and extent of cultural and technological interaction between different periods of history in Sri Lanka.

Karunaratne, B. S. B.

2012-07-01

189

In Vivo X-Ray Fluorescence Microtomographic Imaging of Elements in Single-Celled Fern Spores  

SciTech Connect

We have observed in vivo three-dimensional distributions of constituent elements of single-celled spores of the fern Adiantum capillus-veneris using an X-ray fluorescence computed microtomography method. The images of these distributions are generated from a series of slice data, each of which is acquired by a sample translation-rotation method. An incident X-ray microbeam irradiates the sample with a spot size of 1 {mu}m. The high Ca concentration in the testa and the localized and overlapping Fe and Zn concentrations inside the spore are shown in three-dimensional images. The K concentration is high throughout the cell, and there are localized regions of higher density. The atomic number densities of these elements in the testa and inside the cell in a tomographic slice are estimated with a resolution of about 1 {mu}m.

Hirai, Yasuharu; Yoneyama, Akio; Hisada, Akiko [Advanced Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395 (Japan); Uchida, Kenko [Central Research Laboratory, Hitachi, Ltd., Kokubunji, Tokyo 185-8601 (Japan)

2007-01-19

190

3D imaging of transition metals in the zebrafish embryo by X-ray fluorescence microtomography.  

PubMed

Synchrotron X-ray fluorescence (SXRF) microtomography has emerged as a powerful technique for the 3D visualization of the elemental distribution in biological samples. The mechanical stability, both of the instrument and the specimen, is paramount when acquiring tomographic projection series. By combining the progressive lowering of temperature method (PLT) with femtosecond laser sectioning, we were able to embed, excise, and preserve a zebrafish embryo at 24 hours post fertilization in an X-ray compatible, transparent resin for tomographic elemental imaging. Based on a data set comprised of 60 projections, acquired with a step size of 2 ?m during 100 hours of beam time, we reconstructed the 3D distribution of zinc, iron, and copper using the iterative maximum likelihood expectation maximization (MLEM) reconstruction algorithm. The volumetric elemental maps, which entail over 124 million individual voxels for each transition metal, revealed distinct elemental distributions that could be correlated with characteristic anatomical features at this stage of embryonic development. PMID:24992831

Bourassa, Daisy; Gleber, Sophie-Charlotte; Vogt, Stefan; Yi, Hong; Will, Fabian; Richter, Heiko; Shin, Chong Hyun; Fahrni, Christoph J

2014-09-01

191

Reverse engineering the ancient ceramic technology based on X-ray fluorescence spectromicroscopy  

SciTech Connect

We present results of X-ray fluorescence (XRF) microprobe analyses of ancient ceramic cross-sections aiming at deciphering the different firing protocols used for their production. Micro-focused XRF elemental mapping, Fe chemical mapping and Fe K-edge X-ray absorption near edge structure spectroscopy were performed on pre-sigillata ceramics from southern Gaul, and terra Sigillata vessels from Italy and southern Gaul. Pieces from the different workshops and regions showed significant difference in the starting clay material, clay conditioning and kiln firing condition. By contrast, sherds from the same workshop exhibited more subtle differences and possible misfirings. Understanding the precise firing conditions and protocols would allow recreation of kilns for various productions. Furthermore, evolution and modification of kiln design would shed some light on how ancient potters devised solutions to diverse technological problems they encountered.

Sciau, Philippe; Leon, Yoanna; Goudeau, Philippe; Fakra, Sirine C.; Webb, Sam; Mehta, Apurva

2011-07-06

192

ROLE OF X-RAY FLUORESCENCE IN A MODERN GEOCHEMICAL LABORATORY.  

USGS Publications Warehouse

Because modern geochemical laboratories can seldom have all new analytical equipment, it is clear that priorities must be assigned and choices made when selecting each new instrument. X-ray fluorescence (XRF) spectroscopy has come to play a vital role in this environment largely because it is a dependable, multielement, rapid method that covers a wide range of elemental concentrations, commonly with only one sample preparation. The following discussion centers on the role of modern XRF instrumentation in the resolution of geochemical problems. In order to present a comprehensive view of this role, this paper draws upon a great deal of information from numerous X-ray laboratories visited in the United States and Canada.

Taggart, Joseph E.

1985-01-01

193

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

194

Elemental investigation on Spanish dinosaur bones by x-ray fluorescence  

NASA Astrophysics Data System (ADS)

In this paper we examine the chemical composition results obtained on a collection of 18 dinosaur fossil bones from Spain studied using a portable x-ray fluorescence spectrometer together with a reverse Monte Carlo numerical technique of data analysis. This approach is applied to the hypothesis of arbitrarily rough surfaces in order to account for the influence of the surface state of specimens on the chemical content evaluation. It is confirmed that the chemical content of elements is essential for understanding the changes brought about by diagenetic and taphonomic processes. However, for precise knowledge of what changes fossil bones have undergone after animal life and burial, it is necessary to use a multi-technique approach making use of other instruments like x-ray diffraction in order to describe accurately the transformations undergone by the mineralogical and bioinorganic phases and the properties of specific molecular groups.

Brunetti, Antonio; Piga, Giampaolo; Lasio, Barbara; Golosio, Bruno; Oliva, Piernicola; Stegel, Giovanni; Enzo, Stefano

2013-07-01

195

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

196

Preliminary investigation of trace element in Pterygium using Synchrotron radiation micro-beam X-ray fluorescence analysis (-XRF)  

NASA Astrophysics Data System (ADS)

We have assessed the relative content and distribution of Iron and Zinc elements using microbeam synchrotron radiation X-ray fluorescence technique. One such technique is X-ray fluorescence (XRF), which has been used previously to map trace elements distribution in Physical samples. In this article a compromise is suggested in issue Pterygium samples. In this study, a prospective randomized clinical trial was conducted. Serial frozen sections of pterygium tissues and conjunctival tissues of 40 ?m thickness were collected from 8 patients £¨10 eyes£©undergoing pterygium excision combine with limbal stem cell transplantation. A synchrotron-based XRF microprobe was used to map the distribution of Fe and Zn in whole frozen pterygium sections. The frozen sections were tested by synchrotron radiation X-ray fluorescence technique. These experiments were performed at BL15U in Shanghai, China. Then, the results have palyed that Iron and Zinc were present in both pterygium tissues and normal conjunctiva tissues (relevance ratio 100%). The contents of Iron and Zinc in normal conjunctiva tissues were significantly lower than in pterygium tissues (P < 0.05). The microelements were mostly clusteredin the pterygium tissues, while sparsely distributed in the normal conjunctiva tissue. Finally, we found that XRF imaging will be useful for mapping elemental distribution in Pterygium tissues. 40 ?m frozen section on 6 ?m mylar film is good for the test on BL15U. The contents of Iron and Zinc in pterygium tissue were significantly higher than in the control tissues. The results seem to be valuable in that Iron and Zinc may play a role in the development process of Pterygium.

Xie, Q.; Peng, L.; Cai, F.; Li, Ai G.; Yang, K.

2013-07-01

197

L-shell x-ray fluorescence computed tomography (XFCT) imaging of Cisplatin  

NASA Astrophysics Data System (ADS)

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.

Bazalova, Magdalena; Ahmad, Moiz; Pratx, Guillem; Xing, Lei

2014-01-01

198

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

199

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. PMID:22210307

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

2012-01-01

200

L-shell x-ray fluorescence computed tomography (XFCT) imaging of Cisplatin  

PubMed Central

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-cm 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 ?g/mL 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 (FBP) and with iterative maximum-likelihood expectation maximization (ML-EM) without and with attenuation correction. While K-shell XFCT was capable of providing 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 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 ?g/mg 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

201

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. PMID:23718594

Fu, Geng; Meng, Ling-Jian; Eng, Peter; Newville, Matt; Vargas, Phillip; Riviere, Patrick La

2013-01-01

202

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

203

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

204

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

205

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

206

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

Microsoft Academic Search

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

Tatsuaki Okada

2010-01-01

207

X-ray based extensometry  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

208

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

209

The Bionanoprobe: hard X-ray fluorescence nanoprobe with cryogenic capabilities  

PubMed Central

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

210

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

211

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

212

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

213

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

214

In-vivo Fluorescent X-ray CT Imaging of Mouse Brain  

SciTech Connect

Using a non-radioactive iodine-127 labeled cerebral perfusion agent (I-127 IMP), fluorescent X-ray computed tomography (FXCT) clearly revealed the cross-sectional distribution of I-127 IMP in normal mouse brain in-vivo. Cerebral perfusion of cortex and basal ganglion was depicted with 1 mm in-plane spatial resolution and 0.1 mm slice thickness. Degree of cerebral perfusion in basal ganglion was about 2-fold higher than that in cortical regions. This result suggests that in-vivo cerebral perfusion imaging is realized quantitatively by FXCT at high volumetric resolution.

Takeda, T.; Wu, J.; Lwin, Thet-Thet; Huo, Q.; Minami, M. [Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575 (Japan); Sunaguchi, N.; Murakami, T.; Mouri, S.; Nasukawa, S.; Yuasa, T.; Akatsuka, T. [Faculty of Engineering, Yamagata University, Yonezawa, Yamagata 992-8510 (Japan); Hyodo, K. [Institute of Material Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Hontani, H. [Department of Computer Science and Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555 (Japan)

2007-01-19

215

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

216

Synchrotron total reflection X-ray fluorescence at BL-16 microfocus beamline of Indus-2  

SciTech Connect

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., E-mail: mktiwari@rrcat.gov.in; Singh, A. K., E-mail: mktiwari@rrcat.gov.in; Das, Gangadhar, E-mail: mktiwari@rrcat.gov.in; Chowdhury, Anupam, E-mail: mktiwari@rrcat.gov.in; Lodha, G. S., E-mail: mktiwari@rrcat.gov.in [Indus Synchrotrons Utilisation Division, Raja Ramanna Centre for Advanced Technology, Indore-452013 (India)

2014-04-24

217

A dosimetry study for a K-fluorescent x-ray system  

E-print Network

-ray therapy unit as the primary source of radiation. The K-fluorescenc. e radiator targets used were copper, tin, tantalum and lead sheets. The existence of the K-fluorescent beams was confirmed by half value layer measurements and by the analysis of energy... adaptability to being used for such applications as radiation detection instrument calibration and radiation biology studies. The X-ray therapy unit in the Radiological Safety Laboratory, Texas A&M University, was used as the source for the primary X...

Beard, Travis Newton

1975-01-01

218

Analysis Results for Lunar Soil Simulant Using a Portable X-Ray Fluorescence Analyzer  

NASA Technical Reports Server (NTRS)

Lunar soil will potentially be used for oxygen generation, water generation, and as filler for building blocks during habitation missions on the Moon. NASA s in situ fabrication and repair program is evaluating portable technologies that can assess the chemistry of lunar soil and lunar soil simulants. This Technical Memorandum summarizes the results of the JSC 1 lunar soil simulant analysis using the TRACeR III IV handheld x-ray fluorescence analyzer, manufactured by KeyMaster Technologies, Inc. The focus of the evaluation was to determine how well the current instrument configuration would detect and quantify the components of JSC-1.

Boothe, R. E.

2006-01-01

219

The determination of nanogram amounts of Chromium in urine by x-ray fluorescence spectroscopy  

USGS Publications Warehouse

Nanogram amounts of chromium can be extracted as oxinate into chloform. By treatment of the chloroform layer 3 M hydrochloric acid, oxinates of other elements and excess of reagent are removed, leaving a chloroform solution of the chromium chelate only. This solution is concentrated and transferred to the top of a small brass rod acting as sample holder. The intensity of the X-ray fluorescence of the Cr K?? line is measured with curved crystal optics. Chromium amounts greater than 5 ng can be detected. The application of the procedure to the analysis of the chromium content of urine is demonstrated. ?? 1969.

Beyermann, K.; Rose, H.J., Jr.; Christian, R.P.

1969-01-01

220

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

221

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

222

Determination of wear metals in used lubricating oils by X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

Application of an X-ray fluorescence analytical procedure for the determination of wear metals in used lubricating oils is described. Oil saoples were collected from UH-IH type helicopter engines at regular intervals and subjected to chemical peatreatment in order to remove the high viscosity of the oil and particle size effects. The procedure was used to determine the concentration of topper and iron wear metals in oils. They were found to increase with engine operating time. The results obtained show that the XRFS procedure provides a better indication of impending machine failure than conventional methods.

Zararsiz, A.; Kirmaz, R.; Arikan, P.

1996-03-01

223

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

PubMed

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

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

2013-04-10

224

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

225

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

226

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

227

X-ray fluorescence imaging system for fast mapping of pigment distributions in cultural heritage paintings  

NASA Astrophysics Data System (ADS)

Conventional X-ray fluorescence imaging technique uses a focused X-ray beam to scan through the sample and an X-ray detector with high energy resolution but no spatial resolution. The spatial resolution of the image is then determined by the size of the exciting beam, which can be obtained either from a synchrotron source or from an X-ray tube with a micro-capillary lens. Such a technique based on a pixel-by-pixel measurement is very slow and not suitable for imaging large area samples. The goal of this work is to develop a system capable of simultaneous imaging of large area samples by using a wide field uniform excitation X-ray beam and a position sensitive and energy dispersive detector. The development is driven by possible application of such a system to imaging of distributions of hidden pigments containing specific elements in cultural heritage paintings, which is of great interest for the cultural heritage research. The fluorescence radiation from the area of 10 × 10 cm2 is projected through a pinhole camera on the Gas Electron Multiplier detector of the same area. The detector is equipped with two sets of orthogonal readout strips. The strips are read out by the GEMROC Application Specific Integrated Circuits (ASIC)s, which deliver time and amplitude information for each hit. This ASIC architecture combined with a Field Programmable Gate Array (FPGA) based readout system allows us to reconstruct the position and the total energy of each detected photon for high count rates up to 5 × 106 cps. Energy resolution better than 20% FWHM for the 5.9 keV line and spatial resolution of 1 mm FWHM have been achieved for the prototype system. Although the energy resolution of the Gas Electron Multiplier (GEM) detector is, by principle, not competitive with that of specialised high energy resolution semiconductor detectors, it is sufficient for a number of applications. Compared to conventional micro-XRF techniques the developed system allows shortening of the measurement time by 2-3 orders of magnitude.

Zieli?ska, A.; D?browski, W.; Fiutowski, T.; Mindur, B.; Wi?cek, P.; Wróbel, P.

2013-10-01

228

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. 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.

2011-01-01

229

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

NASA Astrophysics Data System (ADS)

The ESA/NASA ExoMars mission, due for launch in 2018, has a combined X-ray fluorescence/diffraction instrument, Mars-XRD, as part of the onboard analytical laboratory. The results of some XRF (X-ray fluorescence) and XRD (X-ray diffraction) tests using a laboratory chamber with representative performance are reported. A range of standard geological reference materials and analogues were used in these tests. The XRD instruments are core components of the forthcoming NASA Mars Science Laboratory (MSL) and ESA/NASA ExoMars missions and will provide the first demonstrations of the capabilities of combined XRD/XRF instrumentation in situ on an extraterrestrial planetary surface. The University of Leicester team is part of the Italy-UK collaboration that is responsible for building the ExoMars X-ray diffraction instrument, Mars-XRD [1,2]. Mars-XRD incorporates an Fe-55 radioisotope source and three fixed-position charge-coupled devices (CCDs) to simultaneously acquire an X-ray fluorescence spectrum and a diffraction pattern providing a measurement of both elemental and mineralogical composition. The CCDs cover an angular range of 2? = 6° to 73° enabling the analysis of a wide range of geologically important minerals including phyllosilicates, feldspars, oxides, carbonates and evaporites. The identification of hydrous minerals may help identify past Martian hydrothermal systems capable of preserving traces of life. Here we present some initial findings from XRF and XRD tests carried out at the University of Leicester using an Fe-55 source and X-ray sensitive CCD. The XRF/XRD test system consists of a single CCD on a motorised arm, an Fe-55 X-ray source, a collimator and a sample table which approximately replicate the reflection geometry of the Mars-XRD instrument. It was used to test geological reference standard materials and Martian analogues. This work was funded by the Science and Technology Facilities Council, UK. References [1] Marinangeli, L., Hutchinson, I., Baliva, A., Stevoli, A., Ambrosi, R., Critani, F., Delhez, R., Scandelli, L., Holland, A., Nelms, N. & the Mars-XRD Team, Proceedings of the 38th Lunar and Planetary Science Conference, 12 - 16 March 2007, League City, Texas, USA. [2] L. Marinangeli, I. B. Hutchinson, A. Stevoli, G. Adami, R. Ambrosi, R. Amils, V. Assis Fernandes, A. Baliva, A. T. Basilevsky, G. Benedix, P. Bland, A. J. Böttger, J. Bridges, G. Caprarelli, G. Cressey, F. Critani, N. d'Alessandro, R. Delhez, C. Domeneghetti, D. Fernandez-Remolar, R. Filippone, A. M. Fioretti, J. M. Garcia Ruiz, M. Gilmore, G. M. Hansford, G. Iezzi, R. Ingley, M. Ivanov, G. Marseguerra, L. Moroz, C. Pelliciari, P. Petrinca, E. Piluso, L. Pompilio, J. Sykes, F. Westall and the MARS-XRD Team, EPSC-DPS Joint Meeting 2011, 3 - 7 October 2011, La Cité Internationale des Congrès Nantes Métropole, Nantes, France.

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

2011-12-01

230

Marshall Space Flight Center imaging x-ray experiment (MIXE)  

NASA Astrophysics Data System (ADS)

The MIXE includes a state-of-the-art imaging proportional counter which utilizes fluorescence gating in order to achieve high sensitivity in the bandwidth from the xenon k-edge (35 keV) to 100 keV. The current detector system includes a parallel amplification stage to allow for improved energy resolution without sacrificing spatial resolution. Another novel feature is the molybdenum/stainless steel pressure vessel, which is an important factor in achieving low background rates. In this paper we compare the results of Monte Carlo simulations with laboratory experiments and present data obtained during a recent balloon flight from Palestine, Texas.

Ramsey, Brian D.; Apple, J. A.; Dietz, Kurtis L.; Weisskopf, Martin C.; Austin, Robert A.; Kolodziejczak, Jeffery J.; Minamitani, Takahisa

1993-11-01

231

[Application of internal standard to analysis of the metal Ni element in soils by X-ray fluorescence spectroscopy].  

PubMed

We quantitatively analyzed the content of the element Ni in the national standard soil samples by the method of X-ray fluorescence spectroscopy through using EDXRF metal experimental platform in ambient environment of the laboratory. Studying the characteristics of X-ray fluorescence of element Ni in the experiment, the calibration curve of element Ni was measured by using the adding internal standard method and the method of how to select the internal standard element was analysed according to the experimental results. The experimental results demonstrate that the matrix suitable element can be selected as the internal standard element to analyse the soil samples; using Pb L(alpha) line, Cu, Fe and K(alpha) lines as internal standard lines, the relative deviation of element from the standard value is 6.24%, 5.24% and 5.22%, which indicates that selecting the appropriate characteristic line of the matrix major element as the internal standard line can effectively improve measurement accuracy of the results. PMID:22715799

Zhang, Wei; Zhang, Yu-jun; Chen, Dong; Liu, Jing; Wang, Chun-long; Zhang, Rong; Zhao, Nan-jing; Liu, Wen-qing

2012-04-01

232

Non-destructive in situ study of "Mad Meg" by Pieter Bruegel the Elder using mobile X-ray fluorescence, X-ray diffraction and Raman spectrometers  

NASA Astrophysics Data System (ADS)

"Mad Meg", a figure of Flemish folklore, is the subject of a famous oil-on-panel painting by the Flemish renaissance artist Pieter Bruegel the Elder, exhibited in the Museum Mayer van den Bergh (Antwerp, Belgium). This article reports on the in situ chemical characterization of this masterpiece by using currently available state-of-the-art portable analytical instruments. The applied non-destructive analytical approach involved the use of a) handheld X-ray fluorescence instrumentation for retrieving elemental information and b) portable X-ray fluorescence/X-ray diffraction instrumentation and laser-based Raman spectrometers for obtaining structural/molecular information. Next to material characterization of the used pigments and of the different preparation layers of the painting, also the verification of two important historical iconographic hypotheses is performed concerning the economic way of painting by Brueghel, and whether or not he used blue smalt pigment for painting the boat that appears towards the top of the painting. The pigments identified are smalt pigment (65% SiO2 + 15% K2O + 10% CoO + 5% Al2O3) for the blue color present in all blue areas of the painting, probably copper resinate for the green colors, vermillion (HgS) as red pigment and lead white is used to form different colors. The comparison of blue pigments used on different areas of the painting gives no differences in the elemental fingerprint which confirms the existing hypothesis concerning the economic painting method by Bruegel.

Van de Voorde, Lien; Van Pevenage, Jolien; De Langhe, Kaat; De Wolf, Robin; Vekemans, Bart; Vincze, Laszlo; Vandenabeele, Peter; Martens, Maximiliaan P. J.

2014-07-01

233

[Simultaneous determination of multiple elements in airborne particulate samples by X-ray fluorescence spectrometry].  

PubMed

An energy dispersive X-ray fluorescence spectrometer (EDX) has been applied to determine multielements in the workplace air. The standards for X-ray fluorescence analysis were prepared by the chelate precipitation method on polyvinyl chloride (PVC) membrane filter. And, the specimens were prepared to deposit various metal compounds of different chemical forms by the suspension method on PVC membrane filter, and they were determined with EDX and atomic absorption spectrometer (AAS). The results obtained were as follows. Though there is a difference by each element, an amount less than 3 microgram/cm2 per unit area makes it possible to undergo multielement analysis, that is, is has no influence on fine particle effect (particle size; under 5 microns). Then, effects of the X-ray intensity by different chemical forms are negligible. At the presence the neighboring element and other elements this technique showed greater precision by carrying out on corrective treatment, etc. The coefficient of variation of this technique was in the range of 2.5-6.5% at DDTC-Cu of 0.5-5.0 micrograms/cm2, with the limit of detection for As : 0.002 microgram/cm2, Zn : 0.003 microgram/cm2, Pb : 0.003 microgram/cm2, Cu : 0.004 microgram/cm2, Ni : 0.003 microgram/cm2, Fe : 0.005 microgram/cm2, Mn : 0.008 microgram/cm2, Cr : 0.013 microgram/cm2, respectively. Aerosols collected at the workplace were analyzed with EDX and AAS, and the obtained results showed good agreement with such regression line as y = 1.04 chi + 0.04, the coefficient of correlation being r = 0.995. From these results, this technique was found to be a very excellent method for monitoring of multielements in the workplace air. PMID:6663820

Takada, T; Hitosugi, M; Kadowaki, T; Kudo, M

1983-07-01

234

Investigation by laser induced breakdown spectroscopy, X-ray fluorescence and X-ray powder diffraction of the chemical composition of white clay ceramic tiles from Veliki Preslav  

NASA Astrophysics Data System (ADS)

The paper presents the results of the application of laser induced breakdown spectroscopy, X-ray fluorescence spectrometry, and X-ray powder diffraction in assessing the chemical and phase composition of white clay decorative ceramic tiles from the medieval archaeological site of Veliki Preslav, a Bulgarian capital in the period 893-972 AC, well-known for its original ceramic production. Numerous white clay ceramic tiles with highly varied decoration, produced for wall decoration of city's churches and palaces, were found during the archaeological excavations in the old capital. The examination of fourteen ceramic tiles discovered in one of the city's monasteries is aimed at characterization of the chemical profile of the white-clay decorative ceramics produced in Veliki Preslav. Combining different methods and comparing the obtained results provides complementary information regarding the white-clay ceramic production in Veliki Preslav and complete chemical characterization of the examined artefacts.

Blagoev, K.; Grozeva, M.; Malcheva, G.; Neykova, S.

2013-01-01

235

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

236

The energetic X-ray imaging telescope experiment (EXITE)  

SciTech Connect

A new position-sensitive scintillation detector (NaI(Tl)), coded mask, and precision pointing system (less than or equal to 1 arcmin) are being developed for balloon-borne imaging and spectral studies of cosmic x-ray sources in the 20-300 keV band. The scientific objectives of EXITE as well as the general design of the detector, telescope and balloon gondola systems are presented.

Grindlay, J.E.; Garcia, M.R.; Burg, R.I.; Murray, S.S.

1986-02-01

237

Case Studies on Facility Characterization with X-Ray Fluorescence Spectrometry  

SciTech Connect

A hand-held x-ray fluorescence (XRF) analyzer is being used to characterize facilities in support of demolition activities at the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee. Approximately 500 facilities at the U.S. Department of Energy site are being demolished under the ETTP Decontamination and Decommissioning (D and D) project. Facility characterization is being conducted to provide data for waste profiling and identify hazards to demolition workers. XRF spectrometry is a non-destructive analytical technique used to identify and quantify the elemental composition of a substance based on the intensity of its characteristic X-ray emission wavelength or energy. The Innov-X Systems{sup R} Model XT-245S XRF analyzer used at ETTP is equipped with a silver anode x-ray tube and a Si PIN diode detector. X-rays are generated by electrical current, eliminating the need for radioactive isotopes. Electronic components can be powered by either a lithium-ion battery or an A/C adapter, and the instrument is controlled by an iPAQ{sup R} pocket personal computer. The unit has two primary operating modes. Alloy analysis mode measures percent levels of elements in metals such as a pipes, valves, equipment, or construction materials. Soil mode provides parts-per-million (ppm) quantities in bulk solids like concrete dust, residue, paint chips, or soil. The hand-held unit can analyze material in place, or it can analyze samples in a test stand by remote operation. This paper present some case studies demonstrating a variety of XRF applications for facility characterization: Metal Materials Characterization, Lead Paint Identification, Hot Spot Delineation, Bulk Solids Testing. XRF has been the analytical technique of choice for identifying metal alloy components and has also been useful in analyzing bulk materials. Limitations of XRF testing include the inability to directly analyze elements with low atomic weights. Light elements such as beryllium and aluminum do not emit characteristic x-rays that the instrument can detect. However, process knowledge and existing historical data can be used to evaluate the presence of beryllium, which has been widely characterized at ETTP using industrial hygiene smear samples. Aluminum can be indirectly measured in aluminum alloys using x-ray scatter lines. The Innov-X Systems XRF has a light elements setting that employs this method, and it has been widely used on the ETTP D and D project. Another potential limitation involves analyzing samples that are radioactive, or analyzing samples in a radioactive environment. Radiation (including gamma, beta, and high energy alpha particles) acts as another excitation mechanism to create x-rays from materials being analyzed. Samples analyzed under those conditions will absorb more x-rays than just those emitted by the instrument silver anode tube, resulting in a potential high bias. This type of interference is identified by radiological surveys and minimized by relocating measurements to areas of lower activity when feasible.

Kirk, K.T.; Brooksbank, R.D.; Meszaros, J.M.; Towery, W.E. [Bechtel Jacobs Company LLC: P.O. Box 4699, Oak Ridge, Tennessee, 37831-7405 (United States)

2008-01-15

238

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

239

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, São 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.

Leitão, 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

240

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

241

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

SciTech Connect

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 metals showed that metal element As is few. The dinosaur most likely belongs to natural death. This is different from Zigong dinosaurs which were found dead from poisoning. This method has been used to find that metals Fe and Mn are accrete, and the same is true for Sr and Y. This study indicated that colloid granule Fe and Mn, as well as Sr and Y had opposite electric charges in lithification process of fossils. By this analysis, compound forms can be ascertained. Synchrotron light source x-ray fluorescence is a complementary method that shows mapping of metal elements at the dinosaur fossil, and is rapid, exact and intuitionist. This study shows that dinosaur fossil mineral imaging has a potential in reconstructing the paleoenvironment and ancient geology.

Wang, Y.; Qun, Y; Ablett, J

2008-01-01

242

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

243

Optical fluorescence and X-ray fluorescence endoscopic imaging – Comparison and basic investigations  

Microsoft Academic Search

In the field of minimal invasive medicine, endoscopic imaging is an essential feature of diagnostics and process controls. For minimal invasive procedures (in addition to normal visus) it often is important to record elements of the so-called functional imaging. Recent developments in the technology of capillary-fiber optics suitable for X-rays in the range of approximately 4–10keV point to the possible

Jürgen Beuthan; Cathrin Dressler; Michael Haschke; Frank Wacker

2006-01-01

244

Multi-Color Soft X-ray Diagnostic Design for the Levitated Dipole Experiment (LDX)  

E-print Network

Multi-Color Soft X-ray Diagnostic Design for the Levitated Dipole Experiment (LDX) M.S. Davis, D a design for a new diagnostic to measure the warm plasma electron temperature on LDX using a `multi-color

245

Medieval glass from the Cathedral in Paderborn: a comparative study using X-ray absorption spectroscopy, X-ray fluorescence, and inductively coupled laser ablation mass spectrometry  

NASA Astrophysics Data System (ADS)

We have investigated four stained glass samples recovered from an archaeological excavation at the Cathedral in Paderborn (Germany) between 1978 and 1980. On two of the samples there are parts of paintings. Concentrations of major elements were determined using two independent techniques: LA-ICP-MS (a UV laser ablation microsampler combined with an inductively coupled plasma mass spectrometer) and synchrotron radiation X-ray excited X-ray fluorescence (SR-XRF). The SR-XRF data were quantified by using the program package PyMCA developed by the software group of the ESRF in Grenoble. Significant differences were found between the concentrations determined by the two techniques that can be explained by concentration gradients near the surface of the glasses caused, for example, by corrosion/leaching processes and the different surface sensitivities of the applied techniques. For several of the elements that were detected in the glass and in the colour pigments used for the paintings X-ray absorption near edge structure (XANES) spectra were recorded in order to determine the chemical speciation of the elements of interest. As was expected, most elements in the glass were found as oxides in their most stable form. Two notable exceptions were observed: titanium was not found as rutile—the most stable form of TiO2—but in the form of anatase, and lead was not found in one defined chemical state but as a complex mixture of oxide, sulphate, and other compounds.

Hormes, J.; Roy, A.; Bovenkamp, G.-L.; Simon, K.; Kim, C.-Y.; Börste, N.; Gai, S.

2013-04-01

246

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

247

Combined evaluation of grazing incidence X-ray fluorescence and X-ray reflectivity data for improved profiling of ultra-shallow depth distributions  

NASA Astrophysics Data System (ADS)

The continuous downscaling of the process size for semiconductor devices pushes the junction depths and consequentially the implantation depths to the top few nanometers of the Si substrate. This motivates the need for sensitive methods capable of analyzing dopant distribution, total dose and possible impurities. X-ray techniques utilizing the external reflection of X-rays are very surface sensitive, hence providing a non-destructive tool for process analysis and control. X-ray reflectometry (XRR) is an established technique for the characterization of single- and multi-layered thin film structures with layer thicknesses in the nanometer range. XRR spectra are acquired by varying the incident angle in the grazing incidence regime while measuring the specular reflected X-ray beam. The shape of the resulting angle-dependent curve is correlated to changes of the electron density in the sample, but does not provide direct information on the presence or distribution of chemical elements in the sample. Grazing Incidence XRF (GIXRF) measures the X-ray fluorescence induced by an X-ray beam incident under grazing angles. The resulting angle dependent intensity curves are correlated to the depth distribution and mass density of the elements in the sample. GIXRF provides information on contaminations, total implanted dose and to some extent on the depth of the dopant distribution, but is ambiguous with regard to the exact distribution function. Both techniques use similar measurement procedures and data evaluation strategies, i.e. optimization of a sample model by fitting measured and calculated angle curves. Moreover, the applied sample models can be derived from the same physical properties, like atomic scattering/form factors and elemental concentrations; a simultaneous analysis is therefore a straightforward approach. This combined analysis in turn reduces the uncertainties of the individual techniques, allowing a determination of dose and depth profile of the implanted elements with drastically increased confidence level. Silicon wafers implanted with Arsenic at different implantation energies were measured by XRR and GIXRF using a combined, simultaneous measurement and data evaluation procedure. The data were processed using a self-developed software package (JGIXA), designed for simultaneous fitting of GIXRF and XRR data. The results were compared with depth profiles obtained by Secondary Ion Mass Spectrometry (SIMS).

Ingerle, D.; Meirer, F.; Pepponi, G.; Demenev, E.; Giubertoni, D.; Wobrauschek, P.; Streli, C.

2014-09-01

248

Micro energy dispersive X-ray fluorescence analysis of polychrome lead-glazed Portuguese faiences  

NASA Astrophysics Data System (ADS)

Several glazed ceramic pieces, originally produced in Coimbra (Portugal), were submitted to elemental analysis, having as premise the pigment manufacture production recognition. Although having been produced in Coimbra, their location changed as time passed due to historical reasons. A recent exhibition in Coimbra brought together a great number of these pieces and in situ micro Energy Dispersive X-ray Fluorescence (µ-EDXRF) analyses were performed in order to achieve some chemical and physical data on the manufacture of faiences in Coimbra. A non-commercial µ-EDXRF equipment for in situ analysis was employed in this work, carrying some important improvements when compared to the conventional ones, namely, analyzing spot sizes of about 100 µm diameter. The combination of a capillary X-ray lens with a new generation of low power microfocus X-ray tube and a drift chamber detector enabled a portable unit for micro-XRF with a few tens of µm lateral resolution. The advantages in using a portable system emphasized with polycapillary optics enabled to distinguish proximal different pigmented areas, as well as the glaze itself. These first scientific results on the pigment analysis of the collection of faiences seem to point to a unique production center with own techniques and raw materials. This conclusion arose with identification of the blue pigments having in its constitution Mn, Fe Co and As and the yellows as a result of the combination between Pb and Sb. A statistical treatment was used to reveal groups of similarities on the pigments elemental profile.

Guilherme, A.; Pessanha, S.; Carvalho, M. L.; dos Santos, J. M. F.; Coroado, J.

2010-04-01

249

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

1973-01-01

250

A maximum information utilization approach in X-ray fluorescence analysis  

NASA Astrophysics Data System (ADS)

X-ray fluorescence data bases have significant contradictions, and inconsistencies. We have identified that the main source of the contradictions, after the human factors, is rooted in the signal processing approaches. We have developed signal processors to overcome many of the problems by maximizing the information available to the analyst. These non-paralyzable, fully digital signal processors have yielded improved resolution, line shape, tailing and pile up recognition. The signal processors account for and register all events, sorting them into two spectra, one spectrum for the desirable or accepted events, and one spectrum for the rejected events. The information contained in the rejected spectrum is mandatory to have control over the measurement and to make a proper accounting and allocation of the events. It has established the basis for the application of the fundamental parameter method approach. A fundamental parameter program was also developed. The primary X-ray line shape (Lorentzian) is convoluted with a system line shape (Gaussian) and corrected for the sample material absorption, X-ray absorbers and detector efficiency. The peaks also can have, a lower and upper energy side tailing, including the physical interaction based long range functions. It also employs a peak and continuum pile up and can handle layered samples of up to five layers. The application of a fundamental parameter method demands the proper equipment characterization. We have also developed an inverse fundamental parameter method software package for equipment characterisation. The program calculates the excitation function at the sample position and the detector efficiency, supplying an internally consistent system.

Papp, T.; Maxwell, J. A.; Papp, A. T.

2009-08-01

251

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

252

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

253

Optimizing the operation of a high resolution vertical Johann spectrometer using a high energy fluorescer x-ray source  

SciTech Connect

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/{Delta}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 [National Security Technologies, LLC, 161 S. Vasco Rd., Suite A, Livermore, California 94550 (United States); Stewart, Richard [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States)

2010-10-15

254

Trace Element Mapping of a Biological Specimen by a Full-Field X-ray Fluorescence Imaging Microscope with a Wolter Mirror  

SciTech Connect

A full-field X-ray fluorescence imaging microscope with a Wolter mirror was applied to the element mapping of alfalfa seeds. The X-ray fluorescence microscope was built at the Photon Factory BL3C2 (KEK). X-ray fluorescence images of several growing stages of the alfalfa seeds were obtained. X-ray fluorescence energy spectra were measured with either a solid state detector or a CCD photon counting method. The element distributions of iron and zinc which were included in the seeds were obtained using a photon counting method.

Hoshino, Masato; Yamada, Norimitsu; Ishino, Toyoaki; Namiki, Takashi; Watanabe, Norio; Aoki, Sadao [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573 (Japan)

2007-01-19

255

Brain Iron Detected by SWI High Pass Filtered Phase Calibrated with Synchrotron X-Ray Fluorescence  

PubMed Central

Purpose To test the ability of susceptibility weighted images (SWI) and high pass filtered phase images to localize and quantify brain iron. Materials and Methods Magnetic resonance (MR) images of human cadaver brain hemispheres were collected using a gradient echo based SWI sequence at 1.5T. For X-ray fluorescence (XRF) mapping, each brain was cut to obtain slices that reasonably matched the MR images and iron was mapped at the iron K-edge at 50 or 100 ?m resolution. Iron was quantified using XRF calibration foils. Phase and iron XRF were averaged within anatomic regions of one slice, chosen for its range of iron concentrations and nearly perfect anatomic correspondence. X-ray absorption spectroscopy (XAS) was used to determine if the chemical form of iron was different in regions with poorer correspondence between iron and phase. Results Iron XRF maps, SWI, and high pass filtered phase data in nine brain slices from five subjects were visually very similar, particularly in high iron regions. The chemical form of iron could not explain poor matches. The correlation between the concentration of iron and phase in the cadaver brain was estimated as cFe [?g/g tissue] = 850?? + 110. Conclusion The phase shift ?? was found to vary linearly with iron concentration with the best correspondence found in regions with high iron content. PMID:20512886

Hopp, Karla; Popescu, Bogdan F.Gh.; McCrea, Richard P.E.; Harder, Sheri L.; Robinson, Christopher A.; Haacke, Mark E.; Rajput, Ali H.; Rajput, Alex; Nichol, Helen

2013-01-01

256

Americium characterization by X-ray fluorescence and absorption spectroscopy in plutonium uranium mixed oxide  

NASA Astrophysics Data System (ADS)

Plutonium uranium mixed oxide (MOX) fuels are currently used in nuclear reactors. The actinides in these fuels need to be analyzed after irradiation for assessing their behaviour with regard to their environment and the coolant. In this work the study of the atomic structure and next-neighbour environment of Am in the (Pu,U)O2 lattice in an irradiated (60 MW d kg-1) MOX sample was performed employing micro-X-ray fluorescence (µ-XRF) and micro-X-ray absorption fine structure (µ-XAFS) spectroscopy. The chemical bonds, valences and stoichiometry of Am (˜0.66 wt%) are determined from the experimental data gained for the irradiated fuel material examined in its peripheral zone (rim) of the fuel. In the irradiated sample Am builds up as Am3+ species within an [AmO8]13- coordination environment (e.g. >90%) and no (<10%) Am(IV) or (V) can be detected in the rim zone. The occurrence of americium dioxide is avoided by the redox buffering activity of the uranium dioxide matrix.

Degueldre, Claude; Cozzo, Cedric; Martin, Matthias; Grolimund, Daniel; Mieszczynski, Cyprian

2013-06-01

257

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

258

In vivo monitoring of toxic metals: assessment of neutron activation and x-ray fluorescence techniques  

SciTech Connect

To date, cadmium, lead, aluminum, and mercury have been measured in vivo in humans. The possibilities of monitoring other toxic metals have also been demonstrated, but no human studies have been performed. Neutron activation analysis appears to be most suitable for Cd and Al measurements, while x-ray fluorescence is ideally suited for measurement of lead in superficial bone. Filtered neutron beams and polarized x-ray sources are being developed which will improve in vivo detection limits. Even so, several of the current facilities are already suitable for use in epidemiological studies of selected populations with suspected long-term low-level ''environmental'' exposures. Evaluation and diagnosis of patients presenting with general clinical symptoms attributable to possible toxic metal exposure may be assisted by in vivo examination. Continued in vivo monitoring of industrial workers, especially follow-up measurements, will provide the first direct assessment of changes in body burden and a direct measure of the biological life-times of these metals in humans. 50 refs., 4 figs., 2 tabs.

Ellis, K.J.

1986-01-01

259

Investigation of X-ray fluorescence computed tomography (XFCT) and K-edge imaging.  

PubMed

This work provides a comprehensive Monte Carlo study of X-ray fluorescence computed tomography (XFCT) and K-edge imaging system, including the system design, the influence of various imaging components, the sensitivity and resolution under various conditions. We modified the widely used EGSnrc/DOSXYZnrc code to simulate XFCT images of two acrylic phantoms loaded with various concentrations of gold nanoparticles and Cisplatin for a number of XFCT geometries. In particular, reconstructed signal as a function of the width of the detector ring, its angular coverage and energy resolution were studied. We found that XFCT imaging sensitivity of the modeled systems consisting of a conventional X-ray tube and a full 2-cm-wide energy-resolving detector ring was 0.061% and 0.042% for gold nanoparticles and Cisplatin, respectively, for a dose of ? 10 cGy. Contrast-to-noise ratio (CNR) of XFCT images of the simulated acrylic phantoms was higher than that of transmission K-edge images for contrast concentrations below 0.4%. PMID:22692896

Bazalova, Magdalena; Kuang, Yu; Pratx, Guillem; Xing, Lei

2012-08-01

260

X-ray fluorescence spectrometry for Hayabusa and Hayabusa-2 missions  

NASA Astrophysics Data System (ADS)

We have successfully conducted X-ray fluorescence spectrometry of S-class asteroid 25143 Itokawa, using the charge-coupled device based X-ray spectrometer onboard Hayabusa after 2.5 years' cruise in interplanetary space. Radiation tolerance of CCD has been first examined under such conditions. Performance in FWHM of CCD outputs showed somewhat degradation after huge solar flares such as X11-class flare that happened in November 2003. However no substantial degradation was found during the rest of the cruise. But a gradual increase is found in number of bad pixels that show abnormal outputs time to time. Thus the onboard rejection of bad pixels called "Mask" function should better be installed. We have currently developed the "Mask" function technique using an FPGA for the onboard data handling logics, which will be used in the future missions such as Hayabusa-2. Hayabusa-2 is basically the re-made asteroid explorer of Hayabusa, but some minor changes must be done. The scientific instrument is not selected yet, surface elemental composition is a key information on sampling site selection before touchdown. The XRS could use to determine Mg/Si, Fe/Si, Ca/Si, Al/Si as well as S/Si. If much improved CCD system is used (basically difficult to make such major change), C/Si and O/Si are also determinable. These data sets are incredible for classification of C-class asteroid as the candidate asteroid of the target of Hayabusa-2 missions.

Okada, Tatsuaki; Yamamoto, Yukio; Ogawa, Kazunori; Arai, Takehiko; Shirai, Kei

261

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

262

Mercury dynamics in hair of rats exposed to methylmercury by synchrotron radiation X-ray fluorescence imaging  

SciTech Connect

Two dimensional distribution of mercury (Hg) in hair samples of rats exposed to methylmercury (MeHg) was analyzed by synchrotron radiation X-ray fluorescence (SR-XRF) imaging. Experiments with endogenous- and exogenous-model for MeHg exposure revealed that the metal level was obviously higher in the hair cortex after the former exposure whereas a dominant site that Hg distributed after the latter exposure was the cuticle. The method also provided us the Hg profile along the hair length with a single hair obtained by the endogenous model. Thus application of SR-XRF analysis to hair sample would facilitate biological monitoring to not only distinct Hg exposure but also determine its dynamics with only the specimen. 12 refs., 7 figs.

Shimojo, Nobuhiro; Homma-Takeda, Shino; Kumagai, Yoshito [Univ. of Tsukuba, Ibaraki (Japan)] [and others] [Univ. of Tsukuba, Ibaraki (Japan); and others

1997-05-02

263

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

PubMed

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

Koz, B

2014-09-01

264

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. PMID:23927295

Manohar, Nivedh; Reynoso, Francisco J.; Cho, Sang Hyun

2013-01-01

265

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

266

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

267

Simultaneous, coaxial neutron and x-ray imaging of inertial confinement fusion experiments at Omega  

NASA Astrophysics Data System (ADS)

The campaign to understand the dynamics of implosions in inertial confinement fusion experiments has generated a desire to compare neutron and x-ray images of the assembled targets. Several diagnostics currently exist, both at the Omega laser and the National Ignition Facility, which provide either neutron or x-ray radiography capabilities. However, these diagnostics view the target from different angles, and there is no verifiable co-registration of the images they produce. A system has therefore been developed to produce neutron and x-ray images simultaneously, through the same aperture and with the same view of the target. Recent experiments at the Omega laser have demonstrated this technique; the results are presented, and compared to images from other x-ray diagnostics, and to images generated with radiation-hydrodynamic simulations.

Danly, Christopher; Grim, Gary; Guler, Nevzat; Intrator, Miranda; Merrill, Frank; Volegov, Petr; Wilde, Carl

2012-10-01

268

Analysis of photographs and photo-paintings by energy-dispersive X-ray fluorescence spectroscopy  

NASA Astrophysics Data System (ADS)

A collection of Brazilian family photographs and photo-paintings from the beginning of the XX Century was analyzed by portable EDXRF (Energy-Dispersive X-Ray Fluorescence) spectroscopy. The spectrometer uses a Si-drift Amptek detector and an Oxford Cr-tube or an Oxford W-tube. For every region under analysis, spectra obtained with the W-tube were used to detect all the elements above Al, while the Cr-tube was used to obtain more accurate results for elements between Al and V. Thirty nine elements were identified in the photos, and the origin of the most important ones was discussed. These results can be used for cataloging, preservation and restoring procedures.

Neiva, Augusto Camara; Marcondes, Marli A.; Pinto, Herbert Prince Favero; Almeida, Paula Aline Durães

2014-02-01

269

Determination of thorium in geological materials by x-ray fluorescence spectrometry after anion exchange extraction  

SciTech Connect

The exchange capacity of the resin was determined to be 1 m equiv of Th/g dry resin. Synthetic calibration standards of thorium were prepared over a large concentration range, for use as an independent method of calibration. The advantages and disadvantages of direct x-ray fluorescence analysis are discussed. The lower limit of detection has been calculated according to Currie's convention and was found to be equal to 13 ..mu..g of Th/250 mg of resin, sufficient for the range of concentrations found in Th bearing minerals and ores. Results using Canadian syenite rocks and a suite of South African reference minerals show that the proposed method appears to be relatively precise and accurate for exploration geochemistry. 1 figure, 2 tables.

Roelandts, I.

1983-08-01

270

An elemental correlation study in cancerous breast tissue by total reflection x-ray fluorescence.  

PubMed

The total reflection x-ray fluorescence method (TRXRF) has been employed to determine of P, S, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Se, Rb, Sr, and Pb concentration in the benign breast tumor tissue from 68 women and in the cancerous breast tissue from 26 women. Concentrations of most of elements show enhancement in cancerous breast tissue. Examined elements compete for binding sites in the cell, change its enzymatic activity, and exert direct or indirect action on the carcinogenic process accelerating the growth of tumors. Inhibition of enzymatic activity caused by variation in trace element concentrations results in immunological breakdown of the body system. An attempt has been made to correlate measured trace element concentrations with the clinical stage of cancer. Physical bases of used analytical method, experimental setup, and the procedure of sample preparation are described. PMID:9404678

Majewska, U; Braziewicz, J; Bana?, D; Kubala-Kuku?, A; Gó?d?, S; Pajek, M; Smok, J; Urbaniak, A

1997-01-01

271

Possible use of pattern recognition for the analysis of Mars rover X-ray fluorescence spectra  

NASA Technical Reports Server (NTRS)

On the Mars rover sample-return mission, the rover vehicle will collect and select samples from different locations on the Martian surface to be brought back to earth for laboratory studies. It is anticipated that an in situ energy-dispersive X-ray fluorescence (XRF) spectrometer will be on board the rover. On such a mission, sample selection is of higher priority than in situ quantitative chemical anlaysis. With this in mind, a pattern recognition technique is proposed as a simple, direct, and speedy alternative to detailed chemical analysis of the XRF spectra. The validity and efficacy of the pattern recognition technique are demonstrated by the analyses of laboratory XRF spectra obtained from a series of geological samples, in the form both of standardized pressed pellets and as unprepared rocks. It is found that pattern recognition techniques applied to the raw XRF spectra can provide for the same discrimination among samples as a knowledge of their actual chemical composition.

Yin, Lo I; Trombka, Jacob I.; Seltzer, Stephen M.; Johnson, Robert G.; Philpotts, John A.

1989-01-01

272

X-ray spectra of Hercules X-1. 1: Iron line fluorescence from a subrelativistic shell  

NASA Technical Reports Server (NTRS)

The X-ray spectrum of Hercules X-1 was observed in the energy range 2-24 keV from August 29 to September 3, 1975. A broad iron line feature is observed in the normal high state spectrum. The line equivalent width is given along with its full-width-half-maximum energy. Iron line fluorescence from an opaque, cool shell of material at the Alfven surface provides the necessary luminosity in this feature. The line energy width can be due to Doppler broadening if the shell is forced to corotate with the pulsar at a radius 800 million cm. Implications of this model regarding physical conditions near Her X-1 are discussed.

Pravdo, S. H.; Becker, R. H.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; Swank, J. H.

1977-01-01

273

Determination of uranium in human urine by total reflection X-ray fluorescence  

NASA Astrophysics Data System (ADS)

Uranium has been classified as a toxic chemical. It affects the kidneys, with nephritis being the primarily chemically-induced effect in animals and humans. Intermediate-term studies on animals indicate that increased uranium doses are positively correlated with various biochemical effects and histopathological changes. Since the kidneys efficiently excrete in urine the major portion of solubilized uranium circulating in blood, an increased urinary uranium excretion can provide a sensitive quantitative measure of exposure, especially in the case of acute exposure. In the present work a method was developed for the quantitative determination of uranium in human urine. It combines the chemical treatment of urine, which results in a significant pre-concentration of uranium, with its subsequent detection by means of total reflection X-ray fluorescence (TXRF). The method has been proven to be relatively fast, offering detection limits that allow for monitoring uranium intake above normal levels.

Zarkadas, Ch; Karydas, A. G.; Paradellis, T.

2001-12-01

274

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

USGS Publications Warehouse

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

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

2005-01-01

275

Unique Properties of Thermally Tailored Copper: Magnetically Active Regions and Anomalous X-ray Fluorescence Emissions  

PubMed Central

When high-purity copper (?99.98%wt) is melted, held in its liquid state for a few hours with iterative thermal cycling, then allowed to resolidify, the ingot surface is found to have many small regions that are magnetically active. X-ray fluorescence analysis of these regions exhibit remarkably intense lines from “sensitized elements” (SE), including in part or fully the contiguous series V, Cr, Mn, Fe, and Co. The XRF emissions from SE are far more intense than expected from known impurity levels. Comparison with blanks and standards show that the thermal “tailoring” also introduces strongly enhanced SE emissions in samples taken from the interior of the copper ingots. For some magnetic regions, the location as well as the SE emissions, although persistent, vary irregularly with time. Also, for some regions extraordinarily intense “sensitized iron” (SFe) emissions occur, accompanied by drastic attenuation of Cu emissions. PMID:20037657

2009-01-01

276

Analytic Comparison between X-ray Fluorescence CT and K-edge CT  

E-print Network

X-ray fluorescence computed tomography (XFCT) and K-edge computed tomography (CT) are two important modalities to quantify a distribution of gold nanoparticles (GNPs) in a small animal for preclinical studies. It is valuable to determine which modality is more efficient for a given application. In this paper, we report a theoretical analysis in terms of signal-to-noise ratio (SNR) for the two modalities, showing that there is a threshold for the GNPs concentration and XFCT has a better SNR than K-edge CT if GNPs concentration is less than this threshold. Numerical simulations are performed and two kinds of phantoms are used to represent multiple concentration levels and feature sizes. Experimental results illustrate that XFCT is superior to K-edge CT when contrast concentration is lower than 0.4% which coincides with the theoretical analysis.

Feng, Peng; Cong, Wenxiang; Wei, Biao

2013-01-01

277

Analytic comparison between X-ray fluorescence CT and K-edge CT.  

PubMed

X-ray fluorescence computed tomography (XFCT) and K-edge computed tomography (CT) are two important modalities to quantify a distribution of gold nanoparticles (GNPs) in a small animal for preclinical studies. It is valuable to determine which modality is more efficient for a given application. In this paper, we report a theoretical analysis in terms of signal-to-noise ratio (SNR) for the two modalities, showing that there is a threshold of GNPs concentration such that XFCT has a better SNR than K-edge CT when GNPs concentration is less than this threshold, vice versa. Numerical tests are performed for XFCT and K-edge CT on two kinds of phantoms with multiple concentration levels and structural features. Experimental results illustrate that XFCT is superior to K-edge CT when contrast concentration is lower than 0.4% which coincides with the theoretical analysis. PMID:24557699

Feng, Peng; Cong, Wenxiang; Wei, Biao; Wang, Ge

2014-03-01

278

X-Ray Fluorescence to Determine Zn in Bolivian Children using Hair Samples  

NASA Astrophysics Data System (ADS)

As a first step in the evaluation of nutritional levels in Bolivian children (8-13 years-old), we carried out X-Ray Fluorescence measurements in hair samples of children belonging to different social classes and living either in rural areas or in cities. The aim of this study is to contribute to health policies tending to improve the global health of children and consequently avoid malnutrition. Our method intends to have maximum reliability and at the same time be as simple as possible from an experimental point of view. Additionally, we use this method to determine some other elements such as Fe, Cu, Pb, As and Hg, the latter three considered as contaminants that could be present in children living in areas which neighbor mines and industries. This work will be complemented by some biological and medical tests.

Tellería Narvaez, C. A.; Fernández Alcázar, S.; Barrientos Zamora, F. G.; Chungara Castro, J.; Luna Lauracia, I.; Mamani Tola, H.; Mita Peralta, E.; Muñoz Gosálvez, A. O.; Romero Bolaños, L. E.; Ramírez Ávila, G. M.

2014-06-01

279

Development of a combined portable x-ray fluorescence and Raman spectrometer for in situ analysis  

NASA Astrophysics Data System (ADS)

In this work, we have built a portable X-ray fluorescence (XRF) spectrometer in a planar configuration coupled to a Raman head and a digital optical microscope, for in situ analysis. Several geometries for the XRF apparatus and digital microscope are possible in order to overcome spatial constraints and provide better measurement conditions. With this combined spectrometer, we are now able to perform XRF and Raman measurements in the same point without the need for sample collection, which can be crucial when dealing with cultural heritage objects, as well as forensic analysis. We show the capabilities of the spectrometer by measuring several standard reference materials, as well as other samples usually encountered in cultural heritage, geological, as well as biomedical studies.

Guerra, M.; Longelin, S.; Pessanha, S.; Manso, M.; Carvalho, M. L.

2014-06-01

280

Validation of X-ray fluorescence-measured Swine femur lead against atomic absorption spectrometry.  

PubMed Central

The aim of this study was to apply the technique of (109)Cd-based K-shell X-ray fluorescence (XRF) bone lead measurements to swine femurs and to validate the concentrations obtained therefrom against an independent chemical measurement of bone lead: atomic absorption spectrometry (AAS). The femurs ranged in lead concentration from 1.0 to 24.5 microg of lead per gram of ashed bone, as measured by AAS. On average, XRF overestimated AAS-measured femur lead by 2.6 microg/g [95% confidence interval (CI), 1.1-4.0 microg/g], approximately 2 microg/g poorer than that observed in studies of human tibiae. Measurements of swine femur and, by extension, of nonhuman bones may require adjustment of the XRF spectrum peak extraction method. PMID:11712995

Todd, A C; Moshier, E L; Carroll, S; Casteel, S W

2001-01-01

281

Mapping metals in Parkinson's and normal brain using rapid-scanning x-ray fluorescence  

NASA Astrophysics Data System (ADS)

Rapid-scanning x-ray fluorescence (RS-XRF) is a synchrotron technology that maps multiple metals in tissues by employing unique hardware and software to increase scanning speed. RS-XRF was validated by mapping and quantifying iron, zinc and copper in brain slices from Parkinson's disease (PD) and unaffected subjects. Regions and structures in the brain were readily identified by their metal complement and each metal had a unique distribution. Many zinc-rich brain regions were low in iron and vice versa. The location and amount of iron in brain regions known to be affected in PD agreed with analyses using other methods. Sample preparation is simple and standard formalin-fixed autopsy slices are suitable. RS-XRF can simultaneously and non-destructively map and quantify multiple metals and holds great promise to reveal metal pathologies associated with PD and other neurodegenerative diseases as well as diseases of metal metabolism.

Popescu, Bogdan F. Gh; George, Martin J.; Bergmann, Uwe; Garachtchenko, Alex V.; Kelly, Michael E.; McCrea, Richard P. E.; Lüning, Katharina; Devon, Richard M.; George, Graham N.; Hanson, Akela D.; Harder, Sheri M.; Chapman, L. Dean; Pickering, Ingrid J.; Nichol, Helen

2009-02-01

282

X-ray fluorescence analysis of wear metals in used lubricating oils  

NASA Technical Reports Server (NTRS)

Used oils from several aircraft at NASA's Langley Research Center were analyzed over a three year period using X-ray fluorescence (XRF) and atomic emission spectrometry. The results of both analyses are presented and comparisons are made. Fe and Cu data for oil from four internal combustion engines are provided and XRF and atomic emission spectrometry measurements were found to be in perfect agreement. However, distributions were found in the case of oil from a jet aircraft engine whereby the latter method gave values for total iron concentration in the oil and did not distinguish between suspended particles and oil additives. XRF does not have these particle-size limitations; moreover, it is a faster process. It is concluded that XRF is the preferred method in the construction of a man-portable oil wear analysis instrument.

Maddox, W. E.; Kelliher, W. C.

1986-01-01

283

Determination of the implantation dose in silicon wafers by X-ray fluorescence analysis  

SciTech Connect

The ion dose implanted in silicon wafers was determined by X-ray fluorescence analysis after the implantation process. As only near-surface layers below 1-{mu}m thickness were considered, the calibration could be carried out with external standards consisting of thin films of doped gelatine spread on pure wafers. Dose values for Cr and Co were determined between 4 {times} 10{sup 15} and 2 {times} 10{sup 17} atoms/cm{sup 2}, the detection limits being about 3 {times} 10{sup 14} atoms/cm{sup 2}. The results are precise and accurate apart from a residual scatter of less than 7%. This was confirmed by flame atomic absorption spectrometry after volatilization of the silicon matrix as SiF{sub 4}. It was found that ion-current measurements carried out during the implantation process can have considerable systematic errors.

Klockenkaemper, R.; Becker, M.; Bubert, H.; Burba, P. (Institut fuer Spektrochemie und Angewandte Spektroskopie, Dortmund (West Germany)); Palmetshofer, L. (Johannes-Kepler-Universitaet, Linz (Austria))

1990-08-01

284

High resolution X-ray fluorescence imaging for a microbeam radiation therapy treatment planning system  

NASA Astrophysics Data System (ADS)

Microbeam radiation therapy (MRT) uses an array of high-dose, narrow (~100 ?m) beams separated by a fraction of a millimeter to treat various radio-resistant, deep-seated tumors. MRT has been shown to spare normal tissue up to 1000 Gy of entrance dose while still being highly tumoricidal. Current methods of tumor localization for our MRT treatments require MRI and X-ray imaging with subject motion and image registration that contribute to the measurement error. The purpose of this study is to develop a novel form of imaging to quickly and accurately assist in high resolution target positioning for MRT treatments using X-ray fluorescence (XRF). The key to this method is using the microbeam to both treat and image. High Z contrast media is injected into the phantom or blood pool of the subject prior to imaging. Using a collimated spectrum analyzer, the region of interest is scanned through the MRT beam and the fluorescence signal is recorded for each slice. The signal can be processed to show vascular differences in the tissue and isolate tumor regions. Using the radiation therapy source as the imaging source, repositioning and registration errors are eliminated. A phantom study showed that a spatial resolution of a fraction of microbeam width can be achieved by precision translation of the mouse stage. Preliminary results from an animal study showed accurate iodine profusion, confirmed by CT. The proposed image guidance method, using XRF to locate and ablate tumors, can be used as a fast and accurate MRT treatment planning system.

Chtcheprov, Pavel; Inscoe, Christina; Burk, Laurel; Ger, Rachel; Yuan, Hong; Lu, Jianping; Chang, Sha; Zhou, Otto

2014-03-01

285

A gas microstrip wide angle X-ray detector for application in synchrotron radiation experiments  

Microsoft Academic Search

The Gas Microstrip Detector has counting rate capabilities several orders of magnitude higher than conventional wire proportional counters while providing the same (or better) energy resolution for X-rays. In addition the geometric flexibility provided by the lithographic process combined with the self-supporting properties of the substrate offers many exciting possibilities for X-ray detectors, particularly for the demanding experiments carried out

J. E Bateman; J. F Connolly; G. E Derbyshire; D. M Duxbury; J. Lipp; J. A Mir; J. E Simmons; E. J Spill; R. Stephenson; B. R Dobson; R. C Farrow; W. I. Helsby; R. Mutikainen; I. Suni

2002-01-01

286

Precision spectroscopy of light kaonic atom X-rays in the SIDDHARTA experiment  

SciTech Connect

The SIDDHARTA experiment successfully measured kaonic atom X-rays using four gas targets of hydrogen, deuterium, helium-3, and helium-4 at the DA{Phi}NH electron-positron collider. Excellent performance of the SDDs under beam conditions was found in terms of X-ray energy resolution and a good background suppression capability. The preliminary results of the strong-interaction shifts of the kaonic atoms with Z = 1 and 2 are given.

Ishiwatari, T.; Cargnelli, M.; Marton, J.; Widmann, E.; Zmeskal, J. [Stefan-Meyer-Institut fuer subatomare Physik, Vienna (Austria); Bazzi, M.; Corradi, G.; Curceanu, C.; d'Uffizi, A.; Guaraldo, C.; Sandri, P. Levi; Lucherini, V.; Okada, S.; Pietreanu, D.; Rizzo, A.; Vidal, A. Romero; Scordo, A.; Doce, O. Vazquez [INFN, Laboratori Nazionali di Frascati, Frascati (Roma) (Italy); Beer, G. [Department of Physics and Astronomy, University of Victoria, Victoria B.C. (Canada); Bombelli, L. [Politechno di Milano, Sez. di Elettronica, Milano (Italy)

2010-12-28

287

X-ray absorption spectroscopy study of prototype chemical systems: Theory vs. experiment  

Microsoft Academic Search

Understanding the details of the intensities and spectral shapes of x-ray absorption spectra is a long-standing problem in chemistry and physics. Here, I present detailed studies of x-ray absorption for prototypical liquids, solids and gases with the goal of enhancing our general understanding of core-level spectroscopy via comparisons of modern theory and experiment. In Chapter 2, I investigate the importance

Craig Philip Schwartz

2010-01-01

288

High power laser pulse circulation experiment for compact quasi-monochromatic tunable X-ray source  

Microsoft Academic Search

Laser electron Compton scattering monochromatic tunable X-ray source using X-band (11.424GHz) electron linear accelerator and Q-switch Nd:YAG laser is under construction at Nuclear Professional School, the University of Tokyo. To enhance the X-ray intensity, we installed a laser circulation system. Now, we are performing the circulation experiment by using a high power laser (1.4J, 532nm). We confirmed the laser pulse

De Meng; Fumito Sakamoto; Tomohiko Yamamoto; Katsuhiro Dobashi; Mitsuru Uesaka; Hiroyuki Nose; Daisuke Ishida; Namio Kaneko; Yasuo Sakai

2007-01-01

289

X-Ray Preheating of Window Materials in Direct-Drive Shock-Wave Timing Experiments  

SciTech Connect

The optical properties of x-ray preheated planar-window materials relevant for shock-wave timing experiments were studied on the OMEGA Laser System. The behavior of diamond windows exposed to x rays is consistent with a simple model based on the generation of free charge carriers. Polystyrene windows showed indications of optical transitions due to molecular states that are created by the ionizing radiation.

Theobald, W.; Miller, J. E.; Boehly, T.R.; Vianello, E, Meyerhofer, D.D.; Sangster, T.C.; Eggert, J.; Celliers, P.M.

2007-01-24

290

X-ray fluorescence imaging reveals subcellular biometal disturbances in a childhood neurodegenerative disorder.  

PubMed

Biometals such as zinc, iron, copper and calcium play key roles in diverse physiological processes in the brain, but can be toxic in excess. A hallmark of neurodegeneration is a failure of homeostatic mechanisms controlling the concentration and distribution of these elements, resulting in overload, deficiency or mislocalization. A major roadblock to understanding the impact of altered biometal homeostasis in neurodegenerative disease is the lack of rapid, specific and sensitive techniques capable of providing quantitative subcellular information on biometal homeostasis in situ. Recent advances in X-ray fluorescence detectors have provided an opportunity to rapidly measure biometal content at subcellular resolution in cell populations using X-ray Fluorescence Microscopy (XFM). We applied this approach to investigate subcellular biometal homeostasis in a cerebellar cell line isolated from a natural mouse model of a childhood neurodegenerative disorder, the CLN6 form of neuronal ceroid lipofuscinosis, commonly known as Batten disease. Despite no global changes to whole cell concentrations of zinc or calcium, XFM revealed significant subcellular mislocalization of these important biological second messengers in cerebellar Cln6(nclf) (CbCln6(nclf) ) cells. XFM revealed that nuclear-to-cytoplasmic trafficking of zinc was severely perturbed in diseased cells and the subcellular distribution of calcium was drastically altered in CbCln6(nclf) cells. Subtle differences in the zinc K-edge X-ray Absorption Near Edge Structure (XANES) spectra of control and CbCln6(nclf) cells suggested that impaired zinc homeostasis may be associated with an altered ligand set in CbCln6(nclf) cells. Importantly, a zinc-complex, Zn(II)(atsm), restored the nuclear-to-cytoplasmic zinc ratios in CbCln6(nclf) cells via nuclear zinc delivery, and restored the relationship between subcellular zinc and calcium levels to that observed in healthy control cells. Zn(II)(atsm) treatment also resulted in a reduction in the number of calcium-rich puncta observed in CbCln6(nclf) cells. This study highlights the complementarities of bulk and single cell analysis of metal content for understanding disease states. We demonstrate the utility and broad applicability of XFM for subcellular analysis of perturbed biometal metabolism and mechanism of action studies for novel therapeutics to target neurodegeneration. PMID:24976945

Grubman, A; James, S A; James, J; Duncan, C; Volitakis, I; Hickey, J L; Crouch, P J; Donnelly, P S; Kanninen, K M; Liddell, J R; Cotman, S L; de Jonge; White, A R

2014-06-01

291

High energy resolution five-crystal spectrometer for high quality fluorescence and absorption measurements on an x-ray absorption spectroscopy beamline  

SciTech Connect

Fluorescence detection is classically achieved with a solid state detector (SSD) on x-ray absorption spectroscopy (XAS) beamlines. This kind of detection however presents some limitations related to the limited energy resolution and saturation. Crystal analyzer spectrometers (CAS) based on a Johann-type geometry have been developed to overcome these limitations. We have tested and installed such a system on the BM30B/CRG-FAME XAS beamline at the ESRF dedicated to the structural investigation of very dilute systems in environmental, material and biological sciences. The spectrometer has been designed to be a mobile device for easy integration in multi-purpose hard x-ray synchrotron beamlines or even with a laboratory x-ray source. The CAS allows to collect x-ray photons from a large solid angle with five spherically bent crystals. It will cover a large energy range allowing to probe fluorescence lines characteristic of all the elements from Ca (Z = 20) to U (Z = 92). It provides an energy resolution of 1-2 eV. XAS spectroscopy is the main application of this device even if other spectroscopic techniques (RIXS, XES, XRS, etc.) can be also achieved with it. The performances of the CAS are illustrated by two experiments that are difficult or impossible to perform with SSD and the complementarity of the CAS vs SSD detectors is discussed.

Llorens, Isabelle [CEA/DSM/INAC/SP2M/NRS, F-38054 Grenoble cedex 9 (France); Synchrotron SOLEIL - MARS beamline, L'Orme des Merisiers, F-91192 Gif sur Yvette (France); Lahera, Eric; Delnet, William; Proux, Olivier [Observatoire des Sciences de l'Univers de Grenoble, UMS 832 CNRS Universite Joseph Fourier, F-38041 Grenoble cedex 9 (France); BM30B/FAME beamline, ESRF, F-38043 Grenoble cedex 9 (France); Braillard, Aurelien; Hazemann, Jean-Louis; Prat, Alain; Testemale, Denis [BM30B/FAME beamline, ESRF, F-38043 Grenoble cedex 9 (France); Institut Neel, UPR 2940 CNRS, F-38042 Grenoble cedex 9 (France); Dermigny, Quentin; Gelebart, Frederic; Morand, Marc; Shukla, Abhay [Institut de Mineralogie et de Physique des Milieux Condenses, UMR 7590, 4 place Jussieu, F-75005 Paris (France); Bardou, Nathalie [Laboratoire de Photonique et de Nanostructures, UPR 20 CNRS, Route de Nozay, F-91460 Marcoussis (France); Ulrich, Olivier [CEA/DSM/INAC/SP2M/NRS, F-38054 Grenoble cedex 9 (France); BM32/IF beamline, ESRF, F-38043 Grenoble cedex 9 (France); Arnaud, Stephan; Berar, Jean-Francois; Boudet, Nathalie; Caillot, Bernard [Institut Neel, UPR 2940 CNRS, F-38042 Grenoble cedex 9 (France); BM02/D2AM beamline, ESRF, F-38043 Grenoble cedex 9 (France); Chaurand, Perrine; Rose, Jerome [Centre Europeen de Recherche et d'Enseignement des Geosciences de l'Environnement, UMR 7730, F-13545 Aix en Provence (France); and others

2012-06-15

292

Characterization of AlInN/AlN/GaN FET structures using x-ray diffraction, x-ray reflectometry and grazing incidence x-ray fluorescence analysis  

NASA Astrophysics Data System (ADS)

The structural parameters of AlInN/AlN/GaN high mobility field effect transistors (FETs) determine their electrical properties. The AlN-interlayer (spacer) thickness especially plays an important role to enhance the mobility and the density of the two dimensional electron gas (2DEG). However, structural characterization of this ultra-thin AlN-interlayer is ambiguous when only high resolution x-ray diffraction (HRXRD) and x-ray reflectometry (XRR) are taken into account. Here a combined layer analysis was performed using HRXRD, XRR and grazing incidence x-ray fluorescence (GIXRF) for the determination of the AlN-interlayer thickness. A sample series of AlInN/AlN/GaN FETs on Si(1?1?1) has been grown and analysed. The growth time of the AlN-interlayer was changed from 0 to 12 s and the AlInN barrier was grown nearly lattice matched to GaN with a nominal thickness of 5 nm. By the combination of HRXRD, XRR, GIXRF and simultaneous simulation of the data the determination of the spacer thickness was successfully performed.

Lesnik, Andreas; Bläsing, Jürgen; Hennig, Jonas; Dadgar, Armin; Krost, Alois

2014-09-01

293

X-ray fluorescence molecular imaging of high-Z tracers: investigation of a novel analyzer based setup  

NASA Astrophysics Data System (ADS)

A novel x-ray fluorescence imaging setup for the in vivo detection of high-Z tracer distributions is investigated for its application in molecular imaging. The setup uses an energy resolved detection method based on a Bragg reflecting analyzer array together with a multiple scatter reducing radial collimator. The aim of this work is to investigate the potential application of this imaging method to in vivo imaging in humans. A proof of principle experiment modeling a partial setup for the detection of gold nano-particles was conducted in order to test the feasibility of the proposed imaging method. Furthermore a Monte Carlo simulation of the complete setup was created in order to quantify the dependence of the image quality on the applied radiation dose and on the geometrical collimator parameters as well as on the analyzer crystal parameters. The Monte Carlo simulation quantifies the signal-to-noise ratio per radiation dose and its dependence on the collimator parameters. Thereby the parameters needed for a dose efficient in vivo imaging of gold nano-particle based tracer distributions are quantified. However also a number of problems are found like the fluorescence emission as well as scatter from the collimator material obscuring the tracer fluorescence and the potentially large scan time.

Müller, Bernhard H.; Hoeschen, Christoph; Grüner, Florian; Johnson, Thorsten R. C.

2014-03-01

294

Development of a Time-resolved Soft X-ray Spectrometer for Laser Produced Plasma Experiments  

SciTech Connect

A 2400 line/mm variable spaced grating spectrometer (VSG) has been used to measure soft x-ray emission (8-22 {angstrom}) from laser-produced plasma experiments at Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) Laser Facility. The spectrometer was coupled to a Kentech x-ray streak camera to study the temporal evolution of soft x-rays emitted from the back of mylar and copper foils irradiated at 10{sup 15} W/cm{sup 2}. The instrument demonstrated a resolving power of {approx} 120 at 19 {angstrom} with a time resolution of 31 ps. The time-resolved copper emission spectrum was consistent with a photodiode monitoring the laser temporal pulse shape and indicated that the soft x-ray emission follows the laser heating of the target. The time and spectral resolution of this diagnostic make it useful for studies of high temperature plasmas.

Cone, K V; Dunn, J; Schneider, M B; Baldis, H A; Brown, G V; Emig, J; James, D L; May, M J; Park, J; Shepherd, R; Widmann, K

2010-05-12

295

Development of an X-ray pixel detector with multi-port charge-coupled device for X-ray free-electron laser experiments  

SciTech Connect

This paper presents development of an X-ray pixel detector with a multi-port charge-coupled device (MPCCD) for X-ray Free-Electron laser experiments. The fabrication process of the CCD was selected based on the X-ray radiation hardness against the estimated annual dose of 1.6 × 10{sup 14} photon/mm{sup 2}. The sensor device was optimized by maximizing the full well capacity as high as 5 Me- within 50 ?m square pixels while keeping the single photon detection capability for X-ray photons higher than 6 keV and a readout speed of 60 frames/s. The system development also included a detector system for the MPCCD sensor. This paper summarizes the performance, calibration methods, and operation status.

Kameshima, Takashi [JASRI, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)] [JASRI, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Ono, Shun; Kudo, Togo; Ozaki, Kyosuke; Kirihara, Yoichi; Kobayashi, Kazuo; Inubushi, Yuichi [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)] [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Yabashi, Makina; Hatsui, Takaki, E-mail: hatsui@spring8.or.jp [JASRI, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan) [JASRI, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Horigome, Toshio [Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan)] [Institute for Molecular Science, Myodaiji, Okazaki 444-8585 (Japan); Holland, Andrew; Holland, Karen [XCam, Ltd, 2 Stone Circle Road, Round Spinney Industrial Estate, Northampton NN3 8RF (United Kingdom)] [XCam, Ltd, 2 Stone Circle Road, Round Spinney Industrial Estate, Northampton NN3 8RF (United Kingdom); Burt, David [e2v, 106 Waterhouse Lane, Chelmsford, Essex CM1 2QU (United Kingdom)] [e2v, 106 Waterhouse Lane, Chelmsford, Essex CM1 2QU (United Kingdom); Murao, Hajime [Meisei Electric Co. Ltd, Naganuma 2223, Isesaki, Gunma 372-8585 (Japan)] [Meisei Electric Co. Ltd, Naganuma 2223, Isesaki, Gunma 372-8585 (Japan)

2014-03-15

296

Influence of the water content on X-ray fluorescence core-scanning measurements in soft marine sediments  

Microsoft Academic Search

The X-ray fluorescence (XRF) core scanner provides bulk-sediment chemistry data measured nondestructively at the split core sediment surface. Although this method is widely accepted, there is little known about the effects of physical properties such as density and water content on XRF core scanner data. Comparison of XRF scanner measurements from the sediment surface and dry powder samples of sediment

Rik Tjallingii; Ursula Röhl; Martin Kölling; Torsten Bickert

2007-01-01

297

The use of X-ray fluorescence spectrometry for the analysis of plants, especially lichens, employed in biological monitoring  

Microsoft Academic Search

Several analytical techniques are available for the elemental analysis of plants such as lichens used in pollution monitoring studies. This paper examines the advantages and disadvantages of one technique, X-ray fluorescence spectrometry, for determining the elemental content of lichen. The technique can be used for macro nutrients such as K and Ca and for trace metals such as Cu, Pb

D. H. S. Richardson; M. Shore; R. Hartree; R. M. Richardson

1995-01-01

298

Analysis of low Z elements in various environmental samples with total reflection X-ray fluorescence (TXRF) spectrometry  

Microsoft Academic Search

Recently there is a growing interest in low Z elements such as carbon, oxygen up to sulphur and phosphorus in biological specimen. Total reflection X-ray fluorescence (TXRF) spectrometry is a suitable technique demanding only very small amounts of sample. On the other side, the detection of low Z elements is a critical point of this analytical technique. Besides other effects,

H. Hoefler; C. Streli; P. Wobrauschek; M. Óvári; Gy. Záray

2006-01-01

299

Synchrotron X-ray fluorescence studies of a bromine-labelled cyclic RGD peptide interacting with individual tumor cells  

PubMed Central

The first example of synchrotron X-ray fluorescence imaging of cultured mammalian cells in cyclic peptide research is reported. The study reports the first quantitative analysis of the incorporation of a bromine-labelled cyclic RGD peptide and its effects on the biodistribution of endogenous elements (for example, K and Cl) within individual tumor cells. PMID:23412478

Sheridan, Erin J.; Austin, Christopher J. D.; Aitken, Jade B.; Vogt, Stefan; Jolliffe, Katrina A.; Harris, Hugh H.; Rendina, Louis M.

2013-01-01

300

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

EPA Science Inventory

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

301

Soil Heavy Metal Pollution along Subin River in Kumasi, Ghana; Using X-Ray Fluorescence (XRF) Analysis  

Microsoft Academic Search

This study is aimed to analyze and assess the existence of heavy metal pollution in the surface soils along Subin River in the Kumasi metropolis using X-Ray Fluorescence (XRF) analysis. Twenty (20) soil samples were collected along the River at regular interval of 5 m (covering entire area of about 100 m2), with the aid of a core sampler. The

K. Kodom; J. Wiafe-Akenten; D. Boamah

2010-01-01

302

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

EPA Science Inventory

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

303

FIELD MEASUREMENT TECHNOLOGY FOR MERCURY IN SOIL AND SEDIMENT NITON'S XLI/XLT 700 SERIES X-RAY FLUORESCENCE ANALYZER  

EPA Science Inventory

NITON's XL-700 Series X-ray fluorescence analyzers were demonstrated under the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation Program in May 2003 at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The purpose of the Demonstration...

304

Scanning micro-X-ray fluorescence elemental mapping: A new tool for the study of laminated sediment records  

Microsoft Academic Search

The utility of elemental mapping by scanning X-ray fluorescence (XRF) in the study of annual laminated sedimentary records was investigated on eight annually laminated sediment types. The examples were chosen to illustrate the potential of this approach in environments dominated by terrigenous, biological and chemical deposition. Individual laminae were identifiable in elemental maps of all sediment types and were enhanced

T. M. Shanahan; J. T. Overpeck; J. B. Hubeny; J. King; F. S. Hu; K. Hughen; G. Miller; J. Black

2008-01-01

305

EVALUATION OF PORTABLE X-RAY FLUORESCENCE SPECTROMETER FOR MEASUREMENT OF LEAD IN PAINT, SOIL AND DUST  

EPA Science Inventory

Three widely used commercially available portable X-ray fluorescence spectrometers were evaluated for precision and accuracy of measurement of lead in paint. ncluded were two direct reading instruments and one spectrum analyzer. est materials were prepared by spiking oil-based an...

306

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - FIELD PORTABLE X-RAY FLUORESCENCE ANALYZER - METOREX, INC. X-MET 920-P AND 940  

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 (1) to determine how well FPXRF analyzers perform in comparison to standard reference...

307

Analysis of pigments and inks on oil paintings and historical manuscripts using total reflection x?ray fluorescence spectrometry  

Microsoft Academic Search

Old oil paintings and illuminated historical manuscripts are valuable objects of cultural heritage. Pigments and inks once used for these artefacts today allow insights of art historical or archaeological relevance. For their identification, a number of non-destructive spectroanalytical methods can be applied. This paper first gives a historical review and describes fundamentals of optical and x-ray fluorescence spectrometry including instrumentation

R. Klockenkämper; A. von Bohlen; L. Moens

2000-01-01

308

[Determination of phosphorus and iron in cocatalyst for maximum propylene production by X-ray fluorescence spectrometry].  

PubMed

The aim of the authors' research work was to develop a new technique for quantitative analysis of phosphorus and iron contents in cocatalyst by X-ray fluorescence spectrometry (XRFS). A set of standard samples synthesized were prepared for the experiments with this purpose when the interferences of inter-elements had been corrected by empirical coefficient method. The standard samples were manually synthesized, and the powder pellets were used for sample preparation and the matrix effects were corrected by the experience coefficients. The characteristic X-rays of phosphorus and iron elements could selectively be determined with the enhanced accuracy and reduced time consumption within a range without signal interference from main-component elements. Manufacturing sample and measurement conditions of the new method was brought up; the matrix effects of cocatalyst samples were verified by empirical coefficient method. The results of experiment show that the accuracy and precision of this method satisfactorily had the high repeatability. The measuring ranges of elements were omega 0.01%-2.5% for phosphorus and omega 0.01%-2.5% for iron with the relative deviations of 0.34% for phosphorus and 0.59% for iron, respectively. This method showed satisfied accordant results compared with the chemical method and inductively coupled plasma (ICP). It has provided the analytical values for phosphorus and iron in cocatalyst for maximum propylene production. This new method has the advantages of satisfactory accuracy, high precision, less interference, easy sample handling and efficiency. In addition, the samples are not decomposed during the analysis process when each sample only requires 5 minutes for measurement This new method will be able to meet the growing demands of quantitative analysis of phosphorus and iron content in cocatalysts. This method had the satisfactory accuracy and precision, the analytical range was large, and had been successfully applied to the determination of phosphorus and iron in cocatalyst. PMID:19798992

Yang, Yi-Qing; Chen, Hui; Wang, Ya-Hong; Lü-Hong; Pan, Zhi-Shuang

2009-07-01

309

Development of Standard Samples for on-board Calibration of a New Planetary X-Ray Fluorescence Spectrometer  

NASA Astrophysics Data System (ADS)

At the Planetary Sciences and Remote Sensing research group at Freie Universität Berlin an SCD-based X-Ray Fluorescence Spectrometer is being developed to be employed on planetary orbiters to conduct direct, passive energy-dispersive x-ray fluorescence measurements of planetary surfaces through measuring the emitted X-Ray fluorescence induced by solar x-rays and high energy particles. Because the Sun is a highly variable radiation source, the intensity of solar X-Ray radiation has to be monitored constantly to allow for comparison and signal calibration of X-Ray radiation from lunar surface materials. Measurements are obtained by indirectly monitoring incident solar x-rays emitted from a calibration sample. This has the additional advantage of minimizing the risk of detector overload and damage during extreme solar events such as high-energy solar flares and particle storms as only the sample targets receive the higher radiation load directly (while the monitor is never directly pointing towards the Sun). Quantitative data are being obtained and can be subsequently analysed through synchronous measurement of fluorescence of the Moon's surface by the XRF-S main instrument and the emitted x-ray fluorescence of calibration samples by the XRF-S-ISM (Indirect Solar Monitor). We are currently developing requirements for 3 sample tiles for onboard correction and calibration of XRF-S, each with an area of 3-9 cm2 and a maximum weight of 45 g. This includes development of design concepts, determination of techniques for sample manufacturing, manufacturing and testing of prototypes and statistical analysis of measurement characteristics and quantification of error sources for the advanced prototypes and final samples. Apart from using natural rock samples as calibration sample, we are currently investigating techniques for sample manufacturing including laser sintering of rock-glass on metals, SiO2-stabilized mineral-powders, or artificial volcanic glass. High precision measurements of the chemical composition of the final samples (EPMA, various energy-dispersive XRF) will serve as calibration standard for XRF-S. Development is funded by the German Aerospace Agency under grant 50 JR 1303.

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

2014-05-01

310

Ultraviolet Germicidal Irradiation and Its Effects on Elemental Distributions in Mouse Embryonic Fibroblast Cells in X-Ray Fluorescence Microanalysis  

PubMed Central

Rapidly-frozen hydrated (cryopreserved) specimens combined with cryo-scanning x-ray fluorescence microscopy provide an ideal approach for investigating elemental distributions in biological cells and tissues. However, because cryopreservation does not deactivate potentially infectious agents associated with Risk Group 2 biological materials, one must be concerned with contamination of expensive and complicated cryogenic x-ray microscopes when working with such materials. We employed ultraviolet germicidal irradiation to decontaminate previously cryopreserved cells under liquid nitrogen, and then investigated its effects on elemental distributions under both frozen hydrated and freeze dried states with x-ray fluorescence microscopy. We show that the contents and distributions of most biologically important elements remain nearly unchanged when compared with non-ultraviolet-irradiated counterparts, even after multiple cycles of ultraviolet germicidal irradiation and cryogenic x-ray imaging. This provides a potential pathway for rendering Risk Group 2 biological materials safe for handling in multiuser cryogenic x-ray microscopes without affecting the fidelity of the results. PMID:25706293

Jin, Qiaoling; Vogt, Stefan; Lai, Barry; Chen, Si; Finney, Lydia; Gleber, Sophie-Charlotte; Ward, Jesse; Deng, Junjing; Mak, Rachel; Moonier, Nena; Jacobsen, Chris

2015-01-01

311

Fast-scanning high-flux microprobe for biological X-ray fluorescence microscopy and microXAS  

SciTech Connect

There is a growing interest in the biomedical community in obtaining information concerning the distribution and local chemical environment of metals in tissues and cells. Recently, biological X-ray fluorescence microscopy (XFM) has emerged as the tool of choice to address these questions. A fast-scanning high-flux X-ray microprobe, built around a recently commissioned pair of 200 mm-long Rh-coated silicon Kirkpatrick-Baez mirrors, has been constructed at BioCAT beamline 18ID at the Advanced Photon Source. The new optical system delivers a flux of 1.3 x 10{sup 12} photons s{sup -1} into a minimum focal spot size of {approx}3-5 {micro}m FWHM. A set of Si drift detectors and bent Laue crystal analyzers may be used in combination with standard ionization chambers for X-ray fluorescence measurements. BioCAT's scanning software allows fast continuous scans to be performed while acquiring and storing full multichannel analyzer spectra per pixel on-the-fly with minimal overhead time (<20 ms per pixel). Together, the high-flux X-ray microbeam and the rapid-scanning capabilities of the BioCAT beamline allow the collection of XFM and micro X-ray absorption spectroscopy (microXAS) measurements from as many as 48 tissue sections per day. This paper reports the commissioning results of the new instrument with representative XFM and microXAS results from tissue samples.

Barrea, R.A.; Gore, D.; Kujala, N.; Karanfil, C.; Kozyrenko, S.; Heurich, R.; Vukonich, M.; Huang, R.; Paunesku, T.; Woloschak, G.; Irving, T.C. (IIT); (NWU); (HWMRI)

2010-07-23

312

Ultraviolet germicidal irradiation and its effects on elemental distributions in mouse embryonic fibroblast cells in x-ray fluorescence microanalysis.  

PubMed

Rapidly-frozen hydrated (cryopreserved) specimens combined with cryo-scanning x-ray fluorescence microscopy provide an ideal approach for investigating elemental distributions in biological cells and tissues. However, because cryopreservation does not deactivate potentially infectious agents associated with Risk Group 2 biological materials, one must be concerned with contamination of expensive and complicated cryogenic x-ray microscopes when working with such materials. We employed ultraviolet germicidal irradiation to decontaminate previously cryopreserved cells under liquid nitrogen, and then investigated its effects on elemental distributions under both frozen hydrated and freeze dried states with x-ray fluorescence microscopy. We show that the contents and distributions of most biologically important elements remain nearly unchanged when compared with non-ultraviolet-irradiated counterparts, even after multiple cycles of ultraviolet germicidal irradiation and cryogenic x-ray imaging. This provides a potential pathway for rendering Risk Group 2 biological materials safe for handling in multiuser cryogenic x-ray microscopes without affecting the fidelity of the results. PMID:25706293

Jin, Qiaoling; Vogt, Stefan; Lai, Barry; Chen, Si; Finney, Lydia; Gleber, Sophie-Charlotte; Ward, Jesse; Deng, Junjing; Mak, Rachel; Moonier, Nena; Jacobsen, Chris

2015-01-01

313

Improved micro x-ray fluorescence spectrometer for light element analysis  

SciTech Connect

Since most available micro x-ray fluorescence (micro-XRF) spectrometers operate in air, which does not allow the analysis of low-Z elements (Z{<=}14), a special micro-XRF spectrometer has been designed to extend the analytical range down to light elements (Z{>=}6). It offers improved excitation and detection conditions necessary for light element analysis. To eliminate absorption of the exciting and fluorescent radiation, the system operates under vacuum condition. Sample mapping is automated and controlled by specialized computer software developed for this spectrometer. Several different samples were measured to test and characterize the spectrometer. The spot size has been determined by scans across a 10 {mu}m Cu wire which resulted in a full width at half maximum of 31 {mu}m for Mo K{alpha} line (17.44 keV) and 44 {mu}m effective beam size for the Cu K edge and 71 {mu}m effective beam size for the Cu L edge. Lower limits of detection in the picogram range for each spot (or {mu}g/cm{sup 2}) were obtained by measuring various thin metal foils under different conditions. Furthermore, detection limits in the parts per million range were found measuring NIST621 standard reference material. Area scans of a microscopic laser print and NaF droplet were performed to show mapping capabilities.

Smolek, Stephan; Streli, Christina; Zoeger, Norbert; Wobrauschek, Peter [Atominstitut, Vienna University of Technology, Stadionallee 2, 1020 Vienna (Austria)

2010-05-15

314

Novel handheld x-ray fluorescence spectrometer for routine testing for the presence of lead  

NASA Astrophysics Data System (ADS)

RMD is developing a safe, inexpensive, and easy to operate lead detector for retailers and consumers that can reliably detect dangerous levels of lead in toys and other household products. Lead and its compounds have been rated as top chemicals that pose a great threat to human health. However, widespread testing for environmental lead is rarely undertaken until lead poisoning has already been diagnosed. The problem is not due to the accuracy or sensitivity of existing lead detection technology, but rather to the high expense, safety and licensing barriers of available test equipment. An inexpensive and easy to use lead detector would enable the identification of highly contaminated objects and areas and allow for timely and cost effective remediation. The military has similar needs for testing for lead and other heavy elements such as mercury, primarily in the decontamination of former military properties prior to their return to civilian use. RMD's research and development efforts are abased on advanced solid-state detectors combined with recently patented lead detection techniques to develop a consumer oriented lead detector that will be widely available and easy and inexpensive to use. These efforts will result in an instrument that offers: (1) high sensitivity, to identify objects containing dangerous amounts of lead, (2) low cost to encourage widespread testing by consumers and other end users and (3) convenient operation requiring no training or licensing. In contrast, current handheld x-ray fluorescence spectrometers either use a radioactive source requiring licensing and operating training, or use an electronic x-ray source that limits their sensitivity to surface lead.

Rensing, Noa M.; Tiernan, Timothy C.; Squillante, Michael R.

2011-06-01

315

X-ray Fluorescence Observations of the Moon by SMART-1/D-CIXS  

NASA Astrophysics Data System (ADS)

Introduction The SMART-1 mission to the Moon included in its payload D-CIXS, a compact X-ray spectrometer [1], [2] SMART-1 was a technology evaluation mission, and D-CIXS was the first of a new generation of planetary X-ray spectrometers. Novel technologies enabled new capabilities for measuring the fluorescent yield of a planetary surface or atmosphere which is illuminated by solar X-rays. During the extended SMART-1 cruise phase, observations of the Earth showed strong argon emission, providing a good source for calibration and demonstrating the potential of the technique. At the Moon, observations showed a first unambiguous remote sensing of calcium in the lunar regolith (Grande et al 2007) (Fig 1). Data obtained were broadly consistent with current understanding of mare and highland composition. Ground truth was provided by the returned Apollo and Luna sample sets. We have extended our observations to comparisons of Lunar near and farside, and by careful analysis enabled new elemental lines to be observed. Observations: In March, 2005, the SMART-1 spacecraft reached its nominal lunar orbit, and we began full commissioning for lunar operations. During the pre-commissioning period in mid-January, 2005, observations of the lunar surface were made which coincided with the occurrence of several major M and X class flares. This opportunity provided an excellent chance to observe spatially localized fluorescence from the lunar surface. X-ray fluorescent elemental lines from the lunar surface are detected by all three facets of D-CIXS while the XSM instrument observes the input solar spectrum. At the end of this interval, a long duration M-class solar flare began at 06:00 UTC on the 15th of January, 2005. The flare lasted for more than 1 hour but only ~30 minutes corresponded to D-CIXS observations. At this time SMART-1 was orbiting over the Moon's near-side eastern limb from about the equator, traveling northwards. As SMART-1 flew north, its altitude was also increasing from around 2100 km at 06:00 to ~3100 km at 06:35. Due to the nature of SMART-1's orbit and thermal dynamics, the spacecraft was performing a mid-orbit slew (rotation), and so D-CIXS's three facets had different surface ground tracks during the observation of interest. However, this variability in footprints was very fortuitous as the instrument FOVs included areas of both mare basalt and highland lithologies, which have different and recognizable elemental signatures. Facet 1 (thin Al-filter, 12º FOV) was oriented throughout the observation toward highland areas to the northeast of Mare Crisium. Facet 3 (Mg-filter, 12º FOV) had a ground track that crossed Mare Crisium. Due to the 12º FOV and the 2100 km altitude, the facet 3 footprint always contains a mixture of mare and highland regions. The footprint of facet 2 (thin Alfilter, 8º FOV) encompassed the regions between the two facets shown and covered a mixture of mare and highland regions but with a smaller signal due to its narrower FOV. Fig. 1 shows the particle background corrected spectra from summed data of the 3 D-CIXS facets for the interval 06:00 UTC to 06:35 UTC. Separate facet spectra have been derived by co-adding data from detectors. Essentially, elemental lines seen in the three different facet spectra represent an averaged geochemical signature from the areas covered by the D-CIXS ground tracks. The spectra shown in figure 5 indicate that lowenergy lines (Mg: 1.25 keV, Al; 1.49 keV and Si: 1.74 keV) are observed in detectors from Facet 1 and 2 (Alfilter). Detectors in Facet 3 are covered by a Magnesium filter which was designed to attenuate the signal from Al and Si X-rays, and so in the Facet 3 spectrum Mg is the only significant low-energy peak detected. Data taken from the Facet 3 spectrum also show a clear Fe peak at around 6.4 keV which is interpreted to be related to fluorescence from Mare Crisium (see below). All three facets clearly show the detection of a Ca emission peak at ~3.69 keV. Although inferences about the distribution of Ca in the lunar crust have been made indirectly f

Grande, Manuel; Swinyard, B.; Joy, K. H.; Kellett, Barry J.; Crawford, Ian A.; Howe, Chris J.

2008-09-01

316

Fast automatic segmentation of anatomical structures in x-ray computed tomography images to improve fluorescence molecular tomography reconstruction  

NASA Astrophysics Data System (ADS)

The recent development of hybrid imaging scanners that integrate fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) allows the utilization of x-ray information as image priors for improving optical tomography reconstruction. To fully capitalize on this capacity, we consider a framework for the automatic and fast detection of different anatomic structures in murine XCT images. To accurately differentiate between different structures such as bone, lung, and heart, a combination of image processing steps including thresholding, seed growing, and signal detection are found to offer optimal segmentation performance. The algorithm and its utilization in an inverse FMT scheme that uses priors is demonstrated on mouse images.

Freyer, Marcus; Ale, Angelique; Schulz, Ralf B.; Zientkowska, Marta; Ntziachristos, Vasilis; Englmeier, Karl-Hans

2010-05-01

317

Synchrotron x-ray fluorescence microprobe: Quantification and mapping of mixed valence state samples using micro-XANES  

SciTech Connect

The synchrotron x-ray fluorescence microprobe is a valuable instrument for quantification and mapping of mixed valence state samples with high spatial resolution and elemental sensitivity. A method has been developed for quantifying the proportions of Fe[sup 2+] and Fe[sup 3+] with 100 [mu]m spatial resolution and better than 100 ppm sensitivity using x-ray absorption near-edge structure (XANES). Applications of valence state mapping have been made to selenium in water-saturated sediments and manganese associated with wheat roots attacked by the take-all fungus.

Sutton, S.R. (Department of the Geophysical Sciences and Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637 (United States)); Bajt, S. (Department of the Geophysical Sciences and Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637 (United States) Department of Applied Science, Brookhaven National Laboratory, Upton, New York 11973 (United States)); Delaney, J. (Department of Geological Sciences, Rutgers University, New Brunswick, New Jersey 08903 (United States)); Schulze, D. (Agronomy Department, Purdue University, W. Lafayette, Indiana 47907 (United States)); Tokunaga, T. (Earth Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States))

1995-02-01

318

Photospheric Fluorescence and Resonance Scattering: Non Classical Diagnostics and the Future of X-ray Stellar Spectroscopy  

NASA Technical Reports Server (NTRS)

High resolution AXAF and XMM observations of stellar coronae will yield a wealth of X-ray plasma line diagnostics that will provide a giant leap forward in our understanding of coronal densities, abundance anomalies and emission measure distributions. Unfortunately, there is one very basic unanswered question in the physics of active stellar coronae that the usual plasma diagnostics cannot address directly: What are the spatial characteristics of stellar coronae-the scale height and filling factor? What do other stellar coronae actually look like? I will discuss two novel diagnostics of coronal geometry and their application to future X-ray spectra: photospheric fluorescence and resonance line optical depths.

Drake, Jeremy

1998-01-01

319

Gemas: issues from the comparison of aqua regia and X-ray fluorescence results  

NASA Astrophysics Data System (ADS)

The comparison of analytical results from aqua regia (AR) and X-ray fluorescence spectroscopy (XRF) can provide information on soil processes controlling the element distribution. The GEMAS (GEochemical Mapping of Agricultural and grazing land Soils) agricultural soil database is used for this comparison. Analyses for the same suite of elements and parameters were carried out in the same laboratory under strict quality control procedures. Sample preparation has been conducted at the laboratory of the The comparison of analytical results from aqua regia (AR) and X-ray fluorescence spectroscopy (XRF) can provide information on soil processes controlling the element distribution in soil. The GEMAS (GEochemical Mapping of Agricultural and grazing land Soils) agricultural soil database, consisting of 2 x ca. 2100 samples spread evenly over 33 European countries, is used for this comparison. Analyses for the same suite of elements and parameters were carried out in the same laboratory under strict quality control procedures. Sample preparation has been conducted at the laboratory of the Geological Survey of the Slovak Republic, AR analyses were carried out at ACME Labs, and XRF analyses at the Federal Institute for Geosciences and Natural Resources, Germany Element recovery by AR is very different, ranging from <1% (e.g. Na, Zr) to > 80% (e.g. Mn, P, Co). Recovery is controlled by mineralogy of the parent material, but geographic and climatic factors and the weathering history of the soils are also important. Nonetheless, even the very low recovery elements show wide ranges of variation and spatial patterns that are affected by other factors than soil parent material. For many elements soil pH have a clear influence on AR extractability: under acidic soil conditions almost all elements tend to be leached and their extractability is generally low. It progressively increases with increasing pH and is highest in the pH range 7-8. Critical is the clay content of the soil that almost for all elements correspond to higher extractability with increasing clay abundance. Also other factors such as organic matter content of soil, Fe and Mn occurrence are important for certain elements or in selected areas. This work illustrates that there are significant differences in the extractability of elements from soils and addresses important influencing factors related to soil properties, geology, climate.

Dinelli, Enrico; Birke, Manfred; Reimann, Clemens; Demetriades, Alecos; DeVivo, Benedetto; Flight, Dee; Ladenberger, Anna; Albanese, Stefano; Cicchella, Domenico; Lima, Annamaria

2014-05-01

320

X-ray diagnostics for the Levitated Dipole Experiment  

E-print Network

Initial plasma experiments in the Levitated Dipole Experiment focus on producing hot electron, high beta plasmas using a supported dipole configuration. Plasmas are created using multifrequency ECRH and it is therefore ...

Ellsworth, Jennifer L

2004-01-01

321

Monte Carlo simulation of X-ray imaging and spectroscopy experiments using quadric geometry and variance reduction techniques  

NASA Astrophysics Data System (ADS)

The simulation of X-ray imaging experiments is often performed using deterministic codes, which can be relatively fast and easy to use. However, such codes are generally not suitable for the simulation of even slightly more complex experimental conditions, involving, for instance, first-order or higher-order scattering, X-ray fluorescence emissions, or more complex geometries, particularly for experiments that combine spatial resolution with spectral information. In such cases, simulations are often performed using codes based on the Monte Carlo method. In a simple Monte Carlo approach, the interaction position of an X-ray photon and the state of the photon after an interaction are obtained simply according to the theoretical probability distributions. This approach may be quite inefficient because the final channels of interest may include only a limited region of space or photons produced by a rare interaction, e.g., fluorescent emission from elements with very low concentrations. In the field of X-ray fluorescence spectroscopy, this problem has been solved by combining the Monte Carlo method with variance reduction techniques, which can reduce the computation time by several orders of magnitude. In this work, we present a C++ code for the general simulation of X-ray imaging and spectroscopy experiments, based on the application of the Monte Carlo method in combination with variance reduction techniques, with a description of sample geometry based on quadric surfaces. We describe the benefits of the object-oriented approach in terms of code maintenance, the flexibility of the program for the simulation of different experimental conditions and the possibility of easily adding new modules. Sample applications in the fields of X-ray imaging and X-ray spectroscopy are discussed. Catalogue identifier: AERO_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AERO_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 83617 No. of bytes in distributed program, including test data, etc.: 1038160 Distribution format: tar.gz Programming language: C++. Computer: Tested on several PCs and on Mac. Operating system: Linux, Mac OS X, Windows (native and cygwin). RAM: It is dependent on the input data but usually between 1 and 10 MB. Classification: 2.5, 21.1. External routines: XrayLib (https://github.com/tschoonj/xraylib/wiki) Nature of problem: Simulation of a wide range of X-ray imaging and spectroscopy experiments using different types of sources and detectors. Solution method: XRMC is a versatile program that is useful for the simulation of a wide range of X-ray imaging and spectroscopy experiments. It enables the simulation of monochromatic and polychromatic X-ray sources, with unpolarised or partially/completely polarised radiation. Single-element detectors as well as two-dimensional pixel detectors can be used in the simulations, with several acquisition options. In the current version of the program, the sample is modelled by combining convex three-dimensional objects demarcated by quadric surfaces, such as planes, ellipsoids and cylinders. The Monte Carlo approach makes XRMC able to accurately simulate X-ray photon transport and interactions with matter up to any order of interaction. The differential cross-sections and all other quantities related to the interaction processes (photoelectric absorption, fluorescence emission, elastic and inelastic scattering) are computed using the xraylib software library, which is currently the most complete and up-to-date software library for X-ray parameters. The use of variance reduction techniques makes XRMC able to reduce the simulation time by several orders of magnitude compared to other general-purpose Monte Carlo simulation programs. Running time: It is dependent on the complexity of the simulation. For the examples distributed with the code, it ranges from less than 1 s to a few minutes.

Golosio, Bruno; Schoonjans, Tom; Brunetti, Antonio; Oliva, Piernicola; Masala, Giovanni Luca

2014-03-01

322

Total reflection X-ray fluorescence analysis of trace-elements in candies marketed in Mexico  

NASA Astrophysics Data System (ADS)

Trace metals concentrations in food are significant for nutrition, due either to their nature or toxicity. Sweets, including chewing gum and candies, are not exactly a food, but they usually are unwearied consumed by children, the most vulnerable age-group to any kind of metal contamination in the food chain. The presence of relatively high concentrations of heavy metals such as Lead elicits concern since children are highly susceptible to heavy metals poisoning. Trace-metals concentrations were determined for six different flavors of a Mexican candy by means of Total X-ray Fluorescence Spectrometry. Triplicate samples of the various candy's flavours (strawberry, pineapple, lemon, blackberry, orange and chilli) were digested in 8 mL of a mix of supra-pure HNO 3 and H 2O 2 (6 mL: 2 mL) in a microwave oven MARS-X. Results show the presence of essential and toxic elements such as Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, and Pb. All metal concentrations were higher and significantly different ( ? = 0.05) in chilli candy, compared to other candy flavours. Lead concentration fluctuated in the range of 0.102 to 0.342 ?g g - 1 . A discussion about risk consumption and concentration allowed by Mexican and International Norms is made. As a part of the Quality Control Program, a NIST standard of "Citrus Leaves" and a blank were treated in the same way.

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

2010-06-01

323

Quantitative measurement of PM10 by means of X-ray fluorescence spectra  

NASA Astrophysics Data System (ADS)

We developed an automatic device able to sample and analyze in situ and in real time airborne particulate matter (PM) using the X-ray fluorescence of the chemical species layered on a filter, having atomic numbers between 19 (Potassium) and 82 (Lead). Furthermore, we developed a calibration technique, which gives the parameters for real time automatic determination of the absolute mass of the chemical species present on the sample, with a sensitivity varying from 1 to 100 ?g per sample. Our system could represent a simpler alternative to the complex and sophisticated laboratory measurements, such as Inductively Coupled Plasma Mass Spectrometry (ICP-MS) or Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES), officially used by environmental agencies. A 6 month in-situ test, carried out in collaboration with the local Regional Environmental Agency, showed that our system gives results comparable with the ones obtained using existing techniques, but with smaller errors. The methodology developed has been submitted for a patent.

Busetto, E.; Peloi, M.; Rebuffi, L.; Tefouet Kana, E.

2013-05-01

324

Combined fluorescence and X-Ray tomography for quantitative in vivo detection of fluorophore.  

PubMed

Initial results from a novel dual modality preclinical imager which combines non-contact fluorescence tomography (FT) and x-ray computed tomography (CT) for preclinical functional and anatomical in vivo imaging are presented. The anatomical data from CT provides a priori information to the FT reconstruction to create overlaid functional and anatomical images with accurate localization and quantification of fluorophore distribution. Phantoms with inclusions containing Indocyanine-Green (ICG), and with heterogeneous backgrounds including iodine in compartments at different concentrations for CT contrast, have been imaged with the dual modality FT/CT system. Anatomical information from attenuation maps and optical morphological information from absorption and scattering maps are used as a priori information in the FT reconstruction. Although ICG inclusions can be located without the a priori information, the recovered ICG concentration shows 75% error. When the a priori information is utilized, the ICG concentration can be recovered with only 15% error. Developing the ability to accurately quantify fluorophore concentration in anatomical regions of interest may provide a powerful tool for in vivo small animal imaging. PMID:20082529

Barber, W C; Lin, Y; Nalcioglu, O; Iwanczyk, J S; Hartsough, N E; Gulsen, G

2010-02-01

325

X-ray Fluorescence Spectroscopy Study of Coating Thickness and Base Metal Composition  

NASA Technical Reports Server (NTRS)

For electrical, electronic, and electromechanical (EEE) parts to be approved for space use, they must be able to meet safety standards approved by NASA. A fast, reliable, and precise method is needed to make sure these standards are met. Many EEE parts are coated in gold (Au) and nickel (Ni), and the thickness coating is crucial to a part s performance. A nondestructive method that is efficient in measuring coating thickness is x-ray fluorescence (XRF) spectroscopy. The XRF spectrometer is a machine designed to measure layer thickness and composition of single or multilayered samples. By understanding the limitations in the collection of the data by this method, accurate composition and thickness measurements can be obtained for samples with Au and Ni coatings. To understand the limitations of data found, measurements were taken with the XRF spectrometer and compared to true values of standard reference materials (SRM) that were National Institute of Standards and Technology (NIST) traceable. For every sample, six different parameters were varied to understand measurement error: coating/substrate combination, number of layers, counting interval, collimator size, coating thickness, and test area location. Each measurement was taken in accordance with standards set by the American Society for Testing and Materials (ASTM) International Standard B 568.

Rolin, T. D.; Leszczuk, Y.

2008-01-01

326

[Research on the X-ray fluorescence spectrometry method to determine trace elements in kimberlite].  

PubMed

It is very important to detect trace elements for kilmberlite. Through improving the working conditions of X-ray fluorescence spectrometer and optimizing the analytical conditions, the determination method of trace elements, such as Sc, Cr, Ni, Y, Nb, La, in kimberlite was worked out. The method has been successfully applied to the determination of trace elements in over 2 thousand samples of kimberlite from Liaoning province. The detection limits of the method were relatively low (the detection limit of Sc droped from 9.54 to 2.83 micrograms.g-1 and the detection limit of La droped from 21.68 micrograms.g-1 to 9.18 micrograms.g-1), i.e. 2.83, 2.15, 2.20, 1.17, 1.05 and 9.18 micrograms.g-1 for Sc, Cr, Ni, Y, Nb and La, respectively. The precision of the method was very high with 2.10%-7.09% of RSD (n = 20). Compared with ICP spectrometry this method is satisfactory. The method has proven to be simple and rapid with low cost and high efficiency. PMID:12961906

Zhang, Lei; Yan, Chuan-wei; Lu, Yi

2003-04-01

327

Determination of bromine in regulated foods with a field-portable X-ray fluorescence analyzer.  

PubMed

A field-portable X-ray fluorescence analyzer, factory-calibrated for soil analysis, was used to measure bromine (Br) mass fractions in reference materials, flour, bakery products, malted barley, selected U.S. Food and Drug Administration Total Diet Study foods, and other food products. By using a calibration based on instrumental neutron activation analysis results for Br in reference materials, accurate quantitative results, confirmed by z-scores, could be obtained for mass fractions of about 2-55 mg/kg. These results confirmed accuracy of results (with larger uncertainties) obtained by applying a simple correction factor to the analyzer's output value. Results showed that very short analysis times (<2 min) would be needed to screen foods for Br content at regulatory levels for brominated and enriched brominated flour (24 mg/kg Br) and whole wheat flour and bakery products (36 mg/kg Br). Feasibility for determination of Br in malted barley at the regulatory level (75 mg/kg Br) was demonstrated, but quantitative results at that level could not be assured because no reference material with a suitable mass fraction was available. Br mass fractions for all foods tested were well below regulatory levels. PMID:19485210

Anderson, David L

2009-01-01

328

Hazardous metals in vintage plastic toys measured by a handheld X-ray fluorescence spectrometer.  

PubMed

Over 100 plastic toys from the 1970s and 1980s, both polyvinyl chloride ("vinyl") and nonvinyl, were analyzed in the study described here using a handheld X-ray fluorescence spectrometer to quantify hazardous metal content. A sampling of recent vinyl toys was also tested. The majority of nonvinyl samples were Fisher Price brand toys. The vinyl toys consisted largely of Barbie dolls and other dolls. Overall, lead or cadmium was found in 67% of vintage plastic toys, frequently at concentrations exceeding current U.S. and European limits. Arsenic was detected at levels of concern in 16% of the samples. In the nonvinyl toys, heavy metal content was found to correlate with certain colors of plastic. The likely sources of the detected metals are discussed. None of the contemporary vinyl toys contained detectable cadmium, lead, or arsenic. Given that vintage toys remain in widespread use by children in homes and other locations, the results illuminate a potential source of heavy metal exposure for children. PMID:25619030

Miller, Gillian Zaharias; Harris, Zoe E

2015-01-01

329

Using Synchrotron X-ray Fluorescence Microprobes in the Study of Metal Homeostasis in Plants  

SciTech Connect

Background and Aims: This Botanical Briefing reviews the application of synchrotron X-ray fluorescence (SXRF) microprobes to the plant sciences; how the technique has expanded our knowledge of metal(loid) homeostasis, and how it can be used in the future. Scope: The use of SXRF microspectroscopy and microtomography in research on metal homeostasis in plants is reviewed. The potential use of SXRF as part of the ionomics toolbox, where it is able to provide fundamental information on the way that plants control metal homeostasis, is recommended. Conclusions: SXRF is one of the few techniques capable of providing spatially resolved in-vivo metal abundance data on a sub-micrometre scale, without the need for chemical fixation, coating, drying or even sectioning of samples. This gives researchers the ability to uncover mechanisms of plant metal homeostasis that can potentially be obscured by the artefacts of sample preparation. Further, new generation synchrotrons with smaller beam sizes and more sensitive detection systems will allow for the imaging of metal distribution within single living plant cells. Even greater advances in our understanding of metal homeostasis in plants can be gained by overcoming some of the practical boundaries that exist in the use of SXRF analysis.

Punshon, T.; Guerinot, M; Lanzirotti, A

2009-01-01

330

Using synchrotron X-ray fluorescence microprobes in the study of metal homeostasis in plants  

PubMed Central

Background and Aims This Botanical Briefing reviews the application of synchrotron X-ray fluorescence (SXRF) microprobes to the plant sciences; how the technique has expanded our knowledge of metal(loid) homeostasis, and how it can be used in the future. Scope The use of SXRF microspectroscopy and microtomography in research on metal homeostasis in plants is reviewed. The potential use of SXRF as part of the ionomics toolbox, where it is able to provide fundamental information on the way that plants control metal homeostasis, is recommended. Conclusions SXRF is one of the few techniques capable of providing spatially resolved in-vivo metal abundance data on a sub-micrometre scale, without the need for chemical fixation, coating, drying or even sectioning of samples. This gives researchers the ability to uncover mechanisms of plant metal homeostasis that can potentially be obscured by the artefacts of sample preparation. Further, new generation synchrotrons with smaller beam sizes and more sensitive detection systems will allow for the imaging of metal distribution within single living plant cells. Even greater advances in our understanding of metal homeostasis in plants can be gained by overcoming some of the practical boundaries that exist in the use of SXRF analysis. PMID:19182222

Punshon, Tracy; Guerinot, Mary Lou; Lanzirotti, Antonio

2009-01-01

331

Combined Fluorescence and X-Ray Tomography for Quantitative In Vivo Detection of Fluorophore  

PubMed Central

Initial results from a novel dual modality preclinical imager which combines non-contact fluorescence tomography (FT) and x-ray computed tomography (CT) for preclinical functional and anatomical in vivo imaging are presented. The anatomical data from CT provides a priori information to the FT reconstruction to create overlaid functional and anatomical images with accurate localization and quantification of fluorophore distribution. Phantoms with inclusions containing Indocyanine-Green (ICG), and with heterogeneous backgrounds including iodine in compartments at different concentrations for CT contrast, have been imaged with the dual modality FT/CT system. Anatomical information from attenuation maps and optical morphological information from absorption and scattering maps are used as a priori information in the FT reconstruction. Although ICG inclusions can be located without the a priori information, the recovered ICG concentration shows 75% error. When the a priori information is utilized, the ICG concentration can be recovered with only 15% error. Developing the ability to accurately quantify fluorophore concentration in anatomical regions of interest may provide a powerful tool for in vivo small animal imaging. PMID:20082529

Barber, W. C.; Lin, Y.; Nalcioglu, O.; Iwanczyk, J. S.; Hartsough, N. E.; Gulsen, G.

2010-01-01

332

Monochromatic x-ray radiography for areal-density measurement of inertial fusion energy fuel in fast ignition experiment  

SciTech Connect

Ultrafast, two-dimensional x-ray imaging is an important diagnostics for the inertial fusion energy research, especially in investigating implosion dynamics at the final stage of the fuel compression. Although x-ray radiography was applied to observing the implosion dynamics, intense x-rays emitted from the high temperature and dense fuel core itself are often superimposed on the radiograph. This problem can be solved by coupling the x-ray radiography with monochromatic x-ray imaging technique. In the experiment, 2.8 or 5.2 keV backlight x-rays emitted from laser-irradiated polyvinyl chloride or vanadium foils were selectively imaged by spherically bent quartz crystals with discriminating the out-of-band emission from the fuel core. This x-ray radiography system achieved 24 {mu}m and 100 ps of spatial and temporal resolutions, respectively.

Fujioka, Shinsuke; Fujiwara, Takashi; Tanabe, Minoru; Nishimura, Hiroaki; Nagatomo, Hideo; Ohira, Shinji; Shiraga, Hiroyuki; Azechi, Hiroshi [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita Osaka, 565-0871 (Japan); Inubushi, Yuichi [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2010-10-15

333

Digest of celestial X-ray missions and experiments  

NASA Technical Reports Server (NTRS)

Information on instruments, the platforms that carried them, and the data they gathered is presented. Instrument selection was confined to detectors operating in the 0.20 to 300 keV range. Included are brief descriptions of the spacecraft, experiment packages and missions. Cross-referenced indexes are provided for types of instruments, energy ranges, time spans covered, positional catalogs and observational catalogs. Data sets from these experiments (NSSDC) are described.

Locke, M. C.

1982-01-01

334

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

PubMed

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

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

2005-11-01

335

Performance of HEXTE engineering model phoswich detectors. [High Energy X-ray Timing Experiment  

NASA Technical Reports Server (NTRS)

The preliminary design for the 15-250 keV, 200/sq cm, phoswich detectors for the High Energy X-ray Timing Experiment for NASA's X-ray Timing Explorer mission has been completed, and the first engineering model has been fabricated. This unit has undergone extensive environmental and performance testing, including extended vibration, thermal range, resolution, uniformity, and pulse shape, and is within specifications for all tests. Broad beam energy resolution of better than 15 percent at 60 keV and clear separation of NaI and CsI pulse shape peaks are seen. The design and test results will be presented.

Hink, Paul; Pelling, Michael; Rothschild, Richard

1992-01-01

336

Reflective multilayer optic as hard X-ray diagnostic on laser-plasma experiment  

NASA Astrophysics Data System (ADS)

A multilayer-based optic was tested for use as an X-ray diagnostic on a laser-plasma experiment. The multilayer optic was employed to selectively pass X-rays between 55 and 100 keV. An order of magnitude improvement in signal-to-noise ratio is achieved compared to a transmission crystal spectrometer. A multilayer response model, taking into account the source size and spectral content, is constructed and the outlook for application above 500 keV is briefly discussed. LLNL-JRNL-664311.

Brejnholt, N. F.; Decker, T. A.; Hill, R. M.; Chen, H.; Williams, G. J.; Park, J.; Alameda, J. B.; Fernández-Perea, M.; Pivovaroff, M. J.; Soufli, R.; Descalle, M.-A.; Peebles, J.; Kerr, S. M.

2015-01-01

337

Bragg crystal spectrometer for HEAO-B X-ray astronomy experiment  

NASA Technical Reports Server (NTRS)

The X-ray astronomy experiment for the HEAO mission is described. The instrument to be flown on the satellite consists of two Bragg crystal spectrometers designed to make measurements with high spectral resolution in the energy range from 0.1 to 10 keV. No sharp spectroscopic features were detected directly in X-ray astronomy except emission lines in the sun; therefore, the objectives and design criteria of this instrument are based on the theoretical models of the different types of extra solar X-ray sources. From the point of view of instrumental techniques it is convenient to divide these into point or stellar sources, whose radiation is parallel, and diffuse sources, and to consider the possible spectral features in each type.

Angel, J. R. P.; Woodgate, B. E.

1973-01-01

338

X-ray preheating of window materials in direct-drive shock-wave timing experiments  

SciTech Connect

The optical properties of x-ray preheated planar-window materials relevant for shock-wave timing experiments were studied on the OMEGA Laser System. The x-ray radiation was generated by 100 ps, 1x10{sup 15} W/cm{sup 2} laser pulses incident on planar plastic targets, instantaneously affecting samples located {approx}0.7 mm away. An abrupt onset of strong absorption of an optical probe beam ({lambda}=532 nm) and a temporally varying refractive index were measured in polystyrene and diamond windows. The behavior of diamond windows exposed to x rays is consistent with a simple model based on the generation of free charge carriers. Polystyrene windows showed indications of optical transitions due to molecular states that are created by the ionizing radiation.

Theobald, W.; Miller, J. E.; Boehly, T. R.; Vianello, E.; Meyerhofer, D. D.; Sangster, T. C.; Eggert, J.; Celliers, P. M. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2006-12-15

339

X-ray scattering functions of fractal structures : comparison between simulations and experiments  

E-print Network

polarisabilité des amas. Abstract. - Small angle X-ray scattering (S.A.X.S.) functions of aluminum hydroxide - 82.70D 1. Introduction. 3d aggregation experiments have been performed on aluminum hydroxide species that aluminum hydroxide subunits have anisotropic interactions due to their internal struc- ture, we first

Paris-Sud XI, Université de

340

Neutron and X-ray experiments at high temperature P. Aldebert (*)  

E-print Network

649 Neutron and X-ray experiments at high temperature P. Aldebert (*) LA 302, E.N.S.C.P., 11, rue récemment celle des neutrons sont devenues des sondes puissantes propres à fournir des infor- mations'échantillon avec son environnement, en fait l'atmosphère ambiante et le support de l'échantillon. Les neutrons

Boyer, Edmond

341

Laser-induced fluorescence and X-ray spectral analysis of carious process in hard dental tissues.  

PubMed

Morphological and spectral X-ray analysis of carious and noncarious extracted teeth showed the patterns of dentin ossification in caries of different degree. Parietal ectopic ossification of the canal and cavity lumens in stages III and IV dental caries is regarded as a specific structural marker of pathological regeneration. The X-ray spectral analysis showed that the progress of carious process is paralleled by loss of mineral components. Laser-induced fluorescent study of tissues in extracted teeth showed 4 spectral bands corresponding to mineral and protein components of the tooth. The progress of carious process was associated with reduction of the fluorescence intensities of the spectral bands characteristic of dental collagen and mineral components. PMID:21246104

Lidman, G Yu; Larionov, P M; Savchenko, S V; Lushnikova, E L; Orishich, A M; Rozhin, I A; Malov, A N; Maslov, N A; Titov, A T; Kositsyna, I G

2010-09-01

342

Note: Experiments in hard x-ray chemistry: In situ production of molecular hydrogen and x-ray induced combustion  

SciTech Connect

We have successfully loaded H{sub 2} into a diamond anvil cell at high pressure using the synchrotron x-ray induced decomposition of NH{sub 3}BH{sub 3}. In a second set of studies, radiation-assisted release of O{sub 2} from KCLO{sub 3}, H{sub 2} release from NH{sub 3}BH{sub 3}, and reaction of these gases in a mixture of the reactants to form liquid water using x-rays at ambient conditions was observed. Similar observations were made using a KCLO{sub 3} and NaBH{sub 4} mixture. Depending on reaction conditions, an explosive or far slower reaction producing water was observed.

Pravica, Michael; Bai Ligang; Liu Yu; Galley, Martin; Robinson, John [High Pressure Science and Engineering Center (HiPSEC) and Department of Physics, University of Nevada Las Vegas (UNLV), Las Vegas, Nevada 89154-4002 (United States); Park, Changyong [HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, 9700 South Cass Ave., Argonne, Illinois 60437 (United States); Hatchett, David [Department of Chemistry, University of Nevada Las Vegas (UNLV), Las Vegas, Nevada 89154-4003 (United States)

2012-03-15

343

Estimation of grain size variability with micro X-ray fluorescence in laminated lacustrine sediments, Cape Bounty, Canadian High Arctic  

Microsoft Academic Search

Finely laminated sediment cores from two Arctic lakes were investigated using the Itrax™ Core Scanner that provides micro\\u000a X-ray fluorescence (?-XRF) measurements with a spatial resolution of 100 ?m. We compared these chemical measurements with\\u000a standard geochemical methods using, at the macroscopic scale, inductively coupled plasma–atomic emission spectrometry (ICP-AES)\\u000a and, at the microscopic scale, energy dispersive spectroscopy (EDS). We also investigated

Stéphanie Cuven; Pierre Francus; Scott F. Lamoureux

2010-01-01

344

An X-ray image intensifier for microsecond time-resolved experiments  

NASA Astrophysics Data System (ADS)

Persistence of an X-ray image intensifier with a YAG (P46, Y3Al5O12:Ce3+) phosphor in the output window was examined using X-ray pulses from a storage ring and a high-speed CMOS camera. Because of the fast decay of the YAG fluorescence (60 ns), persistence of CsI:Na+ in the input window dominates the decay of intensity of the image intensifier. As reported before, persistence of CsI:Na+ had two major components when fitted with two exponential functions, a fast one around 600 ns and a slow one about 7 ?s. In addition, it was found that a slower component, which is small but takes tens of microseconds to decay, also exists. Thus, this detector should be used with caution at a time resolution higher than about 50 ?s when high accuracy of measurement is required.

Yagi, N.; Aoyama, K.

2015-01-01

345

Phase relations in partially molten lower mantle material investigated in-situ by X-ray fluorescence  

NASA Astrophysics Data System (ADS)

It is widely accepted that the early Earth was partially molten due to the high energy dissipated by terrestrial accretion and giant meteoritic impacts. After core formation, subsequent cooling of the magma ocean has led to fractional crystallization of the primitive mantle. Melting relations of silicates have been extensively investigated using the multi-anvil press, for pressures between 3 and 25 GPa [1, 2]. Using the quench technique, it has been shown that the pressure affects significantly the solidus and liquidus curves, and most probably the composition of the eutectic liquid. At higher pressures, the use of laser-heated diamond anvil cell (LH-DAC) technique is required with the intrinsic limitation of very small samples recovered, which gives rise to higher experimental uncertainties for the chemical analysis. We propose a new in-situ method, based on the use of geochemical tracers, to determine the melting relations at lower mantle conditions of pressure and temperature. First, we investigated partial melting up to more than 3000K, for pressures between 25 and up to more than 100 GPa, using LH-DAC coupled with angle dispersive X-ray diffraction at the ID27 beamline of the ESRF [3]. The starting material of chondritic composition resulted in an assemblage of (Mg,Fe)SiO3 perovskite, (Mg,Fe)O ferropericlase and CaSiO3 perovskite. Partial melting was evidenced from (i) disappearance on the 2D diffraction images of sets of diffraction rings representative of a given mineral, (ii) changes in diffraction intensities for the integrated patterns, and (iii) changes in the relation between sample-temperature and laser-power. For a given temperature condition, once partial melting has been evidenced, we kept constant temperature for several minutes in order to enable chemical segregation in the laser power; elements participating to the melt are expected to migrate preferentially and concentrate at the centre of the laser hot spot, while solid species should remain at the edge of the partially melted zone. After the quench, X-ray diffraction was performed at several sample positions, with a spatial resolution better than 2x3?m, in order to retrieve the phase contents as a function of position relative to the YAG-laser spot. It provides a map of phase contents. At the same sample positions, we also recorded X-ray fluorescence spectra using an energy dispersive solid-state Si(Li) (Vortex) set at ~30° to the incident beam. Using incident beam energy of ~33 keV, we detected K-fluorescence of Fe, Ca and Si major elements. We also detected L-lines of other elements, Rb, Y, and Zr, which were added at levels of several ppm to the starting material prior to the high pressure experiment. Quantitative elemental contents are derived from fluorescence spectra using the PyMca program [4]; it provides maps of elemental fraction that can be correlated with the phase fractions.

Lo Nigro, G.; Andrault, D.; Petitgirard, S.; Garbarino, G.

2009-12-01

346

A fluorescence XAFS measurement instrument in the soft x-ray region toward observation under operando conditions  

NASA Astrophysics Data System (ADS)

X-ray absorption fine structure (XAFS) measurements are widely used for the analysis of electronic structure. Generally, XAFS in the soft X-ray region is measured under vacuum, but chemical structures under vacuum are typically different from those under operando conditions, where chemical species exhibit their function. Here, we developed an XAFS measurement instrument, as a step toward operando fluorescent, which yields XAFS measurement using synchrotron radiation in the soft X-ray region. We applied this method to analyze the local electronic structure of the sulfur atoms in L-cysteine in different pH solutions. In water at pH 7, the hydrogen atom does not dissociate from the thiol (-SH) group in L-cysteine, which forms a structure surrounded by and interacting with water molecules. The XAFS spectrum of L-cysteine in solution was altered by changing the pH. At pH 9, the hydrogen atom dissociated and a thiolate anion was formed. Although the -SH group was oxidized to SO42- when L-cysteine was adsorbed on a metal surface and dried, no oxidation was observed in solution. This may be because the water molecules were densely packed and protected the -SH group from oxidation. Our results show that this instrument aimed toward operando fluorescence XAFS measurements in the soft X-ray region is useful for structural analysis of sulfur atoms in organic molecules in air and in solution. The instrument will be applied to the structural analysis of materials containing elements that have absorption edges in soft X-ray region, such as phosphorus and alkali metals (potassium and cesium). It will be also particularly useful for the analysis of samples that are difficult to handle under vacuum and materials that have specific functions in solution.

Honda, M.; Baba, Y.; Shimoyama, I.; Sekiguchi, T.

2015-03-01

347

Improved signal-to-noise ratio for non-perpendicular detection angles in x-ray fluorescence computed tomography (XFCT)  

NASA Astrophysics Data System (ADS)

The standard imaging setup in x-ray fluorescence computed tomography detects the fluorescence emission at a right angle with respect to the axis of the excitation beam. In this paper we have studied how the detection angle affects the signal-to-noise ratio (S/N), which is a major factor influencing the low-contrast sensitivity of the imaging system. This is done for an imaging setup using a collimated detector and a pencil beam of excitation x-rays. An ideal detection process is simulated for a generalized imaging case with gold/platinum tracers and experimental measurements are performed using a diagnostic x-ray tube. For monochromatic excitation, the results indicate that order-of-magnitude improvements of the S/N can be achieved by optimizing the detection angle. The maximal S/N, when exciting with an energy just above the K-edge, is achieved for large detection angles, i.e. with the detector close to the source. The improvements also transfer to polychromatic excitation sources and the experimental results show up to four-fold improvements of the S/N when changing the detection angle from 90° to 150°. Also, the changes of the S/N behavior when switching the fluorescent tracer is briefly demonstrated. These results suggest that the choice of detection angle should be taken seriously in the design of future XFCT imaging systems.

Sjölin, Martin; Danielsson, Mats

2014-11-01

348

Improved signal-to-noise ratio for non-perpendicular detection angles in x-ray fluorescence computed tomography (XFCT).  

PubMed

The standard imaging setup in x-ray fluorescence computed tomography detects the fluorescence emission at a right angle with respect to the axis of the excitation beam. In this paper we have studied how the detection angle affects the signal-to-noise ratio (S/N), which is a major factor influencing the low-contrast sensitivity of the imaging system. This is done for an imaging setup using a collimated detector and a pencil beam of excitation x-rays. An ideal detection process is simulated for a generalized imaging case with gold/platinum tracers and experimental measurements are performed using a diagnostic x-ray tube. For monochromatic excitation, the results indicate that order-of-magnitude improvements of the S/N can be achieved by optimizing the detection angle. The maximal S/N, when exciting with an energy just above the K-edge, is achieved for large detection angles, i.e. with the detector close to the source. The improvements also transfer to polychromatic excitation sources and the experimental results show up to four-fold improvements of the S/N when changing the detection angle from 90° to 150°. Also, the changes of the S/N behavior when switching the fluorescent tracer is briefly demonstrated. These results suggest that the choice of detection angle should be taken seriously in the design of future XFCT imaging systems. PMID:25310695

Sjölin, Martin; Danielsson, Mats

2014-11-01

349

Energy dispersive X-ray fluorescence determination of cadmium in uranium matrix using Cd K? line excited by continuum  

NASA Astrophysics Data System (ADS)

An energy dispersive X-ray fluorescence method for determination of cadmium (Cd) in uranium (U) matrix using continuum source of excitation was developed. Calibration and sample solutions of cadmium, with and without uranium were prepared by mixing different volumes of standard solutions of cadmium and uranyl nitrate, both prepared in suprapure nitric acid. The concentration of Cd in calibration solutions and samples was in the range of 6 to 90 µg/mL whereas the concentration of Cd with respect to U ranged from 90 to 700 µg/g of U. From the calibration solutions and samples containing uranium, the major matrix uranium was selectively extracted using 30% tri-n-butyl phosphate in dodecane. Fixed volumes (1.5 mL) of aqueous phases thus obtained were taken directly in specially designed in-house fabricated leak proof Perspex sample cells for the energy dispersive X-ray fluorescence measurements and calibration plots were made by plotting Cd K? intensity against respective Cd concentration. For the calibration solutions not having uranium, the energy dispersive X-ray fluorescence spectra were measured without any extraction and Cd calibration plots were made accordingly. The results obtained showed a precision of 2% (1 ?) and the results deviated from the expected values by < 4% on average.

Dhara, Sangita; Misra, N. L.; Aggarwal, S. K.; Venugopal, V.

2010-06-01

350

Chemical Composition and Heterogeneity of Wild 2 Cometary Particles Determined by Synchrotron X-ray Fluorescence  

SciTech Connect

Seven cometary dust particle tracks in Stardust aerogel were studied using synchrotron X-ray fluorescence methods at the National Synchrotron Light Source (NY) and Advanced Photon Source (IL). Elemental maps were produced for each of the tracks and elemental abundances for 156 individual fragments within these tracks were determined. Whole-track elemental abundances were inferred by summing the elemental masses for the fragments in each track and scaling by the ratio of total Fe in the map and total Fe in the fragments. In general, whole-track and terminal-particle abundances are dissimilar. The total Fe masses ranged from 4 to 2200 pg, corresponding to impactors in the size range of 2.7 to 22 {mu}m if Fe abundances are equal to the chondritic value. Systematic variations in element abundance with fragment distance from the aerogel entry point were generally subtle but were pronounced in one track (C2115,19). In this track, Zn/Fe was about three orders of magnitude higher at the top, Cr/Fe was two orders of magnitude higher at the bottom, and S was relatively uniform. Compositional convergence data showed that typically analysis of {approx}10 fragments was needed to reach convergent whole-track abundance. Zinc was an exception, showing nonconvergent profiles and steps due to the presence of rare, high-Zn fragments. The resulting wholetrack elemental abundances show diverse patterns that are generally chondritic (i.e., within a factor of three of CI abundances) with some exceptions, notably depletions in S and enrichments in the moderately volatile elements Cu, Zn, and Ga. Enrichments in large ion lithophile elements relative to Fe were observed in one track. Correlation matrices showed several strong elemental correlations, notably selenium associated with sulfur (sulfides), a ubiquitous correlation of the first-row transition metals Cr, Mn, and Fe attributed to the presence of pyroxene, and enrichments of gallium associated with calcium, likely affiliated with Mg-Al glass.

Lanzirotti,A.; Sutton, S.; Flynn, G.; Newville, M.; Rao, W.

2008-01-01

351

Chemical composition and heterogeneity of Wild 2 cometary particles determined by synchrotron X-ray fluorescence  

NASA Astrophysics Data System (ADS)

Seven cometary dust particle tracks in Stardust aerogel were studied using synchrotron X-ray fluorescence methods at the National Synchrotron Light Source (NY) and Advanced Photon Source (IL). Elemental maps were produced for each of the tracks and elemental abundances for 156 individual fragments within these tracks were determined. Whole-track elemental abundances were inferred by summing the elemental masses for the fragments in each track and scaling by the ratio of total Fe in the map and total Fe in the fragments. In general, whole-track and terminal-particle abundances are dissimilar. The total Fe masses ranged from 4 to 2200 pg, corresponding to impactors in the size range of 2.7 to 22 ?m if Fe abundances are equal to the chondritic value. Systematic variations in element abundance with fragment distance from the aerogel entry point were generally subtle but were pronounced in one track (C2115,19). In this track, Zn/Fe was about three orders of magnitude higher at the top, Cr/Fe was two orders of magnitude higher at the bottom, and S was relatively uniform. Compositional convergence data showed that typically analysis of ~10 fragments was needed to reach convergent whole-track abundance. Zinc was an exception, showing nonconvergent profiles and steps due to the presence of rare, high-Zn fragments. The resulting wholetrack elemental abundances show diverse patterns that are generally chondritic (i.e., within a factor of three of CI abundances) with some exceptions, notably depletions in S and enrichments in the moderately volatile elements Cu, Zn, and Ga. Enrichments in large ion lithophile elements relative to Fe were observed in one track. Correlation matrices showed several strong elemental correlations, notably selenium associated with sulfur (sulfides), a ubiquitous correlation of the first-row transition metals Cr, Mn, and Fe attributed to the presence of pyroxene, and enrichments of gallium associated with calcium, likely affiliated with Mg-Al glass.

Lanzirotti, A.; Sutton, S. R.; Flynn, G. J.; Newville, M.; Rao, W.

2008-02-01

352

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

SciTech Connect

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 the elements Si, Mn, Fe, Ni, and Zn in individual aquatic protist cells. This technique distinguishes between different types of cells in an assemblage and between cells and other particulate matter. Under typical operating conditions, the minimum detection limits are 7.0 x 10{sup -16} mol {mu}m{sup -2} for Si and between 5.0 x 10{sup -20} and 3.9 x 10{sup -19} mol {mu}m{sup -2} for Mn, Fe, Ni, and Zn; this sensitivity is sufficient to detect these elements in cells from even the most pristine waters as demonstrated in phytoplankton cells collected from remote areas of the Southern Ocean. Replicate analyses of single cells produced variations of <5% for Si, Mn, Fe, and Zn and <10% for Ni. Comparative analyses of cultured phytoplankton cells generally show no significant differences in cellular metal concentrations measured with SXRF and standard bulk techniques (spectrophotometry and graphite furnace atomic absorption spectrometry). SXRF also produces two-dimensional maps of element distributions in cells, thereby providing information not available with other analytical approaches. This technique enables the accurate and precise measurement of trace metals in individual aquatic protists collected from natural environments.

Twining, B. S.; Baines, S. B.; Fisher, N. S.; Maser, J.; Vogt, S.; Jacobsen, C.; Tovar-Sanchez, A.; Sanudo-Wihelmy, S. A.; Experimental Facilities Division (APS); Stony Brook Univ.

2003-01-01

353

X-Ray Fluorescence Imaging: A New Tool for Studying Manganese Neurotoxicity  

PubMed Central

The neurotoxic effect of manganese (Mn) establishes itself in a condition known as manganism or Mn induced parkinsonism. While this condition was first diagnosed about 170 years ago, the mechanism of the neurotoxic action of Mn remains unknown. Moreover, the possibility that Mn exposure combined with other genetic and environmental factors can contribute to the development of Parkinson's disease has been discussed in the literature and several epidemiological studies have demonstrated a correlation between Mn exposure and an elevated risk of Parkinson's disease. Here, we introduce X-ray fluorescence imaging as a new quantitative tool for analysis of the Mn distribution in the brain with high spatial resolution. The animal model employed mimics deficits observed in affected human subjects. The obtained maps of Mn distribution in the brain demonstrate the highest Mn content in the globus pallidus, the thalamus, and the substantia nigra pars compacta. To test the hypothesis that Mn transport into/distribution within brain cells mimics that of other biologically relevant metal ions, such as iron, copper, or zinc, their distributions were compared. It was demonstrated that the Mn distribution does not follow the distributions of any of these metals in the brain. The majority of Mn in the brain was shown to occur in the mobile state, confirming the relevance of the chelation therapy currently used to treat Mn intoxication. In cells with accumulated Mn, it can cause neurotoxic action by affecting the mitochondrial respiratory chain. This can result in increased susceptibility of the neurons of the globus pallidus, thalamus, and substantia nigra pars compacta to various environmental or genetic insults. The obtained data is the first demonstration of Mn accumulation in the substantia nigra pars compacta, and thus, can represent a link between Mn exposure and its potential effects for development of Parkinson's disease. PMID:23185282

Robison, Gregory; Zakharova, Taisiya; Fu, Sherleen; Jiang, Wendy; Fulper, Rachael; Barrea, Raul; Marcus, Matthew A.; Zheng, Wei; Pushkar, Yulia

2012-01-01

354

THE SAP3 COMPUTER PROGRAM FOR QUANTITATIVE MULTIELEMENT ANALYSIS BY ENERGY DISPERSIVE X-RAY FLUORESCENCE  

SciTech Connect

SAP3 is a dual-function FORTRAN computer program which performs peak analysis of energy-dispersive x-ray fluorescence spectra and then quantitatively interprets the results of the multielement analysis. It was written for mono- or bi-chromatic excitation as from an isotopic or secondary excitation source, and uses the separate incoherent and coherent backscatter intensities to define the bulk sample matrix composition. This composition is used in performing fundamental-parameter matrix corrections for self-absorption, enhancement, and particle-size effects, obviating the need for specific calibrations for a given sample matrix. The generalized calibration is based on a set of thin-film sensitivities, which are stored in a library disk file and used for all sample matrices and thicknesses. Peak overlap factors are also determined from the thin-film standards, and are stored in the library for calculating peak overlap corrections. A detailed description is given of the algorithms and program logic, and the program listing and flow charts are also provided. An auxiliary program, SPCAL, is also given for use in calibrating the backscatter intensities. SAP3 provides numerous analysis options via seventeen control switches which give flexibility in performing the calculations best suited to the sample and the user needs. User input may be limited to the name of the library, the analysis livetime, and the spectrum filename and location. Output includes all peak analysis information, matrix correction factors, and element concentrations, uncertainties and detection limits. Twenty-four elements are typically determined from a 1024-channel spectrum in one-to-two minutes using a PDP-11/34 computer operating under RSX-11M.

Nielson,, K. K.; Sanders,, R. W.

1982-04-01

355

Total reflection of x-ray fluorescence (TXRF): a mature technique for environmental chemical nanoscale metrology  

NASA Astrophysics Data System (ADS)

Total reflection x-ray fluorescence (TXRF) is a technique well established for chemical analysis of samples deposited as a thin layer. Nowadays it is mainly employed for electronic industry quality control. Recently, very compact and economic TXRF instrumentation was proposed. Combining this with the capability to analyze liquid samples, this technique is suitable to be employed in many different applications, comprising the very critical field of environmental analysis. Comparisons with the standard atomic absorption spectroscopy (AAS) technique show that TXRF is a practical, accurate, and reliable technique. Indeed, round-robin activities have already been started. Despite the efficiency and economy of the developed portable TXRF instrumentation, this is not widely employed for chemical laboratory analysis probably because TXRF is not an officially recognized technique, i.e. it is not yet normative-subjected. This fact could also be due to the long background of analytical applications developed for AAS, ICPS or inductively coupled plasma mass spectroscopy (ICP-MS) up to now. In this paper, we present a work of environmental monitoring of an industrial site, performed by means of bioindicators (lichens). The analysis of trace elements concentration in lichen was usually conducted with spectrophotometric techniques, such as AAS and ICP-MS, which were accepted by common regulations and normative-subjected. In this study, we accomplished a comparative lichen analysis by AAS and TXRF. The reproducibility of the obtained results showed the high correspondence between the two techniques. This comparison highlighted the versatility of the TXRF apparatus that allowed more rapid and simultaneous element detection. The obtained results suggested that this portable TXRF system could be suitable for regulation to produce certificated analysis upto ppb concentrations for some elements.

Borgese, L.; Zacco, A.; Bontempi, E.; Colombi, P.; Bertuzzi, R.; Ferretti, E.; Tenini, S.; Depero, L. E.

2009-08-01

356

A correlation of breast cancer and calcium levels in hair analyzed by X-ray fluorescence.  

PubMed

Time variations of elemental concentrations and their abnormalities due to breast cancer have been observed along single hair strands by X-ray fluorescence excited by synchrotron radiation. The renal-controlled elements Ca, Sr, S, K, Cl, Br and P have upper and lower levels associated with gating and closing of ion channels in the hair-making cells. The Ca lower level is normal. In cases of Ca deficiency, with a decrease from the normal, store-operated Ca channel gating occurs so as to keep the hair Ca at the normal, and paradoxically high Ca levels near or at the upper level are produced by PTH-operated channel gating of the cells. Chronic Ca deficiency shows a temporal pattern along the hair consisting of a long-term duration of the upper [Ca] level, 10-month long decay to the lower level and abrupt increase to the upper level. The observation for hair from breast-cancer patients also shows the upper Ca level for the time period well before detection, and suggests that cancer is always generated at the long-lasting [Ca] upper level and the hair [Ca] decreases gradually toward the lower level with the cancer growth. This decay of [Ca] is accompanied by those of [Sr] and [K]. Their different decay forms can be explained by parathyroid hormone related peptide (PTHrP) in serum secreted from the cancer having 150 times longer dwell time on the PTH receptors than that of PTH. Patient hair has a memory for the entire cancer process from the state before cancer generation, and the pattern can be distinguished from concentration variation due to the chronic Ca deficiency without cancer, leading to a criterion for cancer detection by the ratio of [Sr]/[Ca]. The hair analysis is useful for early detection of cancer. PMID:25265920

Chikawa, Jun-ichi; Mouri, Yoshitaka; Shima, Hiroki; Yamada, Kousaku; Yamamoto, Hitoshi; Yamamoto, Shingo

2014-01-01

357

Determination of sulphur in uranium matrix by total reflection X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

The possibility of sulphur determination in uranium matrix by total reflection x-ray fluorescence spectrometry (TXRF) has been studied. Calibration solutions and samples of sulphur in uranium matrix were prepared by mixing uranium in form of a standard uranyl nitrate solution and sulphur in the form of Na 2SO 4 standard solution, prepared by dissolving Na 2SO 4 in Milli-Q water. For major element analysis of sulphur, it was determined without separation of uranium whereas for the trace level determinations, uranium was first separated by solvent extraction using 30% tri-n-butyl phosphate (TBP) in dodecane as an extractant. In order to countercheck the TXRF results, a few samples of Rb 2U(SO 4) 3, a chemical assay standard for uranium, were diluted to different dilutions and sulphur content in these solutions were determined. The TXRF determined results for trace determinations of sulphur in these diluted solutions were counterchecked after addition of another uranium solution, so that sulphur is at trace level compared to uranium, separating uranium from these solution mixtures using TBP extraction and determining sulphur in aqueous phase by TXRF. For such TXRF determinations, Co was used as internal standard and W L? was used as excitation source. The precision and accuracy of the method was assessed for trace and major element determinations and was found to be better than 8% (1 ? RSD) and 15% at a concentration level of 1 ?g/mL of sulphur measured in solutions whereas for Rb 2U(SO 4) 3, these values were found to be better than 4 and 13%, respectively.

Dhara, Sangita; Misra, N. L.; Aggarwal, S. K.

2008-12-01

358

X-ray fluorescence imaging of the hippocampal formation after manganese exposure.  

PubMed

Manganese (Mn) intoxication results in neurological conditions similar, but not identical, to idiopathic Parkinson's disease. While the mechanism(s) by which Mn exposure leads to neurotoxic effects remains unclear, studies by magnetic resonance imaging demonstrate a high Mn accumulation in the hippocampal formation (HPCf) of the brain. Metal quantification using this method is not possible. Using X-ray fluorescence imaging, we measured the distribution of Mn in the HPCf for a rodent model of chronic Mn exposure and quantitatively compared it with distributions of other biologically relevant metals. We found considerable increases in average Mn concentrations in all analyzed areas and we identified the dentate gyrus (DG) and the cornus ammonis 3 (CA3) layer as areas accumulating the highest Mn content (?1.2 ?g Mn per g tissue). The DG is significantly enriched with iron (Fe), while the CA3 layer has high zinc (Zn) content. Additionally, significant spatial correlations were found for Mn-Zn concentrations across the HPCf substructures and for Mn-Fe concentrations in the DG. Combined results support that at least two mechanisms may be responsible for Mn transport and/or storage in the brain, associated with either Fe or Zn. Subcellular resolution images of metal distribution in cells of the CA3 show diffuse Mn distributions consistent with Mn localization in both the cytoplasm and nucleus. Mn was not increased in localized intracellular Fe or copper accumulations. A consistent Mn-Zn correlation both at the tissue (40 ?m × 40 ?m) and cellular (0.3 ?m × 0.3 ?m) levels suggests that a Zn transport/storage mechanism in the HPCf is likely associated with Mn accumulation. PMID:23999853

Robison, Gregory; Zakharova, Taisiya; Fu, Sherleen; Jiang, Wendy; Fulper, Rachael; Barrea, Raul; Zheng, Wei; Pushkar, Yulia

2013-11-01

359

Analysis of limestones and dolomites by x-ray fluorescence spectroscopy  

SciTech Connect

Sources of calcium are generally widespread and quite extensive. These sources are limestone, dolomite, marl, chalk, and oyster shell. Cement plants account for nearly half of the demand, while two hundred lime plants in the US and Puerto Rico consume about twenty five percent. Since the chemical composition of the limestone and other sources of calcium is critical in the cement and lime industry, particularly for the deleterious compounds such as sodium oxide, Na{sub 2}O, magnesium oxide, MgO, phosphorus pentoxide, P{sub 2}O{sub 5}, and potassium oxide, K{sub 2}O, accurate determinations are critical. Due to the tonnage per hour, these determinations must be made rapidly and accurately. X-ray fluorescence can thereby satisfy this need for accuracy and also precision. Production of lime is performed by calcining limestone or dolomite in which the industry is generally located and concentrated in the States of Michigan and Pennsylvania. The resulting product is quicklime, CaO, and hydrated lime, Ca(OH){sub 2}. Substantial amounts of quicklime is further processed into calcium carbide in order to produce acetylene gas. In this case, the determination of P{sub 2}O{sub 5} is critical since minor quantities of phosphorus in acetylene gas can cause premature explosions. Other uses for lime are well known in the treatment of water, the paper and pulp industry, and in the steel industry for the production of slag to remove impurities. Dolomitic lime is heavily utilized in the manufacture of magnesite refractories by reacting dolomitic lime with brines from the Michigan Basin to produce magnesium oxide, MgO, and calcium chloride, CaCl{sub 2}. Sample preparation for these materials usually is performed by grinding and pelletizing or fusion with lithium-tetra-borate, Li{sub 2}B{sub 4}O{sub 7}.

Wheeler, B.D.

1999-07-01

360

X-ray fluorescence analysis of rare earth elements in rocks using low dilution glass beads.  

PubMed

Major and trace elements (Na, Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, Rb, Sr, Y, Zr, La, Ce, Pr, Nd, Sm, Gd, Dy, Th and U) in igneous rocks were assayed with fused lithium borate glass beads using X-ray fluorescence spectrometry. Low dilution glass beads, which had a 1:1 sample-to-flux ratio, were prepared for determination of rare earth elements. Complete vitrification of 1:1 mixture required heating twice at 1200 degrees C with agitation. Extra pure reagents containing determinants were used for calibrating standards instead of the rock standard. The calibration curves of the 23 elements showed good linearity. Furthermore, the lower limits of detection corresponding to three times the standard deviation for blank measurements were 26 mass ppm for Na2O, 6.7 for MgO, 4.5 for Al2O3, 4.5 for SiO2, 18 for P2O5, 1.1 for K2O, 4.0 for CaO, 3.9 for TiO2, 1.6 for MnO, 0.8 for Fe2O3, 0.5 for Rb, 0.2 for Sr, 0.4 for Y, 0.5 for Zr, 3.3 for La, 6.5 for Ce, 2.7 for Pr, 2.1 for Nd, 1.7 for Sm, 0.7 for Gd, 2.7 for Dy, 0.5 for Th, and 0.6 for U. Using the present method, we determined the contents of these 23 elements in four rhyolitic and granitic rocks from Japan. PMID:16038502

Nakayama, Kenichi; Nakamura, Toshihiro

2005-07-01

361

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

NASA Astrophysics Data System (ADS)

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

Barber, John

2011-03-01

362

Determination of rare earth impurities in cerium dioxide and oxalate by X-ray fluorescence technique  

Microsoft Academic Search

A method for the determination of lathanum, praseodymium, neodymium and samarium oxides in cerium dioxide has been developed.\\u000a The sample in the oxalate form is mixed with the binding material (boric acid) in the ratio 1?1 pressed to form a double layer\\u000a pellet over a boric acid backing pellet and irradiated by X-rays from a tungsten tube. The secondary X-rays

L. C. Chandola; I. J. Machado; A. N. Mohile

1976-01-01

363

Hard X-ray Fluorescence Microscopy to Determine the Element Distribution of Soil Colloids in Aqueous Environment  

NASA Astrophysics Data System (ADS)

A prominent feature of soil colloids is their huge specific surface. It determines colloidal properties such as adsorption capacity or diffusion. The colloidal interactions differ significantly from the behavior of the same materials in a bulk system. Interactions in the colloidal regime are crucial, for example, for the transport and release of nutrients and toxicants in soils, which then influences directly the growth of plants. However, there is still a need for more analytical resources to study those interactions. To reveal the correlation of the particular trace elements and their distribution in correlation to colloidal interactions as well as changing pH values, experiments at the hard x-ray fluorescence microprobe at beamline 2-ID-E of the Advanced Photon Source (APS), were performed with colloidal clay and soil samples in an aqueous environment as naturally relevant. To obtain further spatial information, stereo imaging has been used. To study the dynamical behavior of these colloidal suspensions at changing pH, a wet sample chamber allowing in situ manipulation was developed and utilized.

Gleber, S.-C.; Vogt, S.; Niemeyer, J.; Finney, L.; McNulty, I.; Thieme, J.

2011-09-01

364

Versatile plug flow catalytic cell for in situ transmission/fluorescence x-ray absorption fine structure measurements  

SciTech Connect

A novel flow-through catalytic cell has been developed for in situ x-ray absorption spectroscopy (XAS) experiments on heterogeneous catalysts under working conditions and in the presence of a liquid and a gas phase. The apparatus allows to carry out XAS measurements in both the transmission and fluorescence modes, at moderate temperature (from RT to 50-80 Degree-Sign C) and low-medium gas pressure (up to 7-8 bars). The materials employed are compatible with several chemicals such as those involved in the direct synthesis of hydrogen peroxide (O{sub 2}, H{sub 2}, H{sub 2}O{sub 2}, methanol). The versatile design of the cell allows to fit it to different experimental setups in synchrotron radiation beamlines. It was used successfully for the first time to test nanostructured Pd catalysts during the direct synthesis of hydrogen peroxide (H{sub 2}O{sub 2}) in methanol solution from dihydrogen and dioxygen.

Centomo, P.; Zecca, M. [Dipartimento di Scienze Chimiche, via Marzolo 1, Universita degli Studi di Padova, 35131 Padova (Italy); Meneghini, C. [Dipartimento di Scienze, via della Vasca Navale 84, Universita di Roma TRE, 00146 Roma (Italy)

2013-05-15

365

Conventional X-ray fluorescence camera with a cadmium-telluride detector and its application to cancer diagnosis  

NASA Astrophysics Data System (ADS)

X-ray fluorescence (XRF) analysis is useful for mapping various molecules in objects. Bremsstrahlung X-rays are selected using a 3.0-mm-thick aluminum filter, and these rays are absorbed by iodine, cerium, and gadolinium molecules in objects. Next, XRF is produced from the objects, and photons are detected by a cadmium-telluride detector. The K? photons are discriminated using a multichannel analyzer, and the number of photons is counted by a counter card. The objects are moved and scanned by an x- y stage in conjunction with a two-stage controller, and X-ray images obtained by molecular mapping are shown on a personal computer monitor. The scan steps of x and y axes were both 2.5 mm, and the photon-counting time per mapping point was 0.5 s. We carried out molecular mapping using the X-ray camera, and K? photons from cerium and gadolinium molecules were produced from cancerous regions in nude mice.

Enomoto, Toshiyuki; Sato, Eiichi; Abderyim, Purkhet; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Watanabe, Manabu; Nagao, Jiro; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2011-04-01

366

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

PubMed

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

Ohata, Masaki; Kidokoro, Toshihiro; Hioki, Akiharu

2012-01-01

367

Development of soft x-ray tracer diagnostics for hohlraum experiments  

Microsoft Academic Search

The purpose of this report is to summarize work performed by the University of Wisconsin during fiscal year 1996 under the NLUF contract DE-FG-96SF21015. This contract involved the development of soft x-ray spectral diagnostics from tracer layers in hohlraum witness plates. This effort was originally intended to be focused on OMEGA experiments, but the experiments were changed to NOVA because

J. J. MacFarlane; D. H. Cohen; P. Wang; R. R. Peterson; G. A. Moses

1998-01-01

368

X-Ray Spectrometer Experiment Aboard the ISEE-C (Heliocentric) Spacecraft  

Microsoft Academic Search

This experiment is designed to provide continuous coverage of solar flare X-ray bursts and transient cosmic gamma-ray bursts. A proportional counter and a scintillation detector together cover the energy range from 5 to 228 keV with good sensitivity, large dynamic range, and high temporal resolution. This experiment provides data storage capability and good absolute timing so that in conjunction with

K. A. Anderson; S. R. Kane; J. H. Primbsch; R. H. Weitzmann; W. D. Evans; R. W. Klebesadel; W. P. Aiello

1978-01-01

369

X-ray diagnostics for ultrashort laser produced plasma experiments (abstract)  

SciTech Connect

The characterization of subpicosecond laser produced plasmas is currently being investigated by the Livermore ultrashort pulse laser group. A 800-nm, 150-fs, 35-mJ laser is focused to a 7-{mu}m spot on solid aluminum targets, producing XUV ({lt}1 keV), {ital K} shell (1.5--30 keV), and hard ({ge}3.0 keV) x-ray emission. The {ital K}-shell emission is studied using a Von Hamos crystal spectrograph with a KAP crystal curved to an 80-mm radius, resulting in a calculated resolution of {ital E}/{Delta}{ital E}{approx}400. The dispersed x rays are detected with a microchannel plate intensified reticon detector which relays the images out of the chamber and displayed on a computer monitor. The hard x rays are monitored with an array of filter x-ray diodes, covering energies from 3 to 75 keV. The XUV emission is monitored with a variably spaced line grating, flat field spectrometer, and a grazing incidence spectragraph. The diagnostics will be presented along with current data from experiments. This work was performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.

Shepherd, R.; Price, D.; Nathel, H.; White, W.; Slaughter, D.; Stewart, R. (Lawrence Livermore National Laboratory, Livermore, California 94550 (United States))

1992-10-01

370

Furthering the understanding of silicate-substitution in ?-tricalcium phosphate: an X-ray diffraction, X-ray fluorescence and solid-state nuclear magnetic resonance study.  

PubMed

High-purity (SupT) and reagent-grade (ST), stoichiometric and silicate-containing ?-tricalcium phosphate (?-TCP: ST0/SupT0 and Si-TCP x=0.10: ST10/SupT10) were prepared by solid-state reaction based on the substitution mechanism Ca3(PO4)(2-x)(SiO4)x. Samples were determined to be phase pure by X-ray diffraction (XRD), and Rietveld analysis performed on the XRD data confirmed inclusion of Si in the ?-TCP structure as determined by increases in unit cell parameters; particularly marked increases in the b-axis and ?-angle were observed. X-ray fluorescence (XRF) confirmed the presence of expected levels of Si in Si-TCP compositions as well as significant levels of impurities (Mg, Al and Fe) present in all ST samples; SupT samples showed both expected levels of Si and a high degree of purity. Phosphorus ((31)P) magic-angle-spinning solid-state nuclear magnetic resonance (MAS NMR) measurements revealed that the high-purity reagents used in the synthesis of SupT0 can resolve the 12 expected peaks in the (31)P spectrum of ?-TCP compared to the low-purity ST0 that showed significant spectral line broadening; line broadening was also observed with the inclusion of Si which is indicative of induced structural disorder. Silicon ((29)Si) MAS NMR was also performed on both Si-TCP samples which revealed Q(0) species of Si with additional Si Q(1)/Q(2) species that may indicate a potential charge-balancing mechanism involving the inclusion of disilicate groups; additional Q(4) Si species were also observed, but only for ST10. Heating and cooling rates were briefly investigated by (31)P MAS NMR which showed no significant line broadening other than that associated with the emergence of ?-TCP which was only realised with the reagent-grade sample ST0. This study provides an insight into the structural effects of Si-substitution in ?-TCP and could provide a basis for understanding how substitution affects the physicochemical properties of the material. PMID:24287162

Duncan, J; Hayakawa, S; Osaka, A; MacDonald, J F; Hanna, J V; Skakle, J M S; Gibson, I R

2014-03-01

371

Determination of trace elements in bee honey, pollen and tissue by total reflection and radioisotope X-ray fluorescence spectrometry  

NASA Astrophysics Data System (ADS)

Multielemental determinations in samples of various types of bee honey, pollen and bee tissue have been carried out using total reflection X-ray fluorescence spectrometry (TXRF) and radioisotope excited X-ray fluorescence spectrometry (XRF). The objective was to establish whether the elemental content of bee honey, in particular, correlates with any useful information about the environment, variety of honey, etc. An attempt has also been made to determine the X-ray techniques' ability to compete with atomic absorption spectrometry (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES), with regard to elemental sensitivity, accuracy, sample preparation procedures, and in particular, economic performance, which is very important in selecting an appropriate technique for the analysis of large numbers of samples. The results confirm the advantages of the TXRF method for trace element analysis, but only when utilising monochromatic excitation and selecting a proper sample preparation procedure. The radioisotope XRF technique, which does not require any sample preparation, is still very competitive in analysis of elements with concentrations above a few ten ppm. Preliminary results also confirm some correlations between the elemental content of honey and the status of the environment, and encourage further work in this direction

Kump, P.; Ne?emer, M.; Šnajder, J.

1996-04-01

372

Depth profiling of element concentrations in stratified materials by confocal microbeam X-ray fluorescence spectrometry with polychromatic excitation.  

PubMed

The confocal microbeam X-ray fluorescence technique is a well-established analytical tool that is widely used for qualitative and quantitative analysis of stratified materials. There are several different reconstruction methods dedicated to this type of samples. However, these methods are applicable with monochromatic excitation only. The full description of matrix effects and geometrical effects for polychromatic X-ray photons in confocal geometry is a demanding task. In the present paper, this problem was overcome by the use of effective energy approximation. The reduction of the whole energy dimension into one effective value eliminates the necessity of integration over the primary beam energy range for a number of basic parameters. This simplification is attainable without loss of the accuracy of analysis. The proposed approach was validated by applying it to the reconstruction of element concentration depth profiles of stratified standard samples measured with tabletop confocal microbeam X-ray fluorescence setup and by comparing the obtained results of two independent algorithms. PMID:25307861

Wrobel, Pawel; Wegrzynek, Dariusz; Czyzycki, Mateusz; Lankosz, Marek

2014-11-18

373

Picosecond laser-pump, x-ray probe spectroscopy of GaAs  

Microsoft Academic Search

A laser-pump, x-ray probe spectroscopic experiment is described, and the results are shown. The Ga K? x-ray fluorescence following x-ray absorption, at the Ga K absorption edge was measured, and its increase due to excitation with subpicosecond pulses of laser light at 4.6 eV photon energy was determined. The x-ray absorption, and thus the fluorescence, is increased for about 200

B. W. Adams; M. F. DeCamp; E. M. Dufresne; D. A. Reis

2002-01-01

374

Picosecond laser-pump, x-ray probe spectroscopy of GaAs  

Microsoft Academic Search

A laser-pump, x-ray probe spectroscopic experiment is described, and the results are shown. The Ga Kalpha x-ray fluorescence following x-ray absorption, at the Ga K absorption edge was measured, and its increase due to excitation with subpicosecond pulses of laser light at 4.6 eV photon energy was determined. The x-ray absorption, and thus the fluorescence, is increased for about 200

B. W. Adams; M. F. Decamp; E. M. Dufresne; D. A. Reis

2002-01-01

375

Investigation of molecular mechanisms of action of chelating drugs on protein-lipid model membranes by X-ray fluorescence  

SciTech Connect

Protein-lipid films based on the enzyme alkaline phosphatase were subjected to the action of chelating drugs, which are used for accelerating the removal of heavy metals from the human body, and the elemental composition of the resulting films was investigated. Total-reflection X-ray fluorescence measurements were performed at the Berlin Electron Storage Ring Company for Synchrotron Radiation (BESSY) in Germany. A comparative estimation of the protective effect of four drugs (EDTA, succimer, xydiphone, and mediphon) on membrane-bound enzymes damaged by lead ions was made. The changes in the elemental composition of the protein-lipid films caused by high doses of chelating drugs were investigated. It was shown that state-of-the-art X-ray techniques can, in principle, be used to develop new methods for the in vitro evaluation of the efficiency of drugs, providing differential data on their actions.

Novikova, N. N., E-mail: nn_novikova@ns.crys.ras.ru [Kurchatov Institute, Russian Research Center (Russian Federation); Zheludeva, S. I.; Koval'chuk, M. V.; Stepina, N. D. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Erko, A. I. [Berlin Electron Storage Ring Company for Synchrotron Radiation (Germany); Yur'eva, E. A. [Ministry of Health of the Russian Federation, Moscow Research Institute of Pediatrics and Pediatric Surgery (Russian Federation)

2009-12-15

376

Synchrotron X-Ray Fluorescence Microscopy of Gallium in Bladder Tissue following Gallium Maltolate Administration during Urinary Tract Infection  

PubMed Central

A mouse model of cystitis caused by uropathogenic Escherichia coli was used to study the distribution of gallium in bladder tissue following oral administration of gallium maltolate during urinary tract infection. The median concentration of gallium in homogenized bladder tissue from infected mice was 1.93 ?g/g after daily administration of gallium maltolate for 5 days. Synchrotron X-ray fluorescence imaging and X-ray absorption spectroscopy of bladder sections confirmed that gallium arrived at the transitional epithelium, a potential site of uropathogenic E. coli infection. Gallium and iron were similarly but not identically distributed in the tissues, suggesting that at least some distribution mechanisms are not common between the two elements. The results of this study indicate that gallium maltolate may be a suitable candidate for further development as a novel antimicrobial therapy for urinary tract infections caused by uropathogenic E. coli. PMID:23877680

Sampieri, Francesca; Chirino, Manuel; Hamilton, Don L.; Blyth, Robert I. R.; Sham, Tsun-Kong; Dowling, Patricia M.; Thompson, Julie

2013-01-01

377

Optimizing the Elemental Sensitivity and Focal Spot Size of a Monolithic Polycapillary Optic Using Micro-X-Ray Fluorescence  

SciTech Connect

A commercial micro-X-ray fluorescence (MXRF) instrument with an aperture X-ray guide was used to compare elemental sensitivities and focal spot sizes with those obtained by focusing the source with a monolithic polycapillary optic retrofitted into the system. The capillary provided an intensity gain of 125 at 4 keV vs. using a pinhole beam collimator; however, this gain advantage declined with increasing analyte line energy as a result of the capillary being designed shorter than its optimal length to fit into the commercial instrument. A minimum capillary focal spot FWHM of 36 {micro}m was achieved, whereas the smallest pinhole aperture available of 50 {micro}m in diameter produced a focal spot width of 69 {micro}m FWHM. Hence, better MXRF lateral resolution could be obtained with the capillary with a simultaneous improvement in elemental sensitivity.

Worley, C.; Havrilla, G.; Gao, N.; Xia, Q.-F.

1998-10-01

378

X-RAY FLUORESCENCE ANALYSIS OF HANFORD LOW ACTIVITY WASTE SIMULANTS  

SciTech Connect

Savannah River National Laboratory (SRNL) was requested to develop an x-ray fluorescence (XRF) 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 XRF analytical methods that provide the rapid turnaround time (<8 hours) requested by the WTP, while providing sufficient accuracy and precision to determine waste composition variations. For Phase 1a, SRNL (1) evaluated, selected, and procured an XRF instrument for WTP installation, (2) investigated three XRF sample methods for preparing the LAW sub-sample for XRF analysis, and (3) initiated scoping studies on AN-105 (Envelope A) simulant to determine the instrument's capability, limitations, and optimum operating parameters. After preliminary method development on simulants and the completion of Phase 1a activities, SRNL received approval from WTP to begin Phase 1b activities with the objective of optimizing the XRF methodology. Three XRF sample methods used for preparing the LAW sub-sample for XRF analysis were studied: direct liquid analysis, dried spot, and fused glass. The direct liquid method was selected because its major advantage is that the LAW can be analyzed directly without any sample alteration that could bias the method accuracy. It also is the fastest preparation technique--a typical XRF measurement could be completed in < 1hr after sample delivery. Except for sodium, the method detection limits (MDLs) for the most important analytes in solution, the hold point elements, were achieved by this method. The XRF detection limits are generally adequate for glass former batching and product composition reporting, but may be inadequate for some species (Hg, Cd, and Ba) important to land disposal restrictions. The long term precision (24-hr) also was good with percent relative standard deviations (%RSDs) < 10 % for most elements in filtered solution. There were some issues with a few elements precipitating out of solution over time affecting the long term precision of the method. Additional research will need to be performed to resolve this sample stability problem. Activities related to methodology optimization in the Phase 1b portion of the study were eliminated as a result of WTP request to discontinue remaining activities due to funding reduction. These preliminary studies demonstrate that developing an XRF method to support the LAW vitrification plant is feasible. When funding is restored for the WTP, it is recommended that optimization of this technology should be pursued.

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

2006-05-08

379

Identifying Objects via Encased X-Ray-Fluorescent Materials - the Bar Code Inside  

NASA Technical Reports Server (NTRS)

Systems for identifying objects by means of x-ray fluorescence (XRF) of encased labeling elements have been developed. The XRF spectra of objects so labeled would be analogous to the external bar code labels now used to track objects in everyday commerce. In conjunction with computer-based tracking systems, databases, and labeling conventions, the XRF labels could be used in essentially the same manner as that of bar codes to track inventories and to record and process commercial transactions. In addition, as summarized briefly below, embedded XRF labels could be used to verify the authenticity of products, thereby helping to deter counterfeiting and fraud. A system, as described above, is called an encased core product identification and authentication system (ECPIAS). The ECPIAS concept is a modified version of that of a related recently initiated commercial development of handheld XRF spectral scanners that would identify alloys or detect labeling elements deposited on the surfaces of objects. In contrast, an ECPIAS would utilize labeling elements encased within the objects of interest. The basic ECPIAS concept is best illustrated by means of an example of one of several potential applications: labeling of cultured pearls by labeling the seed particles implanted in oysters to grow the pearls. Each pearl farmer would be assigned a unique mixture of labeling elements that could be distinguished from the corresponding mixtures of other farmers. The mixture would be either incorporated into or applied to the surfaces of the seed prior to implantation in the oyster. If necessary, the labeled seed would be further coated to make it nontoxic to the oyster. After implantation, the growth of layers of mother of pearl on the seed would encase the XRF labels, making these labels integral, permanent parts of the pearls that could not be removed without destroying the pearls themselves. The XRF labels would be read by use of XRF scanners, the spectral data outputs of which would be converted to alphanumeric data in a digital equivalent data system (DEDS), which is the subject of the previous article. These alphanumeric data would be used to track the pearls through all stages of commerce, from the farmer to the retail customer.

Schramm, Harry F.; Kaiser, Bruce

2005-01-01

380

Evaluation of the uncertainties associated with in vivo X-ray fluorescence bone lead calibrations  

NASA Astrophysics Data System (ADS)

An anthropometric leg phantom developed at the University of Cincinnati (UC) was used to evaluate the effects that changes in leg position and variation between subjects has on in vivo x-ray fluorescence (XRF) measurements of stable lead in bone. The changes in leg position that were evaluated include changes in source-phantom distance ranging between 0.0 mm and 30.0 mm and phantom rotation over 40 degrees. Source-phantom distance was determined to have a significant effect on XRF measurement results particularly at source-phantom distances greater than 10.0 mm. Rotation of the leg phantom through 40 degrees was determined to have no significant effect on XRF measurement results. Between subject factors that were evaluated include bone calcium content and overlying tissue thickness. Bone calcium content was determined to have a significant effect on XRF measurements when measuring lead in micrograms per gram bone material. However, if measurement results of micrograms of lead per gram calcium (or per gram bone mineral) is used the normalization method makes the change in calcium content not significant. Overlying tissue thickness was determined to have no significant effect on XRF measurement results with tissue thickness ranging between 5.7 and 11.62 mm. The UC leg phantom was modified to include a fibula bone phantom so that the effect that the fibula has on XRF measurement results could be evaluated. The fibula was determined to have no significant effect on XRF measurement results and in the future need not be incorporated into in vivo XRF calibration phantoms. A knee phantom was also developed for purposes of calibrations of in vivo XRF measurement of lead in the patella. XRF measurement results using this phantom were compared to results of XRF measurements made using the plaster-of-Paris (POP) phantoms. A significant difference was observed between the normalized count rates of the two phantom types when either micrograms of lead per gram of bone material or micrograms of lead per gram calcium (bone mineral) is used as the lead content. This difference is consistent with what is observed in real in vivo XRF measurements and indicates the need for the correction factors that are used.

Lodwick, Jeffrey C.

381

Quantification and localization of trace metals innatural plankton cells using a synchrotron X-ray fluorescence microprobe  

NASA Astrophysics Data System (ADS)

The accumulation of trace metals by planktonic protists influences the growth of primary producers, metal biogeochemical cycling, and metal bioaccumulation in aquatic food chains. Despite their importance, unequivocal measurements of trace element concentrations in individual plankton cells have not been possible to date. We have used the 2-ID-E side-branch hard x-ray microprobe at the Advanced Photon Source to measure trace elements in individual marine plankton cells. This microprobe employs zoneplate optics to produce the sub-micron spatial resolution and low background fluorescence required to produce trace element maps of planktonic protist cells ranging in size from 3 to >50 ?m. We have developed preservation, rinsing, and mounting protocols that remove most of the salt from our marine samples, thus simplifying the identification of unknown cells and reducing high Clrelated background fluorescence. We have also developed spectral modeling techniques that account for the frequent overlap of adjacent fluorescence peaks and non-uniform detector response. Finally, we have used parallel soft x-ray transmission and epifluorescence microscopy images to estimate C normalized trace element concentrations, identify functional cell types (e.g., photosynthetic vs. non-photosynthetic), and correlate cell structures with spatial patterns in trace element fluorescence.

Twining, B. S.; Baines, S. B.; Fisher, N. S.; Jacobsen, C.; Maser, J.

2003-03-01

382

X-ray Thomson scattering as a temperature probe for Gbar shock experiments  

NASA Astrophysics Data System (ADS)

In X-ray Thomson scattering (XRTS), spectrally-resolved spectrometry of probe x-rays scattered from matter gives an elastic (ionic) and an inelastic (electronic) feature, whose location, width, and amplitude can be analyzed for electron density and temperature. This diagnostic is complementary to traditional, mechanical EOS measurements which do not directly constrain temperature. XRTS has been demonstrated on planar dynamic-loading experiments at the Omega laser, and a spectrometer has been constructed for use at the National Ignition Facility (NIF). We plan to obtain XRTS measurements into the Gbar regime using hohlraum-driven converging shocks at NIF. In these experiments, the radial profile through the sample at any instant of time varies greatly, though the XRTS signal is dominated by the densest region, which is close to the shock front where simultaneous radiography obtains an EOS measurement.

Döppner, T.; Kritcher, A. L.; Kraus, D.; Glenzer, S. H.; Bachmann, B. L.; Chapman, D.; Collins, G. W.; Falcone, R. W.; Hawreliak, J.; Landen, O. L.; Lee, H. J.; Le Pape, S.; Ma, T.; Neumayer, P.; Redmer, R.; Swift, D. C.

2014-05-01

383

Design of novel x-ray optical system for rocket experiment  

NASA Astrophysics Data System (ADS)

A novel design of X-ray optical system - concentrator for astrophysical rocket experiment is investigated. The proposed system is based on four modules with Kirkpatrick-Baez (KB) configuration allowing usage of multi-foil mirrors arranged to parabolic profile. The KB modules are supplemented by rotationally symmetrical parabolic segments. This X-ray optical system effectively uses a circular aperture. The KB modules are placed in four quadrants while the segments are set into a Cartesian cross between the KB modules. Studied optical system is under consideration for the student rocket experiment of University of Colorado that should verify function of NIST's energy-dispersive detector based on Transition Edge Sensors (TES microcalorimeters).

Pina, L.; Hudec, R.; Tichy, V.; Inneman, A.; Cerna, D.; Sveda, L.; Marsik, J.; Marsikova, V.; Cash, W.; Shipley, A. F.; Zeiger, B. R.; Rogers, T. D.

2013-09-01

384

Educational x-ray experiments and XRF measurements with a portable setup adapted for the characterization of cultural heritage objects  

NASA Astrophysics Data System (ADS)

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 modules have been developed on the basis of this setup. Module 1 comprises a series of x-ray laboratory exercises investigating basic principles, such as the verification of Moseley's law, Compton's law and the Lambert-Beer law. Module 2 concerns the calibration of the XRF with reference materials, aiming to get quantitative measurements of the elemental composition of objects of cultural interest. The application of the calibrated experimental setup is demonstrated with indicative measurements of metal objects and pigments of wall paintings, in order to discuss their spectra, and their qualitative and quantitative analyses. The setup and the applied experiments are designed as an educational package of laboratory exercises on the one hand for students in natural sciences, and on the other for the education of students who will work in the field of cultural heritage, such as conservation science or archaeological science.

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

2010-05-01

385

Beamline 14B at Photon Factory: Precision x-ray optics experiment facility (abstract)  

Microsoft Academic Search

The beamline 14B at Photon Factory is one of three branches of the 5T vertical superconducting wiggler beamline (BL14) at Photon Factory. This branch is used mainly for precision x-ray optics experiments and partly for commissioning a low-angle double-crystal spectrometer and a gas-phase scattering apparatus. A double-crystal fixed-exit monochromator was installed on this beamline; it has two offset positions, 200

T. Ishikawa; M. Ando; S. Kikuta

1989-01-01

386

The solar X-ray/cosmic gamma-ray burst experiment aboard Ulysses  

NASA Technical Reports Server (NTRS)

The scientific objectives of the Ulysses solar X-ray/cosmic gamma-ray burst experiment, and the unique features of the Ulysses mission which will help to achieve them are described. After a discussion of the special design constraints imposed by the mission, the sensor systems, consisting of two CsI scintillators and two Si surface barrier detectors covering the energy range 5-150 keV are described. Their operating modes and inflight performance are also given.

Hurley, K.; Sommer, M.; Atteia, J.-L.; Boer, M.; Cline, T.; Cotin, F.; Henoux, J.-C.; Kane, S.; Lowes, P.; Niel, M.

1992-01-01

387

Observation of the X-ray pulsar A0535 + 26 with the FIGARO II experiment  

NASA Astrophysics Data System (ADS)

The FIGARO II experiment observed the transient X-ray pulsar A0535 + 26 in the 0.15-4 MeV range, only 11.1 +/- 4 days after an expected outburst. We found evidence for periodicity at 103.2 sec close to the extrapolated value. The light-curve and the spectral shape of this low energy gamma-ray emission are presented here.

Olive, J. F.; Agrinier, B.; Barouch, E.; Comte, R.; Costa, E.; Cusumano, G. C.; Gerardi, G.; Mandrou, P.; Masnou, J. L.; Massaro, E.; Matt, G.; Mineo, T.; Niel, M.; Parlier, B.; Sacco, B.; Salvati, M.; Scarsi, L.

1993-01-01

388

X-ray fluorescence analysis of terbium oxide and oxalate for rare earth impurities  

Microsoft Academic Search

Summary A method for the determination of samarium, europium, gadolinium, dysprosium, holmium and yttrium oxides in terbium oxide is described. The sample is converted to terbium oxalate, mixed with boric acid binder in the ratio 2:1, pelleted at a pressure of 20 tons over a boric acid backing pellet and irradiated with X-rays from a tungsten tube operated by Philips

L. C. Chandola; I. J. Machado; A. N. Mohile

1976-01-01

389

In-situ Measurements of Colloid Transport and Retention Using Synchroton X-ray Fluorescence  

Technology Transfer Automated Retrieval System (TEKTRAN)

The physics regarding the retention and mobilization of colloids in saturated and unsaturated conditions remains poorly understood, partially due to 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 th...

390

POLYMER FILM STANDARDS FOR X-RAY FLUORESCENCE SPECTROMETERS (JOURNAL VERSION)  

EPA Science Inventory

Sets of thin polymer films were developed to serve as standards for XRF analysis of the following 18 elements in aerosol particle samples: Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, As, Rb, Sr, Zr, Cd, Sb, Ba, and Pb. Each film contains a pair of elements having non-interfering x-ray...

391

A new aperture for neutron and x-ray imaging of inertial confinement fusion experiments.  

PubMed

Recent neutron imaging of experiments at the National Ignition Facility has provided useful information about the hotspot shape and cold-fuel distribution and has also given insight into avenues for improvement. Neutron image reconstruction depends on accurate pointing information because the point-spread function of the neutron aperture is not shift invariant. Current pointing techniques are limited in their accuracy and rely upon detailed information about the as-built structure of the array, which is difficult to determine. We present a technique for extracting high-precision pointing information from both neutron and x-ray images, and a new aperture design with features to facilitate this technique, and allow future co-registration of neutron and x-ray images. PMID:23127029

Danly, C R; Grim, G P; Guler, N; Intrator, M H; Merrill, F E; Volegov, P; Wilde, C H

2012-10-01

392

High planarity x-ray drive for ultrafast shockless-compression experiments  

SciTech Connect

A spatially planar ({delta}time/time{approx}0.2%) longitudinal stress drive extending over millimeter scale lengths is used to shocklessly compress an aluminum sample to a peak stress of 210 GPa over nanosecond time scales. Direct laser irradiation onto the inner wall of an Au halfraum creates an x ray distribution with a near-uniform blackbody temperature of up to 137 eV. The x rays ablate material from a low-Z foil in a region of planarity closely matched to the diameter of the halfraum. The resultant ablatively driven shock is converted into a ramp-stress-wave in a secondary aluminum target through unloading across an intermediate vacuum gap. Higher peak stresses and shorter associated risetimes result from increasing input laser energy. Ramp-compression experiments can provide single shot equation-of-state data close to the isentrope, information on the kinetics of phase transformations, and material strength at high pressures.

Smith, Raymond F.; Pollaine, Stephen M.; Moon, Stephen J.; Lorenz, K. Thomas; Celliers, Peter M.; Eggert, Jon H.; Park, Hye-Sook; Collins, Gilbert W. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

2007-05-15

393

X-ray conversion efficiency in vacuum hohlraum experiments at the National Ignition Facility  

SciTech Connect

X-ray fluxes measured in the first 96 and 192 beam vacuum hohlraum experiments at the National Ignition Facility (NIF) were significantly higher than predicted by computational simulations employing XSN average atom atomic physics and highly flux-limited electron heat conduction. For agreement with experimental data, it was found that the coronal plasma emissivity must be simulated with a detailed configuration accounting model that accounts for x-ray emission involving all of the significant ionization states. It was also found that an electron heat conduction flux limit of f= 0.05 is too restrictive, and that a flux limit of f= 0.15 results in a much better match with the NIF vacuum hohlraum experimental data. The combination of increased plasma emissivity and increased electron heat conduction in this new high flux hohlraum model results in a reduction in coronal plasma energy and, hence, an explanation for the high ({approx}85%-90%) x-ray conversion efficiencies observed in the 235 < T{sub r} < 345 eV NIF vacuum hohlraum experiments.

Olson, R. E. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Suter, L. J.; Callahan, D. A.; Rosen, M. D.; Dixit, S. N.; Landen, O. L.; Meezan, N. B.; Moody, J. D.; Thomas, C. A.; Warrick, A.; Widmann, K.; Williams, E. A.; Glenzer, S. H. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Kline, J. L. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2012-05-15

394

Transient pulsar dynamics in hard x-rays: Prognoz 9 and GRIF "Mir" space experiments data  

E-print Network

The long-term observations of the Galactic Centre as well as the Galactic anti-Centre regions in hard X-rays (10-300 keV) were made in experiments on board Prognoz-9 satellite and "Mir" orbital station (GRIF experiment). Some transient pulsars including A0535+262, GS1722-36, 4U1145-619, A1118-615, EXO2030+37, Sct X-1, SAX J2103.5+4545, IGR 16320-4751, IGR 16465-4507 were observed. The pulsation flux components of A0535+26 and GS1722-36 X-ray emission were revealed at significant level. For other observed pulsars the upper limits of pulsation intensity were obtained. The mean pulsation profiles of A0535+26 in different energy ranges as well as the energy spectra were obtained at different stages of outburst decreasing. The pulsation intensity-period behavior does not contradict the well-known correlation between spin-up rate and X-ray flux, while the stable character of the energy spectrum power index indicates on the absence of thermal component. The energy spectrum and mean pulsation profiles were also obtained for one time interval of GS1722-36 observations. The upper limits of pulsation fluxes obtained for other observed transient pulsars at the orbital phases more than 0.14 correspond the quiescent state or final stage of the first type outburst.

M. I. Kudryavtsev; S. I. Svertilov; V. V. Bogomolov

2006-10-30

395

X-ray Experiments for Students at the SLS Optics Beamline  

SciTech Connect

We present a X-ray training course for students. The course covers fundamental properties of synchrotron radiation and basic techniques like scattering and absorption. We prepared ten experiments together with a tutorial. The whole course takes about a week. A first student group from the University of Copenhagen passed the course in June 2009. The experiments were performed at the optics beamline of the Swiss Light Source which can be part-time allocated for training purposes. Two experiments are described in more detail: scattering from a hanging drop of water turning into ice and measurement of the power of a pink synchrotron beam using a simple calorimeter.

Flechsig, U.; Jaggi, A.; Krempasky, J.; Oberta, P.; Spielmann, S.; Veen, J. F. van der [Paul Scherrer Institut, Swiss Light Source, 5232 Villigen PSI (Switzerland); Als-Nielsen, J. [University of Copenhagen, Universitetsparken 5, DK 2100 Copenhagen (Denmark)

2010-06-23

396

Gadolinium Deposition in Nephrogenic Systemic Fibrosis: An Examination of Tissue using Synchrotron X-ray Fluorescence Spectroscopy  

SciTech Connect

Nephrogenic systemic fibrosis is a fibrosing disorder associated with gadolinium (Gd)-based contrast agents dosed during renal insufficiency. In two patients, Gd deposition in tissue affected by nephrogenic systemic fibrosis was quantified using inductively coupled plasma mass spectrometry. The presence of Gd was confirmed and mapped using synchrotron x-ray fluorescence spectroscopy. Affected skin and soft tissue from the lower extremity demonstrated 89 and 209 ppm ({micro}g/g, dry weight, formalin fixed) in cases 1 and 2, respectively. In case 2, the same skin and soft tissue was retested after paraffin embedding, with the fat content removed by xylene washes, and this resulted in a measured value of 189 ppm ({micro}g/g, dry weight, paraffin embedded). Synchrotron x-ray fluorescence spectroscopy confirmed Gd in the affected tissue of both cases, and provided high-sensitivity and high-resolution spatial mapping of Gd deposition. A gradient of Gd deposition in tissue correlated with fibrosis and cellularity. Gd deposited in periadnexal locations within the skin, including hair and eccrine ducts, where it colocalized to areas of high calcium and zinc content. Because of the difficulty in obtaining synchrotron x-ray fluorescence spectroscopy scans, tissue from only two patients were mapped. A single control with kidney disease and gadolinium-based contrast agent exposure did not contain Gd. Gd content on a gravimetric basis was impacted by processing that removed fat and altered the dry weight of the specimens. Gradients of Gd deposition in tissue corresponded to fibrosis and cellularity. Adnexal deposition of Gd correlated with areas of high calcium and zinc content.

High, W.; Ranville, J; Brown, M; Punshon, T; Lanzirotti, A; Jackson, B

2010-01-01

397

Imaging performance of a hybrid x-ray computed tomography-fluorescence molecular tomography system using priors  

SciTech Connect

Purpose: The performance is studied of two newly introduced and previously suggested methods that incorporate priors into inversion schemes associated with data from a recently developed hybrid x-ray computed tomography and fluorescence molecular tomography system, the latter based on CCD camera photon detection. The unique data set studied attains accurately registered data of high spatially sampled photon fields propagating through tissue along 360 deg. projections. Methods: Approaches that incorporate structural prior information were included in the inverse problem by adding a penalty term to the minimization function utilized for image reconstructions. Results were compared as to their performance with simulated and experimental data from a lung inflammation animal model and against the inversions achieved when not using priors. Results: The importance of using priors over stand-alone inversions is also showcased with high spatial sampling simulated and experimental data. The approach of optimal performance in resolving fluorescent biodistribution in small animals is also discussed. Conclusions: Inclusion of prior information from x-ray CT data in the reconstruction of the fluorescence biodistribution leads to improved agreement between the reconstruction and validation images for both simulated and experimental data.

Ale, Angelique; Schulz, Ralf B.; Sarantopoulos, Athanasios; Ntziachristos, Vasilis [Institute for Biological and Medical Imaging, Technische Universitaet Muenchen and Helmholtz Zentrum Muenchen, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)

2010-05-15

398

Imaging of pharmacokinetic rates of indocyanine green in mouse liver with a hybrid fluorescence molecular tomography/x-ray computed tomography system  

NASA Astrophysics Data System (ADS)

Pharmacokinetic rates have the potential to provide quantitative physiological and pathological information for biological studies and drug development. Fluorescence molecular tomography (FMT) is an attractive imaging tool for three-dimensionally resolving fluorophore distribution in small animals. In this letter, pharmacokinetic rates of indocyanine green (ICG) in mouse liver are imaged with a hybrid FMT and x-ray computed tomography (XCT) system. A recently developed FMT method using structural priors from an XCT system is adopted to improve the quality of FMT reconstruction. In the in vivo experiments, images of uptake and excretion rates of ICG in mouse liver are obtained, which can be used to quantitatively evaluate liver function. The accuracy of the results is validated by a fiber-based fluorescence measurement system.

Zhang, Guanglei; Liu, Fei; Zhang, Bin; He, Yun; Luo, Jianwen; Bai, Jing

2013-04-01

399

Determining the Conformation of an Adsorbed Br-PEG-Peptide by Long Period X-ray Standing Wave Fluorescence  

PubMed Central

Long period x-ray standing wave fluorescence (XSW) and x-ray reflectivity techniques are employed to probe the conformation of a Br-polyethylene glycol (PEG)-peptide adsorbate at the hydrated interface of a polystyrene substrate. The Br atom on this Br-PEG-peptide construct serves as a marker atom allowing determination by XSW of its position and distribution with respect to the adsorption surface with angstrom resolution. Adsorption occurs on native or ion beam modified polystyrene films that are spin coated onto a Si substrate and display either nonpolar or polar surfaces, respectively. A compact, oriented monolayer of Br-PEG-peptide can be formed with the peptide end adsorbed onto the polar surface and the PEG end terminating with the Br tag extending into the aqueous phase. The 108 – 141 Å distance of the Br atom from the polystyrene surface in this oriented monolayer is similar to the estimated ~150 Å length of the extended Br-PEG-peptide. This Br-polystyrene distance depends upon adsorption time and surface properties prior to adsorption. Incomplete multilayers form on the polar surface after sufficient adsorption time elapses. By contrast, adsorption onto the nonpolar surface is submonolayer, patchy, and highly disordered with an isotropic Br distribution. Overall, this combination of x-ray surface scattering techniques with a novel sample preparation strategy has several advantages as a real space probe of adsorbed or covalently bound biomolecules at the liquid-solid interface. PMID:16089398

Crot, Carrie A.; Wu, Chunping; Schlossman, Mark L.; Trainor, Thomas P.; Eng, Peter J.; Hanley, Luke

2008-01-01

400

A high-quality multilayer structure characterization method based on X-ray fluorescence and Monte Carlo simulation  

NASA Astrophysics Data System (ADS)

X-ray fluorescence (XRF) is a well known nondestructive technique. It is also applied to multilayer characterization, due to its possibility of estimating both composition and thickness of the layers. Several kinds of cultural heritage samples can be considered as a complex multilayer, such as paintings or decorated objects or some types of metallic samples. Furthermore, they often have rough surfaces and this makes a precise determination of the structure and composition harder. The standard quantitative XRF approach does not take into account this aspect. In this paper, we propose a novel approach based on a combined use of X-ray measurements performed with a polychromatic beam and Monte Carlo simulations. All the information contained in an X-ray spectrum is used. This approach allows obtaining a very good estimation of the sample contents both in terms of chemical elements and material thickness, and in this sense, represents an improvement of the possibility of XRF measurements. Some examples will be examined and discussed.

Brunetti, Antonio; Golosio, Bruno; Melis, Maria Grazia; Mura, Stefania

2015-02-01

401

Pigments Elementary Chemical Composition Study of a Gainsborough Attributed Painting Employing a Portable X-Rays Fluorescence System  

SciTech Connect

The investigated painting, identified with the title 'The woodman', is attributed to Thomas Gainsborough (XVIII century) and is under investigation at the Laboratory of Conservation Science (LACICOR), CECOR/EBA/UFMG. The measurements were carried out with a portable X-rays fluorescence (XRF) system constituted of a X-rays tube with Ag anode, a Si PIN - diode detector, nuclear electronic chain and a special designed mechanical system for the detector and X-ray tube positioning, that enables angular and XYZ movements of the excitation-detection system. The employed voltage and current intensity were 17 kV and 3 mA, respectively. The time of acquisition for each measurement was 500 s. XRF spectra were analyzed using the AXIL-WinQXAS software. Three measurements in each of the following regions of the painting were done: face, leaves, arm, sky and firewood. The carried out analysis indicated the following pigments: White (lead white and calcium sulfate, identified by the elements Pb, Ca and S), Blue (Prussian blue, identified by the key element Fe), Red (Vermilion, identified by the elements Hg and S) and Brown (mixture of Fe and Mn oxides, identified by the elements Fe and Mn). Elements belonging to modern pigments corresponding to the same colors were absent in the analyzed spectra.

Appoloni, C. R.; Blonski, M. S. [State University of Londrina, Department of Physics, Londrina, PR (Brazil); Parreira, P. S.; Souza, L. A. C. [Federal University of Minas Gerais, EBA/CECOR/LACICOR Belo Horizonte, MG (Brazil)

2007-02-12

402

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

403

Radioisotope X-ray fluorescence and neutron activation analyses of the trace element concentrations of the rainbow trout  

NASA Astrophysics Data System (ADS)

The muscles and livers of the ten rainbow trouts ( Oncorhynchus mykiss; N, 1752) obtained from Sapanca, Aquaculture Facility of Aquatic Products Faculty, The University of Istanbul (Turkey), have been analysed quantitatively for some minor elements using the radioisotope energy dispersive X-ray fluorescence (EDXRF) and neutron activation analysis (NAA) methods. It was found that samples contain Na, K, Ca, Sc, Cs, Fe, Co, Cu, Zn, Se, Br, Rb, Sr, Au, La and Ce in different amounts. Comparison of the results with those of reference river fish samples indicated that agricultural rainbow trout samples from Sapanca region have higher Fe level.

Akyuz, T.; Bassari, A.; Bolcal, C.; Sener, E.; Yildiz, M.; Kucer, R.; Kaplan, Z.; Dogan, G.; Akyuz, S.

1999-01-01

404

The application of trend surface analysis to a portion of the Apollo 15 X-ray fluorescence data  

NASA Technical Reports Server (NTRS)

X-ray fluorescence data for 8 and 16 second time integrals gathered by Apollo 15 in circum lunar orbit were analyzed to determine the capability for chemical mapping of relatively small lunar features in a portion of Tranquillitatis and Serenitatis basins. Spatial mapping using trend surface analysis demonstrated that a useable signal could be extracted from Al/Si intensity ratios calculated for 8 second time spans. Reliability of the Al/Si ratio was enhanced when 16 second data were compiled using a sliding average technique. Residual anomalies from the trend surface mapping were identified and correlated with relatively small lunar surface features.

Podwysocki, M. H.; Weidner, J. R.; Andre, C. G.; Bickel, A. L.; Lum, R. S.; Adler, I.; Trombka, J. I.

1974-01-01

405

Study of the correlation between the coal calorific value and coal ash content using X-ray fluorescence analysis  

NASA Astrophysics Data System (ADS)

In this paper we have studied the possibility of determining the chemical elements in coal samples using X-ray fluorescence analysis and have found a relationship between the coal calorific value and its ash content with the coal moisture accounting. The amount of coal ash can be determined by the content of the basic chemical elements, such as Si, Sr, Fe, and Ca. It was concluded that the calorific value of coal can be estimated from the ash content in coal without the calorimetric measurements. These correlation coefficients were calculated for coal from several coal mines in Mongolia. The results are in good agreement with the results of chemical analysis.

Bolortuya, D.; Zuzaan, P.; Gustova, M. V.; Maslov, O. D.

2013-12-01

406

Analytical characterization of artists' pigments used in old and modern paintings by total-reflection X-ray fluorescence  

NASA Astrophysics Data System (ADS)

The analytical characterization of artists' pigments is a most helpful tool for art history, conservation and restoration of paintings. A very gentle method of ultra-microsampling was developed that is especially applicable to paintings under restoration. It provides a sample mass of about 1 ?g and is virtually non-destructive. This minute amount is sufficient for total-reflection X-ray fluorescence (TXRF) to determine most of those elements building inorganic pigments. The convenient and fast method was applied to oil paintings. Various pigments were identified and their mixing proportion was determined even quantitatively.

Klockenämper, R.; von Bohlen, A.; Moens, L.; Devos, W.

1993-02-01

407

Internal standards in fluorescent X-ray spectroscopy1 1 Publication authorized by the Director, U.S. Geological Survey.  

USGS Publications Warehouse

The use of internal standards in the analysis of ores and minerals of widely-varying matrix by means of fluorescent X-ray spectroscopy is frequently the most practical approach. Internal standards correct for absorption and enhancement effects except when an absorption edge falls between the comparison lines or a very strong emission line falls between the absorption edges responsible for the comparison lines. Particle size variations may introduce substantial errors. One method of coping with the particle size problem is grinding the sample with an added abrasive. ?? 1955.

Adler, I.; Axelrod, J.M.

1955-01-01

408

Laboratory Tests of a Handheld X-Ray Fluorescence Spectrometer: A Tool for Planetary Exploration  

NASA Astrophysics Data System (ADS)

Maximizing the science return from a mission to another planetary surface involves the integration of science objectives with deployable technologies that enable the collection of data and samples. For long duration manned missions, it is likely that more samples will be collected than can be returned to Earth due to mass limits. A niche exists for technologies that help prioritize samples for return, provide data for future sample handling and curation, and characterization for samples that are not returned to Earth. To fill this niche, hardware and protocols for field instruments are currently being developed and evaluated at NASA Johnson Space Center and Arizona State University. Our goal is to develop an easily used, environmentally isolated facility as part of the astronaut surface habitat for preliminary sample characterization and down-selection. NASA has constructed a prototype, GeoLab, as a testbed for evaluating the scientific applicability and operational considerations of various analytical instruments. One instrument under evaluation is a small, portable x-ray fluorescence (XRF) spectrometer that can be also be used by astronaut explorers as part of their field gear while on scientific sorties, or on robotic field assistants. We report on preliminary usability tests for commercially available handheld XRF instruments. These instruments collect data by contacting the surface of a rock or sediment sample with an 8 mm-wide sensor window. Within 60 seconds, the devices can provide relatively precise data on the abundance of major and trace elements heavier than Na. Lab-based handheld XRF analyses of terrestrial and lunar samples, compared with those made with full-scale laboratory XRF systems, show good correlation, but we continue to investigate potential sources of error and the need for careful calibration with standards of known composition. Specifically, we use a suite of five terrestrial and five lunar basalts, all well characterized by conventional XRF technology, to evaluate the handheld technology. All of these samples are fine-grained and homogeneous, and were selected to eliminate effects introduced to the data by inconsistencies in the sample matrix, or added complexities like increased vesicularity or phenocryst content. Our calibration curves are built from smooth, sawed surfaces. We have examined all major elements, minus Na (which falls below the instrument sensitivity). Initial tests show that reproducible and reliable calibration curves are produced for Ca, Fe, Al, Ti, and Si, but the curves produced for Mg, Mn, K and P include greater uncertainties. We are currently investigating how the instrument signal variably drops off as a function of surface roughness and distance to the instrument window. Through studies such as these in the simulated GeoLab setting, we can better understand the instrument's capabilities in a field environment, both on Earth and for potential future missions to other planetary surfaces.

Young, K. E.; Evans, C. A.; Hodges, K.

2011-12-01

409

A test cassette for x-ray-exposure experiments at the National Ignition Facility  

SciTech Connect

We present the design and operation of a test cassette for exposure of samples to radiation environments at the National Ignition Facility. The cassette provides options for square and round samples and exposure areas; the cassette provides for multiple levels of filtration on a single sample, which allows dynamic range in experiments. The samples had normal lines of sight to the x-ray source in order to have uniform x-ray illumination. The incident x-radiation onto the samples was determined by the choice of filter thicknesses and materials. The samples were held at precise locations, accurate to within a few hundred microns, in the target chamber in order to have a known fluence incident. In the cassette, the samples were held in place in such a way that a minimal ''line contact'' allows them to have the maximal mechanical response to the x-ray load. We present postshot images of the debris found on films used for filters, and pre- and postexposure specimens.

Fournier, K. B.; Celeste, J.; Rekow, V.; Bopp, D. R.; May, M. J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Fisher, J. H.; Horton, R.; Newlander, C. D. [Gray Research, Inc., 655 Discovery Drive, Suite 300, Huntsville, Alabama 35806 (United States); Jenkins, P.; Trautz, K. [Naval Research Laboratory, Washington, DC 20375 (United States)

2010-07-15

410

A new anthropometric phantom for calibrating in vivo measurements of stable lead in the human leg using X-ray fluorescence  

SciTech Connect

A new anthropometric phantom has been developed for calibrating in vivo measurements of stable lead deposited in bone using x-ray fluorescence. The phantom reproduces the shape of the mid shaft of the adult human leg and is fabricated using polyurethanes and calcium carbonate to produce materials that exhibit the same density, energy transmission, and calcium content as cortical bone, bone marrow, and muscle. The phantom includes a removable tibia fabricated using simulants for cortical bone and bone marrow to which a precise amount of stable lead has been added to cortical bone. The formulations used in fabricating the new anthropometric phantom are much more uniform in density and composition than the conventional phantom made from Plexiglas cylinders filled with plaster-of-Paris. The energy spectrum from an x-ray fluorescence measurement of the phantom using a {sup 109}Cd source is indistinguishable from an in vivo x-ray fluorescence measurement of the human leg, demonstrating that the materials used in the phantom exhibit the same radiological properties as human tissue. Likewise, results from x-ray fluorescence measurements of the phantom exhibit the same positional dependency as the human leg and vary by approximately 36% when, for example, the phantom containing 54 ppm of stable lead in the tibia was rotated by only 15 degrees. The detection limit for a 30 min {sup 109}Cd K shell x-ray fluorescence in vivo measurement is approximately 20 ppm determined from a background measurement using the new phantom containing no added lead in the muscle, bone, or bone marrow. The new anthropometric phantom significantly improves in vivo x-ray fluorescence calibration measurements by (1) faithfully reproducing the anatomy of the human leg, (2) having components that exhibit radiological properties similar to that of human tissue, and (3) providing a realistic calibration standard that can be used for in vivo x-ray fluorescence intercomparison measurements.

Spitz, H.; Jenkins, M.; Lodwick, J.; Bornschein, R.

2000-02-01

411

A Green Fluorescent Protein Containing a QFG Tri-Peptide Chromophore: Optical Properties and X-Ray Crystal Structure  

PubMed Central

Rtms5 is an deep blue weakly fluorescent GFP-like protein (, 592 nm; , 630nm; ?F, 0.004) that contains a 66Gln-Tyr-Gly chromophore tripeptide sequence. We investigated the optical properties and structure of two variants, Rtms5Y67F and Rtms5Y67F/H146S in which the tyrosine at position 67 was substituted by a phenylalanine. Compared to the parent proteins the optical spectra for these new variants were significantly blue-shifted. Rtms5Y67F spectra were characterised by two absorbing species (, 440 nm and 513 nm) and green fluorescence emission (, 440 nm; , 508 nm; ?F, 0.11), whilst Rtms5Y67F/H146S spectra were characterised by a single absorbing species (, 440 nm) and a relatively high fluorescence quantum yield (?F, 0.75; , 440 nm; , 508 nm). The fluorescence emissions of each variant were remarkably stable over a wide range of pH (3–11). These are the first GFP-like proteins with green emissions (500–520 nm) that do not have a tyrosine at position 67. The X-ray crystal structure of each protein was determined to 2.2 Å resolution and showed that the benzylidine ring of the chromophore, similar to the 4-hydroxybenzylidine ring of the Rtms5 parent, is non-coplanar and in the trans conformation. The results of chemical quantum calculations together with the structural data suggested that the 513 nm absorbing species in Rtms5Y67F results from an unusual form of the chromophore protonated at the acylimine oxygen. These are the first X-ray crystal structures for fluorescent proteins with a functional chromophore containing a phenylalanine at position 67. PMID:23071789

Byres, Emma; Rossjohn, Jamie; Devenish, Rodney J.; Olsen, Seth; Wilce, Matthew C. J.; Prescott, Mark

2012-01-01

412

Measurement of mass attenuation coefficients of biological materials by energy dispersive X-ray fluorescence spectrometry  

Microsoft Academic Search

The mass attenuation coefficients for cornea taken from keratitis patient and soft contact lens (-1.75, -3.75, -4 dioptres), leiomyomata uteri and uterus were measured in the X-ray energy (5.9keV) using a SiLi detector and Fe55 annular source. Full details of the experimental method, experimental set up, the procedure of sample preparation and the results within estimated error are presented. Energy

N. Ekinci; N. Astam

2007-01-01

413

Inelastic X-ray scattering experiments on B[subscript 4]C under high static pressures  

SciTech Connect

Boron K-edge inelastic X-ray scattering experiments were performed on clean B{sub 4}C and shock impact recovered boron carbide up to 30 GPa and at ambient temperature to understand the pressure induced bonding changes. The spectral features corresponding to the boron site in the interlinking chain remained unchanged up to 30 GPa. The results of our experiments indicate that pressure induces less distortion to the boron sites and the local amorphization observed in the previous reports are due to the rearrangement of carbon atoms under extreme conditions without affecting the boron environment.

Kumar, Ravhi S.; Dandekar, Dattatraya; Leithe-Jasper, Andres; Tanaka, Takaho; Xiao, Yuming; Chow, Paul; Nicol, Malcolm F.; Cornelius, Andrew L. (UNLV); (MXPL-M); (CIW); (USARL)

2010-05-04

414

Beamline 14B at Photon Factory: Precision x-ray optics experiment facility (abstract)  

NASA Astrophysics Data System (ADS)

The beamline 14B at Photon Factory is one of three branches of the 5T vertical superconducting wiggler beamline (BL14) at Photon Factory. This branch is used mainly for precision x-ray optics experiments and partly for commissioning a low-angle double-crystal spectrometer and a gas-phase scattering apparatus. A double-crystal fixed-exit monochromator was installed on this beamline; it has two offset positions, 200 and 500 mm. In order to avoid the leak of high-energy x rays from the monochromator chamber, the first crystal is shielded by lead with a rotatable 2? window inside the vacuum chamber. A precision x-ray optics experiment facility consists of two vertical axis goniometers designed for the use of vertical polarization. Rough rotation (360° with the finest step of 3.24 arcsec) and fine rotation (within 6°, the finest step of 0.01 arcsec) are changed with a clutch. A rotary encoder with precision of 1.0 arcsec is equipped. A double-crystal aligner mounted on one of the precision goniometers is constructed to make another double-crystal arrangement. Combining the beamline double-crystal monochromator with this aligner, we can make a fixed-exit four-crystal monochromator of (+n,-n,-m,+m) setting, known as the high resolution x-ray optics in energy as well as momentum. Two independent microcomputer control systems are used for beamline monochromator and experimental facility. These two systems are connected by a serial communication (RS-232C) line via a software controlled line selector. This makes it quite easy for user-made equipment to control the beamline monochromator synchronously by its own control system. A low-angle double-crystal spectrometer was further constructed to characterize synthetic multilayers. This spectrometer consists of two ?-2? goniometers mounted on x- (used for vertical axis) or xz- (used for horizontal axis) translation stage. These goniometers are mounted on independent carriers of a y-translation stage along the x-ray beam.

Ishikawa, T.; Ando, M.; Kikuta, S.

1989-07-01

415

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

SciTech Connect

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

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

2003-01-24

416

Determination of the mass attenuation coefficients for X-ray fluorescence measurements correction by the Rayleigh to Compton scattering ratio  

NASA Astrophysics Data System (ADS)

X-ray fluorescence technique plays an important role in nondestructive analysis nowadays. The development of equipment, including portable ones, enables a wide assortment of possibilities for analysis of stable elements, even in trace concentrations. Nevertheless, despite of the advantages, one important drawback is radiation self-attenuation in the sample being measured, which needs to be considered in the calculation for the proper determination of elemental concentration. The mass attenuation coefficient can be determined by transmission measurement, but, in this case, the sample must be in slab shape geometry and demands two different setups and measurements. The Rayleigh to Compton scattering ratio, determined from the X-ray fluorescence spectrum,